JPH09144822A - Belt tensile force adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a shaft from biting into a bracket when a pulley moves by forming an inclined face inclining so that a thickness of a plane part becomes small as it proceeds in the opposite direction of the tensile force direction of a belt, on one end side surface of the plane part of the bracket. SOLUTION: An inclined face 3e where a thickness of a bracket 3 microscopically inclines (an inclination θ: about 0.5 deg.) as it proceeds in the opposite direction of tensile force T of a belt 2, is formed on the adjusting bolt 4 side of a planar part (a side surface part) 3c of the bracket 3. When a fastening means 8 is released, the moment by the tensile force T of the belt 2 is applied to a shaft 5, and since an adjusting bolt 4 is loosely fitted to a through hole 3b of the bracket 3, the shaft 5 microscopically inclines in the direction that one end 51 of the shaft 5 moves in the opposite direction of the tensile force T and the other end 52 moves in the tensile force T direction. Therefore, an outer peripheral part 5e of the shaft 5 is prevented from biting into the plane part 3e of the bracket 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tension adjusting device for adjusting belt tension in belt transmission.

[0002]

2. Description of the Related Art Conventionally, a belt tension adjusting device is provided in a belt transmission mechanism for transmitting the rotational power of an engine to an electromagnetic clutch for a compressor of a vehicle refrigeration cycle via a crank pulley. A conventional belt tension adjusting device will be described below with reference to FIG.

In this belt tension adjusting device 1, an adjusting bolt 4 is loosely fitted to an upper surface portion 3a of a bracket 3, and one end 51 of a shaft 5 is movably connected to the adjusting bolt 4 by a screw. A pulley 6 supporting the belt 2 is rotatably held at the end 52, and the tension of the belt 2 is adjusted by moving the shaft 5 along the side surface portion 3c by the rotation of the adjusting bolt 4. It is a thing.

Here, the screw is the screw connecting portion 5a.
Of the adjusting bolt 4 and the thread 4c of the adjusting bolt 4. A cylindrical collar 7a is fitted on the outer peripheral portion of the shaft portion 5c of the shaft 5 so that the pulley 6 and the side surface portion 3c of the bracket 3 do not come into contact with each other. Then, due to the fastening force of the nut 8, the collar-shaped portion 5d adjacent to the entire surface of the collar 7a and the screw coupling portion 5a.
The entire surface is crimped to the side surface 3c of the bracket 3, and the pulley 6
Is assembled in the state shown in FIG. When adjusting the tension of the belt 2, the fastening force of the nut 8 is released and the collar 7
a All over the entire surface and the collar-shaped portion 5d, the side surface portion 3 of the bracket 3
The shaft 5 is moved in the vertical direction in FIG. 3 while being in contact with c.

[0005]

However, when the fastening force of the nut 8 is released, a moment due to the tension T of the belt 2 is applied to the shaft 5, and the adjusting bolt 4 is also applied.
Since the shaft 5 is loosely fitted in the through hole 3b, the shaft 5 is slightly inclined in a direction in which one end 51 of the shaft 5 moves upward in FIG. 3 and the other end 52 moves downward in FIG. Then, the collar-shaped portion 5d
3 of FIG. 3 and the lower part 7 of FIG. 3 of the collar 7a.
c is strongly bitten into the side surface portion 3c of the bracket 3. Here, the force applied from the upper portion 5e and the lower portion 7c to the side surface portion 3c of the bracket 3 is indicated by arrows A and B.

When the pulley 6 is moved upward in FIG. 3, with respect to the upper portion 5e of the collar-shaped portion 5d, the displacement direction C of the upper portion 5e and the direction of the biting force indicated by an arrow A in FIG. And the tension T increases as it is moved upward, so that the above-mentioned bite progresses, and finally, the flange-shaped portion 5d with respect to the side surface portion 3c of the bracket 3.
Will not be able to move.

