JP2981415B2 - Belt 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 improvement in a belt tensioner used for a belt driving mechanism of an automobile engine, for example.

[0002]

2. Description of the Related Art A belt tensioner is used in a transmission for transmitting a driving force to a plurality of devices with a single belt, in order to prevent the slack of the belt and to surely transmit the driving force. Such a belt tensioner is disclosed, for example, in Japanese Utility Model Laid-Open No. 5-67854.

A conventional belt tensioner (auto tensioner) as disclosed in this publication is capable of swinging a tensioner arm (swinging arm) to a tensioner cup (fixed case) fixed to a predetermined portion such as an engine block. A pulley is rotatably provided on the tensioner arm. A torsion spring is attached between the tensioner cup and the tensioner arm to bias the tensioner arm in a direction to tension the belt.

[0004] Projections are formed at predetermined intervals on the inner peripheral surface of a damping band (friction member) attached to the tensioner arm. These projections are fitted into grooves formed in the tensioner arm. This restricts the relative rotation between the damping band and the tensioner arm. A spring is provided on the inner peripheral surface of the damping band to bias the damping band toward the tensioner cup. The outer peripheral surface of the damping band is in sliding contact with the inner peripheral surface of the tensioner cup, and when the tensioner arm is rotated, a damping force (frictional force) is generated between the damping band and the tensioner cup, causing the tensioner arm to swing. Provides dynamic resistance.

[0005]

However, in the conventional belt tensioner described above, when the outer peripheral surface of the damping member on which the frictional force acts wears, the inner peripheral surface of the damping member moves radially relative to the tensioner arm. Accordingly, a gap is generated between the protrusion of the damping member and the groove of the tensioner arm. Due to this gap, noise or the like is generated when the members strike each other when the tensioner arm swings.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a belt tensioner capable of generating a damping force on a sliding surface between a tensioner cup and a damping member, the noise being suppressed even when the damping member is worn.

[0007]

Belt tensioner according to the present invention, in order to solve the problems] includes a tensioner cup, pulleys <br/> oscillating end has a lid that is attached swingably to the opening of the tensioner cup a tensioner arm mounted, one place odor sliding contact with the circumferential surface in the vicinity of the opening of the mounted tensioner cup this tensioner arm
A substantially annular damping member separated Te, Ru and a biasing means for pressing the damping member against the tensioner cup. In the present invention, such a belt tensioner is used.
, Multiple protrusions on the cover of the tensioner arm
Formed, these projections are in the axial direction of the tensioner cup
Extending from the swing center of the tensioner arm
It is provided at the eccentric position and the damping part
On the opposite side of the separated part of the material, a hole approximately the same shape as multiple protrusions
Are formed, and projections are fitted into these holes, respectively.
As a result, the damping member is
It is characterized by being attached to.

[0008]

Since the relative movement of the damping member in the circumferential direction with respect to the tensioner arm is restricted, the damping member rotates integrally with the tensioner arm when the tensioner arm swings, and a damping force is generated between the damper member and the tensioner cup. Further, even if the peripheral surface of the damping member is worn on the contact surface between the tensioner cup and the damping member, the damping member does not move relative to the tensioner arm in the radial direction. No gap is generated.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The belt tensioner of this embodiment is used, for example, in an automobile engine belt system as shown in FIG.
The belt system includes a drive pulley 1 attached to an output shaft of an engine, driven pulleys 2, 3, and 4 for an air conditioner, a power steering device, and an alternator, pulleys 5 and 6 for an idler, and a belt tensioner 10. And a single drive belt 7 is suspended between each pulley.

The belt tensioner 10 includes a fixing portion 20 fixed to the engine block, and a tensioner pulley 40 rotatably provided on the fixing portion 20 about a pivot bolt 23 serving as a swing shaft. ing. The tensioner pulley 40 is urged upward in the figure by urging means provided in the fixed portion 20, and the urging force causes the drive belt 7 to be taut. Further, when the drive belt 7 is mounted, the tensioner pulley 40 is mounted while being rotated to the position shown by the broken line in the figure.

Next, a schematic structure of the belt tensioner 10 of the embodiment will be described with reference to FIG.
The fixing portion 20 includes a mounting portion 21 having two mounting holes 21 a into which bolts (not shown) for fixing to the engine block are inserted, and a torsion spring 50.
(FIG. 3). A tensioner arm 30 is provided on the tensioner cup 22 so as to be swingable around a pivot bolt 23 which is a swing axis thereof. Tensioner pulley 40
Is rotatably provided on the tensioner arm 30 via a pulley bolt 41 which is a rotation axis parallel to the pivot bolt 23. A damping band (a damping member) 32 as a friction member is attached to the tensioner arm 30, and the outer peripheral surface of the damping band 32 is in sliding contact with the inner peripheral surface of the tensioner cup 22 from inside.

FIG. 3 is a sectional view showing the structure of the belt tensioner of this embodiment, and FIG. 4 is an exploded view showing parts of the belt tensioner.

