JP4039936B2 - Rocker arm - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rocker arm used for an internal combustion engine (engine).
[0002]
[Prior art]
When the rocker arm body is a cast product, a through-hole extending in the entire width direction is formed in the body, and a rocker shaft installed in the cylinder head is directly inserted into the through-hole.
[0003]
On the other hand, when the body of the rocker arm is made of sheet metal for the purpose of reducing the overall weight and cost, a coaxial through hole is formed on a pair of opposing side walls of the body, and this through hole Sleeves are erected on each of them, and a rocker shaft is inserted through the inner periphery of the sleeve (see Patent Document 1). The sleeve is fixed by stamping the both axial end surfaces of the sleeve while the sleeve is fitted in the through hole of the body.
[0004]
[Patent Document 1]
JP-A-2001-3713 [0005]
[Problems to be solved by the invention]
In the above conventional example, it is necessary to use a sleeve separate from the body of the rocker arm, and it is necessary to perform embossing when fixing the sleeve to the body. There is room for improvement here.
[0006]
[Means for Solving the Problems]
The rocker arm of the present invention is supported by a rocker shaft provided in the cylinder head, and is tilted with the rocker shaft as a fulcrum by a cam provided in the cylinder head to open and close a valve provided in the cylinder head. and a top fuselage made of sheet metal which is connected with the respective connecting wall in the end parts longitudinally adjacent direction intermediate a pair of opposing side walls substantially parallel. A substantially U-shaped recess is provided in the middle in the longitudinal direction of the both side walls so as to open upward, and in the middle region in the width direction of the fuselage between the both side walls , there is an upward An arch portion curved in a semi-cylindrical shape so as to protrude to the other end is provided in a state of being spanned from one end side to the other end side of the opening portion of each recess. By combining these recesses and arch portions, the inner diameter dimension is set slightly larger than the outer diameter dimension of the rocker shaft, and a hole-like space penetrating in the width direction of the fuselage rotates the rocker shaft. It is made as an insertion part for direct insertion freely. Protruding pieces projecting toward the other side are provided on the inner edges of the respective recesses.
[0007]
In this configuration, the insertion portion of the rocker shaft is formed by the two recesses provided on the pair of side walls and the arch portion, and the sleeve as in the conventional example is not used.
[0009]
In this configuration, the receiving surface of the rocker shaft is made as wide as possible by the projecting piece provided on the inner edge of the recess, so that the posture of the body is stabilized and the load resistance is improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 to 6 show an embodiment of the present invention. In this embodiment, a center pivot type rocker arm 1 is taken as an example. The rocker arm 1 is supported by a rocker shaft 2 provided in the cylinder head at a longitudinal intermediate portion thereof, and is tilted about the rocker shaft 2 as a fulcrum by a cam 3 provided in the cylinder head. 4 is opened and closed.
[0011]
The rocker arm 1 includes a sheet metal body 5, a valve adjustment screw 6, and a roller 7.
[0012]
The body 5 is formed by bending a single metal plate into a substantially inverted U-shaped cross section, thereby forming a pair of opposed strip-like side walls 15 and 16, a first connecting wall 17 connecting one end side in the longitudinal direction, and a longitudinal direction. A second connecting wall 18 that connects the other end portion in the middle is provided. On the other end side in the longitudinal direction of the pair of side walls 15, 16, coaxial through holes 19, 19 are provided. The first connecting wall 17 is provided with a cylindrical bulging portion 20, and the cylindrical bulging portion 20 is provided with a screw hole.
[0013]
The adjusting screw 6 is brought into contact with the stem end of the valve 4 and is screwed onto the cylindrical bulged portion 20 and is in contact with the valve 4 by changing the screwing amount. (Valve clearance) is adjusted. The adjusting screw 6 is positioned and fixed with respect to the body 5 by screwing and attaching a nut 8 to a portion of the adjusting screw 6 protruding from the upper end of the cylindrical bulging portion 20.
