JP2020118063A - Vehicle cam mechanism - Google Patents

Abstract

To provide a vehicle cam mechanism which secures a sufficient lubrication state between a roller shaft and a roller.SOLUTION: A vehicle cam mechanism includes: a cam shaft 10 formed with an oil supply hole 10a allowing communication between an interior and an exterior and having a hollow pipe shape; a cam lobe 11 which has a base part 11a and a cam nose 11b, includes a recessed cutout part 11c opening to a tip side and formed in the cam nose 11b, and rotates around its axis integrally with the cam shaft 10; a roller shaft 12 which is provided at the cam nose 11b so as to be parallel with the cam shaft 10 and cross the cutout part 11c, formed with an oil discharge hole 12a allowing communication between an interior and an exterior, and has a hollow pipe shape; and a roller 13 provided at the roller shaft 12. The cam lobe 11 is formed with an oil guide passage 11e which guides lubrication oil supplied from the oil supply hole 10a to a roller 13 side. The roller 13 has oil guide members 13a forming lubrication oil passages ranging from an outer periphery side to the roller shaft 12 and arranged in a rotation direction of the roller 13.SELECTED DRAWING: Figure 2

Description

This invention relates to a vehicle cam mechanism.

The vehicle cam mechanism is a mechanism for driving a valve for intake and exhaust provided in an intake and exhaust port of the engine. As this cam mechanism, for example, as shown in Patent Document 1, a roller type cam mechanism is provided in which a roller is provided at a cam nose of a cam lobe and the roller is brought into contact with a valve (tappet) to drive the valve. There is. With this configuration, the roller presses the valve (tappet) while rolling, so that the friction between the two can be reduced and the fuel consumption can be improved.

In this roller type cam mechanism, if lubrication between the roller shaft and the roller inserted into the roller shaft is insufficient, there is a possibility that problems such as galling, sticking, and abrasion may occur. Therefore, in the configuration according to Patent Document 1, the lubrication oil is supplied to the surface of the roller through the hollow cam shaft to solve the problem relating to lubrication (paragraphs 0032 to 0035 of Patent Document 1, FIG. 1). Etc.).

JP, 2014-190256, A

In the configuration according to Patent Document 1, as shown in FIGS. 5A and 5B, the lubricating oil supplied through the inside of the cam shaft 100 is applied to the surface of the roller 103 provided on the cam nose 102 of the cam lobe 101. Although the roller 103 is supplied, the roller 103 rotates by sliding with the tappet 104, and the cam lobe 101 itself also rotates around the axis of the cam shaft 100 (arrow r′ in FIG. 5A). , R'), and most of the lubricating oil supplied to the surface of the roller 103 is spilled out of the cam mechanism as it is due to the centrifugal force caused by the rotation (arrows in FIGS. 5A and 5B). f'). Therefore, it is difficult to supply the lubricating oil to the gap between the roller shaft 105 and the roller 103, and the lubrication tends to be insufficient.

Then, this invention makes it a subject to ensure a sufficient lubrication state between a roller shaft and a roller.

In order to solve the above problems, in the present invention, in a vehicle cam mechanism that drives an intake valve or an exhaust valve, a hollow tubular cam shaft having an oil supply hole communicating between the inside and the outside, a base portion and a cam nose are provided. The cam nose is formed with a concave cutout portion that opens toward the tip side thereof, and a cam lobe that rotates integrally with the camshaft around its axis, and the cutout portion in parallel with the camshaft. The cam lobe includes a hollow tubular roller shaft formed in the cam nose so as to straddle a portion, in which an oil drain hole communicating between the inside and the outside is formed, and a roller rotatably provided on the roller shaft. An oil guide path for guiding the lubricating oil supplied from the oil supply hole to the roller side is formed, and the roller forms a lubricating oil flow path from the outer peripheral side of the roller to the roller shaft, A cam mechanism for a vehicle having a plurality of oil guide members arranged in the rotation direction of the roller is configured.

