JP2014031745A - Electromagnetic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic actuator, which is applied to a valve lift adjustment device of an internal combustion engine and which includes two restriction pins, which makes a permanent magnet small while improving a response speed of the restriction pins.SOLUTION: An electromagnetic actuator 40 lowers an adsorption force for sucking a plunger 651 by generating a coil magnetic flux in the reverse direction with respect to one permanent magnet 501, and operates a restriction pin 601 in the advancing direction by energizing force of a spring. When the restriction pin 601 moves forward, by a front suction part 425 of a yoke 41 sucking the plunger 651, a front suction force Ffr generates for holding the restriction pin 601 in the most advanced position. As a spring load can be reduced accordingly while maintaining the holding force to a predetermined value, in accordance with that, a magnetic suction force of the permanent magnet 501 which sucks the plunger 651 in the retreating direction when the restriction pin 601 retreats can be reduced, and the permanent magnet 501 can be made to be small.

Description

  The present invention relates to an electromagnetic actuator that is applied to a valve lift adjusting device for an internal combustion engine and switches a slider position by advancing a regulating pin to engage with an engaging groove.

  2. Description of the Related Art Conventionally, in a valve lift adjustment device that adjusts the lift amount of an intake valve or an exhaust valve of an internal combustion engine, the position of a slider provided so as to be movable relative to the camshaft in an axial direction while rotating together with the camshaft is known. It has been. In addition, as a means for switching the position of the slider, either one of the two restricting pins is selectively operated according to the moving direction of the slider, and the tip of the restricting pin is engaged with the engaging groove formed in the slider. An electromagnetic actuator is known.

  For example, in the electromagnetic actuator described in Patent Document 1, permanent magnets having polarities opposite to each other in the movement direction of the restriction pin are attached to the proximal ends of the two restriction pins. Due to the magnetic field generated by energizing the coil, a repulsive force is generated in one permanent magnet, and an attractive force is generated in the other permanent magnet. Then, the regulation pin to which the permanent magnet on the side where the repulsive force is generated is operated. When the energization direction of the coil is switched, the direction of the magnetic flux of the generated magnetic field is reversed, and the other restriction pin is activated.

DE DE102009015486A1 specification

The electromagnetic actuator of Patent Document 1 directly operates the regulating pin with an electromagnetic force repelled by a magnetic field generated by a coil and a permanent magnet. However, in order to generate a sufficient repulsive force to improve the response speed of the regulation pin, it is necessary to increase the size of the coil and the permanent magnet.
Further, since the permanent magnet moves integrally with the regulation pin, if the permanent magnet is made large, the weight of the movable part increases, and the electromagnetic force of the coil is further required.
In order to solve the above problem, the applicant of the present invention is an electromagnetic actuator that is applied to a valve lift adjustment device for an internal combustion engine and that selectively operates one of two restriction pins by switching the energization direction of the coil. Has previously filed an invention relating to an electromagnetic actuator that improves the response speed of the regulating pin without increasing the size thereof (Japanese Patent Application No. 2012-169416).

In this electromagnetic actuator, two permanent magnets that attract the plunger connected to the restriction pin in the backward direction are fixed to the stationary part so that the magnetic poles are opposite to each other, and the energization direction of the coil is switched. To generate a magnetic flux in the opposite direction to one of the two permanent magnets to reduce the attracting force, and to actuate the regulating pin on the side where the attracting force of the permanent magnet is reduced in the forward direction by the biasing force of the spring. It is characterized by.
The electromagnetic force generated by the coil is used to reduce the attracting force by the permanent magnet, and it is the biasing force of the spring that operates the restriction pin. Thereby, compared with the structure which drives a regulation pin directly with the electromagnetic force which a coil produces | generates, the response speed of a regulation pin can be improved, without enlarging a coil.

  However, the electromagnetic actuator according to this application relies only on the spring force for the holding force for holding the restriction pin operated in the forward direction at the most forward position. Therefore, it is necessary to increase the spring force to some extent, and accordingly, it is necessary to ensure the magnet attracting force of the permanent magnet that attracts the plunger in the retracting direction against the spring force when the regulating pin retracts. Therefore, the possibility of downsizing the permanent magnet is limited.

  The present invention has been created in view of the above points, and an object of the present invention is to improve the response speed of the restriction pin in an electromagnetic actuator that is applied to a valve lift adjusting device for an internal combustion engine and includes two restriction pins. An object of the present invention is to provide an electromagnetic actuator that reduces the size of a permanent magnet.

The electromagnetic actuator of the present invention is further made of a soft magnetic material, and forms a magnetic circuit between the coil, the permanent magnet, and the plunger, and the end of the plunger opposite to the permanent magnet. A yoke having a front suction part facing the part is provided. When the restriction pin moves forward, the front suction portion of the yoke sucks the plunger, thereby generating a front suction force that holds the restriction pin at the most advanced position.
Since the holding force for holding the restricting pin at the most advanced position is obtained by the sum of the spring force and the front suction force, the spring force can be reduced by the amount of assist by the front suction force. Then, it is possible to reduce the magnet attracting force of the permanent magnet that attracts the plunger in the retracting direction when the regulating pin retracts accordingly. Therefore, a permanent magnet can be reduced in size.

