Patent Description:
A power steering system is a system that assists a driver in adjusting a vehicle direction, and can reduce a force required by the driver to operate a steering wheel. There are many types of power systems, among which REPS (Rack parallel electronic power steering system, rack-assisted electric power steering gear) has been widely used in medium and high-end vehicle models in recent years due to its large power range and good noise characteristics.

A working principle of the REPS is as follows: When the driver operates the steering wheel, the steering wheel drives a steering shaft to rotate. The steering shaft and a steering rod are connected through a gear and a rack engaged with each other. The steering shaft rotates to drive the steering rod to move leftward or rightward, to drive a wheel to turn leftward or rightward. A torque angle sensor can collect steering information transferred by the steering wheel and transfer the steering information to a controller. Alternatively, an autonomous driving center sends steering response requirement information, and transfers the steering response requirement information to a controller. After receiving the information, the controller performs calculation and processing, and then sends motor current control information, so that a motor outputs a corresponding torque and rotational speed/angle. The motor uses a transmission belt to connect a drive pulley on an output shaft of the motor and a driven pulley on the steering rod. The driven pulley and the steering rod form a screw transmission structure, decelerating and increasing a torque through the transmission belt. The driven pulley converts a rotational torque into an axial force of the steering rod, to implement vehicle steering.

In the REPS, belt transmission has advantages of stable transmission, low noise, and a high transmission ratio, but because the transmission belt is made of rubber and additives, the belt has specific elasticity. Excessively tight assembly may cause an excessively large friction force and serious wear. Excessively loose assembly is likely to produce noise and cause slipping. Therefore, tension of the transmission belt needs to be adjusted to an appropriate range.

<CIT> discloses a motor-driven steering system capable of easily adjusting tension. The motor-driven steering system comprises a driven pulley connected to a driving pulley of the motor through a belt, a gear housing for surrounding the driven pulley, a motor housing rotatably connected to the gear housing by means of a hinge shaft, and a guide formed at one side portion of the gear housing. The distance between the driving pulley and the driven pulley is adjusted by rotating the motor housing relative to the gear housing.

This application provides a transmission apparatus, to adjust tension of a transmission belt, so that wear on the transmission belt caused by excessively large tension can be avoided, or noise and slipping caused by excessively small tension can be avoided.

A first aspect of this application provides a transmission apparatus disclosing the features of claim <NUM>.

The tension pulley disposed on the adjustment pin abuts against the transmission belt, so that when the drive pulley rotates around the adjustment pin as a center for adjustment, a position between the tension pulley and the drive pulley may be changed. This can change a path through which the transmission belt passes when connecting the drive pulley and the driven pulley, to change a length of the transmission belt and adjust the tension of the transmission belt.

In a third possible implementation of the first aspect, the outer circumferential surface of the tension pulley abuts against an outer circumferential surface of the transmission belt. In this case, the path through which the transmission belt passes when connecting the drive pulley and the driven pulley may be changed by using the tension pulley, so that a distance between the transmission belt located on two sides of a part between the drive pulley and the driven pulley is shorter, and both a radian and a corresponding belt contact angle of contact between the transmission belt and both the drive pulley and the driven pulley are larger. This increases a contact area between the transmission belt and both the drive pulley and the driven pulley, improves a maximum static friction force between the transmission belt and both the drive pulley and the driven pulley, reduces a possibility of slipping between the transmission belt and both the drive pulley and the driven pulley, and reduces wear of the transmission belt. In addition, the motor rotates relative to the housing, and the drive pulley is adjusted away from/towards the driven pulley. In this case, when the transmission belt is extended/shortened, the tension pulley correspondingly moves towards/far away from a connection line between a center of the drive pulley and a center of the driven pulley, so that the tension pulley can tighten/loosen the transmission belt. This can increase an adjustment range of the tension of the transmission belt, reduce an angle at which the motor needs to rotate when the tension of the transmission belt is adjusted, and reduce space required for adjusting positions of the motor and the drive pulley.

In a fourth possible implementation of the first aspect, the axis of the drive pulley, an axis of the driven pulley, and the axis of the adjustment pin are in parallel, and a relative position between the axis of the driven pulley and the axis of the adjustment pin remains unchanged. This can ensure that when the drive pulley rotates around the adjustment pin, the transmission belt is normally connected to both the drive pulley and the driven pulley, and belt transmission is normally performed regardless of misalignment between the drive pulley and the driven pulley.

In a fifth possible implementation of the first aspect, the transmission apparatus further includes a first motor and a housing. The first motor is configured to drive the drive pulley, and the first motor is mounted on the housing by using the adjustment pin. Therefore, the first motor is mounted on the housing by using the adjustment pin. When the first motor is mounted, the first motor may be positioned by using the adjustment pin, so that the first motor is fastened to the housing. The adjustment pin can further improve connection strength between the first motor and the housing. When the first motor and the housing are fastened by a bolt, if most bolts fail due to fracture or detachment caused by vibration or the like, even if only one bolt is connected between the first motor and the housing, the adjustment pin may fasten the first motor, to prevent the first motor from rotating around the only one bolt.

In a sixth possible implementation of the first aspect, the first motor further includes a first chamber, and the adjustment pin further includes a through hole. A first end of the through hole is located in the first chamber, a second end of the through hole is located outside the first motor, and the first chamber is connected to an outside of the first motor through the through hole. Therefore, when the first motor rotates, air in the first chamber may enter and exit the first chamber through the through hole, to reduce air pressure fluctuation in the first chamber when the first motor rotates and reduce noise generated when the first motor rotates. The first chamber is connected to the outside of the first motor through the through hole, so that air heated in the first chamber due to operation of the first motor can be exchanged with air outside the first motor through the through hole, improving heat dissipation efficiency of the first motor.

In a seventh possible implementation of the first aspect, the housing is enclosed to form a second chamber, and the drive pulley, the driven pulley, and the adjustment pin are accommodated in the second chamber. That the first chamber is connected to an outside of the first motor through the through hole specifically includes: The first chamber is connected to the second chamber through the through hole. In this case, the first chamber and the second chamber can be connected through the through hole, so that air tightness detection can be simultaneously performed in the first chamber and the second chamber. This can simplify production steps, accelerate a production speed and improve production efficiency.

In an eighth possible implementation of the first aspect, an axis of the through hole coincides with the axis of the adjustment pin. This can simplifier processing of the through hole, and improve production efficiency. The adjustment pin can be directly processed and manufactured by using a pipe material, so that a drilling operation is not required during production. This simplifies a production procedure and improves production efficiency.

In a ninth possible implementation of the first aspect, the adjustment pin further includes a positioning end face, and the positioning end face is configured to abut against the housing. In this case, the positioning end face abuts against the housing, so that positioning can be implemented when the adjustment pin is mounted on the housing, to facilitate mounting of the adjustment pin.

In a tenth possible implementation of the first aspect, the adjustment pin is fixedly connected to the housing. In this case, stability of fitting between the adjustment pin and the housing can be implemented without increasing a thickness of the housing. This can reduce the thickness of the housing, save a material, and reduce a weight of the housing. In addition, after the first motor is mounted on the housing, the drive shaft needs to pass through the housing before the drive pulley is mounted. Reducing the thickness of the housing may correspondingly reduce a length of the drive shaft, so that a length of the drive shaft exposed from the first motor is shorter. Therefore, rigidity and durability of the drive shaft are improved, and transmission of the drive shaft is more stable.

In an eleventh possible implementation of the first aspect, the first motor further includes a first fastening part, and the first motor is fixedly connected to the housing by using the first fastening part. In this case, the first motor can be conveniently fastened to the housing by using the first fastening part.

In a twelfth possible implementation of the first aspect, that the first motor further includes a first fastening part specifically includes: The motor includes at least one bolt hole; and the first motor is relatively fastened to the housing through a bolt connection. In this case, a fixed connection may be implemented by using a bolt, to facilitate mounting and removal.

In a thirteenth possible implementation of the first aspect, the transmission apparatus further includes a second motor, and the second motor and the first motor jointly drive the drive pulley. This can increase a driving force, and the first motor and the second motor may be mutually redundant, improving stability of the transmission apparatus.

