Power assembly

Abstract

The invention discloses a power assembly which comprises an oil pan, a crankcase, a speed change mechanism and a crank connecting rod mechanism, and an oil storage space is formed in the oil pan; the crankcase is connected with the oil pan; the speed change mechanism comprises a main shaft which is arranged in the crankcase; the crank connecting rod mechanism comprises a crankshaft, and the crankshaft is arranged in the crankcase and is in transmission connection with the main shaft; an oil return channel communicated with the oil storage space is arranged on the crankcase, at least part of the oil return channel extends in the height direction of the power assembly, at least part of the oil return channel is located between the crankshaft and the main shaft, and the ratio of the displacement of the power assembly to the volume of the oil storage space is larger than or equal to 0.15 and smaller than or equal to 0.24. Through the arrangement, the lubricating oil is directly conveyed back to the oil storage space of the oil pan, so that the one-time circulation efficiency of the lubricating oil is improved, and the size of the oil pan can be reduced under the condition that the lubricating effect of the lubricating oil on the power assembly is met, so that the structural compactness of the power assembly is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power devices, in particular to a power assembly. Background Art

[0002] The powertrain is provided with oil passages so that the lubricating oil in the oil pan enters various mechanisms through the oil passages, thereby achieving lubrication of the various mechanisms. In the prior art, the layout of the oil passages often only considers how to make the oil passages lead to various mechanisms, but does not consider too much about the oil passages that return the lubricating oil to the oil pan, so that the efficiency of the lubricating oil returning to the oil pan is low, so that the oil pan requires a larger oil storage space, which in turn causes the structure of the powertrain to be less compact. Summary of the invention

[0003] In order to solve the deficiencies of the prior art, an object of the present invention is to provide a power assembly with a relatively compact structure.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A power assembly, comprising an oil pan, a crankcase, a speed change mechanism and a crank-connecting rod mechanism, wherein the oil pan is formed with an oil storage space; the crankcase is connected to the oil pan; the speed change mechanism comprises a main shaft, which is arranged in the crankcase; the crank-connecting rod mechanism comprises a crankshaft, which is arranged in the crankcase, and the crankshaft and the main shaft are drivingly connected; an oil return channel connected to the oil storage space is arranged on the crankcase, the oil return channel at least partially extends along the height direction of the power assembly, and the oil return channel is at least partially located between the crankshaft and the main shaft, and the ratio of the displacement of the power assembly to the volume of the oil storage space is greater than or equal to 0.15 and less than or equal to 0.24.

[0006] Furthermore, a ratio of a total length of the oil return passage to a height of the crankcase along a height direction of the powertrain is greater than or equal to 0.65 and less than or equal to 0.99.

[0007] Furthermore, the ratio of the flow rate of the oil return channel per unit time to the volume of the oil storage space is greater than or equal to 10 ml / (h*L) and less than or equal to 16 ml / (h*L).

[0008] Furthermore, the volume of the oil storage space is greater than or equal to 3L and less than or equal to 4.6L.

[0009] Furthermore, the uppermost end of the oil return passage is located above the main shaft.

[0010] Further, a ratio of the air pressure in the oil return passage to the air pressure in the oil pan is greater than or equal to 1 and less than or equal to 1.1.

[0011] Furthermore, the crankcase is formed with an oil and gas passage, the oil and gas passage is located on the upper side of the main shaft, a baffle unit is arranged in the oil and gas passage, and the baffle unit forms a maze pattern in the oil and gas passage.

[0012] Furthermore, the oil and gas passage is provided with an oil outlet and a gas outlet on the crankcase, the oil outlet is provided below the oil and gas passage, and the gas outlet is provided above the oil and gas passage.

[0013] Furthermore, the oil-gas channel is arranged above the oil return channel, and the oil output port is communicated with the oil return channel.

[0014] Furthermore, the oil return channel includes a first channel and a second channel that are connected to each other, the first channel is connected to the oil output port, and the second channel is connected to the oil storage space; the first channel extends obliquely downward from the back to the front, and the second channel extends basically along the height direction of the powertrain.

[0015] The above-mentioned power assembly can directly transport the lubricating oil back to the oil storage space of the oil pan through the oil return channel, thereby improving the efficiency of the first circulation of the lubricating oil, and further reducing the volume of the oil pan while satisfying the lubricating effect of the lubricating oil on the power assembly, so as to improve the structural compactness of the power assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the powertrain of this application.

[0017] Figure 2 An exploded diagram of the powertrain of this application.

[0018] Figure 3 This is a partial structural schematic diagram of the powertrain of this application.

[0019] Figure 4 This is a partial structural cross-sectional view of the powertrain of the present application.

[0020] Figure 5 This is a schematic diagram of the connection of the lubrication mechanism of the power assembly of the present application.

[0021] Figure 6 This is a schematic diagram of the structure of the shift fork of the power assembly of the present application.

[0022] Figure 7 This is a schematic diagram of the structure of the shift fork and the shift fork shaft of the power assembly of the present application.

[0023] Figure 8 This is a schematic diagram of the structure of the retaining ring, retaining ring groove and shaft body of the power assembly of the present application.

[0024] Fig. 9 This is a partial structural schematic diagram of the crankcase and oil pan of the power assembly of the present application.

[0025] Fig.10 This is a schematic diagram of the structure of the balance shaft mechanism of the powertrain of the present application.

[0026] Fig.11a This is a schematic diagram of the first structure of the oil inlet and oil outlet holes of the balance shaft of the present application.

[0027] Fig.11b This is a second structural schematic diagram of the oil inlet and oil outlet holes of the balance shaft of the present application.

[0028] Fig.12 This is a schematic diagram of the structure of the crankcase and balance shaft of the powertrain of the present application.

[0029] Fig.13 It is a partial structural cross-sectional view of the crankcase of the powertrain of the present application.

[0030] Fig.14 This is a schematic diagram of the structure of the crankcase and oil and gas passages of the power assembly of the present application. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the specific implementation modes of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the implementation modes of the present invention.

[0032] Figure 1 and Figure 2 A power assembly 100 is shown, which includes an outer shell 11, a crank connecting rod mechanism 12, a piston mechanism 13, a valve mechanism 14, an ignition device 15, an intake and exhaust mechanism 16, a speed change mechanism 17, and a lubrication mechanism 18 (refer to Figure 5 ) and the balance shaft mechanism 19 (refer to Figure 3 ). An accommodating space 111 is formed in the outer shell 11, and the crank-connecting rod mechanism 12, the piston mechanism 13, the valve mechanism 14, the ignition device 15, the intake and exhaust mechanism 16, the speed change mechanism 17, the lubrication mechanism 18, and the balance shaft mechanism 19 are all arranged in the accommodating space 111.

