Angle adjusting apparatus for small-tooth-difference planetary gear system

Abstract

Provided is an angle adjusting apparatus for a small-tooth-difference planetary gear system. The angle adjusting apparatus comprises a wedge (5), a driving cam (6), and an elastic member (9). The wedge (5) is composed of two wedge-shaped sections (5.1, 5.2). The driving cam (6) is provided with a driving section (6.2). The driving section (6.2) comprises an arc-shaped block (6a) and two protruding blocks (6b, 6c) spaced apart from the arc-shaped block (6a). The arc-shaped block (6a) is inserted into a clearance between tail portions of the two wedge-shaped sections (5.1, 5.2). The elastic member (9) is composed of two split elastic elements. The two elastic elements are respectively mounted on the two wedge-shaped sections (5.1, 5.2) and are accommodated between the arc-shaped block (6a) and the protruding blocks (6b, 6c).

Description

An angle adjustment device for a planetary gear train with small tooth difference Technical Field

[0001] The present invention relates to a mechanism operating based on the principle of a small-tooth-difference planetary gear train, and more particularly to an angle adjustment device for a small-tooth-difference planetary gear train. Background Art

[0002] Currently, the angle adjustment devices (hereinafter referred to as recliners) used in automotive seats are generally designed using the transmission principle of a small-tooth-difference planetary gear train (which can also be called a "small-tooth-difference planetary system"). The eccentricity is achieved through eccentric wedges or eccentric rings, and the torque transmitted by the cam drives the movement of the gear pair. Existing mainstream products have the following common problems: 1) Due to the tolerance design of the recliner during manufacturing and installation, as well as the locking requirement when not adjusting, the design will inevitably produce idle travel, which will cause a knocking sound during startup and adjustment and switching. 2) Due to manufacturing and assembly errors of components, the mechanism will inevitably form backlash, which will cause irregular vibration during the adjustment process, that is, a sense of unevenness. Summary of the Invention

[0003] In order to solve the problems of noise and jitter in the above-mentioned prior art, the present invention provides an angle adjustment device for a planetary gear train with a small tooth difference.

[0004] According to the angle adjustment device of the planetary gear system with small tooth difference of the present invention, it includes a wedge block, a driving cam and an elastic member, wherein the wedge block is composed of, for example, two wedge segments with a mirror-symmetrical design, the driving cam has a driving segment with, for example, a mirror-symmetrical design, the driving segment includes an arc block and two protrusions spaced apart from the arc block, the arc block is inserted into the gap between the tails of the two wedge segments, and the elastic member is composed of two split elastic elements, the two elastic elements are respectively mounted on the two wedge segments and accommodated between the arc block and the protrusion.

[0005] Preferably, the end face of each protrusion facing the arc block is formed as a small end face, the end face of the arc block facing each protrusion is formed as a large end face, the end face of each elastic element facing the head of each wedge segment is formed as a front end face, and the end face of each elastic element facing the tail of each wedge segment is formed as a rear end face, the front end face cooperates with the small end face, and the rear end face cooperates with the large end face.

[0006] Preferably, the front end face contacts the small end face and is in a compressed state during operation, providing driving force for each wedge segment so that the heads of the two wedge segments remain spread apart to achieve the eccentricity required by the angle adjustment device.

[0007] Preferably, during operation, depending on the direction of rotation, the front end surface of the elastic element on only one side is selectively squeezed by the small end surface on that side due to the rotation of the driving cam, thereby providing driving force for the wedge-shaped segment on that side. That is, when the driving cam rotates clockwise, it can (further) squeeze the front end surface of the right elastic element, thereby driving the right wedge-shaped segment to move; while when it rotates counterclockwise, it can (further) squeeze the front end surface of the left elastic element, thereby driving the left wedge-shaped segment to move.

[0008] Preferably, the rear end surface contacts the large end surface to provide a buffer for the contact between the driving cam and the wedge block during startup or reversing.

[0009] Preferably, the rear end face of each elastic element extends beyond the tail of the wedge segment in the circumferential direction and is therefore closer to the large end face of the arc block, so that the rear end face of the elastic element can elastically abut against the large end face when moving toward the large end face.

