Power takeoff transmission mechanism

Abstract

The utility model discloses a power takeoff transmission mechanism, which solves the problems of high assembly difficulty, complex gear engaging control structure, insufficient large torque bearing capacity of a driving gear bearing support and lower fatigue life index, and comprises a power takeoff shell, an input shaft, an output shaft and a piston shaft, a driving gear is arranged on the input shaft, the driving gear is supported by a first bearing, and a bearing spacer bush is arranged between the first bearing and the input shaft; a gear shifting gear sleeve and a driven gear meshed with the driving gear are arranged on the output shaft; a gear shifting fork is arranged on the piston shaft, and the gear shifting fork is connected with the gear shifting gear sleeve. The gear engaging control structure is simple, the assembly difficulty is low, the driving gear is supported by the densely-arranged large-diameter needle bearings, larger torque can be borne, the fatigue life index is improved, and the service life of the power takeoff is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of transmission power take-offs, and specifically provides a power take-off transmission mechanism. Background Art

[0002] A power take-off is a power transmission component that transmits the power of an automobile engine or electric motor to the driving equipment of a special vehicle through mechanical transmission, thus realizing the unique functions of a special vehicle. A power take-off is generally installed at the side or rear end of a transmission. A full-power power take-off is installed between the engine and the transmission. The driving gear inside the power take-off drives the output shaft to rotate, and power transmission or termination is realized through the shifting and disengaging mechanism. It is widely used in special vehicles such as dump trucks, watering trucks, cement mixers, or other special vehicles.

[0003] At present, the mainstream structure of the power take-off driving gear bearing support assembly is to set two tapered roller bearings between the input shaft and the driving gear. The driving gear is supported by the two tapered roller bearings. The semicircular wear pads on both sides of the driving gear are radially limited by bolts screwed into the outside of the power take-off housing. In addition, the gear shifting mode of the power take-off is bidirectional gas operation, and two control valves are required to control the forward and reverse airflows respectively, so as to realize the gear shifting and disengaging of the power take-off.

[0004] However, the installation process of bearings and wear pads is relatively complicated, resulting in greater difficulty in assembly and lower efficiency. In addition, the control system structure of the two-way gas-operated system is relatively complex, the mechanical size is relatively large and the cost is high, resulting in the power take-off being too close to the vehicle frame or the oil and gas circuits being difficult to arrange, making it impossible to match the power take-off and the scope of use is not wide enough. In addition, since the active gear bearing support of the power take-off is not able to withstand large torque, poor heat dissipation under continuous high-load conditions causes internal overheating of the bearing, and the low fatigue life index of the bearing causes rapid fatigue failure of the bearing under continuous high loads, resulting in early damage to the active gear bearing support of the power take-off, causing the active gear to swing, large changes in the meshing center distance, unstable meshing of the gear pair, and severe overload of the gear teeth. The power take-off makes abnormal noises until the gear teeth break and fail. Utility Model Content

[0005] In order to solve the problems of difficult assembly of the power take-off, complex gear shifting control structure, insufficient ability of the active gear bearing support to withstand large torque, poor heat dissipation and low bearing fatigue life index, the utility model provides a power take-off transmission mechanism, which adopts closely-packed large-diameter needle roller bearings to support the active gear on the input shaft, so that the active gear supporting bearing can withstand greater torque, improve the fatigue life index and extend the life of the power take-off; there are sufficient gaps between the needle rollers for lubricating oil flow, so that the thermal management of the transmission system can be effectively controlled; and the wear pads and bearings adopted are easy to install, which can improve the assembly efficiency and the gear shifting control structure is simple.

[0006] The specific scheme of the utility model is as follows.

[0007] A power take-off transmission mechanism comprises a power take-off housing and an input shaft and an output shaft located inside the power take-off housing, wherein the input shaft is provided with a driving gear supported by a first bearing, and a bearing spacer is provided between the first bearing and the input shaft; the output shaft is provided with a shifting sleeve and a driven gear meshing with the driving gear; a piston shaft is also provided inside the power take-off housing, a shifting fork is provided on the piston shaft, and the shifting fork is connected to the shifting sleeve.

