Power Take-Offs (PTOs) are designed to pick up engine power through rotation and transfer the power to another piece of equipment. For this to work, a piece of equipment can be mounted to the PTO or it can be connected by a driveshaft. The process begins with the PTO input gears meshing with one of the gears in a vehicle’s transmission starting the rotation. This rotation created from the engine drives the transmission and results in turning the PTO gear and rotating the PTO output shaft. Input gears must mesh properly with the transmission’s PTO drive gear for the PTO to work. But there are a series of gears that must be considered to determine the final output ratio of the PTO.Gear measurement terms
When analyzing the gears, a measurement term to be familiar with is gear pitch. Gear pitch is the measure of the size of the teeth and is determined by the number of teeth in a given area. To calculate the gear pitch, you would divide the number of teeth by the pitch diameter of the gear. Knowing the gear pitch is important since the PTO gear must have the same pitch as the transmission gear to function properly.
Another measurement term to be familiar with is gear ratio. Modification of the operating speed of the engine to the PTO driven device can be created through the gear ratio. To understand the PTO gear ratio, it measures the revolutions of the small and large gears. Looking at a smaller gear with 12 teeth driving a 24 teeth gear, the small gear makes a revolution with the larger gear only making half a revolution during the 1 small gear revolution. This means that the speed of the larger gear is half of the smaller gear, but the torque and twisting force is twice of the smaller gear.
The gear ratio in this scenario equates to the number of teeth in the driven gear (24) divided by the number of teeth in the driving gear (12). This results in a gear ratio of 2 to 1. The change in torque in this scenario is 1 to 2 resulting from dividing the number of teeth in the driving gear (12) over the driven gear (24). With the assumption of knowing the engine horsepower and the revolutions per minute (RPM) of the smaller gear, torque can be determined.
T = Horsepower x 5252/Speed (RPM) = Lbs. Ft. Torque
(As you can see from the above photograph, the two gears would lock as so with the red marked teeth)What does the gear ratio mean to me?
Product series can have multiple gear ratio options or have just one gear ratio option. To select what ratio makes the most sense, you must know the RPM you want your vehicle’s engine running at for the application and the required operating speed of the driven equipment being used in the application. The ratio of a series of gears creates the speed for the output shaft. Those gears include the input driver gear, the input ratio gear, and the output ratio gear. Their relationship to one another will determine how fast the output of the PTO is spinning in relationship to the engine. The required speed for the driven equipment must be known in order to select the proper PTO ratio. When utilizing pumps, flow rate and displacement are needed to be determined beforehand to make sure the pump input shaft will work with the given speed from the PTO.
210 Series PTO & 524 Series Rear Mount PTO
When looking into specific product series offered by Parker Chelsea, we want to highlight two different scenarios for series model codes. Starting with our new 210 Series for 2020 Ford Super Duty 10R140 transmissions, this series only has one gear ratio being 46/36 (internal ratio). When all of the gears in series are considered, the final output ratio is 144% of the engine speed. With this gear ratio, and using a 90% efficiency rating, specific pump options are offered for the 210 Series which include the CGP-P11, PGP-315 and P16 pumps. It is important to remember pump productivity is determined by the pump size in relation to the pump speed. Therefore, certain pump options may be more suitable than others depending upon the requirements of the application.
The 524 Series Rear Mount PTO is a little different compared to the 210 Series in relation with the gear ratio(s). The 524 Series has gear ratios of 1:1.00, 1:1.33, and 1:1.80. The design of the PTO itself is a two gear mechanically shifted Rear Mount PTO that is attached to rear mount apertures of a transmission. Rear mount apertures are becoming more common in the U.S. with European based transmissions becoming more popularized in the U.S. market. With the three gear ratios, this leads to different torque ratings being available in the market therefore increasing the number of applications that can be used with the 524 series along with optimizing the driven equipment.
Learn more about our 524 Series rear mount and 210 Series ten speed PTO today.
This article was contributed by Michael Mabrouk, marketing leadership associate, Chelsea Products Division, Parker Hannifin Corporation.
Transmissions within work truck applications are highly customizable leading to multiple Power Take-Off (PTO) designs aligning with the transmission, chassis and space claim requirements. When it comes to PTO manufacturers, different product series are created to align with the different transmission manufacturers in the market. When installing a PTO on a transmission, a common issue with the installation process is the clearance in the truck chassis with how much room is available for installation. This is where the design and unique configurations of the PTOs are maximized to best match with the transmission applications.
