Method for adjusting power steering gear arm shaft clearance with eccentric bearing

Abstract

The application discloses a method for adjusting the clearance between the rocker shafts of a power steering gear by eccentric bearings, and the core of the method is that a mark hole for the maximum eccentricity e and two wrench adjustment circular arc grooves are arranged on the end face of the eccentric bearing, so that the radial clearance of the rocker shafts of the power steering gear can be adjusted by a wrench; when two eccentric bearings are assembled, a snap spring is first installed, then an axial thrust is applied to the outer end of the other eccentric bearing, the axial clearance between all the assembled parts is eliminated, the axial clearance between the outer side of the snap spring groove on the other eccentric bearing and the shell is measured, and another snap spring with a proper thickness is installed according to the axial clearance. The eccentric bearing wrench of the application is easy to be clamped, the clamping claw of the wrench is not easy to be broken, and the assembly and adjustment are relatively convenient; the axial clearance is eliminated by applying an axial thrust, and then another snap spring with a proper thickness is installed, so that the axial clearance of the rocker shafts is ensured to be within the normal tolerance range, and the service life of the power steering gear is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of automotive power steering manufacturing technology, and relates to a method for adjusting the rocker arm shaft clearance of an automotive power steering system using an eccentric bearing. Background Technology

[0002] Recirculating ball power steering systems are widely used in commercial vehicles due to their large output torque and steering angle, high reliability, and long service life. One common method is to use eccentric bearings to adjust the rocker arm shaft clearance.

[0003] Combination Figures 1-4 The diagram illustrates the working principle of existing methods for adjusting rocker arm shaft clearance using eccentric bearings:

[0004] 1) Adjustment of radial clearance of rocker arm shaft

[0005] The gear pair of the recirculating ball power steering system consists of a rocker arm shaft 10 with straight teeth of equal thickness along the tooth width (equal thickness straight teeth) and a rack piston. The radial clearance of the rocker arm shaft is achieved by synchronously adjusting the eccentric bearings 3 at both ends. The eccentric bearings 3 are described in [reference needed]. Figure 2 The outer and inner rings of the eccentric bearing are not concentric, with an eccentricity e. When the inner ring is rotated for adjustment, due to the existence of the eccentricity e, the center of the inner ring of the eccentric bearing moves upward, which reduces the center distance of the gear kinematic pair and thus reduces the radial clearance of the rocker arm shaft. After the adjustment is completed, anti-loosening rivets are punched on the outer edges of the eccentric bearings 3 and 7.

[0006] like Figure 1 As shown in the figure, the wrench adjustment holes of the common eccentric bearing are two holes of different diameters. The large hole is marked as 3-1 and the small hole as 3-2. The position of the largest eccentricity e is also marked. Problems and disadvantages: The different diameters of the round holes make wrench manufacturing and wrench adjustment more difficult, and the smaller diameter of the small hole makes the wrench's pawl more prone to breakage.

[0007] 2) Adjustment of axial clearance of rocker arm shaft

[0008] like Figure 2 , Figure 3 The axial position of the eccentric bearing 3 shown is positioned by the first snap ring 1 and the second snap ring 10 mounted on the housing 11. During assembly, the first snap ring 1 at end A is assembled first, followed by the second snap ring 10 at end B. The resulting axial clearance tolerance between the second snap ring 10 and the outer edge of the snap ring groove in the housing 12 is very large. The cumulative axial clearance tolerance is composed of the thickness tolerances of the first snap ring 1 and the second snap ring 10, the width tolerance of the eccentric bearing 3, the thickness tolerances of the first baffle 4 at end A and the second baffle 6 at end B, the distance tolerance between the outer edges of the two snap ring grooves in the housing 12, and the width tolerance of the rocker arm shaft. When the axial clearance is too large, problems and drawbacks exist:

[0009] The eccentric bearing 3 reciprocates axially, causing wear and damage to the outer circle seals, the first O-ring 5 and the second O-ring 8, resulting in oil leakage. The eccentric bearing 3's axial reciprocating motion also causes the first retaining ring 1 and the second retaining ring 10 to rotate circumferentially, dislodging the first dust seal 2 (see...). Figure 4 The circumferential mounting and positioning flange 2-1 of the first dust seal 2 and the second dust seal 99 are extruded, causing the first dust seal 2 and the second dust seal 99 to fail.

[0010] The eccentric bearing 3 moves back and forth in the axial direction, especially when the rocker arm shaft is subjected to a large lateral force, which causes the anti-loosening point of the eccentric bearing to fail, resulting in uneven meshing of the gear pair, abnormal noise and wear of the gear pair, and a reduction in the service life of the power steering system. Summary of the Invention

[0011] To address the problems of difficulty in adjusting the radial clearance of the rocker arm shaft using a wrench and the easy breakage of the wrench's pawl in existing technologies, as well as the problem of excessive axial clearance of the rocker arm shaft in existing technologies, this invention proposes a method for adjusting the rocker arm shaft clearance of a power steering system using an eccentric bearing.

