An apparatus and method for polishing narrow ring groove sidewalls

Abstract

The application discloses a device and method for polishing narrow ring groove sidewalls, which comprises a clamping mechanism, a trimming mechanism, a vertical plate, a polishing mechanism, a vertical module, a crossbeam, a horizontal module, a control cabinet and a base. The application adopts a double-station normal feed processing mode and trimming mode, so that the polishing tool is stressed at both ends, the skewing problem of the polishing tool caused by unilateral stress is solved, the flatness of the ring groove sidewall and the trimming surface of the polishing tool is improved, and the polishing of the ring groove sidewall with a rectangular section is realized. The application uses force feedback to control the feed of the polishing tool, and utilizes a disc spring to further improve the stability of the polishing force, so that the deviation of the polishing force is reduced. The simultaneous action of the two effects is beneficial to improving the accuracy and stability of the polishing force size in force feedback control, avoiding overloading polishing, and finally obtaining a correct geometric shape and a low roughness surface. The application has the advantages of high processing efficiency, good surface quality and high flatness precision.

Description

Technical Field

[0001] This invention relates to annular groove polishing technology, and particularly to an apparatus and method for polishing the sidewalls of narrow annular grooves. Background Technology

[0002] Rotary seals are critical components in vehicle transmission systems, preventing hydraulic oil leakage from the gap between rotating and stationary parts and maintaining stable oil pressure. An expansion ring seal is a circumferentially open sealing ring whose sealing partner is typically a rotating shaft with an annular groove. The groove is small and narrow, with its width and depth on the order of millimeters. The expansion ring seal is assembled in the annular groove of the shaft and, during operation, is pressed tightly against the inner cylindrical surface of the bushing and the sidewall of the annular groove under hydraulic pressure, forming two pairs of sealing surfaces. Improving the contact state between the expansion ring seal and the sidewall of the annular groove, and reducing the coefficient of friction between the friction pairs, is one of the important means to prevent premature failure of rotating dynamic seals in hydraulic circuits of mechanical transmission devices.

[0003] The mounting groove of the expansion ring is machined by hard turning. The sidewalls of the groove have defects such as burrs and cracks, with a roughness greater than Ra 1.6 μm. Polishing the sidewalls of the groove can remove surface defects and reduce sidewall roughness, thereby reducing friction and wear on the expansion ring, extending its service life, and decreasing the frequency of replacement.

[0004] For rectangular cross-section annular grooves with width and depth in the millimeter range, achieving high surface quality, high flatness, and high processing efficiency in polishing the sidewalls requires the design of specialized polishing devices and methods. Patent CN213917553 U discloses a "grinding device for the inner ring groove of a pull-type release bearing." This invention uses a grinding wheel to grind the inner ring of a pull-type release bearing mounted on the workpiece spindle. The grinding wheel uses displacement control for radial feed to grind a narrow groove on the bearing inner ring. However, the grinding wheel does not feed normally to the sidewall of the narrow groove, resulting in poor surface quality and making it impossible to polish the pre-machined sidewall of the narrow groove. Patent CN 108515419B discloses a "grinding device for the inner ring groove of a ball bearing." This invention uses a moving rod to control the feed of the grinding ball, which contacts the groove to polish the inner ring groove of the bearing. However, limited by the shape of the grinding wheel and the feed direction, this invention cannot be used to polish the sidewall of annular grooves with rectangular cross-sections. Patent CN 110076678 A discloses "an automatic polishing device for bushing grooves". This invention uses a small-sized polishing wheel to polish the grooves, and the displacement and feed of the polishing wheel are controlled by a lead screw. The polishing wheel clamping rod is subjected to force on one side, which is prone to skew and cannot guarantee the flatness of the polished surface. In addition, the grinding speed and grinding pressure allowed by the polishing wheel are limited, which is not conducive to improving processing efficiency.

