JPH11200820A - Thickness control working method for valve touch protrusion of valve lifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a grinding margin for finish machining by providing high precision for rough machining. SOLUTION: A valve touch protrusion 4 is compression-deformed to an axial direction by plastic working so as to prepare a thickness between a valve touch part 4a of the valve touch protrusion 4 protruded in the inner face of an end wall part 2 of a valve lifter 1 and the outer face of the wall part 2. The plastic working is carried out by using a press machine provided with a punch plate 17 and a die plate 14 of high rigidity approaching and separating relatively, a punch 18 projected on the punch plate 17, and a spacer 19 provided replacably, and by setting the valve lifter 1 on the die plate 14 to compress the valve touch part 4 with the punch 18 by a prescribed amount when the both plates 17, 14 are approached relatively until stopped by the spacer 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve lifter used for a direct-acting valve train of an internal combustion engine, and more particularly, to a valve lifter for adjusting the thickness of the protrusion to a predetermined value. It relates to a method of processing.

[0002]

2. Description of the Related Art As shown in FIG. 8, a valve lifter 51 is formed in an inverted cup shape having an end wall portion 52 and a peripheral wall portion 53.
Is protruding. In order to cope with the valve clearance adjustment, the thickness T between the valve contact surface 54a of the valve contact projection 54 and the outer surface (cam contact surface in the illustrated example) 55 of the end wall portion 52 is set to a fine pitch (for example, 10 to 20 μm). Dozens of different types of valve lifters 51 are manufactured by jumping, and a valve lifter 51 having a thickness T matching the valve mechanism of each cylinder of the internal combustion engine is selectively used. As described above, in order to adjust the thickness T to a predetermined value different at a minute pitch, the convex portion 54 per valve is conventionally processed by the following method.

First, as shown in FIG. 9, roughing is performed by cutting the vicinity of the valve contact surface 54a of the valve contact projection 54 with a lathe. Specifically, the outer surface 55 of the end wall portion 52 is brought into contact with and stopped by the reference stopper 60, the outer periphery of the peripheral wall portion 53 is held by the chuck 56, and the valve lifter 51 is rotated around its axis. The cutting tool 57 is fed into the valve lifter 51 by feeding it in a direction perpendicular to the axis, and the vicinity of the valve contact surface 54a of the valve contact projection 54 is cut from the outer peripheral portion to the central portion. By this roughing by cutting, for example, about ten types of valve lifters 51 having different thicknesses T at small pitches are created.

Next, the valve lifter 51 is hardened to harden at least the vicinity of the valve contact surface 54a.

[0005] Next, as shown in FIG. 10, finish processing is performed by grinding the valve contact surface 54 a. Specifically, the outer periphery of the peripheral wall 53 is held by the chuck 56, and the valve lifter 51 is rotated around its axis. A rotating cylindrical grindstone 58 is fed into the valve lifter 51 by feeding it in the axial direction, and the end surface of the grindstone 58 grinds the valve contact surface 54a. By the finishing process by this grinding,
From about ten types of valve lifters 51 by the roughing,
Dozens of types of valve lifters 5 with different thicknesses T at minute pitch
Create 1.

[0006]

However, the above-mentioned method for controlling the thickness of the convex portion per valve has the following problems.

[0007] The accuracy of the rough machining by cutting (the accuracy in the thickness T direction) is desired to be as high as possible in order to reduce the subsequent grinding allowance, but is actually as low as about ± 50 μm.
This is because the thickness T, the perpendicularity, and the like are very difficult to control because the contact state between the reference stopper 60 and the outer surface 55 of the end wall portion 52 has a large variation when being held by the chuck 56. Therefore, in the finishing process by subsequent grinding,
Since it is necessary to grind the variation, the grinding margin must be increased (for example, to 100 μm or more).

In consideration of a large grinding allowance, the quenching depth at the time of quenching is increased (for example, to about 160 to 200 μm).
Quenching costs are high.

