Electric steering gear spindle worm gear assembly tooling and press-fitting method

Abstract

This invention discloses an assembly fixture for an electric steering gear main shaft worm gear assembly, including a moving mechanism for sequentially pressing the worm gear assembly and the worm gear torsion bar assembly, and a right-side positioning pressing mechanism for pressing the torsion bar and worm gear assembly, and a left-side positioning pressing mechanism for pressing the input shaft and the worm gear torsion bar assembly, respectively positioned on the left and right positioning holes of the moving base of the moving mechanism. This electric steering gear main shaft worm gear assembly assembly fixture solves problems such as excessive radial and end face runout and deformation during worm gear pressing on the main shaft assembly, difficulties in pressing the main shaft worm gear assembly, and inconsistent pressing force identification requirements. It achieves fast and accurate angular positioning and high pressing efficiency during the pressing of the main shaft worm gear assembly; it can also achieve sequential identification of the pressing force during the pressing process of the torsion bar and input shaft, improving product process quality. This invention also discloses a method for pressing the electric steering gear main shaft worm gear assembly.

Description

Technical Field

[0001] This invention belongs to the technical field of vehicle steering systems. Specifically, this invention relates to an assembly fixture and pressing method for an electric steering gear main shaft worm gear assembly. Background Technology

[0002] The existing spindle assembly consists of an input shaft, a torsion bar, and a gear shaft. After the spindle assembly is press-fitted, a worm gear needs to be press-fitted onto the gear shaft diameter. The problems with this press-fitting process are as follows:

[0003] 1. When the worm gear with the tooth profile is pressed onto the gear shaft, it is easy to cause the radial runout and end face runout of each tooth profile of the worm gear to exceed the tolerance. The radial runout when the worm rotates increases, which increases the mechanical fluctuation of the steering gear, resulting in an uneven feel, vibration and abnormal noise, and a poor driving experience.

[0004] 2. The structure with the worm gear assembled on the gear shaft. Due to the large diameter of the worm gear, the angular positioning method of aligning the gear shaft and the input shaft ±5° flat square cannot be used for positioning and assembly on the existing spindle press-fitting fixture.

[0005] 3. The pressing force requirements for the torsion bar on the existing spindle assembly when pressing into the gear shaft and the input shaft are different. The pressing is done in the same pressing process by changing the pressure sleeve. It is not possible to separately identify whether the pressing force of the torsion bar and the input shaft is within the required range. At the same time, the pressing efficiency is low.

[0006] This invention provides an assembly fixture and press-fitting method for the main shaft worm gear assembly of an electric steering gear, particularly concerning how to improve the angular positioning efficiency and accuracy during the press-fitting of the main shaft worm gear assembly. Summary of the Invention

[0007] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides an assembly fixture for the main shaft worm gear assembly of an electric steering system, with the purpose of improving the angular positioning efficiency and accuracy during the press-fitting of the main shaft worm gear assembly.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an electric steering gear main shaft worm gear assembly assembly fixture, including a moving mechanism for sequentially pressing the worm gear assembly and the worm gear torsion bar assembly, and a right-side positioning pressing mechanism for pressing the torsion bar and the worm gear assembly and a left-side positioning pressing mechanism for pressing the input shaft and the worm gear torsion bar assembly, respectively positioned on the left and right positioning holes of the moving base of the moving mechanism.

[0009] The moving mechanism includes a transition base plate, a first slider guide rail assembly, a second slider guide rail assembly, and a rodless cylinder disposed on the transition base plate. A moving base is slidably disposed on the first slider guide rail assembly and the second slider guide rail assembly. The rodless cylinder is configured to control the moving base to switch between a first position and a second position. The right positioning and pressing mechanism and the left positioning and pressing mechanism are disposed on the moving base.

[0010] The rodless cylinder is connected to the movable base via an L-shaped connecting block. The first slider guide rail assembly and the second slider guide rail assembly include multiple sliders. The movable base is connected to the sliders. The right-side positioning and pressing mechanism and the left-side positioning and pressing mechanism are fixed on the movable base.

[0011] The right-side positioning and pressing mechanism includes a first base, a first positioning sleeve on the first base, a positioning guide sleeve above the first positioning sleeve, a guide pressure sleeve on the positioning guide sleeve, a transition guide pressure sleeve inside the guide pressure sleeve, and a pressure head that cooperates with a servo press above the guide pressure sleeve.

[0012] The first positioning sleeve is a hollow shaft component. Its outer end shaft diameter is clearance-fitted with the countersunk hole of the first base. An annular groove is provided in the middle. The first positioning sleeve is positioned on the first base by bolts. The first positioning sleeve has a through hole in the axial direction for positioning with clearance-fitted with the shaft diameter of the worm gear assembly, and its length is greater than the depth of the countersunk hole of the first base.

[0013] The positioning guide sleeve is a stepped shaft component. The upper end of the large end shaft diameter is provided with a first countersunk hole for positioning with a clearance fit with the outer diameter of the guide sleeve, and a through hole for accommodating the torsion bar is provided in the middle. The lower end of the small end shaft diameter is provided with a second countersunk hole for positioning with a clearance fit with the upper end shaft diameter of the worm gear assembly.