[0008] The bearing spacer sleeve is sleeved on the input shaft, the inner wall is in contact with the input shaft, and the outer wall is in contact with the first bearing. The utility model can withstand a large torque through the selection of the first bearing and the cooperation with the bearing spacer sleeve to support the driving gear, and the assembly difficulty is low, the assembly efficiency is improved, and the gear control structure adopted is simple, which reduces the cost and has a wider range of applications.

[0009] Preferably, the first bearing comprises an inner ring and an outer ring and a plurality of cylindrical rollers located in the annular space between the inner ring and the outer ring; the cross-sections at both ends of the first bearing are aligned with the cross-sections at both ends of the bearing spacer. The cross-sections at both ends of the first bearing are aligned with the cross-sections at both ends of the bearing spacer and the cross-sections at both ends of the driving gear, and fit with the wear pad.

[0010] Preferably, the roller diameter is between 6 mm and 8 mm, which is a preferred embodiment of the utility model. While enabling the first bearing to withstand a larger torque, it is also suitable for supporting the driving gear of the power take-off.

[0011] Preferably, the radial clearance between the plurality of rollers is between 0.04 mm and 0.08 mm, so that the first bearing can withstand greater torque. At the same time, the first bearing is a closely packed large-diameter needle roller bearing, and there are sufficient gaps between the rollers for lubricating oil to flow, so the heat dissipation capacity is stronger, so that the thermal management of the transmission system is effectively controlled.

[0012] Preferably, a wear pad is provided at each end of the bearing spacer: the wear pad is in an annular shape, is sleeved on the input shaft, and its edge is flush with the edge of the hub of the driving gear. The wear pad separates the bearing spacer, the closely spaced large-diameter needle bearing, the gear hub of the driving gear, etc. from the power take-off housing, thereby reducing wear.

[0013] One end of the wear pad is provided with a notch, the edge of the notch is a plane, and a raised step is provided at the corresponding position of the power take-off housing, and the notch of the wear pad fits with the raised step of the power take-off housing. The flat end of the wear pad is pressed against the raised step of the power take-off housing to prevent the wear pad from radial rotation. Compared with the current semicircular wear pads on both sides of the power take-off driving gear that are radially limited by screwing bolts from the outside of the power take-off housing, the wear pad structure adopted by the utility model is simpler, the assembly difficulty is low, and the assembly efficiency can be improved.

[0014] Preferably, the wear pad is made of a wear-resistant material bearing steel, and the bearing steel is GCr15 bearing steel, thereby reducing the wear of the wear pad.

[0015] Preferably, an elastic cylindrical pin is further provided on the input shaft, the input shaft is provided with a through hole perpendicular to the axial direction, the power take-off housing is provided with a through hole at a corresponding position, one end of the elastic cylindrical pin is embedded in the through hole on the input shaft, and the other end is embedded in the through hole on the power take-off housing. The elastic cylindrical pin connects the input shaft and the power take-off housing, avoiding radial rotation and axial movement of the input shaft, and also plays a role in shock absorption and buffering.

[0016] Preferably, a return spring is provided on the piston shaft. The return spring is sleeved on the piston shaft, one end of which is connected to the shift fork, and the other end is connected to the power take-off housing at the rear end of the piston shaft, that is, one end of the return spring is pressed against the shift fork, and the other end is pressed against the power take-off housing. When the shift fork is subjected to force, it moves and compresses the return spring. When the shift fork is not subjected to force, the return spring pushes the shift fork to return to its original position.

[0017] A cylinder head is also provided on the power take-off housing at the head end of the piston shaft, and a pneumatic joint is provided on the cylinder head. The pneumatic joint is located on the axis of the piston shaft, and the shift fork is fixed on the piston shaft. A sealed space is provided between the tail end of the piston shaft and the power take-off housing. The pneumatic joint is a compressed air inlet. When the compressed air enters the power take-off from the pneumatic joint, it pushes the piston shaft. The air in the sealed space at the tail end of the piston shaft is compressed, and the piston shaft moves. The shift fork fixed on the piston shaft compresses the reset spring, and the movement of the shift fork drives the connected shift gear sleeve to move.

