A centerless grinding machine with precision feed transmission positioning device and positioning method

Abstract

The application discloses a centerless grinding machine with a precision feeding transmission positioning device and a positioning method, which can adjust the stretching of a ball screw in the bearing direction, effectively overcome the transmission error of the ball screw, and meet the requirements of high-end manufacturing industry on the precision part processing size tolerance accuracy. The application comprises the following: a driving servo motor is connected with a planetary reducer, the planetary reducer is installed on one side of a machine tool bed, the planetary reducer is connected with a ball screw, the ball screw is arranged in the machine tool bed, the other end of the ball screw is connected with a pre-stretching assembly, the pre-stretching assembly is used for realizing the stretching adjustment of the ball screw in the axis direction, overcoming the transmission error of the ball screw, a transmission nut seat is connected with the ball screw, a feeding moving sliding table is connected with the transmission nut seat, and the ball screw assembly cooperates with the transmission nut and the pre-stretching assembly and is used for controlling the precise feeding movement of the feeding moving sliding table on the machine tool bed.

Description

Technical Field

[0001] This application relates to the field of centerless grinding technology, and in particular to a centerless grinding machine and positioning method having a precision feed transmission positioning device. Background Technology

[0002] A centerless grinder is a machine tool that grinds without requiring the workpiece to be positioned along its axis, using a grinding wheel. Its working principle involves the grinding wheel rotating at high speed while a guide wheel rotates at a slower speed in the same direction, thus rotating the workpiece and achieving circumferential feed. During the grinding process, axial feed can be achieved by adjusting the tilt angle of the guide wheel axis, or radial feed can be achieved by moving the guide wheel head or grinding wheel head, depending on the machining requirements. Centerless grinders feature continuous machining, no tool retraction required, short workpiece clamping time, and high production efficiency, and are widely used in the field of precision parts machining.

[0003] In centerless grinding machines, to achieve high-precision grinding feed, a ball screw transmission system is typically used to drive the moving slide in reciprocating motion. Existing screw positioning structures generally adopt a "fixed + free" approach, meaning one end of the screw is firmly fixed while the other end is in a free state without any constraints. This results in uncontrollable ball screw deflection, limited feed accuracy, and insufficient machining stability. In high-precision machining, especially in scenarios requiring submicron dimensional tolerances, the grinding feed accuracy and stability are poor, failing to meet the dimensional tolerance requirements of high-end manufacturing for precision parts. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a centerless grinder with a precision feed transmission positioning device and a positioning method thereof.

[0005] The technical solution provided in this application is described below:

[0006] The first aspect of this application provides a centerless grinding machine with a precision feed transmission and positioning device, including: a feed slide, a machine bed, a ball screw, a transmission nut seat, a planetary reducer, a drive servo motor, and a pre-tensioning assembly;

[0007] The drive servo motor is connected to the planetary reducer, which is installed on one side of the machine tool bed. The planetary reducer is connected to the ball screw, which is located inside the machine tool bed. The other end of the ball screw is connected to the pre-tensioning assembly, which is used to adjust the ball screw in the axial direction to overcome the transmission error of the ball screw. The transmission nut seat is connected to the ball screw, and the feed slide is connected to the transmission nut seat. The ball screw assembly, together with the transmission nut seat and the pre-tensioning assembly, is used to control the feed slide to perform precise feed movement on the machine tool bed.

[0008] Optionally, the pre-tensioning assembly includes a positioning seat, a pre-tensioning adjusting screw, and a pre-tensioning bushing. The positioning seat is disposed on the machine tool bed and at the other end of the ball screw. The pre-tensioning bushing is mounted on the positioning seat, and the pre-tensioning adjusting screw is disposed on the pre-tensioning bushing. The pre-tensioning adjusting screw, in conjunction with the pre-tensioning bushing, is used to position the ball screw for transmission.

[0009] Optionally, at least three pretension adjusting screws are installed on the pretension bushing, and the at least three pretension adjusting screws are evenly distributed among each other.

[0010] Optionally, the positioning seat and the machine tool bed are connected by an integral molding.

[0011] Optionally, the drive end of the planetary reducer is connected to a transmission diaphragm coupling, which is mounted in a bearing housing.

[0012] Optionally, the bearing housing is mounted on the machine tool bed by bolts.

[0013] Optionally, the diaphragm coupling is connected to the ball screw positioning bearing via a lock nut.

[0014] Optionally, the ball screw is connected to the ball screw positioning bearing.

[0015] Optionally, the servo drive motor is detachably connected to the planetary reducer.