A second aspect of this application provides a transmission apparatus including the adjustment pin as defined in claim <NUM>, where a motor is hinged to a housing by using the adjustment pin, and the adjustment pin is staggered with a drive shaft of the motor. A drive pulley is disposed on the drive shaft. A driven pulley is disposed at a position corresponding to the drive pulley on the housing. The drive pulley is connected to the driven pulley by using a transmission belt. After a motor rotates relative to the housing to adjust tension of the transmission belt, the motor is fixedly connected to the housing. In this case, the motor is hinged to the housing by using the adjustment pin, so that the motor can rotate relative to the housing. The adjustment pin is staggered with the drive shaft of the motor. Therefore, when the motor rotates relative to the housing, the drive shaft may rotate by using the adjustment pin as an axle, so that the drive pulley rotates by using the adjustment pin as an axle. The driven pulley is disposed on the housing. Therefore, when the motor rotates relative to the housing, a distance between the drive pulley and the driven pulley may be adjusted, and a magnitude of tension of the transmission belt between the drive pulley and the driven pulley may be adjusted. In addition, the motor is hinged to the housing by using the adjustment pin. Therefore, when the motor is mounted on the housing, the motor may be positioned by using the adjustment pin, so that the motor is fastened to the housing. The adjustment pin can further improve connection strength between the motor and the housing. When the motor and the housing are fastened by a bolt, if most bolts fail due to fracture or detachment caused by vibration or the like, even if only one bolt is connected between the motor and the housing, the adjustment pin may fasten the motor, to prevent the motor from rotating around the only one bolt.

The tension pulley is further included. The tension pulley is disposed on the adjustment pin, and the tension pulley is configured to abut against the transmission belt. In this case, the tension pulley disposed on the adjustment pin abuts against the transmission belt, so that when the motor rotates around the adjustment pin as a center for adjustment, a position between the tension pulley and the drive pulley may be changed. This can change a path through which the transmission belt passes when connecting the drive pulley and the driven pulley, to change a length of the transmission belt and adjust the tension of the transmission belt.

In a third possible implementation of the second aspect, there is a first chamber inside the motor, and there is a second chamber inside the housing. The drive pulley, the driven pulley, and the transmission belt are disposed in the second chamber. The adjustment pin further includes a through hole. The through hole is provided in the adjustment pin and is used to connect the first chamber and the second chamber. In this case, the first chamber and the second chamber can be connected through the through hole, so that air tightness detection can be simultaneously performed in the first chamber of the motor and the second chamber of the housing. In addition, the first chamber is connected to the second chamber through the through hole. Therefore, in comparison with a separate second chamber, space is larger. This can reduce pressure fluctuation occurring in the second chamber when the motor rotates, and reduce noise generated when the motor rotates. The first chamber is connected to the second chamber through the through hole, so that air heated in the second chamber due to operation of the motor can be exchanged with air inside the first chamber through the through hole, improving heat dissipation efficiency of the motor.

In a fourth possible implementation of the second aspect, a positioning end face is further included. The positioning end face is configured to abut against the housing. In this case, the positioning end face abuts against the housing, so that positioning can be implemented when the adjustment pin is mounted on the housing, to facilitate mounting of the adjustment pin.

A third aspect of this application provides a transmission apparatus adjustment method, where the transmission apparatus is the transmission apparatus in any one of the fifth to the thirteenth possible implementations of the first aspect. The method includes: adjusting a rotation angle of a drive pulley rotating around an adjustment pin; and when tension of a transmission belt is greater than a first tension threshold, fixedly connecting a first motor to a housing. Therefore, the drive pulley may be controlled to rotate around the adjustment pin, to adjust a distance between the drive pulley and a driven pulley and adjust a magnitude of tension of the transmission belt between the drive pulley and the driven pulley.

In a possible implementation of the third aspect, before the adjusting a rotation angle of a drive pulley rotating around an adjustment pin, the method further includes: disconnecting a fixed connection between the first motor and the housing.

A further aspect of this application provides a vehicle, including the transmission apparatus in the possible implementations of the first aspect.

These aspects and another aspect of this application will be clearer and easier to understand in descriptions of the following (a plurality of) embodiments.

The following further describes features of this application and a relationship between the features with reference to the accompanying drawings. The accompanying drawings are all examples, and some features are not shown in actual proportions. In addition, in some accompanying drawings, common features that are not mandatory for this application in the field of this application may be omitted. Alternatively, additional features that are not mandatory for this application are not shown. A combination of the features shown in the accompanying drawings is not intended to limit this application. In addition, in this specification, content referred to by same reference numerals is also the same. Specific accompanying drawings are described as follows:.

<NUM>: housing; <NUM>: oblong hole; <NUM>: motor; <NUM>: drive shaft; <NUM>: drive pulley; <NUM>: driven pulley; <NUM>: transmission belt; <NUM>: boss; <NUM>: circular hole; <NUM>: tension pulley; <NUM>: vehicle; <NUM>: steering system; 20a: front wheel steering; 20b: rear wheel steering; <NUM>: steering wheel; <NUM>: first steering shaft; <NUM>: second steering shaft; <NUM>: third steering shaft; <NUM>: gear; <NUM>: housing; <NUM>: second chamber; <NUM>: steering rod; <NUM>: rack; <NUM>: REPS; <NUM>: motor; <NUM>: drive shaft; <NUM>: first chamber; <NUM>: shell; <NUM>: first fastening part; <NUM>: connection hole; <NUM>: positioning rack; <NUM>: fastening plate; <NUM>: positioning pinion; <NUM>: drive pulley; <NUM>: driven pulley; <NUM>: bearing; <NUM>: transmission belt; <NUM>: adjustment pin; <NUM>: fixed end; <NUM>: adjustment end; <NUM>: positioning end face; <NUM>: tension pulley; <NUM>: through hole; 2765a: first end; 2765b: second end.

Solution <NUM>, which is not covered by the claims, adjusts tension of a transmission belt by adjusting a center distance between a drive pulley and a driven pulley.

<FIG> is a schematic diagram of a structure of a transmission apparatus in solution <NUM>. As shown in <FIG>, three oblong holes <NUM> are provided on a housing <NUM>, and a bolt may pass through the oblong hole <NUM>, to fasten a motor <NUM> to the housing <NUM>. The bolt may move along and inside the oblong hole <NUM>, to adjust a position of the motor <NUM> on the housing <NUM>. In this case, a distance between a drive pulley <NUM> disposed on a drive shaft <NUM> of the motor <NUM> and a driven pulley <NUM> disposed on the housing <NUM> may be adjusted, to adjust tension of a transmission belt <NUM> used to connect the drive pulley <NUM> and the driven pulley <NUM>.

<FIG> is another schematic diagram of a structure of a transmission apparatus in solution <NUM>. As shown in <FIG>, a cylindrical boss <NUM> is disposed on a shell of a motor <NUM> at an eccentric position of a drive shaft <NUM>, and the drive shaft <NUM> extends out of the boss <NUM>. A circular hole <NUM> adapted to the boss <NUM> is provided on a housing <NUM>. The boss <NUM> rotates in the circular hole <NUM>, to adjust a position of the drive shaft <NUM> of the motor <NUM> on the housing <NUM>. In this case, a distance between a drive pulley <NUM> disposed on a drive shaft <NUM> of the motor <NUM> and a driven pulley <NUM> disposed on the housing <NUM> may be adjusted, to adjust tension of a transmission belt <NUM> used to connect the drive pulley <NUM> and the driven pulley <NUM>.

Solution <NUM> has at least the following two defects. Defect <NUM>: A relatively large adjustment distance or angle is required for adjusting the tension of the transmission belt <NUM>. Therefore, a volume of the housing <NUM> needs to be relatively large, and a relatively large housing <NUM> requires more materials and more arrangement space, which is inconvenient for entire vehicle arrangement. Defect <NUM>: The boss <NUM> is assembled into the circular hole <NUM>. To obtain sufficient stability, the boss <NUM> is relatively thick, and usually needs to reach <NUM> to <NUM>. Therefore, the housing <NUM> also needs to reach a same thickness correspondingly, so that assembly of the boss <NUM> into the circular hole <NUM> is more stable.

