JP4236718B2 - Pulley device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulley device that is engaged with a timing belt of an automobile engine.
[0002]
[Prior art]
For example, in an automobile engine, in order to reduce the weight and noise, the camshaft is often driven to rotate using a timing belt. This type of timing belt is stretched between the crankshaft pulley and the camshaft pulley, and by transmitting the rotation of the crankshaft to the camshaft, the camshaft rotates in a time relationship associated with the engine cycle. It has a role to make. In such a belt transmission device, the pulley device and the auto tensioner are arranged to prevent the timing belt from loosening and to apply a predetermined tension.
[0003]
As a pulley device of this type, for example, a pulley device shown in FIG. 3 is known. The pulley swing shaft 12 is swingably supported by a fulcrum shaft 14 at a position eccentric with respect to the pulley rotation axis O1, and after setting the initial tension of a belt (not shown), the engine is connected via the fulcrum shaft 14. It is fixed to the main body (not shown). The fulcrum shaft 14 has a fixed axis O3 at a position eccentric to the axis O2, and is fixed to the engine body by a bolt (not shown) disposed on the fixed axis O3. Reference numeral 16 denotes a washer 16 integrated with the swing shaft 12.
[0004]
An arm 15 is fixed to the swing shaft 12, and the rod 20a of the auto tensioner 20 abuts on the arm 15 so that the pulley is swing-biased with a predetermined force toward the belt tension side. As a result, a predetermined tension is applied to the belt, and at the same time, vibrations of the belt are absorbed by the damper action of the auto tensioner 20.
[0005]
The initial tension of the belt is set as follows. First, the fulcrum shaft 14 is temporarily fixed to the engine body with a bolt, and a belt is hung on the outer peripheral surface of the pulley body 11. Next, the fulcrum shaft 14 is rotated and adjusted with respect to the swing shaft 12, and the pulley is swung to a desired position (position where the belt tension becomes a desired value) in combination with the urging force of the auto tensioner 20. Let Thereafter, the bolt is fully tightened to fix the fulcrum shaft 14 at that position.
[0006]
This type of pulley device can absorb the initial belt length and position errors of the crankshaft pulley, camshaft pulley, etc. by changing the fixing position of the fulcrum shaft 14 and can be fixed to the axis O2 of the fulcrum shaft 14. Compared with the configuration in which the shaft center O3 is concentric, the amount of swinging displacement of the pulley can be increased, so that there is an advantage that the belt tension setting range is wide.
[0007]
[Problems to be solved by the invention]
In this type of pulley device, as shown in FIGS. 3A and 3B, there are two positions of the fulcrum shaft 14 having the same belt tension at intervals of 180 degrees. Among them, at the position shown in FIG. 3B (the fixed axis O3 is on the side far from the rotation center O1), the arm 15 is biased against the rod 20a of the auto tensioner 20 (the contact surface of the arm 15 and the The angle between the tensioner 20 and the axis of the rod 20a makes contact with each other at an angle relatively smaller than 90 °.) As a result , the durability of the auto tensioner 20 is reduced. The position must be set to the position shown in 3 (a) (the fixed axis O3 is on the side closer to the rotation center O1). 3A, the arm 15 correctly contacts the rod 20a of the auto tensioner 20. {Compared with the state shown in FIG. 3B, the contact surface of the arm 15 and the rod 20a of the auto tensioner 20 The angle formed with the axis is 90 ° or close thereto . }.
[0008]
In the conventional pulley apparatus, the fulcrum shaft 14 can take the two positions shown in FIGS. 3A and 3B with respect to the same belt tension. Therefore, in addition to checking the belt tension when setting the initial tension, the fulcrum shaft 14 is shown in FIG. It is necessary to check whether the position is correct as shown in (a), and the tension setting work is complicated.
[0009]
An object of the present invention is to simplify the tension setting work in this type of pulley apparatus.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, a pulley body engaged with a belt, a swing shaft provided on an inner side of the pulley body and provided with an arm with which a rod of an auto tensioner abuts, and a pulley body are swung. A pulley provided with a rolling bearing that is rotatably supported with respect to the dynamic shaft, and a swing shaft that is swingably supported at a position that is eccentric with respect to the rotational axis (O1) of the swing shaft; and The fulcrum shaft is mainly fixed to the fulcrum shaft having the fixed axis (O3) at a position eccentric with respect to the axis (O2) , and the fulcrum shaft is fixed by adjusting the positional relationship of the fulcrum shaft with respect to the swing axis. The belt is fixed to the fixed member by the shaft center (O3) , the rod of the auto tensioner is brought into contact with the arm of the swing shaft, and the pulley is urged to the tension side of the belt by the auto tensioner. In pulley device that applies tension Has a regulating means for regulating the rotation angle with respect to the swing axis of the fulcrum shaft in a predetermined range (theta), the range of the rotational angle (theta) is fixed axis of the pivot shaft (O3) is the axis (O2) 180 degrees in the left and right rotation directions from the center of the angle that is closer to the rotation axis (O1) of the rocking shaft and is a half of the rotation angle range (θ) . The configuration was less than °. This restricting means may be an engaging means formed between a washer integrally formed with the fulcrum shaft or fixed integrally with the fulcrum shaft, and the swing shaft.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a pulley device engaged with a timing belt of an automobile will be described.
