JPS6267357A - Intermediate pulley for endless driving belt - Google Patents

Abstract

PURPOSE:To obtain the good follow-up property of a belt for a rapid change of its load and to suppress a change of tension of the belt to a minimum limit, by interposing a resilient member in the peripheral surface of a bearing supporter fixed to a supporting bed and fitting a fixed ring of a rolling bearing to said member. CONSTITUTION:A pulley, fixing a bearing supporter 10 to a supporting bed 40 by a bolt 17, interposes a resilient member 30, forming sprig steel to a corrugated ring-shaped unit, in the peripheral part of the bearing supporter 10 to be fitted with an inner ring 21 of a ball bearing 20. And the pulley, fitting resin made or metallic sliding plates 25, 26 to a part between end surfaces of the inner ring 21 and a retaining plate 10a and a cover 14 fixed to the bearing supporter 10, is enabled to move in the radial direction. Accordingly, if tension of a belt increases due to a rapid change of load, the pulley, moving the ball bearing in the radial direction against repulsive force of the resilient member 30, relaxes an increase of tension. If the tension decreases due to a rapid decrease of load, the resilient member 30 performs a follow-up movement in the radial direction by restoring force internally existing when the initial tension is set.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an intermediate pulley of an endless drive belt, and in particular, a method for minimizing changes in belt tension by quickly following changes in belt tension. This is what I did.

[Conventional technology]

Conventionally, this type of intermediate pulley has been used as a tensioner for, for example, a timing belt for driving a camshaft of a vehicle engine or a belt for driving other auxiliary equipment. This tensioner is attached to the engine block on the slack side of the timing belt, which is stretched endlessly between the timing pulley on the crank side and the timing pulley on the camshaft side, and is set to a predetermined initial tension (for example, 20 ~30 kgf) to prevent tooth skipping from occurring between the timing belt and the timing belt that meshes with it.

Tensioners of this type are known, particularly fixed tensioners and automatic tensioners.

The fixed tensioner has a structure in which the inner ring of the τ roller bearing is fitted onto the outer peripheral surface of the bearing carrier, and one end of the torsion coil spring is fixed to the engine block, and the other end is fixed to the bearing carrier. 4. With the bearing carrier rotated and torsional force applied to the torsion coil spring, the bolt inserted into the eccentric bolt hole of the bearing carrier is inserted. (1, G, N, 2) Fix it at 0, and give the timing belt an initial tension of 4''.

Self-e type tenjiwo) (-toshishi, L, for example, West German public release 1
ζ；'Approval No. 2524-/44 '6 Publication・)）S is known, and for a tightening member that fixes the inner ring of a rolling bearing to a fixed housing with a tightening bolt. Eccentricity, seven people - keep you spinning 'ill,
Among these, 1.'' between 11 (eccentric wheel) and tightening A.1 member.
The fixed torsion coil and 1' spring 6 bring the eccentric wheel into contact with the belt at an appropriate rotational position to apply initial tension, and when the tension of the belt fluctuates, the torsion coil spring
By rotating the eccentric wheel, the belt tension is automatically adjusted by 8j, and the rotation angle of the eccentric wheel relative to the tightening member is set on either the tightening member or the eccentric wheel. This is done by sliding a stopper pin on the other side in a groove.

[Problem that the invention seeks to solve]

The fixed tensioner mentioned above operates normally at room temperature, but when the temperature changes, due to the difference between the engine block and the timing belt, the following A problem occurs. For example, the net expansion coefficient of one aluminum engine brake is 24.
x 10-'', ''c, but since the linear expansion coefficient of the timing belt with reinforcing wire is 6X10-'/''C, the engine speed is lower than that of the timing belt at low temperatures. Because the belt is thicker (contracts), the distance between the timing pulleys shortens and the belt loosens1, which increases belt vibration and may cause tooth skipping. On the contrary, at high temperatures, the elongation between the timing pulleys is greater than the elongation of the timing belt, and the belt tension increases (for example, under operating conditions of about 80°C, the belt tension increases by about 20 kgf). , the durability of the belt will be reduced.

On the other hand, automatic tensioners do not suffer from the above-mentioned problems due to temperature changes;
, or the ral between the bell (- and the timing pulley)
When the tension of the belt on the loose side increases and the tensioner receives a large load, such as when a foreign object gets caught in the belt, tighten the tightening member at positions I and J by the amount corresponding to the balance of the loader. Centered at 7, turn rapidly and sensitively i1),
Because it is not able to follow the movement of the belt when it is thrown off by the belt and suddenly loosens, the belt vibrates every time the belt is loosened, which causes the tooth skipping phenomenon to occur. . There is a problem that the tooth skipping phenomenon is particularly likely to occur when the engine is started at low temperatures (,7,-', when the tension of the lever 1 is low).

