Power assembly
By introducing components such as the first helical gear and limit gasket into the driving gear assembly of the powertrain, the axial force of the driving bevel gear and the first helical gear is mutually offset, and the problem of insufficient stability of the driving gear assembly in the prior art is solved, and higher structural stability is achieved.
Patent Information
- Application Number
- CN202422201773.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Priority Date
- 2024-06-24
- Filing Date
- 2024-09-07
- Publication Date
- 2025-06-20
- Estimated Expiration
- 2034-09-07
AI Technical Summary
The driving gear assembly in existing powertrains has poor stability, resulting in a reduced overall structural stability.
A powertrain is designed, and its driving gear assembly includes a first helical gear, an active bevel gear and an active gear shaft. Through a combination of a limiting gasket, an active gear bearing, a locking nut, a driving shaft sleeve and an active positioning bearing, the axial force of the driving bevel gear and the first helical gear cancels each other out, thereby improving stability.
The stability of the driving gear assembly is improved through mutually cancelled axial forces, thereby enhancing the overall structural stability of the powertrain.
Smart Images

Figure CN223004379U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power devices, and in particular to a power assembly. Background Art
[0002] At present, the powertrain includes a crank-connecting rod mechanism, a speed change mechanism and a gear transmission. The speed change mechanism is basically located in the gear transmission and is transmission-connected to the crank-connecting rod mechanism, so that the crank-connecting rod mechanism adjusts the output power through the speed change mechanism, thereby improving the overall performance of the powertrain.
[0003] In the prior art, the speed change mechanism includes a driving gear assembly for transmitting power, and the driving gear assembly includes a driving bevel gear and a driving gear shaft fixedly connected to the driving bevel gear. Since the driving bevel gear generates an axial force extending along the axial direction of the driving gear shaft during rotation, the driving bevel gear has poor stability, thereby reducing the structural stability of the driving gear assembly. Utility Model Content
[0004] In order to solve the deficiencies of the prior art, the purpose of the present application is to provide a powertrain whose driving gear assembly has high stability.
[0005] To achieve the above objectives, this application adopts the following technical solutions:
[0006] A powertrain, comprising a housing, a crank-connecting rod mechanism and a speed change mechanism, wherein the housing comprises a crankcase and a gearbox connected to the crankcase; the crank-connecting rod mechanism comprises a crankshaft, which is located in the crankcase; the speed change mechanism is at least partially located in the gearbox and is drivingly connected to the crankshaft; the gearbox comprises a gearbox, which is located on one side of the crankcase along the length direction of the powertrain, the speed change mechanism comprises a driving gear assembly, a driven gear assembly and a countershaft assembly located in the gearbox, and the driving gear assembly is drivingly connected to the countershaft assembly; the driving gear assembly comprises a first helical gear, a driving bevel gear and a driving gear shaft, the first helical gear and the driving bevel gear are respectively located on both sides of the driving gear shaft, the first helical gear and the driving bevel gear are both fixedly connected to the driving gear shaft, the driven gear assembly comprises a driven bevel gear, the countershaft assembly comprises a second helical gear, the driving bevel gear is drivingly connected to the driven bevel gear, the first helical gear is drivingly connected to the second helical gear, and the axial force generated by the rotation of the first helical gear is opposite to the axial force generated by the rotation of the driving bevel gear.
[0007] Further, the driving gear assembly further includes a limit gasket, a driving gear bearing, a locking nut, a driving shaft sleeve, and a driving positioning bearing. The limit gasket, the driving gear bearing, the locking nut, the driving shaft sleeve, and the driving positioning bearing are located between the driving bevel gear and the first helical gear. The limit gasket, the driving gear bearing, the locking nut, the driving shaft sleeve, and the driving positioning bearing are sequentially sleeved on the driving gear shaft. The axial forces generated by the rotation of the driving bevel gear and the first helical gear act on both sides of the driving gear bearing respectively.
[0008] Further, the gear transmission includes a driving bearing clamping portion and a driving positioning clamping portion. The driving gear bearing is clamped in the driving bearing clamping portion, and the driving positioning bearing is clamped in the driving positioning clamping portion.
[0009] Further, the speed change mechanism further includes a main shaft assembly located in the gear transmission. The main shaft assembly includes an output main shaft and a high-speed main shaft helical gear fixedly connected to the output main shaft. The countershaft assembly further includes a speed change countershaft and a high-speed countershaft helical gear sleeved on the speed change countershaft. The high-speed main shaft helical gear meshes with the high-speed countershaft helical gear. The axial force generated by the rotation of the high-speed countershaft helical gear is opposite to the axial force generated by the rotation of the second helical gear.
[0010] Further, the countershaft assembly further includes a middle bearing and a parking gear sleeved on the speed change countershaft. The middle bearing is located between the high-speed countershaft helical gear and the second helical gear. The speed change countershaft includes a countershaft shoulder. The axial force generated by the rotation of the high-speed countershaft helical gear acts on one side of the middle bearing through the countershaft shoulder, and the axial force generated by the rotation of the second helical gear acts on the other side of the middle bearing through the parking gear.
[0011] Further, the main shaft assembly further includes a low-speed main shaft helical gear fixedly connected to the output main shaft. The countershaft assembly further includes a low-speed countershaft helical gear and an end bearing sleeved on the speed change countershaft. The low-speed main shaft helical gear meshes with the low-speed countershaft helical gear. The end bearing is clamped with the gear transmission. The axial force generated by the rotation of the low-speed countershaft helical gear acts on the end bearing.
[0012] Further, the main shaft assembly further includes a reverse main shaft gear fixedly connected to the output main shaft. The reverse main shaft gear is axially located between the low-speed main shaft helical gear and the high-speed main shaft helical gear along the output main shaft, and the reverse main shaft gear is arranged close to the high-speed main shaft helical gear.
[0013] Further, the main shaft assembly further includes a main shaft bearing. The gear transmission includes a main shaft clamping portion. The main shaft bearing is clamped with the main shaft clamping portion. The axial force generated by the rotation of the low-speed main shaft helical gear or the axial force generated by the rotation of the low-speed main shaft helical gear acts on the main shaft bearing.
