JPH04300444A - Automatic tensioner - Google Patents

Abstract

PURPOSE:To dispense with thermal distortion of an arm and a plate. CONSTITUTION:Abrasion-resistant members 81, 82 are arranged on an abutting portion of a smoothing member 22, between a base 11 of an arm 10 required for abrasion resistance and a plate 31. Thermal treatment of the arm 10 and the plate 31 are dispensed with. As a result, generation of thermal distortion of the arm 10 and the plate 10 is prevented, and the arm 10 is smoothly rotated. In addition, manufacturing cost is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto tensioner that applies tension to a belt such as a drive belt of a vehicle engine.

0002

[Prior Art] As a conventional auto tensioner, one shown in FIG. 9, for example, has been disclosed.
(See Publication No. 2-2182). In the figure, the auto tensioner 1 includes an arm 3 having a base 3a rotatably attached to a cylindrical housing 2, an idler pulley 4 rotatably attached to the free end of this arm 3, and a housing 2. A torsion coil spring 5 is provided between the base 3a of the arm 3 and applies tension to the belt via an idler pulley 4. 2
and the base 3a of the arm 3 facing this outer peripheral surface.
A resin sleeve 6 is fitted into an annular space formed between the resin sleeve 6 and the inner peripheral surface.

0003

[Problems to be Solved by the Invention] In the conventional auto tensioner 1 described above, the arm 3 rotates around the resin sleeve 6, so if the resin sleeve 6 wears unevenly, the attachment to the arm 3 may become loose. occurs. This causes uneven rotation of the arm 3, which may cause the tension of the belt to fluctuate.

[0004] Therefore, in order to reduce the surface pressure of the resin sleeve 6, the resin sleeve 6 is required to be large not only in diameter but also in the axial direction. Therefore, the auto tensioner 1 has become large. Therefore, the applicant has filed a patent application
No. 260,736, an application has been filed for an auto tensioner that solves the problems of the prior art described above.

[0005] This invention is disclosed in the above-mentioned Japanese Patent Application No. 2-260736.
This is a further improvement of the auto tensioner filed in No. 1, and its purpose is to provide an auto tensioner that does not require heat treatment of the arm and plate.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the auto tensioner according to claim (1) of the present invention has the following features:
The base side of the arm is sandwiched between plates via a sliding member and pivoted to a fixed shaft, and a spring is interposed between the fixed shaft and the arm, and the biasing force of this spring causes the free end side of the arm to An auto tensioner that applies tension to a belt via an idler pulley that is pivoted on the arm, and in which wear resistance is provided to the sliding member contact portion between the base side of the arm and the plate. It is a feature.

[0007] Furthermore, the autotensioner according to claim (2) is characterized in that a wear-resistant member is disposed between the base side of the arm and the plate as the wear-resistant imparting means.

[0008]

[Operation] According to the present invention, since a wear-resistant member is placed at the contact portion of the sliding member between the base side of the arm and the plate, which requires wear resistance, heat treatment of the arm and plate is not required. can do. As a result, thermal distortion of the arm and plate can be eliminated, the arm can be rotated smoothly, and manufacturing costs can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1 is a plan view of an auto tensioner.
2 is an explanatory cross-sectional view taken along the line II-II in FIG. 1, FIG. 3 is an explanatory cross-sectional view taken along the line III-III in FIG.
5 is a plan view of the collar, FIG. 6 is a sectional view of the VI-VI in FIG. 5, FIG. 7 is a plan view of the ball receiving member, and FIG. 8 is a plan view of the collar. -VIII is an explanatory cross-sectional view taken along the arrow.

In the figure, E is an auto tensioner that applies tension to a belt (not shown) such as a drive belt of a vehicle engine, and the base 11 side of the arm 10 is
The sliding member 20 is sandwiched between the plates 30 and 31 and attached to the fixed shaft 40, and a spring 50 is interposed between the fixed shaft 40 and the arm 10, and the biasing force of the spring 50 causes the arm 10 to rotate. Tension is applied to the belt via an idler pulley 60 pivoted on the free end side.