[0012] Therefore, the technical solution of the present invention is: a method for adjusting the rocker arm shaft clearance of a power steering system using an eccentric bearing, specifically as follows:

[0013] 1) Improvements to eccentric bearings

[0014] A marking hole indicating the maximum eccentricity e is provided on the end face of the eccentric bearing. Two wrench adjustment arc grooves are provided on the end face of the eccentric bearing. The two wrench adjustment arc grooves are arranged in a centrally symmetrical manner, and the outer side of the wrench adjustment arc grooves is open.

[0015] 2) Adjustment of radial clearance of power steering rocker arm shaft

[0016] Use a wrench to adjust the eccentric bearing by inserting it into the wrench adjustment groove and rotating the inner ring. The center of the inner ring of the eccentric bearing will move upward. After adjusting the eccentricity as required, rivet the outer edges of the two eccentric bearings to prevent loosening and ensure the radial clearance of the rocker arm shaft 9 in the assembled state.

[0017] 3) Adjustment of axial clearance of power steering rocker arm shaft

[0018] First, install the first retaining ring, the first eccentric bearing, the sealing ring on the inner hole of the eccentric bearing, the first O-ring on the outer circle of the eccentric bearing, and the first snap ring on the A end of the power steering unit. Then, assemble the second retaining ring, the second eccentric bearing, the sealing ring on the inner hole of the second eccentric bearing, and the second O-ring on the outer circle of the second eccentric bearing on the B end of the power steering unit. Next, apply an axial thrust to the outer end of the second eccentric bearing to eliminate the axial clearance between all assembled parts. Measure the axial clearance between the second eccentric bearing at the B end and the outer side of the snap ring groove on the housing. Select and install a second snap ring of appropriate thickness according to the axial clearance to ensure the axial clearance of the rocker arm shaft.

[0019] Furthermore, the diameter of the marking hole at the maximum position of eccentricity e is no greater than 6 mm, and the radius of the wrench-adjustable arc groove is no less than 8 mm.

[0020] Furthermore, the radial clearance adjustment of the power steering rocker arm shaft is performed after the eccentric bearing is assembled, which makes the adjustment more intuitive and convenient.

[0021] The beneficial effects of this invention are as follows: the eccentric bearing is equipped with two wrench adjustment arc grooves of the same size, which have high strength, making it easy for the wrench to engage when adjusting the radial clearance, and the wrench claws are not prone to breakage, making assembly and adjustment more convenient; the axial clearance between all assembled parts is eliminated by applying axial thrust, and a second retaining spring of appropriate thickness is selected for installation, thereby ensuring that the axial clearance of the rocker arm shaft is within the normal tolerance range, avoiding the failure of the first and second dust seals, preventing oil leakage, and improving the service life of the power steering system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of an existing eccentric bearing.

[0023] Figure 2 This is a front view of the installation of the eccentric bearing and rocker arm shaft in a current power steering system.

[0024] Figure 3 This is a left view of the installation of the eccentric bearing and rocker arm shaft of a current power steering system (with the outermost cap removed).

[0025] Figure 4 yes Figure 3 Enlarged view of section C in the image;

[0026] Figure 5 This is a schematic diagram of the eccentric bearing in this invention;

[0027] Figure 6 This is a front view of the installation of the eccentric bearing and rocker arm shaft of the power steering system of the present invention.

[0028] The figure shows: 1. First retaining ring; 2. First dust seal; 3. Eccentric bearing; 4. First retaining ring; 5. First O-ring; 6. Second retaining ring; 7. Second O-ring; 8. Second dust seal; 9. Rocker arm shaft; 10. Second retaining ring; 11. Housing; 301 Eccentric bearing; 1001 Second retaining ring. Detailed Implementation

[0029] The present invention will now be further described in conjunction with the accompanying drawings and embodiments.

[0030] Example 1

[0031] The improvement of eccentric bearings in this invention: such as Figure 5 As shown, an eccentricity e marking hole 301-1 is provided on the end face of the eccentric bearing 301, and two wrench adjustment arc grooves 301-2 are provided on the end face of the eccentric bearing. The two wrench adjustment arc grooves are centrally symmetrically arranged, and the outer side of the wrench adjustment arc grooves 301-2 is open. The presence of two wrench adjustment arc grooves provides high strength, makes it easy for the wrench to be inserted, and the wrench's pawl is not easy to break, making assembly and adjustment convenient.

[0032] In optimized embodiment 1, the diameter of the marking hole 301-1 at the maximum position of eccentricity e is no greater than 6 mm, and the radius of the wrench adjustment arc groove is no less than 8 mm. With this size setting, the marking hole 301-1 at the maximum position of eccentricity e is sufficient to meet the requirements, and it is easier to insert the wrench when adjusting it, further ensuring that the wrench's pawl is not easy to break.

