JPH0276956A - Tensioner - Google Patents

Abstract

PURPOSE:To prevent direct contact of a rotor with a casing and facilitate the manufacturing of a supporting member itself by forming the supporting member having a projection which is engaged with the casing to stop whirling, between the rotor and the casing on the external face of a bottomed cylindrical body which consists of both a cylindrical part externally inserted in the base end part of the rotor and a bottom part which closes the end face of the base end part. CONSTITUTION:A supporting member 82 which supports the revolution of a rotor 30 is located between the rotor 30 and a casing 20, and the projection 82d of the supporting member 82 is mounted on the casing 20 as that the projection is engaged with the casing 20 to inhibit the revolution of the supporting member 82. The revolution of the rotor 30 inhibits wear of the casing 20 and the supporting member 82 is manufactured precisely so that the revolution of the rotor 30 may be supported stably.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tensioner that applies a constant tension to a chain or timing belt that drives the camshaft of the engine of a two-wheel vehicle or a four-wheel vehicle. .

[Prior Art] Tensioners such as chain tensioners and belt tensioners are used to press the chain or belt in a certain direction to maintain a certain tension when the chain or belt becomes loose due to stretching or abrasion during use. is used to maintain the

A conventional example of this tensioner is shown in FIG. 7. The tensioner is rotatably inserted into a casing 1 in which an axial cavity 1a is formed and a base side (right end side in FIG. 7) of the casing 1. a rotating body 2 in the shape of a shaft, and a rotating body 2
a pressing body 3 that is screwed onto the tip of the casing 1; one end 4a of the rotating body 2 is inserted into the engagement groove 28 of the rotating body 2; The main parts are constituted by a torsion coil spring 4 that is inserted into the rotary body 2 and applies rotational force to the rotating body 2, and a seal bolt 6 that is screwed into the base end of the casing 1 via an O-ring 5. A cap 8 made of an elastic body is fixed to the tip of the pressing body 3 by a spring pin 7, and this cap 8 comes into contact with a chain, belt, etc. and presses the chain or belt to maintain a constant tension. be done. Further, the pressing body 3 has a substantially oval outer periphery, and is inserted into a bearing 9 in which a bearing hole of the same shape is formed to restrict its rotation. This is converted into a propulsive force, and the pressing body 3 moves out of the casing.

In such a tensioner, the rotation of the rotating body 2 for propelling the pressing body 3 is an important movement element, and the support recess 1 rotatably supports the base end of the rotating body 2.
c is formed inside the casing 1. The supporting recess IC is formed so that the inner diameter thereof is the same as the outer diameter of the rotating body 2 so that the rotating body 2 can be stably operated with little vibration, and is machined with high precision. There is.

"Problems to be Solved by the Invention" However, since the four supporting parts 1c are installed in locations that are difficult to machine, it requires a great deal of effort and skill to precisely machine the four supporting parts 1c into the casing 1. Moreover, even with precision machining, it is difficult to smoothly rotate and stably support the rotating body, making it impossible to provide good rotational support for the rotating body. The concave portion 1c is prone to wear, and this wear weakens the supporting force of the rotating body, causing problems such as rattling and vibration during rotation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tensioner that does not require highly precise machining of the support recess and can stably support the rotation of a rotating body.

[Means for Solving the Problems] The present invention provides a system in which a rotating body biased to rotate by a spring and a pressing body whose rotation is restrained by a bearing are inserted into a casing in a screwed state, and the rotational force of the rotating body is In a device for converting force into a propulsive force in the axial direction of a pressing body, on the outer periphery of the cylinder part of a bottomed cylinder consisting of a cylinder part fitted onto the base end of the rotating body and a bottom part covering the end face of the base end part. A support member having a protrusion that engages with the casing to prevent rotation is provided between the rotating body and the casing, and rotatably supports the rotating body.

The protrusion of the support member may be formed into an elongated shape whose bottom side is tapered in a direction perpendicular to the outer periphery of the cylindrical portion.

