JPS6227736Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is equipped with an outer guide part and an inner guide part, and can absorb the slack of the chain and prevent the chain from floating when engaging and disengaging from the chain wheel, thereby reducing the noise of the chain. This invention relates to a chain tensioner that can reduce vibration and extend chain life.

For example, in a chain device that rotates at high speed, such as a camshaft drive of an engine of an automobile, two-wheeled motor vehicle, etc., as shown in FIG. A chain tensioner C, which has a guide part b in the center that can move inward as the chain stretches, has been used to absorb the slack, but the conventional chain tensioner C, which presses only the center of the chain span, , the chain vibration is changed from the first-order vibration mode d to the second-order vibration mode e
Although it is possible to reduce the amplitude f instead, the vibration of the chains on both sides of the chain tensioner c still adds a large chain tension, which promotes chain elongation and also prevents the chain from engaging and disengaging from the chain wheel. , it collides with the chain wheel teeth and causes floating, etc.
As a result of preventing smooth engagement and disengagement, noise is generated,
This led to a shortened lifespan.

The present invention aims to provide a chain tensioner that can solve these problems, and one embodiment thereof will be described below with reference to the drawings.

In FIG. 1, a chain tensioner 1 of the present invention includes a fan-shaped rubber body 2 whose lower surface forms an arc, and a hard rubber body curved downward, one end of which is embedded and fixed to the rubber body 2, and which is made of hard rubber over almost the entire length. One end of the spring piece 3 is embedded and fixed near the edge of the arcuate surface 4 of the rubber body 2, so that the spring piece 3 is connected to the center of the arcuate surface 4. Between the curved spring piece 3 and the central lower surface 4, a concave portion is formed that faces upward in the figure, and by attaching the concave portion,
The center part of the circular arc surface 4 of the rubber body 2 has an outer guide part A,
Further, the central lower surfaces 5 of the spring pieces 3 form inner guide portions B, respectively. The rubber body 2 is pivotally mounted within a groove of a mounting board 7 having a U-shaped cross section by a mounting bolt a6 inserted through a through hole 6a provided at the center of the arc, and the spring piece 3 is bent upward at the other end. A cylindrical part 8 is provided at the tip of the part,
The cylindrical portion 8 is pivotally attached to a slide piece 9 that can slide in the groove of the mounting board 7. The slide piece 9
The other end of the tension spring 11 is attached to the protruding piece 10 provided below near the rubber body 2 of the mounting board 7, and the slide piece 9 is slid by the biasing force of the tension spring 11 to release the spring. By curving the piece 3 convexly downwards in the figure, the inner guide B can be moved downwards.
In addition, a U-shaped piece 13 that passes through the mounting bolt b12 is welded to the upper surface of the mounting board 7, and as shown in the second figure in which the rubber body 2 and spring piece 3 are taken out, there is, for example, a driving force that rotates counterclockwise. The outer guide portion A of the rubber body 2 is attached to a chain device in which a chain 16 is wound around a chain wheel 14 for a camshaft and a chain wheel 15 for a camshaft, and a chain guide 17 is provided on the tension side of the chain.
Of the meshing contacts C and D defined as the points of contact between the pitch circles PC4 and PC5 and the chain traveling pitch straight line PL, there is a mesh contact point C and D defined as the contact points between the pitch circles PC4 and PC5 and the chain running pitch straight line PL. , using the mounting bolts a, b, 6, and 12. At this time, the inner guide part B of the spring piece 3 is arranged so as to press approximately the center of the chain span L between the meshing contacts C and D, and the space between the outer guide part A and the inner guide part B is Depending on the part, chain 16 is
When the chain 16 is at rest, the discontinuous portion E that creates a gap can be formed.

However, in the chain tensioner 1 of the present invention, as the chain 16 stretches, the spring piece 3
1, the inner guide part B presses the chain 16 and moves downward to absorb the slack, and the vibration mode can be made multidimensional. It is possible to smooth the engagement by suppressing the springing and floating during engagement, and as a result, the vibration of the chain can be effectively reduced, noise can be reduced, and the life of the chain can be extended.

FIG. 3 is a diagram showing another embodiment of the chain tensioner of the present invention, in which a bent portion 20 shaped like a bow is curved downward at the center and has rubber pieces 18 and 19 held at both ends. , 21 are provided below, the lower surfaces of each bent portion 20, 21 constitute outer guide portions A, A, and the meshing contacts C, D
It is attached by mounting bolts 22 and 23 embedded in the rubber pieces 20 and 21 near the chain 16 and with a small gap therebetween. By forming the bent portions 20 and 21 to be shorter than the base portion, interrupted portions E and E are formed between the outer guide portions A and A and the inner guide portion B. Moreover, the inner guide portion B is constantly pressed downward by a pressing tool 27 attached above and capable of irreversibly pressing the movable piece 26 by the pressure of the liquid flowing in through the ball valve 25. In this embodiment, the outer guide portions A and A have large circular arcs that are eccentric to the mounting bolts 22 and 23, so that the chain 16 and the chain can be easily connected to each other by rotation of the outer guide portions A and A as the chain is stretched and pushed down. A predetermined gap can be maintained at the actual meshing position with the wheels 14 and 15.

As mentioned above, the chain tensioner 1 of the present invention has an outer guide part A and an inner guide part B separated by a discontinuous part E, and the inner guide part B absorbs slack in the chain and presses the chain. The vibration mode of the chain can be changed to reduce the amplitude and the added tension due to chain vibration can be reduced, while the outer guide part A can reduce the impact when the chain and chain wheel are engaged and disengaged, and can also float. In addition to preventing chain vibration and enabling smooth engagement and disengagement, it also reduces the vibration length of the chain and suppresses the occurrence of chain vibration, and by providing a discontinuous part, the sliding length with the chain can be reduced. This reduces frictional resistance and prevents mutual interference between the outer guide part and the inner guide part. As a result, chain elongation and noise generation can be prevented, and chain life can be extended.

The chain tensioner of the present invention can be used in various types of chains such as roller chains and silent chains, and various types of chains such as rollers can be used as the outer guide part A, and outer guide part A and inner guide part B can be used. It may be constructed using separate members rather than as an integral part. It is also possible to use synthetic resin instead of so-called rubber as the material used.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the tensioner of the present invention, FIG. 2 is a diagram showing the arrangement in a chain device, FIG. 3 is a diagram showing other embodiments, and FIG.
The figure is a diagram illustrating a conventional device. 14...Chain wheel for driving, 15...Chain wheel for cam, 16...Chain, A...Outer guide section, B...
Inner guide part, C...mating contact, D...mating contact, E
... Interrupted part, L ... Chain span.

Claims (1)

[Scope of utility model registration request] an outer guide section disposed near the meshing contact point between the chain wheel and the chain and for preventing the chain from floating at that position; A chain tensioner having an inner guide section that can move while pressing the chain.