JPS639606A - Valve lifter - Google Patents

Abstract

PURPOSE:To achieve the reduction in weight of a valve lifter and the prevention of abrasion and separation of contacting parts by forming the contacting parts for a valve stem or the like out of the body with a composite member reinforced by a ceramic reinforcement, and further forming the body part with a light alloy. CONSTITUTION:A valve lifter 5 consists of a body 8 comprising a side wall part 6 which slides in the guide hole of a cylinder head and an upper wall part 7, and a disklike shim 9 which is fitted on the upper wall part 7. In this case, the whole of the outer circumferential part in the side wall part 6 is formed by a thin cylindrical composite member 6a in which A1 alloy being a representative light alloy is reinforced by a ceramic reinforcement. And the body 6b of the side wall part is formed by only A1 alloy. Further, the central part of the upper wall part 7 is formed by a cylindrical composite member 7a reinforced by a ceramic reinforcement, and the under surface of this composite member 7a is projected downward and is made to be the contacting part for a valve stem. And the body 7b of the inner wall part is also formed by only A1 alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a valve lifter used in an OHC valve mechanism or an HV valve mechanism of an internal combustion engine.

(Prior Art) In general, a valve lifter has a cylindrical body with a bottom, and its outer peripheral surface moves IM into the guide hole of the cylinder head, the outer surface of the upper wall serves as a cam, and the inner surface of the upper wall serves as a cam. It plays the role of transmitting the displacement of the cam to the valve while contacting the valve stem or push rod, respectively.
High wear resistance is required for the outer periphery of the body, the cam contact surface, the valve stem contact surface, the push rod contact surface, etc.

Therefore, conventional valve lifters are either (1) cast using gray cast iron or alloyed cast iron and have increased wear resistance through chill hardening or induction hardening, or (2) cold forged using low carbon steel and carburized and quenched to improve wear resistance. Those with increased abrasion resistance were common.

These valve lifters have high reliability because they have excellent strength and toughness as well as wear resistance.

(Problems to be Solved by the Invention) However, valve lifters made of cast iron or carbon steel as described above have a large specific gravity and are difficult to reduce in weight, so they tend to have a large problem opening.

In particular, recent efforts have been made to improve the performance of internal combustion engines so that they run smoothly up to high rotational speeds and generate high output. However, if a valve lifter with large inertia is used in such an internal combustion engine, A problem arises in that the cam cannot fully follow the rotation of the cam.

Therefore, in the past, attempts have been made to ensure wear resistance by forming the entire valve lifter from an aluminum alloy and applying alumite treatment, plating treatment, or other surface treatment to the surfaces such as the contact surfaces.

However, there were still problems such as the surface treatment layer still lacking in wear resistance, the surface treatment layer peeling easily, and the need for post-processing to correct dimensional changes due to surface treatment, so it was not put into practical use. is difficult and rare.

Structure of the Invention (Means for Solving the Problems) Therefore, in order to solve the above-mentioned problems, the valve lifter of the present invention has the valve stem contact portion or the push rod contact portion of the body reinforced with a ceramic reinforcement material. We took technical measures to construct the main body from a light alloy.

(Function) The main body, which occupies most of the valve lifter, is made of a light alloy with low specific gravity, and the composite member that makes up the contact area of the valve stem or push rod is also reinforced with a ceramic reinforcement material with low specific gravity. Therefore, the weight of the entire valve lifter is reduced.

In addition, the composite members that make up the valve stem abutment or the buttschrot abutment are reinforced with ceramic reinforcement and have excellent wear resistance, so these abutment areas rarely wear out. do not have.

Furthermore, since the composite member and the main body are firmly integrated or joined, there is no fear that the two will separate. Further, there is no need to perform surface treatments that cause dimensional changes on the composite member and the main body.

(First Embodiment) Hereinafter, a first embodiment in which the present invention is embodied in a direct-acting valve lifter used in various OHC valve lifters will be described with reference to FIGS. 1 to 3.

A camshaft 3 on which a cam 2 for opening the intake and exhaust valves is formed extends above the cylinder head 1 . A guide hole 4 is formed in the cylinder head 1 directly below the cam 2, and a direct-acting valve lifter 5 configured as follows is slidably inserted into the guide hole 4. There is.

That is, the valve lifter 5 of this embodiment has a body formed into an inverted bottomed cylindrical shape with a side wall portion 6 that slides within the guide hole 4 and a clay wall portion 7 that is provided slightly below the upper end of the side wall portion 6. 8, and a disk-shaped shim 9 fitted onto the upper wall portion 7.