[0005] In summary, existing annular groove polishing devices cannot polish the sidewalls of pre-processed millimeter-scale rectangular cross-section annular grooves while ensuring sidewall flatness and surface quality. Summary of the Invention

[0006] To overcome the problems existing in the prior art, the purpose of this invention is to design an apparatus and method for polishing the sidewalls of narrow annular grooves that can both ensure the flatness and surface quality of the machined surface and polish the sidewalls of annular grooves with a rectangular cross-section on the order of millimeters.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An apparatus for polishing the sidewalls of a narrow annular groove includes a clamping mechanism, a trimming mechanism, a vertical plate, a polishing mechanism, a vertical module, a crossbeam, a horizontal module, a control cabinet, and a base.

[0009] The base includes four columns and a support plate. The support plate is fixed to the top of the four columns, and the columns are fixed to the support plate in the front-to-back direction.

[0010] The horizontal module is fixed on the machine tool base in the left-right direction, the crossbeam is installed on the horizontal module in the front-back direction and moves left and right along the horizontal module, and the vertical module is installed on the crossbeam in the vertical direction.

[0011] The polishing mechanism includes a polishing tool, a servo motor, a square bracket, a disc spring, and a force sensor. The polishing tool is fixedly connected to the servo motor, which is fixed to the inner side of the left end of the square bracket. The right end of the square bracket is mounted on the vertical module via the force sensor and the disc spring. A rectangular hole is provided along the height direction on the upright plate, and the square bracket passes through the rectangular hole on the upright plate.

[0012] The clamping mechanism has two sets, which are symmetrically fixed on the upright plate on both sides of the polishing tool. The clamping mechanism consists of a three-jaw chuck, a reducer and a DC motor. The three-jaw chuck is connected to the DC motor through the reducer. Each of the two three-jaw chucks clamps one workpiece. The distance between the centers of the two three-jaw chucks is the sum of the diameter of the annular groove shaft surface and the outer diameter of the polishing tool.

[0013] The trimming mechanism includes a trimming oilstone, an oilstone clamp, and a trimming module. The trimming oilstone is pressed onto the trimming module by the oilstone clamp. The trimming module is mounted on a vertical plate and located above the clamping mechanism.

[0014] Furthermore, the polishing tool is a circular tool, including a grinding wheel or a polishing wheel.

[0015] Furthermore, during processing, each of the two three-jaw chucks clamps one workpiece, and the polishing tool contacts both workpieces simultaneously, with the line connecting the contact points passing exactly through the axis of the polishing tool.

[0016] Furthermore, there are two trimming mechanisms, which are symmetrically placed on both sides of the polishing tool. When the polishing tool is trimmed in situ, the polishing tool is in contact with both oilstones at the same time, and the line connecting the contact points passes through the axis of the polishing tool.

[0017] Furthermore, the dressing stone is installed on the dressing module, and when dressing the polishing tool, the dressing stone reciprocates radially along the polishing tool.

[0018] Furthermore, the crossbeam is simultaneously mounted on two horizontal modules.

[0019] A method for polishing the sidewalls of narrow annular grooves, utilizing a device for polishing the sidewalls of narrow annular grooves to achieve constant pressure control, includes the following steps:

[0020] A. Measure the distance between the sidewall of the annular groove to be processed and the bottom surface of the workpiece. Select two workpieces with similar distances for clamping. If necessary, use shims to adjust so that the sidewalls of the annular grooves to be processed on the two workpieces are on the same vertical plane.

[0021] B. Install the polishing tool, return the horizontal and vertical modules to zero first, and then manually control the feed of the vertical and horizontal modules so that the polishing tool is just inserted into the annular groove without contacting the workpiece.

[0022] C. Adjust the height of the polishing tool by adjusting the position of the vertical module slider to ensure that the axis of the polishing tool and the axis of the two workpieces are on the same straight line;

[0023] D. Start the DC motor and servo motor to supply polishing fluid to the polishing area, and the workpiece and polishing tool rotate simultaneously.

