WO2022219429A1

WO2022219429A1 - Connector, motor vehicle steering gear comprising same, and motor vehicle

Info

Publication number: WO2022219429A1
Application number: PCT/IB2022/052428
Authority: WO
Inventors: Zengchao JIAO; Mingfei FENG; Zhaoming ZONG
Original assignee: Robert Bosch Automotive Steering Jinan Co., Ltd.
Priority date: 2021-04-16
Filing date: 2022-03-17
Publication date: 2022-10-20
Also published as: CN113335369B; CN113335369A

Abstract

The present invention relates to a connector, a motor vehicle steering gear comprising same, and a motor vehicle. The connector has a first end and a second end opposite each other, the first end and the second end being aligned in an axial direction of the connector, and the connector has a first spline and a second spline, wherein the first spline extends from the first end toward the second end, and the second spline extends from the second end toward the first end.

Description

Connector, motor vehicle steering gear comprising same, and motor vehicle

Technical field

[0001] The present invention relates to the technical field of motor vehicle production; in particular, the present invention relates to a connector, and further relates to a motor vehicle steering gear comprising same, and a motor vehicle.

Background art

[0002] Motor vehicles are a common means of transportation in modern life.

[0003] The steering gear of a motor vehicle is an important component of the motor vehicle’s steering system; the function thereof is to increase the force or torque transmitted from the steering wheel to the steering drive mechanism, and change the direction of transmission of the force or torque. When the driver performs a steering operation on the motor vehicle by means of the steering wheel, it can provide steering assistance, reducing the force required from the driver to operate the steering wheel, so that driving is more relaxed and convenient for the driver.

[0004] In general, in the motor vehicle steering gear, an output shaft of an electric drive unit and a steering screw of a steering gear body are joined together directly.

Summary of the invention [0005] An object of one aspect of the present invention is to provide an improved connector.

[0006] An object of another aspect of the present invention is to provide a motor vehicle steering gear comprising the connector.

[0007] An object of another aspect of the present invention is to provide a motor vehicle comprising the motor vehicle steering gear.

[0008] To achieve the above objects, one aspect of the present invention provides a connector, wherein the connector has a first end and a second end opposite each other, the first end and the second end being aligned in an axial direction of the connector, and the connector has a first spline and a second spline, wherein the first spline extends from the first end toward the second end, and the second spline extends from the second end toward the first end.

[0009] Optionally, in the connector as described above, the first spline and the second spline each extend partially along the connector, or the first spline and the second spline each extend all the way along the connector between the first end and the second end.

[0010] Optionally, in the connector as described above, the first spline and the second spline are located on an outer peripheral face of the connector, or the first spline and the second spline are located on an inner peripheral face of the connector, or the first spline and the second spline are located on an inner peripheral face and an outer peripheral face of the connector respectively.

[0011] Optionally, in the connector as described above, the sum of a length of extension of the first spline and a length of extension of the second spline is less than a length of the connector.

[0012] Optionally, in the connector as described above, process grooves are provided at an end of the first spline that is remote from the first end and at an end of the second spline that is remote from the second end. [0013] Optionally, in the connector as described above, the first spline and the second spline provide a cross-shaped key slot or a toothed key slot for the connector.

[0014] To achieve the above objects, one aspect of the present invention provides a motor vehicle steering gear, wherein the motor vehicle steering gear comprises an electric drive unit and a steering gear body, the electric drive unit having an output shaft, the steering gear body having a steering screw, and the output shaft being connected to the steering screw via the connector as described in any element of the aspect above.

[0015] Optionally, in the motor vehicle steering gear as described above, an end of the steering screw is provided with a spline that engages with the first spline, and the output shaft of the electric drive unit is provided with a spline that engages with the second spline, and a washer is provided in at least one of a process groove of the spline on the steering screw and a process groove of the spline on the output shaft.

[0016] Optionally, in the motor vehicle steering gear as described above, process grooves are provided at an end of the first spline that is remote from the first end and at an end of the second spline that is remote from the second end, and a washer is arranged in at least one of the process grooves.