[0014]
The roller 7 is rotatably provided at the other longitudinal end of the pair of side walls 15 and 16 of the body 5, and the cam 3 is brought into contact with the roller 7. That is, the roller 7 is supported via the plurality of needle rollers 11 with respect to the support shaft 10 installed in the through holes 19 and 19 of the pair of side walls 15 and 16.
[0015]
In this embodiment, an insertion portion for directly inserting the rocker shaft 2 in a freely rotatable manner is provided in the middle of the body 5 in the longitudinal direction, and without using a sleeve as in the conventional example. The plurality of semi-cylindrical portions are combined and not formed as a through-hole formed by simply penetrating the side walls 15 and 16. The said insertion part is demonstrated in detail below.
[0016]
At the middle in the longitudinal direction of the pair of side walls 15 and 16 of the body 5, substantially U-shaped recesses 25 and 26 are provided so as to open upward as viewed from the side. Further, an arch portion 27 is bridged between the first side wall 15 and the other side wall 16 with respect to the first connecting wall 17 and the second connecting wall 18. The arch portion 27 is curved in a semi-cylindrical shape so as to protrude upward, and each other from one end side of the opening portion of the recesses 25 and 26 between the one side wall 15 and the other side wall 16. It is arranged in a region reaching the end side.
[0017]
By combining such two concave portions 25 and 26 and one arch portion 27, the hole-like space 28 penetrating in the width direction of the body 5 is inserted through the rocker shaft 2 so as to be freely rotatable. It is made as a part. The hole-like space 28 is substantially circular when viewed from the side, and the inner diameter dimension thereof is set slightly larger than the outer diameter dimension of the rocker shaft 2.
[0018]
In addition, a protruding piece 29 is provided on the inner edge of the recesses 25 and 26 so as to project inward in the width direction, and the surface width of the recesses 25 and 26 is larger than the thickness of the pair of side walls 15 and 16 by the protruding piece 29. Is also getting bigger. By providing the projecting pieces 29, the surface that receives the rocker shaft 2 is made as wide as possible, whereby the posture of the body 5 is stabilized and the load resistance is enhanced.
[0019]
Next, the manufacturing procedure of the body 5 will be briefly described.
[0020]
First, as shown in FIG. 5, a single metal plate (for example, JIS standard SCM415 or SPCC) is punched to obtain a blank material 5A having a predetermined shape. Burring is performed on a predetermined region of the blank material 5A to form a cylindrical bulge portion 20, and a thread is formed in an inner hole of the cylindrical bulge portion 20.
[0021]
Then, as shown in FIG. 6, the blank material 5 </ b> A is bent into an approximately inverted U shape, and then the band-shaped portion 5 </ b> B provided between the first connecting wall 17 and the second connecting wall 18 is bent upward. Thus, the semi-cylindrical arch portion 27 is obtained. Further, the surface of the recesses 25 and 26 of the pair of side walls 15 and 16 is crushed by the processing tool 30 and plastically processed so that the meat part is plastically flowed and protruded toward the inner edge side of the recesses 25 and 26, thereby A piece 29 is obtained. Further, centering is performed so that the centers of curvature of the two concave portions 25 and 26 coincide with the center of curvature of one arch portion 27. Thereby, the hole-shaped space 28 formed by combining the two concave portions 25 and 26 and the one arch portion 27 is a circular hole having a predetermined accuracy.
[0022]
Thereafter, through holes 19 and 19 are formed in the pair of side walls 15 and 16, and heat treatment (soft nitriding, carbonitriding, and carburizing) is performed on the body 5, and then the through holes 19 and 19 in the pair of side walls 15 and 16 are performed. On the other hand, a roller 7 is attached via a support shaft 10 and a needle roller 11. The heat treatment improves the seizure resistance and wear resistance of the two concave portions 25 and 26 and the one arch portion 27 that are in sliding contact with the rocker shaft 2, but at least the two concave portions 25 and 26 and one arch portion are improved. The surface of the portion 27 may be coated with a solid lubricant such as PTFE (polytetrafluoroethylene), or may be shot blasted or shot peened.