To adjust the tension of the transmission belt, solution <NUM> adds a tension pulley to change a path of the transmission belt, to adjust the tension of the transmission belt.

<FIG> is a schematic diagram of a structure of a transmission apparatus in solution <NUM>. As shown in <FIG>, a tension pulley <NUM> is further disposed between a drive pulley <NUM> and a driven pulley <NUM>, and an outer circumferential surface of a transmission belt <NUM> abuts against an outer circumferential surface of the tension pulley <NUM>, in other words, a specific force exists between the transmission belt <NUM> and the tension pulley <NUM>. A path of the transmission belt <NUM> is changed by using the tension pulley <NUM>. The tension pulley <NUM> is mounted in an eccentric manner, so that a position of the tension pulley <NUM> may be adjusted. A path length of the transmission belt <NUM> may be adjusted by changing the position of the tension pulley <NUM>. When the path of the transmission belt <NUM> is lengthened, the transmission belt <NUM> is tightened. When the path of the transmission belt <NUM> is shortened, the transmission belt <NUM> is loosened.

Solution <NUM>, which is not covered by the claims, has at least the following defects: The tension pulley <NUM> mounted in an eccentric manner is likely to be loosened after being used for a long time. This may cause a decrease in tension of the transmission belt <NUM> and cause noise when the transmission belt <NUM> operates. Therefore, the tension pulley <NUM> has a high loosening requirement during use.

This application provides a transmission apparatus, to adjust tension of a transmission belt. <FIG> is a schematic diagram of a structure of a transmission apparatus according to an embodiment of this application. As shown in <FIG>, the transmission apparatus in this application includes a drive pulley <NUM>, a driven pulley <NUM>, and a transmission belt <NUM>. The drive pulley <NUM> is connected to the driven pulley <NUM> by using the transmission belt <NUM>, and an axis L1 of the drive pulley is configured to be capable of rotating around a first axis L2. It should be noted that the first axis L2 provided in this embodiment of this specification of this application is a geometric description, and the first axis L2 may be a virtual rotation axis. The axis L1 of the drive pulley is controlled to rotate around the first axis L2 as a center, to adjust a distance between the drive pulley <NUM> and the driven pulley <NUM> and adjust a magnitude of tension of the transmission belt <NUM> between the drive pulley <NUM> and the driven pulley <NUM>. In this way, wear on the transmission belt <NUM> caused by excessively large tension can be avoided, or noise and slipping caused by excessively small tension can be avoided.

In the transmission apparatus provided in this embodiment of this application, a position of a rotation center of the drive pulley <NUM> may be changed. In a possible implementation, the rotation center of the drive pulley <NUM> may rotate around the first axis L2. After the rotation center of the drive pulley <NUM> rotates around the first axis L2, a relative distance between axis L1 of the drive pulley and an axis L3 of the driven pulley changes. Specifically, in the transmission apparatus provided in this embodiment of this application, the drive pulley <NUM> is connected to an output shaft of a motor, and the motor drives, by using the output shaft, the drive pulley <NUM> to rotate. When a position of the drive pulley <NUM> is adjusted, the motor may rotate around the first axis L2.

The transmission apparatus provided in this embodiment of this application further includes an adjustment pin. An axis of the adjustment pin coincides with the first axis L2, and the motor may be mounted on the housing by using the adjustment pin. When a position of the drive pulley <NUM> is adjusted, the motor may rotate around the axis of the adjustment pin.

A tension pulley <NUM> is further disposed on the adjustment pin, and an outer circumferential surface of the tension pulley <NUM> abuts against the transmission belt <NUM>. When the drive pulley <NUM> rotates around the adjustment pin for adjustment, a position between the tension pulley <NUM> and the drive pulley <NUM> may be changed. This can change a path through which the transmission belt <NUM> passes when connecting the drive pulley <NUM> and the driven pulley <NUM>, change a length of the transmission belt <NUM>, and adjust the tension of the transmission belt <NUM>.

In another possible implementation, the motor may be further connected to the housing by using a rotation axis, an axis of the rotation axis coincides with the first axis L2, and the motor may rotate around the rotation axis. In addition, the motor may be further connected to the housing in another manner, for example, may be connected through a shaft connection, a pin connection, or a rotation pair connection, so that the motor and the housing may rotate relative to each other. A person skilled in the art may understand that other implementations without creative input also fall within the scope of the technical solution of this application.

The transmission apparatus provided in this embodiment of this application may be applied to an REPS, or may be applied to a system that requires transmission, such as an electric tool. This is not limited herein. With reference to accompanying drawings, the following uses an REPS as an example to describe in detail a specific structure of the transmission apparatus in this embodiment of this application.

<FIG> is a schematic diagram of an application scenario of an REPS <NUM> according to an embodiment of this application. As shown in <FIG>, a steering system <NUM> is disposed in a vehicle <NUM>, and the steering system <NUM> may include front wheel steering 20a and rear wheel steering 20b. The REPS <NUM> in this embodiment of this application may be disposed in the front wheel steering 20a, to assist front wheel steering or may directly drive front wheel steering. Alternatively, the REPS <NUM> may be disposed in the rear wheel steering 20b, to drive rear wheel steering. This is not limited herein.

This embodiment of this application uses an example in which the vehicle <NUM> is an automobile, and this should not be considered as a limitation on this embodiment of this application. The vehicle <NUM> may be a conventional fuel automobile, or may be a new energy automobile such as a battery electric automobile or a hybrid automobile. The vehicle <NUM> may be any one of different types of automobiles such as a car, a truck, a passenger bus, and an SUV (sport utility vehicle, sport utility vehicle).

<FIG> is a schematic diagram of a transmission relationship of the front wheel steering 20a in <FIG>. As shown in <FIG> and <FIG>, the front wheel steering 20a includes: a steering wheel <NUM>, a first steering shaft <NUM>, a second steering shaft <NUM>, a third steering shaft <NUM>, a housing <NUM>, a steering rod <NUM>, and an REPS <NUM>. The housing <NUM> is fixedly disposed in the vehicle <NUM>, and the steering rod <NUM> is disposed in the housing <NUM>. Two ends of the steering rod <NUM> extend from two ends of the housing <NUM>, and the two ends of the steering rod <NUM> are respectively connected to two corresponding front wheels. Two ends of the second steering shaft <NUM> are respectively connected to one end of the first steering shaft <NUM> and one end of the third steering shaft <NUM> by using a universal joint, so that the first steering shaft <NUM>, the second steering shaft <NUM>, and the third steering shaft <NUM> can avoid some components in the vehicle <NUM>, facilitating mounting of the steering system <NUM>. The other end of the first steering shaft <NUM> is connected to a center of the steering wheel <NUM>, and a driver may control the steering wheel <NUM> to rotate. The other end of the third steering shaft <NUM> extends into the housing <NUM>, and a gear <NUM> is disposed at a corresponding position of the steering rod <NUM>. A rack <NUM> is disposed on the steering rod <NUM> in an extension direction of the steering rod <NUM> at a position corresponding to the gear <NUM>. The gear <NUM> is engaged with the rack <NUM>, and the driver rotates the steering wheel <NUM> to drive the gear <NUM> to rotate, to drive the steering rod <NUM> to move in an extension direction of the rack <NUM> to change a direction of a wheel.

The REPS <NUM> is fixedly disposed on the housing <NUM>. When the driver rotates the steering wheel <NUM> to drive the steering rod <NUM> to move in the extension direction of the rack <NUM>, the REPS <NUM> may output a specific force to the steering rod <NUM>, to reduce a force required by the driver to rotate the steering wheel <NUM>. Alternatively, the REPS <NUM> may further receive steering response requirement information sent by an autonomous driving center, and the REPS <NUM> drives the steering rod <NUM> to move in the extension direction of the rack <NUM>, to drive a front wheel of the vehicle <NUM> to change a direction.