[0033] In this embodiment, the outer shell 11 includes a cylinder head cover 112, a cylinder head 113, a cylinder block 114, a crankcase 115 and an oil pan 116. The cylinder head cover 112, the cylinder head 113, the cylinder block 114, the crankcase 115 and the oil pan 116 are connected in sequence. Among them, a first accommodating space 1131 is formed in the cylinder head 113, and the ignition device 15, the valve mechanism 14 and the intake and exhaust mechanism 16 are at least partially arranged in the first accommodating space 1131. A second accommodating space 1141 is formed in the cylinder block 114, and the piston mechanism 13 is at least partially arranged in the second accommodating space 1141. Specifically, the cylinder block 114 is provided with a cylinder hole 1142 (refer to Figure 4), the piston mechanism 13 is at least partially disposed in the cylinder bore 1142. A third accommodating space 1151 is formed in the crankcase 115, and the crank-connecting rod mechanism 12, the speed change mechanism 17, the lubrication mechanism 18 and the balance shaft mechanism 19 are at least partially disposed in the third accommodating space 1151. The lubrication mechanism 18 is also at least partially disposed in the oil pan 116.

[0034] As an implementation method, the combustion chamber of the power assembly 100 is composed of the bottom of the cylinder head 113 and the top of the cylinder body 114. The crank-connecting rod mechanism 12 is connected to the piston mechanism 13 so that the movement of the piston mechanism 13 can drive the crank-connecting rod mechanism 12 to move. The valve mechanism 14 is in transmission connection with the crank-connecting rod mechanism 12, and the valve mechanism 14 is in abutment with the intake and exhaust mechanism 16. The movement of the crank-connecting rod mechanism 12 can also drive the valve mechanism 14 to move, so that the valve mechanism 14 can control the intake and exhaust of the intake and exhaust mechanism 16. Through the above arrangement, the normal operation of the power assembly 100 can be achieved.

[0035] Specifically, the crank-connecting rod mechanism 12 includes a crankshaft 121 and a connecting rod 122, and the crankshaft 121 and the piston mechanism 13 are connected through the connecting rod 122 to achieve power transmission between the crankshaft 121 and the piston mechanism 13. The valve mechanism 14 includes a camshaft assembly 141 and a timing assembly 142, and the crankshaft 121 and the camshaft assembly 141 are transmission-connected through the timing assembly 142, so that the crankshaft 121 can drive the camshaft assembly 141 to move. The intake and exhaust mechanism 16 includes an intake component 161 and an exhaust component 162. The camshaft component 141 includes a camshaft 1411, a first cam 1412 and a second cam 1413. The first cam 1412 and the second cam 1413 are both arranged on the camshaft 1411. The first cam 1412 abuts against the intake component 161, and the second cam 1413 abuts against the exhaust component 162. The camshaft 1411 is connected to the crankshaft 121 through the timing component 142, so that the crankshaft 121 can drive the first cam 1412 on the camshaft 1411 to control the intake of the intake component 161, and the crankshaft 121 can drive the second cam 1413 on the camshaft 1411 to control the exhaust of the exhaust component 162. The speed change mechanism 17 includes a main shaft 171, a secondary shaft 172, a shift fork shaft 173 and a shift fork 174. The main shaft 171 is respectively connected to the crankshaft 121 and the secondary shaft 172. The main shaft 171 receives power transmitted from the crankshaft 121 and transmits the power to the secondary shaft 172 through a meshing gear set, and then outputs the power to the outside through the secondary shaft 172. Figure 3 and Figure 4As shown, specifically, a plurality of pairs of mutually cooperating shift gears 177 are provided on the main shaft 171 and the secondary shaft 172, and power is transmitted through the shift gears 177. Among them, the shift fork 174 is at least partially sleeved on the shift fork shaft 173. A shift fork groove 1771 is provided on the shift gear 177, and the shift fork 174 is at least partially located in the shift fork groove 1771, so that the shift fork 174 can adjust the meshing relationship of the shift gear 177 so that the speed change mechanism 17 transmits power with different multiples of transmission ratios. The balance shaft mechanism 19 is transmission-connected to the crankshaft 121 to solve the dynamic balance problem when the crankshaft 121 rotates. In order to clearly illustrate the technical solution of the present application, it is also defined as follows: Figure 1 In the present application, the length direction of the powertrain 100 refers to the front, rear, left, right, top, and bottom. Figure 1 The front-to-rear direction in the diagram, the width direction of the powertrain 100 refers to Figure 1 The left and right directions in the figure, the height direction of the powertrain 100 refers to Figure 1 The up and down directions in .

[0036] like Figure 3 Shown ，As an implementation method, a projection plane 101 perpendicular to the axial direction of the secondary shaft 172 is defined. In the present application, the axis of the secondary shaft 172 extends substantially along the width direction of the powertrain 100, and therefore, the projection plane 101 is substantially perpendicular to the width direction of the powertrain 100. The projection of the rotation center of the crankshaft 121 along the axial direction of the secondary shaft 172 on the projection plane 101 is the first projection point, the projection of the axis of the main shaft 171 along the axial direction of the secondary shaft 172 on the projection plane 101 is the second projection point, the projection of the axis of the secondary shaft 172 along the axial direction of the secondary shaft 172 on the projection plane 101 is the third projection point, the line connecting the first projection point and the second projection point is the first line L1, the line connecting the second projection point and the third projection point is the second line L2, and the angle α1 formed by the first line L1 and the second line L2 is set to be greater than or equal to 60° and less than or equal to 90°. Further, the angle α1 formed by the first line L1 and the second line L2 is set to be greater than or equal to 68° and less than or equal to 82°. Furthermore, the angle α1 formed by the first connecting line L1 and the second connecting line L2 is set to be greater than or equal to 72° and less than or equal to 80°. Through the above setting, it is possible to avoid the angle α1 being too large, which may cause the distance between the secondary shaft 172 and the crankshaft 121 along the length direction of the power assembly 100 to be too large, thereby avoiding the distance between the secondary shaft 172 and the crankshaft 121 to be too large and increase the length of the power assembly 100 in the length direction; it is also possible to avoid the angle α1 being too small, which may cause interference between the secondary shaft 172 and the crankshaft 121, or avoid the angle α1 being too small, which may cause interference between the secondary shaft 172, the crankshaft 121 and other parts, or avoid the angle α1 being too small, which may cause the distance between the secondary shaft 172 and the crankshaft 121 along the height direction of the power assembly 100 to be too large, thereby reducing the size of the power assembly 100 in the length direction and the height direction, so as to improve the structural compactness of the power assembly 100.

