Eccentric-to-concentric angle adjuster

Abstract

The invention relates to an eccentric-to-concentric angle adjuster which comprises an outer toothed plate installed on a guide plate through a cross coupling, and the surface, facing the cross coupling, of the guide plate is provided with paired transverse protrusions so that transverse sliding grooves can be formed between the transverse protrusions. The surface, facing the cross coupling, of the outer toothed plate is provided with paired vertical protrusions so that a vertical sliding groove can be formed between the vertical protrusions, the cross coupling comprises a transverse sliding block and a vertical sliding block which are vertically arranged, the transverse sliding block is contained in the transverse sliding groove to slide so as to provide contact fit, and the vertical sliding block is contained in the vertical sliding groove to slide so as to provide contact fit; the cross coupling further comprises supporting blocks or wedge-shaped blocks acting on the transverse sliding blocks and the vertical sliding blocks so that the transverse sliding blocks and the vertical sliding blocks can be expanded in the width direction to eliminate the sliding groove gaps. According to the eccentric-to-concentric angle adjuster, on the premise of low cost, all the sliding groove gaps in the cross-shaped structure are stably controlled to be not larger than 0.015 mm, and the backrest gap is greatly reduced.

Description

Technical Field

[0001] This invention relates to automobile seats, and more specifically to an eccentric to concentric angle adjuster. Background Technology

[0002] Adjusters are commonly used in car seat backrests, installed at the connection between the backrest and the seat pan to adjust the backrest. Electric adjusters, driven by a motor, can adjust the backrest forward and backward. Essentially, they are low-speed reducers, requiring them to withstand significantly higher torque compared to traditional reducers, and exhibiting almost no backlash (return play) when stopped. Adjusters can also be used to drive linkage mechanisms for seat pan height adjustment.

[0003] Currently, most electric seat back adjusters on the market are designed based on the principle of a low-tooth-difference mechanism, achieving high strength and zero backrest clearance. However, the low-tooth-difference transmission mechanism contains an eccentricity, causing the instantaneous angular velocity of the backrest to periodically fluctuate between its maximum value and zero during backrest adjustment. During low-speed (comfort) backrest adjustments, this periodic speed fluctuation is not easily noticeable. However, when used for rapid backrest folding or seat height adjustment, the periodic speed fluctuation is more easily noticed (causing discomfort) or produces abnormal noise.

[0004] There are a few concentric adjustment mechanisms on the market that can solve the problem of smooth rotation. They convert eccentric motion into concentric transmission through two orthogonal sliding pairs. However, the sliding pairs cannot significantly improve the problem of backrest clearance. In particular, the backrest frame will amplify the backrest clearance of the mechanism components by an order of magnitude (more than 10 times) through connecting rods or levers, which will also induce abnormal noise. Summary of the Invention

[0005] To address the problem of excessive backlash in existing concentric angle adjusters, this invention provides an eccentric-to-concentric angle adjuster.

[0006] According to the present invention, an eccentric to concentric angle adjuster includes an outer gear plate mounted on a guide plate via a cross coupling. The guide plate has a pair of transverse protrusions on its surface facing the cross coupling to form a transverse groove therebetween. The outer gear plate has a pair of vertical protrusions on its surface facing the cross coupling to form a vertical groove therebetween. The cross coupling includes a transverse slider and a vertical slider arranged vertically. The transverse slider is received in the transverse groove and slides to provide a contact fit. The vertical slider is received in the vertical groove and slides to provide a contact fit. The cross coupling also includes a support block or wedge block acting on the transverse slider and the vertical slider to expand the transverse slider and the vertical slider in the width direction to eliminate the groove gap.

[0007] Preferably, the horizontal slider and the vertical slider are provided by an integrated cross slider.

[0008] Preferably, the support block is cylindrical, and the cross slider has an inwardly open non-through groove, in which the support block is accommodated to expand the slider in the width direction.

[0009] Preferably, the support block is elongated, and the cross slider has an outwardly open non-through groove. The support block is accommodated in the non-through groove to expand the slider in the width direction.

[0010] Preferably, the horizontal slider and the vertical slider are provided by two or four separate sliders, and the cross coupling also includes a spring connected to the wedge block so that the wedge block has a tendency to move inward. The wedge block is accommodated between adjacent sliders with an inclined fit so that the sliders have a tendency to move away from each other.