[0017] Optionally, in the motor vehicle steering gear as described above, the steering gear body comprises a housing, and a steering nut is arranged in the housing; the steering nut is fitted round the steering screw and meshed with the steering screw, thus being movable in an axial direction of the steering screw under the rotational driving action of the steering screw.

[0018] Optionally, in the motor vehicle steering gear as described above, internal cavity parts at two ends of the steering nut are in fluid communication with each other. [0019] To achieve the above objects, one aspect of the present invention provides a motor vehicle, wherein the motor vehicle has the motor vehicle steering gear as described in any element of the aspect above.

Brief description of the drawings

[0020] The disclosed content of the present invention will become more obvious with reference to the drawings. It should be understood that these drawings are merely intended for explanatory purposes, and not intended to limit the scope of protection of the present invention. In the drawings:

Fig. 1 is a schematic sectional view of a motor vehicle steering gear according to an embodiment of the present invention.

Fig. 2 is a schematic partial sectional view of the connector region in the motor vehicle steering gear in Fig. 1.

Fig. 3 is a schematic exploded drawing of the connector region in Fig. 2.

Fig. 4 is a schematic sectional view of a motor vehicle steering gear according to another embodiment of the present invention; and

Fig. 5 is a schematic exploded view of the connector region in Fig. 4.

Detailed description of embodiments

[0021] Particular embodiments of the present invention are described in detail below with reference to the drawings. In the drawings, identical reference labels indicate identical or corresponding technical features. In addition, for clarity, technical features present in a quantity greater than one might only be labelled at one position or a number of positions in the same drawing.

[0022] It will be understood that although a description is given herein in conjunction with a limited number of embodiments, those skilled in the art could expand, modify, replace and/or combine technical features on this basis. Thus, the content herein is descriptive, and should not be regarded as limiting the scope of the present invention.

[0023] Fig. 1 is a schematic sectional view of a motor vehicle steering gear according to an embodiment of the present invention. [0024] As shown in Fig. 1, the motor vehicle steering gear 100 may comprise an electric drive unit 110 and a steering gear body 120.

[0025] The electric drive unit 110 detects movement parameters, e.g. speed and angle, etc., of a torque input shaft 111, controls and adjusts an output torque of a drive electric motor according to a detection signal, and transmits the torque of the drive electric motor (on which a torque of the torque input shaft 111 may also be superimposed) to a steering screw of the motor vehicle steering gear 100. A drive torque of the torque input shaft 111 comes from a manual operation of a driver.

[0026] The steering gear body 120 comprises a housing 121, a steering screw 122 installed in the housing 121, and a steering nut 123 arranged in the housing 121. The steering nut 123 is fitted round the steering screw 122 and meshed therewith, such that the steering nut 123 can move in an axial direction of the steering screw under the rotational driving action of the steering screw 122, and the steering nut 123 can drive a fan-shaped gearwheel 124 on an output shaft.

An internal cavity of the housing 121 is divided by the steering nut 123 into two internal cavity parts at two ends. The internal cavity parts at two ends of the steering nut 123 are in fluid communication with each other. A helical raceway having balls is present between the steering screw 122 and the steering nut 123; when rotating, the steering screw 122 can push the steering nut 123 to move to the left or right by means of these balls. Teeth on a peripheral side of the steering nut 123 in turn drive the fan-shaped gearwheel 124, the fan-shaped gearwheel 124 drives the output shaft of the steering gear to rotate left or right, and force and torque are subsequently conveyed to the vehicle wheels by means of a rod system, thereby steering the vehicle wheels.

[0027] In the embodiment of Fig. 1, an output shaft 112 of the electric drive unit 110 is connected to the steering screw 122 of the steering gear body 120 by means of a connector 200. The connector 200 is configured to transmit torque between the output shaft 112 and the steering screw 122. The connector 200 is movable relative to the output shaft 112 and the steering screw 122. [0028] The connector 200 may have a first end 210 and a second end 220 opposite each other; the first end 210 and second end 220 may be aligned in an axial direction of the connector 200. First splines 211 are provided at the first end 210, and second splines 221 are provided at the second end 220, for connection to the steering screw 122 of the steering gear body 120 and the output shaft 112 of the electric drive unit 110 respectively.

