Structure and method for reducing axial movement of eccentric bearing of recirculating ball steering gear

Abstract

The structure comprises a shell, a swing arm, a first eccentric bearing, a second eccentric bearing, a first blocking piece and a second blocking piece, and the first eccentric bearing, the second eccentric bearing, a first clamping spring groove, a second clamping spring groove, a first clamping spring and a second clamping spring are arranged in the shell. The bottom ends of the outer circumferences of the first O-shaped ring, the second O-shaped ring, the left side end dustproof oil seal, the output end dustproof oil seal, the first rocker arm shaft oil seal, the second rocker arm shaft oil seal, the first clamp spring groove and the second clamp spring groove are conical surfaces; according to the recirculating ball steering gear for improving the eccentric bearing structure, the problems of abrasion, failure and assembly interference of a sealing piece caused by axial movement of the eccentric bearing are solved.

Description

Technical Field

[0001] This invention relates to the field of recirculating ball steering technology, and specifically to a structure and method for reducing the axial movement of the eccentric bearing in a recirculating ball steering system. Background Technology

[0002] Figure 1 This diagram illustrates a recirculating ball hydraulic power steering system. The rocker arm shaft sector gears employ a uniform thickness straight tooth profile, and an eccentric bearing is used to adjust the clearance of the gear pair. This eccentric bearing structure is suitable for recirculating ball mechanical steering systems, recirculating ball hydraulic power steering systems, recirculating ball electro-hydraulic power steering systems, and recirculating ball electric power steering systems. The housing is machined with first and second snap ring grooves and first and second riveting grooves, and a first O-ring and a second O-ring are installed thereon. Along the axial direction of the recirculating ball steering system rocker arm shaft, the system includes a first snap ring, a first eccentric bearing, a rocker arm shaft, a first baffle, a second baffle, a second eccentric bearing, and a second snap ring. The snap ring is used to limit the position of parts on the shaft. Furthermore, a dust seal and an output end dust seal are respectively installed on the first and second eccentric bearings. The long and short ends of the rocker arm shaft have the same shaft diameter and are supported by the first and second eccentric bearings. First and second rocker arm shaft oil seals are also installed in the first and second eccentric bearings, respectively. The eccentric bearing has a fixed eccentricity 'e' between its roller envelope and the outer ring. During steering gear assembly, the phase of the outer rings of the first and second eccentric bearings is changed by synchronously rotating them, thereby adjusting the gear pair's meshing clearance. The meshing clearance adjustment range is between 0 and 'e'. After adjustment, the flanges on the outer rings of the two eccentric bearings are punched into the corresponding riveting grooves on the housing, thus fixing the phase of the eccentric bearing outer rings. This prevents direct friction between the gear sector end face and the bearing roller end face, thus avoiding abnormal noise. Dustproof oil seals and output end dustproof oil seals are installed on the first and second eccentric bearings respectively, and they are also equipped with bosses for sealing the riveting grooves.

[0003] The current problems with this structure are as follows: 1. The axial clearance of the eccentric bearing in this structure should be designed within a suitable range. The design principle for the axial clearance is to minimize it while ensuring that the retaining ring can be installed in the retaining ring groove. The axial dimension along the rocker arm shaft involves eight parts, including the first retaining ring, the first eccentric bearing, the rocker arm shaft, the first baffle, the second baffle, the second eccentric bearing, the second retaining ring, and the retaining ring groove spacing in the housing. The cumulative axial dimensional tolerances of these eight parts can lead to a larger axial clearance in the eccentric bearing. Although the rocker arm shaft of this structure does not generate axial force during operation, the steering arm will exert a certain axial force on the rocker arm shaft. If the axial clearance is too large, the eccentric bearing will experience axial movement, causing wear on the O-ring and the rocker arm shaft oil seal, resulting in steering gear oil leakage.