[0011] Preferably, the top of the slider has a bend to prevent the wedge from dislodging in the radial direction.

[0012] Preferably, the eccentric to concentric angle adjuster further includes a clamp fixedly connected to the guide plate.

[0013] Preferably, the eccentric to concentric angle adjuster further includes an inner gear plate connected to the outer gear plate via gears, and the inner cylindrical surface of the clamp and the outer cylindrical surface of the inner gear plate are in clearance fit.

[0014] Preferably, the eccentric to concentric angle adjuster further includes an eccentric cam, which includes a central shaft, a wedge, and a spring. The drive shaft is connected to the central shaft. The central shaft has a cylindrical surface and a protrusion that protrudes radially outward from the cylindrical surface. The wedge is supported on the cylindrical surface by its curved inner surface and carries an inner toothed plate by its curved outer surface. The outer toothed plate is directly supported on the cylindrical surface. The protrusion is inserted into the clearance between the narrow sides of the two wedge segments of the wedge. The two ends of the spring are respectively connected to the wide sides of the two wedge segments facing each other so that the spring acts on the wedge segments in the circumferential direction to force the two wedge segments to separate.

[0015] Preferably, the central shaft also has an end step, which is clearance-fitted into the central hole of the guide plate.

[0016] Preferably, the eccentric to concentric angle adjuster further includes a cover that covers the central shaft and is fixedly connected to the internal gear plate to prevent the eccentric cam from disengaging axially.

[0017] According to the present invention, the eccentric to concentric angle adjuster can stably control the gap of all slide grooves in the cross structure at low cost (mass production possible) based on experimental tests, for example, no more than 0.015 mm, and significantly reduce the backrest gap within a limited complexity without reducing other performance. Attached Figure Description

[0018] Figure 1 This is an exploded view of an eccentric to concentric angle adjuster according to a preferred embodiment of the present invention.

[0019] Figure 2 yes Figure 1 A schematic diagram of the guide plate structure.

[0020] Figure 3 yes Figure 1 A schematic diagram of the assembly of the guide plate and the cross coupling.

[0021] Figure 4 yes Figure 1 A schematic diagram of the assembly of the cross coupling and the external gear plate.

[0022] Figure 5 This is an exploded view of the guide plate, cross coupling, and external gear plate according to another preferred embodiment of the present invention.

[0023] Figure 6 This is an exploded view of the guide plate, cross coupling, and external gear plate according to another preferred embodiment of the present invention.

[0024] Figure 7 yes Figure 6 A schematic diagram of the assembly of the cross coupling and the external gear plate.

[0025] Figure 8 yes Figure 6 A schematic diagram of the assembly of the guide plate and the cross coupling.

[0026] Figure 9 Corresponding to Figure 7 Show Figure 6 The first variant.

[0027] Figure 10 Corresponding to Figure 8 Show Figure 6 The first variant.

[0028] Figure 11 Corresponding to Figure 7 Show Figure 6 The second variant.

[0029] Figure 12 yes Figure 11 Top view. Detailed Implementation

[0030] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0031] like Figure 1As shown, an eccentric to concentric angle adjuster according to a preferred embodiment of the present invention includes a clamp 1, a guide plate 2, a cross coupling 3, an outer gear plate 4, an inner gear plate 5, a central shaft 6, a wedge 7, a spring 8, and a cover 9. The clamp 1 is fixedly connected (e.g., welded) to the guide plate 2. The outer gear plate 4 is mounted on the guide plate 2 via the cross coupling 3 so that the outer gear plate 4 can slide laterally or longitudinally along the guide plate 2. The inner gear plate 5 and the outer gear plate 4 are connected to each other via gears for adjustment and fixation. The central shaft 6 has a central bore for receiving and matching a drive shaft to brake the central shaft 6 via the drive shaft. The central shaft 6 has a cylindrical surface 61 and a protrusion 62 protruding radially outward from the cylindrical surface 61. The wedge 7... The inner gear plate 5 is supported on the cylindrical surface 61 by its curved inner surface and carries the inner gear plate 5 by its curved outer surface. The outer gear plate 4 is directly supported on the cylindrical surface 61. The protrusion 62 is inserted into the clearance between the narrow sides of the two wedge segments of the wedge block 7. The two ends of the spring 8 are respectively connected to the wide sides of the two wedge segments facing each other so that the spring 8 acts on the wedge segments in the circumferential direction to force the two wedge segments to separate, so that the eccentricity always has an expanding tendency. This is used to press the outer gear of the outer gear plate 4 into the inner gear ring of the inner gear plate 5 at the meshing position to make them mesh tightly and eliminate the clearance. The cover 9 covers the central shaft 6 and is fixedly connected (e.g., welded) to the inner gear plate 5 to prevent the central shaft 6, wedge block 7 and spring 8 from coming off axially during operation. In this embodiment, the clamp 1 is fixed on the guide plate 2 to prevent the guide plate 2, cross coupling 3, outer gear plate 4 and inner gear plate 5 from separating from each other during operation. It should be understood that the clamp 1 does not impede the relative rotation of the outer gear plate 4 and the inner gear plate 5. The inner cylindrical surface of the clamp 1 and the outer cylindrical surface of the inner gear plate 5 are in clearance fit. If the inner gear plate 5 is fixed, the guide plate 2 can rotate concentrically relative to the inner gear plate 5 around its axis. In this embodiment, the central shaft 6 also has an end step 63, which is in clearance fit within the central hole 21 of the guide plate 2. This position provides support force during transmission or when subjected to a large load. After rotation stops or the angle adjustment is completed, this position is in clearance fit and does not contact.