When an extended shaft makes sense
Installation clearance around the transmission can become problematic for many installers. Not only with the installation of the PTO itself, but attaching pumps may lead to situations of clearance issues that can, therefore, limit the type of pump sizes used. Allison is an example of a manufacturer that makes transmissions with customizable options. Popular transmissions from Allison are the 3000 and 4000 Series with the 3000 Series applying to medium duty applications and the 4000 series applying to heavy-duty applications. For Allison, PTO manufacturers have been creating product series that are designed for their transmission customization options. This is where extended shaft PTOs come into the discussion for the right application.
Extended shafts were designed to accommodate the Allison 3000 and Allison 4000 transmissions which feature a retarder or transmission mounted cooler. Transmission coolers help prevent transmissions from overheating from heavy hauling and towing. Transmission retarders help slow down vehicles when driving situations make it difficult to control the speed such as going downhill. These transmissions may have a transmission mounted cooler attached, a retarder attached or neither. Extended shaft PTOs provide a product series alternative to align with the transmission being used with a transmission mounted cooler and retarder since both impact clearance around the transmission. The design of the extended shaft product series help with these clearance issues.
Parker Chelsea offerings
Parker Chelsea’s extended shaft product series offerings include the 890 series and the 870-XL Series PTO. The 890 was the first extended shaft PTO. The design keeps the PTO close to the transmission and allows for a large pump to be mounted behind the transmission. The 890 output is just behind the transmission and does not extend beyond the transmission mounted cooler or retarder. The 890 also sometimes allows for a drive shaft to be mounted at a better angle or in the relatively clear area behind the transmission.
When comparing the 870-XL Series and the 890 Series to each other, they both have a torque capacity for each is up to 670 lbs.-ft / 908 Nm. The difference in the design of the two is the 890 Series extends 23 inches from the center of the aperture while the 870-XL Series extends 29 inches. There is approximately 6 to 7 inches of extra clearance with the 870-XL Series. If the 890 has an issue, the 870-XL extends beyond the transmission mounted cooler or retarder to help solve the clearance issue. Another feature with the 870-XL series is the pump flange is rotatable every 7.5 degrees. The pump should be able to be locked to whatever angle it fits best. The 870-XL also allows for larger pump fitment options.
The design of the 870-XL Series has the same main PTO body and internals common to the standard 870 Series. The 870-XL Series is a PowerShift PTO specifically designed for the Allison 3000/4000 Transmissions. The Allison 3000 Transmission is designed for medium-duty vehicles while the Allison 4000 Transmission applies to heavy-duty vehicles. The 870 series already provides a compact housing design that helps eliminate certain clearance issues.
It is important to note what transmission manufacturer is used in your truck application. With a transmission manufacturer like Allison, customization varies greatly with the design of a cooler and retarder. This has led to PTO manufacturers creating product series lines that best match with the unique customization of the Allison transmission and to help improve the end user customizable offering experience as well as the installation process. Other transmission manufacturers may have transmission offerings that have led to PTO manufacturers adapting and design product series to best serve the end-user with a proper PTO for best performance and offerings of customization.
To take a more in-depth look at the 890 and 870-XL PTO series offered by Parker Chelsea, check out our products page which newly features a selection filter of type of transmission manufacturer that will allow for you to easily categorize your search result based on the transmission manufacturer that you are inquiring about.
This article was contributed by Michael Mabrouk, marketing leadership associate, Chelsea Products Division, Parker Hannifin Corporation.
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A project involving a Parker EHPS (Electro Hydraulic Pump System) has underlined the significant advantages of adopting the latest electrification technologies as opposed to traditional industrial combustion engine (ICE)-driven systems for mobile heavy lifting applications. The project, conducted in partnership with a leading global OEM, showed how real-world challenges faced by all design engineers – reducing costs, increasing operational efficiency and protecting the environment – can be overcome.
The key point of note here is that developing the EHPS met an elementary industry need for decoupled loads and power distribution. A design concept of this type delivers better engine management, as energy storage and recovery functions form a key part of the overall solution. The system can be sized according to specific requirements, providing power on demand, eradicating waste and allowing for capturing returned energy when lowering the load. Contrast this to an ICE, which in heavy lifting applications is sized for peak energy demand and offers no energy storage or recovery capabilities, and the benefits are clear.
