JPH11201247A - Auto-tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attach a means to control an oscillation range of an arm easily with low manufacturing cost in an auto-tensioner. SOLUTION: An auto-tensioner A is provided with an arm 2 of which one end is rotatively supported on a fixed support shaft 1 and a tension pulley is rotatively supported on the other end. A stopper pin 26 for controlling an oscillation range of the arm 2 and range controlling parts 15 and 16 are provided separately in the support shaft 1 and the arm 2, and the stopper pin 26 is press fitted in and attached to a hole 25 to be provided either on the support shaft 1 or the arm 2. By adopting this structure, the complicated attachment work of screw type for example can be avoided and the machining such as polishing of outer surface of the stopper pin 26 and inner surface of the hole 25 can be omitted by making a part of a circumference of the stopper pin 26 to be a separate split pin.

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 automatically maintaining a proper belt tension of a belt drive mechanism provided in an automobile engine or the like.

[0002]

2. Description of the Related Art In this type of auto tensioner, usually,
As shown in the microfilm of Japanese Utility Model Laid-Open No. 5-52413, in order to regulate the swing range of the pulley arm, a stopper pin and a regulating groove are separately provided on the pulley arm and a fixing member supporting the pulley arm.

[0003] As the above-mentioned stopper pin, for example, a single-diameter press-fit pin, screw, or a cylindrical member having a circumferential surface almost half of the longitudinal direction having a small diameter is considered.

That is, these stopper pins are mounted in cylindrical holes, screw holes, and the like provided in the pulley arm.

[0005]

By the way, in the above-mentioned conventional auto-tensioner, whether the inner peripheral surface of the hole provided in the pulley arm is formed into a cylindrical shape, a thread groove, or another processing after forming the hole. It is pointed out that the manufacturing cost is high.

Also, in the case of the press-fit type, the stopper pin also requires another processing after formation such as polishing of the peripheral surface, and the manufacturing cost is high. On the other hand, in the case of the screw type, a commercially available product can be diverted, but it is pointed out that the assembling efficiency is poor, for example, the work at the time of mounting is troublesome and time-consuming.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a means for restricting the swing range of an arm in an auto tensioner so that it can be easily mounted with a low manufacturing cost.

[0008]

According to a first aspect of the present invention, there is provided an auto tensioner having one end rotatably supported by a fixed support shaft and the other end rotatably supported by a tension pulley. An arm is provided, and a stopper pin for regulating the swing range of the arm and a range regulating portion are provided separately for the support shaft and the arm, and the stopper pin is a split pin which is a part of the circumference separated. Is mounted by press-fitting into a hole provided in the member to be mounted.

[0009] The auto tensioner according to claim 2 of the present invention comprises:
In the above-mentioned claim 1, the stopper pin is provided on the outer periphery of the rotation support portion with respect to the support shaft of the arm, and the range restricting portion is provided on the outer periphery of the support shaft, respectively. A tongue piece protruding radially outward is provided, and a hole penetrating in the axial direction is provided in this tongue piece,
The stopper pin is attached to this hole by press-fitting, and at two locations circumferentially separated on the outer periphery of the support shaft, convex wall portions projecting outward in the radial direction are provided as range control portions. A stopper pin is arranged in an inner space sandwiched between the two convex wall portions.

As described above, in the present invention, the structure in which the stopper pin is mounted by press-fitting into the hole provided in either the support shaft or the arm is employed, thereby avoiding the complicated mounting work such as the screw type. doing. Then, by making the stopper pin a split pin that is partially separated on the circumference, processing such as polishing on the outer peripheral surface of the stopper pin and the inner peripheral surface of the hole for mounting the stopper pin can be omitted. I have.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS.