<FIG> is a schematic diagram of a transmission relationship of the rear wheel steering 20b in <FIG>. As shown in <FIG> and <FIG>, the rear wheel steering 20b includes a housing <NUM>, a steering rod <NUM>, and an REPS <NUM>. The housing <NUM> is fixedly disposed in the vehicle <NUM>, and the steering rod <NUM> is disposed in the housing <NUM>. Two ends of the steering rod <NUM> extend from two ends of the housing <NUM>, and the two ends of the steering rod <NUM> are respectively connected to two corresponding rear wheels. The REPS <NUM> is fixedly disposed on the housing <NUM>. When the driver rotates the steering wheel <NUM> to control front wheel steering, the REPS <NUM> may drive the steering rod <NUM> to move in an extension direction of the steering rod <NUM>, to drive rear wheel steering. Alternatively, the REPS <NUM> may further receive steering response requirement information sent by the autonomous driving center, to drive a rear wheel of the vehicle <NUM> to change a direction.

<FIG> is a schematic diagram of a structure of the REPS <NUM> in <FIG>. <FIG> is a schematic exploded view of the structure of the REPS <NUM> in <FIG>. As shown in <FIG> and <FIG>, the REPS <NUM> includes a motor <NUM>, a drive pulley <NUM>, a driven pulley <NUM>, a bearing <NUM>, a transmission belt <NUM>, and an adjustment pin <NUM>. The motor <NUM> has a drive shaft <NUM>, and a drive pulley <NUM> is disposed on the drive shaft <NUM>. The motor <NUM> is hinged to the housing <NUM> by using the adjustment pin <NUM>. The adjustment pin <NUM> and the drive shaft <NUM> are disposed in parallel. The adjustment pin <NUM> is located on the motor <NUM> at an eccentric position of the drive shaft <NUM>, so that the motor <NUM> can rotate around the adjustment pin <NUM>, adjusting positions of the drive shaft <NUM> and the drive pulley <NUM>.

The driven pulley <NUM> is fixedly disposed on the housing <NUM> by using the bearing <NUM> or by using another rotation structure, so that the driven pulley <NUM> is located on the housing <NUM> at a position corresponding to the drive pulley <NUM> and can rotate on the housing <NUM>. The drive pulley <NUM> is connected to the driven pulley <NUM> by using the transmission belt <NUM>. The transmission belt <NUM> may be an annular part with specific elasticity that is made of rubber and additives, or made of another suitable material. There is a specific friction force between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>. When the drive pulley <NUM> rotates, the driven pulley <NUM> can be driven to rotate by using the transmission belt <NUM>, so that the drive pulley <NUM>, the driven pulley <NUM>, and the transmission belt <NUM> form a belt transmission structure.

The motor <NUM> rotates by using the adjustment pin <NUM> as a center, to adjust a position of the drive pulley <NUM> and further adjust a distance between the drive pulley <NUM> and the driven pulley <NUM>. This can adjust tension of the transmission belt <NUM>. Because the motor <NUM> is hinged to the housing <NUM> by using the adjustment pin <NUM>, a boss does not need to be disposed on a shell of the motor <NUM> as in solution <NUM>. This can reduce a material of the shell of the motor <NUM>, and a mold of the shell of the motor <NUM> does not need to be redesigned, provided that a hole is drilled at a corresponding position of the shell of the motor <NUM> to mount the adjustment pin <NUM>. This reduces a requirement for machining precision of the shell of the motor <NUM>, and saves production costs.

The housing <NUM> is enclosed to form a second chamber <NUM>, and the drive pulley <NUM>, the driven pulley <NUM>, the bearing <NUM>, and the transmission belt <NUM> are disposed in the second chamber <NUM>. The motor <NUM> is mounted on the housing <NUM>, and is located outside the second chamber <NUM>. The drive shaft <NUM> of the motor <NUM> extends into the second chamber <NUM>, and the drive pulley <NUM> is fixedly disposed on the drive shaft <NUM>, so that the motor <NUM> can drive the drive pulley <NUM> to rotate.

The driven pulley <NUM> may be disposed on the housing <NUM> by using the bearing <NUM> or by using the another rotation structure, so that the driven pulley <NUM> may rotate on the housing <NUM>. A manner of connecting the bearing <NUM> to both the driven pulley <NUM> and the housing <NUM> may be specifically that an outer ring of the bearing <NUM> is fixedly connected to the housing <NUM>, and an inner ring of the bearing <NUM> is fixedly connected to the driven pulley <NUM>. In this case, the driven pulley <NUM> may be fastened the housing <NUM> and can rotate on the housing <NUM>.

The steering rod <NUM> of the steering system <NUM> passes through the driven pulley <NUM>, and an axle of the steering rod <NUM> coincides with an axle of the driven pulley <NUM>. The steering rod <NUM> and the driven pulley <NUM> are connected by using a thread to form a screw transmission structure, so that when the driven pulley <NUM> rotates, the steering rod <NUM> may be driven to move linearly in an axial direction. The screw transmission structure may be a trapezoidal screw structure, a ball screw structure, a planetary roller screw structure, or any other possible implementation form. The trapezoidal screw structure means that the steering rod <NUM> and the driven pulley <NUM> are connected through a threaded connection based on a trapezoidal thread, to convert a rotating motion of the driven pulley <NUM> into a linear motion of the steering rod <NUM>. This structure has an advantage such as a simple structure and low costs. In the ball screw structure, a ball is placed between the steering rod <NUM> and the driven pulley <NUM> that are connected through the threaded connection, and sliding friction is replaced by rolling friction. This can reduce a friction force between the steering rod <NUM> and the driven pulley <NUM>, and improve transmission efficiency between the steering rod <NUM> and the driven pulley <NUM>. In the planetary roller screw structure, a plurality of rollers are disposed in the driven pulley <NUM>. The rollers may rotate in the driven pulley <NUM>. The plurality of rollers surround an outer circumferential surface of the steering rod <NUM>. A thread on an outer circumferential surface of the roller is engaged with a thread on an outer circumferential surface of the steering rod <NUM>. Therefore, point contact between the ball and both the steering rod <NUM> and the driven pulley <NUM> in the ball screw structure may be converted into line contact between the roller and the steering rod <NUM>. This can increase a contact surface while maintaining high-efficiency transmission, improve a bearing capacity and rigidity between the steering rod <NUM> and the driven pulley <NUM>, and enhance an impact resistance capability between the steering rod <NUM> and the driven pulley <NUM>.

As above, when the driver operates the steering wheel <NUM> to control the vehicle <NUM> to turn, a torque angle sensor disposed in the vehicle <NUM> can collect steering information transferred by the steering wheel <NUM>, and transfer the steering information to a controller in the vehicle <NUM>. After receiving the steering information, the controller performs calculation and processing, and then sends a motor current control requirement to the motor <NUM>, to control the drive shaft <NUM> of the motor <NUM> to output a corresponding torque and rotational speed/angle. The steering rod <NUM> is finally driven to perform linear motion through the belt transmission structure formed by the drive pulley <NUM>, the driven pulley <NUM>, and the transmission belt <NUM>, and the screw transmission structure between the steering rod <NUM> and the driven pulley <NUM>. Therefore, the REPS <NUM> in the front wheel steering 20a may output a specific force to the steering rod <NUM> when the driver operates the steering wheel <NUM>, to assist front wheel steering of the vehicle <NUM>, and reduce a force required by the driver to operate the steering wheel <NUM>. In addition, the REPS <NUM> in the rear wheel steering 20b may control the steering rod <NUM> to perform linear motion, to drive rear wheel steering of the vehicle <NUM>. This improves mobility and stability of the vehicle <NUM> during steering, and reduces a turning radius of the vehicle <NUM>.

Alternatively, the REPS <NUM> in the front wheel steering 20a and the REPS <NUM> in the rear wheel steering 20b may directly receive the steering response requirement information sent by the autonomous driving center, to drive the front wheel and the rear wheel of the vehicle <NUM> to change directions, implementing automatic control of steering of the vehicle <NUM>.

