JP2016169667A - Position regulation mechanism of cam unit of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position regulation mechanism of a cam unit of an internal combustion engine which enables improvement of holding power when a position of the cam unit is regulated and inhibits resistance when the cam unit is moved.SOLUTION: A position regulation mechanism of a cam unit of an internal combustion engine includes: a cam shaft 110 including a hollow part 111 formed in an axial direction; a cam unit 120 which fits in the cam shaft 110 so as to slide in an axial direction and includes recessed parts 122 formed on a surface facing the cam shaft 110; a position regulation member 130 engaged with the recessed part 122; and a spring 140 which biases the position regulation member 130 to a side such that the position regulation member 130 engages with the recessed part 122. The position regulation member 130 includes: a hemispherical part 131 which engages with the recessed part 122; and a cylindrical part 132 which covers the spring 140. An engine oil which biases the position regulation member 130 to the side such that the position regulation member 130 engages with the recessed part 122 is supplied to the hollow part 111.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique of a position restriction mechanism for a cam unit of an internal combustion engine.

  The cam unit of the internal combustion engine has a plurality of cams corresponding to one cylinder of the internal combustion engine. For example, a multi-valve engine includes a plurality of intake valves and exhaust valves per cylinder, and a plurality of cams per cylinder.

  The cam unit position regulating mechanism is known as a mechanism for regulating the axial position of a cam unit that can slide in the axial direction with respect to the cam shaft in order to switch the valve operating characteristics of the intake and exhaust valves (for example, Patent Document 1). A conventional cam unit position restricting mechanism represented by Patent Document 1 will be described below as a position restricting mechanism 200.

The configuration of the position restriction mechanism 200 will be described with reference to FIG.
In addition, in FIG. 3, the structure of the position control mechanism 200 is typically represented by the side surface sectional view. Moreover, below, it demonstrates according to the axial direction or radial direction described in FIG.

  The position regulating mechanism 200 determines the position in the axial direction of the cam unit 220 slidable in the axial direction with respect to the camshaft 210 in order to switch the valve operating characteristics of an intake / exhaust valve of an engine (not shown) as an internal combustion engine. It is a mechanism to regulate.

  The position restriction mechanism 200 includes a cam shaft 210, a cam unit 220, position restriction members 230 and 230, and a spring 240.

  A hollow portion 211 is formed in the camshaft 210 along the axial direction. A through hole 212 is formed in the camshaft 210 along a radial direction at a predetermined position in the axial direction. The predetermined position is a position where the substantially central portion of the cam unit 220 faces when the cam unit 120 is provided on the camshaft 110 with its position regulated. The through hole 212 is formed in a direction orthogonal to the hollow portion 211 and communicates with the hollow portion 211.

  The cam unit 220 is a substantially cylindrical member in which a plurality of cams corresponding to one cylinder are formed on the outer peripheral surface. The cam unit 220 is formed with a through hole 221 through which the cam shaft 210 passes.

  The cam unit 220 is fitted to the camshaft 210 and is configured to be slidable in the axial direction with respect to the camshaft 210. The cam unit 220 is configured so as not to rotate relative to the circumferential direction of the cam shaft 210.

  Concave portions 222, 222 are formed in the axial direction on the inner peripheral surface of the through hole 221 of the cam unit 220 so as to be displaced from each other in the axial direction. The concave portions 222 and 222 are circumferential grooves formed along the circumferential direction on the inner peripheral surface of the through hole 221, and for example, the cross-sectional shape thereof is formed in a V shape. The recess 222 is formed so that a position restricting member 230 described later can be engaged therewith.

  The position restricting member 230 is a spherical member that engages with the recess 222 of the cam unit 120 and restricts the position of the cam unit 220 in the axial direction of the camshaft 110. That is, the position regulating member 230 is a member that positions the axial position of the cam unit 220.

  The position restricting member 230 is disposed on one end side and the other end side of the through hole 212 of the camshaft 210, and is configured to be slidable in the extending direction of the through hole 212. The position regulating member 230 is formed in a spherical shape having a diameter slightly smaller than the diameter of the through hole 212.

  The position restricting member 230 can be engaged with the recess 222 of the cam unit 220 while being fitted to the through hole 212 by sliding to the end side of the through hole 212 (outside in the radial direction of the camshaft 210). It has become.

