JP3362136B2 - Rocker arm - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm for opening and closing a valve provided on a cylinder head in response to a sliding operation by a cam, and more particularly to a rocker arm for both roller supporting walls. The present invention relates to an improvement that prevents rotation of a shaft. 2. Description of the Related Art As a conventional rocker arm, for example, FIG.
Or as shown in FIG. In the figure, 1 is a cam portion of a cam shaft, 2 is a valve stem portion, 3 is a pivot portion of a lash adjuster, and 4 is a rocker arm. The rocker arm 4 has a structure in which a roller 6 is rotatably mounted on a rocker arm body 5. The rocker arm body 5 is manufactured by forming a metal plate into a substantially gate-shaped sheet metal. The rocker arm main body 5 includes two pairs of roller support walls 7 and 8 which are substantially parallel to each other, and both roller support walls 7 and 8. And a connecting portion 10 having a rectangular through hole 9 in the middle in the longitudinal direction. One end in the longitudinal direction of the connecting portion 10 is a valve engaging portion 11, and a pivot engaging portion 12 having a substantially hemispherical shape is formed on the other end in the longitudinal direction of the connecting portion 10. The cam portion 1 is in contact with the roller 6 protruding from the through hole 9 of the rocker arm body 5, the valve stem portion 2 is in contact with the valve engaging portion 11, and the lash adjuster is in contact with the pivot engaging portion 12. The pivot part 3 is engaged. A pair of roller support walls 7, 8 of the rocker arm body 5 are formed with shaft insertion holes 14, 14, respectively.
In a state where both ends of the shaft 3 are fitted, the shaft 13 is fixed by caulking both ends of the shaft insertion holes 14, 14 of the roller support walls 7, 8 at the outer opening edges. This swaging is performed by punching circular teeth 21 of a swaging jig 20 as shown in FIG.
Are plastically deformed, and are raised on a tapered chamfer 15 formed on the outer opening edges of the shaft insertion holes 14, 14. The shaft 1 fixed to the roller support walls 7 and 8 in this manner
A roller 6 is rotatably fitted at the axial center of the roller 3. The reference numeral 16 in FIG. 8 indicates a swaging mark. [0006] In the above-mentioned conventional example, if a portion of the shaft 13 that has been plastically deformed by caulking is slightly dislodged due to vibrations during use, the shafts of the roller support wall portions 7 and 8 will not move. The shaft 13 is rotatable in the insertion holes 14, 14 following the rotation of the roller 6. Thus, the shaft 13
When the shaft is rotated, the shaft insertion holes 14 and 14 are worn out and greatly expanded.
It will get out of 4,14. The shaft insertion holes 1 in the roller support walls 7, 8
It is considered that the shaft 13 can be simply prevented from rotating if the shaft 13 is directly press-fitted into the shafts 4 and 14. However, since the outer peripheral surface of the shaft 13 is damaged at the time of press-fitting, fixing by press-fitting is not performed at all. The present invention has been made in view of such circumstances, and has as its object to stably prevent rotation of a shaft without using a rotation preventing member. According to the present invention, there is provided a rocker arm body having a pair of roller support walls provided on both sides of a connecting portion so as to be substantially parallel to each other, and provided on each of the roller support walls. A rocker arm having a shaft whose both ends are fitted and then caulked and fixed at both ends in a shaft insertion hole, and a roller rotatably fitted at an intermediate position in the axial direction of the shaft has the following configuration. [0010] In the first rocker arm of the present invention, the entire periphery of the outer opening edge of the shaft insertion hole is chamfered, and the surface width of a part of the circumference of the chamfer is set to a dimension different from other portions. ing. [0011] In the second rocker arm of the present invention, the outer opening edge of the shaft insertion hole is partially chamfered. When the shaft is caulked and fixed in the shaft insertion hole of the roller support wall, the plastically deformed portions at both ends of the shaft are attached to the chamfered portion of the shaft insertion hole. Here, in the case of the first rocker arm, the amount by which the plastically deformed portion of the shaft rises to the chamfered portion becomes non-uniform in the circumferential direction of the shaft insertion hole. In other words, this means that the protruding length in the radial direction of the plastically deformed portion of the shaft is not uniform around the circumference of the shaft, and when the shaft is about to rotate,
The plastically deformed portion protruding in the radial direction is caught in the circumferential direction by a part of the chamfered portion of the shaft insertion hole, so that rotation of the shaft is prevented. Further, in the case of the second rocker arm, the plastically deformed portion of the shaft does not adhere to the portion of the shaft insertion hole where there is no chamfer. The shaft is hindered from being caught in the circumferential direction on the portion without the chamfer. FIG. 1 to FIG. 3 show an embodiment of the present invention. In this embodiment, the same components and parts as those shown in FIGS. 5 to 8 of the conventional example are denoted by the same reference numerals. In the figure,
1 is a cam portion of a cam shaft, 2 is a valve stem portion, 3 is a pivot portion of a lash adjuster, and 4 is a rocker arm. The rocker arm 4 has a structure in which a roller 6 is rotatably mounted on a rocker arm main body 5, and its basic structure is almost the same as that of the conventional example. Rocker arm body 5
Is manufactured by forming a metal plate into a substantially U-shaped sheet metal, and connects the pair of roller support walls 7 and 8 facing each other substantially parallel to each other, and connects the two roller support walls 7 and 8 together. A connecting portion 10 having a rectangular through hole 9 in the middle in the longitudinal direction.