[0016] A second aspect of this application provides a positioning method for a centerless grinding machine having a precision feed drive positioning device. The positioning method is applied to the centerless grinding machine having the precision feed drive positioning device, and the method includes:

[0017] The axial stiffness Ks of the ball screw, the stiffness KN of the ball screw nut, the stiffness KB of the ball screw support bearing, and the axial stiffness KH of the nut and bearing mounting parts are obtained by load verification.

[0018] The stiffness of the ball screw is calculated according to the first formula;

[0019] The first formula is: 1 / Kτ=1 / ks+1 / KN+1 / KB+1 / KH, where Kτ is the stiffness of the ball screw, Ks is the axial stiffness of the ball screw, KN is the stiffness of the ball screw nut, KB is the ball screw support bearing, and KH is the axial stiffness of the nut and bearing mounting parts.

[0020] The axial load Fa of the ball screw is obtained through load verification.

[0021] The axial elastic displacement of the ball screw is calculated according to the second formula;

[0022] The second formula is: δ=Fa / Kτ, where δ is the axial elastic displacement of the ball screw, Fa is the axial load on the transmission screw system, and Kτ is the stiffness of the ball screw;

[0023] The preload of the ball screw is adjusted according to the axial elastic displacement of the ball screw.

[0024] As can be seen from the above technical solutions, this application has the following advantages:

[0025] The centerless grinding machine with a precision feed transmission and positioning device in this application is provided with a feed slide, a machine bed, a ball screw, a transmission nut seat, a planetary reducer, a drive servo motor, and a pre-tensioning assembly.

[0026] The drive servo motor is connected to a planetary reducer, which is installed on one side of the machine tool bed. The planetary reducer is connected to a ball screw, which is located inside the machine tool bed. The other end of the ball screw is connected to a pre-tensioning assembly, which is used to adjust the ball screw in the axial direction to overcome the transmission error of the ball screw. The transmission nut seat is connected to the ball screw, and the feed slide is connected to the transmission nut seat. The ball screw assembly, together with the transmission nut and the pre-tensioning assembly, is used to control the feed slide to make precise feed movements on the machine tool bed.

[0027] Furthermore, it can be seen that by setting a pre-tensioning component, the tension of the ball screw in the bearing direction can be adjusted, effectively overcoming the transmission error caused by the ball screw. This allows the ball screw to drive the feed slide to make precise feed movements on the machine tool bed through the transmission nut seat, resulting in strong grinding feed accuracy and stability, thus meeting the requirements of high-end manufacturing industry for the dimensional tolerance accuracy of precision parts processing. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a side view of the centerless grinding machine with a precision feed transmission positioning device according to this application.

[0030] Figure 2 for Figure 1 A sectional view of section AA;

[0031] Figure 3 This is a top view schematic diagram of the centerless grinding machine with a precision feed transmission positioning device according to this application;

[0032] Figure 4 This is a schematic diagram of the positioning method of the centerless grinder with a precision feed transmission positioning device according to this application;

[0033] In the diagram: 1. Feed slide; 2. Machine bed; 3. Ball screw; 4. Transmission nut seat; 5. Ball screw positioning bearing; 6. Planetary reducer; 7. Drive servo motor; 8. Bearing seat; 9. Transmission diaphragm coupling; 10. Locking nut; 11. Positioning seat; 12. Pretension adjusting screw; 13. Pretension bearing sleeve. Detailed Implementation

[0034] In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and other terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to describe the relative positional relationship between the components or parts and do not specifically limit the specific installation orientation of each component or part.

[0035] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0036] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0037] Furthermore, the structures, proportions, sizes, etc., drawn in the accompanying drawings of this application are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] In centerless grinding machines, to achieve high-precision grinding feed, a ball screw transmission system is typically used to drive the moving slide in reciprocating motion. Existing screw positioning structures generally adopt a "fixed + free" approach, meaning one end of the screw is firmly fixed while the other end is in a free state without any constraints. This results in uncontrollable ball screw deflection, limited feed accuracy, and insufficient machining stability. In high-precision machining, especially in scenarios requiring submicron dimensional tolerances, the grinding feed accuracy and stability are poor, failing to meet the dimensional tolerance requirements of high-end manufacturing for precision parts.

