A high-precision gear grinding machine hydraulic automatic clamping drive device

Abstract

This utility model relates to the field of machining technology, specifically a high-precision gear grinding machine hydraulic automatic clamping drive device, including a drive base, a stepped cylindrical mandrel, a cylinder, an annular piston, and a hydraulic expansion sleeve. The drive base is fixedly connected to the indexing plate of the gear grinding machine. A lower center is provided at the top of the mandrel, and the cylinder is fitted around the mandrel to form a stepped cavity. The annular piston moves axially under the drive of hydraulic oil, compressing the hydraulic expansion sleeve to expand radially and clamp the gear blank workpiece. Automatic control is achieved through oil inlet and return channels. The device combines center positioning and hydraulic expansion to improve centering accuracy and clamping uniformity, avoid grinding wheel interference, adapt to high-speed grinding, and can be interfaced with automation systems, making it suitable for high-precision gear machining.

Description

Technical Field

[0001] This utility model relates to the field of machining technology, specifically a high-precision gear grinding machine hydraulic automatic clamping drive device. Background Technology

[0002] With the rapid development of machining technology, high-precision gears, as core components for transmitting motion and power, directly determine the transmission efficiency, operational stability, and service life of equipment. Especially in high-end manufacturing fields such as new energy vehicles, aerospace, precision machine tools, and wind power equipment, the precision requirements for gears have increased from the traditional level 6 to level 5 or even level 4, with tooth surface roughness needing to be controlled below Ra0.8μm. This poses stringent challenges to the clamping and drive systems of gear machining equipment.

[0003] Traditional gear machining clamping methods are mainly divided into two categories: one is center-mounted movement clamping, which relies on two centers at both ends to position the gear blank and drives the workpiece to rotate through a dial. However, this method has unavoidable positioning errors. The clearance between the center and the center hole can easily cause radial runout of the workpiece during high-speed rotation, and the axial positioning accuracy is greatly affected by the consistency of the center height, making it difficult to meet the requirements of high-precision grinding. The second method is the traditional drive sleeve clamping method, which fixes the workpiece through radial tension or axial pressure plate. Although it can achieve a certain degree of rigid clamping, uneven distribution of clamping force can easily cause micro-deformation of the gear blank, especially for thin-walled gear parts. Moreover, during high-speed grinding, when the linear speed exceeds 40m / s, the friction transmission between the drive sleeve and the workpiece is prone to relative slippage due to heat generation, resulting in a decrease in transmission accuracy. At the same time, frequent clamping operations require repeated manual calibration, which seriously restricts the efficiency of mass production.

[0004] With the widespread adoption of high-speed and high-efficiency grinding technology, the spindle speed of gear grinding machines has increased to over 3000 r / min. This significantly increases the instantaneous impact force between the grinding wheel and the workpiece, highlighting the insufficient dynamic stability of traditional clamping devices. In high-frequency vibration environments, the workpiece's positioning reference is prone to shift, leading to cumulative pitch error, excessive tooth direction error, and a high rework rate. Furthermore, existing clamping systems have a low level of automation and cannot seamlessly integrate with robotic loading and unloading systems in intelligent manufacturing production lines, thus restricting the overall production cycle of the processing unit. Utility Model Content

[0005] In view of the technical problems or one of the technical problems existing in the prior art, this utility model provides a high-precision gear grinding machine hydraulic automatic clamping drive device, including a drive seat, which is fixedly connected to the indexing plate of the gear grinding machine by a plurality of connecting screws. The characteristic is that the middle part of the drive seat extends upward to form a stepped cylindrical mandrel with a larger bottom and a smaller top, and a lower center is embedded at the top of the stepped cylindrical mandrel.

[0006] The stepped cylindrical mandrel is fitted with a cylindrical body. The inner cavity of the cylindrical body is a stepped cylindrical cavity that is larger at the bottom and smaller at the top. The height of the cavity in the larger diameter section is greater than the height of the larger diameter section of the stepped cylindrical mandrel, and the height of the cavity in the smaller diameter section is greater than the height of the smaller diameter section of the stepped cylindrical mandrel.

[0007] The lower part of the large-diameter section of the cylinder is sealed to the large-diameter section of the stepped cylindrical mandrel, while the small-diameter section of the cylinder is clearance-fitted to the small-diameter section of the stepped cylindrical mandrel.

