Worm and gear heavy-load compact automatic anti-backlash mechanism

Abstract

A worm and gear heavy-load compact automatic anti-backlash mechanism is applied to the technical field of precision mechanical transmission. The worm gear and the worm are mounted in the box body, the bearing is connected with a driving end at one end of the worm, the other end of the worm is provided with a sliding bearing seat, the sliding bearing seat and a bearing component in the sliding bearing seat are axially fixed with the worm, and an anti-backlash spring group is arranged on one side, far away from the worm gear, of the sliding bearing seat; a limiting nut of the anti-backlash spring group is in threaded connection with the box body and is arranged in the concave spherical surface direction of the box body and the sliding bearing seat; a connecting flange connected to the box body is in threaded connection with the jacking screw rod; the small end of the mandrel penetrates through the spring and is sleeved in an inner hole of the outer spherical pad; two ends of the spring are pressed between the positioning blind hole of the outer spherical pad and the positioning shaft shoulder of the large end of the mandrel; the convex spherical surface of the outer spherical pad is matched and contacted with the concave spherical surface of the jacking screw rod; and the convex spherical surface of the large end of the mandrel is matched and contacted with the concave spherical surface of the sliding bearing seat. The device is high in integration level, high in bearing capacity, easy to use, low in cost and capable of achieving automatic clearance elimination of the tooth surface of the worm gear and the worm.

Description

Technical Field

[0001] This invention relates to the field of precision mechanical transmission technology, specifically a heavy-duty, compact, automatic backlash elimination mechanism for worm gears. Background Technology

[0002] In mechanical transmission processes, worm gear mechanisms are frequently used. The tooth surfaces of the worm wheel and worm are prone to wear and gaps, especially in heavy-duty applications where the contact stress between the tooth surfaces is high, leading to faster tooth wear and easily resulting in backlash. In precision transmission mechanisms, it is necessary to minimize the tooth surface backlash of the worm gear, and once backlash occurs, its impact on transmission accuracy must be eliminated.

[0003] Existing worm gear backlash elimination mechanisms either employ axial floating of the worm to adjust backlash, with the backlash elimination direction aligned with the direction of the maximum component force exerted by the worm wheel on the worm, which risks reducing the load-bearing capacity of the worm gear transmission mechanism; or use structures such as double worm single worm wheel or double worm wheel single worm to eliminate backlash, but this results in a bulky and space-constrained backlash elimination structure; or use screw adjustment or periodic manual adjustment to eliminate the tooth surface backlash of the worm gear, but these methods cannot automatically eliminate the tooth surface backlash caused by wear between the worm gear and worm. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a heavy-duty compact automatic backlash elimination mechanism for worm gears, so as to automatically eliminate the tooth surface backlash of worm gears.

[0005] To achieve the above-mentioned objectives, the worm wheel and worm of the worm gear heavy-duty compact automatic backlash elimination mechanism of the present invention are installed in a housing. A bearing installed inside the housing is connected to the drive end of one end of the worm. The inner hole of the drive end of the worm is connected to a drive element via a universal joint. The drive element inputs torque power to the worm. The drive element is fixed on the housing, and its output shaft is connected to the universal joint. The other end of the worm is provided with a sliding bearing seat that can slide along a groove inside the housing. The sliding bearing seat and the bearing assembly inside it are axially fixed to the worm. A backlash elimination spring assembly is provided on the side of the sliding bearing seat away from the worm wheel.

[0006] Furthermore, the force-applying center line of the backlash-eliminating spring assembly to the sliding bearing seat is parallel to the direction of the worm gear center plane N.

[0007] Furthermore, the direction of the inner sliding groove of the housing is parallel to the direction of the worm gear center plane N, so that the sliding bearing seat can swing and slide towards the worm gear around the self-aligning center of the bearing along the direction parallel to the worm gear center plane N.

