CN212985391U

CN212985391U - All-terrain vehicle and engine and crankcase thereof

Info

Publication number: CN212985391U
Application number: CN202021329834.4U
Authority: CN
Inventors: 不公告发明人
Original assignee: Nine Intelligent Changzhou Tech Co Ltd
Current assignee: Nine Intelligent Changzhou Tech Co Ltd
Priority date: 2019-11-04
Filing date: 2020-07-08
Publication date: 2021-04-16
Anticipated expiration: 2030-07-08
Also published as: WO2021088897A1; CN212985392U

Abstract

The utility model discloses an all-terrain vehicle and engine and crankcase thereof, the crankcase includes: a first side box body; the first side box body is connected with the first side box body, and the first box cover is arranged on one side, far away from the second side box body, of the first side box body; and the motor mounting cover is mounted on one side of the second side box body, which is far away from the first side box body. Therefore, the crankcase is reasonable in design, the crankshaft can be effectively supported through the first side box body, the second side box body and the first case cover, the installation reliability of the crankshaft can be guaranteed, the motor installation cover can play a role in installing the motor, the power performance of the all-terrain vehicle can be improved, and the emission of harmful gas can be reduced.

Description

All-terrain vehicle and engine and crankcase thereof

Technical Field

The utility model belongs to the technical field of the vehicle technique and specifically relates to an all-terrain vehicle and engine and crankcase thereof are related to.

Background

In the related art, the all-terrain vehicle is generally driven by a single power source, which is usually a fuel engine or a power motor. If the power source is a fuel engine, the vehicle generally has insufficient power under the working condition of low rotating speed of the engine; meanwhile, because the engine needs to participate in working under all working conditions, the mixed gas is not fully combusted in the process of changing the working conditions at low rotating speed, the heat efficiency is low, the fuel consumption is high, and the content of harmful gas in tail gas is high; if the power source is a power motor, the vehicle has the advantages of no exhaust gas discharge, low noise, simple structure and the like in the driving process, but has the defects of short driving range, high battery cost, long charging time, short battery service life, high maintenance cost and the like.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, an object of the present invention is to provide a crankcase, which is reasonable in design, and can mount a motor under the condition of effective supporting bearings, so as to improve the power performance of the all-terrain vehicle.

The utility model discloses an engine is further proposed.

The utility model discloses a still further an all terrain vehicle has been provided.

According to the utility model discloses a crankcase, include: a first side box body; the first side box body is connected with the first side box body, and the first box cover is arranged on one side, far away from the second side box body, of the first side box body; and the motor mounting cover is mounted on one side of the second side box body, which is far away from the first side box body.

Therefore, the crankcase is reasonable in design, the crankshaft can be effectively supported through the first side box body, the second side box body and the first case cover, the installation reliability of the crankshaft can be guaranteed, the motor installation cover can play a role in installing the motor, the power performance of the all-terrain vehicle can be improved, and the emission of harmful gas can be reduced.

In some examples of the invention, the first side box is provided with a first bearing, the second side box is provided with a second bearing, the first case lid is provided with a third bearing, the motor mounting lid is provided with a first through hole.

In some examples of the invention, the first bearing, the second bearing and the third bearing are sliding bearings.

The utility model discloses an in some examples, first bearing the second bearing with the third bearing all is provided with the oil groove and the oilhole that are linked together, first side box the second side box with first case lid is corresponding be provided with the oil circuit of oilhole intercommunication.

The utility model discloses an in some examples, second side box is provided with and is used for the installation the first mounting hole of second bearing, the interior week of first mounting hole is formed with first inlet port, the second bearing is formed with first oilhole and the first oil groove that is linked together, first oilhole with first inlet port is corresponding, first oil groove be formed at the inner peripheral surface of second bearing.

The utility model discloses an in some examples, first mounting hole department is provided with the nozzle opening, the second bearing is provided with the second oilhole, the second oilhole with the nozzle opening intercommunication, the exit end of nozzle opening is towards the piston bottom of engine, the nozzle opening is one at least.

In some examples of the present invention, the first bearing is formed with a second oil groove and a third oil hole that are communicated, the second oil groove being a non-annular oil groove.

In some examples of the present invention, the third bearing is formed with a third oil groove and a fourth oil hole that are linked together, the third oil groove being a non-annular oil groove.