[Function] In the above configuration, the support member interposed between the rotating body and the casing stably instructs the rotation of the rotating body without co-rotating with the rotating body, and also provides direct contact between the rotating body and the casing. It is designed to prevent contact. Further, since the support member is constructed as one piece, the support member itself can be easily machined and finished with high precision machining.

Further, by forming the protrusion of the support member into an elongated shape tapered at the bottom side, the protrusion bites into the casing when the support member is press-fitted into the casing, thereby preventing the support member from rotating.

[Embodiment] FIGS. 1, 2, and 3 show the overall configuration of an embodiment of the present invention. The tensioner includes a casing 20 in which an axial cavity 21 is formed, a rotating body 30 and a pressing body 40 that are screwed into the cavity 21 of the casing 20.
A spring (torsion spring) 50 that applies rotational force to the rotating body 30, a bearing 60 that is attached to the tip of the casing 20 (the left end in FIG. 1) and restricts the rotation of the pressing body 40, and the casing 20 and the pressing It is provided with a bellows 70 which can be expanded and contracted to cover the space between the body 40 and the body 40.

The casing 20 is to be attached to equipment such as an engine (not shown), and a mounting hole 22 for this purpose is formed in the outer part. Further, a seal bolt 80 is screwed into the base end (the right end in FIG. 1) via a packing 81 to maintain airtightness on the base end side.

The rotating body 30 is rotatably supported within the casing 20. The rotating body 30 is formed by connecting a male threaded portion 31 on the distal end side and a shaft portion 32 on the proximal end side. A pressing body 40 is screwed onto the portion 31 to transmit rotational force. Further, the shaft portion 32 is supported within the support recess 23 of the casing 20 for rotational support. In this case, a bottomed cylindrical support member 82 is provided between the shaft portion 32 and the support recess 23 of the casing.

The structure of this support member 82 is shown in FIG. Support member 82
The entire body is made of rigid material and is formed into a cylinder with a bottom. That is, the cylindrical portion 82b is arranged in a row so as to rise from the bottom portion 82a. The outer diameter of the cylindrical portion 82b is formed to a size that allows it to be fitted into the support recess 23 of the casing 20, and the inner diameter of the cylindrical portion 82b is sized such that the base end portion of the shaft portion 32 of the rotating body 30 is rotatably fitted. It is molded into

A protrusion 82d is provided on the outer periphery of the cylindrical portion 82b. The protrusion 82d is formed on the outside of the cylindrical portion 82b so as to be elongated in the vertical direction from the upper edge of the cylindrical portion 82b downward (towards the bottom 82a) and tapered downward.

Therefore, when the support member 82 is press-fitted into the recess 23 of the casing, the protrusion 82d bites into the inner circumferential wall of the recess 23, thereby reliably preventing the support member 82 from rotating. As described above, since the projection 82d is formed to prevent the support member 82 from rotating, at least one projection 82d may be formed.

Note that an escape hole 82c is provided in the center of the bottom portion 82a, which is used for assembling the tensioner, tightening the spring 50, and the like. Such a support member 82 supports the casing 2
0, and the shaft portion 32 of the rotary body 30 is inserted into the cylindrical portion 82b. That is, the support member 82 is interposed between the support recess 23 of the casing 20 and the shaft end of the rotating body 30 to prevent the rotating body 30 from coming into direct contact with the casing 20 and to prevent the rotating body 30 from directly contacting the casing 20. Since the casing 20 does not wear out, stable rotational support can be achieved, and since the casing 20 can be made of a lightweight material such as aluminum, its alloy, or synthetic resin, it can be made lighter. Also,
The cylindrical portion 82b of the support member 82 extends so as to cover the outer surface of the shaft portion 32 of the rotating body 30, and the supporting force is increased, so that even more stable rotational support can be performed. Furthermore, the support member 82 is a separate and independent component from the casing 20 and the rotating body 30, so it is easy to machine only this member, and the simple structure facilitates precision machining! Therefore, there is an advantage that high-precision machining suitable for stable rotation of the rotating body 30 can be easily performed. Incidentally, an axial split slit 33 is formed in the shaft portion 32 of the rotary body 30, and as will be described later, the rotary body 30 is engaged with a spring 50 to be biased to rotate.