The tensioner arm 30 has a lid portion 30b and a pulley mounting portion 30c. The lid portion 30b is swingably attached to the opening of the tensioner cup 22, and the pulley 40 is rotatably attached to the pulley attachment portion 30c. A damping band (damping member) 32 is fixed to the lid portion 30b, and the damping band 40 slides on the peripheral surface near the opening of the tensioner cup 22.

At the center of the bottom surface of the tensioner cup 22,
A bolt engaging portion 22a that stands up into the cup is formed, and a pivot bolt 23 is screwed into the bolt engaging portion 22a. A screw portion 23a is formed at the lower end of the pivot bolt 23, and a hexagonal portion 23
b is formed. By tightening the hexagonal portion 23b, the screw portion 23a is screwed into the bolt engaging portion 22a, and at a position where the lower end of the hexagonal portion 23b contacts the upper end of the bolt engaging portion 22a, the pivot bolt 23 is connected to the tensioner cup 22. Fixed to

A column 23c is provided above the hexagonal portion 23b of the pivot bolt 23, and a screw 23d is formed above the column 23c. Column part 2
3c is a hole 30 in the lid 30b of the tensioner arm 30.
h is inserted into the pivot bushing 31 fitted to the h. The movement of the pivot bushing 31 in the axial direction is regulated by a nut 24 screwed to the screw portion 23d of the pivot bolt 23, and can slide in the rotational direction with a predetermined frictional resistance. That is, the tensioner arm 30 is
It can swing about 0. In addition, pivot bushing 3
An upper O-ring and a lower O-ring may be interposed above and below 1.

The torsion spring 50 is formed by spirally winding a metal wire, and has one end 51 fixed to the bottom surface of the tensioner cup 22 and the other end 52 (FIG. 4) fixed to the tensioner arm 30. When the torsion spring 50 is appropriately twisted, the tensioner cup 22 is
The tensioner arm 30 is interposed in a compressed state between the tensioner arm 30 and the tensioner arm 30. In this state, the tensioner arm 30 is urged in a rotational direction in a direction to tension a drive belt (not shown) suspended on the tensioner pulley 40. The thickness, material, shape, and the like of the metal wire of the torsion spring 50 are appropriately selected according to the required rotation urging force.

The tensioner pulley 40 is rotatably mounted on a pulley mounting portion 30c of the tensioner arm 30 by a pulley bolt 41 via a ball bearing 42. A dust shield 43 is interposed between the head of the pulley bolt 41 and the ball bearing 42 to prevent dust from entering.

A damping band 32 as a friction member
Is attached to the tensioner arm 30. The damping band 32 is formed of an elastic member such as resin and rubber, and is made of, for example, polyacetal, a polymer material such as nylon containing molybdenum for providing self-lubricating properties, glass fiber reinforced nylon and carbon fiber reinforced plastic having excellent strength. Used.

Two circular holes 32d are formed in the inner peripheral surface of the damping band 32 so as to extend in the axial direction, and two projections projecting from the tensioner arm 30 in these circular holes 32d, ie, cylindrical pins. 30a are inserted substantially without gaps. That is, the inner diameter of the circular hole 32d is substantially the same as the outer diameter of the pin 30a, and the relative movement in the rotating direction and the radial direction of the damping band 32 with respect to the tensioner arm 30 is restricted by the pin 30a and the circular hole 32d. .

The outer peripheral surface 32a of the damping band 32 is in sliding contact with the inner peripheral surface 22b of the tensioner cup 22, and a C-shaped ring spring 33 contracts radially below the pin 30a on the inner peripheral surface of the damping band 32. Two are attached in the state where it was done. These ring springs 33 press and urge the damping band 32 toward the tensioner cup 22 with a substantially uniform and constant pressure, so that when the tensioner arm 30 swings, a damping force due to frictional force is generated in the sliding contact portion. . Ring spring 3
The biasing force by 3 is appropriately set according to the required damping force.

FIG. 5 is a side view of the tensioner arm 30, and FIG. 6 is a view when the tensioner arm 30 is viewed from the tensioner cup 22 side. The tensioner arm 30 is formed of a metal material, and has a lid 30b that rotates around a pivot axis (pivot bolt) and a pulley mounting portion 3.
0c.

An engaging portion 30d is provided on the lower surface of the lid portion 30b so as to project toward the tensioner cup 22, and the other end 52 of the torsion spring 50 (FIG. 4) is engaged with the engaging portion 30d. The cylindrical pivot bolt support portion 30e is
The pivot bolt 23 is screwed to the pivot bolt support portion 30e. Lid 3
On the side opposite to the pulley mounting portion 30c of 0b, a guide groove 30f is engraved along the outer periphery. In the lid 30b, 2
Two pins 30 a are formed, and these pins 30 a extend along the axial direction of the tensioner cup 22. A pulley bolt bearing 30 into which the pulley bolt 41 of the tensioner pulley 40 is screwed is attached to the pulley mounting portion 30c.
g is formed.

