JP3674762B2 - ROCKER ARM AND METHOD OF MANUFACTURING THE BODY - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an end pivot type rocker arm provided in a valve opening / closing mechanism of an engine and a method of manufacturing the body thereof.
[0002]
[Prior art]
The end pivot type rocker arm pushes the valve at the valve receiving part at the other end in the longitudinal direction by tilting the pivot part at one end in the longitudinal direction of the body as a fulcrum when the cam rotates in conjunction with the crankshaft. This is moved up and down.
[0003]
In such a rocker arm body, a screw hole is formed in an end portion which becomes a pivot portion, and an adjustment screw is screwed into the screw hole, and this adjustment screw is supported by a tilting support portion installed in a cylinder head. I try to let them.
[0004]
[Problems to be solved by the invention]
With respect to such a rocker arm, the inventor of the present invention has made the body made of a sheet metal made from a single metal plate, and has made the plate thickness thin in order to reduce the weight. However, if the thickness of the fuselage is reduced, the length of the screw hole provided in the adjusting screw mounting portion on one end side in the longitudinal direction of the fuselage is shortened, and the number of threads for obtaining the stability of the adjustment screw cannot be secured.
[0005]
In view of this, the present inventor disclosed in Japanese Patent Laid-Open No. 7-150909, in order to cover the shortage of the length of the screw hole, the adjusting screw mounting portion is subjected to burring processing to be protruded in a cylindrical shape from the body. The rocker arm has been proposed in which a long screw hole is formed in the cylindrical portion, so that the number of screw threads can be increased as compared with the above case and the stability of the adjustment screw can be improved.
[0006]
However, in the case of the rocker arm in the above proposal, even if an attempt is made to increase the number of threads that can be formed by lengthening the cylindrical portion in order to stably hold the adjusting screw, the body is thin in the first place, so the increase in burring processing There was a limit.
[0007]
In addition, since the rocker arm body is thinned, if the cylindrical part is lengthened by burring, the thickness of the cylindrical part is reduced, so the cylindrical part is connected to the cylindrical part via an adjustment screw. Depending on the situation in which strong and weak forces are repeatedly applied, there is a possibility that the cylindrical portion may be cracked. From this point as well, there is a limit in burring to lengthen the cylindrical portion.
[0008]
Further, in the case of burring, the screw hole in the cylindrical portion is caused by a difference in thermal shrinkage due to a difference in wall thickness between the adjusting screw mounting portion and the cylindrical portion in the process of thermosetting treatment for securing rigidity to be performed thereafter. As a result of the distortion of the roundness of the hole, the adjustment screw may be loosely attached or the adjustment screw may be difficult to screw.
[0009]
Accordingly, the present invention solves the problem that a screw hole having a length that can stably hold an adjusting screw and having excellent mechanical strength is secured, and distortion of the screw hole due to thermosetting can be suppressed. Let it be an issue.
[0010]
[Means for Solving the Problems]
(1) The rocker arm of the present invention is an end pivot type rocker arm that is tilted by a cam with one end in the longitudinal direction as a tilting fulcrum and opens and closes a valve disposed on the cylinder head, and is opposed substantially in parallel. A pair of opposed side walls having at least one longitudinal end thereof joined by a connecting wall;
Before the screw holes that serve as tilting fulcrums are formed in the connecting wall of the body, the connecting wall and the connecting wall peripheral portion of the opposing side wall are subjected to press working with a thickness deviation process by plastic flow, The thickness of the periphery of the connecting wall on the opposite side wall is reduced, and the thickness of the screw hole formation scheduled region in the connecting wall is increased.
[0011]
According to the present invention, since the peripheral portion of the connecting wall is gathered together in the region where the screw hole is to be formed and the plate thickness of the region is increased, the length of the screw hole is increased and therefore formed in the region. The adjustment screw can be stably held by increasing the number of screw threads to be adjusted.
[0012]
Furthermore, because the plate thickness of the peripheral wall of the screw hole is increased, there is no possibility of cracking in the peripheral wall even if a strong force is applied to the adjustment screw, and it has excellent mechanical strength and reliability. It becomes.
[0013]
Furthermore, even if a thermosetting treatment is performed after the thickening treatment, the thickness of the peripheral wall of the screw hole is increased, so that distortion of the screw hole is suppressed, and the reliability of the stable holding of the adjustment screw is high. It has become.
