JP2001234711A - Method for manufacturing valve lifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce deformation in heat treatment and grinding without impairing the rigidity of a side wall part, heighten tenacity of the lower end part of the side wall part, increase the impact load, and reduce noise in using internal combustion engine. SOLUTION: The side wall 11 and the side wall 12 are integrally formed from steel material by forging, and the middle part in the direction of height of the side wall part 11 is recessed inward to form a cylindrical recessed form 13. The lower end part 11a of the side wall part 11 is bent inward in about 180-degree, and the bent edge 11b is brought into direct contact with the inner peripheral surface of the side wall part 11. A valve lifter 10 is heat-treated, and there is little gas between the edge 11b and the inner peripheral surface of the side wall part 11, so that cooling liquid for quenching is hard to enter immediately, thereby keeping quenching from entering the inside of the lower end part 11a of the side wall part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a direct-drive valve lifter used for a valve train of an internal combustion engine.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional valve lifter 100 has a cylindrical side wall 101 and a disk-shaped end wall 102 closing the upper end thereof.
Are integrally formed by forging or the like to form an inverted cup. In recent years, there has been a tendency to reduce the thickness of the side wall portion 101 in order to reduce the weight of the valve lifter corresponding to the high rotation speed of the internal combustion engine, and the rigidity of the side wall portion 101 is insufficient,
The following problems may occur.

During heat treatment (carburizing and quenching) after forging, the side wall portion 101 having insufficient rigidity is deformed by thermal stress.
In particular, since the dent-deformed portion is not ground during the grinding after the heat treatment, a black scale residue 103 is generated. Side wall 1 with insufficient rigidity due to the force received during grinding
No. 01 is deformed, the roundness and the cylindricity are reduced, and burns are generated. During the heat treatment, not only the outer peripheral surface but also the inner peripheral surface of the side wall portion 101 are carburized and quenched, so that the hardness is increased, but the toughness is reduced and the impact load is weakened. When used in an internal combustion engine, the side wall portion 101 having insufficient rigidity vibrates and generates noise.

Further, since the outer peripheral surface of the side wall portion 101 is a uniform cylindrical surface as a whole, the following problem may occur. When used in an internal combustion engine, especially when used at a low temperature where the viscosity of the oil increases, an oil film formed on the entire outer peripheral surface of the side wall portion 101 causes a malfunction of the valve lifter.

As shown in FIG. 9, a lower end portion 111a of a side wall portion 111 is formed on a microfilm of Japanese Utility Model Application No. 61-147622 (Japanese Utility Model Application Laid-Open No. 63-54806).
Lifter 110 which is thicker inward than other parts
As shown in FIG. 10, the lower end portion 121 of the side wall portion 121 is formed.
a is bent so as to form an obtuse angle inward, and a concave portion 122 in which a middle portion in the height direction of the side wall portion 121 is concaved inward.
The valve lifter 120 described above is disclosed. As described above, the lower end portion 11 which is the opening side of the side wall portions 111 and 121 is provided.
When the thickness of 1a, 121a is increased or bent inward, the section modulus increases, and thus the side wall portions 111, 121a are increased.
The rigidity can be maintained even if the wall thickness is reduced.
Therefore, the above problem can be solved. Further, when the concave portion 122 is provided on the side wall portion 121, the oil can escape to the concave portion 122 and cut the oil film, so that the above problem can be solved.

However, these valve lifters 110, 1
Even with 20, the above problem could not be solved. In addition, although the above-mentioned problem is alleviated to some extent, noise that may be heard may still occur.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, not only to reduce the deformation during heat treatment or grinding, but also to prevent the rigidity from being reduced even if the thickness of the side wall is reduced. Heat treatment does not act on the lower end of the side wall so much that it increases the toughness and can withstand impact loads.It also reduces the vibration of the side wall that occurs during use in internal combustion engines, and attaches the frequency to the ears. It is an object of the present invention to provide a method of manufacturing a valve lifter that can be changed so as not to exist.