In the lower portion 7c of the collar 7a, the displacement direction C of the lower portion 7c is opposite to the direction of the indenting force indicated by the arrow B in FIG. 3, so that the indentation does not proceed. When moving the pulley 6 downward in FIG. 3,
Since the tension T decreases as it is moved, the above biting does not proceed. Then, conventionally, in order to prevent the above-mentioned bite, the side surface portion 3c of the bracket 3 made of metal is polished to improve the surface accuracy of the side surface portion 3c of the bracket 3. By doing so, the collar-shaped portion 5 of the shaft 5
The d is smoothly moved along the side surface portion 3c of the bracket 3 to prevent the above-mentioned problem of being bitten. However, even if the surface accuracy is increased, the above-mentioned bite cannot be reliably prevented, and since the above polishing step is required, the manufacturing process of the bracket 3 becomes complicated and the manufacturing cost of the bracket 3 becomes high.

[0008] The present invention has been made in view of the above points,
The purpose of the present invention is to prevent the shaft from biting into the bracket when the pulley is moved, without polishing the bracket.

[0009]

In order to achieve the above object, the present invention employs the following technical means. In the invention according to claim 1, the through hole (3
An adjusting bolt (4) is loosely fitted in b), and an abutting portion (5d) that abuts and moves on the flat surface portion (3c) of the bracket (3) is attached to one end (51) of the shaft (5). Fastening means (8) for adhering the contact portion (5d) to the flat portion (3c) is provided at the tip of the other end (52) of the shaft (5) provided adjacent to each other.

Then, after releasing the fastening force of the fastening means (8), the adjusting bolt (4) is rotated and the shaft (5) is moved along the plane portion (3c), so that the belt (2) is moved. In the belt tension adjusting device for adjusting the tension (T), the flat surface portion (3c) has a flat surface portion on a surface on the side of the one end (51) as it goes in a direction opposite to the tension (T) direction of the belt (2). It is characterized in that an inclined surface (3e) is formed so as to reduce the thickness of (3c).

In this technical means, fastening means (8)
When the fastening force is released, the moment due to the tension (T) is applied to the shaft (5), and moreover, the adjustment bolt (4) is loosely fitted in the through hole (3b), so that one end (51) of the shaft (5) is ) Moves in the direction opposite to the tension (T) direction, and the other end (52) moves in the tension (T) direction,
The shaft (5) tilts slightly.

As a result, the contact portion (5d) has a flat surface (3) in the direction opposite to the tension (T) direction.
Although it slightly inclines so as to approach c), the inclined surface (3
Since e) is also formed to incline in the same direction as the minute inclination of the contact portion (5d), the contact portion (5d) of the shaft (5) is different from the tension (T) direction. The outer peripheral portion (5e) on the opposite direction side is prevented from being strongly bitten into the flat surface portion (3c).

Therefore, when the contact portion (5d) is moved in the direction opposite to the tension (T) direction, the above-mentioned indentation is prevented from progressing, and the contact portion with respect to the flat surface portion (3c) is prevented. The problem that (5d) cannot be moved can be prevented. In the invention according to claim 2, the inclined surface (3e) is inclined substantially parallel to the minute inclination of the contact portion (5d) when the fastening by the fastening means (8) is released. It is characterized by being. Therefore, since the above-mentioned indentation hardly occurs, the problem that the contact portion (5d) cannot be moved can be more effectively prevented.

Further, in the invention according to claim 3,
The bracket (3) is characterized by being formed by die casting. By doing this, the bracket (3)
The surface of the flat portion (3c) is relatively smooth, and the contact portion (5d) can smoothly move on the surface of the smooth flat portion (3c), so that the above-mentioned biting can be prevented more effectively.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a belt tension adjusting device of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the belt tension adjusting device 1 according to the present invention includes an engine 100.
Is provided in a belt transmission mechanism that transmits the rotational power of the above to the compressor electromagnetic clutch 300 of the vehicle refrigeration cycle via the crank pulley 200. This is for supporting the inner peripheral surface side of the belt 2 by a pulley 6, and the pulley 6 is mounted on the engine block 1 via a bracket 3.
01 is fixed.

