JP6712937B2 - Cylinder head valve mechanism - Google Patents

Description

The technique disclosed by the present specification relates to a valve operating mechanism of a cylinder head.

BACKGROUND ART Conventionally, as a valve operating mechanism of a cylinder head that opens and closes a valve by a rocker arm, for example, one described in Japanese Patent Application Laid-Open No. 2007-177708 (the following Patent Document 1) is known. This valve operating mechanism is an end pivot type, and includes a rocker arm, a cam disposed above a roller provided in the central portion of the rocker arm, and the like, and the valve can be opened and closed by rocking the rocker arm. An adjust screw is positioned and fixed by a nut at one end of the rocker arm. This adjusting screw has a hemispherical convex curved portion, and this convex curved portion is fitted to the concave curved surface of the pivot receiver.

JP 2007-177708 A

However, when the above valve operating mechanism is applied to a slant engine, the convex portion of the adjust screw is temporarily separated from the concave curved surface of the pivot receiver in the cam base section due to the relationship between the valve layout and gravity, and the next cam lift section is At that time, the convex curved portion of the adjusting screw collides with the concave curved surface of the pivot receiver. Therefore, an impact load is applied to both the adjusting screw and the pivot receiver, which may damage the adjusting screw.

A valve operating mechanism of a cylinder head disclosed by the present specification is a screw having a roller arm having a roller in a central portion and a spherical portion provided at an end portion of a shaft portion, wherein the roller arm is provided at one end portion of the roller arm. A screw having a fixed shaft portion, a valve that comes into contact with the other end of the roller arm, a cam that swings the other end of the roller arm by contacting the roller, and a receiving portion that receives the spherical portion. Having a pivot, a mounting recess provided in the cylinder head, in which the pivot is mounted, and a holding portion that holds the spherical portion so as not to separate from the receiving portion, and is mounted in the mounting recess together with the pivot. And a clip.

According to such a configuration, the rotation of the cam causes the rotation of the roller, and the other end of the roller arm swings about the screw fixed to the one end of the roller arm. Here, in the conventional valve mechanism, the spherical portion of the screw may be separated from the receiving portion of the pivot during the cam base section, but in the above valve operating mechanism, the spherical portion of the screw causes the spherical portion of the screw to be received by the holding portion of the clip. Since they are held so as not to separate from each other, the spherical portion does not collide with the receiving portion during the next cam lift section. Therefore, damage to the screw can be avoided by reducing the impact load applied to both the screw and the pivot.

The valve operating mechanism of the cylinder head disclosed in this specification may have the following configuration.
The clip has a protrusion that protrudes laterally beyond a side surface of the pivot before the pivot is mounted in the mounting recess, and the holding portion that is disposed closer to the pivot than the protrusion. However, when the pivot is mounted in the mounting recess, the protrusion may interfere with the inner wall of the mounting recess so that the holder contacts the spherical portion.
According to this structure, the holding portion can be brought into contact with the spherical portion by mounting the pivot in the mounting recess. In other words, before the pivot is mounted in the mounting recess, the holding portion is located away from the spherical portion, so that the screw can be easily mounted on the pivot.

The inner wall of the mounting recess may be provided with a drop-out preventing groove that prevents the pivot from falling out of the mounting recess by accommodating the protrusion.
With this configuration, the clip is prevented from falling out of the mounting recess by accommodating the protrusion in the drop-out prevention groove, and the pivot is prevented from falling out of the mounting recess by contact of the holding portion with the spherical portion. it can.

The clip has a pair of the holding portions arranged to face each other, and the spherical portion is provided between the pair of holding portions before the pivot is mounted in the mounting recess. An assembling opening for assembling into the receiving portion is provided, and the opening diameter of the assembling opening may be smaller than the maximum diameter of the spherical portion.
According to this structure, when the clip is attached to the pivot and the spherical portion of the screw is attached to the pivot receiving portion from the assembling opening provided between the pair of holding portions, the opening diameter of the assembling opening is increased. Is smaller than the maximum diameter of the spherical portion, it is possible to temporarily hold the spherical portion in the receiving portion by the pair of holding portions.

A clip mounting groove for mounting the clip is provided on an outer surface of the pivot, the clip has a protrusion, and the protrusion is press-fitted and fixed to a bottom wall of the clip mounting groove. The fixing hole may be provided.
With such a configuration, the clip can be fixed to the clip mounting groove by mounting the clip in the clip mounting groove of the pivot and press-fitting the protrusion into the fixing hole.

