JPH11118007A - Belt tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure for making the outside dimension of an entire body compact with the smallest possible number of parts. SOLUTION: In a belt tensioner A, a rotatable tension pulley 1 can freely swing about a position deviated from the center of its rotation as a supporting point. A tension adjusting means for switching the tension pulley 1 so as to maintain the constant tension of a belt 80 and a damper means 4 for damping vibration or impact transmitted from the belt 80 are provided in parallel along the axial direction of a swinging in the side of the tension pulley 1. Thus, the outside dimension of the tension pulley 1 can be reduced. Further, the tension energiging movable member of the tension adjusting means and the load transmitting movable member 48 of the damper means 4 can respectively abut on a single protruding part 18 provided on the tension pulley 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tensioner for adjusting the tension of a belt, such as a timing belt and an auxiliary device driving belt provided in an automobile engine.
Specifically, the configuration is such that the rotatable tension pulley can swing about a position eccentric from the rotation center as a fulcrum,
The present invention relates to a belt tensioner having a function of swinging a tension pulley so as to keep a belt tension constant and a function of attenuating vibration and impact transmitted from the belt.

[0002]

2. Description of the Related Art In general, the belt tension may change due to a change in the center-to-center distance between pulleys and a torque fluctuation due to thermal expansion of an automobile engine. A belt tensioner that prevents such a change in belt tension and keeps it constant has been considered. An example of this conventional belt tensioner is disclosed in Japanese Patent Publication No. 5-2852.

As shown in FIG. 6, the belt tensioner has a structure in which a rotatable tension pulley 90 can be swung about a position 91 eccentric from the center of rotation thereof as a fulcrum, and the tension of the belt 92 is kept constant. As described above, the direct-acting actuator 93 having not only the function of swinging the tension pulley 90 but also the function of attenuating the vibration and impact transmitted from the belt 92 is provided.

As shown in FIG. 7, a direct-acting actuator 93 includes a case 94 serving as a cylinder and a case 94.
The two liquid chambers 95 and 9 are slidably housed inside the
6, a check valve 98 provided on the piston 97 to control the movement of hydraulic oil between the liquid chambers 95 and 96, a push rod 99 attached to the piston 97, and hydraulic oil from the case 94. The structure is such that a cylindrical coil spring 101 for adjusting tension is added to a general oil damper mechanism including a diaphragm seal 100 for preventing leakage of the oil.

[0005]

By the way, in the above-mentioned conventional belt tensioner, means for swinging the tension pulley 90 so as to keep the tension of the belt 92 constant,
Although a direct-acting actuator 93 is used in which the means for attenuating vibrations and shocks transmitted from the belt 92 are used, this direct-acting actuator 93 has a relatively long structure with a configuration as shown in FIG. Therefore, the belt tensioner has to be enlarged, for example, it is protruded beyond the outer diameter of the tension pulley 90.
For this reason, when the installation space is restricted due to the layout of the belt tensioner and other members in relation to the layout of other members, the belt tensioner cannot be installed due to interference with other members provided in the installation target, or other It is pointed out that the interval between the members becomes too small and maintenance becomes difficult.

In order to reduce the length of the linear actuator 93, for example, a coil spring 101 is used.
May be shortened or the liquid chambers 95 and 96 may be shortened. However, the required performance may not be satisfied, and such a design change is impossible.

In order to solve such a problem, the applicant of the present application has proposed the one shown in Japanese Patent Application No. 8-290041.

According to the present invention, in the linear actuator of the prior art, the tension adjusting means for keeping the tension of the belt constant and the damper means for attenuating the vibration and impact transmitted from the belt are separated, and they are connected to the side of the tension pulley. Are arranged in parallel on the same plane. However, in this case,
It is necessary to make the movable member for tension urging of the tension adjusting means and the movable member for load transmission of the damper means individually contact two projections provided on the tension pulley in parallel with the pivot shaft. It is pointed out that there will be more.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to realize a structure for reducing the overall outer diameter of a belt tensioner with as few parts as possible.