[0037] As an implementation, the length of the first line L1 can also be limited. Specifically, the length of the first line L1 is set to be greater than or equal to 110 cm and less than or equal to 160 cm. Further, the length of the first line L1 is set to be greater than or equal to 125 cm and less than or equal to 145 cm. Furthermore, the length of the first line L1 is set to 136 cm. Through the above settings, it is possible to prevent the distance between the crankshaft 121 and the main shaft 171 from being too large, thereby increasing the length of the power assembly 100 in the length direction, thereby improving the structural compactness of the power assembly 100; it is also possible to prevent the distance between the crankshaft 121 and the main shaft 171 from being too small, thereby causing interference between the crankshaft 121, the main shaft 171 and other components.

[0038] Similarly, the line from the first projection point to the third projection point is the third line L3, and the length of the third line L3 is limited, which can also achieve the above beneficial effects. Specifically, the length of the third line L3 is set to be greater than or equal to 110 cm and less than or equal to 160 cm. Further, the length of the first line L1 is set to be greater than or equal to 125 cm and less than or equal to 145 cm. Further, the length of the first line L1 is set to 137 cm.

[0039] like Figure 3 As shown, as an implementation method, the lengths of the first line L1 and the third line L3 are substantially equal, and along the height direction of the powertrain 100, the axis of the crankshaft 121 and the axis of the secondary shaft 172 are substantially located on the same height plane. In other words, the first line L1, the second line L2 and the third line L3 form an isosceles triangle, and the second line L2 is the shortest side of the isosceles triangle. Specifically, the ratio of the length of the first line L1 to the length of the second line L2 is greater than or equal to 1.8 and less than or equal to 2.2, and further, the ratio of the length of the first line L1 to the length of the second line L2 is greater than or equal to 1.9 and less than or equal to 2.1; illustratively, the length of the first line L1 can also be twice that of the second line L2. Through the above-mentioned setting, it is possible to prevent the above-mentioned ratio from being too large, which would cause the distance between the main shaft 171 and the secondary shaft 172 to be too small, thereby avoiding interference between the main shaft 171, the secondary shaft 172 and other components; it is also possible to prevent the above-mentioned ratio from being too small, which would cause the distance between the main shaft 171 and the secondary shaft 172 to be too large, thereby improving the structural compactness of the main shaft 171 and the secondary shaft 172, and further improving the structural compactness of the powertrain 100.

[0040] like Figure 3 and Figure 4As shown, in order to further improve the compactness and space utilization of the powertrain 100, as an implementation method, the maximum distance between the axis of the secondary shaft 172 and the oil pan 116 along the height direction of the powertrain 100 is a first distance Q1, and the maximum distance between the axis of the secondary shaft 172 and the cylinder block 114 along the height direction of the powertrain 100 is a second distance Q2, and the ratio of the first distance Q1 to the second distance Q2 is greater than or equal to 0.28 and less than or equal to 0.42. Further, the ratio of the first distance Q1 to the second distance Q2 is greater than or equal to 0.33 and less than or equal to 0.37; exemplary, the ratio of the first distance Q1 to the second distance Q2 is 0.36. When defining the position of the secondary shaft 172, in addition to defining the maximum distance from the secondary shaft 172 to the cylinder block 114, the maximum distance between the secondary shaft 172 and the camshaft 1411 can also be defined; specifically, the maximum distance between the axis of the secondary shaft 172 and the camshaft 1411 along the height direction of the power assembly 100 is the third distance Q3, and the ratio of the first distance Q1 to the third distance Q3 is greater than or equal to 0.38 and less than or equal to 0.56. Further, the ratio of the first distance Q1 to the third distance Q3 is greater than or equal to 0.43 and less than or equal to 0.51; further, the ratio of the first distance Q1 to the third distance Q3 is greater than or equal to 0.45 and less than or equal to 0.49.

[0041] The maximum distance between the axis of the main shaft 171 and the oil pan 116 along the height direction of the power assembly 100 is a fourth distance Q4, the maximum distance between the axis of the main shaft 171 and the cylinder block 114 along the height direction of the power assembly 100 is a fifth distance Q5, and the ratio of the fourth distance Q4 to the fifth distance Q5 is greater than or equal to 0.74 and less than or equal to 1.10. Further, the ratio of the fourth distance Q4 to the fifth distance Q5 is greater than or equal to 0.82 and less than or equal to 1.02. Further, the ratio of the fourth distance Q4 to the fifth distance Q5 is greater than or equal to 0.87 and less than or equal to 0.97.

[0042] Through the above-mentioned arrangement, it is possible to avoid the distance between the main shaft 171, the secondary shaft 172 and the crankshaft 121 being too large, which would cause the space occupied by the main shaft 171, the secondary shaft 172 and the crankshaft 121 to be too large, thereby reducing the volume of the power assembly 100, which is beneficial to improving the structural compactness of the power assembly 100; it is also possible to avoid the distance between the main shaft 171, the secondary shaft 172 and the crankshaft 121 being too small, which would cause interference between the main shaft 171, the secondary shaft 172, the crankshaft 121 and other components, thereby facilitating the normal operation of the main shaft 171, the secondary shaft 172, the crankshaft 121 and other components, and improving the working stability of the main shaft 171, the secondary shaft 172 and the crankshaft 121.

[0043] Therefore, through the above-mentioned setting, the structure of the power assembly 100 can be made more compact while satisfying the normal operation of the power assembly 100. Specifically, the ratio of the height of the power assembly 100 along its height direction to the width along its width direction is greater than or equal to 0.9 and less than or equal to 1.37. More specifically, the ratio of the height of the power assembly 100 along its height direction to the width along its width direction is greater than or equal to 1.02 and less than or equal to 1.25. Furthermore, the ratio of the height of the power assembly 100 along its height direction to the width along its width direction can also be 1.13.

[0044] like Figure 5 As shown, as an embodiment, the lubrication mechanism 18 includes a filter 181, an oil pump 182, a pressure relief valve 183, an oil filter 184, an oil cooler 185, a main oil channel 186 and a sub-oil channel 187. The filter 181, the oil pump 182, the oil filter 184 and the oil cooler 185 are connected in sequence and arranged in the oil pan 116. Among them, the oil pump 182 extracts lubricating oil from the oil pan 116 and increases the pressure of the lubricating oil so that the lubricating oil has the power to flow upward. Specifically, an oil storage space is formed in the oil pan 116, and the oil pump 182 extracts lubricating oil from the oil storage space of the oil pan 116. The filter 181 arranged between the oil pump 182 and the oil pan 116 filters the particulate impurities of the lubricating oil to prevent the particulate impurities from entering the oil pump 182 and damaging the oil pump 182. The oil filter 184 is located between the oil pump 182 and the oil cooler 185, and is used to filter impurities in the lubricating oil again. The oil cooler 185 cools the lubricating oil so that the lubricating oil can take away the heat on the parts while lubricating the parts.

