Integrated force and displacement real-time measurement device and method for shaft-hole flexible assembly

Abstract

The invention belongs to the technical field of micro part assembly, and discloses an integrated force and displacement real-time measurement device and method for shaft-hole flexible assembly. The device comprises a displacement measurement unit, a compliance unit, a force measurement unit and a force calibration unit. The displacement measuring unit is used for measuring the deflection displacement of the part during assembly; the flexible unit is used for providing various flexibility in the hole and shaft assembling process; the force measuring unit is mainly used for measuring force data in all directions in the hole and shaft assembling process. And the force calibration unit is used for calibrating the force sensor. Through cooperation of the modules, real-time measurement of force position data in the flexible assembling process of the hole shaft part is achieved. Through cooperation of the assembly body and the assembly operation module, automatic flexible assembly and force position data measurement and analysis of the hole and shaft parts are achieved, the assembly efficiency and the assembly precision are effectively improved, and related experimental design is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of tiny parts assembly, and in particular to a device and method for real-time measurement of integrated force and displacement for shaft-hole compliant assembly. Background Art

[0002] Precision assembly technology plays a vital role in modern manufacturing. Especially in high-tech fields such as aerospace, biomedicine, semiconductor integrated circuits, etc., the application of precision assembly is particularly important because these fields have extremely high requirements for the performance and reliability of equipment. With the gradual miniaturization and integration of devices, the difficulty of precision assembly is also increasing, requiring higher precision requirements for the size, material, and structure of parts, and at the same time, the efficiency and degree of automation of assembly also need to be continuously improved.

[0003] As a common form of precision assembly, hole-shaft assembly has significant significance. In the process of hole-shaft assembly, the matching accuracy of the shaft and the hole directly affects the transmission efficiency, stability and life of the entire mechanical system. High-precision hole-shaft assembly can effectively reduce the friction and vibration between mechanical parts, ensure the smooth operation of the system, and extend the service life of the equipment. In modern manufacturing, hole-shaft assembly is not only to achieve a simple connection, but also to ensure the overall performance and reliability of the mechanical system.

[0004] In the hole-shaft assembly, through the real-time measurement of force data and displacement data, various parameters in the assembly process can be accurately controlled to ensure that each assembly step meets the design requirements. These measurements not only help engineers understand the actual status of each component during the assembly process, but also optimize the design and improve assembly accuracy and efficiency. Force data such as load and pressure and displacement data such as shaft displacement and offset can effectively monitor and adjust assembly quality, prevent potential assembly problems, and ensure stable performance of the final product. Summary of the invention

[0005] The purpose of the present invention is to overcome the difficulties in the current assembly process of small gap hole shaft parts and the unreliable measurement of assembly force data, and provide a device and method for real-time measurement of integrated force and displacement for shaft-hole compliant assembly, which is applied to the field of assembly of small parts. By real-time measurement of axial force, X, Y, Z forces and displacement in three directions of X, Y, and Z during the assembly process, combined with force calibration, the flexibility and automatic adjustment function of the shaft-hole assembly process are ensured, and the assembly accuracy and efficiency are improved.

[0006] The technical solution of the present invention is as follows: a device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly, comprising a displacement measurement unit 22, a force measurement unit 24, a force calibration unit 25 and a compliance unit 23;

[0007] The displacement measuring unit 22 includes a plurality of inductive micrometers 1;

[0008] The compliance unit 23 is located between the displacement measuring unit 22 and the force measuring unit 24;

[0009] The force calibration unit 25 includes three evenly distributed axial force sensors 10 and a three-dimensional force sensor 12; the two ends of the axial force sensor 10 are respectively fixed to the upper platform 3 of the axial force sensor and the lower platform 11 of the axial force sensor;

[0010] The inductive micrometer 1 is fixed on the upper platform 3 of the axial force sensor. In the initial state, the circular probe is kept at a certain distance from the lower platform 11 of the axial force sensor. When working, the circular probe pops up with the measuring rod and rests on the upper platform 11 below the axial force sensor to measure the expansion and contraction amount of the circular probe, which is used to calculate the deflection displacement when the shaft parts are assembled.

