JP2002327605A - Sheet metal rocker arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of a screw-up part of an adjust screw 10 and a screw hole 9c, while preventing an increase of the weight, and to improve rigidity and strength of the screw hole 9c part, while preventing the interference with other structural parts to be assembled in an engine and complication of the work for fastening a lock nut 18. SOLUTION: One metal plate is pressed to manufacture a sheet metal rocker arm 14c. An end of a connecting plate part 19c forming the sheet metal rocker arm 14c is folded to form an auxiliary plate part 20. The screw hole 9c is formed, passing through the connecting plate part 19b and the auxiliary late part 20. A side wall part 2b is provided to a side of the auxiliary plate part 20, and an edge 24 of the side wall part 2b is not projected from one surface 23 of the auxiliary plate part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm for converting camshaft rotation into reciprocating motion of a valve (an intake valve and an exhaust valve) incorporated in a valve operating mechanism of an engine. The present invention relates to the improvement of a sheet metal rocker arm manufactured by applying a method.

[0002]

2. Description of the Related Art A reciprocating engine (reciprocating piston engine) is provided with an intake valve and an exhaust valve which open and close in synchronization with rotation of a crankshaft, except for a part of a two-cycle engine. In such a reciprocating engine, the movement of the camshaft that rotates in synchronization with the rotation of the crankshaft (at a rotation speed of 1/2 in the case of a four-cycle engine) is controlled by the rocker arm using the intake valve and the exhaust valve. To reciprocate the intake and exhaust valves in the axial direction.

Conventionally, a rocker arm to be incorporated in such a valve operating mechanism of an engine is generally a cast product (a cast iron product or an aluminum die-cast product). However, the cast product is heavy (in the case of a cast iron product), or has a large volume in order to secure sufficient strength (in the case of an aluminum die-cast product). In addition, since it is generally manufactured by the lost wax method, it is inevitable that the production cost increases. For this reason, in recent years, it has been considered to manufacture the rocker arm by pressing a metal plate such as a steel plate, and this has been partially implemented. Further, as one kind of such a rocker arm made of sheet metal, a structure in which an adjusting screw can be freely screwed into a screw hole formed in a part in order to finely adjust a positional relationship with an adjacent member is disclosed in, for example, Japanese Patent Application Laid-Open No. As described in JP-A-150909, it is conventionally known.

FIGS. 12 to 14 show a first example of a conventional structure described in this publication. The rocker arm 1 is formed by pressing a metal material, and a pair of substantially parallel side walls 2 and 2 provided at both ends in the width direction, and the length of the side walls 2 and 2 A screw plate portion 3 that connects one edge in the width direction (upper edge in FIG. 12) at one end in the direction (right end in FIGS. 12 to 14). That is, in the case of this example, a pair of side walls 2 and 2 and a screw plate 3 for connecting the both side walls 2 and 2 are formed by punching a metal plate as shown in FIG. After that, the side walls 2 are bent at right angles toward the near side in FIG. In addition, the other end portions in the longitudinal direction of the side walls 2 and 2 (FIG. 12)
14), the metal plate valve engaging portion 4 is bridged between them, and both end portions of the valve engaging portion 4 and the side walls 2 are welded to each other. A rocker arm 1 as shown in FIG. A pivot 5 extends between the intermediate portions of the side walls 2, 2, and a roller 7 is rotatably supported around the intermediate portion of the pivot 5 via a needle bearing 6. A short cylindrical portion 8 is formed at the center of the screw plate portion 3 by burring.
The screw hole 9 is formed in the inner peripheral surface of.

The rocker arm 1 and the roller 7 as described above
When the adjusting screw 10 is screwed into the screw hole 9, the adjusting screw 10
(A lower end in FIG. 12) is abutted against a spherical support (not shown). On the other hand, a base end surface (an upper end surface in FIG. 12) of the valve 11, which is an intake valve or an exhaust valve, abuts against one surface (the lower surface in FIG. 12) of the valve engaging portion 4. This valve 1
Numeral 1 is urged in the closing direction (upward in FIG. 12) by the valve spring 12, and is displaced in the opening direction against the elasticity of the valve spring 12 with the rocking displacement of the rocker arm 1. . Further, a cam 13 faces the outer peripheral surface of the roller 7 on the side opposite to the spherical bearing and the valve 11. When the engine is running, the cam 13
With the rotation of, the rocker arm 1 is oscillatingly displaced about the abutting portion between the adjusting screw 10 and the spherical bearing, thereby causing the valve 11 to reciprocate. The adjusting screw 10 is used to make the positional relationship between the rocker arm 1 functioning in this manner and the spherical bearing normal.

