Hydraulic auxiliary gear constant force chemical mechanical polishing device and method

Abstract

The invention discloses a hydraulic auxiliary gear constant-force chemical mechanical polishing device and method, and belongs to the technical field of gear manufacturing and polishing machining device.The hydraulic auxiliary gear constant-force chemical mechanical polishing device comprises a hydraulic system and a slider-crank mechanism, the hydraulic system comprises an oil tank, and the oil tank is communicated with a two-position four-way electromagnetic reversing valve through a pump; a fixed-value pressure reducing valve is communicated between the pump and the two-position four-way electromagnetic directional valve, the two-position four-way electromagnetic directional valve is communicated with an oil cylinder, the oil cylinder is in transmission connection with a rack, a polishing piece is arranged on the rack, the rack is meshed with a polished gear, the rack is in transmission connection with a slider-crank mechanism, and the slider-crank mechanism comprises a slider fixedly connected with the rack. Real-time dynamic, accurate and constant automatic control of the polishing pressure is realized through a hydraulic system and a fixed-value pressure reducing valve, and the polishing uniformity and consistency are improved; the crank sliding block mechanism drives the rack to do reciprocating motion, so that the polished gear continuously rotates forwards and backwards for a circle in the polishing process, efficient and continuous polishing of the whole tooth profile is achieved, and workpieces do not need to be frequently assembled and disassembled or adjusted.

Description

Technical Field

[0001] This invention belongs to the technical field of gear manufacturing and polishing equipment, and particularly relates to a hydraulically assisted constant force chemical mechanical polishing device and method for gears. Background Technology

[0002] As a key component in mechanical transmission systems, the machining accuracy and surface quality of gears have a crucial impact on the performance, reliability, and service life of equipment. With the development of modern manufacturing towards higher precision and performance, the requirements for gear machining are also increasing.

[0003] The most common polishing methods for gears are mechanical polishing, such as belt grinding, grinding wheel grinding, tumbling, and vibratory polishing. However, the pressure control of this type of polishing is not precise, which can easily lead to inconsistent surface accuracy of the gear tooth profile and poor uniformity of polishing quality. Ordinary chemical polishing and electrochemical polishing do not involve mechanical stress and can obtain high-quality polished surfaces. However, due to the lack of mechanical force, it is difficult to control the corrosion rate, which makes it impossible to guarantee the accuracy of the gear tooth profile. Summary of the Invention

[0004] The purpose of this invention is to provide a hydraulically assisted gear constant force chemical mechanical polishing device and method to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides a hydraulically assisted gear constant force chemical mechanical polishing device, comprising a hydraulic system and a crank-slider mechanism. The hydraulic system includes an oil tank, which is connected to a two-position four-way solenoid valve via a pump. A pressure reducing valve is connected between the pump and the two-position four-way solenoid valve. The two-position four-way solenoid valve is connected to a cylinder. The cylinder is driven by a rack, which has a polishing component on it. The rack meshes with the gear being polished. The rack is driven by the crank-slider mechanism. The crank-slider mechanism includes a slider fixedly connected to the rack, and the slider is driven by a drive unit.

[0006] Preferably, the drive unit includes a connecting rod that is drivenly connected to the slider, and a crank is drivenly connected to the end of the connecting rod away from the slider.

[0007] Preferably, a check valve is connected between the pump and the pressure reducing valve.

[0008] Preferably, an overflow valve is connected in parallel between the one-way valve and the fixed-value pressure reducing valve.

[0009] Preferably, a piston is slidably connected inside the cylinder, a push rod is fixedly connected to the piston, the push rod is fixedly connected to the rack, and a through hole is provided between the piston, the push rod, the rack, and the polishing part.

[0010] Preferably, the polishing component is a polishing pad.

[0011] Preferably, the oil tank contains pressurized oil and polishing slurry.

[0012] Preferably, the length of the rack is greater than the circumference of the pitch circle of the polished gear.

[0013] Preferably, the length of the crank is greater than half the circumference of the pitch circle of the polished gear, and the length of the crank is less than half the length of the rack.

