JP4174138B2 - ROCKER ARM AND ROCKER ARM BODY MANUFACTURING METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rocker arm that is tilted by a cam to open and close a valve provided in a cylinder head, and more particularly to a rocker arm having a body made of sheet metal.
[0002]
[Prior art]
As a conventional rocker arm of this type, for example, the one shown in Japanese Patent Application Laid-Open No. 4-259611 is known.
[0003]
This rocker arm is called an end pivot type in which a valve is opened and closed by being tilted by a cam with one longitudinal end as a fulcrum, and has a structure in which a roller is attached to the body.
[0004]
The fuselage is formed by bending a single metal plate into a substantially U-shaped cross section, thereby providing a pair of opposing side walls and connecting walls connecting them at both ends in the longitudinal direction. A valve fitting portion into which the upper end of the valve is fitted is provided, and a pivot receiver into which the upper end of the pivot portion installed in the cylinder head is fitted into the connecting wall on the other end side in the longitudinal direction.
[0005]
The roller is rotatably supported via a support shaft with respect to a pair of side walls in the body in a state in which a part projects from a through hole provided between two connecting walls in the body.
[0006]
In this conventional example, the valve fitting portion of the fuselage is subjected to a die bending process in which the fuselage has a substantially U-shaped cross section, and then one of the connecting walls of the fuselage is pushed up to a midway in the vertical direction of the pair of side walls. It is obtained by performing a mold bending process to make it an inverted M shape.
[0007]
[Problems to be solved by the invention]
By the way, in the above-described conventional example, the valve fitting portion of the fuselage is obtained by performing an unreasonable mold bending process to bend into an inverted M-shape. For example, as shown in FIGS. 6 (a) to (c), It is pointed out that the outer surface of the bent portion between the pair of side walls 51, 52 and the connecting wall 53 is liable to cause cracks that cause a reduction in strength and sink marks that cause a reduction in shape accuracy. Incidentally, sinking leads to an increase in the occurrence rate of defective products, such as varying the width dimension W of the valve insertion portion 50.
[0008]
On the other hand, the applicant of the present invention gathers and thickens the meat portions of other regions with respect to the connecting wall 53 and sinks the lower surface of the thickened connecting wall 53 to form an inverted concave shape. The formation of the valve insertion portion 50 is considered. For example, it is considered that the inner surfaces of the pair of side walls 51 and 52 are compressed and compressed to make them thin, and the plastic fluidized meat portion associated therewith is gathered on the connecting wall 53. In that case, the thickness of the side walls 51 and 52 is thin. Therefore, there is a possibility that the rigidity is lowered. In order to avoid such a decrease in rigidity, it is necessary to take measures such as using a metal plate having a large thickness as a base material of the body or changing the design of the finished shape of the rocker arm body. Incidentally, the former measure necessitates an increase in weight, and the latter measure increases the cost for a design change. There is room for improvement here.
[0009]
In view of such circumstances, an object of the present invention is to provide a rocker arm having a shape that can avoid the occurrence of defects in the manufacturing process and a shape that can avoid an increase in weight and a design change of a finished shape.
[0010]
[Means for Solving the Problems]
A rocker arm according to the present invention is a rocker arm that is tilted by a cam to open and close a valve provided on a cylinder head, and is formed by bending a single metal plate into a substantially U shape and a pair of band-shaped opposing side walls and It has a body made of sheet metal with a connecting wall connecting them, and the thickness of the connecting wall of this body is increased by pressure compression in such a way that the periphery is sandwiched from the end face in the form of a flat plate. In addition, an inverted concave valve fitting portion is formed in the lower surface of the connecting wall.
In the rocker arm according to the present invention, preferably, the thickness of the connecting wall is formed such that one side of the metal plate is bulged.
[0011]
In this configuration, the valve insertion part of the fuselage has a structure that can be obtained by increasing the thickness of the fuselage so that defects such as cracks and sink marks that have occurred in the conventional mold bending process do not occur. In addition, the width dimension of the valve insertion portion can be managed with high accuracy. In addition, when increasing the thickness of the connecting wall, the prepared metal plate can be dealt with by setting the outer dimensions around the connecting wall large in advance. This is advantageous in that it is possible to avoid a decrease in rigidity that can occur when the thickness is compressed in the thickness direction, and it is easy to cope with an increase or decrease in the amount of meat gathering when the thickness is increased.