  The position regulating members 230, 230 can regulate the position of the cam unit 220 in the axial direction of the camshaft 210 by engaging with the recess 222 of the cam unit 220. The cam unit 220 can be restricted to different axial positions when engaged with the other recess 222.

  That is, the cam unit 220 is restricted in its axial position at two restriction positions, one restriction position and the other restriction position on the camshaft 210.

  The spring 240 is disposed inside the position restricting members 230 and 230 in the through hole 212, and is on the side where the position restricting member 230 is engaged with the recess 222, that is, the end side of the through hole 212 (the diameter of the camshaft 210. It is biased toward the outer side.

The operation of the position regulating mechanism 200 will be described with reference to FIG.
In FIG. 4A, the state of the position restriction mechanism 200 at the time of position restriction is schematically shown in a side sectional view. FIG. 4B schematically shows the state of the position regulating mechanism 200 when it is moved in a side sectional view. Further, in the following, description will be given according to the axial direction or radial direction described in FIG.

  FIG. 4A shows a state in which the position of the cam unit 220 is restricted at one restriction position of the camshaft 210 in the position restriction mechanism 200. At this time, the position restricting member 230 is pressed outward in the radial direction by the urging force of the spring 240.

  The position restricting member 230 pressed outward in the radial direction is engaged with the recess 232 of the cam unit 220. The cam unit 220 in which the position restricting member 230 is engaged with the recess 232 is restricted in the axial position with respect to the cam shaft 210.

  In the position restriction mechanism 200, the cam unit 220 is configured to be movable from one restriction position to the other restriction position. FIG. 4B shows a state in which the cam unit 220 is moving from one restriction position of the camshaft 210 toward the other restriction position in the position restriction mechanism 200 (FIG. 4B). ) Direction of white arrow in the middle).

  At this time, the position restricting member 230 is located between the one concave portion 222 and the other concave portion 222 on the inner peripheral surface of the through hole 221, and is pressed by the inner peripheral surface of the through hole 221. It is in a state of sliding inward. When the position restricting member 230 is slid inside the through hole 212, the spring 240 is reduced as compared with a state where the position restricting member 230 is engaged with the recess 222.

  Accordingly, when the position restricting member 230 is positioned between the one recessed portion 222 and the other recessed portion 222, the pressing force on the inner peripheral surface of the through hole 221 by the position restricting member 230 is such that the position restricting member 230 is recessed. The pressing force applied to the concave portion 222 by the position restricting member 230 when engaged with 222 is larger.

  The pressing force applied to the cam unit 220 by the position restricting member 230, which increases during the movement of the cam unit 220 from one restricting position of the cam shaft 210 toward the other restricting position, is a resistance when the cam unit 220 moves. It becomes.

  Here, for example, when the engine is downsized, it is necessary to reduce the diameter of the camshaft 210. When the diameter of the camshaft 210 is reduced, the length of the through hole 212 that accommodates the spring 240 is shortened, so that the length of the spring 240 needs to be shortened.

  Further, in the position restriction mechanism 200, it is necessary to reduce the resistance when the cam unit 220 moves while ensuring the holding force of the cam unit 220 by the position restriction member 230.

  However, when the length of the spring 240 is shortened as the camshaft 210 is reduced in diameter as described above, it is possible to reduce the resistance when the cam unit 220 is moved while securing the holding force of the cam unit 220. It was difficult to construct a possible spring 240.

  In particular, when the cam unit 220 is moved, the position regulating member 230 slides inward of the through hole 212 and the spring 240 is contracted. It has been difficult to achieve both the securing of force and the suppression of resistance when the cam unit 220 moves.

Special table 2011-529552 gazette

  The problem to be solved by the present invention is to provide a position restriction mechanism for an internal combustion engine cam unit that can secure a holding force when the position of the cam unit is restricted and can suppress resistance when the cam unit is moved. It is.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a camshaft having a hollow portion formed in the axial direction and a cam shaft that is slidably fitted in the axial direction with respect to the camshaft, and a concave portion is formed on a surface facing the camshaft. A cam unit that is formed; a position restricting member that engages with the recess; and an elastic member that biases the position restricting member toward the side that engages the recess. A hemispherical portion that engages with the recess, and a cylindrical portion that covers the elastic member, and the hollow portion is supplied with a fluid that urges the position regulating member toward the side that engages with the recess. It is what is done.