Then, as shown in FIG. 1, the bracket 3
By moving the shaft 5 in the up-down direction in FIG. 1 along the adjusting bolt 4 provided substantially parallel to the side surface portion 3c of the pulley 6, the pulley 6 provided on the shaft 5 is moved.
It adjusts the tension of the belt 2 which is suspended. In FIG. 1, the belt 2 is supported above the pulley 6, and the tension T of the belt 2 is applied to the pulley 6.

The components and assembly structure of the belt tension adjusting device of the present invention will be specifically described below. In FIG. 1, the bracket 3 is made of an aluminum alloy and is die-cast to have a U-shaped cross section. On the side of the adjustment bolt 4 of the side surface portion (flat surface portion) 3c of the bracket 3, there is formed an inclined surface 3e that is inclined so that the thickness of the side surface portion 3c of the bracket 3 becomes smaller toward the direction opposite to the tension T. Has been done. In this embodiment, the inclination angle θ of the inclined surface 3e is 0.5 °.
It is a very small angle. Here, in FIG. 1, the inclined surface 3e
In order to make it easy to understand, the inclination angle θ is shown larger than the actual one.

A circular through hole 3b is formed in the upper surface portion (protruding portion) 3a of the bracket 3 so as to penetrate substantially parallel to the side surface portion 3c of the bracket 3, and the through hole 3b is formed in the through hole 3b. The adjustment bolt 4 is rotatably loosely fitted. By doing this, the adjustment bolt 4
Are arranged substantially parallel to the side surface portion 3c of the bracket 3. The adjusting bolt 4 is made of an iron-based alloy having excellent tensile strength, and the diameter of the shaft portion 4c of the adjusting bolt 4 is slightly smaller than that of the through hole 3b (about 1 m).
The diameter of the head portion 4b of the adjusting bolt 4 is larger than the diameter of the through hole 3b.

A shaft 5 is arranged substantially perpendicular to the adjusting bolt 4 and is movably connected to the adjusting bolt 4 via a screw connecting portion 5a at one end 51 of the shaft 5. Specifically, the screw coupling portion 5a
Screw hole 5b (screw) formed on the and adjustment bolt 4
And the screw thread 4c (screw) formed on the screw are engaged with each other, and by rotating the head 4b of the adjusting bolt 4, the screw coupling portion 5a moves along the screw thread 4c of the adjusting bolt 4. It is like this.

Here, the screw thread 4c is formed in the shaft portion 4a of the adjusting bolt 4 at a lower portion in FIG. 1 than a portion corresponding to the through hole 3b of the bracket 3. Further, a collar-shaped portion (contact portion) 5d is integrally formed on the side surface portion 3c side of the bracket 3 in the screw coupling portion 5a. The shaft 5 is made of an iron-based alloy having excellent tensile strength.

Then, on the side surface portion 3c of the bracket 3,
A long hole-shaped guide hole 3d is formed, and this guide hole 3d
The shaft portion 5c of the shaft 5 penetrates the shaft 5 substantially vertically. The shaft portion 5c of the shaft 5 moves in the vertical direction in FIG. 1 along the guide hole 3d. Further, the pulley 6 is rotatably attached to the shaft portion 5c of the shaft 5 on the other end 52 side through the bearing 9, and the shaft portion 5 of the shaft 5 is rotatable.
It is provided substantially perpendicular to c.

In the shaft portion 5c of the shaft 5, a cylindrical collar 7a is fitted to the right side of the bearing 9 in FIG. 1, and a ring-shaped shim 7 is fitted to the left side of the bearing 9 in FIG.
d and 7e are fitted together. Then, the nut 8 is fastened to a screw thread (not shown) at the tip of the other end 51 side of the shaft 5 with a predetermined fastening force, whereby the collar-shaped portion 5 of the screw coupling portion 5a is tightened.
d is crimped to the side surface portion 3c of the bracket 3, and the collar 7a, the bearing 9, and the shims 7d and 7e are pressed to the flat surface portion 3c side, so that the collar 7a is attached to the side surface portion 3c of the bracket 3.
It is crimped to.