[0010]

According to a first aspect of the present invention, there is provided a belt tensioner in which a rotatable tension pulley is swingable about a position eccentric from a center of rotation of the tension pulley. Tension adjusting means for swinging the tension pulley so as to keep it constant, and damper means for attenuating vibration and impact transmitted from the belt, and these tension adjusting means and damper means are provided on the side of the tension pulley. They are provided in a state of being aligned along the swing axis direction.

[0011] The belt tensioner of claim 2 of the present invention comprises:
A rotatable tension pulley that applies tension to the belt, a fixed swing fulcrum shaft that swingably supports a position eccentric from the rotation center of the tension pulley, and a position eccentric from the rotation center of the tension pulley A single protrusion integrally provided in parallel with the pivot axis, tension adjusting means for swinging the tension pulley so as to keep the tension of the belt constant, and vibration and impact transmitted from the belt to the tension pulley. Damper means for attenuating the tension, and the tension adjusting means and the damper means are provided side by side along the tension pulley along the direction of the swing axis thereof. The tension biasing movable member and the load transmitting movable member of the damper means are in contact with the single convex portion, respectively.

[0012] The belt tensioner of claim 3 of the present invention comprises:
A rotatable tension pulley that applies tension to the belt, a fixed swing fulcrum shaft that swingably supports a position eccentric from the rotation center of the tension pulley, and a position eccentric from the rotation center of the tension pulley A single protrusion integrally provided in parallel with the pivot axis, tension adjusting means for swinging the tension pulley so as to keep the tension of the belt constant, and vibration and impact transmitted from the belt to the tension pulley. Damper means for attenuating the tension, and the tension adjusting means and the damper means are independent from each other in a single case fixed with respect to the pivot axis of the pivot in the direction of the pivot axis of the tension pulley. And the movable member for tension biasing of the tension adjusting means and the movable member for load transmission of the damper means are arranged with respect to the single convex portion. Re is in contact.

[0013] The belt tensioner of claim 4 of the present invention comprises:
The tension adjusting means according to any one of claims 1 to 3 is disposed closer to the tension pulley than the damper means, and the tension adjusting means is inserted into the inner peripheral side of the tension pulley.

In short, according to the first to third aspects of the present invention, the separate tension adjusting means and the damper means are provided on the side of the tension pulley along the direction of the swing axis so that the entire belt tensioner is provided. The outer diameter can be reduced. Moreover, with such an arrangement, the movable member for tension biasing of the tension adjusting means and the movable member for load transmission of the damper means can be brought into contact with a single convex portion provided on the tension pulley. This makes it possible to eliminate the need for providing a plurality of the convex portions as in the conventional example.

In particular, according to the third aspect of the present invention, the tension adjusting means and the damper means are housed independently in a single case, so that the assembling work can be performed more easily than when they are housed in separate cases. ing.

According to the fourth aspect of the present invention, since only the damper means projects to the side of the tension pulley, the axial width of the entire belt tensioner can be reduced as in the conventional case.

[0017]

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

FIGS. 1 to 5 relate to an embodiment of the present invention. FIG. 1 is a view schematically showing a use state of a belt tensioner, and FIG. 2 is a plan view of the belt tensioner as viewed from above. 3 is an exploded perspective view of the belt tensioner as viewed from the back, FIG. 4 is a cross-sectional view taken along line (4)-(4) of FIG. 2, and FIG. 5 is (5) of FIG. It is an arrow view of the section of-(5) line.

In FIG. 1, reference numeral 80 denotes a belt, 81 denotes a pulley of a crankshaft, 82 denotes an idler pulley, 83 denotes an auxiliary pulley, and A denotes a belt tensioner.

The belt tensioner A is mounted on a mounting object 85 such as a block of an automobile engine in order to apply a required tension to the belt 80. The belt tensioner A prevents a change in the tension of the belt 80 due to a change in environmental temperature and a change in torque. And a function of attenuating vibrations and shocks transmitted from the belt 80.

