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China Best Sales Friction Torque Limiter Ffv1-Ffv2 Series Pto Drive Shaft for Agricultural Machines Manufacturer OEM / ODM Auto Parts Tractor Transmission CZPT Limiter near me supplier

Product Description

Friction torque limiter FFV1-FFV2 Series PTO drive shaft for agricultural machines manufacturer OEM / ODM auto parts tractor transmission universal limiter

Caution!

Friction clutches may become hot during use.

Do not touch!

Keep the area around the friction clutch clear of any material which could catch fire and avoid prolonged slipping.

Main uses and guarantees:

NOTE: available CZPT for anti-clockwise direction of rotation.

The torque limiter is activated when the setting torque exceeds the calibration torque. During the torque CZPT limiting phase,the clutch continues to transmit power. The clutch is useful as a safety device to avoid load peaks and starting machines with high rotational inertia. It is recommended to ensure that the setting value is correct to avoid excessive heating of the friction discs (insufficient setting) or clutch seizing (excessive setting).

Extensive use for agricultural machines
Guarantee: High precision, high wear resistance, low noise, smooth and steady, high strength.

 

 

 

 

 

 

Choosing the Right Ball Bearing for Your Application

When choosing a Ball Bearing, there are several things to consider. These factors include: the size, lubricant type, presence of corrosive agents, stray electrical currents, and more. It can be challenging to choose the right type, size, and type of ball bearing for your application. You should also carefully calculate the loads to determine the right size. Here are some tips for choosing the right Ball Bearing for your application.

Single-row

The single-row ball bearing is 1 of the most popular types of bearings. The inner and outer ring are designed with raceway grooves that are shaped slightly larger than the balls. This type of bearing has a low torque and can handle high-speed applications with minimal power loss. The radial dimensions of single-row ball bearings also vary, so it is possible to find 1 that fits your specific application. Besides the above-mentioned advantages, single-row ball bearings are also available with varying grease levels and are widely applicable to applications where the space is limited.
Single-row ball bearings are also called angular-contact ball bearings. Because of their single-row design, they are not separable and can accommodate a high-speed, heavy-duty application. Single-row angular-contact ball bearings can only handle axial load in 1 direction, and they must be installed in pairs for pure radial loads. Single-row ball bearings are a popular type of rolling bearings and can be used for a wide range of applications.
bearing

Self-aligning

The self-aligning ball bearing was invented by Sven Wingquist, a plant engineer for a textile company in Sweden. While he was responsible for making production as efficient as possible, he soon realized that the machinery he had in place wasn’t working as efficiently as it could. Although ball bearings are great for reducing friction, they were not flexible enough to compensate for misalignments in the machine.
Self-aligning ball bearings have 2 rows of balls and a common sphered raceway. The inner ring is curved and combines the 2 rows of balls into 1 cage. These bearings can tolerate shaft misalignment and compensate for static angular defects. They can be used in simple woodworking machinery, ventilators, and conveying equipment. They are often the preferred choice for applications where shaft alignment is an issue.

Ceramic

A Ceramic ball bearing is a type of high-performance bearing that is available in both full-ceramic and hybrid forms. The main differences between ceramic and steel ball bearings are their construction, lubrication, and mobility. High-quality ceramic ball bearings are durable, and they are ideal for corrosive and high-temperature applications. The material used to create these bearings helps prevent electrolytic corrosion. They are also ideal for reducing the friction and lubrication requirements.
Ceramic balls are harder and less brittle than steel balls, which gives them a higher degree of rigidity. Ceramics also have a higher hardness, with a hardness of Rc75-80 compared to Rc58-64 for steel balls. Their high compressive strength is approximately 5 to 7 times greater than steel. In addition, they have a very low coefficient of friction, which allows them to spin at higher speeds and with less friction. This increases their lifespan and durability, and decreases the energy needed to turn cranks.

Steel

Unlike traditional bearings, steel balls have a relatively uniform hardness. Carbon steel, for instance, is 2.1% carbon by weight. According to the American Iron and Steel Institute, copper content must be no more than 0.40% and manganese content should not be more than 1.65 g/cm3. After carbonizing, steel balls undergo a process called sizing, which improves their roundness geometry and hardness.
The main differences between steel ball bearings and ceramic ball bearings can be traced to their different materials. Ceramic balls are made from zirconium dioxide or silicon nitride. Silicon nitride is harder than steel and resists shocks. The result is increased speed and longer service life. Polyoxymethylene acetal (PMMA) bearing balls are known for their stiffness, strength, and tolerance, but are not as common as steel ball bearings.