[0011] The axial force sensor 10 is installed above the platform 11 below the axial force sensor; the three-dimensional force sensor 12 is installed below the platform 11 below the axial force sensor; the axial force sensor 10 measures the Z-direction force generated during real-time detection of assembly; the three-dimensional force sensor 12 is used to detect the X, Y, and Z-direction forces generated during assembly in real time;

[0012] The matching groove at the top of the axial force sensor 10 matches with the ball head of the plunger 5 installed below the platform 3 above the axial force sensor, a part of the front end of the ball head of the plunger 5 is stuck in the matching groove, and the plunger 5 has a certain initial compression in the initial state, so as to ensure that the plunger 5 only generates axial displacement but not radial displacement in the hanging state;

[0013] The force calibration unit 25 is installed on the hole part mounting plate 26, and includes a linear bearing a13, a guide shaft 14, a spring 15, a linear bearing b17, and a calibration force sensor 18; the two ends of the guide shaft 14 are respectively connected to the linear bearing a13 and the linear bearing b17, and the guide shaft 14 is sleeved with a spring 15. During calibration, the spring 15 is compressed to assist the calibration force sensor 18 to achieve the calibration purpose; the calibration force sensor 18 is connected to the linear bearing a13; the linear bearing a13 slides on the guide shaft 14 to compress the spring 15, and the data of the calibration force sensor 18 is adjusted by the elastic force generated by the compression of the spring 15; the calibration force sensor 18 is located on one side of the shaft part 28 and contacts with it, and the axial force sensor 10 and the three-dimensional force sensor 12 are calibrated by contacting the shaft part 28.

[0014] Furthermore, the compliance unit 23 includes a plurality of plungers 5, a spherical bearing fixing seat assembly 8, and a support shaft 9; the plunger 5 is compliant in the Z direction by compressing the spherical plunger head when working; the support shaft 9 is a stepped type, one end of which is inserted into the ball joint 7 in the spherical bearing fixing seat assembly 8 and locked, while ensuring that the support shaft 9 has a certain rotation angle; the ball joint 7 ensures that the shaft parts have X and Y rotational freedom when working; the support shaft 9 is connected to the platform 11 below the axial force sensor.

[0015] A method for real-time measurement of integrated force and displacement for shaft-hole compliant assembly includes the following steps;

[0016] The first step is to adjust the XY slide 29 placed under the hole part mounting plate 26 and the Z slide 21 placed behind the device mounting plate 27, so that the force calibration unit 25 contacts the measured shaft part 28 installed under the three-dimensional force sensor 12. After the two contact, start the calibration force sensor 18, the axial force sensor 10, and the three-dimensional force sensor 12; continue to adjust the XY slide 29 so that the hole part mounting plate 26 drives the entire force calibration unit 25 to move in the XY direction and contact the shaft part 28 that remains stationary, thereby compressing the spring 15, and calculate and summarize the real-time data and changes of the calibration force sensor 18, the axial force sensor 10, and the three-dimensional force sensor 12; complete the calibration of the axial force sensor 10 and the three-dimensional force sensor 12 according to the difference and change law of the data;

[0017] In the second step, after the calibration is completed, the force calibration unit 25 is removed; the XY slide 29 and the Z slide 21 are adjusted, and the data changes of the axial force sensor 10 and the three-dimensional force sensor 12 are used to check whether the shaft part 28 and the hole part have initial contact; after the initial contact, the Z slide 21 is adjusted to press the shaft part 28 down to assemble the hole and shaft; during the assembly process, the compliance unit 23 automatically adjusts the hole and shaft posture;

[0018] The third step is to turn on the axial force sensor 10 and the three-dimensional force sensor 12 in the force measurement unit 24 in real time during the assembly process for detection; the three-dimensional force sensor 12 directly detects the X, Y, and Z component force data; the three evenly distributed axial force sensors 10 detect the Z direction data separately; the axial force sensor 10 is connected to the ball head of the plunger 5, and the plunger 5 is compressed during the assembly process to detect the force data in real time;