[0018] Preferably, a shift signal switch is further provided on the power take-off housing, and the shift fork is provided with an inclined surface at a position corresponding to the shift signal switch. When the shift fork is in the original position, the inclined surface does not contact the shift signal switch, and the shift signal switch is in the disconnected state, indicating that the power take-off is in the neutral state; when the shift fork moves, the inclined surface contacts and squeezes the shift signal switch, and the shift signal switch is triggered, indicating that the power take-off is in the engaged gear state.

[0019] Preferably, the output shaft is supported by a pair of deep groove ball bearings, and the driven gear is supported by a needle bearing. The driven gear cannot directly drive the output shaft to rotate, that is, the driven gear cannot directly transmit power to the output shaft.

[0020] The utility model has the following beneficial effects.

[0021] By using closely packed large diameter needle roller bearings to support the driving gear on the input shaft, the driving gear supporting bearing can withstand greater torque. There are also sufficient gaps between the needle rollers for lubricating oil flow, which can enhance the heat dissipation capacity of the bearing and effectively control the thermal management of the transmission system.

[0022] The fatigue life index is improved. Compared with tapered roller bearings, the fatigue life is higher. Under the same application torque, it can work for a long time. Its strength is more reliable and its performance is more stable, thereby extending the life of the power take-off. It can meet the continuous high-load operating conditions of special vehicles such as high-pressure sprinkler trucks, cement mixer trucks, agricultural mobile multi-functional work vehicles, and is also suitable for the power take-off of the vehicle gearbox to work for a long time.

[0023] The driving gear support structure such as the wear pad and the bearing is simple, which reduces the assembly difficulty and improves the assembly efficiency. The gear control structure is simple, which reduces the cost and has a wider application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are merely embodiments of the present invention, and ordinary technicians in this field can obtain other drawings based on the provided drawings without creative work.

[0025] Figure 1 The utility model is a structural cross-sectional view of a power take-off transmission mechanism.

[0026] Figure 2 It is a cross-sectional view of the driving gear bearing support structure of the utility model.

[0027] Figure 3 It is a structural cross-sectional view of the wear pad of the utility model.

[0028] In the figure: power take-off housing 1, piston shaft 2, output shaft 3, input shaft 4, shift fork 5, return spring 6, pneumatic joint 7, cylinder head 8, shift signal switch 9, driven gear 10, shift gear sleeve 11, shift gear hub 12, deep groove ball bearing 13, needle roller bearing 14, driving gear 15, close-packed large diameter needle roller bearing 16, bearing spacer 17, wear pad 18, elastic cylindrical pin 19, raised step 20, needle roller 21. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] like Figure 1 The figure shows a structural cross-sectional view of a power take-off transmission mechanism of the utility model. The power take-off includes a power take-off housing 1 and an input shaft 4, an output shaft 3 and a piston shaft 2 located inside the power take-off housing 1. The input shaft 4 is located at the lower end of the power take-off housing 1, the output shaft 3 is located in the middle of the power take-off housing 1, and the piston shaft 2 is located at the upper end of the power take-off housing 1.

[0031] The piston shaft 2 is sleeved with a shift fork 5, which is fixedly mounted on the piston shaft 2. A return spring 6 is also provided on the piston shaft 2, one end of the return spring 6 is connected to the shift fork 5, and the other end is connected to the power take-off housing 1 at the rear end of the piston shaft 2, that is, one end of the return spring 6 presses on the shift fork 5, and the other end presses on the power take-off housing 1. When the shift fork 5 is subjected to force, it moves and compresses the return spring 6, and when the shift fork 5 is not subjected to force, the return spring 6 pushes the shift fork 5 to return to its original position.