  In addition, in the operation direction of the plunger, a cross transmission portion that overlaps with one plunger at the most retracted position and the other plunger that moves from the most retracted position to the most advanced position, and can transmit magnetic flux between the plungers. It is preferable to have.

  Furthermore, the electromagnetic actuator is preferably formed of a soft magnetic material, provided between the yoke and the plunger, and preferably includes a switching member that moves forward when either the first plunger or the second plunger moves forward. . The switching member transmits magnetic flux between the yoke and the plunger when both the first plunger and the second plunger are in the last retracted position, and when the first plunger or the second plunger moves forward, Is interrupted.

It is a figure when it starts to shift from a small lift state to a large lift state in a valve lift adjustment device to which an electromagnetic actuator according to an embodiment of the present invention is applied. It is the II-II sectional view taken on the line of FIG. It is a figure in the middle of changing from a small lift state to a large lift state in a valve lift adjustment device to which an electromagnetic actuator by one embodiment of the present invention is applied. It is the IV-IV sectional view taken on the line of FIG. It is a figure when it starts to shift from a large lift state to a small lift state in a valve lift adjustment device to which an electromagnetic actuator according to an embodiment of the present invention is applied. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is sectional drawing at the time of the deenergization of the electromagnetic actuator by one Embodiment of this invention. It is the VIII-VIII sectional view taken on the line of FIG. It is sectional drawing at the time of the 1st direction electricity supply of the electromagnetic actuator by one Embodiment of this invention. It is sectional drawing at the time of the 2nd direction electricity supply of the electromagnetic actuator by one Embodiment of this invention. It is a principal part expanded sectional view of FIG. It is the XII-XII sectional view taken on the line of FIG. In the electromagnetic actuator by one Embodiment of this invention, it is a characteristic view which shows the change of the magnet attraction force by electricity supply. (A) Comparative example, (b) It is a characteristic view which shows the relationship between the stroke of the regulation pin in the electromagnetic actuator by one Embodiment of this invention, a spring force, and a magnet attractive force. It is sectional drawing at the time of the 1st direction energization of the electromagnetic actuator of a comparative example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(One embodiment)
An electromagnetic actuator according to an embodiment of the present invention is applied to a valve lift adjusting device that adjusts a lift amount of an intake valve of an internal combustion engine.

First, the valve lift adjusting device will be described with reference to FIGS. In the following description, “FIG. 1 etc.” refers to FIGS. 1, 3 and 5, and “FIG. 2 etc.” refers to FIGS. 2, 4 and 6.
As shown in FIGS. 1 to 6, the valve lift adjusting device 10 is linked via rollers 31 and 32 and swing arms 33 and 34 by a cam integrally provided on a slider 21 that rotates together with the camshaft 11. The lift amount of the intake valves 91 and 92 is adjusted.

The camshaft 11 rotates in a fixed direction in conjunction with a crankshaft (not shown). This rotational direction corresponds to the counterclockwise direction when the camshaft 11 is viewed from the left side in FIG.
As shown in FIG. 2 and the like, the camshaft 11 has spline external teeth formed on the outer surface of the portion where the slider 21 is fitted. In addition, illustration of a spline external tooth is abbreviate | omitted in FIG.
The cylindrical slider 21 is provided so as to be able to move relative to the camshaft 11 in the axial direction while rotating together with the camshaft 11 by engaging the spline inner teeth formed on the inner surface with the spline outer teeth of the camshaft 11. Yes. That is, the slider 21 is provided so as to be capable of reciprocating in the axial direction between two slider limiters 12 and 22 fixed to the camshaft 11 in a bowl shape.

At both ends of the slider 21, a switching unit 20, small lift cams 18 and 28, and large lift cams 19 and 29 are integrally provided. The switching unit 20 switches the position of the slider 21 in the axial direction with respect to the camshaft 11.
The switching unit 20 includes a first engagement groove 14 composed of a front stage part 15, a transition part 16, and a rear stage part 17, and a second engagement groove 24 composed of a front stage part 25, a transition part 26, and a rear stage part 27 as shown in FIG. Are formed symmetrically. The two engaging grooves 14 and 24 are formed such that the rear stage portions 17 and 27 are overlapped with each other and present a “Y” shape in the viewing direction of FIG.

The front step portion 15 and the rear step portion 17 of the first engagement groove 14 extend in directions orthogonal to the axis at different positions in the axial direction. Further, as shown in FIG. 2, the depth of the groove becomes shallower toward the front in the rotational direction as shown in FIG. 2, and the depth of the groove becomes shallower toward the rear in the rotational direction as shown in FIG. Become. The transition part 16 connects the front stage part 15 and the rear stage part 17 while tilting so that the front in the rotational direction approaches the front stage part 15 and the rear in the rotational direction approaches the rear stage part 17 with respect to the direction orthogonal to the axis. ing.
The same applies to the second engagement groove 24.

