JPH11141629A - Auto tensioner - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the size of an auto tensioner. An arm is attached to a base.
The shaft 34 of the arm 30 is connected to the base 2 via bearings 25 and 35.
0 in the bearing portion 24. Pulley 60 on arm 30
Attach. A torsion coil spring 50 is wound between the arm 30 and the base 20. The torsion coil spring 50 urges the arm 30 in the direction in which the belt tensions. The cup 80 is attached to the shaft lower surface 34b. Base 2
The zero pin 28 is inserted into the engagement hole 72 of the damping band 70, and the damping band 70 is attached to the base 20. When the arm 30 swings due to the vibration of the belt suspended on the pulley 60, the damping band 70
It slides within 0 and dampens the swing of the arm 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto tensioner used for driving a belt accessory of an automobile engine, for example.

[0002]

2. Description of the Related Art An automatic tensioner is used for a transmission device that transmits driving force to a plurality of devices with a single belt, and prevents the belt from being loosened so that the driving force is transmitted to each device reliably. Such an auto-tensioner includes, for example, a cup fixed to a predetermined portion such as an engine block, an arm swingably supported by the cup, and a pulley rotatably attached to the arm. I have. The belt is suspended on the side surface of the pulley, and is urged in a tensioning direction. The biasing force for tensioning the belt is generated by a repulsive force of a torsion coil spring wound around a predetermined torsion force and disposed in the cup.

[0003] A torsion coil spring and a damping mechanism are provided in the cup. The damping mechanism is provided to attenuate the swing of the arm due to the vibration of the belt or the like. A ring spring.
The cup diameter is set to be larger by a predetermined length than the diameter of the torsion coil spring so that the damping mechanism does not interfere with the torsion coil spring.

[0004]

However, in order to obtain a desired biasing force, a predetermined length of the torsion coil spring is required. In a configuration in which the torsion coil spring and the damping band are provided in the cup, the size of the cup is reduced. Conversion was limited.

It is an object of the present invention to reduce the size of an auto tensioner without reducing a constant belt urging force.

[0006]

According to the present invention, there is provided an auto tensioner in which a base having a mounting plate and a bearing protruding from one surface of the mounting plate is integrally formed with a rotating shaft passing through the bearing. And an arm rotatable around the rotation axis with respect to the base, one end is attached to one surface of the mounting plate portion, and the other end is attached to the arm, and the arm is wound around the rotation axis. It is characterized by comprising a torsion coil spring for urging in a predetermined rotation direction, and a damping mechanism provided on the other surface of the mounting plate portion to impart resistance to the rotational movement of the arm.

[0007] In the auto tensioner, the damping mechanism may be integrally attached to the rotating shaft.

In the automatic tensioner, a damping mechanism includes a cup fixed to a rotating shaft, a damping band attached to a pin protruding from the other surface of the mounting plate, and slidingly in contact with an opening surface of the cup. A ring spring biasing the cup from the peripheral surface side may be provided.

In the automatic tensioner, the damping mechanism includes a friction member, a plurality of compression coil springs for urging the friction member against the base, and a casing for accommodating the compression coil spring and attached to a rotating shaft of the arm. Is also good.

In the automatic tensioner, the damping mechanism may include a friction member and a disc spring for urging the friction member against the base.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an auto tensioner according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a diagram showing a belt system of an automobile engine using an auto-tensioner according to this embodiment. The belt system includes a driving pulley 11 attached to an output shaft of an engine, and driven pulleys 1 for an air conditioner, a power steering device, and an alternator.
2, 13, 14, idler pulleys 15, 16, and an auto-tensioner (hereinafter referred to as a tensioner) 10. A single drive belt 17 is suspended between each pulley, and the drive belt 17 is driven clockwise.

The tensioner 10 has a base 20, which is fixed to the engine block 18. The tensioner 10 has an arm 30. The arm 30 is rotatable around an axis (not shown) with respect to the base 20. A pulley 60 is attached to the arm 30, and the pulley 60 is rotatable with respect to the arm 30. The drive belt 17 is suspended around the outer peripheral surface of the pulley 60. The pulley 60 is urged counterclockwise from a position indicated by a solid line by a torsion coil spring (not shown) to a position indicated by a broken line, and tensions the drive belt 17.

FIGS. 2 to 5 show an auto-tensioner according to a first embodiment. 2 is a sectional view of the tensioner 10, FIG. 3 is an exploded perspective view showing a structure other than the pulley 60, FIG. 4 is a top view of the base 20, and FIG.