[0024] E. The horizontal module drives the polishing tool to feed 1-50μm along the normal of the processing surface, applying polishing pressure to the processing surface. The force sensor detects the pressure in real time and provides force feedback control for the feed of the polishing tool. When the detected pressure is lower than the set value, the horizontal module feeds towards the workpiece to increase the processing surface pressure. When the detected pressure is greater than the set value, the horizontal module retreats to reduce the processing surface pressure.

[0025] F. After polishing is completed, the polishing tool is removed from the processed surface, ending this processing step;

[0026] G. Polish only one annular groove sidewall at a time. After polishing, if the polishing tool surface is flat, rotate the workpiece 180° so that the other sidewall of the annular groove faces the polishing tool. Then repeat step AF to process the other annular groove sidewall. If the polishing tool surface is skewed, control the polishing tool to move near the dressing stone, start the dressing module, and the dressing stone reciprocates. Then proceed to step E, where the polishing tool is dressed under constant pressure. After dressing, prepare to polish the next annular groove sidewall.

[0027] Compared with existing technologies, it has at least the following beneficial effects:

[0028] 1. This invention adopts a dual-station normal feed processing method and dressing method, so that the polishing tool is subjected to force at both ends, which solves the problem of skewness caused by the polishing tool being subjected to force on one side. This is beneficial to improving the flatness of the annular groove sidewall and the dressing surface of the polishing tool, and realizes the polishing of the annular groove sidewall with a rectangular cross section.

[0029] 2. This invention uses force feedback to control the feed of the polishing tool and utilizes a disc spring to further improve the stability of the polishing force. Since the disc spring will deform slightly under axial force, it has the following two characteristics: First, when the polishing tool and the processing surface wear, the disc spring will automatically extend to compensate for the wear, so that the processing surface always keeps in contact and prevents the polishing force from dropping significantly due to lack of contact. Second, when the actual feed of the module is too large or too small, causing the polishing force to deviate from the set value, the disc spring can also partially offset the feed deviation by deformation, thereby reducing the deviation of the polishing force. The two effects working together help to improve the accuracy and stability of the polishing force during force feedback control, avoid overload polishing, and ultimately obtain the correct geometry and low roughness surface.

[0030] 3. The dressing module fixed on the vertical plate in this invention drives the dressing oilstone to reciprocate, which reduces the adverse effect of uneven wear of the dressing oilstone on the dressing effect of the polishing tool, improves the flatness of the dressing surface of the polishing tool, and thus improves the flatness of the sidewall of the ring groove. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural schematic diagram of the device of the present invention.

[0032] Figure 2 This is a schematic diagram of the workpiece structure.

[0033] Figure 3 This is a schematic diagram of the clamping mechanism.

[0034] Figure 4 This is a schematic diagram of the polishing mechanism.

[0035] Figure 5 For the modification of the structural diagram

[0036] In the diagram: 1. Workpiece, 2. Clamping mechanism, 3. Polishing mechanism, 4. Dressing mechanism, 5. Vertical module, 6. Crossbeam, 7. Horizontal module, 8. Control cabinet, 9. Base, 10. Vertical plate, 21. Three-jaw chuck, 22. Reducer, 23. DC motor, 31. Polishing tool, 32. Servo motor, 33. Square bracket, 34. Force sensor, 35. Disc spring, 41. Oilstone clamp, 42. Dressing oilstone, 43. Dressing module. Detailed Implementation

[0037] To further illustrate the rotor balancing device and method described in this invention, the invention will be further described below with reference to the accompanying drawings. However, this should not be construed as defining the scope of the invention. In this invention, it is understood that the terms "center," "upper," "lower," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0038] An apparatus for polishing the sidewalls of a narrow annular groove includes a clamping mechanism 2, a polishing mechanism 3, a trimming mechanism 4, a vertical plate 10, a vertical module 5, a crossbeam 6, a horizontal module 7, a control cabinet 8, and a base 9.

