A transmission, diverter and vehicle

Abstract

The application provides a transmission device, a steering device and a vehicle. The transmission device comprises a screw main shaft, a plurality of planetary rollers arranged in the circumferential direction of the screw main shaft and in meshing transmission with the screw main shaft, two spaced-apart and opposite retainer sleeves, which are sleeved on the screw main shaft, and which are adapted to be rotatably mounted on a housing. The planetary rollers directly or indirectly abut against the two retainer sleeves and can rotate around their own axes. A transmission wheel is connected to the retainer sleeves. The transmission wheel can rotate around the axis of the screw main shaft and drive the planetary rollers to rotate together through the retainer sleeves, so as to drive the axial movement of the screw main shaft. The axial force is transmitted between the screw main shaft, the planetary rollers, the retainer sleeves and the housing to drive the axial movement of the screw, so that the structure is simpler, the space occupation in the radial and axial directions is smaller, and the cost is lower.

Description

Technical Field

[0001] This application relates to the field of mechanical transmission, and in particular to a planetary roller screw transmission device, a steering gear, and a vehicle. Background Technology

[0002] Planetary roller screws are increasingly used in automotive rear wheel steering systems due to their advantages of high transmission efficiency and high precision. However, in related technologies, planetary roller screw transmission schemes have complex structures, occupy a large space, and have high costs. Summary of the Invention

[0003] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a transmission device with a simple structure, small space occupation, and low cost.

[0004] This application further proposes a steering system and a vehicle.

[0005] In a first aspect, a transmission device is proposed, comprising: a lead screw spindle; a plurality of planetary rollers arranged circumferentially along the lead screw spindle and meshing with the lead screw spindle for transmission; two spaced-apart and opposite cages sleeved on the lead screw spindle, the cages being adapted to be rotatably mounted in a housing; the planetary rollers directly or indirectly abutting against the two cages and capable of rotating about their own axes; and a transmission wheel connected to the cages; the transmission wheel being capable of rotating about the axis of the lead screw spindle and driving the planetary rollers to rotate together through the cages, thereby driving the lead screw spindle to move axially.

[0006] The beneficial effects of the transmission device proposed in this application are as follows: The planetary rollers directly or indirectly abut against the two cages and can rotate around their own axes, allowing axial force to be transmitted between the lead screw spindle, planetary rollers, cages, and housing, thereby driving the axial movement of the lead screw. Compared to related technologies that require the engagement of planetary rollers with a nut to transmit axial force, the transmission device of this application does not require a nut on the outer circumference of the lead screw spindle, and the planetary rollers do not require threads at both ends to engage with the nut. Therefore, the structure is simpler, occupies less radial and axial space, and has a lower cost.

[0007] Optionally, the cage includes a first groove, and the planetary roller includes a second groove; the transmission device further includes balls, some of which are located in the first groove and some in the second groove; the two cages hold the planetary roller between the two cages via the balls.

[0008] Optionally, the contact between the ball and the first groove, and the contact between the ball and the second groove, can be any one of the following three forms: point contact, line contact, and surface contact.

[0009] Optionally, it also includes thrust bearings, with one thrust bearing installed at each end of each planetary roller, and the two ends of the thrust bearings respectively abutting against the cage and the planetary roller; the planetary rollers are rotatably connected to the two cages respectively.

[0010] Optionally, it also includes two rotating pins, which are fixedly connected to both ends of the planetary roller and coaxial with the planetary roller. The planetary roller is rotatably connected to the two cages respectively through the rotating pins.

[0011] Optionally, the planetary roller includes a first meshing tooth without a helix angle, and the lead screw spindle includes a second meshing tooth with a helix angle. The planetary roller and the lead screw spindle are driven by the meshing of the first meshing tooth and the second meshing tooth.

[0012] Optionally, the meshing distance X of the two planetary rollers arranged circumferentially along the lead screw spindle satisfies: X = (s / 360) * p; where s is the angle formed by the lines connecting the axes of the two planetary rollers to the axis of the lead screw spindle, and p is the lead.