[0032] A sealed space is provided between the rear end of the piston shaft 2 and the power take-off housing 1, that is, the rear end of the piston shaft does not contact the power take-off housing, and a certain distance is provided in the middle. Conical depressions are provided at both ends of the piston shaft 2, and the conical depression at the rear end of the piston shaft is connected with the closed space at the rear end. A cylinder head 8 is installed on the power take-off housing 1 at the front end of the piston shaft, and a pneumatic joint 7 is provided on the cylinder head 8. The pneumatic joint 7 is a compressed air inlet, which is connected with the conical depression at the front end of the piston shaft 2. When the compressed air enters the power take-off from the pneumatic joint 7, it pushes the piston shaft 2, and the air in the closed space at the rear end of the piston shaft is compressed, the piston shaft 2 moves, and the shift fork 5 fixed on the piston shaft 2 compresses the return spring 6.

[0033] A shift signal switch 9 is provided at the top of the power take-off housing 1, and a shift fork 5 is provided with an inclined surface at a position corresponding to the shift signal switch 9. When the shift fork 5 is in the original position, the inclined surface does not contact the shift signal switch 9, and the shift signal switch 9 is in the disconnected state, indicating that the power take-off is in the neutral state; when the shift fork 5 moves, the inclined surface contacts and squeezes the shift signal switch 9, and the shift signal switch 9 is triggered, indicating that the power take-off is in the engaged gear state.

[0034] The output shaft 3 is provided with a driven gear 10, which is supported by a needle bearing 14 sleeved on the output shaft 3. The input shaft 4 is provided with a driving gear 15, and the driven gear 10 on the output shaft meshes with the driving gear 15 on the input shaft, that is, the driven gear 10 on the output shaft rotates with the driving gear 15 on the input shaft. When the power take-off is in a neutral state, the output shaft 3 does not rotate with the driven gear 10, that is, the driven gear 10 is sleeved on the output shaft 3 without any gear.

[0035] The output shaft 3 is also provided with a shift gear sleeve 11, which is connected to the shift fork 5 on the piston shaft. When the shift fork 5 on the piston shaft moves, the shift gear sleeve 11 on the output shaft moves with the shift fork 5. The output shaft 3 is also provided with a shift gear hub 12, which is provided with an external spline. The inner hole of the shift gear hub 12 is provided with an external spline. Through the combination of the internal spline and the external spline, the shift gear hub 12 is fixedly mounted on the output shaft 3, and the output shaft 3 rotates with the shift gear hub 12. The parameters of the external spline of the shift gear hub 12 and the spline of the driven gear coupling tooth are consistent. When the power take-off is in the gear-engaging state, the shift gear sleeve 11 moves to the right, and the driven gear coupling tooth is coupled with the external spline of the shift gear hub. At this time, the driven gear 10 is coupled to the output shaft 3 through the shift gear sleeve 11 and the shift gear hub 12, and the output shaft 3 rotates with the driven gear 10, that is, the power is transmitted from the driven gear 10 to the output shaft 3.

[0036] The end of the output shaft 3 is also provided with an oil seal assembly, which is fixedly mounted at the end of the output shaft 3 and connected to the oil pump at the power take-off housing at the end of the output shaft 3. The output shaft 3 is supported by a pair of 6207 deep groove ball bearings 13, one of which is located at the front end of the oil seal assembly, and the other is located at the head end of the output shaft 3. A bearing cover plate is also provided on the outer side of the deep groove ball bearing 13.

[0037] The input shaft 4 is provided with a driving gear 15, which is supported by a needle bearing 16 sleeved on the input shaft 4. The needle bearing is a closely packed large-diameter needle bearing 16. A bearing spacer 17 is provided between the needle bearing 16 and the input shaft 4. The inner hole of the bearing spacer 17 fits with the input shaft 4, and the outer wall fits with the inner hole of the needle bearing 16. The interfaces of the two ends of the bearing spacer 17, the needle bearing 16 and the gear hub of the driving gear 15 are aligned. The driving gear 15 is sleeved on the input shaft 4 through the needle bearing 16 and the bearing spacer 17. The input shaft 4 does not rotate with the driving gear 15, that is, the driving gear 15 is sleeved on the input shaft 4 without any rotation.