[0012]
The pulley apparatus shown in FIG. 1 includes a pulley body 1 made of, for example, a steel plate press that is engaged with a timing belt (not shown) of an automobile, a swing shaft 2 disposed inside the pulley body 1, and a pulley body 1. A pulley having a rolling bearing, for example, a double-row angular ball bearing 3 interposed between the inner peripheral surface 1a and the outer peripheral surface 2a of the swing shaft 2, and the swing shaft 2 are eccentric with respect to the rotational axis O1 of the pulley. The fulcrum shaft 4 is supported mainly so as to be swingable at the position and has a fixed axis O3 at a position eccentric to the axis O2.
[0013]
The oscillating shaft 2 has a through hole 2b at a position deviated by a predetermined amount from its axial center O1 (same as the rotational axis of the pulley), and the fulcrum shaft 4 is inserted into the through hole 2b via, for example, a sliding bearing. It is. Further, an arm 5 is fixed to the swing shaft 2 (for example, fixed to the left end face of the swing shaft 2 with a bolt), and an auto tensioner rod (not shown) is applied to the arm 5. By contacting, the pulley is oscillated and biased with a predetermined force toward the tension side of the belt.
[0014]
The fulcrum shaft 4 is held in the through hole 2b of the swing shaft 2 by a washer 6 and a washer 7 integrated at both shaft ends. For example, the head of a bolt (not shown) is seated on the washer 6, and the washer 7 is applied to an engine body (not shown) as a fixed side member. One of the washer 6 and the washer 7 can be formed integrally with the fulcrum shaft 4. Alternatively, both the washer 6 and the washer 7 may be integrally fixed to the fulcrum shaft 4. Further, the fulcrum shaft 4 has a through hole 4a at a position eccentric from the axis O2 by a predetermined amount, and is fixed to the engine body via a washer 7 by a bolt (not shown) attached to the through hole 4a. The Therefore, the fixed axis O3 of the fulcrum shaft 4 coincides with the axis of the bolt.
[0015]
In this embodiment, the washer 6 has a claw portion 6a protruding on the opposite side (a side far from the rotation axis O1) from the fixed axis O3 across the axis O2 of the fulcrum shaft 4, and the tip of the claw portion 6a. And a bent portion 6b bent on the outer peripheral surface 2a side of the swing shaft 2. Therefore, when the fulcrum shaft 4 is rotated at an angle with respect to the swing shaft 2, the bent portion 6b of the washer 6 engages with the outer peripheral surface 2a of the swing shaft 2 as shown by a dotted line in FIG. Thus, the fulcrum shaft 4 can no longer rotate in that direction. There is one engagement position between the bent portion 6b of the washer 6 and the outer peripheral surface 2a of the swing shaft 2 with respect to the rotation of the fulcrum shaft 4 in both the left and right directions. The rotation angle with respect to is restricted to the range of the angle θ between the left and right engagement positions. The angle θ is an angle of less than 360 degrees (θ / 2 <180 °).
[0016]
When setting the initial tension of the belt, first, the fulcrum shaft 4 is temporarily fixed to the engine body with a bolt, the belt is hung on the outer peripheral surface of the pulley body 1, and then the fulcrum shaft 4 is attached to the swing shaft 2. By adjusting the rotation, the pulley is oscillated and displaced to a desired position (position where the belt tension becomes a desired value) in combination with the urging force of the auto tensioner. Thereafter, the bolt is fully tightened to fix the fulcrum shaft 4 at that position. As described above, in this type of pulley apparatus, there are two positions of the fulcrum shaft 4 having the same belt tension at intervals of 180 degrees {FIGS. 3 (a) (b)}. 4 is controlled within the range of the above-mentioned angle θ (θ / 2 <180 °), the position of the fulcrum shaft 4 at which the desired belt tension is obtained is a normal one {FIG. Only the position shown in (a)}. Therefore, when setting the initial tension, the work of confirming the position of the fulcrum shaft 4 becomes unnecessary, and the tension setting work is simplified. Further, since there is no fear that the fulcrum shaft 4 is fixed at the wrong position {position shown in FIG. 3B}, the reliability of the product is improved.
