Active and passive compliant automatic assembly device and method for small gap shaft hole parts

Abstract

The present invention belongs to the field of precision assembly technology, and discloses an active and passive compliant automatic assembly device and method for shaft-hole parts with small gaps. The automatic assembly device for shafts with small gaps includes an active adjustment unit, a passive compliance unit for hole parts, and a passive compliance unit for shaft parts. The active adjustment unit provides power for adjusting the position of the hole parts to complete the position adjustment of the target hole parts. The passive compliance unit for hole parts realizes the passive compliance of the hole during the assembly process, realizes the longitudinal passive compliance of the hole through the internal guide shaft and linear bearing, and realizes the planar passive compliance of the hole through the planar compliance ring. The passive compliance unit for shaft parts realizes the longitudinal movement of the shaft during the assembly process and realizes the passive compliance of the posture of the shaft through the internal plunger. During assembly, active and passive mixed compliance control is used, so that only the angle between the hole and the shaft is adjusted during adjustment, and the hole and shaft position deviation is adjusted by the flexible system, which reduces the accuracy requirements, simplifies the model complexity, improves the assembly speed, and reduces the force between parts.

Description

Technical Field

[0001] The present invention relates to the technical field of precision assembly, and in particular to an active and passive compliant automatic assembly device and method for micro-gap shaft hole parts. Background Art

[0002] Shaft-and-hole assembly is an important process in the assembly field. Currently, precision shaft-and-hole assembly is mostly performed manually with the assistance of tools. The assembly quality is highly dependent on the workers' own technical level, with low efficiency and productivity, and it is difficult to ensure assembly consistency. During the precision assembly of shafts and holes with small clearances, due to the small clearance and low allowable contact force, jamming between shafts and holes, excessive contact force, and even damage to parts often occur during assembly, which will seriously affect the final assembly quality of the parts. In actual situations, the force state is more complex, and there are sensor errors, gravity compensation errors, mechanical installation errors, processing errors, etc., which require complex models and high adjustment accuracy as support. Therefore, integrating active and passive compliance control systems in precision shaft-and-hole assembly equipment directly promotes the development of high automation in the assembly of shaft-and-hole parts with small clearances. Summary of the Invention

[0003] In response to the above problems, the present invention proposes an active and passive compliant automatic assembly device and method for shaft hole parts with small gaps. By combining active and passive compliance during the assembly process, it is used to solve the jamming phenomenon that occurs during the assembly of shaft hole parts and avoid excessive contact force between shaft holes during the assembly process.

[0004] The technical solution of the present invention is as follows: an automatic assembly device for active and passive compliance of shaft and hole parts with small gaps, comprising an active adjustment unit 33, a hole part passive compliance unit 34 and a shaft part passive compliance unit 35, which are connected in sequence;

[0005] The active adjustment unit 33 provides power for adjusting the position of the hole part, and combines the force and torque information to complete the posture adjustment of the target hole part 19; the active adjustment unit 33 includes an XY motion slide 1, an XY axis motion turntable 2 and a connecting plate 3 on the turntable, which are connected in sequence;

[0006] The passive compliance unit 34 of the hole part realizes the passive compliance of the target hole part 19 during the assembly process; the passive compliance unit 34 of the hole part includes a spring 6, a linear bearing 5 and a flexible guide shaft 8; one end of the spring 6 is connected to the platform 16 below the spring, and the other end is connected to the force sensor mounting platform 15, and the spring 6 is in a compressed state; the linear bearing 5 is evenly fixed on the platform 16 below the spring; one end of the guide shaft 8 is connected to the linear bearing 5, and the other end is fixed on the force sensor mounting platform 15 through the guide shaft support 9; the force sensor mounting platform 15 slides up and down under the support of the spring 6 through the guide shaft 8 and the linear bearing 5; the axial force sensor 14 is evenly fixed on the force sensor mounting platform 15 in an annular manner; a groove is provided above the axial force sensor 14; cylindrical grooves are provided above and below the planar flexible platform 13; the plunger 11 is fixed to the groove by interference fit The groove and the cylindrical groove; the plunger 11 only transmits axial force to the axial force sensor 14; the flat flexible ring 12 is clearance-fitted in the cylindrical groove above the flat flexible platform 13; the hole part mounting plate 17 is placed above the flat flexible ring 12; there is rolling friction between the hole part mounting plate 17 and the flat flexible platform 13, which provides lateral flexibility during the shaft hole assembly process; the upper surface of the hole part mounting plate 17 is provided with a ventilation groove to connect the internal and external air pressure of the hole part; two hole clamping tools are symmetrically installed on the upper surface of the hole part mounting plate 17, and the target hole part 19 is clamped between the two hole clamping tools and installed on the hole part mounting plate 17; a flexible limit ring 21 is sleeved on the outer periphery of the hole part mounting plate 17; the flexible limit ring 21 is fixed to the fixing ring 4 through the limit ring support shaft 10 to ensure that the relative distance between the platform 16 below the spring and the hole part mounting plate 17 is constant;