According to the technique disclosed in the present specification, it is possible to avoid damage to the screw by reducing the impact load applied to both the screw and the pivot.

Sectional drawing which showed the valve operating mechanism of the cylinder head in Embodiment 1. A perspective view showing a state before assembling the screw, the pivot, and the clip. Sectional view showing a state in which the pivot is being mounted in the mounting recess. Sectional view showing a state in which the pivot is mounted in the mounting recess. Sectional drawing which showed the pair of protrusion part of the clip in Embodiment 2 accommodated in the pair of fall-prevention groove|channels of a mounting recessed part.

<Embodiment 1>
Embodiment 1 will be described with reference to the drawings of FIGS. 1 to 4. As shown in FIG. 1, the valve operating mechanism 10 of the cylinder head 1 according to the first embodiment includes a roller arm 20, a screw 30, a valve 40, a cam 50, a pivot 60, and a clip 70. ing.

The roller arm 20 is configured to extend from the end of the valve 40 toward the pivot 60, and the roller 21 is rotatably provided at the center in the extending direction. The cam 50 is in contact with the roller 21, the rotation of the cam 50 causes the roller 21 to rotate, and the other end 24 swings around the spherical portion 33 of the screw 30 fixed to the roller arm 20 as a fulcrum. 40 is designed to move in the axial direction.

A fixing hole 23, into which the shaft portion 31 of the screw 30 is fixed, is provided through one end portion 22 of the roller arm 20. The screw 30 is fixed by a nut 32 with the shaft portion 31 positioned in the fixing hole 23. A spherical portion 33 is provided on the opposite side of the screw 30 from the nut 32. The spherical portion 33 has a spherical shape and is provided at the end of the shaft portion 31.

The other end 24 of the roller arm 20 has a substantially arc shape, and the outer peripheral surface side of the other end 24 is in contact with the outer surface of the valve cap 41. The valve cap 41 has a cap shape, and the inner surface of the valve cap 41 is in contact with the end portion of the valve stem 42 that constitutes the valve 40. A spring receiver 43 is fixed to the end of the valve stem 42. The end of the valve spring 44 is always in contact with the spring receiver 43.

The cam 50 has an oval shape as a whole and is connected to the cam shaft 53, and includes a cam base 51 and a cam lobe 52. The cam base 51 has an arcuate shape arranged coaxially with the cam shaft 53, while the cam lobe 52 is continuous with the cam base 51 and protrudes radially outward from the cam base 51.

The cam 50 rotates with the rotation of the cam shaft 53, and the roller 21 rotates with the rotation of the cam 50. In the cam base section where the cam base 51 contacts the roller 21, the other end 24 of the roller arm 20 does not swing and is maintained at a constant height, but in the cam lift section where the cam lobe 52 contacts the roller 21, the roller arm 20 The other end 24 swings to contract the valve spring 44, and the valve 40 is pushed toward the combustion chamber.

As shown in FIG. 2, the pivot 60 has a substantially columnar shape, and a hemispherical receiving portion 62 for receiving the spherical portion 33 of the screw 30 is recessed at one end 61 in the axial direction of the pivot 60. .. A clip mounting groove 64 is provided in a range from both side surfaces of the pivot 60 to the other end 63. The clip mounting groove 64 has a generally gate shape as a whole, and a pair of notches 65 that are inclined inward in the radial direction are provided at both ends on the receiving portion 62 side. A fixing hole 66 is provided in the bottom wall of the clip mounting groove 64 at the other end 63 of the pivot 60. The fixing hole 66 has a shape that axially penetrates between the receiving portion 62 and the other end portion 63.

The clip 70 is formed by pressing a metal plate, and as shown in FIG. 2, a clip body 71 having a substantially gate shape and opening upward, and a pair of clip bodies 71 provided at both ends of the clip body 71. And a holding portion 72. The pair of holding portions 72 have a substantially L shape, and are oriented inward in a mutually opposing arrangement. A right-angled portion of the holding portion 72 that projects laterally is a projection 73. Further, the columnar portion projecting upward from the bottom surface of the clip body 71 is a protrusion 74.

When the clip 70 is mounted on the pivot 60, as shown in FIG. 3, the clip main body 71 is housed in the clip mounting groove 64, and the projection 74 is press-fitted into the fixing hole 66 to fix the clip 70 to the pivot 60. On the other hand, the pair of holding portions 72 is in a state of protruding from the clip mounting groove 64. An assembly opening 75 is provided between the tips 72A of the pair of holding portions 72. The opening diameter D1 of the assembling opening 75 is smaller than the maximum diameter D2 of the spherical portion 33.

