JPS6231355Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a chain guide for motorcycles.

Motorcycles are generally driven by connecting the engine sprocket and rear wheel sprocket with a chain. The rear wheel is attached to the rear end of a swing arm whose front end is pivoted to the vehicle body so that it can swing and cushion. Under normal loads, the engine sprocket, the front end of the swing arm, and the rear wheel sprocket are arranged in a straight line, so when the swing arm swings up and down, the engine sprocket This will change the distance between the rear wheel sprockets and loosen the chain. If the chain becomes slack, it may come off the sprocket, so to avoid this, a chain tensioner is pressed against the chain to keep the chain tensioned at all times. However, since the chain tensioner is always pressed against the chain, it creates resistance and has the disadvantage of causing output loss.

In view of these points, this device has been improved so that it does not create resistance under normal load conditions and guides the chain to its normal position only when the chain is slack. I will explain about it.

The swing arm 1 has its front end pivoted to the vehicle body 3 via a support shaft 2, and is connected to a cushion unit (not shown), which swings up and down as shown by arrows A and B. cushion and rear wheels 4 at the rear end.
an axle 5 is attached. The engine sprocket 6 and the rear wheel sprocket 7 are connected and driven by a chain 8, and under normal loads, the engine sprocket 6, the support shaft 2, and the rear wheel sprocket 7 are aligned in a straight line. . Therefore, when the swing arm 1 swings upward or downward, the distance between the engine sprocket 6 and the rear wheel sprocket 7 changes to become closer, and the chain 8 becomes slack. By the way, the swing arm 1 has the base of the L-shaped arm piece 10 pivotally attached to the shaft tube 11, and a cross-sectional member having an elastic plate or the like stretched on the chain receiving surfaces facing the upper and lower surfaces of the chain 8 with a gap therebetween. A letter-shaped chain guide 9 is attached to the tip of one arm of the L-shaped arm piece 10, and the tip of the other arm is connected to the swing arm 1.
A tension spring 12, which is arranged along the swing arm 1 and expands and contracts in the axial direction thereof, is tensioned between the swing arm 1 and the swing arm 1.
When the arm piece 10 is at rest under the tension of the spring 12, the chain guide 9 is installed at a position where the chain 8 is in its normal position.

However, in the normal load position, the chain guide 9 is set to match the position of the chain 8, so even if the chain 8 swings and hits the chain guide 9, the chain guide 9 There is no pressure and there is little resistance. When the swing arm 1 is cushioned and the chain 8 is loosened, the chain guide 9 corrects the chain 8 so that it is in the correct position. When the chain 8 swings significantly due to torque fluctuations or shocks during compression, etc., tension the spring 12 and move the chain guide 9 along with the arm piece 10 to the chain 8.
can move together, absorb the shock, and then return to its correct position with the elasticity of the spring 12.

As explained above, in this invention, the base of the L-shaped arm piece is pivoted to the swing arm, and a gap is provided between the top and bottom surfaces of the chain at the tip of one arm of the L-shaped arm piece. A chain guide with a U-shaped cross section with opposing chain bearing surfaces is attached, and a tension spring that is placed along the swing arm and expands and contracts in the axial direction is stretched between the tip of the other arm and the swing arm. However, since the chain guide described above guides the chain so that it comes to the normal position, when the chain is in the normal load position,
Almost no resistance, preventing output loss. and,
When the swing arm is stiffened and the chain becomes slack, the chain guide can guide it to the correct position. Furthermore, since the chain guide moves against the spring, no unreasonable impact is applied to the chain.
The chain guide has high durability because it hardly touches the chain in its normal position. Further, the spring can be arranged along the swing arm, making it difficult to see from the outside and giving it a good appearance.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side view, FIG. 2 is an enlarged side view of the main part, and FIG. 3 is a front sectional view of the same. 1... Swing arm, 8... Chain, 9...
Chain guide, 10...arm piece, 12...spring.

Claims (1)

[Scope of utility model registration request] The base of the L-shaped arm piece is pivoted to the swing arm, and at the tip of one arm of the L-shaped arm piece,
A chain guide having a U-shaped cross section and having chain receiving surfaces facing each other with a gap is attached to the upper and lower surfaces of the chain,
A tension spring is placed between the tip of the other arm and the swing arm and extends and contracts in the axial direction of the swing arm, and the chain is moved to the normal position by the chain guide. A chain guide for motorcycles that is designed to guide you.