[0013] Optionally, the system may also include a plurality of fasteners for clamping the planetary rollers between the two cages.

[0014] Optionally, the device may also include a plurality of resilient pads disposed between the fastener and the retainer.

[0015] Optionally, the cage further has a plurality of hollow connecting posts arranged circumferentially, and the plurality of fasteners are respectively inserted through the connecting posts so that the two cages clamp the planetary rollers.

[0016] Optionally, the drive wheel has a hollow structure and is sleeved and connected between the two cages.

[0017] Optionally, the drive wheel has axially protruding bosses distributed in the circumferential direction, and the cage has axially protruding third grooves distributed in the circumferential direction. The bosses and the third grooves fit together and abut against each other in the circumferential direction, so that the drive wheel can drive the cage to rotate together.

[0018] Optionally, the outer circumferential surface of the transmission wheel has a third meshing tooth, which is adapted to transmit driving force.

[0019] Optionally, the drive wheel has limiting rings at both ends in the axial direction, the limiting rings being used to define the position of the conveyor belt in the axial direction of the drive wheel.

[0020] Optionally, it also includes a first bearing, one side of which is connected to the cage and the other side of which is adapted to be connected to the housing, for rotatably mounting the cage to the housing and transmitting axial and radial forces.

[0021] Optionally, the first bearing is any one of the following: angular contact bearing, tapered roller bearing, and four-point contact bearing.

[0022] Secondly, a steering gear is proposed, comprising a drive component, a housing, and a transmission device as described above. The drive component is drively connected to the drive wheel, the cage is rotatably mounted on the housing, and the lead screw is adapted to connect to the wheel, adjusting the wheel's steering by axial movement of the lead screw. The steering gear of this application has a compact structure, occupies less space, and has a lower cost.

[0023] Thirdly, a vehicle is proposed that includes a transmission or steering system as described above, having the same beneficial effects.

[0024] Additional aspects and advantages of this application 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 this application. Attached Figure Description

[0025] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 This is a cross-sectional view of the transmission device according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the transmission device according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram showing the point contact between the ball and the cage and the planetary rollers according to one embodiment of this application;

[0029] Figure 4 This is a schematic diagram showing the contact between the balls and the cage and the planetary rollers in one embodiment of this application;

[0030] Figure 5 This is a schematic diagram showing the contact between the ball and the cage and planetary roller surfaces according to one embodiment of this application;

[0031] Figure 6 This is a schematic diagram of a planetary roller connection structure according to another embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the meshing distance between the first meshing teeth of the two planetary rollers in an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of a planetary roller according to an embodiment of this application;

[0034] Figure 9 This is a schematic diagram of the elastic gasket structure according to an embodiment of this application;

[0035] Figure 10 This is a schematic diagram of the support frame structure according to an embodiment of this application;

[0036] Figure 11 This is a schematic diagram of the transmission wheel structure according to an embodiment of this application;

[0037] Figure 12 This is a schematic diagram of the steering gear structure according to an embodiment of this application.

[0038] Figure label:

[0039] Lead screw spindle 1; second meshing tooth 11; planetary roller 2; second groove 21; first meshing tooth 22;

[0040] Cage 3; First groove 31; Connecting post 32; Third groove 33; Transmission wheel 4; Boss 41; Third meshing tooth 42; Limiting ring 43;

[0041] 5. Ball bearing; 6. First bearing; 7. Fastener; 8. Elastic washer; 25. Thrust bearing; 26. Rotating pin;

[0042] Housing 100; Drive unit 200; Conveyor belt 300;

[0043] Steering gear 1000

[0044] Contact point A; contact line B; center of ball 5 P1; center of ball in first groove 31 P2; contact angle α. Detailed Implementation

[0045] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0046] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] To better understand this invention, the background technology will first be described in further detail. In related background technologies, the core components of a planetary roller drive include a lead screw spindle, planetary rollers, a support frame, a drive wheel, and a nut. The planetary rollers are mounted on the support frame and are divided into three sections: the middle section meshes with the lead screw spindle for transmission, and the two end sections mesh with the nut for transmission. The rotation of the drive wheel drives the support frame and the planetary lead screw to rotate. The axial force on the lead screw spindle needs to be provided by the housing through the nut. This technical solution has a complex structure, occupies a large space, and has a high cost.