<FIG> is a schematic diagram of a structure of the adjustment pin <NUM> according to an embodiment of this application, and shows a specific structure of the adjustment pin <NUM> in <FIG>. As shown in <FIG>, the adjustment pin <NUM> may be in a cylindrical shape, and the adjustment pin <NUM> may be divided into two parts in an axial direction: a fixed end <NUM> and an adjustment end <NUM>. The fixed end <NUM> is configured to be fixedly connected to the housing <NUM>, and a connection manner may be, for example, a threaded connection or a press-fit connection. Because the fixed connection between the adjustment pin <NUM> and the housing <NUM> imposes a relatively low requirement on a thickness of the housing <NUM>, the thickness of the housing <NUM> may be set to, for example, <NUM> to <NUM>. The thickness of the housing <NUM> does not need to be set to <NUM> to <NUM>, to obtain sufficient stability in the foregoing solution <NUM>. This can reduce the thickness of the housing <NUM>, reduce a weight of the housing <NUM>, and reduce production costs. In addition, after the motor <NUM> is mounted on the housing <NUM>, the drive shaft <NUM> needs to pass through the housing <NUM> before the drive pulley <NUM> is mounted. Reducing the thickness of the housing <NUM> may correspondingly reduce a length of the drive shaft <NUM>, so that a length of the drive shaft <NUM> exposed from the motor <NUM> is shorter. Therefore, rigidity and durability of the drive shaft <NUM> are improved, and transmission of the drive shaft <NUM> is more stable.

As shown in <FIG> and <FIG>, a length of the fixed end <NUM> is greater than the thickness of the housing <NUM>. After the fixed end <NUM> is fixedly connected to the housing <NUM>, a part of the fixed end <NUM> is exposed from the housing <NUM>, and is configured to be hinged to the motor <NUM>. In this case, the motor <NUM> can rotate on the housing <NUM> to adjust positions of the drive shaft <NUM> and the drive pulley <NUM>, and the motor <NUM> can also be positioned to facilitate bolt fastening. In addition, the adjustment pin <NUM> is connected to the motor <NUM> and the housing <NUM>, so that connection strength between the housing <NUM> and the motor <NUM> can be improved. After the motor <NUM> and the housing <NUM> are fastened by using a bolt, when the bolt is loose or fails due to vibration or another reason, for example, when only one bolt in a plurality of bolts is fastened between the motor <NUM> and the housing <NUM>, and other bolts all fail due to fracture or detachment, the adjustment pin <NUM> may prevent the motor <NUM> from rotating around the only one bolt, fastening the motor <NUM>. After the adjustment pin <NUM> is fastened to the housing <NUM>, the adjustment end <NUM> is located in the second chamber <NUM>. A tension pulley <NUM> is fixedly disposed on the adjustment end <NUM> at a corresponding position of the drive pulley <NUM> and the driven pulley <NUM>. The tension pulley <NUM> may be formed by the bearing <NUM> or another type of rotating component, and the tension pulley <NUM> may be fastened to the adjustment end <NUM> through an interference fit, a thread connection, or the like.

Radiuses of the fixed end <NUM> and the adjustment end <NUM> may be set to be different. For example, as shown in <FIG>, a radius of the fixed end <NUM> is less than that of the adjustment end <NUM>. A positioning end face <NUM> is disposed between the fixed end <NUM> and the adjustment end <NUM>, and the positioning end face <NUM> is connected to outer circumferential surfaces of both the fixed end <NUM> and the adjustment end <NUM>. The positioning end face <NUM> may be set to be at a specific tilt angle with the outer circumferential surfaces of both the fixed end <NUM> and the adjustment end <NUM>, or may be set to be perpendicular to the outer circumferential surfaces of both the fixed end <NUM> and the adjustment end <NUM> as shown in <FIG>. When the adjustment pin <NUM> is fastened to and mounted on the housing <NUM>, the positioning end face <NUM> may abut against the housing <NUM>, to perform positioning.

<FIG> is another schematic diagram of a structure of an adjustment pin <NUM> according to an embodiment of this application. As shown in <FIG>, radiuses of the fixed end <NUM> and the adjustment end <NUM> may be set to be the same. An annular flange or another protrusion structure is disposed at a connection position between the fixed end <NUM> and the adjustment end <NUM>. A positioning end face <NUM> is disposed on a surface that is of the annular flange and that faces the fixed end <NUM>. When the adjustment pin <NUM> is fastened to and mounted on the housing <NUM>, the positioning end face <NUM> may abut against the housing <NUM>, to perform positioning.

As shown in <FIG>, the shell <NUM> of the motor <NUM> is enclosed to form a first chamber <NUM> in the motor <NUM>. A stator fixedly connected to the shell <NUM> and a rotor fixedly connected to the drive shaft <NUM> may be disposed in the first chamber <NUM>. The first chamber <NUM> may be isolated from an outside of the motor <NUM> by the shell <NUM> of the motor <NUM>. After the motor <NUM> is hinged to the adjustment pin <NUM>, the fixed end <NUM> extends into the first chamber <NUM>. As shown in <FIG> and <FIG>, a through hole <NUM> is further provided in the adjustment pin <NUM>. The through hole <NUM> may be provided along an axle of the adjustment pin <NUM> as shown in <FIG> and <FIG>, or may be located at another position in the adjustment pin <NUM>. When the through hole <NUM> is located at the axle, the through hole <NUM> may be processed more conveniently during production of the adjustment pin <NUM>, improving production efficiency. Alternatively, the adjustment pin <NUM> may be directly processed by using a pipe material, so that a drilling operation is not required during production. This simplifies a production procedure and improves production efficiency.

A first end 2765a of the through hole <NUM> is located in the first chamber <NUM>, and a second end 2765b of the through hole <NUM> is located outside the motor <NUM>, so that the first chamber <NUM> is connected to the outside of the motor <NUM>. When the rotor of the motor <NUM> rotates, air in the first chamber <NUM> is driven to move in the first chamber <NUM>, so that a pressure in the first chamber <NUM> fluctuates, and the motor <NUM> generates relatively large noise. The first chamber <NUM> is connected to the outside of the motor <NUM> through the through hole <NUM>, so that air can enter or exit the first chamber <NUM> through the through hole <NUM>. This can reduce air pressure fluctuation in the first chamber <NUM> when the rotor of the motor <NUM> rotates, and reduce noise generated when the motor <NUM> rotates. In addition, air may enter or exit the first chamber <NUM> through the through hole <NUM>, so that air may flow between the first chamber <NUM> and the outside of the motor <NUM>. In this case, air heated in the first chamber <NUM> due to operation of the motor <NUM> is exchanged with air outside the motor <NUM>. This implements heat exchange, and improves heat dissipation efficiency of the motor <NUM>.

As shown in <FIG>, the second end 2765b of the through hole <NUM> may be located in the second chamber <NUM>, so that the first chamber <NUM> can be connected to the second chamber <NUM> through the through hole <NUM>. In this case, air tightness detection can be simultaneously performed on both the first chamber <NUM> and the second chamber <NUM>, to detect air tightness of both the motor <NUM> and the housing <NUM>.

Further, the adjustment pin <NUM> may be a straight shaft in which axis of each shaft segment lies on a same straight line, or may be a crankshaft in which axis of each shaft segment lies on different straight lines. This is not limited.

<FIG> is a schematic axial diagram of a motor <NUM> according to an embodiment of this application, and shows a possible manner in which the motor <NUM> is fixedly connected to a housing <NUM>. As shown in <FIG>, an annular first fastening part <NUM> is disposed on a side that is of a shell <NUM> of the motor <NUM> and that faces the housing <NUM> along an outer circumferential surface of the shell <NUM>. A plurality of connection holes <NUM> are provided in the first fastening part <NUM>. A bolt may pass through the connection hole <NUM> to connect to the housing <NUM> through a threaded connection, so that the motor <NUM> is fastened to the housing <NUM>. The connection hole <NUM> may be an arc hole shown in <FIG>, or may be an oblong hole. The connection hole <NUM> may be arranged in a manner in which the adjustment pin <NUM> is used as a circle center, as shown in <FIG>. In this case, after the motor <NUM> rotates a specific angle by using the adjustment pin <NUM> as a center, the bolt can pass through the connection hole <NUM> to fixedly connect the motor <NUM> to the housing <NUM>.