The electromagnetic actuator 40 applied to the valve lift adjusting device 10 includes two restriction pins 601 and 602 corresponding to the first engagement groove 14 and the second engagement groove 24, respectively.
When the electromagnetic actuator 40 advances the first restricting pin 601 in synchronization with the rotation timing of the camshaft 11 and engages the first engaging groove 14, the slider 21 moves along with the rotation of the camshaft 11. Move to the 12th side. On the other hand, when the electromagnetic actuator 40 advances the second restricting pin 602 in synchronization with the rotation timing of the camshaft 11 and engages with the second engagement groove 24, the slider 21 moves along with the rotation of the camshaft 11. Move to the slider limiter 22 side. This detailed operation will be described later.

  The first small lift cam 18 and the first large lift cam 19 are provided adjacent to each other between the left end of the slider 21 and the switching portion 20 in FIG. As shown in FIG. 2 and the like, the first small lift cam 18 and the first large lift cam 19 are eccentric to the outside with respect to the reference circle in one direction of rotation. Further, the first large lift cam 19 is formed so that the amount of eccentricity from the reference circle is larger than that of the first small lift cam 18.

  The second small lift cam 28 and the second large lift cam 29 are provided adjacent to each other at the right end of the slider 21 in FIG. The second small lift cam 28 and the second large lift cam 29 are offset in the same direction in the axial direction with respect to the first small lift cam 18 and the first large lift cam 19 and are eccentric in the rotational direction. The portions are arranged in a direction shifted by about 180 °.

The rollers 31 and 32 and the swing arms 33 and 34 correspond to the two sets of the small lift cams 18 and 28 and the large lift cams 19 and 29, respectively. The rotational movement of the camshaft 11 is reciprocated by the intake valves 91 and 92. Convert to
The rollers 31 and 32 are interposed between the small lift cams 18 and 28 and the large lift cams 19 and 29 and the central portions of the swing arms 33 and 34.

  The swing arms 33 and 34 have one end abutting against the lash adjusters 35 and 36 and the other end abutting against the intake valves 91 and 92. The swing arms 33, 34 swing with the contact portions with the lash adjusters 35, 36 as fulcrums so that the other ends of the arms approach or separate from the intake valves 91, 92. The lash adjuster 35 corresponding to the swing arm 33 is shown in FIG. 2 and the like, and the lash adjuster 36 corresponding to the swing arm 34 is not shown.

Next, the operation of the valve lift adjusting device 10 will be described with reference to FIGS.
As shown in FIGS. 1 and 2, when the slider 21 is on the slider limiter 22 side, the roller 31 contacts the outer peripheral surface of the eccentric portion of the small lift cam 18 and pushes down the swing arm 33. As a result, the intake valve 91 of the cylinder head 90 is opened by a relatively small lift amount L1. Further, the roller 32 abuts on the outer peripheral surface of the eccentric portion of the small lift cam 28 at a phase shifted by about 180 ° from the roller 31 and pushes down the swing arm 34. As a result, the intake valve 92 is opened by the lift amount L1.
Hereinafter, this state of the valve lift adjusting device 10 is referred to as a “small lift state”. In contrast, a state in which the roller 31 is in contact with the outer peripheral surface of the eccentric portion of the large lift cam 19 is referred to as a “large lift state”.

In the small lift state, the first restriction pin 601 of the electromagnetic actuator 40 is located immediately above the front stage portion 15 of the first engagement groove 14. Therefore, when shifting from the small lift state to the large lift state, the electromagnetic actuator 40 moves the first restriction pin 601 forward at the timing when the rotational position of the camshaft 11 becomes the position shown in FIGS. Engage with the engaging groove 14.
When the slider 21 rotates together with the camshaft 11 in a state where the first restriction pin 601 is fitted in the first engagement groove 14, the position of the groove in which the first restriction pin 601 is fitted passes through the transition part 16 from the front stage part 15. While moving to the rear stage 17, the slider 21 moves to the slider limiter 12 side as indicated by an arrow X1 in FIG.

The position P1 of the cams 18 and 19 when the slider 21 rotates 90 ° from the position P0 shown in FIGS. 1 and 2 is shown by solid lines in FIGS. Also, the positions P2 and P3 of the cams 18 and 19 when the slider 21 rotates 180 ° and 270 ° from the position P0 are indicated by broken lines in FIG. In the rotation range from the position P1 to the position P3, since the roller 31 is in contact with the outer peripheral surface of the reference circular portion of the cams 18 and 19, the intake valves 91 and 92 are kept closed.
Further, at the rotational position past the position P3, the depth of the groove of the rear stage portion 17 becomes shallow, and the bottom wall of the rear stage portion 17 pushes back the first restriction pin 601 of the electromagnetic actuator 40.

  Thereafter, as shown in FIGS. 5 and 6, at the position P <b> 4 where the slider 21 has rotated 360 ° from the position P <b> 0, the roller 31 comes into contact with the outer peripheral surface of the eccentric portion of the large lift cam 19 and pushes down the swing arm 33. . That is, the valve lift adjusting device 10 is in a large lift state. As a result, the intake valve 91 of the cylinder head 90 is opened by a relatively large lift amount L2. Further, the roller 32 abuts on the outer peripheral surface of the eccentric portion of the large lift cam 29 at a phase shifted by about 180 ° from the roller 31 and pushes down the swing arm 34. As a result, the intake valve 92 is opened by the lift amount L2.

