JPH10180576A - Assembling method and device for joint cross coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give a constant preload certainly to the end face of a joint cross shaft part using a spreading reaction force of a yoke. SOLUTION: A hook 41 to spread a yoke and a pressure fitting rod 51 for a bearing case are driven by servo motors 81 and 52. The spreading position of the hook 41 and the advancing position of the rod 51 are specified on the basis of the loads applied to the servo motors 81 and 52. Even in the case there is dispersion in the rigidity of the yoke, the overall length of the joint cross, and the thickness of the bearing case bottom part, it is possible to certainly align the yoke with the cruciform shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In the present invention, a bottomed cylindrical bearing case for supporting each shaft portion of a cross shaft is disposed in a bearing hole of an opposite arm of a yoke of two coupled shafts. The present invention relates to an assembling method and an assembling apparatus of a type in which a reaction force for expanding a yoke is exerted on an end face of a shaft via a bottom of a bearing case.

[0002]

2. Description of the Related Art In assembling the cross shaft joint, when a bearing is press-fitted into a bearing hole of a yoke and fixed, the inner bottom surface of the bearing case and the end surface of the shaft portion of the cross shaft are fixed. It is necessary to provide an appropriate preload in the meantime. However, since the press-fitting of the bearing is performed from the outer surface of the yoke, the opposing arm of the yoke is elastically deformed in a direction to reduce the gap due to the press-fitting. Therefore, when the press-fitting is released after the bearing is fixed, the yoke is restored. In this case, the preload applied between the inner bottom surface of the case and the end surface of the shaft of the cross shaft is not only eliminated, but also a slight gap is generated between them.

In order to eliminate such inconvenience, when the bearing is press-fitted, the gap between the opposing arms of the yoke is expanded by a certain size, the bearing is fixed to the yoke in the expanded state, and after the fixing, the expansion is released. Then, there is provided an assembling method in which the opposing arm is elastically returned to the original state, and a preload is applied between the inner bottom surface of the bearing case and the shaft end surface of the cross shaft.

[0004] Incidentally, the interval between the opposing surfaces of the opposing arms of the yoke varies considerably in manufacturing. Therefore, when the hook is hooked on the opposing arm and the hook is expanded, if the stop position (that is, the expanded position) of the hook after expansion is kept constant, the amount by which the yoke is actually expanded is smaller. Differently, the preload varies.

Therefore, the hook is hooked between the opposing arms in a no-load state, and the hook is applied to the inner end surface of the opposing arm such that a weak force that hardly causes elastic deformation is applied from the hook to the inner end surface of the opposing arm. It is proposed that, after the yoke is centered by contacting the yoke, at the time of expansion, the hook is moved from the abutment position to an expansion position separated by a fixed stroke amount in the expansion direction to expand the hook. I have.

However, when a certain stroke amount is expanded as described above, the expansion torque of the yoke differs due to the difference in rigidity of the yoke, resulting in a variation in preload. On the other hand, conventionally, a press-fitting rod for press-fitting a bearing case into a bearing hole of a cross shaft has been configured to press-fit by moving a predetermined stroke amount from a position in contact with the bottom of the bearing case. For this reason, the actual press-fit dimensions vary due to variations in the overall length of each shaft portion of the cross shaft and the thickness of the bottom of the bearing case, resulting in variations in preload.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for assembling a cross joint capable of reliably obtaining a constant preload.

[0008]

To achieve the above object, a method of assembling a cross shaft joint according to the present invention is characterized in that a cross shaft joint is provided in a bearing hole of a facing arm of a yoke of two coupled shafts. A cross-shaped joint in which a bottomed cylindrical bearing case for supporting each of the shaft portions is arranged, and a reaction force for expanding the yoke is exerted on the end surface of the shaft portion via the bottom portion of the bearing case. In the assembling method, the expanding position of the hook for expanding the yoke is defined based on the stress applied to the hook when the yoke is expanded, and the rod for pressing the bearing case into the bearing hole of the opposite arm of the yoke is advanced. The position is defined based on the stress applied to the rod at the time of press-fitting.

