JPS6039559Y2 - chain tensioner device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cheno tensioner device used in a cheno drive mechanism.

A cheno tensioner is used in the cheno drive mechanism to prevent the cheno from loosening.The tensioner uses a spring or the like to press the tensioner body against the cheno to prevent the cheno from loosening and tighten it. It is configured to slide in the elastic direction due to tension fluctuations, and is configured to be lubricated to make this sliding smooth.

Conventional tensioners have a layout that includes an oil suction section for lubrication or damping, an oil reservoir, an orifice, a tensioner, and a cylinder section that holds and slides the tensioner.
It is often installed away from oil passages, etc., and is used independently for each model of prime mover, etc., and lacks versatility.

Therefore, the design, mechanism, and parts of the tensioner are required for each model, which is disadvantageous in terms of cost and cannot be said to be optimal for mass production.

The present inventor devised this invention in order to improve the above-mentioned disadvantages in the Cheno tensioner device, and the purpose is to incorporate all of the receiving mechanism, tensioner part, spring part, etc. into the tensioner mechanism as a unit. By integrating it, it is possible to increase versatility by assembling it as it is into the prime mover of each model, and by making it into a unit, it is possible to achieve compactness, simplify the structure, reduce the number of parts, etc. An object of the present invention is to provide a cheno tensioner device as described above.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view of the main parts of the prime mover, in which a camshaft 2 is attached to the upper part of the crankcase 1, and a crankshaft 3 for driving the camshaft is attached below the camshaft 2, each of which has a sprocket 4.
, 5 and a chain 76, and oil 7 is stored in an oil reservoir 8 at the bottom of the crankcase 1 so that a part of the sprocket 5 is submerged.

A slipper-like chain guide 9 is attached to one side of the chain 76 and slides on one side of the chain 76.
The oil 7 is carried upward along with the check 7 as the sprockets 4 and 5 move in the direction of the arrow.

The chain guide 9 described above is provided on the return side of the chain 76, and a chain tensioner 10 is provided on the other side of the chain 76, which is the forward path side.

The chain tensioner 10 is shown enlarged in FIGS. 2 and 3, and includes a tensioner body 11 that is long in the longitudinal direction of the chain 76 and slides into contact with the outer surface of the forward side 6a of the chain 76, and a tensioner body 11 that supports one end of the chain tensioner body 11. It consists of a bushing bar 12 that performs an elastic pressing action in the chain tensioning direction, a tensioner body 13 that slidably fits and supports the bushing bar 12, and a spring 14 compressed between the body 13, the bar 12, and the like.

The tensioner main body 11 is pivotally mounted at the lower end by a pin 15, and a mounting piece 11a provided at the upper part of the free end side of the main body 11 is attached to the pin 16 by sandwiching a bifurcated bracket part 12a formed at the tip of the bar 12. Pivotally attached for free swinging.

The body 13 has a base 13a pivotally supported on the crankcase side by a pin 17, and includes a cylinder portion 13b extending from the base 13a toward the chino 6 side and opening on the chino 6 side.

The elongated piston portion 12b of the bushing par 12 described above is fitted into this cylinder portion 13b so as to be able to slide freely while maintaining a slight clearance.

A cylindrical portion 13 of the body 13 having a piston portion 12b
The piston portion 12 of the bar 12 is located between the stepped portion 13d provided at the base of the bar 12 and the rear stepped portion 12c of the bracket portion 12a of the bar 12.
A spring 14, such as a coil spring, as described above is compressed so as to surround the outer periphery of the cylindrical part 13c of the body 13 at the tip part b, and this spring 14 presses the bar 12 side against the fixed side of the body 13 toward the chino 6 side. , the main body 11 pivotally attached to the bar 12 is pivotally biased in the counterclockwise direction in FIG. 2 about the fulcrum 15,
The forward side 6a of the Che 76 is made tense.

The load on the spring 14 is set to the minimum necessary to tension it when the chain is stationary, and when the chain 76 is relaxed, the spring 14 moves the bar 12 to the left in FIG. The tension of the check 711 is corrected by swinging it in the direction shown in FIG.

An oil reservoir chamber 18 that opens upward is formed in the upper part of the base 13a of the body 13, and the bottom 18a of this chamber is curved with the intermediate portion above the pin 17, and a deep recess 18 is formed on the outer end side of the bottom 18a.
b is formed, the chamber 18 is covered with a mesh body 19, and a check 76 is formed.
The oil 7a... splashed up on the outgoing side 6a of the filter is received and stored in the chamber 18, and before being stored in the chamber 18, the oil 7a... is filtered by a mesh body 19 and cleaned in the chamber 18. The fine dust that cannot be removed by the net 19 settles and is stored and held in the bottom 18a and the lower recess 18b, so that the recess 18b constitutes a fine dust reservoir.

An oil chamber 20 is formed between the rear end 12d of the piston portion 12b of the bushing par 12 and the rear end wall 13e of the cylinder portion 13b.