[0045] like Figure 5 As shown, the main oil passage 186 is connected to the oil cooler 185, and the main oil passage 186 is used to provide lubricating oil to the crank-connecting rod mechanism 12 and the valve mechanism 14. Specifically, there are N connecting rods 122, and the crankshaft 121 is provided with N+1 journals, and the 1st to N+1th journals are arranged in sequence; the main oil passage 186 provides lubricating oil to the N+1 journals respectively; and the lubricating oil output by the main oil passage 186 passes through the 1st to Nth journals to provide lubricating oil to the N connecting rods 122 respectively, and the remaining N+1th journal provides lubricating oil to the valve mechanism 14. Among them, N is an integer greater than or equal to 1; the 1st to Nth journals provide lubricating oil to the connecting rod journals of the N connecting rods 122 respectively.

[0046] Since the crankshaft 121 is also provided with a starting gear, which is provided on a side close to the first journal of the crankshaft 121, the first journal can also be provided to provide lubricating oil to the starting gear. Therefore, the main oil passage 186 provides more lubricating oil to the first journal than to any one of the second to the N+1th journals.

[0047] In addition, since the N+1th journal has no corresponding connecting rod 122, the lubricating oil moves through the N+1th journal to the camshaft 1411 and the tensioner in the powertrain 100 to lubricate the valve mechanism 14 and the tensioner. Specifically, a route for the N+1th journal to provide lubricating oil to the valve mechanism 14 branches off to provide lubricating oil to the tensioner.

[0048] For example, in a four-cylinder engine, four connecting rods 122 are provided, and five journals are provided on the crankshaft 121, with the first to fifth journals arranged in sequence; the main oil channel 186 provides lubricating oil to the five journals respectively; and the lubricating oil output by the main oil channel 186 passes through the first to fourth journals to provide lubricating oil to the connecting rod journals of the four connecting rods 122 respectively, and the remaining fifth journal provides lubricating oil to the valve mechanism 14. The lubricating oil provided by the main oil passage 186 to the first journal is more than the lubricating oil provided to any one of the second to fifth journals. The output diameter of the lubricating oil provided by the main oil passage 186 to the first journal is 6 mm, and the output diameter of the lubricating oil provided by the main oil passage 186 to the second to fourth journals is 5 mm. In addition, since the fifth journal does not have a corresponding connecting rod 122, it is set that the lubricating oil moves toward the camshaft 1411 after passing through the fifth journal, and the output diameter of the lubricating oil provided by the main oil passage 186 to the fifth journal is also set to 5 mm. Among them, the output diameter of the lubricating oil provided by the main oil passage 186 to the first journal refers to the inner diameter of the oil delivery hole of the lubricating oil provided by the main oil passage 186 to the first journal; the output diameter of the lubricating oil provided by the main oil passage 186 to the second to fourth journals refers to the inner diameter of the oil delivery hole of the lubricating oil provided by the main oil passage 186 to the second to fourth journals.

[0049] like Figure 5As shown, the sub-oil passage 187 includes a first sub-oil passage 1871 and a second sub-oil passage 1872. The first sub-oil passage 1871 is connected to the main oil passage 186, and the first sub-oil passage 1871 is used to provide lubricating oil to the speed change mechanism 17. As an embodiment, the first sub-oil passage 1871 is divided into two branch oil passages 188 to respectively provide lubricating oil to the main shaft 171 and the secondary shaft 172; and the two branch oil passages 188 are provided with throttle plugs 189, and the throttle plugs 189 provide lubricating oil to the secondary shaft 172. The second sub-oil passage 1872 is connected to the output end of the oil cooler 185, and the second sub-oil passage 1872 is used to provide lubricating oil to the piston mechanism 13. Specifically, the piston mechanism 13 includes a piston 131, and the second sub-oil passage 1872 is used to provide lubricating oil to the piston 131. It should be noted that the ratio of the output diameter of the lubricating oil provided by the main oil passage 186 to the journal and the output diameter of the lubricating oil provided by the second sub-oil passage 1872 to the piston 131 is greater than or equal to 4 and less than or equal to 6. For example, the output diameter of the lubricating oil provided by the main oil passage 186 to the journal is approximately 5 mm, and the output diameter of the lubricating oil provided by the second sub-oil passage 1872 to the piston 131 is 1 mm. The output diameter of the lubricating oil provided by the main oil passage 186 to the journal refers to the inner diameter of a single oil delivery hole for the main oil passage 186 to provide lubricating oil to the journal; the output diameter of the lubricating oil provided by the second sub-oil passage 1872 to the piston 131 refers to the inner diameter of the oil delivery hole for the second sub-oil passage 1872 to provide lubricating oil to the piston 131.

[0050] Through the above-mentioned arrangement, the lubrication mechanism 18 of the powertrain 100 of the present application is designed according to the structure of the outer shell 11 and the arrangement of the lubrication points, so that the oil channel diameter of the lubrication mechanism 18 is reasonably arranged, which is convenient for the diversion of the lubrication points and the processing of the lubrication mechanism 18; and by setting the throttle plug 189 in the branch oil channel 188, the lubrication and cooling requirements between the main shaft 171 and the secondary shaft 172 are further met.

[0051] like Figure 6 and Figure 7 As shown in the figure, as an implementation, the fork 174 includes a fork base 1741, a fork handle 1742, a fork head 1743 and a fork oil passage 1744. The fork base 1741 is sleeved on the fork shaft 173; the fork handle 1742 is arranged on the fork base 1741 and connected to the fork base 1741; the fork head 1743 is connected to the fork handle 1742, and the fork head 1743 is at least partially located in the fork groove 1771 of the shift gear 177 (refer to Figure 4); the fork oil passage 1744 is at least partially disposed in the fork handle 1742, the fork oil passage 1744 is connected to the fork shaft 173, and the fork oil passage 1744 passes through the fork head 1743 and is connected to the fork groove 1771. Through the above arrangement, the lubricating oil delivered to the fork shaft 173 can be delivered to the fork groove 1771 of the shift gear 177 through the fork oil passage 1744, thereby reducing the wear between the fork head 1743 and the fork groove 1771, which is beneficial to improving the service life of the fork head 1743 and the fork groove 1771, and further improving the service life of the power assembly 100.

[0052] Specifically, the shift fork oil passage 1744 has an oil inlet 1744a and an oil outlet 1744b, the oil outlet 1744b of the shift fork oil passage 1744 is set through the center of the shift fork head 1743, the oil inlet 1744a of the shift fork oil passage 1744 is set on the shift fork handle 1742, or the oil inlet 1744a of the shift fork oil passage 1744 is set on the shift fork base 1741. Through the above arrangement, the lubricating oil can be transported from the oil inlet 1744a to the shift fork oil passage 1744, and transported from the oil outlet 1744b to the shift fork groove 1771 of the shift gear 177, so as to improve the lubrication effect between the shift fork 174 and the shift fork groove 1771.