<FIG> is another schematic axial diagram of a motor <NUM> according to an embodiment of this application, and shows another possible manner in which the motor <NUM> is fixedly connected to a housing <NUM>. As shown in <FIG>, a plurality of positioning racks <NUM> are disposed on a first fastening part <NUM> of the motor <NUM>, and the positioning racks <NUM> are arranged by using an adjustment pin <NUM> as a circle center. A fastening plate <NUM> configured to fasten the motor <NUM> on the housing <NUM> is further included. The fastening plate <NUM> is fastened, by using a bolt, to the housing <NUM> at a position corresponding to the positioning rack <NUM>. The fastening plate <NUM> extends to the first fastening part <NUM>, and may press the first fastening part <NUM> against the housing <NUM> for fastening. A positioning pinion <NUM> is disposed on the fastening plate <NUM> at a position corresponding to the rack <NUM>. The positioning pinion <NUM> is engaged with the positioning rack <NUM>, to prevent the motor <NUM> from rotating.

<FIG> another schematic diagram of a structure of an REPS <NUM> according to an embodiment of this application, and shows another structural form of the REPS <NUM> in <FIG>. As shown in <FIG>, a second chamber <NUM> is disposed in a housing <NUM>, and an adjustment pin <NUM> and two motors <NUM> are fixedly disposed on the housing <NUM>. A tension pulley <NUM> is disposed in a middle part of the adjustment pin <NUM>, and the tension pulley <NUM> is located in the second chamber <NUM>. Two ends of the adjustment pin <NUM> extend out of an outer surface of the housing <NUM>, and are respectively hinged to the two motors <NUM>. The two motors <NUM> are oppositely disposed on the housing <NUM>, and axles of drive shafts <NUM> of the two motors <NUM> coincide with each other, and the drive shafts extend into the second chamber <NUM> for a fixed connection. A drive pulley <NUM> is disposed on the drive shaft <NUM>. A driven pulley <NUM> is disposed in the second chamber <NUM>. The drive pulley <NUM> is connected to the driven pulley <NUM> by using a transmission belt <NUM>. The tension pulley <NUM> is located between the drive pulley <NUM> and the driven pulley <NUM>, and an outer circumferential surface of the tension pulley <NUM> abuts against the transmission belt <NUM>. In this case, the two motors <NUM> may simultaneously rotate by using the adjustment pin <NUM> as an axle, to adjust positions of the drive shaft <NUM> and the drive pulley <NUM>. In this case, a distance between the drive pulley <NUM> and the driven pulley <NUM> may be adjusted, to adjust tension of the transmission belt <NUM>. In addition, the two motors <NUM> may be mutually redundant. When one motor <NUM> is faulty and one drive shaft <NUM> cannot rotate, the other motor <NUM> may continue to work, to drive the other drive shaft <NUM> to rotate. In this way, the REPS <NUM> can still work normally when one motor <NUM> is faulty. This improves reliability of the REPS <NUM>.

Further, the motor <NUM> may be a six-phase motor, a twelve-phase motor, or another type of multi-phase induction motor, so that multiple phases in the motor <NUM> are redundant to each other. When one (or several) stator winding is open-circuited or one (or several) bridge arm of an inverter is open-circuited, starting and running of the motor <NUM> are not affected. This can further improve reliability of the REPS <NUM>.

<FIG> is another schematic diagram of a structure of the adjustment pin <NUM> according to an embodiment of this application, and shows a structure of the adjustment pin <NUM> in <FIG>. As shown in <FIG>, the adjustment pin <NUM> may be in a cylindrical shape, and the adjustment pin <NUM> may be divided, in an axial direction, into two fixed ends <NUM> at two ends and one adjustment end <NUM> at a middle position. The adjustment end <NUM> is located in the second chamber <NUM>, and the tension pulley <NUM> is disposed on the fixed end <NUM>. The two fixed ends <NUM> located at the two ends are fixedly connected to the housing <NUM> respectively, and the two fixed ends <NUM> extend out from the housing <NUM> and enter the first chamber <NUM> of the motor <NUM>. A radius of the adjustment end <NUM> is greater than radiuses of the two fixed ends <NUM>, and a positioning end face <NUM> is formed at a connection position between the adjustment end <NUM> and the two fixed ends <NUM>. After the adjustment pin <NUM> is mounted, the positioning end face <NUM> abuts against an inner surface of the second chamber <NUM>. The positioning end face <NUM> is disposed, so that positioning and mounting can be implemented when the adjustment pin <NUM> is mounted and fastened. In addition, the positioning end face <NUM> abuts against the inner surface of the second chamber <NUM>, so that mounting stability of the adjustment pin <NUM> is improved. Through holes <NUM> are further provided in the adjustment pin <NUM>. One part of through holes <NUM> are provided in an axial direction of the adjustment pin <NUM>, and the other part of through holes <NUM> are provided in a radial direction of the adjustment end <NUM>. The two parts of the through hole <NUM> are connected. The part of through holes <NUM> provided in the axial direction of the adjustment pin <NUM> form an open first end 2765a at each of the two ends of the adjustment pin <NUM>, the other part of through holes <NUM> provided in the radial direction of the adjustment end <NUM> form an open second end 2765b on a surface of the adjustment end <NUM>. After mounting, two first ends 2765a are respectively located in the first chambers <NUM> of the two motors <NUM>, and the second end 2765b is located in the second chamber <NUM>, so that the second chamber <NUM> is connected to the two first chambers <NUM> through the through hole <NUM>.

<FIG> is a schematic diagram of a position relationship among a tension pulley <NUM>, a drive pulley <NUM>, and a driven pulley <NUM>. As shown in <FIG>, an outer circumferential surface of the tension pulley <NUM> abuts against a transmission belt <NUM>, and a path of the transmission belt <NUM> between the drive pulley <NUM> and the driven pulley <NUM> is changed by using the tension pulley <NUM>. In this case, the transmission belt <NUM> on one side is not directly connected to the driven pulley <NUM> by the drive pulley <NUM>, but is connected to the driven pulley <NUM> after the path is changed by the tension pulley <NUM>. In this case, a path through which the transmission belt <NUM> passes between the drive pulley <NUM> and the driven pulley <NUM> is longer. This increases tension of the transmission belt <NUM>, and expands an adjustment range of the tension of the transmission belt <NUM>.

Further, as shown in <FIG>, the outer circumferential surface of the tension pulley <NUM> may be disposed to abut against an outer circumferential surface of the transmission belt <NUM>, or may be disposed to abut against an inner circumferential surface of the transmission belt <NUM>. The path of the transmission belt <NUM> between the drive pulley <NUM> and the driven pulley <NUM> is changed by using the tension pulley <NUM>, so that a belt contact angle formed by the transmission belt <NUM>, the drive pulley <NUM>, and the driven pulley <NUM> (which is a central angle corresponding to a contact arc between the transmission belt <NUM> and the pulleys) may be changed. A larger belt contact angle indicates a larger contact area between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>, and a maximum static friction force between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM> is also greater. As shown in <FIG>, when there is no tension pulley <NUM>, a belt contact angle formed by the transmission belt <NUM> and the drive pulley <NUM> is α1, and a belt contact angle formed by the transmission belt <NUM> and the driven pulley <NUM> is α2. When the outer circumferential surface of the tension pulley <NUM> abuts against the outer circumferential surface of the transmission belt <NUM>, a belt contact angle formed by the transmission belt <NUM> and the drive pulley <NUM> is α1', and a belt contact angle formed by the transmission belt <NUM> and the driven pulley <NUM> is α2'. When the outer circumferential surface of the tension pulley <NUM> abuts against the inner circumferential surface of the transmission belt <NUM>, a belt contact angle formed by the transmission belt <NUM> and the drive pulley <NUM> is α1", and a belt contact angle formed by the transmission belt <NUM> and the driven pulley <NUM> is α2". As shown in <FIG>, α1' > α1 > α1", and α2' > α2 > α2". Therefore, when the outer circumferential surface of the tension pulley <NUM> abuts against the outer circumferential surface of the transmission belt <NUM>, the belt contact angle formed by the transmission belt <NUM>, the drive pulley <NUM>, and the driven pulley <NUM> may be increased, to increase the maximum static friction force between the transmission belt <NUM>, and both the drive pulley <NUM>, and the driven pulley <NUM>. This can improve anti-slip performance between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>, and reduce wear of the transmission belt <NUM>, so that the belt transmission is more stable.