As for the automatic tensioner function of L-; If you use a torsion coil spring, it will be possible to maintain the specified tension during sudden load changes.): i) J::
In this case, it is necessary to prevent sudden vibrations of the belt using a torsion coil spring with high rigidity.

However, the same torsion coil spring cannot simultaneously satisfy these contradictory conditions.

Therefore, with conventional automatic tensioners, even if 7 is sufficient for the initial tension, it is not possible to obtain the necessary and sufficient followability to minimize changes in belt tension during sudden load changes. It turns out.

In addition to the above-mentioned intermediate pulley used as a tensioner, there is also an intermediate pulley (idler) used to simply adjust the tension of the belt against drastic load fluctuations, as described above. There is a problem.

This invention 4j2 solves the above problems and provides an intermediate pulley that can quickly follow changes in belt tension and has a function of suppressing tension changes to a minimum. Purpose and r.

Means for Solving Problems r] The intermediate block of the present invention is 1, d) between the fixed ring of the hinged bearing and the bearing i1 body. Please provide it with an elastic member interposed.

[Effect]

When the intermediate boot is subjected to a load due to a sudden increase in belt tension, the rolling bearing moves in the radial direction against the repulsive force of the elastic member, and when the load returns to normal, it immediately moves due to the restoring force of the elastic member. It returns to its original position.

In addition, if the load is reduced due to a sudden decrease in tension, the elastic member is already deformed by the initial tension when setting the initial tension on the intermediate pulley, so even if the tension decreases, the intermediate pulley will not be present. The restoring force in the radial direction (
Follow this movement.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of a tensioner.

In the figure, reference numeral 10 indicates a hollow circular bearing carrier 7 consisting of a small diameter part 11 and a large diameter part 12, and the open end on the large diameter part side is placed on a support base 40 such as engineered flock. A lid 14 is placed over the bottom 13 of the small diameter portion of the abutted side, and a port 17 is inserted into the eccentric bolt hole between the bottom 13 and the lid 14.
is screwed onto the support base 40 and fixed thereto.

The inner ring 21 of the ball bearing 20 is fitted as a fixed ring onto the outer peripheral surface of the small diameter portion 11 of the bearing carrier 10 with an elastic member 30 interposed therebetween. The inner ring 21 has balls 2 as rolling elements.
An outer ring 23 is rotatably assembled with the outer ring 2 interposed therebetween. A collar portion 24 extends on the axial side of the outer ring 23, and an endless drive belt (not shown) contacts the outer peripheral surface of the outer ring 23 to rotate it.

Resin or metal sliding plates 25 and 26 are fitted between the axially opposite end surfaces of the inner ring 21 of the ball bearing 20, the step surface of the bearing carrier 10, and the side surface of the lid 14, respectively.

By configuring as described above, the ball bearing 20 can be assembled in such a manner that it can move in the radial direction against the elastic repulsive force of the elastic member 30 interposed between the inner ring 21 and the bearing carrier 10.] Although this means that the movement in the axial direction and the corner
This means that it is regulated by the stepped surface of the bearing carrier 10 and the side surface of M14.

When attaching the above tensioner to the support base 40, insert the torsion coil spring 32 inside the bearing carrier 10,
After fixing the leg 33 at one end of the torsion spring 32 to the hole 41 of the support base 40 and inserting the leg 34 at the other end into the hole penetrating the side plate 13 and M14 of the bearing carrier 10, Rotate the tensioner by an appropriate angle to twist the coil spring 32.
Twist and screw the bolt 17 into the support base 540 so that it is in contact with the belt and fix it. As a result, the outer ring 23 of the ball bearing 20 comes into contact with an endless drive belt (not shown).
During the operation of the endless drive belt, in which a predetermined initial tension is applied to the
For example, when the belt tension increases and the tensioner receives a large load, the ball bearing 20 resists the repulsive force of the elastic member 30 and moves in the radial direction C. When the load returns to normal, the ball bearing 20 returns to its original position due to the warp of the elastic member 30.

In addition, if the L load is reduced due to a sudden decrease in tension, the elastic member is already deformed by the initial tension when setting the initial tension of the intermediate boob, so even when the tension decreases, the intermediate The pulley follows the movement in the radial direction due to its inherent restoring force.

In this way, since the elastic member 30 has the function of causing the tensioner to follow the movement of the belt due to rapid load changes, changes in belt tension are suppressed to the minimum range.

When the tensioner receives a large load, the inner ring 21 of the ball bearing 20 has its axially opposite end surfaces pressed against the sliding plates 25 and 26.
7, so movement in the radial direction is carried out smoothly, and furthermore, movement in the axial direction/＼ and angular wobbling are restricted.

