Three-ball joint coupling and steering mechanism

Abstract

A three-ball-pin coupling includes a first coupling (M) and a second coupling (N) that are not rotatably connected relative to each other. The first coupling (M) includes a three-pin assembly (10), a raceway assembly (20), and a cage assembly (30). The three-pin assembly (10) includes a shaft (11) and three ball rings (13) spaced apart circumferentially around the shaft (11). There are three raceway assemblies (20), each ball ring (13) connected to one raceway assembly (20). The cage assembly (30) defines the circumferential position of the raceway assembly (20) and provides an elastic force between the ball rings (13) and the cage assembly (30). When the ball rings (13) are displaced relative to the cage assembly (30) in the circumferential direction, the raceway assembly (20) remains in contact with the cage assembly (30) on both sides in the circumferential direction. A steering mechanism is also provided.

Description

Technical Field

[0001] This invention relates to the field of couplings, and particularly to a three-ball-pin coupling for vehicle steering mechanisms. Background Technology

[0002] For vehicle steering mechanisms, especially electric power steering mechanisms, worm gear transmission is typically used to amplify the torque of the motor and drive the rack to complete the steering. Such steering mechanisms include, for example, column-type and double pinion-type steering mechanisms.

[0003] A common worm gear system in the aforementioned steering mechanism uses a coupling to connect the motor's output shaft and the worm shaft. These components are interconnected in a male-female shaft configuration, enabling the transmission of motor torque. The motor torque is further transmitted and amplified by the meshing worm gears to drive other components in the entire steering system.

[0004] The support portion of the aforementioned worm gear system includes a self-aligning bearing on one side of the worm and a deep groove ball bearing on the other side. To ensure continuous and stable meshing of the worm gear system, a spring is arranged perpendicular to the meshing axis of the worm gear at the location where the deep groove ball bearing is installed.

[0005] For example, in a worm gear with a transmission ratio of 2:1, assuming the motor torque is 5 Nm, the torque transmitted to the worm gear through the coupling is approximately 100 Nm (considering efficiency losses during torque transmission), resulting in a driving force of approximately 10 kN on the rack. This torque is used to drive the wheel to complete the steering action. Typically, to transmit torque quietly, the contact surface between the worm gear and the worm is made of engineering plastic. Over time, this plastic contact surface will wear down. At this point, the worm axis will shift at a certain angle under the action of spring force (the maximum displacement is usually + / - 1.5°). This adjustment ensures that the meshing quality of the worm gear remains approximately the same before and after wear.

[0006] However, as the output torque of the motor increases (e.g., from 5 Nm to 8 Nm) to accommodate vehicles with higher loads, the plastic surface of the worm gear will experience greater surface wear after durability, thus requiring the worm to have a larger axial offset (compensation) angle.

[0007] The self-aligning bearing located on one side of the worm gear can more easily achieve a larger self-aligning angle, but the self-aligning capability of the coupling located between the motor and the worm gear is usually limited. Once the offset angle of the worm gear axis exceeds the compensation capacity of the coupling design, the system is prone to a series of problems such as vibration and noise, torque transmission lag, and wear of the mating teeth forming gaps.

[0008] Therefore, it is urgent to expand the self-aligning angle compensation range of the coupling while ensuring torsional stiffness. Summary of the Invention

[0009] The purpose of this invention is to overcome or at least mitigate the shortcomings of the prior art and to provide a three-ball pin coupling and a steering mechanism.

[0010] According to a first aspect of the invention, a three-ball-pin coupling is provided, comprising a first connecting member and a second connecting member that cannot be rotatably connected relative to each other, wherein...

[0011] The first connecting member includes a three-pin assembly, a raceway assembly, and a cage assembly.

[0012] The three-pin assembly includes a shaft and three ball rings spaced apart circumferentially around the shaft. There are three raceway assemblies, with each ball ring connected to one raceway assembly. The cage assembly defines the position of the raceway assemblies in the circumferential direction.

[0013] The raceway assembly provides an elastic force between the ball ring and the cage assembly, and the raceway assembly remains in contact with the cage assembly on both sides of the circumferential direction when the ball ring is displaced relative to the cage assembly in the circumferential direction.

[0014] In at least one embodiment, the raceway assembly includes a raceway frame, an inner raceway, an outer raceway, and an elastic element.

[0015] Each raceway frame is equipped with two inner raceways and two outer raceways. The two inner raceways are spaced apart to form a ball ring mounting portion between them. Each inner raceway has an outer raceway mounted on its side away from the ball ring mounting portion. An inner raceway and an outer raceway on the same side of the ball ring mounting portion form a raceway pair.

[0016] The elastic element is at least partially disposed between the inner raceway and the outer raceway, and the elastic element abuts against both the inner raceway and the outer raceway of each raceway pair.

[0017] In at least one embodiment, when the ball ring is located exactly in the middle of the two outer raceways, the elastic element undergoes elastic deformation due to the compression of the inner raceway and the outer raceway.

[0018] In at least one embodiment, the stiffness coefficient of the elastic element changes during the elastic deformation process of the elastic element.

[0019] In at least one embodiment, the portion of the elastic element located between the inner raceway and the outer raceway is at least partially wavy.

[0020] In at least one embodiment, the elastic element is generally U-shaped, and the elastic element includes a connecting portion and two wave springs connected to two ends of the connecting portion.