[0049] To solve the above-mentioned technical problems, this application proposes a transmission device. Please refer to [link / reference needed]. Figure 1 and Figure 2 The transmission device includes: a lead screw spindle 1; a plurality of planetary rollers 2 arranged circumferentially along the lead screw spindle 1 and meshing with the lead screw spindle 1 for transmission; two spaced-apart cages 3 sleeved on the lead screw spindle 1, the cages 3 being rotatably mounted on the housing 100; the planetary rollers 2 directly or indirectly abutting against the two cages 3 and being able to rotate around their own axes; and a transmission wheel 4 connected to the cages 3; the transmission wheel 4 being able to rotate around the axis of the lead screw spindle 1 and drive the planetary rollers 2 to rotate together through the cages 3, thereby driving the lead screw spindle 1 to move axially.

[0050] The planetary rollers 2 directly or indirectly abut against the two cages 3 and can rotate around their own axes, allowing axial force to be transmitted between the lead screw spindle, planetary rollers, cages, and housing, thereby driving the axial movement of the lead screw. Compared to related technologies that require the engagement of planetary rollers and nuts to transmit axial force, the transmission device of this application does not require a nut on the outer circumference of the lead screw spindle, and the planetary rollers do not require threads at both ends to engage with the nut. Therefore, the structure is simpler, occupies less radial and axial space, and has a lower cost.

[0051] See Figure 1 , Figure 8 and Figure 10 According to some embodiments of this application, the cage 3 includes a first groove 31, and the planetary roller 2 includes a second groove 21; the transmission device also includes balls 5, partly located in the first groove 31 and partly located in the second groove 21; the two cages 3 clamp the planetary roller 2 between the two cages 3 by means of the balls 5. This design allows the planetary roller 2 to revolve with the cages, and the balls 5 enable the planetary roller 2 to rotate around its own axis while transmitting axial force. The structure is simple, occupies little space, and has low implementation cost.

[0052] Furthermore, this design allows for adjustments to the contact between the ball 5 and the first groove 31, as well as the contact between the ball 5 and the second groove 21, according to different operating conditions. The contact can be any of three types: point contact, line contact, or surface contact. Among these three contact types, point contact has the lowest load-bearing capacity, lowest friction loss, highest transmission efficiency, and smallest self-locking force; line contact has moderate load-bearing capacity, moderate friction loss, moderate transmission efficiency, and moderate self-locking force; and surface contact has the highest load-bearing capacity, highest friction loss, lowest efficiency, and largest self-locking force. This design is compact and has high space utilization. By designing different contact types for the ball 5, the freedom of rotation of the planetary rollers along their own axes can be released. The planetary rollers 2 convert some of the sliding friction between themselves and the lead screw spindle 1 into rolling friction by rotating along their own axes, reducing system heat generation, lowering the incidence of abnormal noise and other problems, improving system efficiency, and extending system life.

[0053] Specifically, Figure 3 This is a schematic diagram showing the ball 5 in contact with the cage 3 and the planetary roller 2. For example, point A is the contact point between the ball 5 and the cage 3. At this time, the first groove 31 is a spherical surface with a radius greater than that of the ball 5. The center P2 of the first groove 31, the center P1 of the ball 5, and the contact point A are collinear and arranged in sequence.

[0054] Figure 4This diagram illustrates the line contact between the ball 5 and the cage 3 and planetary rollers 2. For example, B is the contact line between the ball 5 and the cage 3, and contact line B is a circular line. The first groove 31 is a curved surface composed of two approximately 1 / 4 spherical surfaces, with the radius of the spheres being larger than the radius of the ball 5. The angle between the line extending from the center P3 of the spheres to the center P1 of the ball 5 and the radial plane is the contact angle α. Adjusting the contact angle α adjusts the circumference of the contact line B; the smaller the contact angle α, the longer the circumference of the contact line B.

