JPH0596595U - Friction type automatic tensioner - Google Patents

Abstract

(57) [Abstract] [Purpose] The movement of the friction material is smooth, and the friction material does not fall or hit. [Structure] The movable member 5 on the idler 6 side is rotatably attached to the fixed member 2 on the fixed portion 1 side, and the movable member 5 is spring 13 with respect to the fixed member 1 in the direction in which the idler 6 presses against the belt.
A columnar friction material 20 for applying a frictional resistance to the rotation of the movable member 5 is movably fitted into a circular guide hole 10 formed in the movable member 5 and pressed against the fixed member 2 by a spring 12. The outer diameter of the friction material (20) is made slightly smaller than the inner diameter of the guide hole (10), and a protrusion portion (21) contacting the inner peripheral surface of the guide hole (10) is formed on the outer peripheral surface of the friction material (20).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an auto tensioner that applies a predetermined tension to a V-belt used to drive an auxiliary machine of an automobile.

[0002]

[Prior Art]

 As this type of auto tensioner, those shown in FIGS. 6 and 7 are known. In the description of these drawings, the left and right of FIG. 6 are referred to as the left and right.

In FIGS. 6 and 7, a fixing member (2) is fixed to the leftward surface of a fixed portion (eg, engine block) (1) of the engine. The fixing member (2) is composed of a base plate portion (2a), an inner cylindrical portion (2b) and an outer cylindrical portion (2c) integrally concentrically formed on the left side surface of the substrate portion (2a), A portion of the substrate portion (2a) outside the cylindrical portion (2b) is fixed to the fixing portion (1) by a plurality of bolts (3). The cylindrical part (2b) projects slightly to the left of the cylindrical part (2c).

A movable member (5) is rotatably attached around the cylindrical portion (2b) of the fixed member. The movable member (5) consists of a thick-walled cylindrical portion (5a), an outward facing flange portion (5b) formed at its left end, and a short cylindrical portion formed rightward from the outer peripheral portion of this flange portion (5b). (5c) and a bracket part (5d) that is formed radially outward from a part of this short cylindrical part (5c) .The idler (tension pulley) (6d) is attached to the end of the bracket part (5d). ) Is rotatably attached. The movable member thick-walled cylindrical portion (5a) is rotationally fitted around the fixed member cylindrical portion (2b). The stopper (7) is fixed to the left end surface of the fixed member columnar part (2b) with a bolt (8), and the washer (9) fitted to the left end surface of the movable member (5) is connected to the stopper (7). Sandwiched between. A plurality of circular guide holes (10) are formed on the right end surface of the thick walled cylindrical part (5a) of the movable member, and the cylindrical friction material (11) slides on the right opening end of these holes (10). A compression coil spring (12) is fitted between the bottom of the hole (10) and the friction material (11). Then, the block-shaped friction material (11) is pressed against the fixed member substrate portion (2a) by the spring (12), and the left end surface of the movable member thick-walled cylindrical portion (5a) is stopped via the washer (9). Pressed against (7).

The right end side of the movable member thick-walled cylindrical portion (5a) fits inside the fixed member cylindrical portion (2c) with a gap, and the left end of the fixed member cylindrical portion (2c) and the movable member short cylindrical portion (5c). The right edge of is close. Inside the cylindrical portions (2c) and (5c), a torsion coil spring (13) is fitted in an annular space surrounding the movable member thick-walled cylindrical portion (5a). One end of this spring (13) is attached to the fixed member (2) and the other end is attached to the movable member (5), which allows the idler (6) to move in the direction of pressure contact with the belt (14). Member (5) is energized.

A rotation restricting groove (15) is formed on the left end surface of the fixed member cylindrical portion (2c) over a predetermined range in the circumferential direction. A rotation regulating pin (16) protruding rightward is fixed to the movable member short cylindrical portion (5c), and the right end portion of the pin (16) is fitted in the rotation regulating groove (15). The groove (15) and the pin (16) regulate the rotation range of the movable member (5).

When excessive tension is applied from the belt (14), the movable member (5) rotates in the direction in which the idler (6) moves away from the belt (14), and when the belt loosens, the spring (13) causes The movable member (5) rotates in the pushing direction in which the idler (6) presses against the belt. In either case, the friction material (11) imparts a damping force to the rotation of the movable member (5), thereby exerting a damper effect.

[0008]

[Problems to be solved by the device]

 In the friction type automatic tensioner as described above, the columnar friction material (11) moves in the guide hole (10) in the left-right direction and is always in pressure contact with the fixing member substrate portion (2a). If the clearance between the friction material (11) and the guide hole (10) is made too small, the movement of the friction material (11) will be impaired and sufficient friction resistance will not be obtained. The outside diameter of (11) is made a little smaller than the outside diameter of the guide hole (10), and the clearance between them is increased to some extent.

However, if the clearance is increased in this way, the friction material (11) may fall, or the friction material (11) may collide with the inner peripheral surface of the guide hole (10) and generate a tapping sound. There is such a problem.

An object of the present invention is to solve all of the problems described above, and to provide a friction type automatic tensioner in which the movement of the friction material is smooth and in which the friction material does not fall or hit.

