Active and passive flexible automatic assembling device and method for small-gap shaft hole part

Abstract

The invention belongs to the technical field of precision assembly, and discloses an active and passive flexible automatic assembly device and method for a micro-gap shaft hole part. The automatic assembling device for the tiny gap hole shaft comprises an active adjusting unit, a hole part passive compliance unit and a shaft part passive compliance unit. The active adjusting unit provides power for adjusting the position of the hole part, and posture adjustment of the target hole part is completed. The hole part passive compliance unit achieves passive compliance of a hole in the assembling process, longitudinal passive compliance of the hole is achieved through an internal guide shaft and a linear bearing, and plane passive compliance of the hole is achieved through a plane compliance ring. The shaft part passive compliance unit achieves longitudinal movement of the shaft in the assembling process and achieves passive compliance of the posture of the shaft through an inner plunger. During assembly, only the included angle between holes and shafts is adjusted during adjustment through active and passive mixed compliant control, hole and shaft position deviation is adjusted through following of a flexible system, the precision requirement is lowered, the model complexity is simplified, the assembly speed is increased, and stress between parts is reduced.

Description

Technical Field

[0001] The 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-hole assembly is an important process in the field of assembly. At present, precision shaft-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 production capacity, and it is difficult to ensure the consistency of assembly. In the process of precision assembly of shaft-holes with small gaps, due to the small gap and small allowable contact force, there are often jams between shafts and holes, excessive contact force, and even damage to parts during assembly, which will seriously affect the final assembly quality of parts. In actual situations, the force state is more complicated, and there are sensor errors, gravity compensation errors, mechanical installation errors, processing errors, etc., which require complex models and higher adjustment accuracy as support. Therefore, integrating active and passive compliance control systems in precision shaft-hole assembly equipment directly promotes the high automation development of assembly of shaft-hole parts with small gaps. Summary of the invention

[0003] In view of 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 active and passive compliance automatic assembly device for shaft and hole parts with a small gap, 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 completes the posture adjustment of the target hole part 19 by combining the force and torque information; 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 in an annular manner 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 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 in an annular manner 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 flexible platform 13; the plunger 11 is fixed to the recess by interference fit The piston 11 transmits axial force only to the axial force sensor 14; the plane compliance ring 12 is gap-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; there is rolling friction between the hole part mounting plate 17 and the plane compliance platform 13, providing lateral flexibility during the shaft hole assembly process; a venting groove is provided on the upper surface of the hole part mounting plate 17 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, 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 evenly distributed axial force sensor 14; the X- and Y-direction horizontal compliance and 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;

[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 connecting plate 28 on the bearing; the axial support 29 is evenly installed in an annular manner on the lower surface of the connecting plate 28 on 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 to keep it 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 shaft 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, and the spherical bearing 26 is clamped therein; the spherical bearing clip 27 does not contact with 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 the spherical bearing clip 27 from interfering;

[0009] The shaft part passive compliance unit 35 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 target shaft part 22 to move downward through a Z axis motor 32 .

[0010] Furthermore, the planar compliance ring 12 includes a ball motion groove 36, a retaining frame 37 and a ball 38; a plurality of balls 38 are embedded in the corresponding grooves of the retaining frame 37, and the balls 38 are placed on the annular grooves on the ball motion groove 36; the grooves of the retaining frame 37 have the same shape as the annular grooves of the ball motion groove 36 and are coaxially positioned; the retaining frame 37 is used to ensure the relative positions of the balls 38 to prevent the balls 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 balls 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 be in 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 on an external device, and the shaft part compliance unit 35 carries the target shaft part 22 to move to a fixed position; the target hole part 19 is position-adjusted 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 part compliance unit 35 moves downward until the shaft part 22 comes into contact with the target hole part 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 on the plane compliance ring 12 in the hole part compliance unit 34 undergoes a small plane sliding; 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 shaft holes with small gaps through the flexible structure 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 have horizontal compliance and reduce friction through rolling friction, the shaft holes have vertical compliance through the spring, and the shaft holes have XY axis rotation compliance through the plunger and the spherical bearing; in the process of the shaft entering the hole, excessive assembly force and jamming are avoided; during assembly, the active adjustment unit is controlled by obtaining force sensor information to perform active compliance, 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 requirements, simplifies the model complexity, and improves the assembly speed. The present invention realizes that the assembly device of the shaft hole with small gaps 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, the wear and fatigue of equipment can be reduced, 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 the automated production line of precision shaft and hole parts, meeting actual needs.

[0020] The present invention realizes the automatic assembly of shaft hole parts with small gaps by designing active and passive compliance structures. The active adjustment unit realizes alignment through the XY slide and the motion turntable, while the passive compliance unit provides multi-directional compliance through structures such as balls, limit rings, and springs to reduce the assembly force during the assembly process. The present invention avoids part damage and jamming, and ensures the stability and efficiency of the shaft hole assembly process. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] Figure 2 It is a structural front view 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 It is a top view of the structure of the passive compliance unit of the shaft part of the present invention;

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

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

[0027] Figure 7 It is a 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 table, 16-spring lower platform, 17-hole part mounting plate, 18-first hole clamping tool, 19-target hole part, 20-second hole clamp 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 in conjunction with the accompanying drawings and implementation plans.

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

[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 of the hole part consists of springs, linear bearings, compliance guide shafts, planar compliance rings and balls. The spring provides Z-axis compliance, the planar compliance ring provides X and Y-axis compliance, and Z-axis rotational compliance. The force sensor is used to monitor the assembly force to prevent the assembly force from exceeding the set threshold.