In the large lift state, the second restriction pin 602 of the electromagnetic actuator 40 is positioned immediately above the front stage portion 25 of the second engagement groove 24. Therefore, when shifting from the large lift state to the small lift state, the electromagnetic actuator 40 advances the second restriction pin 602 at the timing when the rotational position of the camshaft 11 has reached the position shown in FIGS. Engage with the engaging groove 24.
When the slider 21 rotates together with the camshaft 11 in a state where the second restriction pin 602 is fitted in the second engagement groove 24, the position of the groove in which the second restriction pin 602 is fitted passes through the transition part 26 from the front stage part 25. While moving to the rear stage 27, the slider 21 moves to the slider limiter 22 side as indicated by an arrow X2 in FIG.

As described above, the valve lift adjusting device 10 controls the operation of the electromagnetic actuator 40 in synchronization with the rotation timing of the camshaft 11, thereby reducing the lift amount of the intake valves 91 and 92 to the lift amount L1 and the lift amount L2. You can switch to either.
Specifically, the operating conditions can be appropriately improved by adjusting the valve lift amount according to the rotational speed and load of the internal combustion engine.

Next, the detailed structure of the electromagnetic actuator which is the principal part of this invention is demonstrated with reference to FIGS.
As shown in FIGS. 7 to 12, the electromagnetic actuator 40 has two restriction pins 601 and 602 arranged in parallel, and one of them is alternatively operated as an “operation side restriction pin”. In the following description, “operating side” is also referred to as “on side”, and “non-operating side” is also referred to as “off side”.

The electromagnetic actuator 40 includes two plungers 651 and 652, springs 751 and 752, permanent magnets 501 and 502, and adapters 551 and 552 corresponding to the two restriction pins 601 and 602.
Here, members whose three-digit code ends with “1” correspond to each other, and members whose three-digit code ends with “2” correspond. Hereinafter, “first” is added before the name of the member whose 3-digit code ends with “1”, and “second” is added before the name of the member whose 3-digit code ends with “2”. . However, “421, 422, 491, 492” is an exception.

  The regulation pins 601 and 602 and the plungers 651 and 652 correspond to “movable parts”. The first restriction pin 601 and the first plunger 651 are integrally coupled on the pin axis O1, and reciprocate from the most retracted position shown in FIG. 7 to the most advanced position shown in FIG. Further, the second restriction pin 602 and the second plunger 652 are integrally coupled on the pin shaft O2, and reciprocate from the most retracted position shown in FIG. 7 to the most advanced position shown in FIG.

  Here, the last retracted position is “zero stroke”, the most advanced position is “full stroke”, and the advance distance from the last retracted position is indicated by a stroke (mm). In the following description, “forward direction” or “forward” corresponds to the downward direction of FIGS. 7 and 9 to 11, and “reverse direction” or “rearward” is the upper direction of FIGS. 7 and 9 to 11. Corresponds to the direction. A direction in which the regulation pins 601 and 602 advance and retreat is referred to as an “axial direction” of the electromagnetic actuator 40, and a direction orthogonal to the axial direction of the electromagnetic actuator 40 is referred to as a “radial direction”.

Further, the electromagnetic actuator 40 includes a yoke 41, a holder 46, a coil 47, a sleeve 70 and the like in common for the two sets of restriction pins 601, 602 and the like. These yoke 41, holder 46, coil 47, sleeve 70, permanent magnets 501 and 502, adapters 551 and 552, etc. constitute a “stationary part”.
Hereinafter, after describing the structure of a stationary part in order, the structure of a movable part is demonstrated.

The yoke 41 is formed of a soft magnetic material such as iron in a double cylindrical shape, and constitutes a magnetic circuit between the coil 47, the permanent magnets 501, 502, the plungers 651, 652, and the like.
In the present embodiment, as shown in FIGS. 8 and 12, the radial cross-sectional shape of the yoke 41 is a common tangent line between a semicircle centered on the pin axis O1 and a semicircle centered on the pin axis O2. It has an oval shape connected by The yoke 41 is formed symmetrically with respect to the virtual plane V including the pin axis O1 and the pin axis O2. In the following description, the term “cross-sectional shape” simply means a radial cross-sectional shape, and the term “cross-sectional area” means a radial cross-sectional area.
The outer cylindrical portion 42 of the yoke 41 is formed with an opening 421 at the rear and a bottom wall 422 at the front. The shaft portions 611 and 612 of the regulation pins 601 and 602 are inserted through the bottom wall 422.
As shown in FIG. 12, the inner cylinder portion 430 of the yoke 41 is provided inside the bobbin 46 and outside the plungers 651 and 652, and is formed in a cylindrical shape having an oval cross section.