Plastic

The most popular types of plastic ball bearings are made of polypropylene or PTFE. These bearings are used in applications requiring higher chemical resistance. Polypropylene is a structural polymer that offers excellent physical and chemical properties, including excellent resistance to organic solvents and degreasing agents. Its lightweight, low moisture absorption rate, and good heat resistance make it an excellent choice for high-temperature applications. However, plastic bearings are not without their drawbacks, especially when operating at very high temperatures or under heavy loads.
Compared to metal bearings, plastic ball-bearings do not require lubrication. They also are highly corrosion-resistant, making them an excellent choice for wash-down applications. They are also post-, autoclave-, and gamma sterilizable. Many conventional steel ball-bearings cannot handle the high temperatures of food processing or swimming pools. In addition to high temperature applications, plastic ball bearings are resistant to chemicals, including chlorine.
bearing

Glass

Plastic sliding bearings are molded bearings made of engineering plastic. With self-lubricating modification technology, these bearings can be produced by injection molding of plastic beads. They are widely used in various industries such as office equipment, fitness and automotive equipment. In addition to plastic bearings, glass balls are used in a variety of other applications, including medical equipment. Glass ball bearings have excellent corrosion resistance, excellent mechanical properties, and are electrically insulators.
Plastic ball bearings are made of all-plastic races and cages. These bearings are suitable for applications that are exposed to acids and alkalis. Because they are cheaper than glass balls, plastic ball bearings are popular in chemical-exposed environments. Stainless steel balls are also resistant to heat and corrosion. But the main disadvantage of plastic ball bearings is that they are not as strong as glass balls. So, if weight and noise is your main concern, consider using plastic balls instead.

Miniature

The global miniature ball bearing market is expected to reach US$ 2.39 Billion by 2027, at a CAGR of 7.2%. Growth in the region is attributed to technological advancement and government initiatives. Countries such as India and China are attracting FDIs and emphasizing the establishment of a global manufacturing hub. This is boosting the market for miniature ball bearings. The miniscule ball bearings are manufactured in small quantities and are very small.
Some manufacturers produce miniature ball bearings in different materials and designs. Chrome steel is the most popular material for miniature ball bearings because of its high load capacity, low noise properties, and lower cost. But the cost of stainless steel miniature bearings is low, since the amount of steel used is minimal. Stainless steel miniature bearings are the smallest in size. Therefore, you can choose stainless steel mini ball bearings for high-speed applications.

Angular-contact

Angular-contact ball bearings have 3 components: a cage, inner ring, and balls. Angular-contact ball bearings can support high axial and radial loads. Various design and manufacturing attributes make angular-contact ball bearings suitable for a variety of applications. Some features of this bearing type include a special lubricant, different cage materials, and different coatings.
The size of an angular-contact ball bearing is determined by the design units: outer ring width, axial load, and radial load. Depending on the type of application, an angular-contact ball bearing may be manufactured in double-row, triple-row, or quadruple-row configurations. Angular contact ball bearings can be classified according to their design units, which range from metric to imperial. A higher ABEC number means tighter tolerances. To determine the tolerance equivalent of a particular bearing, consult a standard Angular-contact ball bearing table.
Angular-contact ball bearings feature high and low-shoulder configurations. They have two-dimensional races that accommodate axial and radial loads. They are available in self-retaining units with solid inner and outer rings, and ball and cage assemblies. Cages made of cast and wrought brass are the most popular, but lightweight phenolic cages are also available. The latter is a better choice because it doesn’t absorb oil and has lower rolling friction.
bearing

Materials

When it comes to the construction of a ball bearing, high-quality raw materials are a crucial component. These materials not only affect the overall quality of a ball bearing, but also influence the cost. That’s why you should pay close attention to raw material quality. In addition to that, raw materials should be tested several times before the manufacturing process to ensure quality. Read on for some information about the different types of materials used to make ball bearings.
Steel is the most common material for ball bearings. Most ball bearings contain stainless steel balls, which are remarkably corrosion-resistant. They are also resistant to saltwater and alkalis. However, stainless steel balls are heavier than plastic ones, and they are also magnetic, which may be a drawback in some applications. If you’re looking for a metal-free option, glass balls are the way to go. They’re sturdy, lightweight, and resistant to a wide range of chemicals.