The opportunity for OEMs in the mobile machinery arena (and their end users) is significant, especially as an integrated solution such as the Parker EHPS can provide energy cost savings of circa 30% and up to 50% in some applications.
With regard to this specific project, development began back in 2012, with the first prototype emerging two years later. By 2016, Parker’s facility in Warwick had the project ownership and delivery responsibility transferred over. The first orders arrived in December of that year.
Breaking it down in engineering terms, the solution relies on an inverter-driven electro-hydraulic pump sub-system to deliver the lift-lower and telescope functions and enable energy recovery as materials descend under gravity. The IQAN control system and embedded Parker-derived software provide the system function and operational interface, while peripheral manifolds and system components facilitate important services in the wider hydraulics.
A key point is that by working in partnership with the OEM, Parker could validate in real-life the capabilities and savings possible with EHPS. In short, it could be proven that significant fuel savings would be achieved, while productivity gains with quicker responses in lifting, lowering and driving, were also demonstrated.
Since installation on the vehicle, the OEM reports it is expecting CO2 emissions to be reduced by up to 100 tonnes based on an annual running time of 5000 hours, providing yet another major benefit to the adoption of the system.
Ultimately, a decoupled solution like the EHPS offers a variety of critical benefits to those in the process of developing electric solutions, not least the opportunity to use a smaller ICE, or even eliminate it altogether. And that’s not forgetting gains relating to energy recovery, power on/off demand and the operation not being dependent on the ICE speed, or torque for that matter.
Learn more about Parker’s EHPS solution.
Article contributed by Ciprian Ciuraru, project manager, Mobile Hydraulic Systems Division Europe, Parker Hannifin Corporation.
The world of hydraulic motors is vast with numerous motor types available for various applications. To qualify as a hydraulic motor, a motor must utilize incompressible fluid to convert hydraulic pressure into torque and rotation. In applications that require low speeds (generally less than 1000 rpm) and high torques, an orbital-style, gerotor motor stands above the rest.What is an orbital motor?
An orbital-style motor consists of several roller vanes positioned in pockets around the inside diameter of a stator, that act as a guide for an internal rotor to orbit. The rotor’s rotation is achieved through a pressure differential created by fluid flow. Constantly shifting high- and low-pressure zones are created, resulting in smooth and consistent rotation. Once the fluid has moved through the motor, the fluid can be returned to a holding tank, or directly to the pump itself. The rotor drives an output shaft, which is connected via a “dogbone”-style drive link. This output shaft is connected to whatever is being driven (a wheel, auger, conveyor, etc.), and a high torque can be applied. This direct connection creates a smooth transfer of the required speed and torque for an application.What about a case drain?
There are two, smaller groups of low-speed, high-torque orbital motors, two-zone and three-zone. The primary difference between a two-zone and three-zone motor is the inclusion of a case-drain. A three-zone motor uses a case drain as a secondary outlet, where fluid can be returned to a tank (or pump), if the application’s pressure becomes too high. Alleviating this pressure aids cooling and can extend motor seal life. Additionally, the case drain line can drain excess internal oil leakage. This design feature allows three-zone motors to be linked in series for higher-pressure applications, while maintaining the flow levels of a two-zone torqmotor. In the case of a two-zone motor, the absence of a case drain means that extra adapters and hoses are not needed to connect a secondary outlet, making the entire system more cost effective. Two-zone motors can be equipped with high pressure shaft seals to bolster capability, but can not perform in the same, high pressure environments as a three-zone motor.
Parker Quality in a Three-Zone Package
Parker’s 3Z Series is the latest addition to the Parker Pump & Motor Division’s product portfolio. The 3Z line consists of two, three-zone, orbital-style motors. The orbital-style design reduces friction to a minimum, and increases the efficiency of the overall design, even at high pressures. The 3ZE and 3ZG models can provide up to 24GPM and 40GPM of flow, respectively, making the series ideal for applications across numerous markets. Find out more at www.discover.parker.com/3ZSeries.
The Pump & Motor Division is a market leader in gear pump and low speed-high torque gerotor motors, that continues to blaze a trail in the industry by developing new technologies while maintaining the high level of service synonymous with Parker. Between its two locations in North Carolina and Tennessee, the division employs decades of industry experience to better serve you and your application.Attending NTEA Work Truck Show 2020?
Visit us in Indianapolis, IN on March 3-6, 2020 at booth #3011 to see the latest in Parker products.
Article contributed by C.T. Lefler, market product manager, Parker Hannifin's Pump & Motor Division.
