JPH0719300A - Structure of chain tensioner - Google Patents

Abstract

PURPOSE:To provide an increased life for a tensioner through reduction of the generation of vibration of a pad by a method wherein a protrusion is formed on the side of the end part of a pad extruded by a plunger and a different protrusion making contact with the protrusion is formed on a pad opposite surface. CONSTITUTION:A protrusion 18 is formed on the side of the end part of a pad 9 and protrusions 19 are formed at height enough to cause the protrusion 18 to make contact with a pad opposite surface 7, positioned facing the side of the pad 9, with the protrusion 18 nipped therebetween. When a chain is moved in a state that a tension is exerted on the chain by means of the pad 9, the pad 9 is oscillated owing to microinclination of a sprocket and vibration of the chain. The oscillation is constrained by contact of the protrusions 18 and 19 with each other and minimized. This constitution minimizes rotation of the plunger 6 and a twist, normalizes engagement between the rack 14 and the ratchet 16, and prevents the occurrence of deviated wear between the rack 14 and the ratchet 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a chain tensioner which is improved so as to prolong the service life of the chain tensioner and prevent the vibration of the chain.

[0002]

2. Description of the Related Art First, a mode of use of a chain tensioner will be described by taking an engine timing chain as an example. In FIG. 6, a chain 3 is hung on a driving sprocket 1 and a driven sprocket 2, and a chain tensioner 4 is provided between the driving sprocket 1 and the driven sprocket 2 to adjust the tension of the chain and prevent the vibration of the chain 3. I am trying.

As shown in FIG. 7 (Japanese Utility Model Laid-Open No. 58-82555), a conventional chain tensioner 4 has a plunger 6 slidably provided in a body 5, and a pad 9 is attached to the tip of the plunger 6. There is. Further, a hydraulic chamber 10 is formed in the plunger 8, a spring 11 is provided in the hydraulic chamber 10, an end of the spring 11 is received by a spring receiver 12, and a check ball 13 is provided in the spring receiver 12.

By supplying the oil into the hydraulic chamber 10, the hydraulic pressure in the hydraulic chamber 10 acts on the check ball 13, which pushes out the plunger 6 to move the pad 9 to the chain 3.
Press to adjust the tension of chain 3. After adjusting the tension of the chain 3 in this way, a rack 14 is formed on the surface of the plunger 6 in order to keep the tension of the chain 3 constant with the hydraulic pressure OFF, and the pin 15 is engaged with the rack 14 so as to mesh with the rack 14. The ratchet 16 is rotatably supported by the ratchet 16 so as to hold the amount of protrusion of the plunger 6. Reference numeral 17 elastically regulates the rotation of the ratchet 16, and elastically supports the pressing force of the pad 9 against the chain together with the elastic force of the spring 11.

[0005]

In the above conventional tensioner, the drive sprocket 1 and the driven sprocket 2 are used.
Due to a mounting error or the like, a slight inclination between the drive sprocket 1 and the driven sprocket 2 or a shift in the chain line, or vibration of the chain 3 causes the pad 9 pushing the chain 3 to swing and the plunger 6 to rotate. To be made.

As described above, when the plunger 6 is rotated, an unreasonable force acts on the engagement between the rack 14 and the ratchet 16, causing an abnormal contact between the two, and the rack 14 and the ratchet 16 are eccentric. There is a problem in that the function of the ratchet 14 that prevents the vibration of the chain 3 by holding the protruding amount of the plunger 6 by pressing the pad 9 against the chain 3 is impaired and the service life of the tensioner is shortened.

The present invention reduces the swing of the pad 9 to prolong the service life of the chain tensioner.
It provides the structure of a chain tensioner.

[0008]

Means for Solving the Problems According to the present invention for solving the above-mentioned problems, in a chain tensioner in which a chain pushed around a sprocket is pushed by a pad pushed out by a plunger to eliminate looseness of the chain, A protrusion is provided on the side surface of the end portion of the pad, the height of the protrusion is set to a height for contacting the pad facing surface, and another protrusion for contacting the protrusion is provided on the pad facing surface. .

[0009]

Since the present invention is constructed as described above, it has the following effects. That is, since a protrusion is provided on the side surface of the end of the pad pushed out by the plunger and the height of the protrusion is set to be the height at which it abuts against the pad facing surface, the swinging of the pad in the direction of rotating the plunger causes the swinging of the pad in the direction between the protrusion and the pad facing surface. It becomes possible to be restrained by the contact between and. Further, since another protrusion is provided on the pad-opposing surface so as to abut the protrusion provided on the pad, the swinging of the pad in the direction of bending the plunger is between the protrusion provided on the pad and the protrusion provided on the pad-opposing surface. It becomes possible to restrain by contact.