[0009] In the above configuration, the expanding position of the hook is defined based on the stress of the hook at the time of expanding, so that the expanding torque of the yoke can be constant regardless of the rigidity of the yoke. In addition, since the rod advance position is determined based on the stress actually applied to the rod at the time of press-fitting, even if the overall length of the cross-shaft or the thickness of the bottom of the bearing case varies, the bottom of the bearing case may be varied. The center of the yoke and the center of the cross shaft can be accurately matched with each other, and the center of the yoke and the center of the cross shaft can be accurately matched.

According to a second aspect of the present invention, there is provided an assembling apparatus for a cross shaft joint having a bottomed cylindrical shape for supporting each shaft portion of a cross shaft in a bearing hole of an opposite arm of a yoke of two coupled shafts. In a cross-shaft joint assembling device in which a bearing case is arranged and a reaction force for expanding the yoke is exerted on the end face of the shaft via the bottom of the bearing case, the hook for expanding the yoke is expanded. Detects the load on the expansion servomotor that moves to the position and the load on the expansion servomotor when the yoke is expanded.
Means for controlling the expansion servomotor based on this load, a press-fit rod drive servomotor for advancing the rod for bearing case press-fitting, and a load applied to the press-fit rod drive servomotor at the time of bearing case press-fitting. Means for controlling the press-fit rod drive servomotor based on the

In the above configuration, the stress applied to the hook at the time of expansion is correlated with the load of the servomotor for expansion, and the stress applied to the rod at the time of press-fitting of the bearing case is correlated with the load of the servomotor driving the press-fit rod. Paying attention to the fact, the extended position of the hook and the extended position of the rod are defined according to the load of the servomotor. Therefore, regardless of the rigidity of the yoke, the expansion torque of the yoke can be kept constant. Also, even if the overall length of the shaft of the cross shaft or the thickness of the bottom of the bearing case varies, the bottom of the bearing case can be securely brought into close contact with the end surface of the shaft of the cross shaft, and the center of the yoke and the cross shaft The center can be accurately matched.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings. First, referring to FIG. 8 which is a perspective view of the cross shaft joint after assembly, a pair of coupled shafts 3 and 3 arranged coaxially are U-shaped and arranged with a phase shift of 90 ° from each other. It has a yoke 4. Referring to FIG. 8 and FIG. 9 which is a partially cutaway side view (corresponding to a cross section taken along line YY in FIG. 8) of a main part of the cross shaft joint during assembly,
A bearing case 7 is inserted into a bearing hole 6 provided in each of the arms 5, and the cross shaft 1 is inserted through the bearing case 7.
Each of the shaft portions 2 is supported.

The needle 8 rolls between the inner peripheral surface of the bearing case 7 and the outer peripheral surface of the shaft portion 2. In FIG. 9, the expanding hook 41 is hooked on the inner end surface 5 a of the arm 5, and the press-fit rod 51 presses the bottom 7 a of the bearing case 7 against the end surface 2 a of the shaft portion 2. A pair of caulking punches 61 raise a part of the inner peripheral surface of the bearing hole 6 and caulk the outer peripheral edge of the bearing case 7.

In FIG. 9, C1 is the center of the cross shaft 1, and C2 is the center between the opposing arms 5,5. Overall Configuration FIG. 3 is a schematic plan view of an assembly device (hereinafter simply referred to as an assembly device) of a cross joint according to an embodiment of the present invention.
Referring to FIG. 3, two pairs of assembly units A and A 'are arranged. Although not shown in FIG. 3, the cross shaft 1 is attached to a central position surrounded by the assembly units A and A '.
Corresponds to each shaft portion 2 of the cross shaft 1. One pair of assembling units A, A facing each other has a hook 4 for expanding corresponding to the yoke 4 opened upward as shown in FIG.
1 is directed downward, while the other pair of assembly units A ', A'
Is turned upward. The assembling unit A and the assembling unit A ′ differ only in the arrangement of the hook engaging / disengaging mechanism including the hook 41, and the other configurations are the same. Therefore, the following description will be made in accordance with the assembling unit A.