China Best Sales Friction Torque Limiter Ffv1-Ffv2 Series Pto Drive Shaft for Agricultural Machines Manufacturer OEM / ODM Auto Parts Tractor Transmission CZPT Limiter     near me supplier China Best Sales Friction Torque Limiter Ffv1-Ffv2 Series Pto Drive Shaft for Agricultural Machines Manufacturer OEM / ODM Auto Parts Tractor Transmission CZPT Limiter     near me supplier

China high quality Tractor Parts Agricultural Pto Shaft Connect Parts Cardan Drive Shaft Yoke U Joint Front Splined Slip Yoke of CZPT Engine with Hot selling

Product Description

Tractor parts Agricultural Pto Shaft Connect Parts Cardan Drive shaft Yoke U Joint Front splined slip yoke Of CZPT Engine

Products Description

1.Forged high quality alloy steel cross is case hardened to provide good wear resistance and maximum service life. Pre-installed grease fitting in the cross saves time, prevents installation damage and allows for easy U-Joint maintenance.
2.Forged high strength steel cups are case hardened for strength and durability. Cup face and outer diameter are precision ground to provide precise fit, lock up and balance ability.
3.High carbon steel needle bearings are through hardened and precision ground using a optimized crowning profile for maximum life and load carrying capacity.
4.Seals are made out of high quality nitrile rubber for optimal grease retention and contaminant exclusion. Multi-lip seal is pliable, yet tough and tear resistant.
5.All U-Joints are pre-lubricated with a premium, high temperature grease that performs well in a wide temperature range and provides a long service life.

 

 

 

Company Profile

How to Compare Different Types of Spur Gears

When comparing different types of spur gears, there are several important considerations to take into account. The main considerations include the following: Common applications, Pitch diameter, and Addendum circle. Here we will look at each of these factors in more detail. This article will help you understand what each type of spur gear can do for you. Whether you’re looking to power an electric motor or a construction machine, the right gear for the job will make the job easier and save you money in the long run.
Gear

Common applications

Among its many applications, a spur gear is widely used in airplanes, trains, and bicycles. It is also used in ball mills and crushers. Its high speed-low torque capabilities make it ideal for a variety of applications, including industrial machines. The following are some of the common uses for spur gears. Listed below are some of the most common types. While spur gears are generally quiet, they do have their limitations.
A spur gear transmission can be external or auxiliary. These units are supported by front and rear casings. They transmit drive to the accessory units, which in turn move the machine. The drive speed is typically between 5000 and 6000 rpm or 20,000 rpm for centrifugal breathers. For this reason, spur gears are typically used in large machinery. To learn more about spur gears, watch the following video.
The pitch diameter and diametral pitch of spur gears are important parameters. A diametral pitch, or ratio of teeth to pitch diameter, is important in determining the center distance between 2 spur gears. The center distance between 2 spur gears is calculated by adding the radius of each pitch circle. The addendum, or tooth profile, is the height by which a tooth projects above the pitch circle. Besides pitch, the center distance between 2 spur gears is measured in terms of the distance between their centers.
Another important feature of a spur gear is its low speed capability. It can produce great power even at low speeds. However, if noise control is not a priority, a helical gear is preferable. Helical gears, on the other hand, have teeth arranged in the opposite direction of the axis, making them quieter. However, when considering the noise level, a helical gear will work better in low-speed situations.

Construction

The construction of spur gear begins with the cutting of the gear blank. The gear blank is made of a pie-shaped billet and can vary in size, shape, and weight. The cutting process requires the use of dies to create the correct gear geometry. The gear blank is then fed slowly into the screw machine until it has the desired shape and size. A steel gear blank, called a spur gear billet, is used in the manufacturing process.
A spur gear consists of 2 parts: a centre bore and a pilot hole. The addendum is the circle that runs along the outermost points of a spur gear’s teeth. The root diameter is the diameter at the base of the tooth space. The plane tangent to the pitch surface is called the pressure angle. The total diameter of a spur gear is equal to the addendum plus the dedendum.
The pitch circle is a circle formed by a series of teeth and a diametrical division of each tooth. The pitch circle defines the distance between 2 meshed gears. The center distance is the distance between the gears. The pitch circle diameter is a crucial factor in determining center distances between 2 mating spur gears. The center distance is calculated by adding the radius of each gear’s pitch circle. The dedendum is the height of a tooth above the pitch circle.
Other considerations in the design process include the material used for construction, surface treatments, and number of teeth. In some cases, a standard off-the-shelf gear is the most appropriate choice. It will meet your application needs and be a cheaper alternative. The gear will not last for long if it is not lubricated properly. There are a number of different ways to lubricate a spur gear, including hydrodynamic journal bearings and self-contained gears.
Gear