[0004] 2. The original snap ring groove 22 is as follows Figure 2As shown in the flat-bottomed groove, if the axial clearance is too large, the retaining ring can also move axially. In addition, the riveting cannot completely fix the circumferential phase of the eccentric bearing, which can still rotate slightly. When the retaining ring is pressed by the eccentric bearing, the slight rotation of the eccentric bearing will drive the retaining ring to rotate slightly through friction. With the accumulation of many slight rotations, the retaining ring will generate a large circumferential displacement, causing the boss of the dust seal to be cut off by the opening of the retaining ring, and the function of the dust seal to fail.

[0005] 3. See Figure 2 Because the cutting tool for the circlip groove 22 has rounded corners, the actual two ends of the circlip groove are rounded to the bottom. After the circlip is installed in the circlip groove, it cannot fit tightly against the end face of the groove. The influence of the rounded corners must be considered when designing the dimensional chain; otherwise, the actual axial clearance will be too small, and the outer ring of the eccentric bearing will be difficult to adjust.

[0006] Therefore, controlling the axial clearance of the eccentric bearings (6, 13) within an appropriate range has a significant impact on the sealing performance and lifespan of the eccentric bearing recirculating ball steering gear. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a structure for reducing the axial movement of the eccentric bearing in a recirculating ball steering gear, so as to improve the problem of wear, failure of seals and assembly interference caused by the axial movement of the eccentric bearing in the recirculating ball steering gear.

[0008] To solve the above problems, the present invention adopts the following technical solution: A structure for reducing axial movement of eccentric bearings in a recirculating ball steering system includes a housing, a rocker arm, a first eccentric bearing, a second eccentric bearing, a first baffle, and a second baffle. The housing houses the first and second eccentric bearings. The rocker arm is rotatably connected within the first and second eccentric bearings. The housing has a first circlip groove and a second circlip groove distributed on its left and right sides, respectively housing a first circlip and a second circlip. The housing also has a first O-ring and a second O-ring respectively built into its left and right ends. It has a dustproof oil seal on the left end and a dustproof oil seal on the output end. The first eccentric bearing and the second eccentric bearing are internally fitted with the first rocker arm shaft oil seal and the second rocker arm shaft oil seal between them. The bottom of the outer circumference of the first snap ring groove and the second snap ring groove is a conical surface. The inner end of the first snap ring groove and the second snap ring groove is provided with a small end face. The outer end of the first snap ring groove and the second snap ring groove is provided with a large end face. The conical surface and the large end face are rounded. The diameter of the small end face is smaller than the diameter of the first snap ring or the second snap ring. The width of the first snap ring groove and the second snap ring groove is greater than the thickness of the first snap ring and the second snap ring.

[0009] A further technical solution is that the left and right sides of the housing are respectively provided with a first riveting groove and a second riveting groove, the dustproof oil seal on the left side is located in the first riveting groove and is set to abut against the first snap ring, and the dustproof oil seal on the output end is located in the second riveting groove and is set to abut against the second snap ring.

[0010] A further technical solution is that the first baffle is located between the first eccentric bearing and the rocker arm, and the second baffle is located between the second eccentric bearing and the rocker arm.

[0011] A further technical solution is a design and installation method for a structure to reduce the axial movement of the eccentric bearing in a recirculating ball steering gear. The specific steps are as follows: a. Grouping the snap rings: Based on the allowable axial clearance and the minimum thickness of the snap ring (determined according to the strength of the snap ring), the snap rings are divided into several groups according to their thickness. The difference in nominal thickness between the middle group and the largest and smallest groups is the allowable clearance. This reduces the tolerance range of the tooth width of the gear sector, the distance from the eccentric bearing flange to the end face of the roller, the thickness of the snap ring, and the distance between the large end faces of the snap ring grooves on both sides. b. Based on the assembly dimension chain of the steering gear rocker arm shaft system shown in the figure (where A - thickness of the first retaining circumference, A' - thickness of the second retaining circumference, B - distance from the flange of the eccentric bearing to the end face of the roller, C - thickness of the retaining plate, D - tooth width of the rocker arm shaft gear sector, E - distance between the large ends of the retaining circumference grooves at both ends, F - allowable axial clearance), first calculate the thickness of the first retaining circumference as the intermediate group, the thickness of the first retaining circumference A, the distance from the flange of the first or second eccentric bearing to the end face of the roller B, the thickness of the first or second retaining plate C, and the thickness of the first or second retaining plate C. The tooth width D of the middle sector of the rocker arm is taken with the upper deviation, and the second circlip groove is the smallest group. When the deviation is taken down, the distance Emax between the large ends of the two circlip grooves is calculated. Similarly, the thickness A of the first circlip, the distance B from the flange of the first or second eccentric bearing to the end face of the roller, the thickness C of the first or second baffle, and the tooth width D of the middle sector of the rocker arm are all taken with the lower deviation, and the second circlip groove is the largest group. When the upper deviation is taken, the distance Emin between the large ends of the two circlip grooves is calculated. The design value of dimension E can be determined based on Emax and Emin. c. After fitting the first and second baffles onto both ends of the rocker arm shaft, place it into the housing with the first and second O-rings installed, and install the first and second eccentric bearings with the first and second rocker arm shaft oil seals installed. d. Select the intermediate group for the first retaining ring and install the first retaining ring into the first retaining ring slot.

