Positioning fixture, boring machine and positioning method

Abstract

This application relates to the field of machine tool fixture technology, specifically disclosing a positioning fixture, a boring machine tool, and a positioning method. The positioning fixture includes a worktable and multiple clamping mechanisms. A fixture hole is formed on the worktable, and a first channel is formed within the worktable, through which a first airflow flows. A first detection element is placed within the first channel, and a first outlet is located on the worktable. A workpiece is placed on the worktable, and each first outlet is sealed. A second channel is formed within the pneumatic gripper, through which a second airflow flows. A second outlet is located on the clamping end face, which is used to contact the workpiece to seal the second outlet. A leakage detection element detects the leakage amount at the second outlet. A controller adjusts the opening of a pneumatic proportional valve to regulate the clamping force of the pneumatic gripper. By monitoring the leakage amount in the contact area between the clamping end face and the workpiece, the tightness of the clamping is determined, thereby enabling adaptive control of the clamping force by dynamically adjusting the pneumatic proportional valve through the controller.

Description

Technical Field

[0001] This application relates to the field of machine tool fixture technology, and in particular to a positioning fixture, a boring machine tool and a positioning method. Background Technology

[0002] In the field of machining, boring is a key process for high-precision hole machining and is widely used in the manufacturing of core components such as engine blocks, gearbox housings, and hydraulic valve blocks. The precision of boring directly determines the assembly accuracy, motion stability, and service life of the components, while the performance of the boring machine tool fixture, as a device for workpiece positioning and clamping, directly affects machining accuracy, production efficiency, and machining costs.

[0003] Currently, to meet the production needs of various product models, boring machines generally use universal positioning fixtures, which mostly employ multi-point clamping. During clamping and positioning, because the force applied by the positioning fixture remains constant, when used for different models of compressor bearings, the mismatch in clamping force can easily lead to slight deformation of the bearing, affecting the machining accuracy of the compressor bearing's inner bore. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a positioning fixture, a boring machine tool, and a positioning method.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] According to one aspect of this application, a positioning fixture is provided, comprising:

[0007] A workbench has a fixture hole and multiple first channels. A first airflow flows through the first channel and a first detection element is provided in the first channel to detect the flow of the first airflow. The first outlet of each first channel is evenly opened on the workbench along the circumference of the fixture hole. The workbench is used to place workpieces and to close each first outlet through the workpieces.

[0008] Multiple clamping mechanisms are evenly spaced along the circumference of the clamping hole. Each clamping mechanism includes a pneumatic gripper, a pneumatic proportional valve, a leak detection element, and a controller. Each pneumatic gripper reciprocates radially along the clamping hole. A second channel is provided inside the pneumatic gripper, and a second airflow flows through the second channel. The second outlet of the second channel is located on the clamping end face of the pneumatic gripper. The clamping end face is used to contact the workpiece to close the second outlet through the workpiece.

[0009] The air leakage detection device is used to detect the amount of air leakage at the second outlet. The controller adjusts the opening of the pneumatic proportional valve according to the amount of air leakage to adjust the clamping force of the pneumatic gripper.

[0010] In one embodiment, the workbench is further provided with a plurality of positioning seats evenly spaced along the circumference of the fixture hole. Each positioning seat has a third channel. The third entrance of each third channel is connected to each of the first exits. The third exit of each third channel is opened on the top surface of each positioning seat. The workpiece is placed on the top surface to close the third exit.

[0011] In one embodiment, the third outlet is located at the center of the top surface, and at least one groove is provided on the top surface. The groove is located on the top surface along the height direction of the positioning seat, and the two ends of the groove are open along the extension direction of the groove.

[0012] In one embodiment, the pneumatic gripper is further provided with a negative pressure adsorption element, which is connected to the second channel and is used to provide negative pressure to the second outlet to limit and fix the workpiece between each of the pneumatic grippers.

[0013] According to another aspect of this application, a boring machine tool is also provided, including the positioning fixture described above.