More specifically, as shown in FIG. 1, the entire outer peripheral portion of the side wall portion 6 that directly slides against the guide hole 4 is made of aluminum alloy, which is a typical light alloy, reinforced with ceramic reinforcement. The main body 6b of the side wall portion inside the joining member 6a is formed only of the aluminum alloy.

Further, the center portion of the upper wall portion 7 is also constituted by a substantially cylindrical composite member 7a reinforced with a ceramic reinforcing material, and the lower surface of the composite member 7a protrudes slightly downward and serves as a contact portion for a valve stem, which will be described later. It has become. In addition, the same composite member 7a
The earth wall main body 7b surrounding the side wall main body 6b is formed integrally with the side wall main body 6b only from an aluminum alloy. Note that a locking recess 7C is provided on the upper surface of the composite member 7a to prevent movement during molten metal forging.

In this specification, when simply referring to the main body, the side wall main body,
It means the earth wall main body or the bottom wall main body described below.

The composite members 5a, 7a and the wall main bodies 6b, 7b in this embodiment are simultaneously and integrally formed by molten forging the aluminum alloy.

That is, the composite members 5a and 7a are an aggregate 6 of ceramic reinforcing materials preformed into a thin cylindrical shape or a substantially cylindrical shape.
1) The inside of 7D is impregnated with aluminum alloy by the pressure during molten metal forging, and is formed into a composite. At the same time, each wall main body 6b, 7b is made of the same molten aluminum alloy to form the composite member 5.
It is molded while being integrated with a and 7a.

In this example, the ceramic reinforcing material is an alumina-silica ceramic fiber made by mixing 47.3% alumina and 52.3% silica (specifically, a product name of Isolite Industries Co., Ltd.). Power Owl) is used. Further, the ceramic reinforcing material aggregates 6p, 7
P is preformed into each shape by compression molding a mixture of the same ceramic fiber and an inorganic binder.

Further, the aluminum alloy forming the wall main bodies 6b, 7b is duralumin (JIs).

A2024) is used.

Further, the shim 9 is made of chromium molybdenum steel, and the entire surface including the contact surface of the cam 2 is hardened by carburizing and quenching.

Next, an intake valve 10 (or an exhaust valve) is inserted into the cylinder head 1 so as to be openable, and the upper end of the valve stem 11 is in contact with the lower surface of the composite member 7a of the valve lifter 5.

Further, a clasp 12 is attached to the upper end of the valve stem 11, and the clasp 12 is formed into a truncated cone shape whose diameter decreases at the lower end. A valve spring retainer 13 is fitted on the outside of the stopper 12, and the tapered inner circumferential surface of the valve spring retainer 13 is in contact with the tapered outer circumferential surface of the stopper 12. Further, a valve spring 15 is mounted in a compressed state between the flange portion of the valve spring retainer 13 and a support surface 14 provided within the cylinder head 1. The valve spring 15 always urges the intake valve 10 upward, while the valve stem 11
The upper end is in contact with the lower surface of the composite member 7a of the valve lifter 5.

Next, a method of manufacturing the valve lifter 5 will be explained.

First, by compressing the alumina-silica ceramic fiber mixed with a non-purchased binder in a mold (not shown), aggregates of both ceramic reinforcing materials 6p and 7p are formed.
Each is preformed into a thin cylindrical shape or a substantially cylindrical shape.

Next, as shown in FIG. 2, an aggregate 6ρ for reinforcing the composite member 6a of the side wall portion 6 is set on the inner surface of the die 21, and a The aggregate 7p is formed on the inner bottom surface of the die 21.

At this time, by fitting the protrusion 22 on the upper surface of the knockout pin 24 into the locking recess 7C of the latter assembly 7p, the assembly 7p can be easily positioned and further prevented from moving. be able to.

Subsequently, the aluminum alloy is molten in the die 21.
is injected and the punch 23 is pushed into the same die 21 to apply hydrostatic pressure to the molten mL of aluminum alloy to perform molten metal forging.

Due to the pressure during molten metal forging, the molten aluminum and aluminum alloy impregnates the entire inside of the ceramic reinforcement aggregates 6D and 7p almost uniformly, so that the composite members 6a and 7a are formed into composites. Ru.

At the same time, the wall main bodies 6b, 7b are molded from the same aluminum alloy while being integrated with the composite members 6a, 7a.

Therefore, the boundary between the composite member 6a and the side wall main body 6b and the boundary between the composite member 7a and the upper/wall main body 7b are integrally fused and become firmly continuous.