The cylinder portion 13b and the piston portion 12b are tilted so that their axes face upward in the installed state and the base 13a faces downward.

A communication chamber 21 is provided behind the rear end wall 13e of the cylinder portion 13b, and a steel ball 23 and a spring 23b having a diameter larger than the communication hole 22 of the chamber 21 with the chamber 20 and smaller than the inner diameter of the chamber 20 are provided on the front surface of the communication chamber 21. is fitted, thereby forming a one-way valve, and an orifice 24 is provided between the communication chamber 21 and the oil sump chamber 18 above it to connect the chambers 21.18.

The ceiling 20a of the oil chamber 20 is located below the piston part 12b, and a ring-shaped stopper 25 fixed to the cylinder part 13b in the axial direction is interposed between the one-way valve 23 and the rear end 12d of the piston part. The valve 23 and the rear end 12d
The movement of the steel balls forming the directional valve 23 is reduced by preventing interference with the piston portion 12b and by interposing the spring 23b.
Hysteresis during movement is reduced, and the piston portion 12
There is a ring groove 26 surrounding the rear circumference of b.
A plurality of them are provided spaced apart in the axial direction to obtain a labyrinth effect and suppress oil leakage from between the piston portion 12b and the cylinder portion 13b.

In the above, when the chain 76 is relaxed, the pusher 12 is biased by the spring 14 and slides in the chain tensioning direction, that is, to the left in FIG. 2, and presses the main body 11 against the chain 76.

As the bar 12 moves to the left, its piston portion 12b moves to the left, negative pressure acts in the chamber 20, and the one-way valve 23 opens the opening 22.
The communication chamber 21 and the chamber 20 communicate with each other, and the oil in the chamber 18 is sucked into the chamber 20 through the orifice 24.

That is, it performs the suction action of the pump.

When the piston portion 12b moves to the right in FIG. 2 due to a change in the tension of the chino 6, the one-way valve 23 rolls to the right and closes the opening 22.

In this case, before the valve 23 is closed, the oil in the chamber 20 is
1 into the chamber 18, but the flow rate is controlled by the orifice 24, suppressing and reducing the outflow of oil in the chamber 20 due to sudden retraction of the piston portion 12b.

When the piston part 12b moves backward, the hydraulic pressure in the chamber 20, which is closed by the one-way valve 23, hydraulically attenuates the backward impact of the piston part 12b, that is, the impact caused by fluctuations in the tension of the main body 11 and the bushing bar 15.

By the way, if air gets mixed into the chamber 20, the above-mentioned damping effect will be reduced, but since the chamber 20 is located below the piston section 12b, the air will move upward, causing a small gap between the piston section 12b and the cylinder section 13b. It is discharged into the outside air from the tip side through rearance, ensuring reliable operation.

As is clear from the above explanation, the tensioner device of the present invention has the function of hydraulically damping the impact of the push bar connected to the tensioner body due to tension fluctuations in the tensioner, All mechanisms, including the tensioner body with an oil reservoir chamber for supplying oil, etc., are integrated into a unit, so it can be attached to each model as a unit, increasing versatility and making it easier to use. In addition to mass production and cost reduction, it is also possible to make it more compact due to the above.
The structure is simple, and it has many advantages, such as being excellent in terms of responsiveness to tension fluctuations, air bleeding, and oil leak suppression.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a vertical sectional view of the main parts of the prime mover, Fig. 2 is an enlarged side view of the main parts of the ceno tensioner device, and Fig. 3 is the same main part. It is an enlarged view of the part. In the drawing, 10 is the tensioner, 11 is the tensioner body, 1
2 is a bush bar, 12b is a piston part, 13 is a body, 13b is a cylinder part, 18 is an oil reservoir, 20 is an oil chamber, 23
is a one-way valve, and 24 is an orifice.

Claims (1)

[Scope of utility model registration request] The cylinder part is provided with a bottom part and a cylinder part inclined downward, an oil chamber equipped with a one-way valve is provided at the bottom part of the cylinder part, and an orifice provided at one end part of the bottom part of the oil sump chamber that opens upward in the upper part of the base part. A tensioner body that communicates an oil chamber and an oil reservoir chamber through the tensioner body, and has a deep recess formed at the other end of the oil reservoir chamber, and a bushing bar in which a piston portion is slidably fitted into a cylinder portion of the tensioner body. and a hanging type tensioner body that contacts the outgoing side of the chain that splashes oil stored at the bottom of the crankcase, and is connected to the open end side of the cylinder part of the bush bar near the top thereof, and the tensioner body is connected to the bush bar. a pressure member that integrally presses the tensioner body toward the chain side; and a net that is fitted over the opening of the oil reservoir chamber of the tensioner body to which oil splashed by the chainer is supplied so as to filter the oil. A chenotensioner device consisting of a body.