[0008] The annular piston is disposed in two cavities: one is the cavity formed between the upper part of the large-diameter section of the cylinder and the small-diameter section of the stepped cylindrical mandrel; the other is the cavity formed between the small-diameter section of the cylinder and the small-diameter section of the stepped cylindrical mandrel.

[0009] A hydraulic expansion sleeve is installed in the upper cavity formed by the small-diameter section of the cylinder and the small-diameter section of the stepped cylindrical mandrel. The upper end of the annular piston abuts against the lower end of the hydraulic expansion sleeve.

[0010] The gear blank workpiece is positioned at the top of the lower center and clamped in the hydraulic expansion sleeve;

[0011] The lower end face of the drive seat is provided with an oil inlet and an oil return port. The drive seat and the cylinder are respectively provided with an oil inlet channel and an oil return channel. The two ends of the oil inlet channel are respectively connected to the oil inlet and the junction of the stepped cylindrical inner cavity of the cylinder. The two ends of the oil return channel are respectively connected to the oil return port and the junction of the stepped cylindrical mandrel.

[0012] Furthermore, the hydraulic expansion sleeve can generate radial expansion deformation when subjected to axial compression. It is a thin-walled sleeve structure with 6-12 evenly distributed opening slots along the axial direction. The width of the opening slot is 1-3mm and the length is 1 / 2-2 / 3 of the total length of the hydraulic expansion sleeve. The lower inner wall of the hydraulic expansion sleeve is tightly fitted with the outer wall of the small diameter section of the stepped cylindrical mandrel. The lower outer wall is clearance-fitted with the inner wall of the small diameter section cavity of the cylinder to form a hydraulic oil working cavity. The upper inner wall is provided with a circumferentially distributed micro-tooth structure, which is used to form an interference fit with the tooth blank workpiece and transmit torque.

[0013] Furthermore, hydraulic seals are provided between the annular piston and the inner wall of the large-diameter section of the cylinder, between the annular piston and the outer wall of the small-diameter section of the stepped cylindrical mandrel, and between the drive seat and the lower end mating surface of the cylinder; the hydraulic seals are combined seals made of nitrile rubber, wherein the annular piston and the cylinder use a Y-shaped lip seal, and the rest use a circular O-ring seal.

[0014] Furthermore, both the oil inlet channel and the oil return channel consist of two parts: one is an axial channel extending along the axis of the drive seat and the cylinder, and the other is a radial channel extending radially along the cylinder. The axes of the axial channel and the radial channel are perpendicular to each other and connected. The end of the radial channel away from the axial channel opens onto the circumferential surface of the cylinder and is sealed by an internal hexagonal tapered sealing screw. The tapered surface of the sealing screw is in sealing engagement with the tapered surface of the opening end of the radial channel.

[0015] Furthermore, the outer contour of the cylinder is a combination structure in which an upper truncated cone and a lower cylinder are coaxially connected. The small-diameter end of the truncated cone is located at the top and is adapted to the outer diameter of the small-diameter section of the cylinder cavity. The outer diameter of the cylinder is adapted to the outer diameter of the large-diameter section of the cylinder cavity. The overall outer contour shape is fitted to the inner cavity of the stepped cylinder that is larger at the bottom and smaller at the top.

[0016] Furthermore, the upper truncated cone of the cylinder has 3-6 countersunk holes evenly distributed circumferentially on its conical surface. The depth of the large diameter section of the countersunk hole is adapted to the head thickness of the fastening screw. The fastening screw is an internal hexagon countersunk screw, whose screw section passes through the countersunk hole and is screwed into the threaded hole pre-set on the upper end face of the drive seat, and the screw head is completely sunk into the countersunk hole.

[0017] Furthermore, a positioning hole is provided on the lower end face of the drive seat. The positioning hole is a blind hole and its diameter is in clearance fit with the diameter of the positioning pin on the indexing plate of the gear grinding machine. The clearance is 0.01-0.03mm, which is used for precise circumferential positioning of the drive seat and the indexing plate.

[0018] Furthermore, an upper center abuts against the upper center of the tooth blank workpiece. The axis of the upper center is collinear with the axis of the lower center, and the tip of the upper center is a conical structure with the same taper as the lower center, which is used to cooperate with the upper center hole of the tooth blank workpiece to form axial positioning.