[0012] e. Press the flange of the first eccentric bearing against the first retaining ring, and then measure the distance from the flange of the second eccentric bearing to the large end face of the second retaining ring groove.

[0013] f. Based on the measured distance, select a suitable set of second snap rings and install them into the second snap ring slot. Then, press the second snap ring against the second eccentric bearing to eliminate the axial clearance between the parts of the first and second snap rings. Measure the clearance between the large end face of the second snap ring and the large end face of the second snap ring slot. If the clearance is greater than the allowable axial clearance, increase the size of the second snap ring by one set. g. Synchronously adjust the outer ring phase of the first and second eccentric bearings until the clearance of the gear pair is appropriate; h. Punch the corresponding positions of the flanges of the first eccentric bearing and the second eccentric bearing into the first and second riveting grooves; i. Install the dustproof oil seal on the left side and the dustproof oil seal on the input side.

[0014] The beneficial effects of the present invention on the structure for reducing axial movement of eccentric bearings in a recirculating ball steering gear are as follows: 1) The first and second snap ring slots are tapered, with the smaller diameter side facing the rocker arm shaft gear sector. After the first and second snap rings are installed in the first and second snap ring slots, they will move towards the larger end face of the first and second snap ring slots under their own tension, crossing the rounded corners of the first and second snap ring slots until they are in close contact with the larger end face. During the operation of the steering gear, the first and second snap rings will not move axially. When the first and second snap rings tend to rotate, the static friction between their end face and the larger end face of the first and second snap ring slots will prevent them from rotating, thereby preventing the dust seal on the left end and the dust seal on the output end from being cut off by the opening of the first and second snap rings. Therefore, this structure is not only simple, but also effectively improves the problem of axial movement and rotation of the snap rings. 2) The first and second retaining rings are grouped according to their thickness. The distance between the large ends of the first and second retaining ring grooves is designed according to the assembly dimension chain, and the influence of the groove bottom fillet can be ignored, simplifying the dimension chain design. During steering gear assembly, the axial clearance of the rocker arm shaft system can be controlled within the allowable range by replacing the second retaining ring at most once. This reduces the axial movement of the eccentric bearing and the rotation of the first and second retaining rings, preventing abnormal wear and failure of the O-ring, rocker arm shaft oil seal, left end dust seal, and output end dust seal. Furthermore, this method is simple to operate and highly efficient. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings required for the work described in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the original eccentric bearing shaft structure of the recirculating ball steering gear. Figure 2 This is a schematic diagram of the original snap ring groove in the original eccentric bearing shaft structure of the recirculating ball steering gear; Figure 3 This is a schematic diagram of a structure for reducing axial movement of eccentric bearings in a recirculating ball steering gear according to the present invention.

[0017] Figure 4 This is a schematic diagram of the second snap ring groove in a structure for reducing axial movement of an eccentric bearing in a recirculating ball steering gear according to the present invention; Figure 5 This is a schematic diagram of the rocker arm shaft assembly dimension chain in a structure for reducing axial movement of the eccentric bearing in a recirculating ball steering gear according to the present invention.