[0014] The left-side positioning and pressing mechanism includes a second base, a second positioning sleeve on the second base, a U-shaped guide sleeve above the second positioning sleeve, a pressing sleeve inside the U-shaped guide sleeve, a guide block and a limiting block on the pressing sleeve, and a locking handle on the pressing sleeve.

[0015] The U-shaped guide sleeve is a hollow component. The upper end is provided with a first countersunk hole that is clearance-fitted with the outer diameter of the pressure sleeve. The first countersunk hole is provided with a U-shaped groove in the radial direction that is clearance-fitted with the width dimension of the guide block. The lower end is provided with a second countersunk hole that is clearance-fitted with the upper diameter of the worm gear torsion bar assembly. Two arc-shaped positioning blocks are provided between the first countersunk hole and the second countersunk hole that are in sync with the groove on the worm gear torsion bar assembly.

[0016] The limiting block is provided with a V-shaped groove for positioning the input shaft, and the inside of the V-shaped groove is provided with an arc surface that avoids the diameter of the input shaft.

[0017] The present invention also provides a method for press-fitting an electric steering gear main shaft worm gear assembly, using the aforementioned electric steering gear main shaft worm gear assembly assembly fixture, comprising the following steps:

[0018] S1. Position the worm gear assembly in the first positioning sleeve and place the movable base in the first position;

[0019] S2. Place the torsion bar positioning device in the inner hole of the worm gear assembly;

[0020] S3. The pressure tapping sleeve assembly is fitted onto the upper end of the torsion bar, the inner hole of the transition guide sleeve is positioned on the spline at the upper end of the torsion bar, and the countersunk hole at the lower end of the positioning guide sleeve is positioned on the upper shaft diameter of the worm gear assembly.

[0021] S4. Start the servo press. The servo press pushes the press head down to the upper end face of the guide sleeve. It then moves down through the guide sleeve and the transition guide sleeve to push the torsion bar down into the inner hole of the worm gear assembly. This continues until the end face of the guide sleeve is in contact with the bottom surface of the countersunk hole at the upper end of the positioning guide sleeve. This completes the press-fitting of the torsion bar and the worm gear assembly, forming the worm gear torsion bar assembly. At this point, after the press head moves up to the starting position, the moving base moves to the second position.

[0022] S5. Remove the worm gear torsion bar assembly from the first positioning sleeve, and then put the worm gear torsion bar assembly into the second positioning sleeve;

[0023] S6. Place the U-shaped guide sleeve onto the worm gear torsion bar assembly, and position the two arc-shaped positioning blocks on the U-shaped guide sleeve by matching the grooves on the worm gear torsion bar assembly.

[0024] S7. Take the input shaft and install it into the pressure sleeve. Then take the limit block to position the input shaft. Tighten the locking handle to fix the input shaft in the pressure sleeve. Then remove the limit block and align the guide block with the U-shaped groove on the U-shaped guide sleeve. Place the guide block into the U-shaped guide sleeve.

[0025] S8. Restart the servo press. The servo press pushes the press head down to the upper end face of the press sleeve. Then, it pushes the upper inner hole of the input shaft down to the upper spline of the torsion bar through the press sleeve until the end face of the press sleeve is in contact with the bottom surface of the countersunk hole at the upper end of the U-shaped guide sleeve. This completes the press-fitting of the input shaft and the worm gear torsion bar assembly, forming the main shaft worm gear assembly. After the press head moves up to the starting position, the moving base moves to the first position.

[0026] S9. Loosen the locking handle and remove the pressure sleeve, U-shaped guide sleeve and spindle worm gear assembly in sequence. At this point, the entire process of pressing the spindle worm gear assembly is completed.

[0027] The electric steering gear main shaft worm gear assembly assembly fixture of the present invention solves the problems of excessive radial and end face runout and deformation when the worm gear is pressed onto the main shaft assembly, as well as the difficulties in assembling and pressing the main shaft worm gear assembly and the inconsistent requirements for pressing force identification. It achieves fast and accurate angle positioning and high pressing efficiency during the pressing of the main shaft worm gear assembly; it can also realize the sequential identification of the pressing force during the pressing process of the torsion bar and input shaft, thereby improving the quality of the product process. Attached Figure Description

[0028] This manual includes the following figures, which illustrate the following:

[0029] Figure 1 This is a schematic diagram of the press-fitting method of the automotive steering gear main shaft worm gear assembly of the present invention;

[0030] Figure 2 This is an exploded view of the input shaft, torsion bar, and worm gear assembly.