Referring to FIG. 1 which is a schematic side view of the assembling unit A, the assembling unit A includes a base 10 and a base 10 and an X direction toward the cross joint in the front-rear direction. A) a caulking unit 20 which is slidably supported and moved back and forth by a unit driving servomotor 81, and an expanding hook 41 which is hooked on the inner end surface 5a of the arm 5 (see FIG. 8). A hook engagement / disengagement mechanism 40 that moves up and down to engage and disengage with the inner end surface 5a of the arm 5 and a press-fit rod 51 for press-fitting the bearing case 7 into the bearing hole 6 include a press-fit rod drive servomotor 52. And a press-fitting mechanism 50 for moving back and forth in the front-rear direction. And a caulking mechanism 60 including a closing punch 61 includes, as principal components.

Base 10 and caulking unit 20 Referring to FIG. 1, the base 10 includes a bottom plate 11, a side plate 12, a rear plate 13, and a slide rail 14. The caulking unit 20 includes a movable bed 23, and a pair of front and rear sliders 21 is fixed to a lower portion of the movable bed 23. The sliders 21 are slidably supported in the front-rear direction by the slide rails 14 of the base 10. In addition, the movable bed 23
A mounting stay 22 is fixed to the lower part of the bracket. A ball nut 24 is attached to a lower portion of the attachment stay 22 so as to be able to move integrally back and forth.

On the other hand, the above-described caulking unit driving servomotor 81 is fixed to the rear plate 13 of the base 10. The caulking unit driving servomotor 81 has a ball screw 8 which is screwed through the ball nut 24 and penetrated.
2 are connected. When the caulking unit drive servo motor 81 drives the ball screw 82 to rotate, the slider 21
Is slid on the slide rail 14 so that the entire caulking unit 20 is moved forward and backward.
A bearing 83 is fixed to the lower surface of the slide rail 14 and rotatably supports the end of the ball screw 82.

A support 25 is fixed to a front portion of the upper surface of the movable bed 23, and a slide rail 26 extending forward and backward is fixed to a rear portion. This slide rail 2
6 is provided with a movable bed 27 slidably forward and backward, and a movable body 28 is fixed to the movable bed 27. A ball nut 33 screwed to the ball screw 55 of the press-fitting mechanism 50 is fixed inside the movable body 28.

On the other hand, on the front side of the support 25, a support 29 is fixed. An upper plate 30 and a lower plate 31 are fixed above and below the support 29, and a T-shaped member 43 is provided between the upper plate 30 and the lower plate 31 so as to be vertically slidable. At the front end of the T-shaped member 43, the above-described hook 41 for expanding is attached. A hook engaging / disengaging hydraulic cylinder 42 for vertically moving the T-shaped member 43 is fixed to the lower surface of the lower plate 31. Reference numeral 44 denotes a rod of the hook engaging / disengaging drive cylinder 42 which is connected to the T-shaped member 43 through the lower plate 31.

The hook engaging / disengaging drive cylinder 42 is
Is extended, the hook 41 is separated from the yoke 4, and when the rod 44 is shortened, the hook 41 is hooked on the yoke 4. Hook engaging / disengaging drive cylinder 4
2 and the T-shaped member 43, the hook disengaging mechanism 40
Is configured. Referring to FIGS. 5A and 5B, the expanding hook 41 is connected to a hook support 45 through a hook support 45.
The hook support 45 is attached to the T-shaped member 43 and a predetermined amount (for example, 0.1
(0.2 mm).
That is, the two bolts 43, 45 are fixed to the T-shaped member 43 and allow a head support 45 to slide in the front-rear direction, and a compression coil spring loosely fitted to the shaft of the bolt 46. And 47 are connected to each other. Therefore, when the T-shaped member 43 retreats together with the retraction of the caulking unit 20, the compression coil spring 47 is compressed in the range of the play e, and the hook 41 is pulled by the reaction force of the compression coil spring 47. When the play e exceeds the range, as shown in FIG. 5B, the hook 41 is pulled in a state where the T-shaped member 43 and the hook support 45 are in direct contact with each other. In addition, the above-mentioned bolt 46 is provided in the hole 4 formed in the hook support 45.
The compression coil spring 47 is interposed between the head 46a of the bolt 46 and the bottom of the hole 45a.