When the spherical portion 33 of the screw 30 is attached to the receiving portion 62 of the pivot 60, the spherical portion 33 passes through the assembly opening 75 while bending the pair of holding portions 72 outward. Then, after the spherical portion 33 has passed through the assembling opening 75, the pair of holding portions 72 elastically return to return to their original postures. Therefore, the screw 30 and the pivot 60 are temporarily held by the pair of holding portions 72, and the screw 30, the pivot 60, and the clip 70 can be integrally handled in a state where they are preassembled.

As shown in FIGS. 3 and 4, when the screw 30, the pivot 60, and the clip 70 are integrated and pushed into the mounting recess 2 provided in the cylinder head 1 in the direction of the arrow in FIG. The interference of 73 with the inner wall of the mounting recess 2 causes the pair of holding portions 72 to be displaced toward each other and contact the spherical portion 33. Since the pair of holding portions 72 are in contact with the spherical portion 33 from the side opposite to the receiving portion 62, the spherical portion 33 can be held so as not to separate from the receiving portion 62. Therefore, it is possible to prevent the clearance from being formed between the spherical portion 33 and the receiving portion 62 regardless of the relationship between the valve layout and the gravity in the slant engine. The pair of holding portions 72 are housed in the clip mounting groove 64 and the pair of notches 65, and the portions protruding from the pair of notches 65 contact the spherical portion 33.

As described above, in the present embodiment, the rotation of the cam 50 causes the roller 21 to rotate, and the other end 24 swings with the screw 30 fixed to the one end 22 of the roller arm 20 as a fulcrum. Here, in the conventional valve operating mechanism, the spherical portion of the screw may be separated from the receiving portion of the pivot in the cam base section, but in the above valve operating mechanism, the spherical portion 33 of the screw 30 is moved by the holding portion 72 of the clip 70. Since the pivot 60 is held so as not to separate from the receiving portion 62 of the pivot 60, the spherical portion 33 does not collide with the receiving portion 62 in the next cam lift section. Therefore, it is possible to avoid damage to the screw 30 by reducing the impact load applied to both the screw 30 and the pivot 60.

The clip 70 has a protruding portion 73 that protrudes laterally beyond the side surface of the pivot 60 before the pivot 60 is mounted in the mounting recess 2, and a holding portion 72 that is disposed closer to the pivot 60 than the protruding portion 73. Alternatively, the holding portion 72 may be in contact with the spherical portion 33 by the protrusion 73 interfering with the inner wall of the mounting recess 2 when the pivot 60 is mounted in the mounting recess 2.
With such a configuration, the holding portion 72 can be brought into contact with the spherical portion 33 by mounting the pivot 60 in the mounting recess 2. In other words, since the holding portion 72 is located away from the spherical portion 33 before the pivot 60 is attached to the attachment recess 2, the screw 30 can be easily attached to the pivot 60.

The clip 70 has a pair of holding portions 72 arranged so as to face each other, and the spherical portion 33 is received between the pair of holding portions 72 before the pivot 60 is mounted in the mounting recess 2. An assembling opening 75 for assembling to the portion 62 is provided, and the opening diameter D1 of the assembling opening 75 may be smaller than the maximum diameter D2 of the spherical portion 33.
According to this structure, when the clip 70 is attached to the pivot 60 and the spherical portion 33 of the screw 30 is attached to the receiving portion 62 of the pivot 60 through the assembling opening 75 provided between the pair of holding portions 72. Since the opening diameter D1 of the assembling opening 75 is smaller than the maximum diameter D2 of the spherical portion 33, the spherical portion 33 can be temporarily held in the receiving portion 62 by the pair of holding portions 72.

A clip mounting groove 64 for mounting the clip 70 is provided on the outer surface of the pivot 60, the clip 70 has a protrusion 74, and the protrusion 74 is provided on the bottom wall of the clip mounting groove 64. A configuration may be adopted in which a fixing hole 66 that is press-fitted and fixed is provided.
With this configuration, the clip 70 can be fixed to the clip mounting groove 64 by mounting the clip 70 in the clip mounting groove 64 of the pivot 60 and press-fitting the protrusion 74 into the fixing hole 66.

<Embodiment 2>
Next, a second embodiment will be described with reference to the drawing of FIG. The valve mechanism 11 in the second embodiment is obtained by partially modifying the configuration of the mounting recess 2 of the first embodiment, and the other configurations are the same. The inner wall of the mounting recess 3 in the present embodiment is provided with a drop-out preventing groove 4 that prevents the pivot 60 from falling out of the mounting recess 3 by accommodating the protrusion 73. The holding portions 72 of the clip 70 tend to move in the directions in which they are separated from each other due to the spring elasticity thereof, so that the protruding portions 73 are fitted in the drop-prevention grooves 4 and are accommodated therein.

