JP2019052560A - Vehicular valve cam - Google Patents

Abstract

To provide a vehicular valve cam capable of preventing the occurrence of problems due to wear, while ensuring the operation responsivity of an intake/exhaust valve.SOLUTION: A vehicular valve cam 10 for driving an intake/exhaust valve 3 of a vehicle, is equipped with a base portion 11 which rotates about an axis with rotations of a cam shaft 9; a cam nose 12 formed so as to project outward in a diametrical direction from the base portion 11; and a roller portion 13 which has a rotary shaft 13a inserted in a through hole formed on the cam nose 12 and capable of rotating about an axis, a first roller 13b provided on one end side of the rotary shaft 13a, and a second roller 13c provided on the other end side on the opposite side to the one end side of the rotary shaft 13a. The first roller 13b and the second roller 13c abut on the intake/exhaust valve 3 side.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle valve cam.

  A valve cam 100 for a vehicle is employed in the valve mechanism 1 illustrated in FIG. 1 of the drawings of the present application, and has a function of driving an intake / exhaust valve 3 provided in an intake / exhaust port 2 of a vehicle engine. . As shown in FIGS. 6 and 7, a roller type valve cam 100 used conventionally has a base portion 101 that rotates about the axis along with the rotation of the camshaft 9, and protrudes radially outward from the base portion 101. A cam nose 102 formed in the cam nose 102, a through hole formed in the cam nose 102, a rotating shaft 103a that is supported by the cam nose 102 and rotatable about the axis, and the rotating shaft 103a. And a roller portion 103 having a roller 103b. As shown in FIG. 7, the roller 103b is in contact with the intake / exhaust valve side (the tappet 8).

  In the valve cam 100 shown in FIGS. 6 and 7, the base portion 101 rotates around the axis as the cam shaft 9 rotates (see arrow r4 in FIG. 7), and the roller 103b rotates around the axis along with this rotation. However, it abuts on the intake / exhaust valve side (the tappet 8) (see arrow r5 in FIG. 7). For this reason, compared with the valve cam which is not provided with the roller part 103, the frictional force between the valve cam 100 and the intake / exhaust valve side (tapet 8) can be reduced.

On the other hand, since both ends of the roller 103b is supported by a structure in the cam nose 102, toward the camshaft width _{W 21} of the roller 103b than the camshaft width _{W 2} of the base portion 101 is inevitably small. For this reason, compared with the valve cam which is not provided with the roller part 103, the surface pressure which acts on the intake / exhaust valve side (tapet 8) becomes large. In addition, when the lubrication is insufficient or the roller 103b is stuck, the roller 103b having a small cam axial width comes into sliding contact with the intake / exhaust valve side (the tappet 8), which is more than a valve cam that does not include the roller portion 103. There was a risk of wear.

  Therefore, for example, in the valve operating apparatus shown in Patent Document 1, the valve lifter side that reciprocates together with the valve has a pair of rollers extending outward in the axial direction of the valve. The occurrence of defects is reduced (see paragraph 0015 of FIG. 1 and FIG. 1).

Japanese Patent Laid-Open No. 10-61415

  In the valve operating device according to Patent Document 1, since a pair of rollers are provided on the intake and exhaust valve side that reciprocates at high speed, the weight of the intake and exhaust valve increases, and the followability of the valve to the operation of the cam decreases. There is a risk of doing.

  Accordingly, an object of the present invention is to prevent the occurrence of problems due to wear while ensuring the operation responsiveness of the intake and exhaust valves.

  In order to solve the above problems, according to the present invention, in a vehicle valve cam for driving an intake / exhaust valve of a vehicle, a base portion that rotates about an axis along with the rotation of the cam shaft, and radially outward from the base portion A protruding cam nose, a rotating shaft that is inserted through a through-hole formed in the cam nose and is rotatable about an axis, a first roller provided on one end side of the rotating shaft, and the rotating shaft A roller portion having a second roller provided on the other end side opposite to the one end side, wherein the first roller and the second roller abut on the intake / exhaust valve side. A vehicle valve cam was constructed.

  In the above configuration, it is preferable that the sum of the widths in the cam shaft direction of the first roller and the second roller is greater than or equal to the width in the cam shaft direction of the base portion.