1 to 5 relate to an embodiment of the present invention. FIG. 1 is a front view of an auto-tensioner, FIG. 2 is a sectional view taken along line (2)-(2) of FIG. 1, and FIG. FIG. 4 is a perspective view of a part of the auto tensioner, FIG. 4 is a view showing a state in which a boss portion of an arm and a stopper pin are separated, and FIG. 5 is a perspective view of the stopper pin.

In the drawing, A indicates the entire auto tensioner, 1 is a support shaft, 2 is an arm, 3 is a tension pulley, 4 is a torsion coil spring, and 5 is a friction plate. Also,
B is a belt wound around the outer periphery of the tension pulley 3.

The illustrated auto tensioner A has a structure in which a tension pulley 3 is arranged within the axial dimension of the support shaft 1.

The support shaft 1 includes an arm support portion 11, a cover portion 12, and a bolt mounting piece 13. The arm support portion 11 and the bolt mounting piece are mounted on an object to be provided with a belt drive mechanism (not shown). It is fixed by attaching a bolt (not shown) via the cable 13. The arm support portion 11 has a truncated conical outer peripheral surface on the distal half and a cylindrical outer peripheral surface on the proximal half. Cover part 12
Is formed so as to extend radially outward from the base end side of the arm support portion 11 and surround the outer periphery of the arm support portion 11. The bolt attachment piece 13 is formed to protrude radially outward on the outer periphery of the cover portion 12. The support shaft 1 is made of a cast product manufactured by die-casting using an aluminum alloy or the like, and the shape of the outer peripheral surface of the arm support portion 11 corresponds to the draft of the forming die.

The arm 2 is rotatably attached to the arm support 11 of the support shaft 1 and has a boss 21 at one end.
However, a pulley support portion 22 is formed at the other end. The boss portion 21 is rotatably fitted to the outer periphery of the arm support portion 11 of the support shaft 1 via the slide bearing 7. Pulley support 22
Are projectingly provided in the same direction as the projecting direction of the boss portion 21. The arm 2 is also made of a cast product manufactured by die-casting using an aluminum alloy or the like, like the support shaft 1. The above-described plain bearing 7 is formed in a truncated cylindrical shape, and is made of a bush whose thickness is gradually increased from a large diameter portion to a small diameter portion. Is formed.

The tension pulley 3 is rotatably supported by a pulley support portion 22 of the arm 2 via a rolling bearing 9 and is made of a press material. The tension pulley 3 is attached to the pulley support portion 22 of the arm 2 by bolts 8a screwed thereto so as to prevent the pulley 3 from coming off. In addition, the above-mentioned rolling bearing 9 includes the tension pulley 3
Of the arm 2 and the outer peripheral surface of the pulley support portion 22 of the arm 2 in a press-fit state.

The torsion coil springs 4 are respectively provided in annular spaces between the outer peripheral surface of the arm supporting portion 11 of the support shaft 1 and the outer peripheral surface of the boss portion 21 of the arm 2 and the inner peripheral surface of the cover portion 12 of the support shaft 1. It is arranged in a state of being torsionally compressed without contact with the surface. The torsion coil spring 4 urges the arm 2 in one rotation direction (counterclockwise in FIG. 1) by the torsion restoring force, and frictionally bosses 21 of the arm 2 by the axial extension restoring force. The boss 21 is pressed against the plate 5 to provide frictional resistance. At both ends of the torsion coil spring 4, bent portions 4 bent outward in the radial direction are provided.
1, 42 are provided integrally, and these bent portions 4
The slits 1 and 42 are engaged with a slit-shaped notch 14 provided at the bottom of the support shaft 1 and a slit-shaped notch 23 provided at the boss 21 of the arm 2, respectively.