[0010] Here, when the driving cam rotates clockwise, its left large end face rotates toward the rear end face of the left elastic element and elastically impacts this rear end face, which in some cases can continue to drive the left wedge segment to move. When the driving cam rotates counterclockwise, its right large end face rotates toward the rear end face of the right elastic element and elastically impacts this rear end face, which in some cases can continue to drive the right wedge segment to move. This can avoid the impact sound caused by rigid collision.

[0011] Preferably, when at rest, each elastic element maintains a certain pre-compression contact with the small end surface and / or no contact with the large end surface. This pre-compression contact between each elastic element and the small end surface during rest enables relative fixation between the drive cam, the wedge segment, and the elastic element, and enables instant actuation of the wedge segment upon commencement of operation. The lack of contact between the elastic element and the large end surface allows, when necessary, the drive cam to be rotated relative to the wedge segment to achieve concentricity when two drive cams are installed using a single synchronization rod.

[0012] Preferably, each wedge segment has a first groove and a second groove spaced apart by a boss, each elastic element has a first boss and a second boss spaced apart by a recess, the first boss is accommodated in the first groove, and the second boss is accommodated in the second groove.

[0013] Preferably, each projection fits into the first groove of each wedge-shaped segment.

[0014] Preferably, the angle adjustment device further comprises a cover plate mounted on the driving cam for limiting the elastic member.

[0015] Preferably, the angle adjustment device also includes a gear plate and a ring gear plate that can rotate relative to each other, an external gear is formed on the gear plate, and an internal gear ring is formed on the ring gear plate, and the external gear and the internal gear ring are meshed with each other to form a gear pair of a planetary gear train with a small tooth difference.

[0016] Preferably, the gear plate has a collar that is concentric with the external gear, and the wedge used to achieve the eccentricity of the planetary gear train gear pair with small tooth difference is supported on the collar by its curved inner surface, and carries the gear ring plate by its curved outer surface, thereby achieving the eccentric effect through the two inner and outer curved surfaces.

[0017] Preferably, the angle adjustment device further comprises a spring disposed between the two wedge-shaped segments for biasing them away from each other.

[0018] According to the angle adjustment device of the present invention, the drive mechanism of the gear pair of the small-tooth-difference planetary gear train includes an elastic member disposed in an eccentric region. During startup or reversing, the drive cam is accelerated by the external driving force within its idle stroke. The elastic member provides a pre-contact buffer, effectively reducing the impact noise during startup and reversing. During operation, the elastic member is in a compressed state, maintaining a certain range of spreading force between the two eccentric wedge segments (the spring is not compressed by the driving force and can maintain the spreading force) to absorb the mechanism's clearance, thereby improving anti-shake smoothness. Because the drive structure is a mirrored design for bidirectional operation, the same improved smoothness effect can be achieved when the mechanism operates clockwise or counterclockwise. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is an exploded view of a recliner according to a preferred embodiment of the present invention.

[0020] FIG2 is a schematic diagram of the assembly of the wedge block and the elastic member of FIG1 .

[0021] FIG3 is a schematic diagram of the assembly of the wedge block, the driving cam and the elastic member of FIG1 .

[0022] FIG4 is a schematic diagram of the assembled state of the wedge block, the driving cam, the elastic member and the cover plate of FIG1 .

[0023] FIG5 is a schematic structural diagram of FIG4 with the elastic member omitted. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0025] The angle adjustment device based on the small-tooth-difference planetary gear train according to the present invention is an electric or manual recliner, such as a seat back recliner, armrest recliner, or leg rest recliner. It should be understood that this angle adjustment device is primarily used in automotive seats, but can also be applied to furniture seats, specialty cabin seats, and the like.

[0026] As shown in Figure 1, a recliner according to a preferred embodiment of the present invention includes a hoop 1, a gear plate 2, and a ring gear plate 3, wherein the gear plate 2 and the ring gear plate 3 are configured to rotate relative to each other, and the hoop 1 is used to hold the gear plate 2 and the ring gear plate 3 together. In this embodiment, the hoop 1 is fixedly connected to the ring gear plate 3 for absorbing axial forces. It should be understood that the hoop 1 does not hinder the relative rotation of the gear plate 2 and the ring gear plate 3. The gear plate 2 can be mounted on the seat, while the ring gear plate 3 is mounted on the backrest, thereby adjusting the inclination angle of the backrest relative to the seat. Of course, the mounting positions of the gear plate 2 and the ring gear plate 3 can also be reversed, that is, the gear plate 2 can be mounted on the backrest, while the ring gear plate 3 is mounted on the seat.

