JPH03260441A - Tensioner - Google Patents

Abstract

PURPOSE:To prevent wear of a casing and accomplish a high precision supporting member by covering the inner bottom surface of casing at its cavity part with a flange part, and providing the supporting member, with which part of the casing is fitted in a detent recess, between a rotor and the casing. CONSTITUTION:The shank 32 of a rotor 30 is borne by a casing 20 at its recess 23 to make rotary supporting. Between the shank 32 and the recess 23, a supporting member 82 in the form of a bottom-equipped cylinder is installed, which has a flange part 82d at the opening and is conjugate with the bottom part 82a and cylindrical part 82b, wherein the flange part 82d is covering the bottom surface 27 of a cavity 21. A detent recess 82e is formed at the periphery of the flange part 82d, in which part of the casing 20 is fitted, and thereby the supporting member 82 is checked from turning. Thus the casing is prevented from wear, and the supporting member can be formed with high accuracy becaused of being formed separately.

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 rotating body 2, one end 4a of which is inserted into the retaining groove 28 of the rotating body 2, and the other end 4b of which is inserted into the long groove 1b on the tip side of the casing l; 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 I rotatably supports the base end of the rotating body 2.
C is formed by cutting through the bottom surface 1d of 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. .

"Problems to be Solved by the Invention" However, since the support recess 1c is provided in a location that is difficult to machine, it requires a great deal of effort and skill to precisely machine the support recess IC inside the casing l. 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 easily worn, and this wear weakens the supporting force of the rotating body, causing problems such as rattling and vibration during rotation.

In addition, the base end surface of the torsion coil spring 4 comes into contact with the bottom surface 1d of the casing 1, causing abrasion damage to the bottom surface 1d, and causing support recess 1C.
There was a problem in that the supporting force of the casing 1 was reduced and the strength of the casing 1 itself was reduced, resulting in a shortened lifespan of the tensioner.

Therefore, the present invention provides a tensioner that does not require highly precise machining of the support recess, eliminates wear on the casing due to contact with the torsion coil spring, and is capable of stably supporting the rotation of the rotating body. The purpose is to

[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 device for converting the force into a propulsive force in the axial direction of the suppressing body, the bottomed cylindrical body includes a cylindrical part that is fitted onto the base end of the rotating body, and a bottom part that covers the end face of the base end, A supporting member is provided with a flange portion that covers the bottom surface of the casing on the outer periphery of the opening of the cylindrical portion, and has an engaging recessed portion in which a part of the casing fits into the outer periphery of the flange portion to prevent rotation. It is characterized in that it is provided in the rotor and rotatably supports the rotating body.

The bottomed cylindrical body of the support member may be formed from a cylindrical tube portion and a disc-shaped bottom portion formed separately from the tube portion.

[Operation unit] 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 supports the rotating body, the casing, and the torsion coil spring. Direct contact between the support member and the bottom surface of the casing is prevented.6 Furthermore, since the support member is constructed as a single component, the support member itself can be easily machined and finished with high precision machining.

In addition, when the bottomed cylindrical body of the support member is formed from a cylindrical tube part and a disc-shaped bottom part formed separately from this cylindrical part, the corner of the bottom part of the bottomed cylindrical body (boundary part) becomes an accurate right angle, resulting in a highly accurate bottomed cylindrical body.

[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. This support recess 23 is formed by cutting through the bottom surface 27 of the cavity 21 of the casing. In this case, a support member 82 in the form of a bottomed cylinder having a flange portion at the opening 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 continuous manner so as to stand up from the bottom portion 82a, and the flange portion 8 is provided on the outer periphery of the opening of the cylindrical portion 82b.
2cl are installed in series. 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 formed to fit into the shaft portion 32 of the rotating body 30.
The proximal end portions of the two are molded to a size that allows them to be rotatably fitted together. Further, the flange portion 82d is formed so that its outer diameter substantially matches the inner diameter of the cavity portion 21, and covers the bottom surface 27 of the cavity portion 21 after being installed in the casing 20.

Engagement recesses 82e are provided on the outer periphery of the flange portion 82d at intervals of 90'. By fitting a part of the casing 20 into the engagement recess 82e, the support member 8
2 is designed to prevent rotation. Partial fitting of the casing 20 into the engagement recess 82e is not only carried out simultaneously with casing molding during insert molding of the casing 20 with the support member 82 incorporated into the mold, but also a portion of the casing 20 that is formed in the inner wall of the cavity 21 is Engagement recess 82e in a protrusion (not shown)
This supporting member 82 is a separate and independent part from the casing 20 and the rotating body 30, and it is easy to machine only this member, and the structure is simple, so precision machining is not required. It's easy. Therefore, there is an advantage that high-precision machining suitable for stable rotation of the rotating body 30 can be easily performed. As described above, since the engagement recess 82e is formed to prevent the support member 82 from rotating, at least one engagement recess 82e may be formed.