The friction plate 5 is provided between the front end surface of the boss 21 of the arm 2 and the friction plate pressing plate 6 fixed to the tip end of the arm support 11 of the support shaft 1. The boss portion 21 is extended by the extension restoring force of the torsion coil spring 4.
The boss portion 21 of the arm 2 is pressed against the boss portion 21 of the arm 2 by a required pressure against the boss portion 21 and the friction plate pressing plate 6. In addition, the above-mentioned friction plate pressing plate 6
For example, it is formed by press forming a rolled steel sheet for a structure. The center hole of the friction plate pressing plate 6 and the support shaft 1
As shown in FIG. 1, the outer peripheral surface of the tip of the arm support portion 11 is formed into a sinusoidal wavy shape, and the friction plate pressing plate 6 is prevented from rotating by their fitting,
The distal end of the arm support portion 11 is plastically deformed by caulking to expand the diameter, thereby preventing the friction plate pressing plate 6 from coming off.

In the automatic tensioner A described above, the movement of the tension pulley 3 according to the fluctuation of the tension and relaxation of the tension of the belt B is allowed while the vibration and impact from the belt B are attenuated. Has the function of regulating movement.

That is, an operation when the tension of the belt B changes relatively slowly will be described. When the tension of the belt B gradually decreases, the arm 2 and the tension pulley 3 tilt to the left in FIG. 1 by the torsion restoring force (urging force in the circumferential direction) of the torsion coil spring 4, and the tension of the belt B is kept constant. Dripping. On the other hand, when the tension of the belt B gradually increases, the arm 2 and the tension pulley 3 tilt to the right in FIG. 1 against the torsion restoring force of the torsion coil spring 4, and the tension of the belt B is kept constant. . The change in the tension of the belt B occurs due to a change in the temperature of the environment, a change in expansion and contraction over time, and the like.

When severe vibration or impact is applied to the auto tensioner A from the belt B, the vibration or impact is transmitted to the boss 21 of the arm 2 supporting the tension pulley 3. Since the boss portion 21 of the arm 2 is pressed against the friction plate 5 by the extension restoring force (biasing force in the axial direction) to generate frictional resistance, vibrations and shocks are absorbed and attenuated. Suppress unnecessary swing. Thereby, the tension pulley 3
Does not substantially change, and the tension with respect to the belt B is kept constant.

Here, the features of the present invention will be described. In order to regulate the swing range of the arm 2, a range regulating portion is provided on the support shaft 1, and a stopper pin 26 is provided on the arm 2. In other words, at two locations on the outer periphery of the arm support portion 11 of the support shaft 1 that are separated in the circumferential direction, the convex wall portions 15 and 16 that protrude outward in the radial direction are provided as range control portions. A tongue piece 24 is provided on the outer periphery of the boss 21 of the arm 2 so as to protrude radially outward. The tongue piece 24 is provided with a hole 25 penetrating in the axial direction.
5, a stopper pin 26 is mounted by press-fitting. The stopper pin 26 is formed of a split pin having a substantially C-shaped cross section obtained by separating a part of the circumference, and is formed of a metal material having a spring property, for example, JIS standards S60C, S70C, SK5, or the like. In this embodiment, the holes 25
The inner peripheral surface is formed such that a region of about 1/3 in the axial direction is formed as a cylindrical surface, and the remaining approximately 2/3 is formed as a tapered surface whose diameter increases outward. Is set to be as large as possible. Further, both ends in the longitudinal direction of the outer peripheral surface of the stopper pin 26 are chamfered so that the stopper pin 26 can be easily attached to the hole 25.

A stopper pin 26 provided on the arm 2 is arranged in an inner space sandwiched between the two convex walls 15 and 16 provided on the support shaft 1. As a result, the stopper pin 26 moves around the arm supporting portion 11 of the support shaft 1 with the swing of the arm 2, but the two convex wall portions 15 and 16
Accordingly, the range of movement of the stopper pin 26 is restricted.