As multi-tasking becomes more prevalent in today’s day and age -- texting your mother while picking up groceries and simultaneously catching up on your latest podcast after taking your kids to practice -- it is no different with mobile machinery. In the name of increased productivity and output, operators are pushing machines to their limits by using all the oil in the system to support multi-function control.
Modern hydraulic systems are being developed with an increased awareness for optimizing efficiency and productivity. Depending on the function demands, many systems engineers are choosing a pre-compensated hydraulic load sense valve as it can provide an array of benefits for your hydraulic system including:
Compensator spools maintain a constant pressure drop across the main spool regardless of the change in work port pressure creating load-independent metering of the main spool.
Example: A 10 GPM spool will give your actuator 10 GPM no matter work port pressure fluctuation.
Pressure compensators combined with the load sense shuttle network within the valve allow operators to perform multiple work functions at once, increasing productivity and work output.
Example: Clamping an object while simultaneously performing swing, boom down and travel functions. *Limited to the amount of pump flow available*
Pressure limiters in a pre-compensated valve allow the work port pressure to be adjusted to a value that is less than the overall system pressure.
The challenge with pre-compensation
While pre-compensated valves are an excellent choice for increasing the efficiency and multi-function capability of your hydraulic system, a challenge can arise with the pump capacity. Machine operators who perform multiple functions at once are limited by the amount of oil available in the hydraulic system. Once all the oil is utilized, the pump has become saturated. Any request for oil past the saturation point will result in the highest loaded function losing oil and satisfying the lowest loaded function as oil will always go to the path of least resistance. See the figure below of a typical pre-compensated system.
Figure 1 : Functions 1, 2, and 3 are satisfied and the pump is saturated. The introduction of function 4 moves oil from function 3 (highest loaded) to satisfy function 4. The operator will start to lose functionality of function 3.
Parker’s solution to combatting pump saturation
To fix the issues that arise when saturating the pump, Parker L90 and K220 valves can flow share using anti-saturation technology. Anti-saturation utilizes a unique inlet and compensators to share the flow amongst all active machine functions. Instead of the highest loaded function losing oil, all active functions will have the same priority and slow to satisfy the need of the newly introduced function-- sharing the flow. See figure below:
Figure 2: Utilizing Parker Anti Saturation Compensators, all functions have the same priority and share the flow to satisfy function 4. Functions will slow but the operator will not lose functionality of the highest loaded function
The Value of the Parker L90 and K220
The ability to flow share can save your system hundreds, even thousands of dollars by not having to up size your pump for more capacity, saving on space claim while simultaneously boosting end-user productivity by allowing multi-functioning without the threat of saturating the system.
Combining anti-saturation compensators with the ability to pressure limit work functions and systems will also see an added boost in efficiency and cost savings on their cooler by mitigating the heat associated with using port reliefs to achieve the same pressure limiting functionality.
Mixing standard compensators with flow share compensators allows designers to designate flow priority for the standard compensated functions without having to design priority through external manifolds or options.
Example: Priority to steering. Any remaining flow is shared amongst other active functions. See figure below:
In an era of life hacks and multi-tasking to maximize efficiency, the Parker L90 and K220 are there to answer the call. Interested in cost savings while boosting efficiency? Contact your local Parker representative or contact us to see how we can optimize your hydraulic system.
This article was contributed by Brian Baranek, product sales manager, Parker's Hydraulic Valve Division.
Waste management vehicles perform many different functions. An easy way to understand how such functions operate can be represented by the concept of a hydraulic valve that actuates a cylinder by changing the direction a fluid is traveling. The industry demands each of these functions operate both safely and efficiently. A refuse front loader application has functions that can be grouped into high and low usage. The high usage functions are the arms, forks and packer while the low usage functions are the tailgate, tailgate lock and top door.
In a perfect world, it is desirable to have all these functions consolidated into one valve assembly. However, this can cause a problem where parallel path pressure from the high-usage functions find its way into the work ports of the low-usage functions. When this parallel path pressure from the high-usage functions follow the path of least resistance into the low-usage function work ports the potential result can manifest itself as function drift or pressure intensification.
Both function drift and pressure intensification are undesirable in hydraulic systems, with adverse effects on safety as well as efficiency. The solution for this is the application of tandem circuitry. When applied correctly tandem circuitry can isolate pressures and prevent function drift.Tandem circuitry
One way to prevent this unwanted function drift for the low usage functions is by placing the high usage, parallel sections first in the assembly and making the first low-usage section with tandem circuitry. By doing this, parallel path pressure cannot be conveyed to downstream work sections, and the low usage sections do not see high pressure in the power core when the high usage sections are operating.