[0014] Further, the speed change mechanism further includes a reverse gear support shaft and a reverse gear transition gear, the countershaft assembly further includes a reverse countershaft gear, the reverse main shaft gear is drivingly connected to the countershaft reverse transition gear through the reverse gear transition gear, the reverse gear transition gear is sleeved on the reverse gear support shaft, the gear transmission further includes a first support portion and a second support portion, one end of the reverse gear support shaft is connected to the first support portion, and the other end of the reverse gear support shaft is connected to the second support portion.
[0015] Further, the driven gear assembly includes a front output shaft and a rear output shaft, both the front output shaft and the rear output shaft extend along the length direction of the power assembly, the rear end of the front output shaft is fixedly connected to the front end of the rear output shaft, the driven bevel gear is sleeved on the front output shaft and fixedly connected to the front output shaft, or the driven bevel gear is sleeved on the rear output shaft and fixedly connected to the rear output shaft.
[0016] The above-mentioned power assembly can arrange the axial force of the driving bevel gear and the axial force of the first helical gear oppositely, so that the axial force of the driving bevel gear and the axial force of the first helical gear can cancel each other out, thereby being beneficial to improving the stability of the driving gear assembly. Description of the Drawings
[0017] Figure 1 It is a schematic diagram of the overall structure of the power assembly provided by the embodiment of the present application.
[0018] Figure 2 It is a partial exploded view of the power assembly provided by the embodiment of the present application.
[0019] Figure 3 It is a partial exploded view of the gear transmission and the speed change mechanism of the power assembly provided by the embodiment of the present application.
[0020] Figure 4 It is a partial exploded view of the driven gear assembly of the power assembly provided by the embodiment of the present application.
[0021] Figure 5 It is an overall exploded view of the driven gear assembly of the power assembly provided by the embodiment of the present application.
[0022] Figure 6 It is a full cross-sectional view of the gear transmission and the speed change mechanism of the power assembly provided by the embodiment of the present application.
[0023] Figure 7 It is a full cross-sectional view of the gear transmission and the speed change mechanism of the power assembly provided by the embodiment of the present application from another angle.
[0024] Figure 8 It is a side view of the speed change mechanism of the power assembly provided by the embodiment of the present application.
[0025] Figure 9This is a partial cross-sectional view of the gearbox and the transmission mechanism of the powertrain provided by the embodiments of the present application.
[0026] Figure 10 This is an exploded view of the transmission assembly of the powertrain provided by the embodiments of the present application.
[0027] Figure 11 This is an orthographic three-axis view of the transmission mechanism of the powertrain provided by the embodiments of the present application. Detailed implementation manners
[0028] To enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the specific implementation manners of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the implementation manners of the present application.
[0029] As Figure 1 and Figure 2A powertrain 100 is shown, which includes a housing 11, a crank connecting rod mechanism 12, a transmission mechanism 13, a valve train mechanism 14, a starting mechanism 15 and a lubrication mechanism 16. The housing 11 constitutes the basic framework of the powertrain 100. An accommodation space 101 is formed inside the housing 11, and the accommodation space 101 is used to accommodate and protect the internal components of the powertrain 100. Among them, the housing 11 includes a cylinder head cover 111, a cylinder head 112, a cylinder block 113, a crankcase 114, an oil pan 115 and a gearbox 116. Among them, the cylinder head cover 111, the cylinder head 112, the cylinder block 113, the crankcase 114 and the oil pan 115 are connected in sequence, and the gearbox 116 is connected to the crankcase 114. The accommodation space 101 is basically formed by the mutual connection of the cylinder head cover 111, the cylinder head 112, the cylinder block 113, the crankcase 114, the oil pan 115 and the gearbox 116. The crank connecting rod mechanism 12 is at least partially arranged in the crankcase 114. The crank connecting rod mechanism 12 includes a crankshaft 121 and a connecting rod assembly 122 connected to the crankshaft 121. The crankshaft 121 is located inside the crankcase 114 and is rotatably connected to the crankcase 114. The connecting rod assembly 122 is at least partially located inside the crankcase 114 and at least partially located in the cylinder block 113. The transmission mechanism 13 is located inside the gearbox 116, and the transmission mechanism 13 is in transmission connection with the crankshaft 121. The valve train mechanism 14 is at least partially arranged in the accommodation space 101, and the valve train mechanism 14 is in transmission connection with the crankshaft 121. The starting mechanism 15 is located outside the crankcase 114 and is connected to the crankcase 114. The starting mechanism 15 at least partially passes through the crankcase 114 and is in transmission connection with the crankshaft 121. The lubrication mechanism 16 is at least partially located inside the oil pan 115, and the lubrication mechanism 16 is arranged through the cylinder head 112, the cylinder block 113 and the crankcase 114 to realize lubricating the internal components of the housing 11. When the powertrain 100 is working, fuel and air are mixed into a combustible mixture and then delivered to the combustion chamber 1120 of the powertrain 100. After the combustible mixture burns, a large amount of heat is released, and the gas pressure and temperature in the cylinder block 113 rise rapidly, thereby driving the connecting rod assembly 122 to move. Among them, the combustion chamber 1120 of the powertrain 100 is composed of the bottom of the cylinder head 112 and the top of the cylinder block 113. The crankshaft 121 is connected to the connecting rod assembly 122, and the movement of the connecting rod assembly 122 can drive the crankshaft 121 to move, so that the crank connecting rod mechanism 12 can output power. To clearly illustrate the technical solution of this application, the following is also defined as Figure 1Front, rear, left, right, top and bottom as shown. It can be understood that in the embodiments of the present application, the front-rear direction refers to the length direction of the powertrain 100, the left-right direction refers to the width direction of the powertrain 100, and the up-down direction refers to the height direction of the powertrain 100. Among them, the cylinder head cover 111, the cylinder head 112, the cylinder block 113, the crankcase 114 and the oil pan 115 are basically distributed along the up-down direction, that is, the crankcase 114 is arranged on the upper side of the oil pan 115, the cylinder block 113 is arranged on the upper side of the crankcase 114, the cylinder head 112 is arranged on the upper side of the cylinder block 113, and the cylinder head cover 111 is arranged on the upper side of the cylinder head 112.
[0030] As Figure 3 and Figure 4 shown, as an implementation manner, the transmission 116 includes a gear transmission 1161, and the transmission mechanism 13 includes a driven gear assembly 131 located in the gear transmission 1161. Along the length direction of the powertrain 100, the gear transmission 1161 is located on one side of the crankcase 114, that is, the gear transmission 1161 is located on the front side or the rear side of the crankcase 114. The above setting can avoid arranging the gear transmission 1161 on the left side or the right side of the crankcase 114, which may cause the width of the powertrain 100 to be too large, thus helping to reduce the width of the powertrain 100.