By doing so, the shaft 5 can be fixed to the side surface portion 3c of the bracket 3 and the pulley 6 can be positioned at a predetermined position of the shaft portion 5c of the shaft 5. The collar 7a allows the pulley 6 to rotate without contacting the side surface portion 3c of the bracket 3. In addition, the adjustment bolt 4 and the shaft 5
Since the tensile strength is excellent, the adjusting bolt 4 and the shaft 5 are treated as being almost inflexible.

The method of assembling the pulley 6 to the bracket 3 will be described below. First, the screw coupling portion 5a of the shaft 5
1, the shaft 5 is passed through the guide hole 3b of the bracket 3 so as to be located on the right side of the side surface portion 3c of the bracket 3 in FIG. Then, the adjusting bolt 4 is inserted into the through hole 3b of the bracket 3, and the screw hole 5b of the screw coupling portion 5a of the shaft 5 and the screw thread 4c of the adjusting bolt 4 are meshed with each other and screwed. Then, on the shaft portion 5c of the shaft 5, the pulley 6, the shims 7d, 7 provided with the collar 7, and the bearing 9 are provided.
Then, the belt 2 (see FIG. 2) is hung on the pulley 6 after fitting e and loosely attaching the nut 8 to the thread. Then, the head 4a of the adjusting bolt 4 is rotated to move the position of the pulley 6, and the collar 7 is tightened by the nut 8 at a position where the belt 2 (see FIG. 2) has a predetermined tension T.
a and the collar-shaped portion 5d of the screw coupling portion 5a are crimped to the side surface portion 3c of the bracket 3. By doing so, the moment due to the tension T is received by the side surface portion 3c of the bracket 3, the collar 7a and the screw coupling portion 5a are fixed to the bracket 4, and the pulley 6 can be fixed at a predetermined position.

Here, if the inclination angle θ of the inclined surface 3e is made extremely large, when the nut 8 is tightened, the entire surface of the collar 7a is crimped to the side surface 3a of the bracket 3, and the collar portion 5d is also greatly inclined. Since an attempt is made to crimp along the inclined surface 3e, the shaft portion 5 near the collar-shaped portion 5d of the shaft 5
Unreasonable force is applied to c in the upward direction in FIG. On the other hand, in the present embodiment, since the inclination angle θ is as small as about 0.5 °, when tightened with the nut 8,
The entire surface of the collar-shaped portion 5d can be crimped without applying the excessive force.

When adjusting the tension of the belt 2 again, the position of the idle pulley 1 relative to the bracket 3 is changed by releasing the fastening force of the nut 8 and then turning the head portion 4b of the adjusting bolt 4. The pulley 6 is fixed to the bracket 3 by moving it in the vertical direction in FIG. 1) for positioning, and then tightening the nut 8 with a predetermined fastening force.

When the fastening force of the nut 8 is released,
The collar 7a and the collar-shaped portion 5d are loosely crimped to the side surface portion 3c, a moment due to the tension T is applied to the shaft 5, and the adjust bolt 4 is loosely fitted in the through hole 3b. The shaft 5 slightly tilts in the direction in which 51 moves upward in FIG. 1 and the other end 52 moves downward in FIG. Here, the shaft 5 maintains a slightly inclined state by the lower portion 7c of the collar 7a in FIG. 1 being locked to the bracket 3.

The collar-shaped portion 5d of the shaft 5 is shown in FIG.
Although it slightly inclines toward the side surface portion 3c as it goes upward in the middle, the inclined surface 3e is also formed so as to incline substantially parallel to the minute inclination of the collar-shaped portion 5d. The upper portion 5e of the collar-shaped portion 5d of FIG. 5 in FIG. 1 is prevented from being strongly bitten by the side surface portion 3c. By the way,
The inclination angle θ of the inclined surface 3e is set in advance so that the inclined surface 3e is substantially parallel to the minute inclination of the collar-shaped portion 5d when the fastening force of the nut 8 is released. The inclination angle θ is set according to the dimensions of the bracket 3, the shaft 5, the collar 7a, etc., the degree of release of the fastening force, and the magnitude of the tension T.