Since only the grindstone 58 smaller than the inner diameter of the peripheral wall 53 can be used for grinding, the wear of the grindstone 58 is fast. Therefore, if the grinding allowance is large as described above, the life of the grinding wheel is shortened, and the cost is increased.

At the time of roughing by cutting, a central portion of the valve contact surface 54 a is provided with a boss 59 (a small projection that is not cut).
Remains. In order to reduce the remaining bits, it is necessary not to use the worn tool 57. Therefore, the tool life is short and the cost is increased. In addition, it is necessary to take time to adjust the height of the tool bit, and the equipment operation rate is reduced.

At the time of finishing by grinding, the grindstone 58
The feed of the grindstone 58 is accelerated until immediately before the wheel comes into contact with the valve contact surface 54a, and the feed of the grindstone 58 is delayed after the grindstone 58 contacts the valve contact surface 54a. However, if there is a remaining portion as described above, the grindstone 58 during the rapid feed comes into contact with the spot 59, so that the grindstone 58 is abnormally worn. In order to prevent this abnormal wear, it is necessary to stop the rapid feed before the grindstone 58 comes into contact with the spot 59 and to feed it slowly, and the grinding time is longer by the height of the spot 59 than when there is no remaining spot. Become.

In some cases, the outer surface 55 of the end wall portion 52 may be the final ground surface for finishing. In such a case, it is necessary to increase the grinding allowance of the outer surface 55 or increase the quenching depth. was there.

An object of the present invention is to solve the above-mentioned problems, to increase the accuracy of rough machining and to reduce the grinding allowance in finishing, thereby extending the life of the grinding wheel, reducing the quenching depth, and further improving the grinding efficiency. And a thickness control method of a convex portion per valve of a valve lifter, which can reduce a grinding time at a finish processing by eliminating a remaining portion at the time of rough processing and thereby reduce a cost. It is in.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a valve lifter in which a valve contact surface of a valve contact protrusion protruding from an inner surface of an end wall and an outer surface of the end wall are provided. In the method of processing the convex portion per valve in order to adjust the thickness between them to a predetermined value, the convex portion per valve is compressed and deformed in the axial direction by plastic working.

Here, a specific method of the plastic working is not particularly limited, but a high rigidity punch plate and a die plate which can relatively approach and separate, a punch protruding from the punch plate, a punch plate and a Using a press equipped with a replaceable spacer between the die plates, set the valve lifter on the die plate so that the outer surface of the end wall abuts, and stop the punch plate and die plate with the spacer It is preferable that the punching is performed by compressing the contact portion of the valve by a predetermined amount when the nozzles are relatively approached to each other.

It is preferable that the punch is provided with a diameter-enlarging deformation restricting concave portion for restricting the area near the valve-contacting surface of the valve-contacting convex portion from expanding in the direction perpendicular to the axis.

Examples of the diameter-enlarging deformation restricting concave portion include a concave portion having a pressing inner bottom surface having a diameter substantially equal to the diameter of the valve contact surface, and a restricting inner surface having a diameter increased from the pressing bottom surface to the end surface of the punch. .

If the inner bottom surface for pressing is a concave concave surface, the contact surface of the valve can be formed into a curved convex surface.

If a ridge for forming a groove on the valve contact surface is provided on the inner bottom surface for pressing, a groove can be formed on the valve contact surface.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for thickening a convex portion per valve embodying the present invention will be described with reference to FIGS.
This will be described with reference to FIG. First, the valve lifter 1 of a rough material before the thickness control method is performed will be described. As shown in FIG. 8, the valve lifter 1 is composed of a disc-shaped end wall 2 and a cylindrical peripheral wall 3. The end wall 2 has a short cylindrical projection 4 at the center of the inner surface of the end wall 2. The thickness T1 of the end wall 2 is, for example, about 2.5 mm, and the projection height T2 of the projection 4 per valve from the inner surface of the end wall 2 is, for example, about 3 mm. Therefore, the valve contact surface 4a of the convex portion 4 and the end wall 2
Thickness (T) between the outer surface 5 (in this embodiment, the cam contact surface)
Is about 5.5 mm.