[0031] In this embodiment, the driven gear assembly 131 includes a front output shaft 1311, a rear output shaft 1312 and a driven bevel gear 1313. Both the front output shaft 1311 and the rear output shaft 1312 extend along the length direction of the powertrain 100. The rear end of the front output shaft 1311 is fixedly connected or integrally formed with the front end of the rear output shaft 1312. The driven bevel gear 1313 is sleeved on the front output shaft 1311 and fixedly connected to the front output shaft 1311, or the driven bevel gear 1313 is sleeved on the rear output shaft 1312 and fixedly connected to the rear output shaft 1312. Through the above setting, the front output shaft 1311 and the rear output shaft 1312 can be integrally arranged, which is beneficial to improving the connection strength between the front output shaft 1311 and the rear output shaft 1312, and further beneficial to improving the structural stability of the driven gear assembly 131.
[0032] Exemplarily, an external connection portion 1311a is provided on the front output shaft 1311. The external connection portion 1311a is disposed near the connection between the front output shaft 1311 and the rear output shaft 1312. An internal connection portion 1313a is provided inside the driven bevel gear 1313. The external connection portion 1311a and the internal connection portion 1313a are detachably connected. Specifically, the external connection portion 1311a and the internal connection portion 1313a can be configured as a spline connection, so that the external connection portion 1311a can be clamped on the internal connection portion 1313a, thereby improving the assembly speed of the driven bevel gear 1313 and the front output shaft 1311, and further facilitating the improvement of the assembly efficiency of the driven gear assembly 131. Or an external connection portion 1311a is provided on the rear output shaft 1312. The external connection portion 1311a is disposed near the connection between the front output shaft 1311 and the rear output shaft 1312. An internal connection portion 1313a is provided inside the driven bevel gear 1313. The external connection portion 1311a and the internal connection portion 1313a are detachably connected. Specifically, the external connection portion 1311a and the internal connection portion 1313a can be configured as a spline connection, so that the external connection portion 1311a can be clamped on the internal connection portion 1313a, thereby improving the assembly speed of the driven bevel gear 1313 and the rear output shaft 1312, and further facilitating the improvement of the assembly efficiency of the driven gear assembly 131.
[0033] As an implementation, the driven gear assembly 131 further includes a first driven bearing 1314 and a second driven bearing 1315. The first driven bearing 1314 is sleeved on the front output shaft 1311 and rotatably connected to the front output shaft 1311. The second driven bearing 1315 is sleeved on the rear output shaft 1312 and rotatably connected to the rear output shaft 1312. The driven bevel gear 1313 is located between the first driven bearing 1314 and the second driven bearing 1315. Specifically, the first driven bearing 1314 and the second driven bearing 1315 are used to support the front output shaft 1311, the rear output shaft 1312 and the driven bevel gear 1313. In this application, it is possible to avoid setting too many bearings on the output shaft or the rear output shaft 1312, resulting in an over-large volume or over-heavy mass of the driven gear assembly 131. Through the above settings, the volume of the driven gear assembly 131 can be reduced, which is beneficial to improving the space utilization rate of the power assembly 100. At the same time, the mass of the driven gear assembly 131 can also be reduced, thereby realizing the light weight of the power assembly 100.
[0034] In this embodiment, a first driven engaging portion 1161a and a second driven engaging portion 1161b are provided in the gear transmission 1161. The first driven bearing 1314 is engaged with the first driven engaging portion 1161a, and the second driven bearing 1315 is engaged with the second driven engaging portion 1161b. Specifically, the gear transmission 1161 includes a first gear housing 1161c and a second gear housing 1161d. The first gear housing 1161c and the second gear housing 1161d are detachably connected. A first engaging groove 1161e is provided on the first driven engaging portion 1161a, and a second engaging groove 1161f is provided on the second driven engaging portion 1161b. The first engaging groove 1161e and the second engaging groove 1161f are provided at the connection of the first gear housing 1161c and the second gear housing 1161d, that is, the first engaging groove 1161e and the second engaging groove 1161f are at least partially located in the first gear housing 1161c, and the first engaging groove 1161e and the second engaging groove 1161f are also at least partially located in the second gear housing 1161d. Through the above settings, it is convenient to assemble the first driven bearing 1314 in the first engaging groove 1161e, and it is also convenient to assemble the second driven bearing 1315 in the second engaging groove 1161f, which is beneficial to improving the assembly speed of the first driven bearing 1314 and the second driven bearing 1315, and further improving the assembly efficiency of the driven gear assembly 131.
[0035] As Figure 5 shown, as an implementation, the driven gear assembly 131 further includes an adjusting shim 1316 and a bearing bushing 1317. The adjusting shim 1316 is sleeved on the front output shaft 1311. The two sides of the adjusting shim 1316 are respectively abutted against the first driven bearing 1314 and the driven bevel gear 1313. The rear output shaft 1312 includes an output shaft neck 1312a. The two ends of the second driven bearing 1315 are respectively abutted against the bearing bushing 1317 and the output shaft neck 1312a. Specifically, the adjusting shim 1316 can prevent interference between the first driven bearing 1314 and the driven bevel gear 1313, which is beneficial to protecting the first driven bearing 1314 or the driven bevel gear 1313. The bearing bushing 1317 can limit the sliding of the second driven bearing 1315 on the rear output shaft 1312, so that the connection between the second driven bearing 1315 and the rear output shaft 1312 is more stable, which is beneficial to improving the structural stability of the driven gear assembly 131.
[0036] In this embodiment, the driven gear assembly 131 further includes a bearing stopper 1318, a bearing connection portion 1311b is provided on the front output shaft 1311, the bearing stopper 1318 abuts against one end of the first driven bearing 1314 away from the adjustment washer 1316, and the bearing stopper 1318 is fixedly connected to the bearing connection portion 1311b. Specifically, the bearing stopper 1318 can be set as a nut, and a thread can be provided on the bearing connection portion 1311b, so that the bearing stopper 1318 and the bearing connection portion 1311b can be fixedly connected, wherein the bearing stopper 1318 can limit the sliding of the first driven bearing 1314 on the front output shaft 1311, so that the connection between the second driven bearing 1315 and the front output shaft 1311 is more stable, thereby facilitating the improvement of the structural stability of the driven gear assembly 131.