[0014] In one embodiment, the system further includes a feeding mechanism and a rotary feeding mechanism, the rotary feeding mechanism comprising:

[0015] Activity platform;

[0016] At least one set of transfer clamps is provided on the movable table. The transfer clamps include two spaced-apart transfer jaws, which correspond to the loading position of the loading mechanism and the worktable, respectively, and are used to transfer the workpiece between the loading position and the worktable.

[0017] A rotation drive assembly is used to drive the rotation of the movable platform;

[0018] A lifting drive assembly is used to drive the lifting and lowering of the movable platform.

[0019] According to another aspect of this application, a positioning method is also provided, applied to the positioning fixture described above, the method comprising:

[0020] A first airflow is continuously introduced into the first channel, the workpiece is placed on the workbench, the first outlet of each of the first channels is closed, and the placement state of the workpiece is determined according to the flow of the first airflow.

[0021] After the workpiece is stably attached to the worktable, each of the pneumatic grippers is controlled to move synchronously to hold the workpiece.

[0022] The leakage rate at the second outlet is detected, and the opening of the pneumatic proportional valve is adjusted according to the leakage rate to control the clamping force of the pneumatic gripper within a threshold range.

[0023] In one embodiment, placing the workpiece on the worktable includes:

[0024] The workpiece is placed on a plurality of positioning seats arranged at intervals. During the placement of the workpiece, the first airflow is blown out through the third outlet on the positioning seat, pressed down by the workpiece and guided to the mating gap between the workpiece and the positioning seat, blowing out foreign objects in the mating gap.

[0025] In one embodiment, while detecting the leakage amount at the second outlet, adjusting the opening of the pneumatic proportional valve and the clamping force of the pneumatic gripper based on the leakage amount to control the leakage amount within a threshold range, the method further includes:

[0026] The physical parameters of the second channel are monitored, and a dynamic parameter curve is generated that varies over time. The physical parameters include air pressure or airflow rate.

[0027] The dynamic parameter curve is compared with multiple standard feature curves, each of which corresponds to a workpiece model.

[0028] Based on the comparison results, the model of the workpiece currently being clamped is identified.

[0029] In one embodiment, it further includes:

[0030] Before the workpiece is precision machined, the clamping force of the pneumatic gripper is reduced and a negative pressure is generated at the second outlet, thereby generating a negative pressure adsorption force between the clamping end face and the workpiece.

[0031] The workpiece is precision machined while the second outlet is kept under negative pressure.

[0032] According to the positioning fixture, boring machine tool, and positioning method provided in the embodiments of this application, the placement of the workpiece is determined by monitoring the sealing of the first airflow within the positioning seat. When the workpiece is clamped and fixed, the air leakage in the contact area between the clamping end face and the workpiece is monitored to determine the clamping tightness. Based on this, the pneumatic proportional valve is dynamically adjusted by the controller to achieve adaptive control of the clamping force, effectively preventing workpiece deformation while ensuring workpiece fixation. This solves the problem that traditional fixtures, due to their fixed clamping force, easily cause slight deformation of the workpiece when clamping different types of compressor bearings, thus affecting the machining accuracy of its inner hole. Attached Figure Description

[0033] Figure 1 This diagram shows an overall structural schematic of a positioning fixture provided in an embodiment of this application.

[0034] Figure 2 This diagram illustrates the usage state of a positioning fixture for placing a workpiece, as provided in an embodiment of this application.

[0035] Figure 3 Show Figure 2 The main view;

[0036] Figure 4 This illustration shows another structural diagram of a positioning fixture provided in an embodiment of this application;

[0037] Figure 5 Show Figure 4 Enlarged view of section A in the middle;

[0038] Figure 6 Show Figure 4 Enlarged view of section B;

[0039] Figure 7 This illustration shows a structural schematic diagram of a boring machine tool provided in an embodiment of this application;

[0040] Figure 8 This document illustrates a flowchart of a positioning method provided in an embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Workbench; 2. Fixture hole; 3. Clamping mechanism; 4. Pneumatic gripper; 5. Second outlet; 6. Clamping end face; 7. Positioning seat; 8. Third outlet; 9. Top surface; 10. Groove; 11. Movable table; 12. Transfer fixture; 13. Transfer gripper; 14. Lifting drive assembly; 100. Workpiece. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0045] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0046] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "lateral," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the purpose of simplifying the description. They 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, and therefore should not be construed as limiting this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] like Figures 1-6 As shown, this embodiment provides a positioning fixture, which includes a worktable 1 and multiple clamping mechanisms 3.

