JPS63302112A - Tension adjusting method for timing belt - Google Patents

Abstract

PURPOSE:To prevent tension from being scattered by adjusting tension after the external force applied on a cam shaft has been taken off with each valve opened with pressure in adjusting the tension of a timing belt rotatting the cam shaft of an engine. CONSTITUTION:In adjusting the tension of a timing belt 9 on the manufacture line of an engine, an abutting arm 17 is arranged on the upper side of a rocker arm 2 first, and is pushed downward thereafter by the action of a driving section 18. This causes all valves 3 provided for the combustion chamber 4 of the engine to be pressed downward for taking thereby off the external force applied to a cam shaft 1. Then, a pulley 10 is moved by shifting the pulley support section 11 of a tensioner 12 so as to accomplish tension adjustment with a belt 14 fastened after the specified tension of the timing belt 9 is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for adjusting the tension of a timing belt that rotationally drives a camshaft of an overhead camshaft type engine.

[Conventional technology]

Generally, the tension of the timing belt is adjusted as follows.

Explaining according to FIG. 4, after the camshaft 1 is rotated to a certain set angle, the tension of the timing belt 9 is adjusted to a predetermined strength using the tensioner 12.

Alternatively, while rotating the camshaft 1, the tensioner 12
Adjust the tension to the desired strength.

[Problem that the invention seeks to solve]

However, in any of the above methods, there is a problem in that the valve spring 5 is greatly influenced by the reaction force and its tension varies.

The present invention aims to solve these problems, and aims to provide a timing belt tension adjustment method that can reliably prevent tension variations.

[Means for solving problems]

Therefore, in the timing belt tension adjustment method of the present invention, when adjusting the tension of the timing belt that rotates the engine camshaft, all the valves installed in each combustion chamber are pushed open to reduce the force applied to the camshaft. The feature is that the tension is adjusted after it is lost.

[For production]

In the timing belt tension adjustment method of the present invention described above, by pushing open all the valves, the influence of the reaction force of the valve spring is eliminated, and the timing belt can be reliably adjusted to a predetermined tension.

〔Example〕

Hereinafter, a timing belt tension adjustment method as an embodiment of the present invention will be explained with reference to the drawings.
The figure is a schematic side view of the apparatus for carrying out the method, and FIG. 2.3 is a perspective view of the abutment arm.

First, an apparatus related to the method of the present invention will be explained.

Reference numeral 1 in the figure indicates a camshaft, and reference numeral 2 indicates a rocker arm. One end of the rocker arm 2 is brought into contact with the cam 1a of the camshaft 1, and the other end is brought into contact with the upper end of the stem of the valve 3. The valve 3 is connected to the combustion chamber 4.
The valve spring 5 is provided facing the rocker arm 2 and is urged toward the rocker arm 2 above by the valve spring 5.

A sprocket 6 is attached to the camshaft 1, and a timing belt 9 is passed between it and a sprocket 7.8 of a crankshaft or the like.

Reference numeral 10 indicates a pulley, and reference numeral 11 indicates a pulley support portion, and the pulley 10 and pulley support portion 11 constitute a tensioner 12. A long hole 13 is provided in the pulley support portion 11, and the pulley 10 can be fixed at any position with a bolt 14. Further, the pulley support portion 11 is supported by the timing belt 9 by a spring 15.
It is constructed so that it is always tensioned with a constant force.

On the upper side of the rocker arm 2, there is a contact arm 17 that pushes open all the valves 3 downward via the rocker arm 2, and a drive section 18 that drives the arm 17.
and is provided.

Next, a timing belt tension adjustment method according to the present invention will be explained.

In particular, the method of the present invention is carried out on an engine production line, and the abutment arm 17 and its drive section 1 are
8 is installed on the production line.

When adjusting the tension of the timing belt 9, place the contact arm 17 above the rocker arm 2, and
Press down with 8. As a result, all the valves 3... are pushed down and no external force is applied to the camshaft 1, allowing it to rotate freely.

Next, the pulley support part 11 of the tensioner 12 is shifted to move the pulley 10 to bring the timing belt 9 to a predetermined tension, and then the bolt 14 is tightened to set the tension m.
Finish W.

By adjusting the tension of the timing belt 9 using the method described above, it is possible to eliminate the effect of external force from the valve spring 5, which was the cause of tension variations, so that the tension of the timing belt 9 can be adjusted without variations. Can be done.

The abutment arm 17 may be formed by molding as shown in FIG.
It is also conceivable to provide m and perform molding.

Furthermore, in this embodiment, the contact arm 17 and its driving portion 18 are used as means for pushing open all the valves 3 and eliminating the force applied to the camshaft 1, but the present invention is not limited to this. The above effect can be obtained by using any other means that can push open all the valves 3.

〔Effect of the invention〕

As described in detail above, the timing belt tension adjustment method of the present invention has the advantage that the timing belt tension can be easily adjusted without variation.

[Brief explanation of the drawing]

1 to 3 show a device related to the timing belt tension adjustment method of the present invention. FIG. 1 is a schematic side view thereof, and FIG. FIG. 2 is a schematic side view showing a device (engine) related to a belt tension adjustment method. 1...Camshaft, 1a...Cam, 2...Rocker arm, 3...Valve, 4...Combustion chamber, 5...Pulp spring, 6,7.8...Sprocket, 9...Timing belt, 10...・Pulley, 11...Pulley support part, 12
・・Tensioner, 13・・Slot hole, 14・・Bolt, 15
...Spring, 17.. Contact arm, 18.. Drive section of the contact arm 17. Agent Patent Attorney Yoshihiko Iinuma Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] When adjusting the tension of the timing belt that rotationally drives the camshaft of the engine, the tension is adjusted after all the valves installed in each combustion chamber are pushed open to eliminate the external force applied to the camshaft. How to adjust timing belt tension.