[0037] As an implementation method, the driven gear assembly 131 also includes a first oil seal 1319 and a second oil seal 131a. The first oil seal 1319 is sleeved on the front output shaft 1311, and the first oil seal 1319 is located at the end of the bearing limiter 1318 away from the first driven bearing 1314. The second oil seal 131a is sleeved on the rear output shaft 1312, and the second oil seal 131a is located at the end of the second driven bearing 1315 away from the driven bevel gear 1313. Specifically, the first driven bearing 1314 and the second driven bearing 1315 are soaked with lubricating oil, the first oil seal 1319 is clamped at least partially close to the first driven clamping portion 1161a, and the first oil seal 1319 is used to seal the first driven bearing 1314 in the first gear housing 1161c, and the second oil seal 131a is at least partially close to the second driven clamping portion 1161b, and the second oil seal 131a is used to seal the second driven bearing 1315 in the second gear housing 1161d. Through the above arrangement, the lubrication effect of the first driven bearing 1314 and the second driven bearing 1315 can be improved, so as to increase the service life of the first driven bearing 1314 and the second driven bearing 1315, thereby facilitating the improvement of the service life of the driven gear assembly 131.
[0038] like Figure 6 As shown, as an implementation, the speed change mechanism 13 further includes a driving gear assembly 132 located in the gear box 1161, and the driving gear assembly 132 is transmission-connected with the driven gear assembly 131. Specifically, the driving gear assembly 132 includes a driving bevel gear 1321 and a driving gear shaft 1322 fixedly connected to the driving bevel gear 1321, and the driving bevel gear 1321 is transmission-connected with the driven bevel gear 1313. Through the above arrangement, the power of the driving bevel gear 1321 is transmitted to the front output shaft 1311 and the rear output shaft 1312 through the driven bevel gear 1313, thereby realizing the power transmission of the power assembly 100.
[0039] In this embodiment, the speed change mechanism 13 further includes a countershaft assembly 133 located within the gear transmission 1161, and the countershaft assembly 133 is in transmission connection with the driving gear assembly 132. Specifically, the driving gear assembly 132 includes a first helical gear 1323. The first helical gear 1323 and the driving bevel gear 1321 are respectively located on both sides of the driving gear shaft 1322 and fixedly connected to the driving gear shaft 1322. The countershaft assembly 133 includes a second helical gear 1331. The first helical gear 1323 is in transmission connection with the second helical gear 1331. The axial force generated by the rotation of the first helical gear 1323 is opposite to the axial force generated by the rotation of the driving bevel gear 1321, that is, the axial force of the first helical gear 1323 relative to the second helical gear 1331 is opposite to the axial force of the driving bevel gear 1321 relative to the driven bevel gear 1313. More specifically, along the width direction of the power assembly 100, the teeth of the driving bevel gear 1321 are set to be left-handed, and the teeth of the first helical gear 1323 are set to be right-handed. When the driving gear assembly 132 rotates, the axial force generated by the rotation of the driving bevel gear 1321 moves along its own rotation center towards the direction close to the first helical gear 1323, and the axial force generated by the rotation of the first helical gear 1323 moves along its own rotation center towards the direction close to the driving bevel gear 1321. Through the above settings, the axial force generated by the rotation of the driving bevel gear 1321 and the axial force generated by the rotation of the first helical gear 1323 are oppositely arranged or offset from each other, which is beneficial to improving the stability of the driving gear assembly 132, and further improving the working stability of the power assembly 100.
[0040] As another implementation manner, along the width direction of the power assembly 100, the teeth of the driving bevel gear 1321 are set to be right-handed, and the teeth of the first helical gear 1323 are set to be left-handed. When the driving gear assembly 132 rotates, the axial force generated by the rotation of the driving bevel gear 1321 moves along its own rotation center towards the direction away from the first helical gear 1323, and the axial force generated by the rotation of the first helical gear 1323 moves along its own rotation center towards the direction away from the driving bevel gear 1321. Through the above settings, the axial force generated by the rotation of the driving bevel gear 1321 and the axial force generated by the rotation of the first helical gear 1323 are oppositely arranged or offset from each other, which is beneficial to improving the stability of the driving gear assembly 132, and further improving the working stability of the power assembly 100.
[0041] As an implementation, the driving gear assembly 132 further includes a limit gasket 1324, a driving gear bearing 1325, a locking nut 1326, a driving shaft sleeve 1327, and a driving positioning bearing 1328 sleeved on the driving gear shaft 1322. The limit gasket 1324, the driving gear bearing 1325, the locking nut 1326, the driving shaft sleeve 1327, and the driving positioning bearing 1328 are sequentially located between the driving bevel gear 1321 and the first helical gear 1323. The axial force generated by the rotation of the driving bevel gear 1321 and the axial force generated by the rotation of the first helical gear 1323 act on both sides of the driving gear bearing 1325 respectively. Specifically, the axial force generated by the rotation of the driving bevel gear 1321 acts on one side of the driving gear bearing 1325 through the limit gasket 1324, and the axial force generated by the rotation of the first helical gear 1323 acts on the other side of the driving gear bearing 1325 through the driving positioning bearing 1328, the driving shaft sleeve 1327, and the locking nut 1326. More specifically, the driving bevel gear 1321, the first helical gear 1323, the driving gear shaft 1322, the limit gasket 1324, the locking nut 1326, and the driving shaft sleeve 1327 are all connected to the gear transmission 1161 through the driving positioning bearing 1328 and the driving gear bearing 1325. The limit gasket 1324 is located between the driving bevel gear 1321 and the driving gear bearing 1325 to avoid interference between the driving bevel gear 1321 and the driving gear bearing 1325, which is beneficial to protecting the driving bevel gear 1321 and the driving gear bearing 1325. At the same time, the axial force generated by the rotation of the driving bevel gear 1321 and the axial force generated by the rotation of the first helical gear 1323 both act on the driving gear bearing 1325 to achieve balanced stress on both sides of the driving gear bearing 1325, which is beneficial to improving the service life of the driving gear bearing 1325 and also beneficial to improving the service life of the driving gear assembly 132.