  In each said structure, it can be set as the structure from which the frictional force between said 1st roller and valve | bulb side member differs from the frictional force between said 2nd roller and said valve | bulb side member.

  In this configuration, the first roller and the second roller can be configured to be relatively unrotatable around the axis.

  In the configuration in which the frictional force is different, the difference in the frictional force is caused by a difference in friction coefficient between the first roller and the valve side member and between the second roller and the valve side member. Or a difference in frictional force due to a difference in camshaft width between the first roller and the second roller.

  As described above, instead of making the first roller and the second roller relatively unrotatable around the axis, the first roller and the second roller are relatively rotatable around the axis. A configuration in which the first roller and the second roller are rotated relative to each other in accordance with a difference between a frictional force between the roller and the valve-side member and a frictional force between the second roller and the valve-side member. It can also be.

  In this invention, the structure which provided the roller part which has a pair of roller in the both ends of the rotating shaft was employ | adopted for the cam nose of the valve cam for vehicles. In this way, the friction between the pair of rollers and the valve side member can be reduced without increasing the weight of the intake / exhaust valve, and the malfunction caused by wear while ensuring the operation responsiveness of the intake / exhaust valve. Can be prevented.

Sectional drawing which shows the valve mechanism which employ | adopted the valve cam for vehicles which concerns on this invention The perspective view which shows an example of the valve cam for vehicles employ | adopted as the valve mechanism shown in FIG. FIG. 2 is an exploded perspective view showing an example of a roller portion of the vehicle valve cam shown in FIG. The arrow view seen from the A direction in FIG. 1 which shows contact | abutting with the valve cam for vehicles shown in FIG. 2, and a tappet The disassembled perspective view which shows the other example of the roller part of the valve cam for vehicles shown in FIG. A perspective view showing a conventional example of a valve cam The arrow view seen from the A direction in FIG. 1 which shows contact | abutting with the valve cam and tappet shown in FIG.

  FIG. 1 shows a valve mechanism 1 employing a vehicle valve cam 10 (hereinafter abbreviated as a valve cam 10) according to the present invention. The valve mechanism 1 is provided in an intake / exhaust port 2 of a vehicle engine, and a valve cam 10 drives an intake / exhaust valve 3.

  The valve 3 has a shape in which a valve stem 3b is extended from a valve head 3a. And this valve stem 3b is penetrated by the valve guide 5 provided in the cylinder head 4, and is guided to the axial direction. A valve spring 6, a spring seat 7, and a tappet 8 are provided on the upper end side of the valve stem 3b. The valve 3 is urged toward the valve cam 10 by a valve spring 6.

  The lower end side of the valve spring 6 is fixed to the cylinder head 4 side, and the upper end side is fixed to the spring seat 7 side. That is, when the valve spring 6 expands and contracts, a force for rotating the valve 3 and the tappet 8 provided on the valve 3 around the axis acts on the cylinder head 4. By this rotation, the abutment portion between the tappet 8 and each of the rollers 13b and 13c, which will be described later, of the valve cam 10 always changes, and uneven wear of the tappet 8 is prevented.

  As shown in FIG. 2, the valve cam 10 includes a base portion 11, a cam nose 12, and a roller portion 13 as main components.

The base portion 11 is provided on a camshaft 9 that rotates by receiving the rotational force of the crankshaft of the engine, and rotates around the axis together with the camshaft 9. Camshaft width of the base portion 11 is W _1.

  The cam nose 12 is formed integrally with the base portion 11 so as to protrude radially outward from the base portion 11. The cam nose 12 has a distal end in the radial direction that is a thin portion 14 that is thinner in the cam shaft direction than the base portion 11, and a through hole (not shown) is formed in the thin portion 14.

  The roller portion 13 includes a rotating shaft 13a inserted through a through hole formed in the cam nose 12, a first roller 13b provided on one end side of the rotating shaft 13a, and a side opposite to the one end side of the rotating shaft 13a. The second roller 13c is provided on the other end side of the. As shown in FIG. 3, the rotating shaft 13a and the first roller 13b are integrated in advance, and the rotating shaft 13a is inserted into the through hole in this integrated state. Then, the second roller 13 c is press-fitted into the other end side of the rotating shaft 13 a so that the roller portion 13 can rotate with respect to the cam nose 12. By this press-fitting, the first roller 13b and the second roller 13c cannot be rotated relative to each other around the axis.