The valve lifter 1 made of a crude material is formed by forging a steel material into a valve lifter shape or pressing a steel plate into a valve lifter shape.
The upper surface of the end wall portion 2 and the lower end surface of the peripheral wall portion 3 are formed by cutting with a lathe.

Dozens of types of valve lifters having different thicknesses T at minute pitches (for example, steps of 10 to 20 μm) are manufactured from the valve lifter 1 of the coarse material in order to cope with the valve clearance adjustment. As described above, in order to adjust the thickness T to a predetermined value different at a fine pitch, the convex portion 4 per valve is processed by the following method.

(1) First, as shown in FIGS. 1 to 4, rough processing is performed by compressing and deforming the convex portion 4 of the valve in the axial direction by plastic working (press forming) using a press machine 10. .

The press 10 has a plurality of connecting columns 11
A lower plate 12 and an upper plate 13 which are connected and fixed by the above are provided, and a die plate 14 is installed at the center of the lower plate 12. A hydraulic cylinder 15 is attached downward at the center of the upper surface of the upper plate 13, a rod 16 penetrates the upper plate 13 downward, and a punch plate 17 is attached to a lower end of the rod 16. Die plate 14 and punch plate 1
7 has a high rigidity by being formed in a disk shape having a diameter of, for example, about 100 to 150 mm. Hydraulic cylinder 1
5, the die plate 14 and the punch plate 17 can relatively approach and separate from each other.

At the center of the lower surface of the punch plate 17, a cylindrical punch 18 projects downward, and at the center of the lower surface of the punch 18, the vicinity of the valve contact surface 4a of the valve contact projection 4 extends in the direction perpendicular to the axis. An enlarged deformation restricting recess 20 for restricting radial deformation is provided. Large diameter deformation restricting recess 20
The pressing inner bottom surface 21 has a diameter substantially equal to the diameter of the valve contact surface 4 a, and a conical regulating inner side surface 22 whose diameter increases from the pressing inner bottom surface 21 to the lower end surface of the punch 18. The diameter of the lower end opening of the regulating inner side surface 22 is, for example, about 0.05 to 0.2 mm larger than the diameter of the valve contact surface 4a. Die plate 14 and punch plate 17
And a spacer 19 taller than the punch 18 can be replaced with a single touch around the upper surface of the die plate 14 (for example, a convex portion provided relatively to the upper surface of the die plate 14 and the lower surface of the spacer 19). The spacer 19 of this example is formed in a flat horseshoe shape with an open front side, and has high rigidity.

In this plastic working, as shown in FIG. 3, a valve lifter 1 of a coarse material is set at the center of the upper surface of the die plate 14 so that the outer surface 5 of the end wall 2 comes into contact with the die plate 14, and FIG. As shown in the figure, the punch plate 17 is brought into contact with the upper surface of the spacer 19 by the hydraulic cylinder 15 and is lowered until it stops, and the convex portion 4 per valve is compressed by a predetermined amount by the diameter-enlarging deformation restricting concave portion 20 of the punch 18. Do.

By this plastic working, the thickness T is reduced by a predetermined amount, and the convex portion 4 per valve attempts to expand and deform in the direction perpendicular to the axis by the reduced amount. However, since the diameter expansion deformation is restricted by the boundary between the pressing inner bottom surface 21 and the restriction inner side surface 22 of the diameter expansion deformation restricting concave portion 20, the diameter of the convex portion 4 is larger than the valve contact surface 4a. The portion is deformed into a conical shape following the shape of the regulating inner side surface 22. In this way, by restricting the expansion deformation near the valve contact surface 4a, it is possible to prevent an increase in the grinding area in (3) described later.

In this roughing, the spacer 19 is replaced with a spacer having a different height, and the plastic working is performed.
For example, about ten types of valve lifters 1 having different thicknesses T at small pitches are prepared. In addition, since the spacer 19 can be replaced with one touch, it is easy to increase the number of types of the thickness T by rough processing (for example, about 20 types),
The grinding allowance can be further reduced.