As shown in FIGS. 2 to 5, the belt tensioner A mainly includes a rotatable tension pulley 1 for applying tension to a belt 80 and a tension pulley 1 with respect to an object 85 to be mounted. A swing fulcrum shaft 2 that oscillates at an eccentric position as a fulcrum, and a tension pulley 1 that keeps the tension of the belt 80 constant.
Adjusting means 3 for oscillating the shaft, damper means 4 for attenuating vibrations and shocks transmitted from the belt 80, and tension adjusting means 3 and damper means 4 which are fixed to the side of the oscillating fulcrum shaft 2.
And a single case 5 which is stored and arranged in a state of being arranged along the swing fulcrum shaft 2.

The tension pulley 1 is formed integrally with a ball bearing, and includes an inner race 11, a wide outer race 12 serving as a pulley around which a belt 80 is wound, and inner and outer races 11, 1.
A plurality of balls 13 interposed between the two, a crown-shaped retainer 14 holding the balls 13, seals 15, 15 provided on both axial sides between the inner and outer rings 11, 12, and an inner periphery of the inner ring 11 And a boss 16 which is press-fitted into the boss. The boss 16 is provided with a through hole 17 at a position eccentric from the center thereof, and a pin 18 is planted at a position separated from the through hole 17 by a required distance.

The swing fulcrum shaft 2 is composed of a bolt or the like, and is implanted into the mounting object 85 via the boss 16 of the tension pulley 1 and the case 5.

The tension adjusting means 3 urges the tension pulley 1 around the pivot shaft 2 in one rotation direction, and comprises a cylindrical coil spring 31 and a spring seat 32. The spring force of the coil spring 31 is
As shown in FIGS. 1A and 1B, it is set appropriately according to the layout of the belt 80 and the like.

The damper means 4 attenuates vibrations and shocks transmitted from the belt 80 to the tension pulley 1, and is housed in one of the long holes 52 of the case 5 described below to form two liquid chambers 46 and 47. Piston 4 with rod
A check valve 42 disposed on the piston 41 to control the movement of hydraulic oil between the liquid chambers 46 and 47; a cylindrical coil spring 43 for urging the piston 41 upward; A seal ring 44 for preventing leakage of hydraulic oil in 46 and 47, and one long hole 52 of the case 5 described below.
And a cover ring 45 for closing the opening of the cover.

The case 5 has two parallel long holes 51 and 52 adjacent to each other, a shaft insertion hole 53 through which the swing fulcrum shaft 2 is rotatably inserted through the collar 6, and a mounting object 85. And a mounting piece 54 fixed by a bolt or the like. The case 5 includes a liquid chamber 4 above the damper 4.
6 is provided with a large-capacity hydraulic oil storage chamber 55 that is connected to and connected to the hydraulic oil storage chamber 6. By providing such a large-capacity hydraulic oil storage chamber 55, it is possible to prevent the occurrence of cavitation during the damping operation of vibration and impact, and to achieve the long-term stabilization of the damping operation.

In the elongated holes 51 and 52 of the case 5, the tension adjusting means 3 and the damper means 4 are individually accommodated. Among these, the tension adjusting means 3 is a coil spring 3 housed in a compressed state in one long hole 51 of the case 5.
The spring seat 32 is pressed against the pin 18 located on the opening side of the elongated hole 51 by the elastic restoring force of 1. Further, the damper means 4 pushes the push rod 48 of the piston 41 by the extension restoring force of the coil spring 43 housed in the other long hole 52 of the case 5.
Is pressed against the pin 18 located on the opening side of the other long hole 52. One of the long holes 51 in which the tension adjusting means 3 is housed is formed in a rectangular tube shape, one side wall of which is removed and opened, and the arrangement of the two long holes 51 and 52 in the case 5. The dimension in the direction is set to be as short as possible. The portion where the one long hole 51 is formed is fitted into the recess 19 provided in the boss 16 in a non-contact manner, and the open portion of the one long hole 51 is closed by the inner surface of the recess 19 of the boss 16. Become

By the way, in the belt tensioner A of the above-mentioned embodiment, in order to easily attach the tension pulley 1 to the installation object 85, the belt tensioner A prevents the relative rotation between the tension pulley 1 and the case 5 before the attachment to the installation object 85. Stop pins 20 are removably inserted into respective holes (symbols omitted) provided in both the tension pulley 1 and the case 5. The detent pin 20 is removed after attaching the belt tensioner A to the installation target.