[0023]
As described above, since the sleeve of the conventional example is not used for the insertion part of the rocker shaft 2, the number of parts can be reduced and the mounting work can be simplified, and the productivity can be improved. It will be possible to contribute to the reduction of manufacturing costs.
[0024]
In addition, this invention is not limited only to embodiment mentioned above, Various application and deformation | transformation can be considered.
[0025]
(1) FIGS. 7 to 12 show other embodiments of the present invention. In this embodiment, a projecting piece 32 obtained by bending is provided with respect to the inner edges of the recesses 25 and 26. In this case, as shown in FIG. 11, at the stage of obtaining the blank 5A, a rectangular protruding piece 32 is provided on the bottom of the recesses 25 and 26, and the protruding piece 32 is added as shown in FIG. The tool 30 is used for bending. If it is such a protrusion 32, the surface which receives the rocker shaft 2 can be made still wider than the said embodiment.
[0026]
(2) Although not shown, the present invention can also be applied to an end pivot type rocker arm. Moreover, in the said embodiment, about structures other than the insertion part of the rocker shaft 2, it does not specifically limit. For example, although not shown, a configuration in which the adjusting screw 6 is not used in the contact portion with the valve 4 may be employed. Further, the roller 7 can be directly fitted to the support shaft 10 by a clearance fit without using the needle roller 11 or can be fitted via a slide bearing.
[0027]
【The invention's effect】
In the present invention, since the sleeve as in the conventional example is not used, it is possible to reduce the number of parts and simplify the mounting work, and to contribute to the improvement of productivity and the reduction of manufacturing cost.
[0028]
In addition, since the rocker shaft is received by the two concave portions provided on the pair of side walls and the load applied to the rocker shaft is made difficult to be applied to the arch portion, the rigidity of the trunk is secured, so the load resistance is improved. An excellent structure can be obtained.
[Brief description of the drawings]
1 is a side view showing a rocker arm according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the rocker arm of FIG. 1. FIG. 3 is a top view of the rocker arm of FIG. FIG. 5 is a plan view showing the shape of the blank material obtained in the manufacturing process of the rocker arm fuselage of FIG. 1. FIG. 6 is a view of forming protrusions in the recesses of the rocker arm fuselage of FIG. 4 is a side view showing a rocker arm according to another embodiment of the present invention. FIG. 8 is an exploded perspective view of the rocker arm in FIG. 7. FIG. 9 is a top view of the rocker arm in FIG. 10 is a cross-sectional view taken along line (9)-(9) in FIG. 7. FIG. 11 is a plan view showing the shape of a blank material obtained in the manufacturing process of the rocker arm body in FIG. 7. FIG. A figure corresponding to FIG.
DESCRIPTION OF SYMBOLS 1 Rocker arm 2 Rocker shaft 3 Cam 4 Valve 5 Body 6 Valve adjustment screw 7 Roller 10 Support shafts 15, 16 A pair of side walls 17 of the body First connection wall 18 of the body Second connection walls 25, 26 of the body Side wall recess 27 Arch Part 28 hole-like space

Claims (1)

A rocker arm that is supported by a rocker shaft provided in the cylinder head and that is tilted about the rocker shaft by a cam provided in the cylinder head to open and close a valve provided in the cylinder head;
A body made of a sheet metal in which upper portions of both side portions adjacent to each other in the longitudinal direction of a pair of side walls opposed in parallel are connected by connecting walls, respectively .
A substantially U-shaped recess is provided in the middle in the longitudinal direction of the both side walls so as to open upward, and in the middle region in the width direction of the fuselage between the both side walls , between the two connecting walls, An arch portion curved in a semi-cylindrical shape so as to protrude is provided in a state of being spanned from one end side to the other end side of the opening portion of each recess,
By combining these recesses and arch portions, the inner diameter dimension is set slightly larger than the outer diameter dimension of the rocker shaft, and a hole-like space that penetrates in the width direction of the fuselage rotates the rocker shaft. It is made as an insertion part for direct insertion freely ,
A rocker arm , wherein an inner edge of each recess is provided with a projecting piece projecting toward the other side .

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