[0048] The workbench 1 has a fixture hole 2 and a plurality of first channels are also provided inside the workbench 1. A first airflow flows through the first channel and a first detection element is also provided in the first channel to detect the flow of the first airflow. The first outlet of each first channel is evenly opened on the workbench 1 along the circumference of the fixture hole 2. The workbench 1 is used to place the workpiece 100 and to close each first outlet through the workpiece 100.

[0049] With uniformly distributed first outlets, when workpiece 100 is placed on worktable 1, all first outlets can be closed simultaneously, thereby changing the flow state of the first airflow. A first detection element monitors the changes in the first airflow in real time to determine whether workpiece 100 completely covers all first outlets, thus ensuring the accuracy and stability of workpiece 100's placement and avoiding processing errors caused by misalignment. Simultaneously, when workpiece 100 closes all first outlets, it also ensures a tight fit between workpiece 100 and worktable 1, preventing debris from entering between them and ensuring the subsequent processing accuracy of workpiece 100.

[0050] The first detection device can be at least one of a barometric pressure sensor, an airflow sensor, a wind speed sensor, or a sound sensor, and the change in the detection signal is used to determine whether the airflow in the first channel is flowing.

[0051] Multiple clamping mechanisms 3 are evenly spaced along the circumference of the clamping hole 2. Each clamping mechanism 3 includes a pneumatic gripper 4, a pneumatic proportional valve, a leak detection element, and a controller. Each pneumatic gripper 4 moves reciprocally along the radial direction of the clamping hole 2. A second channel is provided in the pneumatic gripper 4, and a second airflow flows through the second channel. The second outlet 5 of the second channel is opened on the clamping end face 6 of the pneumatic gripper 4. The clamping end face 6 is used to contact the workpiece 100 so as to close the second outlet 5 through the workpiece 100.

[0052] The pneumatic gripper 4, which moves radially and reciprocally, can clamp the workpiece 100 uniformly in the circumference, ensuring a symmetrical distribution of clamping force. The second outlet 5 is opened on the clamping end face 6. When the clamping end face 6 contacts the workpiece 100, the second outlet 5 is closed, and the flow state of the second airflow changes, thereby ensuring stable clamping of the pneumatic gripper 4 and the workpiece 100.

[0053] The air leakage detection device is used to detect the amount of air leakage at the second outlet 5. The controller adjusts the opening of the pneumatic proportional valve according to the amount of air leakage to adjust the clamping force of the pneumatic gripper 4.

[0054] By monitoring the air leakage at the second outlet 5 in real time, the tightness of contact between the clamping end face 6 and the workpiece 100 can be indirectly reflected. When the air leakage is too large, it indicates insufficient clamping force. The controller increases the opening of the pneumatic proportional valve to increase the clamping force, and vice versa. In addition, when the clamping force is too large, it will cause deformation of the workpiece 100. The air leakage at the second outlet 5 will show a trend of first decreasing and then increasing. After the signal is transmitted to the controller, the controller recognizes that the clamping force is too large and then decreases the opening of the pneumatic proportional valve to reduce the clamping force. This achieves adaptive clamping of the workpiece 100, which can not only ensure the clamping and fixing effect of the workpiece 100, but also effectively avoid the problem of deformation of the workpiece 100 due to excessive clamping force, which would affect subsequent processing.

[0055] like Figures 1-6 As shown, in some embodiments, the workbench 1 is further provided with a plurality of positioning seats 7 evenly spaced along the circumference of the fixture hole 2. Each positioning seat 7 has a third channel. The third entrance of each third channel is connected to each of the first exits. The third exit 8 of each third channel is opened on the top surface 9 of each positioning seat 7. The workpiece 100 is disposed on the top surface 9 to close the third exit 8.