(2) Next, the valve lifter 1 is quenched (not shown) to harden at least the vicinity of the valve contact surface 4a.

(3) Next, as shown in FIG. 5, finish processing is performed by grinding the valve contact surface 4a. Specifically, the outer periphery of the peripheral wall 3 is held by the chuck 6, and the valve lifter 1 is rotated around its axis. A rotating cylindrical grindstone 8 is fed into the valve lifter 1 by feeding it in the axial direction by feeding it in the axial direction, and the end face of the grindstone 8 grinds the valve contact surface 4a. By the finishing process by this grinding, dozens of types of valve lifters 1 having different thicknesses T at a fine pitch are created from about ten types of valve lifters 1 by the rough processing.

According to the thickness adjusting method of the convex portion 4 of the valve contact according to the present embodiment, the following operations and effects can be obtained.

Precision of rough working by plastic working (compression deformation) using the press machine 10 (accuracy in the thickness T direction)
Is as high as about ± 15 μm. This is die plate 1
4. By using high rigidity for the punch plate 17 and the spacer 19, the compression amount of the convex portion 4 per valve can be determined accurately, and the accuracy is improved even if the rigidity of the other parts of the press machine 10 is low. It is because it becomes high. Therefore, as compared with the accuracy of the conventional roughing by cutting of about ± 50 μm, the subsequent grinding allowance can be reduced by about 70 μm as compared with the related art. In addition, the plastic working by the press machine 10 can reduce the equipment cost and the consumable cost as compared with the cutting by the lathe, thereby reducing the cost.

Since the grinding allowance is about 70 μm smaller than before, the quenching depth can be made as shallow as possible.
The quenching cost can be reduced.

The point that only the grindstone 8 smaller than the inner diameter of the peripheral wall portion 3 can be used for grinding is the same as the conventional one, but the grinding allowance is smaller than the conventional one, so that the life of the grindstone is longer and the cost is reduced.

In the roughing by plastic working, there is no spot left on the valve contact surface 4a as in the prior art. Further, since a tool having a problem in life is not used and the punch life is very long, the cost is reduced. In addition, since a lathe that needs to be adjusted over time is not used, the equipment operation rate is high.

As described above, since there is no remaining residue, at the time of finishing by grinding, the grindstone 58 can be rapidly fed until the grindstone 8 comes into contact with the valve contact surface 4a. Therefore, the grinding time is shortened, and abnormal wear of the grindstone 8 due to the pinching does not occur.

At the time of plastic working, the above-mentioned diameter-enlarging deformation regulating recess 2 is formed.
Since the diameter expansion deformation in the vicinity of the valve contact surface 4a is regulated by 0, it is possible to prevent a subsequent increase in the grinding area, and to increase the grinding efficiency.

In some cases, the outer surface 5 of the end wall 2 may be the final ground surface of the finishing process.
The grinding allowance can be reduced and the quenching depth can be reduced.

Further, according to the method for controlling the thickness of the convex portion 4 per valve according to the present embodiment, since the accuracy of the roughing is high,
It is also possible to eliminate the need for the finishing work by the grinding of the above (3) (so-called grindingless).

The present invention is not limited to the above-described embodiment, but may be embodied with appropriate modifications without departing from the spirit of the invention, for example, as described below. (A) As shown in FIG. 6, the pressing inner bottom surface 21 is formed into a curved concave surface so that the valve contact surface 4a is formed into a curved convex surface.

(B) As shown in FIG.
1 is to form a groove 9 for oil lubrication on the valve contact surface 4a by providing the ridge 23.

(C) The diameter of the pressing inner bottom surface 21 of the diameter-enlarging deformation regulating concave portion 20 is made smaller than the diameter of the valve contact surface 4a,
During the plastic working, the vicinity of the valve contact surface 4a is reduced in diameter in the direction perpendicular to the axis.

