JPH0335035B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a positioning jig for a cylindrical workpiece to be welded to a main body.

Generally, when welding a cylindrical workpiece to a main body, for example, as shown in FIG. Examples include things that are welded. In this case, a pair of king pin bosses 2 are generally welded to the upper and lower parts of both ends of the axle center 1, and a king pin 3 is fitted into the king pin boss 2, and a wheel 5 is connected to the king pin 3 via a spindle 4.
The king pin boss 2 functions as a bearing for the king pin 3. Therefore, when welding the king pin boss 2 to the axle center 1, the king pin boss 2 must be positioned with respect to the axle center 1, which has been positioned in advance, in order to set the axis of the king pin 3 at a predetermined position. It didn't happen.

Therefore, conventionally, as shown in FIGS. 2 to 4, a positioning jig J is used to position the above-mentioned king pin boss 2.
This positioning jig J was attached to the positioning jig 6 of the axle center 1, for example. That is, the axle center 1 positioning jig 6 has a block 8 installed at a desired location on the base plate 7, and the axle center 1 is placed on this block 8 to position the axle center 1 with respect to the base plate 7. I'm starting to do that. On the other hand, the positioning jig J for the king pin boss 2 is provided on the base plate 7 corresponding to both ends of the positioning position of the axle center 1, and is a support base fixed to the base plate 7 and provided with a horizontal support surface 9a. 9, and a positioning shaft 10 which has a male threaded portion 10a screwed into the female threaded portion 9b of the support 9 and is erected on the support 9. Then, a pair of upper and lower king pin bosses 2 are fitted into the positioning shaft 10, thereby positioning the axis of the king pin boss 2. In this case, the lower kingpin boss 2 is positioned in the vertical direction because its lower surface abuts the support surface of the support base 9, and the upper kingpin boss 2 has a collar between it and the lower kingpin boss 2. 1
1, the position is determined in the vertical direction. When the axle center 1 and king pin boss 2 are positioned in this way,
Both are welded (arc welded) using a welding device not shown.

In such a conventional positioning jig for a cylindrical workpiece, the kingpin boss 2 as a cylindrical workpiece is fitted into one positioning shaft 10 to position the axis of the kingpin boss 2. Therefore, it is necessary to ensure a clearance C between the inner diameter of the king pin boss 2 and the outer diameter of the positioning shaft 10, and this clearance C
had to be set small. However, when welding the king pin boss 2, the king pin boss 2 is distorted and deformed by the welding heat, so if the clearance C is set too small, the thermally distorted portion of the king pin boss 2 will come into pressure contact with the peripheral wall of the positioning shaft 10. After welding, the king pin boss 2 is removed from the positioning shaft 10.
This may result in a situation where it is impossible to leave. For this reason,
It is necessary to set the above-mentioned clearance C to a certain extent, and as a result, the king pin boss 2 shakes against the positioning shaft 10, and the axis of the king pin boss 2 shifts from the axis of the positioning shaft 10. Kingpin Boss 2
The positioning accuracy becomes low.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to improve the positioning accuracy of a cylindrical workpiece, and to improve the positioning accuracy of a cylindrical workpiece without being affected by thermal distortion during welding. It is an object of the present invention to provide a positioning jig for a cylindrical workpiece that enables subsequent removal of the cylindrical workpiece.

The gist of the present invention is to hold two cylindrical objects 2 to be welded at a specific position on the same axis in space, and to attach the cylindrical objects 2 to other parts at that location. In a positioning jig for performing welding at a correct position, a positioning shaft 10 that is erected on a support base 9 and into which the cylindrical workpiece 2 is fitted has an outer diameter smaller than the inner diameter of the cylindrical workpiece 2. a sleeve-shaped outer shaft 21; a sleeve-shaped outer shaft 21;
1, and an inner shaft 22 that slides relative to the cylindrical workpiece 2 in the axial direction, and is provided on the peripheral wall of the outer shaft 21 corresponding to the installation position of the cylindrical workpiece 2. a centering member 26 that can freely protrude and retract from the outer surface of the peripheral wall of the outer shaft 21 toward the inner wall surface of the outer shaft 21; By controlling the axial position of the guide part 27 whose diameter dimension changes as shown in FIG. The centering member 26 is disposed at a protruding position having a function of centering the cylindrical workpiece 2 to lock the cylindrical workpiece 2.
The present invention is a positioning jig for a cylindrical workpiece, which is provided with a lock control device 30 that releases the lock by placing the workpiece in a retracted position having no centering function.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

