JP6331678B2 - Cross shaft type universal joint assembly method - Google Patents

Description

  The present invention relates to an improvement in a method for assembling a cruciform universal joint incorporated in a steering device for transmitting a motion of a steering shaft to a steering gear, for example.

  An automobile steering device is configured as shown in FIG. 3, for example. The movement of the steering wheel 1 is transmitted to the steering gear unit 4 via the steering shaft 2 and the intermediate shaft 3, and the wheels are steered by the steering gear unit 4. Generally, the steering shaft 2 and the input shaft 5 of the steering gear unit 4 cannot be provided on the same straight line. Therefore, conventionally, the intermediate shaft 3 is provided between the steering shaft 2 and the input shaft 5, and both ends of the intermediate shaft 3 and the ends of the steering shaft 2 and the input shaft 5 are connected. They are connected through universal joints 6 and 6 called cardan joints. Thereby, the rotational force can be transmitted between the steering shaft 2 and the input shaft 5 which do not exist on the same straight line.

  4-5 has shown what was described in patent document 1 as an example of the universal joint known conventionally. The universal joint 6 includes a pair of yokes 7 a and 7 b made of a metal plate and a cross shaft 8. Of the pair of yokes 7a and 7b, one yoke 7a (to the right in FIGS. 4 to 5) extends from the base 9a and one axial end edge (the left end edge in FIGS. 4 to 5) of the base 9a. A pair of connecting arm portions 10 and 10 are provided.

  Of these, the base portion 9a is inserted into an end portion of a rotating shaft (not shown) such as a steering shaft, so that the inner portion can be expanded and contracted by forming a circular cylinder with a discontinuous portion in one circumferential direction. In addition, a pair of flanges 11a and 11b facing each other are provided in the discontinuous portion. A through hole 12 for inserting a flange portion of a bolt (not shown) is formed in one of the flanges 11a. Along with this, a screw hole for screwing the bolt is provided by press-fitting and fixing a nut 14 to a through hole 13 formed in the other flange 11b.

  The connecting arm portions 10 and 10 extend in the axial direction of the base portion 9a from two positions opposite to the radial direction at one axial end portion of the base portion 9a. They are facing each other. In addition, concentric circular holes 15 and 15 are formed at the distal ends of the connecting arm portions 10 and 10, respectively.

  The other yoke 7b of the pair of yokes 7a and 7b (left side in FIGS. 4 to 5) differs from the one yoke 7a only in the shape of the base portion 9b. That is, the base 9b constituting the other yoke 7b is formed in a substantially cylindrical shape as a whole in order to insert the end of the rotary shaft 16 such as an intermediate shaft.

  The cross shaft 8 has two shaft portions 17a and 17b provided so as to intersect with the cross constituting the cross shaft 8, and both ends of one shaft portion 17a are connected to the connecting arm of the one yoke 7a. The circular holes 15 and 15 are pivotally supported inside the circular holes 15 and 15 formed in the portions 10 and 10 and the both end portions of the other shaft portion 17b are also formed in the coupling arm portions 10 and 10 of the other yoke 7b. 15 is pivoted inside. For this purpose, the end portions of the shaft portions 17a and 17b constituting the cross shaft 8 are rotatably supported inside the circular holes 15 and 15 via cup bearings 18 respectively.

  Each cup bearing 18 corresponds to a shell type needle bearing, and includes one cup 19 corresponding to a shell type outer ring and a plurality of needles 20 and 20. Of these, the cup 19 is formed by bending a hard metal plate such as a carbon steel plate or a case-hardened steel plate by plastic working such as deep drawing, and includes a cylindrical portion 21, a bottom portion 22, an inward flange portion 23, and the like. Is provided. Of these, the bottom portion 22 closes the whole axial one end side of the cylindrical portion 21 (the outer surface side of the connecting arm portion 10 in the assembled state in the circular hole 15). Further, the inward flange 23 is bent radially inward from the other axial end of the cylindrical portion 21 (in the assembled state in the circular hole 15, the inner side of the coupling arm portion 10). The surface facing each of the needles 20 and 20 is curved in a direction that becomes a concave surface. The cups 19 and 19 having the above-described configuration are press-fitted inside the circular holes 15 and 15, and the circular holes 15 are formed on the outer surfaces of the coupling arm portions 10 and 10. , 15 are plastically deformed radially inward to form caulking portions 24, 24, thereby preventing the cups 19, 19 from slipping out of the circular holes 15, 15. . Further, the distal end portions of the shaft portions 17a and 17b constituting the cross shaft 8 are respectively inserted inside the needles 20 and 20 in the radial direction.