[0040] Based on this, this application provides a centerless grinding machine with a precision feed transmission positioning device. By setting a pre-tensioning component, the tension of the ball screw in the bearing direction can be adjusted, effectively overcoming the transmission error caused by the ball screw. This allows the ball screw to drive the feed slide to make precise feed movements on the machine tool bed through the transmission nut seat. The grinding feed accuracy and stability are strong, thus meeting the requirements of high-end manufacturing industry for the dimensional tolerance accuracy of precision parts processing.

[0041] Please see Figures 1 to 3The first aspect of this application provides a centerless grinding machine with a precision feed transmission and positioning device, including: a feed slide 1, a machine bed 2, a ball screw 3, a transmission nut seat 4, a ball screw positioning bearing 5, a planetary reducer 6, a drive servo motor 7, and a pre-tensioning assembly;

[0042] The drive servo motor 7 is connected to the planetary reducer 6, which is installed on one side of the machine tool bed 2. The planetary reducer 6 is connected to the ball screw 3, which is located inside the machine tool bed 2. The other end of the ball screw 3 is connected to the pre-tensioning assembly, which is used to adjust the ball screw 3 in the axial direction to overcome the transmission error of the ball screw 3. The transmission nut seat 4 is connected to the ball screw 3, and the feed slide 1 is connected to the transmission nut seat 4. The ball screw 3 assembly, together with the transmission nut seat 4 and the pre-tensioning assembly, is used to control the feed slide 1 to perform precise feed movement on the machine tool bed 2.

[0043] First, let's introduce the functions of each component:

[0044] Detailed explanation of the principles behind the functions of each component

[0045] The drive servo motor 7 is the power source of the centerless grinder, which controls the output torque and speed. It drives the planetary reducer 6 to rotate. Under the action of the planetary reducer 6, the feed slide 1 moves on the machine bed 2 through the ball screw 3 and the transmission nut seat 4.

[0046] The servo motor integrates feedback devices such as encoders or Hall sensors, which can monitor the motor's position, speed, and acceleration in real time. The controller enables precise control of the motor's output characteristics. When a control command is received, the servo motor adjusts its output torque and speed according to the command requirements, thereby driving the subsequent transmission components.

[0047] Planetary reducer 6: Planetary reducer 6 is used to reduce the output speed of the drive servo motor 7 and increase the output torque, thereby improving the accuracy and stability of the transmission system.

[0048] The planetary reducer 6 contains components such as a sun gear, planet gears, and a ring gear. When the servo motor 7 rotates, the sun gear drives the planet gears to rotate on their own axes and revolve around the sun gear. The planet gears then transmit power to the ball screw 3 through the ring gear. Due to the presence of the planet gears, the reducer can achieve a high speed ratio reduction and amplify the torque of the motor in the process. In addition, the multi-tooth meshing characteristic of the planetary reducer 6 helps to reduce vibration and noise during transmission and improve transmission accuracy.

[0049] Ball screw 3: Used to convert rotary motion into linear motion, driving the feed slide 1 for precision feeding.

[0050] The ball screw 3 consists of a screw and a nut. Balls are installed inside the nut and roll along the spiral grooves of the screw. When the screw rotates, the balls roll within the spiral grooves and push the nut to move axially along the screw. Because the rolling friction resistance between the balls and the spiral grooves is much smaller than the sliding friction resistance, the ball screw 3 features high efficiency, high precision, and low wear. Furthermore, the ball screw 3 also has high rigidity and load-bearing capacity, meeting the requirements of precision machining.

[0051] Transmission nut seat 4: Transmission nut seat 4 is used to connect ball screw 3 and feed slide 1, and transmits the linear motion of ball screw 3 to feed slide 1 so that feed slide 1 can move on machine tool bed 2.

[0052] The transmission nut seat 4 contains a nut and balls that match the ball screw 3. When the ball screw 3 rotates, the nut moves along the screw axis under the push of the balls. The transmission nut seat 4 is fixed to the feed slide 1 by bolts or other connection methods. Therefore, when the nut moves, it will drive the slide to move together.

[0053] Pre-tensioning assembly: Pre-tensioning adjustment of ball screw 3 to achieve tension adjustment of ball screw 3 in the axial direction and overcome transmission error of ball screw 3.

[0054] Feed slide 1: It carries the workpiece or grinding tool and performs precise linear feed motion on the machine tool bed 2.

[0055] The feed slide 1 is connected to the machine bed 2 via guide rails and sliders, forming a stable linear motion pair. When the ball screw 3 drives the transmission nut seat 4 to move, it will further drive the feed slide 1 to move on the machine bed 2.