[0038] A wear pad 18 is provided at each end of the bearing spacer 17. The wear pad 18 is in the shape of a circular ring and is sleeved on the input shaft 4. The wear pad 18 separates the bearing spacer 17, the closely spaced large-diameter needle bearing 16, and the gear hub of the driving gear 15 from the power take-off housing 1, thereby reducing wear. A notch is provided at one end of the wear pad 18, and the edge of the notch is a plane. A raised step 20 is provided at the corresponding position of the power take-off housing 1, and the notch of the wear pad 18 fits with the raised step 20 of the power take-off housing. The flat end of the wear pad 18 is pressed against the raised step 20 of the power take-off housing to prevent the wear pad 18 from rotating radially. The wear pad 18 is made of wear-resistant bearing steel, and this embodiment uses GCr15 bearing steel.

[0039] An elastic cylindrical pin 19 is also provided on the input shaft 4. A through hole is provided on the input shaft 4 perpendicular to the axial direction. A through hole is provided at a corresponding position of the power take-off housing 1. One end of the elastic cylindrical pin 19 is embedded in the through hole on the input shaft 4, and the other end is embedded in the through hole on the power take-off housing. The elastic cylindrical pin 19 connects the input shaft 4 and the power take-off housing 1, avoiding radial rotation and axial movement of the input shaft 4, and also plays a role in shock absorption and buffering.

[0040] like Figure 2 The figure shows a cross-sectional view of the driving gear bearing support structure of the utility model. In this embodiment, the diameter of the power take-off input shaft 4 is 20 mm, and the diameter of the close-packed large-diameter needle roller bearing 16 is 42 mm. In the close-packed large-diameter needle roller bearing, the needle rollers are closely arranged, thereby increasing the number of needle rollers per unit volume and improving the bearing capacity. The close-packed large-diameter needle roller bearing 16 in this embodiment is provided with 18 needle rollers 21. The needle roller diameter of the utility model is between 6 mm and 8 mm, which can withstand a larger load and has higher rigidity. The diameter of the needle roller 21 used in this embodiment is 6.214 mm, and the radial clearance between the needle rollers 21 is between 0.04 mm and 0.08 mm. There is enough gap between the needle rollers 21 for the flow of lubricating oil, which can enhance the heat dissipation capacity of the bearing and effectively control the thermal management of the transmission system. The diameter of the wear pad 18 used in this embodiment is 54 mm.

[0041] The transmission mechanism of the power take-off device of the utility model adopts closely packed large diameter needle roller bearings 16 to support the driving gear 15 on the input shaft 4, so that the bearing supporting the driving gear 15 can bear greater torque. There are also sufficient gaps between the needle rollers for lubricating oil flow, which can enhance the heat dissipation capacity of the bearing and effectively control the thermal management of the transmission system.

[0042] The power take-off assembly of this embodiment has been subjected to an indoor bench fatigue life endurance test, and its fatigue life index has been improved by about 50% compared with that before the improvement, exceeding the evaluation index of the QC / T319 industry standard. Under the same application torque, it can work for a long time, and its strength is more reliable and its performance is more stable, thereby extending the life of the power take-off, and can meet the continuous high-load use conditions of special vehicles such as high-pressure sprinklers, cement mixers, and agricultural mobile multi-functional working vehicles. It is also suitable for the power take-off of the vehicle gearbox to work for a long time. In addition, it has the characteristics of easy installation, which can improve assembly efficiency and is suitable for mass production.

[0043] like Figure 3 The structure cross-sectional view of the wear pad of the utility model is shown. The wear pad of the utility model is provided with two ring-shaped wear pads, and a notch is provided at the position where the raised step 20 of the power take-off housing is fitted, and the edge of the notch is a plane. The plane end of the wear pad is pressed against the raised step 20 of the power take-off housing, which can prevent the wear pad from rotating radially. In this embodiment, the vertical distance between the plane end of the wear pad and the center of the wear pad is 24 mm.

[0044] The working process of the power take-off transmission mechanism of the utility model is as follows.