[0014] A hydraulically assisted constant-force chemical mechanical polishing method for gears includes the following steps:

[0015] S1. Install the gear to be polished on the frame, ensuring that the gear to be polished can rotate freely around its axis;

[0016] S2. Start the hydraulic system to make the rack mesh with the gear being polished and press against the surface of the gear being polished;

[0017] S3. Start the crank-slider mechanism to make the slider drive the rack to reciprocate, and complete the polishing of the tooth profile surface under constant mechanical pressure and the chemical-mechanical synergy of polishing slurry.

[0018] S4. After polishing, separate the rack from the gear being polished and remove the gear being polished.

[0019] This invention discloses the following technical effects: Real-time dynamic, precise, and constant automatic control of polishing pressure is achieved through a hydraulic system and a fixed-value pressure reducing valve, improving polishing uniformity and consistency; the crank-slider mechanism drives the rack to reciprocate, causing the polished gear to rotate continuously in both directions during the polishing process, achieving efficient and continuous polishing of the entire tooth profile without frequent loading, unloading, or adjustment of the workpiece; the polishing slurry is directly and continuously delivered to the meshing polishing interface of the rack and gear using the hydraulic system's own oil circuit, making the supply method simple and reliable; a two-position four-way solenoid directional valve controls the clamping and disengagement of the rack, facilitating automated loading and unloading. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 This is a schematic diagram of the hydraulically assisted gear constant force chemical mechanical polishing device of the present invention.

[0022] Figure 2 This is a schematic diagram of the connection between the piston and the rack of the present invention.

[0023] In the diagram: 1. Crank; 2. Connecting rod; 3. Slider; 4. Gear to be polished; 5. Polishing pad; 6. Rack; 7. Hydraulic cylinder; 8. Two-position four-way solenoid directional valve; 9. Fixed-value pressure reducing valve; 10. Relief valve; 11. Pump; 12. Oil tank; 13. Check valve; 14. Piston; 15. Push rod. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Reference Figures 1-2 As shown, this embodiment provides a hydraulically assisted gear constant force chemical mechanical polishing device, including a hydraulic system and a crank-slider mechanism. The hydraulic system includes an oil tank 12, which is connected to a two-position four-way solenoid valve 8 via a pump 11. A fixed-value pressure reducing valve 9 is connected between the pump 11 and the two-position four-way solenoid valve 8. The two-position four-way solenoid valve 8 is connected to a cylinder 7, which is driven by a rack 6. A polishing part is provided on the rack 6, which meshes with the polished gear 4. The rack 6 is driven by the crank-slider mechanism, which includes a slider 3 fixedly connected to the rack 6. The slider 3 is driven by a drive unit.

[0027] The hydraulic system and the fixed-value pressure reducing valve 9 achieve real-time dynamic, precise, and constant automatic control of polishing pressure, improving polishing uniformity and consistency. The crank-slider mechanism drives the rack 6 to reciprocate, causing the polished gear 4 to rotate continuously in both directions during the polishing process, achieving efficient and continuous polishing of the entire tooth profile without frequent loading, unloading, or adjustment of the workpiece. The hydraulic system itself delivers pressure oil through its oil circuit, directly and continuously supplying polishing slurry to the meshing polishing interface between the rack 6 and the polished gear 4, making the supply method simple and reliable. The two-position four-way solenoid directional valve 8 controls the clamping and disengagement of the rack 6, facilitating automated loading and unloading.

[0028] The scheme is further optimized. The drive unit includes a connecting rod 2 that is connected to the slider 3 in a transmission manner. The end of the connecting rod 2 away from the slider 3 is connected to a crank 1 in a transmission manner.

[0029] The slider 3 is rigidly connected to the end face of the rack 6 in the cylinder 7; the crank 1 is the driving component, and its rotation center is parallel to the rotation center of the polished gear 4.

[0030] The scheme has been further optimized by connecting a one-way valve 13 between pump 11 and the fixed-value pressure reducing valve 9.

[0031] To further optimize the design, an overflow valve 10 is connected in parallel between the one-way valve 13 and the fixed-value pressure reducing valve 9.