In the case of the first example of the conventional structure as described above, the weight of the rocker arm 1 is reduced while the adjusting screw 10 is
It is difficult to secure the strength of the screw hole 9 for screwing the screws. That is, when the engine is running,
, A moment load in the bending direction is applied in addition to the thrust load. Regardless of these loads, the adjusting screw 1
In order to prevent rattling at the threaded portion between the screw hole 9 and the screw hole 9, it is necessary to ensure the axial dimension of the screw hole 9 and the thickness of the portion where the screw hole 9 is formed. There is. On the other hand, when the short cylindrical portion 8 is formed by burring, the height of the short cylindrical portion 8 is limited by its inner diameter, and its thickness is limited by the thickness of the metal plate forming the rocker arm 1. Receive. For this reason, it is difficult to secure the strength of the threaded portion when the weight of the rocker arm 1 is reduced. That is, when the diameter of the short cylindrical portion 8 is increased in order to increase the height, the width of the rocker arm 1 and the diameter of the adjusting screw 10 are increased more than necessary. Further, when the thickness of the metal plate is increased to increase the thickness, the thickness of the entire rocker arm 1 becomes unnecessarily large. Any of these is not preferable because it hinders the weight reduction of the rocker arm.

As a technique for solving such inconvenience, an invention described in Japanese Patent Application Laid-Open No. 2001-59407 is known. FIGS. 15 and 16 show a rocker arm 14 made of sheet metal constructed according to the invention described in this publication. This sheet metal rocker arm 14, which is a second example of the conventional structure, includes a rocker arm main body 15 made of a metal plate of the same kind, such as a carbon steel plate, and a nut plate 16. Rocker arm body 15 of these
Is made by pressing one metal material,
It comprises a pair of side walls 2a, 2a substantially parallel to each other, and connecting plates 19a, 19b connecting one end in the width direction (upper end in FIG. 16) of these side walls 2a, 2a. In other words, by bending both end portions in the width direction of both connecting plate portions 19a and 19b, the pair of side wall portions 2a and 2a substantially parallel to each other are formed.

When the rocker arm main body 15 is manufactured, first, a metal plate is punched by a press, and
A material in which both ends of the pair of side walls 2a, 2a at one end in the width direction are connected to each other by the connection plates 19a, 19b. Thereafter, this material is transferred to each of the connecting plate portions 19a, 1
The rocker arm body 15 as shown in FIGS. 15 and 16 is bent at a right angle in the same direction at a continuous portion of the side walls 9a and the side walls 2a and 2a. At positions where the side walls 2a and 2a are aligned with each other, circular holes 17 and 17 for supporting both ends of the pivot 5 (see FIG. 12) for supporting the roller 7 are provided with each other. Form concentrically. The connecting plate 19a at one end (the right side in FIGS. 15 to 16) of the connecting plates 19a and 19b is a valve engaging portion for abutting the base end of the valve 11 (see FIG. 12). And On the other hand, the connecting plate portion 19b on the other end side (the left end side in FIGS. 15 to 16) is a screw plate portion for screwing the adjusting screw 10 (see FIG. 12).

In order to make the connection plate portion 19b a screw plate portion,
In the case of the second example of the conventional structure, the nut plate 16 is superimposed on the connecting plate portion 19b, and is fixed to the rocker arm body 15 by welding or brazing. Then, a screw hole 9a for screwing the adjusting screw 10 is formed in a state of being bridged between the nut plate 16 and the connecting plate portion 19b.

According to the rocker arm 14 made of sheet metal of the second example of the conventional structure having the above-described structure, the screw hole 9 is formed irrespective of the thickness of the metal plate constituting the rocker arm body 15 and the diameter of the screw hole 9a. 9a length and this screw hole 9a
The thickness of the metal part existing on the outer diameter side of the metal part can be secured. That is,
By increasing the thickness of the nut plate 16, the length of the screw hole 9a can be secured.
The thickness of the metal part existing on the outer diameter side of the screw hole 9a can be secured by increasing the outer diameter of the screw hole 9a.