[0007] The hole part passive compliance unit 34 is connected to the platform 16 below the spring through the spring 6 to achieve Z-direction compliance; the Z-direction compliance is guided by the linear bearing 5 and the guide shaft 8; the torque information is measured by the annularly distributed axial force sensor 14; the horizontal compliance in the X and Y directions and the rotational compliance in the Z direction are achieved by the planar compliance ring 12; the shaft part passive compliance unit 35 achieves the longitudinal movement and passive compliance of the target shaft part 22 during the assembly process;

[0008] The passive compliance unit 35 of the shaft part includes a three-dimensional force sensor 23, a spherical bearing 26, a connecting plate 28 on the bearing, an axial support 29, a Z-axis slide connecting plate 30, an axial adapter plate 31 and a Z-axis stepper motor 32; the Z-axis stepper motor 32 is connected to the axial adapter plate 31 through the Z-axis slide connecting plate 30; the axial adapter plate 31 is connected to the upper connecting plate 28 of the bearing; the axial supports 29 are evenly distributed in an annular shape and installed on the lower surface of the upper connecting plate 28 of the bearing; there is a cylindrical groove under the axial support 29, and the plunger 11 is installed by interference fit; the plunger 11 is connected to the three-dimensional force sensor connecting plate 24, keeping it tending to be horizontal, and can still rotate flexibly after the lower shaft is subjected to force; the three-dimensional force sensor 23 is connected to the lower surface of the three-dimensional force sensor connecting plate 24; the target axis part 22 is connected to the three-dimensional force sensor 23; the lower surface of the spherical bearing support shaft 25 is connected to the three-dimensional force sensor connecting plate 24, and the spherical bearing support shaft 25 is provided with a stepped support, which is clamped at the lower end of the spherical bearing 26; the upper part of the spherical bearing support shaft 25 is connected to the spherical bearing clip 27, which clamps the spherical bearing 26 therein; the spherical bearing clip 27 does not contact other parts, so that the spherical bearing support shaft 25 can be suspended under the spherical bearing 26 and rotate freely within a certain angle; the upper surface of the spherical bearing 26 is connected to the boss on the bearing upper connecting plate 28 to prevent interference with the spherical bearing clip 27;

[0009] The passive compliance unit 35 of the shaft part measures force information through the three-dimensional force sensor 23; realizes XY axis rotation compliance through the spherical bearing 26; provides a return force to the rotation compliance through the plunger 11; and controls the target shaft part 22 to move downward through the Z axis motor 32.

[0010] Furthermore, the planar compliance ring 12 includes a ball motion groove 36, a retaining frame 37 and balls 38; a number of balls 38 are embedded in the corresponding grooves of the retaining frame 37, and the balls 38 are placed on the annular groove on the ball motion groove 36; the groove of the retaining frame 37 has the same shape as the annular groove of the ball motion groove 36 and is coaxially positioned; the retaining frame 37 is used to ensure the relative position between each ball 38 to prevent the ball 38 from escaping from the ball motion groove 36 during compliance movement; the ball motion groove 36 is coated with lubricating oil to reduce the movement resistance of the ball 38.

[0011] Furthermore, one of the hole clamping tools is provided with an elastic clamping mechanism, and the elastic clamping part is pushed out by screwing a top screw into the lateral hole of the hole clamping tool to clamp the target hole part 19.

[0012] Furthermore, the flexible limit ring 21 has four holes evenly distributed in a ring shape, through which the limit ring support shaft 10 passes, and the flexible limit ring 21 is fixed by the fixing ring 4 to the same plane position as the hole part mounting plate 17; the flexible limit ring 21 limits the movement range of the floating hole part mounting plate 17 to prevent it from slipping out due to excessive movement range.

