JP2881780B2 - Auto tensioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) An auto-tensioner according to the present invention is used for always applying an appropriate tension to a timing belt of an automobile engine.

(Prior art) In the case of an OHC or DOHC engine, a drive pulley fixed to the end of the crankshaft and a driven pulley fixed to the end of the camshaft to rotate the camshaft in synchronization with the rotation of the crankshaft. It is widely practiced to hang a timing belt between them to synchronize the rotations of the two shafts. Thus, when the timing belt synchronizes the rotation of the crankshaft to which the driving pulley is fixed and the camshaft to which the driven pulley is fixed,
The tension of the timing belt applied between both pulleys
It is necessary to keep it at a predetermined value.

In other words, the timing belt has a slight change in the overall length due to temperature changes, elongation accompanying use, etc., but if this is left as it is, timing belt tooth jumps will occur,
If the phase of the crankshaft is out of phase with the camshaft, the engine cannot exhibit its intended performance.

For this reason, conventionally, an appropriate tension has been applied to various belts such as an engine timing belt by using an auto tensioner as shown in FIGS.

In this conventionally known auto tensioner, a bolt 2 (shown by a solid line only in FIG. 3) is fixed to a fixed mounting base 1 such as an engine block or the like. 1 (shown by a chain line in FIG. 1), the fixed shaft 3 is inserted through the through hole 5 of the oscillating sleeve 4 via the slide bearing 6. The through hole 5 is formed at a position off the center of the oscillating sleeve 4 whose outer peripheral surface is a cylindrical surface. As a result, the outer peripheral surface of the oscillating sleeve 4 is freely displaceable about the fixed shaft 3. is there.

A rolling bearing 7 is provided on the outer peripheral surface of such an oscillating sleeve 4.
The inner ring 8 is externally fitted and fixed. And, between the outer raceways 9, 9 formed on the outer circumferential surface of the inner ring 8 and the inner raceways 11, 11 formed on the inner circumferential surface of the short cylindrical pulley 10,
A plurality of rolling elements 12 are provided, and the pulley 10 is rotatably supported on the outer peripheral surface of the swing sleeve 4.

Further, a bracket 13 is externally fitted and fixed to a portion of the outer peripheral surface of the end portion of the swing sleeve 4 which is separated from the pool 10. Then, a tension spring 16 is provided between the arm piece 14 of the bracket 13 and the pin 15 fixed to the mounting base 1, and the tension spring 16 is pressed against the swing sleeve 4 by pressing the outer peripheral surface of the pulley 10 against the belt 17. Gives elasticity.

In the conventionally known auto tensioner configured as described above, the pulley 10 is pressed against the belt 17 with almost constant elasticity regardless of the change in the total length of the belt 17, and as a result, the pulley 10 Apply a constant tension.

In the illustrated example, a damper mechanism 18 is provided between the inner peripheral surface of the oscillating sleeve 4 and the outer peripheral surface of the fixed shaft 3 so that when the belt 17 vibrates finely, the vibration is attenuated. I have.

(Problems to be Solved by the Invention) However, in the case of the conventional auto tensioner configured and operated as described above, the following inconvenience occurs.

That is, the oscillating sleeve 4 around which the pulley 10 is rotatably supported is provided with an eccentric amount 1 (third
It can move freely in and out of the belt 17 by an amount corresponding to FIG. For this reason, when the eccentricity l is small due to a small diameter of the oscillating sleeve 4 or the like, the pulley 10 is
The distance that can be moved far and near is also small.

As described above, when the distance that the pulley 10 can be moved toward and away from the belt 17 is reduced, it is troublesome to put the belt 17 to be tensioned by the auto tensioner, such as an engine timing belt, on each pulley. Is inevitable.

The auto-tensioner of the present invention solves the above-mentioned disadvantages.

(Means for Solving the Problems) An auto-tensioner according to the present invention includes a rocking plate that rocks around a first pivot provided on a fixed mounting base, and a second plate provided on the rocking plate. A second pivot parallel to the one pivot, and a swing sleeve that swings around the second pivot by inserting the second pivot into a through hole formed at a position off center. A pulley rotatably supported around the swing sleeve, a tip of an arm piece fixed to an end of the swing sleeve, and a pin fixed to a part of the swing plate. The pulley is pressed toward the belt by pulling, a tension spring for applying tension, an arc-shaped long hole formed on the rocking plate and centered on the first pivot, and the long hole is inserted. A screw that is screwed into the screw hole of the mounting base to fix the rocking plate to the mounting base when tightened. Consisting of

(Operation) In the case of the auto-tensioner of the present invention configured as described above, when tension is applied to the belt, a bolt inserted into the long hole of the rocking plate is screwed into a screw hole formed in the mounting base. It is tightened, and a part of the rocking plate is strongly clamped between the head of the bolt and the mounting base. As a result, the rocking plate is connected to the mounting base at the two positions of the first pivot and the bolt tightening portion, and the rocking plate does not rock.

In this state, the pulley is pressed against the belt by swinging about the second pivot provided on the swing plate by the elasticity of the tension applying tension spring, and applies a predetermined tension to the belt.

When the belt is to be bridged, the swing plate is swung about the first pivot while the bolt inserted into the long hole is loosened, and the pulley is moved away from the belt.

The swing plate can swing greatly regardless of the swing amount of the pulley when tension is applied to the belt. For this reason, the pulley is largely retracted from the running position of the belt, and the work of hanging the belt can be easily performed.

After the belt hang-up operation is performed in this manner, the rocking plate is oscillated in a direction opposite to that for performing the hang-up operation using an appropriate jig. ,
The pulley is pressed against the belt while the tension spring is elastically extended. As a result, the pulley is elastically pressed against the belt by the elastic force of the tension spring, and the pulley is urged against the belt irrespective of a delicate change in the entire length due to a temperature change, elongation accompanying use, and the like. Appropriate tension can be continuously applied.