However, in the case of the rocker arm made of sheet metal of the second example of the conventional structure which is constructed and operates as described above, the rocker arm body 15 and the nut plate 16 need to be welded or brazed. Increase. Particularly, in order to secure the strength of the welded portion or the brazed portion, it is necessary to carefully perform the welding operation or the brazing operation.

[0012]

DESCRIPTION OF THE PRESENT INVENTION In view of such circumstances, the present applicant has first made an invention relating to a sheet metal rocker arm as shown in FIGS. 17 to 21 in order to reduce the manufacturing cost of the sheet metal rocker arm. Filed (Japanese Patent Application No. 11-309040)
issue). 17 and 18 show a rocker arm 14a made of sheet metal according to a first example of the structure according to the prior invention. This first
In the example rocker arm 14a made of sheet metal, the other end (FIG. 17)
The auxiliary plate 20 is superimposed on one surface (the upper surface in FIG. 18) of the connecting plate 19b on the left end side of FIG. The auxiliary plate portion 20 is arranged such that the auxiliary plate portion 20 is overlapped with the connecting plate portion 19b on the other end side in the thickness direction.
9b is formed by folding one end in the length direction (the left end in FIGS. 17 and 18) into a hairpin shape. In the case of this example, the auxiliary plate portion 20 is densely overlapped with the connecting plate portion 19b. The auxiliary plate 20 and the connecting plate 19b
The screw holes 9b that are concentric with each other are formed at positions that match each other. The operation for forming the screw hole 9b is as follows.
This is performed after the auxiliary plate portion 20 and the connection plate portion 19b are overlapped.

According to the sheet metal rocker arm 14a of the present embodiment having the above-described configuration, regardless of the thickness of the metal plate constituting the sheet metal rocker arm 14a and the diameter of the screw hole 9b, the screw hole 9b is formed. The length and the thickness of the metal part existing on the outer diameter side of the screw hole 9b can be secured. That is, the length L _9b of the screw hole 9b can be made twice (L _9b = 2T) the thickness T of the metal plate. Further, the thickness of the metal part existing on the outer diameter side of the screw hole 9b can be freely set (within a range where the sheet metal rocker arm 14a does not increase in size) regardless of the thickness T and the diameter of the screw hole 9b. Can be set. For this reason, the weight of the sheet metal rocker arm 14a can be reduced, and the strength of the screwing portion between the screw hole 9b and the adjusting screw 10 can be improved. In addition, since it is not necessary to weld or braze different parts, cost can be reduced by simplifying the manufacturing process and product inspection.

In order to prevent the auxiliary plate portion 20 and the connecting plate portion 19b from shifting from each other, welding or brazing is performed between the leading edge of the auxiliary plate portion 20 and the connecting plate portion 19b. Things are also possible. However, even in this case, the strength required for the welded portion and the brazed portion is low, and even if the welded portion or the brazed portion is broken, there is a low possibility that a serious failure will be caused. Therefore, the trouble of welding or brazing is not particularly troublesome, and there is no need to perform a 100% inspection. The structure other than the portion where the screw hole 9b is provided in the connection plate portion 19b is the same as that of the second example of the conventional structure shown in FIGS.

Next, FIGS. 19 and 20 show a second example of the structure according to the prior invention. Rocker arm 1 made of sheet metal of this example
In the case of 4b, the connecting plate 19b and the auxiliary plate 20 are separated from each other. That is, the auxiliary plate 20 is formed by folding one end of the connecting plate 19b in the length direction (the left end in FIGS. 19 to 20) into a U-shape. The curved portion 21 for connecting the connecting plate portion 19b and the auxiliary plate portion 20 is formed in a semi-cylindrical shape having a larger radius of curvature than in the case of the first example described above, and the connecting plate portion 19b and the auxiliary plate portion are formed. 20 are arranged in parallel with each other while being separated from each other. The auxiliary plate 20 and the connecting plate 1
9b, the screw holes 9 concentric with each other
c, 9c. In addition, these two screw holes 9c, 9
c, the auxiliary plate 20 and the connecting plate 19
b) after the arrangement in the predetermined positional relationship.