[0039] The clamping mechanism 2 is fixed on the vertical plate 10 and consists of two sets of three-jaw chucks 21, a reducer 22 and a DC motor 23. The two three-jaw chucks 21 are symmetrically placed on both sides of the polishing tool 31, each clamping a workpiece 1. The center distance between them is the sum of the diameter of the annular groove shaft surface and the outer diameter of the polishing tool 31.

[0040] The polishing mechanism 3 is mounted on the vertical module 5 and includes a polishing tool 31, a servo motor 32, a square bracket 33, a force sensor 34, and a disc spring 35.

[0041] The trimming mechanism 4 is mounted on the vertical plate 10, located above the clamping mechanism 2, and consists of an oilstone clamp 41, a trimming oilstone 42, and a trimming module 43. The maximum distance between the oilstones is slightly larger than the outer diameter of the polishing tool 31.

[0042] The vertical module 5 is mounted on the machine tool base 9 via the crossbeam 6 and the horizontal module 7. The range of motion of the vertical module 5 is sufficient to cover the processing position and in-situ finishing position of the polishing tool 31.

[0043] Furthermore, there are two of each of the three-jaw chuck 21, reducer 22 and DC motor 23, which are symmetrically placed on both sides of the polishing tool 31. During processing, each of the two three-jaw chucks 21 clamps one workpiece 1, and the polishing tool 31 contacts both workpieces 1 at the same time. The line connecting the contact points passes through the axis of the polishing tool 31. The polishing tool 31 is subjected to symmetrical force on both sides, which prevents the polishing tool 31 from tilting due to force on one side, thereby improving the flatness and surface quality of the final processed surface.

[0044] Furthermore, the force sensor 34 detects the pressure of the polishing tool 31 on the workpiece 1 in real time and feeds the pressure signal back to the control system to realize the force feedback control of the axial feed of the polishing tool 31.

[0045] Furthermore, the disc spring 35 deforms when the device applies pressure to the workpiece 1, allowing the polishing tool 31 to retract along the axial direction, thus playing an energy storage role. On the one hand, when the polishing tool 31 and the processing surface wear down, the disc spring 35 will automatically extend to compensate for the wear, ensuring that the processing surface always remains in contact, and preventing the loss of contact between the processing surface and the polishing tool 31 from causing a large change in polishing pressure. On the other hand, when the actual feed amount of the horizontal module 7 is too large or too small, causing a deviation between the polishing force and the set value, the disc spring 35 can also partially offset the feed amount deviation by relying on deformation, thereby reducing the deviation of the polishing force.

[0046] Furthermore, there are two of each of the trimming oilstone 42, oilstone clamp 41, and trimming module 43, which are placed symmetrically on both sides of the polishing tool 31. When the polishing tool 31 is trimmed in situ, the polishing tool 31 contacts the two oilstones at the same time, and the line connecting the contact points passes through the axis of the polishing tool 31. The polishing tool 31 is subjected to symmetrical force on both sides, which prevents the polishing tool 31 from tilting due to force on one side and improves the flatness of the trimmed surface of the polishing tool 31.

[0047] Furthermore, when the dressing stone 42 is mounted on the dressing module 43 and dressing the polishing tool 31, the dressing stone 42 can reciprocate radially along the polishing tool 31, reducing the tilting problem of the dressing surface caused by uneven wear of the dressing stone 42 and improving the flatness of the dressed surface of the polishing tool 31.

[0048] Furthermore, there are two horizontal modules 7, and the crossbeam 6 is installed on both horizontal modules 7 simultaneously to improve the system rigidity.

[0049] Furthermore, the crossbeam is simultaneously mounted on two horizontal modules.