  When the universal joint 6 configured as described above is used, as shown in FIGS. 4 to 5, the end of the rotary shaft 16 is inserted or pressed into the base 9 b constituting the other yoke 7 b without rattling. In this state, the base 9b and the end of the rotary shaft 16 are welded and fixed. At the same time, the flange portion is inserted into the through-hole 12 formed in one flange 11a in a state where the end portion of another rotating shaft 25 is spline-engaged inside the base portion 9a constituting the one yoke 7a. The tip of a bolt (not shown) is screwed into a nut 14 fixed to the other flange 11b and tightened. Thus, the end of the other rotary shaft 25 is coupled and fixed to the base portion 9a based on reducing the diameter of the base portion 9a by narrowing the distance between the flanges 11a and 11b. And, by connecting the ends of the two rotary shafts 16 and 25 via the universal joint 6 in this way, between the rotary shafts 16 and 25 that do not exist on the same straight line, Enable to transmit rotational force.

  Next, a method for assembling the universal joint 6 having the above-described configuration will be described. FIG. 6 shows an example of a conventionally known assembly method. In the case of the illustrated example, the yoke receiving jig 26 is configured in a state in which both ends of the shaft portion 17a constituting the cross shaft 8 are loosely inserted inside the pair of circular holes 15 constituting the yoke 7a. The tip portions of the L-shaped pair of support arm portions 27 are arranged inside the pair of coupling arm portions 10. Further, press-fitting punches 28 and caulking punches 29 are arranged coaxially with the respective circular holes 15 at both side positions sandwiching both the connecting arm portions 10. Of these, the press-fitting punch 28 is formed in a columnar shape, and can be moved in the front-rear direction (left-right direction in FIG. 6) by a press-fitting cylinder (not shown) provided on the base end side. On the other hand, the caulking punch 29 is formed in a substantially cylindrical shape and is fitted around the press-fitting punch 28. The caulking punch 29 can be moved in the front-rear direction (left-right direction in FIG. 6) by a caulking cylinder (not shown) provided on the base end side.

  In the case of the conventional method, first, by driving a motor (not shown) constituting the yoke receiving jig 26, the both supporting arm portions 27 are moved in synchronization with each other in the direction away from the machine center position. Then, the outer surfaces of the distal ends of the two supporting arm portions 27 are brought into contact with the inner side surfaces of the distal ends of the two connecting arm portions 10 to support the both connecting arm portions 10. Thereafter, the both press-fitting punches 28 are respectively moved forward (moved in a direction approaching the yoke 7a) to press the inner surface of the bottom portion 22 constituting the cup bearing 18 against the tip surface of the shaft portion 17a. When the amount of forward movement 28 reaches a predetermined amount, the forward movement is stopped. Next, both the caulking punches 29 are moved forward to plastically deform a plurality of portions of the opening edge portions of the circular holes 15 in the both connecting arm portions 10, and the caulking portions 24, 24 are applied to the portions. Form. As a result, the cup bearing 18 is assembled to a portion between the circular holes 15 and both end portions of the shaft portion 17a, and both end portions of the shaft portion 17a are inside the circular holes 15 and the cup bearing 18 is assembled. It is supported rotatably via

However, in the case of the assembling method as described above, the press-fitting amount (press-fitting position) of the cup bearing 18 is determined based only on the amount of forward movement of the press-fitting punch 28. It can happen. Hereinafter, FIG. 7 will be described in addition to FIG.
The dimension from the central axis of the yoke 7a (7b) to the inner surface of the pair of connecting arm portions 10 and 10 (hereinafter referred to as “inner surface dimension”) always varies within a dimensional tolerance. Therefore, when the support arms 27 and 27 are moved by an equal distance in the direction away from the machine center position O to support the yoke 7a (7b), the yoke 7a (7b) In accordance with variations in the inner surface dimensions of the connecting arm portions 10 and 10, the center holes of the circular holes 15 and 15 are displaced in the direction of the central axis (the left-right direction in FIG. 7). Specifically, as shown in FIG. 7A, the center position X of the yoke 7a (7b) is made to coincide with the machine center position O of the both support arm portions 27, 27, and One of the support arm portions 27, 27 (on the right side in FIG. 7) from the outer surface of the tip end portion of the support arm portion 27, one of the coupling arm portions 10, 10 (on the right side in FIG. 7). The distance (L1) to the inner surface of the distal end of the coupling arm 10 and the coupling arm of the other (left side of FIG. 7) from the outer surface of the distal end of the other supporting arm 27 (left side of FIG. 7). When the distance (L2) to the inner surface of the tip 10 is not equal (L1 <L2), as shown in FIG. The yoke 7a (7b) is displaced in the direction of the central axis of the circular holes 15 and 15 (right side in the figure). For this reason, the center position X of the yoke 7a (7b) in a state where the support is completed is shifted by ΔA with respect to the machine center position O of the both support arm portions 27 and 27.