Addendum circle

The pitch diameter and addendum circle are 2 important dimensions of a spur gear. These diameters are the overall diameter of the gear and the pitch circle is the circle centered around the root of the gear’s tooth spaces. The addendum factor is a function of the pitch circle and the addendum value, which is the radial distance between the top of the gear tooth and the pitch circle of the mating gear.
The pitch surface is the right-hand side of the pitch circle, while the root circle defines the space between the 2 gear tooth sides. The dedendum is the distance between the top of the gear tooth and the pitch circle, and the pitch diameter and addendum circle are the 2 radial distances between these 2 circles. The difference between the pitch surface and the addendum circle is known as the clearance.
The number of teeth in the spur gear must not be less than 16 when the pressure angle is 20 degrees. However, a gear with 16 teeth can still be used if its strength and contact ratio are within design limits. In addition, undercutting can be prevented by profile shifting and addendum modification. However, it is also possible to reduce the addendum length through the use of a positive correction. However, it is important to note that undercutting can happen in spur gears with a negative addendum circle.
Another important aspect of a spur gear is its meshing. Because of this, a standard spur gear will have a meshing reference circle called a Pitch Circle. The center distance, on the other hand, is the distance between the center shafts of the 2 gears. It is important to understand the basic terminology involved with the gear system before beginning a calculation. Despite this, it is essential to remember that it is possible to make a spur gear mesh using the same reference circle.

Pitch diameter

To determine the pitch diameter of a spur gear, the type of drive, the type of driver, and the type of driven machine should be specified. The proposed diametral pitch value is also defined. The smaller the pitch diameter, the less contact stress on the pinion and the longer the service life. Spur gears are made using simpler processes than other types of gears. The pitch diameter of a spur gear is important because it determines its pressure angle, the working depth, and the whole depth.
The ratio of the pitch diameter and the number of teeth is called the DIAMETRAL PITCH. The teeth are measured in the axial plane. The FILLET RADIUS is the curve that forms at the base of the gear tooth. The FULL DEPTH TEETH are the ones with the working depth equal to 2.000 divided by the normal diametral pitch. The hub diameter is the outside diameter of the hub. The hub projection is the distance the hub extends beyond the gear face.
A metric spur gear is typically specified with a Diametral Pitch. This is the number of teeth per inch of the pitch circle diameter. It is generally measured in inverse inches. The normal plane intersects the tooth surface at the point where the pitch is specified. In a helical gear, this line is perpendicular to the pitch cylinder. In addition, the pitch cylinder is normally normal to the helix on the outside.
The pitch diameter of a spur gear is typically specified in millimeters or inches. A keyway is a machined groove on the shaft that fits the key into the shaft’s keyway. In the normal plane, the pitch is specified in inches. Involute pitch, or diametral pitch, is the ratio of teeth per inch of diameter. While this may seem complicated, it’s an important measurement to understand the pitch of a spur gear.
gear

Material

The main advantage of a spur gear is its ability to reduce the bending stress at the tooth no matter the load. A typical spur gear has a face width of 20 mm and will fail when subjected to 3000 N. This is far more than the yield strength of the material. Here is a look at the material properties of a spur gear. Its strength depends on its material properties. To find out what spur gear material best suits your machine, follow the following steps.
The most common material used for spur gears is steel. There are different kinds of steel, including ductile iron and stainless steel. S45C steel is the most common steel and has a 0.45% carbon content. This type of steel is easily obtainable and is used for the production of helical, spur, and worm gears. Its corrosion resistance makes it a popular material for spur gears. Here are some advantages and disadvantages of steel.
A spur gear is made of metal, plastic, or a combination of these materials. The main advantage of metal spur gears is their strength to weight ratio. It is about 1 third lighter than steel and resists corrosion. While aluminum is more expensive than steel and stainless steel, it is also easier to machine. Its design makes it easy to customize for the application. Its versatility allows it to be used in virtually every application. So, if you have a specific need, you can easily find a spur gear that fits your needs.
The design of a spur gear greatly influences its performance. Therefore, it is vital to choose the right material and measure the exact dimensions. Apart from being important for performance, dimensional measurements are also important for quality and reliability. Hence, it is essential for professionals in the industry to be familiar with the terms used to describe the materials and parts of a gear. In addition to these, it is essential to have a good understanding of the material and the dimensional measurements of a gear to ensure that production and purchase orders are accurate.