[0027] The gear plate 2 and the ring gear plate 3 are connected to each other via a gear pair for adjustment and fixation. To form the gear pair, an externally toothed gear is formed on the gear plate 2, and an internally toothed ring gear is formed on the ring gear plate 3. The externally toothed gear and the internally toothed ring gear mesh with each other to form a gear pair for a small-tooth-difference planetary gear train. Specifically, the diameter of the externally toothed gear's tip circle is smaller than the diameter of the internally toothed ring gear's root circle by at least one tooth height. The externally toothed gear and the internally toothed ring gear differ in number by at least one tooth, allowing the internally toothed ring gear to roll on the externally toothed gear.

[0028] The gear plate 2 has a collar 2.1 that is concentric with the external gear. The recliner according to this embodiment also includes a wedge 5 for achieving eccentricity in the planetary gear train with a small tooth difference. The wedge 5 is supported on the collar 2.1 by its curved inner surface and supports the ring gear plate 3 by its curved outer surface, thereby achieving an eccentric effect through the inner and outer curved surfaces. Accordingly, the recliner according to this embodiment also includes a friction bearing 4, which is disposed between the curved outer surface of the wedge 5 and the center hole 3.1 of the ring gear plate 3. Furthermore, the recliner according to this embodiment also includes a drive cam 6, whose axially extending cylindrical section 6.1 is inserted into the collar 2.1 and has a central bore (not limited to a flower pattern) for receiving and matching a drive shaft, thereby actuating the drive cam 6 via the drive shaft. Furthermore, the drive cam 6 also has a drive section 6.2 with a mirror-symmetrical design (itself), thereby transmitting an external driving force, driving the wedge 5 to operate, and completing the operation of the gear pair. It is also conceivable that the drive section 6.2 can be designed to be non-mirror-symmetrical, as long as it can achieve its function. The wedge 5 is composed of two wedge segments (i.e., a left wedge segment 5.1 and a right wedge segment 5.2) designed to be mirror-symmetrical. The drive segment 6.2 of the drive cam 6 is inserted into the gap between the narrow sides (also known as the tails) of the two wedge segments. It is also conceivable that the two wedge segments can be designed to be non-mirror-symmetrical, as long as their functions are achieved. Furthermore, the recliner according to this embodiment also includes a spring 7, whose ends are connected to the mutually facing wide sides (also known as heads) of the two wedge segments. Specifically, they are inserted into two recessed portions 5.11 and 5.21 on the two wide sides facing each other, thereby forcing the two wedge segments apart through the spring 7 acting in the circumferential direction. By adjusting the spacing between the heads of the two wedge segments, the eccentricity required during operation of the recliner is instantly met. In this way, the wedge 5 and spring 7 cooperate to define an eccentric member, which is used to press the external gear of the gear plate 2 into the internal gear ring of the ring gear plate 3 in the meshing position. In some embodiments, more than two wedge segments can be provided, and springs 7 can be provided between adjacent wedge segments. Furthermore, the recliner according to this embodiment further comprises a cover 8 that covers the drive cam 6 and is connected and fixed to the ring gear plate 3 .

[0029] The specific working mechanism of the recliner according to this embodiment includes: during the driving process by rotating the drive shaft, the torque is first transmitted to the drive cam 6, and then transmitted to the eccentric piece (formed by the wedge block 5 and the spring 7) through the drive section 6.2. The eccentric piece slides along the friction bearing 4, causing its eccentric direction to shift, and thereby causing the meshing position of the external gear of the gear plate 2 in the internal gear ring of the gear ring plate 3 to shift, thereby allowing the inclination of the backrest to be continuously and variably adjusted.

