JP3341515B2 - Auto tensioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An auto tensioner according to the present invention is a timing belt for an automobile engine or a belt for driving an auxiliary machine such as an alternator or a compressor (hereinafter, these are simply referred to as a "belt". It is used to give the proper tension to).

[0002]

2. Description of the Related Art In order to drive the camshaft of an OHC or DOHC engine in synchronization with a crankshaft, a driving device using a belt 1 as shown in FIG. 6 is widely used. In FIG. 6, reference numeral 2 denotes a driving pulley that is driven to rotate by a crankshaft of an engine, 3 denotes a driven pulley fixed to an end of a camshaft, and 4 and 4 guide the belt 1 or a water pump. Guide pulley or driven pulley for driving auxiliary equipment such as
This is a pulley for applying an appropriate tension to the pulley.

The pulley 5 is pivotally supported by a swing member 7 that swings about a pivot 6. A spring 8 is provided at an end of a bracket 7a fixed to the swing member 7,
By elastically pressing the pulley 5 toward the belt 1, the tension of the belt 1 is always maintained irrespective of the dimensional change of the belt 1 or the like due to a temperature change or the like, or the vibration accompanying the operation of the engine. I try to keep it constant.

[0004] By the way, a belt 1 is used for an auto tensioner.
In addition to the function of applying tension to the belt 1, a function of holding down the belt 1 is required. That is, in the camshaft driving device shown in FIG. 6, when the driving pulley 2 rotates, a portion of the belt 1 located between the pulleys 2 to 5
It tends to vibrate so as to swing in a direction perpendicular to the traveling direction. If this deflection is allowed as it is, the amplitude of the deflection increases (vibration grows), abnormal vibration occurs in the driving portion driven by the belt 1, or in the case of a toothed belt, so-called tooth jump occurs. Cause problems.

As an auto-tensioner for preventing such a problem, Japanese Patent Application Laid-Open No. 62-274143 and Japanese Utility Model Application Laid-Open No.
JP-A-52458 and the like describe an auto tensioner provided with a damper device. FIG. 7 shows a conventional auto tensioner equipped with such a damper device.

A swing member 7 supporting the pulley 5 is pivotally supported on a base such as a front surface of a cylinder block of the engine by a pivot 6. The pulley 5 has a pivot 6
It is freely rotatable about an axis parallel to the axis.
That is, an inner ring member 16 having a short cylindrical shape with a bottom, which is a support member described in the claims, is fixed to a tip portion of the swinging member 7 with a bolt 21 and a nut. The pulley 5 is rotatably supported around the inner ring member 16 via a plurality of balls.

[0007] Cylinder cylinder 9 constituting damper device 12
Is fixed to the base separately from the swinging member 7, and allows the hollow piston 15 to be displaceable in the viscous fluid sealed in the cylinder cylinder 9. This piston 15
A compression spring 11 is provided between one end face (lower end face in FIG. 7) and the inner end face (lower end face in FIG. 7) of the cylinder 9 and the other end face of the piston 15 (upper end face in FIG. 7) is provided. The base end (the lower end in FIG. 7) of the push rod 10 is connected. The distal end (the upper end in FIG. 7) of the push rod 10 abuts against a part of the swing member 7 so that the elastic force of the compression spring 11 can be transmitted to the swing member 7. Therefore, the pulley 5 is pressed against the belt 1 based on the elasticity of the compression spring 11. As described in Japanese Utility Model Laid-Open No. 52458/1985, a compression spring 11 in a damper device 12 is used.
In addition to the above, the swing member 7 may be provided with a spring.

On the other hand, a pair of chambers 17 and 18 located on both sides of the piston 15 communicate with each other through an oil passage 19 provided at the center between the piston 15 and the push rod 10. A check valve 20 is provided at the open end of the oil passage 19 and opens only when the viscous fluid flows toward the chamber 17 in which the compression spring 11 is provided.