[0019] The beneficial technical effects of this utility model are as follows:

[0020] 1. Improve positioning and clamping accuracy: The combination structure of the lower center and the hydraulic expansion sleeve achieves dual positioning of the gear blank workpiece. The lower center ensures the axial reference accuracy, and the hydraulic expansion sleeve achieves centering and clamping of the inner hole of the workpiece through radial uniform expansion. This reduces the positioning error of traditional clamping methods and effectively controls the radial runout of the workpiece to within 0.005mm, meeting the requirements of high-precision gear grinding for reference consistency.

[0021] 2. Optimized clamping force distribution: The hydraulic expansion sleeve adopts a thin-walled slotted structure, which generates uniform radial expansion under axial compression, so that the clamping force is evenly distributed along the circumference of the workpiece's inner hole, avoiding the micro-deformation of the workpiece caused by traditional rigid clamping. It is especially suitable for high-precision machining of thin-walled gear parts and reduces tooth profile errors caused by clamping stress.

[0022] 3. Enhanced dynamic stability: The nested structure of the stepped cylindrical mandrel and the cylinder forms a rigid support. Combined with the rigid transmission of the annular piston and the hydraulic expansion sleeve, it can maintain stable transmission accuracy even when rotating at high speeds above 3000 r / min, reducing the positioning reference offset caused by high-frequency vibration and reducing the cumulative pitch error and tooth direction error.

[0023] 4. Achieve automated clamping: Through hydraulic control of the oil inlet and return channels, the annular piston is driven to move axially and the hydraulic expansion sleeve automatically completes the clamping / unclamping action. It can be seamlessly connected with the robot loading and unloading system, eliminating manual calibration steps, improving batch production efficiency, and adapting to the cycle time requirements of intelligent manufacturing production lines.

[0024] 5. Compact structure and reliable sealing: The integrated oil circuit design and multi-stage sealing structure ensure the sealing fit between the cylinder and the spindle, and the hydraulic seal at the piston ensure the high efficiency and sealing of the hydraulic drive, avoiding high-pressure hydraulic oil leakage from affecting the grinding environment. At the same time, the compact stepped structure reduces the space occupied by the device and is suitable for the compact layout of the gear grinding machine.

[0025] 6. Combining centering and transmission functions: The micro-tooth structure of the hydraulic expansion sleeve not only achieves centering and clamping, but also reliably transmits torque through friction, avoiding the gap error of traditional dial transmission. Even when the linear speed exceeds 40m / s during high-speed grinding, it can still ensure transmission synchronization and improve the consistency of tooth surface machining quality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] Figure 2 yes Figure 1 A bottom view.

[0028] Figure 3 for Figure 2 A cross-sectional view at point AOA.

[0029] Figure 4 for Figure 2 Sectional view at the middle BOB. Detailed Implementation

[0030] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "communication" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0033] like Figure 1-4 As shown, a high-precision gear grinding machine hydraulic automatic clamping drive device includes a drive base 1, which is fixedly connected to the indexing plate of the gear grinding machine by six connecting screws 4. The middle part of the drive base 1 extends upward to form a stepped cylindrical mandrel 11 with a larger bottom and a smaller top. The top of the stepped cylindrical mandrel 11 is inlaid with a lower center point 5.

[0034] A cylindrical body 2 is sleeved on the outside of the stepped cylindrical mandrel 11. The inner cavity of the cylindrical body 2 is a stepped cylindrical cavity with a larger bottom and a smaller top. The height of the cavity with a larger diameter section is greater than the height of the cavity with a larger diameter section of the stepped cylindrical mandrel 11, and the height of the cavity with a smaller diameter section is greater than the height of the cavity with a smaller diameter section of the stepped cylindrical mandrel 11.

[0035] Among them, the lower part of the large-diameter section cavity of the cylinder 2 is sealed to the large-diameter section of the stepped cylindrical mandrel 11, and the small-diameter section cavity of the cylinder 2 is clearance-fitted to the small-diameter section of the stepped cylindrical mandrel 11.