Next, the operation of the belt tensioner A will be described. First, as the environmental temperature rises,
Expands, the tension of the belt 80 tends to increase.
1 is contracted and the check valve 4 of the damper means 4
2 is closed, and while the oil gradually moves from the liquid chamber 47 to the liquid chamber 46 through a small gap between the piston 41 and the case 5, the tension pulley 1 rotates so as to retreat in the arrow Y direction in FIG. Then, the tension pulley 1 stops at a position where the excessive tension of the belt 80 is reduced and the tension of the belt 80 and the spring force of the coil spring 31 are balanced. In this way, the tension of the belt 80 is kept constant.

On the other hand, when the mounting object 85 contracts due to a decrease in the environmental temperature, the tension of the belt 80 tends to decrease. As a result, the coil spring 31 of the tension adjusting means 3 expands and the damper means When the check valve 42 is opened, the oil is moved from the liquid chamber 46 to the liquid chamber 47.
And the tension pulley 1 is rotated so as to advance in the direction of arrow X in FIG. 3, and the tension of the belt 80 and the coil spring 31 are adjusted so that the under tension of the belt 80 is maintained at an appropriate tension.
The tension pulley 1 stops at a position where the spring force is balanced. In this way, the tension of the belt 80 is kept constant.

Here, in any of the above states, the case 5 does not move and only the tension pulley 1 swings. When vibration and impact is applied to the tension pulley 1 from the belt 80, movement of the hydraulic oil in the liquid chambers 46 and 47 is prevented by the check valve 42 of the damper means 4, so that the vibration and impact are caused by the hydraulic oil. Damping suppresses instantaneous fluctuations in the tension of the belt 80 and prevents slippage of the belt 80.

As described above, the tension adjusting means 3 and the damper means 4 are housed in a single case 5 in a state of being arranged along the swing fulcrum shaft 2 on the side of the tension pulley 1 so that the tension can be adjusted. The pulley 1 is disposed so as to be substantially within the outer diameter of the pulley 1. For this reason, in particular, the radial dimension can be reduced as compared with the conventional example. In particular, in this embodiment, the tension adjusting means 3 is disposed so as to be accommodated in the inner periphery of the tension pulley 1 and only the damper means 4 is projected to one side of the tension pulley 1 in the axial direction. The axial width dimension of the entire auto tensioner A can be reduced to be equal to that of the conventional example.

Further, the spring seat 32 as a movable member for tension biasing of the tension adjusting means 3 and the push rod 48 as a movable member for transmitting load of the damper means 4 are formed as a single convex portion provided on the tension pulley 1. Since the pins 18 are brought into contact with the pins 18, respectively,
The number of parts and the number of assembling steps can be reduced, for example, by eliminating the need for providing a plurality of parts as in the prior art, which can contribute to cost reduction.

In addition, since the tension adjusting means 3 and the damper means 4 are separated from each other, for example, the adjustment range of the length dimension and the diameter dimension of the coil spring 31 constituting the tension adjusting means 3 is compared with the conventional example. Therefore, it is possible to set a wide range of tension according to a request based on the layout of the belt 80 and the like.

Further, since the damper means 4 is arranged at a position close to the pivot 2 of the tension pulley 1, the working stroke of the piston 41 can be shortened, which contributes to the reduction in size. In addition, the displacement of the contact position between the piston 41 and the pin 18 with respect to the swing amount of the tension pulley 1 can be reduced, and the vibration / impact load from the tension pulley 1 can be effectively attenuated.

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 described in which the tension pulley 1 is integrated with a ball bearing. However, a separate ball bearing is also included in the present invention.

(2) In the above-described embodiment, an example in which the tension adjusting means 3 and the damper means 4 are housed in a single case 5 has been described.

(3) In the above embodiment, a cylindrical coil spring is used for the tension adjusting means 3, but this can be replaced by an elastic biasing member such as a disc spring.