  On the other hand, since the amount of forward movement of both the press-fit punches 28, 28 is set with reference to the machine center position O, one of the press-fit punches 28, 28 (the right side in FIG. 7). While the press-fitting amount by 28 is excessive, the press-fitting amount by the other press-fitting punch 28 (to the left in FIG. 7) is insufficient. Accordingly, it is difficult to stably apply an appropriate preload to the pair of cup bearings 18 and 18. For the same reason, the caulking amount of one (right side in FIG. 7) of the both caulking punches 29 and 29 is excessive, while the other (left side in FIG. 7) is caulked. The amount of caulking by the punch 29 is insufficient. Therefore, there is a possibility that at least one cup bearing 18 cannot be sufficiently prevented from coming off.

JP-A-10-205547

  In view of the circumstances as described above, the present invention provides a circular hole that constitutes a yoke and an end portion of a shaft that constitutes a cross shaft, regardless of variations in the inner surface dimensions of a pair of connecting arm portions that constitute the yoke. Invented in order to realize a method for assembling a cruciform universal joint in which a cup bearing can be assembled with high accuracy between the two.

  The method of assembling the cross shaft universal joint according to the present invention includes a pair of circular holes formed concentrically at the tips of a pair of connecting arm portions constituting a yoke, and both of these couplings inside these circular holes. In order to incorporate a pair of cup bearings into the portion between both ends of the shaft portion of the cross shaft inserted from the inner side surface of the arm portion, the inner side surfaces of the tip end portions of the coupling arm portions are supported by a pair of support members. In a method of assembling a cross shaft type universal joint, the cup bearings are press-fitted with a pair of press-fitting punches into the inner sides of the circular holes from the outer surface side of the coupling arm portions in a state of being supported (backed up). is there.

In particular, in the case of the present invention, first, the two supporting members are moved toward each other so as to approach the inner side surfaces of the connecting arm portions in a direction parallel to the central axis of the circular holes based on driving of the servo motors. Move it away. Then, when predetermined torques equal to each other set in advance are generated in the two servo motors, the movement of the two support members is stopped, and the inner side surfaces of the front ends of the coupling arm portions are supported by the two support members.
Thereafter, using the number of pulses of the two servo motors, the two supporting members are supported in a state in which both the connecting arm portions are supported from the machine center position of the both supporting members (the center position in the central axis direction of the circular hole). The amount of deviation to the center position is obtained, and the amount of forward movement of the two press-fitting punches is corrected based on this amount of deviation.

  When carrying out the method of assembling the cruciform universal joint of the present invention, for example, as in the invention described in claim 2, after the both cup bearings are press-fitted inside the circular holes by the both press-fitting punches, Using a pair of caulking punches, a step of plastically deforming the opening edge portions of the circular holes in the outer surfaces of the supporting arm portions is provided. Then, the amount of forward movement of the both caulking punches is corrected based on the amount of deviation.

According to the method of assembling the cross shaft type universal joint of the present invention configured as described above, the circular hole and the cross constituting the yoke are formed regardless of variations in the inner surface dimensions of the pair of connecting arm portions constituting the yoke. The cup bearing can be assembled with high accuracy in the portion between the tip portion of the shaft portion constituting the shaft.
That is, in the case of the present invention, the pair of support members that support the inner surfaces of the pair of coupling arms are moved away from each other by driving the servo motors, and the two servo motors are moved to a predetermined distance. When the torque is generated, the movement is stopped and the support of both the connecting arm portions is completed. Then, using the number of pulses of the two servo motors, the amount of deviation from the machine center position of the two support members to the center position of the two support members in a state where the two coupling arm portions are supported is obtained. Based on the amount, the amount of forward movement of the both press-fitting punches is corrected. Therefore, according to the present invention, it is possible to eliminate the influence of the variation in the inner side surface dimensions of the both connecting arm portions on the forward movement amount of the both press-fitting punches. As a result, according to the present invention, the cup bearing can be accurately assembled at an appropriate position where an appropriate preload can be applied, regardless of variations in the inner side surface dimensions of both the connecting arm portions.