[0045] The power take-off driving gear 15 meshes with the transmission power take-off gear, and the power take-off driving gear 15 rotates with the transmission power take-off gear, that is, the power take-off driving gear 15 obtains power from the transmission power take-off gear. The power take-off driving gear 15 is sleeved on the power take-off input shaft 4 through closely packed large-diameter needle roller bearings 16 and bearing spacers 17, that is, the driving gear 15 is sleeved on the input shaft 4, and the input shaft 4 is connected to the power take-off housing 1 through elastic cylindrical pins 19, which avoids radial rotation and axial movement of the input shaft 4, so the input shaft 4 does not rotate with the driving gear 15.

[0046] The driving gear 15 on the input shaft of the power take-off meshes with the driven gear 10 on the output shaft, that is, the driven gear 10 rotates with the driving gear 15, and the driving gear 15 on the input shaft transmits power to the driven gear 10 on the output shaft. The driven gear 10 is sleeved on the output shaft 3 through the needle bearing 14, that is, the driven gear 10 is sleeved on the output shaft 3, and the output shaft 3 does not rotate with the driven gear 10, and the power cannot be directly transmitted from the driven gear 10 to the output shaft 3.

[0047] When the power take-off is engaged, the compressed air at the pneumatic joint 7 of the power take-off enters the conical depression at the head end of the piston shaft 2 of the power take-off, exerting a force to the right on the piston shaft 2. The air in the enclosed space at the tail end of the piston shaft 2 is compressed, and the return spring 6 sleeved on the piston shaft is compressed, and the piston shaft 2 moves to the right. The shift fork 5 fixed on the piston shaft 2 moves to the right with the piston shaft 2, and the inclined surface on the shift fork 5 moves to the right with the shift fork 5, contacts and squeezes the shift signal switch 9, and the shift signal switch 9 is triggered, indicating that the power take-off is in the engaged state. Since the shift fork 5 is connected to the shift gear sleeve 11 on the output shaft, the shift gear sleeve 11 on the output shaft moves to the right with the shift fork 5 on the piston shaft. The shift gear sleeve 11 moves rightward to combine the driven gear coupling teeth and the external spline of the shift gear hub, and the shift gear hub 12 is combined with the output shaft 3 through the spline. At this time, the driven gear 10 is combined with the output shaft 3 through the shift gear sleeve 11 and the shift gear hub 12, and the output shaft 3 rotates with the driven gear 10, that is, the power is transmitted from the driven gear 10 to the output shaft 3, and the power is then transmitted to the external device through the output shaft 3.

[0048] When the power take-off is in the gear-engaging state, the position of the piston shaft 2 is stable, that is, the position of the shift fork 5 on the piston shaft 2 is stable, so that the shift sleeve 11 keeps the driven gear coupling teeth and the external spline of the shift hub engaged, and the power energy is continuously transmitted from the driving gear 15 on the input shaft 4 to the output shaft 3.

[0049] When the power take-off is switched to neutral, the pneumatic joint 7 no longer compresses air to enter, the air in the enclosed space at the rear end of the piston shaft 2 returns to its original state, and the return spring 6 on the piston shaft 2 pushes the shift fork 5 to move to the left, that is, the piston shaft 2 moves to the left and returns to its original state. The inclined surface on the shift fork moves to the left with the shift fork 5, and no longer squeezes the shift signal switch 9, and even does not contact the shift signal switch 9. The shift signal switch is disconnected and not triggered, and the power take-off is displayed in neutral at this time. The shift fork 5 is connected to the shift gear sleeve 11 on the output shaft. The shift gear sleeve 11 moves to the left with the shift fork 5, and no longer connects the driven gear coupling tooth and the shift gear hub external spline, that is, the output shaft does not rotate with the driven gear 10, and the power cannot be transmitted from the driven gear 10 to the output shaft 3.

[0050] When the power take-off is in neutral, the position of the piston shaft 2 is stable, that is, the positions of the shift fork 5 on the piston shaft and the shift gear sleeve 11 on the output shaft are stable, and power cannot be transmitted from the driven gear 10 to the output shaft 3.

