JPH03260442A - Tensioner - Google Patents

Abstract

PURPOSE:To prevent wear of a casing due to rotation of a rotor and accomplish a supporting member through precision processing, in which a cavity is formed in the cylindrical part of a bottom-equipped cylinder, by locating the supporting member between the casing and rotor. CONSTITUTION:The shank 32 of a rotor 30 is borne by a casing 20 at its recess 23 to make rotary supporting. A supporting member 82 in the form of a bottom- equipped cylinder is installed between these shank 32 and recess 23. The bottom part 82a is conjugate with the cylindrical part 82b, which is provided with a slit 82d. Because of being formed continuously from the upper edge of this cylindrical part 82b to the lower edge, in which part of the recess 23 in the casing 20 is fitted, the supporting member 82 is checked from turning certainly. Thereby the supporting member 82 is prevented from turning together with the rotor 30, which prevents the casing 20 from wear, and the supporting member 82 can be accomplished with precision.

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. The tensioner includes a casing 1 in which an axial cavity 1a is formed, a shaft-shaped rotating body 2 rotatably inserted into the base side (right end side in FIG. 8) of the casing 1, 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 is fixed to the tip of the pressing body 3 by a spring pin 7, and the cap 8 comes into contact with a chain, belt, etc., and is pressed so that the chain or belt maintains a constant tension. 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 1c is formed so that its inner diameter is the same as the outer diameter of the rotating body 2, and is machined with high precision so that the rotating body 2 can be stably operated with little vibration. .

"Problem to be Solved by the Invention" However, since the support recess 1c is provided in a location that is difficult to process, it requires a great deal of effort and skill to precisely process the support recess IC 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 the axial direction of the suppressing body, 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 support member having a space into which a part of the casing fits and prevents rotation is provided between the rotating body and the casing, and rotatably supports the rotating body.

The space of the support member may be a slit or a groove formed in a direction perpendicular to the outer periphery of the cylindrical portion.

Further, the space of the support member may be a through hole into which a part of the casing is inserted during insert molding of the casing incorporating the support member.

[Operation] In the above configuration, the support member interposed between the rotating body and the casing stably directs 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.

Furthermore, when the space in the support member is a slit or groove, not only is the support member prevented from rotating by engagement with a protrusion formed on the casing, but the support member is also prevented from rotating as in the case where the space is a through hole. Rotation can also be prevented by fitting a portion of the casing during insert molding of the casing incorporating the casing.

[Embodiment] FIG. 1, FIG. 2, and FIG. 3 show the overall configuration of an embodiment of the present invention. a rotating body 30 and a pressing body 40 which are inserted in a screwed state;
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 suppressor 40 is screwed onto the portion 31 to transmit rotational force, and 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

The cylindrical portion 82b has slits 82 at 90° intervals on the outer circumference.
d is provided. This slit 82d is the cylindrical portion 82b.
It is formed continuously from the upper edge to the lower edge. Therefore, the support member 82 is formed by fitting a part of the recess 23 of the casing into the slit 82d.
2 is reliably prevented from rotating. As described above, since the slit 82d is formed to prevent the support member 82 from rotating, at least one slit 82d may be formed.

Partial fitting of the casing into the slit 82d of the support member 82 is the casing 20 with the support member 82 incorporated into the mold.
This is done simultaneously with casing molding during insert molding. Partial fitting of the casing into the slit 82d is not limited to the method described above, but the slit 82d may be fitted into a projection (not shown) previously formed on the inner wall of the recess 23 of the casing. It may be a vertical groove.

A support member 821 shown in FIG. 7 is a modified example of the support member, and has the same external shape as the support member 82, with a bottomed cylindrical shape, and a through hole 821d is provided in the cylindrical portion instead of the slit 82d of the support member 82. 821b. This support member 821 is incorporated into a mold, and when insert molding the casing 20, a part of the casing fits into the through hole 821d and is integrated with the casing 20, thereby preventing rotation.

Note that an escape hole 82c (821c), which is used for assembling the tensioner, tightening the spring 50, etc., is provided in the center of the bottom portion 82a (821a). Such a support member 82 (821) is fitted into the support recess 23 of the casing 20, and the shaft portion 32 of the rotating body 30 is inserted into the cylindrical portion 82b (82lb). That is, the support member 82 (821) is interposed between the support recess 23 of the casing 20 and the shaft end of the rotating body 30, preventing the rotating body 30 from directly contacting the casing 20, and preventing the rotation of the rotating body. Since the casing 20 is not worn out by the casing 20, stable rotational support can be achieved, and the casing 20 can be made of lightweight material such as aluminum, its alloy, or synthetic resin, making it possible to reduce the weight. . In addition, the cylindrical portion 82b (821) of the support member 82 (821)
21b) 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, and it is easy to machine only this, 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 pipe portion 42 having a female threaded portion 41 formed on its inner surface, and a bushing shaft 43 fitted to the tip of the pipe portion 42 .