China high quality Tractor Parts Agricultural Pto Shaft Connect Parts Cardan Drive Shaft Yoke U Joint Front Splined Slip Yoke of CZPT Engine     with Hot sellingChina high quality Tractor Parts Agricultural Pto Shaft Connect Parts Cardan Drive Shaft Yoke U Joint Front Splined Slip Yoke of CZPT Engine     with Hot selling

China Hot selling hollow shaft stepper motor cardan pto drive shaft Tractor PTO Shaft wholesaler

Situation: New
Warranty: 6 Months
Applicable Industries: Creating Content Shops, Producing Plant, Machinery Repair Shops, Farms, Retail, Building works , Energy & Mining
Showroom Area: None
Online video outgoing-inspection: Provided
Equipment Examination Report: Offered
Marketing and advertising Variety: Normal Product
Sort: Shafts
Use: Harvesters
Tractor Shaft: Agriculture Shaft
cardan pto travel shaft: drive shaft
hollow shaft stepper motor: equipment shaft
Package deal: Carton
After Warranty Services: On the internet help
Neighborhood Service Location: None
Packaging Details: Cartons or pallets
Port: ZheJiang or HangZhou Port

Hollow shaft stepper motor Cardan PTO Drive Shaft PTO drive shaft for various brand names of agriculture equipment, such as tractor Johndeer, situation, A4AF3 A4BF3 Automatic Transmission Gearbox Overhaul package Seal Kit for HYUNDAI KIA ZG5713004 and newholland

Sort: T571 1″3/8 Z6
Materials: 20Cr or 20CrMnTi
Floor Hardness: fifty eight-64HRC
Core hardness:20Cr: 25-45HRC / 20CrMiTi: 33-48HRC

Packaging & Shipping
Packaging Information: Cartons or pallets
Delivery Depth: 45-50days
Specifications

Device PTO shaft
one) MOQ:50 sets
2) CE Certification
three) Sophisticated equipment

Firm Information
We are factories specialised in producing Tractor PTO Shaft, PTO Spare Areas with virtually twenty many years. Our handbook manufacturing quantity is far more than 6000,000,000 sets. ISO9001 & CE are our good quality certifications.

Market and Trade Integration
With CE certificate
Diverse Types of U-Joint employed in the PTO Shaft
Forged yoke
Use for 15-120HP
Multitooth spline. Technical specs from the 1 3 / 8 “Z6, 1 1 / 8” Z6, 1 3 / 4 “Z6, 1 3 / 8” Z20, Vehicle Component Transmission Propeller Travel Shaft For CZPT Alphard Vellfire 2009 1 1 / 8 “Z20, 1 3 / 4” Z20, 1 3 / 8 “Z21 , 1 1 / 8 “Z21, 1 3 / 4” Z21, etc., full requirements are welcome.
FAQFor much more details about us, make contact with us correct absent.
We will do our best to meet up with your requrement of the merchandise and offer the most perfected soon after-revenue providers for you.

Feel free to get a closer seem around our webpages, and if you have interested in, new engine bracket rubber bushing 18 0571 18571 18571 9639176847 180921 for Peugeot 206 307 308 406 407 607 CitroenC4 C5 make sure you enquiry to us your favorite things.welcome you link with us or come to our factory to make order with sample for the great develepment of our distribution.