[0008] Furthermore, the backlash-eliminating spring assembly consists of a lead screw, a connecting flange, an outer spherical pad, a spring, a mandrel, and a limiting nut. The external thread of the limiting nut, which limits the maximum center distance of the worm gear, engages with the internal thread on the housing. The limiting nut is installed in the concave spherical direction of the sliding bearing seat, and the inner hole of the limiting nut is coaxial with the inner hole of the connecting flange. The connecting flange is fixedly connected to the housing, and its inner hole is an internal thread that engages with the external thread of the lead screw used to adjust the spring's jacking force. The small end of the mandrel passes through the spring and is inserted into the inner hole of the outer spherical pad. Both ends of the spring press against the positioning blind hole of the outer spherical pad and the positioning shoulder of the large end of the mandrel. The convex spherical surface of the outer spherical pad is in contact with the concave spherical surface of the lead screw, and the convex spherical surface of the large end of the mandrel is in contact with the concave spherical surface of the sliding bearing seat.

[0009] Furthermore, the bearing is a self-aligning bearing, with the outer ring of the bearing axially fixed to the housing, the inner ring of the bearing axially fixed to the worm gear, and the self-aligning swing center of the bearing coinciding with the rotation center of the universal joint.

[0010] Furthermore, the distance L between the top of the convex spherical surface of the outer spherical pad and the top of the convex spherical surface of the mandrel is greater than or equal to the sum of the spherical radius R1 of the convex spherical surface of the outer spherical pad and the spherical radius R2 of the convex spherical surface of the mandrel; the distance between the center of the convex spherical surface of the mandrel and the center of the convex spherical surface of the outer spherical pad is ≥0.

[0011] Furthermore, the transmission universal joint is a combination structure of the spline hole of the worm and the ball spline, or a combination structure of the inner hole of the worm and the ball cage universal joint, and the driving element is connected to the inner sleeve part of the transmission universal joint.

[0012] In this invention, after a gap is generated between the tooth surfaces of the worm wheel and the cylindrical worm during meshing, the screwing depth of the jacking screw in the connecting flange is adjusted to adjust the jacking force of the spring on the sliding bearing seat. Under the driving force of the spring on the sliding bearing seat on one side of the worm, the worm swings around the center of the self-aligning bearing at the worm drive end toward the worm wheel to reduce the gap between the worm wheel and the worm.

[0013] Compared with the prior art, the present invention has the following advantages: 1. High integration, compact structure, and strong load-bearing capacity. The functional components of the worm gear backlash elimination mechanism are all compactly arranged around the bearings of the worm. At the same time, because it adopts a radial backlash elimination method along the worm, it has a stronger load-bearing capacity and occupies less space compared to the axial backlash elimination mechanism.

[0014] 2. Simple to use and easy to maintain. A spring applies radial force to the worm gear to eliminate the tooth backlash. The spring pressure is adjusted during assembly using a lead screw, and no further manual adjustment is required during use.

[0015] 3. Low cost. The structure is simple and the parts are not complex, so the cost is relatively low while still meeting the backlash elimination function. Attached Figure Description

[0016] Figure 1 This is a simplified schematic diagram of the structure of the present invention.

[0017] Figure 2 for Figure 1 An enlarged schematic diagram of the structure at point A.

[0018] Figure 3 for Figure 1 Enlarged cross-sectional view of section BB.

[0019] Figure 4 This is a simplified isometric diagram of the present invention.

[0020] Figure 5 This is an overall external view of the present invention.

[0021] In the diagram: 1. Worm gear; 2. Housing; 3. Bearing; 4. Transmission universal joint; 5. Worm wheel; 6. Sliding bearing seat; 7. Lead screw; 8. Connecting flange; 9. Outer spherical gasket; 10. Spring; 11. Mandrel; 12. Limit nut; 13. Drive element. Detailed Implementation

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of protection of this invention.