The present invention is particularly characterized in that a wear-resistant member 80 is disposed at the contact portion of the sliding member 20 between the base 11 side of the arm 10 and the plate 31.

Next, the structure of the present invention will be explained in more detail.

The base 11 of the arm 10 is formed in a cylindrical shape and has a through hole 11a on its axis, and a concentric cup-shaped recess 11b is formed on the lower surface of the base 11 in communication with the through hole 11a. has been done. Further, on the upper surface of the base 11, three circular grooves 11c are formed at predetermined intervals, for example at the same intervals, on the outer circumference of the recess 11b concentrically with the through hole 11a. The groove 11c is set so that a small-diameter sub-ball 21, which is an outer sliding member, is loosely fitted into the groove 11c. In this embodiment, the grooves 11c are formed outside the grooves 11b, but they may be formed on the same circumference.

The fixed shaft 40 has a large diameter part 40b at the upper part and a small diameter part 40c at the lower part with the flange part 40a in between, and a threaded part 40 at the lower end of the small diameter part 40c.
d is formed. A holder plate 30 as an upper plate and a base plate 31 as a lower plate are attached to the small diameter portion 40c via a collar 81 to the flange portion 4.
The upper surface of the holder plate 30 is fixed in contact with the lower surface of the holder plate 0a. That is, the small diameter portion 40c has holes 30a and 81a formed in the holder plate 30, collar 81, and base plate 31 in this order from above.
, 31a are inserted, and by tightening a nut 42 to a screw portion 40d protruding from the base plate 31, the holder plate 30 and the base plate 31 are fixed to the fixed shaft 40 with their axial movement restricted.

Note that the fixed shaft 40 may be fixed by welding or caulking. Further, the base plate 31 is fixed to an engine mounting bracket (not shown).

The collar 81 is a wear-resistant member 80 on the base plate 31 side, and is made of a high-hardness material, and has a flange portion 81b formed at its lower end and a bulge portion 81c formed on its outer peripheral surface. Three arcuate notches 81d are formed at predetermined intervals on the outer circumferential surface of the bulging portion 81c, for example, at the same interval, and communicate with the upper surface of the flange portion 81b, and the radius of curvature of the notches 81d is as follows. The radius is set to be at least equal to or larger than the radius of the large-diameter main ball 22 that is the inner sliding member.

The arm 10 is placed in the recess 11b of the arm 10.
A cup-shaped ball receiving member 82 made of a high-hardness material, which is a wear-resistant member 80 on the side, is fitted, and a hole 82a having the same diameter and concentric with the through-hole 11a of the arm 10 is formed in the bottom surface of the cup-shaped ball receiving member 82. ing. The main ball 22 is arranged so as to be in contact with the inner circumferential surface of the ball receiving member 82, the notch 81d of the collar 81, and the upper surface of the flange portion 81b.

Note that a material with high lubricity may be used as the wear-resistant member 80. Further, as a means for imparting wear resistance, a highly lubricating material may be directly coated on the concave groove 11c of the arm 10. In this case, the ball receiving member 82
can be deleted.

Each groove 11c of the arm 10 is provided with a disc-shaped elastic member 7 made of rubber or the like, which is an example of a biasing means.
0 is embedded, and a seat plate 71 is installed on the upper surface of this elastic member 70.
The sub-ball 21 is placed through the groove 11c with a portion thereof protruding from the groove 11c. Note that the elastic member 70 is not limited to the above embodiment, and for example, a disc spring or the like may be used. Further, the elastic member 70 is attached to the base 11 of the arm 10.
It may be provided on the holder plate 30 side instead of on the side.

Base 11 of arm 10 and base plate 3
An X ring 90 made of an elastic material is arranged between the circumferential surfaces facing each other to seal the circumferential surfaces.
The arm 10 side of the ring 90 is vulcanized and bonded to the base 11 of the arm 10. The X-ring 90 prevents the grease filled in the space formed by the base 11 of the arm 10, the holder plate 30, and the base plate 31 from leaking to the outside. Also,
The X-ring 90 has a function of preventing dust from entering from the outside.

