JPS5824043Y2 - belt tensioner - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a belt tensioner that adjusts the tension of a belt.

Several belt tensioners have been proposed to adjust the tension of various belts such as engine timing belts, but they usually have complex structures, a large number of parts, troublesome adjustments, and poor serviceability. There is a problem that it is inferior.

An object of the present invention is to provide a belt tensioner that has a simple structure and allows easy adjustment of belt tension.

The present invention adjusts the tension by pressing the rotatable outer members of the bell HC and pulley into contact with each other, and a guide part is provided on the fixed base that supports the pulley, and a guide surface is provided on the inner member of the pulley. The guide portion and the guide surface cooperate to regulate the moving direction of the pulley, and the pulley is moved in a fixed direction by eccentrically rotating a cam portion of a cam member inserted in the inner member. , the pulley is fixed at a fixed position by fixing the cam member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a fixed base part for supporting a pulley formed integrally with a water pump case (not shown), and a timing lower cover 2 is attached to the fixed base part 1.

This timing lower cover 2 is partially bent to form guide portions 3, 3 located in parallel.

The direction in which the guide portions 3, 3 are arranged coincides with a pulley movement direction f, which will be described later.

4 is a pulley, which has a cylindrical inner member 5 and a plurality of balls 6.
An outer member 7 that comes into contact with a belt A such as a timing belt is rotatably fitted through the belt A.

A flat surface 8 is formed on a part of the inner wall surface of the inner member 5, that is, on the inner wall surface on the pulley moving direction side.

Furthermore, engagement recesses 9, 9 are formed on one end surface side of the inner member 5 to engage with the guide portion 3.3.

The arrangement direction of the engaging recesses 9, 9 is perpendicular to the flat surface 8, and both side walls thereof serve as guide surfaces 10, 10 that slide forward and backward on the outer surfaces of the guide sections 3, 3.

Therefore, the movement direction of the pulley 4 is restricted to one direction by the cooperative action of the guide portion 3.3 of the timing lower cover 2 and the guide surface 10.10 of the inner member 5.

11 is a cam member in which a through hole 12 is formed, and a cam portion 13
, a collar portion 14 and a head portion 15 are arranged in this order, and the cam portion 13 is eccentric with respect to the through hole 12.

As the cam member 11 rotates, the protruding portion 13a of the cam portion 13 comes into contact with the flat surface 8 of the inner member 5, presses the pulley 4, and moves it in a predetermined direction.

The flange portion 14 has a disc shape having a diameter slightly larger than the outer diameter of the inner member 5, and has a cam portion side end surface 14a of the flange portion 14.
is in contact with the other end surface 5a of the inner member 5.

The head 15 has a prismatic shape with a hexagonal cross section, and is configured so that the entire cam member 11 can be rotated using a tool such as a spanner.

A tightening bolt 16 is inserted into the through hole 12 of the cam member 11, and the tip of the threaded portion 16a is screwed into the fixed base portion 1.

Further, when the tightening bolt 16 is tightened by applying a tool such as a spanner to the head 16b having a hexagonal cross section, the collar portion 14 of the cam member 11 presses the inner member 5, and the fixed base portion 1 is tightened by the inch. The guard is configured to tighten and fix the member 5 (pulley 4) immovably.

Next, a method of adjusting belt tension using the belt tensioner will be explained.

First, in order to increase the tension of the timing belt A, the head 16b of the tightening bolt 16 and the head 1 of the cam member 11 are
A No. 5 wrench (not shown) is applied to loosen the fastening force exerted by the fastening bolt 16, allowing the cam member 11 to rotate.

Subsequently, the cam member 11 is eccentrically rotated counterclockwise in FIG. 4 by a predetermined angle.

Then, as the cam part 13 rotates, it comes into contact with the flat surface 8 of the inner member 5 and presses the flat part 8, so that the inner member 5
(Pulley 4) is moved.

In this case, since the engagement recess 9 of the inner member 5 is engaged with the fixed guide parts 3, 3, the direction of movement is restricted, and the entire pulley 4 moves in the pulley movement direction f.

Therefore, the timing belt A is stretched by the pulley 4 and the tension increases, and after the tension reaches the desired level,
While a wrench is engaged with the head 15 to hold down the cam member 11 so that it does not rotate, the tightening bolt 16 is tightened to tighten and fix the inner member 5 to the fixed base part 1.

Thus, the tension of the timing belt A is adjusted and kept substantially constant, and the timing belt A rotates.

Also, conversely, reduce the tension of timing belt A (
In this case, as in the case described above, the cam member 11 is made rotatable by loosening the tightening bolt 16.

Subsequently, when the cam member 11 is eccentrically rotated clockwise in FIG. 4, the tension of the timing bell t-A causes the cam member 11 to move in a direction opposite to the pulley movement direction f.

After the tension of the timing belt A has thus decreased to a desired value, the inner member 5 is fixed by tightening the tightening bolt 16.

After timing belt A is adjusted as described above,
The timing belt A rotates under a desired tension state, and the frictional force generated between the timing belt A and the outer member 7 causes the outer member 7 to rotate.

In the above embodiment, a part of the inner wall surface of the inner member 5 is formed into a flat surface 8 that the cam part 13 of the cam member 11 comes into contact with, so that movement of the inner member 5 due to eccentric rotation of the cam part 13 is prevented. Although the effect is enhanced, it goes without saying that the entire inner wall surface of the inner member may be a circumferential surface without providing such a flat surface.

In this case, the rotation axis of the cam member 11 and the rotation axis of the pulley 4 are not coaxial.

Further, the guide portion 3 may be integrally formed with the fixed base portion 1.

As described above, the present invention is configured so that the tension of the belt is adjusted by moving the pulley forward and backward by eccentric rotation of the cam member, so it has an extremely simple structure and the number of parts is reduced.
In addition, the adjustment is easy, and serviceability is improved, which is an excellent practical effect.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the present invention, and FIG. 1 is a front view of the belt tensioner, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line ■-■ in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. DESCRIPTION OF SYMBOLS 1... Fixed foundation part, 2... Timing lower cover, 3... Guide part, 4... Pulley, 5... Inner member, 6... Ball, 7... Outer member, 8... Flat surface, 10... Guide surface, 11... Cam member, 12 ...through hole, 13...cam part,
14...Brim portion, 15...Head, 16
...Tightening bolt.

Claims (1)

[Scope of utility model registration request] An inner member is provided with a guide surface that cooperates with a guide provided on the fixed base to regulate the direction of movement of the pulley, and an outer member is attached to the inner member via a rolling member and comes into contact with the belt. a pulley having a through hole, an inner member (a cam portion to be inserted therein and a a cam member having a flange portion, and a fastening member that is inserted into the through hole and that fastens and fixes the pulley to the fixed base portion by bringing the tail portion of the cam member into contact with the other end surface of the inner member, and A belt tensioner characterized in that the cam part is brought into contact with an inner wall surface of an inner member by rotating the cam member, and the pulley is moved along a guide part.