JPH0743011B2 - Auto tensioner - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt drive mechanism, which is suitable for holding an appropriate belt tension and for preventing and damping the belt tension fluctuation and resonance. It is a thing.

(Prior Art) Conventionally, an auto tensioner is used as a tension applying means in a belt transmission device in which a transmission belt is wound between a drive pulley and a driven pulley. Hydraulic tension, pneumatic pressure,
Using rubber and steel springs, resin, etc., compression, tension,
Tension is applied to the belt by means such as bending and twisting.

To give a concrete example of the means, a tensioner shaft is provided in a cylindrical case, an idler pulley is provided at the tip of this, a bearing is inserted in the inner surface, and a tension arm that also functions as a spring stopper is attached. A torsion spring is inserted in the outer circumferential surface of the tensioner shaft between the case and the tension arm. In a conventional auto tensioner, a tension arm rotates around an axis by a torsional force of a spring to apply a belt tension.

In the auto tensioner having the above structure, the idler pulley is pressed against the side surface of the belt or the like, and the tension arm oscillates in accordance with the change in the tension of the belt to give proper tension. In recent years, for the purpose of quickly converging the swing of the tension arm to reduce the load on the belt itself and the driven object, a damper having been added to the above structure has been proposed.

As a conventional damper member, a member that operates a piston or an impeller in a liquid to generate resistance is known (US Pat. No. 4,661,087).

(Problems to be Solved by the Invention) Although an autotensioner having a damper member of the related art has an advantage that the tension arm quickly stops swinging due to the resistance of the damper, it has a drawback that its outer shape is inevitably large. .

Therefore, it has been difficult to adopt the conventional auto tensioner as an auto tensioner for automobiles, etc., where the installation space of the auto tensioner is largely restricted.

Therefore, the present invention focuses on such drawbacks of the conventional auto tensioner, and an object thereof is to provide an auto tensioner having a small outer shape while having the effect of a damper.

(Means for Solving the Problems) The features of the present invention for achieving the above object are as follows.
A tension arm with an idler pulley rotatably fixed at one end is rotatably fixed to a tensioner shaft provided on a mounting member that attaches the auto tensioner to another member, and a torsion spring is installed between the mounting member or the tensioner shaft and the tension arm. In an intervening auto-tensioner, an attracting member made of a magnet or magnetic material is integrally fixed to a tension arm, made of a magnet or magnetic material, and is slidable in the circumferential direction integrally with the tensioner shaft in the axial direction. There is an autotensioner in which the pressing member fixed to the magnet is magnetically attached to the adsorption member (hereinafter, the invention of claim 1).

Another feature to achieve the same purpose based on a similar technical idea is that a tension arm having an idler pulley rotatably fixed at one end is provided on a mounting member that attaches an auto tensioner to another member. In an auto tensioner that is rotatably fixed to the tensioner shaft and has a torsion spring interposed between the mounting member or the tensioner shaft and the tension arm, the pressing member with a magnet is axially integrated with the tensioner shaft in the circumferential direction. There is an auto tensioner (invention of claim 2 below) which is slidably fixed and further has a magnet disposed between the pressing member and the mounting member or the tensioner shaft so as to face the same pole as the magnet of the pressing member.

(Operation) The auto tensioner of the present invention is installed in a state where the idler pulley is in contact with the back surface of the belt mainly on the belt loosening side of the transmission belt wound between the drive pulley and the driven pulley.

The auto tensioner of the present invention applies tension to the belt by the repulsive force of the torsion spring as in the prior art. That is, when the tension of the belt is increased, the torsion spring is wound in the direction in which it is wound and works to endure the excessive tension, and when the tension of the belt is relaxed, the torsion spring operates in the direction of unwinding and tension. The arm moves to apply tension to the belt.

Here, in the belt tensioner of claim 1, a friction member made of a magnet or a magnetic material is fixedly fixed to the tension arm, while the tensioner shaft is provided with a pressing member made of a magnet or the like so as to be movable only in the axial direction. The member and the pressing member are magnetically attached by magnetic force. Therefore, when the tension arm rotates, rubbing friction occurs between the friction member and the pressing member.

This friction acts as a resistance to prevent the autotensioner from fluttering, prevent the belt from resonating, and drive the belt while maintaining proper belt tension.

Also, when adopting the above-mentioned torsion spring with a rectangular wire cross-sectional shape, a rectangular spring with a rectangular cross-section is used under the same spring constant under the same load torque to reduce the twist angle compared to the conventional round spring. You can do it. That is, since the spring having a rectangular cross section is stronger than the round spring, it is possible to reduce the winding diameter and the number of windings under the same conditions, so that a small diameter auto tensioner can be manufactured.