As described above, while adopting the simple form of press-fitting the stopper pin 26 into the hole 25, the outer peripheral surface of the stopper pin 26 and the inner peripheral surface of the hole 25 are formed by using the stopper pin 26 as a split pin. Thus, it is not necessary to perform another processing such as polishing, thereby preventing the manufacturing cost from increasing as in the conventional example. Stopper pin 2
Although 6 is a split pin, the stopper pin 26 is elastically restored after the press-fitting into the hole 25 because it is formed of a material having a spring property by itself, and the press-fit margin is held. Therefore, even if vibration is repeatedly applied to the auto tensioner A, the stopper pin 26 does not easily come off.

It should be noted that the present invention is not limited to only the above-described embodiment, and various applications and modifications are conceivable.

(1) In the above embodiment, an example is given in which the inner peripheral surface of the hole 25 provided in the boss portion 21 of the arm 2 is formed into a cylindrical surface and a tapered surface for each region. The shape of the surface may be a tapered surface only as shown in FIG. 6, or a cylindrical surface (not shown). When the inner peripheral surface of the hole 25 is only a tapered surface as shown in FIG. 6, a cut-and-raised piece (not shown) or the like is provided on a part of the outer peripheral surface of the stopper pin 26, and after the press-fitting mounting. It is also possible to strengthen the retaining.

(2) In the above embodiment, the structure in which the tension pulley 3 is disposed within the axial dimension of the support shaft 1 is taken as an example, but the tension pulley 3 projects forward from the tip of the support shaft 1. The present invention can also be applied to a structure in which the components are arranged.

(3) In the above embodiment, the sliding bearing 7
Although the thickness is varied in the axial direction as an example, the thickness can be made uniform. The material of the sliding bearing 7 may be any material having the required sliding properties, load resistance and wear resistance, and may be various synthetic resin materials or metal materials.

[0030]

In the automatic tensioner according to the first and second aspects of the present invention, a structure in which the stopper pin is mounted by press-fitting into a hole provided in one of the support shaft and the arm is adopted. In addition to avoiding such complicated mounting work, the outer peripheral surface of the stopper pin and the inner peripheral surface of the mounting hole for the stopper pin are formed by separating the stopper pin from a part of the circumference. Processing such as polishing of the surface can be omitted, so that manufacturing costs can be reduced.

As described above, according to the present invention, it is possible to provide an excellent auto tensioner having an arm swing range restricting structure which is inexpensive and can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a front view of an auto tensioner according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is a perspective view of a part of the auto tensioner of FIG. 1;

FIG. 4 is a view showing a state where a boss portion and a stopper pin of the arm of the embodiment are separated.

FIG. 5 is a perspective view of the stopper pin of the embodiment.

FIG. 6 is a view corresponding to FIG. 4 in another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List A auto tensioner B belt 1 support shaft 11 arm support portion 15, 16 convex wall portion of arm support portion (range regulating portion) 2 arm 21 arm boss portion 22 pulley support portion 24 boss portion tongue piece 25 tongue piece Hole 26 Stopper pin attached to hole 3 Tension pulley 4 Torsion coil spring 5 Friction plate

Claims (2)

[Claims] 1. An arm having a tension pulley rotatably supported on the other end while one end is rotatably supported on a fixed support shaft, and for restricting a swing range of the arm. The stopper pin and the range restricting portion are separately provided for the support shaft and the arm, and the stopper pin is a split pin that is partially separated on the circumference, and is press-fitted into a hole provided in the mounting target member thereof. An auto-tensioner to be mounted. 2. The auto-tensioner according to claim 1, wherein the stopper pin is provided on an outer periphery of a rotation support portion with respect to a support shaft of the arm, and a range restricting portion is provided on an outer periphery of the support shaft, respectively. On the outer periphery of the rotation support portion, a tongue piece projecting outward in the radial direction is provided, and a hole penetrating in the axial direction is provided in the tongue piece, and the stopper pin is press-fitted into this hole. In two places circumferentially separated on the outer periphery of the support shaft,
An auto-tensioner, wherein a convex wall protruding radially outward is provided as a range restricting portion, and a stopper pin is arranged in an inner space sandwiched between the two convex walls.