[0056] By setting a positioning seat 7 on the worktable 1 and placing the workpiece 100 on the positioning seat 7, the contact area between the workpiece 100 and the positioning fixture can be reduced, thereby reducing the possibility of foreign objects between the workpiece 100 and the positioning fixture and avoiding the situation where the workpiece 100 is crushed by foreign objects.

[0057] The third channel on the positioning seat 7 connects with the first channel, allowing the first airflow to flow to the top surface 9 of the positioning seat 7 and be sealed by the workpiece 100. Therefore, when the workpiece 100 is placed on the positioning seat 7, the third outlet 8 is closed, and the flow state of the first airflow changes. The first detection element is used to detect this change in the flow state of the first airflow, thereby determining whether the workpiece 100 is stably placed on the positioning seat 7 and whether there is no gap between it and the positioning seat 7.

[0058] Optionally, three positioning seats 7 are provided, and the three positioning seats 7 are evenly spaced around the circumference of the clamp hole 2.

[0059] Furthermore, the third outlet 8 is located at the center of the top surface 9, and at least one groove 10 is provided on the top surface 9. The groove 10 is provided on the top surface 9 along the height direction of the positioning seat 7, and the two ends of the groove 10 are open along the extension direction of the groove 10.

[0060] By positioning the third outlet 8 at the center of the top surface 9, the airflow in the third channel is reliably cut off only when the workpiece 100 completely covers and presses down on the center of the positioning seat 7, ensuring the flatness of the workpiece 100 when the airflow in the third channel is cut off. If the third outlet 8 is located at the edge of the positioning seat 7, misjudgment may easily occur, such as when the workpiece 100 tilts and covers the third outlet 8.

[0061] Furthermore, by creating a groove 10 on the positioning seat 7, the contact area between the positioning seat 7 and the workpiece 100 can be further reduced, thereby reducing the possibility of foreign objects remaining between the workpiece 100 and the positioning seat 7 after the workpiece 100 is positioned. Also, when cleaning the positioning seat 7, foreign objects on the positioning seat 7 can be cleaned into the groove 10, thus preventing contact between foreign objects and the workpiece 100.

[0062] Furthermore, by setting openings at both ends of the groove 10, foreign objects located in the groove 10 can be discharged outward through the openings, avoiding the retention of foreign objects in the groove 10 and greatly ensuring the stable fit between the workpiece 100 and the positioning seat 7.

[0063] Furthermore, when the first airflow exits from the third outlet 8, the airflow is pressed down by the workpiece 100 and diffuses outwards along the top surface 9 of the positioning seat 7, effectively cleaning the mating gap between the workpiece 100 and the positioning seat 7, and expelling any dust, chips, or other foreign objects that may be present. This not only improves the cleaning effect but also enhances the stability of the workpiece 100's placement through the uniform distribution of airflow, preventing positioning deviations caused by interference from foreign objects.

[0064] like Figures 1-6 As shown, in some embodiments, the pneumatic grippers 4 are further provided with negative pressure adsorption components. These components are connected to the second channel and are used to provide negative pressure to the second outlet 5 to limit and fix the workpiece 100 between the pneumatic grippers 4. With the assistance of negative pressure adsorption, the workpiece 100 can be stably fixed even when the clamping force is reduced. Especially during precision machining, the clamping force can be appropriately reduced to decrease the risk of workpiece 100 deformation. Simultaneously, the negative pressure adsorption supplements the fixing force, achieving near-stress-free clamping, ensuring machining accuracy, and enabling the positioning fixture to meet the fixing requirements of different machining stages.

[0065] In summary, the positioning fixture provided in this embodiment determines whether the workpiece 100 is properly positioned by monitoring the sealing of the first airflow within the positioning seat 7. When the workpiece 100 is clamped and fixed, the tightness of the clamping is determined by monitoring the air leakage in the contact area between the clamping end face 6 and the workpiece 100. The controller then dynamically adjusts the pneumatic proportional valve to achieve adaptive control of the clamping force, effectively preventing workpiece 100 deformation while ensuring its fixation. This solves the problem that traditional fixtures, when applying a constant force, easily cause micro-deformation in compressor bearings of different models, affecting the machining accuracy of the compressor bearing's inner bore.