[0008]

In order to achieve the above object, a valve lifter manufactured by the present invention is a valve lifter having a cylindrical side wall and an end wall closing an upper end of the side wall. Is bent or curved inward, and the bent or curved edge is substantially in contact with the inner peripheral surface of the side wall directly or via another material, and the height direction of the side wall is It is characterized in that the middle part includes a concave shape depressed inward. The valve lifter manufacturing method according to the present invention is directed to a method for manufacturing a valve lifter including a cylindrical side wall portion and an end wall portion closing an upper end of the side wall portion. A step of forming a concave shape by making a concave shape, and bending or bending the lower end portion of the side wall portion inward, and bending or bending the edge directly or on the inner peripheral surface of the side wall portion. A step of substantially contacting through a ring-shaped separate material along the inner peripheral surface of the side wall portion, and heat-treating the valve lifter after the both steps to form the bent or curved edge and the inner periphery of the side wall portion. A step of preventing hardening from entering the lower end portion of the side wall portion by hardly allowing a cooling liquid for hardening to enter immediately, since there is almost no gap between the side walls.

Here, the shape of the "bend or curve" is not particularly limited, and may have both the bend and the curve. The “separate material” may have a ring shape along the inner peripheral surface of the side wall portion. The material of the separate material is not particularly limited, and may be metal or non-metal. However, using a material different from that of the side wall has a higher effect of reducing vibration or changing the frequency. "Almost contact" means a state in which the gap between the bent or curved edge and the inner peripheral surface of the side wall portion is reduced to the extent that the cooling liquid for heat treatment is difficult to immediately enter. There may be a slight gap left to allow the coolant to enter if time is required.

The shape and number of the "concave shape" are not particularly limited, and the following embodiments can be exemplified. Cylindrical concave shape: A concave shape in which the middle part in the height direction of the side wall portion is depressed inward so as to be one or two or more (preferably 2 to 5) diameter-reduced cylinders. The two or more reduced diameter cylinders are arranged in the direction of the lifter center axis. Corrugated concave shape (No. 1): A concave shape in which the middle part in the height direction of the side wall portion is depressed inward so as to form one or two or more (preferably 2 to 10) annular grooves. The two or more annular grooves are arranged in the direction of the center axis of the lifter. The sectional shape of the annular groove is not particularly limited, and examples thereof include a U-shape and a V-shape. Spiral concave shape: A concave shape in which the middle part in the height direction of the side wall portion is depressed inward such that one or more parallel spiral grooves (preferably 2 to 5) are formed. The cross-sectional shape of the spiral groove is not particularly limited, and examples thereof include a U-shape and a V-shape. Frame concave shape: The middle part of the side wall in the height direction is 2 or more (2
(Preferably 10 to 10). The two or more frame-shaped concave portions are arranged in the circumferential direction of the valve lifter. The shape of the picture frame is not particularly limited,
Examples include a quadrangle, an oval, an ellipse, and a circle. Corrugated concave shape (No. 2): A concave shape in which the middle part in the height direction of the side wall portion is depressed inward so as to form two or more (preferably 4 to 20) vertical grooves. The two or more vertical grooves are arranged in the circumferential direction of the lifter. The cross-sectional shape of the vertical groove is not particularly limited.
And V-shape.

Although the area of the “concave shape” is not particularly limited,
1/12 to 3/4 of the area of the entire side wall is preferable, and 1 /
6 to 2/3 are more preferred. The concave depth of the “concave shape” is not particularly limited, but is preferably 0.5 to 5 mm,
4 mm is more preferred. The method for forming the “concave shape” is not particularly limited, and examples thereof include spinning, rolling, and pressing.

In addition, a through-hole may be provided at the concave bottom of the “concave shape”. For example, the through hole can be provided in any one of the above-described concave-shaped aspects,
In particular, it is easy to provide a through-hole in the cylindrical concave shape of the embodiment or the frame concave shape of the embodiment. The shape of the through hole is not particularly limited, and examples thereof include a square, a circle, and the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments of the present invention will be described below with reference to the drawings.

A valve lifter 1 according to the first embodiment shown in FIG.
Reference numeral 0 denotes an inverted cup shape in which a cylindrical side wall portion 11 and a disk-shaped end wall portion 12 closing the upper end thereof are integrally formed from a steel material by forging or the like. The lower end 11a of the side wall 11 is bent inward by about 180 degrees, and the bent edge 11b almost directly contacts the inner peripheral surface of the side wall 11. The middle part in the height direction (substantially the center part in this example) of the side wall part 11 includes a cylindrical concave shape 13 which is depressed inward so that the part becomes, for example, one reduced diameter cylinder.

In order to manufacture the valve lifter 10, first, the side wall portion 11 and the end wall portion 12 are integrally cold forged from a rod-shaped or coil-shaped steel material (not shown). The thickness of the side wall 11 is made as thin as possible.

