JPH0529399Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a chain tensioner used in a cam chain or the like of a four-stroke engine.

[Technical background and problems of the invention]

In a 4-stroke engine, the sprocket of the crankshaft and the sprocket of the camshaft are connected by a chain and work together, and the cam of the camshaft opens and closes the intake and exhaust valves. Chains stretch as they are used, and when they loosen, they make flapping noises and cause errors in the opening and closing timing of intake and exhaust valves, so chains are always kept taut using a chain tensioner. Generally, a tensioner band is placed around the outer circumference of the chain, and the tensioner band is pushed by a spring-biased adjuster rod to press the tensioner band against the chain and keep the chain tensioned. However, in Asia star rod,
If the tensioner band is pushed from the rear side, the adjuster star body will protrude to the side of the crankcase or cylinder, increasing its size and causing problems such as getting in the way when installing the carburetor.

[Purpose of invention]

In view of this, the object of this invention is to provide a chain tensioner that can be compactly accommodated in a space within a crankcase or cylinder, as well as an adjuster star body and an adjuster rod of the chain tensioner.

[Structure of the idea]

Hereinafter, embodiments of the present invention shown in the drawings will be described.

The adjuster rod 1 is constructed by inserting a spring 2 inside the adjuster rod 1, and compressing the spring 2 into the cylinder of the adjuster star body 3.
is urged so that it protrudes outward, and is slidably inserted. Adjuster star rod 1 is ratchet 4
So, it can protrude outward, but it cannot go back inward. The tensioner band 5 is attached to one side of the outer periphery of the chain 6, its upper end is pivoted to the cylinder head via a shaft 7, and an arm piece 8 is fixed to its lower part. The arm piece 8 extends inwardly through the side of the chain 6. The adjuster star body 3 is disposed on one side of the chain tensioning surface, and its bottom end is connected to a shaft 10 implanted in a cylinder or crankcase 9 on the side opposite to the chain 6 with respect to the tensioner band 5. It is attached to the shaft. The tip of the adjuster rod 1 is pivoted to the tip of the arm piece 8 with a pin 11 on the opposite side of the chain to the pivoting portion at the bottom end of the adjuster star body.

The adjuster rod 1 protrudes due to the elasticity of the spring 2 and presses the tensioner band 5 against the chain 6 via the arm piece 8 to keep the chain 6 in a tensioned state.
As the chain 6 extends, the arm piece 8 changes around the axis 7 as shown by the two-dot chain line. On the other hand, the adjuster star rod 1 and the adjuster star body 3 are each pivoted and can follow the rotation accordingly. The adjuster star body 3 can be placed on the side of the chain 6 and effectively installed in the space within the cylinder or crankcase 9.

[Effect of idea]

As explained above, in this invention, the adjuster star body into which the adjuster star rod, which is biased in the projecting direction by a spring, is slidably inserted, is disposed on one side of the chain tensioning surface, and the adjuster rod is slidably inserted into the adjuster star body. The bottom end of the star body is pivoted to the case on the side opposite to the chain with respect to the tensioner band, and the tip of the adjuster star rod is pivoted to the tip of the arm piece attached to the tensioner band. is disposed on the opposite side of the chain from the shaft attachment part at the bottom end of the adjuster star body, so the amount of outward protrusion of the adjuster star body within the chain tensioning surface can be reduced. It can be effectively mounted within the space of a cylinder or crankcase, making it compact and space-saving.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is an enlarged front view of the main part, and FIG. 3 is a longitudinal sectional plan view of the same. 1...Asia star rod, 2...Spring, 3...
...Asia star body, 5...Tensioner belt,
8... Arm piece, 9... Case.

Claims (1)

[Scope of utility model registration request] In a chain tensioner equipped with a tensioner band that spans a chain between a driving shaft and a driven shaft, one end of which is pivoted to a case, and the other end of which is pressed in the direction of tensioning the chain, the adjuster is biased in the direction of protrusion by a spring. When the adjuster star body into which the rod is slidably inserted is placed on one side of the chain tensioning surface,
The bottom end of the adjuster star body is pivoted to the case on the side opposite to the chain with respect to the tensioner band, and the tip of the adjuster star rod is pivoted to the tip of the arm piece attached to the tensioner band. A chain tensioner characterized in that a part is disposed on the opposite side of the chain to a shaft attachment part at the bottom end of an adjuster star body.