[0013] A method for active and passive compliant automatic assembly of micro-gap shaft hole parts, comprising the following steps:

[0014] S1: The Z-direction motor 32 in the shaft part compliance unit 35 is fixed to an external device, and the shaft part compliance unit 35 carries the target shaft part 22 to a fixed position; the target hole part 19 is positioned by the XY-direction motion slide 1 in the active adjustment unit 33 so that the target shaft part 22 is aligned with the target hole part 19;

[0015] S2: The Z-axis motor 32 in the shaft component compliance unit 35 moves downward until the shaft component 22 comes into contact with the target hole component 19;

[0016] S3: When the target shaft part 22 comes into contact with the target hole part 19, the hole-shaft assembly begins; the Z-axis motor 32 moves downward; the hole part mounting plate 17 located on the flat compliance ring 12 in the hole part compliance unit 34 slides slightly in the plane; the target shaft part 22 deflects; and the assembly continues.

[0017] S4: When the target shaft part 22 and the target hole part 19 are in a stuck state, the spring 6 is compressed in the longitudinal direction, and the active adjustment unit 33 adjusts the posture according to the force information to reduce the contact force. When the shaft-hole contact force calculated by the axial force sensor 14 and the three-dimensional force sensor 23 is greater than the set second threshold, the movement of the Z-axis motor 32 is stopped and adjustment is performed;

[0018] S5: When the Z-axis motor 32 moves to the specified position and when the shaft-hole contact force calculated by the axial force sensor 14 and the three-dimensional force sensor 23 is greater than the first threshold and less than the second threshold, it is considered that the target shaft part 22 is successfully inserted into the target hole part 19 to the required depth, and the shaft-hole assembly is completed.

[0019] The beneficial effects of the present invention are as follows: the present invention realizes the assembly of micro-gap shaft holes through flexible structural design. The active motion mechanism realizes the movement of the shaft into the hole through the slide, and the passive compliance structure includes a plane compliance ring, a spring and a plunger; the shaft holes are made horizontally flexible and the friction force is reduced through rolling friction, the shaft holes are made vertically flexible through the spring, and the shaft holes are made XY-axis rotationally flexible through the plunger and the spherical bearing; during the process of the shaft entering the hole, excessive assembly force and jamming are avoided; during assembly, active compliance is performed by controlling the active adjustment unit through obtaining force sensor information, and passive compliance is performed through the passive compliance structure; during active compliance adjustment, only a single parameter is adjusted, and the other parameter is adjusted by the passive flexible system, which reduces the accuracy requirement, simplifies the model complexity, and improves the assembly speed. The present invention realizes that the micro-gap shaft hole assembly device has a simple structure and a reasonable design, which can ensure the high efficiency of assembly. During the assembly process, the flexible assembly can buffer and disperse the force in the assembly process, reduce the stress concentration caused by assembly errors, and avoid deformation or damage of parts. By reducing assembly stress, it can reduce equipment wear and fatigue, thereby extending the service life of assembly equipment. It also has strong adaptability and can adapt to shaft and hole parts with different clearances. It is suitable for automated production lines of precision shaft and hole parts, meeting actual needs.

[0020] This invention achieves automated assembly of shaft-hole components with minute clearances by designing active and passive compliance structures. The active adjustment unit achieves alignment via an XY slide and a motion turntable, while the passive compliance unit, using structures such as balls, retaining rings, and springs, provides multi-directional compliance, reducing assembly forces. This invention avoids component damage and jamming, ensuring smooth and efficient shaft-hole assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the active adjustment unit of the present invention;

[0022] Figure 2 This is a front view of the structure of the passive compliance unit of the hole part of the present invention;

[0023] Figure 3 It is a top view of the structure of the passive compliance unit of the hole part of the present invention;

[0024] Figure 4 This is a top view of the structure of the passive compliance unit of the shaft part of the present invention;

[0025] Figure 5 This is a schematic structural diagram of the passive compliance unit of the shaft part of the present invention.

[0026] Figure 6 It is a structural schematic diagram of the present invention.

[0027] Figure 7 Schematic diagram of the planar compliant ring structure of the present invention.