[0066] like Figures 1-7 As shown, this embodiment also provides a boring machine tool, which includes the above-mentioned positioning fixture. By integrating the positioning fixture, the boring machine tool can achieve high-precision automatic positioning and adaptive clamping of the workpiece 100, significantly improving the positional accuracy and consistency of boring processing, and is particularly suitable for high-precision hole system processing scenarios.

[0067] In some embodiments, the boring machine tool further includes a loading mechanism and a rotary feeding mechanism. The rotary feeding mechanism includes a movable table 11, at least one set of transfer clamps 12, a rotation drive assembly, and a lifting drive assembly 14. At least one set of transfer clamps 12 is disposed on the movable table 11. Each transfer clamp 12 includes two spaced-apart transfer jaws 13, which correspond to the loading position of the loading mechanism and the worktable 1, respectively, for transferring the workpiece 100 between the loading position and the worktable 1. The rotation drive assembly drives the rotation of the movable table 11; the lifting drive assembly 14 drives the lifting of the movable table 11.

[0068] By using the dual-station setup of the transfer fixture 12, the loading and unloading operations of the workpiece 100 can be performed simultaneously, enabling the rapid transfer of the workpiece 100 between the processing station and the loading station, thereby improving production efficiency.

[0069] The rotary drive assembly is used to drive the rotation of the movable platform 11, and the lifting drive assembly 14 is used to drive the lifting of the movable platform 11. The rotary drive assembly includes, for example, a motor or a rotary cylinder, while the lifting drive assembly 14 includes cylinders, hydraulic cylinders, motors, and lead screw drives.

[0070] In addition, the rotation drive assembly can be set at the lifting end of the lifting drive assembly 14, and then the movable platform 11 can be set on the rotation end of the rotation drive assembly; or the lifting drive assembly 14 can be set at the rotation end of the rotation drive assembly, and then the movable platform 11 can be set on the lifting end of the lifting drive assembly 14.

[0071] The workpiece 100 is transferred between the loading position and the processing position by rotating the movable table 11. The lifting of the movable table 11 ensures the stable clamping and movement of the transfer gripper 13, avoiding interference with other components during the operation of the rotating feeding mechanism.

[0072] Specifically, after workpiece 100 is loaded to the loading position and the workpiece 100 on the positioning fixture is processed, the rotary feeding mechanism operates as follows. For ease of description, workpiece 100 on the loading position is referred to as the first workpiece, and workpiece 100 on the positioning fixture is referred to as the second workpiece; the two transfer grippers 13 are the first gripper and the second gripper, respectively. The rotary drive assembly drives the movable table 11 to rotate until the first gripper pair is located at the first workpiece and the second gripper pair is located at the second workpiece. Then, the lifting drive assembly 14 drives the movable table 11 to descend, causing the two transfer grippers 13 to descend synchronously. Afterward, the first gripper clamps the first workpiece, and the second gripper clamps the second workpiece. After clamping is completed, the lifting drive assembly 14 drives the movable table 11 to rise to avoid other structures, and the rotary drive assembly drives the movable table 11 to rotate, thereby realizing the transfer of workpiece 100.

[0073] To facilitate operation and subsequent processes, the movable table 11 in this embodiment rotates 180 degrees in one rotation, meaning that the loading position and the processing position are on the same straight line.

[0074] In addition, to improve work efficiency, the material transfer fixture 12 can be provided in two sets, and correspondingly, the feeding mechanism and the positioning fixture are also provided in two sets.

[0075] like Figures 1-8 As shown, this embodiment also provides a positioning method applied to the positioning fixture described above, the method comprising:

[0076] S100: Continuously introduce the first airflow into the first channel, place the workpiece 100 on the workbench 1, close the first outlet of each of the first channels, and determine the placement state of the workpiece 100 based on the flow of the first airflow.

[0077] S200: After the workpiece 100 is stably attached to the worktable 1, control each of the pneumatic grippers 4 to move synchronously to clamp the workpiece 100.

[0078] S300: Detect the leakage of the second outlet 5, adjust the opening of the pneumatic proportional valve according to the leakage, and adjust the clamping force of the pneumatic gripper 4 to control the leakage within the threshold range.