Inside the yoke inner cylinder part 430, a nonmagnetic cylinder part 455 formed in a cylindrical shape with a nonmagnetic material is provided in a range where the distance from the bottom wall 422 is less than a predetermined value. On the other hand, in the range where the distance from the bottom wall 422 is equal to or greater than a predetermined value, the inner wall of the yoke inner cylindrical portion 430 that is a magnetic body is exposed. The exposed inner wall includes a concave curved inner wall 431 facing the outer wall of the first plunger 651, a concave curved inner wall 432 facing the outer wall of the second plunger 652, and a planar inner wall 433 that connects the inner wall 431 and the inner wall 432. Consists of
The exposed inner walls 431, 432, 433 always overlap the plungers 651, 652 while the plungers 651, 652 move from the most retracted position to the most advanced position. However, a space Gp is formed between the exposed inner walls 431, 432, 433 and the plungers 651, 652 in which a cylindrical portion 673 of the switching member 67 described later can be fitted. The space Gp magnetically suppresses transmission of magnetism as an air gap.

  In the present embodiment, a cross transmission portion 434 is provided between the first plunger 651 and the second plunger 652 in the radial direction so as to be separated from the yoke inner cylinder portion 430 and constitute a magnetic circuit. The cross transmission portion 434 is formed of a soft magnetic material such as iron and has concave walls 435 and 436 and a flat wall 437. The concave walls 435 and 436 are respectively formed along the outer peripheral portions of the first plunger 651 and the second plunger 652 facing each other. The flat wall 437 is formed along a common tangent line between the outer walls of the first plunger 651 and the second plunger 652, and faces the exposed inner wall 433 of the flat portion of the yoke inner cylinder 430. A portion along a straight line connecting the pin axes O1 and O2 is the narrowest portion 438 having the narrowest width.

Between the cross transmission part 434 and the yoke bottom wall 422, a nonmagnetic column part 454 made of a nonmagnetic material and having the same cross-sectional shape as the cross transmission part 434 is provided. With this nonmagnetic column portion 454, the axial position of the cross transmission portion 434 is arranged at a position corresponding to the exposed inner walls 431, 432, 433 of the yoke inner cylinder portion 430.
That is, the cross transmission portion 434 is magnetically isolated from the bottom wall 422 of the yoke 41 and the inner cylinder portion 430 before the plungers 651 and 652 and the switching member 67 are assembled. Further, the cross transmission portion 434 always overlaps with the outer peripheral portion of the plungers 651 and 652 facing each other while any one of the plungers 651 and 652 moves from the most retracted position to the most advanced position.

The stator 44 is formed in a plate shape with a soft magnetic material such as iron and covers the opening 421 of the yoke outer cylinder portion 42.
The holder 45 is formed of a non-magnetic material and is supported between the bobbin 46 and the stator 44 at the rear of the yoke 41. As shown in FIG. 8, the holder 45 is formed with two accommodating portions 451 and 452 that respectively accommodate the permanent magnets 501 and 502 with the partition 453 interposed therebetween.

The bobbin 46 is made of resin and covers the periphery of the coil 47 for insulation. The bobbin 46 is provided between the outer cylinder part 42 and the inner cylinder part 43 in the radial direction in front of the yoke 41. Further, the bobbin 46 is provided between the outer tube portion 42 and the holder 45 in the radial direction at the rear in the yoke 41. The connector 48 is formed of resin integrally with the bobbin 46.
The rear end surface of the bobbin 46 in the axial direction and the stator 44 are sealed by an O-ring 491. A space between the outer wall of the bobbin 46 in the radial direction and the inner wall of the yoke outer cylinder portion 42 is sealed by an O-ring 492.

  The coil 47 generates coil magnetic flux when energized from an external power source 81 via the connector 48. This coil magnetic flux flows through the yoke 41, the stator 44, the plungers 651 and 652, etc., which are soft magnetic materials. Further, by switching the energization direction by the external energization direction switching means 82, the coil 47 generates a coil magnetic flux in the opposite direction.

The permanent magnets 501 and 502 are fixed to a holder 45 that is a stationary part. Specifically, as shown in FIG. 12, the side walls 52 of the permanent magnets 501 and 502 are fitted into the accommodating portions 451 and 452 of the holder 45, respectively.
As shown in FIG. 8, in this embodiment, the permanent magnets 501 and 502 have a circular cross-sectional shape. The diameters of the permanent magnets 501 and 502 are set larger than the diameters of the corresponding plungers 651 and 652. Magnet axes Q1 and Q2 of permanent magnets 501 and 502 are arranged on both outer sides of pin axes O1 and O2 on a virtual plane. The distance dm between the permanent magnets 501 and 502 is set to be equal to the distance dp between the plungers 651 and 652.

  Further, the first permanent magnet 501 and the second permanent magnet 502 are magnetized in the axial direction so that the magnetic pole directions are parallel to the operating directions of the first plunger 651 and the second plunger 652 and opposite to each other. . The first permanent magnet 501 has an S pole on the stator 44 side and an N pole on the first plunger 651 side. The second permanent magnet 502 has an N pole on the stator 44 side and an S pole on the second plunger 652 side.