[0028] In the figure: 1-XY motion slide, 2-XY axis motion turntable, 3-turntable connecting plate, 4-fixed ring, 5-linear bearing, 6-spring, 7-spring guide shaft, 8-flexible guide shaft, 9-guide shaft support, 10-limiting ring support shaft, 11-plunger, 12-flat flexible ring, 13-flat flexible platform, 14-axial force sensor, 15-force sensor mounting platform, 16-spring lower platform, 17-hole part mounting plate, 18-first hole clamping tool, 19-target hole part, 20-second hole clamping tool Tools, 21-compliant limit ring, 22-target axis parts, 23-three-dimensional force sensor, 24-three-dimensional force sensor connecting plate, 25-spherical bearing support shaft, 26-spherical bearing, 27-spherical bearing clip, 28-bearing upper connecting plate, 29-axial support, 30-Z-axis slide connecting plate, 31-axial adapter plate, 32-Z-axis stepper motor, 33-active adjustment unit, 34-hole part passive compliance unit, 35-axis part passive compliance unit, 36-ball motion groove, 37-cage, 38-ball. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention is further described below with reference to the accompanying drawings and implementation plans.

[0030] The present invention provides an active and passive compliant automatic assembly device for shaft-hole parts with small gaps, comprising an active adjustment unit, a hole part passive compliance unit and a shaft part passive compliance unit, wherein the active adjustment unit is used to achieve hole alignment and active compliant posture adjustment during the shaft-hole assembly process; the hole part passive compliance unit is used to achieve passive compliance of the hole part during the assembly process; and the shaft part passive compliance unit is used to achieve longitudinal movement and passive compliance of the shaft part during the assembly process.

[0031] Active adjustment unit composition: It consists of an XY motion slide, an XY axis motion turntable and a connecting structure, which are used to adjust the X and Y plane positions of the hole parts and the flip adjustment of the hole posture to ensure that the hole parts are aligned with the shaft parts.

[0032] The passive compliance unit for hole components consists of springs, linear bearings, compliant guide shafts, planar compliance rings, and ball bearings. The springs provide Z-axis compliance, while the planar compliance rings provide X- and Y-axis compliance, as well as Z-axis rotational compliance. Force sensors monitor assembly forces to prevent them from exceeding a set threshold.

[0033] The passive compliance unit for shaft components consists of a 3D force sensor, spherical bearings, and a motor, providing rotational compliance in the X and Y axes, as well as Z-axis motion. During assembly, the 3D force sensor monitors the assembly forces between the shaft and the bore, while the spherical bearings provide rotational freedom for the shaft.

[0034] The following is a specific embodiment of an active and passive compliance automatic assembly device for shaft and hole parts with a small gap, including an active adjustment unit 33, a hole part passive compliance unit 34 and a shaft part passive compliance unit 35;

[0035] The active adjustment unit 33 provides active motion for adjusting the position of the hole part and completes the position adjustment of the target hole part. It includes an XY motion slide 1, an XY axis motion turntable 2, and a connecting plate 3 on the turntable. The XY motion slide 1 is used to adjust the XY plane position of the hole part. Its lower surface is connected to the connecting workbench via threads, and its upper surface is connected to the XY axis motion turntable 2 via threads. The XY axis motion turntable 2 provides a turning force for hole posture adjustment and has an internal threaded hole on its upper surface, which is connected to the connecting plate 3 on the turntable via four symmetrically distributed threads. The connecting plate 3 on the turntable connects the active adjustment unit 33 and the hole part passive compliance unit 34. The connecting plate 3 on the turntable is connected to the platform 16 below the spring via four threads evenly distributed on the upper surface of the connecting plate 3 on the turntable, thereby enhancing the stability of the device.