In the case of this embodiment, the screw holes 9 are used.
c, 9c, the supporting span of the adjusting screw 10 (L
By increasing the length of ₁₀ ), the support rigidity of the adjusting screw 10 against the moment load applied during operation of the engine can be improved. That is, in order to increase the support rigidity of the adjusting screw 10 with respect to the moment load, the axial dimension of the threaded portion between the adjusting screw 10 and the screw holes 9c (9c) is determined. It is effective to increase the interval). In this case,
The only auxiliary plate portions 20 min were separated and the connecting plate portion 19b (the distance D min in Figure 19), and larger than that of the first example described above the support span L _10, improvement of the supporting rigidity Can be achieved.

Next, FIG. 21 shows a third embodiment of the structure according to the invention.
An example is shown. In the case of this example, the tip (the right end in FIG. 21) of the auxiliary plate 20 is abutted against one surface (the upper surface in FIG. 21) of the connecting plate 19b in order to further improve the support rigidity. For this reason, in the case of this example, the auxiliary plate 2
A bent portion 22 bent toward the connecting plate portion 19b is formed at the leading end of the connecting plate portion 19b, and the leading edge of the bent portion 22 is abutted against one surface of the connecting plate portion 19b.

In the case of the present embodiment constructed as described above, the auxiliary plate portion 20 and the connecting plate portion 19b are less likely to shift in the plane direction than in the case of the second example described above. Therefore, the support rigidity of the adjusting screw 10 (see FIG. 20) screwed into the screw holes 9c formed in the auxiliary plate portion 20 and the connecting plate portion 19b can be further improved. In order to further enhance the effect of improving the support rigidity, a butt portion between the leading edge of the bent portion 22 and one surface of the connecting plate portion 19b may be joined by welding or brazing. However, this welding or brazing may be partial, such as spot welding.

[0019]

In the case of the structure according to the prior invention shown in FIGS. 17 to 21 described above, when it is necessary to ensure a higher rigidity, for example, when it is intended to be incorporated into a high-output engine. It is desired to improve the following points. That is, large output (especially high-speed rotation type)
The engine is a valve spring 1 that presses a valve 11.
2 (see FIG. 12), the adjusting screw 1
0 (see FIG. 20), the thrust load and the moment load applied to the connecting plate portion 19b and the auxiliary plate portion 20 also increase. Regardless of such a large thrust load and moment load, in order to prevent the connecting plate portion 19b and the auxiliary plate portion 20 from being deformed, the section modulus of the connecting plate portion 19b and the auxiliary plate portion 20 must be increased. There is a need to.

In order to increase the section modulus of this part,
A pair of side walls 2 formed on both sides in the width direction of the connecting plate 19b
It is conceivable that a and 2a are extended further to the side of the screw hole 9c into which the adjusting screw 10 is screwed and further to the left than the state shown in FIGS. However, FIG.
When the pair of side walls 2a, 2a is extended to the side of the screw hole 9c (as in the first example of the conventional structure shown in FIGS. 12 and 13), the structure shown in FIG. There is a possibility that each of the side walls 2a, 2a may interfere with components provided around the adjusting screw 10, such as spherical bearings, which constitute the engine. For this reason, depending on the structure of the engine, it may not be possible to adopt it.

On the other hand, if the bending direction of the side walls formed at both ends in the width direction of the connecting plate is reversed to the structure shown in FIGS. Although interference with components can be prevented, simply reversing the bending direction of the side wall portion causes a new problem as follows. That is, after the adjusting screw 10 is screwed into the screw hole 9c and the axial position of the adjusting screw 10 is appropriately adjusted, a part of the adjusting screw 10 protruding from the connecting plate portion to the opposite side to the valve from the connecting plate portion. , Lock nut 18
(See FIG. 20). In the case where a structure in which the bending direction of the side wall portion is simply reversed is adopted as described above, a tool such as a wrench used when tightening the lock nut 18 interferes with the leading edge of the side wall portion. This tightening operation becomes impossible or difficult.
In view of such circumstances, the sheet metal rocker arm of the present invention is intended to reduce the manufacturing cost of the sheet metal rocker arm as well as to improve the rigidity of the mounting portion of the adjusting screw as in the case of the previous invention. It was done.