In the embodiments shown in FIGS. 5 to 7, a positioning jig J for a king pin boss 2 as a cylindrical workpiece is shown, and the basic structure of this positioning jig J is as follows: It consists of a fixed support base 9 and a positioning shaft 10 erected on the support base 9.

In this embodiment, the support stand 9 is fitted into the hole 7a of the base plate 7, and a horizontal support surface 9a is formed on its upper surface, and a horizontal support surface 9a is formed in the center thereof in a direction perpendicular to the base plate 7. A penetrating bearing hole 20 is provided.

Further, as shown in FIGS. 5a and 5b, the positioning shaft 10 is composed of a sleeve-shaped outer shaft 21 and an inner shaft 22 that is inserted into the outer shaft 21. The outer shaft 21 has a king pin boss 2 and a collar 1.
1, and is formed integrally with the support 9 so as to surround the bearing hole 20 of the support 9. On the other hand, the inner shaft 22 is formed to have an outer diameter equal to the diameter of the bearing hole 20, and the axial length of the inner shaft 22 is set to be longer than the dimension from the lower end of the support base 9 to the upper end of the outer shaft 21. has been done. The lower part 22a of the inner shaft 22 is slidably fitted into the bearing hole 20 so that the inner shaft 22 can slide in the axial direction, and the upper end of the inner shaft 22 is connected to the upper end of the outer shaft 21. An upper stopper 23 is attached to the inner shaft 22, and a lower stopper 24 is attached to the lower end of the inner shaft 22. The upper stopper 23 and the lower stopper 24 limit the sliding range of the inner shaft 22. regulated. The inner shaft 22 is prevented from rotating relative to the outer shaft 21, and the upper stopper 23 of the inner shaft 22 also functions as a handle for sliding the inner shaft 22.

Furthermore, in a portion of the peripheral wall of the outer shaft 21 that corresponds to the location where the king pin boss 2 is disposed,
As shown in FIGS. 6a and 6b, for example, four ball accommodation holes 25 are provided in two rows in the axial direction at predetermined angular intervals, and each ball accommodation hole 25 has a ball as a centering member. 26 are housed in each. That is, the ball accommodation hole 25 is as shown in FIG.
As shown in b, the outer shaft 21 is inclined diagonally downward from the outer wall surface to the inner wall surface, and a hole is provided near the inner wall surface side of the outer shaft 21 of the ball receiving hole 25 to prevent the movement of the balls 26 in the radial inward direction of the outer shaft 21. A restricting stopper portion 31 is formed. As shown in FIGS. 6a and 7a, the ball 26 is always accommodated and held in the ball accommodation hole 25, and the outer shaft 21
The outer shaft 21 is disposed in a recessed position relative to the outer wall surface of the outer shaft 21, while being able to move in a radial direction outward of the outer shaft 21.

Furthermore, a guide portion 2 is provided at a portion of the inner shaft 22 that corresponds to the location where the ball 26 is disposed.
7 is integrally formed, and this guide portion 27
is the maximum outer diameter portion 27a of the inner shaft 22, and
It has a diameter-reducing portion 27b whose diameter is sequentially reduced from the maximum outer diameter portion 27a downward in the axial direction, and the lower end of the diameter reduction portion 27b is the minimum outer diameter portion 27c.
The inner end of each ball 26 is always in contact with this guide portion 27, and when the inner end of each ball 26 is in contact with the minimum outer diameter portion 27c of this guide portion 27, each ball 26 is in contact with the inner end of each ball 26 at all times. The ball 26 is housed in the ball housing hole 25.