An engine according to the present invention includes: the crankcase; and the cylinder body is arranged at the upper part of the crankcase.

In some examples of the invention, the engine has a cylinder block having a central plane, and a combined plane of the first side case and the second side case is not coplanar with the central plane.

According to the utility model discloses an all-terrain vehicle, include: the engine; and the motor is arranged on one axial side of the engine.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic illustration of a hybrid powertrain according to an embodiment of the present invention;

FIG. 2 is an exploded view of the engine and continuously variable transmission;

FIG. 3 is an exploded view of the hybrid powertrain shown in FIG. 1 at the electric machine;

FIG. 4 is an exploded view of the motor;

FIG. 5 is an exploded view of the crankcase of the engine;

FIG. 6 is a schematic view of a second side case and crankshaft;

FIG. 7 is an exploded view of the crankcase;

FIG. 8 is an exploded view of the crankcase;

FIG. 9 is a schematic view of a second bearing;

fig. 10 is a schematic view of a first bearing.

Reference numerals:

a hybrid powertrain 1000;

an engine 100; a crankshaft 10; an external spline 11; a crankcase 20;

a motor mounting cover 30; a receiving groove 31; a second bearing hole 32;

a first side case 40; a first bearing 41; a second oil sump 411; the third oil hole 412;

a second side case 50; a second bearing 51; the first oil hole 511; a first oil sump 512; the second oil hole 513;

a first mounting hole 52; a first oil inlet hole 521; an injection hole 522;

a first cover 60; a third bearing 61;

a piston 70;

a motor 200; a motor case 210; a housing hole 211; a motor cover 220; a through hole 221; a first bearing hole 222;

a stator 230; a convex ring 231; a rotor 240; a first rotor bearing 241; a second rotor bearing 242;

an outlet end 250; a wire outlet box cover 260; a gasket 270; an air bag 280; a connecting tube 281; a motor shaft 290;

a continuously variable transmission 300; the high-low range transmission 400.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

A hybrid powertrain 1000 according to an embodiment of the present invention is described below with reference to fig. 1 to 10, the hybrid powertrain 1000 being applied in a vehicle, specifically, the vehicle further includes: the hybrid power assembly 1000 is arranged in the power cabin of the frame. The vehicle may be an all terrain vehicle.

As shown in fig. 1 to 2, a hybrid powertrain 1000 according to an embodiment of the present invention may include: engine 100 and motor 200, motor 200 is disposed on one side of engine 100 in the axial direction, i.e. the left and right direction shown in fig. 1, motor 200 may be disposed on the right side of engine 100, and the left side thereof may be correspondingly disposed with a transmission, which may be a continuously variable transmission 300.

The traditional all-terrain vehicle is a pure fuel vehicle, while the all-terrain vehicle disclosed by the invention is a hybrid vehicle, and the hybrid vehicle can select a proper power mode according to actual needs, for example, when the road condition is good, a driver can select the engine 100 or the motor 200 as a power source, when the road condition is poor and the power of the engine 100 is insufficient, the driver can simultaneously select the engine 100 and the motor 200 as the power source, so that the power performance of the all-terrain vehicle can be effectively improved, effective guarantee can be provided for passing through poor road conditions, when the battery electric quantity is low, the driver can select the engine 100 as the power source, and when the fuel is low, the driver can select the motor 200 as the power source. Motor 200 may also function to recover energy, for example, when the vehicle is parked, the power generated by engine 100 may be recovered by motor 200, that is, motor 200 may be used not only as a motor but also as a generator.

Therefore, by arranging the hybrid power assembly 1000 composed of the engine 100 and the motor 200, the power performance of the all-terrain vehicle can be improved, and a proper power source can be selected according to the working condition and the road condition, so that the energy consumption can be reduced, the energy can be saved, and the emission of harmful gas can be reduced. In addition, the battery that supplies power to the motor 200 does not need to be continuously discharged for a long time, so that the service life of the battery can be extended.