And One end in the longitudinal direction of the connecting portion 10 is a valve engaging portion 11, and a pivot engaging portion 12 having a substantially hemispherical shape is formed on the other end in the longitudinal direction of the connecting portion 10. The cam portion 1 contacts the roller 6 protruding from the through hole 9 of the rocker arm body 5, the valve stem portion 2 contacts the valve engaging portion 11, and the pivot engaging portion 12
Is engaged with the pivot portion 3 of the lash adjuster. The pair of roller support walls 7 and 8 of the rocker arm body 5 are formed with shaft insertion holes 14 and 14, respectively.
In a state where both ends of the shaft 3 are fitted, the shaft 13 is fixed by caulking both ends of the shaft insertion holes 14, 14 of the roller support walls 7, 8 at the outer opening edges. The roller 6 is rotatably fitted to the shaft 13 at the center in the axial direction. The feature of the present embodiment lies in the chamfered shape of the shaft insertion holes 14, 14. That is, the outer opening edges of the shaft insertion holes 14 and 14 are continuously tapered in the circumferential direction.
In this chamfer 15, two chamfer widths facing each other by 180 degrees on the circumference are set to be larger than those of the other portions. Note that the chamfer width may be set smaller than other portions. In addition, shaft insertion hole 1
If the shafts 4 and 14 are not circular but irregular, even if the opening edges of the shaft insertion holes 14 and 14 are chamfered with a uniform width,
A detent effect can be obtained. If the chamfer width of the chamfer 15 is made non-uniform in the circumferential direction, when the both end surfaces of the shaft 13 are punched by using a caulking jig 20 having circular teeth 21 as shown in FIG. The plastically deformed portions 17 at both end edges of the 13 come to fill the entire chamfer width at any position of the chamfer 15. In other words, two portions 180 degrees opposite each other in the plastically deformed portion 17 of the shaft 13 include the wide portion 1 of the chamfer 15.
Since the projection 17a having a shape corresponding to 5a is formed, the shaft 13 is prevented from rotating due to the engagement between the projection 17a and the wide portion 15a of the chamfer 15. In the above embodiment, the shaft insertion hole 1
If the shafts 4 and 14 are not circular but irregular, even if the opening edges of the shaft insertion holes 14 and 14 are chamfered with a uniform width,
A detent effect can be obtained. FIG. 4 shows another embodiment of the present invention.
In this embodiment, the shaft insertion holes 14,
In one of the lower opening edges 14a, the chamfering 15 is not performed in a predetermined angle range so that the chamfering 15
In a C-shape. If the chamfer 15 is discontinuous in the circumferential direction in this manner, plastic deformation due to caulking does not occur in a predetermined angle range without chamfering of the shaft 13, so that
Even if the shaft 13 tries to rotate in the shaft insertion holes 14, 14,
The rotation of the shaft 13 is prevented by the catch between the plastically deformed portion 17 of the shaft 13 and the non-chamfered portions of the shaft insertion holes 14, 14. In order to perform such caulking, a caulking jig 20a having C-shaped teeth 21a in the figure may be used. The present invention is not limited to only the above embodiment. For example, the overall shape of the rocker arm main body 5 is arbitrary, and a plurality of needle rollers may be interposed between the roller 6 and the shaft 13. The present invention also includes a case where the valve engaging portion 11 is formed separately from the rocker arm main body 5 and integrally connected thereto. Furthermore, the chamfer 15 does not have to be at one place on the circumference as shown in FIG. 4, and may be intermittently provided at several places in the circumferential direction. As described above, in the present invention, the shape of the plastically deformed portion due to the caulking of the shaft is controlled by devising the shape of the chamfer with respect to the outer opening edge of the shaft insertion hole. Of the shaft insertion hole in the circumferential direction. This makes it possible to reliably prevent the shaft from rotating without using the detent member and irrespective of the occurrence of temporal deformation of the plastically deformed portion due to caulking.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an embodiment of a rocker arm according to the present invention. FIG. 2 is an enlarged view of a caulking portion of a shaft in the embodiment. FIG. 3 is a caulking used for caulking in FIG. FIG. 4 is a view corresponding to FIG. 2 in another embodiment of the present invention. FIG. 5 is a side view showing a use state of a conventional sheet metal rocker arm. FIG. 6 is a rocker arm in FIG. FIG. 7 is a longitudinal sectional view of the rocker arm along the longitudinal direction. FIG. 8 is a longitudinal sectional view of the rocker arm along the width direction. 14 Shaft insertion hole in roller support wall 15 Chamfer of shaft insertion hole 16 Caulking mark 17 Shaft plastic deformation part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-321999 (JP, A) JP-A-2-94305 (JP, U) JP-A 64-34406 (JP, U) JP-A-3-34406 92509 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 1/18 F16H 25/00

Claims (1)

(1) A sheet metal rocker arm main body provided with a pair of roller support walls on both sides of a connecting portion so as to be substantially parallel to each other, respectively. A rocker arm having a roller support shaft having both ends fitted into a shaft insertion hole provided and then being caulked at both ends, and a roller rotatably fitted outside in the axial direction of the roller support shaft, The lower opening of the outer opening edges of the shaft insertion hole
A rocker arm, characterized in that other open edges other than a predetermined angle range of the edge are partially chamfered in advance .