[0055] Figure 5 This is a schematic diagram showing the ball 5 in contact with the cage 3 and the planetary roller 2 respectively. At this time, the first groove 31 and the second groove 21 are both spherical surfaces with the same radius as the ball 5 and their centers coincide with the center of the ball 5.

[0056] Of course, the contact form between the ball 5 and the cage 3 can be different from the contact form between the ball 5 and the planetary roller 2. For example, one side can be a point contact and the other side can be a line contact, or one side can be a line contact and the other side can be a surface contact. A combination of the three types of contact can be selected.

[0057] See Figure 6 According to other embodiments of the transmission device of this application, the transmission device includes thrust bearings 25, with one thrust bearing 25 installed at each end of each planetary roller 2. The two ends of the thrust bearings 25 abut against the cage 3 and the planetary roller 2, respectively. The planetary roller 2 is rotatably connected to the two cages 3. This design can also transmit axial force while the planetary roller 2 rotates around its own axis, resulting in a compact structure and small space occupation.

[0058] Specifically, the transmission device may also include two rotating pins 26, which are fixedly connected to both ends of the planetary roller 2 and coaxial with it. The planetary roller 2 is rotatably connected to two cages 3 via the rotating pins 26. The rotating pins 26 can be integral with the planetary roller 2, or they can be fixedly connected by interference fit, bonding, or welding. The rotatable connection between the planetary roller 2 and the cages can be achieved through pin holes containing lubricating grease or bearings. This design is compact, easy to implement, and occupies little space.

[0059] See Figure 1 and Figure 7The planetary roller 2 includes a first meshing tooth 22 without a helix angle, and the lead screw spindle 1 includes a second meshing tooth 11 with a helix angle. The planetary roller 2 and the lead screw spindle 1 are driven by the meshing of the first meshing tooth 22 and the second meshing tooth 11. The rotation of the planetary roller 2 around the lead screw spindle 1 causes axial displacement of the lead screw spindle 1. The planetary roller 2 can also rotate around its own axis. Due to the friction between the planetary roller 2 and the lead screw spindle 1, the planetary roller 2 will rotate, converting the sliding friction between the planetary roller 2 and the lead screw spindle 1 into rolling friction. This reduces system heat generation, improves transmission efficiency, and reduces abnormal noise.

[0060] Furthermore, the meshing distance X of the two planetary rollers 2 arranged circumferentially along the lead screw spindle 1 satisfies: X = (s / 360) * p; where s is the angle formed by the lines connecting the axes of the two planetary rollers to the axis of the lead screw spindle, and p is the lead. This results in higher transmission accuracy and more stable transmission.

[0061] See Figure 1 and Figure 2 The transmission device may also include multiple fasteners 7, which are used to clamp the planetary rollers 2 between the two cages 3. The fasteners 7 may be bolts, screws, studs, or pins, etc.

[0062] Further, see Figure 1 and Figure 9 The transmission device may also include multiple elastic washers 8, which are disposed between the fastener 7 and the cage 3. These washers apply an initial preload, increasing the rigidity of the transmission device and reducing the clearance under load. Furthermore, when axial parts of the transmission device experience wear, the compression of the elastic washers 8 can be released to compensate for the clearance. This reduces the likelihood of cage 3 swaying during load transmission, maintains system stability, reduces the probability of abnormal noise, and extends system life. Specifically, the elastic washers 8 can be corrugated washers, adjusting axial force and clearance through their own deformation, offering a wide adjustment range.

[0063] See Figure 10 The cage 3 may also have multiple hollow connecting posts 32 arranged circumferentially, with multiple fasteners 7 correspondingly passing through the connecting posts 32 so that the two cages 3 clamp the planetary rollers 2. The connecting posts 32 make the positioning of the fasteners more accurate and reduce the leakage of transmission grease from the fasteners.

[0064] Specifically, four connecting posts 32 can be evenly arranged around the circumference of the retainer 3, with two diagonally opposite connecting posts 32 being through holes, and the other two diagonally opposite connecting posts 32 having threads at the ends away from the opposite retainers 3. In two spaced-apart retainers 3, the two through-hole connecting posts 32 of one retainer 3 correspond to the two threaded connecting posts 32 of the other retainer 3, with a gap between the corresponding connecting posts 32, and bolts passing through the two corresponding connecting posts.