[0012]
The rocker arm according to the present invention preferably has a support shaft in a state in which a roller with which a cam abuts is partially protruded from a through hole provided in the middle in the longitudinal direction of the connecting wall in the middle in the longitudinal direction of the pair of side walls. It is assumed that it is supported rotatably via the.
[0013]
In this configuration, the rocker arm is limited to the configuration having the body and the roller, and the characteristic configuration of the valve insertion portion in the body is the same as that of the first invention.
[0014]
In the first method for manufacturing a rocker arm body according to the present invention , a single metal plate punched into a required shape has two sides facing each other in a region where a valve insertion portion is to be formed, in order to increase the thickness of the region. An overhanging piece to be crushed is provided, and the metal plate is crushed by pressing and compressing the both overhanging pieces in the region where the valve fitting portion is to be formed in a form sandwiched from the end face, and the plastic fluid flows accordingly. A step of gathering the portions into the region to increase the plate thickness, a step of obtaining one side of the region by depression to obtain an inverted concave valve insertion portion, and a valve insertion portion in the metal plate A step of bending the opposite sides of the region into a form that rises in the same direction as the recessed direction of the valve fitting portion to obtain a pair of side walls.
[0017]
In this configuration, since the valve insertion portion is formed by the thickening process and the depression process, defects such as cracks and sink marks that have occurred in the conventional mold bending process can be avoided, The width dimension of the valve insertion portion can be managed with high accuracy. Further, in order to thickness increasing the forming region of the valve fitting portion, because in the form collapsing projecting pieces provided in the area, which is advantageous to stabilize the finished state of the fuselage B Kkaamu.
[0018]
The first rocker arm body manufacturing method according to the present invention is crushed by pressing and compressing the periphery of the region where the valve insertion portion is to be formed from the end face in a single metal plate punched into a required shape. A step of gathering plastically flowing meat portions to the region to increase the plate thickness, a step of obtaining an inverted concave valve fitting portion by depression of one surface of the region by press working, and a valve in the metal plate A step of bending a side portion of the region where the insertion portion is provided in a form that rises in the same direction as the depression direction of the valve insertion portion to obtain a pair of side walls. It is assumed that one side of the bulge is bulged.
[0019]
In this configuration, it becomes easy to position the ceiling surface of the inverted concave valve fitting portion in the process of sinking the thickened region after thickening. This is because it is possible to specify the depression depth when the valve fitting portion is formed with the non-bulged surface of the connecting wall to be thickened as a reference position.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on embodiments shown in the drawings.
[0021]
1 to 5 show an embodiment of the present invention. FIG. 1 is a side view of a rocker arm, FIG. 2 is an exploded perspective view of the rocker arm, FIG. 3 is a plan view of the rocker arm, FIG. It is a figure which shows the manufacture procedure of.
[0022]
The rocker arm 1 shown in the figure is an end pivot type that is tilted by a cam 3 with a longitudinal end supported by a lash adjuster 2 as a fulcrum to open and close the valve 4, and includes a body 5 and a roller 6. It consists of two elements.
[0023]
The body 5 is provided with a pair of opposing side walls 7 and 8 and two connecting walls 9 and 10 by pressing a single metal plate into a substantially U-shaped section by pressing, and is provided on one end side in the longitudinal direction. An inverted concave valve fitting portion 11 that receives the upper end of the valve 4 is provided on the connecting wall 9, and a hemispherical convex pivot receiver 12 that receives the upper end of the lash adjuster 2 is provided on the connecting wall 10 on the other end in the longitudinal direction. Yes.
[0024]
The roller 6 has a support shaft 14 and a plurality of needle rollers 15 with respect to the pair of side walls 7 and 8 in the body 5 in a state in which a part projects from a through hole 13 provided between the two connecting walls 9 and 10 in the body 5. It is rotatably supported through
[0025]
This embodiment is characterized by the shape of the valve fitting portion 11 and the process of forming it, particularly in the method for manufacturing the body 5. Below, the manufacturing method of the fuselage | body 5 is demonstrated in detail.
[0026]
First, a single metal plate A is subjected to a die cutting process by press working so as to have an outer shape as shown in FIG. At this time, the through holes 13 and the insertion holes 16 and 16 of the support shaft 14 are formed in a required region, and the overhanging pieces 17 and 17 to be crushed in a subsequent thickening step are formed.