[0014]
In the above, the connecting wall is disposed above a pair of opposing side walls, the body is substantially inverted U-shaped when viewed from one end in the longitudinal direction , and the width between the opposing side walls around the connecting wall is at least inserted by a roller. When it is formed narrower than that of the part, the mechanical strength of the screw hole can be increased, which is preferable.
[0015]
In the above, when an oil hole for releasing oil from the inside of the screw hole toward the roller side is formed in the thickening portion of the connecting wall, the lubricating oil in the screw hole is supported by, for example, the roller through the oil hole. This is preferable because it can be supplied to a bearing or the like for lubrication.
[0016]
(2) The rocker arm body manufacturing method of the present invention is a sheet metal body development shape in which the rocker arm body is manufactured, and at least one end side in the longitudinal direction of the pair of opposing side walls facing each other in parallel is joined by a connecting wall. And a pressing process involving a thickness variation treatment by plastic flow on the connecting wall of the fuselage in the developed shape and the connecting wall peripheral part of the opposing side wall , and the peripheral part of the connecting wall of the opposing side wall Including reducing the plate thickness, increasing the plate thickness of the screw hole formation scheduled region in the connecting wall, and forming a screw hole penetrating in the plate thickness direction in the increased thickness portion. Features.
[0017]
According to the manufacturing method of the present invention, the peripheral portion of the connecting wall is gathered together in the region where the screw hole is to be formed and the thickness of the region is increased, so that the screw hole is sufficient even if the body thickness is reduced. Unlike the burring process, it is possible to manufacture a rocker arm body having a screw hole that can stably hold the adjustment screw while ensuring strength.
[0018]
Further, according to the manufacturing method of the present invention, since the plate thickness of the peripheral wall of the screw hole is increased, there is no possibility that the peripheral wall is cracked even if a strong force acts on the adjustment screw, and the mechanical strength is high. A fuselage having excellent reliability can be manufactured.
[0019]
Further, according to the manufacturing method of the present invention, even if the thermosetting treatment is performed after the thickness increasing treatment, the plate thickness of the screw hole peripheral wall can be increased as compared with the case of burring processing. Also, a rocker arm body that can suppress the distortion of the screw hole can be manufactured.
[0020]
In the above manufacturing method of the present invention, the press-processed peripheral portion is bent at a substantially right angle with respect to the connecting wall of the unfolded body, and the body is viewed from one end in the longitudinal direction. A rocker arm body is produced in which the strength of the peripheral wall of the screw hole is further increased when a process of forming a substantially inverted U-shape and forming a width between the opposing side walls at the periphery of the connecting wall at least narrower than that of the roller insertion portion is included. This is preferable.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the present invention will be described based on embodiments shown in the drawings.
[0022]
1 to 3 show an end pivot type rocker arm according to an embodiment of the present invention. FIG. 1 is a longitudinal side view thereof, FIG. 2 is a plan view thereof, and FIG. 3 is a front view thereof.
[0023]
In these drawings, 10 is a rocker arm, 20 is a cam, 30 is an adjusting screw, 40 is a nut, 50 is an adjusting screw receiving member, and 60 is a valve.
[0024]
The illustrated rocker arm 10 has a body 13 in which both ends in the longitudinal direction of a pair of opposed side walls 11 and 11 facing substantially parallel to the longitudinal direction are integrally or separately connected by connecting walls 12a and 12b.
[0025]
A roller 14 supported between the opposing side walls 11 and 11 and in contact with the cam 20 is rotatably attached to the support shaft 15 via a bearing 16 in the middle of the body 13 in the longitudinal direction. Roller 14, in this attached state, the connecting wall 12 a, and is a state of partially projecting from the through hole 11a between 12b.
[0026]
The connecting wall 12 a on one end side in the longitudinal direction of the body 13 is formed in a chip shape separate from the body 13, and serves as a valve receiving portion that contacts the valve 60.
[0027]
The connecting wall 12b on the other end side in the longitudinal direction of the body 13 has a flat surface integrated with the body 13 and is formed with a screw hole 17 penetrating in the plate thickness direction, and the adjusting screw 30 is screwed into the screw hole 17. The adjustment screw mounting portion is used.