In the above configuration, the plurality of oil guide members are inclined along the rotational direction from the outer peripheral side of the roller toward the rotation axis center in a side view from the axial direction of the roller. preferable.

In the above configuration, it is preferable that the wall thickness of the oil guide member in the rotation direction is relatively larger outside the roller than inside the roller.

In the above configuration, the plurality of oil guide members are inclined in the opposite direction to the rotation direction from the outer peripheral side of the roller toward the rotation axis center in a side view from the axial direction of the roller. You can also

In each of the above configurations, the oil guide path may extend along a rotation direction of the roller from a line connecting the axis of the cam shaft and the axis of the roller shaft in a side view from the axial direction of the cam lobe. It is preferably inclined.

In the configuration in which the oil guide passage is inclined, the size of the gap between the inner wall of the cutout portion on the base portion side and the outer periphery of the roller is such that the inclination direction of the oil guide passage is the inclination direction. It is preferably smaller than the opposite side.

According to the present invention, in a roller-type vehicle cam mechanism that supplies lubricating oil to a cam lobe via a camshaft, a plurality of oil guide members are provided on the roller, and the outer circumference of the roller is provided between adjacent oil guide members. The flow path of the lubricating oil from the side to the roller shaft is formed. With this configuration, the lubricating oil can be directly supplied between the roller shaft and the roller to ensure the sufficient lubricating state, and the roller can be smoothly rotated.

It is sectional drawing of the valve mechanism which employ|adopted the cam mechanism for vehicles which concerns on this invention. It is (a) sectional drawing and (b) side view of 1st embodiment of the cam mechanism for vehicles shown in FIG. FIG. 3 is a sectional view of a main part of the vehicle cam mechanism shown in FIG. 2. It is sectional drawing of 2nd embodiment of the cam mechanism for vehicles which concerns on this invention. It is (a) sectional drawing of the conventional vehicle cam mechanism, and (b) side view.

FIG. 1 shows a valve mechanism 2 that employs a vehicle cam mechanism 1 (hereinafter, simply referred to as a cam mechanism 1) according to a first embodiment of the present invention. This valve mechanism is provided in the intake/exhaust port 3 of the vehicle engine, and the cam mechanism 1 drives the intake/exhaust valve 4.

The valve stem 4a of the valve 4 is inserted into a valve guide 6 provided on the cylinder head 5 and guided in its axial direction. A valve spring 7, a spring seat 8 and a tappet 9 are provided on the upper end side of the valve stem 4a. The valve 4 is biased toward the cam mechanism 1 by the valve spring 7. The lower end side of the valve spring 7 is fixed to the cylinder head 5 side, and the upper end side thereof is fixed to the spring seat 8 side.

As shown in FIGS. 2A and 2B, the cam mechanism 1 has a cam shaft 10, a cam lobe 11, a roller shaft 12, and a roller 13 as main constituent elements.

The camshaft 10 is a hollow tubular member, and a slit-shaped oil supply hole 10a that communicates the inside and the outside of the camshaft 10 is formed in correspondence with the mounting position of the cam lobe 11. Lubricating oil is supplied to the inside of the camshaft 10 by the hydraulic pressure of an engine (not shown), and the lubricating oil is supplied to the cam lobe 11 attached to the camshaft 10 through the oil supply hole 10a. It

The cam lobe 11 has a base portion 11a having a constant outer diameter, and a cam nose 11b formed so as to project radially outward from the base portion 11a. A through hole is formed in the center of the base portion 11a, and the camshaft 10 is inserted into this through hole. The cam nose 11b is formed with a recessed notch 11c that opens toward the tip side thereof. Roller shaft support portions 11d having fitting holes into which the roller shaft 12 is fitted are formed at both ends of the cutout portion 11c in the axial direction of the cam lobe 11. The cam lobe 11 rotates integrally with the cam shaft 10 about its axis.