[0027]
And the formation plan area | region A1 of the valve insertion part 11 in the said metal plate A is thickened. That is, by compressing and compressing the two overhanging pieces 17 and 17 connected to the above-mentioned region A1 from the end face, the meat part that is crushed as shown in FIG. As shown in FIG.5 (c), it gathers to the said area | region A1, and plate | board thickness there is thickened (thickening process). At this time, although not shown, by pressing the upper surface of the region A1 with a mold, the region A1 is expanded only to the lower surface side.
[0028]
Next, a hemispherical convex pivot receiver 12 protruding upward on the connecting wall 10 on the other end side in the longitudinal direction of the metal plate A is obtained by performing a drawing process by pressing. In addition, you may make it perform the formation process of this pivot receptacle 12 after the formation process of the valve insertion part 11 mentioned below, and the type | mold bending process of the metal plate A. FIG.
[0029]
Thereafter, as shown in FIG. 5 (d), the area A1 where the plate thickness is first thickened is subjected to a half punching process by pressing using two molds B and C, and the area A1 is depressed upward. An inverted concave valve fitting portion 11 is formed. The ceiling surface of the valve insertion portion 11 is curved in a semicircular arc shape, and the shape here is formed by being transferred from the end surface shape of the lower mold C.
[0030]
The both side portions A2, A2 of the metal plate A thus formed are subjected to a die bending process using a die D as shown in FIG. 5 (e), thereby forming a one-dot chain line in FIG. 5 (a). Bend along the U-shape. As a result, a pair of side walls 7 and 8 and connecting walls 9 and 10 are obtained. Here, in consideration of the case where there is no room for mounting the mold D on both sides of the pivot receiver 12 when the mold D is applied to the metal plate A, the regions A2 and A2 that can become the side walls 7 and 8 in the metal plate A. Of these, both sides of the pivot receiver 12 are thin.
[0031]
By the way, the above-described forming process of the insertion hole 16 may be performed after the mold bending process of the side walls 7 and 8, and the forming process of the pivot receiver 12 is performed after the mold bending process of the both side walls 7 and 8. You may make it perform.
[0032]
As described above, the valve insertion portion 11 is obtained by a half punching process in which one connecting wall 9 is increased in thickness and recessed into an inverted concave shape. It is possible to eliminate variations in strength and shape accuracy due to defects, such as the occurrence of defects such as cracks and sink marks that have been problematic in processing. Thereby, it becomes possible to contribute to the improvement of productivity and the reduction of the manufacturing cost, such as the production yield of the body 5 being improved. Furthermore, since the inner surface of the valve insertion portion 11 is obtained by shearing accompanying the half punching process, the width dimension W can be managed with higher accuracy, and the operability of the valve 4 by the valve insertion portion 11 is stabilized. Thus, it becomes possible to contribute to the improvement of the operational stability of the valve 4.
[0033]
In the above embodiment, the metal plate A is provided with the originally unnecessary overhanging pieces 17 and 17 and the overhanging pieces 17 and 17 are crushed to increase the thickness of the one connecting wall 9. For example, as described in the conventional example, it is possible to avoid a decrease in rigidity that may occur when the side wall formation scheduled region is compressed in the plate thickness direction to be thin. For this reason, it is not necessary to use the thick metal plate A as in the conventional example, and it is advantageous in that the finished shape of the body 5 of the rocker arm 1 does not need to be changed, and the overhanging pieces 17 and 17 By adjusting the size, it becomes easy to cope with the increase and decrease of the amount of meat gathering at the time of thickening, which is advantageous in that the degree of design freedom can be expanded.
[0034]
Moreover, in the said embodiment, since it is made to bulge only the single side | surface side of one connection wall 9 about a thickening process, one side of this connection wall 9 is depressed, and the inverted concave valve insertion part 11 is made. In the process of forming, it becomes easy to position the ceiling surface of the valve insertion portion 11. This is because the depression depth when the valve fitting portion 11 is formed with the non-bulged surface of the connecting wall 9 to be thickened as a reference position can be specified.
[0035]
In addition, this invention is not limited only to embodiment mentioned above, Various application and deformation | transformation can be considered.
(1) In the above embodiment, in order to increase the thickness of the connecting wall 9, the overhanging pieces 17 and 17 are provided only on two opposing sides around the region A1 that can be the connecting wall 9 in the metal plate A. Although not shown, overhanging pieces are also provided in the side wall formation scheduled areas A2 and A2 on both sides of the area A1, and all the overhanging pieces are pressed and compressed from four directions to increase the thickness. Good.