[0029] As shown in the figures, the connector 200 may be straight in form; moreover, an end thereof close to the electric drive unit 110 is a hollow part, while an end thereof close to the steering gear body 120 is a solid part. In order to save material, removal of some of the material in the solid part may also be considered, without affecting the operational performance of the connector. The first splines 211 are located on an outer peripheral face of the connector 200 at the solid part, and the second splines 221 are located on an inner peripheral face of the connector 200 at the hollow part. Outside extremities of the first splines 211 and the second splines 221 may take the form of sloping guide faces, to facilitate the fitting thereof to adjacent components.

[0030] A connecting end of the output shaft 112 of the electric drive unit 110 is inserted into the hollow part of the connector 200 and spline-connected to the second end 220; an end of the steering screw 122 is a recess and has internal splines, and is fitted round the first end 210 of the connector 200 and spline- connected to the first end 210. Outermost extremities of external splines of the connecting end of the output shaft 112 and outermost extremities of the internal splines in the recess of the steering screw may also take the form of sloping guide faces, in order to guide the engagement thereof with the splines on the connector 200. An outer diameter of the connector 200 may be slightly smaller than an inner diameter of the recess of the steering screw 122, in order to provide it with a relative radial movement gap.

[0031] At the same time, it can be seen more clearly by referring to the sectional view in Fig. 3 that the connector 200 has first splines 211 and second splines 221. The first splines 211 extend from the first end 210 toward the second end 220, and the second splines 221 extend from the second end 220 toward the first end 210. As stated above, the first splines 210 are formed on an outer circumference of the solid part, and the second splines 221 are formed on an inner circumference of the hollow part.

[0032] In the embodiment shown in the figures, an extension portion 230 is also provided on the connector, between the part having the first splines 211 and the part having the second splines 221. In different embodiments, the extension portion 230 may be configured to be longer or shorter, or may be eliminated. In addition, in some embodiments, depending on specific requirements, the first splines 211 and second splines 221 may be staggered and not interfere with each other, and can likewise be used for connection between the electric drive unit and the steering gear body.

[0033] In the embodiment shown in the figures, the first splines 211 and the second splines 221 extend partially along the connector 200. In a different embodiment, the first splines and second splines may also be designed to extend all the way along the connector 200 between the first end 210 and the second end 220, i.e. extend over the entire length in the axial direction of the connector 200.

[0034] In the embodiment shown in the figures, the first splines 211 are located on the outer peripheral face of the connector 200, and the second splines 221 are located on the inner peripheral face of the connector 200. Based on this embodiment, those skilled in the art can alter the form thereof; in different embodiments, a design is also possible whereby the first splines and the second splines are both located on the outer peripheral face of the connector, or the first splines and the second splines are both located on the inner peripheral face of the connector, or the first splines are located on the inner peripheral face of the connector while the second splines are located on the outer peripheral face of the connector. In use, the end of the steering screw 122 of the steering gear body 120 and the output shaft 112 of the electric drive unit 110 may have matching spline designs.

[0035] In the embodiment shown in the figures, the sum of the length of extension of the first splines 211 and the length of extension of the second splines 221 is less than the length of the connector 200, such that the extension portion 230 is present between the first splines 211 and the second splines 221.

In different embodiments, the sum of the length of the first splines 211 and the length of the second splines 221 may be equal to or greater than the length of the connector 200. When the first splines 211 and the second splines 221 are identically located on the outer peripheral face or inner peripheral face, if the sum of the length of the first splines and the length of the second splines is greater than the length of the connector 200, then the first splines 211 and second splines 221 are staggered with respect to each other, and may be designed so that they do not interfere with each other; consequently, the respective engagement of the electric drive unit (via the output shaft) and the steering gear body (via the steering screw) with them will not be affected.