As shown in fig. 2 and 3, the engine 100 includes a crankshaft 10 and a crankcase 20, the crankshaft 10 is mounted to the crankcase 20, and the crankcase 20 includes: and a motor mounting cover 30, and a first shaft end (i.e., a right end) of the crankshaft 10 extends out of the motor mounting cover 30. The engine 100 of the present invention can play a role of installing the motor 200 by providing the motor installation cover 30 at one side of the crankcase 20, so that the motor 200 can be integrated at one side of the engine 100, the integration level of the hybrid power assembly 1000 can be improved, and the occupied space of the hybrid power assembly 1000 can be reduced.

As shown in fig. 3, the motor 200 includes: motor casing 210 is installed between motor installation cover 30 and motor cover 220, stator 230 is fixed in motor casing 210, rotor 240 is arranged on the inner periphery of stator 230, rotor 240 can rotate relative to stator 230, rotor 240 is fixed on motor shaft 290, and motor shaft 290 is connected with the first axial end of crankshaft 10, so that rotor 240 and the first axial end of crankshaft 10 can be ensured to rotate synchronously. That is to say, the motor housing 210 can be fixed on the motor mounting cover 30, the motor cover 220 can be fixed on the motor housing 210 again, and the stator 230 is fixed in the motor housing 210, so that the main structure of the motor 200 can be fixed on one side of the crankcase 20 of the engine 100, thereby ensuring the connection reliability of the engine 100 and the motor 200, and the motor 200 is simple and reliable to install.

The rotor 240 is connected to the crankshaft 10 via the motor shaft 290 and rotates synchronously, so that when any one of the engine 100 and the motor 200 is used as a power source, the power can be transmitted to the wheels via the transmission system, in other words, the engine 100 and the motor 200 can share the transmission system, thereby reducing the modification of the vehicle and the development cost of the vehicle. It should be noted that, when engine 100 is in operation, crankshaft 10 may drive rotor 240 to rotate synchronously, and at this time, a part of power of engine 100 may be converted into electric energy by motor 200 and transmitted to the battery, and the battery may store the part of electric energy, so as to reduce energy waste. When the motor 200 operates, the motor 200 may transmit power through the crankshaft 10.

According to an alternative embodiment of the present invention, as shown in fig. 2 and 3, a receiving groove 31 opened toward the stator 230 is formed in the motor mounting cover 30, the motor housing 210 is provided with a receiving hole 211, the receiving hole 211 communicates with and corresponds to the receiving groove 31, a first portion of the stator 230 is received in the receiving groove 31, and a second portion of the stator 230 is received in the receiving hole 211. That is, the motor mounting cover 30 not only can serve to mount the motor 200, but also can serve as a cover plate on one side of the motor 200, and a portion of the stator 230 is also accommodated therein, so that the axial dimension of the hybrid powertrain 1000 can be effectively reduced, the stator 230 can be conveniently mounted and fixed, and the axial dimension of the motor case 210 can be reduced.

Alternatively, the outer circumferential surface of the stator 230 is interference-fitted with the accommodation hole 211. The interference fit mode can ensure that the stator 230 can be firmly installed in the accommodating hole 211, the installation reliability between the stator 230 and the motor casing 210 can be ensured, and the interference fit mode is simple and easy to implement.

Further, as shown in fig. 3 and 4, the outer circumferential surface of the stator 230 is provided with a protruding ring 231 protruding outward, the axial dimension of the protruding ring 231 is smaller than the axial dimension of the receiving hole 211, and the outer circumferential surface of the protruding ring 231 is in interference fit with the receiving hole 211. That is, the stator 230 is engaged with the motor housing 210 by providing the protruding ring 231, so that the structure of the stator 230 can be simplified, the weight of the stator 230 can be reduced, and the installation reliability of the stator 230 can be ensured.

According to an embodiment of the present invention, as shown in fig. 3 and 4, the motor 200 may further include a wire outlet end 250 and a wire outlet box cover 260, the wire outlet end 250 is connected to the stator 230, the wire outlet box cover 260 is disposed on a side of the motor cover 220 away from the motor casing 210, the motor cover 220 is provided with a through hole 221, a receiving space of the wire end 250 is defined between the motor cover 220 and the wire outlet box cover 260, and the wire outlet end 250 extends out of the motor cover 220 and is received in the receiving space. The winding wire end of the stator 230 is connected to the wire outlet 250, and the wire outlet 250 is accommodated in the accommodating space, so that the motor cover 220 and the wire outlet box cover 260 can jointly protect the wire outlet 250. The outlet box cover 260 also has the function of sealing the motor 200, so that the structural sealing performance of the motor 200 can be ensured.