[0065] See Figure 1 and Figure 11 The drive wheel 4 has a hollow structure and is fitted between two cages 3. This structure is more compact and occupies less axial space.

[0066] Furthermore, the drive wheel 4 has axially protruding bosses 41 distributed in the circumferential direction, and the retainer 3 has axially protruding third grooves 33 distributed in the circumferential direction. The bosses 41 and the third grooves 33 fit together and abut against each other in the circumferential direction, so that the drive wheel 4 can drive the retainer 3 to rotate together. This makes the circumferential connection between the drive wheel 4 and the retainer 3 more reliable.

[0067] Specifically, the outer circumferential surface of the transmission wheel 4 may have a third meshing tooth 42, which is suitable for transmitting driving force. This makes the transmission more reliable and avoids slippage.

[0068] Specifically, the drive wheel 4 has limiting rings 43 at both ends in the axial direction. The limiting rings 43 are used to limit the position of the conveyor belt 300 in the axial direction of the drive wheel 4, so as to make the transmission more stable. The limiting rings 43 can be integrally formed with the drive wheel 4 or can be installed on the drive wheel, which is not limited here.

[0069] See Figure 1 The transmission device may also include a first bearing 6, one side of which is connected to the cage 3, and the other side of which is adapted to be connected to the housing 100, for rotatably mounting the cage 3 to the housing 100 and transmitting axial and radial forces. In this way, the structure is more compact and reliable.

[0070] The first bearing 6 can be any of the following types of bearings: angular contact bearing, tapered roller bearing, and four-point contact bearing, etc.

[0071] Figure 11 This is a schematic diagram of a steering gear according to an embodiment of this application. The steering gear 1000 includes a drive member 200, a housing 100, and a transmission device as described above. The drive member 200 is connected to the drive wheel 4. The retainer 3 is rotatably mounted on the housing 100. The lead screw spindle 1 is adapted to connect to the wheel, and the steering of the wheel is adjusted by the axial movement of the lead screw spindle 1. This steering gear has a compact structure, occupies less space, and has a low cost.

[0072] Specifically, the steering gear may include a toothed drive belt 300, a drive member 200 with a toothed shaft, and a drive pulley 4 with a third meshing tooth 42. The shaft of the drive member 200 meshes with the drive belt 300 for transmission, and the drive belt 300 meshes with the drive pulley 4 for transmission, thereby achieving a transmission connection between the drive member 200 and the drive pulley 4. Of course, other transmission methods such as gear and rack transmission and chain transmission can also be used. The lead screw spindle 1 can be connected to the wheel through components such as connecting rods, forks, and anti-rotation mechanisms to convert the rotational motion of the motor into linear displacement motion, pushing the tire to rotate along a certain axis to achieve wheel steering.

[0073] Accordingly, this application also proposes a vehicle including the aforementioned transmission or steering system, having the same beneficial effects as the aforementioned transmission or steering system. The vehicle can be any energy form, such as a gasoline vehicle, an electric vehicle, or a hybrid vehicle.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A transmission device, characterized in that, include: Lead screw spindle (1); Several planetary rollers (2) are arranged circumferentially along the lead screw spindle (1) and mesh with the lead screw spindle (1) for transmission. Two spaced-apart cages (3) are fitted onto the lead screw spindle (1), and the cages (3) are adapted to be rotatably mounted on the housing (100); the planetary rollers (2) directly or indirectly abut against the two cages (3) and can rotate around their own axis; The transmission wheel (4) is connected to the cage (3); the transmission wheel (4) can rotate around the axis of the lead screw spindle (1) and drive the planetary rollers (2) to rotate together through the cage (3) so as to drive the lead screw spindle (1) to move axially.

2. The transmission device according to claim 1, characterized in that, The cage (3) includes a first groove (31), and the planetary roller (2) includes a second groove (21); the transmission device also includes a ball (5), which is partially located in the first groove (31) and partially located in the second groove (21); the two cages (3) clamp the planetary roller (2) between the two cages (3) through the ball (5).