[0022]

A rocker arm made of sheet metal according to the present invention is manufactured by pressing a single metal plate, and the movement of a cam is moved to a valve with a swing displacement about a fulcrum. To communicate. Such a rocker arm made of sheet metal according to the present invention comprises a connecting plate portion and a pair of substantially parallel side wall portions provided by bending both widthwise ends of the connecting plate portion in the same direction. An auxiliary plate portion is provided in such a manner that one end in the length direction of the connecting plate portion is folded back to the same side as each of the side wall portions so as to be superimposed on the connecting portion in the thickness direction. Then, screw holes concentric with each other are formed at positions where the auxiliary plate portion and the connection plate portion are aligned with each other, and one end in the length direction of each side wall portion is connected to the connection plate with respect to the center of the screw hole. The part is located up to one end in the length direction. Further, one side of the auxiliary plate portion located on the opposite side to the connection plate portion is recessed toward the connection plate portion side from the edge of the portion of each of the side wall portions located on both sides of the auxiliary plate portion. Not. In other words, of the side wall portions, the edges of the portions located on both sides of the auxiliary plate portion are located on the same plane as one surface of the auxiliary plate portion located on the opposite side to the connection plate portion, Alternatively, it is located closer to the connection plate portion than this one side.

[0023]

According to the rocker arm made of sheet metal of the present invention having the above-described structure, the thickness of the metal plate constituting the rocker arm and the diameter of the screw hole are the same as those of the rocker arm made of sheet metal according to the above-mentioned invention. Regardless, the length of the screw hole and the thickness of the metal part existing on the outer diameter side of the screw hole can be ensured. Therefore, it is possible to reduce the weight of the sheet metal rocker arm and to improve the strength of the screwing portion between the screw hole and the adjusting screw. In addition, since it is not necessary to weld or braze different parts, cost can be reduced by simplifying the manufacturing process and product inspection.

Further, according to the rocker arm made of sheet metal of the present invention, the adjusting screw can be used without interfering with other components incorporated in the engine or complicating the tightening operation of the lock nut screwed into the adjusting screw. It is possible to improve the rigidity of the connecting plate portion having the screw hole formed by screwing the connecting plate.
That is, since a pair of side walls provided at both ends in the width direction of the connecting plate portion extend to the side of the screw hole, a portion of the connecting plate portion where the screw hole is formed is formed. The section modulus is increased, so that the connecting plate portion can be effectively prevented from being deformed irrespective of a large thrust load or moment load applied from the adjusting screw. Also, each of the side wall portions is
Since it is bent to the same side as the auxiliary plate portion, interference between each of these side wall portions and the components provided around the adjusting screw among the components of the engine hardly occurs. Further, since the edge of each side wall does not protrude from one side of the auxiliary plate located on the opposite side to the connecting plate, the lock nut in which each side wall is screwed with the adjusting screw is used. There is no hindrance to tightening.

[0025]

1 and 2 show a first embodiment of the present invention. This example shows a case where the present invention is applied to the first example of the structure according to the preceding invention shown in FIGS. The feature of the present invention is to prevent interference with other components of the engine and to prevent troublesome tightening work of the lock nut 18 screwed to the adjusting screw 10,
Is to improve the rigidity of the portion where the screw hole 9c for screwing is formed. The structure and operation of the other parts are the same as those of the second example of the conventional structure shown in FIGS. 15 and 16 or the first example of the structure according to the preceding invention, and the same parts are the same. The reference numerals are used to omit or simplify the duplicate description, and the following description will focus on features of the present invention.

In the case of the rocker arm 14c made of sheet metal of this embodiment, both ends in the width direction (upper and lower ends in FIG. 2) of the connecting plate portion 19b are connected to the opposite side (upper side in FIG. 1) of the valve 11 (see FIG. 12). 2 is formed to form a pair of side walls 2b, 2b substantially parallel to each other. An auxiliary plate portion 20 formed by folding one end (the left end portion in FIGS. 1 and 2) in the length direction of the connection plate portion 19b to the opposite side to the valve 11 similarly to the side wall portions 2b and 2b.
Is disposed between the pair of side wall portions 2b, 2b. In this way, the auxiliary plate portion 20 is connected to the pair of side wall portions 2b,
The width of the auxiliary plate portion 20 is smaller than the distance between the pair of side wall portions 2b, 2b so that the work of disposing the auxiliary plate portion between the pair of side walls 2b can be easily performed.