[0021] The two wave springs are respectively inserted between the inner raceway and the outer raceway of one of the raceway pairs.

[0022] In at least one embodiment, the inner raceway is partially recessed on the side facing the ball ring mounting portion to form a concave surface, the concave surface being a part of a sphere, and the concave surface contacting the ball ring.

[0023] In at least one embodiment, the side of the outer raceway facing away from the ball ring mounting portion is partially recessed to form a curved surface, which contacts the cage assembly.

[0024] In at least one embodiment, the cage assembly includes a frame and a ball.

[0025] The frame includes a ring-shaped portion and three arms connected to the ring-shaped portion. The arms extend axially along the ring-shaped portion, and several notched ball pockets are formed on both sides of the arms in the circumferential direction.

[0026] The ball is contained within the ball pocket, and the ball can roll relative to the ball pocket within the ball pocket.

[0027] Each of the arms is inserted between the two raceway assemblies, and the ball abuts against the raceway assembly.

[0028] In at least one embodiment, each arm has an arm recess formed radially inward at the midpoint between the two rows of ball pockets in the circumferential direction.

[0029] In at least one embodiment, the second connecting member includes a tubular sliding sleeve, the first end of which is connected to the first connecting member in the axial direction.

[0030] The inner cavity of the sleeve includes three radially inwardly projecting ribs spaced apart in the circumferential direction near the first end in the axial direction. The ribs extend along the axial direction, thereby forming a groove between every two adjacent ribs.

[0031] The arm is aligned with the ridge in the circumferential direction, the ball abuts against the ridge, and each of the raceway assemblies is received within one of the grooves.

[0032] In at least one embodiment, each of the protrusions forms a concave arc surface on each side of the circumferential direction, and the ball abuts against the arc surface.

[0033] In at least one embodiment, the end of the arm furthest from the annular portion is formed with a hook portion that protrudes radially outward from the annular portion.

[0034] The hook engages with the protrusion to prevent the cage assembly from dislodging from the first end.

[0035] In at least one embodiment, the outer periphery of the annular portion includes a plurality of annular protrusions protruding radially outward, the annular protrusions abutting against the end face of the sliding sleeve at the first end to limit the cage assembly in the axial direction.

[0036] In at least one embodiment, the inner cavity of the sliding sleeve does not have the protrusion at the second end, which is axially away from the first end.

[0037] The second connecting member further includes a vibration damping component, which is mounted on the second end in a manner that prevents relative rotation with the sliding sleeve, and the vibration damping component extends at least partially into the inner cavity of the sliding sleeve.

[0038] The shaft abuts against the vibration damping assembly, and the axial end of the shaft near the vibration damping assembly forms a spherical surface. The portion of the vibration damping assembly that contacts the shaft is also spherical.

[0039] In at least one embodiment, the vibration damping assembly includes an adapter, a cup shell, and a buffer.

[0040] The adapter and the sliding sleeve are connected in a way that prevents them from rotating relative to each other.

[0041] The cup shell is connected to the adapter, and the buffer is disposed between the cup shell and the adapter.

[0042] The portion of the shaft that contacts the vibration damping assembly is located in the cup shell, and the portion of the cup shell that contacts the shaft forms a concave spherical recess.

[0043] In at least one embodiment, a spline hole is formed on the inner periphery of the adapter.

[0044] In at least one embodiment, the adapter is embedded in the inner cavity of the sliding sleeve.

[0045] The adapter has a boss protruding from the middle of its end face facing the shaft, and the cup shell is axially movable relative to the boss and fitted onto the boss.

[0046] In at least one embodiment, when the buffer is not compressed, there is a gap between the cup shell and the end face of the adapter facing the shaft.

[0047] According to a second aspect of the invention, a steering mechanism is provided, comprising a motor, a coupling, and a worm gear assembly, wherein the coupling is a three-ball-pin coupling according to the invention.

[0048] The first connecting member of the three-ball pin coupling is connected to the worm in the worm gear assembly in a manner that prevents relative rotation, and the second connecting member of the three-ball pin coupling is connected to the output shaft of the motor in a manner that prevents relative rotation.

[0049] The three-ball pin coupling according to the present invention can reduce vibration during transmission and effectively transmit torque even when there is axial misalignment between transmission components.

[0050] The steering mechanism according to the present invention is less prone to backlash and vibration during operation. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of a three-ball pin coupling according to an embodiment of the present invention.

[0052] Figure 2 yes Figure 1 A cross-sectional view along the axial direction.

[0053] Figure 3 yes Figure 2 A schematic diagram of the structure of shaft 11.

[0054] Figure 4 yes Figure 2 A schematic diagram of the structure of the three-pin joint 12 and the ball ring 13.

[0055] Figure 5 yes Figure 1 A schematic diagram of the structure of the raceway assembly 20.

[0056] Figure 6 yes Figure 5 A schematic diagram of the raceway frame 21 of the raceway assembly 20.

[0057] Figure 7 yes Figure 5 A schematic diagram of the inner raceway 22 of the raceway assembly 20.

[0058] Figure 8 yes Figure 5 A schematic diagram of the outer raceway 23 of the raceway assembly 20.

[0059] Figure 9 yes Figure 5 A schematic diagram of the elastic element 24 of the raceway assembly 20 shown.

[0060] Figure 10 yes Figure 1 A schematic diagram of the cage assembly 30.