[0079] By continuously supplying the first airflow and monitoring its flow changes, real-time feedback can be provided on whether workpiece 100 completely covers all first outlets, thereby determining whether workpiece 100 is properly positioned. By synchronously moving all pneumatic grippers 4, a uniform clamping force is applied circumferentially, preventing workpiece 100 deflection or stress concentration due to asynchronous clamping. During workpiece 100 clamping, the leakage rate of the second outlet 5 is monitored simultaneously, and the clamping force is adjusted accordingly to ensure that the clamping force is sufficient to prevent workpiece 100 displacement without being excessive and causing deformation.

[0080] The threshold range can be adaptively adjusted according to different models of workpieces 100. The upper and lower limits of the threshold range must ensure sufficient clamping force to guarantee the clamping effect of workpieces 100, while avoiding over-clamping that could cause deformation of the parts.

[0081] In some embodiments, placing the workpiece 100 on the worktable 1 includes:

[0082] The workpiece 100 is placed on a plurality of positioning seats 7 arranged at intervals on the workbench 1. During the placement of the workpiece 100, the first airflow is blown out through the third outlet 8 on the positioning seat 7, pressed down by the workpiece 100 and guided to the fitting gap between the workpiece 100 and the positioning seat 7, blowing out foreign objects in the fitting gap.

[0083] During the placement of workpiece 100, the first airflow actively cleans the two opposing surfaces of the positioning seat 7 and workpiece 100, effectively removing dust, debris and other foreign objects, preventing them from affecting the positioning accuracy of workpiece 100 or damaging the surface of workpiece 100.

[0084] In some embodiments, while detecting the leakage of the second outlet 5, adjusting the opening of the pneumatic proportional valve and the clamping force of the pneumatic gripper 4 according to the leakage to control the leakage within a threshold range, the method further includes:

[0085] The physical parameters of the second channel are monitored, and a dynamic parameter curve is generated that varies over time. The physical parameters include air pressure or airflow rate.

[0086] The dynamic parameter curve is compared with multiple standard feature curves, each of which corresponds to a workpiece model 100.

[0087] Based on the comparison results, the model of the workpiece 100 currently being clamped is identified.

[0088] By analyzing the dynamic parameter curves generated from the physical parameters of the second channel, the characteristic patterns of different workpiece models 100 during the clamping process can be extracted, enabling automatic identification of workpiece models 100 and facilitating error prevention and traceability operations for workpiece models 100.

[0089] Specifically, by continuously monitoring the physical parameters of the second channel, the changes in airflow characteristics of workpiece 100 during clamping can be obtained. Different types of bearings exhibit unique airflow dynamics during clamping due to differences in their structural dimensions, weight, and materials, thus enabling model identification.

[0090] Furthermore, the comparison of the dynamic parameter curve with multiple standard feature curves is achieved by extracting at least one feature value from the dynamic parameter curve and matching that feature value with a pre-stored feature value in the standard feature curve.

[0091] By employing feature extraction and matching methods, the complexity of data processing can be effectively reduced, recognition efficiency can be improved, and the risk of misjudgment caused by small fluctuations in the curve can be reduced.

[0092] Furthermore, the feature value includes any one or a combination of the following:

[0093] The amplitude, width, or area of ​​the pulses or plateaus appearing in the dynamic parameter curve;

[0094] The time from the start of the dynamic parameter curve to the attainment of a stable sealing state;

[0095] The descending or ascending slope of the dynamic parameter curve;

[0096] The number of fluctuations in the dynamic parameter curve before reaching a stable sealing state.

[0097] Different bearing models exhibit unique pulsation characteristics at the moment of contact due to variations in their outer diameter, wall thickness, and weight. For example, larger bearings, due to their greater weight, produce a more pronounced pressure pulsation at the moment of contact, thus providing a primary basis for distinguishing their models.

[0098] The time it takes for the dynamic parameter curve to reach a stable sealing state from the start of its change can reflect the fit characteristics between the bearing and the clamping end face 6. Different types of bearings will exhibit different stabilization time characteristics due to differences in their structural rigidity and sealing surface size. For example, thin-walled bearings require a longer stabilization time, while thick-walled bearings can reach a stable state quickly.