[0019] The fourth step is to turn on the inductive micrometer 1 in the displacement measuring unit 22 for detection in real time during the assembly process; during operation, due to the movement of the compliance unit 23, the circular probe of the inductive micrometer 1 performs telescopic movement, and the telescopic amount of the circular probe of the inductive micrometer 1 is detected in real time and the deflection displacement of the part is calculated through it. The deflection displacement generated by the shaft part during the assembly process is obtained through the displacement data.

[0020] The beneficial effects of the present invention are as follows: the calibration of the axial force sensor and the three-dimensional force sensor is realized through the force calibration unit, the automatic assembly of the hole shaft is realized through the compliance unit, the real-time detection of the force information in the assembly is realized through the force measurement unit, and the real-time detection of the deflection and displacement of the parts in the assembly is realized through the displacement measurement unit. The above units increase the compliance in the assembly process and reduce the incidence of jamming in the assembly process; the real-time detection system has a more timely and comprehensive detection function for the assembly process, effectively reducing the damage of the parts caused by excessive force and other problems, and ensuring the precision and stability of the hole shaft assembly process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a displacement measurement unit;

[0022] Figure 2 It is the front view of the compliant unit;

[0023] Figure 3 It is the top view of the compliant unit;

[0024] Figure 4 It is a schematic diagram of the force measurement unit;

[0025] Figure 5 It is a schematic diagram of the force calibration unit;

[0026] Figure 6 Schematic diagram of the device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly.

[0027] In the figure: 1-inductive micrometer, 2-inductive micrometer holder, 3-upper platform of axial force sensor, 4-inductive micrometer clamping device, 5-plunger, 6-gasket, 7-ball joint, 8-spherical bearing fixing seat assembly, 9-support shaft, 10-axial force sensor, 11-lower platform of axial force sensor, 12-three-dimensional force sensor, 13-linear bearing a, 14-guide shaft, 15-spring, 16-linear bearing mounting plate, 17-linear bearing b, 18-calibration force sensor, 19-force sensor mounting plate, 20-calibration unit support frame; 21-Z slide, 22-displacement measurement unit, 23-compliance unit, 24-force measurement unit, 25-force calibration unit, 26-hole part mounting plate, 27-device mounting plate, 28-axis part, 29-XY slide, 30-pad, 31-workbench holder. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and implementation plans.

[0029] A device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly includes a displacement measurement unit 22, a compliance unit 23, a force measurement unit 24, and a force calibration unit 25.

[0030] The displacement measurement unit 22 is mainly used to measure the deflection displacement of parts during assembly, including three inductive micrometers 1, three inductive micrometer holders 2, upper platforms 3 of axial force sensors, and three inductive micrometer clamping devices 4; the inductive micrometer 1 measures the expansion and contraction of three circular probes evenly distributed in real time during operation to calculate the deflection displacement of parts during assembly; the inductive micrometer holder 2 is installed at the upper limit groove of the upper platform 3 of the axial force sensor, and the inductive micrometer clamping device 4 is installed on the inductive micrometer holder 2, and the position of the inductive micrometer 1 is fixed by the locking hole; the upper platform 3 of the axial force sensor is used to install the inductive micrometer holder 2, and connect the lower components at the same time. The deflection displacement generated during the hole-shaft assembly is detected by the expansion and contraction of the inductive micrometer 1, which is used to measure the displacement change of the shaft parts during the assembly process. Through the displacement data, the deflection displacement generated by the shaft parts during the assembly process can be intuitively understood, and the data can be used for solving the measured force data.