In addition, the molten metal forging makes the rough structure of the aluminum alloy itself dense and does not cause defects such as blowholes, so that the functional properties of each wall main body 6b, 7b are also improved.

After the aluminum alloy solidifies, the knock-a-ra (~pin 2
4 is activated to release the rough profile of the body 8 formed as described above from the die 21.

Next, this rough profile is subjected to heat treatment as necessary to age harden the aluminum alloy, and is also subjected to cutting and grinding processes, and a shim 9 is fitted onto the upper wall portion 7.
The valve lifter 5 is completed.

Next, the effects of the embodiment configured as described above will be explained.

First, the main bodies 6b and 7b occupying the majority of the valve lifter 5.
is made of an aluminum alloy with a small specific gravity, and the composite members 6a and 7a are also reinforced with a ceramic reinforcement material with a small specific gravity, so that the entire valve lifter 5 is lightweight.

Therefore, the inertial mass of the valve lifter 5 can be easily reduced, and even when the internal combustion engine is operated up to a high speed range, the followability of the intake and exhaust valves can be maintained.

In addition, since the composite members f3a and 7a are reinforced with ceramic reinforcing material and have excellent wear resistance, the lower surface (valve stem contact surface) of the composite member 7a of the soil wall portion 7 is in contact with the upper end of the valve stem 11. The composite member 6a of the side wall portion 6 is hardly worn out by sliding against the guide hole 4 of the cylinder head 1.

Further, composite members 6a, 7a and each wall main body 6b.

Since it is firmly integrated with 7b, there is no need to worry about them peeling off.

Further, since there is no need to perform surface roughening such as alumite treatment or plating treatment that causes dimensional changes to the composite members 6a, 7a, etc., post-processing is also unnecessary.

(Second Embodiment) As shown in FIG. 4, a second embodiment of the present invention is a valve lifter consisting of only a body 8 without a separate shim, and includes an earth wall including a contact portion of a valve stem 11. The entire portion 7 is formed into a substantially disc-shaped composite member 7dT knee groove reinforced with a ceramic reinforcement material, and the side wall body 6b integrated with the composite member 7d is formed of an aluminum alloy. This embodiment is different from the first embodiment in that the member 6a is also used as the composite member 7d.

Therefore, this embodiment also has the same effects as the first embodiment, and since the upper surface of the composite member 7d constitutes the cam abutting portion, the abrasion resistance of that portion is also guaranteed.

(Third Embodiment) As shown in FIG. 5, the third embodiment of the present invention also includes a valve lifter consisting of only a body 8 without a separate shim, and extends from the outer periphery of the side wall 6 to the earth wall. Only in that the central part and the upper surface part of 7 are integrally constituted by a composite member 30 reinforced with a ceramic reinforcement material.
This is different from the first embodiment.

Therefore, in addition to achieving the same effects as the first embodiment, this embodiment also reduces the weight of the portion corresponding to the shim, so that not only the weight of the entire valve lifter is greatly reduced, but also the composite Since the upper surface of the member 30 constitutes the cam contact portion, there is an effect that the wear resistance of that portion is also guaranteed.

(Fourth Embodiment) Next, a fourth embodiment in which the present invention is embodied in a valve lifter used for an OHV imperial valve ei +x will be described based on FIG. 6.

A camshaft 32 on which a cam 31 for opening the intake and exhaust valves is formed extends at the lower part of the internal combustion engine, and a kite hole (not shown) is penetrated through the portion directly above the cam 31. The guide hole includes a body 35 formed into a substantially cylindrical shape with a bottom by a side wall 33 and a bottom wall 34, and a disc-shaped shim 36 fitted into the bottom wall 34. A valve lifter 37 is movably inserted.

Then, one portion of the side wall portion 33 is directly connected to the kite hole.
The entire outer peripheral part to be operated and the central part of the bottom wall part 34 that the push rod 38 comes into contact with are each composed of composite members 33a and 34a reinforced with ceramic reinforcement,
The side wall main body 33b and the bottom wall main body 34b are integrally formed by molten metal forging from the aluminum alloy.

Therefore, this embodiment has the effect that the upper surface of the composite member 34a of the bottom wall portion 34 is hardly worn out due to contact with the push rod 38, and other effects are similar to those of the first embodiment.

(Fifth Embodiment) In the fifth embodiment of the present invention, as shown in FIG. foot 4
1 is formed and a pin 42 is installed between the forks 41.
This embodiment differs from the fourth embodiment only in that the roller 43 that contacts the cam 3 is rotatably supported.