[0032] Pump 11 is a fixed displacement pump that provides power; overflow valve 10 acts as a pressure regulator; check valve 13 prevents backflow of the medium; pressure reducing valve 9 ensures that the oil pressure entering the rodless chamber (left) of cylinder 7 remains constant; two-position four-way solenoid directional valve 8 is used to control the extension and retraction of push rod 15 in cylinder 7. When the directional valve is in the left position, push rod 15 extends and pushes rack 6 to press against the tooth profile of polished gear 4. When the two-position four-way solenoid directional valve 8 is in the right position, push rod 15 retracts, causing rack 6 to separate from polished gear 4.

[0033] In a further optimized design, a piston 14 is slidably connected inside the cylinder 7, and a push rod 15 is fixedly connected to the piston 14. The push rod 15 is fixedly connected to the rack 6, and through holes are provided between the piston 14, push rod 15, rack 6, and polishing parts to facilitate the flow of polishing slurry into the polishing pad 5 and the meshing surface of the tooth profile. The polishing pad 5 is adhered to the surface of the rack 6.

[0034] The solution was further optimized, and the polishing component was polishing pad 5.

[0035] The design was further optimized by adding pressurized oil and polishing slurry to tank 12. The polishing slurry consists of a weak acid, oxidant, abrasive particles, and other additives.

[0036] The design was further optimized so that the length of rack 6 is greater than the circumference of the pitch circle of the polished gear 4.

[0037] Further optimization involves making the length of crank 1 greater than half the circumference of the pitch circle of the gear 4 being polished, and the length of crank 1 less than half the length of rack 6. This ensures that one rotation of crank 1 guarantees one rotation in both directions of the gear without separating from rack 6, thus achieving reciprocating polishing of the gear tooth profile surface.

[0038] The constant pressure reducing valve 9 in the hydraulic system ensures constant oil inlet pressure, meaning the rack 6 constantly presses against the polished tooth profile, maintaining constant polishing pressure. The hydraulic transmission medium is a mixture of pressurized oil and polishing slurry, solving the problem of uniform application of the polishing slurry and eliminating the need for a dedicated slurry dripping device. This medium simultaneously serves as both a transmission and polishing agent. Through the design of the crank 1 component dimensions, it is ensured that the gear rotates one revolution in both directions without separating from the rack 6, achieving continuous and uniform polishing of the tooth profile surface. This method differs from traditional mechanical polishing in that it introduces a polishing pad 5, chemical liquid, and abrasive particles, making it a chemical mechanical polishing method. This results in a higher precision polished surface. Furthermore, by using a hydraulic system to control the polishing pressure, it ensures constant pressure under any polishing state (i.e., real-time dynamic and precise control of polishing pressure), features not found in pure mechanical polishing. It also differs from ordinary chemical polishing in that, in addition to utilizing chemical corrosion, this method combines the precise meshing of the rack 6 and gear. It not only provides mechanical pressure but also ensures that the pressure is applied evenly to the tooth profile surface through the meshing of the rack 6 and gear, thus precisely controlling the polishing tooth profile accuracy.

[0039] A hydraulically assisted constant-force chemical mechanical polishing method for gears includes the following steps:

[0040] S1. Install the polished gear 4 on the working spindle of the machine frame, ensuring that the polished gear 4 can rotate freely around its axis. Initially, the two-position four-way solenoid valve 8 should be in the right position, so that the rack 6 is in the retracted (right end) position and has no contact with the polished gear 4.

[0041] S2. Start the hydraulic system to make rack 6 mesh with the polished gear 4 and press against the surface of the polished gear 4; the oil in oil tank 12 flows sequentially through check valve 13, pressure reducing valve 9, left position of two-position four-way solenoid directional valve 8, and rodless chamber of cylinder 7, causing push rod 15 to extend. The polishing pad 5, which is in contact with rack 6, will press against the tooth profile surface of polished gear 4 under the pushing action of push rod 15; this thrust is adjusted by pressure reducing valve 9, which has the function of automatically and dynamically adjusting the outlet pressure to a certain value in real time, that is, ensuring that the polishing pressure is constant; in addition, the through holes inside piston 14 of cylinder 7, push rod 15, rack 6 and polishing pad 5 continuously deliver oil to the contact area between polishing pad 5 and the tooth profile of polished gear 4, filling the meshing surface;