Further, as shown in fig. 3 and 4, the motor 200 may further include: the sealing gasket 270, the sealing gasket 270 is disposed between the motor cover 220 and the outlet box cover 260, as shown in fig. 4, the sealing gasket 270 is disposed at a joint surface of the motor cover 220 and the outlet box cover 260. The gasket 270 may act as a seal to better protect the outlet end 250 and the stator 230. The gasket 270 may act as a waterproof as the vehicle may be subjected to partial wading conditions. The sealing pad 270 may be a rubber pad.

As shown in fig. 3 and 4, the motor cover 220 is provided with a first bearing hole 222, the rotor 240 is provided with a first rotor bearing 241 fitted in the first bearing hole 222, and a packing 270 is disposed around the receiving space and the first bearing hole 222. Accordingly, the gasket 270 is appropriately sized, so that the difficulty in manufacturing the gasket 270 can be reduced, and the gasket 270 can effectively seal the inner space of the motor 200.

Referring to fig. 3 and 4, the motor mounting cover 30 is detachably mounted to the crankcase 20, the motor housing 210 is detachably mounted to the motor mounting cover 30, the motor cover 220 is detachably mounted to the motor housing 210, and the outlet cover 260 is detachably mounted to the motor cover 220. That is, the motor 200 is integrally disposed on one side of the crankcase 20, so that the assembly and disassembly are convenient, the subsequent further maintenance and replacement of parts are convenient, and the maintenance cost of the hybrid power assembly 1000 can be reduced.

Optionally, a first shaft end of the crankshaft 10 is splined to a shaft end of the motor shaft 290. By means of spline fit, the crankshaft 10 and the rotor 240 can move synchronously, and power can be transmitted between the crankshaft and the rotor smoothly.

Specifically, as shown in fig. 4, the first shaft end of the crankshaft 10 is provided with an external spline 11, the shaft end of the motor shaft 290 is provided with an internal spline and a second rotor bearing 242, the motor mounting cap 30 is provided with a second bearing hole 32, the internal spline is engaged with the external spline 11, and the second bearing hole 32 is engaged with the second rotor bearing 242. That is, the shaft end of the motor shaft 290 is sleeved on the first shaft end of the crankshaft 10, then the internal spline and the external spline 11 are matched with each other, and the rotor 240 is also matched in the second bearing hole 32 through the second rotor bearing 242, so that the supporting and transmission reliability of the shaft end of the motor shaft 290 and the shaft end of the crankshaft 10 can be ensured, and the structural reliability of the hybrid power assembly 1000 can be improved.

According to an embodiment of the present invention, as shown in fig. 3 and 4, the motor 200 may further include: an air bag 280, the air bag 280 is connected to the motor cover 220, and the air bag 280 communicates with the inner space of the motor case 210. The air bag 280 can expand and contract, when the temperature in the motor 200 is high, part of gas can enter the air bag 280, and the air bag 280 can play a role in stabilizing the working state of the motor 200, so that the working stability of the motor 200 can be ensured, and the working performance of the motor 200 can be improved.

The motor cover 220 is provided with an air hole, a connection pipe 281 is connected between the air hole and the air bag 280, the connection pipe 281 is bent toward the upper portion of the crankcase 20, and the air bag 280 is disposed on the upper portion of the crankcase 20. The air bag 280 thus provided can reasonably utilize the surrounding space of the crankcase 20, so that the hybrid power assembly 1000 occupies a smaller space and is reasonable in overall layout.

As shown in fig. 1 and 2, a second shaft end of the crankshaft 10 protrudes to the left of the crankcase 20, and the second shaft end of the crankshaft 10 is connected to an input portion of the continuously variable transmission 300. The continuously variable transmission 300 thus arranged can reasonably utilize the space on the other side of the engine 100, and can improve the integration level of the hybrid powertrain 1000.

