JPH0437203Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field] The present invention relates to a direct valve lifter.

[Conventional technology]

Conventionally, the structure of the vicinity of a valve lifter provided directly above the intake and exhaust valves of an internal combustion engine is as shown in FIG. That is, the intake and exhaust valves 1 are urged upward by the valve springs 2.
The upper end of the valve lifter 3 slides into contact with the valve lifter 3, and the upper end of the valve lifter 3 normally touches the upper surface of the valve lifter 3 through a shim 5.
It is slidably driven by the cam 4. Valve lifter 3
is in sliding contact with the inner circumferential surface of a bore 7 provided in the cylinder head 6 and is driven in the vertical direction, and is also rotatable in the circumferential direction.

Conventionally, heat-resistant and wear-resistant chromium, molybdenum steel, and the like have been frequently used for direct-type valve lifters, but steel valve lifters have had the following problems.

[Problem that the invention attempts to solve]

In other words, the cam and lifter of a steel valve lifter are both made of steel, so even if you adjust the tappet clearance with shims, etc., the metal-to-metal hammering noise occurs, which is a source of engine noise. .

Further, due to the above-mentioned noise, a large tappet clearance cannot be obtained, and the tappet clearance is not at an optimal value in terms of engine output.

Also, since it is made of steel, there are limits to how much it can be reduced in weight, and there are limits to how much inertial mass can be reduced.

Furthermore, chromium molybdenum steel and the like are difficult-to-cut materials, and the processing precision required for valve lifters is high, so processing requires a large number of man-hours. Furthermore, in order to ensure lubricity and conformability between the cam and the lifter, surface treatment such as a phosphoric acid film is also required.

In order to solve this problem, it is conceivable to construct the valve lifter with resin and to make the cross-sectional shape of the lifter skirt portion alternately large-diameter portions and small-diameter portions. However, in order to realize a resin valve lifter with such a skirt cross-sectional shape, it is necessary to solve the problem of rigidity, which is the weak point of resin, and the problem of stiffness of the lifter skirt when the large diameter part of the lifter skirt is pushed from the bore. The problem of reduced strength at the top of the valve lifter, which is affected by strain on the valve lifter, must be solved. In other words, the valve lifter is designed so that it can always rotate around its axis in order to prevent sliding contact in one place and to ensure even sliding contact, but along with this rotation, the valve lifter is The point of application of the load changes significantly,
Since the load conditions are severe, it is necessary to increase the rigidity of the valve lifter, especially at the top, where the strength has been reduced due to distortion of the lifter skirt.

This invention is a valve lifter in which the skirt part has a large diameter part and a small diameter part in order to reduce metal striking noise, reduce weight, and fit easily into the bore. The purpose is to provide a structure that increases the rigidity and strength of the top part under severe conditions.

[Means for solving problems]

The valve lifter of the present invention for achieving the above object has the following configuration. That is, in a direct type valve lifter installed directly above the intake and exhaust valves, the valve lifter is made of resin, and the outer circumferential shape of the cross section perpendicular to the axis of the lifter skirt is larger than the inner diameter of the bore in which the valve lifter slides. 1. A resin valve lifter having a shape in which portions having a large diameter and portions having a diameter smaller than the bore inner diameter are alternately provided, and further comprising a metal reinforcing material embedded in the top of the valve lifter.

[Effect]

When the valve lifter is made of resin, its rigidity is lower than that of a metal valve lifter. Furthermore, in the case where the skirt portion is provided with a large diameter portion and a small diameter portion, if the large diameter portion is pushed from the bore and the skirt portion is distorted, the strength of the valve lifter top portion will also be affected by this and the strength will be reduced. However, since the valve lifter with the above structure has a disk-shaped metal reinforcing material embedded in the top, the rigidity and strength of the top are greatly improved, and the rigidity and strength are comparable to those of metal valve lifters. will be prepared.

As described above, the valve lifter is gradually rotated about the shaft center, and the point of application of the load from the cam changes, but the metal reinforcing material is embedded so that it can withstand sufficiently in terms of rigidity and strength. Therefore, problems in terms of rigidity and strength are eliminated, and it becomes possible to realize a resin valve lifter. When using a resin valve lifter, compared to a steel valve lifter, there are various advantages such as reduced hammering noise and engine noise, reduced inertial mass of the valve lifter and increased engine output, improved sliding performance, and reduced manufacturing man-hours. The following effects can be obtained.

〔Example〕

Hereinafter, preferred embodiments of the valve lifter according to the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of the present invention. The valve lifter 11 is a direct valve lifter installed directly above the intake and exhaust valves of an internal combustion engine, and its upper surface is arranged so as to be in direct sliding contact with a cam without using a shim. The valve lifter 11 is made of resin except for a reinforcing material portion made of metal, which will be described later.

The resin constituting the valve lifter 11 is at the operating temperature.
It can withstand 200℃ and is made of PEEK (polyether).
etherketone), PAI (polyamideimide), PI
(polyimide), PPS (polyphenylene sulfide), phenol, etc. are used. Teflon and carbon may be mixed into the resin to increase sliding properties and improve wear resistance, and in order to match the thermal expansion coefficient with the aluminum alloy that is the constituent material of the cylinder head, the resin may be mixed with Teflon or carbon. It may be adjusted by mixing carbon or glass.

The valve lifter 11 has a substantially flat top portion 12.
and a cylindrical lifter skirt portion 13 extending downward from the outer periphery of the top portion 12. The resin portion of the top portion 12 and the lifter skirt portion 13 are integrally formed by resin injection molding.