  According to the position restriction mechanism for the cam unit of the internal combustion engine of the present invention, the holding force can be secured when the position of the cam unit is restricted, and the resistance can be suppressed when the cam unit is moved.

The schematic diagram which showed the structure of the position control mechanism. The schematic diagram which showed the effect | action of the position control mechanism. The schematic diagram which showed the structure of the conventional position control mechanism. The schematic diagram which showed the effect | action of the conventional position control mechanism.

The configuration of the position regulating mechanism 100 will be described with reference to FIG.
In FIG. 1, the configuration of the position regulating mechanism 100 is schematically shown in a side sectional view. Further, for easy understanding, the position restricting member 130 is schematically shown in perspective in the lower part of FIG. Further, in the following, description will be given according to the axial direction or radial direction described in FIG.

  The position restriction mechanism 100 is an embodiment according to the position restriction mechanism of the cam unit of the internal combustion engine of the present invention. The position regulating mechanism 100 determines the position in the axial direction of the cam unit 120 that is slidable in the axial direction with respect to the camshaft 110 in order to switch the valve operating characteristics of an intake / exhaust valve of an engine (not shown) as an internal combustion engine. It is a mechanism to regulate.

  The engine of the present embodiment is a multi-valve engine, and includes a plurality of intake valves and exhaust valves per cylinder, and a plurality of cams per cylinder.

  The position restriction mechanism 100 includes a camshaft 110, a cam unit 120, position restriction members 130 and 130, and a spring 140 as an elastic member.

  The camshaft 110 is rotatably supported by a cylinder head (not shown) via a bearing 150.

  A hollow portion 111 is formed in the camshaft 110 along the axial direction. Engine oil is supplied to the hollow portion 111 from an oil pump (not shown) via a crank journal (not shown). The discharge pressure of the oil pump is proportional to the engine speed. Therefore, the hydraulic pressure of the engine oil supplied to the hollow portion 111 is proportional to the engine speed.

  A through-hole 112 is formed in the camshaft 110 along a radial direction at a predetermined position in the axial direction. The predetermined position is a position where the substantially central portion of the cam unit 120 faces when the cam unit 120 is provided on the camshaft 110 with its position regulated.

  The through hole 112 is formed in a direction orthogonal to the hollow portion 111 and communicates with the hollow portion 111. Therefore, engine oil is supplied to the through hole 112.

  A through hole 113 is formed in the camshaft 110 along the radial direction at a position supported by the axial bearing 150. The through hole 113 is formed between the hollow portion 111 and the outer peripheral surface of the camshaft 110 and communicates with the hollow portion 111. Therefore, engine oil is supplied to the through hole 113.

  The cam unit 120 is a substantially cylindrical member in which a plurality of cams for opening and closing the intake and exhaust valves corresponding to one cylinder are formed on the outer peripheral surface. The cam unit 120 is formed with a through hole 121 through which the cam shaft 110 passes. The cam unit 120 is fitted to the camshaft 110 so as to be slidable in the axial direction.

  The inner peripheral surface of the through hole 121 is a surface facing the outer peripheral surface of the camshaft 110 in the cam unit 120. The cam unit 120 is configured so as not to rotate relative to the circumferential direction of the camshaft 110.

  Concave portions 122, 122 are formed in the axially substantially central portion of the inner peripheral surface of the through hole 121 of the cam unit 120 so as to be displaced from each other in the axial direction. The recesses 122, 122 are circumferential grooves formed along the circumferential direction on the inner peripheral surface of the through hole 121. For example, the cross-sectional shape thereof is formed in a V shape.

  The concave portion 122 is formed so that a hemispherical portion 131 of a position regulating member 130 described later can be engaged. In addition, although the two recessed parts 122 are formed in the cam unit 120 of this embodiment, it is not limited to this.

  The position regulating member 130 is a member that engages with the recess 122 of the cam unit 120 and regulates the position of the cam unit 120 in the axial direction of the cam shaft 110. That is, the position regulating member 130 is a member that positions the axial position of the cam unit 120.

  The position restricting member 130 is disposed on one end side and the other end side of the through hole 112 of the camshaft 110, and is configured to be slidable in the extending direction of the through hole 112. The position regulating member 130 includes a hemispherical part 131 and a cylindrical part 132.