Also, as shown in fig. 2, the hybrid powertrain 1000 further includes: high-low gear transmission 400, high-low gear transmission 400 sets up in crankcase 20, and high-low gear transmission 400 sets up with bent axle 10 interval moreover, and high-low gear transmission 400 includes: the input shaft and the output shaft, between which a transmission gear set is provided, are connected with the output part of the continuously variable transmission 300. By arranging the high-low gear transmission 400 in the crankcase 20, the internal space of the crankcase 20 can be reasonably utilized, and the combination of the continuously variable transmission 300 and the high-low gear transmission 400 can make the output power of the hybrid power assembly 1000 have various choices, so that the power output capacity of the hybrid power assembly 1000 can be improved.

The crankcase 20 of the engine 100 according to the embodiment of the invention will be described in detail below with reference to the drawings.

As shown in fig. 5 to 8, the crankcase 20 of the engine 100 according to the embodiment of the invention may include a first side case 40, a second side case 50, a first case cover 60, and the motor mounting cover 30 described above, the first side case 40 is provided with a first bearing 41, the second side case 50 is provided with a second bearing 51, the second side case 50 and the first side case 40 are axially disposed opposite to each other, the first case cover 60 is disposed on a side of the first side case 40 away from the second side case 50, that is, the first case cover 60 is disposed on a left side of the first side case 40, and the second side case 50 is disposed on a right side of the first side case 40.

The first cover 60 is provided with a third bearing 61, the third bearing 61 corresponds to the first bearing 41, and the motor mounting cover 30 is mounted on the second side case 50 at a side away from the first side case 40, i.e., the motor mounting cover 30 is mounted on the right side of the second side case 50. And the motor mounting cover 30 is provided with a first through hole corresponding to the second bearing 51, i.e., the second bearing hole 32 described above.

That is, the crankcase 20 is mainly composed of the first side case 40, the second side case 50, the first case cover 60, and the motor mounting cover 30, wherein the first side case 40 and the second side case 50 define an internal mounting space of the crankcase 20, and the crankshaft 10 and the high-low transmission 400 are both disposed in the internal mounting space, so that the crankcase 20 is structurally reliable, and the arrangement of a plurality of components can be facilitated.

The first shaft end of the crankshaft 10 can correspondingly penetrate through the second bearing 51 and the second bearing hole 32 to be connected with the motor shaft 290, and the second shaft end of the crankshaft 10 can correspondingly penetrate through the first bearing 41 and the third bearing 61, so that the crankcase 20 arranged in this way can effectively support the crankshaft 10, the installation reliability of the crankshaft 10 in the crankcase 20 can be ensured, and the working reliability of the engine 100 can be ensured. Wherein a first axial end of the crankshaft 10 has a first sliding surface which fits within the second bearing 51 and a second axial end of the crankshaft 10 has a second sliding surface which fits within the first bearing 41 and the third bearing 61.

Optionally, the first bearing 41, the second bearing 51 and the third bearing 61 are all sliding bearings. The sliding bearing has the characteristics of stable and reliable work and no noise, the sliding surface is separated by lubricating oil under the condition of liquid lubrication without direct contact, the friction loss and the surface abrasion can be greatly reduced, and the oil film also has certain vibration absorption capacity. By using the integral type sliding bearing, the crankshaft 10 can be effectively supported, and the difficulty in mounting the bearing can be reduced.

According to an embodiment of the present invention, the first bearing 41, the second bearing 51 and the third bearing 61 are provided with oil grooves and oil holes communicating with each other, and the first side case 40, the second side case 50 and the first cover 60 are provided with oil passages communicating with the oil holes. That is, the oil path may supply oil to the oil groove through the oil hole, so that the sliding surface of the crankshaft 10 may be effectively lubricated, friction loss may be reduced, and the smoothness of rotation of the crankshaft 10 may be improved.

Specifically, as shown in fig. 7 to 9 in combination, the second side case 50 is provided with a first mounting hole 52 for mounting the second bearing 51, a first oil inlet hole 521 is formed in an inner periphery of the first mounting hole 52, a first oil hole 511 and a first oil groove 512 communicating with each other are formed in the second bearing 51, the first oil hole 511 corresponds to the first oil inlet hole 521, and the first oil groove 512 is formed in an inner peripheral surface of the first bearing 41. The lubricating oil can enter the first oil groove 512 from the first oil inlet 521 and the first oil hole 511, and the lubricating oil in the first oil groove 512 can effectively lubricate the first shaft end of the crankshaft 10, so that the crankshaft 10 can smoothly rotate.