[0050] A method for polishing the sidewalls of narrow annular grooves, utilizing a device for polishing the sidewalls of narrow annular grooves to achieve constant pressure control, includes the following steps:

[0051] A. Measure the distance between the side wall 12 of the ring groove to be processed and the bottom surface 13 of the workpiece. Select two workpieces 1 that are close to each other for clamping. The workpiece 1 is clamped and positioned on the three-jaw chuck 21 by relying on the inner hole 11 and the bottom surface 13 of the workpiece. This ensures that the side wall 12 of the ring groove to be processed after the two workpieces 1 are clamped is in the same plane. If necessary, shims need to be added between the bottom surface 13 of the workpiece and the three-jaw chuck 21 to adjust them to the same plane.

[0052] B. Install polishing tool 31, return all modules to zero, and control the feed of vertical module 5 and horizontal module 7 with the controller so that polishing tool 31 is just inserted into the annular groove but does not contact workpiece 1.

[0053] C. Finely adjust the height of the polishing tool 31 to ensure that the axis of the polishing tool 31 and the axis of the two workpieces 1 are on the same straight line;

[0054] D. Start the DC motor 23 and servo motor 32. The workpiece 1 and polishing tool 31 can rotate in the same direction or in opposite directions according to the actual processing requirements.

[0055] E. The controller controls the horizontal module 7 to drive the polishing tool 31 to make a 1-50μm micro-feed along the normal of the processing surface, applying polishing pressure to the processing surface. The force sensor 34 detects the pressure in real time and provides force feedback control for the feed of the polishing tool 31. When the detected pressure is lower than the set value, the horizontal module 7 feeds towards the workpiece 1 to increase the pressure on the processing surface. When the detected pressure is greater than the set value, the horizontal module 7 retracts to reduce the pressure on the processing surface, and finally maintains the pressure on the processing surface basically constant.

[0056] F. After polishing is completed, the polishing tool 31 leaves the processing surface, the module returns to zero, and the current processing ends;

[0057] G. After each processing is completed, if the surface of the polishing tool 31 is flat, the next batch of workpieces 1 can be processed after changing workpiece 1. If the surface of the polishing tool 31 is crooked, the polishing tool 31 is moved to the vicinity of the dressing stone 42, the dressing module 43 is started, the dressing stone 42 reciprocates, and then the steps similar to E are repeated. The polishing tool 31 and the dressing stone 42 are dressed under constant pressure. After the dressing is completed, the next batch of workpieces 1 can be processed.

[0058] The above description presents two embodiments that satisfy the claims of this application, tailored to specific circumstances, and should not be construed as limiting the specific embodiments of this application to these two methods. Those skilled in the art, guided by the teachings of this application, may make various other modifications without departing from the spirit and scope of the claims, all of which shall fall within the protection scope of this application.

Claims

1. An apparatus for polishing the sidewalls of a narrow annular groove, characterized by: The polishing machine comprises a clamping mechanism (2), a trimming mechanism (4), a vertical plate (10), a polishing mechanism (3), a vertical module (5), a crossbeam (6), a horizontal module (7), a control cabinet (8) and a base (9). The base (9) comprises four vertical columns and a support plate fixed on the top of the four vertical columns, and the vertical plate (10) is fixed on the support plate in the front-rear direction. The horizontal module (7) is fixed on the machine tool base (9) in the left-right direction, the crossbeam (6) is installed on the horizontal module (7) in the front-rear direction and moves left and right along the horizontal module (7), and the vertical module (5) is installed on the crossbeam (6) in the vertical direction. The polishing mechanism (3) comprises a polishing tool (31), a servo motor (32), a square bracket (33), a disc spring (35) and a force sensor (34), the polishing tool (31) is fixedly connected with the servo motor (32), the servo motor (32) is fixed on the inner side of the left end of the square bracket (33), the right end of the square bracket (33) is installed on the vertical module (5) through the force sensor (34) and the disc spring (35), and a rectangular hole is arranged on the vertical plate (10) in the height direction, and the square bracket (33) penetrates through the rectangular hole on the vertical plate (10). The clamping mechanism (2) is symmetrical and fixed on the vertical plate (10) on both sides of the polishing tool (31), the clamping mechanism (2) comprises a three-jaw chuck (21), a speed reducer (22) and a DC motor (23), the three-jaw chuck (21) is connected with the DC motor (23) through the speed reducer (22), two three-jaw chucks (21) clamp one workpiece (1) respectively, and the distance between the centers of the two three-jaw chucks (21) is the sum of the diameter of the annular groove axial surface and the outer diameter of the polishing tool (31). The trimming mechanism (4) comprises a trimming oilstone (42), an oilstone clamp (41) and a trimming module (43), the trimming oilstone (42) is pressed on the trimming module (43) by the oilstone clamp (41), and the trimming module (43) is installed on the vertical plate (10) and located above the clamping mechanism (2).