[0030] As shown in Figure 1 , the recliner according to this embodiment further includes an elastic member 9 , which is composed of two separate elastic elements (i.e., a left rubber member 9.1 and a right rubber member 9.2) of a mirror-symmetrical design. These are mounted on the left wedge segment 5.1 and the right wedge segment 5.2 of the wedge block 5, respectively. It should be understood that the elastic member 9 is not limited to the rubber member shown; it can also be a spring or other elastic member, and the left rubber member 9.1 and the right rubber member 9.2 can also be asymmetrical in design.

[0031] As shown in Figure 2, the upper surfaces of the wedge segments 5.1 and 5.2 are formed with a first groove 5b and a second groove 5c separated by a boss 5a. The depth of the first groove 5b is less than that of the second groove 5c. In other embodiments, the depth of the first groove 5b may be greater than or equal to that of the second groove 5c. The lower surfaces of the rubber members 9.1 and 9.2 are formed with a first boss 9b and a second boss 9c separated by a recess 9a. The height of the first boss 9b is less than that of the second boss 9c. In other embodiments, the height of the first boss 9b may be greater than or equal to that of the second boss 9c. The first boss 9b is accommodated in the first groove 5b, and the second boss 9c is accommodated in the second groove 5c. In this manner, the rubber members 9.1 and 9.2 are positioned and mounted on the wedge segments 5.1 and 5.2.

[0032] As shown in Figure 3, the driving section 6.2 of the driving cam 6 includes an arcuate block 6a, a first protrusion 6b, and a second protrusion 6c. The arcuate block 6a and the first protrusion 6b are spaced apart to accommodate the left rubber member 9.1, while the arcuate block 6a and the second protrusion 6c are spaced apart to accommodate the right rubber member 9.2. In the assembled state, the arcuate block 6a is located in the gap between the tails of the left wedge segment 5.1 and the right wedge segment 5.2. The first protrusion 6b engages with the first groove 5b of the left wedge segment 5.1, and the second protrusion 6c engages with the first groove 5b of the right wedge segment 5.2.

[0033] The end faces of the projections 6b and 6c facing the arcuate block 6a are formed as small end faces 6d, while the end faces of the arcuate block 6a facing the projections 6b and 6c are formed as large end faces 6e. The end faces of the rubber pieces 9.1 and 9.2 facing the heads of the wedge segments 5.1 and 5.2 are formed as front end faces 9d, while the end faces of the rubber pieces 9.1 and 9.2 facing the tails of the wedge segments 5.1 and 5.2 are formed as rear end faces 9e. The left and right rubber pieces 9.1 and 9.2 are each formed integrally here, but they can also be formed in two parts, with the front end face 9d provided on the front part and the rear end face 9e provided on the rear part. These parts can be separately fixed to the left and right wedge segments 5.1 and 5.2, respectively. However, these two separate parts should still be considered together as a left rubber piece 9.1 (left elastic element) or a right rubber piece 9.2 (right elastic element). The front end face 9d contacts the small end face 6d, keeping the front end face 9d in a compressed state during operation, providing driving force for the wedge segments 5.1, 5.2 below, so that the heads of the two wedge segments 5.1, 5.2 remain open to achieve the desired eccentricity of the recliner. It should be understood that during operation, i.e., when the drive cam 6 rotates clockwise or counterclockwise, only the front end face 9d of the elastic member or rubber member 9.1 or 9.2 on one side is compressed by the small end face 6d on that side at any given moment, providing driving force for the wedge segments 5.1 or 5.2 below that side's rubber member 9.1 or 9.2. However, after reversing, the function switches to the other side, i.e., the front end face 9d of the elastic member or rubber member 9.2 or 9.1 on the other side is compressed by the small end face 6d on that side due to the rotation of the drive cam 6, providing driving force for the wedge segments 5.2 or 5.1 below that side's rubber member 9.2 or 9.1. Furthermore, the rear end surface 9e contacts the large end surface 6e, for example, during rotation of the drive cam 6, providing a buffer for the contact between the drive cam 6 and the wedge 5 during actuation or reversal of the recliner. It should be understood that the elastic member 9 can be designed with a predetermined amount of compression, such as applied by the small end surface 6d, for a more pronounced effect.