Travel shaft type

The driveshaft transfers torque from the motor to the wheels and is dependable for the clean managing of the vehicle. Its design experienced to compensate for differences in size and angle. It have to also make certain best synchronization amongst its joints. The travel shaft need to be made of higher-grade resources to obtain the very best equilibrium of stiffness and elasticity. There are 3 primary kinds of generate shafts. These incorporate: end yokes, tube yokes and tapered shafts.
air-compressor

tube yoke

Tube yokes are shaft assemblies that use metallic components as the primary structural element. The yoke involves a uniform, considerably uniform wall thickness, a very first stop and an axially extending 2nd end. The first diameter of the generate shaft is better than the 2nd diameter, and the yoke further includes a pair of opposing lugs extending from the 2nd stop. These lugs have holes at the finishes for attaching the axle to the vehicle.
By retrofitting the driveshaft tube finish into a tube fork with seat. This valve seat transmits torque to the driveshaft tube. The fillet weld 28 boosts the torque transfer capacity of the tube yoke. The yoke is typically made of aluminum alloy or metal substance. It is also utilized to link the generate shaft to the yoke. Various designs are achievable.
The QU40866 tube yoke is employed with an exterior snap ring type common joint. It has a cup diameter of 1-3/sixteen” and an total width of 4½”. U-bolt kits are one more alternative. It has threaded legs and locks to aid safe the yoke to the push shaft. Some performance automobiles and off-street vehicles use U-bolts. Yokes must be machined to settle for U-bolts, and U-bolt kits are frequently the preferred accessory.
The finish yoke is the mechanical element that connects the push shaft to the stub shaft. These yokes are normally developed for distinct drivetrain components and can be personalized to your wants. Pat’s drivetrain delivers OEM substitute and custom flanged yokes.
If your tractor uses PTO elements, the cross and bearing package is the excellent resource to make the link. Furthermore, cross and bearing kits assist you match the appropriate yoke to the shaft. When picking a yoke, be certain to evaluate the outside the house diameter of the U-joint cap and the inside of diameter of the yoke ears. After using the measurements, check with the cross and bearing identification drawings to make positive they match.
While tube yokes are normally straightforward to replace, the greatest outcomes appear from a certified device shop. Devoted driveshaft professionals can assemble and stability finished driveshafts. If you are not sure of a certain aspect, make sure you refer to the TM3000 Driveshaft and Cardan Joint Service Guide for far more details. You can also consult an excerpt from the TSB3510 manual for information on angle, vibration and runout.
The sliding fork is another essential component of the push shaft. It can bend in excess of rough terrain, allowing the U-joint to hold spinning in harder conditions. If the slip yoke fails, you will not be ready to push and will clang. You want to change it as shortly as feasible to stay away from any dangerous driving problems. So if you notice any dings, be sure to verify the yoke.
If you detect any vibrations, the drivetrain could need adjustment. It truly is a basic approach. First, rotate the driveshaft until finally you locate the correct alignment between the tube yoke and the sliding yoke of the rear differential. If there is no apparent vibration, you can wait for a while to solve the difficulty. Keep in thoughts that it may possibly be convenient to postpone repairs briefly, but it might trigger greater issues afterwards.
air-compressor

end yoke

If your driveshaft calls for a new conclude yoke, CZPT has several drivetrain alternatives. Our automotive finish yoke stock contains keyed and non-keyed choices. If you need to have tapered or straight holes, we can also make them for you.
A U-bolt is an industrial fastener that has U-shaped threads on its legs. They are usually employed to sign up for two heads back again to back again. These are handy possibilities to assist preserve drivetrain factors in spot when driving above rough terrain, and are generally compatible with a range of models. U-bolts require a specially machined yoke to accept them, so be sure to get the correct dimensions.
The sliding fork aids transfer electrical power from the transfer scenario to the driveshaft. They slide in and out of the transfer circumstance, allowing the u-joint to rotate. Sliding yokes or “slips” can be bought independently. Regardless of whether you want a new one or just a number of parts to up grade your driveshaft, 4 CZPT Parts will have the components you require to repair your vehicle.
The stop yoke is a necessary element of the drive shaft. It connects the generate practice and the mating flange. They are also utilised in auxiliary power equipment. CZPT’s drivetrains are stocked with a range of flanged yokes for OEM purposes and custom made builds. You can also locate flanged yokes for continuous velocity joints in our substantial stock. If you do not want to modify your current drivetrain, we can even make a custom made yoke for you.

China Hot selling hollow shaft stepper motor cardan pto drive shaft Tractor PTO Shaft  wholesaler China Hot selling hollow shaft stepper motor cardan pto drive shaft Tractor PTO Shaft  wholesaler