[0031] The compliance unit 23 is mainly used to provide various compliances during the hole-shaft assembly process, including three plungers 5, gaskets 6, ball joints 7, spherical bearing fixing seat components 8, and support shafts 9; the plunger 5 is compliant in the Z direction by compressing the spherical plunger head during operation; the gasket 6 is placed above the spherical bearing fixing seat component 8, and is locked with the support shaft 9 inserted in the ball joint 7 through the threaded hole in the gasket 5, so as to ensure that the support shaft 9 is suspended and has a certain rotation angle; the ball joint 7 ensures that the shaft part has X and Y rotational freedom during operation; the support shaft 9 is used to lock the spherical bearing fixing seat component 8, and is connected to the platform 11 below the axial force sensor through it. The spherical bearing fixing seat component 8 provides passive rotational compliance of the part in the X and Y directions, and the plunger 5 provides passive linear compliance of the part in the Z direction.

[0032] The force measuring unit 24 is mainly used to measure the X, Y, and Z force data during the hole-shaft assembly process, and includes three axial force sensors 10, a platform 11 below the axial force sensor, and a three-dimensional force sensor 12; the axial force sensor 10 is used to measure the Z force generated during assembly, and detect the Z force generated during assembly in real time. At the same time, it has a hole groove on the top, which is used to cooperate with the ball head of the plunger 5 to ensure that the plunger 5 only produces axial displacement but not radial displacement when suspended; the platform 11 below the axial force sensor is used to install the force sensor, the axial force sensor 10 is installed above it, and the three-dimensional force sensor 12 is installed below it; the three-dimensional force sensor 12 is used to measure the X, Y, and Z forces generated during assembly, and detect the X, Y, and Z forces generated during assembly in real time.

[0033] The force calibration unit 25 is mainly used to calibrate the axial force sensor 10 and the three-dimensional force sensor 12, and includes a linear bearing a 13, a guide shaft 14, a spring 15, a linear bearing mounting plate 16, a linear bearing b 17. Calibration force sensor 18, force sensor mounting plate 19, calibration unit support frame 20; the spring 15 on the guide shaft 14 is compressed by sliding the linear bearing a13 on the guide shaft 14, and the data of the calibration force sensor 18 is adjusted by the elastic force generated by the compression of the spring 15; the calibration force sensor 18 is installed on the force sensor mounting plate 19, which is regarded as a standard force sensor to calibrate the axial force sensor 10 and the three-dimensional force sensor 12, so that the force data detected by the two in real time during assembly is more accurate; the linear bearing b17 is installed on the linear bearing mounting plate 16, and is located at both ends of the guide shaft 14 respectively with the linear bearing a13, and the above-mentioned components are connected to the calibration unit support frame 20 through the linear bearing mounting plate 16; the calibration module support frame 20 is installed above the hole part mounting plate 26, and supports the entire force calibration unit 25.

[0034] Taking a hole-shaft assembly process based on automated assembly application as an example, the specific implementation steps of the present invention are described in combination with the technical solution and the accompanying drawings.

[0035] In the first step, the force calibration unit 25 is brought into contact with the measured shaft part 28 by adjusting the XY slide 29 and the Z slide 21. After the two are in contact, the calibration force sensor 18, the axial force sensor 10, and the three-dimensional force sensor 12 are turned on, and then the XY slide 29 is adjusted to make the linear bearing a13 compress the spring 15 on the guide shaft 14. At this time, the real-time detection data and changes of the calibration force sensor 18, the axial force sensor 10, and the three-dimensional force sensor 12 are observed, and the calibration of the axial force sensor 10 and the three-dimensional force sensor 12 is completed according to the difference and the change law.

[0036] The second step is to remove the force calibration unit 25 after the calibration work is completed, adjust the movement of the XY slide 29 and the Z slide 21, and determine whether the shaft part 28 and the hole part have initial contact based on the axial force sensor 10 and the three-dimensional force sensor 12; after the initial contact occurs, adjust the Z slide 21 to press the shaft part 28 down to perform the hole-shaft assembly work; if jamming occurs due to the deviation of the hole-shaft posture during assembly, the assembly force will cause the ball joint 7 and the support shaft 9 in the compliance unit 23 to rotate, and the plunger 5 will move linearly in the Z direction, thereby automatically adjusting the hole-shaft posture to achieve the purpose of automatic passive compliance, and allowing the assembly to continue until the assembly is successfully completed.