The base 20 has a disk-shaped mounting plate 21 and 2
The two mounting portions 22 and the cylindrical bearing portion 24 are integrally formed. The mounting portion 22 is fixed to the engine block by bolts (not shown). Upper surface 2 of mounting plate 21
1a, a bearing portion 24 extends in a direction perpendicular to the mounting plate portion 21, and the bearing portion 24 has two bearings 25, 35.
, The shaft 34 of the arm 30 is inserted.

The arm 30 is a metal member and has an eccentric 2
The rotating plate 32 and the pulley mounting plate 42 are integrally formed. A cylindrical shaft 34 extends downward from the lower surface 32b of the rotating plate 32. The shaft 34 is rotatable within the bearings 25 and 35 with a predetermined frictional resistance, that is, the arm 30 is rotatable around the shaft 34 with respect to the base 20.

A pulley shaft 44 is formed in the center of the pulley mounting plate 42 in a direction parallel to the shaft 34 and extends in the opposite direction. The pulley 60 is mounted on the pulley shaft 44 by pulley bolts 68. Pulley 60 and pulley shaft 44
A ball bearing 62 is interposed therebetween, so that the pulley 60 is rotatable with respect to the pulley shaft 44.
Between the head of the pulley bolt 68 and the ball bearing 62, a dust shield 64 for preventing intrusion of dust is interposed.

The torsion coil spring 50 is formed, for example, by spirally winding a metal wire having a circular cross section.
The thickness, material, and shape of the metal wire or the number of turns of the torsion coil spring are appropriately selected according to the required belt tension. The torsion coil spring 50 is interposed in a compressed state between the base 20 and the arm 30 in an appropriately twisted state, and in this state, tensions the drive belt 17 (FIG. 1) suspended on the pulley 60. The arm 30 is energized. One end (hereinafter, referred to as a base side end) 52 of the torsion coil spring 50 is attached to the mounting plate 21 of the base 20.
The other end (hereinafter, referred to as an arm side end) 56 is attached to the rotating plate 32 of the arm 30 and wound around the axis 34.

The base end 52 is formed in a straight line.
As shown in FIG. 4, the base side end 52 is
Is engaged with the spring receiving portions 26, 27, 29 formed on the upper surface 21a of the mounting plate portion 21. Thus, the torsion coil spring 50 is fixed in the radial direction and the circumferential direction.
The arm side end 56 is formed by bending outward from the spiral portion 54 in the radial direction. As shown in FIG.
Engages with spring receiving portions 36 and 37 formed on the lower surface 32 b of the rotating plate of the arm 30, whereby the circumferential and radial positions of the torsion coil spring 50 are regulated. Further, the torsion coil spring 50 is
The position in the direction of the helical axis, that is, in the direction of the axis 34, is regulated by the upper surface 21a of the disk portion and the lower surface 32b of the rotating plate of the arm 30.

The damping mechanism is provided to prevent the arm 30 from swinging excessively. For example, a friction member (hereinafter, referred to as a damping band) which comes into contact with the base 20 and moves integrally with the arm 30 is provided. Accordingly, the swing of the arm 30 is attenuated by the damping force generated at the time of friction. In the present embodiment, a damping band 70 is attached to the base 20, and a cup 80 integrally fixed to the shaft 34 of the arm 30 slides on the damping band 70 to generate a damping force.

The damping band 70 is a substantially annular member formed of an elastic member such as a nylon resin. FIG.
As shown in FIG. 5, fitting holes 72 for fitting with two pins 28 (only one is shown in FIG. 3) of the base 20 are formed at the end fixed to the base 20. Mating hole 7
An opening 74 extending in the axial direction is formed on the side surface opposite to the side 2. The opening 74 absorbs the thermal deformation of the damping band 70 and gradually expands when the damping band 70 is worn, so that the elastic deformation of the damping band 70 is possible so that the urging force of the ring spring 75 can be sufficiently transmitted. Become. Flange 7 at base end
6 are formed to prevent intrusion of dust on the contact surface with the cup 80.