[0061] Figure 11 yes Figure 11 A schematic diagram of the structure of the frame 31.

[0062] Figure 12 yes Figure 1 A schematic diagram of the structure of the sliding sleeve 40.

[0063] Figure 13 yes Figure 1 A schematic diagram of the vibration damping component 50.

[0064] Figure 14 yes Figure 13 A schematic diagram of the structure of the adapter 51.

[0065] Figure 15 yes Figure 2 A cross-sectional schematic diagram of the cup shell 52 and the buffer component 53.

[0066] Explanation of reference numerals in the attached figures:

[0067] M is the first connecting component; N is the second connecting component;

[0068] 10 Three-pin assembly; 11 Shaft; 11s Spherical surface; 11h Pin hole; 12 Three-pin joint; 12n Neck; 13 Ball ring;

[0069] 20 Raceway assembly; 20s Ball ring mounting part; 21 Raceway frame; 211 Side frame; 211a Embossed edge; 212 Connecting rod; 22 Inner raceway; 22s Ball concave surface; 23 Outer raceway; 23a Curved surface; 24 Elastic element; 241 Wave spring; 242 Connecting part;

[0070] 30 Cage assembly; 31 Cage body; 311 Annular portion; 311a Annular protrusion; 312 Arm; 312a Arm recess; 31b Ball pocket; 31h Hook; 32 Ball;

[0071] 40 Sliding sleeve; 401 First end; 402 Second end; 41 Protrusion; 41a Arc surface; 42 Groove;

[0072] 50 Vibration damping component; 51 Adapter; 511 Main body; 512 Boss; 51h Spline hole; 52 Cup shell; 52s Ball recess; 53 Buffer; 53s Ball recess;

[0073] A represents the axial direction; R represents the radial direction; G represents the clearance. Detailed Implementation

[0074] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement the present invention, and are not intended to exhaustively describe all possible ways of the invention, nor to limit the scope of the invention.

[0075] Unless otherwise specified, refer to Figure 1 and Figure 2 A represents the axial direction of the three-ball pin coupling, which is consistent with the axial direction of the sliding sleeve 40; R represents the radial direction of the three-ball pin coupling, which is consistent with the radial direction of the sliding sleeve 40.

[0076] Reference Figures 1 to 15 This invention relates to a three-ball-pin coupling (hereinafter also referred to as the coupling) and a steering mechanism including the coupling.

[0077] The steering mechanism according to the invention includes a motor, a three-ball-pin coupling, and a worm gear assembly, wherein the three-ball-pin coupling connects the output shaft of the motor and the worm in the worm gear assembly, so that the torque of the output shaft can be transmitted to the worm.

[0078] Reference Figure 1 and Figure 2 The three-ball-pin coupling according to the present invention includes a first coupling M and a second coupling N that are torsionally connected (not rotatably connected), wherein the first coupling M is used to connect to the worm gear and the second coupling N is used to connect to the output shaft of the motor.

[0079] First, refer to Figures 1 to 11 A first connecting member M according to an embodiment of the present invention is described.

[0080] The first connecting member M includes a three-pin assembly 10, a raceway assembly 20, and a cage assembly 30.

[0081] The three-pin assembly 10 includes a shaft 11, three pin joints 12, and a ball ring 13.

[0082] Shaft 11 is used for a torsionally anti-torsional connection with the worm gear. (See reference...) Figure 3 In this embodiment, the first end of shaft 11 ( Figure 3 The left end of the shaft 11 has a hole 11h that passes through the shaft 11 radially R. The hole 11h is used to engage with a pin. For example, one end of the worm has an axially extending inner hole and a radially extending pin hole intersecting the inner hole. The first end of the shaft 11 can be inserted into the inner hole, and a pin is used to pass through the pin hole and the hole 11h, thereby connecting the shaft 11 and the worm together in a torsion-resistant manner.

[0083] The second end of shaft 11 ( Figure 3 The right end of the structure has a spherical surface 11s, which is used to cooperate with the vibration damping assembly 50, which will be described in detail below, to achieve the function of universal adjustment.

[0084] Reference Figure 2 and Figure 4The three-pin joint 12 includes a central ring 12r and three radially extending necks 12n connected to the outer periphery of the ring 12r. Preferably, the three necks 12n are evenly spaced circumferentially from the ring 12r. Each neck 12n is fitted with a ball ring 13 on its outer periphery, the outer circumferential surface of which is part of a sphere. It should be understood that rolling elements may be provided between the necks 12n and the ball rings 13. The three-pin joint 12 is fitted onto the outer periphery of the shaft 11 and is torsionally connected to the shaft 11 by, for example, an interference fit.

[0085] Reference Figure 1 Each ball ring 13 is connected to a raceway assembly 20, and the three raceway assemblies 20 are limited in the axial A and circumferential directions of the shaft 11 by the cage assembly 30.

[0086] Reference Figures 5 to 9 Introducing raceway assembly 20.

[0087] In this embodiment, the raceway assembly 20 includes a raceway frame 21, an inner raceway 22, an outer raceway 23, and an elastic member 24.