[0036] The passive compliance unit 34 of the hole part includes a fixing ring 4, a linear bearing 5, a spring 6, a spring guide shaft 7, a compliance guide shaft 8, a guide shaft support 9, a limit ring support shaft 10, a plunger 11, a planar compliance ring 12, a planar compliance platform 13, an axial force sensor 14, a force sensor mounting platform 15, a platform below the spring 16, a hole part mounting plate 17, a first hole clamping tool 18, a target hole part 19, a second hole clamping tool 20, and a compliance limit ring 21; the spring guide shaft 7 is fixed to the platform below the spring 16 by a threaded connection; the spring 6 is sleeved on the spring guide shaft 7 to prevent the spring 6 from radial movement, the force sensor mounting platform 15 is pressed on top of the spring 6, and the spring 6 always remains in a compressed state to provide longitudinal flexibility during the hole assembly process. Compliance; the linear bearings 5 ​​are evenly distributed in an annular shape and fixed on the platform 16 below the spring; the linear bearings 5 ​​are connected to the guide shaft 8, and the guide shaft 8 is fixed on the guide shaft support 9; the guide shaft support 9 is evenly distributed in an annular shape and fixed on the force sensor mounting platform 15, and the cooperation between the guide shaft 8 and the linear bearings 5 ​​ensures that the force sensor mounting platform 15 can only slide up and down along the guide shaft 8 under the support of the spring 6; the axial force sensor 14 is evenly distributed in an annular shape and fixed on the force sensor mounting platform 15 below; a groove is provided above the axial force sensor 14, and the plunger 11 is evenly distributed in an annular shape and embedded in the groove above the corresponding axial force sensor 14 through interference fit, and the plunger 11 only transmits axial force to the axial force sensor 11; the plunger 11 is evenly distributed in an annular shape and installed on the plane compliance through interference fit There is a corresponding cylindrical groove below the platform 13; there is also a uniformly distributed cylindrical groove above the flat flexible platform 13, in which the flat flexible ring 12 is placed with a clearance fit; the flat flexible ring 12 is composed of a ball motion groove 36, a retainer 37, and a ball 38; 16 balls 38 are embedded in the corresponding grooves of the retainer 37, and the balls 38 are placed on the annular grooves on the ball motion groove 36. The retainer 37 is used to ensure the relative position of each ball 38 to prevent the balls 38 from escaping from the ball motion groove 36 during the flexible movement. The groove is coated with lubricating oil to reduce the movement resistance of the balls 38; the hole part mounting plate 17 is placed above the flat flexible ring 12, and there is rolling friction between the hole part mounting plate 17 and the flat flexible platform 13, providing lateral flexibility during the shaft hole assembly process. Compliance; Due to the small gap between the shaft holes, a ventilation groove is provided on the upper surface of the hole part mounting plate 17 to connect the air pressure inside and outside the hole of the hole part; The first hole clamping tool 18 and the second hole clamping tool 20 are symmetrically installed on the upper surface of the hole part mounting plate 17, and the target hole part 19 is clamped between the first hole clamping tool 18 and the second hole clamping tool 20. The second hole clamping tool 20 is provided with an elastic clamping mechanism, and the elastic clamping part is ejected by screwing a top screw into the hole to form a clamp on the target hole part 19; A flexible limiting ring 21 is sleeved on the outer periphery of the hole part mounting plate 17, and the flexible limiting ring 21 has four holes evenly distributed in an annular shape, and the limiting ring support shaft 10 passes through it, and then the flexible limiting ring 21 is fixed by the fixing ring 4 in the same plane position as the hole part mounting plate 17;The flexible limiting ring 21 limits the range of motion of the floating hole component mounting plate 17 to prevent it from sliding out due to excessive range of motion;

[0037] The passive compliance unit 35 of the shaft part includes a target shaft part 22, a three-dimensional force sensor 23, a three-dimensional force sensor connecting plate 24, a spherical bearing support shaft 25, a spherical bearing 26, a spherical bearing clip 27, a bearing upper connecting plate 28, an axial support 29, a Z-axis slide connecting plate 30, an axial adapter plate 31, and a Z-axis stepping motor 32; the target shaft part 22 is connected to the lower surface of the three-dimensional force sensor 23; the upper surface of the three-dimensional force sensor 23 is connected to the three-dimensional force sensor connecting plate 24; the lower surface of the spherical bearing support shaft 25 is connected to the three-dimensional force sensor connecting plate 24, and the spherical bearing support shaft 25 has a stepped support clamped on the lower end of the spherical bearing 26; the spherical bearing support shaft 25 is connected to the spherical bearing clip 27 through a thread to clamp the spherical bearing 26 therein, and the above-mentioned spherical bearing clip 27 does not contact other parts, so that the spherical bearing The surface bearing support shaft 25 can be suspended under the spherical bearing 26 and rotate freely within a certain angle; the upper surface of the spherical bearing 26 is connected to the boss on the bearing upper connecting plate 24 to prevent interference with the spherical bearing clip 27; the axial support 29 is evenly distributed in an annular shape and installed on the lower surface of the bearing upper connecting plate 28; there is a cylindrical groove under the axial support 29, and the plunger 11 is installed in the corresponding groove by interference fit. The above-mentioned plunger 11 is used to keep the three-dimensional force sensor connecting plate 24 tending to be horizontal, and it can still rotate flexibly after the lower shaft is subjected to force; the bearing upper connecting plate 28 is connected under the axial adapter plate 31; the rear side of the axial adapter plate 31 is connected to the Z-axis stepper motor 32 by a thread; a Z-axis slide connecting plate 30 is sandwiched between the two, and a limit is provided under the Z-axis slide connecting plate 30 to ensure that the lower surface of the axial adapter plate 31 is parallel to the lower surface of the Z-axis stepper motor 32 during installation;

[0038] Taking the automatic assembly process of shaft holes with small gaps as an example, the specific implementation steps of the present invention are described in combination with the technical solution and the accompanying drawings.