[0037] In the third step, when the second step of assembly is in progress, the axial force sensor 10, the three-dimensional force sensor 12 and its supporting program in the force measurement unit 24 must be opened synchronously for real-time detection; when working, the three-dimensional force sensor 12 directly contacts the shaft part 28, and can detect the three components of X, Y, and Z more intuitively; but since there is a certain coupling relationship between the three forces of the three-dimensional force sensor 12, and the Z-direction force has the largest change amplitude during assembly and is also the component that needs the most attention, three evenly distributed axial force sensors 10 are used for separate detection, and the X and Y-direction force data of the three-dimensional force sensor are mainly used, and the Z-direction force data is used to verify the axial force sensor; the axial force sensor 10 is installed above the platform 11 below the axial force sensor, and there is a screw hole on the top connected to the ball head of the plunger 5. When the hole and shaft are assembled, the plunger is compressed and the force is detected in real time; the force measurement unit 24 achieves the purpose of using a computer program to detect the assembly force in real time through the axial force sensor 10 and the three-dimensional force sensor 12, and the hole and shaft assembly state can be monitored in real time through the measured force data to prevent problems such as jamming and part damage caused by excessive force.

[0038] The fourth step is that when the second step of assembly work is carried out, the inductive micrometer 1 and its related programs in the displacement measurement unit 22 must be opened synchronously to perform real-time detection work; the three inductive micrometers 1 are locked by the inductive micrometer clamping device 4, and are installed on the upper platform 3 of the axial force sensor according to three evenly distributed inductive micrometer holders 2, and the three circular probes of the inductive micrometer 1 are against the lower platform 11 of the axial force sensor and have a certain initial compression amount; during assembly, the ball joint 7 in the compliance unit 23 rotates to drive the support shaft 9 to rotate in the X, Y, and Z directions, and the plunger 5 moves linearly in the Z direction, causing the lower platform 11 of the axial force sensor directly connected to the support shaft 9 to rotate in the X, Y, and Z directions. At this time, the circular probe of the inductive micrometer 1 will perform telescopic movement, and its telescopic amount will be detected in real time through the related program and the deflection displacement of the parts will be solved. Through the displacement data, the deflection displacement of the shaft parts during the assembly process can be intuitively understood, and the data can be used for the solution of the measured force data.

Claims

1. A device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly, characterized in that: The device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly comprises a displacement measurement unit (22), a force measurement unit (24), a force calibration unit (25) and a compliant unit (23); The displacement measuring unit (22) comprises a plurality of inductive micrometers (1); The compliance unit (23) is located between the displacement measurement unit (22) and the force measurement unit (24); The force calibration unit (25) comprises three evenly distributed axial force sensors (10) and a three-dimensional force sensor (12); two ends of the axial force sensor (10) are respectively fixed to an upper platform (3) of the axial force sensor and a lower platform (11) of the axial force sensor; The inductive micrometer (1) is fixed on the upper platform (3) of the axial force sensor. In the initial state, the circular probe of the inductive micrometer keeps a distance from the lower platform (11) of the axial force sensor. When working, the circular probe pops out with the measuring rod and abuts against the upper platform (11) below the axial force sensor to measure the expansion and contraction amount of the circular probe, which is used to calculate the deflection displacement amount when the shaft parts are assembled. The axial force sensor (10) is installed above the platform (11) below the axial force sensor; the three-dimensional force sensor (12) is installed below the platform (11) below the axial force sensor; the axial force sensor (10) measures the Z-direction force generated during assembly in real time; the three-dimensional force sensor (12) is used to detect the X-direction force, Y-direction force, and Z-direction force generated during assembly in real time; The matching groove at the top of the axial force sensor (10) matches with the ball head of the plunger (5) installed below the platform (3) above the axial force sensor, a part of the front end of the ball head of the plunger (5) is stuck in the matching groove, and the plunger (5) has a certain initial compression amount in the initial state, so as to ensure that the plunger (5) only generates axial displacement but not radial displacement in the suspended state; The force calibration unit (25) is installed on the hole part mounting plate (26), and comprises a linear bearing a (13), a guide shaft (14), a spring (15), a linear bearing b (17), and a calibration force sensor (18); the two ends of the guide shaft (14) are respectively connected to the linear bearing a (13) and the linear bearing b (17); the guide shaft (14) is sleeved with a spring (15); during calibration, the spring (15) is compressed to assist the calibration force sensor (18) to achieve the calibration purpose; the calibration force sensor (18) is connected to the linear bearing a (13); the linear bearing a (13) slides on the guide shaft (14) to compress the spring (15), and the data of the calibration force sensor (18) is adjusted by the elastic force generated by the compression of the spring (15); the calibration force sensor (18) is located on one side of the shaft part (28) and contacts with it, and performs calibration work on the axial force sensor (10) and the three-dimensional force sensor (12) by contacting with the shaft part (28).