[0088] Reference Figure 6 The raceway frame 21 includes two generally rectangular side frames 211 and a connecting rod 212 connecting the two side frames 211. A through hole extending through the connecting rod 212 is located in the middle of each side frame 211. Pockets 211a are protruding from the opposing inner surfaces of the two side frames 211. Specifically, four pockets 211a are formed on one side frame 211, each pocket 211a being generally C-shaped. The main body of the pocket 211a located in the middle of the C-shape extends along the long side of the side frame 211, and these four pockets 211a generally occupy the four corners of the side frame 211. The C-shaped openings of two opposing pockets 211a on the two long sides of the side frame 211 face each other, thereby defining a slot 211b between the two pockets 211a. Each side frame 211 has two slots 211b located on both sides of the connecting rod 212, the slots 211b for mounting the inner raceway 22 and the outer raceway 23. The slots 211b of the two side frames 211 on the same side of the connecting rod 212 are opposite each other for mounting a raceway pair.

[0089] Simultaneously refer to Figure 5 An inner raceway 22 and an outer raceway 23 form a raceway pair. A raceway assembly 20 includes two raceway pairs. The inner raceway 22 is disposed closer to the connecting rod 212 on the inner side of the outer raceway 23. Both ends of the inner raceway 22 and the outer raceway 23 extend into two pockets 211b and are connected to the raceway frame 21. The space between the two inner raceways 22 forms a ball ring mounting portion 20s, in which a ball ring 13 can be fitted.

[0090] Simultaneously refer to Figure 7The opposing surfaces of the two inner raceways 22 are partially concave to form concave surfaces 22s. Preferably, the concave surfaces 22s are part of a sphere. When the ball ring 13 is inserted into the ball ring mounting portion 20s, the ball ring 13 is clamped by the two concave surfaces 22s. Due to the mating of the spherical surface of the ball ring 13 and the spherical surface of the concave surface 22s, the ball ring 13 can swing in all directions within a small range relative to the concave surface 22s, but the ball ring 13 will not disengage from the raceway assembly 20. Since the position of the ball ring 13 relative to the three-pin joint 12 (or shaft 11) in the axial direction A and circumferential direction are determined, the position of the raceway assembly 20 relative to the shaft 11 in the axial direction A and circumferential direction can be determined by the mating method of the ball ring 13 and the two concave surfaces 22s of the raceway assembly 20.

[0091] Reference Figure 5 and Figure 9 The elastic element 24 is generally U-shaped and includes a connecting portion 242 and two wave springs 241 connected to the two ends of the connecting portion 242. The two wave springs 241 are respectively inserted between the inner raceway 22 and the outer raceway 23 of a raceway pair. The connecting portion 242 passes through a hole in the middle of the side frame 211, and preferably, the connecting portion 242 is completely received within the hole in the middle of the side frame 211.

[0092] The two sides of the wave spring 241 abut against the inner raceway 22 and the outer raceway 23 respectively. Preferably, in the initial state (when the coupling has not yet been installed with the motor shaft and worm gear, and the ball ring 13 is located in the middle of the two outer raceways 23), the wave spring 241 is slightly deformed by the slight compression of the inner raceway 22 and the outer raceway 23. At this time, the elastic force generated by the wave spring 241 presses the inner raceway 22 and the outer raceway 23 against the contour edge of the pocket 211b. That is, in the extension direction of the long side of the side frame 211, the inner raceway 22 and the outer raceway 23 abut against the pocket edge 211a respectively to fill the pocket 211b.

[0093] During the operation of the steering mechanism, the ball ring 13 will press one of the inner raceways 22 in a certain direction (this state will be further described below), causing the wave spring 241 to be compressed and deformed.

[0094] The wave spring 241 is wavy and is a non-linear spring, meaning that its stiffness coefficient (also known as elastic coefficient) changes during the compression and deformation process. Therefore, the force exerted by the wave spring 241 on the inner raceway 22 and outer raceway 23 varies with the degree of deformation, which is beneficial for maintaining a certain transmission stiffness.

[0095] Reference Figure 5 and Figure 8The middle part of the outer raceway 23 facing away from the ball ring mounting part 20s is recessed to form a curved surface 23a, which contacts the ball 32 of the cage assembly 30, which will be further described below.

[0096] Next, refer to Figure 1 , Figure 10 and Figure 11 The specific structure of the cage assembly 30 and its limiting function on the raceway assembly 20 are described.

[0097] The cage assembly 30 includes a cage body 31 and balls 32. The cage body 31 includes an annular portion 311 and three arms 312 connected to the annular portion 311. The three arms 312 are evenly spaced circumferentially around the annular portion 311 and extend axially along the annular portion 311. The arms 312 mate with the raceway assembly 20 on one hand and with the protrusion 41 of the sleeve 40 located in the second connecting member N on the other hand (described further below).

[0098] Reference Figure 11 Each arm 312 has two rows of notches on both sides of the annular portion 311 in the circumferential direction. Each row of notches includes several (3 in the figure) ball pockets 31b in the shape of a large semicircle (the semicircle corresponding to the dominant arc).

[0099] Reference Figure 10 Each ball pocket 31b contains a ball 32, preferably a steel ball. The ball 32 is floatably contained within the ball pocket 31b, that is, the ball 32 can roll within the ball pocket 31b, but the ball 32 does not roll out of the ball pocket 31b.