On the other hand, the proximity sensor 4 is attached to the T-shaped member 43.
When the proximity sensor 48 approaches a reference surface 49a of a reference body 49 fixed to the hook support 45 to a certain distance, the hook 4
1 is hooked on the yoke 4 and is determined to be normal. On the other hand, if the proximity sensor 48 does not approach the reference surface 49a to a certain distance irrespective of the retraction of the caulking unit 20, a defect such as the hook 41 not being hooked on the yoke 4 occurs for some reason. Therefore, the CPU 91 described later issues a signal to stop the driving of the unit driving servo motor 81.

A caulking advance / retreat driving cylinder 62 of a caulking mechanism 60 is fixed to the rear upper portion of the support 25. The caulking advance / retreat drive cylinder 62 moves the caulking punch 61 forward / backward via a cylindrical sleeve 63. Next, with reference to FIG. 2 which is a schematic plan view of the assembly unit A, the caulking unit 20 is provided with a pair of rods 32 which move integrally back and forth. Each rod 32 is fixed by a hydraulic clamp cylinder 90 as a lock mechanism fixed to the rear plate 13 of the base 10.
It is clamped when required, so that the caulking unit 2
The front and rear positions of 0 are locked. When the caulking mechanism 60 supported by the caulking unit 20 performs caulking, the ball screw 82 of the caulking unit 20 and the caulking unit drive servo motor 8
If it is received in step 1, they may be damaged or the durability may be reduced. On the other hand, in this embodiment, since the caulking reaction force is received by the rear plate 13 of the base 10 via the lock mechanism 90, unnecessary load is not applied to the ball screw 82 and the caulking unit drive servomotor 81.

[0023] With reference to the press-fitting mechanism 50 FIGS. 1 and 4, the press-fitting mechanism 50 includes a press-rod 51 penetrating the crimping punch 61 concentrically, the plurality of intermediate rods aligned coaxially to pressing the press-fitting rod 51 53, 54, the movable body 28 for pressing the pressing rod 54, and the press-fit rod drive servomotor 52 for driving the movable body 28 back and forth via a ball screw 55.

The intermediate rods 53 and 54 pass through a cylindrical rod 63 that presses a caulking punch 61. At the rear end of the intermediate rod 53 and the front end of the intermediate rod 54,
Cylindrical portions 57 and 58 are respectively formed, and these cylindrical portions 57 and 58 abut against each other. A compression coil spring 56 is housed in the tubular portions 57 and 58 so as to straddle the two portions 57 and 58.

In the prior art, since a long integrated press-fit rod is employed from the hydraulic cylinder for pressing drive, the caulking unit cannot move forward unless the press-fit rod advances, and the caulking unit does not move backward. Although there was a problem that the press-fitting rod could not be retracted, in the present embodiment, the plurality of rods 51, 53, 54 which can be separated from each other as described above.
Are coaxially arranged and used, so that the press-fit rod 51 and the caulking unit 20 can move independently of each other. That is, it is possible to drive each of the press-fit rod 51 and the caulking unit 20 without being particular about the driving order, and it is also possible to drive both simultaneously, and as a result, the cycle time of assembly can be greatly reduced. .

[0026] With reference to crimping mechanism 60 FIGS. 1 and 4, the crimping mechanism 60 forms a caulking punch 61 to the distal end, it is supported slidably in the axial direction and the support 29, by crimping advancing drive cylinder 62 A sleeve 63 and a swaging punch 61 slidably driven back and forth through the sleeve 63.
A piston 64 formed on the sleeve 63.

In the caulking advance / retreat drive cylinder 62, annular guide rods 75 (the guide rods 75 also serve as seal members) are inserted into both sides of the cylinder body 74, and annular guide rods 75 are provided at both ends of the cylinder body 74. This is a double shaft cylinder to which a side plate 76 is attached. Although not shown, oil passages for oil supply / discharge are appropriately formed in the left and right oil chambers 77, 78 of the piston 64, and the piston 64 is moved by the oil supply / oil discharge. Then, the caulking punch 61 is moved in the axial direction to perform the caulking operation.