The cam lobe 11 is formed with an oil guide path 11e communicating with the oil supply hole 10a and guiding the lubricating oil supplied from the oil supply hole 10a to the roller 13 side. This oil guide path 11e is viewed from a side view of the cam lobe 11 in the axial direction, and from a line connecting the shaft center of the cam shaft 10 and the shaft center of the roller shaft 12, the rotation direction of the roller 13 (the arrow in FIG. 2A). (See r)). As shown in FIG. 3, the size of the gap between the inner wall of the cutout portion 11c on the base portion 11a side and the outer periphery of the roller 13 is determined by the inclination direction side of the oil guide passage 11e (see reference numeral g _{1 in} FIG. 3). ), it is relatively smaller than the opposite side (see reference numeral g _{2 in} FIG. 3) of the tilt direction (g ₁ <g ₂ ).

The roller shaft 12 is fitted in a fitting hole formed in the roller shaft support portion 11d so as to be parallel to the cam shaft 10 and to straddle the cutout portion 11c. The roller shaft 12 is a hollow tubular member, and has a slit-shaped oil drain hole 12a that communicates the inside and the outside of the roller shaft 12. The oil drain hole 12a is inclined from the outer peripheral side of the roller shaft 12 toward the axial center thereof in the side view from the axial direction of the roller shaft 12 in the direction opposite to the rotation direction of the roller 13. .. The lubricating oil that has flowed into the roller shaft 12 from the oil drain hole 12 a is discharged to the outside of the cam mechanism 1 through the openings at both ends of the roller shaft 12. By increasing the slit width of the slit-shaped oil discharge hole 12a in the axial center portion of the roller shaft 12, the efficiency of inflow of the lubricating oil from the oil discharge hole 12a into the roller shaft 12 can be increased.

The roller 13 is rotatably provided on the roller shaft 12. The roller 13 is provided with a plurality of oil guide members 13a arranged along the entire circumference of the roller 13 in the rotation direction. Both axial ends of each oil guide member 13a are fixed to annular holding members 13b provided at both ends thereof. A flow path of lubricating oil from the outer peripheral side of the roller 13 to the roller shaft 12 is formed between the oil guide members 13a adjacent to each other in the rotation direction.

The oil guide member 13a is inclined along the rotation direction from the outer peripheral side of the roller 13 toward the rotation axis in a side view from the axial direction of the roller 13. That is, the inclination direction of the oil guide member 13a and the inclination direction of the oil drain hole 12a formed in the roller shaft 12 are opposite to each other. Further, the oil guide member 13a has a relatively large thickness t in the rotation direction on the outer side than on the inner side of the roller 13 (see FIG. 3), and its cross-sectional shape is a wing shape. Therefore, the width s in the rotation direction of the flow path of the lubricating oil formed between the oil guide members 13a adjacent to each other in the rotation direction is substantially constant from the outer peripheral side of the roller 13 to the rotation axis. (See Figure 3).

As described above, the oil guide member 13a is provided on the roller 13, and a hollow tubular member is adopted for the roller shaft 12 to form the oil drain hole 12a in the roller shaft 12, thereby forming a solid roller and a roller shaft. It is possible to reduce the weight of these members as compared with the case of adopting.

Next, the operation of the cam mechanism 1 will be described. Lubricating oil supplied from the oil supply hole 10a formed in the cam shaft 10 is injected toward the roller 13 through the oil guide passage 11e formed in the cam lobe 11 (arrow f ₁ in FIG. 2 (a) reference). The oil guide passage 11e is inclined along the rotation direction of the roller 13 from the line connecting the shaft center of the camshaft 10 and the shaft center of the roller shaft 12, so that the lubricating oil injected from the oil guide passage 11e Hits one side of the roller 13 (the right half side in FIG. 3). Then, the lubricating oil flows into a gap formed between the adjacent oil guide members 13a, 13a, and a rotational force is applied to the roller 13 by the supply pressure of the lubricating oil. Therefore, the roller 13 can be smoothly rotated as compared with the case where only the friction caused by the contact between the roller 13 and the tappet 9 is applied to the roller 13.