[0017]
As described above, the positional relationship in the rotational direction of the fulcrum shaft 4 with respect to the swing shaft 2 is adjusted, and the fulcrum shaft 4 is fixed to the engine body by the fixed axis O3, and the pulley is attached to the belt tension side by the auto tensioner. By swinging and energizing the belt, a predetermined tension is applied to the belt, and at the same time, the vibration of the belt is absorbed by the damper action of the auto tensioner.
[0018]
In the embodiment shown in FIG. 2, the restricting means is constituted by a claw portion 6 a of the washer 6 and a pair of convex portions 2 c provided on the end surface of the swing shaft 2. Therefore, the washer 6 in this embodiment does not include the bent portion 6b shown in FIG. By engaging the claw portion 6a and the convex portion 2c in the rotation direction, the rotation angle of the fulcrum shaft 4 with respect to the swing shaft 2 is restricted within the range of the angle θ (θ / 2 <180 °).
[0019]
In the embodiment described above, a restricting means for restricting the rotation angle of the fulcrum shaft 4 to a predetermined range (angle θ) is provided between the washer 6 and the swing shaft 2. As long as the effect is achieved, the restricting means may be provided at another location. For example, the restricting means can be configured as an engaging means formed between the washer 6 and the swing shaft 2. Further, the outer raceway surface of the rolling bearing 3 can be directly formed on the inner peripheral surface 1 a of the pulley body 1, and the inner raceway surface of the rolling bearing 3 can be directly formed on the outer peripheral surface 2 a of the swing shaft 2. Furthermore, the material of the pulley body 1, the form, the form of the arm 5, the bearing form of the rolling bearing 3, etc. are not limited to those exemplified.
[0020]
【The invention's effect】
According to the present invention, the rotation angle (θ) of the fulcrum shaft with respect to the oscillating shaft is set so that the fixed axis (O3) of the fulcrum shaft is closer to the rotational axis (O1) of the oscillating shaft than the axis (O2). Restricting means for restricting the rotation angle to less than 180 ° (θ / 2 <180 °) in the left rotation direction and the right rotation direction from the center of the angle that is located at a position that is 1/2 of the rotation angle range (θ). Therefore, the position of the fulcrum shaft that achieves the desired belt tension is only one normal position, and the work of confirming the fixed position of the fulcrum shaft is not required when setting the belt tension. Therefore, the belt tension setting operation is simplified as compared with the prior art. Moreover, since there is no fear that the fulcrum shaft is fixed at an incorrect position, the reliability of the product is improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view (FIG. A) and a side view (FIG. B) showing an embodiment.
FIG. 2 is a partial cross-sectional view (FIG. A) and a side view (FIG. B) showing another embodiment.
FIG. 3 is a side view showing a conventional pulley apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pulley body 2 Oscillating shaft 2c Convex part 3 Rolling bearing 4 Support shaft 6 Washer 6a Claw part 6b Bending part

Claims (2)

A pulley body that is engaged with the belt, a swing shaft that is disposed inside the pulley body and that has an arm that contacts the rod of the auto tensioner, and a roller that rotatably supports the pulley body with respect to the swing shaft A pulley with a bearing;
The swing shaft is supported swingably at a position eccentric to the rotation axis (O1) of the swing shaft, and the fixed axis (O3) is positioned eccentric to the shaft center (O2) . With a fulcrum shaft having
The position of the fulcrum shaft in the rotational direction relative to the rocking shaft is adjusted so that the fulcrum shaft is fixed to the fixed member by the fixed axis (O3) and the rod of the auto tensioner is brought into contact with the arm of the rocking shaft. In the pulley device for applying a predetermined tension to the belt by urging the pulley toward the tension side of the belt with an auto tensioner,
There is a restricting means for restricting the rotation angle of the fulcrum shaft with respect to the swinging shaft to a predetermined range (θ). The rotation angle range (θ) is such that the fixed axis (O3) of the fulcrum shaft is in the axis (O2). 180 ° in the left rotation direction and the right rotation direction from the center of the angle which is on the side closer to the rotation axis (O1) of the swing shaft and is a half of the range (θ) of the rotation angle . Pulley device characterized by being less than.   2. The pulley apparatus according to claim 1, wherein the restricting means is an engaging means formed between a washer integrated with a fulcrum shaft and a swing shaft.

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