<FIG> is a schematic diagram of a relationship between a length of a transmission belt <NUM> and a position of a drive pulley <NUM>. As shown in <FIG>, a center of the tension pulley <NUM> (namely, a center of an adjustment pin <NUM>) is O, a center of the drive pulley <NUM> is O<NUM>, and a radius is r<NUM>. A center of a driven pulley <NUM> is O<NUM>, and a radius is r<NUM>. It is assumed that O<NUM>O<NUM> = a, OO<NUM> = b, OO<NUM> = c, and ∠O<NUM>OO<NUM> = β. According to the trigonometric function principle, the following can be obtained: <MAT> <MAT>.

Therefore, b and c are fixed values, and a value of a is related to an angle value of β.

It is assumed that the length of the transmission belt <NUM> that is between the drive pulley <NUM> and the driven pulley <NUM> and that is opposite to the tension pulley <NUM> is <NUM>, and an angle between the transmission belt <NUM> and O<NUM>O<NUM> is δ. Therefore, according to the trigonometric function principle, it can be obtained that: <MAT> <MAT> <MAT> <MAT>.

<FIG> is a schematic diagram of adjusting tension of a transmission belt <NUM>. As shown in <FIG>, when the tension of the transmission belt <NUM> is adjusted, positions of a driven pulley <NUM> and a tension pulley <NUM> are fixed, and a motor <NUM> rotates by using an adjustment pin <NUM> as a center. In this case, a drive pulley <NUM> rotates by using a center O of the tension pulley <NUM> as a center. A position of the drive pulley <NUM> is adjusted counterclockwise, so that a rotation angle of the drive pulley <NUM> is θ'. In this case, a center of the drive pulley <NUM> is O<NUM>', and a length of the transmission belt <NUM> that is between the drive pulley <NUM> and the driven pulley <NUM> and that is opposite to the tension pulley <NUM> is <NUM>'. The position of the drive pulley <NUM> is adjusted clockwise, so that the rotation angle of the drive pulley <NUM> is θ''. In this case, the center of the drive pulley <NUM> is O<NUM>", and the length of the transmission belt <NUM> that is between the drive pulley <NUM> and the driven pulley <NUM> and that is opposite to the tension pulley <NUM> is <NUM>". It is assumed that O<NUM>' O<NUM> = a', and O<NUM>' O<NUM> = a". According to the trigonometric function principle, the following can be obtained: <MAT> <MAT> <MAT> <MAT> <MAT> <MAT> <MAT> <MAT>.

A length of the transmission belt <NUM> includes a sum of lengths of contact parts between the transmission belt <NUM>, and the drive pulley <NUM>, the driven pulley <NUM>, and the tension pulley <NUM>, and lengths of parts in which the transmission belt <NUM> is tangent to the drive pulley <NUM>, the driven pulley <NUM>, and the tension pulley <NUM>. When the tension of the transmission belt <NUM> is adjusted, an adjustment angle of the drive pulley <NUM> is very small. Therefore, a magnitude of the adjustment angle (θ' or θ") may be considered as equal to an adjusted radian (a radian change of the contact parts between the transmission belt <NUM>, and the drive pulley <NUM>, the driven pulley <NUM>, and the tension pulley <NUM>). In addition, because the adjustment angle is very small, a length change of the parts in which the transmission belt <NUM> is tangent to the drive pulley <NUM> and the driven pulley <NUM> on a side opposite to the tension pulley <NUM> may be considered as equal to
a length change of parts in which the transmission belt <NUM> is tangent to the drive pulley <NUM> and the driven pulley <NUM> on a side corresponding to the tension pulley <NUM>.

It is assumed that when the drive pulley <NUM> rotates counterclockwise, a shortened length of the transmission belt <NUM> is Δl<NUM>; when the drive pulley <NUM> rotates clockwise, an elongated length of the transmission belt <NUM> is Δl<NUM>. In conclusion, <MAT> <MAT>.

In this case, the length of the transmission belt <NUM> may be adjusted by adjusting a position of the drive pulley <NUM>. A larger length of the transmission belt <NUM> indicates greater tension of the transmission belt <NUM>. The position of the drive pulley <NUM> is adjusted, to adjust the tension of the transmission belt <NUM>, so that wear on the transmission belt <NUM> cannot be caused due to excessively large tension of the transmission belt <NUM>, or noise and slipping cannot be caused due to excessively small tension.

Further, as shown in <FIG>, when the motor <NUM> rotates by using the adjustment pin <NUM> as the center, the drive pulley <NUM> correspondingly rotates by using the tension pulley <NUM> as the center. This can adjust the position of the drive pulley <NUM>, adjust a length of O<NUM>O<NUM> (that is, a distance between the drive pulley <NUM> and the driven pulley <NUM>), and further adjust a distance between the center O of the tension pulley <NUM> and O<NUM>O<NUM>. A larger length of O<NUM>O<NUM> indicates a larger length of the transmission belt <NUM>; a smaller distance between O and the O<NUM>O<NUM> indicates a larger length of the transmission belt <NUM>. When an outer circumferential surface of the tension pulley <NUM> abuts against an outer circumferential surface of the transmission belt <NUM>, the drive pulley <NUM> rotates clockwise/counterclockwise by using the tension pulley <NUM> as the center, so that a length of O<NUM>O<NUM> may be increased/decreased, and a distance between O and O<NUM>O<NUM> may also be decreased/increased. In other words, the distance between O<NUM>O<NUM> and the distance between O and O<NUM>O<NUM> may be simultaneously adjusted, to increase an adjustment range of the tension of the transmission belt <NUM>. Alternatively, the tension of the transmission belt <NUM> may be adjusted by adjusting a relatively small angle of the drive pulley <NUM>, so that space required for adjusting the drive pulley <NUM> may be reduced, and a volume of the housing <NUM> may be reduced.

An embodiment of this application further provides a transmission apparatus adjustment method, to adjust tension of a transmission belt <NUM> in a transmission apparatus.

<FIG> is a schematic flowchart of a transmission apparatus adjustment method <NUM> according to an embodiment of this application. An REPS <NUM> is used as an example to describe a specific procedure of adjusting tension of a transmission belt <NUM>. As shown in <FIG>, a specific procedure of the transmission apparatus adjustment method <NUM> in this application includes the following steps.

Step S110: Disconnect a fixed connection between a motor <NUM> and a housing <NUM>.

Step S120: Drive the motor <NUM> to rotate on an adjustment pin <NUM>.

The adjustment pin <NUM> is mounted on the housing <NUM>. The adjustment pin <NUM> is staggered with a drive shaft <NUM> of the motor <NUM>. A drive pulley <NUM> on the drive shaft <NUM> is connected to a driven pulley <NUM> on the housing <NUM> by using a transmission belt <NUM>. In this case, the motor <NUM> rotates on the adjustment pin <NUM>, so that the drive shaft <NUM> and the drive pulley <NUM> on the drive shaft <NUM> rotate by using the adjustment pin <NUM> as a center. This can adjust a distance between the drive pulley <NUM> and the driven pulley <NUM>, and further adjust tension of the transmission belt <NUM>.

Step S130: Abut an outer circumferential surface of the tension pulley <NUM> against the transmission belt <NUM>.

The tension pulley <NUM> is disposed on the adjustment pin <NUM>, so that the outer circumferential surface of the tension pulley <NUM> abuts against the transmission belt <NUM>. This can change and extend a path through which the transmission belt <NUM> passes when connecting the drive pulley <NUM> and the driven pulley <NUM>, change a length of the transmission belt <NUM>, and adjust the tension of the transmission belt <NUM>.