[0031] Figure 3 This is a sectional view of the spindle worm gear assembly;

[0032] Figure 4 yes Figure 3 Sectional view of AA;

[0033] Figure 5 This is an exploded view of the assembly of the positioning tooling parts for the spindle worm gear assembly;

[0034] Figure 6 This is the front view of the spindle worm gear assembly press-fit fixture;

[0035] Figure 7 yes Figure 6 BB cross-sectional view when the rodless cylinder is placed on the left side and the torsion bar is press-fitted;

[0036] Figure 8 yes Figure 6 BB section view when the rodless cylinder is placed on the right side press-fitted input shaft;

[0037] Figure 9 yes Figure 6 A partial sectional view of BB;

[0038] Figure 10 yes Figure 7 A partial sectional view of CC;

[0039] Figure 11 yes Figure 7 A partial sectional view of DD;

[0040] Figure 12 This is a schematic diagram of the shaft side of the shaft insertion and positioning block assembly;

[0041] Figure 13 This is a schematic diagram of the shaft side of the pressure sleeve;

[0042] Figure 14 This is a schematic diagram of the guide block's axial side;

[0043] Figure 15 This is a schematic diagram of the U-shaped guide sleeve shaft side;

[0044] Figure 16 This is the main view of the U-shaped guide sleeve;

[0045] Figure 17 This is a schematic diagram of the isometric side of the limiting block;

[0046] Figure 18 This is the main view of the limit block;

[0047] The markings in the diagram are as follows: 1. First T-shaped slider; 2. Second T-shaped slider; 3. First bolt; 4. Second bolt; 5. First base; 6. Third bolt; 7. First positioning sleeve; 801. Worm gear assembly; 802. Gear shaft; 803. Worm gear ring; 804. Worm gear core; 9. Torsion bar; 10. Positioning guide sleeve; 11. Transition guide pressure sleeve; 12. Fourth bolt; 13. Fifth bolt; 14. Guide pressure sleeve; 15. Sixth bolt; 16. Pressure head; 17. Pressure sleeve; 18. Guide block; 19. First positioning pin; 20. Second positioning pin; 21. Locking handle; 22. Limit block; 23. Input shaft ; 24. U-shaped guide sleeve; 25. Worm gear torsion bar assembly; 26. Second positioning sleeve; 27. Second base; 28. Seventh bolt; 29. ​​Eighth bolt; 30. Ninth bolt; 31. Third T-shaped slider; 32. Fourth T-shaped slider; 33. Moving base; 34. First slider guide rail assembly; 3401. First slider; 3402. Second slider; 3403. First guide rail; 35. Transition base plate; 36. L-shaped connecting block; 37. Rodless cylinder; 38. Second slider guide rail assembly; 3801. Third slider; 3802. Fourth slider; 3803. Second guide rail; 39. Servo press. Detailed Implementation

[0048] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.

[0049] It should be noted that in the following embodiments, the terms "first", "second", "third" and "fourth" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution, but are merely for the convenience of description.

[0050] like Figures 1 to 18As shown, the present invention provides an assembly fixture for an electric steering gear main shaft worm gear assembly, including a moving mechanism for sequentially pressing the worm gear assembly and the worm gear torsion bar assembly, and a right-side positioning pressing mechanism for pressing the torsion bar and the worm gear assembly and a left-side positioning pressing mechanism for pressing the input shaft and the worm gear torsion bar assembly, respectively positioned on the left and right positioning holes of the moving base of the moving mechanism.

[0051] Specifically, this invention provides an assembly fixture and press-fitting method for an electric steering gear main shaft worm gear assembly. It optimizes existing worm gear machining and press-fitting processes by using a modified worm gear assembly structure, whose components include a gear shaft, a worm gear core, and a worm gear ring. Before assembly, a semi-finished worm gear is press-fitted onto the gear shaft diameter. Then, the worm gear surface tooth profile on the worm gear assembly is precision machined. The machining equipment ensures the accuracy of the worm gear surface tooth profile. After assembly, the worm gear and gear shaft form the worm gear assembly.

[0052] The electric steering gear main shaft worm gear assembly assembly fixture provided by this invention solves problems such as excessive radial and end face runout and deformation of the worm gear during press-fitting onto the main shaft assembly, as well as difficulties in press-fitting the main shaft worm gear assembly and inconsistent press-fitting force identification requirements. Its purpose is to ensure the tooth profile accuracy of the worm gear surface and to achieve fast and accurate angular positioning during press-fitting of the main shaft worm gear assembly, resulting in high press-fitting efficiency. Sequential identification of the press-fitting force during the press-fitting process of the torsion bar and input shaft further improves product process quality.

