JPH0535042B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a method for manufacturing a sprocket for a chain saw that engages with a saw chain for cutting down trees and is rotated and driven by engine power. It is related to.

(b) Prior art and problems to be solved Conventionally, this type of sprocket has disc-shaped side plates 1 on both sides, a spline-shaped inner diameter hole 2, and a sprocket in the center, as shown in FIGS. 7 to 9. Since each part such as the tooth profile 3 and the notch groove 5 for releasing chips are integrally formed by casting, there are disadvantages such as the mold is complicated and difficult to manufacture, and it is not suitable for mass production. It was hot.

(c) Means and operation for solving the problem The present invention provides two disc-shaped side plates 29 formed by punching with a plurality of notched grooves 31 radially on one side. A middle plate 37 is formed by punching a sprocket tooth pattern 25 whose outer periphery almost coincides with the outer periphery of the side plate 29, and a notch groove 31 is formed between the tooth patterns 25. The structure consisted of a first step of adhering after positioning them, and a second step of punching and forming an inner diameter hole 19 in the center of the bonded side plates 29 and middle plate 37.

The present invention thus facilitates the manufacture of sprockets for chain saws through simple processing using a press machine or the like, and also enables mass production.

(d) Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In Figures 1 to 6, the engine (not shown)
A centrifugal clutch 9 is attached to the end of the crankshaft 7 which is rotated by the power of Press against the inner peripheral surface. A spline-shaped boss shaft 15 is fixed to the center of the clutch drum 13, and an inner diameter hole 16 is bored in the center of the boss shaft 15. freely supported. Furthermore, the boss shaft 15 engages with a spline-shaped inner diameter hole 19 of the sprocket 18. Further, a nut 21 for preventing the sprocket 18 from falling off is screwed onto the end of the boss shaft 15 via a washer 23. A saw chain 27 is engaged with the teeth 25 of the sprocket 18, and the saw chain 27 is used to cut down trees.

The sprocket 18 is constructed as follows. That is, what is shown in FIGS. 3 and 44 is a disc-shaped side plate 29 made of a steel plate.
An inner diameter hole 19 is provided in the center, which is punched out using a press machine. Further, on one side of the side plate 29, a notch groove 31 for releasing chips is provided in a radial direction from the center, and a plurality of pins 33, 33, . . . for positioning during machining are provided.
is provided. The one shown in FIGS. 5 and 6 is made of steel plate, has sprocket teeth 25 on the outer periphery, and has a punched middle plate 37.
A notch hole 39 (corresponding to the spline part of the spline inner diameter hole 19 described later) is provided in a radial direction from the center, and a plurality of pin holes 41 for positioning during processing are provided. 4
1,... are provided to penetrate. These two side plates 29 are placed so that the side surfaces provided with the cutout grooves 31 face each other, and the middle plate 37 is sandwiched between them.
1 by engaging the pin hole 33 for positioning, and bonding by brazing. (1st step). Further, a spline-shaped inner diameter hole 19 is punched out in the center of the bonded side plate 29 and middle plate 37 by a press machine to cut out a circular shape so as to connect the middle portions of the notch holes 39 to each other. (Second step).

In the above embodiment, when the engine is driven, the crankshaft 7 rotates, and the centrifugal clutch 9 and the boss shaft 1
The sprocket 18 rotates via the sprocket 5. Saw chain 27 that meshes with tooth pattern 25 of sprocket 18
rotates while being supported by both sides of the side plate 29, and this saw chain 27 is used to cut down trees and the like.

(e) Effect of the invention As described above, since the present invention has the structure as described in the claims, there is no need to manufacture complicated molds, and simple bonding processes such as brazing and spot welding can be performed. Since it can be manufactured through a punching process, manufacturing is simple and mass production is possible.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a part of a chain saw equipped with the device of the present invention, FIG. 2 is a side sectional view of one embodiment of the present invention, FIG. 3 is a front view of the same side plate, and FIG. Third
Figure 5 is a front view of the middle plate, Figure 6 is a side sectional view taken along the line - in Figure 5, Figure 7 is a side sectional view taken along the line -
The figure is a front view of the conventional sprocket, and Figure 8 is the 7th sprocket.
A side sectional view taken along the - line in the figure, Figure 9 is the - line in Figure 8.
It is a front cross-sectional view of the line. 19...Inner diameter hole, 25...Tooth shape, 29...Side plate, 37
...Middle plate.

Claims (1)

[Claims] 1. Two disc-shaped side plates 29 formed by punching with a plurality of notch grooves 31 radially formed on one side.
are aligned so that the notch grooves 31 face each other, and between them, a middle plate 37 is formed by punching a sprocket tooth pattern 25 whose outer periphery almost coincides with the outer periphery of the side plate 29. Notch groove 31
a first step of gluing after positioning so that the side plates 29 and the middle plate 37 are bonded;
A method for manufacturing a sprocket for a chain saw, comprising a second step of punching out an inner diameter hole 19 in the center of the sprocket.