A substantially disk-shaped metal reinforcing member 14 is embedded in the top portion 12 of the valve lifter 11 . The reinforcing material 14 is made of steel, for example. A portion of the outer peripheral side surface and the upper surface of the reinforcing member 14 are embedded in a resin material, and the central portion of the lower surface is exposed inside the valve lifter 11. A protrusion 15 that protrudes downward is formed in the radial center of the lower surface of the reinforcing member 14.
The upper end of the valve stem is slidably abutted on the lower surface of the protrusion 15 .

Convex portions 16 are formed on the outer circumferential portion of the reinforcing member 14 and project radially outward intermittently in the circumferential direction, and the convex portions 16 are exposed on the outer circumference of the valve lifter 11. The outer periphery of the top portion 12 and the convex portion 16 is smaller than the inner diameter of the bore 18 of the cylinder head 17 into which the valve lifter 11 is inserted, so that even if the top portion 12 and the reinforcing member 14 expand thermally, the bore 18
Care has been taken not to interfere with the inner peripheral surface of the

As shown in FIG. 3, before being inserted into the bore 18, the lifter skirt part 13 has a large diameter part 19 that is equal to or more than the inner diameter of the bore 18 and protrudes radially outward. It has an outer peripheral shape in which small diameter portions 20 having a smaller diameter than the inner diameter are alternately provided in the circumferential direction. Since the lifter skirt portion 13 is elastically deformable, when it is inserted into the bore 18,
The large diameter portion 19 is reduced in diameter and slidably fitted into the bore 18.

Next, the operation of the valve lifter configured as described above will be explained.

The valve lifter 11 is rotated about its axis, and the cam is brought into sliding contact with the upper surface of the valve lifter top portion 12 without shifting. For this reason, the point of application of the load from the cam changes, and unreasonable strain tends to occur in the top portion 12 of the valve lifter 11. However, since the reinforcing material 14 is embedded in the top portion 12, its rigidity is as high as that of a metal valve lifter, so that no deformation occurs and smooth sliding contact can be obtained as before.

The lifter skirt portion 13 has a large diameter portion 19 and a small diameter portion 2.
0, when the large diameter portion 19 is pushed from the bore 18 and the lifter skirt portion 13 is deformed, the valve lifter top portion 1 is affected by the deformation.
There is a risk that the strength of reinforcement material 2 will decrease, but reinforcing material 1
Since the top part 12 is reinforced by the parts 4 and 4, the problem of the strength of the top part 12 being reduced can be solved.

Therefore, problems with rigidity and strength are resolved,
It becomes possible to construct the valve lifter 11 from resin. In this case, the lifter skirt portion 13 is formed by injection molding of resin, and because the lifter skirt portion 13 includes a large diameter portion 19 and a small diameter portion 20, the large diameter portion 19 is elastically deformed when the valve lifter 11 is inserted into the bore 18. The deformed part escapes into the small diameter part 20 and is absorbed. In other words, the fitting is achieved by injection only, and no special external machining is required, or even if machining is added, it can be easily machined, avoiding the difficult machining that was added to the outer periphery of conventional chromolybdenum steel valve lifters. It will be done.

In this way, the resin construction of the valve lifter 11 can be easily achieved. By using the resin valve lifter 11, the sliding contact with the cam becomes a sliding contact between metal and resin, and the conventional hitting noise when there is a tappet clearance is significantly reduced, and engine noise is reduced. Furthermore, since resin is lighter than metal, the inertial mass of the valve lifter 11 is reduced, and the energy consumed in vertical movement of the valve lifter 11 is reduced, resulting in improved engine output.

Another problem when the valve lifter 11 is made of resin is heat, which is the enemy of resin, but since the convex part 16 on the outer periphery of the reinforcing material 14 is exposed on the outer periphery of the valve lifter 11, it can absorb heat easily. Heat in the center is transferred to the outer periphery by conduction and is cooled by the oil abundantly supplied to the outer periphery at the convex portion 16. Therefore, the heat of the sliding parts is absorbed by the oil, and the valve lifter 11 is kept at a relatively low temperature.
The feasibility of realizing the resin valve lifter 11 is further improved.

When embedding the reinforcing material 14, the convex portion 16 on the outer periphery
is in a meshing relationship with the resin, so the valve lifter 11
There is no peeling from the resin component in the circumferential direction, and the integration is stable.

[Effect of idea]

As is clear from the above explanation, according to the resin valve lifter of the present invention, since the metal reinforcing material is embedded in the top part, it is not affected by the deformation of the lifter skirt part, which has a large diameter part and a small diameter part. It is possible to increase the rigidity and strength of the top part, where there is concern about strength reduction, and promote the use of resin for valve lifters.

Then, the valve lifter is made of resin, and
By alternately providing large diameter parts and small diameter parts in the lifter skirt part, engine noise is reduced by reducing tappet sound, reduction of valve lifter inertial mass and thereby improving engine output, and reduction of machining by injection molding. Various effects such as ease of use and better fit to the bore can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a resin valve lifter according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a bottom view of the valve lifter in FIG. 1, and FIG. is a sectional view of an engine near a conventional valve lifter. 11... Valve lifter, 12... Top, 13...
...Lifter skirt part, 14...Reinforcement material, 16...
Convex part.

Claims (1)

[Scope of utility model registration request] In the direct type valve lifter installed directly above the intake and exhaust valves, the valve lifter is made of resin, and the outer circumferential shape of the cross section perpendicular to the axis of the lifter skirt has a diameter larger than the inner diameter of the bore in which the valve lifter slides. What is claimed is: 1. A resin valve lifter having a shape in which portions having a diameter of 1.5 mm and portions having a diameter smaller than the inner diameter of a bore are alternately provided, and further comprising a metal reinforcing material embedded in the top of the valve lifter.