[0042] In this embodiment, the gear transmission 1161 includes a driving bearing clamping portion 1161g and a driving positioning clamping portion 1161h. The driving gear bearing 1325 is clamped in the driving bearing clamping portion 1161g, and the driving positioning bearing 1328 is clamped in the driving positioning clamping portion 1161h. Specifically, a third clamping groove 1161j is formed on the driving bearing clamping portion 1161g, and a fourth clamping groove 1161k is formed on the driving positioning clamping portion 1161h. Both the third clamping groove 1161j and the fourth clamping groove 1161k are located in the second gear housing 1161d. The driving gear bearing 1325 is clamped in the third clamping groove 1161j, and the driving positioning bearing 1328 is clamped in the fourth clamping groove 1161k. Through the above settings, it is convenient for the installation of the driving gear bearing 1325 and the driving positioning bearing 1328, which is beneficial to improving the assembly speed of the driving gear bearing 1325 and the driving positioning bearing 1328, and further improving the assembly efficiency of the driving gear assembly 132.
[0043] As an implementation, the variable speed mechanism 13 further includes a main shaft assembly 134 located within the gear transmission 1161. The main shaft assembly 134 includes an output main shaft 1341 and a high-speed main shaft helical gear 1342 fixedly connected to the output main shaft 1341. The countershaft assembly 133 further includes a variable speed countershaft 1332 and a high-speed countershaft helical gear 1333 sleeved on the variable speed countershaft 1332. The high-speed main shaft helical gear 1342 meshes with the high-speed countershaft helical gear 1333. The axial force generated by the rotation of the high-speed countershaft helical gear 1333 is opposite to the axial force generated by the rotation of the second helical gear 1331. Through the above arrangement, the axial force generated by the rotation of the high-speed countershaft helical gear 1333 is oppositely arranged or mutually offset with the axial force generated by the rotation of the second helical gear 1331, which is beneficial to improving the stability of the countershaft assembly 133, and further improving the working stability of the power assembly 100.
[0044] In this embodiment, the countershaft assembly 133 further includes a middle bearing 1334 and a parking gear 1335 sleeved on the variable speed countershaft 1332. The middle bearing 1334 is located between the high-speed countershaft helical gear 1333 and the second helical gear 1331. The variable speed countershaft 1332 includes a countershaft shoulder 1332a. The axial force generated by the rotation of the high-speed countershaft helical gear 1333 acts on one side of the middle bearing 1334 through the countershaft shoulder 1332a, and the axial force generated by the rotation of the second helical gear 1331 acts on the other side of the middle bearing 1334 through the parking gear 1335. Specifically, the countershaft assembly 133 is connected to the gear transmission 1161 through the middle bearing 1334. One side of the second helical gear 1331 abuts against one side of the middle bearing 1334, and the other side of the second helical gear 1331 abuts against the parking gear 1335. Moreover, the middle bearing 1334, the second helical gear 1331, and the parking gear 1335 are all fixed on the variable speed countershaft 1332 through fastening nuts and circular gaskets, so that the axial force generated by the rotation of the second helical gear 1331 can directly act on the middle bearing 1334, or act on the middle bearing 1334 after the reaction forces of the parking gear 1335, the fastening nuts, and the circular gaskets. More specifically, the high-speed countershaft helical gear 1333 is fixedly connected to the variable speed countershaft 1332, and the acting force of the high-speed countershaft helical gear 1333 directly acts on the middle bearing 1334 through the variable speed countershaft 1332. Through the above arrangement, the axial force generated by the rotation of the second helical gear 1331 and the axial force generated by the rotation of the high-speed countershaft helical gear 1333 both act on the middle bearing 1334, and the axial forces of the two cancel each other out, so as to achieve balanced stress on both sides of the middle bearing 1334, which is beneficial to improving the service life of the middle bearing 1334 and also beneficial to improving the service life of the countershaft assembly 133.
[0045] As an implementation manner, the main shaft assembly 134 further includes a low-speed main shaft helical gear 1343 fixedly connected to the output main shaft 1341. The countershaft assembly 133 further includes a low-speed countershaft helical gear 1336 sleeved on the countershaft 1332 and an end bearing 1337. The low-speed main shaft helical gear 1343 meshes with the low-speed countershaft helical gear 1336. The end bearing 1337 is clamped with the gear transmission 1161. The axial force generated by the rotation of the low-speed countershaft helical gear 1336 acts on the end bearing 1337. Specifically, the countershaft assembly 133 is also connected to the gear transmission 1161 through the end bearing 1337. The end bearing 1337 is sleeved on one end of the countershaft 1332 away from the parking gear 1335. The end bearing 1337 is abutted against the low-speed countershaft helical gear 1336 through a circular gasket. When the teeth of the low-speed countershaft helical gear 1336 are left-handed, the axial force generated by the rotation of the low-speed countershaft helical gear 1336 acts on the end bearing 1337, so that the end bearing 1337 can share part of the axial force of the countershaft assembly 133, thereby avoiding the excessive concentration of the axial force generated by the rotation of the countershaft assembly 133, and further being beneficial to improving the working stability of the countershaft assembly 133.
[0046] As another possible implementation manner, the low-speed countershaft helical gear 1336 can be fixedly connected to the countershaft 1332, and the low-speed main shaft helical gear 1343 and the low-speed countershaft helical gear 1336 cannot do work on the countershaft 1332 at the same time. When the teeth of the low-speed countershaft helical gear 1336 are right-handed, the axial force generated by the rotation of the low-speed countershaft helical gear 1336 acts on the middle bearing 1334 through the countershaft 1332, so that the axial force generated by the rotation of the low-speed countershaft helical gear 1336 cancels out the axial force generated by the rotation of the second helical gear 1331, so as to achieve the balanced force on both sides of the middle bearing 1334, and further being beneficial to improving the service life of the middle bearing 1334 and also being beneficial to improving the service life of the countershaft assembly 133.