[0053] like Figure 1 , Figures 5 to 11As shown, the moving mechanism includes a first T-shaped slider 1, a second T-shaped slider 2, a first bolt 3, a second bolt 4, an eighth bolt 29, a ninth bolt 30, a third T-shaped slider 31, a fourth T-shaped slider 32, a moving base 33, a first slider guide rail assembly 34, a transition base plate 35, an L-shaped connecting block 36, a rodless cylinder 37, and a second slider guide rail assembly 38. The transition base plate 35 is fastened to the servo press 39 by four hexagon socket head cap screws. The upper end face of the transition base plate 35 has countersunk holes for the hexagon socket head cap screws to pass through. The upper end face of the transition base plate 35 has threaded holes in the first horizontal direction and the second horizontal direction for fastening the first slider guide rail assembly 24 and the second slider guide rail assembly 38 with eight hexagon socket head cap screws. The upper end face of the transition base plate 35 has threaded holes in the first horizontal direction and the second horizontal direction for fastening the rodless cylinder 37 with four hexagon socket head cap screws. The rodless cylinder 37 is mounted on the transition base plate 35. The first slider guide rail assembly 34 and the second slider guide rail assembly 38 are both assemblies with identical dimensions and structures. The first slider guide rail assembly 34 includes a first slider 3401, a second slider 3402, and a first guide rail 3403. The second slider guide rail assembly 38 includes a third slider 3801, a fourth slider 3802, and a second guide rail 3803. The first slider 3401 and the second slider 3402 can move freely horizontally on the first guide rail 3403. The third slider 3801 and the fourth slider 3802 can move freely horizontally on the second guide rail 3803. The length directions of the first guide rail 3403 and the second guide rail 3803 are parallel. The upper ends of the first guide rail 3403 and the second guide rail 3803 are respectively provided with eight countersunk holes for assembly with hexagon socket head cap screws on the transition base plate 35. The upper surfaces of the first slider 3401, the second slider 3402, the third slider 3801, and the fourth slider 3802 are provided with four threaded holes for fastening with hexagon socket head cap screws to the countersunk holes on the upper end of the movable base 33.

[0054] The rodless cylinder 37 has four threaded holes at its upper end for assembly and positioning with the L-shaped connecting block 36. The left and right ends of the rodless cylinder 37 have four countersunk holes for mounting four hexagon socket head cap bolts on the upper surface of the transition base plate 35. The rodless cylinder 37 is horizontally assembled and positioned between the first slider guide assembly 34 and the second slider guide assembly 38, and the extension / retraction direction of the rodless cylinder 37 is parallel to the length direction of the first guide rail 3403 and the second guide rail 3803.

[0055] The horizontal end face of the L-shaped connecting block 36 has four positioning through holes for fastening to the rodless cylinder 37 with hexagon socket head cap screws. The vertical end face has four positioning through holes for fastening to the left side of the movable base 33. The upper end face of the movable base 33 has eight countersunk holes for fastening to the upper end faces of the first slider 3401, the second slider 3402, the third slider 3801, and the fourth slider 3802 with hexagon socket head cap screws.

[0056] The upper surface of the movable base 33 has two T-shaped grooves for accommodating the first T-shaped slider 1, the second T-shaped slider 2, the third T-shaped slider 31, and the fourth T-shaped slider 32. These grooves are located between the two sets of countersunk holes for mounting the first slider 3401 and the third slider 3801 and the second slider 3402 and the fourth slider 38, and are perpendicular to the horizontal direction of the first slider guide rail assembly 34 and the second slider guide rail assembly 38. At the same time, a positioning through hole is provided between the two T-shaped grooves for positioning the lower end shaft diameter clearance fit of the first base 5 and the second base 27.

[0057] The left end face of the movable base 33 has four internally threaded holes for fastening with hexagonal socket bolts on the vertical end face of the L-shaped connecting block 36. By controlling the air intake direction of the rodless cylinder 37, the rodless cylinder 37 drives the L-shaped connecting block 36 and the movable base 33 to move linearly along the length direction of the first guide rail 3403 and the second guide rail 3803. The movable base 33 drives the left positioning and pressing mechanism and the right positioning and pressing mechanism to move linearly synchronously, thereby realizing position adjustment.

[0058] The first T-shaped slider 1, the second T-shaped slider 2, the third T-shaped slider 31, and the fourth T-shaped slider 32 are components with the same structural dimensions, and are provided with threaded holes in the middle for screwing and fastening with the first bolt 3, the second bolt 4, the eighth bolt 29, and the ninth bolt 30. The first T-shaped slider 1, the second T-shaped slider 2, the third T-shaped slider 31, and the fourth T-shaped slider 32 are respectively placed in two T-shaped slots on the movable base 33 and are fastened and fixed in place by the first bolt 3, the second bolt 4, the eighth bolt 29, and the ninth bolt 30. The first base 5 and the second base 27 are placed on the movable base 33.

[0059] like Figure 1 , Figures 5 to 11 As shown, the positioning and pressing mechanism on the right includes a first base 5, a third bolt 6, a first positioning sleeve 7, a positioning guide sleeve 10, a transition guide pressure sleeve 11, a fourth bolt 12, a fifth bolt 13, a guide pressure sleeve 14, a sixth bolt 15, and a pressure head 16. The first base 5 and the second base 27 are hollow shaft-type components with the same structural dimensions.

[0060] The lower ends of the first base 5 and the second base 27 are provided with small-end shaft diameters for clearance fit positioning with the movable base 33. A large-end shaft diameter is provided in the middle of the first base 5 and the second base 27. The end face of the large-end shaft diameter of the first base 5 is limited by the end face of the movable base 33 and has through holes for assembling the first bolt 3 and the second bolt 4. The end face of the large-end shaft diameter of the second base 27 is limited by the end face of the movable base 33 and has through holes for assembling the eighth bolt 29 and the ninth bolt 30. The upper end face of the large-end shaft diameter of the first base 5 has a countersunk hole for clearance fit with the shaft diameter of the first positioning sleeve 7. The upper end face of the large-end shaft diameter of the second base 27 has a countersunk hole for clearance fit with the shaft diameter of the second positioning sleeve 26.