[0028]
The adjusting screw 30 has a nut 40 screwed onto the upper protruding portion from the body 13, and a hemispherical head portion 30a of the lower protruding portion is received by a receiving member 50 provided on the cylinder head of the engine.
[0029]
The body 13 has the hemispherical head 30 a received by the receiving concave surface of the receiving member 50 in a state where the adjustment screw 30 is adjusted by the nut 40 for the lower protrusion amount.
[0030]
The body 13 has a screw hole 17 as a tilting fulcrum.
[0031]
The rocker arm 10 of this embodiment is provided with a screw hole 17 that can stably hold the adjusting screw 30 while securing its strength even if the plate thickness is reduced in order to reduce the body 13 weight, It is characterized in that it has a structure in which the distortion of the screw hole 17 can be suppressed even if it is cured.
[0032]
Specifically, in the rocker arm 10 of this embodiment, before the screw hole 17 serving as a tilting fulcrum is formed in the connecting wall 12b of the body 13, the thickness-removal processing by plastic flow is performed on the peripheral portion 12b1 of the connecting wall 12b. Is applied, and the thickness of the screw hole formation scheduled region 12b2 in the connecting wall 12b is increased.
[0033]
With the structure described above, the rocker arm 10, since the thickness of the region wall portion of the peripheral portion 12a 1 is brought together into a screw hole formation region 12b2 of the connecting wall 12b is thickened, the body 13 is a thin Even if it exists, the screw hole 17 of the length which can raise the intensity | strength with respect to the screw hole formation plan area | region 12b2, and can hold | maintain the adjustment screw 30 stably can be formed.
[0034]
Further, in this case, since the plate thickness of the peripheral wall of the screw hole 17 is increased even if the thermosetting process is performed after the thickening process, the distortion of the screw hole 17 is suppressed, and the adjusting screw 30 is The screw hole 17 is not loosened and has high reliability for holding.
[0035]
Next, the manufacturing procedure of the body 13 of the rocker arm 10 will be described with reference to FIGS.
[0036]
Here, FIG. 4A is a plan view of the fuselage in an unfolded state for explaining the first step of the method of manufacturing the fuselage, and FIG. 4B is a line (a)-(a) in FIG. 4A. FIG. 5 (a) is a plan view of the fuselage for explaining the second step, FIG. 5 (b) is a view taken along the line (b)-(b) of FIG. 5 (a), and FIG. 6 (a). ) Is a plan view of the fuselage used for the description of the third step, FIG. 6B is a view taken along line (c)-(c) in FIG. 6A, and FIG. 7A is a description of the fourth step. FIG. 7B is a plan view of the fuselage to be provided, FIG. 7B is a plan view of the fuselage to be used for explaining the fifth step, and FIG. (B) is the (e)-(e) arrow directional view of Fig.8 (a). Moreover, FIG. 9 is sectional drawing of the principal part of the fuselage | body used for description of the formation method of an oil hole.
[0037]
A body 13 having a developed shape as shown in FIGS. 4A and 4B is obtained by punching one metal plate. A screw hole 17 is not formed in the body 13.
[0038]
Next, as shown in FIGS. 5 (a) and 5 (b), the peripheral portion 12b1 of the connecting wall 12b is subjected to pressure compression processing by press working accompanied by uneven thickness processing by plastic flow.
[0039]
By this press working, the wall portion of the peripheral portion 12b1 is plastically flowed by the pressure compression process and gathers to the screw hole formation planned region 12b2, and the plate thickness of the screw hole formation planned region 12b2 is increased and thickened.
[0040]
As a result, assuming that the initial plate thickness of the connecting wall 12b of the body 13 before the press processing in the developed shape is t0, the plate thicknesses of the peripheral portion 12b1 and the screw hole formation planned region 12b2 before the press processing are uniformly t0. However, the plate thickness of the peripheral portion 12b1 after the press working is t1 (<t0) which is thinner than the initial plate thickness t0 of the connecting wall 12b, and the plate thickness of the screw hole formation planned region 12b2 is t2 (which is thicker than the plate thickness t0). > T0).