[0032] like Figure 2 As shown, the guide plate 2 has pairs of transverse protrusions 22 on its surface facing the cross coupling 3 to form transverse grooves 23 therebetween. Figure 1 As shown, the external gear plate 4 has a pair of vertical protrusions 41 on its surface facing the cross coupling 3 to form a vertical groove 42 therebetween. The cross coupling 3 includes a cross slider 31, which has a vertically arranged transverse slider 31a and a vertical slider 31b. The transverse slider 31a is received and slides in the transverse groove 23 (see...). Figure 3 To provide a contact fit, the vertical slider 31b is received and slides within the vertical groove 42 (see...). Figure 4To provide contact fit. In this embodiment, the guide plate 2, the cross slider 31 and the outer toothed plate 4 are all heat-treated and hardened, and the surfaces of the grooves 23 and 42 must be wear-resistant and able to withstand large impact loads.

[0033] like Figure 3 and Figure 4 As shown, after sliders 31a and 31b are placed in the grooves 23 and 42, there is a gap T on the sides of sliders 31a and 31b in the rotation direction (i.e., the width direction), which may cause sliders 31a and 31b to wobble in the rotation direction. This gap T allows the cross coupling 3 to deflect slightly under a small load torque, resulting in abnormal noise during vehicle body vibration.

[0034] like Figure 1 As shown, the cross coupling 3 also includes four support blocks 32. The sliders 31a and 31b of the cross slider 31 each have four inwardly open non-through grooves 31c. The four support blocks 32 are respectively accommodated in the four non-through grooves 31c to expand the sliders 31a and 31b in the width direction. In this embodiment, the cross slider 31 has a through hole 31d in the middle for mounting the drive shaft (synchronizing rod). The non-through grooves 31c extend from the through hole 31d from the inside to the outside but do not penetrate the sliders 31a and 31b, ensuring that the cross slider 31 is integral, thereby providing dimensional stability. In this embodiment, the support block 32 is cylindrical, also referred to as a cylindrical roller. In this embodiment, the cylindrical roller is a high-precision standard part obtained by centerless external cylindrical grinding, which has a low cost. It should be understood that the cross slider 31 is a heat-treated part, while the support blocks 32 are non-heat-treated parts made of the same or similar materials.

[0035] In the specific assembly process, the width of the transverse groove 23 of the guide plate 2, the width of the sliders 31a and 31b of the cross slider 31 of the cross coupling 3, and the width of the vertical groove 42 of the outer toothed plate 4 are accurately measured and recorded. Then, based on the premise that the widths of sliders 31a and 31b are less than the widths of grooves 23 and 42, the matching installation is performed according to the maximum overall approximation. Then, the support block 32 is interference-fitted into the non-through groove 31c, thereby reducing the gap T to the target range through the local expansion of sliders 31a and 31b. It should be understood that a series of cylindrical rollers with different outer diameters can be prepared in advance, with the inner and outer diameter dimensional fluctuations of each series ≤0.01mm. Based on the matching results, cylindrical rollers with appropriate interference fits can be selected for press fitting. There are two specific press fitting methods. One is to directly insert cylindrical rollers with larger outer diameters, the disadvantage of which is that the expansion range is not easy to control. Another method involves inserting appropriately sized cylindrical rollers. The insertion process produces minimal expansion, but subsequent upsetting using a riveting device determines the degree of upsetting through force-displacement feedback during the riveting process, thus ensuring a stable and controllable small clearance T-fit. The riveting process can occur before or after welding the clamps or connecting plates. In the post-weld riveting scheme, the guide plate 2 has through holes 24 for riveting expansion. By monitoring the pressing force and displacement curves during the riveting process, a consistent (post-riveting) target clearance can be obtained under different assembly clearances. Thus, this clearance T can be between 0 and 0.015 mm, i.e., ≤0.015 mm. In practice, a moderate interference fit is permissible, but the amount of interference must be carefully controlled.