The concentric screw holes 9c are formed at positions where the auxiliary plate portion 20 and the connecting plate portion 19b are aligned with each other. Also, a part of each of the side wall portions 2b, 2b is located on both sides of the screw hole 9c. That is,
The position of the longitudinal end edge of each of the side walls 2b, 2b indicated by α in FIG. 2 (the left end in FIGS. 1 and 2) is the center of the screw hole 9c indicated by β in FIG. It is located closer to one end (the left end in FIGS. 1 and 2) in the length direction of the connecting plate portion 19b than the position.

Further, one surface 23 of the auxiliary plate portion 20, which is located on the opposite side to the connecting plate portion 19b and is a contact surface of the lock nut 18, is provided between the side wall portions 2b and 2b. Edges 24, 2 of portions located on both sides of plate portion 20
4 is not recessed toward the connection plate portion 19b. In other words, of the side wall portions 2b, 2b, the edges 24, 24 of the portions located on both sides of the auxiliary plate portion 20 are connected to the one side of the auxiliary plate portion 20 located on the opposite side to the connection plate portion 19b. It is located on the same plane as 23 or on the side of the connecting plate portion 19b (the lower side in FIG. 1) with respect to this one side 23. For this reason, in the case of this example, each of the side wall portions 2
b, of the part at a portion located on either side of the auxiliary plate section 20 of the 2b the height h _2, the thickness T ₂₀ of the auxiliary plate section 20 below (h
₂ ≤ T ₂₀ ).

According to the rocker arm 14c made of sheet metal of the present invention having the above-described structure, the rocker arm 14c interferes with other components of the engine such as a spherical bearing, or the adjust screw 10
The rigidity of the connecting plate portion 19b formed with the screw hole 9c into which the adjusting screw 10 is screwed can be improved without complicating the tightening operation of the lock nut 18 screwed into the screw hole. That is, the pair of side walls 2b and 2b provided at both ends in the width direction of the connecting plate 19b extend to the side of the screw hole 9c. The section modulus of the portion where the hole 9c is formed becomes large, so that the connecting plate portion 19b can be effectively prevented from being deformed irrespective of the large thrust load and moment load applied from the adjusting screw 10. In addition, each of the side walls 2b, 2b
Is bent to the opposite side to the valve 11 (see FIG. 12) and the spherical support (not shown), like the auxiliary plate portion 20, so that each of these side wall portions 2b, 2b and the engine components Therefore, the components around the adjusting screw 10 do not easily interfere with each other. Further, the edge 24, 24 of each of the side wall portions 2b, 2b is located on the opposite side to the connecting plate portion 19b and serves as a contact surface of the lock nut 18 than the one surface 23 of the auxiliary plate portion 20. Since there is no protrusion, the side walls 2b, 2b do not hinder the tightening of the lock nut 18 screwed to the adjusting screw 10. That is, when the lock nut 18 is tightened, a part of a tool such as a spanner or a box wrench interferes with a part of each of the side walls 2b, 2b, and the work of tightening the lock nut 18 becomes impossible or troublesome. Nothing.

FIG. 3 shows a second embodiment of the present invention.
An example is shown. Rocker arm 14d made of sheet metal of this example
Is obtained by applying the present invention to the second example of the structure according to the preceding invention shown in FIGS. In this case,
The connecting plate 19b and the auxiliary plate 20 are separated from each other,
The height H ₂ of the side wall portion 2b provided at the portion where the screw hole 9c is formed on both sides in the width direction of the connecting plate portion 20 is determined by the amount of the gap 25 interposed between the two plate portions 19b and 20. Greater than the height h ₂ in the case of the first example (H ₂ > h ₂ )
are doing. However, the fact that the edge 24 of each of the side walls 2b, 2b does not protrude beyond the one surface 23 of the auxiliary plate 20 is as follows.
This is the same as the case of the first example described above.

As described above, the sheet metal rocker arm 14 of the present embodiment is used.
In the case of d, the height H ₂ of the side walls 2b, 2b is equal to the distance between the connection plate 19b and the auxiliary plate 20.
Can be increased. For this reason, the second structure of the structure according to the prior invention
In addition to the operation and effect obtained by the example, the operation and effect that the rigidity and strength of the connecting plate portion 19b in the sheet metal rocker arm 14d can be further improved can be obtained. The structure and operation of the other parts are the same as in the case of the first example described above.

