JP2558719Y2 - Friction type auto tensioner - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto tensioner for applying a predetermined tension to a V-belt or the like used for driving an auxiliary machine of an automobile.

[0002]

2. Description of the Related Art As this type of auto tensioner, FIG.
The following are known. In the description of FIG. 4, the left and right of the drawing are left and right.

[0003] In FIG. 4, a first portion of a fixed portion of an engine (for example, an engine block or the like) (1)
The fixing member (2) is fixed. This member (2) is formed by forming a cylindrical portion (2b) on the left side surface of a perforated disk portion (2a), and a portion of the disk portion (2a) outside the cylindrical portion (2b) is a bolt.
It is fixed to the fixed part (1) by (3). A cylindrical second fixing member is inserted into the center hole of the disk portion (2a) of the first fixing member (2).
The right end of (4) is fitted, and a part of the left side protrudes from the left end of the first fixing member cylindrical portion (2b).

A movable member (5) is provided around the second fixed member (4).
Are rotatably mounted. The movable member (5) has a thick cylindrical portion (5a) and an outward flange (5b) formed at the left end thereof.
And, a short cylindrical portion (5c) formed rightward from the outer periphery of the flange portion (5b), and a bracket portion (5d) formed radially outward from a part of the short cylindrical portion (5c). And an idler (tension pulley) (6) at the tip of the bracket (5d).
Are rotatably mounted. Movable member thick cylindrical part (5
a) is rotatably fitted around the second fixing member (4). The stopper (7) is a bolt on the left end face of the second fixing member (4).
Are fixed (8), a ring-shaped sliding member which is fitted to the left end surface of the movable member (5) (9) is sandwiched between the stopper (7). A plurality of spring receiving holes (10) are formed on the right end surface of the movable member thick cylindrical portion (5a), and a block-shaped friction material (11) is slidable at the right open end of these holes (10). Compression coil spring between the bottom of the hole (10) and the friction material (11)
(12) is fitted. The block-shaped friction member (11) is pressed against the first fixed member disc portion (2a) by the spring (12), and the left end surface of the movable member (5) is a ring-shaped sliding member. It is pressed against the stopper (7) via (9).

The right end of the movable member thick cylindrical portion (5a) fits with a gap inside the first fixed member cylindrical portion (2b), and the left end of the first fixed member cylindrical portion (2b) and the movable member short cylinder The right end of the part (5c) is close. A torsion coil spring (13) is fitted inside the cylindrical portions (2b) and (5c) and in an annular space around the movable member thick-walled cylindrical portion (5a). This spring
(13) has one end on the first fixed member (2) and the other end on the movable member.
The movable member (5) is urged in a direction in which the idler (6) is pressed against a belt (not shown).

When excessive tension is applied from the belt, the movable member (5) rotates in a direction in which the idler (6) moves away from the belt, and when the belt becomes loose, the idler (6) is rotated by the spring (13).
The movable member (5) rotates in the pushing direction in which (6) is pressed against the belt. In any case, a damping force is given to the rotation of the movable member (5) by the friction material (11) , and a damper effect is exerted.

[0007]

[Problem to be Solved by the Invention] In the case of the conventional friction type auto tensioner as described above, even when the idler (6) is separated from the belt due to excessive tension from the belt, the belt is loosened and the idler (6) is moved to the belt. Since the damping force is the same at the time of pushing in to follow the following, there is the following problem.

If the damping force is reduced so that the idler (6) follows the belt at an appropriate level, the damping force is insufficient when the tension fluctuation from the belt is large, and the vibration of the idler (6) is reduced. Becomes large and the tension cannot be controlled.
Belt noise is generated. Also, if the damping force is increased to withstand excessive tension, the idler (6) will delay following the belt when the belt is loose, and the belt will remain loose especially when the tension fluctuation is large. Then, belt slip noise is generated.

The purpose of this invention is to solve the above problems,
An object of the present invention is to provide a compact friction type auto-tensioner that can quickly follow the belt slack and has sufficient damping force against excessive tension.

[0010]

In the friction type auto tensioner according to the present invention, a movable member on an idler side is rotatably mounted on a fixed member on a fixed portion side, and the idler is moved relative to the fixed member in a direction of pressing against the belt. In a friction type auto tensioner in which a movable member is urged by a spring and a friction material is provided between a fixed member and the movable member to provide frictional resistance to rotation of the movable member by an elastic member , around a cylindrical portion of the fixed member. , the movable member having a large cylindrical portion of the inner diameter than the outer diameter is formed at one end of the cylindrical portion is rotatably supported, allowed
The spring for biasing the movable member around the cylindrical portion of the movable member is
Provided, around the cylindrical portion of the fixing member inside the cylindrical portion of the movable member, the flange member having a flange adjacent to the end face of the inner movable member of the cylindrical portion on the other hand is attached via a clutch, the movable member The elastic member for urging the flange member toward the end surface of the movable member is provided in the cylindrical portion, and the flange member is sandwiched between the elastic member and the movable member via a friction material. The rotation of the flange member in the direction of pressing against the belt is allowed, but the rotation of the flange member in the direction of separating the idler from the belt is prevented.