[0033] Example 2

[0034] Combination Figure 6 As shown, the method for adjusting the rocker arm shaft clearance of the power steering system using the eccentric bearing of Example 1 is as follows:

[0035] 1) Adjustment of radial clearance of power steering rocker arm shaft

[0036] In the non-assembled state, use a wrench to lock in the wrench adjustment arc groove 301-2 of the eccentric bearing 301, rotate the inner ring to adjust, and the center of the inner ring of the eccentric bearing will move upward. After adjusting the eccentricity as required, rivet the outer edges of the two eccentric bearings 301 to prevent loosening; thus, in the assembled state, the radial clearance of the rocker arm shaft 9 is guaranteed.

[0037] 2) Adjustment of axial clearance of power steering rocker arm shaft

[0038] First, install the first retaining ring 4, the first eccentric bearing 301, the sealing ring on the inner hole of the eccentric bearing, the first O-ring 5 on the outer circle of the eccentric bearing, and the first snap ring 1 at end A of the power steering gear. Then, install the second retaining ring 6, the second eccentric bearing 301, the sealing ring on the inner hole of the second eccentric bearing, and the second O-ring 7 on the outer circle of the second eccentric bearing at end B of the power steering gear. Then, apply an axial thrust F to the outer end of the second eccentric bearing to eliminate the axial clearance between all the assembled parts (two eccentric bearings 301, the second retaining ring 6, the rocker arm shaft 10, the first retaining ring 4, the first snap ring 1, and the snap ring groove at end B of the housing 11). Measure the axial clearance between the second eccentric bearing at end B and the outer side of the snap ring groove on the housing. Select a second snap ring 1001 of appropriate thickness according to the axial clearance and install it on the housing 11. Finally, install the first dust seal 2, the second dust seal 8, and the outermost (both ends) plugs of the housing to ensure the axial clearance of the rocker arm shaft.

[0039] Example 3

[0040] The difference from Embodiment 2 is that: first, the axial clearance of the power steering rocker arm shaft is adjusted, and then the eccentricity of the eccentric bearing 301 is adjusted with a wrench in the assembled state to ensure the radial clearance of the rocker arm shaft 9.

[0041] In this invention, "radial clearance adjustment of power steering rocker arm shaft" and "axial clearance adjustment of power steering rocker arm shaft" are two steps of clearance adjustment. Steps 1) and 2) in Example 2 are only for clearly distinguishing different steps and do not represent a strict sequence of steps.

[0042] The above description is merely a preferred embodiment of the present invention. Any equivalent substitutions or modifications made by those skilled in the art based on the concept of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for adjusting the clearance of a power steering rocker arm shaft using an eccentric bearing, characterized in that, Specifically: 1) Improvements to eccentric bearings A marking hole indicating the maximum eccentricity e is provided on the end face of the eccentric bearing. Two wrench adjustment arc grooves are provided on the end face of the eccentric bearing. The two wrench adjustment arc grooves are arranged in a centrally symmetrical manner, and the outer side of the wrench adjustment arc grooves is open. 2) Adjustment of radial clearance of power steering rocker arm shaft Use a wrench to fit in the wrench adjustment arc groove of the eccentric bearing, rotate the inner ring to adjust, the center of the inner ring of the eccentric bearing moves up, adjust the eccentricity according to the requirements, after the adjustment is completed, rivet the outer edges of the two eccentric bearings to prevent loosening, and ensure the radial clearance of the rocker arm shaft (9) in the assembled state. 3) Adjustment of axial clearance of power steering rocker arm shaft First, install the first retaining ring, the first eccentric bearing, the sealing ring on the inner hole of the eccentric bearing, the first O-ring on the outer circle of the eccentric bearing, and the first snap ring on the A end of the power steering unit. Then, assemble the second retaining ring, the second eccentric bearing, the sealing ring on the inner hole of the second eccentric bearing, and the second O-ring on the outer circle of the second eccentric bearing on the B end of the power steering unit. Next, apply an axial thrust to the outer end of the second eccentric bearing to eliminate the axial clearance between all assembled parts. Measure the axial clearance between the second eccentric bearing at the B end and the outer side of the snap ring groove on the housing. Select and install a second snap ring of appropriate thickness according to the axial clearance to ensure the axial clearance of the rocker arm shaft.

2. The method for adjusting the rocker arm shaft clearance of a power steering system using an eccentric bearing according to claim 1, characterized in that, When the eccentricity e is at its maximum position, the diameter of the marking hole should not exceed 6 mm, and the diameter of the wrench adjustment arc groove should not be less than 8 mm.

3. The method for adjusting the rocker arm shaft clearance of a power steering system using an eccentric bearing according to claim 1, characterized in that, The radial clearance adjustment of the power steering rocker arm shaft is performed after the eccentric bearing is assembled.

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