  In the position restricting member 130 fitted in the through hole 112, the hemispherical part 131 is disposed on the end side of the through hole 112 (outside in the radial direction of the camshaft 110). The hemispherical portion 131 is arranged in a posture in which the hemispherical surface is directed toward the end portion side of the through hole 112 (outside in the radial direction of the camshaft 110), and is formed so as to be engageable with the concave portion 122. The hemispherical portion 131 is formed in a substantially hemispherical shape that is slightly smaller than the diameter of the through hole 112.

  In the position regulating member 130 fitted in the through hole 112, the cylindrical portion 132 is disposed inside the through hole 112 (in the radial direction of the camshaft 110) with respect to the hemispherical portion 131, and covers the spring 140. Is. The cylindrical portion 132 is formed in a cylindrical shape having an outer diameter slightly smaller than the diameter of the through hole 112.

  The length of the cylindrical portion 132 in the direction of the through hole 112 is such that the inner end of the cylindrical portion 132 is substantially at the same position as the inner peripheral surface of the hollow portion 111 of the camshaft 110 when the hemispherical portion 131 is engaged with the concave portion 122. It is formed to become. The cylindrical part 132 is formed integrally with the hemispherical part 131.

  The position restricting member 130 can be engaged with the recess 122 of the cam unit 120 while being fitted to the through hole 112 by sliding to the end side of the through hole 112 (the radially outer side of the camshaft 110). It has become.

  The position regulating members 130 and 130 can regulate the position of the cam unit 120 in the axial direction of the camshaft 110 by engaging with the concave portion 122 of the cam unit 120. The cam unit 120 can be restricted to different axial positions when engaged with the other recess 122.

  That is, the cam unit 120 is restricted in its axial position at two restriction positions, one restriction position and the other restriction position on the camshaft 110.

  The spring 140 is disposed inside the position restricting members 130, 130 in the through hole 112, and is on the side where the position restricting member 130 is engaged with the recess 122, that is, the end side of the through hole 112 (the diameter of the camshaft 110. It is biased toward the outer side. Both ends of the spring 140 are housed inside the cylindrical portion 132 of the position regulating member 130.

The operation of the position regulating mechanism 100 will be described with reference to FIG.
In FIG. 2A, the state of the position restriction mechanism 100 at the time of position restriction is schematically shown in a side sectional view. In FIG. 2B, the state of the position regulating mechanism 100 during movement is schematically shown in a side sectional view. Further, in the following, description will be given according to the axial direction or radial direction described in FIG.

  FIG. 2A shows a state in which the position of the cam unit 120 is restricted at one restriction position of the camshaft 110 in the position restriction mechanism 100. At this time, the position regulating member 130 is pressed outward in the radial direction by the biasing force by the spring 140 and the biasing force by the hydraulic pressure of the engine oil supplied from the hollow portion 111 to the through hole 112.

  More specifically, the position restricting member 130 includes a biasing force by the spring 140 on the bottom surface of the hemispherical portion 131 of the position restricting member 130 (the inner surface to which the cylindrical portion 132 is coupled), and the hollow portion 111 to the through hole 112. The urging force by the hydraulic pressure of the supplied engine oil acts and is pressed radially outward (black arrow shown in FIG. 2 (A)).

  The position regulating member 130 pressed outward in the radial direction is engaged with the recess 122 of the cam unit 120. The cam unit 120 in which the position regulating member 130 is engaged with the recess 122 is regulated in the axial direction with respect to the cam shaft 110.

  The position restricting member 130 engaged with the recess 122 is in addition to the urging force of the spring 140, and is based on the oil pressure of the engine oil supplied from the hollow portion 111 into the through hole 112, that is, the cylindrical portion 132 of the position restricting member 130. Since the concave portion 122 is pressed by the urging force, it is possible to ensure the holding force when the position of the cam unit 120 is restricted.

  In the position restriction mechanism 100, the cam unit 120 is configured to be movable from one restriction position to the other restriction position. FIG. 2B shows a state in which the cam unit 120 is moving from one restricting position of the camshaft 110 toward the other restricting position by the moving means described later in the position restricting mechanism 100. (The direction of the white arrow in FIG. 2B).

