JP2516940Y2 - Chain tensioner device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a chain tensioner device used in a chain drive mechanism.

(Prior art) Up to now, a check valve is used to maintain the hydraulic pressure in a tensioner that uses a combination of spring and hydraulic pressure, but the hydraulic pressure that biases the plunger in the forward direction becomes significantly higher depending on the conditions of use, and the chain and tensioner band Not only did it cause unpleasant noise due to contact with the, but there was a problem with the durability of the tensioner itself.

Further, in order to solve the problem, the one provided with the relief mechanism has a drawback in that the high-pressure oil is discharged, so that there is a time loss until the recovery, and the followability to the chain vibration is poor depending on the use conditions.

(Problems to be Solved by the Invention) In order to solve the above-mentioned problems, the chain tensioner device according to the present invention is provided with a biasing means capable of following a sudden vibration of the chain so as to always apply a suitable hydraulic pressure to the plunger. A tensioner device is provided.

(Means for Solving the Problem) For this reason, according to the present invention, a piston that slidably defines an oil chamber is provided in the chain tensioner device, and the piston is provided outside between the piston and the bottom surface of the body. The piston is provided with an urging spring and an oil passage for supplying hydraulic oil to the plunger-side oil chamber and a check valve for preventing a reverse flow of the oil passage, and between the piston and the plunger. In addition, a spring is provided to urge the plunger in the advancing direction.

(Operation) In the above configuration, the spring for urging the plunger has a large stroke characteristic, so that the chain can be stretched and stretched without slack, following the elongation of the chain.
At this time, since the check valve secures the capacity of the oil chamber, the plunger's advanced position is maintained, and the spring for biasing the piston has an excessively large spring constant, which causes the plunger to be excessive from the chain side. When an appropriate force is applied, the plunger is allowed to move backward through the oil chamber and the piston to avoid the generation of abnormal acting force and noise.

As described above, in the chain tensioner device according to the present invention, different characteristics required for elongation and pressing force of the chain can be individually set corresponding to the above two springs, and therefore, it is possible to set abnormalities. It is possible to easily set the optimum characteristics according to the applied model so that the chain is appropriately tensioned and the durability is satisfied while preventing generation of acting force and noise.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
The figure shows the use state of the chain tensioner device according to the present invention, in which the tensioner band 21 is slid on the chain 20 and pressed by the tensioner device 1.

2 and 3 show an embodiment of the tensioner device of the present invention.
The figure shows a state in which the chain is stretched and the plunger is pushed in, and FIG. 3 shows a state in which the chain is flexible and the plunger is advanced.

The above embodiment will be described with reference to FIG.
Has a first hydraulic chamber 5 which is an oil chamber formed inside the plunger, a second hydraulic chamber 9 which is an oil reservoir for storing the discharged oil, and oil passages 13 and 14 which connect these hydraulic chambers to each other in the piston 7. It is located inside. The oil passage 13 is narrower than the oil passage 14 so as to give priority to the inflow of oil into the first hydraulic chamber, and in the second hydraulic chamber, the oil flowing from the oil passage 13 can be easily discharged from the discharge passage 17. It is discharged and is kept at a significantly lower pressure than the first hydraulic chamber.

Also, in order to prevent the sliding of the piston 7 from resonating with the movement of the plunger 3 due to an external force, the oil inflow passage 13 at the rear of the piston 7
And the viscous resistance due to the flow of oil from the second hydraulic chamber 9 through the oil discharge passage 17 of the body 2 is utilized.

The body 2 is provided with an oil inlet 1 leading to the oil passages 13 and 14.
6 is provided as shown in the figure. A plunger 3 is movably and airtightly fitted to the body 2, and an end portion of the plunger 3 presses the tensioner band 21.

A spring 4 for biasing the pressing of the plunger 3 is inserted inside the plunger 3, and one end of the spring 4 is supported by one end of the plunger 3 and the other end is supported by a piston 7. Further, a piston 7 is movably and airtightly fitted to the body 2.
A check valve 11 is provided on the upper part of the first hydraulic chamber 5 to prevent oil from flowing out when the hydraulic pressure in the first hydraulic chamber 5 is higher than that in the oil passage 14, and the hydraulic pressure in the first hydraulic chamber 5 is lower than that in the oil passage 14. When oil flows in. A spring 8 for urging the piston 7 is inserted inside the second hydraulic chamber 9, one end of the spring 8 is supported by one end of the piston 7, and the other end is supported by the body 2.

FIG. 2 shows the state in which the chain is stretched, and the oil supplied from the oil inlet 16 is the oil passage.
The oil passage 13 flows from 12 to fill the second hydraulic chamber 9 and is discharged from the oil passage 17. Since the plunger 3 is pushed in, the first hydraulic chamber 5 becomes higher in pressure than the oil passage 14, and the check valve 11 closes to prevent oil outflow, so that the piston 7 is retracted against the spring 8 and the pressure in the first hydraulic chamber 5 is reduced. It will be relieved and the chain will not be overly tensioned. This state is shown.

FIG. 3 shows the state in which the chain is bent, and the plunger 3 moves forward in the upward direction, and the hydraulic pressure in the first hydraulic chamber becomes low. Then, the piston 7 urged by the spring 8 advances in the upward direction, and the oil inlet port
The oil supplied from 16 flows into the oil passage 14 from the oil passage 12, passes through the oil passage 18 of the check valve 11, and flows into the first hydraulic chamber. This shows the state.

(Effect of the device) As described above, the tensioner device of the present invention uses both spring and hydraulic pressure, and the plunger always has an appropriate amount of retreat, so there is no need to push the chain with an abnormally large force, and the chain is fixed. The tension of the tensioner device itself can be improved, and the generation of noise due to contact between the chain and the tensioner belt can be prevented.

Further, compared with the conventional one, even if the hydraulic pressure in the plunger hydraulic chamber rises, the hydraulic pressure is adjusted without discharging the high pressure oil, so that the followability is improved and there is an advantage that noise can be prevented.

In addition, different characteristics required for chain elongation and pressing force can be set individually for each of the two springs, so that abnormal force and noise are prevented from occurring in the chain. Thus, it is possible to easily set the optimum characteristics according to the applied model so as to provide appropriate tension and satisfy the durability.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a chain tensioner device according to the present invention, FIG. 2 is an enlarged view of FIG. 1 showing a state in which a chain is stretched, and FIG. FIG. 7 is an enlarged view of the drawing and is a cross-sectional view showing a state where the chain is bent. FIG. 4 is a sectional view of a conventional example. 1 ... Tensioner device, 2 ... Body 3 ... Plunger, 4 ... Spring 5 ... First hydraulic chamber (oil chamber), 7 ... Piston 8 ... Spring, 9 ... Second hydraulic chamber (oil sump 11) Check valve, 12 ... Oil passage 13 ... Oil passage, 14 ... Oil passage 16 ... Inflow passage, 17 ... Discharge passage 18 ... Oil passage, 20 ... Chain 21 ... Tensioner band

Claims (1)

(57) [Scope of utility model registration request] 1. A chain tensioner device comprising a bottomed cylindrical body and a plunger that slides back and forth and an oil chamber formed inside the plunger. Is provided with a piston that slidably defines the oil chamber and a spring that biases the piston outwardly between the piston and the bottom surface of the body. An oil passage for supplying hydraulic oil to the oil chamber and a check valve for preventing reverse flow in this oil passage are provided, and a spring for urging the plunger in the advancing direction is provided between the piston and the plunger. A characteristic chain tensioner device.