[0099] The slope characteristic reflects the rate of change of airflow parameters during bearing clamping. Different bearing models, due to differences in contact area and sealing surface roughness, will cause the airflow parameters to stabilize at different rates. For example, precision bearings, due to their higher surface finish, will exhibit a steeper downward slope of the curve.

[0100] The number of fluctuations in the dynamic parameter curve before reaching a stable sealing state reflects the minute adjustments made by the bearing during the positioning process. For example, bearings with seals will experience multiple small fluctuations on the curve due to the elastic deformation of the rubber components.

[0101] In some embodiments, it also includes:

[0102] Before the workpiece 100 is precision machined, the clamping force of the pneumatic gripper 4 is reduced and the second outlet 5 generates negative pressure, thereby generating negative pressure adsorption force between the clamping end face 6 and the workpiece 100.

[0103] While maintaining a negative pressure at the second outlet 5, the workpiece 100 is precision machined.

[0104] By reducing the clamping force and supplementing it with negative pressure adsorption, the risk of workpiece 100 deformation can be minimized during the finishing stage while maintaining sufficient fixing force. During the finishing process, by reducing the clamping force to an extremely low level and providing negative pressure through the second outlet 5 to assist in adsorbing the workpiece 100, near-stress-free clamping can be achieved, maximizing the protection of machining accuracy and surface quality.

[0105] Furthermore, the clamping force applied by the pneumatic gripper 4 is reduced to zero, so that the workpiece 100 is fixed only by the negative pressure adsorption force. Reducing the clamping force to zero completely eliminates the stress effects caused by mechanical contact. At this time, the workpiece 100 is in a negative pressure adsorption state, which not only meets the fixing requirements of precision machining, but also effectively prevents deformation of the workpiece 100 during processing due to the uniformity of the negative pressure distribution.

[0106] In summary, the positioning method provided in this embodiment detects the placement position of the workpiece 100 by monitoring the on / off state of the first airflow, monitors the leakage of the second airflow at the clamping end face 6, and dynamically adjusts the clamping force of the pneumatic gripper 4, thus achieving adaptive control of the clamping force. Automatic identification of the workpiece 100 model is achieved by analyzing the dynamic curve of the airflow parameters. During the finishing stage, by significantly reducing the mechanical clamping force and supplementing it with negative pressure adsorption, near-stress-free flexible fixation is achieved, thereby maximizing machining accuracy.

[0107] In the description of this application, workpiece 100 is used as an example of a bearing for illustrative purposes only. This is merely to illustrate the technical principles and advantages of this application and is not intended to limit the scope of this application. Those skilled in the art should understand that the positioning fixture and method described in this application are also applicable to other workpieces that require precise positioning and clamping, such as discs, sleeves, plates, etc., for example, gear blanks, flanges, end covers, sealing rings, etc.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A positioning fixture, characterized in that, include: A workbench (1) is provided with a fixture hole (2). The workbench (1) is also provided with a plurality of first channels. A first airflow flows through the first channel. A first detection element is also provided in the first channel to detect the flow of the first airflow. The first outlet of each first channel is evenly opened on the workbench (1) along the circumference of the fixture hole (2). The workbench (1) is used to place workpieces (100) and to close each first outlet through the workpieces (100). Multiple clamping mechanisms (3) are evenly spaced along the circumference of the clamping hole (2). Each clamping mechanism (3) includes a pneumatic gripper (4), a pneumatic proportional valve, a leak detection element, and a controller. Each pneumatic gripper (4) moves reciprocally along the radial direction of the clamping hole (2). A second channel is provided inside the pneumatic gripper (4), and a second airflow flows through the second channel. The second outlet (5) of the second channel is opened on the clamping end face (6) of the pneumatic gripper (4). The clamping end face (6) is used to contact the workpiece (100) so as to close the second outlet (5) through the workpiece (100). The air leakage detection device is used to detect the amount of air leakage at the second outlet (5). The controller adjusts the opening of the pneumatic proportional valve according to the amount of air leakage to adjust the clamping force of the pneumatic gripper (4). After the air leakage detection device detects the trend of the amount of air leakage at the second outlet (5) decreasing first and then increasing, the controller reduces the opening of the pneumatic proportional valve to reduce the clamping force.