[0053] In this embodiment, the ratio of the length of the fork handle 1742 to the inner diameter of the fork oil passage 1744 is greater than or equal to 8 and less than or equal to 12. Further, the ratio of the length of the fork handle 1742 to the inner diameter of the fork oil passage 1744 is greater than or equal to 9 and less than or equal to 11. Furthermore, the ratio of the length of the fork handle 1742 to the inner diameter of the fork oil passage 1744 is 10.

[0054] In addition, in order to ensure the structural strength of the fork 174 while reducing the weight of the fork 174, the ratio of the thickness of the fork handle 1742 along the axial direction of the fork shaft 173 to the inner diameter of the fork oil passage 1744 is greater than or equal to 1.2 and less than or equal to 4. Further, the ratio of the thickness of the fork handle 1742 along the axial direction of the fork shaft 173 to the inner diameter of the fork oil passage 1744 is greater than or equal to 1.5 and less than or equal to 3. Furthermore, the ratio of the thickness of the fork handle 1742 along the axial direction of the fork shaft 173 to the inner diameter of the fork oil passage 1744 is greater than or equal to 1.8 and less than or equal to 2.5.

[0055] like Figure 6 and Figure 7As shown, the fork base 1741 is provided with a through hole 1741a, and the through hole 1741a is sleeved on the fork shaft 173. The inner wall of the through hole 1741a is at least partially concave to form an inner groove 1741b, and a fork oil chamber 1701 is formed between the groove bottom surface of the inner groove 1741b and the fork shaft 173. The fork oil chamber 1701 can store oil, and the fork oil chamber 1701 can also be connected to the fork oil passage 1744, so as to provide lubricating oil for the fork head 1743. Among them, the groove bottom surface of the inner groove 1741b refers to the inner surface of the inner groove 1741b away from the fork shaft 173.

[0056] As an implementation method, the inner groove 1741b is arranged in the middle section of the through hole 1741a, so that the two ends of the through hole 1741a can abut against the fork shaft 173, thereby improving the sleeve stability of the through hole 1741a and the fork shaft 173, and improving the working stability of the fork 174. In order to balance the stability of the fork 174 on the fork shaft 173 and the spatial volume of the fork oil chamber 1701, the ratio of the area of ​​the inner groove 1741b to the entire inner wall area of ​​the through hole 1741a is greater than or equal to 0.4 and less than or equal to 0.8. Further, the ratio of the area of ​​the inner groove 1741b formed by the inner concave of the inner wall of the through hole 1741a to the entire inner wall area of ​​the through hole 1741a is greater than or equal to 0.5 and less than or equal to 0.7. Furthermore, the ratio of the area of ​​the inner groove 1741b formed by the inner concave of the inner wall of the through hole 1741a to the entire inner wall area of ​​the through hole 1741a is greater than or equal to 0.55 and less than or equal to 0.65.

[0057] As an implementation manner, the fork oil passage 1744 passes through the fork base 1741 , and the fork oil passage 1744 is in communication with the inner groove 1741 b , so that the lubricating oil in the inner groove 1741 b can be transported to the fork groove 1771 through the fork oil passage 1744 .

[0058] In the present application, the roughness of the bottom surface of the inner groove 1741b is greater than or equal to the roughness of the inner wall of the non-recessed portion of the through hole 1741a, so that the bottom surface of the inner groove 1741b can be simply polished or not polished, so as to simplify the polishing process of the through hole 1741a, reduce costs, and improve the smoothness of the movement of the fork 174.

[0059] like Figure 8 As shown, the speed change mechanism 17 further includes a shaft 175 and a rotating member 176, wherein the rotating member 176 is disposed on the shaft 175 and is rotatably connected to the shaft 175. It should be noted that the shaft 175 generally refers to shafts at various locations in the powertrain 100, and is not limited to the speed change mechanism 17, that is, any structure that satisfies the requirement that a rotating member rotatably connected to the shaft 175 is disposed on the shaft 175 is within the scope of protection of this application. The rotating member 176 may be a gear or other component.

[0060] In the present application, the shaft body 175 and the rotating member 176 disposed in the speed change mechanism 17 are taken as an example for description. Specifically, the shaft body 175 further includes a retaining ring groove 1751, and a retaining ring 1752 is disposed on the shaft body 175. The retaining ring 1752 is disposed in the retaining ring groove 1751, and the retaining ring 1752 is used to limit the axial movement of the rotating member 176 along the shaft body 175. In this embodiment, the retaining ring groove 1751 includes a first end 1751d and a second end 1751e, and the first end 1751d and the second end 1751e are distributed along the axial direction of the shaft body 175. The bottom surface 1751a of the retaining ring groove 1751 is an inclined surface inclined from the first end 1751d to the second end 1751e, so that the outer diameter of the retaining ring groove 1751 changes within a preset range, and the outer diameter of the first end 1751d is smaller than the outer diameter of the second end 1751e. The inner diameter of the retaining ring 1752 is larger than the outer diameter of the first end 1751d and smaller than the outer diameter of the second end 1751e, so that the retaining ring 1752 can only move toward the first end 1751d during operation, but cannot move toward the second end 1751e. The rotating member 176 is arranged away from the first end 1751d, and the rotating member 176 is arranged close to the second end 1751e. Through the above-mentioned arrangement, when the rotating member 176 is in a working state, that is, when the rotating member 176 and the shaft body 175 rotate relative to each other, the retaining ring 1752 will not move toward the rotating member 176, so that the rotating member 176 and the retaining ring 1752 will not interfere with each other, so as to reduce or prevent the friction between the rotating member 176 and the retaining ring 1752, so as to improve the working stability of the rotating member 176, and further help to reduce the power loss of the rotating member 176, so as to improve the transmission efficiency of the rotating member 176.

[0061] More specifically, the ratio of the outer diameter X1 of the first end 1751d to the outer diameter X2 of the second end 1751e is greater than or equal to 0.76 and less than or equal to 0.98. Further, the ratio of the outer diameter X1 of the first end 1751d to the outer diameter X2 of the second end 1751e is greater than or equal to 0.86 and less than or equal to 0.97, or the ratio of the outer diameter X1 of the first end 1751d to the outer diameter X2 of the second end 1751e can also be 0.96. Through the above-mentioned arrangement, it is possible to prevent the ratio of the outer diameters of the retaining ring groove 1751 at the first end 1751d and the second end 1751e from being too large, resulting in a preset range being too small, thereby preventing the retaining ring 1752 from moving in a too small range, resulting in friction between the retaining ring 1752 and the rotating member 176, thereby improving the working stability of the retaining ring 1752 and the rotating member 176; it is also possible to prevent the ratio of the outer diameters of the retaining ring groove 1751 at the first end 1751d and the second end 1751e from being too small, resulting in a preset range being too large, thereby preventing the retaining ring 1752 from moving in a too large range, resulting in the retaining ring 1752 being unable to limit the axial displacement of the rotating member 176 along the shaft body 175, thereby improving the limiting effect of the retaining ring 1752 on the rotating member 176.

