JPS61291708A - Valve device for engine - Google Patents

Abstract

PURPOSE:To prevent breakage by making the taper angle of the outer circumferential surface of a cotter connecting a valve spring retainer and a valve stem expand in two stages so as to disperse the stresses between the valve spring retainer and the cotter. CONSTITUTION:While a valve spring retainer 14 receiving a valve spring 15 is connected by a half-split cotter 13 provided between the valve spring retainer and a valve stem, the taper angle of the outer circumference of this cotter 13 is made in two stages so that the upper taper angle theta1 is larger than the lower taper angle theta2. Thus, the stress distribution between both becomes uniform all over the outer circumferential surfaces 13b and 13c of the cotter 13 as shown by B in the figure, and the stress concentration only at the lower end part in the conventional single taper surface and hence the breakage can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve device for an engine, and more particularly to a holding structure for a valve spring retainer.

[Prior art]

FIG. 4 shows a valve device employed in a four-stroke engine.

In this valve device, an inlet valve or an exhaust valve 1 is opened via a tappet 3 by a cam 2 mounted above. The closing operation of the valve 1 is performed by a compression coil spring 7 disposed between a valve spring retainer 4 held at the shaft end 111a of the valve 1 and the bottom surface of a tappet chamber 6 formed in the cylinder head 5. be exposed.

Incidentally, the retainer 4 of such a valve device is generally supported on the shaft end portion 1a of the valve 1 by a pair of semi-annular retainers 8 as shown in FIG. Subject to repeated loads.

Therefore, stress is concentrated at the mouth portion A of the retainer 4 shown in FIG. 5, and breakage occurs from the core portion. Shell breakage can be prevented by increasing the wall thickness of the lower part of the retainer 4 by increasing the thickness of the retainer 4, but this increases the weight of the parts, especially in cases where weight has a large effect on performance, such as motorcycles. ,
Undesirable.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a pulp device for an engine that can ensure the strength of a pulp spring retainer without increasing the weight of the retainer.

[Structure of the invention]

Therefore, in the present invention, the pressure contact surface between the valve spring retainer and the cock is formed by a tapered surface with an upper taper angle of θ1 and a lower taper angle of θ, (θ, <θ,), and the stress applied to the retainer is The above objective is achieved by dispersing K.

〔Example〕

FIG. 1 shows the main parts of a pulp apparatus according to the present invention.

In this pulp machine, the upper part of pulp 11 is rolled in a tappet chamber 12 formed in a cylinder head. The shaft end 11aK of this pulp 11 is formed with an annular groove 11b. A valve spring retainer 14 is held in this annular groove 11b via a retainer 13.

As shown in FIG. 2, the cotter 13 consists of a pair of semi-annular cotters 13a, 13a, and as shown in FIG. 3, in the assembled state, the upper outer peripheral surface 13b has a taper angle θ8, The lower outer peripheral surface 13C has a taper angle θ, (however,
θ, kuθ, ). Further, this semi-annular cock 13a has a semi-annular convex portion 13 on the upper inner circumferential surface.
d, 13d are formed.

The valve spring retainer 14 is formed to have an upper inner circumferential surface 14a having a taper angle θ1 and a lower inner circumferential surface 14b having a taper angle θ. Further, this valve spring retainer 14 has an annular notch 14C formed on its outer periphery to receive the compression coil spring 15.

In this pulp machine, a pulp spring 15 is arranged in the tappet chamber 12, and while compressing the spring 15, the valve spring retainer 14 is fitted into the shaft end 11aK of the pulp 11, and the shaft end 11a and the valve spring retainer 14 are fitted together. The valve spring retainer 14 is held at the shaft end portion 11a of the pulp 11 by interposing the valve spring retainer 13 between the spring retainer 14 and the valve spring retainer 14.

In the thus-arranged cotter 13, the upper outer peripheral surface 13b and the lower outer peripheral surface 13C are the same as the upper inner peripheral surface 14a and the lower inner peripheral surface 14b of the valve spring retainer 14.
The convex portions 13d are engaged in the annular grooves 11b of the pulp 11, respectively.

Therefore, in this pulp apparatus, even if the valve spring retainer 14 is subjected to uneven repeated loads by the pulp spring 15, those loads are received by the upper outer peripheral surface 13b and lower outer peripheral surface 13C of the cotter 13, so that as shown in FIG. 5, the stress in the valve spring retainer 14 is dispersed as indicated by reference numeral B.

In FIG. 1, reference numeral 16 indicates a tappet, and this tappet 16 is placed on the shaft end of the pulp 11, and is pressed down by a cam (not shown) as in the conventional case.

〔Effect of the invention〕

As described above, in the engine pulp device according to the present invention, the stress exerted on the valve spring retainer in contact with the cock is dispersed, so that the wall thickness of the lower opening of the valve spring retainer can be made thinner. Lighter weight can be achieved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a part of the pulp apparatus according to the present invention, FIG. 2 is a perspective view of its main parts, and FIG. 3 is an enlarged sectional view showing the assembled state of the main parts. FIG. 4 is a sectional view showing a conventional pulping device, and FIG. 5 is a sectional view showing stress concentration parts of its parts. 11...Pulp, 11a...Shaft end, llb...
Annular groove, 13... Kotta, 13a... Semi-annular cock, 13b... Upper outer circumferential surface, 13C... Lower outer circumferential surface 1
．． 13d... Convex portion, 14... Valve spring retainer, 14a... Upper inner circumferential surface, 14b... Lower inner circumferential surface, 14C... Notch, 15... Valve spring. Applicant Suzuki Jidotan Kogyo Co., Ltd. Figure 1 Figure 2 θ1 Figure 3

Claims (1)

[Claims] In the engine valve device, the valve spring retainer is held on the valve by interposing a pair of semi-annular cotters between the annular groove at the shaft end of the valve and the valve spring retainer, wherein the cotters and the valve spring retainer are connected to each other. A pulp device for an engine, characterized in that the pressure contact surface is formed by a tapered surface having an upper taper angle of Θ_1 and a lower taper angle of Θ_2 (Θ_2<Θ_1).