[0100] Back Figure 11 Each arm 312 has a radially inwardly recessed arm recess 312a located at the center between the two rows of ball pockets 31b in the circumferential direction. The end of the arm 312 away from the annular portion 311 has a radially outwardly protruding hook portion 31h. Preferably, the outer periphery of the annular portion 311 also has three radially outwardly protruding annular protrusions 311a, located circumferentially between two adjacent arms 312. The arm recess 312a is used to mate with the protrusion 41 of the sleeve 40 of the second connector N, which will be further described below, to define the position between the first connector M and the second connector N in the circumferential direction; the hook portion 31h is used to hook the protrusion 41 to define the position between the first connector M and the second connector N in the axial direction A; the annular protrusion 311a is used to abut against the end face of the first end 401 of the sleeve 40 (which will be further described below) in the axial direction A to define the position between the first connector M and the second connector N in the axial direction A.

[0101] Back Figure 1For the first connecting member M, a raceway assembly 20 is accommodated between two adjacent arms 312, and the ball 32 abuts against the curved surface 23a of the outer raceway 23 of the raceway assembly 20. Furthermore, in the axial direction A, the raceway assembly 20 (specifically, the raceway frame 21 of the raceway assembly 20) abuts against the frame 31 of the cage assembly 30, so that the raceway assembly 20 will not... Figure 1 The left side of the body prolapsed.

[0102] By now, the reader can understand how the three-pin assembly 10, the raceway assembly 20, and the cage assembly 30 are connected to form a whole. The first connecting member M of this whole can transmit torque in the circumferential direction. That is, the cage assembly 30 can transmit torque to the shaft 11 through the raceway assembly 20, the ball ring 13, and the three-pin joint 12. Furthermore, the components of the first connecting member M can absorb vibrations during the transmission of torque between them (which will be further explained below).

[0103] Next, refer to Figure 1 , Figure 2 , Figures 12 to 15 The second connecting member N according to the present invention, and the connection relationship between the second connecting member N and the first connecting member M are described.

[0104] The second connecting member N includes a torsionally connected sliding sleeve 40 and a vibration damping assembly 50.

[0105] Reference Figure 1 ( Figure 1 The double-dotted line in the image indicates the sliding sleeve 40). Figure 2 and Figure 12 The sliding sleeve 40 is roughly cylindrical. The first end 401 of the sliding sleeve 40 along the axial direction A... Figure 12 The left end of the sliding sleeve 40 is connected to the first connecting member M, and the second end 402 of the sliding sleeve 40 in the axial direction A is connected to the first connecting member M. Figure 12 The right end of the middle section is connected to the vibration damping component 50.

[0106] The inner cavity of the sleeve 40 has three radially inward protruding ribs 41 that are evenly distributed in the circumferential direction at the first end 401. The ribs 41 extend along the axial direction A, thereby forming a groove 42 between every two adjacent ribs 41.

[0107] Each protrusion 41 has a recessed arc surface 41a on each side in the circumferential direction. Each arc surface 41a is abutted against by a row of balls 32 mounted on an arm 312. In other words, each protrusion 41 matches a corresponding arm 312. The length of the protrusion 41 in the axial direction A is approximately equal to the length of the arm 312.

[0108] Combination Figure 1 and Figure 11The protruding portion of the rib 41 is positioned opposite to the recess 312a of the arm, and the ball 32 abuts against the arc surface 41a. The arm 312 has a certain elasticity in the radial direction R. When the first connecting member M is inserted into the slide sleeve 40 from the first end 401, the hook 31h is squeezed by the rib 41 and undergoes elastic deformation in the radial direction. When the first connecting member M continues to extend into the slide sleeve 40 until the annular protrusion 311a abuts against the end face of the slide sleeve 40 located at the first end 401, the first connecting member M is installed in place. At this time, the hook 31h just exceeds the area covered by the rib 41 in the axial direction A. The hook 31h pops out radially outward, and the arm 312 returns to its original shape. The hook 31h hooks the axial end face of the rib 41 away from the first end 401, so that the annular protrusion 311a and the hook 31h respectively define the relative position of the retainer assembly 30 and the slide sleeve 40 at both ends in the axial direction A.

[0109] At this time, the raceway assembly 20 is accommodated in the groove 42. The raceway assembly 20 is positioned in the circumferential direction by the ball 32, and the ball 32 is positioned in the circumferential direction by the arc surface 41a, thereby realizing the mutual positioning of the first connecting member M and the second connecting member N in the circumferential direction.

[0110] Back Figure 12 The inner cavity of the sliding sleeve 40 does not have a protrusion 41 near the second end 402, thus forming a smooth cylindrical surface.

[0111] Preferably, for machining the inner cavity of the sleeve 40 with the above-described structure, for example, three protrusions penetrating the inner cavity of the sleeve 40 in the axial direction A can be machined using a rotary forging method. Then, near the second end 402, part of the protrusions is removed by machining to form... Figure 12 The convex strip 41 shown.

[0112] Reference Figure 1 and Figure 2 The second end 402 of the sliding sleeve 40 is used to mount the vibration damping assembly 50. The vibration damping assembly 50 includes an adapter 51, a cup shell 52, and a buffer 53. The adapter 51 is torsionally connected to the sliding sleeve 40.

[0113] Combination Figure 13 and Figure 14 The adapter 51 includes a main body 511 and a boss 512. The main body 511 is disc-shaped, and a cylindrical boss 512 protrudes from the middle of the end face of the main body 511 facing the first end 401. The boss 512 is used to mount the cup shell 52. A spline hole 51h is also provided in the middle of the adapter 51. The spline hole 51h is used to connect with the output shaft of the motor of the steering mechanism. For example, the output shaft is provided with a male spline that matches the spline hole 51h.