[0062] As an embodiment, the bottom surface 1751a of the retaining ring groove 1751 is an inclined plane to facilitate the movement of the retaining ring 1752 in the retaining ring groove 1751. The side wall of the retaining ring groove 1751 close to the first end 1751d is defined as the groove side surface 1751b, and a transition portion is formed between the bottom surface 1751a of the retaining ring groove 1751 and the groove side surface 1751b, and the transition portion is set as a rounded transition. Specifically, the center angle α3 of the transition portion is greater than or equal to 90° and less than or equal to 130°; further, the center angle α3 of the transition portion is greater than or equal to 100° and less than or equal to 120°. Exemplarily, the center angle α3 of the transition portion is 115°, so as to facilitate the placement of the retaining ring 1752 in the retaining ring groove 1751 and define the position of the retaining ring 1752. In this embodiment, the groove side surface 1751 b is a plane that is substantially perpendicular to the axis of the shaft body 175 , so that the plane can serve as an abutment surface of the retaining ring 1752 , thereby facilitating the abutment stability of the retaining ring 1752 .

[0063] In addition, the bottom surface 1751a of the retaining ring groove 1751 extends substantially along the preset plane, and the angle γ formed between the preset plane and the axis of the shaft body 175 is greater than or equal to 15° and less than or equal to 45°. Further, the angle γ formed between the preset plane and the axis of the shaft body 175 is greater than or equal to 20° and less than or equal to 30°; further, the angle γ formed between the preset plane and the axis of the shaft body 175 is 25°. Through the above arrangement, it is possible to avoid the angle γ being too large, which may result in the contact area between the retaining ring 1752 and the bottom surface 1751a of the retaining ring groove 1751 being too small, thereby avoiding the unstable contact between the retaining ring 1752 and the retaining ring groove 1751, so as to improve the working stability of the retaining ring 1752; it is also possible to avoid the angle γ being too small, which may result in the retaining ring 1752 being unable to move freely to the side with the smallest diameter of the retaining ring groove 1751, thereby avoiding the retaining ring 1752 interfering with the parts arranged on the side with the largest diameter of the retaining ring groove 1751.

[0064] The ratio of the width X3 of the retaining ring groove 1751 along the axial direction of the shaft body 175 to the thickness X4 of the retaining ring 1752 along its own axial direction is greater than or equal to 1.1 and less than or equal to 1.7. Further, the ratio of the width X3 of the retaining ring groove 1751 along the axial direction of the shaft body 175 to the thickness X4 of the retaining ring 1752 along the axial direction of the retaining ring 1752 is greater than or equal to 1.2 and less than or equal to 1.6. Further, the ratio of the width X3 of the retaining ring groove 1751 along the axial direction of the shaft body 175 to the thickness X4 of the retaining ring 1752 along the axial direction of the retaining ring 1752 is 1.4. Through the above arrangement, it is possible to avoid the retaining ring groove 1751 being too wide and wasting space, and it is also possible to avoid the retaining ring groove 1751 being too narrow and affecting the arrangement of the retaining ring 1752.

[0065] In this embodiment, there is a gap between the rotating member 176 and the retaining ring 1752. When observed from the radial direction of the shaft 175, the rotating member 176 and the retaining ring groove 1751 at least partially overlap, thereby making the structure of the rotating member 176 and the retaining ring groove 1751 more compact, thereby improving the structural compactness of the speed change mechanism 17 when the retaining ring 1752 does not rub against the rotating member 176.

[0066] like Figure 5 and Fig. 9 As shown, the sub-oil channel 187 also includes a third sub-oil channel 1873. The oil cooler 185 is connected to the main oil channel 186, the second sub-oil channel 1872 and the third sub-oil channel 1873. The third sub-oil channel 1873 extends along the height direction of the power assembly 100 and passes through the balance shaft 191, so that the third sub-oil channel 1873 can provide lubricating fluid to the balance shaft 191.

[0067] like Fig. 9 and Fig.10 As shown, the balancing shaft 191 is provided with an oil inlet 1911, an oil outlet 1912, a counterweight 1913 and a lubrication hole 1914. Specifically, the oil inlet 1911 serves as an inlet for lubricating oil delivered to the balancing shaft 191. One end of the oil outlet 1912 is connected to the oil inlet 1911, and one end of the oil outlet 1912 away from the oil inlet 1911 is connected to the opening of the third sub-oil passage 1873. A projection plane 1901 perpendicular to the axial direction of the balancing shaft 191 is defined, and the projection of the end of the oil outlet 1912 away from the oil inlet 1911 on the projection plane 1901 along the axial direction of the balancing shaft 191 is a first projection, and the projection of the opening of the third sub-oil passage 1873 on the projection plane 1901 along the axial direction of the balancing shaft 191 is a second projection, and the maximum length of the first projection along the circumferential direction of the balancing shaft 191 is greater than the maximum length of the second projection along the circumferential direction of the balancing shaft 191. During the assembly process of the balancing shaft 191, if there is an assembly error in the balancing shaft 191, the above arrangement can prevent the oil outlet hole 1912 and the third sub-oil channel 1873 from being blocked due to the assembly error, thereby facilitating the flow of lubricating oil. The counterweight 1913 is arranged on the balancing shaft 191 and is rotatably connected to the balancing shaft 191. Specifically, the counterweight 1913 is rotatably connected to the balancing shaft 191 through a bearing; the lubricating hole 1914 is connected to the oil inlet hole 1911, and the output port of the lubricating hole 1914 faces the counterweight 1913, or the output port of the lubricating hole 1914 faces the balancing shaft 191 in contact with the counterweight 1913, so that the lubricating oil can be delivered to the counterweight 1913 or the balancing shaft 191 in contact with the counterweight 1913 through the lubricating hole 1914, thereby improving the lubrication effect on the balancing shaft mechanism 19.

[0068] As shown in FIG. 11 , two different communication modes between the oil inlet 1911 and the oil outlet 1912 are shown. Fig.11a As shown, as an implementation method, the oil inlet 1911 and the oil outlet 1912 are directly connected. Fig.11b As shown, as another implementation, a connecting hole 1916 is further provided between the oil inlet hole 1911 and the oil outlet hole 1912 , and the connecting hole 1916 connects the oil inlet hole 1911 and the oil outlet hole 1912 , respectively.