[0041]
Next, the press-processed peripheral portion 12b1 is bent at a substantially right angle with the press-processed surfaces facing each other with respect to the connecting wall 12b of the unfolded body 13, and the body 13 is viewed from one end in the longitudinal direction. It is almost inverted U-shaped. Thereby, the body 13 shown in FIGS. 6A and 6B is obtained.
[0042]
In this case, since the opposite side wall 11 and 11 side edge part in the peripheral part 12b1 of the connection wall 12b is connected with the said opposite side wall 11 and 11 edge part, it is a screw hole formation scheduled area | region toward the opposite side edge part. It is separated from the side surface of 12b2 and has a shape separated by a distance d at the opposite end.
[0043]
In this way, if the peripheral portion 12b1 is separated from the side surface of the screw hole formation planned region 12b2, it is disadvantageous in strength, and it is easy to come into contact with and interfere with each component around the engine where the rocker arm is arranged. Therefore, as shown by the arrows in FIG. 6 (b), both peripheral portions 12b1 are pressed toward the side surface of the screw hole formation planned region 12b2, and both peripheral portions 12b1 are moved as shown in FIGS. It is made to contact | abut to the side surface of the screw hole formation plan area | region 12b2.
[0044]
Thereby, although the strength of the connecting wall 12b itself is sufficiently secured, the strength of the connecting wall 12b1 is supplementarily secured by the peripheral portion 12b1, and further interference due to contact with engine peripheral components can be prevented.
[0045]
The plate thickness of the screw hole formation planned region 12b2 of the connecting wall 12b of the body 13 manufactured in this way is sufficiently thick. Therefore, as shown in FIGS. 8 (a) and 8 (b), the screw hole formation planned region 12b2 is further increased. The screw hole 17 penetrating in the plate thickness direction can be formed, and as a result, the long screw hole 17 can be formed.
[0046]
In addition, as shown in the side cross-sectional view of FIG. 9, the connecting wall 12b is formed with a slanted oil hole 12c through which the oil is discharged from the screw hole 17 toward the roller 14 in the thickened portion.
[0047]
The slanted oil hole 12c has a conical hole 12c1, a large diameter through hole 12c2, and a small diameter through hole 12c3. The small diameter through hole 12c3 is located on the screw hole 17 side. The through-hole 12c2 having a diameter is located on the upper surface side of the connecting wall 12b.
[0048]
The small-diameter through hole 12c3 is appropriately set to have a diameter and length that can ensure the pressure of the oil to be discharged. The large-diameter through hole 12c2 is appropriately set to have a diameter that can ensure workability.
[0049]
The adjustment screw 30 has an axial oil hole 30b extending from the hemispherical head 30a to the middle part of the main body and a radial oil hole 30c communicating with the oil hole 30b. An annular groove 30d is formed in the circumferential direction passing through the oil hole 30c.
[0050]
In the state where the adjusting screw 30 is attached to the screw hole 17, oil between the hemispherical head 30a and the receiving concave surface of the receiving member 50 passes through the oil holes 30b and 30c of the adjusting screw 30, Further, the oil is supplied as lubricating oil to the cam 20 and the bearing 16 of the roller 14 through the oil hole 12c of the connecting wall 12b.
[0051]
【The invention's effect】
As described above, according to the rocker arm of the present invention, the region where the screw hole is to be formed has a structure in which the thickness of the peripheral portion of the connecting wall is gathered to increase the plate thickness. Even if it is thin, the length of the screw hole formed in the region where the screw hole is to be formed is secured sufficiently long, so that the adjustment screw can be stably held in the screw hole and the screw hole Since the peripheral wall is thickened, the screw hole strength is also improved.
[0052]
The rocker arm of the present invention also has a high mechanical strength and high reliability because there is no possibility of cracking in the peripheral wall when a strong force acts on the just screw because the thickness of the peripheral wall of the screw hole is thick. It will be a thing.
[0053]
Further, the rocker arm of the present invention has a thickened screw hole peripheral wall even if the thermosetting treatment is performed after the thickness increasing treatment, so that the distortion of the screw hole is suppressed and the reliability for stable holding of the adjustment screw is improved. Is expensive.