[0056] The overall working principle of the centerless grinder in this application is as follows:

[0057] This application's centerless grinding machine achieves precise feeding and positioning of the workpiece or grinding tool by integrating a high-precision transmission system and a pre-tensioning assembly. At startup, the drive servo motor 7 starts and drives the planetary reducer 6 to rotate. The planetary reducer 6 converts the motor's high-speed, low-torque output into a low-speed, high-torque output, which is then transmitted to the ball screw 3. Under the action of the transmission nut seat 4, the ball screw 3 converts the rotational motion into linear motion, pushing the feed slide 1 to perform precise linear feed on the machine bed 2. Simultaneously, the pre-tensioning assembly pre-tensions and adjusts the ball screw 3, ensuring stable accuracy and stability during transmission. This tensioning adjustment of the ball screw 3 in the axial direction overcomes transmission errors and achieves accurate axial position control, enabling the entire centerless grinding machine to achieve high-precision feed transmission and positioning, meeting the machining accuracy requirements of a centerless grinding machine.

[0058] Optionally, the pre-tensioning assembly includes a positioning seat 11, a pre-tensioning adjusting screw 12, and a pre-tensioning bushing. The positioning seat 11 is disposed on the machine tool bed 2 and at the other end of the ball screw 3. The pre-tensioning bushing is mounted on the positioning seat 11, and the pre-tensioning adjusting screw 12 is disposed on the pre-tensioning bushing. The pre-tensioning adjusting screw 12 cooperates with the pre-tensioning bushing to perform transmission positioning of the ball screw 3.

[0059] In this embodiment, the pre-tensioning assembly is a key component in the centerless grinder used to improve the transmission accuracy and stability of the ball screw 3. The pre-tensioning assembly includes three parts: a positioning seat 11, a pre-tensioning adjusting screw 12, and a pre-tensioning bushing.

[0060] The positioning seat 11 is the basic support component of the pre-tensioning assembly, used to securely install the pre-tensioning assembly onto the machine tool bed 2. The positioning seat 11 provides an installation reference, ensuring that the pre-tensioning bushing and the pre-tensioning adjusting screw 12 can be accurately aligned with the ball screw 3 and apply preload. Furthermore, the positioning seat 11 and the machine tool bed 2 are integrally formed, meaning the connection between the positioning seat 11 and the machine tool bed 2 is non-removable. This creates a stable working platform, ensuring that it will not move or deform due to vibration or external forces during long-term operation.

[0061] Pre-tensioned bushing: The pre-tensioned bushing is installed on the positioning seat 11 to support and position the other end of the ball screw 3. It fits with the ball screw 3 through a precisely machined inner hole to ensure that the ball screw 3 maintains the correct axial position during transmission.

[0062] The inner diameter and shape of the pre-tensioned bushing are precision machined to match the outer diameter and shape of the ball screw 3. When the ball screw 3 is inserted into the inner hole of the bushing, the fit clearance between the two is extremely small, thereby achieving high-precision axial positioning. In addition, the bushing also has a certain rigidity, which can resist axial deformation caused by preload.

[0063] Pretension adjusting screw 12: The pretension adjusting screw 12 is used to adjust the pretension of the ball screw 3. By rotating the adjusting screw, the clamping force on the pretension bushing can be changed, thereby applying a certain pretension force to the ball screw 3.

[0064] The pretension adjusting screw 12 typically has fine threads for precise adjustment. When the adjusting screw is rotated, its end presses against the pretension bushing and transmits the pretension force to the ball screw 3 through the bushing. The magnitude of the pretension force can be controlled by rotating the adjusting screw by the number of turns or by the torque to achieve the required transmission accuracy and stability.

[0065] The ball screw 3 is pre-stretched and adjusted by the pre-stretching assembly to ensure that the feed slide 1 can move accurately, thereby improving the machining accuracy and stability of the centerless grinder.

[0066] Optionally, at least three pretension adjusting screws 12 are installed on the pretension bushing, and the at least three pretension adjusting screws 12 are evenly distributed among each other.

[0067] In this embodiment, at least three pretension adjusting screws 12 are installed on the pretension bushing. Preferably, three screws are used, but more may also be used. This embodiment does not impose a specific limitation and can be set according to actual conditions. Furthermore, the equal spacing between these pretension adjusting screws 12 ensures that the ball screw 3 experiences more uniform force in all directions when subjected to preload, helping to prevent bending or deformation of the ball screw 3 due to uneven force, thereby improving transmission accuracy.