Further, the above-described belt tying operation is performed in a limited space of the engine portion. However, in the case of the auto tensioner of the present invention, a tension spring for applying tension is provided between the tip end portion of the arm piece and the above-mentioned portion. It can be mounted in advance between a pin fixed to a part of the rocking plate. Therefore, it is possible to easily carry out the operation of attaching the belt and the operation of attaching the auto tensioner without the trouble of attaching the spring for applying the tension in a narrow space.

(Embodiment) FIG. 1 shows an embodiment of the present invention. A fixed mounting base 1 such as an engine block is provided with a pivot pin 19 serving as a first pivot. One end of a swing plate 20 is pivotally supported by the pivot pin 19. The swing plate 20 is made by stamping a metal plate or the like, and swings around the pivot pin 19. A fixed shaft 3 serving as a second pivot is fixed to the center of such a swinging plate 20 with bolts 2 in the same manner as in the case of the above-described conventional auto tensioner. That is,
Although not shown, a screw hole is formed in the center portion of the swinging plate 20, and the bolt 2 inserted through the through hole 25 of the fixed shaft 3 is screwed into the screw hole, and further tightened to fix the fixed shaft. 3 is fixed to the center of the rocking plate 20. In this state, the fixed shaft 3
The pivot pin 19 is parallel.

A rocking sleeve 4 is provided around the fixed shaft 3 via a slide bearing 6 as in the case of the above-described conventional auto tensioner. Further, a cylindrical pulley 10 is rotatably supported on the outer peripheral surface of the oscillating sleeve 4 via a rolling bearing 7 (see FIG. 3).

Further, a bracket 13 is externally fitted and fixed to a portion of the outer peripheral surface of the swing sleeve 4 which is separated from the pulley 10 (see FIG. 3 for details). Further, a tension spring 16 for applying tension is provided between the arm piece 14 of the bracket 13 and the pin 21 fixed to the end of the swing plate 20. The tension spring 16 gives the oscillating sleeve 4 an elastic force in a direction of pressing the outer peripheral surface of the pulley 10 against the belt 17.

Further, a part of the rocking plate 20 is formed with an arc-shaped long hole 22 centered on a pivot pin 19 that pivotally supports one end of the rocking plate 20, and the long hole 22 is inserted therethrough. The bolt 23 is screwed into a screw hole formed in the mounting base 1.

In the case of the auto-tensioner of the present invention configured as described above, when applying tension to the belt 17 with which the outer peripheral surface of the pulley 10 is in contact, the bolt 23 inserted through the long hole 22 of the rocking plate 20,
It is screwed and tightened into a screw hole formed in the mounting base 1. And
A part of the rocking plate 20, that is, both side edges of the long hole 22 is strongly clamped between the head of the bolt 23 and the mounting base 1. As a result, the rocking plate 20 is coupled to the mounting base 1 at two points, that is, the pivot pin 19 serving as the first pivot and the tightening portion of the bolt 23, and the rocking plate 20 rocks. Things disappear.

In this state, the fixed shaft 3 provided on the rocking plate 20 is the same as when the fixed shaft 3 is directly fixed to the mounting base 1.
The pulley 10 rotatably supported on the outer peripheral surface of the oscillating sleeve 4 pivotally supported on the fixed shaft 3 owes to the elasticity of the tension spring 16 as shown in FIG. The belt 17 is swung clockwise and pressed against the belt 17 to apply a predetermined tension to the belt 17.

Also, when performing the above-mentioned belt 17 bridging work,
Loosen the bolt 23 inserted into the long hole 22 of the rocking plate 20. Then, the swing plate 20 is swung counterclockwise in FIG. 1 around the pivot pin 19 to move the pulley 10 away from the belt 17.

When the pulley 10 is moved away from the belt 17 in this manner, the swing plate 20 swings largely regardless of the swing amount (proportional to the eccentricity l) of the pulley 10 when tension is applied to the belt 17. It is possible to do. Therefore, the pulley 10 is largely retracted leftward from the running position of the belt 17 in FIG.

(Effects of the Invention) Since the auto tensioner of the present invention is configured and operates as described above, it is possible to easily carry out the operation of passing the belt to be tensioned over each pulley while keeping the function of the conventional auto tensioner. You will be able to do it.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is a front view showing an example of a conventional auto tensioner, and FIG. 3 is a sectional view taken along line AA of FIG. 1: Mounting base, 2: Bolt, 3: Fixed shaft, 4: Swing sleeve, 5:
Through hole, 6: sliding bearing, 7: rolling bearing, 8: inner ring, 9: outer race, 10: pulley, 11: inner race, 12: rolling element, 13: bracket, 14: arm, 15: pin , 16: tension spring, 17: belt,
18: damper mechanism, 19: pivot pin, 20: rocking plate, 21: pin, 2
2: long hole, 23: bolt, 24: tension spring, 25: through hole.

Claims (1)

(57) [Claims] 1. A swing plate provided on a fixed mounting base for swinging about a first pivot, a second pivot provided on the swing plate and parallel to the first pivot. By inserting the second pivot into a through hole formed at a position off the center, a swing sleeve that swings about the second pivot and a rotatable support around the swing sleeve are provided. Tension between the set pulley, the tip of the arm piece fixed to the end of the swing sleeve, and the pin fixed to a part of the swing plate, and presses the pulley toward the belt. A tension spring for application, an arc-shaped long hole formed on the rocking plate, centered on the first pivot, is inserted through the long hole, and screwed into a screw hole of the mounting base. An auto-tensioner comprising a bolt for fixing the rocking plate to the mounting base when tightened.