In addition, in this embodiment, adapters 551 and 552 made of a soft magnetic material such as iron are provided at the end portions of the permanent magnets 501 and 502 on the plungers 651 and 652 side.
As shown in FIG. 12, the rear end surfaces 56 of the adapters 551 and 552 are in contact with the front end surfaces 53 of the permanent magnets 501 and 502 or close to each other through a minute gap. Further, the end surfaces 58 of the plungers 651 and 652 are in contact with the front end surfaces 58 of the adapters 551 and 552 when the power is not supplied.

  Here, taking the first permanent magnet 501 and the first adapter 551 as an example, the area Am of the end surface 53 of the first permanent magnet 501 is larger than the area Ap of the end surface 66 of the first plunger 651. Corresponding to this, in the first adapter 551, the area of the end surface 56 on the permanent magnet side conforms to the area Am of the end surface 53 of the first permanent magnet 501, and the area of the end surface 58 on the plunger side of the end surface 66 of the first plunger 651. According to area Ap. Therefore, the cross-sectional area gradually decreases from the end surface 56 on the permanent magnet side toward the end surface 58 on the plunger side. The side wall 57 of the first adapter 551 is formed such that the outer side in the radial direction is a slope, and the inner side in the radial direction is a plane parallel to the pin axis O1. That is, the first adapter 551 is formed in a substantially truncated cone shape.

With this configuration, the adapters 551 and 552 function as “magnetic collecting members” that are magnetized by the permanent magnets 501 and 502 and collect the magnetic flux of the permanent magnets 501 and 502 on the plungers 651 and 652.
Further, if the adapters 551 and 552 are not provided, when the permanent magnets 501 and 502 attract the plungers 651 and 652, the permanent magnets 501 and 502 may break due to the collision of the plungers 651 and 652, and the actuator may become inoperable. is there. Therefore, by providing the adapters 551 and 552 between them, the impact when the plungers 651 and 652 are attracted to the permanent magnets 501 and 502 is reduced. That is, the adapters 551 and 552 also function as “buffer members”.

The sleeve 70 includes a flange portion 71 and a main body portion 72.
The flange portion 71 is joined to the bottom wall 422 in front of the yoke 41. A gap between the flange portion 71 and the bottom wall 422 is sealed with an O-ring 493.
The main body 72 has accommodation holes 721 and 722 for accommodating the regulation pins 601 and 602 and the springs 751 and 752. The housing holes 721 and 722 communicate with the plunger holes 431 and 432 of the yoke inner cylinder portion 43. The bushes 731 and 732 are inserted into the rear openings of the receiving holes 721 and 722 after the flanges 631 and 632 of the regulating pins 601 and 602 are received in the receiving holes 721 and 722. Sliding holes 751 and 752 are formed in the hole bottoms 741 and 742 of the receiving holes 721 and 722, respectively.

  The springs 751 and 752 are extrapolated to the shaft bodies 611 and 612 of the restriction pins 601 and 602, and both ends are supported between the bushes 731 and 732 and the flange portions 631 and 632. The springs 751 and 752 bias the flanges 631 and 632 away from the bushes 731 and 732, so that the regulation pins 601 and 602 are biased in the forward direction.

Next, the restriction pins 601 and 602 and the plungers 651 and 652 which are movable parts will be described by taking the first restriction pin 601 and the first plunger 651 as an example.
The first restricting pin 601 is formed such that a connecting portion 621 connected to the first plunger 651 and a flange portion 631 constituting a seating surface of the first spring 751 are coaxially formed on the pin shaft O1 with respect to the shaft body 611. ing. For example, the collar portion 631 may be formed by press-fitting a collar separate from the shaft main body 611, or may be manufactured integrally with the shaft main body 611.

  Most of the shaft main body 611 except for the distal end portion 641 is accommodated in the sleeve 70. The shaft body 611 is guided in the hole of the bush 731 at the rear of the sleeve 70, and is slid by being guided in the sliding hole 751 at the front of the sleeve 70. The distal end portion 641 protrudes from the sleeve 70 and engages with the first engagement groove 14 of the valve lift adjusting device 10 when moving forward.

The first plunger 651 is formed in a cylindrical shape with a soft magnetic material such as iron. The first plunger 651 is connected to the connecting portion 621 of the first restriction pin 601 and moves forward and backward integrally with the first restriction pin 601.
The outer diameter of the first plunger 651 is formed larger than the outer diameter of the shaft main body 611 of the first restricting pin 601, and the step surface due to the difference in outer diameter is the front end surface 665 of the first plunger 651. The front end surface 665 of the first plunger 651 faces the front suction part 425 of the yoke bottom wall 422, and abuts the front suction part 425 at the most advanced position or closes through a minute gap.

  The above configuration is the same for the second restriction pin 602 and the second plunger 652. The tip portion 642 of the second restriction pin 602 engages with the second engagement groove 24 of the valve lift adjusting device 10 during advance. Further, the front end surface 666 of the second plunger 652 faces the front suction portion 426 of the yoke bottom wall 422 and abuts the front suction portion 426 at the most advanced position of the second restriction pin 602 or has a minute gap. Proximity through.