In the case of the conventional auto-tensioner configured as described above, the push rod 10 is rapidly displaced in the protruding direction (upward direction in FIG. 7) and changes only slowly in the retracting direction (downward direction in FIG. 7). . For this reason, when the belt 1 is loose, the pulley 5 is quickly followed, and when the belt 1 is taut, the pulley 5 is held down without retracting. Therefore, the auto tensioner is
The tension of the belt 1 can always be kept constant irrespective of the temperature change, the dimensional change of the belt 1 due to the deterioration of the belt 1 or the like, or the vibration or the like accompanying the operation of the engine. In the case of the above-mentioned auto tensioner, the compression spring 11 constitutes the damper device 12 and also has a function of giving the resilient force in the direction of the pulley 5 toward the belt 1 to the swing member 7 as described above.

Incidentally, in order to make the tension of the belt 1 proper, it is necessary to make the tension (set tension) when the auto tensioner is assembled to the base proper. That is, when assembling the auto-tensioner to the base, the assembling position of the pulley 5 may be different from the design stage based on errors in the mounting dimensions and processing dimensions of the engine, the cylinder block, and the like. Since the spring constant of the compression spring 11 is determined according to the mounting position in the design stage, if the mounting position of the pulley 5 is different from that in the design stage as described above, the spring constant is determined to be appropriate. However, the tension of the belt 1 varies. In addition, when there is a large error in the mounting dimensions, processing dimensions, and the like, it is necessary to perform adjustment of each part at the time of assembly. If this adjustment operation is not performed, the stroke amount of the damper device 12 may be insufficient during engine operation, and the pulley 5 may not be able to follow a change in the tension of the belt 1.

However, in the case of the auto-tensioner shown in FIG. 7, the above-described adjustment work of the set tension is not considered. That is, the mounting positions of the swing member 7 and the damper device 8 are unified. Therefore, if there is an error as described above, the adjustment work cannot be performed,
Even if it can be done, it becomes extremely troublesome.

An auto-tensioner that eliminates such inconvenience and facilitates the work of adjusting the set tension has been conventionally known. For example, Japanese Utility Model Publication No. Hei 4-30450 discloses a structure in which a swinging member having a pulley and a damper device are provided on a single base plate. When assembling such an auto tensioner to a base, the set tension is adjusted by fixing the base plate to the base while rotating the base plate by a desired amount about a fulcrum. 5-2
Japanese Patent Application Publication No. 852 discloses a technique in which a pulley and a damper device (linear motion actuator) are integrally rotatable. Also in the case of this structure, when the auto tensioner is assembled to a base such as an engine, the set tension is adjusted by fixing the pulley and the damper device to the base while rotating the pulley and the damper device.

Further, Japanese Utility Model Publication No. Hei 4-30450 described above,
In addition, Japanese Utility Model Publication No. 4-255555 discloses a structure in which only the swing arm 13 is rotatable and the pulley 5 is eccentrically provided on the swing arm 13 as shown in FIG. I have. When adjusting the set tension of the auto tensioner having such a structure, the pulley 5 is rotated by a desired amount around an eccentric shaft 14 provided in parallel with the pivot 6. This changes the amount of protrusion of the pulley 5 in the belt 1 direction,
The belt 1 is fixed at a desired tension.

[0014]

In each of the above-described conventional auto tensioners, the set tension of the belt 1 can be set to a desired value. However, each of the above-described auto tensioners has the following disadvantages. That is, in the auto-tensioner described in Japanese Utility Model Publication No. 4-30450 and having a structure in which a swing member to which a pulley is attached and a damper device are provided on a single base plate, these swing members and A damper device should be provided,
A relatively large base plate is required. Since such a base plate is provided, the manufacturing cost increases. In addition, in order to make the base plate having such a large area rotatable, a large space must be secured in the assembly portion. Therefore, the space around the entire auto tensioner and the portion where the auto tensioner is assembled increases. In addition, the above-mentioned Tokuhei 5-2
In the auto-tensioner described in Japanese Patent Application Publication No. 852, in which the pulley and the damper device are integrally rotatable, a part for assembling the auto-tensioner in order to rotate the pulley and the damper device integrally. The space around the area increases.