[0061] The first base 5 has a threaded hole perpendicular to the radial direction of the shaft diameter for assembling the third bolt 6. The first positioning sleeve 7 is positioned on the first base 5 by tightening the third bolt 6 in the annular groove in the middle of the first positioning sleeve 7. The second base 27 has a threaded hole perpendicular to the radial direction of the shaft diameter for assembling the seventh bolt 28. The second positioning sleeve 26 is positioned on the second base 27 by tightening the seventh bolt 28 in the annular groove in the middle of the second positioning sleeve 26.

[0062] like Figure 1 , Figures 5 to 11 As shown, the first positioning sleeve 7 and the second positioning sleeve 26 are hollow shaft-type components with the same structural dimensions. The outer end of the shaft diameter is clearance-fitted with the countersunk holes of the first base 5 and the second base 27. A positioning annular groove is provided in the middle. By loosening the third bolt 6 and the seventh bolt 28 and positioning them in the annular groove between the first positioning sleeve 7 and the second positioning sleeve 26, positioning sleeves with different shaft diameters can be quickly changed. The first positioning sleeve 7 has a through hole in the axial direction for clearance-fitting positioning with the shaft diameter of the worm gear assembly 801. Its length is greater than the countersunk hole depth of the first base 5, used to prevent interference between the lower end face of the worm gear assembly 801 and the upper end face of the first base 5. This ensures that the lower end face of the worm gear assembly 801 is in close contact with the upper end face of the first positioning sleeve 7 under stress, preventing the worm gear from deforming during the press-fitting process. The second positioning sleeve 26 has a through hole in the axial direction for clearance-fitting positioning with the shaft diameter of the worm gear torsion bar assembly 25. Its length is greater than the countersunk hole depth of the second base 27, used to prevent interference between the lower end face of the worm gear torsion bar assembly 25 and the upper end face of the second base 27. Ensure that the lower end face of the worm gear torsion bar assembly 25 is in contact with the upper end face of the second positioning sleeve 26 to prevent the worm gear from deforming during the press-fitting process.

[0063] like Figure 1 , Figures 5 to 11As shown, the positioning guide sleeve 10 is a stepped shaft component. The upper end face of the large end of the positioning guide sleeve 10 has a first countersunk hole for positioning with a clearance fit to the outer diameter of the guide sleeve 14. The middle of the positioning guide sleeve 10 has a through hole to accommodate the torsion bar 9. The lower end of the small end of the positioning guide sleeve 10 has a second countersunk hole for positioning with a clearance fit to the upper end of the worm gear assembly 801. The first and second countersunk holes are on the same axis. A waist-shaped groove is provided in the radial direction of the large end of the positioning guide sleeve 10 to accommodate the fourth bolt 12 and the fifth bolt 13. The positioning guide sleeve 10 is tightly fixed in place by the threaded holes in the radial direction of the guide sleeve 14 through the fourth bolt 12 and the fifth bolt 13. The guide sleeve 14 can move up and down within the waist-shaped groove on the positioning guide sleeve 10, while ensuring the coaxiality of the torsion bar 9 and the worm gear assembly 801 during press-fitting. The outer diameter of the transition guide sleeve 11 has a clearance fit with the countersunk hole at the lower end of the guide sleeve 14. The lower end of the transition guide sleeve 11 is provided with a first countersunk hole that is clearance-fitted to the outer diameter of the spline at the upper end of the torsion bar 9. The upper end of the transition guide sleeve 11 is provided with a threaded hole that is fastened together with the second countersunk hole at the upper end of the guide sleeve 14 and the sixth bolt 15. By changing the countersunk hole of different depths at the lower end of the transition guide sleeve 11, the pressing position of the torsion bar 9 on the worm gear assembly 801 can be met.

[0064] The outer diameter of the guide sleeve 14 is clearance-fitted with the first countersunk hole of the positioning guide sleeve 10. The lower end of the guide sleeve 14 has a first countersunk hole that is clearance-fitted with the outer diameter of the transition guide sleeve 11. The upper end of the guide sleeve 14 has a second countersunk hole for assembling the sixth bolt 15. The first and second countersunk holes are coaxial with the outer diameter.

[0065] The pressure head 16 is a hollow shaft component that is smaller at the top and larger at the bottom. The small end of the pressure head 16 is clearance-fitted with the transition sleeve hole at the upper end of the servo press 39. An annular groove for bolt limiting and fastening is provided in the middle of the small end of the pressure head 16.

[0066] like Figure 5 , Figures 7 to 18 As shown, the left-side positioning and pressing mechanism includes a pressure sleeve 17, a guide block 18, a first positioning pin 19, a second positioning pin 20, a locking handle 21, a limit block 22, a U-shaped guide sleeve 24, a second positioning sleeve 26, a second base 27, and a seventh bolt 28.