Parker’s VA35 valve model line features this type of tandem circuitry. This product coupled with Parker’s specialists in refuse market provide the customer with a solution responsive to their needs. In addition to the refuse market, tandem circuitry solutions with the same type of arrangement could be applicable in other pieces of mobile equipment where function drift and pressure intensification are challenges to applications such as those found in material handling and construction markets.
Tandem circuitry offers a solution by which unnecessary complexity can be removed from the application. In the case of tandem circuitry this reduction in additional system complexity results in a corresponding reduction in system cost. The installation of the VA35 valve assembly with tandem circuitry eliminated the need for in-line pilot-operated checks offering a significant cost savings. This is based upon three low-usage functions per valve assembly. While the refuse market is the primary example of where substantial cost savings can be realized other mobile equipment system cost savings can be of value as well.
This article was contributed by Galen Methvin, product sales manager, Hydraulic Valve Division
Following new, more stringent Tier IV diesel engine emissions regulations, Rayco, an environmental equipment designer for the tree care and landscape industries, took the opportunity to develop a more efficient, powerful and compact stump cutter, the RG165T-R. In comparison to previous designs that utilized diesel engines, Rayco’s new stump cutter is centered around a powerful 165 HP gasoline engine.
As a result of the new gasoline design, the equipment’s envelope size was reduced and components were eliminated, such as, after treatment systems, diesel exhaust fluid and electronics. In addition to the robust gasoline engine, the RG 165T-R also packs a closed-circuit hydrostatic cutter wheel drive system that delivers full engine HP to the cutter wheel, completing every job in its path.
Stump cutting presents unique operating scenarios with each cycle. A pump and motor must be able to power through different obstacles at each job site. From technical support to high-quality hydraulic components to quick, on-time delivery, Parker enabled Rayco to develop its new industry-leading stump cutter.
The initial RG165T-R prototype was created using the Parker Series F12 182cc bent axis motor, along with a competitor’s 90cc closed circuit pump. However, during initial rounds of testing, the competitor’s 90cc closed circuit pump struggled with performance and reliability issues, along with the potential for long lead times.
When Rayco reached out to Parker applications team recommended an alternative - the compact, high-performance C Series 81cc hydrostat piston pump and promptly delivered a unit for testing. During subsequent testing of the Parker pump and motor combination, the team worked with Rayco engineers to dial in the performance.
By incorporating these two Parker components, Rayco engineers were able to exceed multiple performance targets. These targets included a 20 percent decrease in heat generation while increasing system efficiency by 10 percent over alternative test units. The C Series pump delivered excellent power density and paired perfectly with the 182cc F12 motor. The combination also translated into the optimal cutter wheel speed, which increased torque output to the cutter teeth by 10%. Another and unexpected benefit of the system was a tighter radius of the wood chips to the machine, resulting in less operational risk during the stump grinding process.
Parker’s Hydraulic Pump and Power Systems Division has been designing pumps and transmission for over 50 years. The division is the result of the Parker piston pump business's acquisition of Denison Hydraulics and the merger with the Parker Oildyne Division. These two businesses combined have extended Parker's product offering to include the quality compact hydraulic products and systems the division has been pioneering since 1955. To learn more about the products, visit www.parker.com/hps or contact the team.
Article contributed by Justin Wheeler, product manager, and Wes Jackson, application engineer for Parker Hannifin's Hydraulic Pump an Power Systems Division.
Traditionally, agricultural sprayer machines were custom-built on a four-wheel chassis. These custom-built units were heavy, expensive and not easily adapted to other farm applications. Sprayers are typically used to apply herbicides, insecticides and fertilizer. Naturally, it would be more practical if a machine that could be used for other functions – such as tilling, loading, and baling.
One manufacturer designed a retrofit using unconventional technologies which resulted in a three-wheel flotation spraying applicator. The new vehicle is less heavy, costs 20 to 50 percent less and is more versatile because it's designed to accomplish more than one function. The sprayer exerts lower ground pressure and more affordable than traditional machinery.