Moreover, the size of the gap between the outer periphery of the inner wall and the roller 13 of the cutout portion 11c, the inclination direction of the lubricant guide path 11e (reference numeral g ₁ in FIG. 3), the inclination direction of the opposite side ( Since it is made relatively smaller than the reference sign g _{2 in} FIG. 3), the flow velocity of the lubricating oil is increased when passing through the narrow gap, and the roller 13 can be rotated more smoothly.

Further, the width s of the flow path of the lubricating oil formed between the oil guide members 13a, 13a adjacent to each other in the rotation direction is set to be substantially constant from the outer peripheral side of the roller 13 to the rotation axis. A sufficient amount of lubricating oil necessary for lubricating the roller shaft 12 can be temporarily stored therein. Therefore, a sufficient lubrication state between the roller shaft 12 and the roller 13 can be ensured.

The lubricating oil in the flow path is carried to the tappet 9 side while lubricating the roller shaft 12 as the roller 13 rotates. Then, by the centrifugal force accompanying the rotation, a portion of the flow path in the reservoir was lubricating oil is blown out of the cam mechanism 1 toward the tappet 9 (see arrow f ₂ in FIG. 2 (a)), The gap between the tappet 9 and the roller 13 is lubricated. The lubricating oil that was not blown off by the centrifugal force remains in the flow path as it is. Then, the cam from the part of the lubricating oil flows from the oil discharge hole 12a formed in the roller shaft 12 to the roller shaft 12 (see arrow f ₃ in FIG. 2 (a)), both open ends of the roller shaft 12 is discharged out of the mechanism 1 (see arrow _{f 4} in Figure 2 (b)).

Further, in the side view from the axial direction of the roller shaft 12, the inclination direction of the oil guide member 13a and the inclination direction of the oil drain hole 12a formed in the roller shaft 12 are opposite to each other, so that the oil drain hole 12a is formed. It is possible to prevent the lubricating oil that has entered the roller shaft 12 from flowing back to the roller 13 side.

In this first embodiment, since the rotation direction of the roller 13 and the extending direction of the oil guide member 13a to the outer periphery form an obtuse angle, when the outer peripheral end of the oil guide member 13a and the tappet 9 slide. The outer peripheral end portion is in a state of being stroked on the surface of the tappet 9 and is unlikely to cause galling. Therefore, it is possible to prevent damage to the oil guide member 13a and damage to the tappet 9.

FIG. 4 shows a cam mechanism 1 according to the second embodiment of the present invention. The basic structure of the cam mechanism 1 according to the second embodiment is the same as that of the cam mechanism 1 according to the first embodiment, but the structures of the roller 13 and the roller shaft 12 are different from those according to the first embodiment. ..

That is, in the second embodiment, the plurality of oil guide members 13a provided on the roller 13 rotate in the side view from the axial direction of the roller 13 from the outer peripheral side of the roller 13 toward the rotation axis. It is inclined in the direction opposite to the direction (see arrow r in FIG. 4). The oil drain hole 12a formed in the roller shaft 12 extends in the rotational direction of the roller 13 from the outer peripheral side of the roller shaft 12 toward its axial center in a side view from the axial direction of the roller shaft 12. It is inclined to follow.

When the lubricating oil from the lubricant guide path 11e is ejected (refer to arrow f ₁ in FIG. 4), the rotational force is applied to the roller 13 by the supply pressure. Since the inclination direction of the oil guide member 13a is opposite to that in the first embodiment, this supply pressure has a small effect of causing the lubricating oil to enter the gap formed between the adjacent oil guide members 13a, 13a, but the injected lubrication Part of the oil is stored in the gap. Then, a part thereof is ejected to the outside of the cam mechanism 1 toward the tappet 9 (see arrow f _{2 in} FIG. 4), and the gap between the tappet 9 and the roller 13 is lubricated.