[0036] As shown in the figure, process grooves are provided at the end of the first splines 211 that is remote from the first end (i.e. between the first splines 211 and the smooth outer peripheral face of the connector) and at the end of the second splines 221 that is remote from the second end (i.e. between the second splines 221 and an inner end of the connector). The process groove may serve as a cutter withdrawal groove when the splines are being machined. In addition, when the connector 200 is connected between the electric drive unit 110 and the steering gear body 120, a washer 300 may be arranged in the process groove, wherein the form of the washer is for example an O-ring, etc., but is not limited thereto; the washer can serve the function of defining the relative connection position of the connector 200 relative to the end of the steering screw 122 of the steering gear body 120 and the output shaft 112 of the electric drive unit 110.

[0037] Splines 125 are provided on the inside of the steering screw 122 of the steering gear body 120, and a shoulder 126 is formed in the recess of the end of the steering screw 122, at the outermost end of the splines 125. When the first splines 211 are inserted into the recess of the end of the steering screw 122, the first splines 211 engage with the splines 125 therein, and at the same time, an O- ring at the first splines 211 engages with the shoulder 126; this can be seen in Figs. 1 and 2.

[0038] Fig. 2 is a schematic partial sectional view of the connector region in the motor vehicle steering gear in Fig. 1. The connection of the output shaft 112 of the electric drive unit 110 to the connector 200, and the connection of the steering screw 122 of the steering gear body 120 to the connector, are shown more clearly in the figure.

[0039] As can be seen from the figure, a left end of the connector 200 (i.e. the end having the first splines) is engaged with the splines in the recess of the steering screw 122, and a right end of the connector 200 (i.e. the end having the second splines) is engaged with the splines at the extremity of the output shaft 112. Here, the engagement of splines may be a loose fit with a slight gap, in order to provide an appropriate gap for movement in a radial direction. An O- shaped washer 300 is provided at the cutter withdrawal groove of the first splines 211; the washer is engaged with the shoulder in the recess of the steering screw, i.e. is configured to define a spline engagement depth, while also preventing rigid impact, thus avoiding excessive wear and noise. The splines in the recess of the steering screw 122 may also have a process groove at an inside end thereof.

[0040] In the figure, the output shaft 112 of the electric drive unit 110 and the steering screw 122 of the steering gear body 120 are each connected to the connector 200. The three parts may be connected coaxially; this is beneficial for the service life of each connecting part. The output shaft 112 outputs torque to the steering screw 122 via the connector 200.

[0041] Fig. 3 is a schematic exploded drawing of the connector region in Fig. 2. The first splines 211, the second splines 221, the splines 125 in the steering screw 122 and the splines on the output shaft 112 are shown more clearly in Fig. 3. The process groove at the first splines 211 and a process groove at the output shaft 112, etc., are also shown more clearly in the figure. Depending on requirements, O-shaped washers may be arranged at these process grooves.

[0042] When the connector for transmitting torque is arranged between the output shaft of the electric drive unit and the steering screw of the steering gear body, it can overcome at least one of the following problems associated with a direction connection between the output shaft and the steering screw: (1) When assembly is performed, in addition to positioning of the output shaft and the steering screw relative to each other, the use of a positioning hole to position the electric drive unit and the steering gear body relative to each other is also involved; multi-point positioning requires high component processing precision and assembly precision, thus increasing costs. (2) When the steering screw is subjected to a radial force, one end thereof will shift upward or downward, and will easily become jammed or experience friction or stress at the position of connection to the output shaft; thus, there are potential problems of wear and breakage, which will affect the service life.

[0043] In embodiments of the present invention, as shown in the figures it comprises an independent connector, which is separately connected to the end of the output shaft of the electric drive unit and the end of the steering screw of the steering gear body. Because there is a slight gap (for example at each splined connection) in the connection of the connector to the end of the output shaft and the end of the steering screw, the connector can have the effect of compensating for movement when one or both ends of the steering screw moves upward or downward, and can achieve one or more of the following technical effects: lowering the processing precision and assembly precision requirements for each component, preventing a force at the junction of the steering screw and the connector from being transmitted to the junction of the electric drive unit and the connector, preventing local stress at the junctions, and avoiding potential risks affecting the service life of each component.

