JPH0561404U - Shim replacement jig for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] Protects the camshaft from damage when the adjustment shim is replaced by the shim replacement jig. A replacement of an adjusting shim 10 detachably attached to a shim recess 9 formed on a top surface of a valve lifter 7 which is vertically moved by a cam 4 of a camshaft 3 of a direct-acting valve operating mechanism in an internal combustion engine. A jig 20 for a jig, and a tip end side of the jig is interposed between the cam shaft and the edge of the shim recess of the valve lifter, and a lifter contact portion 24 is provided so that the shim can be held at a replaceable interval. At least the lifter contact portion of this jig, which is on the camshaft side, is formed of a soft metal or polymer material.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shim replacement jig for adjusting a valve clearance in an internal combustion engine having a direct acting valve operating mechanism.

[0002]

[Prior Art]

 Conventionally, as shown in FIGS. 1 and 2, as a direct-acting type valve operating mechanism of this type, as many cams 4 as the number of valves are provided on a camshaft 3 provided in a cylinder head 1 in an ignition sequence and a valve. The camshaft 3 is rotatably supported via a cam bracket 2 and attached to the cylinder head 1 according to the opening / closing timing of the cylinder head 1 side corresponding to the cam 4 of the camshaft 3. A lifter hole 6 into which a valve lifter 7 is slidably fitted vertically is formed in the recess 1a.

The valve lifter 7 is formed in a bottomed cylindrical shape, and a shim recess 9 having a predetermined diameter and a predetermined depth is formed on the outer surface of the bottom 8 of the bottom lifter 7. The shim 10 is detachably fitted, the valve lifter 7 is slidably fitted in the lifter hole 6, and is constantly urged upward by the valve spring 11 that abuts the retainer R via the valve B. The valve (not shown) is opened and closed by the sliding contact rotation of the adjusting shim 10 with the adjusting shim 10.

The adjustment shim 10 attached to the valve lifter 7 is slidably contacted with the cam 4 and is replaced when it is out of the reference value when measuring the valve clearance. The shim replacement jig 12 used in this replacement is steel. As shown in FIGS. 3 and 4, the plate-shaped gripping portion 13 having a predetermined length and the tip end side of the gripping portion 13 are formed to be slightly thin, and the tip end side of the cylinder head 1 is A bent portion 14 is formed so as to be inserted into the recessed portion 1a and between the camshaft 3 and the valve lifter 7, and the bent portion 14 is formed in an arc shape following the edge 9a of the shim recessed portion 9 of the valve lifter 7. The cam contact portion 15 is located on the upper edge side of the bent portion 14, and a lifter contact portion 16 having a predetermined height is formed on the lower edge of the tip of the bent portion 14 so as to project.

As shown in FIG. 1, the shim exchanging jig 12 formed in this manner pushes down the valve lifter 7 against the valve spring 11 and the edge 9 a of the valve lifter 7 and the journal portion 5 of the camshaft 3. The adjusting shim 10 was exchanged while being interposed between the adjusting shim 10 and the fixing shim 10.

[0006]

[Problems to be solved by the device]

 However, since the shim exchanging jig 12 is made of a steel material, there is a problem in that the journal portion 5 of the camshaft 3 causes harmful damage such as scratches and dents.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a shim replacement jig that does not damage the camshaft.

[0008]

[Means for Solving the Problems]

 SUMMARY OF THE INVENTION In order to solve the above technical problems, the present invention is an adjustment device that is removably attached to a shim recess formed on the top surface of a valve lifter that is vertically moved by a cam of a camshaft of a direct-acting valve operating mechanism in an internal combustion engine. A jig for replacing a shim, wherein a front end side of the jig is interposed between the camshaft and an edge of a shim recess of the valve lifter so that the shim can be held at a replaceable interval. This jig exists in a shim replacement jig for an internal combustion engine, in which at least the lifter contact portion on the camshaft side of the jig is formed of a soft metal or a polymer material.

[0009]

[Action]

 With the above configuration, the camshaft can be protected from damage.

[0010]

【Example】

 An embodiment of the present invention will now be described with reference to the drawings. The shim replacement jig 20 in this embodiment is formed in substantially the same manner as the conventional jig 12, and is a plate-shaped jig having a predetermined length. The grip portion 21 and the tip end side of the grip portion 21 are formed to be slightly thin, and the tip end side is inserted into the concave portion 1a of the cylinder head 1 and the bent portion 22 is formed so as to be inserted between the cam shaft 3 and the valve lifter 7. The bent portion 22 is formed in an arc shape following the edge 9a of the shim recess 9 of the valve lifter 7, and the upper edge side of the bent portion 22 serves as a cam contact portion 23, which is located at the lower end of the tip of the bent portion 22. Is provided with a lifter contact portion 24 having a predetermined height. The cam contact portion 23 is formed of a metal softer than the material of the cam shaft 3, for example, a copper alloy.

Therefore, as in the conventional case, the shim replacement jig 20 thus formed is pressed down against the valve spring 11 against the valve spring 7 and the edge 9 a of the valve lifter 7 and the journal of the camshaft 3 are pressed. If the cam contact portion 23 made of a soft metal comes into contact with the journal portion 5 of the camshaft 3 when it is interposed between the camshaft 3 and the portion 5 and maintains a predetermined distance, the camshaft 3 is protected from damage. can do.

In the above embodiment, the cam contact portion 23 is exemplified by a metal softer than the material of the cam shaft 3, but the invention is not limited to this and may be a synthetic resin material, a synthetic rubber or the like. Alternatively, the jig 20 may be entirely made of synthetic resin.

[0013]

[Effect of the device]

 The present invention is a replacement shim for an adjustment shim that is detachably attached to a shim recess formed on the top surface of a valve lifter that is moved up and down by a cam of a camshaft of a direct drive type valve operating mechanism in an internal combustion engine. The jig has a tip end side which is interposed between the cam shaft and the edge of the shim recess of the valve lifter to form a lifter contact portion capable of holding the shim at a replaceable interval. By forming at least the cam contact portion on the cam shutter side of the lifter contact portion of this jig from a soft metal or a polymeric material, the cam shaft can be protected from damage when the shim is replaced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a shim replacement state by a shim replacement jig.

FIG. 2 is a plan view showing a shim exchange state by a shim exchange jig.

FIG. 3 is a plan view of a shim replacement jig.

FIG. 4 is a front view of a conventional shim replacement jig.

[Explanation of symbols]

 3 camshaft 4 cam 7 valve lifter 9 shim recess 9a edge 10 shim for adjustment 20 shim replacement jig 23 cam contact part 24 lifter contact part

Claims (1)

[Scope of utility model registration request] 1. An exchange shim replacement jig detachably attached to a shim recess formed on a top surface of a valve lifter which is vertically moved by a cam of a camshaft of a direct acting valve operating mechanism in an internal combustion engine. The tip side of the jig is interposed between the cam shaft and the edge of the shim recess of the valve lifter to form a lifter contact portion capable of holding the shim at a replaceable interval. A shim replacement jig for an internal combustion engine, wherein at least the lifter contacting portion of the tool on the camshaft side is formed of a soft metal or polymer material.