The above-mentioned sleeve 63 is a first sleeve 7
1, a second sleeve 72 and a third sleeve 73. The second sleeve 72 and the third sleeve 73 are integrally connected via a pinion gear 66. The pinion gear 66 rotates integrally with the caulking punch 61 via the second sleeve 72. Further, a turning mechanism 65 for turning the caulking punch 61 at predetermined angles (for example, 45 degrees) in the circumferential direction thereof via the sleeve 63 of the caulking mechanism 60 is provided. The turning mechanism 65 includes the above-described pinion gear 66, a rack shaft 67 that meshes with the pinion gear 66, and a swage turning drive cylinder 68 that moves the rack shaft 67 back and forth in the axial direction. Reference numeral 69 denotes a case accommodating the rack shaft 67.

Control Unit Next, referring to FIG. 6, which is a schematic block diagram of a control system of the assembling apparatus, the control unit B includes the assembling units A and A '.
Control. Referring to the block diagram of FIG. 7 showing the relationship between the control unit B and one assembly unit A, the control unit B performs a sequence control of the CPU 91 which controls the control center and each drive cylinder in a predetermined order. Sequencer 92
And

The sequencer 92 has solenoid valves 94, 95, 96 for intermittently supplying oil to the chuck driving cylinder 93, the hook engaging / disengaging driving cylinder 42, the caulking advance / retreat driving cylinder 62, the caulking turning drive cylinder 68, and the clamp cylinder 90. , 97, 104,
By outputting a signal to each of the solenoid valves 94 to 97, 104, the chuck 110 (see FIG. 8) opens and closes the chuck 3 with respect to the coupled shaft 3, and engages and disengages the expanding hook 41 with the yoke 4. The control unit controls the forward / backward movement of the caulking punch 61, the turning operation of the caulking punch 61, and the locking operation of the stop position of the caulking unit 20, respectively.

The CPU 91 is connected to the sequencer 9
2 is connected to the sequencer 92 to exchange signals, and is connected to the proximity sensor 48 to input a signal from the proximity sensor 48. In addition, the CPU 91
ROM storing a program to be executed by the CPU 91
98 and a RAM 99 used as a work area of the CPU and the like.

Further, a position detector 84 provided on the caulking unit driving servomotor 81 is connected to the CPU 91, and a current detector 85 provided on the caulking unit driving servomotor 81 is connected to the A / D converter 86. Connected through. Similarly, a position detector 87 provided on the press-fit rod drive servomotor 52 is connected to the CPU 91, and a current detector 88 provided on the press-fit rod drive servomotor 52 is connected via an A / D converter 89. Connected. In addition, the CPU 91 includes each servo motor 8.
Drivers 101 and 102 as drive circuits for the servomotors 81 and 52 are connected to each other, and a signal is supplied from the CPU 91 to each driver to drive the servomotors 81 and 52. The CPU 91 detects the current of each of the servomotors 81 and 52, grasps the load based on the current, and stops the operation when the load reaches a predetermined level.

The CPU 91 controls the servo motors 81 and 52
Operation and the drive cylinders 94 to
The operation of each unit is comprehensively controlled by cooperating with the operation of 97. The sequencer 92 includes driving cylinders 94 to 94.
Various limiter switches related to the operation of the switch 97 are connected, but are not shown for simplicity. CPU 9
Reference numeral 1 designates a pair of assembly units A, A facing each other, and corresponding drive cylinders and servo motors are driven in synchronization with each other. The same applies to a pair of assembling units A 'and A' facing each other.