[0034] As shown in Figures 1, 4, and 5, the recliner according to this embodiment also includes a cover plate 10, which is mounted on the drive cam 6. Its primary function is to limit the elastic member 9 and keep it within its active zone. Specifically, the cover plate 10 has two radially outwardly extending ears 10a, which press against the rubber members 9.1 and 9.2, respectively. Furthermore, the cover plate 10 limits the deformation of the elastic member 9, thereby increasing its elastic force. It should be understood that the cover plate 10 can be made of metal, plastic, or other materials.

[0035] When the recliner is stationary, all components of the drive mechanism remain in a state of static equilibrium. At this point, the rubber members 9.1 and 9.2 maintain a certain degree of pre-compression contact with the small end face 6d (this can, for example, achieve a better driving effect), but have no contact with the large end face 6e. In other embodiments, the rubber members 9.1 and 9.2 can be designed to have no pre-compression contact with the small end face 6d, or to be spaced apart from each other. The circumferential distance between the large end face 6e and the tail of the wedge segments 5.1 and 5.2 is called idle travel.

[0036] When the recliner's drive mechanism is activated clockwise, the drive cam 6 rotates clockwise, increasing the compression of the small end surface 6d on the right rubber element 9.2. The right rubber element 9.2 then transmits force to the right wedge segment 5.2 below, generating a driving force on the right wedge segment 5.2. This driving force continues to increase as the drive cam 6 rotates. When the drive cam 6 is about to contact the tail of the left wedge segment 5.1, the left rubber element 9.1 forms an elastic compressive contact with the large end surface 6e of the drive cam 6, cushioning the impact between the large end surface 6e and the tail of the left wedge segment 5.1 and reducing the impact noise during startup. This can also be seen in Figures 2 and 3. The rear end faces 9e of the rubber members 9.1 and 9.2 extend circumferentially beyond the tail of the wedge segment 5.1 or 5.2 and are therefore closer to the large end face 6e. Therefore, when the rubber members 9.1 and 9.2 move toward the large end face 6e, the rear end faces 9e of the rubber members 9.1 and 9.2 can elastically abut against the large end face 6e, thereby preventing the tail of the wedge segment 5.1 or 5.2 from first colliding with the large end face 6e and producing a knocking sound.

[0037] During clockwise rotation, the large end surface 6e pushes the tail of the left wedge segment 5.1 forward. The right wedge segment 5.2, driven by the driving force transmitted from the right rubber element 9.2 (plus the preload of the spring 7), does not require the left wedge segment 5.1 to contact the spring 7 to generate thrust. This balances the friction of the right wedge segment 5.2 and allows it to be driven. Therefore, the heads of the wedge segments 5.1 and 5.2 always maintain the appropriate distance to meet the real-time eccentricity required for recliner operation. This is the principle that effectively eliminates the effect of mechanism backlash on eccentricity, thereby eliminating the jitter caused by mechanism backlash.

[0038] When switching from clockwise to counterclockwise, the mechanism's idle travel reaches its maximum, driving cam 6's impact on the tail of right wedge segment 5.2 becomes greater. Right rubber member 9.2 squeezes against its larger end surface 6e, providing a cushioning effect and reducing the impact noise during switching. Clearly, during counterclockwise operation, the aforementioned noise reduction, backlash elimination, and smoothness enhancement functions are identical to those during clockwise operation, providing bidirectional, full-stroke functionality.

[0039] In the prior art, the elastic member of the present invention and the driving process achieved by the elastic member are not provided. Instead, for example, during clockwise operation, the driving cam 6 directly contacts and drives the left wedge segment 5.1 (for example, its tail) to rotate clockwise, and the left wedge segment 5.1 then transmits the driving force to the right wedge segment 5.2 by compressing the spring 7 to drive the right wedge segment 5.2 to rotate clockwise. However, on the one hand, there is no elastic buffer between the driving cam 6 and the left wedge segment 5.1, resulting in a direct impact sound. On the other hand, the spring 7 may be over-compressed in the process of transmitting the driving force, resulting in the distance between the heads of the two wedge segments 5.1 and 5.2 becoming too small to normally compensate for the mechanism gap, thereby causing a shaking phenomenon caused by the mechanism gap. In contrast, in the present invention, the elastic member and the drive as one of the links in the drive chain can achieve: on the one hand, it avoids the rigid collision between the driving cam 6 and the tail of the wedge segments 5.1, 5.2, and plays an elastic buffering role during the collision; on the other hand, it ensures that the spring 7 is not compressed by the driving force to ensure the distance between the heads of the two wedge segments 5.1, 5.2, and avoids shaking. The above is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made according to the claims and description of the present invention application fall within the scope of protection of the claims of the patent of the present invention. The contents not fully described in the present invention are all conventional technical contents.