In each of the first and second examples of the embodiment of the present invention described above, the base end surface of the valve 11 (see FIG. 12) is formed on one surface (the lower surface in FIGS. 1 and 3) of the connecting plate portion 19a. The structure that does not have a structure for guiding the valve 11 in the width direction of the connecting plate portion 19a (the front and back directions in FIGS. 1 and 3) is shown at the portion where the connector 11 abuts. Since the structure of this portion is not related to the gist of the present invention, the structure is free. However, a concave groove-shaped engaging portion for guiding the valve 11 is formed on one surface of the connecting plate portion 19a. You can do things. When such an engaging portion is formed, by adopting a method as described in JP-A-2000-120411, both ends of the connecting plate portion 19a in the width direction are opposite to the valve 11. With such a structure, it is possible to obtain the above-described engaging portion.

Next, FIGS. 4 to 10 show a third embodiment of the present invention. In each of the above-described examples, the roller that engages with the cam is pivotally supported at an intermediate portion in the longitudinal direction of the sheet metal rocker arms 14c and 14d. A roller 7 is pivotally supported at a longitudinal end by a pivot 5. For this reason, in the case of the present example, both ends of the pivot 5 are fitted in circular holes 17 formed concentrically with each other at the longitudinal end of the rocker arm 14e made of sheet metal, and both ends of the pivot 5 are connected to each other. The pivot 5 is fixed to the end of the sheet metal rocker arm 14e by swaging. With both ends of the pivot 5 caulked and widened, the pair of side walls 2b, 2b provided at both ends in the width direction of the connecting plate 19 are in a state where elasticity in a direction approaching each other is applied. Therefore, there is no rattling of the fitting support of the pivot 5 with respect to these side walls 2b, 2b, and no creep occurs in the fitting support. The roller 7 is rotatably supported by a needle bearing 6 around the intermediate portion of the pivot 5 fixed to the end of the sheet metal rocker arm 14e. For this purpose, the pivot 5 is made of high carbon chromium bearing steel such as JIS SUJ2 and the like. . It should be noted that the pivot 5
Are fitted together by tight fit, this pivot 5
Creep can be prevented more reliably.

Further, a second pivot (not shown) for swingably supporting the sheet metal rocker arm 14e to the cylinder head of the engine is inserted through an intermediate portion in the longitudinal direction of the sheet metal rocker arm 14e. Second circular holes 26, 26
Are formed by burring. Therefore, a short cylindrical portion 27,
27 are formed. Rocker arm 14 made of sheet metal
In a state where e is assembled to the engine, the short cylindrical portions 27, 27 are supported around the second pivot by a sliding bearing or a needle bearing so as to be swingable. In addition, an auxiliary plate portion 20 and a screw hole 9c are provided at one end in the length direction of the sheet metal rocker arm 14e in the same structure as in the first example described above.

When manufacturing the rocker arm 14e made of sheet metal as described above, first, a blank 28 as shown in FIG. 7 is formed by punching with a press. This blank 28
During the punching process, the second circular holes 26, 26 are formed, but the circular holes 17 for supporting both ends of the pivot 5 are not yet formed. Next, the portion of the base plate 28 that should become the connecting plate portion 19, that is, the oblique lattice portion of FIG. 7 is suppressed, and the boundary between this portion and the other portion, that is, the chain line portion of FIG. Fold or fold in front of 7.
Then, an intermediate material 29 as shown in FIG. 8 is obtained. Then
The side wall portions 2b and 2b are formed concentrically with each other at the longitudinal end portion of the intermediate material 29 by cutting using a drilling machine or turning using a lathe. The above-mentioned rocker arm 14e made of sheet metal is used.
The opening of the circular hole 17 is chamfered to provide a receiving surface when both ends of the pivot 5 are swaged and widened.
Further, if necessary, the inner peripheral surfaces of the pair of short cylindrical portions 27, 27 are subjected to cutting using a drilling machine or turning using a lathe, so that the two short cylindrical portions 27, 27 are formed. 2
7 are strictly concentric with each other. Other configurations and operations are the same as those of the first example shown in FIGS. 1 and 2 described above, and thus redundant description will be omitted.

FIG. 11 shows a fourth embodiment of the present invention. In the case of this example, the auxiliary plate portion 20a itself has a two-layered structure, and the thickness of the portion where the screw hole 9c (see FIG. 1) is formed is equal to the thickness of the connecting plate portion 19, which is equivalent to three metal plates. And the thickness. Since the structure and operation of the other parts are the same as those of the first example or the third example, illustration and description of the equivalent parts are omitted.