The ring spring 75 is made of a metal wire C
It is a shaped spring and attached to the inner peripheral surface of the damping band 70 in a state of being contracted in the radial direction. When mounted on the damping band 70, the axial position of the ring spring 75 is regulated by two spring receivers 77 and 78 formed on the inner peripheral surface of the damping band 70. The ring spring 75 has a square cross section, and the plate width (radial dimension) gradually increases from the opening. Two ring springs 75 are stacked in the axial direction. The ring spring 75 moves the damping band 70 substantially uniformly in the circumferential direction from the inner side of the cup inner peripheral surface 80a.
Energize toward.

The cup 80 has a raised portion 82 which rises from the center of the bottom surface toward the opening side. The raised portion 82 is attached to the bottom surface 34b of the shaft 34 from the bottom surface side by bolts 85. When the cup 80 is attached to the shaft 34, the raised portion upper surface 82a and the shaft bottom surface 34b are in close contact with each other,
The cup inner peripheral surface 80a and the damping band outer peripheral surface 70a are in close contact with each other. The inside of the cup 80 is substantially sealed by the close contact surface.

The vibration from the drive belt 17 (FIG. 1) is transmitted to the arm 30 via the pulley 60. The arm 30 swings around the axis 34 to absorb the vibration of the pulley 60. When the arm 30 swings, the cup 80 rotates with the rotation of the shaft 34, and the damping band 70
The sliding contact between the arm 30 and the cup 80 generates a damping force, thereby damping the swing of the arm 30. This damping force is constant regardless of the torsional force of the torsion coil spring 50.

As described above, in the auto tensioner 10 of the first embodiment, the torsion coil spring 50 is provided above the base 20, and the damping mechanism is provided below the base 20. Conventionally, a torsion coil spring is housed in a tensioner cup corresponding to the base 20, and a damping member is provided between the tensioner cup and the torsion coil spring. However, the first embodiment does not house the torsion coil spring 50 in the cup 80. Therefore, it is not necessary to set the diameter of the cup 80 larger than the diameter of the torsion coil spring 50 as compared with the conventional configuration, and the cup volume can be reduced. That is, the entire auto tensioner can be reduced in size without being restricted by the design of the torsion coil spring 50.

FIGS. 6 and 7 show an auto-tensioner according to a second embodiment. FIG. 7 is an exploded perspective view showing the configuration of the damping mechanism. The auto tensioner of the second embodiment is the same as the first embodiment except that the damping mechanism is different. The same components have the same reference characters allotted, and description thereof will not be repeated.

The lower surface 21b of the rotating plate of the base 20 is formed flat. The friction member 170 is a ring-shaped plate member, and three cylindrical projections 172 are formed on the lower surface 170b. The cylindrical projections 172 are provided at equal intervals in the circumferential direction. The friction member 170 is a compression spring case 180
Is attached to the shaft 34 of the arm 30 by a bolt 185. The compression spring case 180 includes three holes 182 that engage with the cylindrical projections 172, and three spring holes 184 for receiving the compression springs 174. The compression spring 174 is a coil spring, and is stored in the spring hole 184 in a compressed state.

When the compression spring case 180 is mounted, the compression spring 174
70 is pressed against the rotating plate lower surface 21b of the base 20, whereby the upper surface 170a of the friction member 170 and the rotating plate lower surface 21b of the base 20 come into close contact with each other. When the shaft 34 is rotated by the swing of the arm 30, the upper surface 170a of the friction member 170 is rotated.
Slides on the rotating plate lower surface 21b of the base 20, thereby generating a damping force.

In the second embodiment, as in the first embodiment, a damping mechanism is provided at a position opposite to the torsion coil spring 50 with respect to the base 20, so that the tensioner 1 can be used regardless of the design of the torsion coil spring 50.
0 is achieved.

FIG. 8 shows an auto-tensioner according to a third embodiment. The auto-tensioner of the third embodiment is the same as the first embodiment except that the damping mechanism is different. The same components have the same reference characters allotted, and description thereof will not be repeated.

The rotating plate lower surface 21b of the base 20 is formed flat. A fixing member 280 having a flange 282 is screwed and fixed to the swing shaft 34 with a bolt 285.
A friction member 270 and two disc springs 260 and 265 are interposed between the lower surface 21b of the rotating plate of the base 20 and the upper surface 282a of the flange of the fixing member 280. Friction member 27
Numeral 0 is a plate material formed in a ring shape, and its upper surface 270
a is in close contact with the rotating plate lower surface 21b. Disc spring 260,
265 is provided with a hole in the center for penetrating the fixing portion, and the dish bottoms are provided in close contact with each other. Disc Springs 260, 265
Are formed with flat outer edges, the outer edge 262 of the disc spring 260 on the base 20 side is in close contact with the friction member 270, and the outer edge 267 of the opposite disc spring 265 is fixed on the fixing member 2
It is in close contact with the flange 282 of 80.