[0036] like Figure 5 As shown, in another preferred embodiment of the eccentric-to-concentric angle adjuster according to the present invention, the support block 32' of the cross coupling is elongated, and the slider of the cross slider 31' has four outwardly open non-through grooves 31c'. The four support blocks 32' are respectively accommodated in the four non-through grooves 31c' to expand the slider in the width direction. In this embodiment, the cross slider 31 has a through hole 31d' in the middle for mounting the drive shaft (synchronizing rod). The non-through grooves 31c' extend from the outside to the inside but do not penetrate, that is, they are not connected to the through hole 31d'. In this embodiment, the support block 32' is an irregularly shaped part, provided by a companion part in the manufacturing process of the cross slider 31', and has a low cost. In the specific assembly process, the support block 32' is first pressed into the cross slider 31' with a flat key to ensure that the slider width is less than the groove width, thus completing the assembly of the eccentric-to-concentric angle adjuster. After the clamp 1 is welded, the support block 32' is stamped to expand the slider width to be close to the groove width.

[0037] like Figures 6-8As shown, in another preferred embodiment of the present invention, the cross slider of the eccentric to concentric angle adjuster is split into four L-shaped sliders 30, with two additional springs 10 and four wedge blocks 20. Each wedge block 20 is inverted conical in shape and has two inclined surfaces 21. Correspondingly, each of the four sliders 30 has two inclined surfaces 31 on its inner side, which are fitted together with the inclined surfaces 21. The springs 10 have a centripetal spring force and are installed in adjacent wedge blocks 20, causing all four wedge blocks 20 to tend to move centripetally. Under the action of the centripetal movement of the wedge blocks 20, the relative sliding of the inclined surfaces 21 and 31 causes the sliders 30 to tend to move away from each other, adhering to the transverse groove 23 on the guide plate 2 and the vertical groove 42 on the outer toothed plate 4, thereby eliminating the internal gap of the core component generated by the sliders 30. A bend 32 is present at the top of the slider 30, which, under stress, prevents the wedge blocks 20 from dislodging radially and allows the four sliders 30 to contact each other promptly under load, improving the support strength of the sliders 30.

[0038] The number of wedges is not limited to the four mentioned above; it can also be two. Correspondingly, the number of sliders can also be two. The wedges can also be changed to two rivets, such as... Figure 9 and Figure 10 As shown. The spring 10 is not limited to being installed in adjacent wedges as mentioned above; it can also be installed in two opposing wedges 20. The number of springs 10 is not limited to the two mentioned above; it can also be one, as shown. Figure 11 and Figure 12 As shown.

