JPH07185953A - Jig for positioning crankshaft - Google Patents

Abstract

PURPOSE:To improve the positioning precision when a two-split crankshaft is combined, and prevent the weight bending in press fitting a pin. CONSTITUTION:A center pin 13 to be engaged with a center hole 8 formed in the end part of a crankshaft 6 is arranged in a jig 5. This center pin 13 presses the crankshaft 6 by the energizing force of a spring 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankshaft positioning jig for inserting, holding and positioning a crankshaft when a pin is press-fitted into the weight of the crankshaft divided into two parts.

[0002]

2. Description of the Related Art Conventionally, a crankshaft of a motorcycle is divided into two, one crankshaft is fitted and held by a crankshaft positioning jig attached to a base, and the other crankshaft is vertically movable above the base. Insert and hold the crankshaft positioning jig attached to the arranged press-fitting ram so that the weight of each crankshaft faces up and down, and locate the pin inserted in the connecting rod between them to lower the press-fitting ram. A crankshaft pin press-fitting device is known in which pins are press-fitted into the weights of the upper and lower crankshafts.

And in such a press-fitting device,
Each crankshaft is positioned by each crankshaft positioning jig and pin hole positioning knock pin.

[0004]

In the above-mentioned conventional crankshaft positioning jig, since the structure is such that the crankshaft is simply inserted and held, the crankshaft outer peripheral surface is affected by the tolerance of the crankshaft. A gap may be generated between the crankshaft and the shaft. If the gap becomes large, the weight bends when the weight is inserted, and the crankshaft swings when the weight rotates. If the gap is made small, it becomes difficult to insert and remove the crankshaft from the jig.

[0005]

In order to solve the above problems, the present invention provides a center pin in a jig which engages in a center hole formed at an end of a crankshaft. Further, it is preferable that the center pin is supported by a spring.

[0006]

[Function] Since the center pin engages in the center hole when the crankshaft is fitted and held in the crankshaft positioning jig, the centering of the crankshaft is improved, and the weight bending during pin press-fitting can be suppressed. it can.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view of a pin press-fitting device to which the crankshaft positioning jig according to the present invention is applied, and FIG.
[Fig. 3] is an enlarged sectional view of the jig.

In this pin press-fitting device, a press-fitting ram 2 is vertically movable on a base 1, and the base 1 and the press-fitting ram 2 are arranged.
Jig holding members 3 and 4 are attached respectively to the jig holding members 3 and 4, and crankshaft positioning jigs 5 and 5 are held on the jig holding members 3 and 4, respectively. The crankshafts 6 and 6 are fitted and retained for positioning, and the weights 7 of the crankshafts 6 are opposed to each other in the vertical direction.

The crankshaft positioning jig 5 is shown in FIG.
As shown in FIG. 3, a shaft holding hole 11 through which the large diameter portion 6a, the intermediate portion 6b and the small diameter portion 6c of the crankshaft 6 are inserted is formed, and a pin holding hole 12 is formed continuously with the shaft holding hole 11. ing. The shaft holding hole 11 of the jig 5 has a portion into which the large diameter portion 6a of the crankshaft 6 is inserted and has substantially the same diameter as the large diameter portion 6a.
The other portions through which the intermediate portion 6b and the small diameter portion 6c are inserted have a larger diameter than the intermediate portion 6b and the small diameter portion 6c so that a gap is formed between them and the outer peripheral surface thereof.

In the pin holding hole 12 of the jig 5, there is a center pin having a conical tip that engages with a positioning center hole 8 formed at the end of the small diameter portion 6c of the crankshaft 6. A holder 1 in which a shaft 13a of the center pin 13 is screwed to an end of a jig 5 by slidably fitting and inserting a shaft 13a.
4, a collar 15 is fitted and inserted into the end of the nut 4, and a nut 16 is screwed. A spring (disc spring) 18 that presses the center pin 13 between the lower surface of the center pin 13 and the collar 17 provided on the upper surface of the holder 14.
Is intervening. The jig 5 has an air vent hole 5 on its side.
a and 5b are formed.

When the pin 10 inserted into the connecting rod 9 is press-fitted into the weights 7, 7 of the crankshafts 6, 6 by the pin press-fitting device constructed as described above, first, the crankshafts 6, 6 are crankshaft positioning jigs. It is inserted and held in the tools 5 and 5.

At this time, the large diameter portion 6 of the crankshaft 6
a is fitted into the shaft holding hole 11 of the jig 5 and is substantially positioned within the range of dimensional tolerance, and the tip of the center pin 13 is engaged with the center hole 8 at the end of the crankshaft 6. The crankshaft 6 is accurately centered. The center pin 13 moves the crankshaft 6 by, for example, 40 to 50 k due to the urging force of the spring 18.
Although the pressure is applied with a load of g, the load can be adjusted by changing the thickness of the collar 17.

Then, as shown in FIG. 1, with the crankshafts 6 and 6 held by the jigs 5 and 5 of the base 1 and the press-fitting ram 2 and the weights 7 and 7 face each other, the connecting rod 9 is formed.
The pin 10 inserted in the pin is positioned at a predetermined position, and the press-fitting ram 2 is lowered to press-fit the pin 10 into the pin holes 7a, 7a formed in the weights 7, 7.

At this time, since the large diameter portion 6a of the upper end of the crankshaft 6 is held by the shaft holding hole 11 of the jig 5 and the center pin 13 is engaged with the end portion, the large diameter portion 6a.
Even if there is a gap due to the dimensional tolerance, since the end portion is restricted by the center pin 13, the end portion is prevented from swinging, so that the bending of the weight 7 is suppressed. Therefore, the swing of the weight 7 when the crankshaft 6 rotates is prevented.

Although the load of the center pin 13 can be adjusted by exchanging the collar 17 in the above-mentioned embodiment, the adjuster member can be screwed to the holder 14 so that the load can be adjusted. You can also

[0016]

As described above, according to the present invention,
Since the center pin that engages with the center hole formed at the end of the crankshaft is provided in the jig, the positioning accuracy is improved when the crankshaft is set, and the bending of the weight when pressing the pin is suppressed. And the rotation of the crankshaft is stable. Further, since the gap between the jig and the crankshaft can be enlarged to some extent, the crankshaft can be easily inserted into and taken out from the jig, and the workability is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a pin press-fitting device to which a crankshaft positioning jig according to the present invention is applied.

FIG. 2 is an enlarged sectional view of a crankshaft positioning jig.

[Explanation of symbols]

1 ... Base, 2 ... Press-fitting ram, 5 ... Crankshaft positioning jig, 6 ... Crankshaft, 7 ... Weight, 8 ...
Center hole at the end of the crankshaft, 9 ... connecting rod, 10 ... pin, 13 ... center pin, 14 ... holder,
18 ... Spring.

Claims (2)

[Claims] 1. A crankshaft positioning jig for inserting and holding the crankshaft for positioning when a pin is press-fitted into the weight of the crankshaft divided into two parts. A positioning jig for a crankshaft, wherein a center pin that engages with a center hole formed in the portion is provided. 2. The crankshaft positioning jig according to claim 1, wherein a spring that presses the center pin is interposed between the back portion of the center pin and the jig end portion.