[0068] Furthermore, the synergistic effect of multiple adjusting screws can significantly enhance the overall stability of the pre-tensioned assembly. Even if one screw is slightly loosened due to external force, the other screws can still maintain sufficient preload to prevent the ball screw 3 from displacing or vibrating.

[0069] With multiple adjusting screws, more adjustment points are provided, making it more flexible and precise to adjust the preload. By rotating different adjusting screws, the force on the ball screw 3 in various directions can be finely adjusted to achieve a better positioning effect.

[0070] Optionally, the drive end of the planetary reducer 6 is connected to the transmission diaphragm coupling 9, which is installed in the bearing housing 8, and the bearing housing 8 is bolted to the machine tool bed 2.

[0071] In this embodiment, the planetary reducer 6 converts the high-speed, low-torque output of the motor into a low-speed, high-torque output. The diaphragm coupling 9 is a highly elastic, high-torque-capacity, and long-life coupling used to connect the output shafts of the two planetary reducers 6 and the ball screw 3. It allows for certain axial, radial, and angular misalignment and consists of a metal diaphragm and two half-couplings. The diaphragm absorbs vibration and impact while transmitting torque. In the centerless grinder, the diaphragm coupling 9 serves to buffer, dampen, and compensate for installation errors, protecting the transmission components from damage caused by vibration and impact.

[0072] By connecting the drive end of the planetary reducer 6 to the diaphragm coupling 9, efficient and stable transmission of motor power is achieved. The diaphragm coupling 9 is installed in the bearing housing 8, which not only ensures its stable operation, but also absorbs vibration and impact during transmission through its high elasticity. The bearing housing 8 is firmly installed on the machine tool bed 2 with bolts, providing good stability and support.

[0073] Furthermore, it can be seen that the high elasticity of the diaphragm coupling 9 effectively absorbs vibration and impact during the transmission process, protecting the transmission components. The tight connection of the bearing housing 8 and bolts ensures the stability and reliability of the transmission process, prevents loosening and displacement of components, and provides a strong guarantee for the high-precision and high-efficiency machining of machine tools.

[0074] Optionally, the diaphragm coupling 9 is connected to the ball screw positioning bearing 5 via a lock nut 10, and the ball screw 3 is connected to the ball screw positioning bearing 5.

[0075] In this embodiment, the ball screw positioning bearing 5 is used to fix one end of the ball screw 3, ensuring that the ball screw 3 maintains the correct axial position during transmission. Simultaneously, it can withstand the radial and axial forces generated by the ball screw 3 during transmission. The locking nut 10 is used to tightly connect the transmission diaphragm coupling 9 and the ball screw positioning bearing 5 together, securing the two components firmly with preload to prevent loosening or displacement during transmission. Therefore, the presence of the locking nut 10 ensures the reliability of the connection between the various components of the transmission system, which is an important guarantee for the stable operation of the centerless grinder.

[0076] By connecting the diaphragm coupling 9 to the ball screw positioning bearing 5 via the lock nut 10, efficient and stable power transmission from the planetary reducer 6 to the ball screw 3 is achieved. Simultaneously, the ball screw positioning bearing 5 ensures the axial stability of the ball screw 3 during transmission, while the lock nut 10 guarantees the tightness between the connecting components.

[0077] Optionally, the servo drive motor and the planetary reducer 6 are detachably connected, which facilitates disassembly and installation when the servo drive motor or the planetary reducer 6 needs to be repaired or replaced.

[0078] Please see Figure 4 The second aspect of this application provides a positioning method for a centerless grinder with a precision feed drive positioning device. The positioning method is applied to the centerless grinder with the precision feed drive positioning device, and the method includes:

[0079] 101. Obtain the axial stiffness Ks of the ball screw, the stiffness KN of the ball screw nut, the stiffness KB of the ball screw support bearing, and the axial stiffness KH of the nut and bearing mounting parts by measurement.

[0080] 102. Calculate the stiffness of the ball screw according to the first formula;

[0081] 103. The first formula: 1 / Kτ=1 / ks+1 / KN+1 / KB+1 / KH, where Kτ is the stiffness of the ball screw, Ks is the axial stiffness of the ball screw, KN is the stiffness of the ball screw nut, KB is the ball screw support bearing, and KH is the axial stiffness of the nut and bearing mounting part.

[0082] 104. Load verification to obtain the axial load Fa of the ball screw;

[0083] 105. Calculate the axial elastic displacement of the ball screw according to the second formula;

[0084] 106. The second formula is: δ=Fa / Kτ, where δ is the axial elastic displacement of the ball screw, Fa is the axial load on the transmission screw system, and Kτ is the stiffness of the ball screw;

[0085] 107. Adjust the pretension of the ball screw according to the axial elastic displacement of the ball screw.