[0069] In addition, as an implementation method, the end surface of the oil outlet hole 1912 near the oil inlet hole 1911 is an arc surface, and the oil outlet hole 1912 forms a temporary oil cavity relative to the third sub-oil channel 1873, so that lubricating oil can be stored in the temporary oil cavity. Among them, the arc center of the end surface of the oil outlet hole 1912 near the oil inlet hole 1911 can be away from the axis of the balance shaft 191 to improve the oil storage capacity of the temporary oil cavity. In this embodiment, the center of the end surface of the oil outlet hole 1912 near the oil inlet hole 1911 is connected to the oil inlet hole 1911, so that during the rotation of the balance shaft 191, the lubricating oil can smoothly move from the temporary oil cavity to the third sub-oil channel 1873.

[0070] As an implementation, the ratio of the maximum length of the first projection along the circumferential direction of the balancing shaft 191 to the maximum length of the second projection along the circumferential direction of the balancing shaft 191 is greater than or equal to 1 and less than or equal to 4. Further, the ratio of the maximum length of the first projection along the circumferential direction of the balancing shaft 191 to the maximum length of the second projection along the circumferential direction of the balancing shaft 191 is greater than or equal to 1.5 and less than or equal to 3.5. Exemplarily, the ratio of the maximum length of the first projection along the circumferential direction of the balancing shaft 191 to the maximum length of the second projection along the circumferential direction of the balancing shaft 191 is greater than or equal to 3. Through the above settings, it is possible to avoid the above ratio being too large to cause the oil outlet hole 1912 to be too large to affect the structural strength of the balancing shaft 191; it is also possible to avoid the above ratio being too small to cause the oil outlet hole 1912 to be too small, thereby avoiding the oil outlet hole 1912 to be too small to affect the delivery of lubricating oil; it is also possible to avoid the above ratio being too large to cause the oil outlet hole 1912 to be too large to cause waste of materials, thereby saving resources, and being conducive to improving processing efficiency and reducing processing difficulty.

[0071] In addition to the limitation of the circumferential size of the oil outlet hole 1912, the maximum width of the oil outlet hole 1912 along the axial direction of the balance shaft 191 is greater than or equal to the maximum width of the opening of the third sub-oil channel 1873 along the axial direction of the balance shaft 191, which is more conducive to oil storage and lubricating oil output.

[0072] like Fig.10 and Fig.12As shown, the balancing shaft 191 is also provided with a limiting groove 1915, which is arranged around the outer surface of the balancing shaft 191; the crankcase 115 is provided with a connecting hole 1156 and a limiting member 1151, and the limiting member 1151 passes through the connecting hole 1156 and is at least partially arranged in the limiting groove 1915, and the axial direction of the balancing shaft 191 is limited by the cooperation of the limiting member 1151 and the limiting groove 1915. The limiting groove 1915 and the oil outlet hole 1912 are respectively arranged at both ends of the balancing shaft 191 to ensure that the structural strength of both ends of the balancing shaft 191 is uniform.

[0073] like Fig.13 As shown, corresponding to the main oil passage 186, the first sub-oil passage 1871, the second sub-oil passage 1872 and the third sub-oil passage 1873 in the lubricating mechanism 18, the lubricating mechanism 18 further includes an oil return passage 1152 for returning the lubricating oil to the oil pan 116, the oil return passage 1152 is arranged in the crankcase 115, the oil return passage 1152 extends substantially along the height direction of the power assembly 100, the oil return passage 1152 is communicated with the oil storage space of the oil pan 116, and the oil return passage 1152 is at least partially located between the crankshaft 121 and the main shaft 171. Specifically, the oil return passage 1152 is at least partially located in the area between the crankshaft position 1154 accommodating the crankshaft 121 and the main shaft position 1155 accommodating the main shaft 171. Through the above-mentioned arrangement, the lubricating oil can be directly transported back to the oil storage space of the oil pan 116, thereby improving the efficiency of the first circulation of the lubricating oil. Further, while satisfying the lubricating effect of the lubricating oil on the power assembly 100, the volume of the oil pan 116 can be reduced to improve the structural compactness of the power assembly 100.

[0074] As an implementation, the ratio of the displacement of the power assembly 100 to the volume of the oil storage space of the oil pan 116 is greater than or equal to 0.15 and less than or equal to 0.24. Specifically, the ratio of the displacement of the power assembly 100 to the volume of the oil storage space of the oil pan 116 is greater than or equal to 0.17 and less than or equal to 0.22. More specifically, the ratio of the displacement of the power assembly 100 to the volume of the oil storage space of the oil pan 116 is 0.2. Through the above arrangement, the performance requirements of the power assembly 100 can be met while reducing the volume of the oil storage space of the oil pan 116, thereby making the structure of the power assembly 100 more compact and making the performance of the power assembly 100 higher. In addition, through the above-mentioned setting, it can be avoided that the above-mentioned ratio is too large, resulting in the lubricating oil in the oil storage space being unable to meet the displacement requirement of the powertrain 100; it can also be avoided that the above-mentioned ratio is too small, resulting in the volume of the oil pan 116 being too large, thereby preventing the volume of the powertrain 100 from being too large, and then the structural compactness of the powertrain 100 can be improved while meeting the displacement requirement of the powertrain 100.

[0075] Specifically, the ratio of the flow rate of the oil return channel 1152 per unit time to the volume of the oil storage space is greater than or equal to 10 ml / (h*L) and less than or equal to 16 ml / (h*L). More specifically, the ratio of the flow rate of the oil return channel 1152 per unit time to the volume of the oil storage space is greater than or equal to 12 ml / (h*L) and less than or equal to 14 ml / (h*L). Optionally, the ratio of the flow rate of the oil return channel 1152 per unit time to the volume of the oil storage space is 13 ml / (h*L). Through the above arrangement, the volume of the oil pan 116 can be reduced while satisfying the lubricating effect of the lubricating oil on the power assembly 100, so as to improve the structural compactness of the power assembly 100.

[0076] In this embodiment, the volume of the oil storage space of the oil pan 116 is greater than or equal to 3L and less than or equal to 4.6L. Specifically, the volume of the oil storage space of the oil pan 116 is greater than or equal to 3.4L and less than or equal to 4.2L. More specifically, the volume of the oil storage space of the oil pan 116 can also be 3.8L. Through the above configuration, it is possible to avoid the structural redundancy of the power assembly 100 caused by the excessive volume of the oil storage space of the oil pan 116 while satisfying the lubricating effect of the lubricating oil on the power assembly 100, so as to improve the structural compactness of the power assembly 100; it is also possible to avoid the oil storage space of the oil pan 116 being too small to meet the lubrication requirements of the power assembly 100.