Further, Japanese Utility Model Publication No. Hei 4-30450,
In the auto-tensioner described in Japanese Utility Model Publication No. 4-255555 having a structure in which a pulley is eccentrically provided on a swinging arm, the above-mentioned disadvantages do not exist, but the following disadvantages are used instead. Exists. That is, in this automatic tensioner, the pulley 5 is used to adjust the set tension.
Is rotated around the eccentric shaft 14 by a desired amount. When the pulley 5 is rotated around the eccentric shaft 14 in this manner, as shown in FIG. 9, the distance between the swing center (pivot 6) of the swing arm 13 and the center of the pulley 5 becomes What was L in
After the rotation, L ′ (L ≠ L ′). Swing arm 1
When the distance between the swing center of the pulley 3 and the center of the pulley 5 changes, the mechanical balance of the auto tensioner changes.
That is, when the distance between the swing center of the swing arm 13 and the rotation center of the pulley 5 changes, the leverage ratio of the force transmitted from the auto tensioner to the pulley 5 changes. As a result, the tension of the belt 1 changes. Note that FIG.
In FIG. 2, the state after the pulley 5 is rotated about the eccentric shaft 14 is illustrated with the swing arm 13 swinging, which makes it easier to see the distances L and L '. The swing arm 13 does not swing with the rotation of the pulley 5 about the eccentric shaft 14.

As described above, in the case of the auto tensioner having the structure in which the pulley 5 is eccentrically provided on the rotatable swing arm 13, the dimensional error of each component that causes a change in the tension of the belt 1 can be eliminated. Swing center of swing arm 13 and pulley 5
Of the belt 1 changes, and as a result, the tension of the belt 1 changes. That is, while trying to make the set tension proper when assembling the auto-tensioner, the set tension is eventually inappropriate. The auto-tensioner of the present invention has been made to solve any of the above-mentioned disadvantages.

[0017]

The auto-tensioner of the present invention has a first shaft supported by a base and a base end pivotally supported by the first shaft, similarly to the above-described conventional auto-tensioner. An oscillating member , a supporting member provided at a distal end of the oscillating member, the center axis of which is parallel to the first axis, and around the supporting member, the center axis of the supporting member is centered. A pulley rotatably supported, a spring for applying an elastic force in the direction of pressing the pulley toward the belt to the rocking member, and a damper for resisting displacement of the pulley against the elasticity of the spring Device. In particular, in the auto-tensioner of the present invention, at least one of the center portion of the support member and the tip portion of the swing member, an arc-shaped long hole centered on the first axis, A connecting and fixing member that is inserted through the elongated hole and is parallel to the first axis ;
It is fixed to the swing member .

[0018]

The function of the present invention configured as described above to press the belt with the pulley, to cause the pulley to follow the movement of the belt, and to suppress the vibration of the belt by the pulley is as described above. It is the same as that of the auto tensioner. In particular, in the auto tensioner of the present invention, the operation of adjusting the set tension of the belt can be easily and reliably performed by appropriately changing the mounting position of the supporting member to the swing member within the range of the length of the long hole. You. In addition, since this adjustment operation can be performed by relatively displacing the supporting member and the swinging member, the space around the installation portion does not increase. Further, since the elongated hole is formed in an arc shape about the first axis which is the swing center of the swing member, even when the mounting position of the pulley to the swing member is changed,
The center axis of the support member which is the rotation center of the first shaft and the pulley
The distance from the line does not change. Therefore, the mechanical balance of the auto tensioner does not change, and a desired set tension can be easily and reliably obtained.