The pressing body 40 includes a vibrator 42 having a female thread 41 formed on its inner surface, and a bushing shaft 43 fitted to the tip of the vibrator 42 .

The vibrator 42 is screwed into the male threaded portion 31 of the rotating body 30 to transmit the rotational force of the rotating body 30, and is also inserted into the bearing 60 in a rotationally restrained state to convert the rotational force of the rotating body 30 into propulsive force. It is something. On the other hand, the tip of the bushing shaft 43 extends outward from the casing 20, and the tip surface comes into contact with a chain, belt, etc. directly or via a roller that presses them. This maintains the tension of the chain belt, etc.

The spring 50 is connected to such a pressing body 40 and the rotating body 30.
has been extrapolated to This spring 50 is fitted onto the pressing body 40 and the rotating body 30 when they are in a screwed state, and the extrapolated portion extends from the inside to the outside of the rotating body 30.
, a pressing body 4o, and a spring 50.

Such a triple structure has the advantage that a sufficient stroke of the pressing body 40 can be ensured even if the length of the device in the advancing and retracting directions of the pressing body 4o is shortened. Here, one end 51 of the spring 50 is bent into an oval shape to engage with the casing 20, and the other end 52 is formed into a split slit 33 of the rotating body 30.
The rotor 30 is inserted into the rotor 30 to engage with the rotating body 30. Therefore, when the seal bolt 80 is removed, the casing 2
Insert a screwdriver etc. into the split slit 33 from the outside of the
When the rotating body 30 is rotated, rotational energy can be stored in the spring 50. Note that the end 52 of the spring 5° on the rotating body side is bent in the radial direction of the rotating body 30 after being inserted into the split slit 33 of the rotating body 30, and this bending allows the spring 50 to
The above-mentioned radial displacement of the spring 5 can be prevented.
0 stable operation is ensured.

The bearing 6o restricts the rotation of the pressing body 40, and is prevented from being pulled out by the circlip 61 so that the casing 20
Attached to the tip of the FIGS. 4 and 5 show the bearing 60 and its mounting structure. The bearing 60 has a bearing hole 62 formed in its central portion, and engagement pieces 63 formed at 90 degree intervals in its outer portion. Bearing hole 62
The pressing body 40 is formed into a substantially oval shape in which both sides of a circle are cut parallel to each other, and the outer shape is the same.
The rotation of the pressing body 40 is restricted by inserting the pipe portion 42 into the bearing hole 62. On the other hand, the engagement piece 63 restricts rotation against the rotational force of the rotating body 30. For this reason, the casing 2 corresponds to the engagement piece 63.
Engagement grooves 24 are formed at 90 degree intervals on the distal end surface of the 0, and the rotation is restrained by fitting the engagement pieces 63 into the engagement grooves 24. In this case, the depth of the engagement groove 24 of the casing 20 is larger than the thickness of the engagement piece 63, and the bearing 60 is attached to the casing 20.
It is installed slightly recessed from the tip.

A clip groove 25 protruding beyond the bearing 60 and into which the circlip 61 is fitted is provided on the inner surface of the casing 20.
is formed.

Furthermore, a spacer 9 is provided between the bearing 60 and the casing 20.
0 is inserted. The spacer 90 is inserted between the opposing portion of the bearing 60 and the casing 20, and in particular, the portion of the bearing 60 that corresponds to each engagement piece 63 is bent into a F-shape so as to wrap around each engagement piece 63. As a result, the engaging piece 63
and the engagement groove 24 of the casing 20. In the spacer 90 having such a structure, the wide surface of the spacer 90 prevents the pressing force of the engaging piece 63 due to the rotational force of the rotating body 30 transmitted through the pressing body 40 from directly acting on the casing 2o. Therefore, the engagement piece 63 and the casing 2
This makes it possible to prevent the end faces of the engagement grooves 24 from being worn out.