[0067] The pressure sleeve 17 is a hollow shaft component. The outer diameter of the pressure sleeve 17 is clearance-fitted with the countersunk hole at the upper end of the U-shaped guide sleeve 24. The lower end of the pressure sleeve 17 is provided with a countersunk hole on the same axis as the axis to accommodate the input shaft 23 and to fit with the smaller diameter sections of the input shaft 23. The diameter of the first countersunk hole at the lower end of the pressure sleeve 17 is larger than the diameter of the second countersunk hole, and the diameter of the second countersunk hole is larger than the diameter of the third countersunk hole. The third countersunk hole, the second countersunk hole, and the first countersunk hole are arranged axially at the center of the pressure sleeve 17 and are connected to each other. The end face of the first countersunk hole is provided with a positioning groove that is perpendicular to the axis of the pressure sleeve 17 and to fit with the smaller width dimension of the limiting block 22. The depth of the positioning groove is the same as the depth of the first countersunk hole. In the radial direction of the middle of the second countersunk hole and parallel to the center line of the positioning groove, there is a threaded hole for engaging with the external thread on the locking handle 21, and two positioning pin holes for interference fit with the first positioning pin 19 and the second positioning pin 20.

[0068] The guide block 18 is a C-shaped flat key component. The guide block 18 has an R-angle arc surface that mates with the outer diameter of the pressure sleeve 17. Two locating pin holes, perpendicular to the end face and extending to the arc surface, are provided for interference fit with the first locating pin 19 and the second locating pin 20, and a through hole is provided to accommodate the external thread on the locking handle 21. The spacing between the two locating pin holes and the position of the through hole are consistent with the spacing between the two locating pin holes and the position of the threaded holes on the pressure sleeve 17. The guide block 18 and the pressure sleeve 17 are fastened together by the interference fit between the first locating pin 19 and the second locating pin 20 and the locating holes. The width of the guide block 18 has a small clearance fit with the U-shaped groove at the upper end of the U-shaped guide sleeve 24, ensuring that the pressure sleeve 17 can only move up and down within the U-shaped guide sleeve 24, and cannot rotate circumferentially. During press-fitting, the input shaft 23 is pressed down at a stable angle with the worm gear torsion bar assembly.

[0069] The locking handle 21 is a stepped shaft component. The outer diameter of the large end of the locking handle 21 is knurled for easy gripping and rotation by the operator. The middle diameter of the locking handle 21 has an external thread for engaging with the internal threaded hole on the pressure sleeve 17. The small end of the locking handle 21 is located at the front end of the external thread. Rotating the locking handle 21 causes the end face of the small end of the shaft to press the outer diameter of the input shaft 23 onto the pressure sleeve 17.

[0070] The input shaft 23 has a V-shaped flattened structure at its end, with the center line of symmetry of the V-shaped flattened structure having an angular deviation of ±5° relative to the axis of the input shaft. The limiting block 22 is a rectangular block structure. The front end of the limiting block 22 has a V-shaped groove with an angle consistent with the V-shaped flattened structure of the input shaft 23, and the bottom of the V-shaped groove has an arc surface that avoids the diameter of the input shaft 23. Both ends of the limiting block 22 have notches that avoid the end face of the V-shaped flattened structure of the input shaft 23. The width of the limiting block 22 is fitted with a small clearance to the positioning groove on the pressure sleeve 17. This ensures accurate angular positioning of the V-shaped flattened structure of the input shaft 23 through the V-shaped groove on the limiting block 22 and the positioning groove on the pressure sleeve 17.

[0071] The bottom of the V-groove has an arc surface that avoids contact with the shaft diameter of the input shaft 23. Its main function is to prevent contact interference between the bottom of the limiting block 22 and the shaft diameter surface of the input shaft 23 when the V-shaped flat surface of the input shaft 23 is angularly positioned by the limiting block. This ensures precise engagement between the V-groove on the limiting block 22 and the V-shaped flat surface of the input shaft 23, achieving reliable angular positioning and guaranteeing the angular alignment accuracy of the input shaft 23 and the worm gear torsion bar assembly during press-fitting. It also prevents the limiting block 22 from squeezing or wearing the shaft diameter of the input shaft 23, ensuring the structural integrity of the input shaft 23. Furthermore, it avoids contact interference affecting the stability and accuracy of the press-fitting process, thus improving press-fitting quality and efficiency.

[0072] The U-shaped guide sleeve 24 is a hollow component. The upper end of the U-shaped guide sleeve 24 has a first countersunk hole that fits with the outer diameter of the pressure sleeve 17. On the U-shaped guide sleeve 24, a U-shaped groove is formed in the radial direction of the first countersunk hole, perpendicular to the axis and with a small clearance fit to the width of the guide block 18. The lower end of the U-shaped guide sleeve 24 has a second countersunk hole in the same axial direction as the axis, which fits with the upper diameter of the worm gear torsion bar assembly 25 with a small clearance. On the U-shaped guide sleeve 24, two arc-shaped positioning blocks are provided between the first and second countersunk holes, which fit with the upper diameter of the worm gear torsion bar assembly 25 with a small clearance. The two arc-shaped positioning blocks are positioned within the grooves on the worm gear torsion bar assembly 25. The U-shaped guide sleeve 24, guide block 18, limiting block 22, and locking handle 21 precisely press-fit the V-shaped flat bar on the input shaft 23, positioned within the pressure sleeve 17, with the groove on the worm gear torsion bar assembly 25 at a precise axial angle.