The support member 821 shown in FIG. 7 is a modified example of the support member, and has the same outer shape as the support member 82, which is a cylindrical shape with a bottom.
It is formed by combining a.

That is, the cylindrical portion 821b is a cylindrical body with a flange portion 821d formed on one end side, and a 90 mm
U-shaped grooves (opening downward in the drawing) A at intervals of ℃
is formed.

On the other hand, the bottom portion 821a is formed into a disk having an outer diameter approximately equal to the inner diameter of the cylindrical body of the cylindrical portion 821b, and a protrusion B that fits into the U-shaped groove A is formed on the outer periphery of this disk. In this way, the cylinder part 821b and the bottom part 821a are formed separately, and the bottom part 821a is formed in the U-shaped groove A of the cylinder part 821b.
The support member 821 is formed by fitting the protrusion B of the support member 821 to connect the bottom portion 821a to the cylindrical portion 821b. The support member 821 formed in this way is attached to the bottom 82 of the bottomed cylindrical body.
The corner C of 1a becomes an accurate right angle, and a highly accurate bottomed cylindrical body is obtained without requiring any special machining. Similar to the support member 82 described above, this support member 821 is inserted into the engagement recess 821e formed in the flange portion 821d.
A part of 0 is inserted to prevent 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). In such a support member 82 (821), the flange portion 82d covers the bottom surface 27 of the cavity 21, and the cylindrical portion 82b (821b) is fitted into the support recess 23 of the casing 2Q. The shaft portion 32 of the rotary body 30 is inserted into. That is, the support member 82 (821) is interposed between the bottom surface 27 and the support recess 23 of the casing 20 and the shaft ends of the spring 50 and the rotating body 30, so that the spring 50 and the rotating body 30 directly contact the casing 20. Since the bottom surface 27 and the support recess 23 of the casing 20 are prevented from being worn out, stable rotational support can be achieved, and the casing 20 is molded from a lightweight material such as aluminum, its alloy, or synthetic resin. This makes it possible to reduce the weight. In addition, the support member 82 (
The cylindrical portion 82b (821b) of the rotating body 30 extends 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 achieved. Incidentally, an axial split slit 33 is formed in the shaft portion 32 of the rotating body 30, and as described later, is engaged with a spring 50 to perform rotational biasing.

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 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 30, and is 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 rib 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 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 suppressor 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 serves to restrict rotation against the rotational force of the rotating body 3o. 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 2o is larger than the thickness of the engagement piece 63, and the bearing 60 is attached to the casing 2o.
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 9o 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 engagement piece 63 is bent into a U-shape so as to wrap around each engagement piece 63. As a result, the engaging piece 63
and the retaining groove 24 of the casing 20. The spacer 90 having such a structure 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 20 with the wide surface of the spacer 90. 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 70 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.

Note that 40a, 60a, and 90a in FIG. 1 are circulation paths for lubricating oil established in the pressing body 40, bearing 60, and spacer 90, respectively, and the inside is filled with these circulation paths 40a, 60a, and 90a. Casing lubricant 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 rotating body between the rotating body and the casing, and
The flange portion of the support member covers the bottom surface of the cavity inside the casing, and a portion of the casing is fitted into the engagement recess of the support member to prevent the support member from rotating. The casing does not wear out due to contact and rotation of the rotating body, and since it is molded separately from the casing, the support member itself can be molded with high precision, and can 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, 6 shows a supporting member, FIG. 6(a) is a plan view, FIG. 6(b) is a sectional view taken along line bb of FIG. 8(a) is a plan view, FIG. 8(b) is a sectional view taken along the line b--b of FIG. 8(a), FIG. 8(c) is a bottom view, and FIG. 8 is a sectional view of the conventional example. 20...Casing, 30...Rotating body, 40...
Pressing body, 50... Spring, 60... Bearing, 70...
Bellows, 82, 821...Supporting member, 82d, 82
1d...Flange portion, 82e, 821e...Engagement recess.

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 cylindrical body with a bottom is formed of a cylindrical part that is fitted over the base end of the rotating body and a bottom part that covers the end face of the base end, and the bottom face of the casing is covered on the outer periphery of the opening of the cylindrical part. A supporting member is provided between the rotating body and the casing, and has a flange portion connected thereto and an engagement recess into which a portion of the casing is fitted into the outer periphery of the flange portion to prevent rotation;
A tensioner that rotatably supports a rotating body. (2) Claim (2) wherein the bottomed cylindrical body of the support member comprises a cylindrical tube portion and a disc-shaped bottom portion formed separately from the tube portion.
Tensioner described in section 1).