  According to the second aspect of the present invention, it is possible to eliminate the influence of the variation in the inner side surface dimensions of the coupling arm portions on the amount of forward movement of the pair of caulking punches. For this reason, it is possible to prevent the caulking amount (plastic deformation amount) from being insufficient, and to sufficiently prevent the cup bearing from coming off.

The fragmentary sectional view which shows the assembly method of a universal joint which shows the 1st example of embodiment of this invention in process order. The figure similar to FIG. 1 which shows a 2nd example similarly. The perspective view which shows an example of the steering device incorporating a universal joint. The side view which shows an example of the universal joint known conventionally. The figure seen from the lower part of FIG. 4 shown in the state which cut | disconnected a part. It is a fragmentary sectional view which shows the assembly method of the universal joint conventionally known, (A) has shown the press injection process, (B) has shown the crimping process. The fragmentary sectional view shown in order to demonstrate the problem by the assembly method known conventionally.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention. The feature of this example is that by devising the backup process (support process) of the yoke 7a, the inner surface dimensions (from the yoke central axis to the inner surface) of the pair of connecting arm portions 10 and 10 constituting the yoke 7a. The cup bearing 18 can be assembled with high accuracy regardless of variations in the distance). Since the structure and operational effects of the universal joint 6 that is the object of the assembly method of this example are the same as those of the above-described conventional structure, illustration and description regarding equivalent parts are omitted, and the features of this example are described below. The assembly method which is a part will be mainly described.

  The method of assembling the universal joint 6 of this example is roughly divided into four steps (A) to (D). Each of these steps will be described below in the order of steps. FIG. 1 shows only a yoke receiving jig 31 and a pair of press-fitting caulking devices 32 and 32, which are main devices among the assembling devices 30 used in the assembling method of this example.

[(A) Preliminary process]
As shown in FIG. 1A, circular holes 15 and 15 formed in a pair of connecting arm portions 10 and 10 constituting a yoke 7a are connected to both end portions of one shaft portion 17a constituting the cross shaft 8. The yoke 7a is held downward by a chuck (not shown) at a position above the yoke receiving jig 31 in a pre-assembled state inserted into each of them. More specifically, with respect to the central axis direction of the circular holes 15 and 15 (left and right direction in FIG. 1), the machine center position O of the yoke receiving jig 31 (assembly device 30) and the center position of the yoke 7a ( The yoke 7 a is disposed above the yoke receiving jig 31 in a state where it is aligned with the central axis (X). Further, both end portions of the one shaft portion 17a are positioned at the centers of the circular holes 15 and 15 by using a centering jig (not shown).

  Next, the yoke 7a is lowered by a predetermined amount to constitute the circular holes 15 and 15 formed at the distal ends of the coupling arm portions 10 and 10, and the press-fitting caulking devices 32 and 32, respectively. A pair of cylindrical press-fitting punches 33, 33 (and caulking punches 34, 34) are positioned coaxially. Further, in this state, a pair of support arm portions 35, 35 configured in a substantially L shape, constituting the yoke receiving jig 31, between the inner side surfaces of the tip end portions of the both connecting arm portions 10, 10. Insert the tip. In the case of this example, both the supporting arm portions 35 and 35 are driven by separate servo motors 36 and 36, respectively, so that they can move in the direction parallel to the central axis of the circular holes 15 and 15. Yes. Further, the movement (opening / closing operation) of the support arm portions 35, 35 is controlled by controlling the torque of the servo motors 36, 36. The support arm portions 35 and 35 correspond to a pair of support members described in the claims.