The three-wheeled commercial applicator was designed by retrofitting a mid-range (50 to 120 hp), two-wheel-drive tractor chassis with three major innovations:
A break from convention
Tractors of this size generally have hydraulically assisted steering using a hydraulic cylinder and mechanical linkage assembly. In place of the typical front-wheel steering cylinder, the manufacturer used a Helac helical hydraulic rotary actuator. Parker's Helac L30-65E-FT-180-S1-O-H rotary actuator produces a steering angle of up to 180 degrees and contains a bearing to support the load.
The rotary actuator is a part of the steering super structure, providing the strength and flexibility the vehicle requires without unnecessary weight, complexity and maintenance required of mechanical linages. It supports a thrust load of 8000 pounds and accommodates 423,000 pounds per inch of bending moment capacity. It transmits 55,000 pounds per inch of steering torque when fully loaded. The L30 series actuator’s design makes it capable of angular displacement of 360-degrees or more.
The tractor’s original-equipment hydraulic power unit supplies pressurized fluid for steering and other hydraulic functions. Maximum system pressure is 2950 psig with eight gallons per minute of flow but the steering function generally operates at pressure of 1500 to 2000 psig. The only modification needed to the tractor’s original hydraulic system is a higher displacement steering unit. This is because a rotary actuator requires more fluid to move the wheel through its entire range of motion than a cylinder does. The plumbing of the steering control unit is routed directed to the actuator, eliminating sections of hose and fittings otherwise required by the cylinder.
Height and orientation of the sprayer boom are also controlled with hydraulics. A five-spool solenoid valve routes hydraulic fluid to and from cylinders that raise, lower, rotate, and pivot the prayer boom. Furthermore, an open-center motor, controlled by an electronic flow-control valve, supplies the driving torque to apply the fertilizer or other substance to crops. The retrofit package also includes a suspension style swing arm fork with twin air springs capable of supporting loads to 8000 pounds above the front tire. The air springs’ pressure is adjustable for different loads for smooth riding in the roughest of field conditions. The manufacturer supplied an electric air compressor to generate the pneumatic power for raising pressure in the air springs. The fork’s open front allows for easy access for changing or repairing the front tire. The fork is 50 inches wide, allowing use of huge, 44.00-inch tires for the maximum flotation and the potential for ground pressure as low as four psig.
An integrated solution
The cutaway above shows initial position of piston and output shaft. Pressurized fluid entering the inlet port pushes on the piston; a stationary ring hear causes the piston to rotate clockwise. At right, teeth on the output shaft mesh with those on the ID of the piston, causing the shaft to rotate clockwise relative to the piston. Pressuring the B port returns the piston and shaft to their initial positions.
The actuator used for steering and load support is Parker’s Helac L30-65 actuator. This actuator not only provides a simpler, less expensive structure than alternative designs but also can generate the high torque needed to steer such a large wheel assembly under full load. Previously the manufacturer used steering cylinders, bearings and multiple joints before designing in the sliding spline actuator. With cylinders, all the external moving parts were exposed to the elements. The stress on the joins was high because each steering cylinder had a clevis pin at each end. Stress concentrated on each pin created high wear points, which increased maintenance. Worn pins also allowed side loads to be transmitted to the piston rod. This accelerated wear on the rod and piston bearings increased the occurrence of seal leakage.
A helical rotary actuator is ideal for this type of high torque application
The actuator used in the manufactuer's sprayer retrofit is composed of three basic parts: a housing, a central through shaft and an annular piston. Helical gear teeth on the shaft mesh with matching teeth on the inner circumference of the piston; a second set of helical teeth of opposite hand on the outer circumference of the piston engage the housing’s integral ring gear. The double helix gear design works to compound shaft rotation. The rotation of the shaft is almost twice that of the piston. The result is a slender, compact, symmetrical design that generates high torque, is highly tolerant of shock loads, and has none of the house protrusions found in alternative designs.
Characteristics of the helical rotary actuator make it ideal for applications requiring high torque within a small envelope, attributable, primarily, to its sliding-spline operation. Because all spline teeth remain engaged at all times, loads are equally distributed over the teeth. This results in high tolerance to the stock loads. Backlash is minimal – approximately 1°. Furthermore, the integral bearing design enables the actuator to support heavy radial, moment and thrust loads without the need for additional, external bearings. The integral bearing design also produces a clean, compact assembly for a wide variety of applications, including construction and mining equipment, refuse cart dumpers – anywhere compact size, high torque, and wide angle of rotation are needed. Aside from the inherent compact size of the actuator, the integral bearings and large drilled-and-tapped mounting holes make it easy to design the actuator info a structure and simplifies installation.