2. The apparatus of claim 1 wherein: The polishing tool (31) is a circular tool, comprising a grinding wheel or a polishing wheel.

3. The apparatus of claim 1 wherein: During processing, two three-jaw chucks (21) clamp one workpiece (1) respectively, the polishing tool (31) contacts two workpieces (1) at the same time, and the connecting line of the contact points passes through the axis of the polishing tool (31).

4. The apparatus of claim 1 wherein: The trimming mechanism (4) is symmetrical and placed on both sides of the polishing tool (31), and the polishing tool (31) contacts two trimming oilstones (42) at the same time when trimming the polishing tool (31) in situ, and the connecting line of the contact points passes through the axis of the polishing tool (31).

5. The apparatus of claim 1 wherein: The trimming oilstone (42) is installed on the trimming module (43), and the trimming oilstone (42) reciprocates along the radial direction of the polishing tool (31) when trimming the polishing tool (31).

6. The apparatus of claim 1 wherein: The crossbeam (6) is installed on two horizontal modules (7) at the same time.

7. A method for polishing the sidewalls of a narrow annular groove, using the device for polishing the sidewalls of a narrow annular groove according to claim 1 to achieve constant pressure control, characterized in that: The method comprises the following steps: A, measure the distance between the side wall of the ring groove to be processed and the bottom surface of the workpiece (1), select two workpieces (1) with similar distances for clamping, and use shims to adjust if necessary, so that the side walls of the ring grooves to be processed of the two workpieces (1) are in the same vertical plane; B, install the polishing tool (31), make the horizontal module (7) and the vertical module (5) return to zero first, then manually control the feed of the vertical module (5) and the horizontal module (7), so that the polishing tool (31) just fits into the ring groove and does not contact the workpiece (1); C, adjust the height of the polishing tool (31) by adjusting the position of the vertical module (5) slider, to ensure that the axis of the polishing tool (31) and the axes of the two workpieces (1) are in the same straight line; D, start the DC motor (23) and the servo motor (32) to supply polishing liquid to the polishing area, and the workpiece (1) rotates at the same time as the polishing tool (31); E, the horizontal module (7) drives the polishing tool (31) to feed along the normal of the processing surface by 1-50μm, to apply polishing pressure to the processing surface, and the force sensor (34) detects the pressure in real time and controls the feed of the polishing tool (31) with force feedback, when the detected pressure is lower than the set value, the horizontal module (7) feeds towards the workpiece (1) to increase the processing surface pressure, when the detected pressure is greater than the set value, the horizontal module (7) retreats to reduce the processing surface pressure; F, after polishing, the polishing tool (31) leaves the processing surface, and the processing is ended; G, only one ring groove side wall is polished each time, after polishing, if the surface of the polishing tool (31) is flat, the workpiece (1) is turned over by 180° to make the other side wall of the ring groove face the polishing tool (31), then the steps A-F are repeated to process the other side ring groove side wall, if the surface of the polishing tool (31) is skewed, the polishing tool (31) is moved to the vicinity of the dressing stone (42), the dressing module (43) is started, the dressing stone (42) reciprocates, then step E is turned to, the polishing tool (31) is dressed with constant pressure, after dressing, the next ring groove side wall is prepared for polishing.

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