[0039] A device and method for active and passive compliant automatic assembly of micro-gap shaft hole parts, comprising the following steps:

[0040] S1: Alignment: The passive compliance unit of the shaft part carries the target shaft part to the initial position, and the hole part is adjusted to the alignment state through the active adjustment unit.

[0041] The Z-axis stepper motor 32 in the passive compliance unit 35 of the shaft part is fixed on an external device such as a collaborative robot, and the passive compliance unit 35 of the shaft part carries the target shaft part 22 to a fixed position; the target hole part 19 is clamped between the first hole clamping tool 18 and the second hole clamping tool 20, and the elastic clamping part is pushed out by screwing a top screw into the hole of the second hole clamping tool 20 to clamp the target hole part 19; the XY motion slide 1 in the active adjustment unit 33 adjusts the position according to the position information of the target shaft part 22 obtained in advance, so that the target hole part 19 moves to the specified position; the target shaft part 22 is aligned with the target hole part 19;

[0042] S2: Initial contact: The Z-axis motor starts, causing the shaft part to move downward until it contacts the hole part.

[0043] The Z-axis stepper motor 32 in the shaft part passive compliance unit 35 moves downward, according to the readings of the axial force sensor 14 in the hole part passive compliance unit 34 and the three-dimensional force sensor 23 in the shaft part passive compliance unit 35 until the target shaft part 22 comes into contact with the target hole part 19;

[0044] S3: Compliant assembly: When the shaft part contacts the hole part, the passive compliance unit of the hole part slides slightly under the action of the ball, and the posture of the shaft part is adjusted accordingly, and the assembly continues.

[0045] When the target shaft part 22 comes into contact with the target hole part 19, the shaft-hole assembly begins; the Z-axis stepper motor 32 moves further downward; since the gap between the shaft holes is 5um, the target shaft part 22 and the target hole part 19 are prone to getting stuck; when the error between the axes of the target shaft part 22 and the target hole part 19 is small; due to rolling friction between the hole part mounting plate 17 located on the plane compliance ring 12 in the hole part passive compliance unit 34, the hole part mounting plate 17 undergoes a small plane sliding; since the target shaft part 22 is subjected to force, the various plungers 11 under the axial support 29 in the shaft part passive compliance unit 35 produce different compression amounts, and the target shaft part 22 posture deflects; the assembly continues

[0046] S4: Jam Detection and Adjustment: During assembly, if a jam occurs between the shaft and the hole, the spring compresses, and the active adjustment unit adjusts its position based on information from the 3D force sensor and the axial force sensor to reduce the assembly force between the shaft and the hole. If the assembly force exceeds a set threshold, the Z-motor stops moving, and the active adjustment unit adjusts the angle between the shaft and the hole based on information from the 3D force sensor and the axial force sensor until the assembly force falls below the predetermined threshold, allowing assembly to continue.

[0047] When the target shaft part 22 and the target hole part 19 are in a stuck state, as the Z-axis stepper motor 32 moves, the hole part mounting plate 17 in the hole part passive compliance unit 34 compresses the spring 6 under the guidance of the compliance guide shaft 8; this pressure is reflected on the force sensor, and the contact force between the target shaft part 22 and the target hole part 19 is judged according to the readings of the axial force sensor 14 and the three-dimensional force sensor 23; if the contact force is greater than the threshold 1 and less than the threshold 2; the XY-axis motion slide 1 and the XY-axis motion turntable 2 in the active adjustment unit 33 are adjusted according to the force information, and only the target shaft part 22 and the hole part 19 are adjusted. The included angle between the axes of the target hole part 19; when the included angle between the axes is less than a certain value, the two end the blocking state, the spring 6 releases the compression amount so that the contact force between the two is always less than the threshold value 2; if the contact force is greater than the threshold value 2, the Z-axis stepper motor 32 stops moving, and the XY-axis motion slide 1 and the XY-axis motion turntable 2 in the active adjustment unit 33 adjust the posture according to the force information, and only adjust the included angle between the axes of the target axis part 22 and the target hole part 19; when the included angle between the axes is less than a certain value, the two end the blocking state, the spring 6 releases the compression amount so that the contact force between the two is less than the threshold value 1, and the Z-axis stepper motor 32 continues to move downward;

[0048] S5: Assembly completed: When the shaft part is inserted into the hole part to a predetermined depth and the assembly force is within the allowable range, the assembly is completed.