[0042] S3. Start the crank-slider mechanism, driving crank 1 to rotate at a constant speed. This drives slider 3 and the rigidly connected rack 6 to perform reciprocating linear motion via connecting rod 2. Because slider 3 is rigidly connected to the end face of rack 6, rack 6 also performs synchronous reciprocating linear motion. The reciprocating motion of rack 6 forces the polished gear 4, which meshes with it, to rotate in the corresponding forward and reverse directions. Within one complete reciprocating stroke of rack 6 (corresponding to one rotation of crank 1), the gear completes one forward rotation and then one reverse rotation. During this process, the entire tooth profile surface of the polished gear 4 contacts the polishing pad 5 on the reciprocating rack 6 in sequence. Under the synergistic effect of constant mechanical pressure and the chemical-mechanical properties of the polishing slurry, efficient and uniform polishing is achieved.

[0043] S4. After polishing, control the two-position four-way solenoid directional valve 8 to operate in the right position. Pressurized oil enters the rod chamber of cylinder 7 through the right position (P->B) of the directional valve, while the oil in the rodless chamber flows back to the oil tank 12 through the right position (A->T) of the two-position four-way solenoid directional valve 8. Push rod 15 drives rack 6 to move to the left, separating it from the gear. Turn off hydraulic pump 11. At this time, the polished gear 4 can be removed from the machine tool.

[0044] Oil tank 12 stores the oil medium containing polishing slurry. A metering pump 11 draws oil from oil tank 12 and outputs pressurized oil. An overflow valve 10 is connected in parallel between the outlet of pump 11 and oil tank 12 to limit the maximum system pressure, acting as a safety valve and pressure stabilizer. A check valve 13 is installed downstream of the pump 11 outlet to prevent backflow of oil. The outlet of the pressure reducing valve is connected to the lower inlet (denoted by P, hereinafter the same) of the two-position four-way solenoid directional valve 8, and the lower outlet (denoted by T, hereinafter the same) of the two-position four-way solenoid directional valve 8 is connected to oil tank 12. When the two-position four-way solenoid directional valve 8 is in the left position (as shown in the diagram), its upper outlet (denoted by A, hereinafter the same) is connected to port P, and its upper inlet (denoted by B, hereinafter the same) is connected to port T. Port A connects to the rodless chamber (left chamber) of cylinder 7, and the rod chamber (right chamber) of cylinder 7 connects to port B of the two-position four-way solenoid directional valve 8. A rack 6 is fixedly mounted on the front end of the piston 14 and push rod 15 of cylinder 7. A polishing pad 5 is firmly adhered to the working tooth surface (the surface that meshes with the gear) of rack 6. The key design feature is that interconnected through holes are provided inside the piston 14, push rod 15, rack 6, and polishing pad 5 of cylinder 7, forming a flow channel from the rodless chamber of cylinder 7 to the working surface of polishing pad 5. Under pressure, the oil medium (including polishing slurry) is continuously supplied to the contact area between polishing pad 5 and gear tooth profile through this channel. A constant pressure reducing valve 9 ensures that the pressure entering the rodless chamber of cylinder 7 is constant, thereby guaranteeing a constant contact pressure between polishing pad 5 and gear tooth profile surface. When the reversing valve is in the right position, port P is connected to port B, and port A is connected to port T. Pressurized oil enters the rod chamber of cylinder 7, pushing piston 14 and rack 6 to move to the right, causing them to separate from the polished gear 4.

[0045] One end of the crank 1 is installed on the output shaft of a driving motor (not shown in the figure) and can rotate uniformly around a fixed axis. One end of the connecting rod 2 is connected to the other end of the crank 1 through a revolute pair (hinge). The other end of the connecting rod 2 is connected to the slider 3 through a revolute pair (hinge). The slider 3 is constrained on the straight guide rail of the frame (not shown in the figure) and can only move linearly in the horizontal direction (the same as the movement direction of the rack 6). The end face of the slider 3 and the end face of the rack 6 in the oil cylinder 7 are rigidly connected by bolts or other means. Therefore, the rotational motion of the crank 1 is converted into the reciprocating linear motion of the slider 3 through the connecting rod 2, and then the rack 6 rigidly connected to it is driven to perform synchronous reciprocating linear motion.