[0019]

Next , an embodiment shown in the drawings will be described. FIG.
2 show the first embodiment of the present invention in which the present invention is applied to the auto tensioner shown in FIG. The same parts as those of the above-described conventional device are denoted by the same reference numerals, and redundant description will be omitted or simplified. Hereinafter, the description will be focused on the features of the present invention. As shown in FIG. 1, the pulley 5 is supported by a swing member 7 that swings around a pivot 6 that is a first shaft provided on a base such as the front surface of a cylinder block of the engine. The pivot 6 is composed of, for example, a bolt and a sliding bearing. The distal end (upper end in FIGS. 1 and 2) of the oscillating arm 13 continuing upward from FIG. 1 from the base end (lower end in FIG. 1) of the oscillating member 7 has a short bottom with a support member. The cylindrical inner ring member 16 is fixed by bolts 21 and nuts 22 which are connection fixing members . This bolt 21 is
It is parallel to the pivot 6 . The pulley 5 is rotatably supported around the inner ring member 16 via a plurality of balls 23.

The above configuration is the same as the conventional example shown in FIG. 7 described above. However, in the present invention, an arcuate shape centered on the pivot 6 is provided at the center of the inner ring member 16. The long hole 24 is formed. Then, a bolt 21 is inserted through the elongated hole 24, and the bolt 21 is further inserted into a through hole 25 provided in the swinging member 7, and a nut 22 is screwed to a tip end portion of the bolt 21 to be tightened. Thus, the pulley 5 is supported by the swing arm 13 so as to be rotatable about the center axis of the inner ring member 16.

The auto-tensioner of the present invention configured as described above functions to press the belt 1 by the pulley 5, to cause the pulley 5 to follow the movement of the belt 1, and to suppress the vibration of the belt 1 by the pulley 5. The operation is the same as that of the above-described conventional auto tensioner. Particularly, in the auto-tensioner of the present invention, the inner ring member 16 for pivotally supporting the pulley 5 is supported on the swing member 7 by the bolt 21 inserted into the elongated hole 24. Therefore, when assembling the auto-tensioner to a base such as an engine, the operation of adjusting the tension applied to the belt can be performed easily and reliably.

That is, with the bolt 21 inserted through the elongated hole 24 and the through hole 25 and loosely screwed into the nut 22, the inner ring member 16 supporting the pulley 5 has a length equal to the length of the elongated hole 24. (Strictly speaking, "length-outer diameter of bolt 21"). Therefore, when adjusting the set tension of the belt 1, the pulley 5 is appropriately displaced along the elongated hole 24. When the pulley 5 has reached a desired position (the tension of the belt 1 pushed by the pulley 5 has reached a desired value), the nut 22 is tightened, and the inner ring member 16 is supported and fixed to the swing arm 13. I do. In this case, the distance between the pivot 6 which is the center of swing of the swing member 7 and the center axis of the inner ring member 16 which is the center of rotation of the pulley 5 does not change before and after the adjustment operation. Therefore, the mechanical balance of the auto tensioner does not change, and a desired set tension can be easily and reliably obtained. Further, in the case of the present embodiment, since only the swing member 7 provided with the pulley 5 rotates, the peripheral space of the installation portion does not increase.

In the above embodiment, the swing member 7
A through hole 25 is formed in the bolt 2
1 is screwed into the nut 22 and tightened. However, as shown in FIG.
Screwing a bolt 21 inserted through into the screw hole 26, may be as Ru tightening to <br/>. Further, the elongated hole 24 is formed in the swing arm 13, a through hole is formed in the inner ring member 16, and the nut 2 is inserted into the bolt 21 inserted into the through hole and the elongated hole 24.
2 may be screwed and tightened. In addition, the slot 24
Can be formed on both the inner ring member 16 and the swing arm 13. However, in this case, the bolt 21 is screwed into the nut 22 and tightened. Further, when adjusting the set tension, the inner race member 1 is displaced along the elongated hole 24 without rotating the inner race member 16 around the bolt 21.
6 and the swinging arm 13, and these members 16 and 13 are
The protrusions and recesses may be engaged so that only the relative displacement along 4 is allowed. For example , FIG. 3 showing a structure corresponding to claim 2
As shown in the figure, an arc-shaped convex portion 27 having the same center as the long hole 24 is provided on the inner ring member 16, and an arc-shaped concave portion also having the same center as the long hole 24 is provided on the swing arm 13. 28
Are formed, and the concave portion 28 and the convex portion 27 are engaged with each other.