[0047] As an implementation, the main shaft assembly 134 further includes a main shaft bearing 1344. The gear transmission 1161 includes a main shaft clamping portion 1161m. The main shaft bearing 1344 is clamped with the main shaft clamping portion 1161m. The axial force generated by the rotation of the low-speed main shaft helical gear 1343 or the axial force generated by the rotation of the low-speed main shaft helical gear 1343 acts on the main shaft bearing 1344. Specifically, the output main shaft 1341, the low-speed main shaft helical gear 1343, and the high-speed main shaft helical gear 1342 are all connected to the gear transmission 1161 through the main shaft bearing 1344, and the low-speed main shaft helical gear 1343 and the high-speed main shaft helical gear 1342 work alternately, so that the circumferential force of the low-speed main shaft helical gear 1343 can be transmitted to the main shaft bearing 1344 through the output main shaft 1341, or the circumferential force of the high-speed main shaft helical gear 1342 can be transmitted to the main shaft bearing 1344 through the output main shaft 1341. Through the above settings, since the axial force generated by the rotation of the low-speed main shaft helical gear 1343 and the axial force generated by the rotation of the low-speed main shaft helical gear 1343 are small, and the main shaft bearing 1344 can be set as a double-ball bearing, the load-bearing capacity of the main shaft bearing 1344 is large, which is beneficial to balancing the axial force generated by the rotation of the low-speed main shaft helical gear 1343 or the axial force generated by the rotation of the low-speed main shaft helical gear 1343, and thus is beneficial to improving the working stability of the main shaft assembly 134.
[0048] As an implementation, the main shaft assembly 134 further includes a reverse main shaft gear 1345 fixedly connected to the output main shaft 1341. The reverse main shaft gear 1345 is located between the low-speed main shaft helical gear 1343 and the high-speed main shaft helical gear 1342 along the axial direction of the output main shaft 1341, and the reverse main shaft gear 1345 is arranged close to the high-speed main shaft helical gear 1342. Specifically, since there is a large space between the low-speed main shaft helical gear 1343 and the high-speed main shaft helical gear 1342, the reverse main shaft gear 1345 is arranged in the above space, which is beneficial to improving the space utilization rate of the main shaft assembly 134. At the same time, the structure of the reverse main shaft gear 1345 and the high-speed main shaft helical gear 1342 is more compact, and thus is also beneficial to improving the structural compactness of the main shaft assembly 134.
[0049] Such as Figure 7As shown, in this embodiment, the speed change mechanism 13 further includes a reverse gear assembly 135 located within the gear transmission 1161. The reverse gear assembly 135 includes a reverse gear support shaft 1351 and a reverse gear transition gear 1352. The countershaft assembly 133 further includes a reverse countershaft gear 1338. The reverse main shaft gear 1345 is drivingly connected to the reverse countershaft gear 1338 through the reverse gear transition gear 1352. Specifically, the reverse main shaft gear 1345 meshes with the reverse gear transition gear 1352, and the reverse countershaft gear 1338 also meshes with the reverse gear transition gear 1352. Among them, when observed in the width direction of the powertrain 100, the reverse countershaft gear 1338 is located between the output main shaft 1341 and the speed change countershaft 1332, so that the structures of the reverse countershaft gear 1338, the reverse gear support shaft 1351, the speed change countershaft 1332, and the output main shaft 1341 are more compact, which is conducive to improving the structural compactness of the speed change mechanism 13.
[0050] As an implementation, the reverse gear transition gear 1352 is sleeved on the reverse gear support shaft 1351. The gear transmission 1161 further includes a first support portion 1161n and a second support portion 1161p. One end of the reverse gear support shaft 1351 is connected to the first support portion 1161n, and the other end of the reverse gear support shaft 1351 is connected to the second support portion 1161p. Specifically, the reverse gear support shaft 1351 has a cylindrical structure. A first support circular hole is provided on the first support portion 1161n, and a second support circular hole is provided on the second support portion 1161p, so that both ends of the reverse gear support shaft 1351 are respectively clamped in the first support circular hole and the second support circular hole. Through the above settings, the connection stability between the reverse gear support shaft 1351 and the gear transmission 1161 can be improved, which is conducive to improving the stability of the reverse gear transition gear 1352, and further conducive to improving the stability of the reverse gear assembly 135.
[0051] In this embodiment, the first support portion 1161n is provided in the first gear housing 1161c, the second support portion 1161p is provided in the second gear housing 1161d, and the reverse gear transition gear 1352 is located in the second gear housing 1161d and is disposed close to the second support portion 1161p. Specifically, when the reverse gear support shaft 1351 and the reverse gear transition gear 1352 need to be repaired or replaced, the first gear housing 1161c and the second gear housing 1161d can be disassembled to facilitate the assembly of the reverse gear support shaft 1351 and the reverse gear transition gear 1352, and the reverse gear support shaft 1351 is supported by both the first gear housing 1161c and the second gear housing 1161d. Through the above settings, the assembly efficiency of the reverse gear support shaft 1351 and the reverse gear transition gear 1352 can be improved, and it is also conducive to improving the structural stability of the reverse gear support shaft 1351.
[0052] As Figure 8As shown, as an implementation, the speed change mechanism 13 further includes a shift component 136 and a speed change component 137. The speed change component 137 controls the transmission ratio between the main shaft component 134 and the countershaft component 133 through the shift component 136. Both the speed change component 137 and the shift component 136 are at least partially disposed in front of the countershaft component 133. Specifically, both the speed change component 137 and the shift component 136 are at least partially disposed below the main shaft component 134, and both the speed change component 137 and the shift component 136 are at least partially disposed above the driving gear component 132 and the driven gear component 131. Through the above arrangement, the structures of the speed change component 137, the shift component 136, the countershaft component 133, the main shaft component 134, the driving gear component 132, and the driven gear component 131 can be made more compact, which is conducive to improving the structural compactness of the speed change mechanism 13.
[0053] As Figure 9 shown, in this embodiment, the speed change component 137 includes a speed change hub 1371, a first speed change bearing 1372, and a second speed change bearing 1373. The first speed change bearing 1372 and the second speed change bearing 1373 are respectively sleeved at both ends of the speed change hub 1371 and are rotatably connected to the speed change hub 1371. A first speed change clamping portion 1161q is provided in the first gear box body 1161c, and a second speed change clamping portion 1161r is provided in the second gear box body 1161d. The first speed change bearing 1372 is clamped in the first speed change clamping portion 1161q, and the second speed change bearing 1373 is clamped in the second speed change clamping portion 1161r. Specifically, the speed change hub 1371 is connected to the gear transmission box 1161 through the first speed change bearing 1372 and the second speed change bearing 1373, and the speed change hub 1371 needs to rotate in the gear transmission box 1161. Therefore, in this application, the excessive friction between the speed change hub 1371 and the gear transmission box 1161 caused by the direct connection between the speed change hub 1371 and the gear transmission box 1161 is avoided, so as to prevent the end of the speed change hub 1371 from being worn, which is conducive to improving the service life of the speed change component 137. Through the above arrangement, the first speed change bearing 1372 and the second speed change bearing 1373 can increase the rotation speed of the speed change hub 1371, thereby improving the working efficiency of the speed change component 137.