With respect to the expansion of the yoke by the hook and the press-fitting of the press-fitting rod, the hydraulic cylinders are conventionally synchronized with each other. In this case, however, there is a disadvantage that the tuning accuracy is poor. On the other hand, in the present embodiment, the expansion and press-fitting are tuned by the servo motors 81 and 52, respectively, so that the tuning accuracy is remarkably improved. Operation Referring to the timing chart shown in FIG. 10 and FIGS. 11A to 11F sequentially showing the assembling process, the operation of the assembling apparatus will be described with reference to the opposing cross shaft 1 corresponding to the pair of assembling units A. The description will be made in accordance with the case where the pair of shaft portions 2 is the reference side. (1) First, the pre-assembled cross joint is attached to the chuck 110 so that the axis of the cross shaft is vertical (as shown in FIG. 8). (2) Then, by pressing a push button switch (not shown), an automatic cycle of automatic assembly is started. (3) First, the caulking unit 20 of each of the assembly units A and A 'is moved to a position where the hook 41 reaches a position above the arm 5 which can be hooked on the arm 5 as shown in FIG. Moving forward [Timing (A) ~
(I)〕. (4) Then, as shown in FIG. 11 (b), each of the coupled shafts 3, 3 corresponding to the chucks 110, 1
10 at the same time [Timing (a) ~
(C)]. (5) Next, the hook engaging and disengaging mechanism 40 of each of the assembly units A and A 'hooks the hook 41 on the corresponding arm 5 of the yoke 4 as shown in FIG. 11C [timing (c) to (d)]. .

In each of the assembling units A and A ', the driving of the hook 41 starts at the same time as the timing (c).
When the press-fit rod 51 starts to advance and a predetermined load torque is obtained, that is, when a predetermined pressing force is generated, the advance is stopped [timing (e)]. The predetermined load torque is set relatively weak, and the cross shaft 1 is centered with respect to the assembling apparatus by the advance of the press-fit rod 41 from four directions. (6) In the assembling unit A for assembling the shaft part on the reference side, the caulking unit 20 is retracted simultaneously with the completion of the hooking of the hook 41 (at timing (d)). This is a so-called soft touch area in which the compression coil spring 47 is retracted from the timing (d) to the timing (f) while being bent. In this area, the hook 41 exerts a small pressing force on the inner end surface of the arm 5 due to the spring reaction force, but the arm 5 itself is not yet expanded.
As described above, the center position between the opposing arms is centered with respect to the present assembling apparatus through the definition of the position of the inner end face 5a of the arm 5 by the hook 41. On the other hand, since the cross axis 1 has already been centered in the above step 5), as shown in FIG.
And the center C2 between the arms 5 are centered.

In this state, the caulking unit 20 is temporarily stopped for a predetermined time [timing (f) to timing (g)], in order to confirm that the soft touch has been securely completed. After stopping, caulking unit 20
Is further retracted, and the caulking unit drive servo motor 8
1 at a timing (h) at which a predetermined load torque is obtained. That is, with reference to FIG. 11D, the yoke 4 is expanded by the hook 41 until a predetermined expanding stress is generated in the yoke 4, and the caulking unit 20 is stopped. The caulking unit 20 based on the force actually applied to the yoke 4
Is stopped, so that the expanded position of the hook 41 can be accurately set. (7) After this stop, in the assembly unit A, the rod 3 is moved by the hydraulic clamp cylinder 90 as a lock mechanism.
2 is clamped to lock the stop position of the caulking unit 20 (timing (h) to timing (h)). (8) At the same time as the end of this clamp,
In the assembly unit A, the press-fit rod 51 is advanced with relatively strong force to push the bottom 7a of the bearing case 7 as shown in FIG. Stop at the timing (k) at which torque is obtained. As a result, the bottom portion 7a of the bearing case 7 is brought into close contact with the end surface 2a of the shaft portion 2 of the cross shaft 1. Since the press-fit rod 51 is stopped based on the actual press-fit load, the advance position of the press-fit rod 51 can be set accurately. (9) Next, on the side of the assembly unit A ′, the same operations as those performed previously by the assembly unit A on the reference side are performed between the timings (d) and (c) in the above 6) to 8). Is performed between the timing (C) and the timing (S). (10) Next, in each of the assembly units A and A ′,
As shown in FIG. 11 (f), the caulking punch 61 is advanced, and as shown in FIG. 8, a part of the inner peripheral surface of the bearing hole 6 is raised and caulked on the outer peripheral edge of the bottom 7a of the bearing case 7. .
At this time, since the caulking punch advance / retreat driving cylinders 62 corresponding to the respective shaft portions 2 of the cross shaft 1 are simultaneously operated and caulked, the positional relationship between the already positioned cross shaft 1 and each arm 5 may be shifted. Absent.