Benefits provide an edge
The manufacturer significantly benefited from switching to Parker’s Helac rotary actuators in three distinct ways:
Parker’s Helac actuators offer a compact package that provides all the support for the load as well as the hydraulic turning needs without adding unnecessary weight. Seal leakage is eliminated and there are fewer maintenance issues since all moving parts are safely enclosed in a cylindrical envelope. Visit www.parker.com/cylinder for more information about Parker’s various actuators.
Article contributed by Dan Morgado, applications engineer, Parker Hannifin's Cylinder Division.
Parker Chelsea’s Power Take-Off (PTO) is designed and built to meet the demands of the mobile equipment industry. The Chelsea PTO is intended to provide a long service life, both on-highway and off-highway. In order to maximize the life of Chelsea’s PTOs, it is important to have the PTO in proper use and constantly maintain the PTO as well.
The Chelsea PTO application worksheet and owner’s manual will help you properly specify your PTO and install it. However, the understanding of how a power shift PTO operates will help the troubleshooting process run more smoothly and effectively. For power shift operation, when a power shift PTO is engaged, a solenoid is energized. Air or hydraulic fluid then compresses a clutch pack in the PTO. This locks the PTO output gear to the output shaft and allows work to be done. When the power shift PTO is disengaged, the solenoid de-energizes. Air or hydraulic fluid deadheads against the valve. From there, air is released to atmosphere through a valve, and hydraulic fluid exhausts into the PTO.
Here are some breakdowns of the potential causes and solutions for troubleshooting the PTO. It is first important to understand that many problems from a Power Shift PTO are the result of incorrect plumbing. A good first procedural step can be found in the Owner’s Manual, which is to compare what pressure is coming from the air or hydraulic source against what pressure is entering the PTO.
Dealing with the PTO unit not engaging, these are some of the potential causes with solutions for shifting problems from Power Shift PTOs. (Probable causes are listed in a logical test sequence. Don’t assume any one thing is wrong.)
PTO unit engaging but not operating under system load
There are situations where the PTO will engage but may not operate under system load. Here are some potential causes and solutions for Power Shift PTOs.
An issue run into can be the relation between Power Shift PTOs and the solenoid valve. Here are some potential causes and solutions for Power Shift PTOs engaging without switching on the solenoid valve.
Potential shifting problems with Power Shift PTOs may lead to the PTO not disengaging. Here are some potential causes and solutions for Power Shift PTOs.
Electronic overspeed control operation
Chelsea has developed the next generation of Overspeed Controls for Power Shift PTOs. This system helps prevent the driver from going down the road with the PTO engaged and prevents the power take-off and driven equipment from being operated at excessive speeds. When the Electronic Overspeed Control Operation (EOC control) is changed to the “on” position, it energizes a solenoid valve that pressurizes the clutch pack. This then engages the PTO. A main feature of the EOC is the measuring of speed of the PTO electronically and uses that measurement in comparison to the selected overspeed RPM setting. If/when the PTO exceeds the preselected RPM setting, the EOC will de-energize the solenoid valve, disengaging the PTO. The PTO will remain disengaged until the speed has been reduced to the preselected reset speed. At that time, the PTO will re-engage.
It is a very simple set up with easy set-up buttons. LED lighting is outputted in three settings for great visibility in the EOC. When the PTO is in overspeed protection mode, audio and visual blinking overspeed warning alerts the operator. This system can be used in applications including LP Gas Trucks, Water Trucks, Fire and Rescue, Aerial Devices, Dump Truck & Trailers, Snow and Ice Removal. Learn more on our Electronic Overspeed Control product page.
This article was contributed by Michael Mabrouk, marketing leadership associate, Chelsea Products Division, Parker Hannifin Corporation.
A Power Take-Off, or PTO, gives a truck versatility beyond its usual function of providing transportation for materials. It directs power to the auxiliary equipment to perform work at the site and/or enroute. A PTO can eliminate the need for a second, or auxiliary, engine to power the equipment. Efficiency is gained through a PTO being applied to any form of vehicle transportation application including dump trucks, garbage trucks, snow trucks and many more.
Here are ten frequently asked questions to have a jumpstart in understanding how a PTO works and to aid your PTO learning process:Why is it called a power take-off?