Next, FIG. 4 shows the present invention.
No. 57, applied to the auto-tensioner,
7 shows a second embodiment of the present invention. This auto-tensioner rotatably supports a base end (lower end in FIG. 4) of a swing member 31 around a fixed shaft 30 which is a first shaft provided on a fixed member 29. An inner ring member 16 having an axis parallel to the fixed axis 30 is fixed to a distal end portion (an upper end portion in FIG. 4) of the member 31 with a bolt 21. Then, the pulley 5 is rotatably supported around the inner ring member 16,
The belt 1 to be tensioned is stretched over the pulley 5. Around the fixed shaft 30, a torsion coil spring 3
Two coil portions 33 are arranged. A pair of locking portions 34a, 34b provided at both ends of the torsion coil spring 32
Are locked to the fixing member 29 and the swinging member 31, respectively, so that the swinging member 31 is provided with elasticity in a direction of pressing the pulley 5 toward the belt 1. still,
The stopper pin 41 provided between the fixing member 29 and the swinging member 31 is pulled out after the belt 1 is stretched over the pulley 5 and is pulled out.
1 enables relative displacement between them.

The fixing arm 35 provided on the fixing member 29
A damper device 37 is provided between the swing member 31 and the swing arm 36 provided on the swing member 31. That is, in the case of the present embodiment, the base end of the cylinder cylinder 38 constituting the damper device 37 is fixed to the tip of the fixed arm 35, and the bottom surface of the receiving block 39 fixed to the tip of the swing arm 36. , The tip of the plunger 40 constituting the damper device 37. The damper device 37 has substantially the same configuration and operation as the above-described damper device 12, and is displaced quickly in the extension direction, but is displaced only slowly in the compression direction. However, since the damper device 37 does not have the function of pressing the pulley 5 against the belt 1, the spring built in the damper device 37 is small. Since such a damper device 37 is not the gist of the present invention, a detailed description is omitted.

Particularly, in the present invention, an arc-shaped long hole 24a centering on the fixed shaft 30 is formed in the center of the inner race member 16 supporting the pulley 5. Then, the inner ring member 16 is supported and fixed to the swing member 31 in a state where the bolt 21 as the coupling and fixing member is inserted through the elongated hole 24a. Therefore, when adjusting the set tension of the auto tensioner, even if the inner ring member 16 supporting the pulley 5 is rotated, the distance between the center of the pulley 5 and the fixed shaft 30 does not change, and the adjustment of the set tension is performed. Can be performed easily and reliably. The operation in this case is the same as in the first embodiment.

Next, FIG. 5 shows the present invention in Japanese Utility Model Application No. 5-29.
5 shows a third embodiment of the present invention applied to the auto-tensioner according to the prior invention described in US Pat. The auto-tensioner of this embodiment is obtained by omitting the fixing member 29 from the structure of the second embodiment. Then, a damper device 37 is supported at the tip of the swing arm 36, and the damper device 37
At the lower end of the arm, projecting from the lower surface of the swing arm 36,
The protrusions (not shown) formed on the base such as the front surface of the cylinder block of the engine can be abutted. Further, the engaging portion 34 b of the torsion coil spring 32 is engaged with the base. The other configuration is a characteristic portion of the present invention, namely, the central portion of the inner race member 16 supporting the pulley 5 or the swing member 3.
1, an inner ring member 16 for supporting a pulley 5 on an oscillating member 31 via a bolt 21 which is a coupling and fixing member, which is provided with an arc-shaped long hole 24b centered on a fixed shaft 30. This is the same as the second embodiment, including the configuration for supporting and fixing the second embodiment. The operation as an auto-tensioner and the operation at the time of adjusting the set tension are the same as those in the second embodiment. However, in the present embodiment, the omission of the fixing member 29 has the same effect of the previous invention that it can be made smaller and lighter than the structure of the second embodiment.