The caulking punch 61 moves forward [time (S) to (T) and time (T) to (G)] and moves backward (Timing (H) to (T) a plurality of times with a predetermined stop time. ) And timing (c)-(m))
During stop time after returning (between timing (T) and (T))
Then, the caulking punch 61 is rotated in the circumferential direction by the caulking rotation drive cylinder 68, and the caulking position is made different at a plurality of locations in the circumferential direction. For example, by caulking two times by rotating the pair of caulking punches 61 at the circumferentially opposed positions by 45 degrees, caulking can be performed at four locations on the bottom 7a in the circumferential direction. The reason why the caulking is performed a plurality of times is to obtain a sufficient caulking load by using the small caulking punch advance / retreat drive cylinder 62. In addition, this is for preventing abnormal deformation of the yoke due to a large caulking force and for suppressing deterioration of the hook 41. (11) Next, in each of the assembly units A and A ', the retraction of the press-in rod 51 is started at the timing (c) at the same time as the start of the last reciprocation of the caulking punch 61, and the final reciprocation of the caulking punch 61 is started. At the same time as the end, the clamp is released at [timing (h)], and the lock of the stop position of the caulking unit 20 is released. (12) Next, in each of the assembly units A and A ', after the caulking unit 20 is advanced [at timing (f) to timing (f)], the hook 41 is moved from the yoke 4 at [timing (f) to timing (e). )]
After that, the caulking unit 20 is again turned on [timing (e)
At timing (M)], and the chucks of the coupled shafts 3 and 3 are released [at timing (M) to (M)], thereby completing one cycle and assembling the next work. Ready state.

In the present embodiment, since the expanding position of the hook 41 is defined based on the stress of the hook 41 at the time of expanding, the expanding torque of the yoke 4 can be kept constant regardless of the rigidity of the yoke 4. it can. Further, since the advance position of the press-fit rod 41 is determined based on the stress actually applied to the press-fit rod 41 at the time of press-fitting, the entire length of the shaft portion 2 of the cross shaft 1 and the thickness of the bottom portion 7a of the bearing case 7 vary. Also, the bottom portion 7a of the bearing case 7 can be securely brought into close contact with the end face of the shaft portion 2 of the cross shaft 1, and as a result, the arm center C2
(The center of the yoke) and the center C1 of the cross axis can be accurately matched.

In particular, since the extended position of the hook 41 and the advanced position of the press-fit rod 51 are defined in accordance with the load of the servomotors 81 and 52, the center C2 between the arms (the center of the yoke) and the center C1 of the cross shaft are defined. Can be more accurately matched. Further, in the related art, since the four shaft portions of the cross shaft were assembled at the same time, there was a possibility that the reference position of the cross shaft was not clear and the position was deviated. Since the remaining two shaft portions 2 (corresponding to the assembly unit A ′) are assembled after the assembly 2 (corresponding to the assembly unit A) is first performed, this does not occur. In the present embodiment, a part of the assembly process is shifted from each other. That is, in the assembly unit A, the steps (d) to (k) from the opening of the yoke to the press-fitting of the press-fit rod, and the corresponding timings (k) to (g) in the assembly unit A '.
Are shifted from each other. As described above, even if only a part of the assembling process is shifted, a sufficient effect can be obtained for preventing the reference position of the cross shaft from shifting. Although it is possible to shift all the assembling steps, it is preferable to perform the steps which can be performed at the same time, since the cycle time can be shortened.

The present invention is not limited to the above embodiments. For example, the hook 41 and the
A stress sensor is provided on an intermediate member (for example, the hook support 45, the T-shaped member 43, the ball screw 82, and other members) that receives a tensile load via the first member 1 to detect the tensile load, and based on the detected tensile load. Alternatively, the load of the caulking unit drive servomotor 81 may be detected. Further, a torque sensor for detecting the torque of the rotation transmitting member such as the ball screw 82 may be provided, and the load of the caulking unit driving servomotor 81 may be detected based on the detected torque.