[0023] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the worm wheel 5 and worm 1 of the worm gear heavy-duty compact automatic backlash elimination mechanism of the present invention are installed inside the housing 2. The bearing 3 installed inside the housing 2 is connected to the drive end of one end of the worm 1. The inner hole of the drive end of the worm 1 is connected to the drive element 13 through the transmission universal joint 4. The drive element 13 inputs torque power to the worm 1. The drive element 13 is fixed on the housing 2, and its output shaft is connected to the transmission universal joint 4. The other end of the worm 1 is provided with a sliding bearing seat 6 that can slide along the sliding groove inside the housing 2. The sliding bearing seat 6 and the bearing assembly inside it are axially fixed to the worm 1. A backlash elimination spring assembly is provided on the side of the sliding bearing seat 6 away from the worm wheel 5. The force center line of the backlash elimination spring assembly on the sliding bearing seat 6 is parallel to the direction of the worm wheel center plane N.

[0024] Preferably, the inner sliding groove of the housing 2 is machined to be parallel to the direction of the worm gear center plane N, so that the sliding bearing seat 6 can swing and slide towards the worm wheel 5 around the self-aligning center of the bearing 3 along the direction parallel to the worm gear center plane N.

[0025] Preferably, the backlash-eliminating spring assembly mainly consists of a lead screw 7, a connecting flange 8, an outer spherical washer 9, a spring 10, a spindle 11, and a limiting nut 12; the external thread of the limiting nut 12 engages with the internal thread on the housing 2, and the limiting nut 12 is used to limit the maximum center distance of the worm gear; the limiting nut 12 is installed in the concave spherical direction of the sliding bearing seat 6, and the inner hole of the limiting nut 12 is coaxial with the inner hole of the connecting flange 8; the connecting flange 8 is fixedly connected to the housing 2. Its inner hole is internally threaded, which meshes with the external thread of the jacking screw 7. The jacking screw 7 is used to adjust the jacking force of the spring 10. The small end of the mandrel 11 passes through the spring 10 and is fitted into the inner hole of the outer spherical pad 9. The two ends of the spring 10 press against the positioning blind hole of the outer spherical pad 9 and the positioning shoulder of the large end of the mandrel 11. The convex spherical surface of the outer spherical pad 9 is in contact with the concave spherical surface of the jacking screw 7, and the convex spherical surface of the large end of the mandrel 11 is in contact with the concave spherical surface of the sliding bearing seat 6.

[0026] Preferably, the bearing 3 is a self-aligning bearing. The outer ring of the bearing 3 is axially fixed to the housing 2, and the inner ring of the bearing 3 is axially fixed to the worm 1. Through assembly adjustment, the self-aligning swing center of the bearing 3 coincides with the rotation center of the transmission universal joint 4 to avoid vibration caused by the misalignment of the input and output torque power of the worm 1. The transmission universal joint 4 is a combination structure of the spline hole and the ball spline of the worm 1, or a combination structure of the inner hole of the worm 1 and the ball cage universal joint. The drive element 13 is connected to the inner sleeve of the transmission universal joint 4.

[0027] Preferably, the distance L between the top of the convex spherical surface of the outer spherical pad 9 and the top of the convex spherical surface of the spindle 11 is greater than or equal to the sum of the spherical radius R1 of the convex spherical surface of the outer spherical pad 9 and the spherical radius R2 of the convex spherical surface of the spindle 11; the distance between the center of the convex spherical surface of the spindle 11 and the center of the convex spherical surface of the outer spherical pad 9 is ≥0; the present invention, through the mutual cooperation between the concave spherical surface of the lead screw 7, the convex spherical surface of the outer spherical pad 9, the convex spherical surface of the spindle 11, and the concave spherical surface of the sliding bearing seat 6, can ensure that the center line of the force applied by the spring 10 to the sliding bearing seat 6 is always parallel to the direction of the worm gear center plane N.

[0028] This invention first limits the maximum sliding position of the sliding bearing seat 6 by using the limiting nut 12, so that the center distance between the worm gear and worm is within the standard range, thereby obtaining a suitable meshing state of the worm gear teeth in advance. Then, by adjusting the screw depth of the jacking screw 7 in the connecting flange 8, the jacking force of the spring 10 on the sliding bearing seat 6 is adjusted, so that the center distance between the worm 1 and the worm gear 5 tends to decrease.