[0049] When the Z-axis stepper motor 32 moves to the specified position and the contact force is greater than threshold 1 and less than threshold 2, it is considered that the target shaft part 22 is successfully inserted into the target hole part 19 to the required depth, and the shaft-hole assembly is completed.

Claims

1. A device for active and passive flexible automatic assembly of small gap shaft hole parts, characterized in that: The micro-gap shaft hole part active and passive compliance automatic assembly device comprises an active adjustment unit (33), a hole part passive compliance unit (34) and a shaft part passive compliance unit (35), which are connected in sequence; The active adjustment unit (33) provides power for adjusting the position of the hole part and completes the posture adjustment of the target hole part (19) by combining force and torque information; the active adjustment unit (33) includes an XY-axis motion slide (1), an XY-axis motion turntable (2) and a connecting plate (3) on the turntable, and the three are connected in sequence; The hole part passive compliance unit (34) realizes the passive compliance of the target hole part (19) during the assembly process; the hole part passive compliance unit (34) includes a spring (6), a linear bearing (5) and a guide shaft (8); one end of the spring (6) is connected to the platform (16) below the spring, and the other end is connected to the force sensor mounting platform (15), and the spring (6) is in a compressed state; the linear bearing (5) is evenly distributed on the platform (16) below the spring; one end of the guide shaft (8) is connected to the linear bearing (5), and the other end is fixed to the force sensor mounting platform (15) through a guide shaft support (9); the force sensor mounting platform (15) slides up and down under the support of the spring (6) through the guide shaft (8) and the linear bearing (5); the axial force sensor (14) is evenly distributed on the force sensor mounting platform (15); a groove is provided above the axial force sensor (14); cylindrical grooves are provided above and below the planar compliance platform (13); the plunger (11) is fitted by an interference fit The plunger (11) transmits axial force only to the axial force sensor (14); the plane compliance ring (12) is clearance-fitted in the cylindrical groove above the plane compliance platform (13); the hole part mounting plate (17) is placed above the plane compliance ring (12); rolling friction occurs between the hole part mounting plate (17) and the plane compliance platform (13), providing lateral compliance during the shaft hole assembly process; the upper surface of the hole part mounting plate (17) is provided with a through hole. An air groove is provided to connect the air pressure inside and outside the hole part; two hole clamping tools are symmetrically installed on the upper surface of the hole part mounting plate (17); the target hole part (19) is clamped between the two hole clamping tools and mounted on the hole part mounting plate (17); a flexible limiting ring (21) is sleeved on the outer periphery of the hole part mounting plate (17); the flexible limiting ring (21) is fixed to the fixing ring (4) through the limiting ring support shaft (10), ensuring that the relative distance between the platform (16) below the spring and the hole part mounting plate (17) is constant; The hole part passive compliance unit (34) is connected to the platform (16) below the spring through the spring (6) to achieve Z-direction compliance; the Z-direction compliance is guided by the linear bearing (5) and the guide shaft (8); the torque information is measured by the annularly evenly distributed axial force sensor (14); the X- and Y-direction horizontal compliance and the Z-direction rotational compliance are achieved through the plane compliance ring (12); the shaft part passive compliance unit (35) achieves the longitudinal movement and passive compliance of the target shaft part (22) during the assembly process; The passive compliance unit (35) of the shaft part includes a three-dimensional force sensor (23), a spherical bearing (26), a bearing upper connecting plate (28), an axial support (29), a Z-axis slide connecting plate (30), an axial adapter plate (31) and a Z-axis stepping motor (32); the Z-axis stepping motor (32) is connected to the axial adapter plate (31) via the Z-axis slide connecting plate (30); the axial adapter plate (31) is connected to the bearing upper connecting plate (28); the axial support (29) is evenly distributed in an annular shape on the lower surface of the bearing upper connecting plate (28); a cylindrical groove is provided under the axial support (29), and a plunger (11) is installed in an interference fit; the plunger (11) is connected to the three-dimensional force sensor connecting plate (24) to keep it tending to be horizontal, and can still rotate with flexibility after the target shaft part (22) below is subjected to force; The three-dimensional force sensor (23) is connected to the lower surface of the three-dimensional force sensor connecting plate (24); the target axis part (22) is connected to the three-dimensional force sensor (23); the lower surface of the spherical bearing support shaft (25) is connected to the three-dimensional force sensor connecting plate (24), and the spherical bearing support shaft (25) is provided with a stepped support, which is clamped on the lower end of the spherical bearing (26); the upper part of the spherical bearing support shaft (25) is connected to the spherical bearing clip (27), which clamps the spherical bearing (26) therein; the spherical bearing clip (27) does not contact other parts, so that the spherical bearing support shaft (25) can be suspended under the spherical bearing (26) and rotate freely within a certain angle; the upper surface of the spherical bearing (26) is connected to the upper boss of the bearing upper connecting plate (28) to prevent the spherical bearing clip (27) from interfering; The passive compliance unit (35) of the shaft part measures force information through a three-dimensional force sensor (23); realizes XY-axis rotation compliance through a spherical bearing (26); provides a return force to the rotation compliance through a plunger (11); and controls the downward movement of the target shaft part (22) through a Z-axis stepping motor (32).