Furthermore, in this embodiment, the switching member 67 which is another movable member, and the switching spring 68 which urges | biases the switching member 67 back are provided.
The switching member 67 is a soft magnetic body and is formed in a cylindrical shape having an oval cross-sectional shape. A peripheral edge 674 that protrudes toward the inner peripheral side is formed at the front end of the cylindrical part 673.
The cylindrical portion 673 is provided along the outer peripheral portion of the first plunger 651 and the second plunger 652 that are not opposed to each other, and comprehensively surrounds the plungers 651 and 652. The peripheral edge 674 engages both outer edges of the front end surface 665 of the first plunger 651 and the front end surface 666 of the second plunger 652 when the first plunger 651 and the second plunger 652 are in the last retracted position. Further, when one of the first plunger 651 and the second plunger 652 moves forward, the peripheral edge portion 674 engages with the outer edge of the front end surface of the moved plunger. Thereby, the switching member 67 advances in conjunction with the advanced plunger.

  The switching member 67 has the same axial position as the exposed inner walls 431, 432, and 433 of the yoke inner cylinder portion 430 at the last retracted position (the position shown in FIG. 7 or the position shown by the two-dot chain line in FIG. 11). Magnetic flux can be transferred between the yoke inner cylinder portion 430 and the plungers 651 and 652. On the other hand, when the stroke equal to or higher than the height of the cylindrical portion 673 is advanced, the axial position is included in the range of the non-magnetic cylindrical portion 455, so that the magnetic flux is transferred between the yoke inner cylindrical portion 430 and the plungers 651 and 652. Is cut off. As described above, the switching member 67 has a function of switching on / off of magnetic flux transmission according to the axial position.

Finally, the configuration around the electromagnetic actuator 40 will be described. Outside the electromagnetic actuator 40, a power supply 81, an energization direction switching unit 82, and a connection wiring 84 are provided as peripheral components.
The power supply 81 supplies a drive current to the coil 47 by connecting the connection wiring 84 to the connector 48.
The energization direction switching means 82 switches the direction of energization of the current supplied from the power source 81 to the coil 47 or interrupts energization.

Next, the operation of the electromagnetic actuator 40 configured as described above will be described with reference to the characteristic diagrams of FIGS. 7 and 9 to 11 and FIGS. 13 and 14. 13 and 14, the horizontal axis indicates the strokes of the plungers 651 and 652 and the restriction pins 601 and 602. “S0” of stroke 0 (mm) corresponds to a “last retracted position” where the plunger end surface 66 abuts against the adapter end surface 58. In the vertical axis, the positive side indicates the force in the forward direction, and the negative side indicates the force in the backward direction.
FIG. 13 shows the behavior when the plunger starts to advance in the vicinity of the zero stroke S0. FIG. 14 shows the relationship between the forces acting on the restriction pins 601 and 602 and the plungers 651 and 652 over the entire stroke range from the zero stroke S0 to the full stroke Sf, and particularly the characteristics relating to the holding force of the restriction pins at the most advanced position. Is shown.

(When not energized)
During the non-energization shown in FIG. 7, both the first restriction pin 601 and the second restriction pin 602 are held at the last retracted position. Here, the first restriction pin 601 will be described as an example.
As shown in FIG. 13, the magnet attracting force Fm <b> 0 by the first permanent magnet 501 and the spring force Fsp by the first spring 751 act on the first plunger 651 at the time of non-energization.

The magnet attracting force Fm0 is a negative force acting in the direction in which the first plunger 651 is retracted, and the absolute value decreases as the stroke increases. The positive spring force Fsp is a positive force acting in the direction in which the first plunger 651 is advanced, and decreases linearly as the stroke increases. For reference in comparing the absolute value with the magnet attracting force, the reverse force that balances the spring force is shown as “−Fsp”.
Since the absolute value of the magnet attracting force Fm0 is set to exceed the spring force Fsp at the zero stroke S0, the first plunger 651 is attracted and held by the first permanent magnet 501.

  At this time, the switching member 67 is held at a position where the peripheral edge portion 674 engages with the front end surfaces 665 and 666 of the plungers 651 and 652 by the urging force of the switching spring 68. The cylinder portion 673 is fitted into the space Gp (see FIG. 11) between the yoke inner cylinder portion 430 and the plungers 651 and 652.

On the other hand, the second plunger 652 is similarly attracted and held by the second permanent magnet 502 for the second restriction pin 602.
As a result, the tip portions 641 and 642 of the first restricting pin 601 and the second restricting pin 602 are both maintained at the last retracted position when not energized, and are separated from the engaging grooves 14 and 24 in the valve lift adjusting device 10.

(During energization in the first direction)
As shown in FIG. 9, when a current in the first direction is passed through the coil 47, the coil 47 generates a coil magnetic flux Φsol1 that is opposite to the magnetic flux Φm1 of the first permanent magnet 501. That is, the magnetic flux Φm1 of the first permanent magnet 501 penetrates downward from the S pole toward the N pole, whereas the coil magnetic flux Φsol1 penetrates the first permanent magnet 501 upward in the figure. As described above, the energization in the first direction is “the energization that generates the coil magnetic flux in the direction opposite to the magnetic flux of the magnet” for the first permanent magnet 501 (hereinafter referred to as “reverse direction energization”).