The pipe portion 42 is screwed into the male threaded portion 31 of the rotating body 30 to transmit the rotational force of the rotating body 3o, 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 tension in chains, belts, 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 40 and a spring 50.

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 inserted into the split slit 33 of the rotating body 30 to engage with the rotating body 30. Engagement is attempted. Therefore, when a tribar or the like is inserted into the split slit 33 from the outside of the casing 20 with the seal bolt 80 removed and the rotating body 30 is rotated, rotational energy can be stored in the spring 50.

The bearing 60 restricts the rotation of the pressing body 40, and is prevented from being pulled out by the circlip 61 so that the casing 2o
Attached to the tip of the FIGS. 4 and 5 show the structure of this bearing 60 and its installation. The bearing 60 has a bearing hole 62 formed in the center part, and retaining pieces 63 formed at 90 degree intervals in the outer part. ing. 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 suppressor 40 is restrained by inserting the pipe portion 42 into the bearing hole 62. On the other hand, the engagement piece 63 resists the rotational force of the rotating body 30 and performs rotational restraint. 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 corresponding to each engaging piece 63 is bent into a U-shape so as to wrap around each retaining 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 retaining piece 63 due to the rotational force of the rotating body 30 transmitted through the pressing body 40 from directly acting on the casing 20. 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 a material 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 30. It operates without any problems and is lightweight. In addition, one end 51 of the spring 50 is extracted from a part of the engagement groove 24 in the casing 20 to be engaged 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 whose base side has an inner diameter approximately equal to the outer diameter of the casing 20 and whose tip is slightly bent inward. It is attached to the casing 20 by caulking 74 a predetermined position on the outer peripheral surface of the casing 20 . The bellows 7° is connected to a bent portion at the tip of the cap 73. Furthermore, casing 2
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, the cap 73
It comes into close contact with the inner surface and the outer surface of the casing 20 to seal the space between them. Therefore, intrusion of dust from the outside and leakage of the lubricating oil sealed inside the casing 20 are prevented.

With the structure using such a seal ring 75, airtightness between the cap 73 and the casing 20 can be ensured.

In FIGS. 2 and 3, 100 is a stopper that locks the pushing body 40 in front of the tensioner assembly. 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 the pressing bodies 40. Bearing 60. and a lubricating oil circulation path established in the spacer 90, and these circulation paths 40a, 60a, and 90a transfer the lubricating oil filled inside to the casing 20.
It is designed to circulate evenly inside.

[Effects of the Invention] As explained above, the present invention provides a support member for rotationally supporting the rotary body between the rotary body and the casing, and a part of the casing fits into the space of the support member so that the support member Since the casing is attached to the casing in a rotation-preventing state, the casing does not wear out due to the rotation of the rotating body, and by precision machining of the support member, it is possible to stably support the rotation of the rotating body. .

[Brief explanation of drawings]

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, FIG. 6 shows the support member, FIG. 6(a) is a plan view, and FIG. 6(b) is a
), FIG. 7 shows another support member, FIG. 7(a) is a plan view, FIG. It is a sectional view of a conventional example. 20...Casing, 30...Rotating body, 40...
Pressing body, 50... Spring, 60... Bearing, 70...
・Bellows, 82.821...Supporting member, 82d...
- Slit (space), 821d... through hole (space). (CL) DingOO 7 (a) Ryo 4 Rusuke 5 questions

Claims (3)

[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 portion of the casing is fitted into a cylindrical portion of a bottomed cylindrical body consisting of a cylindrical portion that is fitted onto the base end of the rotating body and a bottom portion that covers an end surface of the base end to prevent rotation. A tensioner characterized in that a support member having a space is provided between a rotating body and a casing, and rotatably supports the rotating body. (2) The tensioner according to claim (1), wherein the space in the support member is a slit or groove formed in a direction perpendicular to the outer periphery of the cylindrical portion. (3) The tensioner according to claim (1), wherein the space of the support member is a through hole into which a part of the casing is inserted during insert molding of the casing incorporating the support member.