[(B) Backup process]
Next, both the servo motors 36 and 36 are driven to move the both support arm portions 35 and 35 away from the machine center position O. The side surface is brought into contact with the inner side surface of the distal end portion of both the connecting arm portions 10 and 10. Further, in the case of this example, the movement speed, the movement start timing, and the like are shifted so that the operations of the support arm portions 35 and 35 do not completely coincide (synchronize). The two supporting motors 36 and 36 are supported until a predetermined torque equal to each other (a torque capable of providing a pressing force enough to back up the pair of coupling arm portions 10 and 10) is generated. The arm portions 35 and 35 are moved (separated). In the case of this example, during execution of the backup process, the yoke 7a is held by the chuck so that at least the movement of the circular holes 15, 15 in the direction of the central axis (parallel movement) is possible, or the both When the support by the support arm portions 35, 35 is started, the holding of the yoke 7a by the chuck is released. As a result, as shown in FIG. 1B, the yoke 7a is displaced in the direction of the central axis of the circular holes 15 and 15 (translational movement) as the support arm portions 35 and 35 move. To do). In addition, in this deviation | shift amount, the deviation | shift part resulting from the dispersion | variation in the inner surface dimension of the said both connecting arm parts 10 and 10 is included. Then, when a predetermined torque equal to each other set in advance is generated in both the servo motors 36, 36, the movement of the both support arm portions 35, 35 is stopped, and the both support arm portions 35, 35 are used to The inner side surfaces of the distal ends of the coupling arm portions 10 and 10 are supported.

  Thus, when the backup process of this example is completed, the center position (the center position between the outer surfaces of the tip end portions) P of the support arm portions 35 and 35 is obtained. In the case of this example, both the support arm portions 35, 35 are driven by the servo motors 36, 36, respectively. By calculating the respective feed amounts (movement amounts from the machine center position O) of the support arm portions 35, 35 using the number of pulses of the servo motors 36, 36, the support arm portions 35, 35 A center position P is obtained. Then, when the center position P of both the support arm portions 35, 35 is obtained in this way, the deviation amount (Δα) of the center position P from the machine center position O is obtained. Prior to the press-fitting process described later, a pair of cup bearings 18 and 18 are supplied coaxially with the circular holes 15 and 15 and the press-fitting punches 33 and 33 using a bearing supply device (not shown). . These two cup bearings 18 and 18 can be supplied at the stage of the preliminary process and stand by as shown in FIG.

[(C) Press-in process]
Next, by driving the servo motors constituting the both press-fitting caulking devices 32, 32, the both press-fitting punches 33, 33 are moved forward (moved toward each other), respectively, and both the cup bearings 18, 18 is simultaneously press-fitted into the circular holes 15 and 15 from the outer surface side of the connecting arm portions 10 and 10. Particularly in the case of this example, the feed amount (forward movement amount) of both the press-fitting punches 33, 33 is corrected according to the deviation amount (Δα) obtained as described above. Specifically, in the case of the illustrated example, since the center position P of both the support arm portions 35 and 35 is shifted to the right side by Δα from the machine center position O, the front end surface of the left press-fitting punch 33 is The press-fitting command position (the press-fitting completion position set on the assumption that no deviation has occurred) Y1 is set so as to move to a position (corrected press-fitting command position Y1 ′) to which Δα is added. The tip end surface 33 is set so as to move from the normal press-fitting command position Y2 to a position (corrected press-fitting command position Y2 ′) minus Δα. Then, both the press-fitting punches 33, 33 are moved to the set correction press-fitting command positions (Y1 ′, Y2 ′), respectively, and the press-fitting operation is completed. With the both press-fitting punches 33, 33 moved to such a corrected press-fitting command position, the inner surfaces of the bottom portions 22, 22 of the both cup bearings 18, 18 are in contact with the front end surface of the shaft portion 17a. After that, a predetermined amount is press-fitted and pre-load is applied.

[(D) Caulking step]
Next, by driving a servo motor (servo motor different from the servo motor used for driving the press-fitting punch 33) constituting the both press-fitting caulking devices 32, 32, or a cylinder operated by hydraulic pressure or pneumatic pressure is driven. By doing so, the pair of caulking punches 34, 34 are moved forward. In particular, in the case of this example, as in the case of the press-fitting process described above, the feed amount (the amount of forward movement) of both the caulking punches 34, 34 is set to the deviation amount (Δα) obtained as described above. Corrections are made accordingly. Specifically, in the case of the illustrated example, the center position P of the support arm portions 35, 35 at the time when the backup process is completed is shifted to the right side from the machine center position O by Δα. The position of the front end surface of the caulking punch 34 is moved to a position (corrected caulking command position Z1 ′) obtained by adding Δα to a normal caulking command position (caulking completion position set on the assumption that no deviation occurs) Z1. On the contrary, the position of the front end surface of the right caulking punch 34 is set to be moved to a position (corrected caulking command position Z2 ′) obtained by subtracting Δα from the normal caulking command Z2. Then, the front end surfaces of the both caulking punches 34, 34 are moved to the respective corrected caulking command positions (Z1 ′, Z2 ′), and the two circular holes are formed by the front end surfaces of the both caulking punches 34, 34. A plurality of portions in the circumferential direction of the inner peripheral edge portions 15 and 15 are plastically deformed. And the caulking parts 24 and 24 (refer FIGS. 4-6) are formed in the said part. As a result, the caulking portions 24, 24 are pressed against the outer surfaces of the bottom portions 22, 22 constituting the cups 19, 19, thereby preventing the cups 19, 19 from coming out of the circular holes 15, 15. To do.
In the case of this example as well, like the caulking punch used in the conventional method shown in FIG. 6, cylindrical caulking punches 34, 34 are used, and these caulking punches 34, 34 are used. Are arranged around the two press-fitting punches 33, 33 in a state of being externally fitted.