[0011]

On the other hand, the clutch allows the flange member to rotate in the pushing direction for pushing the idler against the belt.
When the belt is loose, the movable member rotates with the flange member relative to the fixed member, and the idler follows the looseness of the belt. At this time, the movable member and the flange member rotate with respect to the fixed member via the one-way clutch, and no relative rotation occurs at the friction material portion, so that no damping force due to friction acts. Therefore, the movable member and the idler quickly follow the slack of the belt, and the tension is maintained at a predetermined value.

On the other hand, the clutch prevents rotation of the flange member in a direction of separating the idler from the belt.
When excessive tension is applied from the belt, rotation of the flange member with respect to the fixed member is prevented by the one-way clutch, and the movable member rotates with respect to the fixed member and the flange member. Therefore, a damping force is given to the movable member by the friction material. As described above, since this damping force does not act on the movable member when the belt is loosened, the damping force can be made sufficiently large so that a large damping force acts on the movable member in case of excessive tension.

As described above, the belt quickly follows the slack of the belt and has a large damping force against excessive tension, so that the position of the idler is more stable on the pushing side where the idler is pressed against the belt than in the conventional example. The desired tension is always applied to the belt. As a result, even if the tension fluctuation is large, the belt does not become slack, and no slip noise is generated.

The periphery (outside) of the cylindrical portion of the movable member
Is provided with a spring for biasing the movable member,
A flange member, one-way clutch and a flange member are attached inside the cylinder .
Since the biasing elastic member is provided concentrically with the spring for biasing the movable member, the size of the spring increases, especially the shaft.
The increase in dimension in the direction is small. For this reason, the auto tension
The overall dimensions, especially in the axial direction, can be reduced.
Wear.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the embodiments, the left and right of the drawing are left and right.

FIG. 1 shows a first embodiment.

In FIG. 1, a perforated cylindrical fixing member (21) is attached to a bolt (2) on the left-facing surface of an engine fixing portion (20).
2) is fixed. An outward flange (21a) is integrally formed at the right end of the fixing member (21), and the remaining part is a column (21b). A flange (22b) is formed on the head (22a) of the bolt (22) so as to press against the left end surface of the cylindrical portion (21b) of the fixing member (21) and project outward from the left end.

A short columnar movable member (23) eccentric to the fixed member column portion (21b) is rotatably mounted around the left portion of the fixed member column portion (21b). Eccentric hole (24) of movable member (23)
A bush (25) is press-fitted into the housing, and a portion of the bush (25) is rotatably supported by the cylindrical portion (21b). A boss (23a) is integrally formed on the left end surface of the movable member (23), and the boss (23a)
Of the bolt (22) is close to the flange (22b) of the bolt (22). An idler (27) around a movable member (23) via a ball bearing (26)
Are rotatably mounted.

A cylindrical portion (23b) concentric with the fixed member (21) is integrally formed on the right end face of the movable member (23). The inner diameter of the cylindrical portion (23b) is larger than the outer diameters of the cylindrical portion (21b) and the flange (21a) of the fixing member (21), and the cylindrical portion (23b) has a fixed portion (2
It extends to near 0).

A torsion coil spring (28) is mounted around the movable member cylindrical portion (23b). One end (28a) of the spring (28) is attached to a pin (29) fixed to the fixed portion (20), and the other end is a spring mounting member fixed to the cylindrical portion (23b).
Installed on (30). The movable member (23) is biased by the spring (28) in a direction in which the idler (27) is pressed against a belt (not shown).

A flange member (31) is mounted via a one-way clutch (32) around the right side of the fixed member cylindrical portion (21b) inside the movable member cylindrical portion (23b). Hand clutch
(32) is a known one-roller clutch in which a plurality of rollers (32b) are arranged inside a cylindrical casing (32a), for example. The flange member (31) is formed by integrally forming an outward flange (31b) at the left end of the cylindrical portion (31a). The casing (32a) of the clutch (32) is press-fitted into the cylindrical portion (31a) of the flange member (31), and the casing (32a) and the flange member (31) are integrated with the fixed member (21). Slightly axial direction (left-right direction)
It can be moved to. The collar (31b) of the collar member (31)
A first friction material (33) in the form of a perforated disk is fixed to the right end face of the movable member (23) opposed to the first member. The cylindrical part (3
1a), a perforated disc-shaped ring member (34) is slidably fitted around the perimeter, and a perforated disc-shaped second friction material (35) is provided on the left surface of this member (34). Fixed. A retaining ring (36) is fixed to the inner periphery of the right end of the movable member cylindrical portion (23b), and a ring member (32) is provided around the flange member cylindrical portion (32a) between the retaining ring (36) and the ring member (34). A disc spring (37), which is an elastic member for urging the flange member (31) to the left through 34), is attached. The flange (3) of the flange member (31) is formed by the disc spring (37).
1b) is sandwiched between two friction members (33) and (35).