In the state shown in FIG.
265 is interposed in a state of being compressed in the axial direction, whereby the friction member 270 is pressed and urged toward the base lower surface 21b. When the shaft 34 is rotated by the swing of the arm 30,
The friction member upper surface 270a slides with respect to the rotating plate lower surface 21b, thereby generating a damping force.

In the third embodiment, as in the first embodiment, a damping mechanism is provided at a position opposite to the torsion coil spring 50 with respect to the base 20, so that the tensioner 1 can be used regardless of the design of the torsion coil spring 50.
0 can be reduced in size.

FIG. 9 shows an auto-tensioner according to a fourth embodiment. The auto tensioner of the fourth embodiment is the same as the first embodiment except that the configuration of the shaft is different.
The same components have the same reference characters allotted, and description thereof will not be repeated.

The shaft 334 has a screw portion 334a at the upper end. The screw portion 334a is screwed with the rotating plate 32 of the arm 30, so that the arm 30 and the shaft 334 can rotate integrally. Although not shown, a screw portion is also provided at the lower end of the shaft 334, and the nut 38 is connected via a cup 80.
5 tightened. This allows the cup 80 to be
34.

In the fourth embodiment, as in the first to third embodiments, a damping mechanism is provided at a position on the opposite side of the torsion coil spring 50 with respect to the base 20, regardless of the design of the torsion coil spring 50. Thus, the size of the tensioner 10 can be reduced.

As described above, in the auto tensioners shown in the first to fourth embodiments, the torsion coil spring is not provided in the cup, and the damping mechanism is provided at a position facing the torsion coil spring with respect to the base. ing. Therefore, it is not necessary to set the size of the cup larger than the diameter of the torsion coil spring, and the size of the auto tensioner can be reduced.

[0038]

According to the present invention, the size of the auto-tensioner can be reduced without reducing the constant belt urging force.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a belt system using an embodiment of an auto tensioner according to the present invention.

FIG. 2 is a cross-sectional view showing a first embodiment of the auto tensioner according to the present invention.

FIG. 3 is an exploded perspective view showing a configuration in which an arm and a damping mechanism of the auto tensioner shown in FIG. 2 are mounted on a base.

FIG. 4 is a top view of the base shown in FIG. 2;

FIG. 5 is a bottom view of the arm shown in FIG. 2;

FIG. 6 is a sectional view showing a second embodiment of the auto tensioner according to the present invention.

FIG. 7 is an exploded perspective view showing a damping mechanism of the auto tensioner shown in FIG.

FIG. 8 is a sectional view showing a third embodiment of the auto tensioner according to the present invention.

FIG. 9 is a sectional view showing a fourth embodiment of the auto tensioner according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Auto tensioner 20 Base 25, 35 Bearing 30 Arm 50 Torsion coil spring 60 Pulley 70 Damping band 75 Ring spring 80 Cup

Claims (5)

[Claims] A base provided with a mounting plate and a bearing protruding from one surface of the mounting plate; and a rotating shaft penetrating the bearing. An arm rotatable around a rotation axis, one end of which is attached to one surface of the mounting plate, and the other end of which is attached to the arm, and which is wound around the rotation axis, thereby rotating the arm in a predetermined rotation direction. An auto-tensioner, comprising: a torsion coil spring biasing the arm; and a damping mechanism provided on the other surface of the mounting plate portion to impart resistance to the rotational movement of the arm. 2. The auto-tensioner according to claim 1, wherein the damping mechanism is integrally attached to the rotating shaft. 3. A damping mechanism in which the damping mechanism is fixed to the rotating shaft, a damping band attached to a pin protruding from the other surface of the mounting plate, and slidably in contact with an opening surface of the cup. And a ring spring for urging the cup from the inner peripheral surface side to the cup. 4. The damping mechanism includes a friction member, a plurality of compression coil springs for urging the friction member against the base, and a casing that houses the compression coil spring and is attached to a rotation shaft of the arm. The auto-tensioner according to claim 2, wherein: 5. The auto-tensioner according to claim 2, wherein the damping mechanism includes a friction member and a disc spring for urging the friction member against the base.