[0010]

EXAMPLE An example of the present invention will be described below. The structure of the chain tensioner 4 shown in FIGS. 1 and 2 is
The structure is the same as the structure shown in FIG. That is, a plunger 6 is slidably provided in the body 5, a pad 9 is attached to the tip of the plunger 6, a hydraulic chamber 10 is formed in the plunger 6, and a spring 11 is provided in the hydraulic chamber 10. 11 ends are spring receiving
A check ball 13 is provided inside the spring receiver 12.

By supplying the oil into the hydraulic chamber 10, the hydraulic pressure in the hydraulic chamber 10 acts on the check ball 13, whereby the plunger 6 is pushed out and the pad 9 is pushed against the chain to adjust the tension of the chain. After adjusting the tension of the chain in this way, a rack 14 is formed on the surface of the plunger 9 in order to keep the tension of the chain constant when the hydraulic pressure is OFF. A ratchet 16 is movably supported so as to hold the amount of protrusion of the plunger 6. Reference numeral 17 elastically regulates the rotation of the ratchet 16, and elastically supports the pressing force of the pad 9 against the chain together with the elastic force of the spring 11.

In the present embodiment, as shown in FIGS. 1 and 2, the projection 18 is provided on the side surface of the end of the pad 9. In this embodiment, the projections 18 are provided on both side surfaces of the pad 9, but the projections 18 may be provided on either one of the side surfaces of the pad 9. Further, as shown in FIG. 2, the height of the protrusion 18 is a face (hereinafter referred to as a pad facing face) 7 facing the side surface of the pad 9 provided with the protrusion 18, for example, as shown in FIG. The height is such that the projection 18 abuts on the surface 7 of the cylinder head (pad facing surface) which is the mounting surface of the driven sprocket 2, and the projection 19 is formed on the pad facing surface 7 so as to sandwich the projection 18 therebetween. Has been done. One protrusion 19 may be provided at a position where the protrusion 18 contacts.

The operation of the present embodiment thus constructed will be described below. As shown in FIGS. 4 and 5, when the chain 3 is moved under tension by the pad 9, a slight inclination of the sprocket or a shift of the chain line due to a sprocket mounting error or the like, or the chain 3 Due to the vibration, the pad 9 is swung in the directions of the arrow (a) and the arrow (b), but since the projection 18 is provided on the side surface of the end portion of the pad 9, the swing in the direction of the arrow (a) is prevented. Restrained by the contact between the protrusion 18 and the protrusion 19,
Further, the swing in the arrow (B) direction is restrained by the contact between the projection 18 and the pad facing surface 7, and the swing of the pad 9 can be minimized.

As described above, by minimizing the swing of the pad 9, the rotation and twist of the plunger 6 are also minimized, and the engagement between the rack 14 and the ratchet 16 becomes normal, and the rack 14 and It becomes possible to reduce uneven wear of the ratchet 16.

[0015]

As described above in detail, according to the present invention, a projection is provided on the end side surface of the pad pushed out by the plunger, and the tip of this projection is brought into contact with the pad facing surface, and the pad facing surface is provided. Since it also comes into contact with the provided protrusion, the swing of the pad can be minimized, uneven wear of the ratchet and the rack can be reduced, and the life of the chain tensioner can be greatly extended.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention in a partially longitudinal section.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing a usage state of the present embodiment.

FIG. 4 is a partially enlarged view showing a usage state of the present embodiment.

5 is a view as seen from the direction of arrow X in FIG.

FIG. 6 is a diagram showing a usage mode of a conventional chain tensioner.

FIG. 7 is a front view showing a part of a conventional example in a vertical cross section.

[Explanation of sign]

 4 Chain tensioner 5 Body 6 Plunger 7 Pad facing surface 9 Pad 18 Protrusion 19 Protrusion

Claims (1)

[Claims] 1. A chain tensioner in which a chain pushed around a sprocket is pushed by a pad pushed out by a plunger to eliminate looseness of the chain, and a projection is provided on an end side surface of the pad, and the height of the projection is set to the pad. A structure of a chain tensioner characterized in that the height is such that it comes into contact with the facing surface, and another projection that comes into contact with the projection is provided on the pad facing surface.