Since the projecting portion 73 is hooked and locked to the opening of the drop-out preventing groove 4, the clip 70 can be prevented from dropping out of the mounting recess 3. Further, since the pair of holding portions 72 holds the spherical portion 33 on the receiving portion 62, the movement of the receiving portion 62 is prevented via the spherical portion 33. Further, the movement of the receiving portion 62 is prevented, so that the pivot 60 is held in the mounting recess 3.

As described above, in the present embodiment, the clip 70 is prevented from dropping from the mounting recess 3 by accommodating the protruding portion 73 in the drop-preventing groove 4, and the holding portion 72 contacts the spherical portion 33, so that the pivot 60 is released. Can be prevented from falling off from the mounting recess 3.

<Other Embodiments>
The technology disclosed in the present specification is not limited to the embodiments described by the above description and the drawings, and includes various aspects such as the following.
(1) The valve operating mechanisms 10 and 11 can be applied to both the intake side and the exhaust side.

(2) In the above embodiment, the clip 70 having the pair of holding portions 72 is illustrated, but the shape and number of the holding portions are not limited, and one holding portion can hold the spherical portion 33. You may make it a holding part.

(3) In the above embodiment, the clip 60 is elastically deformed by mounting the pivot 60 in the mounting recesses 2 and 3, and the pair of holding portions 72 come into contact with the spherical portion 33. The pair of holding portions may be in contact with the spherical portion 33 before being attached to the second and third portions.

(4) In the above embodiment, the projection 70 is press-fitted into the fixing hole 66 to fix the clip 70 to the pivot 60. However, instead of the projection 74, the clip is screwed into the fixing hole to pivot the clip. It may be fixed to 60. Alternatively, the clip body 71 may be fixed to the pivot 60 by elastically sandwiching the pivot 60 from the left and right sides instead of the protruding portion 74.

DESCRIPTION OF SYMBOLS 1... Cylinder head 2, 3... Mounting recessed part 4... Fall-out prevention groove 10, 11... Valve mechanism 20... Roller arm 21... Roller 22... One end part 24... Other end part 30... Screw 31... Shaft part 33... Spherical part 40 ... Valve 50... Cam 60... Pivot 62... Receiving part 64... Clip mounting groove 66... Fixing hole 70... Clip 72... Holding part 73... Projection part 74... Projection part 75... Assembly opening D1... Assembly opening Aperture diameter D2... Maximum diameter of spherical part

Claims (5)

A roller arm having a roller in the center,
A screw in which a spherical portion is provided at an end portion of a shaft portion, wherein the shaft portion is fixed to one end portion of the roller arm,
A valve that contacts the other end of the roller arm,
A cam that swings the other end of the roller arm by contacting the roller;
A pivot having a receiving portion for receiving the spherical portion,
A mounting recess provided on the cylinder head, in which the pivot is mounted,
A valve operating mechanism for a cylinder head, comprising: a holding portion for holding the spherical portion so as not to separate from the receiving portion, and a clip mounted in the mounting recess together with the pivot. The clip has a protrusion that protrudes laterally beyond a side surface of the pivot before the pivot is mounted in the mounting recess, and the holding portion that is disposed closer to the pivot than the protrusion. And
The valve operating mechanism of the cylinder head according to claim 1, wherein when the pivot is mounted in the mounting recess, the protrusion contacts the inner wall of the mounting recess so that the holding portion contacts the spherical portion. The valve operating mechanism for the cylinder head according to claim 2, wherein a drop-prevention groove is provided on an inner wall of the mounting recess to prevent the pivot from falling out of the mounting recess by accommodating the protrusion. The clip has a pair of the holding portions arranged to face each other, and the spherical portion is provided between the pair of holding portions before the pivot is mounted in the mounting recess. The assembling opening for assembling to the receiving portion is provided, and the opening diameter of the assembling opening is smaller than the maximum diameter of the spherical portion. Cylinder head valve mechanism. A clip mounting groove for mounting the clip is provided on an outer surface of the pivot, the clip has a protrusion, and the protrusion is press-fitted and fixed to a bottom wall of the clip mounting groove. A valve operating mechanism for a cylinder head according to any one of claims 1 to 4, wherein a fixing hole is provided.

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