JP2007071187A - Solenoid-driven valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a solenoid-driven valve by reducing sliding resistance of a valve stem when closing the valve when torque of a torsion bar becomes maximum. <P>SOLUTION: This solenoid-driven valve has a valve 87 having the valve stem and reciprocating in the direction for extending the valve stem, and a disc 74 being a rocking member having one end slidingly supported by a housing 62 and having the other end provided with a chip 73 for pressing the valve stem in the direction for extending the valve stem. The disc 74, the chip 73 and the valve stem are positioned so that both a normal of an abutting surface of the valve stem in an abutting part of the chip 73 and the valve stem and a normal of an abutting surface of the chip 73 become the direction for extending the valve stem at a rocking angle of the disc 74 where force acting between the chip 73 and the valve stem becomes maximum. The solenoid-driven valve also has a valve closing electromagnet composed of a core 72 and a coil 80 held in a valve closing position by attracting the disc 74, and the torsion bar 68 being a first elastic member for adding force for separating the disc 74 from the valve closing electromagnet to the disc 74. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetically driven valve, and more particularly to an electromagnetically driven valve used as an intake valve or an exhaust valve of an internal combustion engine.

With respect to a conventional electromagnetically driven valve for an internal combustion engine, for example, US Pat. No. 6,467,441 (Patent Document 1) has a fulcrum at one end of a disk (armature) and the stem of an intake / exhaust valve of the internal combustion engine at the other end. A rotary drive type electromagnetically driven valve having a pressing portion for pressing an end is disclosed. In this electromagnetically driven valve, a stem end and a stem end pressing portion of a disk are in contact with each other in an R shape.
US Pat. No. 6,467,441

  However, in the rotationally driven electromagnetically driven valve, as the disk rotates, the center of curvature of both R shapes is relatively displaced from the valve shaft. If the center of curvature of both of them is offset from the shaft when the torque of the torsion bar is maximized, the valve stem is pushed laterally, and the sliding resistance of the valve stem increases. When the sliding resistance of the valve stem is large, it is necessary to increase the elastic force of the spring and the electromagnetic force by the electromagnet, and the size of the component increases. Further, in order to provide durability against a large sliding resistance, it is necessary to make the valve stem thicker or make the ball of the bearing larger.

  An object of the present invention is to provide a miniaturized electromagnetically driven valve.

  In summary, the present invention is an electromagnetically driven valve that has a valve shaft and reciprocates along a direction in which the valve shaft extends, and a valve shaft at one end that is swingably supported by a base member. And a swinging member provided with a pressing portion that presses the valve along the direction in which the valve shaft extends. The normal of the contact surface of the valve shaft at the contact portion between the pressing portion and the valve shaft and the contact of the pressing portion at the swing angle of the swing member that maximizes the force acting between the pressing portion and the valve shaft. The swing member and the valve shaft are positioned so that the normals of the surfaces are in the direction in which the valve shaft extends.

  Preferably, the electromagnetically driven valve includes a valve closing electromagnet that attracts the swing member and holds it in the closed position, and a first elastic member that applies a force to the swing member to separate the swing member from the valve closing electromagnet. Is further provided. The swing angle of the swing member that maximizes the force acting between the pressing portion and the valve shaft is an angle when the swing member is in the valve closing position.

  More preferably, the electromagnetically driven valve closes the oscillating member via the pressing portion by applying an elastic force to the valve shaft and a valve opening electromagnet that attracts and holds the oscillating member at the valve opening position. A second elastic member that applies a force separating the electromagnet for the valve to the swing member.

  Preferably, the swing member includes a core portion of a magnetic material and a non-magnetic material tip that is provided in the pressing portion and abuts on the valve shaft.

  More preferably, the tip has a concave surface that is a contact surface of the pressing portion, and the contact surface of the valve shaft is a convex surface.

  According to the present invention, a miniaturized electromagnetically driven valve can be realized.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is a diagram illustrating an examination example of an electromagnetically driven valve.
An engine that is an internal combustion engine includes a cylinder block, a cylinder head, a piston that moves up and down in the cylinder, an electromagnetically driven intake valve that is provided at an intake port of each cylinder, and an electromagnetically driven exhaust valve that is provided at an exhaust port of each cylinder. including. For example, two intake valves and two exhaust valves are provided for each cylinder.

FIG. 1 representatively shows one electromagnetically driven valve.
A crank angle sensor 6 for detecting the engine speed is attached to the cylinder block of the engine. The various sensor outputs are input to an electronic control unit (ECU) 30, which controls the injection timing and injection amount of the fuel injection valve and the ignition timing of the spark plug and controls the electromagnetic drive unit (EDU) 32. The opening timing of the electromagnetic actuator 24 that drives the intake valve or the exhaust valve is instructed.

  The electronic control unit (ECU) 30 includes a memory 31. The memory 31 stores an energization pattern corresponding to the output of the crank angle sensor 6 as a map.

  This electromagnetically driven valve has a valve 87 that has a valve shaft and reciprocates along the direction in which the valve shaft extends, and one end that is swingably supported by the housing 62 and the other end that has the valve shaft in the direction in which the valve shaft extends. And a disc 74 that is a swinging member provided with a cam follower tip 73 that is pressed along.