In this second embodiment, since the rotation direction of the roller 13 and the extending direction of the oil guide member 13a to the outer periphery form an acute angle, when the outer peripheral end of the oil guide member 13a and the tappet 9 slide. A part of the lubricating oil adhering to the surface of the tappet 9 can be scraped off and temporarily stored in the gap. Therefore, this lubricating oil can ensure a sufficient lubrication state between the roller shaft 12 and the roller 13.

Further, when the outer peripheral side end of the oil guide member 13a and the tappet 9 slide, foreign matter adhering to the surface of the tappet 9 can be scraped off and collected. This foreign matter is finally with lubricating oil flows to the oil discharge hole 12a (refer to arrow f ₃ in FIG. 4), is discharged from the opening ends of the roller shaft 12. Therefore, the surface of the tappet 9 can be kept clean.

The cam mechanism 1 described above is merely an example for explaining the present invention, and as long as it is possible to solve the problem of the present invention that secures a sufficient lubrication state between the roller shaft 12 and the roller 13. In the above, each component such as the shape of the oil guide member 13a, the inclination angle, the number of installations, the inclination angle of the oil guide passage 11e, and the like can be appropriately changed.

Further, the cam mechanism 1 described above can be applied to all reciprocating engines such as a gasoline engine and a diesel engine, and has high versatility. Further, not only a new engine but also an existing model can be widely applied by simply changing the shape of the cam lobe 11.

1 Vehicle cam mechanism (cam mechanism)
2 valve mechanism 3 intake/exhaust port 4 valve 5 cylinder head 6 valve guide 7 valve spring 8 spring seat 9 tappet 10 camshaft 10a oil supply hole 11 cam lobe 11a base 11b cam nose 11c notch 11d roller shaft support 11e oil guide 12 Roller shaft 12a Oil drain hole 13 Roller 13a Oil guide member 13b Holding member

Claims (6)

In a vehicle cam mechanism that drives an intake valve or an exhaust valve,
A hollow tubular camshaft in which an oil supply hole communicating between the inside and the outside is formed,
A cam lobe having a base portion and a cam nose, a concave cutout portion opening toward the tip side thereof is formed in the cam nose, and a cam lobe which rotates integrally with the cam shaft around the axis thereof;
A hollow tubular roller shaft provided in the cam nose in parallel with the cam shaft so as to straddle the notch, and in which an oil discharge hole communicating between the inside and the outside is formed,
A roller rotatably provided on the roller shaft,
Have
In the cam lobe, an oil guide path for guiding the lubricating oil supplied from the oil supply hole to the roller side is formed,
A cam mechanism for a vehicle, wherein the roller has a plurality of oil guide members that are arranged in a rotational direction of the roller and that form a flow path of lubricating oil from an outer peripheral side of the roller to the roller shaft. The vehicle according to claim 1, wherein the plurality of oil guide members are inclined along the rotational direction from the outer peripheral side of the roller toward the rotation axis center in a side view from the axial direction of the roller. Cam mechanism. The vehicle cam mechanism according to claim 2, wherein a wall thickness of the oil guide member in a rotation direction is relatively larger on an outer side than on an inner side of the roller. The plurality of oil guide members are inclined in a direction opposite to the rotation direction from the outer peripheral side of the roller toward the rotation axis center in a side view from the axial direction of the roller. Vehicle cam mechanism. The oil guide path is inclined along a rotational direction of the roller from a line connecting the axis of the cam shaft and the axis of the roller shaft in a side view from the axial direction of the cam lobe. The vehicle cam mechanism according to any one of 1 to 4. The size of the gap between the inner wall of the cutout portion on the base portion side and the outer periphery of the roller is relatively smaller on the inclination direction side of the oil guide passage than on the opposite side of the inclination direction. 5. The vehicle cam mechanism described in 5.

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