[0011]

[Means for Solving the Problems]

 In the friction type auto tensioner according to the present invention, the movable member on the idler side is rotatably attached to the fixed member on the fixed portion side, and the movable member is biased by the spring against the fixed member in the direction in which the idler presses against the belt. A cylindrical friction material for giving frictional resistance to the rotation of the movable member is movably fitted in a circular guide hole formed in one of the fixed member and the movable member and pressed against the other member by a spring. In the friction type auto tensioner used, the outer diameter of the friction material is slightly smaller than the inner diameter of the guide hole, and the outer peripheral surface of the friction material is formed with a protrusion that contacts the inner peripheral surface of the guide hole. It is what

[0012]

[Action]

 The outer diameter of the friction material is slightly smaller than the inner diameter of the guide hole, and the protrusion formed on the outer peripheral surface of the friction material is only in contact with the inner peripheral surface of the guide hole, so that the friction material moves smoothly. Further, since the protrusion is in contact with the inner peripheral surface of the guide hole, it is possible to prevent the friction material from collapsing or hitting sound.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. In the description of the practical example, the left and right in FIG.

FIG. 1 shows the entire structure of the automatic tensioner in the same manner as in FIG.

The autotensioner of this embodiment is the same as the conventional autotensioner of FIGS. 6 and 7, except that the columnar friction material (20) is different. In FIG. 1, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

Details of the cylindrical friction material (20) are shown in FIGS. 2 and 3.

The friction material (20) is composed of a large diameter cylindrical part (20a) on the right side and a small diameter cylindrical part (20b) on the left side, and the right end of the spring (12) is fitted to the outside of the cylindrical part (20b). Are pressed against the annular surface at the left end of the cylindrical part (20a). The outer diameter of the cylindrical portion (20a) is slightly smaller than the inner diameter of the guide hole (10) so that it can smoothly move left and right in the guide hole (10). Protrusions (projections) (21) extending in the axial direction of the columnar part (20a) are integrally formed at a plurality of locations that equally divide the outer peripheral surface of the columnar part (20a) in the circumferential direction. Both the width in the circumferential direction and the height in the radial direction of these ridges (21) are small. Also, the diameter of the circle passing through the radially outer edge of these ridges (21) is slightly smaller than the inner diameter of the guide hole (10), and when the columnar part (20a) is fitted into the guide hole (10). The ridges (21) are elastically deformed so that they are pressed against the inner peripheral surface of the guide hole (10) with a slight force.

In the above auto tensioner, the outer diameter of the cylindrical portion (20a) of the friction material (20) is slightly smaller than the inner diameter of the guide hole (10), and the width formed on the outer peripheral surface of the cylindrical portion (20a) is small. Since the ridge (21) is only in contact with the inner peripheral surface of the guide hole (10), the movement of the friction material (20) is smooth, and the friction material (20) is always fixed to the base member (2a). It can be pressed against to provide a proper friction resistance. If the ridge (21) is made to have an appropriate length, the ridge (21) is in contact with the inner peripheral surface of the guide hole (10) to prevent the friction material (20) from collapsing, resulting in friction. The material (20) does not collide with the inner peripheral surface of the guide hole (10) and a tapping sound is not generated.

4 and 5 each show a modification of the cylindrical friction material (20).

In the case of FIG. 4, a plurality of spiral protrusions (protrusions) (22) are integrally formed on the outer peripheral surface of the cylindrical portion (20a).

In the case of FIG. 5, a plurality of annular projections (projections) (23) are integrally formed on the outer peripheral surface of the columnar part (20a).

[0022]

[Effect of the device]

 According to the auto tensioner of the present invention, as described above, it is possible to smooth the movement of the friction material and prevent the friction material from collapsing or hitting.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a friction type automatic tensioner showing an embodiment of the present invention.

FIG. 2 is an enlarged side view showing the cylindrical friction material of FIG.

FIG. 3 is a front view of the friction material of FIG.

FIG. 4 is a side view showing a modified example of a cylindrical friction material.

FIG. 5 is a side view showing another modified example of the cylindrical friction material.

FIG. 6 is a vertical sectional view of an automatic tensioner showing a conventional example.

7 is a front view of the auto tensioner of FIG.

[Explanation of symbols]

 (1) Fixed part (2) Fixed member (5) Movable member (6) Idler (10) Circular guide hole (12) Compression coil spring (13) Torsion coil spring (14) Belt (20) Cylindrical friction material (21 ) Protrusions (protrusions) (22) Protrusions (protrusions) (23) Protrusions (protrusions)

Claims (1)

[Scope of utility model registration request] 1. A movable member on the idler side is rotatably attached to a fixed member on the fixed portion side, and the movable member is urged by a spring against the fixed member in a direction in which the idler is pressed against the belt to rotate the movable member. A cylindrical friction material for giving frictional resistance to a movable member is movably fitted in a circular guide hole formed in one member of a fixed member and a movable member and is pressed against the other member by a spring. In the tensioner, an outer diameter of the friction material is slightly smaller than an inner diameter of the guide hole, and a protrusion portion that is in contact with an inner peripheral surface of the guide hole is formed on an outer peripheral surface of the friction material.