  The electromagnetically driven valve has a valve closing electromagnet comprising a valve closing core 72 and a coil 80 that attracts and holds the disk 74 in the valve closing position, and a first force that applies a force to the disk 74 to separate the disk 74 from the valve closing electromagnet. And a torsion bar 68 which is an elastic member.

  The electromagnetically driven valve attracts the cam follower chip 73 by applying an elastic force to the valve shaft and a valve-opening electromagnet including a valve-opening core 78 and a coil 82 that attracts the swinging member and holds it in the valve-opening position. And a lower spring 86 as a second elastic member for applying a force to the disc 74 to separate the disc from the valve opening electromagnet.

  The valve 87 moves up and down to open and close an intake port or an exhaust port provided in the cylinder head 10. An intermediate stem 76 is provided on the upper portion of the valve shaft 88 extending upward from the valve 87. A cam follower pin 75 is attached to the upper end of the intermediate stem 76. The valve 87 reciprocates along the direction in which the valve shaft 88 extends.

  A stroke ball bearing 89 is provided between the valve shaft 88 and the cylinder head 10, and the valve shaft 88 is supported movably in the vertical direction. A flange 84 is provided at the lower end of the intermediate stem 76, and a lower spring 86 is disposed between the flange 84 and the cylinder head 10.

  The electromagnetic actuator 24 includes a valve opening electromagnet and a valve closing electromagnet fixed to the housing 62. The valve opening electromagnet includes a valve opening core 78 and a coil 82. The valve closing electromagnet includes a valve closing core 72 and a coil 80. The coil 80 and the coil 82 have a monocoil structure that is connected and shared. The disc 74 is adsorbed by these opening and closing electromagnets. The disk 74 is a swinging member whose one end is supported by the housing 62 so as to be swingable.

  The disk 74 applies a downward force, that is, a valve opening direction force to the intermediate stem 76 by the elastic force of the torsion bar 68 as an upper spring. A cam follower chip 73 is attached to the other end of the disk 74. The cam follower tip 73 abuts on a cam follower pin 75 fixed to the upper end of the intermediate stem 76 and applies a downward force, that is, a valve opening direction force to the intermediate stem 76.

  On the other hand, the lower spring 86 pushes up the collar portion 84 to apply an upward force, that is, a valve closing direction force to the intermediate stem 76. As a resultant force of the torsion bar 68 and the lower spring 86, a force is generated in the opening direction when the valve 87 is fully closed, and conversely, a force is generated in the closing direction when the valve 87 is fully opened. When the distance between the disk 74 and the coil of the electromagnet to be adsorbed is large, the size of the electromagnet can be reduced by using the force of the spring.

2 is a cross-sectional view taken along the line II-II in FIG.
Referring to FIG. 2, a coil 82 is wound around the valve opening core 78. A part of the valve opening core 78 is provided with a hole for accommodating the intermediate stem 76 and the stroke ball bearing 83.

FIG. 3 is an enlarged view for explaining the force applied to the intermediate stem when the valve is closed.
Referring to FIGS. 1 and 3, the disk 74 is a ferromagnetic material that is easily attracted to an electromagnet. On the other hand, the cam follower tip 73 is preferably made of a non-magnetic material so that magnetic flux does not leak into the intermediate stem. Therefore, the cam follower chip 73 having a concave R shape protrudes from the flat disk 74.

  When the valve 74 is closed, that is, when the disk 74 is adsorbed on the coil 80 side, the elastic force of the torsion bar 68 is in the largest state.

  When the energization of the coil 80 is stopped in this state, the spring force stored in the torsion bar 68 is applied from the cam follower tip 73 to the cam follower pin 75 as a tangential force F0 in FIG.

  This force F0 can be divided into a force F2 that pushes down the intermediate stem 76 and a force F1 that pushes the intermediate stem 76 from the lateral direction.

  That is, the contact point at the time of valve opening is shifted from the axis XX of the valve, and even if the contact point is not shifted, the normal line of the cam follower tip at the contact point and the normal line at the contact point of the cam follower pin 75 are the axis X. If it deviates from −X, a component force F1 that tries to push the intermediate stem 76 in the lateral direction is generated.

  FIG. 4 is an enlarged view of the portion A1 in FIG. 1, and is a diagram for explaining the force applied to the stroke ball bearing by the lateral component force F1.

  Referring to FIG. 4, stroke ball bearing 83 includes balls 91 to 99 and a cage 90 that restrains the positions of balls 91 to 99. As shown in FIG. 4, when the component force F1 is applied to the cam follower pin 75, the ball 91 closer to the cam follower pin 75 is pushed with the force F4. A resistance against this force is generated, which causes a problem that rolling friction or sliding friction in the stroke ball bearing 83 increases.

  In addition, when the drag increases, it is necessary to increase the ball size of the ball bearing in terms of strength. For this reason, in order to increase the bearing mounting space, the upper area of the valve opening core 78 shown in FIG. Problems such as incurring costs also occur.