[0054] As an implementation manner, the shift component 136 includes a shift shaft 1361, a shift fork 1362, a shift elastic member 1363, and a shift slider 1364. There are at least two shift forks 1362, and the shift fork 1362 is used to control the transmission ratio of the transmission mechanism 13. Both the shift fork 1362 and the shift slider 1364 are slidably connected to the shift shaft 1361 so that the shift fork 1362 and the shift slider 1364 can move axially along the shift shaft 1361. Among them, the shift elastic member 1363 is sleeved on the shift shaft 1361, and both the shift elastic member 1363 and the shift slider 1364 are arranged between two adjacent shift forks 1362. Specifically, the transmission component 137 further includes a fork groove 1374 and a slider groove 1375 formed in the transmission hub 1371. At least part of the shift fork 1362 is clamped in the fork groove 1374, and at least part of the shift slider 1364 is clamped in the slider groove 1375. More specifically, the left and right sides of the shift elastic member 1363 respectively abut against the shift fork 1362 and the shift slider 1364.
[0055] In this embodiment, the transmission component 137 can rotate around its own axis, that is, the transmission mechanism 13 rotates, and the fork groove 1374 and the slider groove 1375 also rotate. Since at least part of the shift fork 1362 is arranged in the fork groove 1374 and at least part of the shift slider 1364 is arranged in the slider groove 1375, the shift fork 1362 and the shift slider 1364 slide in the fork groove 1374 and the slider groove 1375, and then the shift fork 1362 and the shift slider 1364 slide left and right on the shift shaft 1361. At this time, the sliding of the shift fork 1362 and the shift slider 1364 on the shift shaft 1361 can drive the shift elastic member 1363 to slide on the shift shaft 1361, and the elastic force generated by the expansion and contraction of the shift elastic member 1363 during the sliding process acts on the shift fork 1362 and the shift slider 1364, which is beneficial to improving the moving smoothness of the shift fork 1362 and the shift slider 1364 on the shift shaft 1361, and further beneficial to improving the shifting stability and accuracy of the shift component 136. Through the above settings, the stable operation of the shift component 136 is realized, which is beneficial to improving the working efficiency of the transmission mechanism 13, avoiding the hard connection between the shift component 136 and the transmission component 137, and further improving the service life of the powertrain 100.
[0056] Such as Figure 10As shown, by way of example, when there are two shift forks 1362, the fork slots 1374 include a first slot body 1374a and a second slot body 1374b. The first slot body 1374a, the second slot body 1374b, and the slider slot 1375 all extend substantially along the circumferential direction of the speed change hub 1371, and the lengths of the first slot body 1374a, the second slot body 1374b, and the slider slot 1375 in the circumferential direction of the speed change hub 1371 are substantially the same. Specifically, during the rotation of the speed change mechanism 13, one of the shift forks 1362 can slide within the first slot body 1374a, and the other shift fork 1362 can slide within the second slot body 1374b. Thus, the first slot body 1374a can control one of the shift forks 1362 to slide on the shift shaft 1361, and the second slot body 1374b can control the other shift fork 1362 to slide on the shift shaft 1361, thereby improving the working efficiency between the speed change assembly 137 and the shift assembly 136 to achieve the shifting and speed changing function of the speed change mechanism 13. In addition, the slider slot 1375 is axially located between the first slot body 1374a and the second slot body 1374b along the speed change hub 1371. During the rotation of the speed change mechanism 13, the shift slider 1364 can slide within the slider slot 1375, and the slider slot 1375 can control the shift slider 1364 to slide on the shift shaft 1361, so that the shift slider 1364 can push the shift fork 1362 to slide through the shift elastic member 1363, thereby improving the sliding efficiency of the shift fork 1362 and further improving the working efficiency of the shift assembly 136.
[0057] As Figure 8 and Figure 11 shown, as an implementation, the speed change mechanism 13 further includes a shift actuator 138 and a shift gear assembly 139. The shift gear assembly 139 is at least partially located within the gear transmission 1161 and is in transmission connection with the speed change assembly 137. The shift actuator 138 is substantially located outside the transmission 116 body, and the shift actuator 138 is in transmission connection with the speed change assembly 137 through the shift gear assembly 139. Specifically, a through hole is formed on the gear transmission 1161, and at least a part of the shift actuator 138 passes through the through hole and is located inside the gear transmission 1161 so that the shift actuator 138 can be rotationally connected to the shift gear assembly 139. Among them, the shift actuator 138 can adjust the rotation angle of the shift gear assembly 139 to achieve the adjustment of the rotation angle of the speed change assembly 137, so that the speed change assembly 137 can drive the shift assembly 136 to work according to actual needs. Through the above settings, the shift actuator 138 has high precision to achieve precise control of the shift assembly 136, which is beneficial to improving the working accuracy of the speed change mechanism 13.
[0058] In this embodiment, the speed change assembly 137 further includes a shift speed change shaft 1376 and a speed change gear 1377 connected to the speed change hub 1371. The speed change gear 1377 is fixedly connected to the shift speed change shaft 1376. The shift actuator 138 includes an actuator gear 1381. The shift gear assembly 139 includes a shift rotating shaft 1391, a first shift gear 1392 and a second shift gear 1393 fixedly connected to the shift rotating shaft 1391. The actuator gear 1381 meshes with the first shift gear 1392, and the speed change gear 1377 meshes with the second shift gear 1393. Specifically, the driving force of the actuator gear 1381 is transmitted to the speed change gear 1377 through the first shift gear 1392 and the second shift gear 1393, and then the speed change gear 1377 transmits the driving force to the speed change hub 1371 through the shift speed change shaft 1376 to control the rotation of the speed change hub 1371. Through the above arrangement, the transmission efficiency of the actuator gear 1381, the first shift gear 1392, the second shift gear 1393 and the speed change gear 1377 is relatively high, which is beneficial to improving the working efficiency of the speed change assembly 137, the shift actuator 138 and the shift gear assembly 139. It should be noted that the size of the first shift gear 1392 is larger than that of the actuator gear 1381, the size of the first shift gear 1392 is also larger than that of the second shift gear 1393, and the size of the second shift gear 1393 is less than or equal to the size of the speed change gear 1377. Specifically, since the rotation speed of the actuator gear 1381 is relatively fast, the transmission ratio between the first shift gear 1392 and the actuator gear 1381 is increased in this application so that the rotation speed of the first shift gear 1392 is less than that of the actuator gear 1381. Similarly, the first shift gear 1392 and the second shift gear 1393 are fixedly connected to the same shaft, and the number of teeth of the first shift gear 1392 is much larger than that of the second shift gear 1393, thereby reducing the rotation speed of the second shift gear 1393 so that the rotation speed of the speed change gear 1377 is much less than that of the actuator gear 1381, and further enabling the shift actuator 138 to accurately control the rotation angle of the speed change assembly 137, thereby improving the working accuracy of the speed change mechanism 13.