  Finally, both the caulking punches 34 and 34 and the both press-fitting punches 33 and 33 are retracted to their initial positions. Further, the support arm portions 35, 35 constituting the yoke receiving jig 31 are moved in a direction approaching each other, and the backup of the combined arm portions 10, 10 by the support arm portions 35, 35 is performed. To release. Next, the yoke 7 a is moved (retracted) to a position above the yoke receiving jig 31, and the yoke 7 a is taken out from the assembly apparatus 30.

According to the assembling method of the present example having the steps as described above, the circular holes 15 constituting the yoke 7a, regardless of variations in the inner surface dimensions of the pair of connecting arm portions 10 and 10 constituting the yoke 7a, The pair of cup bearings 18 and 18 can be assembled with high accuracy between the portion 15 and both ends of the shaft portion 17a constituting the cross shaft 8.
That is, in the case of this example, both the supporting arm portions 35 and 35 that support the inner surfaces of the both connecting arm portions 10 and 10 are moved away from each other by driving the servo motors 36 and 36, respectively. When the predetermined torque is generated in both the servo motors 36, 36, the movement is stopped, and the support of the both connecting arm portions 10, 10 is completed. Then, by using the number of pulses of both the servo motors 36, 36, the both support arms 10 and 10 are supported from the machine center position O of the both support arms 35, 35. Deviation amounts (Δα) of the portions 35 and 35 to the center position P are obtained, and based on the deviation amounts, the forward movement amounts of the press-fitting punches 33 and 33 and the caulking punches 34 and 34 are respectively corrected. ing. For this reason, in the case of this example, the variation in the inner side surface dimensions of the connecting arm portions 10 and 10 has an influence on the forward movement amounts of the press-fitting punches 33 and 33 and the caulking punches 34 and 34. Can be eliminated. Therefore, according to the assembling method of this example, the cup bearings 18 and 18 can be assembled with high accuracy at an appropriate position where an appropriate preload can be applied, regardless of variations in the inner surface dimensions of the connecting arm portions 10 and 10. In addition, the caulking amount (plastic deformation amount) of the caulking portions 24, 24 can be prevented from being insufficient, and the cup bearings 18, 18 can be sufficiently prevented from coming off. As a result, according to the assembling method of the present example, the both cup bearings 18 and 18 can be assembled with high accuracy regardless of variations in the inner surface dimensions of the both connecting arm portions 10 and 10.

In the case of this example, in order to support both the connecting arm portions 10 and 10 by moving the both supporting arm portions 35 and 35 until a predetermined torque is generated in both the servo motors 36 and 36, regardless of the variation of the inner surface dimensions of these two coupling arms 10 and 10, it is possible to support both of these coupling arms 10, 10 at a proper force.

[Second Example of Embodiment]
FIG. 2 shows a second example of the embodiment of the present invention. The feature of this example is that the variation in the axial dimension of the shaft portion 17a constituting the cross shaft 8 and the variation in the thickness dimension of the bottom portion 22 of the cup 19 constituting the cup bearing 18 are the press-fitting punches 33, 33. In addition, the influence on the amount of forward movement of the caulking punches 34, 34 is eliminated. Since the other steps are the same as in the case of the first example of the above-described embodiment, the overlapping description will be omitted or simplified, and the following description will focus on the press-fitting step and the caulking step, which are characteristic portions of this example. Explained.