(2) In the above embodiment, the roller 6 is supported on the support shaft 13 via a plurality of needle rollers 14, but can be rotationally supported by sliding contact without using the needle roller 14. That is, the roller 6 can be directly fitted to the support shaft 13 by a clearance fit, or can be fitted via a plain bearing such as a bush (not shown).
(3) In the above embodiment, the end pivot type rocker arm 1 is exemplified, but the present invention can also be applied to a center pivot type rocker arm (not shown).
[0036]
【The invention's effect】
In the present invention, the valve fitting portion of the fuselage is free from defects such as cracks and sink marks that have been a problem in the unreasonable mold bending process presented in the conventional example, and variations in strength and shape accuracy due to the defects. Can be eliminated. As a result, the manufacturing yield of the rocker arm body can be improved, and the productivity can be improved and the manufacturing cost can be reduced. In addition, since the width dimension of the inner surface of the valve insertion portion can be managed with high accuracy, the operability of the valve by the valve insertion portion can be stabilized, and the operation stability of the valve can be improved.
[0037]
Further, in the present invention, since the compression form when the connecting wall of the body is increased in thickness is devised, as described in the conventional example, the formation planned region of the side wall in the metal plate is compressed in the plate thickness direction to reduce the thickness. It is possible to avoid a decrease in rigidity that occurs in the case of This is advantageous in that it is not necessary to use a thick metal plate as in the conventional example, and it is not necessary to change the design of the finished shape of the rocker arm body.
[Brief description of the drawings]
1 is a side view of a rocker arm according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the rocker arm according to the embodiment. FIG. 3 is a plan view of the rocker arm. [FIG. 5] A diagram showing a manufacturing procedure of a rocker arm body [FIG. 6] An explanatory diagram for pointing out a defect of a conventional example [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rocker arm 2 Rush adjuster 3 Cam 4 Valve 5 Rocker arm fuselage 6 Rocker arm roller 7 One side wall 8 of the fuselage The other side wall 9 of the fuselage One connecting wall 10 of the fuselage The other connecting wall 11 of the fuselage 11 Valve fitting 12 14 Roller spindle

Claims (5)

A rocker arm that is tilted by a cam to open and close a valve provided on the cylinder head,
A sheet metal body formed by bending a single metal plate into a substantially U-shape and providing a pair of opposed side walls in the form of strips and a connecting wall connecting them;
The thickness of the connecting wall of the fuselage is increased by pressing and compressing the periphery of the connecting wall in the form of a flat plate sandwiched from the end face, and an inverted concave valve fitting portion that sinks into the lower surface of the connecting wall A rocker arm, characterized in that is formed. The rocker arm according to claim 1,
The rocker arm according to claim 1, wherein the connecting wall is thickened by bulging one side of the metal plate . In Rokkaa beam according to claim 1 or 2,
A roller with which a cam is in contact with the pair of side walls in the longitudinal direction is rotatably supported via a support shaft in a state of partially protruding from a through hole provided in the longitudinal direction of the connecting wall. , Rokkaa arm, characterized in that. One metal plate punched into the required shape is provided with projecting pieces to be crushed to increase the thickness of the region on two opposite sides in the region where the valve insertion portion is to be formed.
The metal plate is crushed by pressing and compressing the both protruding pieces in the region where the valve fitting portion is to be formed in a form sandwiched from the end face, and the thickness of the plate is increased by gathering the flesh portions that plastically flow together with the region. A process of
A step of obtaining an inverted concave valve fitting portion by depression of one side of the region by pressing; and
A step of obtaining a pair of side walls by bending the both side portions of the metal plate in the same direction as the recessed direction of the valve insertion portion with respect to the region where the valve insertion portion is provided. A method for manufacturing a rocker arm body. In a single metal plate punched into the required shape, the periphery of the region where the valve insertion portion is to be formed is crushed by pressure compression in a form sandwiched from the end surface, and the plastic parts flowing along with it are gathered together in the region to obtain the plate thickness A process of increasing the thickness,
A step of obtaining an inverted concave valve fitting portion by depression of one side of the region by pressing; and
A step of obtaining a pair of side walls by bending the side portions of the metal plate in the form of rising in the same direction as the recessed direction of the valve insertion portion with respect to the region where the valve insertion portion is provided,
In the thickening step, the rocker arm body manufacturing method is characterized in that one side of the metal plate is bulged.

Images