[0044] Fig. 4 is a schematic sectional view of a motor vehicle steering gear according to another embodiment of the present invention. Fig. 5 is a schematic exploded view of the connector region in Fig. 4. The connector is configured to transmit torque between the output shaft 112 of the electric drive unit and the steering screw of the steering gear body.

[0045] A connector 400 connected between the electric drive unit 110 and the steering gear body 120 is shown in Fig. 4. The connector is movable relative to the output shaft of the electric drive unit and the steering screw of the steering gear body. As can be seen by referring to Fig. 5, the connector 400 has a cylindrical outer peripheral face, and has a cross-shaped key slot in the interior thereof. It will be understood that the cylindrical outer peripheral face is easy to process, but the outer peripheral face of the connector 400 may also have other shapes depending on the particular situation.

[0046] Here, the technical concept of the cross-shaped key slot is the same as that of the connector 200 in Figs. 1 - 3. The cross-shaped key slot is formed by arranging two straight key slots in such a way that they intersect perpendicularly; the two straight key slots each extend in a penetrating fashion from two ends of the connector 400 to the opposite ends in an axial direction of the connector. Correspondingly, each of the keys forming the key slot corresponds to a spline formed of only one key, and each extends from one end of the connector 400 to the other end.

[0047] In order to mate with the connector 400 having the cross-shaped key slot, straight keys 127, 113 are formed at an end of the steering screw 122 and an end of the output shaft 112 respectively, and slots are formed in respective middle parts of the straight keys 127, 113. The straight keys 127 and 113 are adapted to extend into the cross-shaped key slot of the connector 400 from the two ends of the connector 400 respectively. After the straight key 127 and the straight key 113 have come together in the cross-shaped key slot, because they each have a slot formed in the middle part thereof, extending key parts at two sides of the slots of the straight keys 127 and 113 can all pass through and fully engage with the cross-shaped key slot of the connector 400. Another way of looking at this is that in the course of assembly, the straight keys 127 and 113 are plugged together and sheathed by the cross-shaped key slot of the connector 400, and are thus able to serve the function of transmitting motion. At this time, even if there is error or fluctuation during driving in a circumferential direction, both ends can push the connector to rotate, and can serve the function of, for example but without limitation, compensating for the error, etc.

[0048] In another embodiment, the connector may also be designed to have a key slot that has the shape of an eight-pointed figure or has teeth in another form. In this case, the end of the steering screw 122 and the end of the output shaft 112 have suitably matched keys or splines, and slots may also be provided in middle parts of these keys or splines to facilitate complete fitting. [0049] Based on the foregoing description of various embodiments of the connector, the present invention further provides a motor vehicle steering gear comprising any one of the connectors in the various embodiments above. The motor vehicle steering gear may comprise a steering gear body and an electric drive unit, with a steering screw of the steering gear body being connected to an output shaft of the electric drive unit via the connector described above. The connector is movable, i.e. can float, relative to the steering screw and the output shaft. Specifically, an end of the steering screw may be provided with splines adapted to engage with the first splines, and the output shaft of the electric drive unit may be provided with splines adapted to engage with the second splines. When the connector comprises a cross-shaped key slot or a toothed key slot in the shape of an eight-pointed figure or star, etc., the end of the steering screw and an end of the output shaft may be a corresponding straight key or a key of a different form. In the case where process grooves are provided at each position where splines are disposed, a washer may be arranged in the corresponding process groove. For example, as shown in Figs. 1 and 2, a washer may be provided in one of the process groove of the splines on the steering screw and the process groove of the splines on the output shaft; and/or process grooves are provided at the end of the first splines that is remote from the first end and at the end of the second splines that is remote from the second end, with a washer being arranged in at least one process groove. In addition, in the example shown in the figure, the connector may be located in a hole in an end wall of the steering gear body, to assist with the positional support and stability thereof, maintaining axial alignment with the output shaft of the electric drive unit and the steering screw of the steering gear body at all times, which helps to extend the service life thereof.