[0077] As an implementation method, the uppermost end of the oil return channel 1152 is located above the main shaft 171 to improve the delivery efficiency of the lubricating oil return. Specifically, the ratio of the total length Q6 of the oil return channel 1152 and the height Q7 of the crankcase 115 along the height direction of the powertrain 100 is greater than or equal to 0.65 and less than or equal to 0.99. Fig.13 The length of the dashed line with an arrow in the middle, the dashed arrow indicates the direction of the lubricating oil flow. More specifically, the ratio of the total length Q6 of the return oil channel 1152 and the height Q7 of the crankcase 115 along the height direction of the powertrain 100 is greater than or equal to 0.73 and less than or equal to 0.9. Optionally, the ratio of the total length Q6 of the return oil channel 1152 and the height Q7 of the crankcase 115 along the height direction of the powertrain 100 can also be 0.82. Through the above arrangement, it is possible to prevent the total length of the return oil channel 1152 from being too long to reduce the return efficiency of the lubricating oil, and it is also possible to prevent the total length of the return oil channel 1152 from being too short to avoid other components inside the crankcase 115, thereby preventing the return oil channel 1152 from interfering with other components inside the crankcase 115.

[0078] As an implementation, the ratio of the air pressure in the oil return channel 1152 to the air pressure in the oil pan 116 is greater than or equal to 1 and less than or equal to 1.1. Specifically, the ratio of the air pressure in the oil return channel 1152 to the air pressure in the oil pan 116 is greater than or equal to 1.03 and less than or equal to 1.07. More specifically, the ratio of the air pressure in the oil return channel 1152 to the air pressure in the oil pan 116 can also be 1.05 or 1.01. Through the above arrangement, the balance of the air pressure in the oil return channel 1152 and the air pressure in the oil pan 116 can be achieved, thereby preventing the power assembly 100 from being unstable due to the imbalance of air pressure between the two, thereby improving the working stability of the power assembly 100.

[0079] like Fig.14 As shown, the crankcase 115 is formed with an oil-gas passage 1153, which is located on the upper side of the main shaft 171 to collect lubricating oil after lubricating the components in the crankcase 115. The oil-gas passage 1153 is located above the oil return passage 1152, and the exhaust gas separated by the oil-gas passage 1153 is discharged from the oil-gas passage 1153, and the lubricating oil separated by the oil-gas passage 1153 flows back to the oil pan 116 along the oil return passage 1152.

[0080] As an embodiment, a baffle unit 1153a is provided in the oil and gas passage 1153, and the baffle unit 1153a forms a maze pattern in the oil and gas passage 1153 to facilitate oil and gas separation. Specifically, the oil and gas passage 1153 is provided with an oil outlet and a gas outlet on the crankcase 115, and the oil outlet is provided below the oil and gas passage 1153, and the oil outlet is connected to the oil return passage 1152 to facilitate the delivery of lubricating oil to the oil return passage 1152. The gas outlet is provided above the oil and gas passage 1153 to facilitate the discharge of exhaust gas. In this embodiment, the crankcase 115 constitutes the oil and gas passage 1153 by two parts, so that the oil and gas passage 1153 can be easily installed and the processing of the oil and gas passage 1153 is also convenient.

[0081] In this embodiment, the oil return channel 1152 includes a first channel 1152a and a second channel 1152b which are connected to each other. The first channel 1152a is connected to the oil outlet, and the second channel 1152b is connected to the oil storage space of the oil pan 116, so that the lubricating oil can flow back from the first channel 1152a to the oil storage space of the oil pan 116 through the second channel 1152b.

[0082] The first channel 1152a extends obliquely downward from the back to the front, and the second channel 1152b extends substantially along the height direction of the power assembly 100, so that the first channel 1152a can avoid the components inside the crankcase 115 such as the main shaft 171, and the length of the second channel 1152b can be shorter, so as to improve the return efficiency of the lubricating oil. In the present application, the total length Q6 of the oil return channel 1152 is the total length of the first channel 1152a and the second channel 1152b.

[0083] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A powertrain, comprising: An oil pan, wherein the oil pan is formed with an oil storage space; a crankcase connected to the oil pan; A speed change mechanism, the speed change mechanism comprising a main shaft, the main shaft being disposed in the crankcase; A crank-connecting rod mechanism, wherein the crank-connecting rod mechanism comprises a crankshaft, the crankshaft is arranged in the crankcase, and the crankshaft is drivingly connected to the main shaft; It is characterized in that The crankcase is provided with an oil return channel connected to the oil storage space, the oil return channel at least partially extends along the height direction of the power assembly, and the oil return channel is at least partially located between the crankshaft and the main shaft, and the ratio of the displacement of the power assembly to the volume of the oil storage space is greater than or equal to 0.15 and less than or equal to 0.

24.

2. The powertrain according to claim 1, characterized in that: A ratio of a total length of the oil return passage to a height of the crankcase along a height direction of the powertrain is greater than or equal to 0.65 and less than or equal to 0.

99.

3. The powertrain according to claim 1, characterized in that: The ratio of the flow rate of the oil return channel per unit time to the volume of the oil storage space is greater than or equal to 10 ml / (h*L) and less than or equal to 16 ml / (h*L).

4. The powertrain according to claim 3, characterized in that: The volume of the oil storage space is greater than or equal to 3L and less than or equal to 4.6L.

5. The powertrain according to claim 1, characterized in that: The uppermost end of the oil return passage is located above the main shaft.

6. The powertrain according to claim 1, characterized in that: A ratio of the air pressure in the oil return passage to the air pressure in the oil pan is greater than or equal to 1 and less than or equal to 1.

1.

7. The powertrain according to claim 1, characterized in that: The crankcase is formed with an oil and gas passage, and the oil and gas passage is located on the upper side of the main shaft. A baffle unit is arranged in the oil and gas passage, and the oil and gas passage is formed into a maze pattern through the baffle unit.

8. The powertrain according to claim 7, characterized in that: The oil and gas passage is provided with an oil outlet and a gas outlet on the crankcase, the oil outlet is provided below the oil and gas passage, and the gas outlet is provided above the oil and gas passage.

9. The powertrain according to claim 8, characterized in that: The oil-gas channel is arranged above the oil return channel, and the oil output port is communicated with the oil return channel.

10. The powertrain according to claim 8, characterized in that: The oil return channel includes a first channel and a second channel that are connected to each other, the first channel is connected to the oil output port, and the second channel is connected to the oil storage space; the first channel extends obliquely downward from the back to the front, and the second channel extends basically along the height direction of the powertrain.

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