(D) The diameter-enlarging deformation restricting recess 20 is omitted,
The central part of the lower surface of the punch 18 is flat. in this case,
At the time of roughing by plastic working, the vicinity of the valve contact surface 4a is expanded and deformed, but the accuracy is equal to or higher than that of the above embodiment. Therefore, it is particularly suitable when the grinding of the above (3) is unnecessary (grinding is not required). In addition, this plane may be the curved concave surface of (a), or the ridge of (b) may be provided on this plane.

(E) Shim (not shown) on the outer surface 5 of the end wall 2
And the surface of the shim should be the cam contact surface.

[0045]

According to the method for controlling the thickness of a convex portion per valve of a valve lifter according to the present invention, the accuracy of rough machining can be increased, the finishing allowance can be reduced, and the grinding wheel life can be extended or the quenching depth can be increased. It has the advantage of being able to make the surface shallower, and furthermore to achieve no grinding, and to eliminate the remaining bits during roughing, shorten the grinding time during finishing, and reduce costs. Play.

[Brief description of the drawings]

FIG. 1 is a front view of a press machine used for a thickness adjusting method according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view immediately before rough working by plastic working using the press machine.

FIG. 4 is a sectional view at the time of rough working by plastic working using the press machine.

FIG. 5 is a cross-sectional view at the time of finish processing by grinding after the rough processing.

FIG. 6 is a cross-sectional view showing a modification of the embodiment.

FIG. 7 is a perspective view showing another modification of the embodiment.

8A and 8B show a valve lifter to be subjected to thickness control, wherein FIG. 8A is a cross-sectional view, and FIG. 8B is an enlarged view of a circled area of FIG.

9A and 9B show rough machining by cutting in a conventional thickness adjusting method, in which FIG. 9A is a cross-sectional view, and FIG. 9B is an enlarged view of a circled area in FIG.

FIG. 10 is a cross-sectional view at the time of finish processing by grinding in a conventional thickness control processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve lifter 2 End wall part 3 Peripheral wall part 4 Valve convex part 4a Valve contact surface 5 Outer surface 9 Groove 10 Press machine 11 Connecting column 12 Lower plate 13 Upper plate 14 Die plate 15 Hydraulic cylinder 16 Rod 17 Punch plate 18 Punch 19 Spacer 20 Diameter-enlarging deformation regulating recess 21 Inner bottom surface for pressing 22 Inner surface for regulation 23 Projection

Claims (6)

[Claims] 1. A method for adjusting a thickness between a valve contact surface of a valve contact protrusion protruding from an inner surface of an end wall of a valve lifter and an outer surface of the end wall to a predetermined value. In the method of processing a convex portion, a method of adjusting the thickness of the convex portion of the valve lifter is characterized in that the convex portion of the valve is deformed in the axial direction by plastic working. 2. In the plastic working, a high-rigidity punch plate and a die plate that can be relatively approached and separated from each other, a punch protruding from the punch plate, and a replacement between the punch plate and the die plate are exchanged. Using a press equipped with a spacer provided so that the valve lifter can be set on the die plate such that the outer surface of the end wall abuts on the die lifter, and the punch plate and the die plate are relatively stopped by the spacer. 2. The method according to claim 1, wherein the punch presses the valve contact portion by a predetermined amount when the valve contact portion is closely approached. 3. The valve lifter according to claim 2, wherein the punch is provided with a diameter-enlarging deformation restricting concave portion for restricting a diameter-expanding deformation in the direction perpendicular to the axis of the vicinity of the valve contact surface of the valve contact convex portion. Thickening processing method of convex part per valve. 4. The diameter-increasing deformation restricting concave portion includes a pressing inner bottom surface having a diameter substantially equal to the diameter of the valve contact surface, and a regulating inner surface whose diameter increases from the pressing bottom surface to the end surface of the punch. 4. A method for thickness-controlling a convex portion of a valve lifter according to claim 3. 5. The method according to claim 4, wherein the inner bottom surface for pressing is a curved concave surface. 6. The pressing inner bottom surface is provided with a ridge for forming a groove in the valve contact surface.
A method for controlling the thickness of a convex portion per valve of the valve lifter according to the above.