[0054]
In addition, according to the method for manufacturing a rocker arm body of the present invention, the thickness of the peripheral portion of the connecting wall is gathered to the area where the screw holes are to be formed and the thickness of the area is increased. Can be made sufficiently long, and a fuselage having a screw hole that can stably hold the adjustment screw while ensuring strength can be manufactured. Moreover, according to this manufacturing method, the fuselage in which the distortion of the screw hole is suppressed can be manufactured even if the thermosetting process is performed after the thickness increasing process.
[Brief description of the drawings]
FIG. 1 is a vertical side view of a rocker arm according to an embodiment of the present invention. FIG. 2 is a plan view of FIG. 1. FIG. 3 is a front view of FIG. FIG. 5B is a plan view of the fuselage used for explanation of the fuselage. FIG. 5A is a view taken along the line (a)-(a) of FIG. 5A. FIG. FIG. 6B is a plan view of the fuselage used for explaining the third step in the method of manufacturing a fuselage. FIG. 7B is a plan view of the fuselage used for the description of the fourth step in the method of manufacturing a fuselage, and FIG. FIG. 8A is a plan view of a fuselage for explaining the fifth step in the method of manufacturing a fuselage, and FIG. 8B is a plan view of (a) (e) of FIG. -(E) Arrow view FIG. 9 is a cross-sectional of the body of the main part for explaining the formation of oil holes in the fuselage of the manufacturing method Figure EXPLANATION OF REFERENCE NUMERALS
DESCRIPTION OF SYMBOLS 10 Rocker arm 11 Opposite side wall 12a, 12b Connecting wall 13 Body 14 Roller 15 Support shaft 16 Bearing 17 Screw hole 20 Cam 30 Adjustment screw 40 Nut 50 Adjustment screw receiving member 60 Valve

Claims (6)

An end pivot type rocker arm that is tilted by a cam with one end in the longitudinal direction as a tilting fulcrum and opens and closes a valve disposed in the cylinder head,
A pair of opposed side walls facing substantially parallel to each other, and having at least one longitudinal end thereof coupled by a connecting wall;
Before the screw holes that serve as tilting fulcrums are formed in the connecting wall of the body, the connecting wall and the connecting wall peripheral portion of the opposing side wall are subjected to press working with a thickness deviation process by plastic flow, A rocker arm , wherein a thickness of a peripheral portion of the connecting wall on the opposite side wall is reduced in thickness, and a thickness of a screw hole formation scheduled region in the connecting wall is increased. The rocker arm according to claim 1,
The connecting walls are arranged above a pair of opposing side walls, the body is substantially U-shaped when viewed from one end in the longitudinal direction , and the width between the opposing side walls around the connecting walls is at least wider than that of the roller insertion portion. A rocker arm characterized by being narrowly formed . The rocker arm according to claim 2,
A roller with which the cam is in contact with the longitudinal intermediate portion of the body is rotatably supported via a support shaft in a state of partially protruding from a through hole provided in the longitudinal intermediate portion of the connecting wall. The rocker arm is characterized by that. In the rocker arm according to any one of claims 1 to 3,
The rocker arm according to claim 1, wherein an oil hole for discharging oil from the inside of the screw hole toward the roller side is formed in the thickening portion of the connecting wall. A method of manufacturing a body of the rocker arm according to any one of claims 1 to 4,
Punching out a single metal plate and obtaining a developed shape of a sheet metal body formed by connecting at least one longitudinal end of the pair of opposing side walls facing in parallel with a connecting wall;
The connecting wall of the fuselage in the developed shape and the peripheral portion of the connecting wall of the opposing side wall are subjected to press working accompanied by uneven thickness treatment by plastic flow , and the thickness of the peripheral portion of the connecting wall of the opposing side wall is reduced. And increasing the thickness of the screw hole formation scheduled region in the connecting wall;
Forming a screw hole penetrating in the thickness direction in the thickened portion;
A method for manufacturing a rocker arm body. In the manufacturing method of the rocker arm fuselage according to claim 5,
Bending the press-processed peripheral portion with respect to the connecting wall of the unfolded body in the form of a substantially right angle with the pressed surfaces facing each other, and making the body substantially U-shaped when viewed from one end in the longitudinal direction , and connecting A method for manufacturing a rocker arm body, comprising a step of forming a width between opposing side walls in the periphery of a wall at least narrower than that of a roller insertion portion .

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