FIG. 7 is a side view of the damping band 32, and FIG. 8 is a view when the damping band 32 is viewed from the tensioner cup 22 side. Damping band 32
Has a substantially annular shape along the opening of the tensioner cup 22, and is separated at the cutting portion 32b. The cut portion 32b functions as a drain portion for absorbing the thermal deformation of the damping band 32 and for draining water that has entered the tensioner cup 22.

An insertion portion 32c is formed on the side of the damping band 32 opposite to the cutting portion 32b. Insertion part 32c
Is provided on the inner peripheral side of the damping band 32 and protrudes toward the tensioner arm 30 (upward in FIG. 7). Two circular holes 32d are formed in the insertion portion 32c, and a groove 32e for absorbing deformation of the insertion portion 32c is formed. The axis of the circular hole 32d is parallel to the pivot bolt 23, and each circular hole 32d is formed at a position that is eccentric from the pivot bolt 23 and equal in the radial direction.

A guide portion 32f and a ring receiver 32g are formed on the inner peripheral surface of the damping band 32. Guide 32
f is engaged with the guide groove 30f of the tensioner arm 30, and the ring receiver 32g is located below the ring spring 33 to prevent the ring spring 33 from shifting downward.

The belt tensioner of this embodiment is configured such that the tensioning force of the torsion spring 50
When the tensioner arm 30 is urged to rotate to tension the drive belt 7 and the tensioner arm 30 swings due to vibration of the drive belt or the like, the outer peripheral surface 32a of the damping band 32 and the inner peripheral surface 22b of the tensioner cup 22 slide. A damping force is generated at the sliding contact portion by the biasing force of the ring spring 33, thereby damping the vibration.

During use of the belt tensioner, the outer peripheral surface 32a of the damping band 32 is worn. The damping band 32 spreads outward by the action of the ring spring 33 by the amount of this wear, but the hole 32d of the damping band 32 is fitted to the pin 30a, and the gap between the damping band 32 and the tensioner arm 30 is provided. No gap occurs. Therefore, noise at the time of swinging of the tensioner arm 30 due to this gap is prevented.

The insertion portion 32c is formed on the outer peripheral surface 32 of the damping band 32 which is in sliding contact with the inner peripheral surface of the tensioner cup 22.
a, that is, at a position off the sliding contact surface. Therefore, the insertion portion 32c is not easily affected by the relative movement of the damping band 32 due to the wear of the outer peripheral surface 32a.

Further, since the plurality of pins 30a of the tensioner arm 30 are inserted into the circular holes 32d, the urging force generated by the torsion spring 50 when the tensioner arm 30 swings is distributed to the plurality of insertion points, and the damping band 32 Damage, deterioration, etc. are prevented.

[0030]

As described above, according to the present invention, in a belt tensioner for generating a damping force on a sliding contact surface between a tensioner cup and a damping member, even if the sliding contact surface of the damping member is worn, the damping member and the tensioner arm are used. No gap is generated between them, so that generation of noise can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view showing a belt system of an automobile engine.

FIG. 2 is a side view showing the appearance of the belt tensioner of the present embodiment.

FIG. 3 is a sectional view of the belt tensioner of FIG. 2;

FIG. 4 is an exploded view showing parts of the belt tensioner of FIG. 2;

FIG. 5 is a side view of the tensioner arm of FIG. 2;

FIG. 6 is a view of the tensioner arm of FIG. 2 as viewed from a tensioner cup side.

FIG. 7 is a side view of the damping band of FIG. 2;

FIG. 8 is a view of the damping band of FIG. 2 as viewed from below.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6 pulley 7 drive belt 10 belt tensioner 22 tensioner cup 22b inner peripheral surface 23 pivot bolt 30 tensioner arm 30a pin 32 damping band 32a outer peripheral surface 32d circular hole 33 ring spring 40 tensioner pulley 50 torsion spring

Claims (3)

(57) [Claims] 1. A and tensioner cup, have a lid that is attached swingably to the opening of the tensioner <br/> Kappu
One place to sliding contact with the tensioner arm pulley is attached to the oscillating end, the peripheral surface in the vicinity of the opening portion of the tensioner cup attached to the tensioner arm
And a biasing means for pressing the damping member against the tensioner cup, wherein a plurality of protrusions are formed on the lid of the tensioner arm.
These projections are in the axial direction of the tensioner cup.
Extending from the swing center of the tensioner arm.
The damping members are provided at eccentric positions, respectively, and the
Holes having substantially the same shape as the number of protrusions are formed, and the protrusions are fitted into these holes, respectively.
And the damping member is attached to the tensioner arm.
A belt tensioner characterized by being attached . 2. The shaft according to claim 2, wherein the hole is provided on the shaft of the damping member.
With respect to the sliding surface with the tensioner cup
2. The device according to claim 1, wherein
The described belt tensioner. 3. A method according to claim 1, wherein said projection is a cylindrical pin, and said hole is
Is a circular hole having substantially the same diameter as this pin.
The belt tensioner according to claim 1.