Therefore, this embodiment also has the same effect as the fourth embodiment, and also has the effect that the coefficient of friction between the cam 31 and the roller 43 is extremely low, and no problem of wear occurs between them.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIGS. 1 and 3 of the first embodiment.

In this embodiment, the composite members 6a, 7a are individually molded from metal reinforced with a ceramic reinforcement material, and the composite members 5a, 7a are each made of a light alloy.
It differs from the first embodiment only in that it is joined to b and 7b.

That is, in this embodiment, the composite member 6a is produced by (1) sintering a mixture of metal powder and a ceramic reinforcing material after compression molding, or (2) mixing a ceramic reinforcing material with molten metal and solidifying the mixture.

Only 7a is formed singly.

Then, (1) weld or adhere the same viewing parts vi6a, 7a to the separately molded wall main bodies 6b, 7b, or (2) set the same visual matching members 5a, 7a in a die to each wall main body 6.
Composite member 5 is formed by melting S@ b and 7b.
a, 7a are joined to each wall main body 6b, 7b.

Therefore, this embodiment also basically has the same effects as the first embodiment. However, according to the first embodiment, there is no need to provide a separate process for joining the composite members 6a, 7a and the wall main bodies 6b, 7b, so the first embodiment is more advantageous in this respect.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, but can be modified and embodied as desired without departing from the spirit of the invention, for example, as described below.

(1) Ceramic particles can be used as the ceramic reinforcing material in addition to the ceramic I fibers, and each of these ceramic materials can be arbitrarily selected.

For example, ceramic fibers made of zirconia, boron nitride, carbon, or other materials may be used in addition to the alumina/silica-based materials, or ceramic particles may be made of alumina, silica, silicon carbide, silicon nitride, or nitride. Materials such as boronate, titanium oxide, zirconia, carbon and others can be used.

(2) Also, regarding the light alloy forming the side wall main bodies 6b, 33b, aluminum alloy, magnesium alloy,
Various light alloys such as titanium alloy can be used, and the material is not limited to the above-mentioned duralumin (JIS, A2024).

For example, aluminum-silicon alloy (J Is, ACD
IO etc.), extra super duralumin (JIS, A7075)
etc. can be used.

(3) In the fourth and fifth embodiments, the entire bottom wall portion 34 may be made of a composite member.

(4) In the first embodiment, etc., the composite member 6a.

The method of forming 7a and each wall body 6b, 7b is not limited to molten metal forging, and various other casting methods such as die casting may also be employed.

Effects of the Invention As detailed above, the present invention not only makes it possible to reduce the weight of the valve lifter and maintain the followability of the intake and exhaust valves by reducing its inertial mass, but also
There is almost no wear or peeling of the contact part of the valve stem or the contact part of the push tip, and there is no need for post-processing, which is an excellent effect.

[Brief explanation of the drawing]

1 to 3 show a first embodiment embodying the present invention; FIG. 1 is a 11JT side view of a valve lifter; FIG. 4 is a sectional view of the valve lifter of the second embodiment, FIG. 5 is a sectional view of the valve lifter of the third embodiment, and FIG. 6 is a sectional view of the valve lifter of the fourth embodiment. FIG. 7 is a sectional view of the valve lifter of the fifth embodiment. 6... Side wall part, 6b... Side wall part body, 7... Upper wall part, 7a, 7d, 30... Composite member, 7b... Earth wall part main body, 8... Body, 11 ...Valve stem, 3
4a, 34C...Composite member, 34b...Bottom wall main body, 38...Push rod. Patent applicant Odai Iron Works Co., Ltd. Agent
Patent Attorney On 1) Hironobu No. 43! 1 i15 Diagram Flute 7

Claims (1)

[Scope of Claims] 1. A valve lifter characterized in that the valve stem contact portion or the push rod contact portion of the body is constructed of a composite member reinforced with ceramic reinforcement, and the main body is made of a light alloy. 2. The composite member is formed by impregnating a preformed ceramic reinforcing material with a light alloy, and the main body is integrally formed with the composite member from the light alloy. A valve lifter according to claim 1. 3. The composite member according to claim 1, wherein the composite member is individually molded from metal reinforced with a ceramic reinforcing material, and the composite member is joined to the main body. valve lifter. 4. The valve lifter according to claim 1, wherein the composite member constitutes a central portion of a top wall portion or a bottom wall portion of the body. 5. The valve lifter according to claim 1, wherein the composite member constitutes the entire top wall or bottom wall of the body. 6. The valve lifter according to claim 1, wherein the light alloy is an aluminum alloy, a magnesium alloy, or a titanium alloy.