[0036] The annular piston 3 is disposed in two cavities: one is the cavity formed between the upper part of the large-diameter section of the cylinder 2 and the small-diameter section of the stepped cylindrical mandrel 11; the other is the lower cavity formed between the small-diameter section of the cylinder 2 and the small-diameter section of the stepped cylindrical mandrel 11.

[0037] A hydraulic expansion sleeve 6 is installed in the upper cavity formed by the small diameter section of the cylinder 2 and the small diameter section of the stepped cylindrical mandrel 11. The upper end of the annular piston 3 abuts against the lower end of the hydraulic expansion sleeve 6.

[0038] The tooth blank workpiece 100 is positioned at the top of the lower center 5 and clamped in the hydraulic expansion sleeve 6;

[0039] The lower end face of the drive seat 1 is provided with an oil inlet 12 and an oil return port 13. The drive seat 1 and the cylinder 2 are respectively provided with an oil inlet channel 12a and an oil return channel 13a. The two ends of the oil inlet channel 12a are respectively connected to the junction of the oil inlet 12 and the stepped cylindrical inner cavity of the cylinder 2. The two ends of the oil return channel 13a are respectively connected to the junction of the oil return port 13 and the stepped cylindrical mandrel 11.

[0040] Working principle

[0041] This device is based on the principle of hydraulic drive. The pressure change of hydraulic oil drives the axial movement of a ring piston, which in turn pushes the hydraulic expansion sleeve to generate radial expansion, achieving automatic centering and clamping of the gear blank workpiece. Conversely, the return flow of hydraulic oil resets the piston, causing the expansion sleeve to elastically contract and release the workpiece. The core technology utilizes the pressure transmission characteristics of the hydraulic system to convert axial force into radial clamping force of the expansion sleeve. Combined with the positioning function of the lower center, this achieves high-precision clamping and stable transmission of the workpiece. The hydraulic expansion sleeve 6 used in this device is existing technology. Its core structure is a thin-walled sleeve with an axial opening, possessing the characteristics of uniform radial expansion under axial force and elastic contraction after the force is removed. It is widely used in centering and clamping scenarios in the machining field. This device mainly utilizes its existing structural characteristics, achieving engagement with the gear blank workpiece through the axial drive of the ring piston, without modifying its basic structure.

[0042] Work process

[0043] 1. Initial state: When the device is not supplied with hydraulic oil, the annular piston is in a low position under its own weight and the elastic force of the expansion sleeve. The hydraulic expansion sleeve is in a natural contraction state, and its inner diameter is slightly larger than the inner diameter of the tooth blank workpiece, which facilitates the insertion of the workpiece.

[0044] 2. Workpiece loading: The gear blank workpiece is placed on the outside of the hydraulic expansion sleeve, with the lower center hole fitting with the top of the lower center to achieve preliminary axial positioning.

[0045] 3. Clamping action:

[0046] - Hydraulic oil enters from the oil inlet 12 on the lower end face of the drive seat, and is transported through the oil inlet channel 12a to the junction of the stepped cylindrical inner cavity of the cylinder 2, and then flows into the cavity between the upper part of the large diameter section cavity of the cylinder and the small diameter section of the stepped cylindrical mandrel and the cavity between the lower part of the small diameter section cavity of the cylinder and the small diameter section of the stepped cylindrical mandrel.

[0047] - Hydraulic oil pressure pushes the annular piston 3 upward, and its upper end abuts against and axially compresses the hydraulic expansion sleeve 6;

[0048] -The hydraulic expansion sleeve 6 expands radially under axial compressive force. Due to its thin-walled structure with axial opening, its outer wall fits tightly with the inner hole of the gear blank 100, achieving centering and clamping. At the same time, the friction between the expansion sleeve and the workpiece can transmit torque to meet the rotation requirements during grinding.

[0049] 4. Grinding process: The indexing plate of the gear grinding machine drives the drive seat and the entire set of devices to rotate. The gear blank workpiece rotates synchronously with the device and completes the grinding of the tooth surface under the action of the grinding wheel. During this process, the lower center ensures the stability of the axial reference of the workpiece, and the radial clamping force of the expansion sleeve ensures that the workpiece has no radial runout, thus achieving high-precision machining.

[0050] 5. Releasing action:

[0051] - Stop the oil inlet and open the oil return passage. The hydraulic oil flows back from the "lower part of the small diameter section of the cylinder" through the oil return passage 13a to the oil return port 13.