[0033] The passive compliance unit of the shaft part consists of: three-dimensional force sensors, spherical bearings, motors and other components to provide the shaft part with X and Y axis rotation compliance and Z direction movement. During the assembly process, the three-dimensional force sensor is used to monitor the assembly force of the shaft part and the hole part, and the spherical bearing provides the shaft part with rotational freedom.

[0034] The following is a specific embodiment, a micro-gap shaft hole part active and passive compliance automatic assembly device, 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, which 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. The lower surface is connected to the connecting workbench through threads, and the upper surface is connected to the XY axis motion turntable 2 through threads; the XY axis motion turntable 2 provides a flipping 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 through 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, and the connecting plate 3 on the turntable is connected to the platform 16 below the spring through four threads evenly distributed on the upper surface of the connecting plate 3 on the turntable to enhance the stability of the device;

[0036] The hole part passive compliance unit 34 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 the 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 bearing 5 is evenly fixed in an annular shape on the platform 16 below the spring; the linear bearing 5 is 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 fixed in an annular shape on the force sensor mounting platform 15, and the cooperation between the guide shaft 8 and the linear bearing 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 fixed in an annular shape on the force sensor mounting platform 15 below; a groove is provided above the axial force sensor 14, and the plunger 11 is evenly embedded in the groove above the corresponding axial force sensor 14 through interference fit, and the plunger 11 only transmits the axial force to the axial force sensor 11; the plunger 11 is evenly installed on the plane through interference fit in an annular shape There is a corresponding cylindrical groove below the platform 13; there is also an evenly 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 movement 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 movement 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 movement groove 36 during the flexible movement. Lubricating oil is applied to the groove 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 to provide 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 pushed out by screwing a top screw into the hole to clamp the target hole part 19; A flexible limit ring 21 is sleeved on the periphery of the hole part mounting plate 17, and the flexible limit ring 21 has four holes evenly distributed in an annular shape, and the limit ring support shaft 10 passes through it, and then the flexible limit ring 21 is fixed by the fixing ring 4 in the same plane position as the hole part mounting plate 17;The compliant limiting ring 21 limits the movement range of the floating hole component mounting plate 17 to prevent it from slipping out due to excessive movement range;

[0037] The shaft part passive compliance unit 35 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 there is a stepped support on the spherical bearing support shaft 25 that is 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 upper connecting plate 24 of the bearing to prevent interference with the spherical bearing clip 27; the axial support 29 is evenly installed in an annular manner 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 in the corresponding groove by interference fit. The above 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 upper connecting plate 28 of the bearing 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 threads; 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 based on small gaps as an example, the specific implementation steps of the present invention are described in combination with the technical solution and the 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 move 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-axis 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, 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; due to the force on the target shaft part 22, the various plungers 11 under the axial support 29 in the shaft part passive compliance unit 35 produce different compression amounts, and the posture of the target shaft part 22 sways; the assembly continues

[0046] S4: Jam detection and adjustment: During the assembly process, if the shaft part and the hole part are jammed, the spring will be compressed, and the active adjustment unit will adjust the posture based on the information of the three-dimensional force sensor and the axial force sensor to reduce the assembly force between the shaft and the hole. When the assembly force exceeds the set threshold, the movement of the Z-axis motor is stopped, and the active adjustment unit adjusts the angle between the axis of the hole and the shaft according to the information of the three-dimensional force sensor and the axial force sensor until the assembly force is less than the preset threshold, and the assembly continues.

[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 target hole part 19 axis angle; when the axis angle 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 axis angle between the target axis part 22 and the target hole part 19; when the axis angle 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. An active and passive compliant automatic assembly device for small gap shaft hole parts. It is characterized in that The micro-gap shaft hole component active and passive compliance automatic assembly device comprises an active adjustment unit (33), a hole component passive compliance unit (34) and a shaft component 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 position adjustment of the target hole part (19) by combining force and torque information; the active adjustment unit (33) includes an XY motion slide table (1), an XY axis motion turntable (2) and a connecting plate (3) on the turntable, which 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 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 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 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 The plunger (11) is fixed between the groove and the cylindrical groove; the plunger (11) transmits the axial force only to the axial force sensor (14); the plane compliance ring (12) is loosely 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); there is rolling friction 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 vent The groove connects 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 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), so as to ensure 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 by 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 shaft component passive compliance unit (35) comprises 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 installed in an annular manner 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 by 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 and have flexibility after the target shaft component (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 shaft 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 clamp (27), and the spherical bearing (26) is clamped therein; the spherical bearing clamp (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 clamp (27) from interfering; The shaft part passive compliance unit (35) 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 target shaft part (22) to move downward through a Z axis motor (32).

2. The active and passive compliant automatic assembly device for micro-gap shaft hole parts according to claim 1, It is characterized in that The plane compliant ring (12) comprises 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 located; the retaining frame (37) is used to ensure the relative position between the balls (38) to prevent the balls (38) from escaping from the ball motion groove (36) during compliant motion; the ball motion groove (36) is coated with lubricating oil to reduce the movement resistance of the balls (38).

3. The active and passive compliant automatic assembly device for micro-gap shaft hole parts according to claim 1 or 2, It is 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, It is characterized in that 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 be in 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.

5. A method for active and passive compliant automatic assembly of small gap shaft hole parts. It is characterized in that The method is realized by the active and passive compliant automatic assembly device for small gap shaft hole parts according to any one of claims 1 to 4, comprising the following steps: S1: The Z-direction motor (32) in the shaft part compliance unit (35) is fixed on an external device, and the shaft part compliance unit (35) carries the target shaft part (22) to move to a fixed position; the target hole part (19) is positionally adjusted 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); 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); 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 plane compliance ring (12) in the hole part compliance unit (34) undergoes a small plane sliding; the posture of 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 motor (32) is stopped and adjustment is performed; 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 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.

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