Further, step S130 may further include step S131 or step S132.

Step S131: Abut the outer circumferential surface of the tension pulley <NUM> against an inner circumferential surface of the transmission belt <NUM>.

This can change and extend the path through which the transmission belt <NUM> passes when connecting the drive pulley <NUM> and the driven pulley <NUM>, change the length of the transmission belt <NUM>, and adjust the tension of the transmission belt <NUM>.

Step S132: Abut the outer circumferential surface of the tension pulley <NUM> against an outer circumferential surface of the transmission belt <NUM>.

In this case, the path in which the transmission belt <NUM> passes when connecting the drive pulley <NUM> and the driven pulley <NUM> may be changed by using the tension pulley <NUM>, so that a distance between the transmission belt <NUM> located on two sides of a part between the drive pulley <NUM> and the driven pulley <NUM> is shorter, and both a contact radian and a corresponding belt contact angle between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM> are larger. This increases a contact area between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>, improves a maximum static friction force between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>, reduces a possibility of slipping between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>, and reduces wear of the transmission belt <NUM>. In addition, the motor <NUM> rotates relative to the housing <NUM>, and the drive pulley <NUM> is adjusted away from/towards the driven pulley <NUM>. In this case, when the transmission belt <NUM> is extended/shortened, the tension pulley <NUM> correspondingly moves towards/far away from a connection line between a center of the drive pulley <NUM> and a center of the driven pulley <NUM>, so that the tension pulley <NUM> can tighten/loosen the transmission belt <NUM>. This can increase an adjustment range of the tension of the transmission belt <NUM>, reduce an angle at which the motor <NUM> needs to rotate when the tension of the transmission belt <NUM> is adjusted, and reduce space required for adjusting positions of the motor <NUM> and the drive pulley <NUM>.

Step S140: Detect the tension of the transmission belt <NUM>.

The tension of the transmission belt <NUM> is detected by using a detection device, to determine whether the tension of the transmission belt <NUM> is within a predetermined range.

Step S150: Determine whether the tension of the transmission belt is between a first tension threshold and a second tension threshold.

When the tension of the transmission belt <NUM> is less than the first tension threshold, the tension of the transmission belt <NUM> is excessively small, and slipping is likely to occur between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>. This affects transmission efficiency and control precision, and causes relatively large noise when the transmission belt <NUM> operates. In this case, step S120 needs to be performed again, to re-adjust a position of the motor <NUM>, so that the tension of the transmission belt <NUM> increases.

When the tension of the transmission belt <NUM> is greater than the second tension threshold, the tension of the transmission belt <NUM> is excessively large, and a friction force between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM> is excessively large. This worsens wear of the transmission belt <NUM> and affects a service life of the transmission belt <NUM>. In this case, step S120 needs to be performed again, to re-adjust a position of the motor <NUM>, so that the tension of the transmission belt <NUM> decreases.

When the tension of the transmission belt <NUM> is greater than or equal to the first tension threshold, and less than or equal to the second tension threshold, the tension of the transmission belt <NUM> is within an appropriate range, so that a sufficient friction force can be generated between the transmission belt <NUM> and both the drive pulley <NUM> and the driven pulley <NUM>. In this way, slipping or noise can be avoided, and wear on the transmission belt <NUM> caused by excessively large tension can be further avoided. In this case, the motor <NUM> may be fixedly connected to the housing <NUM>.

Step S160: Fixedly connect the motor <NUM> and the housing <NUM>.

The motor <NUM> may be fixedly connected to the housing <NUM> through bolt fastening, pressing fastening, clamping fastening, or the like, so that the transmission belt <NUM> can maintain adjusted tension for transmission.

An embodiment of this application further provides an air tightness detection method, to detect air tightness of both a second chamber <NUM> of a housing <NUM> and a first chamber <NUM> of a motor <NUM>. The motor <NUM> is connected to the housing <NUM> by using an adjustment pin <NUM>. A through hole <NUM> that connects the second chamber <NUM> and the first chamber <NUM> is provided in the adjustment pin <NUM>.

<FIG> is a schematic flowchart of an air tightness detection method <NUM> according to an embodiment of this application. As shown in <FIG>, a specific procedure of the air tightness detection method <NUM> in this application includes the following steps.

Step S201: Input gas into the second chamber <NUM>.

An air tightness detector may be connected to a housing <NUM> through a connection hole specially provided in the housing <NUM>, or may be connected by using the steering rod <NUM> extending out of the housing <NUM>. After the connection, the air tightness detector inputs gas into the second chamber <NUM>, to increase an air pressure in the second chamber <NUM>.

Step S202: Detect the air pressure in the second chamber <NUM>.

The detecting the air pressure in the second chamber <NUM> may be detecting the air pressure in the second chamber <NUM> by using a barometer provided by the air tightness detector or another device, to determine whether the air pressure in the second chamber <NUM> reaches a first air pressure threshold. The first air pressure threshold may be an air pressure value corresponding to an air tightness level.

Step S203: Determine whether the air pressure in the second chamber <NUM> reaches the first air pressure threshold.

When it is detected that the air pressure in the second chamber <NUM> does not reach the first air pressure threshold, the air tightness detector is controlled to continue to input gas into the second chamber <NUM>. When it is detected that the air pressure in the second chamber <NUM> reaches the first upper threshold, the air tightness detector is controlled to stop inputting gas into the second chamber <NUM>.

The air tightness detector is controlled to keep both the second chamber <NUM> and the first chamber <NUM> in a current status for the first duration. The first duration may be <NUM> minutes, <NUM> minutes, or another duration. If air tightness of both the second chamber <NUM> and the first chamber <NUM> is qualified, gas in both the second chamber <NUM> and the first chamber <NUM> does not leak or only a small amount of gas leaks. If air tightness of the second chamber <NUM> and the first chamber <NUM> is not qualified, gas that exceeds a preset amount in both the second chamber <NUM> and the first chamber <NUM> leaks.

Step S205: Detect the air pressure in the second chamber <NUM>.

The air pressure in the second chamber <NUM> is detected by using the barometer provided by the air tightness detector or the another device, to determine whether the air pressure in the second chamber <NUM> is greater than or equal to a second air pressure threshold.

Step S206: Determine whether the air pressure in the second chamber <NUM> is greater than or equal to the second air pressure threshold.

When it is detected that the air pressure in the second chamber <NUM> is greater than or equal to the second air pressure threshold, it indicates that gas in both the second chamber <NUM> and the first chamber <NUM> does not leak or only a small amount of gas leaks, and the air tightness of both the second chamber <NUM> and the first chamber <NUM> is qualified. When it is detected that the air pressure in the second chamber <NUM> is less than the second air pressure threshold, it indicates that gas that exceeds the preset amount in both the second chamber <NUM> and the first chamber <NUM> leaks, and air tightness of the second chamber <NUM> or air tightness of the first chamber <NUM> is not qualified.

Step S207: When it is detected that the air pressure in the second chamber <NUM> is greater than or equal to the second air pressure threshold, the air tightness of both the second chamber <NUM> and the first chamber <NUM> is qualified.

Step S208: When it is detected that the air pressure in the second chamber <NUM> is less than the second air pressure threshold, the air tightness of the second chamber <NUM> or the air tightness of the first chamber <NUM> is not qualified.

Claim 1:
A transmission apparatus, comprising: a drive pulley (<NUM>), a driven pulley (<NUM>), and a transmission belt (<NUM>), wherein the drive pulley (<NUM>) is connected to the driven pulley (<NUM>) by using the transmission belt (<NUM>), and an axis (L1) of the drive pulley (<NUM>) is rotatable around a first axis (L2);
an adjustment pin (<NUM>), wherein an axis (L2) of the adjustment pin (<NUM>) coincides with the first axis (L2); and characterized by
a tension pulley (<NUM>), wherein the tension pulley (<NUM>) is disposed on the adjustment pin (<NUM>), and an outer circumferential surface of the tension pulley abuts against the transmission belt (<NUM>).