[0040]

According to the first to fourth aspects of the present invention, the separate tension adjusting means and the damper means are arranged side by side along the direction of the pivot axis on the side of the tension pulley. In addition to realizing compactness in directions, it can contribute to cost reduction.

Therefore, the belt tensioner of the present invention can be installed relatively easily even when the installation space in the radial direction is restricted due to the layout of the installation target and other members, and other belt tensioners can be installed. The degree of freedom in installation is increased, for example, a relatively large space between members can be secured. In addition, since the tension adjusting means and the damper means are separated, the permissible range of the dimensional change can be expanded, and the degree of freedom in design for required performance such as tension and damping force can be increased.

In particular, according to the third aspect of the present invention, the separate tension adjusting means and the damper means are housed next to each other in a single case, so that the assembling operation can be performed more easily than in the case where they are separated from each other. , And the assembly cost can be reduced.

According to the fourth aspect of the present invention, since only the damper means projects to the side of the tension pulley, the axial width dimension of the entire belt tensioner can be reduced as in the prior art, and eventually the belt tensioner can be reduced. Thus, the entire belt tensioner can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a use state of a belt tensioner according to an embodiment of the present invention.

FIG. 2 is a plan view of the belt tensioner of FIG. 1 as viewed from above.

FIG. 3 is an exploded perspective view of the belt tensioner of FIG. 1 when viewed from the back.

FIG. 4 is an arrow view of a cross section taken along line (4)-(4) in FIG. 2;

5 is a sectional view taken along line (5)-(5) of FIG.

FIG. 6 is a plan view of a conventional belt tensioner viewed from the back.

FIG. 7 is a cross-sectional view of a direct-acting actuator of the belt tensioner of FIG. 6;

[Description of Signs] A Belt tensioner 1 Tension pulley 16 Tension pulley boss 17 Boss through hole 18 Boss pin 2 Swing fulcrum shaft 3 Tension adjusting means 4 Damper means 5 Case 80 Belt 85 Installation target

Claims (4)

[Claims] 1. A belt tensioner having a structure in which a rotatable tension pulley can swing about a position eccentric from its rotation center as a fulcrum, wherein the tension pulley swings to maintain a constant belt tension. Tension adjusting means and damper means for attenuating vibrations and shocks transmitted from the belt, and these tension adjusting means and damper means are provided side by side of the tension pulley in a state of being aligned along the direction of the swing axis thereof. A belt tensioner. 2. A rotatable tension pulley for applying tension to a belt, a fixed swing fulcrum shaft swingably supported at a position eccentric from the rotation center of the tension pulley, and a rotation center of the tension pulley. A single protrusion integrally provided at a position eccentric from the shaft in parallel with the pivot shaft, tension adjusting means for swinging a tension pulley so as to keep the belt tension constant, and a tension pulley from the belt. And damping means for attenuating vibration and shock transmitted to the tension pulling means, and the tension adjusting means and the damping means are provided side by side with the tension pulley along the direction of the swing axis thereof, and The tension biasing movable member of the tension adjusting unit and the load transmitting movable member of the damper unit are in contact with the single convex portion, respectively.
A belt tensioner characterized in that: 3. A rotatable tension pulley for applying tension to a belt, a fixed swing fulcrum shaft pivotally supported at a position eccentric from the rotation center of the tension pulley, and a rotation center of the tension pulley. A single protrusion integrally provided at a position eccentric from the shaft in parallel with the pivot shaft, tension adjusting means for swinging a tension pulley so as to keep the belt tension constant, and a tension pulley from the belt. And a damper means for attenuating vibration and shock transmitted to the tension pulley, and wherein the tension adjusting means and the damper means are arranged in a single case fixed with respect to the pivot shaft, in the swing axis direction of the tension pulley. And the movable member for tension urging of the tension adjusting means and the movable member for load transmission of the damper means are the single unit. They are respectively abut against the part, a belt tensioner, characterized in that. 4. The belt tensioner according to claim 1, wherein the tension adjusting means is disposed closer to the tension pulley than the damper means, and the tension adjusting means is provided in the tension pulley. A belt tensioner characterized in that it is formed in a circumferential side.