[0029] When the worm gear transmission mechanism has been working for a period of time, and gaps are generated between the tooth surfaces due to wear, the sliding bearing seat 6, under the force of the spring 10, swings and slides towards the worm wheel 5 along the direction parallel to the center plane N of the worm gear and worm wheel, around the self-aligning center of the bearing 3. At this time, the center distance between the worm gear and worm wheel decreases, the tooth surfaces mesh tightly again, and the tooth gap is automatically eliminated.

[0030] The above embodiments are preferred examples for implementing the present invention, illustrating and describing the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heavy-duty, compact, automatic backlash elimination mechanism for worm gears, characterized in that: The worm wheel (5) and worm (1) are installed inside the housing (2). The bearing (3) inside the housing (2) is connected to the drive end of one end of the worm (1). The inner hole of the drive end of the worm (1) is connected to the drive element (13) through the transmission universal joint (4). The drive element (13) inputs torque power to the worm (1). The drive element (13) is fixed on the housing (2), and its output shaft is connected to the transmission universal joint (4). The other end of the worm (1) is provided with a sliding bearing seat (6) that can slide along the sliding groove inside the housing (2). The sliding bearing seat (6) and the bearing assembly inside it are axially fixed to the worm (1). A backlash elimination spring assembly is provided on the side of the sliding bearing seat (6) away from the worm wheel (5).

2. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 1, characterized in that: The force-applying center line of the backlash-eliminating spring assembly to the sliding bearing seat (6) is parallel to the direction of the worm gear center plane N.

3. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 1, characterized in that: The inner groove of the housing (2) is parallel to the direction of the worm gear center plane N, so that the sliding bearing seat (6) can swing and slide around the center of the bearing (3) toward the worm gear (5) along the parallel direction of the worm gear center plane N.

4. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 1, characterized in that: The backlash-eliminating spring assembly consists of a lead screw (7), a connecting flange (8), an outer spherical pad (9), a spring (10), a spindle (11), and a limiting nut (12). The external thread of the limiting nut (12), which limits the maximum center distance of the worm gear, meshes with the internal thread on the housing (2). The limiting nut (12) is installed in the concave spherical direction of the sliding bearing seat (6), and the inner hole of the limiting nut (12) is coaxial with the inner hole of the connecting flange (8). The connecting flange (8) is fixedly connected to the housing (2), and its... The inner hole is internally threaded and meshes with the external thread of the jacking screw (7) used to adjust the jacking force of the spring (10); the small end of the mandrel (11) passes through the spring (10) and is fitted into the inner hole of the outer spherical pad (9); the two ends of the spring (10) press against the positioning blind hole of the outer spherical pad (9) and the positioning shoulder of the large end of the mandrel (11); the convex spherical surface of the outer spherical pad (9) is in contact with the concave spherical surface of the jacking screw (7), and the convex spherical surface of the large end of the mandrel (11) is in contact with the concave spherical surface of the sliding bearing seat (6).

5. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 1, characterized in that: The bearing (3) is a self-aligning bearing. The outer ring of the bearing (3) is axially fixed on the housing (2), and the inner ring of the bearing (3) is axially fixed with the worm (1). The self-aligning swing center of the bearing (3) coincides with the rotation center of the transmission universal joint (4).

6. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 4, characterized in that: The distance L between the top of the convex spherical surface of the outer spherical pad (9) and the top of the convex spherical surface of the mandrel (11) is greater than or equal to the sum of the spherical radius R1 of the convex spherical surface of the outer spherical pad (9) and the spherical radius R2 of the convex spherical surface of the mandrel (11); the distance between the center of the convex spherical surface of the mandrel (11) and the center of the convex spherical surface of the outer spherical pad (9) is ≥0.

7. The worm gear heavy-duty compact automatic backlash elimination mechanism according to claim 1, characterized in that: The transmission universal joint (4) is a combination structure of spline hole and ball spline of worm (1), or a combination structure of inner hole of worm (1) and ball cage universal joint. The driving element (13) is connected to the inner sleeve of transmission universal joint (4).

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