Further, as shown in fig. 6 and 8, an oil injection hole 522 is provided at the first mounting hole 52, at least one, and optionally two, oil injection holes 52 are provided, the second bearing 51 is provided with a second oil hole 513, the second oil hole 513 is communicated with the oil injection hole 522, and an exit end of the oil injection hole 522 faces the bottom of the piston 70 of the engine 100. The oil spray hole 522 may spray the lubricant oil to the bottom of the piston 70 by using oil pressure, so as to lubricate the piston 70, reduce the abrasion of the piston 70, prolong the service life of the piston 70, and improve the operational reliability of the engine 100. Wherein the second oil hole 513 and the first oil hole 511 are provided at an interval in the circumferential direction of the first bearing 41.

Alternatively, as shown in fig. 10, the first bearing 41 is formed with a second oil groove 412 and a third oil hole 411, the third bearing 61 is formed with a third oil groove and a fourth oil hole, and the second oil groove 412 and the third oil groove are non-annular oil grooves. Therefore, the first bearing 41 and the third bearing 61 can also play a role in lubricating the second shaft end of the crankshaft 10, the oil film pressure at the oil groove can be uniform through the non-annular oil groove, and the lubricating effect is good.

Alternatively, as shown in fig. 5, the engine 100 has a block having a central plane perpendicular to the axial direction of the crankcase 20, and the combined plane of the first side case 40 and the second side case 50 is not coplanar with the central plane. By disposing the joint plane of the first side case 40 and the second side case 50 to be not coplanar with the central plane, the axial dimensions of the first side case 40 and the second side case 50 can be made to gradually approach each other, the difference in the axial dimensions between the two can be reduced, and the difficulty in molding the first side case 40 and the second side case 50 can be reduced.

Specifically, the axial dimension of the first side case 40 and the axial dimension of the second side case 50 may be the same. Therefore, the first side case 40 and the second side case 50 can be manufactured by using close molds, so that the difficulty in manufacturing the first side case 40 and the second side case 50 can be reduced.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A crankcase, comprising:

a first side box body;

the first box cover is arranged on one side of the first side box body, which is far away from the second side box body;

and the motor mounting cover is mounted on one side of the second side box body, which is far away from the first side box body.

2. The crankcase of claim 1, wherein the first side case is provided with a first bearing, the second side case is provided with a second bearing, the first case cover is provided with a third bearing, and the motor mounting cover is provided with a first through hole.

3. The crankcase of claim 2, wherein the first bearing, the second bearing, and the third bearing are all plain bearings.

4. The crankcase according to claim 2, wherein the first bearing, the second bearing, and the third bearing are each provided with an oil groove and an oil hole that communicate with each other, and the first side case body, the second side case body, and the first case cover are respectively provided with an oil passage that communicates with the oil hole.

5. The crankcase according to claim 4, wherein the second side case is provided with a first mounting hole for mounting the second bearing, an inner periphery of the first mounting hole is formed with a first oil inlet hole, the second bearing is formed with a first oil hole and a first oil groove communicating with each other, the first oil hole corresponds to the first oil inlet hole, and the first oil groove is formed in an inner periphery of the second bearing.

6. The crankcase of claim 5, wherein the first mounting hole is provided with an oil injection hole, the second bearing is provided with a second oil hole, the second oil hole is communicated with the oil injection hole, an emergent end of the oil injection hole faces the bottom of a piston of the engine, and at least one oil injection hole is formed.

7. The crankcase of claim 4, wherein the first bearing is formed with a second oil groove and a third oil hole communicating with each other, the second oil groove being a non-annular oil groove.

8. The crankcase of claim 4, wherein the third bearing is formed with a third oil groove and a fourth oil hole that communicate with each other, the third oil groove being a non-annular oil groove.

9. An engine, comprising:

the crankcase of any one of claims 1-8;

and the cylinder body is arranged at the upper part of the crankcase.

10. The engine of claim 9, wherein the engine has a block with a central plane, and wherein a plane of juncture of the first side case and the second side case is not coplanar with the central plane.

11. An all-terrain vehicle, comprising:

the engine of claim 9 or 10;

and the motor is arranged on one axial side of the engine.