[0073] The present invention also provides a method for press-fitting an electric steering gear main shaft worm gear assembly, using an electric steering gear main shaft worm gear assembly assembly tooling with the above-described structure, comprising the following steps:

[0074] S1. Position the worm gear assembly 801 in the first positioning sleeve 7 and place the movable base 33 in the first position;

[0075] S2. Position the torsion bar 9 in the inner hole of the worm gear assembly 801;

[0076] S3. The pressure-taking sleeve assembly is fitted onto the upper end of the torsion bar 9. The inner hole of the transition guide sleeve 11 is positioned on the spline at the upper end of the torsion bar 9. The countersunk hole at the lower end of the positioning guide sleeve 10 is positioned on the upper shaft diameter of the worm gear assembly 801.

[0077] S4. Start the servo press 39. The servo press 39 pushes the press head 16 down to the upper end face of the guide sleeve 14. Then it moves down through the guide sleeve 14 and the transition guide sleeve 11 to push the torsion bar 9 down into the inner hole of the worm gear assembly 801 until the end face of the guide sleeve 14 is in contact with the bottom surface of the upper countersunk hole of the positioning guide sleeve 10. That is, the press-fitting of the torsion bar 9 and the worm gear assembly 801 is completed, forming the worm gear torsion bar assembly 25. At this time, after the press head 16 moves up to the starting position, the moving base 33 moves to the second position.

[0078] S5. Remove the worm gear torsion bar assembly 25 from the first positioning sleeve 7, and then put the worm gear torsion bar assembly 25 into the second positioning sleeve 26.

[0079] S6. Take the U-shaped guide sleeve 24 and install it on the worm gear torsion bar assembly 25. The two arc-shaped positioning blocks on the U-shaped guide sleeve 24 are matched with the grooves on the worm gear torsion bar assembly 25 for positioning.

[0080] S7. Take the input shaft 23 and install it into the pressure sleeve 17. Then take the limit block 22 to position the input shaft 23. Then tighten the locking handle 21 to fix the input shaft 23 in the pressure sleeve 17. Then remove the limit block 22. Then align the guide block 18 with the U-shaped groove on the U-shaped guide sleeve 24 and put the guide block 18 into the U-shaped guide sleeve 24.

[0081] S8. Restart the servo press 39. The servo press 39 pushes the press head 16 down to the upper end face of the press sleeve 17. It then pushes the upper inner hole of the input shaft 23 down to the upper spline of the torsion bar 9 through the press sleeve 17 until the end face of the press sleeve 17 is in contact with the bottom surface of the countersunk hole at the upper end of the U-shaped guide sleeve 24. That is, the press installation of the input shaft 23 and the worm gear torsion bar assembly 25 is completed, forming the main shaft worm gear assembly. After the press head 16 moves up to the starting position, the moving base 33 moves to the first position.

[0082] S9. Loosen the locking handle 21 and remove the pressure sleeve 17, U-shaped guide sleeve 24 and spindle worm gear assembly in sequence. At this time, the entire process of pressing the spindle worm gear assembly is completed.

[0083] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. An assembly fixture for the worm gear assembly of the main shaft of an electric steering gear, characterized in that, It includes a moving mechanism for sequentially pressing the worm gear assembly and the worm gear torsion bar assembly, and a right-side positioning and pressing mechanism for pressing the torsion bar and the worm gear assembly, respectively positioned on the left and right positioning holes of the moving base of the moving mechanism, and a left-side positioning and pressing mechanism for pressing the input shaft and the worm gear torsion bar assembly.

2. The assembly fixture for the electric steering gear main shaft worm gear assembly according to claim 1, characterized in that, The moving mechanism includes a transition base plate, a first slider guide rail assembly, a second slider guide rail assembly, and a rodless cylinder disposed on the transition base plate. A moving base is slidably disposed on the first slider guide rail assembly and the second slider guide rail assembly. The rodless cylinder is configured to control the moving base to switch between a first position and a second position. The right positioning and pressing mechanism and the left positioning and pressing mechanism are disposed on the moving base.

3. The assembly fixture for the electric steering gear main shaft worm gear assembly according to claim 2, characterized in that, The rodless cylinder is connected to the movable base via an L-shaped connecting block. The first slider guide rail assembly and the second slider guide rail assembly include multiple sliders. The movable base is connected to the sliders. The right-side positioning and pressing mechanism and the left-side positioning and pressing mechanism are fixed on the movable base.