Therefore, according to the positioning jig according to this embodiment, when the king pin boss 2 is set on the positioning shaft 10, the lower stopper 24 comes into contact with the lower end of the support base 9, as shown in FIG. 5a. After setting the inner shaft 22 to the raised position by sliding the inner shaft 22 upward to the position, the king pin boss 2 and collar 1 are attached to the positioning shaft 10.
1 should be fitted. At this time, when the inner shaft 22 is set to the raised position, the fifth
As shown in FIG. set to the position. Therefore, there are no protrusions on the outer wall surface of the outer shaft 21, and the king pin boss 2 and collar 11 fit smoothly into the outer wall surface of the outer shaft 21 with a clearance δ between them.

After this, when positioning the king pin boss 2, as shown in FIG. 5b, slide the inner shaft 22 downward until the upper stopper 23 contacts the upper end of the outer shaft 21, and All you have to do is set it to the lowered position.
At this time, the guide portion 2 together with the inner shaft 22
7 is moved and the inner shaft 22 is set to the lowered position, the maximum outer diameter portion 27a of the guide portion 27 is at the ball 26 position, as shown in FIGS. 5b, 6b, and 7b. I'm starting to reach that point. During this time, each ball 26
Each ball 26 is pushed radially outward while slidingly contacting the outer shaft 21, and each ball 26 is set at a position protruding from the outer wall surface of the outer shaft 21 and comes into contact with the inner wall surface of the king pin boss 2. In this state,
Since each ball 26 moves concentrically with respect to the axis O of the inner shaft 22, the kingpin boss 2 moves self-centripetally while being restrained by each ball 26, and the kingpin boss 2 moves concentrically with respect to the axis O of the inner shaft 22. and the axis O of the inner shaft 22 are aligned.

In this state, the positional relationship between the pre-positioned axle center 1 and the king pin boss 2 is determined, and they are welded together by a welding device not shown. At this time, the movement of the king pin boss 2 is restrained by each ball 26, so even if the king pin boss 2 is distorted due to welding heat, the axis of the king pin boss 2 will not be displaced. , the position of the king pin boss 2 with respect to the axle center 1 is maintained at a predetermined value.

Thereafter, when welding of both is completed, the king pin boss 2 is removed from the positioning jig J. In this case, after setting the inner shaft 22 again to the raised position shown in FIG. 5a, Attach the king pin boss 2 and collar 11 to the outer shaft 2.
All you have to do is remove it from 1. At this time, when the inner shaft 22 is returned to the raised position, each ball 26
Since the guide portion 27 that holds the outer shaft 21 in the protruding position moves, each ball 26 retreats from the protruding position due to the inclination of the ball accommodation hole 25 and returns to the retracted position. will not exist at all. Therefore, the king pin boss 2 and the collar 11 are easily separated with a clearance δ between them and the outer wall surface of the outer shaft 21. In this case, the king pin boss 2 is distorted due to welding heat, but
If the clearance δ is set to a certain degree, it will not affect the separation of the king pin boss 2 from the outer shaft 21.

Further, in this embodiment, the ball 26 is used as the centering member, and the ball accommodating hole 25 of the outer shaft 21 has a structure in which the ball 26 is simply inserted. In addition, the ball 26 accommodated in the ball accommodation hole 25 becomes extremely easy to
Since the ball 26 is stably held by the slope of the ball accommodation hole 25 and the stopper part 31, there is no fear that the ball 26 will fall out unnecessarily.