A power take-off is a gearbox that directs power from the engine and transfers that power to auxiliary equipment through the rotation of the PTO gears and the vehicle transmission gears meshing. The power is generated from the truck’s engine power and is used to power the piece of equipment on the vehicle application.
PTOs are generally categorized by their mounting type. The three most common PTOs are side mount, rear mount, and top mount. Refer to previous blog post Understanding Why There are So Many Options for Mounting a PTO to read about the main mounting types available for a PTO.:
The speed of the PTO output is dependent on internal gearing of the PTO as well as the internal ratio of the transmission in relation to the PTO driver gear. For an automatic transmission, the minimum input speed higher than torque converter lock-up must be maintained for PTO operation (unless the transmission offers “live drive”, meaning the PTO is powered through the impeller). Depending on the internal gearing, PTO output speeds can be less than, greater, or equal to that of the transmission.
When specifying a PTO, we need to find the input horsepower required of the driven equipment. Horsepower is the measure of capacity for doing work per unit of time. Torque is the effort required to perform a twisting or turning motion. The horsepower is figured into the equation to find the torque requirements for the proper PTO to be used. Parker Chelsea categorizes product series using torque values.
The equation is: Torque (T) = HP x 5,252 / RPM
Parker Chelsea classifies PTO series as either intermittent or continuous. It is important to note that for an application that is “continuous” duty, (i.e. the PTO is in operation more than five minutes in any given 15-minute period), intermittent torque values must be de-rated by 30% unless the PTO is already classified as continuous duty.
Refer below to Parker Chelsea’s application catalog to help find the appropriate torque requirements of your application. All series are annotated as continuous or intermittent.
Do all trucks have a power take off provision (options)?
Power take-off provisions include special wiring and programming along with apertures on the vehicle’s transmission that allow for the mounting of the PTO. The “PTO ready” option needs to be ordered and configured at the chassis manufacturer when building out a work truck.
There are two major types of independent PTOs; mechanical (i.e. 489 series) and hydraulic (i.e. new 210 series). A hydraulic shift PTO uses a clutch mechanism for engagement. Hydraulic shift PTOs apply to traditional (torque converter) automatic transmissions. A mechanical shift PTO physically engages by shifting one gear into another. This is done typically through a lever, cable or air pressure. Mechanical shift PTOs apply to manual and automated manual transmissions.What are common terms used in PTO operations?
Spur gear: A gear whose teeth are cut straight across the face of the gear.
Helical gear: A gear whose teeth are cut on an angle diagonally across the gear either with a right or left-hand slant. For helical gears to mate, one must slant to the right and the other to the left.
Pitch line: The point on the gear tooth midway between the base of the tooth and the tip of the tooth.
Pitch line velocity: The speed of rotation in feet per minute of a gear measured at the pitch line.
Pitch (Gear): The measure of the size of the gear teeth determined by the number of teeth in a given area measured at the pitch line. PTO gear pitch is normally classified as 5, 6, or 7-pitch.
Gear ratio: It is determined by dividing the number of teeth in the driven gear by the number of teeth in the driving gear.
To specify a PTO, you will need to determine the tech specs needed for the application. Are there easy formulas to assist in the process?
What should be done for PTO maintenance on a daily and monthly timeframe?
It is very important to have periodic PTO maintenance for proper, safe, and trouble-free operation of the PTO. It is recommended to follow below the maintenance schedule.
Daily: Check all air, hydraulic and working mechanisms before operating the PTO. Perform maintenance as required.
Monthly: Inspect for possible leaks and tighten all air, hydraulic and mounting hardware, if necessary. Torque all bolts, nuts, etc. to Chelsea specifications. Ensure that splines are properly lubricated, if applicable. Perform maintenance as required.What is recommended for increasing hydraulic pump life when installed on a PTO?
A potential issue with a PTO can be premature spline fretting or wear caused by torsional vibrations. Traditionally, regular grease application between the PTO output and the PTO shafts is incorporated into the preventive maintenance schedule of the truck. This entails every two to three months having the pump removed from the PTO and having the mating shafts cleaned and regreased. Parker Chelsea provides spline lubrication grease with every PTO that has a pump mount option. They have also developed Wet Spline technology that helps provide a constant flow of fresh oil to the PTO and pump shafts to mitigate the issue of spline fretting and the wear which leads to not needing the maintenance inspections. Check out what Parker Chelsea offers for Wet Spline Technology and the additional benefits it provides.
To learn more about the PTOs and the product options offered, visit our website www.parker.com/chelsea.