Next, while rotating the side wall portion and the end wall portion 12 around the lifter center axis by a rotation mechanism (not shown),
A roller jig (not shown) is pressed against the outer peripheral surface of the side wall portion 11 so that a part of the side wall portion 11 is depressed inward.
The two reduced-diameter cylinders are spinned to form a cylindrical concave shape 13. Since the cylindrical concave shape 13 increases the section modulus, the rigidity is not impaired even if the thickness of the side wall portion 11 is small, and deformation during the next heat treatment or grinding can be reduced.

Next, without processing the lower edge of the side wall portion 11 or press-cutting or cutting as necessary, the lower end portion 11a of the side wall portion 11 is bent inward by about 180 degrees, The bent edge 11 b is brought into direct contact with the inner peripheral surface of the side wall 11. Since the section modulus is increased by this bending, the rigidity is not impaired even if the thickness of the side wall portion 11 is thin, and deformation during the next heat treatment or grinding can be reduced.

Next, the valve lifter 10 is heat-treated (here, carburized and quenched). At this time, the side wall portion 11 having high rigidity is not easily deformed. Further, since there is almost no gap between the bent edge 11b and the inner peripheral surface of the side wall 11, it is difficult for the cooling liquid for quenching to enter immediately, so that the inside of the lower end 11a is not easily quenched. For this reason, the lower end 11a
Has a high toughness and can withstand an impact load.

Next, the valve lifter 10 is finished by grinding. At this time, since the side wall portion 11 is not deformed by the heat treatment as described above, no black scale remains unlike the conventional case. Further, the rigidity of the side wall portion 11 is not easily deformed by the force received during the grinding, so that the roundness and the cylindricity do not decrease.

The valve lifter 10 has a side wall 11 inserted into the guide hole 1 of the cylinder head so as to be slidable up and down.
The end wall portion 12 that has received the sliding contact of the cam 2 is used so as to press the valve 3 downward. At this time, since the bent edge 11b is almost in contact with the inner peripheral surface of the side wall 11, the vibration of the side wall 11 is reduced or the frequency is changed, so that noise is not heard.

Further, even at the time of use at a low temperature where the viscosity of the oil becomes high, the oil escapes to the cylindrical concave shape 13 and the oil film formed on the outer peripheral surface of the side wall portion 11 can be cut. 10 can be prevented from malfunctioning.

The valve lifter 1 of the second embodiment shown in FIG.
0 is a corrugated concave shape 14 in which a portion in the height direction of the side wall portion 11 is concaved inward so as to form, for example, four annular grooves 14a.
Only in that the first embodiment is included.
The four annular grooves 14a are arranged in the direction of the center axis of the lifter.

A valve lifter 1 according to a third embodiment shown in FIG.
Reference numeral 0 differs from the first embodiment only in that a halfway portion in the height direction of the side wall portion 11 includes a spiral recessed shape 15 that is recessed inward so as to form, for example, one spiral groove.

A valve lifter 1 according to a fourth embodiment shown in FIG.
Reference numeral 0 differs from the first embodiment only in that the side wall portion 11 includes a frame recessed shape 16 that is recessed inward so as to form, for example, four frame-shaped recesses 16a in the height direction. The four frame-shaped concave portions 16a are arranged in the circumferential direction of the lifter. Although not shown in FIG. 4, the lower end of the side wall 11 is bent or the like as in the first embodiment.

A valve lifter 1 according to a fifth embodiment shown in FIG.
0 is different from the first embodiment only in that the middle part in the height direction of the side wall portion 11 includes a wavy concave shape 17 which is depressed inward so as to form, for example, eight vertical grooves 17a. 8
The two vertical grooves 17a are arranged in the circumferential direction of the lifter. Although not shown in FIG. 5, the lower end of the side wall 11 is bent or the like as in the first embodiment.

The valve lifter 1 of the sixth embodiment shown in FIG.
0 represents four through holes 1 in the concave bottom of the cylindrical concave shape 13, for example.
Only the point provided with 8 is different from the first embodiment. The through hole has the concave shape 1 in the second to fourth embodiments.
4, 15, 16, and 17 may be provided at the concave bottoms.