Claims

1. An angle adjustment device for a planetary gear train with a small tooth difference, characterized in that: The angle adjustment device includes a wedge block, a driving cam and an elastic member, wherein the wedge block is composed of two wedge-shaped segments, the driving cam has a driving segment, the driving segment includes an arc block and two protrusions spaced apart from the arc block, the arc block is inserted into the gap between the tails of the two wedge-shaped segments, and the elastic member is composed of two split elastic elements, which are respectively installed on the two wedge-shaped segments and accommodated between the arc block and the protrusions.

2. The angle adjustment device according to claim 1, characterized in that: The two wedge segments are designed to be mirror-symmetrical, and / or the drive segment is designed to be mirror-symmetrical.

3. The angle adjustment device according to claim 1, characterized in that: The end face of each protrusion facing the arc block is formed as a small end face, the end face of the arc block facing each protrusion is formed as a large end face, the end face of each elastic element facing the head of each wedge segment is formed as a front end face, and the end face of each elastic element facing the tail of each wedge segment is formed as a rear end face, the front end face cooperates with the small end face, and the rear end face cooperates with the large end face.

4. The angle adjustment device according to claim 3, characterized in that: The front end face contacts the small end face and is in a compressed state during operation, providing driving force for each wedge segment so that the heads of the two wedge segments remain spread apart to achieve the eccentricity required by the angle adjustment device.

5. The angle adjustment device according to claim 3, characterized in that: During operation, according to the rotation direction, only the front end surface of the elastic element on one side is selectively squeezed by the small end surface on that side due to the rotation of the driving cam, and provides driving force for the wedge segment on that side.

6. The angle adjustment device according to claim 3, characterized in that: The rear end face contacts the large end face, providing a buffer for the contact between the driving cam and the wedge block during starting or reversing.

7. The angle adjustment device according to claim 3, characterized in that: The rear end face of each elastic element protrudes beyond the tail of the wedge segment in the circumferential direction and is therefore closer to the large end face of the arc block, so that the rear end face of the elastic element can elastically abut against the large end face when moving toward the large end face.

8. The angle adjustment device according to claim 3, characterized in that: When at rest, each elastic element maintains a certain pre-compression contact with the small end surface and / or has no contact with the large end surface.

9. The angle adjustment device according to claim 1, characterized in that: Each wedge segment has a first groove and a second groove spaced apart by a boss, and each elastic element has a first boss and a second boss spaced apart by a recess. The first boss is accommodated in the first groove, and the second boss is accommodated in the second groove.

10. The angle adjustment device according to claim 9, characterized in that: Each projection fits into the first groove of each wedge-shaped segment.

11. The angle adjustment device according to claim 1, characterized in that: The angle adjustment device also includes a cover plate installed on the driving cam for limiting the elastic member.

12. The angle adjustment device according to claim 1, characterized in that: The angle adjustment device also includes a gear plate and a ring gear plate that can rotate relative to each other, an external gear is formed on the gear plate, and an internal gear ring is formed on the ring gear plate. The external gear and the internal gear ring are meshed with each other to form a gear pair of a small tooth difference planetary gear train.

13. The angle adjustment device according to claim 12, characterized in that: The gear plate has a collar that is concentric with the external gear. The wedge used to achieve the eccentricity of the planetary gear pair with small tooth difference is supported on the collar by its curved inner surface and carries the gear ring plate by its curved outer surface, thereby achieving the eccentric effect through the inner and outer curved surfaces.

14. The angle adjustment device according to claim 1, characterized in that: The angle adjustment device further comprises a spring disposed between the two wedge-shaped segments for biasing them away from each other.

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