Therefore, when the collar-shaped portion 5d is moved upward in FIG. 1, the above-mentioned biting does not proceed, and the problem that the collar-shaped portion 5d cannot move with respect to the side surface portion 3c can be solved. . In this way, the belt tension adjusting device 1 that prevents the above-mentioned biting can be obtained by forming the bracket 3 having the inclined surface 3e by die casting without cutting the side surface portion 3c of the bracket 3. Therefore, the manufacturing method of the belt tension adjusting device 1 becomes easy, and the belt tension adjusting device 1 can be manufactured at low cost.

Further, in this embodiment, since the bracket 3 is formed by die casting, the surface of the bracket 3 is in a comparatively smooth state. Therefore, the collar-shaped portion 5d of the screw coupling portion 5a is not
Since it is possible to move smoothly along the surface of c, it is possible to prevent the above-mentioned bite more effectively. In the above embodiment, the inclination angle θ of the inclined surface 3e is set to about 0.5 °, but the present invention is not limited to this. However, the inclination angle θ of the inclined surface 3e may be set so as to follow the minute inclination of the collar-shaped portion 5d when the fastening force of the nut 8 is released.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a belt tension adjusting device of this embodiment.

FIG. 2 is a diagram showing an assembly place of the belt tension adjusting device of the present embodiment.

FIG. 3 is a side view of a conventional belt tension adjusting device.

[Explanation of symbols]

2 ... Belt, 3 ... Bracket, 3a ... Upper surface part (projection part), 3b ... Through hole, 3c ... Side surface part (flat surface part), 3d ...
Guide holes, 3e ... Inclined surface, 4 ... Adjust bolt, 4c ...
Screw thread (screw), 5 ... Shaft, 5b ... Screw hole (screw), 5d ... Collar portion (contact portion), 6 ... Pulley, 8 ... Nut (fastening means), T ... Tension.

Front Page Continuation (72) Inventor Toshihiko Kanehara 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (3)

[Claims] 1. A bracket (3) is provided with a flat surface portion (3c) in which a long hole-shaped guide hole (3d) is formed, and the bracket (3) is provided with a protrusion portion (3c) extending from the flat surface portion (3c). 3a) is formed, and a through hole (3b) is formed in the protruding portion (3a) so as to penetrate substantially parallel to the long hole direction of the guide hole (3d) of the flat surface portion (3c). An adjusting bolt (4) is loosely fitted in the through hole (3b), and the guide hole (3d) is provided in the adjusting bolt (4).
One end (51) of the shaft (5) penetrating substantially perpendicularly is movably coupled by a screw (4c, 5b), and an abutting portion (5d) abutting and moving on the flat surface portion (3c) is formed. A pulley (6) that is provided adjacent to the one end (51) of the shaft (5) and that supports the belt (2) on the other end (52) side of the shaft (5) is rotatable. The other end (52) side of the shaft (5) is provided with a fastening means (8) for crimping the abutting portion (5d) to the flat surface portion (3c). After the fastening is released, the tension (T) of the belt (2) is adjusted by rotating the adjusting bolt (4) and moving the shaft (5) along the flat surface portion (3c). In the belt tension adjusting device, the flat surface (3c) On the surface on the side of the one end (51), the thickness of the plane portion (3c) becomes smaller in the direction opposite to the tension (T) direction of the belt (2) acting on the pulley (6). A belt tension adjusting device characterized in that an inclined surface (3e) is formed. 2. The contact surface (5) of the inclined surface (3e) when the fastening by the fastening means (8) is released.
The belt tension adjusting device according to claim 1, wherein the belt tension adjusting device is inclined substantially parallel to the minute inclination of d). 3. The belt tension adjusting device according to claim 1, wherein the bracket (3) is formed by die casting.