  By interposing a bearing between the inner surface of the through hole and the rotating shaft 13a, the rotational resistance of the roller portion 13 can be further reduced. Further, when the roller portion 13 is attached to the cam nose 12, a spacer is provided between each of the rollers 13b and 13c and the thin portion 14 of the cam nose 12, thereby preventing the rollers 13b and 13c and the cam nose 12 from coming into direct contact with each other. Thus, the rotational resistance of the roller portion 13 can be further reduced.

A camshaft width _{W 11} of the first roller 13b camshaft width _{W 12} of the second roller 13c is substantially the same. Further, the sum of the camshaft width _{W 11} of the first roller 13b camshaft width _{W 12} of the second roller _{13c S (W 11 + W 12} ) is greater than the camshaft width _{W 1} of the base portion 11 ( _{W 11 + W 12> W 1} ). In this case, the first roller 13b and the second roller 13c are insufficiently lubricated and the rollers 13b and 13c are fixed, and the rollers 13b and 13c are in sliding contact with the intake / exhaust valve side (the tappet 8). Even in this case, a predetermined contact width can be secured, and wear of the valve mechanism (particularly the upper surface of the tappet 8) can be prevented as much as possible.

This sum S is preferably at least as large as the cam shaft width W ₁ of the base portion 11 (W ₁₁ + W ₁₂ = W ₁ ). This is because the wear preventing action of the valve mechanism can be exhibited.

  Different materials are employed for the surface of the first roller 13b and the surface of the second roller 13c, and the friction coefficients (static friction coefficient, dynamic friction coefficient) between the surfaces and the tappet 8 are different. Therefore, as shown in FIG. 4, when the valve cam 10 is rotated around the axis with both the rollers 13 b and 13 c in contact with the tappet 8, the difference in frictional force between the rollers 13 b and 13 c and the tappet 8. Due to this, a rotational force for rotating the tappet 8 around the axis is generated.

  For example, in the configuration of FIG. 1, when the valve cam 10 rotates in the direction of the arrow r1 in FIG. 1 (FIG. 4), the rollers 13b and 13c contacting the tappet 8 are moved in the directions of r2 and r3 in FIG. Each rotates at the same rotation speed. When the tappet 8 (valve 3) rotates in the direction of arrow R1 in FIG. 4 when the valve 3 is pushed by the valve cam 10, the friction coefficient between the first roller 13b and the tappet 8 is set to the second roller 13c. It is preferable that the coefficient of friction with the tappet 8 is larger.

  In this way, when the valve 3 is pushed by both the rollers 13b and 13c, it is caused by the difference in frictional force between the first roller 13b having a relatively large frictional force and the second roller 13c having a relatively small frictional force. Thus, a rotational force that rotates the tappet 8 (valve 3) in the direction of the arrow R1 in FIG. 4 is generated, and the valve 3 can be pushed in smoothly. Further, by rotating the tappet 8, the oil around the tappet 8 can be caught between the tappet 8 and the sliding surface of the tappet guide, and the lubricating effect by the oil can be enhanced.

  When the valve 3 returns, the tappet 8 (valve 3) rotates in the direction of the arrow R2 in FIG. 4, and the rotation direction of the first roller 13b and the tappet 8 (valve 3) having a relatively large frictional force is Although the directions are relatively opposite, the surface pressure between the two is lower than that at the time of pushing in, so there is a problem in the rotation of the valve 3 due to the friction between the two. Absent.

Alternatively, while employing the same material on the first roller 13b and the second roller 13c, a cam shaft width W ₁₃ of the first roller 13b, by varying the camshaft width W ₁₄ of the second roller 13c, The frictional force between the rollers 13b and 13c and the tappet 8 may be varied.