[0018] Figure 3-5 In the middle: 1-House, 2-First O-ring, 3-First circlip groove, 4-First circlip, 5-Left side dustproof oil seal, 6-First eccentric bearing, 7-Rock arm shaft, 8-First baffle, 9-First riveting groove, 11-Second riveting groove, 12-Second baffle, 13-Second eccentric bearing, 14-Output end dustproof oil seal, 15-Second circlip, 16-Second circlip groove, 17-Second O-ring, 18-First rocker arm shaft oil seal, 19-Second rocker arm shaft oil seal, 20-Large end face, 21-Small end face. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the scope of protection of the present invention.

[0020] See Figure 3 and Figure 5As shown, a structure for reducing axial movement of an eccentric bearing in a recirculating ball steering gear includes a housing 1, a rocker arm 7, a first eccentric bearing 6, a second eccentric bearing 13, a first baffle 8, and a second baffle 12. The housing 1 houses the first eccentric bearing 6 and the second eccentric bearing 13. The rocker arm 7 is rotatably connected within the first eccentric bearing 6 and the second eccentric bearing 13. The housing 1 has a first circlip groove 3 and a second circlip groove 16 distributed on its left and right sides. The first circlip groove 3 and the second circlip groove 16 respectively house a first circlip 4 and a second circlip 15. The left and right ends of the housing 1 respectively house a first O-ring 2 and a second O-ring 17. The left and right ends of the housing 1 also house... Dustproof oil seal 5 at the left end and dustproof oil seal 14 at the output end are provided. First rocker arm shaft oil seal 18 and second rocker arm shaft oil seal 19 are built between the first eccentric bearing 6 and the second eccentric bearing 13 and the rocker arm 7. The bottom of the outer circumference of the first snap ring groove 3 and the second snap ring groove 16 is a conical surface. The inner end of the first snap ring groove 3 and the second snap ring groove 16 is provided with a small end face 21. The outer end of the first snap ring groove 3 and the second snap ring groove 16 is provided with a large end face 20. The conical surface and the large end face 20 are rounded. The diameter of the small end face 21 is smaller than the diameter of the first snap ring 4 or the second snap ring 1. The width of the first snap ring groove 3 and the second snap ring groove 16 is greater than the thickness of the first snap ring 4 and the second snap ring 15.

[0021] The left and right sides of the housing 1 are respectively provided with a first riveting groove 9 and a second riveting groove 11. The dustproof oil seal 5 on the left side is located in the first riveting groove 9 and is mutually abutting with the first retaining spring 4. The dustproof oil seal 14 on the output end is located in the second riveting groove 11 and is mutually abutting with the second retaining spring 15.

[0022] The first baffle 8 is located between the first eccentric bearing 6 and the rocker arm 7, and the second baffle 12 is located between the second eccentric bearing 13 and the rocker arm 7.