In the case of this example, as shown in FIG. 2A, the yoke 7a is set in the assembling apparatus 30a by the preliminary process as shown in FIG. Perform a backup process. Even in the backup process, as in the case of the first example of the embodiment, by driving the servo motors 36, 36, a pair of support arm portions 35, 35 constituting the yoke receiving jig 31 is provided. Are driven in directions away from each other (left and right in FIG. 2). Then, when a predetermined torque equal to each other set in advance is generated in both the servo motors 36, 36, the movement of the both support arm portions 35, 35 is stopped, and the both support arm portions 35, 35 are used to The inner side surfaces of the distal ends of the coupling arm portions 10 and 10 are supported. Further, the shift amount (Δα) from the machine center position O of both the support arm portions 35 and 35 to the center position P of the both support arm portions 35 and 35 in a state where the both joint arm portions 10 and 10 are supported. Ask for. The steps up to here are the same as those in the assembly method of the first example. The feature of this example is in the following press-fitting process and caulking process.

  Also in the case of this example, as shown in FIG. 2C, by driving the servo motors constituting the press-fitting caulking devices 32a, 32a, the press-fitting punches 33, 33 are respectively moved forward, The cup bearings 18 and 18 are simultaneously press-fitted into the circular holes 15 and 15 from the outer surface side of the coupling arm portions 10 and 10. In addition, the feeding amounts of the press-fitting punches 33 and 33 are determined in the above-described manner while the both connecting arm portions 10 and 10 are supported from the machine center position O of the both supporting arm portions 35 and 35. The correction is made in accordance with the amount of deviation (Δα) of the both support arm portions 35, 35 up to the center position P. Specifically, in the case of the illustrated example, since the center position P of both the support arm portions 35 and 35 is shifted to the right side by Δα from the machine center position O, the front end surface of the left press-fitting punch 33 is It is set to move to the position where Δα is added to the press-fitting command position Y1 (corrected press-fitting command position Y1 ′), and conversely, the tip surface of the right press-fitting punch 33 is a position obtained by subtracting Δα from the normal press-fitting command position Y2. It is set to move to (correction press-fitting command position Y2 ′).

  Furthermore, in the case of this example, the magnitude of the pressure (pressing reaction force) applied to both the press-fitting punches 33, 33 is measured by pressure sensors installed on the both press-fitting punches 33, 33, respectively. In this way, the reason for measuring the pressure applied to both the press-fitting punches 33, 33 is that the axial dimension of the shaft portion 17a constituting the cross shaft 8 and the thickness dimension of the bottom portion 22 constituting the cup 19 are as follows. Since the dimensions always vary within the dimensional tolerance, before the both press-fitting punches 33, 33 reach the corrected press-fitting command position (Y1 ′, Y2 ′), the appropriate preload is applied to the cup bearings 18, 18. Or even when the corrected press-fitting command position (Y1 ′, Y2 ′) is reached, there is a possibility that an appropriate preload is not applied to the cup bearings 18, 18 (the preload is insufficient). It is. For this reason, in the case of this example, even if the feed amount of the both press-fitting punches 33, 33 does not reach the corrected press-fitting command position (Y1 ′, Y2 ′), they are applied to the both press-fitting punches 33, 33. The press-fitting operation is finished when the pressure value reaches a predetermined value. Then, a difference (−Δβ) between the position where the press-fitting by both the press-fitting punches 33, 33 is actually completed and the corrected press-fitting command position (Y1 ′, Y2 ′) is obtained. On the contrary, even if the feed amount of the both press-fitting punches 33, 33 has reached the corrected press-fitting command position (Y1 ′, Y2 ′), the value of the pressure applied to both the press-fitting punches 33, 33 becomes the predetermined value. If not reached, the forward movement is continued, and the press-fitting operation is terminated when the predetermined value is reached. Also in this case, the difference (+ Δβ) between the position where the press-fitting by both the press-fitting punches 33, 33 is actually completed and the corrected press-fitting command position (Y1 ′, Y2 ′) is obtained.