[0114] Preferably, the adapter 51 is made of engineering plastic, which has a suitable deformation capacity. The adapter 51 is embedded in the inner cavity of the sliding sleeve 40, and the anti-torsional connection between the adapter 51 and the sliding sleeve 40 is achieved through the interference fit between the main body 511 and the sliding sleeve 40; when the spline hole 51h is engaged with the male spline, the spline hole 51h is slightly opened by the male spline, thereby achieving a clearance-free fit between the adapter 51 and the male spline.

[0115] Reference Figure 2 and Figure 15 The cup shell 52 is cup-shaped and is formed, for example, by stamping. The cup shell 52 is fitted onto the boss 512 of the adapter 51, and the cup shell 52 can move slightly relative to the boss 512 in the axial direction A (this slight movement will be easier for the reader to understand when the clearance G is described below). In the axial direction A, a buffer 53 is provided in the inner cavity of the cup shell 52, or between the cup shell 52 and the adapter 51. The buffer 53 is made of rubber, for example, and the rubber buffer 53 is formed into the inner cavity of the cup shell 52, for example, by vulcanization.

[0116] When the cup shell 52 is fitted onto the boss 512, in the initial state, the boss 512 abuts against the buffer member 53, but the cup shell 52 does not abut against the main body 511. That is, there is a gap G between the cup shell 52 and the main body 511 in the axial direction A (see...). Figure 2 Because the buffer 53 can elastically deform in the axial direction A, the shaft 11 can be displaced in the axial direction A relative to the adapter 51 within a small range.

[0117] A spherical recess 52s is formed recessed in the middle of the end face of the cup shell 52 facing the shaft 11 along the axial direction A. Correspondingly, a spherical recess 53s is also formed at the corresponding position of the elastic member closely attached to the cup shell 52. The spherical recess 52s is used to abut against the spherical surface 11s of the shaft 11. Preferably, the radius of the sphere corresponding to the spherical surface 11s is slightly smaller than the radius of the sphere corresponding to the spherical recess 52s.

[0118] The spherical surface 11s abuts against the spherical recess 52s, so that when the shaft 11 is deviated relative to the axial direction A, the spherical recess 52s can still effectively center and position the shaft 11.

[0119] Thus, when the first connecting member M and the second connecting member N are connected, in the axial direction A, the shaft 11, which is one connecting end of the coupling, is abutted against the cup shell 52 on one side and is limited relative to the second connecting member N, and on the other side is limited by the raceway assembly 20 connected to the shaft 11 (the raceway assembly 20 is limited relative to the frame 31 in the axial direction A) and is limited relative to the second connecting member N.

[0120] Combined again Figure 1 and Figure 2This describes the self-aligning and vibration-damping capabilities of the coupling according to the present invention. When the steering mechanism reverses direction, if the axial clearance of the self-aligning bearing on one side of the worm is too small, the meshing of the worm gear and worm will switch from static friction to dynamic friction, causing a sharp increase or decrease in frictional torque. One way to avoid or mitigate this sharp increase or decrease in frictional torque is to increase the axial clearance of the self-aligning bearing. This results in axial acceleration between the bearing components, and the vibration energy caused by this axial acceleration can be absorbed by the coupling according to the present invention.

[0121] For example, when the axial acceleration generated by the self-aligning bearing is transmitted to the shaft 11, the impact of the shaft 11 on the cup shell 52 will be absorbed by the buffer 53 because the shaft 11 abuts against the vibration damping component 50.

[0122] Furthermore, the gap between the teeth of the worm wheel, which wears under high torque, will increase, causing the worm meshing with the worm wheel to vibrate and deviate in each direction. This vibration can be absorbed by the coupling according to the invention, and this deviation can be adjusted by the coupling according to the invention.

[0123] For example, when the shaft 11 is offset relative to the axis of the sleeve 40 (this offset may be accompanied by axial displacement of the shaft 11 relative to the sleeve 40 and / or circumferential deflection of the shaft 11 relative to the sleeve 40), the ball ring 13 will compress the inner raceway 22, causing a change in the distance between the inner raceway 22 and the outer raceway 23. The vibration energy generated by this change in distance can be absorbed by the elastic element 24. When the raceway assembly 20 is offset relative to the cage assembly 30, the six rows of balls 32 on the cage assembly 30 roll relative to the curved surfaces 23a of the six outer raceways located in the three raceway assemblies 20, which does not easily generate steep rises and falls in friction.

[0124] Finally, an assembly method for the three-ball pin coupling according to the present invention is introduced:

[0125] The inner raceway 22, outer raceway 23, and elastic element 24 are mounted onto the raceway frame 21 to form the raceway assembly 20. Then, the three raceway assemblies 20 are mounted onto the three-pin assembly 10 to form the three-pin universal swing module.

[0126] The cup shell 52 with the buffer 53 is connected to the adapter 51 to form the vibration damping assembly 50.

[0127] The ball 32 is installed into the ball pocket 31b of the frame 31 to form the cage assembly 30.

[0128] The vibration damping component 50 is assembled with the sliding sleeve 40 with an interference fit. Then, the retainer assembly 30 drives the three-pin universal swing module to be installed into the sliding sleeve 40 along the axial direction A. When the hook 31h and the ring protrusion 311a of the retainer assembly 30 are in place with the sliding sleeve 40 and the shaft 11 abuts against the cup shell 52, the assembly is completed.