2. The positioning fixture according to claim 1, characterized in that, The workbench (1) is also provided with a plurality of positioning seats (7) evenly spaced along the circumference of the fixture hole (2). Each positioning seat (7) has a third channel. The third entrance of each third channel is connected to each first exit. The third exit (8) of each third channel is opened on the top surface (9) of each positioning seat (7). The workpiece (100) is placed on the top surface (9) to close the third exit (8).

3. The positioning fixture according to claim 2, characterized in that, The third outlet (8) is located in the middle of the top surface (9). At least one groove (10) is provided on the top surface (9). The groove (10) is located on the top surface (9) along the height direction of the positioning seat (7). The two ends of the groove (10) are open along the extension direction of the groove (10).

4. The positioning fixture according to claim 1, characterized in that, The pneumatic gripper (4) is also provided with a negative pressure adsorption component, which is connected to the second channel and is used to provide negative pressure to the second outlet (5) to limit and fix the workpiece (100) between each of the pneumatic grippers (4).

5. A boring machine tool, characterized in that, Including the positioning fixture as described in any one of claims 1-4.

6. The boring machine tool according to claim 5, characterized in that, It also includes a feeding mechanism and a rotary feeding mechanism, wherein the rotary feeding mechanism includes: Activity table (11); At least one set of transfer clamps (12) is provided on the movable table (11). The transfer clamps (12) include two spaced transfer jaws (13). The two transfer jaws (13) correspond to the loading position of the loading mechanism and the worktable (1) respectively, and are used to transfer the workpiece (100) between the loading position and the worktable (1). A rotation drive assembly is used to drive the rotation of the movable platform (11); A lifting drive assembly (14) is used to drive the lifting of the movable platform (11).

7. A positioning method, characterized in that, Applied to the positioning fixture as described in any one of claims 1-4, the method comprises: A first airflow is continuously introduced into the first channel, and the workpiece (100) is placed on the workbench (1). The first outlet of each of the first channels is closed, and the placement state of the workpiece (100) is determined according to the flow of the first airflow. After the workpiece (100) is stably attached to the worktable (1), each of the pneumatic grippers (4) is controlled to move synchronously to clamp the workpiece (100). The leakage of the second outlet (5) is detected, and the opening of the pneumatic proportional valve is adjusted according to the leakage, and the clamping force of the pneumatic gripper (4) is adjusted to control the leakage within the threshold range.

8. The positioning method according to claim 7, characterized in that, The step of placing the workpiece (100) on the worktable (1) includes: The workpiece (100) is placed on a plurality of positioning seats (7) arranged at intervals. During the placement of the workpiece (100), the first airflow is blown out through the third outlet (8) on the positioning seat (7), pressed down by the workpiece (100) and guided to the fitting gap between the workpiece (100) and the positioning seat (7), blowing out foreign objects in the fitting gap.

9. The positioning method according to claim 7, characterized in that, The process of detecting the leakage at the second outlet (5), adjusting the opening of the pneumatic proportional valve based on the leakage amount, and adjusting the clamping force of the pneumatic gripper (4) to control the leakage amount within a threshold range, also includes: The physical parameters of the second channel are monitored, and a dynamic parameter curve is generated that varies over time. The physical parameters include air pressure or airflow rate. The dynamic parameter curve is compared with multiple standard feature curves, and each standard feature curve corresponds to a workpiece (100) model. Based on the comparison results, the model of the workpiece (100) currently being clamped is identified.

10. The positioning method according to claim 7, characterized in that, Also includes: Before the workpiece (100) is finished, the clamping force of the pneumatic gripper (4) is reduced and the second outlet (5) generates a negative pressure, thereby generating a negative pressure adsorption force between the clamping end face (6) and the workpiece (100). While the second outlet (5) is under negative pressure, the workpiece (100) is precision machined.

Images