[0050] When the motor vehicle steering gear having the connector according to various embodiments of the present invention is assembled, the installation steps that may be considered include: assembling the steering gear body, including fitting the steering screw and steering nut, etc., thereof; fitting the connector into the hole in the end wall of the steering gear body, such that it is connected to the end of the steering screw; mounting the electric drive unit to the steering gear body (for example but without limitation, using bolts, etc.), at the same time connecting the connector to the end of the output shaft of the electric drive unit. The connector may be connected to the output shaft of the electric drive unit and the steering screw of the steering gear body in a floating manner.

[0051] Furthermore, another aspect of the present invention further provides a motor vehicle comprising the connector and/or motor vehicle steering gear according to any one of the embodiments above. It will be understood that corresponding motor vehicle types may be various vehicle types comprising a steering system, for example but not limited to a family car, a transportation truck, etc.

[0052] As stated above, the connector, the motor vehicle steering gear comprising same, and the motor vehicle according to a number of embodiments of the present invention are described herein. It should be understood that the scope claimed by the present invention is not limited to the content described above. Those skilled in the art could carry out various expansions, modifications, replacements and/or combinations of the embodiments above without departing from the technical concept of the present invention, and all such expansions, modifications, replacements and/or combinations should be included in the scope claimed by the present invention.

Claims

1. A connector, characterized in that the connector has a first end and a second end opposite each other, the first end and the second end being aligned in an axial direction of the connector, and the connector has a first spline and a second spline, wherein the first spline extends from the first end toward the second end, and the second spline extends from the second end toward the first end.

2. The connector as claimed in claim 1, wherein the first spline and the second spline each extend partially along the connector, or the first spline and the second spline each extend all the way along the connector between the first end and the second end.

3. The connector as claimed in claim 1, wherein the first spline and the second spline are located on an outer peripheral face of the connector, or the first spline and the second spline are located on an inner peripheral face of the connector, or the first spline and the second spline are located on an inner peripheral face and an outer peripheral face of the connector respectively.

4. The connector as claimed in claim 1, wherein the sum of a length of extension of the first spline and a length of extension of the second spline is less than a length of the connector.

5. The connector as claimed in claim 4, wherein process grooves are provided at an end of the first spline that is remote from the first end and at an end of the second spline that is remote from the second end.

6. The connector as claimed in claim 1, wherein the first spline and the second spline provide a cross-shaped key slot or a toothed key slot for the connector.

7. A motor vehicle steering gear, characterized in that the motor vehicle steering gear comprises an electric drive unit and a steering gear body, the electric drive unit having an output shaft, the steering gear body having a steering screw, and the output shaft being connected to the steering screw via the connector as claimed in any one of claims 1 - 6.

8. The motor vehicle steering gear as claimed in claim 7, wherein an end of the steering screw is provided with a spline that engages with the first spline, and the output shaft of the electric drive unit is provided with a spline that engages with the second spline, and a washer is provided in at least one of a process groove of the spline on the steering screw and a process groove of the spline on the output shaft.

9. The motor vehicle steering gear as claimed in claim 7, wherein process grooves are provided at an end of the first spline that is remote from the first end and at an end of the second spline that is remote from the second end, and a washer is arranged in at least one of the process grooves.

10. The motor vehicle steering gear as claimed in claim 7, wherein the steering gear body comprises a housing, and a steering nut is arranged in the housing; the steering nut is fitted round the steering screw and meshed with the steering screw, thus being movable in an axial direction of the steering screw under the rotational driving action of the steering screw.

11. The motor vehicle steering gear as claimed in claim 10, wherein internal cavity parts at two ends of the steering nut are in fluid communication with each other.

12. A motor vehicle, characterized in that the motor vehicle has the motor vehicle steering gear as claimed in any one of claims 7 - 11.