2. The active and passive compliant automatic assembly device for micro-gap shaft hole parts according to claim 1 is characterized in that: The planar compliant ring (12) includes a ball motion groove (36), a retaining frame (37) and a ball (38); a plurality of balls (38) are embedded in corresponding grooves of the retaining frame (37), and the balls (38) are placed on an annular groove on the ball motion groove (36); the groove of the retaining frame (37) and the annular groove of the ball motion groove (36) have the same shape and are coaxially positioned; the retaining frame (37) is used to ensure the relative position between each ball (38) to prevent the ball (38) from escaping from the ball motion groove (36) during compliant movement; the ball motion groove (36) is coated with lubricating oil to reduce the movement resistance of the ball (38).

3. The active and passive compliant automatic assembly device for micro-gap shaft hole parts according to claim 1 or 2, characterized in that: One of the hole clamping tools is provided with an elastic clamping mechanism, and the elastic clamping part is pushed out by screwing a top screw into the lateral hole of the hole clamping tool to clamp the target hole part (19).

4. The active and passive compliant automatic assembly device for micro-gap shaft hole parts according to claim 3 is characterized in that: The flexible limiting ring (21) has four holes evenly distributed in a ring shape, through which the limiting ring support shaft (10) passes, and the flexible limiting ring (21) is fixed by the fixing ring (4) to the same plane position as the hole part mounting plate (17); the flexible limiting ring (21) limits the movement range of the floating hole part mounting plate (17) to prevent it from sliding out due to excessive movement range.

5. A method for active and passive compliant automatic assembly of small gap shaft hole parts, characterized in that: The active and passive compliant automatic assembly device for small gap shaft hole parts according to any one of claims 1 to 4 is implemented, comprising the following steps: S1: The Z-axis stepper motor (32) in the passive compliance unit (35) of the shaft part is fixed on an external device, and the passive compliance unit (35) of the shaft part carries the target shaft part (22) to move to a fixed position; the target hole part (19) is adjusted in position by the XY motion slide (1) in the active adjustment unit (33) so that the target shaft part (22) is aligned with the target hole part (19); S2: The Z-axis stepper motor (32) in the passive compliance unit (35) of the shaft part moves downward until the target shaft part (22) comes into contact with the target hole part (19); S3: When the target shaft part (22) comes into contact with the target hole part (19), the hole-shaft assembly begins; the Z-axis stepper motor (32) moves downward; the hole part mounting plate (17) located on the plane compliance ring (12) in the hole part passive compliance unit (34) undergoes a small plane sliding; the target shaft part (22) deflects; and the assembly continues; S4: When the target shaft part (22) and the target hole part (19) are in a stuck state, the spring (6) is compressed in the longitudinal direction, and the active adjustment unit (33) adjusts the posture according to the force information to reduce the contact force. When the shaft-hole contact force calculated by the axial force sensor (14) and the three-dimensional force sensor (23) is greater than the set second threshold, the movement of the Z-axis stepper motor (32) is stopped and adjustment is performed; S5: When the Z-axis stepper motor (32) moves to the specified position and the shaft-hole contact force calculated by the axial force sensor (14) and the three-dimensional force sensor (23) is greater than the first threshold value and less than the second threshold value, it is considered that the target shaft part (22) is successfully inserted into the target hole part (19) to the required depth, and the shaft-hole assembly is completed.

Images