FIG. 5 is a diagram showing the configuration of the electromagnetically driven valve according to the embodiment of the present invention.
The electromagnetically driven valve shown in FIG. 5 has the actuator 24 entirely rotated by θ in the configuration of the electromagnetically driven valve of the examination example shown in FIG. Since the configuration of the other parts is the same as in the study example described with reference to FIG. 1, description thereof will not be repeated.

  By rotating the actuator 24 by θ, the contact of the valve shaft at the contact portion between the cam follower tip 73 and the valve shaft is obtained at the swing angle of the disk 74 where the force acting between the cam follower tip 73 and the valve shaft is maximized. The disc 74, the cam follower tip 73, and the valve shaft are positioned so that the normal of the contact surface and the normal of the contact surface of the cam follower tip 73 are in the direction in which the valve shaft extends.

  The rocking angle of the disk 74 at which the force acting between the cam follower chip 73 and the valve shaft is maximum is an angle when the disk 74 is in the closed position, that is, in the state where it is attracted to the coil 80 side. When the adsorption by the coil 80 is released, the maximum torque in the torsion bar 68 is applied to the disk 74, and the force acting between the cam follower tip 73 and the valve shaft is maximized.

  FIG. 6 is an enlarged view of the A2 portion of FIG. 5 for explaining the force applied to the intermediate stem when the valve is closed.

  As shown in FIGS. 5 and 6, in the embodiment of the present invention, when the torque of the torsion bar 68 that is the upper spring for valve opening becomes maximum, the force of the torsion bar 68 at the cam follower contact is reduced. The entire actuator is rotated by θ so that the direction matches the valve axis XX.

  By such positioning, the lateral force of the upper spring with respect to the intermediate stem 76 can be made substantially zero, and the sliding or rolling resistance of the intermediate stem 76 caused by this component force can be reduced, and the stroke ball It is possible to reduce the size and cost of the bearing.

  In the example shown in FIG. 5, the entire actuator is rotated and mounted. However, the present invention is not limited to this, and the swing that maximizes the force acting between the pressing portion that presses the valve shaft and the valve shaft is provided. The swing member, that is, the disk, so that the normal of the contact surface of the valve shaft at the contact portion between the pressing portion and the valve shaft and the normal of the contact surface of the pressing portion coincide with the valve shaft XX at an angle. And the valve shaft only needs to be positioned.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the figure which showed the example of examination of an electromagnetically driven valve. It is sectional drawing in the II-II cross section of FIG. It is an enlarged view for demonstrating the force added to the intermediate stem at the time of valve closing. FIG. 2 is an enlarged view of a portion A1 in FIG. 1 and is a diagram for explaining a force applied to a stroke ball bearing by a lateral component force F1. It is the figure which showed the structure of the electromagnetically driven valve which concerns on embodiment of this invention. FIG. 6 is an enlarged view of a portion A2 in FIG. 5 for explaining the force applied to the intermediate stem when the valve is closed.

Explanation of symbols

  6 Crank angle sensor, 10 Cylinder head, 24 Electromagnetic actuator, 30 Electronic control unit, 31 Memory, 32 Solenoid valve drive unit, 62 Housing, 68 Torsion bar, 72 Valve closing core, 73 Cam follower tip, 74 Disc, 75 Cam follower pin , 76 Intermediate stem, 78 Valve opening core, 80, 82 coil, 83, 89 stroke ball bearing, 84 collar, 86 lower spring, 87 valve, 88 valve shaft, 90 cage, 91-99 ball.

Claims (5)

A valve having a valve shaft and reciprocating along a direction in which the valve shaft extends;
A swing member provided at one end with a base member so as to be swingable, and provided with a pressing portion at the other end for pressing the valve shaft along a direction in which the valve shaft extends;
The normal line of the contact surface of the valve shaft at the contact portion between the pressing portion and the valve shaft at the swing angle of the swing member that maximizes the force acting between the press portion and the valve shaft. An electromagnetically driven valve in which the swing member and the valve shaft are positioned such that the normal line of the contact surface of the pressing portion and the normal line of the pressing portion are in the direction in which the valve shaft extends. A valve-closing electromagnet that attracts the rocking member and holds it in the valve-closing position;
A first elastic member that applies a force to the swing member to separate the swing member from the valve closing electromagnet;
2. The electromagnetic wave according to claim 1, wherein a swing angle of the swing member that maximizes a force acting between the pressing portion and the valve shaft is an angle when the swing member is in the valve closing position. Drive valve. A valve-opening electromagnet that attracts the rocking member and holds it in the valve-opening position;
And a second elastic member that applies a force to the swinging member to separate the swinging member from the valve-closing electromagnet via the pressing portion by applying an elastic force to the valve shaft. Item 3. The electromagnetically driven valve according to Item 2. The swing member is
A core of magnetic material;
2. The electromagnetically driven valve according to claim 1, comprising a tip made of a non-magnetic material provided in the pressing portion and abutting against the valve shaft. The chip is
A concave surface that is a contact surface of the pressing portion;
The electromagnetically driven valve according to claim 4, wherein the contact surface of the valve shaft is a convex surface.

Images