[0052] - The annular piston 3 moves downward under the elastic restoring force of the expansion sleeve, releasing the axial compression on the expansion sleeve;

[0053] - The hydraulic expansion sleeve 6 elastically contracts, returning to its natural state and disengaging from the inner hole of the gear blank, allowing the machined workpiece to be removed.

[0054] In another preferred embodiment, the hydraulic expansion sleeve 6 can generate radial expansion deformation when subjected to axial compression. It is a thin-walled sleeve structure with 10 evenly distributed opening slots along the axial direction. The width of the opening slots is 1-3mm and the length is 1 / 2-2 / 3 of the total length of the hydraulic expansion sleeve 6. The lower inner wall of the hydraulic expansion sleeve 6 is closely fitted with the outer wall of the small diameter section of the stepped cylindrical mandrel 11. The lower outer wall is clearance-fitted with the inner wall of the small diameter section cavity of the cylinder 2 to form a hydraulic oil working cavity. The upper inner wall is provided with a circumferentially distributed micro-tooth structure for forming an interference fit with the tooth blank workpiece 100 and transmitting torque. In this preferred embodiment, the hydraulic expansion sleeve is designed with 10 evenly distributed opening slots and a specific size ratio to ensure more uniform radial expansion during axial compression. The tight fit between the lower section and the mandrel and the clearance fit with the cylinder form a stable hydraulic oil working cavity. The micro-tooth structure of the upper section enhances the friction with the tooth blank workpiece. While achieving reliable centering and clamping, it improves torque transmission efficiency and avoids workpiece slippage. It is especially suitable for the power transmission requirements during high-precision grinding.

[0055] In another preferred embodiment, hydraulic seals 7 are provided between the inner wall of the large-diameter section of the annular piston 3 and the inner wall of the large-diameter section of the cylinder 2, between the annular piston 3 and the outer wall of the small-diameter section of the stepped cylindrical mandrel 11, and between the lower end mating surface of the drive seat 1 and the cylinder 2. The hydraulic seals 7 are composite seals made of nitrile rubber, wherein a Y-shaped lip seal is used between the annular piston 3 and the cylinder 2, and O-rings with a circular cross-section are used for the others. The use of nitrile rubber composite seals between the annular piston and each component, the Y-shaped lip seal adapting to the dynamic sealing requirements of the annular piston, and the O-rings ensuring the static sealing of the mating surface between the drive seat and the cylinder, along with the multiple sealing design, effectively prevents hydraulic oil leakage, improves the pressure stability of the hydraulic system, extends the service life of the device, and adapts to high-pressure working environments.

[0056] In another preferred embodiment, both the oil inlet channel 12a and the oil return channel 13a are composed of two parts: one is an axial channel extending along the axis of the drive seat 1 and the cylinder 2, and the other is a radial channel extending radially along the cylinder 2. The axes of the axial channel and the radial channel are perpendicular to each other and connected. The end of the radial channel away from the axial channel opens onto the circumferential surface of the cylinder 2 and is sealed by an internal hexagonal tapered sealing screw 8. The tapered surface of the sealing screw 8 is in sealing engagement with the tapered surface of the opening end of the radial channel. The orthogonal axial and radial structure of the oil inlet and return channels facilitates manufacturing, and the tapered engagement of the internal hexagonal tapered sealing screw ensures reliable sealing, which not only ensures smooth oil passage and reduces pressure loss, but also facilitates disassembly and assembly during later maintenance, improving the sealing performance and maintenance convenience of the oil system.

[0057] In another preferred embodiment, the outer shape of the cylinder 2 is a combination structure of an upper truncated cone and a lower cylinder coaxially connected. The small-diameter end of the truncated cone is located at the top and matches the outer diameter of the small-diameter section of the cylinder 2 cavity. The outer diameter of the cylinder matches the outer diameter of the large-diameter section of the cylinder 2 cavity. The overall outer shape fits the inner cavity of the stepped cylinder, which is larger at the bottom and smaller at the top. In this preferred embodiment, the coaxial connection structure of the upper truncated cone and the lower cylinder not only matches the inner cavity of the stepped cylinder, achieving lightweight and enhanced structural rigidity, but also significantly reduces the radial dimension of the upper part of the cylinder by the design of the small-diameter end of the upper truncated cone. This effectively reduces spatial interference with the grinding wheel of the gear grinding machine. When the grinding wheel is close to the workpiece for grinding, the smaller upper size can reserve sufficient movement space for the grinding wheel, avoiding collision between the cylinder and the high-speed rotating grinding wheel. At the same time, it allows the grinding wheel to be processed closer to the root of the workpiece, expanding the size range of grindable gears, especially suitable for workpieces with a large tip circle diameter, and improving the applicability and flexibility of the device.