[0046] Length L of the rack 6: It must be greater than the circumference C of the pitch circle of the polished gear 4 (i.e., L > C). This is the basic condition to ensure that within the entire reciprocating motion stroke of the rack 6, the polished gear 4 can continuously rotate (one full revolution forward + one full revolution backward) without disengaging from the rack 6.

[0047] Length R of the crank : It must be greater than half of the circumference of the gear pitch circle (R > C / 2) and less than half of the length of the rack 6 (R < L / 2). Meeting R > C / 2 ensures that when the crank 1 rotates one full circle, the stroke of the rack 6 driven by it is sufficient to drive the gear to rotate one full circle forward and one full circle backward. Meeting R < L / 2 is to ensure that the rack 6 has enough remaining length to accommodate the gear and avoid the gear disengaging from the end of the rack 6 at the stroke limit position. These two conditions together ensure that within a complete rotation cycle of the crank 1, the gear can smoothly complete the polishing process of rotating one full circle forward followed by one full circle backward.

[0048] The polishing slurry is a functional component mixed in a hydraulic oil medium, mainly including: weak acids (such as citric acid, oxalic acid, etc.) to provide a mild corrosion environment, soften the metal surface oxide or promote chemical reactions; oxidants (such as hydrogen peroxide, ferric nitrate, etc.) to promote the formation of a softened layer or oxide layer on the surface of the gear material (usually steel) that is easy to remove; abrasives (such as silica, silicon carbide micropowder, etc.) to provide mechanical grinding action and remove the material layer softened by chemical action; other additives: such as dispersants (to keep the abrasives suspended), surfactants (to improve wettability), corrosion inhibitors (to protect non-polished areas), pH regulators, etc. The formula of the slurry needs to be optimized according to the gear material, the required surface roughness, and the removal rate.

[0049] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0050] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A hydraulically assisted gear constant force chemical mechanical polishing device, characterized in that: The device includes a hydraulic system and a crank-slider mechanism. The hydraulic system includes an oil tank (12), which is connected to a two-position four-way solenoid valve (8) via a pump (11). A pressure reducing valve (9) is connected between the pump (11) and the two-position four-way solenoid valve (8). The two-position four-way solenoid valve (8) is connected to a cylinder (7). The cylinder (7) is driven by a rack (6). The rack (6) is provided with a polishing part. The rack (6) meshes with a polished gear (4). The rack (6) is driven by the crank-slider mechanism. The crank-slider mechanism includes a slider (3) fixedly connected to the rack (6). The slider (3) is driven by a drive unit.

2. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: The drive unit includes a connecting rod (2) that is driven to the slider (3), and a crank (1) is driven to the end of the connecting rod (2) away from the slider (3).

3. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: A check valve (13) is connected between the pump (11) and the fixed-value pressure reducing valve (9).

4. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 3, characterized in that: An overflow valve (10) is connected in parallel between the one-way valve (13) and the fixed-value pressure reducing valve (9).

5. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: A piston (14) is slidably connected inside the oil cylinder (7). A push rod (15) is fixedly connected to the piston (14). The push rod (15) is fixedly connected to the rack (6). A through hole is provided between the piston (14), the push rod (15), the rack (6), and the polished part.

6. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: The polishing component is a polishing pad (5).

7. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: The oil tank (12) contains pressurized oil and polishing slurry.

8. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 1, characterized in that: The length of the rack (6) is greater than the circumference of the pitch circle of the polished gear (4).

9. The hydraulically assisted gear constant force chemical mechanical polishing device according to claim 2, characterized in that: The length of the crank (1) is greater than half the circumference of the pitch circle of the polished gear (4), and the length of the crank (1) is less than half the length of the rack (6).

10. A hydraulically assisted constant-force chemical mechanical polishing method for gears, employing the hydraulically assisted constant-force chemical mechanical polishing apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Install the polished gear (4) on the frame, ensuring that the polished gear (4) can rotate freely around its axis; S2. Start the hydraulic system to make the rack (6) mesh with the polished gear (4) and press against the surface of the polished gear (4); S3. Start the crank-slider mechanism so that the slider (3) drives the rack (6) to reciprocate and complete the polishing of the tooth profile surface under constant mechanical pressure and the chemical-mechanical synergy of the polishing slurry. S4. After polishing, separate the rack (6) from the polished gear (4) and remove the polished gear (4).

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