JPS6095247A - Chain tensioner - Google Patents

Abstract

PURPOSE:To restrain noise and fluctuation in rotation by applying to a chain fixed spring force corresponding to rotational frequency of the chain and pressing force proportioned to the spring force in opposition thereto and controlling chain tension to be in inverse proportion to the rotational frequency. CONSTITUTION:When a chain 2 is turned between driving and driven sprockets 1, 2, a pressing member 4 of a tensioner 5 is brought into slidable contact with the inside of the chain 3, and fixed spring force corresponding to the rotational frequency is applied to the pressing member 4. Oil pressure proportioned to the rotational frequency is supplied to a chamber 12 of a hydraulic cylinder 9 to work upon the pressing member 4 through a piston 10 in opposition to the spring force. The pressing force inversely proportional to the rotational frequency is worked upon the chain 3 through the pressing member 4 by the above spring force and oil pressure force, whereby chain tension is set in such a manner to be strong at low rotation and weak at high rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chain tensioner that is installed in a chain transmission mechanism and applies tension to the chain, and particularly to one that adjusts the chain tension according to the number of rotations.

Regarding this type of chain tensioner, there is a prior art, for example, Japanese Utility Model Publication No. 53-1441, which proposes applying a spring force or the like to the chain midway through the chain to keep the chain tension constant. There is.

By the way, in general, in a chain transmission system, fluctuations in torque and rotation are large at low speeds, and this causes the chain to vibrate strings and generate abnormal noise, so the chain tension is increased at such low speeds. It is desired that -h1
At high rotations, there is little string vibration due to the torque fluctuations mentioned above, but if the chain tension is too strong, it will cause meshing noise between the chain and sprocket. It is desirable to weaken the tension.

However, when the chain tension is made constant as in the prior art described above, the above-mentioned JS! No sound countermeasures can be taken.

The present invention provides a chain tensioner that suppresses and suppresses noise and rotational fluctuations by optimizing chain tension relative to the rotational speed in view of noise generation due to the rotational speed of the chain. The purpose is to

For this purpose, the present invention is configured to apply a spring force to the chain and apply hydraulic pressure in opposition to the spring force, and by varying this hydraulic pressure with the number of rotations etc., the chain pressing force is applied. , that is, increase the chain tension at low speeds (
The gist of this is to control the power so that it becomes weaker at high speeds.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.a In Fig. 1, the overall outline of the chain transmission mechanism will be described.
2 is a driven side sub [l kerato], and between these sprockets 1 and 2, chains 3 and 3 are engaged to form a tensioner 5 (= J), which has a suppressing member 4 in the middle of the chain 3. is installed attached to the chain guide 6.

As detailed in FIG. 2, the tensioner 5 is made swingable by supporting the pressing member 4 at one end with a pin 7.
The free end side of the chain 3 is in sliding contact with the inside of the chain 3, and the spring 8 from the chain guide 6 is attached to the free end (=J
Forced. In addition, the chain guide 6 is equipped with a hydraulic cylinder 9.
A rod 11 integral with the screw 10 of this cylinder 9 passes through the inside of the spring 8 and is connected to the free end of the pressing member 4, and the rod 11 is connected to the free end of the pressing member 4 against the piston 10 in the cylinder 9. It has a hydraulic chamber 12 on the side. and,
The hydraulic chamber 12 communicates with the governor 14 via an oil passage 13 and is supplied with hydraulic pressure corresponding to the rotation, and thus the hydraulic pressure acts against the force of the spring 8.

7C1 In order to eliminate the influence of oil pressure changes due to oil temperature when used in situations where the outside temperature changes greatly, the above-mentioned hydraulic chamber 12
communicates with a hydraulic pressure adjustment device 16 via an oil passage 15 as required. The hydraulic adjustment device 16 is a boat 17 connected to the oil passage 15.
A valve body 20 is disposed in a chamber 19 having a drain boat 18 and a spring 21 is biased on one side of the valve body 20, and a temperature-sensitive substance 22, a diaphragm 23, and an incompressible substance 2 on the other side.
4 and fixed side support member 25 are arranged linearly,
When the temperature is low, such as during winter, the boat 11 is opened by the valve body 20 to uniformly lower the oil pressure in the hydraulic chamber 12.

The operation of the chain transmission mechanism configured in this way is explained using Fig. 3. The sprockets 1 on the drive side and the driven side
．． When chain 3 rotates between
The suppressing member 4 of the tensioner 5 is in sliding contact with the inside of the tensioner 5, and a constant spring force is applied to the suppressing member 4 with respect to the rotational speed of the spring 8 as shown by curve a in FIG. On the other hand, the hydraulic pressure chamber 12 of the hydraulic cylinder 9 is supplied with hydraulic pressure that tends to be proportional to the rotational speed as shown by the curve in the figure, and this hydraulic pressure is applied to the suppressing member 4 by the piston 10 against the spring force. act. Therefore, due to these spring forces and hydraulic pressure, the chain 3 is applied to the chain 3 via the suppressing member 4 according to the curve 0 in the same figure.
A pressing force that is inversely proportional to the rotational speed as shown by is applied, and along with this chain pressing force, the chain tension is set to be strong at low rotational speeds and weak at high rotational speeds.

Furthermore, in the case of the oil pressure adjusting device 1G, the oil pressure is reduced by the oil pressure adjusting device 16 in response to the fact that the oil pressure supplied to the hydraulic chamber 12 becomes higher due to the low oil temperature at low temperatures. Therefore, even in the case of changes in oil pressure due to oil temperature, the chain tension is maintained at a constant level without being affected by the change in oil pressure.

As described above, according to the present invention, the tension of the chain 3 is set by the tensioner 5 to be stronger at low rotations and weaker at high rotations in relation to the rotation speed, so that the noise of string vibration when the chain 3 rotates at low rotations and the tension at high rotations are reduced. At the same time, meshing noise is reduced. Furthermore, since the chain tension is strong at low rotations, fluctuations in rotation on the driven side can be suppressed. Since the chain tension is set in inverse proportion to the number of rotations, no unreasonable force is applied to the chain 3, and its rotation is always smooth, extending the life of the chain 13. Furthermore, if the hydraulic pressure adjustment device 1G is installed, the seasonal factors of winter and summer are eliminated, and the above-mentioned effects can be always exhibited.

[Brief explanation of drawings]

FIG. 1 is a side view of an embodiment of the present invention together with a chain transmission mechanism, FIG. 2 is a 4rII diagram of the main parts, and FIG. 3 is a diagram showing the relationship between rotational speed and force. DESCRIPTION OF SYMBOLS 1... Drive side sprocket, 2... Driven side sprocket, 3... Chain, 4... Suppression member, 5...
Tensioner, 6... Chain guide, 8... Spring, 9... Hydraulic cylinder, 12... Hydraulic chamber, 13
．． 15...Oil passage, 14...Governor, 16...Hydraulic pressure adjustment device. Figure 1 Figure 3 Mouth 1 Kei 9; Figure A2

Claims (1)

[Claims] The chain is characterized by being configured such that a spring force that is constant with respect to the number of rotations and a pressing force that tends to be proportional to the spring force are applied to the chain in opposition to each other, so that the chain tension is controlled in inverse proportion to the number of rotations. Chain Tenshina.