In this way, by using the spacer 90 for the bearing 60 and using the support member 82 of the rotating body 30, the casing 2
0 can be constructed using materials with poor wear resistance such as aluminum or synthetic resin, and even in this case, the tensioner can prevent wear of the casing 20 at the mounting portion of the bearing 60 and the shaft portion of the rotating body 3o. It operates without any problems and is lightweight. Note that one end 51 of the spring 5o is extracted from a part of the engagement groove 24 in the casing 20, and is intended to engage with the casing 20 described above.

Next, the bellows 70 is passed between the bush shaft 43 of the pressing body 40 and the casing 20, and covers the space between them. A protruding line 71 is formed on the inner surface of the end of the bellows 70 on the pressing body 40 side.
is fitted into a corresponding groove 44 formed on the outer surface of the bush shaft 43. The end portion on the pressing body 40 side is sealed by winding the garter spring 72 from the outside. On the other hand, the end on the casing side is connected to a cap 73 attached to the casing 20. Note that this connection can be made by any suitable means such as adhesion or welding. The cap 73 is made of a substantially cylindrical hard material with an inner diameter that is approximately equal to the outer diameter of the casing 20 on the base side and whose tip is slightly bent inward. It is attached to the casing 20 by caulking 74 at a predetermined position on the outer peripheral surface of 73. The bellows 70 is connected to a bent portion at the tip of the cap 73. Furthermore, casing 2
o A circumferential groove 26 is formed on the outer surface, and a seal ring 75 is wound around this circumferential groove 26. Seal ring 75
is made of an elastic body, and when the cap 73 is attached to the casing 20 while being wound around the circumferential groove 26, it comes into close contact with the inner surface of the cap flap and the outer surface of the casing 20, sealing the space between them. Therefore, intrusion of dust from the outside and leakage of the lubricating oil sealed inside the casing 2o are prevented.

With the structure using such a seal ring 75, the seal between the cap 73 and the casing 20 can be ensured. Therefore, when attaching the cap 73, there is no need to press-fit the cap to maintain airtightness of the part, and there is no need for a high degree of dimensional accuracy for press-fitting.Therefore, processing can be easily performed.1. Productivity is improved - In FIGS. 2 and 3, 100 is a stopper, and the tensioner is installed in front to lock the thrust of the pressing body 4o. This stopper 100 is removed after the tensioner is installed at the location where it is used.

In addition, 40a% 60a and 90a in FIG. 1 are lubricating oil circulation paths established in the pressing body 40, bearing 60, and spacer 90, respectively, and these circulation paths 40a, B
The lubricating oil filled inside is circulated evenly inside the casing 20 by the oa and 90a.

[Effects of the Invention] As explained above, the present invention provides a support member for rotationally supporting the rotor between the rotor and the casing, and engages the protrusion of the support member with the casing to rotate the support member. Since the casing is assembled in a blocked state, the casing is not worn out by the rotation of the rotating body, and by precision machining of the support member, the rotation of the rotating body can be stably supported.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIGS. 2 and 3 are a plan view and a side view thereof, and FIGS. 4 and 5 are perspective views and sectional views showing a bearing mounting structure, Figure 6 (a
), (b), and (C) are sectional views, front views, and side views showing the support member, and FIG. 7 is a sectional view of a conventional example. 20...Casing, 30...Rotating body, 40...
Pressing body, 50'... Spring, 60... Bearing, 70...
-Bellows, 82...Supporting member, 82d...Protrusion.

Claims (2)

[Claims] (1) A rotating body that is rotationally biased by a spring and a pressing body whose rotation is restrained by a bearing are inserted into a casing in a screwed state, and the rotational force of the rotating body is converted into an axial propulsive force of the pressing body. In the converting device, a projection that engages with the casing to prevent rotation on the outer periphery of the cylindrical body of a bottomed cylindrical body consisting of a cylindrical part that is fitted onto the base end of the rotating body and a bottom that covers the end surface of the base end. A tensioner characterized in that a support member having a shape formed therein is provided between a rotating body and a casing, and rotatably supports the rotating body. (2) The tensioner according to claim 1, wherein the protrusion of the support member is formed into an elongated shape whose bottom side tapers in a direction perpendicular to the outer periphery of the cylindrical portion.