4. The assembly fixture for the electric steering gear main shaft worm gear assembly according to claim 2, characterized in that, The right-side positioning and pressing mechanism includes a first base, a first positioning sleeve on the first base, a positioning guide sleeve above the first positioning sleeve, a guide pressure sleeve on the positioning guide sleeve, a transition guide pressure sleeve inside the guide pressure sleeve, and a pressure head that cooperates with a servo press above the guide pressure sleeve.

5. The assembly fixture for the electric steering gear spindle worm gear assembly according to claim 4, characterized in that, The first positioning sleeve is a hollow shaft component. Its outer end shaft diameter is clearance-fitted with the countersunk hole of the first base. An annular groove is provided in the middle. The first positioning sleeve is positioned on the first base by bolts. The first positioning sleeve has a through hole in the axial direction for positioning with clearance-fitted with the shaft diameter of the worm gear assembly, and its length is greater than the depth of the countersunk hole of the first base.

6. The electric steering gear spindle worm gear assembly assembly fixture according to claim 5, characterized in that, The positioning guide sleeve is a stepped shaft component. The upper end of the large end shaft diameter is provided with a first countersunk hole for positioning with a clearance fit with the outer diameter of the guide sleeve, and a through hole for accommodating the torsion bar is provided in the middle. The lower end of the small end shaft diameter is provided with a second countersunk hole for positioning with a clearance fit with the upper end shaft diameter of the worm gear assembly.

7. The electric steering gear spindle worm gear assembly assembly fixture according to any one of claims 1 to 6, characterized in that, The left-side positioning and pressing mechanism includes a second base, a second positioning sleeve on the second base, a U-shaped guide sleeve above the second positioning sleeve, a pressing sleeve inside the U-shaped guide sleeve, a guide block and a limiting block on the pressing sleeve, and a locking handle on the pressing sleeve.

8. The assembly fixture for the electric steering gear spindle worm gear assembly according to claim 7, characterized in that, The U-shaped guide sleeve is a hollow component. The upper end is provided with a first countersunk hole that is clearance-fitted with the outer diameter of the pressure sleeve. The first countersunk hole is provided with a U-shaped groove in the radial direction that is clearance-fitted with the width dimension of the guide block. The lower end is provided with a second countersunk hole that is clearance-fitted with the upper diameter of the worm gear torsion bar assembly. Two arc-shaped positioning blocks are provided between the first countersunk hole and the second countersunk hole that are in sync with the groove on the worm gear torsion bar assembly.

9. The assembly fixture for the electric steering gear spindle worm gear assembly according to claim 7, characterized in that, The limiting block is provided with a V-shaped groove for positioning the input shaft, and the inside of the V-shaped groove is provided with an arc surface that avoids the diameter of the input shaft.

10. A method for press-fitting an electric steering gear spindle worm gear assembly, comprising using the electric steering gear spindle worm gear assembly assembly fixture as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Position the worm gear assembly in the first positioning sleeve and place the movable base in the first position; S2. Place the torsion bar positioning device in the inner hole of the worm gear assembly; S3. The pressure tapping sleeve assembly is fitted onto the upper end of the torsion bar, the inner hole of the transition guide sleeve is positioned on the spline at the upper end of the torsion bar, and the countersunk hole at the lower end of the positioning guide sleeve is positioned on the upper shaft diameter of the worm gear assembly. S4. Start the servo press. The servo press pushes the press head down to the upper end face of the guide sleeve. It then moves down through the guide sleeve and the transition guide sleeve to push the torsion bar down into the inner hole of the worm gear assembly. This continues until the end face of the guide sleeve is in contact with the bottom surface of the countersunk hole at the upper end of the positioning guide sleeve. This completes the press-fitting of the torsion bar and the worm gear assembly, forming the worm gear torsion bar assembly. At this point, after the press head moves up to the starting position, the moving base moves to the second position. S5. Remove the worm gear torsion bar assembly from the first positioning sleeve, and then put the worm gear torsion bar assembly into the second positioning sleeve; S6. Place the U-shaped guide sleeve onto the worm gear torsion bar assembly, and position the two arc-shaped positioning blocks on the U-shaped guide sleeve by matching the grooves on the worm gear torsion bar assembly. S7. Take the input shaft and install it into the pressure sleeve. Then take the limit block to position the input shaft. Tighten the locking handle to fix the input shaft in the pressure sleeve. Then remove the limit block and align the guide block with the U-shaped groove on the U-shaped guide sleeve. Place the guide block into the U-shaped guide sleeve. S8. Restart the servo press. The servo press pushes the press head down to the upper end face of the press sleeve. Then, it pushes the upper inner hole of the input shaft down to the upper spline of the torsion bar through the press sleeve until the end face of the press sleeve is in contact with the bottom surface of the countersunk hole at the upper end of the U-shaped guide sleeve. This completes the press-fitting of the input shaft and the worm gear torsion bar assembly, forming the main shaft worm gear assembly. After the press head moves up to the starting position, the moving base moves to the first position. S9. Loosen the locking handle and remove the pressure sleeve, U-shaped guide sleeve and spindle worm gear assembly in sequence. At this point, the entire process of pressing the spindle worm gear assembly is completed.

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