If the materials and surface states of the rollers 13b and 13c are the same, the frictional force increases as the contact area between the rollers 13b and 13c and the tappet 8 increases. Therefore, as shown in FIG. 5, the cam shaft width _{W 13} of the first roller 13b, when larger than the camshaft width _{W 14} of the second roller 13c, the rollers 13b, at the time of pushing the valve 3 by 13c, A relatively large frictional force acts on the first roller 13b side rather than the second roller 13c side, and the tappet 8 (valve 3) is moved in the direction of the arrow R1 in FIG. 4 in the same manner as shown in FIG. Can be rotated.

  Similarly to the above, when the valve 3 is returned, the tappet 8 (valve 3) rotates in the direction of the arrow R2 in FIG. 4, and the first roller 13b and the tappet 8 (valve 3) having a relatively large frictional force. ) In the opposite direction, but at the time of return, the surface pressure between the two is lower than that at the time of pushing, so the friction between the two causes rotation of the valve 3. There is no problem.

In the above, each of the rollers 13b, by varying the coefficient of friction between 13c and the tappet 8, or by varying the respective rollers 13b, cam shaft width of 13c _{W 13, W 14,} each roller it is configured to vary the frictional force acting, the rollers 13b, the friction coefficient and the camshaft width W ₁₃ of _13c, W ₁₄ may be both made different. Or you may vary the frictional force which acts on each roller 13b and 13c by structure other than this.

  In the above description, the configuration in which the first roller 13b and the second roller 13c are relatively unrotatable around the axis has been described. For example, a bearing is interposed between the rotation shaft 13a and the second roller 13c, The roller 13b and the second roller 13c may be configured to be relatively rotatable around the axis.

  In this way, when the valve 3 rotates around the axis in accordance with the reciprocating motion, the rollers 13b and 13c contacting the valve 3 (the tappet 8) freely rotate around the axis, respectively. The frictional force between 13b and 13c and the valve 3 (the tappet 8) can be minimized. This may further prevent the valve mechanism from being worn.

  The valve cam 10 described above is merely an example for explaining the present invention, and it is an object of the present invention to prevent the occurrence of problems due to wear while ensuring the operation responsiveness of the intake / exhaust valve 3. As long as the above can be solved, the shape of the component can be appropriately changed. In addition, said valve cam 10 can be applied to all reciprocating engines, such as a gasoline engine and a diesel engine, and its versatility is high. Moreover, it can be easily applied not only to a new engine but also to an existing valve mechanism.

DESCRIPTION OF SYMBOLS 1 Valve mechanism 2 Intake / exhaust port 3 Valve 3a Valve head 3b Valve stem 4 Cylinder head 5 Valve guide 6 Valve spring 7 Spring seat 8 Tappet 9 Camshaft 10 Vehicle valve cam (valve cam)
11 Base part 12 Cam nose 13 Roller part 13a Rotating shaft 13b First roller 13c Second roller 14 Thin part

Claims (7)

In a vehicle valve cam that drives a vehicle intake and exhaust valve,
A base that rotates about the axis as the camshaft rotates,
A cam nose formed to protrude radially outward from the base portion;
A rotating shaft that is inserted into a through-hole formed in the cam nose and can rotate about the axis, a first roller provided on one end side of the rotating shaft, and other side opposite to the one end side of the rotating shaft A roller portion having a second roller provided on the end side;
And the first roller and the second roller are in contact with the intake / exhaust valve side. 2. The vehicular valve cam according to claim 1, wherein a sum of cam shaft direction widths of the first roller and the second roller is equal to or greater than a cam shaft direction width of the base portion. The vehicle according to claim 1, wherein a frictional force between the first roller and the valve side member is different from a frictional force between the second roller and the valve side member. Valve cam for use. 4. The vehicle valve cam according to claim 3, wherein the first roller and the second roller are not rotatable relative to each other around an axis. The difference in the frictional force is caused by a difference in friction coefficient between the first roller and the valve-side member, and between the second roller and the valve-side member. Or the valve cam for vehicles of 4. The vehicular valve cam according to any one of claims 3 to 5, wherein the difference in the frictional force is caused by a difference in cam shaft width between the first roller and the second roller. . The first roller and the second roller are rotatable relative to each other around an axis, and the frictional force between the first roller and the valve side member and between the second roller and the valve side member are 3. The vehicle valve cam according to claim 1, wherein the first roller and the second roller are rotated relative to each other in accordance with a difference from a frictional force.

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