FIG. 7 shows a modified example of the lower end portion 11a of the side wall portion 11. (A) shows that the lower end portion 11a of the side wall portion 11 is rounded inward and the curved edge 11b is formed.
Are almost directly in contact with the inner peripheral surface of the side wall 11. (B) shows that the lower end 11a of the side wall 11 is inward about 18
In this example, the bent edge 11b is almost in contact with the inner peripheral surface of the side wall portion 11 via the separate material 20 while being bent by 0 degrees. (C) is an example in which the lower end portion 11a of the side wall portion 11 is rounded inward and the curved edge 11b is almost in contact with the inner peripheral surface of the side wall portion 11 via the separate material 20. The separate material 20 is formed of a metal material (preferably a metal material different from the side wall portion 11) in a thin ring shape along the inner peripheral surface of the side wall portion 11. The reduction effect increases.

According to the second to sixth embodiments and the modified examples described above, the same operation and effect as those of the first embodiment can be obtained.

The present invention is not limited to the above-described embodiments and modified examples. For example, as described below, the present invention can be appropriately modified and embodied without departing from the spirit of the invention. (1) The lower end of the side wall is bent inward into a triangular or quadrangular shape, and the bent edge substantially contacts the inner peripheral surface of the side wall. (2) When a space is formed between the lower end portion of the side wall portion and the inner peripheral surface of the side wall portion as shown in FIG. 7A, the space is filled with members for reducing vibration. (3) Heat treatment other than carburizing and quenching (for example, carbonitriding and quenching) should be adopted. (4) A shim (not shown) is replaceably fitted to the end wall portion 12.

[0030]

As described above in detail, according to the method for manufacturing a valve lifter according to the present invention, the rigidity is not impaired even if the thickness of the side wall is reduced, and the deformation during heat treatment or grinding is suppressed. Not only can it be reduced, but also the heat treatment does not work much on the lower end of the side wall to increase the toughness, it can be strong against impact load,
An excellent effect of reducing the vibration of the side wall portion generated when used in an internal combustion engine and changing the vibration frequency so as not to be heard can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a valve lifter according to a first embodiment, partially cut away.

FIG. 2 is a front view showing a valve lifter according to a second embodiment, partially cut away;

FIG. 3 is a front view showing a valve lifter according to a third embodiment, partially cut away;

FIG. 4 is a perspective view showing a valve lifter according to a fourth embodiment in a partially broken manner.

FIG. 5 is a perspective view showing a valve lifter according to a fifth embodiment with a part cut away.

FIG. 6 is a front view showing a valve lifter according to a sixth embodiment, partially cut away;

FIG. 7 is a partial cross-sectional view showing a modification of the lower end of the side wall in the valve lifters of the first to sixth embodiments.

FIG. 8 is a front view showing a conventional valve lifter with a part cut away.

FIG. 9 is a front view of another conventional valve lifter, partially cut away.

FIG. 10 is a partially cutaway front view of another conventional valve lifter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Valve lifter 11 Side wall part 11a Lower end part 11b Edge 12 End wall part 13 Cylindrical concave shape 14 Corrugated concave shape 14a Annular groove 15 Spiral concave shape 16 Frame concave shape 16a Frame concave portion 17 Wave concave shape 17a Vertical groove 18 Through hole 20 Separate material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B21D 53/84 B21D 53/84 Z

Claims (5)

[Claims] 1. A method for manufacturing a valve lifter having a cylindrical side wall and an end wall closing an upper end of the side wall, wherein a concave portion is formed by inwardly recessing a middle part of the side wall in a height direction. Forming, bending or bending the lower end portion of the side wall portion inward,
Bringing the bent or curved edge into direct contact with the inner peripheral surface of the side wall directly or via a separate material having a ring shape along the inner peripheral surface of the side wall; Heat treatment of the valve lifter, there is almost no gap between the bent or curved edge and the inner peripheral surface of the side wall portion, and the coolant for quenching is difficult to enter immediately, so that the inside of the lower end portion of the side wall portion is And a step of making hardening harder to occur. 2. The method according to claim 1, wherein the concave shape is a cylindrical concave shape, a wavy concave shape,
2. A spiral concave shape, a frame concave shape or a wavy concave shape.
A method for manufacturing the valve lifter according to the above. 3. The method for manufacturing a valve lifter according to claim 1, wherein the method of forming the concave shape is spinning, rolling, or pressing. 4. The method for manufacturing a valve lifter according to claim 1, wherein a through hole is provided in the concave bottom portion of the concave shape. 5. The method according to claim 1, wherein the separate material is made of a material different from that of the side wall.