  In the subsequent caulking step, the feed amounts of the two caulking punches 34 and 34 are corrected according to the two shift amounts of Δα and Δβ. Specifically, in the case of the illustrated example, since the center position P of the both support arm portions 35, 35 is shifted to the right side by Δα from the machine center position O, the position of the front end surface of the caulking punch 34 on the left side is determined. Set to move to the first correction caulking command position (Z1 ′) obtained by adding Δα to the normal caulking command position Z1 to the position (second correction caulking command position Z1 ′ ± Δβ) further increased or decreased by Δβ. In addition, the position of the front end surface of the right caulking punch 34 is a position (second correction caulking command position Z2) obtained by adding or subtracting Δβ to the first correction caulking command position (Z2 ′) obtained by subtracting Δα from the normal caulking command position Z2. It is set to move to '± Δβ). Then, the front end surfaces of the two caulking punches 34, 34 are moved to the respectively set second correction caulking command positions (Z1 ′ ± Δβ, Z2 ′ ± Δβ), respectively. As a result, a plurality of locations in the circumferential direction of the inner peripheral edge portions of the circular holes 15 and 15 are plastically deformed. And the caulking parts 24 and 24 (refer FIGS. 4-6) are formed in the said part. As a result, the caulking portions 24, 24 are pressed against the outer surfaces of the bottom portions 22, 22 constituting the cups 19, 19, thereby preventing the cups 19, 19 from coming out of the circular holes 15, 15. To do.

In the case of this example having the above-described configuration, the axial dimension of the shaft part 17a of the cross shaft 8 and the variation in the thickness dimension of the bottom part 22 constituting the cup 19 are different from each other. 33 and the amount of forward movement of the two caulking punches 34, 34 can be eliminated. For this reason, in the case of this example, both the cup bearings 18, 18 are not affected by variations in the axial dimension of the shaft portion 17 a of the cross shaft 8 and the thickness dimension of the bottom portion 22 constituting the cup 19. An appropriate preload can be applied, and the amount of caulking of the caulking portions 24, 24 can be made appropriate (ensure sufficiently). Therefore, both the cup bearings 18 and 18 can be assembled with high accuracy.
Other processes and effects are the same as in the first example of the above embodiment.

  The cross shaft type universal joint which is an object of the assembling method of the present invention is not limited to the steering device, and can be used in a state assembled to a propeller shaft and various torque transmission mechanisms.

  When carrying out the present invention, the pair of support members constituting the yoke receiving jig do not necessarily need to move both support members. That is, one support member of the pair of support members may be fixed and only the other support member may be moved, and both the support members may be configured so as to be movable in the distance.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Intermediate shaft 4 Steering gear unit 5 Input shaft 6 Universal joint 7a, 7b Yoke 8 Cross shaft 9a, 9b Base part 10 Coupling arm part 11a, 11b Flange 12 Through hole 13 Through hole 14 Nut 15 Circular hole 16 Rotating shafts 17a and 17b Shaft portion 18 Cup bearing 19 Cup 20 Needle 21 Cylindrical portion 22 Bottom portion 23 Inward flange portion 24 Caulking portion 25 Rotating shaft 26 Yoke receiving jig 27 Support arm portion 28 Press-fit punch 29 Caulking punch 30, 30a Assembly device 31 Yoke receiving jig 32, 32a Press fitting caulking device 33 Press fitting punch 34 Caulking punch 35 Support arm portion 36 Servo motor

Claims (2)

A pair of circular holes formed concentrically with each other at the front ends of a pair of coupling arm portions constituting the yoke, and a cross shaft inserted from the inner surface side of both the coupling arm portions inside these circular holes. In order to incorporate a pair of cup bearings in a portion between both ends of the shaft portion, the both cup bearings are connected to the both circles in a state where the inner side surfaces of the front ends of the coupling arm portions are supported by a pair of support members. A method of assembling a cruciform universal joint, wherein a pair of press-fitting punches are press-fitted into the inside of a hole from the outer surface side of both the connecting arm portions,
The both support members are moved in directions away from each other so as to approach the inner side surfaces of the two connecting arm portions in a direction parallel to the center axis of the two circular holes based on driving of the servo motors, respectively. When a predetermined torque is generated in the motor, the movement of both the supporting members is stopped, and the inner side surfaces of the front ends of the coupling arm portions are supported by the both supporting members.
Using the number of pulses of the two servo motors, obtain the amount of deviation from the machine center position of the two support members to the center position of the two support members in the state where the two coupling arm portions are supported,
An assembly method of a cross shaft type universal joint, wherein the amount of forward movement of each of the press-fitting punches is corrected based on the amount of deviation. After the cup bearings are press-fitted inside the circular holes by the press-fitting punches, an opening edge portion of the circular holes is formed on the outer surfaces of the coupling arm portions using a pair of caulking punches. A step of plastically deforming, and respectively correcting the amount of forward movement of the two crimping punches based on the amount of deviation,
A method of assembling the cross shaft type universal joint according to claim 1.

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