3. The transmission device according to claim 2, characterized in that, The contact between the ball (5) and the first groove (31), and the contact between the ball (5) and the second groove (21) are any of the following three forms: point contact, line contact, and surface contact.

4. The transmission device according to claim 1, characterized in that, It also includes thrust bearings (25), with one thrust bearing (25) installed at each end of each planetary roller (2), and the two ends of the thrust bearings (25) abutting against the cage (3) and the planetary roller (2) respectively; the planetary roller (2) is rotatably connected to the two cages (3) respectively.

5. The transmission device according to claim 4, characterized in that, It also includes two rotating pins (26), which are fixedly connected to both ends of the planetary roller (2) and coaxial with the planetary roller (2). The planetary roller (2) is rotatably connected to the two cages (3) respectively through the rotating pins (26).

6. The transmission device according to any one of claims 1-5, characterized in that, The planetary roller (2) includes a first meshing tooth (22) without a helix angle, and the lead screw spindle (1) includes a second meshing tooth (11) with a helix angle. The planetary roller (2) and the lead screw spindle (1) are driven by the meshing of the first meshing tooth (22) and the second meshing tooth (11).

7. The transmission device according to claim 6, characterized in that, The meshing distance X of the two planetary rollers (2) arranged circumferentially along the main shaft (1) of the lead screw satisfies: X = (s / 360) * p; where s is the angle formed by the lines connecting the axes of the two planetary rollers to the axis of the main shaft of the lead screw, and p is the lead.

8. The transmission device according to any one of claims 1-5, characterized in that, It also includes a plurality of fasteners (7) for clamping the planetary rollers (2) by the two cages (3).

9. The transmission device according to claim 8, characterized in that, It also includes a plurality of elastic pads (8) disposed between the fastener (7) and the retainer (3).

10. The transmission device according to claim 8, characterized in that, The cage (3) also has a plurality of hollow connecting posts (32) arranged circumferentially, and the plurality of fasteners (7) are respectively inserted through the connecting posts (32) so that the two cages (3) clamp the planetary rollers (2).

11. The transmission device according to any one of claims 1-5, characterized in that, The transmission wheel (4) has a hollow structure and is sleeved between the two retainers (3).

12. The transmission device according to claim 11, characterized in that, The drive wheel (4) has axially protruding bosses (41) distributed in the circumferential direction, and the retainer (3) has axially distributed third grooves (33) in the circumferential direction. The bosses (41) fit into the third grooves (33), and the bosses (41) and the third grooves (33) abut against each other in the circumferential direction, so that the drive wheel (4) can drive the retainer (3) to rotate together.

13. The transmission device according to claim 11, characterized in that, The outer circumferential surface of the transmission wheel (4) has a third meshing tooth (42), which is suitable for transmitting driving force.

14. The transmission device according to claim 13, characterized in that, The drive wheel (4) has limiting rings (43) at both ends in the axial direction, and the limiting rings (43) are used to limit the position of the conveyor belt (300) in the axial direction of the drive wheel (4).

15. The transmission device according to claim 1, characterized in that, It also includes a first bearing (6), one side of which is connected to the cage (3) and the other side of which is adapted to be connected to the housing (100) for rotatably mounting the cage (3) on the housing (100) and for transmitting axial and radial forces.

16. The transmission device according to claim 15, characterized in that, The first bearing (6) is any one of the following bearings: angular contact bearing, tapered roller bearing and four-point contact bearing.

17. A steering gear (1000), characterized in that, The device includes a drive unit (200), a housing (100), and a transmission device as described in any one of claims 1-16, wherein the drive unit (200) is connected to the transmission wheel (4), the cage (3) is rotatably mounted on the housing (100), and the lead screw spindle (1) is adapted to be connected to the wheel, and the steering of the wheel is adjusted by the axial movement of the lead screw spindle (1).

18. A vehicle, characterized in that, Includes the transmission device as described in any one of claims 1-16 or the steering device as described in claim 17.

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