According to the invention of claim 1, the pressing member is pressed against the friction member by the attraction force of the magnet as described above.
On the other hand, in the second aspect of the present invention, magnets are arranged on the back surface of the pressing member so as to face the same pole as the magnet of the pressing member, and the pressing member is brought into contact with the tension arm by the repulsive force of the magnets.

(Examples) Specific examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of an auto tensioner in a specific embodiment of the invention of claim 1. FIG. 2 is a perspective view of the pressing member.

In FIG. 1, reference numeral 1 indicates an auto tensioner. The auto tensioner 1 is composed of a fixing member 3 serving as a mounting seat for fixing to another member 2 such as an engine, a tensioner shaft 4, a tension arm 5, an idler pulley 6, a torsion coil spring 7, a friction member 8, a pressing member 9 and the like. To be done. Sequentially, the fixing member 3 has a bowl-shaped outer shape, and a side portion 18 is provided in a wall shape around the disc-shaped mounting seat portion 11. In the present embodiment, the tensioner shaft 4 is integrally provided at the center of the fixing member 3 and is tapered stepwise as the distance from the fixing seat portion 11 of the fixing member 3 increases.
The tensioner shaft 4 has a pressing member mounting portion 12 from the side closer to the fixed seat portion 10, and a rolling bearing contact portion 13 thinner than the pressing member mounting portion 12.

The pressing member mounting portion 12 is splined. The tensioner shaft 4 has a rolling bearing contact portion 13
A mounting bolt hole 14 is provided so as to penetrate from the side to the fixing member 3 side. The tension arm 5 includes a mounting portion 15 having an outer bowl shape and an arm portion 16 which are integrally coupled. Here, the mounting portion 15 further includes an outer wall portion 26 and a core portion 17. Outer wall
The outer shape of 26 is slightly larger than the side portion 18 of the fixing member 3 described above, and the inner diameter is substantially the same, and the outermost end portion is the side portion of the fixing member 3.
The inner diameter is made large so that the outermost end of 18 can be inserted. The core portion 17 is provided with a hole 20 for inserting a ball bearing.

On the other hand, the arm portion 16 of the tension arm 5 is plate-shaped,
The idler pulley 6 extends from one end of the mounting portion 15 and is attached to the tip.
Is rotatably fixed. Since the idler pulley 6 and its fixing means are not different from known ones, detailed description thereof will be omitted. Both ends of the torsion coil spring 7 are folded back so as to be engageable with the fixing member 3 and the tension arm 5 (not shown).

Moreover, the cross-sectional shape of the strand of the torsion coil spring 7 is a quadrangle, so that it is made more compact. The friction member 8 is a disk having a hole 10 in the center and made of a magnetic material such as steel or nickel, that is, a material that can be magnetized by a magnet.
The hole 10 has a diameter larger than the thickness of the pressing member mounting portion 12 of the tensioner shaft. The pressing member 9 is entirely cylindrical, and has a spline hole 31 in the center. The upper surface 32 of the pressing member 9 and the portion of the spline hole 31 are made of steel, and a cylindrical magnet 33 is inserted and fixed to the back surface of these.

The auto tensioner 1 of this embodiment is similar to the known one.
With the concave surface of the fixing member 2 and the concave surface of the tension arm 5 facing each other, the hole 20 of the mounting portion 15 of the tension arm 5 is inserted into the tensioner shaft, and the ball bearing 8 is mounted between the hole 20 and the bearing mounting portion 13. Further, a torsion coil spring 7 is mounted between the fixing member 3 and the tension arm 5 in such a state that both ends thereof are respectively locked to the fixing member 3 and the tension arm 5 and are wound and tightened with a force of several kilograms.

Although not shown, the fixed member 3 and the tension arm 5 have engaging claws that limit the rotation angle to a certain amount, and do not allow free rotation exceeding a certain rotation angle. Therefore, the tension arm 5 is constantly urged in the direction in which the torsion coil spring 7 is wound and loosened.

