JPH025149Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to a sprocket gear with a damper function.

(Prior Art) Sprocket gears, regardless of whether they are on the drive side or the driven side, generate a large amount of noise due to impact between the chain roller and the tooth surface and chain noise due to rotational fluctuations. In order to prevent this noise, as shown in Figs. 3 and 4, rubber dampers 3 with an outer diameter slightly smaller than the diameter of the bottom of the teeth 2 are attached to both sides of the wheel 1, and the link plates of the chain 4 to be suspended are attached. There is a method of making contact with the inner peripheral edge of No. 5. When the chain roller 6 shifts from linear running to circular motion and comes into contact with the bottom of the toothed part 2,
The link plate 5 acts to push the damper rubber 3 into the damper, thereby suppressing noise generation to a large extent.

On the other hand, when there is a rotational fluctuation in the sprocket gear, a circumferential impact occurs between the chain roller 6 and the teeth 2, causing noise. In response to this impact, as shown in FIG.
By separating them and connecting them with a cylindrical damper rubber 8, it is buffered and secondary noise is prevented by reducing rotational fluctuations and excitation force to the shaft, etc.

There is also a sprocket gear that has both of the above two functions (see Figure 1 of Japanese Utility Model Publication No. 56-26118).

However, if the damper rubber is baked so as to protrude from the outer surface as shown in FIGS. 3 and 4, there will be many burned areas on the edges, which can easily lead to peeling, and as shown in FIG. In this case, the areas where the damper rubber and the shaft hole and the wheel part are seized are insufficient, and there is a risk that the connection may separate due to the transmitted torque.

The material disclosed in Japanese Utility Model Publication No. 56-26118 also has the above-mentioned fear of peeling.

(Problem to be solved by the invention) In view of the current situation, this invention prevents the peeling of the damper rubber that directly or indirectly buffers the collision between the chain and the sprocket gear, and prevents the transmission of large torque. The purpose of the present invention is to provide a sprocket gear that can sufficiently withstand

[Structure of the idea]

(Means for Solving the Problems) In line with the above objectives, the sprocket gear of this invention has a cylindrical shaft hole portion and a wheel portion having an inner diameter larger than the outer diameter and toothed portions formed on the outer periphery using damper rubber. The wheel part is concentrically connected through layers, and the wheel part has a width sufficiently narrower than the width of the shaft hole part, and a cylindrical part slightly shorter than the width of the shaft hole part protrudes from the inner diameter part on both sides. It has a T-shaped cross section, and the damper rubber layer wraps both sides of the wheel part with the same width as the shaft hole.
Its outer diameter is set to a size that makes contact with the inner edge of the link plate of the chain suspended on the teeth.

(Function) In this way, in this sprocket gear, the inner edge of the link plate of the suspended chain comes into contact with the outer peripheral surface of the damper rubber, directly buffering the collision between the chain roller and the bottom of the tooth, and also between the wheel part and the shaft hole. The buffering effect in the circumferential direction between the teeth indirectly buffers the circumferential collision between the chain roller and the teeth caused by torque fluctuations, thereby significantly reducing chain noise.

The damper rubber has few edges where it is sewn, making it difficult to peel off. In addition, the wheel part has a T-shaped cross section,
Since it is embedded in the damper rubber, the seizing area is large, the bond is difficult to separate, and it can withstand large transmission torque.

(Example) In FIGS. 1 and 2, this sprocket gear has a ring-shaped wheel part 11 with teeth 12 on the outer periphery and a wide cylindrical shaft hole part 14 concentrically connected by a damper rubber 15. It is formed by combining with.

The wheel portion 11 has an inner diameter larger than the outer diameter of the shaft hole portion 14, and the shaft hole portion 14 is formed in the inner diameter portion of the wheel portion 11.
A cylindrical portion 13 having a width slightly shorter than the width of the cylindrical portion 13 is formed to protrude from both sides and has a T-shaped cross section.

The damper rubber 15 that connects the wheel part 11 and the shaft hole part 14 has the same width as the shaft hole part 14 and has the same width as the shaft hole part 14.
1 extends near the toothed portion 12 and completely encloses the cylindrical portion 13. The outer diameter dimension of the link plate 1 of the chain 16 suspended on the tooth portion 12 is
7 The inner edges are set to touch.

With the above structure, when this sprocket gear rotates, the suspended chain 16
The inner edge of the link plate 17 contacts the outer diameter of the damper rubber 15, buffering the roller 18 from abutting against the bottom of the toothed portion 12, and reducing noise. Also, wheel part 1
1 and the cylindrical damper rubber layer 15a between the shaft hole 14
provides a buffering relative displacement between the two in the axial direction, buffers the impact in the circumferential direction between the roller 18 and the toothed portion 12, and reduces noise.

Furthermore, the noise generated to some extent is removed from the shaft hole 14.
Since the noise is not transmitted in the shaft direction, the noise emission surface is limited to the wheel portion 11, and almost the entire surface is thickly covered with the damper rubber 15, which is extremely effective in reducing noise.

At the same time, the sewn surface of the damper rubber is widened to strengthen the bond, and there are fewer edges of the sewn surface that can cause peeling, resulting in superior durability.

[Effect of idea]

As mentioned above, the sprocket gear of this invention is
A T-shaped cross-sectional ring-shaped wheel part with teeth on the outer periphery and a cylindrical shaft hole are concentrically connected via a damper rubber, and the damper rubber wraps the wheel part leaving the teeth, and the outer circumferential surface is is in contact with the inner edge of the link plate of the chain, which prevents the damper rubber from peeling off and improves durability.It also directly and indirectly prevents the generation and radiation of noise, greatly reducing chain noise. effective.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view of a sprocket gear that is an embodiment of this invention, and Figure 2 is a partially cutaway side view of a sprocket gear that is an embodiment of this invention.
Fig. 3 is a side view of a conventional sprocket gear, Fig. 4 is a sectional view taken from Fig. 3 A-A, and Fig. 5 is a sprocket gear showing another conventional example. FIG. 11...Wheel part, 12...Tooth part, 13...
Cylindrical part, 14... Shaft hole part, 15... Damper rubber,
16...Chain, 17...Link plate.

Claims (1)

[Scope of utility model registration request] A cylindrical shaft hole portion and a wheel portion having an inner diameter larger than the outer diameter and teeth formed on the outer periphery are concentrically connected via a damper rubber layer, and the wheel portion is The damper rubber layer has a T-shaped cross section with a cylindrical part slightly shorter than the width of the shaft hole protruding from both sides, and the damper rubber layer wraps around both sides of the wheel part with the same width as the shaft hole. A sprocket gear, characterized in that its outer diameter is set to a size that makes contact with the inner edge of a link plate of a chain suspended on the teeth.