[0129] It should be understood that the execution order of the various sub-steps of the above assembly can be adjusted.

[0130] The following is a brief description of some of the beneficial effects of the above-described embodiments of the present invention.

[0131] (i) According to the present invention, the first connecting member M of the three-ball pin coupling uses a three-pin assembly 10, in which the ball ring 13 of the three-pin assembly 10 forms a spherical fit with the inner raceway 22 of the raceway assembly 20, and the raceway assembly 20 fits with the sliding sleeve 40 of the second connecting member N, thereby realizing the omnidirectional swing of the first connecting member M relative to the second connecting member N. Even when the first connecting member M and the second connecting member N are offset by a large angle (e.g., + / - 1.5°), torque can still be transmitted between the first connecting member M and the second connecting member N. In other words, even under high loads, such as when the plastic worm gear experiences significant wear or the worm axis is significantly offset, the worm's offset angle can be dynamically compensated.

[0132] (ii) The raceway assembly 20 has a non-linear wave spring 241, on both sides of which the inner raceway 22 and the outer raceway 23 are flexibly fixed. The three raceway assemblies 20 are arranged around the three-pin assembly 10, enabling backlash-free transmission between the first connecting member M and the second connecting member N in the circumferential direction. The elastic element 24 can compensate for tolerances, ensuring transmission stiffness while reducing the tolerance requirements for the production of related parts, improving production robustness, and meeting the backlash-free torque transmission requirements between the transmission components, thereby avoiding reversing backlash and vibration impact.

[0133] (iii) The cage assembly 30 has a floating ball 32, which forms a straight raceway pair with the sliding sleeve 40 and the outer raceway 23, eliminating the problem of steep increases and decreases in friction during transmission. Moreover, the ball 32 and the cage body 31 are easy to process and install. The ball 32 can be installed with the cage body 31 first, and then installed into the inner cavity of the sliding sleeve 40 together with the cage body 31, which is easy to achieve in terms of process.

[0134] (iv) The second connecting member N of the three-ball pin coupling according to the present invention includes a vibration damping component 50, which makes the transmission component less prone to axial vibration and reduces the control requirements for the axial clearance of the self-aligning bearing of the steering mechanism.

[0135] (v) The steering mechanism according to the present invention is less prone to back-and-forth reversing and continuous starting and stopping processes, and is less prone to system vibration due to friction fluctuations.

[0136] It should be understood that the above embodiments are merely exemplary and not intended to limit the present invention. Those skilled in the art can make various modifications and changes to the above embodiments under the guidance of the present invention without departing from the scope of the invention. For example,

[0137] (i) The adapter 51 may not be an insert embedded in the sleeve 40, but may be connected to the sleeve 40 by means of, for example, screw connection, threaded connection or welding.

[0138] (ii) The three-pin joint 12 can also be integrally formed with the shaft 11.

[0139] (iii) The roller frame 21 can be other frame shapes, and the present invention does not limit this.

[0140] (iv) The two wave springs 241 of the same raceway assembly 20 may form two independent elastic elements without being connected by the connecting part 242.

Claims

1. A three-ball-pin coupling, comprising a first connecting member (M) and a second connecting member (N) that are not rotatably connected relative to each other, wherein, The first connecting member (M) includes a three-pin assembly (10), a raceway assembly (20), and a cage assembly (30). The three-pin assembly (10) includes a shaft (11) and three ball rings (13) spaced apart circumferentially around the shaft (11). There are three raceway assemblies (20), each ball ring (13) connected to one raceway assembly (20). The cage assembly (30) defines the position of the raceway assembly (20) in the circumferential direction. The raceway assembly (20) provides an elastic force between the ball ring (13) and the cage assembly (30), and when the ball ring (13) is displaced relative to the cage assembly (30) in the circumferential direction, the raceway assembly (20) remains in contact with the cage assembly (30) on both sides in the circumferential direction. The cage assembly (30) includes a frame (31) and a ball (32). The frame (31) includes an annular portion (311) and three arms (312) connected to the annular portion (311). The arms (312) extend along the axial direction (A) of the annular portion (311), and several notched ball pockets (31b) are formed on both sides of the arms (312) in the circumferential direction. The ball (32) is housed within the ball pocket (31b), and the ball (32) is capable of rolling relative to the ball pocket (31b) within the ball pocket (31b). Each of the arms (312) is inserted between the two raceway assemblies (20), and the ball (32) abuts against the raceway assembly (20).

2. The three-ball pin coupling according to claim 1, characterized in that, The raceway assembly (20) includes a raceway frame (21), an inner raceway (22), an outer raceway (23), and an elastic element (24). Each of the raceway frames (21) is equipped with two inner raceways (22) and two outer raceways (23). The two inner raceways (22) are spaced apart to form a ball ring mounting portion (20s) between the two inner raceways (22). Each inner raceway (22) has an outer raceway (23) mounted on the side away from the ball ring mounting portion (20s). An inner raceway (22) and an outer raceway (23) on the same side of the ball ring mounting portion (20s) form a raceway pair. The elastic element (24) is at least partially disposed between the inner raceway (22) and the outer raceway (23), and the elastic element (24) abuts against both the inner raceway (22) and the outer raceway (23) of each raceway pair.