Further, the autotensioner of the present embodiment has a characteristic configuration in which the friction member 8 is integrally fixed to the bottom surface of the core portion 17 of the tension arm 5 with a screw (not shown),
The pressing member 9 is inserted with the spline hole 31 fitted in the spline shaft of the pressing member inserting portion 12 of the tensioner shaft 4, and the magnetic force of the magnet 33 causes the pressing member 9 and the friction member to contact each other. Tensioner shaft 4 and tension arm 5
When the core portion 17 is attached, the bottom surface 33 of the pressing member 9 is set so as not to contact the inner bottom portion of the fixing member 3 and to have a slight gap. The present auto tensioner is used by pressing the idler pulley 6 against the belt in a state where the tension arm 5 is manually moved to provide an operating margin of the tension arm 5. At this time, since the tension arm 5 is biased by the torsion coil spring 7 with a constant force, a constant tension is applied to the belt.
When the belt vibrates due to load fluctuations and engine speed fluctuations, the pressing member 9 is magnetically attached to the friction member 8 by magnetic force, and the pressing member 9 is movable by splines in the axial direction of the tensioner shaft. Further, since it is fixedly fixed in the rotation direction, friction is generated between the friction member 8 and the pressing member 9. This friction acts as a resistance to damp the vibration of the belt. When the engine or the automobile itself vibrates significantly, the pressing member 9 may be separated from the friction member 8. However, since the gap between the pressing member 9 and the fixed member 3 is small, the pressing member 9 is affected by the magnetic force. It recovers by suction by itself.

In the above configuration, the friction member is made of a magnetic material such as steel, is manufactured separately from the tension arm, and is attached to the tension arm.

However, the friction member can also function as a part of the tension arm if the tension arm itself is made of a magnetic material.

It is also possible to manufacture the friction member itself with a magnetic material or to dispose a material having a high friction coefficient on the surface thereof to promote the generation of frictional force.

Next, an embodiment of the invention of claim 2 will be described. FIG. 3 is a sectional view of an auto tensioner in a concrete embodiment of the invention of claim 2. The autotensioner according to claim 1 described above generates a frictional force by pressing the pressing member against the friction plate by using the attraction force of the magnet, but the autotensioner described below uses the repulsive force of the magnet. The friction plate is pressed to generate a predetermined friction resistance.

The autotensioner of the second embodiment is the same as the above-mentioned autotensioner except that the magnet 40 is provided and the friction member 8 is not provided. Therefore, the same numbers are assigned to the respective members, and detailed description thereof is omitted.

In this embodiment, the pressing member 9 does not use a friction member,
It is in direct contact with the bottom surface of the tension arm 5. The magnet 40 is fixed to the inner surface of the mounting member 2 with the same pole as the inner surface of the pressing member 9 facing.

Therefore, the pressing member 9 repels the magnet 40, and the upper surface of the pressing member 9 is pressed by the tension arm 5 with a predetermined force. Therefore, similar to the previous embodiment, when the tension arm rotates, frictional resistance is generated between the pressing member and the tension arm, and the vibration of the belt is converged.

Also in this embodiment, the pressing member may not be directly in contact with the tension arm, but a friction material such as rubber, asbestos, nylon or copper may be interposed.

Although the pressing member is arranged between the tension arm and the fixing member in the embodiments of claims 1 and 2 above, it may be arranged outside the tension arm.

In this case, in the invention of claim 2, the magnet is fixed to the arm portion 16 of the tension arm.

(Effect) In the auto tensioner of the present invention, the pressing member is arranged on the mounting member or the tensioner shaft so as to be slidable in the axial direction but not allowed to rotate, and the pressing member is attracted or repelled by the magnet. It presses the tension arm at a predetermined position.

Therefore, when the tension arm rotates, a frictional force is generated, which has the effect of preventing the resonance of the belt.

[Brief description of drawings]

FIG. 1 is a sectional view of an auto tensioner in a specific embodiment of the invention of claim 1. FIG. 2 is a perspective view of the pressing member. FIG. 3 is a sectional view of an auto tensioner in a specific embodiment of the invention of claim 2. 1 …… Auto tensioner 3 …… Fixing member 4 …… Tensioner shaft 5 …… Tension arm 6 …… Idler pulley 7 …… Torsion coil spring 8 …… Friction member 10 …… Friction plate 33 …… Magnet 40 …… Magnet

Claims (2)

[Claims] 1. A tension arm having an idler pulley rotatably fixed at one end is rotatably fixed to a tensioner shaft provided on a mounting member for mounting an autotensioner to another member, and the tension arm is provided between the mounting member or the tensioner shaft and the tension arm. In an automatic tensioner with a torsion spring interposed, a friction member made of a magnet or a magnetic material is integrally fixed to a tension arm and made of a magnet or a magnetic material. The automatic tensioner is characterized in that a pressing member slidably fixed to the is magnetically attached to the friction member. 2. A tension arm having an idler pulley rotatably fixed to one end thereof is rotatably fixed to a tensioner shaft provided on a mounting member for mounting an auto tensioner to another member, and the mounting member or the tensioner shaft and the tension arm. In an auto-tensioner having a torsion spring interposed therebetween, a pressing member having a magnet is integrally fixed to a tensioner shaft in the circumferential direction so as to be slidable in the axial direction. An auto tensioner in which a magnet is arranged between the magnets of the pressing member so as to face the same pole.