[0037]

The rocker arm made of sheet metal of the present invention is constructed and operates as described above. Therefore, as with the rocker arm made of sheet metal according to the preceding invention, both weight reduction and durability are ensured. In addition, it can contribute to the improvement of the performance of an engine incorporating a sheet metal rocker arm with an adjusting screw.
In addition, since the manufacturing process and the inspection process are not complicated, the cost can be reduced. Further, in the case of the sheet metal rocker arm of the present invention, the adjusting screw can be screwed without interfering with other components incorporated in the engine or complicating the tightening operation of the lock nut screwed into the adjusting screw. It is possible to improve the rigidity of the connecting plate portion having the screw holes to be formed. Therefore, the degree of freedom in engine design can be improved, and the design of a high-performance engine can be facilitated.

[Brief description of the drawings]

FIG. 1 is a cut-away side view showing a first example of an embodiment of the present invention.

FIG. 2 is a view as seen from above in FIG. 1;

FIG. 3 is a sectional side view showing a second example of the embodiment of the present invention.

FIG. 4 is a perspective view showing a third example of the embodiment of the present invention in a state where rollers are assembled.

FIG. 5 is a side view of the same.

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a plan view of a base plate for manufacturing a third example rocker arm made of sheet metal.

FIG. 8 is a side view of an intermediate material formed by bending the raw plate.

FIG. 9 is a side view of a sheet metal rocker arm having a circular hole formed at an end of the intermediate material.

FIG. 10 is a view taken in the direction of arrow B in FIG. 9;

FIG. 11 is a partial side view showing a fourth example of the embodiment of the present invention and corresponding to a left end portion in FIG. 5;

FIG. 12 is a sectional side view showing a first example of a conventional structure.

FIG. 13 is a bottom view of the same.

FIG. 14 is an exploded view of the components.

FIG. 15 is a plan view showing a second example of the conventional structure.

FIG. 16 is a sectional view taken along line CC of FIG. 15;

FIG. 17 is a plan view showing a first example of the structure according to the prior invention.

FIG. 18 is a sectional view taken along line DD of FIG. 17;

FIG. 19 is a view similar to FIG. 18, showing a second example of the structure according to the prior invention;

FIG. 20 shows a state in which an adjusting screw is screwed, and FIG.
FIG.

FIG. 21 is a view similar to FIG. 19, showing a third example of the structure according to the prior invention;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Rocker arm 2, 2a, 2b Side wall part 3 Screw plate part 4 Valve engagement part 5 Axis 6 Needle bearing 7 Roller 8 Short cylindrical part 9, 9a, 9b, 9c Screw hole 10 Adjust screw 11 Valve 12 Valve spring 13 Cam 14 , 14a, 14b, 14c, 14d, 14e Rocker arm 15 made of sheet metal 15 Rocker arm body 16 Nut plate 17 Circular hole 18 Lock nut 19, 19a, 19b Connecting plate 20, 20a Auxiliary plate 21 Curved part 22 Bent part 23 One side 24 Edge 25 Gap 26 Second circular hole 27 Short cylindrical part 28 Base plate 29 Intermediate material

Claims (1)

[Claims] 1. A rocker arm made of sheet metal, which is manufactured by performing press working on a single metal plate, and transmits the movement of a cam to a valve with a swing displacement about a fulcrum,
A connecting plate portion, a pair of substantially parallel side wall portions provided by bending both ends in the width direction of the connecting plate portion in the same direction, and one longitudinal end portion of the connecting plate portion. By folding back to the same side as each of these side wall portions, an auxiliary plate portion is provided so as to be overlapped with respect to the connecting portion in the thickness direction, and the auxiliary plate portion and the connecting plate portion are aligned with each other. In addition, while forming screw holes concentric with each other, the longitudinal end of each of the side wall portions is positioned to a portion closer to the longitudinal end of the connecting plate portion than the center of the screw hole, and further, One side of the auxiliary plate portion located on the opposite side to the connection plate portion is not recessed toward the connection plate portion side than the edge of the portion of each of the side wall portions located on both sides of the auxiliary plate portion. Rocker arm made of sheet metal.