A stress sensor is mounted on the press-fit rod 51 or an intermediate member (for example, the intermediate rods 53 and 54, the movable body 28, the ball screw 55, and other members) that receives a pressing load via the press-fit rod 51 when it is expanded. Alternatively, the pressing load may be detected, and the load of the press-fit rod driving servomotor 52 may be detected based on the detected pressing load. Further, a torque sensor for detecting the torque of the rotation transmitting member such as the ball screw 55 may be provided, and the load on the press-fit rod driving servomotor 52 may be detected based on the detected torque.

In addition, various design changes can be made within the scope of the present invention.

[0043]

According to the first aspect of the present invention, the expansion position of the hook is defined based on the stress of the hook at the time of expansion, so that the expansion torque of the yoke is kept constant regardless of the rigidity of the yoke. can do. Also, the rod advance position
Since it is determined based on the stress actually applied to the rod at the time of press fitting, even if the total length of the shaft of the cross shaft or the thickness of the bottom of the bearing case varies, the bottom of the bearing case must be securely connected to the shaft of the cross shaft. The center of the yoke and the center of the cross axis can be accurately matched with each other.

According to the second aspect of the present invention, the extended position of the hook and the extended position of the rod are defined in accordance with the load of the servomotor. Therefore, regardless of the rigidity of the yoke, the expansion torque of the yoke can be kept constant. Also, even if the overall length of the shaft of the cross shaft or the thickness of the bottom of the bearing case varies, the bottom of the bearing case can be securely brought into close contact with the end surface of the shaft of the cross shaft, and the center of the yoke and the cross shaft The center can be accurately matched.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an assembling unit of an assembling apparatus of a cross joint according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of the assembly unit of FIG.

FIG. 3 is a schematic plan view of the assembling apparatus.

FIG. 4 is a schematic sectional view of a front portion of the assembly unit.

FIGS. 5A and 5B are diagrams showing the operation of a hook expanding mechanism.

FIG. 6 is a block diagram showing a schematic configuration of the present assembling apparatus.

FIG. 7 is a block diagram showing a relationship between a control unit and one assembly unit.

FIG. 8 is a perspective view of the assembled cross shaft joint in a mounting posture of the assembly device.

FIG. 9 is a partial cross-sectional side view of a main part of the cross shaft joint in the caulking step.

FIG. 10 is a timing chart showing the operation of each part of the assembling apparatus.

FIGS. 11A to 11F are schematic diagrams sequentially showing an assembling operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cross shaft 2 Shaft part 3 Coupling shaft 4 Yoke 5 Arm 6 Bearing hole 7 Bearing case 8 Needle 10 Base 20 Caulking unit 40 Hook disengagement mechanism 41 Hook 50 Press-fit mechanism 51 Press-fit rod 52 Press-fit rod drive servomotor 60 Caulking mechanism 61 Caulking punch 62 Caulking forward / backward drive cylinder 65 Rotating mechanism 68 Caulking / rotating drive cylinder 81 Caulking unit drive servomotor 85,88 Current detector 86,89 A / D converter 90 Clamp cylinder B Control unit 91 CPU 92 Sequencer 98 ROM 99 RAM

Claims (2)

[Claims] A bottomed cylindrical bearing case for supporting each shaft portion of a cross shaft is disposed in a bearing hole of an opposite arm of a yoke of two coupled shafts. In a method of assembling a cross joint of a type in which a yoke expanding reaction force is exerted on an end face of a shaft portion, a stress applied to the hook when the yoke expanding hook is expanded at the expanding position of the yoke expanding hook A method of assembling a cross joint, wherein the position of the rod for press-fitting the bearing case into the bearing hole of the opposing arm of the yoke is specified based on the stress applied to the rod at the time of press-fitting. 2. A bottomed cylindrical bearing case for supporting each shaft portion of a cross shaft is disposed in a bearing hole of an opposing arm of a yoke of two coupled shafts. An assembly device for a cross joint, in which a reaction force of expanding the yoke is exerted on the end face of the shaft portion via the shaft, a servo motor for expanding the yoke to move the hook for expanding the yoke to the expanding position; Means for detecting the load applied to the expansion servomotor at the time of opening and controlling the expansion servomotor based on the load; a press-fit rod drive servomotor for advancing the rod for press-fitting the bearing case; Means for detecting a load applied to the press-fit rod drive servomotor and controlling the press-fit rod drive servomotor based on the load.