2. The device for real-time measurement of integrated force and displacement for shaft-hole compliant assembly according to claim 1, characterized in that: The compliance unit (23) comprises a plurality of plungers (5), a spherical bearing fixing seat assembly (8), and a support shaft (9); the plunger (5) is compliant in the Z direction by compressing the spherical plunger head when working; the support shaft (9) is of a stepped type, one end of which is inserted into the ball joint (7) in the spherical bearing fixing seat assembly (8) and locked, while ensuring that the support shaft (9) has a certain rotation angle; the ball joint (7) ensures that the shaft part has rotational freedom in the X and Y directions when working; the support shaft (9) is connected to the platform (11) below the axial force sensor.

3. A method for real-time measurement of integrated force and displacement for shaft-hole compliant assembly, characterized in that: The steps include: The first step is to adjust the XY slide (29) placed under the hole part mounting plate (26) and the Z slide (21) placed behind the device mounting plate (27) so that the force calibration unit (25) contacts the measured shaft part (28) installed under the three-dimensional force sensor (12). After the two contact, the calibration force sensor (18), the axial force sensor (10), and the three-dimensional force sensor (12) are started; the XY slide (29) is continued to be adjusted so that the hole part mounting plate (26) drives the entire force calibration unit (25) to move in the XY direction and contact the shaft part (28) that remains stationary, thereby compressing the spring (15), and calculating and summarizing the real-time data and changes of the calibration force sensor (18), the axial force sensor (10), and the three-dimensional force sensor (12); and the calibration of the axial force sensor (10) and the three-dimensional force sensor (12) is completed according to the difference and change law of the data; In the second step, after the calibration is completed, the force calibration unit (25) is removed; the XY slide table (29) and the Z slide table (21) are adjusted, and the data changes of the axial force sensor (10) and the three-dimensional force sensor (12) are used to check whether the shaft part (28) and the hole part have initial contact; after the initial contact, the Z slide table (21) is adjusted to press the shaft part (28) downward to perform hole-shaft assembly; during the assembly process, the compliant unit (23) automatically adjusts the hole-shaft posture; The third step is to start the axial force sensor (10) and the three-dimensional force sensor (12) in the force measurement unit (24) in real time during the assembly process for detection; the three-dimensional force sensor (12) directly detects the X, Y, and Z component force data; the three evenly distributed axial force sensors (10) detect the Z direction data separately; the axial force sensor (10) is connected to the ball head of the plunger (5), and the plunger (5) is compressed during the assembly process to detect the force data in real time; The fourth step is to start the inductive micrometer (1) in the displacement measuring unit (22) in real time during the assembly process for detection; during operation, due to the movement of the compliance unit (23), the circular probe of the inductive micrometer (1) performs telescopic movement, and the telescopic amount of the circular probe of the inductive micrometer (1) is detected in real time and the deflection displacement of the part is calculated therefrom, and the deflection displacement of the shaft part generated during the assembly process is obtained through the displacement data.

Images