[0059] It should be understood that for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations shall fall within the protection scope of the appended claims of this application.
Claims
1. A powertrain, comprising: A housing, the housing comprising a crankcase and a gearbox connected to the crankcase; A crank-connecting rod mechanism, wherein the crank-connecting rod mechanism comprises a crankshaft, and the crankshaft is located in the crankcase; A speed change mechanism, wherein the speed change mechanism is at least partially located in the gearbox and is drivingly connected to the crankshaft; It is characterized in that The gearbox includes a gearbox, which is located on one side of the crankcase along the length direction of the powertrain, and the speed change mechanism includes a driving gear assembly, a driven gear assembly and a countershaft assembly located in the gearbox, and the driving gear assembly is drivingly connected to the countershaft assembly; The driving gear assembly includes a first helical gear, a driving bevel gear and a driving gear shaft, the first helical gear and the driving bevel gear are respectively located on both sides of the driving gear shaft, the first helical gear and the driving bevel gear are both fixedly connected to the driving gear shaft, the driven gear assembly includes a driven bevel gear, the countershaft assembly includes a second helical gear, the driving bevel gear is transmission-connected to the driven bevel gear, the first helical gear is transmission-connected to the second helical gear, and the axial force generated by the rotation of the first helical gear is opposite to the axial force generated by the rotation of the driving bevel gear.
2. The powertrain according to claim 1, characterized in that: The driving gear assembly also includes a limiting washer, a driving gear bearing, a locking nut, a driving sleeve and an active positioning bearing. The limiting washer, the driving gear bearing, the locking nut, the driving sleeve and the active positioning bearing are all located between the driving bevel gear and the first helical gear. The limiting washer, the driving gear bearing, the locking nut, the driving sleeve and the active positioning bearing are sequentially sleeved on the driving gear shaft. The axial force generated by the rotation of the driving bevel gear and the axial force generated by the rotation of the first helical gear act on both sides of the driving gear bearing respectively.
3. The powertrain according to claim 2, characterized in that: The gear transmission comprises an active bearing clamping portion and an active positioning clamping portion, the active gear bearing is clamped in the active bearing clamping portion, and the active positioning bearing is clamped in the active positioning clamping portion.
4. The powertrain according to claim 1, characterized in that: The speed change mechanism also includes a main shaft assembly located in the gear transmission, the main shaft assembly includes an output main shaft and a high-speed main shaft bevel gear fixedly connected to the output main shaft, the counter shaft assembly also includes a speed change counter shaft and a high-speed counter shaft bevel gear sleeved on the speed change counter shaft, the high-speed main shaft bevel gear is meshed with the high-speed counter shaft bevel gear, and the axial force generated by the rotation of the high-speed counter shaft bevel gear is opposite to the axial force generated by the rotation of the second bevel gear.
5. The powertrain according to claim 4, characterized in that: The layshaft assembly also includes a middle bearing and a parking gear sleeved on the speed-changing layshaft, the middle bearing is located between the high-gear layshaft helical gear and the second helical gear, the speed-changing layshaft includes a layshaft shoulder, the axial force generated by the rotation of the high-gear layshaft helical gear acts on one side of the middle bearing through the layshaft shoulder, and the axial force generated by the rotation of the second helical gear acts on the other side of the middle bearing through the parking gear.
6. The powertrain according to claim 5, characterized in that: The main shaft assembly also includes a low-gear main shaft bevel gear fixedly connected to the output main shaft, and the secondary shaft assembly also includes a low-gear secondary shaft bevel gear and an end bearing sleeved on the speed change secondary shaft, the low-gear main shaft bevel gear is meshed with the low-gear secondary shaft bevel gear, and the end bearing is clamped with the gear transmission case, and the axial force generated by the rotation of the low-gear secondary shaft bevel gear acts on the end bearing.
7. The powertrain according to claim 6, characterized in that: The main shaft assembly also includes a reverse gear main shaft gear fixedly connected to the output main shaft, the reverse gear main shaft gear is located between the low gear main shaft bevel gear and the high gear main shaft bevel gear along the axial direction of the output main shaft, and the reverse gear main shaft gear is arranged close to the high gear main shaft bevel gear.
8. The powertrain according to claim 6, characterized in that: The main shaft assembly also includes a main shaft bearing, and the gear transmission includes a main shaft clamping portion, and the main shaft bearing is clamped with the main shaft clamping portion, and the axial force generated by the rotation of the low-speed main shaft helical gear or the axial force generated by the rotation of the low-speed main shaft helical gear acts on the main shaft bearing.
9. The powertrain according to claim 7, characterized in that: The speed change mechanism also includes a reverse gear support shaft and a reverse gear transition gear, the countershaft assembly also includes a reverse gear countershaft gear, the reverse gear main shaft gear and the countershaft reverse gear transition gear are transmission-connected through the reverse gear transition gear, the reverse gear transition gear is sleeved on the reverse gear support shaft, the gear transmission box also includes a first support part and a second support part, one end of the reverse gear support shaft is connected to the first support part, and the other end of the reverse gear support shaft is connected to the second support part.
10. The powertrain according to claim 1, characterized in that: The driven gear assembly includes a front output shaft and a rear output shaft, both of which extend along the length direction of the powertrain, a rear end of the front output shaft is fixedly connected to a front end of the rear output shaft, the driven bevel gear is sleeved on the front output shaft and fixedly connected to the front output shaft, or the driven bevel gear is sleeved on the rear output shaft and fixedly connected to the rear output shaft.