In addition, in the above embodiment, the outer shaft 2
1 is fixed and the inner shaft 22 is slidable, but the inner shaft 22 may be fixed and the outer shaft 21 is slidable.
Further, the number and arrangement of the balls 26 as the centering member are not limited to those shown in the above embodiments, and the design may be changed as appropriate.
For example, it is not necessary to use outer shaft 2.
Two or more rods may be provided that protrude and retract in the outward direction of one radius. Further, in the above embodiment, the guide portion 27 is formed on the entire circumferential surface of the inner shaft 22, but the guide portion 27 is not necessarily limited to this, and the guide portion 27 is formed on the entire circumferential surface of the inner shaft 22 at least in the portion of the inner shaft 22 corresponding to the ball 26. The portion 27 may be formed partially. In this case, the guide portion 27 may be a groove or a protrusion, as long as its diameter changes in the axial direction of the inner shaft 22. Furthermore, in the above embodiment,
Although the guide portion 27 is integrally formed on the inner shaft 22, a separate guide member may be attached to the inner shaft 22 to serve as the guide portion.
Further, in the above embodiment, the kingpin boss 2 is used as an example of the cylindrical object to be welded, but it goes without saying that the present invention can be applied to positioning jigs for other cylindrical objects to be welded. In this case, the number of cylindrical objects to be welded that are positioned by one positioning jig is not necessarily two as shown in the embodiments, but may be one, three or more.

As explained above, according to the positioning jig for a cylindrical workpiece according to the present invention, when the centering member is placed in the protruding position, the cylindrical workpiece is set to the centered state, This centering state is maintained without being affected by thermal distortion during welding, which not only improves the positioning accuracy of the cylindrical workpiece but also moves the centering member to the recessed position. When placing the workpiece in the welding position, sufficient clearance is secured between the cylindrical workpiece and the positioning shaft, and as a result, the positioning shaft can be easily moved from the positioning shaft to the positioning shaft without being affected by thermal distortion during welding. The shaped workpiece can be easily removed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of the main body and a cylindrical workpiece, Fig. 2 is a front view showing a conventional positioning jig for the main body and cylindrical workpiece, Fig. 3 is a plan view thereof, and Fig. 4 The figure is a cross-sectional view of a main part showing the details of a conventional positioning jig for a cylindrical workpiece, and FIGS. Fig. 5a is a sectional view showing the state when the cylindrical workpiece is set, Fig. 5b is a sectional view showing the state when the cylindrical workpiece is positioned, and Fig. 6a and b are sectional views taken along the line in Fig. 5a. 5b, and FIGS. 7a and 7b are an enlarged view of the middle part of FIG. 5a and a corresponding enlarged view of FIG. 5b. J...Positioning jig, 1...Axle center (main body), 2...King pin boss (cylindrical welded object), 9...Support stand, 10...Positioning shaft,
21... Outer shaft, 22... Inner shaft, 25... Ball accommodation hole, 26... Ball (centering member), 27... Guide portion.

Claims (1)

[Claims] 1 In a positioning jig that holds two cylindrical welded objects 2 at a specific position on the same axis in space and welds the cylindrical welded objects 2 to the correct position of other parts at that location. , a positioning shaft 1 erected on a support base 9 and into which the cylindrical workpiece 2 is fitted;
0, a sleeve-shaped outer shaft 21 having an outer diameter smaller than the inner diameter of the cylindrical workpiece 2;
an inner shaft 22 that is fitted into the outer shaft 21 and slides relative to the outer shaft 21 in the axial direction; A centering member 26 is provided on the peripheral wall of the outer shaft 21 so as to freely protrude and retract from the outer surface of the peripheral wall of the outer shaft 21 toward the inner wall surface of the cylindrical workpiece 2, and a centering member 26 is formed on the outer wall of the inner shaft 22 corresponding to the centering member 26. A guide portion 27 that engages with the centering member 26 and changes its diameter in the axial direction, and controls the axial position of the inner shaft 22 to adjust the relative axial direction of the guide portion 27 and the centering member 26. By changing the position of the centering member 26, the centering member 26 is placed in a protruding position having a function of centering the cylindrical workpiece 2, locking the cylindrical workpiece 2, and centering the centering member 26. A positioning jig for a cylindrical workpiece, characterized in that it is provided with a lock control device 30 that releases the lock when placed in a retracted position having no function.