The base 50a of the spiral spring 50, which is an example of a spring, is inserted into a cut groove 40e formed at the upper end of the fixed shaft 40, and the upper edge of the cut groove 40e can be caulked. by spiral spring 50
from falling off from the fixed shaft 40. Further, the free end 50b of the spiral spring 50 is connected to the base 1 of the arm 10.
It is locked to a locking shaft 51 that is integrally provided near 1.

Note that the spring 50 may be a conventional torsion coil spring.

Next, the operation of the embodiment of the present invention will be explained.

In FIG. 2, in response to the axial input F1 acting on the idler pulley 60, the cooperative action of each sub-ball 21 and holder plate 30, each main ball 22, collar 81, and ball receiving member 82 is applied. This can be handled by Also idler pulley 6
For radial inputs F2 and F3 acting on 0,
This can be achieved by the cooperative action of each main ball 22, collar 81, and ball receiving member 82.

Further, the sub-ball 21 is pressed against the lower surface of the holder plate 30 by the elastic force of the elastic member 70, and the X-ring 90 is elastically pressed against the base plate 31. As a result, variations in the dimensions of the base 11 of the arm 10, the holder plate 30, and the base plate 31 in the axial direction can be reduced by the elastic member 70 and the X-ring 90.
In particular, this can be absorbed by the elastic member 70, and the mounting play in the axial direction on the base 11 side of the arm 10 can be eliminated.

Here, the rotation of the arm 10 is performed while rotating each main ball 22 around the fixed shaft 40, and the collar 81 and ball receiving member 82 that rotatably support each main ball 22 are High surface pressure is applied. However, since the collar 81 and the ball receiving member 82 are made of a highly hard material and have high wear resistance, wear can be prevented.

[0028] This makes it unnecessary to heat treat the arm 10 and base plate 31, and eliminates the occurrence of thermal strain. As a result, the arm 10 can be rotated smoothly and manufacturing costs can be reduced.

[0029]

Effects of the Invention As described above, according to the present invention, a wear-resistant member is disposed at the sliding member contact portion between the base side of the arm and the plate, which requires wear resistance. Heat treatment of the plate can be made unnecessary. As a result, thermal distortion of the arm and plate can be eliminated, the arm can be rotated smoothly, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view of an auto tensioner according to an embodiment of the invention.

FIG. 2 is an explanatory cross-sectional view taken along the line II-II in FIG. 1;

FIG. 3 is an explanatory cross-sectional view taken along the line III-III in FIG. 1;

FIG. 4 is an explanatory cross-sectional diagram taken along the line IV-IV in FIG. 1;

FIG. 5 is an explanatory plan view of a collar according to an embodiment of the invention.

FIG. 6 is an explanatory cross-sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is an explanatory plan view of a ball receiving member according to an embodiment of the invention.

FIG. 8 is an explanatory cross-sectional view taken along the line VIII-VIII in FIG. 7;

FIG. 9 is an explanatory cross-sectional view of an auto tensioner according to a conventional example.

[Explanation of symbols]

E Auto tensioner 10 Arm 11 Base 20 Sliding member 21 Sub ball (outer sliding member) 22 Main ball (inner sliding member) 30 Plate (holder plate) 31 Plate (base plate) 40 Fixed shaft 50 Spring (spiral spring) 60 Idler pulley 70 Biasing means (elastic member) 80 Wear-resistant member (ball receiving member) 81 Collar (base plate side wear-resistant member) 82 Ball receiving member (arm side wear-resistant member) 90 X-ring

Claims (2)

[Claims] Claim 1: The base side of the arm is held between plates via a sliding member and is pivoted to a fixed shaft, and a spring is interposed between the fixed shaft and the arm, and the biasing force of the spring causes the arm to move. The auto tensioner is configured to apply tension to the belt via an idler pulley pivoted on the free end side of the arm, and the sliding member contact portion between the base side of the arm and the plate has a wear-resistant An auto tensioner characterized by being given the following. 2. The auto tensioner according to claim 1, wherein a wear-resistant member is disposed between the base side of the arm and the plate as the wear-resistant imparting means.