[0023] The design and installation method for a structure to reduce axial movement of the eccentric bearing in a recirculating ball steering gear is as follows: a. Grouping the snap rings: Based on the allowable axial clearance and the minimum thickness of the snap ring (determined according to the strength of the snap ring), the snap rings are divided into several groups according to their thickness. The difference in nominal thickness between the middle group and the largest and smallest groups is the allowable clearance. This reduces the tolerance range of the tooth width of the gear sector, the distance from the eccentric bearing flange to the end face of the roller, the thickness of the snap ring, and the distance between the large end faces of the snap ring grooves on both sides. b. According to... Figure 3The assembly dimension chain of the steering gear rocker arm shaft system is shown below (where A - thickness of the first retaining circlip, A' - thickness of the second retaining circlip, B - distance from the flange of the eccentric bearing to the end face of the roller, C - thickness of the baffle plate, D - tooth width of the rocker arm shaft gear sector, E - distance between the large ends of the retaining circlip grooves at both ends, F - allowable axial clearance). First, calculate the thickness of the first retaining circlip 4 as the intermediate group, the thickness of the first retaining circlip 4 (A), the distance from the flange of the first eccentric bearing 6 or the second eccentric bearing 13 to the end face of the roller (B), the thickness of the first baffle plate 8 or the second baffle plate 12 (C), and the thickness of the rocker arm 7. The tooth width D of the inter-tooth sector is taken as the upper deviation, and the second snap ring groove 16 is the smallest group. When the deviation is taken down, the distance Emax between the large ends of the snap ring grooves at both ends is calculated. Similarly, the thickness A of the first snap ring 4, the distance B from the flange of the first eccentric bearing 6 or the second eccentric bearing 13 to the end face of the roller, the thickness C of the first baffle 8 or the second baffle 12, and the tooth width D of the inter-tooth sector in the middle of the rocker arm 7 are all taken down, and the second snap ring groove (16) is the largest group. When the upper deviation is taken, the distance Emin between the large ends of the snap ring grooves on both sides is calculated. The design value of dimension E can be determined based on Emax and Emin. c. After fitting the first baffle 8 and the second baffle 12 onto both ends of the rocker arm shaft 7, place it into the housing 1 with the first O-ring 2 and the second O-ring 17 installed, and install the first eccentric bearing 6 and the second eccentric bearing 13 with the first rocker arm shaft oil seal 18 and the second rocker arm shaft oil seal 19 installed. d. The first retaining ring 4 is selected from the intermediate group, and the first retaining ring 4 is installed into the first retaining ring groove 3.

[0024] e. Press the flange of the first eccentric bearing 6 against the first retaining ring 4, and then measure the distance from the flange of the second eccentric bearing 13 to the large end face of the second retaining ring groove 16.

[0025] f. Based on the measured distance, select a suitable set of second snap rings 15 and install them into the second snap ring groove 16. Then, press the second snap rings 15 and the second eccentric bearing 13 together to eliminate the axial clearance between the parts of the first snap ring 4 and the second snap ring 15. Measure the clearance between the large end face of the second snap ring 15 and the large end face of the second snap ring groove 16. If the clearance is greater than the allowable axial clearance, increase the size of the second snap ring 15 by one set. g. Synchronously adjust the outer ring phase of the first eccentric bearing 6 and the second eccentric bearing 13 until the clearance of the gear pair is appropriate; h. Punch the corresponding positions of the flanges of the first eccentric bearing 6 and the second eccentric bearing 13 into the first riveting groove 9 and the second riveting groove 11; i. Install the dustproof oil seal 5 on the left end and the dustproof oil seal 14 on the input end.

[0026] Combining the design method and assembly process of dimension E above, during assembly, the axial clearance of the rocker arm shaft system can be controlled within the allowable range by replacing the second retaining ring 15 at most once. This reduces the axial movement of the eccentric bearing and the rotation of the retaining ring, preventing abnormal wear and failure of the first O-ring 2, the second O-ring 17, the first rocker arm shaft oil seal 18, the second rocker arm shaft oil seal 19, the dust seal 5, and the output end dust seal 14. Furthermore, this method is simple to operate and has high efficiency.

[0027] Eccentric bearing recirculating ball steering systems, including recirculating ball mechanical steering systems, recirculating ball hydraulic power steering systems, recirculating ball electro-hydraulic power steering systems, and recirculating ball electric power steering systems, shall all use the structures and methods provided in this patent within the scope of this patent.

[0028] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without creative effort should be covered within the scope of protection of the present invention.

Claims

1. A structure for reducing axial movement of eccentric bearings in a recirculating ball steering gear, characterized in that: The device includes a housing, a rocker arm, a first eccentric bearing, a second eccentric bearing, a first baffle, and a second baffle. The housing houses the first and second eccentric bearings. The rocker arm is rotatably connected within the first and second eccentric bearings. The housing has a first circlip groove and a second circlip groove distributed on its left and right sides, respectively housing a first circlip and a second circlip. The housing also has a first O-ring and a second O-ring installed on its left and right sides, respectively. A left-side dust seal and an output-side dust seal are installed on the left and right sides of the housing. A first rocker arm shaft oil seal and a second rocker arm shaft oil seal are installed between the first and second eccentric bearings and the rocker arm. The bottom of the outer circumference of the first and second circlip grooves is a conical surface. The inner ends of the first and second circlip grooves have small end faces, and the outer ends have large end faces. The conical surface and the large end face are rounded. The diameter of the small end face is smaller than the diameter of the first or second circlip. The width of the first and second circlip grooves is greater than the thickness of the first and second circlips.