[0051] The utility model adopts a large-diameter needle roller bearing to support the driving gear on the input shaft, so that the driving gear supporting bearing can withstand greater torque. There are enough gaps between the needle rollers for lubricating oil flow, which can enhance the heat dissipation capacity of the bearing and effectively control the thermal management of the transmission system. At the same time, the fatigue life index is improved. Compared with the tapered roller bearing, the fatigue life is higher. Under the same application torque, it can work for a long time, and its strength is more reliable and the performance is more stable, thereby extending the life of the power take-off, which can meet the continuous high-load use conditions of special vehicles such as high-pressure sprinklers, cement mixers, and agricultural mobile multi-functional work vehicles. It is also suitable for the power take-off of the vehicle gearbox to work for a long time. In addition, it has the characteristics of easy installation, can improve assembly efficiency, and is suitable for mass production. The active gear support structure such as the wear pad and the bearing is simple, which reduces the difficulty of assembly and can improve assembly efficiency. The gear control structure is simple, which reduces the cost and has a wider range of applications.

[0052] The above description is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural transformation made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A power take-off transmission mechanism, comprising a power take-off housing and an input shaft and an output shaft located inside the power take-off housing, characterized in that: The input shaft is provided with a driving gear, the driving gear is supported by a first bearing, and a bearing spacer is provided between the first bearing and the input shaft; The output shaft is provided with a shifting gear sleeve and a driven gear meshing with the driving gear; A piston shaft is also provided in the power take-off housing, a shift fork is provided on the piston shaft, and the shift fork is connected to the shift gear sleeve.

2. A power take-off transmission mechanism according to claim 1, characterized in that: The first bearing comprises an inner ring and an outer ring and a plurality of cylindrical rollers located in an annular space between the inner ring and the outer ring; cross sections at both ends of the first bearing are aligned with cross sections at both ends of the bearing spacer.

3. A power take-off transmission mechanism according to claim 2, characterized in that: The roller diameter is between 6 mm and 8 mm.

4. A power take-off transmission mechanism according to claim 2 or 3, characterized in that: The radial clearance between the plurality of rollers is between 0.04 mm and 0.08 mm.

5. A power take-off transmission mechanism according to claim 1, characterized in that: A wear pad is provided at each end of the bearing spacer: The wear pad is in the shape of a ring and is sleeved on the input shaft, and its edge is flush with the edge of the hub of the driving gear; A notch is provided at one end of the wear pad, the edge of the notch is a plane, a raised step is provided at a corresponding position of the power take-off housing, and the notch of the wear pad fits with the raised step of the power take-off housing.

6. A power take-off transmission mechanism according to claim 5, characterized in that: The wear pad is made of wear-resistant material bearing steel.

7. A power take-off transmission mechanism according to claim 1, characterized in that: An elastic cylindrical pin is also provided on the input shaft, and a through hole is provided on the input shaft perpendicular to the axial direction. A through hole is provided at a corresponding position of the power take-off housing. One end of the elastic cylindrical pin is embedded in the through hole on the input shaft, and the other end is embedded in the through hole on the power take-off housing.

8. A power take-off transmission mechanism according to claim 1, characterized in that: A return spring is sleeved on the piston shaft, one end of which is connected to the shift fork, and the other end is connected to the power take-off housing at the rear end of the piston shaft; a cylinder head is also provided on the power take-off housing at the front end of the piston shaft, and a pneumatic joint is provided on the cylinder head. The shift fork is fixed on the piston shaft, and a sealed space is provided between the rear end of the piston shaft and the power take-off housing.

9. A power take-off transmission mechanism according to claim 1 or 8, characterized in that: A shift signal switch is also provided on the power take-off housing, and the shift fork is provided with an inclined surface at a corresponding position of the shift signal switch.

10. A power take-off transmission mechanism according to claim 1, characterized in that: The output shaft is supported by a pair of deep groove ball bearings, and the driven gear is supported by a needle bearing.

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