JPH03172519A - Valve system for engine - Google Patents

Abstract

PURPOSE:To provide fixed contact and uniform distribution of stress by making the outer peripheral surface taper angle of a cotter engaging the shaft end of an intake valve smaller than the inner peripheral taper angle of a retainer making intimate contact with the cotter and holding a valve spring. CONSTITUTION:An intake valve 1 is axially reciprocatively journalled by a valve guide 11. A cotter 2 engages the side of the shaft end of the intake valve 1. The inner peripheral surface of a retainer 3 having the tapered surface corresponding to the outer peripheral surface of the cotter 2 and holding a valve spring 31 makes intimate contact with the outer peripheral surface of the cotter 2. The intake valve 1 and retainer 3 engagingly lock each other through the cotter 2. Thus, the taper angle of the outer peripheral surface of the cotter 2 is set smaller than the taper angle of the inner peripheral surface of the retainer 3, so that contact between the cotter 2 and retainer 3 is fixed while the distribution of stress between the cotter 2 and in take valve 1 is evened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve train for an engine made of ceramic material.

(Conventional technology) FIG. 2 shows a conventional engine valve train.

1 is an intake valve made of ceramic. The intake valve 1 is supported by a valve guide 11 so as to be able to reciprocate in the axial direction. Reference numeral 20 denotes a cock, which has the shape of a cylindrical body whose outer peripheral surface is tapered and divided into two in the axial direction. A protrusion is provided on the inner circumferential surface of the intake valve 1, and is engaged with a groove provided on the side surface of the shaft end of the intake valve 1.

A valve spring retainer 30 made of ceramic is in close contact with the outer periphery of the retainer 20. The inner circumferential surface of the valve spring retainer 30 is a tapered surface having the same angle as the outer circumferential surface of the socket 20.

The valve spring retainer 30 is the valve spring 3
1, the intake valve 1 is constantly subjected to stress in the direction of its axial end due to the reaction force of the valve spring 31. Therefore, the inner circumferential surface of the valve spring retainer 30 and the outer circumferential surface of the cock 20 are pressed against each other, and the intake valve 1 and the valve spring retainer 30 are locked together via the stopper 20.

The shaft end surface of the intake valve 1 is pushed by the cam surface of the camshaft 5 via the tappet 4, and is driven in the opening direction against the valve spring 31.

On the other hand, by forming the intake and exhaust valves from ceramic, which is a lightweight, high-strength material, or by forming the valve spring retainer from a sintered body of ceramic or aluminum alloy powder, the valve train of the intake and exhaust valves can be improved. It is known that by reducing the weight of the valve train and reducing the reciprocating inertial mass of the valve train, the allowable engine speed increases.

(Problems to be Solved by the Invention) In the case of such a conventional engine valve train device, the taper angle of the outer circumferential surface of the valve spring retainer 20 and the taper angle of the inner circumferential surface of the valve spring retainer 30 are large or small. Since the relationship is not constant, the point of contact between the holder 20 and the valve spring retainer 30 is not constant.

Therefore, the reaction force in the closing direction by the valve spring 31 is concentrated on a part of the shaft end of the intake valve 1, and especially when the intake valve 1 is made of ceramic, which is a brittle material, the stress is concentrated on the part where the stress is concentrated. Intake valve 1 as a starting point
There is a problem that it breaks.

Note that although the intake valve has been illustrated, the same problem exists for the exhaust valve as well.

The present invention has been made in view of the above points, and provides an engine valve train device that uniformizes the stress distribution between the shaft end and the side surface of the shaft end of the intake and exhaust valve, and reduces stress concentration. This is what I am trying to do.

(Means for Solving the Problems) According to the present invention, there is provided a valve spring retainer whose inner circumferential surface is a tapered surface, and whose outer circumferential surface is a tapered surface having a smaller taper angle than the inner circumferential surface of the valve spring retainer. Provided is a valve train system for an engine, characterized in that it has a lock that is interposed between the side surface of the shaft end of an exhaust valve and the inner circumferential surface of the valve spring retainer and locks the intake and exhaust valves and the valve spring retainer. Check it out.

(Function) In the engine valve train system of the present invention, the taper angle of the outer circumferential surface of the cock is made smaller than the taper angle of the inner circumferential surface of the valve spring retainer, so that the cock and the valve spring retainer come into contact with each other. is constant, and furthermore, the distribution of stress acting between the shaft and the side surface of the intake and exhaust valves is made uniform.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

It should be noted that the members having the same symbols as those in FIG. 2 above are the same, and their explanations will be omitted.

2 is a cotter similar to the cotter 20 described above, but the taper angle of the outer peripheral surface is formed to be slightly smaller.

Reference numeral 3 denotes a valve spring retainer, and the taper angle of the inner peripheral surface is formed to be slightly larger than the taper angle of the outer peripheral surface of the retainer 2. Furthermore, the wall pressure is increased compared to the valve spring retainer 30 to improve rigidity.

With the above configuration, the contact area between the holder 2 and the valve spring retainer 3 is constant at the lower part of the holder 2. When it comes into contact with the upper part, the valve spring 3
The reaction force caused by 1 concentrates on the cock groove, but when the contact occurs at the lower part as described above, the reaction force is also dispersed between the lower part of the kobuta 2 and the kotsuta groove, reducing the concentration of stress. .

Although the intake valve has been described above, it is clear that the valve train system according to the present invention can be applied to the exhaust valve as well, and various different embodiments can be easily made without departing from the spirit of the present invention. Therefore, the present invention has no limitations other than those described in the claims.
It is not limited to a particular embodiment.

(Effects of the Invention) As explained above, according to the present invention, by making the taper angle of the outer circumferential surface of the cock smaller than the taper angle of the inner circumferential surface of the valve spring retainer, the cock and the valve spring retainer can be connected to each other. Furthermore, since the distribution of stress acting between the cock and the side of the intake and exhaust valves is made uniform, the maximum and minimum values of the stress are reduced compared to conventional valve train systems. The difference is reduced by more than 60% and the average value of the stress is reduced by more than 30%, resulting in a
The allowable rotation speed which was 800 rpm was changed to 900 rpm.
It can be improved by 5% or more.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 1 is a configuration diagram showing a conventional valve train system for an engine. 1...Intake valve, 2...Kotuta, 3...Valve spring retainer, 4...Tappet, 5...Cam, 31...Valve spring.

Claims (2)

[Claims] (1) A valve spring retainer whose inner circumferential surface is a tapered surface, and whose outer circumferential surface is a tapered surface with a smaller angle than the taper angle of the inner circumferential surface of the valve spring retainer, and the side surface of the shaft end of the intake/exhaust valve and the valve spring retainer. 1. A valve train system for an engine, comprising a cotter interposed between the inner circumferential surface of the valve spring retainer and a cotter for locking the intake and exhaust valves and the valve spring retainer. (2) The engine valve train system according to claim (1), wherein the intake and exhaust valves are made of ceramic.