2. A structure for reducing axial movement of an eccentric bearing in a recirculating ball steering gear according to claim 1, characterized in that: The left and right sides of the housing are respectively provided with a first riveting groove and a second riveting groove. The dustproof oil seal on the left side is located in the first riveting groove and is set to abut against the first snap ring. The dustproof oil seal on the output end is located in the second riveting groove and is set to abut against the second snap ring.

3. A structure for reducing axial movement of eccentric bearings in a recirculating ball steering gear according to claim 1, characterized in that: The first baffle is located between the first eccentric bearing and the rocker arm, and the second baffle is located between the second eccentric bearing and the rocker arm.

4. A structure for reducing axial movement of an eccentric bearing in a recirculating ball steering gear according to claim 1, characterized in that: The design and installation method for a structure to reduce axial movement of the eccentric bearing in a recirculating ball steering gear is as follows: a. Grouping the snap rings: Based on the allowable axial clearance and the minimum thickness of the snap ring (determined according to the strength of the snap ring), the snap rings are divided into several groups according to their thickness. The difference in nominal thickness between the middle group and the largest and smallest groups is the allowable clearance. This reduces the tolerance range of the tooth width of the gear sector, the distance from the eccentric bearing flange to the end face of the roller, the thickness of the snap ring, and the distance between the large end faces of the snap ring grooves on both sides. b. Based on the assembly dimension chain of the steering gear rocker arm shaft system shown in the figure (where A - thickness of the first retaining circlip, A' - thickness of the second retaining circlip, B - distance from the flange of the eccentric bearing to the end face of the roller, C - thickness of the retaining plate, D - tooth width of the rocker arm shaft gear sector, E - distance between the large ends of the retaining circlip grooves at both ends, F - allowable axial clearance), first calculate the thickness of the first retaining circlip as the intermediate group, the thickness of the first retaining circlip A, the distance from the flange of the first or second eccentric bearing to the end face of the roller B, and the thickness of the first or second retaining plate. C. The tooth width D of the middle tooth sector of the rocker arm is taken with the upper deviation, and the second circlip groove is the smallest group. When the lower deviation is taken, the distance Emax between the large ends of the two circlip grooves is calculated. Similarly, the thickness A of the first circlip is calculated as the middle group, the distance B from the flange of the first or second eccentric bearing to the end face of the roller is calculated, the thickness C of the first or second baffle is calculated, and the tooth width D of the middle tooth sector of the rocker arm is taken with the lower deviation, and the second circlip groove is the largest group. When the upper deviation is taken, the distance Emin between the large ends of the two circlip grooves is calculated. The design value of dimension E can be determined based on Emax and Emin. c. After fitting the first and second baffles onto both ends of the rocker arm shaft, place it into the housing with the first and second O-rings installed, and install the first and second eccentric bearings with the first and second rocker arm shaft oil seals installed. d. Select the intermediate group for the first retaining ring and install the first retaining ring into the first retaining ring slot. e. Press the flange of the first eccentric bearing against the first retaining ring, and then measure the distance from the flange of the second eccentric bearing to the large end face of the second retaining ring groove. f. Based on the measured distance, select a suitable set of second snap rings and install them into the second snap ring slot. Then, press the second snap ring against the second eccentric bearing to eliminate the axial clearance between the parts of the first and second snap rings. Measure the clearance between the large end face of the second snap ring and the large end face of the second snap ring slot. If the clearance is greater than the allowable axial clearance, increase the size of the second snap ring by one set. g. Synchronously adjust the outer ring phase of the first and second eccentric bearings until the clearance of the gear pair is appropriate; h. Punch the corresponding positions of the flanges of the first eccentric bearing and the second eccentric bearing into the first and second riveting grooves; i. Install the dustproof oil seal on the left side and the dustproof oil seal on the input side.

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