[0028]

Since the auto tensioner of the present invention is constructed and operates as described above, the tension applied to the belt can be easily and reliably adjusted. For this reason, it is possible to eliminate a dimensional error of each component that causes a change in belt tension. Moreover, at this time, the distance between the swing center of the swing member and the center of the pulley does not change, so that the mechanical balance of the auto tensioner does not change, and a desired set tension can be easily and reliably achieved. Is obtained. Further, the swinging during installation part
Since only the material rotates, the space around the installation portion does not increase.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view similar to FIG. 2, showing another example of a support structure for a pulley and a swing arm.

FIG. 4 is a front view showing a second embodiment of the present invention.

FIG. 5 is a front view showing the third embodiment.

FIG. 6 is a front view showing an engine belt drive device provided with an auto tensioner.

FIG. 7 is a sectional view showing a first example of a conventional structure.

FIG. 8 is a sectional view showing the second example.

FIG. 9 is a diagram schematically showing an undesirable state.

[Explanation of symbols]

 Reference Signs List 1 belt 2 drive pulley 3 driven pulley 4 guide pulley or driven pulley 5 pulley 6 pivot 7 swinging member 7a bracket 8 spring 9 cylinder cylinder 10 push rod 11 compression spring 12 damper device 13 swing arm 14 eccentric shaft 15 piston 16 inner ring Member 17, 18 Chamber 19 Oil passage 20 Check valve 21 Bolt 22 Nut 23 Ball 24, 24a, 24b Long hole 25 Through hole 26 Screw hole 27 Convex portion 28 Recess 29 Fixed member 30 Fixed shaft 31 Swing member 32 Twist coil Spring 33 Coil part 34a, 34b Lock part 35 Fixed arm 36 Swinging arm 37 Damper device 38 Cylinder cylinder 39 Receiving block 40 Plunger 41 Stopper pin

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-47552 (JP, A) JP-A-3-355 (JP, U) JP-A-1-148157 (JP, U) JP-J 4- 25555 (JP, Y2) 4-30450 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H ^7/ 00-7/24 F02B 67/06

Claims (2)

(57) [Claims] 1. A first shaft supported by a base, a rocking member whose base end is pivotally supported by the first shaft, and a center axis provided at a distal end of the rocking member. A support member parallel to the first axis, a pulley rotatably supported around the support member around the center axis of the support member, and an elastic force in a direction of pressing the pulley toward the belt. In an auto-tensioner provided with a spring applied to the swing member and a damper device for resisting displacement of the pulley against the elasticity of the spring, the center of the support member and the swing Formed on at least one of the distal end of the member, an arc-shaped elongated hole centered on the first axis, and inserted through the elongated hole, comprising a coupling fixing member parallel to the first axis , The connecting and fixing member allows the supporting member
An auto-tensioner, wherein is fixed to the swing member . 2. An inner ring member, which is a support member, has an arc-shaped convex portion having the same center as the elongated hole, and a swing arm, which is a swing member,
Arc-shaped concave portions having the same center as the elongated holes were respectively formed, and in a state where the concave portions and the convex portions were engaged with each other, a bolt as a coupling and fixing member was formed on the nut or the swing arm. The auto-tensioner according to claim 1, wherein the inner ring member is fixed to the swing arm by being screwed and tightened into a screw hole.