2 and 3 show other embodiments of the tensioner. In this embodiment, a bracket 1 is attached to the outer periphery of the four-bearing carrier 10.
8 and then attach the lower end 18a of the bracket] 8 to the bin 1.
9 to rotate freely (= attached to the support stand 40, hang the hook at one end of the tension spring 35 on the upper end 18b of the bracket 18, and then attach the hook to the support stand 4).
It seems to be stuck at 0.

The bearing carrier 10 is fixed to the support base 40 by inserting a bolt 17 through its center. The bolt hole of the bearing carrier 10 has an arc-shaped groove 15 cut in both the left and right sides thereof, and the bolt hole of the lid 14 also has a groove 16 of the same shape.
These grooves 15 and 16 are overlapped and matched.

This tensioner fixes the bearing carrier 10 to the support base 40 with the bolt 17 at its center position, then pulls the tension coil spring 35 to move the bearing carrier 10 onto the bracket 18.
By rotating the belt around the pin 19 at the lower end 18a of the belt, a predetermined initial tension is applied to the belt.

The configuration j2 other than the above is the same as the embodiment shown in FIG. 1, and the operation is also the same, so the same parts are denoted by the same reference numerals and repeated explanation will be omitted.

FIG. 4 is a longitudinal sectional view showing an embodiment of the idler.

The difference from the bearing carrier 3F- in FIG. a presser plate 10a that regulates the
Also, the torsion coil spring that provides the initial tension is omitted, and the other configurations are the same as in FIG. 1, so the same parts are denoted by the same reference numerals and repeated explanations will be omitted.

According to the idler having the above configuration, when a load fluctuation occurs during operation of the endless drive belt, the follow-up function by the elastic member 30 can be obtained as in the case of the tensioner.

5 to 7 show preferred embodiments of the elastic member of the present invention.

The elastic member shown in FIG. 5 is formed from spring steel into a corrugated ring-shaped body. This spring is not limited to a continuous ring-shaped body such as an oral tradition, but may be a discontinuous ring-shaped body by cutting at one place.

The strength and expansion/contraction stroke of this spring shall be appropriately selected depending on the maximum load of the endless drive belt used.

The elastic member shown in FIG. 6 is made of rubber or other rubber-like elastic body formed into a ring-shaped body, and the outer surface thereof has a seventh ring.
A triangular recess 31 parallel to the width direction is formed as shown in the figure. This recess 31 may be formed on the inner circumferential surface, or may be formed on both the outer circumferential surface and the inner circumferential surface.
．． ．． May be 5. The shape of the four parts 31 is not limited to a triangular shape, and any shape such as a quadrangular shape or a semicircular shape can be selected.

The hardness of the material of this elastic body and the shape and size of the recessed portion are appropriately selected depending on the conditions of use.

〔Effect of the invention〕

As explained above, according to this invention, an elastic member is interposed on the outer peripheral surface of the bearing carrier of the intermediate pulley of the endless drive belt, and the fixed ring of the -1 rolling bearing is fitted. The ability of the belt to follow rapid load changes is improved quickly, and it becomes possible to minimize changes in belt tension.

Therefore, if the intermediate boom of the present invention is applied to the timing held tensioner, the belt tension adjustment function during load fluctuations can be obtained by an elastic member that is separate and independent from the spring that applies the initial tension. The effect of preventing the tooth skipping phenomenon caused by the wave motion can be achieved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a tensioner, FIG. 2 is a longitudinal sectional view showing another embodiment of the tensioner, FIG. 3 is a front view thereof, and FIG. 4 is a longitudinal sectional view showing another embodiment of the tensioner. FIG. 5 is a front view showing an embodiment of the elastic member; FIG. 6 is a front view showing another embodiment of the elastic member; FIG. 7 is a sectional view taken along the line A--A in FIG. 6. In the figure, 10 is a bearing carrier, 20 is a ball bearing, 21 is an inner ring, 2
2 It5, 23 is an outer ring, 30 is an elastic member, and 40 is a support base. Patent Applicant NSK Co., Ltd. Agent Patent Attorney Tetsuya Mori Patent Attorney Yoshiaki Naito Agent Patent Attorney Tadashi Shimizu Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) In an intermediate pulley for an endless drive belt, which includes a bearing carrier fixed to a support base, and a rolling bearing in which a rotating ring is assembled with a rolling element interposed in a fixed ring fitted to the outer peripheral surface of the bearing carrier. An intermediate pulley for an endless drive belt, characterized in that an elastic member is interposed between the bearing carrier and the fixed ring of the rolling bearing. (2) The intermediate pulley for an endless drive belt according to claim 1, wherein the elastic member is a spring formed into a corrugated ring-shaped body. (3) The endless drive belt according to claim 1, wherein the elastic member is a rubber-like elastic body in which a recess is formed in parallel to the width direction of at least one of the outer circumferential surface and the inner circumferential surface of the ring-shaped body. Intermediate pulley for use.