3. The three-ball pin coupling according to claim 2, characterized in that, When the ball ring (13) is located in the middle of the two outer raceways (23), the elastic element (24) is compressed by the inner raceway (22) and the outer raceway (23) and undergoes elastic deformation.

4. The three-ball pin coupling according to claim 2, characterized in that, During the elastic deformation of the elastic element (24), the stiffness coefficient of the elastic element (24) changes.

5. The three-ball pin coupling according to claim 4, characterized in that, The portion of the elastic element (24) located between the inner raceway (22) and the outer raceway (23) is at least partially wavy.

6. The three-ball pin coupling according to claim 5, characterized in that, The elastic element (24) is U-shaped in general. The elastic element (24) includes a connecting part (242) and two wave springs (241) connected to the two ends of the connecting part (242). The two wave springs (241) are respectively inserted between the inner raceway (22) and the outer raceway (23) of one raceway pair.

7. The three-ball pin coupling according to claim 2, characterized in that, The inner raceway (22) is partially recessed on one side facing the ball ring mounting portion (20s) to form a concave spherical surface (22s), which is part of a spherical surface and is in contact with the ball ring (13).

8. The three-ball pin coupling according to claim 2, characterized in that, The outer raceway (23) is partially recessed on the side opposite to the ball ring mounting portion (20s) to form a curved surface (23a), which contacts the cage assembly (30).

9. The three-ball pin coupling according to claim 1, characterized in that, Each of the arms (312) has an arm recess (312a) formed radially inward at the middle of the two rows of ball pockets (31b) in the circumferential direction.

10. The three-ball pin coupling according to claim 1, characterized in that, The second connecting member (N) includes a tubular sliding sleeve (40), the first end (401) of which is connected to the first connecting member (M) in the axial direction (A). The inner cavity of the sleeve (40) includes three radially inwardly projecting ribs (41) spaced apart in the circumferential direction near the first end (401) along the axial direction (A), the ribs (41) extending along the axial direction (A) to form a groove (42) between every two adjacent ribs (41). The arm (312) is aligned with the rib (41) in the circumferential direction, the ball (32) abuts against the rib (41), and each of the raceway assemblies (20) is received in one of the grooves (42).

11. The three-ball pin coupling according to claim 10, characterized in that, Each of the protrusions (41) has a recessed arc surface (41a) on each side in the circumferential direction, and the ball (32) abuts against the arc surface (41a).

12. The three-ball pin coupling according to claim 10, characterized in that, The end of the arm (312) away from the annular portion (311) is formed with a hook portion (31h) that protrudes radially outward from the annular portion (311). The hook (31h) engages with the protrusion (41) to prevent the cage assembly (30) from dislodging from the first end (401).

13. The three-ball pin coupling according to claim 10, characterized in that, The outer periphery of the annular portion (311) includes a plurality of annular protrusions (311a) that protrude radially outward, the annular protrusions (311a) abutting against the end face of the sliding sleeve (40) located at the first end (401) to limit the cage assembly (30) in the axial direction (A).

14. The three-ball pin coupling according to claim 10, characterized in that, The inner cavity of the sleeve (40) does not have the protrusion (41) at the second end (402) away from the first end (401) in the axial direction (A). The second connecting member (N) further includes a vibration damping assembly (50), which is mounted on the second end (402) in a manner that prevents relative rotation with the sliding sleeve (40). The vibration damping assembly (50) extends at least partially into the inner cavity of the sliding sleeve (40). The shaft (11) abuts against the vibration damping assembly (50), and the axial end of the shaft (11) near the vibration damping assembly (50) forms a spherical surface (11s). The portion of the vibration damping assembly (50) that contacts the shaft (11) is spherical.

15. The three-ball pin coupling according to claim 14, characterized in that, The vibration damping assembly (50) includes an adapter (51), a cup shell (52), and a buffer (53). The adapter (51) and the sliding sleeve (40) are connected in a way that prevents them from rotating relative to each other. The cup shell (52) is connected to the adapter (51), and the buffer (53) is disposed between the cup shell (52) and the adapter (51). The portion of the shaft (11) that contacts the vibration damping assembly (50) is located in the cup shell (52), and the portion of the cup shell (52) that contacts the shaft (11) forms a concave spherical recess (52s).

16. The three-ball pin coupling according to claim 15, characterized in that, The inner periphery of the adapter (51) forms a spline hole (51h).

17. The three-ball pin coupling according to claim 15, characterized in that, The adapter (51) is embedded in the inner cavity of the sliding sleeve (40). The adapter (51) has a boss (512) protruding from the middle of its end face facing the shaft (11), and the cup shell (52) is axially movable relative to the boss (512) and fitted onto the boss (512).

18. The three-ball pin coupling according to claim 17, characterized in that, When the buffer (53) is not compressed, there is a gap (G) between the cup shell (52) and the end face of the adapter (51) facing the shaft (11).

19. A steering mechanism comprising a motor, a coupling, and a worm gear assembly, characterized in that, The coupling is a three-ball pin coupling according to any one of claims 1 to 18. The first connecting member (M) of the three-ball pin coupling is connected to the worm in the worm gear assembly in a way that prevents relative rotation, and the second connecting member (N) of the three-ball pin coupling is connected to the output shaft of the motor in a way that prevents relative rotation.

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