[0086] In this embodiment, the stiffness of the ball screw and its axial elastic displacement under actual load are determined by precise measurement and calculation. Based on this, the preload of the ball screw is adjusted to achieve tension adjustment of the ball screw in the axial direction, thus overcoming the transmission error of the ball screw.

[0087] By measuring the stiffness of the ball screw and its related components, and using the first formula for comprehensive calculation, the precise stiffness value of the ball screw as a whole can be obtained, which helps to more accurately understand the deformation characteristics of the ball screw under stress.

[0088] Based on the known ball screw stiffness and actual axial load, the axial elastic displacement of the ball screw under load can be calculated using the second formula. According to the calculated axial elastic displacement, the pretension of the ball screw can be adjusted more specifically. Appropriate pretension can effectively reduce the elastic deformation of the ball screw under load, thereby improving the rigidity and positioning accuracy of the transmission and reducing errors and instabilities caused by deformation.

[0089] It should be noted that the above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A positioning method for a centerless grinder with a precision feed drive positioning device, the positioning method being applied to a centerless grinder with a precision feed drive positioning device, characterized in that, The method includes: The axial stiffness Ks of the ball screw, the stiffness KN of the ball screw nut, the stiffness KB of the ball screw support bearing, and the axial stiffness KH of the nut and bearing mounting parts are obtained by measurement. The stiffness of the ball screw is calculated according to the first formula; The first formula is: 1 / Kτ=1 / ks+1 / KN+1 / KB+1 / KH, where Kτ is the stiffness of the ball screw, Ks is the axial stiffness of the ball screw, KN is the stiffness of the ball screw nut, KB is the ball screw support bearing, and KH is the axial stiffness of the nut and bearing mounting parts. The axial load Fa of the ball screw is obtained through load verification. The axial elastic displacement of the ball screw is calculated according to the second formula; The second formula is: δ=Fa / Kτ, where δ is the axial elastic displacement of the ball screw, Fa is the axial load on the transmission screw system, and Kτ is the stiffness of the ball screw. The preload of the ball screw is adjusted according to the axial elastic displacement of the ball screw.

2. A centerless grinding machine applied to the positioning method of claim 1, characterized in that, include: Feed slide, machine tool bed, ball screw, transmission nut seat, planetary reducer, drive servo motor and pre-tensioning assembly; The drive servo motor is connected to the planetary reducer, which is installed on one side of the machine tool bed. The planetary reducer is connected to the ball screw, which is located inside the machine tool bed. The other end of the ball screw is connected to the pre-tensioning assembly, which is used to adjust the ball screw in the axial direction to overcome the transmission error of the ball screw. The transmission nut seat is connected to the ball screw, and the feed slide is connected to the transmission nut seat. The ball screw assembly, together with the transmission nut seat and the pre-tensioning assembly, is used to control the feed slide to perform precise feed movement on the machine tool bed.

3. The centerless grinding machine according to claim 2, characterized in that, The pre-tensioning assembly includes a positioning seat, a pre-tensioning adjusting screw, and a pre-tensioning bushing. The positioning seat is disposed on the machine tool bed and at the other end of the ball screw. The pre-tensioning bushing is mounted on the positioning seat, and the pre-tensioning adjusting screw is disposed on the pre-tensioning bushing. The pre-tensioning adjusting screw, in conjunction with the pre-tensioning bushing, is used to perform transmission positioning of the ball screw.

4. The centerless grinding machine according to claim 3, characterized in that, At least three pretension adjusting screws are installed on the pretension bushing, and the at least three pretension adjusting screws are evenly distributed between each other.

5. The centerless grinding machine according to claim 3, characterized in that, The positioning seat is integrated with the machine tool bed.

6. The centerless grinding machine according to claim 2, characterized in that, The drive end of the planetary reducer is connected to a transmission diaphragm coupling, which is installed in a bearing housing.

7. The centerless grinding machine according to claim 6, characterized in that, The bearing housing is mounted on the machine tool bed by bolts.

8. The centerless grinding machine according to claim 7, characterized in that, The diaphragm coupling is connected to the ball screw positioning bearing via a lock nut.

9. The centerless grinding machine according to claim 8, characterized in that, The ball screw is connected to the ball screw positioning bearing.

10. The centerless grinding machine according to any one of claims 2 to 9, characterized in that, The drive servo motor is detachably connected to the planetary reducer.

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