[0058] In another preferred embodiment, four circumferentially evenly distributed countersunk holes 21 are provided on the conical surface of the upper truncated cone of the cylinder 2 along the axial direction. The depth of the large-diameter section of the countersunk holes 21 is adapted to the head thickness of the fastening screw 9. The fastening screw 9 is an internal hexagon countersunk screw, whose screw section passes through the countersunk hole 26 and is screwed into the threaded hole pre-set on the upper end face of the drive seat 1, and the screw head is completely recessed into the countersunk hole 26. The four circumferentially evenly distributed countersunk holes on the cylinder, together with the internal hexagon countersunk screw, make the connection between the cylinder and the drive seat uniformly stressed. The screw head being completely recessed into the countersunk hole can avoid interference with other components, ensure the flatness of the device outline, and improve assembly safety and ease of operation.

[0059] In another preferred embodiment, a positioning hole 14 is formed on the lower end face of the drive seat 1. The positioning hole 14 is a blind hole, and its diameter is in clearance fit with the diameter of the positioning pin on the indexing plate of the gear grinding machine, with a clearance of 0.01-0.03mm. This clearance is used for precise circumferential positioning of the drive seat 1 and the indexing plate. The high-precision clearance fit of 0.01-0.03mm between the positioning hole of the drive seat and the positioning pin of the indexing plate enables precise circumferential positioning of both, reduces cumulative installation errors, ensures the coaxiality of the drive seat and the indexing plate, and lays the foundation for the consistency of the reference for subsequent workpiece processing.

[0060] In another preferred embodiment, an upper center 10 abuts against the upper center of the gear blank 100. The axis of the upper center 10 is collinear with the axis of the lower center 5, and the tip of the upper center 10 is a conical structure with the same taper as the lower center 5, used to cooperate with the upper center hole of the gear blank 100 to form axial positioning. The collinear design and consistent taper of the upper and lower centers can form bidirectional axial positioning for the gear blank, eliminate the axial movement space of the workpiece, ensure that the axis of the workpiece coincides with the rotation axis of the device, significantly reduce radial runout during machining, and improve the machining accuracy of gear tooth direction and pitch.

[0061] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high-precision gear grinding machine hydraulic automatic clamping drive device, comprising a drive base (1), wherein the drive base (1) is fixedly connected to the indexing plate of the gear grinding machine by a plurality of connecting screws (4), characterized in that, The middle part of the drive seat (1) extends upward to form a stepped cylindrical mandrel (11) that is larger at the bottom and smaller at the top, and the top of the stepped cylindrical mandrel (11) is inlaid with a lower center point (5). A cylindrical body (2) is sleeved on the outside of the stepped cylindrical mandrel (11). The inner cavity of the cylindrical body (2) is a stepped cylindrical inner cavity with a larger bottom and a smaller top. The height of the cavity of the larger diameter section is greater than the height of the larger diameter section of the stepped cylindrical mandrel (11), and the height of the cavity of the smaller diameter section is greater than the height of the smaller diameter section of the stepped cylindrical mandrel (11). Among them, the lower part of the large-diameter section cavity of the cylinder (2) is sealed with the large-diameter section of the stepped cylindrical mandrel (11), and the small-diameter section cavity of the cylinder (2) is clearance-fitted with the small-diameter section of the stepped cylindrical mandrel (11). The annular piston (3) is located in two cavities: one is the cavity formed between the upper part of the large-diameter section of the cylinder (2) and the small-diameter section of the stepped cylindrical mandrel (11); the other is the cavity formed between the small-diameter section of the cylinder (2) and the small-diameter section of the stepped cylindrical mandrel (11). A hydraulic expansion sleeve (6) is installed in the upper cavity formed between the small diameter section of the cylinder (2) and the small diameter section of the stepped cylindrical mandrel (11). The upper end of the annular piston (3) abuts against the lower end of the hydraulic expansion sleeve (6). The tooth blank workpiece (100) is positioned at the top of the lower center (5) and clamped in the hydraulic expansion sleeve (6); The lower end face of the drive seat (1) is provided with an oil inlet (12) and an oil return port (13). The drive seat (1) and the cylinder (2) are respectively provided with an oil inlet channel (12a) and an oil return channel (13a). The two ends of the oil inlet channel (12a) are respectively connected to the junction of the oil inlet (12) and the stepped cylindrical inner cavity of the cylinder (2). The two ends of the oil return channel (13a) are respectively connected to the junction of the oil return port (13) and the stepped cylindrical mandrel (11).

2. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, The hydraulic expansion sleeve (6) can generate radial expansion deformation when subjected to axial compression. It is a thin-walled sleeve structure with 6-12 evenly distributed opening slots along the axial direction. The width of the opening slot is 1-3mm and the length is 1 / 2-2 / 3 of the total length of the hydraulic expansion sleeve (6). The lower inner wall of the hydraulic expansion sleeve (6) is closely fitted with the outer wall of the small diameter section of the stepped cylindrical mandrel (11). The lower outer wall is clearance-fitted with the inner wall of the small diameter section cavity of the cylinder (2) to form a hydraulic oil working cavity. The upper inner wall is provided with a circumferentially distributed micro-tooth structure, which is used to form an interference fit with the tooth blank workpiece (100) and transmit torque.

3. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, Hydraulic seals (7) are provided between the inner wall of the large-diameter section of the annular piston (3) and the inner wall of the small-diameter section of the stepped cylindrical mandrel (11), and between the drive seat (1) and the lower end joint surface of the cylinder (2). The hydraulic seals (7) are combined seals made of nitrile rubber, wherein the annular piston (3) and the cylinder (2) use a lip seal with a Y-shaped cross section, and the rest use O-rings with a circular cross section.

4. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, The oil inlet channel (12a) and the oil return channel (13a) are both composed of two parts: one is an axial channel extending along the axis of the drive seat (1) and the cylinder (2), and the other is a radial channel extending along the radial direction of the cylinder (2); the axes of the axial channel and the radial channel are perpendicular to each other and connected. The end of the radial channel away from the axial channel opens onto the circumferential surface of the cylinder (2) and is sealed by an internal hexagonal tapered sealing screw (8). The tapered surface of the sealing screw (8) is sealed to the tapered surface of the opening end of the radial channel.

5. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, The outer shape of the cylinder (2) is a combination structure in which the upper truncated cone and the lower cylinder are coaxially connected. The small diameter end of the truncated cone is located at the top and is adapted to the outer diameter of the small diameter section cavity of the cylinder (2). The outer diameter of the cylinder is adapted to the outer diameter of the large diameter section cavity of the cylinder (2). The overall outer shape is fitted to the inner cavity of the stepped cylinder with the larger bottom and smaller top.

6. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 5, characterized in that, The upper part of the cylinder (2) has 3-6 countersunk holes (21) evenly distributed in the circumference on the conical surface of the cone. The depth of the large diameter section of the countersunk hole (21) is adapted to the head thickness of the fastening screw (9). The fastening screw (9) is an internal hexagon countersunk screw. Its screw section passes through the countersunk hole (21) and is screwed into the threaded hole preset on the upper end face of the drive seat (1). The screw head is completely sunk into the countersunk hole (21).

7. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, A positioning hole (14) is provided on the lower end face of the drive seat (1). The positioning hole (14) is a blind hole and its diameter is in clearance fit with the diameter of the positioning pin on the indexing plate of the gear grinding machine. The clearance is 0.01-0.03mm, which is used for precise circumferential positioning of the drive seat (1) and the indexing plate.

8. The high-precision gear grinding machine hydraulic automatic clamping drive device according to claim 1, characterized in that, The upper center of the tooth blank (100) is abutted by an upper center (10). The axis of the upper center (10) is collinear with the axis of the lower center (5), and the tip of the upper center (10) is a conical structure with the same taper as the lower center (5), which is used to cooperate with the upper center hole of the tooth blank (100) to form axial positioning.

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