[0039] According to the eccentric to concentric angle adjuster of the present invention, the motor input is on the eccentric cam (central shaft 6, wedge block 7 and spring 8), the internal gear plate 5 is fixed, and the speed reduction (torque amplification) is completed through the small tooth difference structure. The external gear plate 4 has an eccentric wave motion, and the eccentricity in any direction is absorbed by the cross coupling 3, so that the guide plate 2, as the output part, rotates concentrically and uniformly, thereby achieving smooth concentric rotation and eliminating noise. Specifically, in the eccentric cam, the cam eccentricity always has an expanding tendency, and the meshing gear plates 4 and 5 are in close contact, so that there is no (obvious) gap when the backrest rockes back and forth; in the cross coupling 3, which is essentially two sliding pairs, the support block 32 expands the cross slider 31 or the wedge block 20 squeezes the expanding slider 30 to provide a controllable and particularly small gap, so that the groove gap is ≤0.015mm. It should be understood that the groove gap is formed by the superposition of the dimensions of the two parts. Due to the limitations of the part processing technology and heat treatment deformation, the tolerance zone width of a single dimension has exceeded the target value of 0.015. Specifically, for the manufacturing precision of a single part (fine stamping, powder metallurgy, considering heat treatment deformation), achieving a single-batch, single-cavity precision of ≤0.04mm is difficult, and ≤0.02mm is almost impossible. The groove clearance is formed by pairing two parts, and according to the design target, the dimensional fluctuation of a single part needs to be controlled within 0.0075. Therefore, a special process is required to achieve this assembly clearance. Traditional processes require selecting (marking) three parts to be paired, measuring the width of four grooves on two of the parts with a measurement accuracy of 0.001mm, and then performing high-precision custom grinding on the intermediate part based on the obtained values, with a machining accuracy of ~0.001mm. After grinding, laser marking, cleaning, and drying are performed before returning to the assembly line, resulting in extremely high costs. This invention, however, does not require high-precision measurement or high-precision machining, and is therefore cost-effective.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. An eccentric to concentric angle adjuster, characterized in that, The eccentric to concentric angle adjuster includes an outer gear plate mounted on a guide plate via a cross coupling. The guide plate has a pair of transverse protrusions on its surface facing the cross coupling to form a transverse groove therebetween. The outer gear plate has a pair of vertical protrusions on its surface facing the cross coupling to form a vertical groove therebetween. The cross coupling includes a vertically arranged transverse slider and a vertical slider. The transverse slider is received in the transverse groove and slides to provide a contact fit. The vertical slider is received in the vertical groove and slides to provide a contact fit. The cross coupling also includes a support block or wedge block acting on the transverse slider and the vertical slider to expand the transverse slider and the vertical slider in the width direction to eliminate the groove gap.

2. The eccentric to concentric angle adjuster according to claim 1, characterized in that, The horizontal and vertical sliders are provided by a single cross slider.

3. The eccentric to concentric angle adjuster according to claim 2, characterized in that, The support block is cylindrical, and the cross slider has an inwardly open non-through groove. The support block is accommodated in the non-through groove to expand the slider in the width direction.

4. The eccentric to concentric angle adjuster according to claim 2, characterized in that, The support block is long and narrow, and the cross slider has an outwardly open non-through groove. The support block is accommodated in the non-through groove to expand the slider in the width direction.

5. The eccentric to concentric angle adjuster according to claim 1, characterized in that, The horizontal and vertical sliders are provided by two or four separate sliders. The cross coupling also includes a spring that is connected to a wedge to give the wedge a tendency to move inward. The wedge is accommodated between adjacent sliders with an inclined fit to give the sliders a tendency to move away from each other.

6. The eccentric to concentric angle adjuster according to claim 5, characterized in that, The top of the slider has a bend to prevent the wedge from coming off in the radial direction.

7. The eccentric to concentric angle adjuster according to claim 1, characterized in that, The eccentric to concentric angle adjuster also includes a clamp that is fixedly connected to the guide plate.

8. The eccentric to concentric angle adjuster according to claim 7, characterized in that, The eccentric to concentric angle adjuster also includes an inner gear plate connected to the outer gear plate via gears, and a clearance fit between the inner cylindrical surface of the clamp and the outer cylindrical surface of the inner gear plate.

9. The eccentric to concentric angle adjuster according to claim 8, characterized in that, The eccentric to concentric angle adjuster also includes an eccentric cam, which includes a central shaft, a wedge, and a spring. The drive shaft is connected to the central shaft, which has a cylindrical surface and a protrusion that protrudes radially outward from the cylindrical surface. The wedge is supported on the cylindrical surface by its curved inner surface and carries an inner toothed plate by its curved outer surface. The outer toothed plate is directly supported on the cylindrical surface. The protrusion is inserted into the clearance between the narrow sides of the two wedge segments of the wedge. The two ends of the spring are respectively connected to the wide sides of the two wedge segments facing each other so that the spring acts on the wedge segments in the circumferential direction to force the two wedge segments to separate.

10. The eccentric to concentric angle adjuster according to claim 9, characterized in that, The central shaft also has an end step, which is clearance-fitted into the central hole of the guide plate.

11. The eccentric to concentric angle adjuster according to claim 9, characterized in that, The eccentric to concentric angle adjuster also includes a cover that covers the central shaft and is fixedly connected to the internal gear plate to prevent the eccentric cam from disengaging axially.

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