  At this time, the position restricting member 130 is located between the one concave portion 122 and the other concave portion 122 on the inner peripheral surface of the through hole 121, and is pressed against the inner peripheral surface of the through hole 121. It is in a state of sliding inward. When the position restricting member 130 is slid inside the through hole 112, the spring 140 is contracted more than when the position restricting member 130 is engaged with the recess 122.

  At this time, the cylindrical portions 132 and 132 of the position restricting members 130 and 130 extend into the hollow portion 111 of the camshaft 110, and the inner end of the cylindrical portion 132 of one position restricting member 130 and the other position restricting member 130. The inner end of the cylindrical portion 132 of the member 130 is close to each other. The hollow portion 111 is blocked by the peripheral surfaces of the cylindrical portions 132 and 132 extending into the hollow portion 111, and the cross-sectional area of the portion of the hollow portion 111 that communicates with the inside of the cylindrical portions 132 and 132 is reduced.

  Therefore, the amount of engine oil supplied from the hollow portion 111 to the cylindrical portions 132 and 132 decreases, and the hydraulic pressure acting on the bottom surface of the hemispherical portion 131 of the position regulating member 130 decreases.

  By reducing the hydraulic pressure acting on the bottom surface of the hemispherical portion 131 of the position regulating member 130, the urging force that presses the position regulating member 130 radially outward is reduced by the oil pressure of the engine oil (FIG. 2 ( Black arrow shown in B).

  The biasing force on the radially outer side of the position restricting member 130 is reduced, so that the position restricting member 130 pushes the cam unit 120 when the cam shaft 120 moves from one restricting position to the other restricting position. Since the pressure is reduced, the cam unit 120 can be moved from one restricted position of the camshaft 110 toward the other restricted position with a small resistance.

  In the present embodiment, the moving means is not particularly limited. For example, one end surface in the axial direction of the cam unit 120 is formed such that the amount of protrusion in the axial direction varies depending on the circumferential position, and a plunger of an electromagnetic valve that can advance or retract with respect to such an end surface is The movement of the cam unit 120 in the axial direction may be realized by abutting from the direction orthogonal to the direction.

The effect of the position restriction mechanism 100 will be described.
According to the position restriction mechanism 100, a holding force can be secured when the position of the cam unit 120 is restricted, and resistance can be suppressed when the cam unit 120 moves.

  That is, according to the position restriction mechanism 100, when the position of the cam unit 120 is restricted, the urging force by the spring 140 and the urging force by the hydraulic pressure of the engine oil supplied from the hollow portion 111 to the through hole 112 are applied to the position restriction member 130. It acts, and the holding force of the cam unit 120 can be ensured.

  Therefore, for example, when the engine is downsized and the diameter of the camshaft 110 is reduced, the holding force of the cam unit 220 can be ensured even if the length of the spring 140 is shortened.

  Further, according to the position regulating mechanism 100, when the cam unit 120 is moved, the engine oil supplied from the hollow portion 111 to the through hole 112 is reduced, the urging force due to the hydraulic pressure is reduced, and the cam unit 120 is moved. Resistance can be suppressed.

  Furthermore, according to the position restricting mechanism 100, the portion of the position restricting member 130 biased by the spring 140 that engages with the concave portion 122 of the cam unit 120 is the hemispherical hemispherical portion 131. The length of the spring 140 can be designed to be longer than that of the shape position regulating member 230, and the degree of freedom in designing the spring 140 can be increased.

DESCRIPTION OF SYMBOLS 100 Position control mechanism 110 Cam shaft 111 Hollow part 112 Through-hole 120 Cam unit 121 Through-hole 122 Recess 130 Position control member 131 Hemisphere part 132 Cylindrical part 140 Spring (elastic member)

Claims (1)

A camshaft having a hollow portion formed in an axial direction;
A cam unit that is slidably fitted in the axial direction with respect to the camshaft, and has a recess formed on a surface facing the camshaft;
A position restricting member that engages with the recess;
An elastic member that urges the position regulating member toward the side to be engaged with the recess;
With
The position regulating member includes a hemispherical portion that engages with the concave portion, and a cylindrical portion that covers the elastic member,
The hollow portion is supplied with a fluid that urges the position regulating member toward the side that engages the concave portion.
Position control mechanism for cam unit of internal combustion engine.

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