On the other hand, when the movable member (23) and the flange member (31) rotate integrally, the clutch (32) allows the rotation of the flange member (31) in the pushing direction for pressing the idler (27) against the belt. However, the flange member (31) in the direction of separating the idler (27) from the belt
Is prevented from rotating.

When the belt is loosened, the movable member (23) and the flange member (31) try to rotate in the pushing direction of pressing the idler (27) against the belt by the elastic force of the spring (28), and the flange member in this direction is rotated. Since the rotation of (31) is permitted by the one-way clutch (32), the movable member (23) rotates with the flange member (31) with respect to the fixed member (21), and the idler (27) loosens the belt. Followed and pressed against this. At this time, the movable member (23)
And the collar member (31) are connected to the fixed member (21) by one clutch (3
2), the relative rotation does not occur in the portions of the friction members (33) and (35) between the movable member (23) and the flange member (31), so that the damping force due to friction does not act. Therefore, the movable member (23)
And the idler (27) quickly follows the slack of the belt, and the tension is maintained at a predetermined value.

When excessive tension is applied from the belt, the movable member (23) and the flange member (31) try to rotate in a direction in which the idler (27) moves away from the belt against the elastic force of the spring (28). Since rotation of the collar member (31) in this direction is prevented by the one-way clutch (32), the movable member (23) rotates with respect to the fixed member (21) and the collar member (31). For this reason, the collar member (31)
The damping force is applied to the movable member (23) by the friction members (33) and (35) between them. As described above, since this damping force does not act on the movable member (23) when the belt is loosened, the damping force is made sufficiently large so that a large damping force acts on the movable member (23) in the case of excessive tension. Can be

As described above, the idler (27) is located on the pushing side where the belt comes into pressure contact with the belt because it follows the slack of the belt quickly and has a large damping force against excessive tension. It is stable and always applies the desired tension to the belt. As a result, even if the tension fluctuation is large, the belt does not become slack, and no slip noise is generated.

A flange member (31), a one-way clutch (32), a ring member (34) and a spring (37) are provided with a cylindrical portion (23b) formed at one end of a movable member (23) and a fixed member cylindrical portion. (21b) and is arranged concentrically with the spring (28) outside the cylindrical portion (23b).
Are placed, so that these increase the dimensions, especially in the axial direction.
The increase in dimension in the direction is small.

FIG. 2 shows a second embodiment.

In this case, an idler (27) is rotatably attached to the tip of a bracket (23c) formed radially outward from a part of the movable member (23) in order to increase the adjustment margin of the belt. Have been. The other parts are the same as those in the first embodiment, and corresponding parts are denoted by the same reference numerals.

FIG. 3 shows a third embodiment.

In this case, the entire flange member (31) is a flange, and no cylindrical portion is provided. The other parts are the same as those in the first embodiment, and corresponding parts are denoted by the same reference numerals.

[0031]

According to the friction type automatic tensioner of the present invention, as described above, it is possible to quickly follow the slack of the belt and to have a sufficient damping force against excessive tension. Even when the belt is large, the belt does not become slack, and the occurrence of slip noise due to the slack of the belt can be prevented. Also, if the movable member is biased
The spring that urges the collar, the collar member, the one-way clutch and the collar member
Is concentric with the outside and inside of the cylindrical part of the movable member
, So the overall dimensions, especially the axial dimensions
Can be reduced. Therefore, according to the present invention
When the auto tensioner is mounted on the car engine,
The external dimensions of the engine do not increase,
Prevents interference with other equipment in the
Can be made smaller.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a friction type auto tensioner showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a friction type auto tensioner showing a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a friction type auto tensioner showing a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a friction type auto tensioner showing a conventional example.

[Explanation of symbols]

 (20) Fixed part (21) Fixed member (21b) Cylindrical part (23) Movable member (23b) Cylindrical part (27) Idler (28) Torsion coil spring (31) Flange member (31b) Flange (32) One-way clutch ( 33) First friction material (34) Ring member (35) Second friction material (37) Disc spring (elastic member)

Claims (1)

(57) [Scope of request for utility model registration] A movable member on an idler side is rotatably mounted on a fixed member on a fixed portion side, and the movable member is biased by a spring against the fixed member in a direction in which the idler is pressed against a belt, and the movable member is movable with the fixed member. In a friction type automatic tensioner in which a friction material that gives frictional resistance to rotation of a movable member by an elastic member is provided between members, a cylindrical portion having a larger inner diameter than an outer diameter of the cylindrical portion around a cylindrical portion of the fixed member. The movable member formed at one end is rotatably supported and biases the movable member around the cylindrical portion of the movable member.
The above-mentioned spring is provided, and a flange member having a flange close to the end surface of the movable member inside the cylindrical portion is attached around the cylindrical portion of the fixed member inside the cylindrical portion of the movable member via one clutch. The elastic member for urging the flange member toward the end surface of the movable member is provided in the cylindrical portion of the movable member, and the flange member is sandwiched between the elastic member and the movable member via a friction material. However, the friction type auto tensioner is characterized in that the rotation of the flange member in the direction of pressing the idler against the belt is allowed, but the rotation of the flange member in the direction of separating the idler from the belt is prevented.