  At this time, the switching member 67 delivers the coil magnetic flux Φsol1 between the inner wall of the yoke inner cylinder portion 430 and the outer wall of the first plunger 651. Since the magnetic flux penetrating the first permanent magnet 501 is canceled by the coil magnetic flux Φsol1, the magnet attractive force of the first permanent magnet 501 decreases to Fm− shown in FIG. In other words, the first permanent magnet 501 is “demagnetized” by the coil magnetic flux Φsol1.

  Further, since the first adapter 551 is provided between the first permanent magnet 501 and the first plunger 651, the adapter end surface 58 is equivalent to the thickness Ta of the first adapter 551 with respect to the permanent magnet end surface 53. The magnet attracting force Fm decreases. Therefore, as shown in FIG. 13, the absolute value of the magnet attractive force Fm− during reverse energization corresponds to the position of the plunger end surface 66 at the zero stroke S0 even if the permanent magnet end surface 53 exceeds the spring force Fsp. The adapter end surface 58 to be set can be set to be less than the spring force Fsp. In other words, the thickness Ta of the first adapter 551 is set so that the absolute value of the magnet attracting force Fm− is less than the spring force Fsp at the zero stroke S0 due to the reverse coil magnetic flux.

As a result, since the absolute value of the magnet attracting force Fm− at the zero stroke S0 is smaller than the spring force Fsp, the first restricting pin 601 is positive between the spring force Fsp of the first spring 751 and the magnet attracting force Fm−. Move forward with the resultant force. And even if it stops energizing after exceeding the threshold stroke St in which the absolute value of the magnet attractive force Fm0 and the spring force Fsp become equal, the first restriction pin 601 continues to advance by the spring force Fsp. That is, when energizing in the first direction, the first restriction pin 601 operates as an “operation side restriction pin”.
At this time, the switching member 67 moves forward against the urging force of the switching spring 68 in conjunction with the advancement of the first plunger 651.

When the front end surface 665 of the first plunger 651 comes close to the opposed front suction portion 425 at a position immediately before the full stroke Sf, the front suction portion 425 generates a front suction force Ffr. This operation will be described with reference to FIG.
Assuming that there is no cross transmission portion 434 and no magnetic flux is transmitted between the plungers 651 and 652 in the magnetic flux transmission path between the front suction portion 425 and the off-side second permanent magnet 502, “front suction portion 425 → The yoke bottom wall 422 → the yoke outer cylinder portion 42 → the stator 44 → the second permanent magnet 502 ”is a detour path that passes through the outside of the coil 47. In this case, there are many magnetic leaks in the middle of the path, and it is considered that the magnetic flux Φm2 of the second permanent magnet 502 is difficult to be effectively transmitted to the front attracting portion 425.

  On the other hand, as shown in FIG. 11, the cross transmission portion 434 becomes a magnetic flux transmission path, so that “front suction portion 425 → on-side first plunger 651 → cross transmission portion 434 → off-side second plunger 652”. The shortest magnetic path that passes through the inside of the coil 47, that is, “second permanent magnet 502” is formed. As a result, the magnetic flux Φm2 of the second permanent magnet 502 is effectively transmitted to the front suction unit 425, and the front suction unit 425 generates a front suction force Ffr.

Here, the cross transmission portion 434 is magnetically isolated from the yoke bottom wall 422 by the nonmagnetic column portion 454, and magnetic flux leakage to the bottom wall 422 is suppressed.
Furthermore, when the switching member 67 moves forward in conjunction with the first plunger 651, the space Gp between the yoke inner cylinder portion 430 and the plungers 651 and 652 is opened, thereby forming an air gap. Therefore, leakage of magnetic flux from the plungers 651 and 652 to the yoke inner cylinder portion 430 is also suppressed.

By the front suction force Ffr thus generated, the first plunger 651 is urged to move from the immediately preceding position to the most advanced position, and after reaching the most advanced position, the valve lift adjusting device 10 vibrates and other external forces. It is held at the most advanced position so that it does not move due to the like. That is, a state where the “holding force” at the most advanced position is received.
As a result, the tip 641 of the first restriction pin 601 engages with the engagement groove 14 of the valve lift adjustment device 10. Then, the slider 21 is moved in the direction of the arrow X1 in FIG. 1 by the rotation of the camshaft 11, and the valve lift amount is switched from the lift amount L1 to the lift amount L2.

Following the movement of the slider 21, the tip portion 641 of the first restriction pin 601 is pushed back against the holding force by the rotation of the switching unit 20, so that the first plunger 651 moves from the full stroke Sf to the threshold stroke St. Retreat to less than stroke area.
Since the absolute value of the magnet attracting force Fm0 of the first permanent magnet 501 exceeds the spring force Fsp in the region less than the threshold stroke St, the first plunger 651 is attracted in the backward direction until it abuts on the first adapter 551.
At this time, the 1st adapter 551 can avoid that the 1st plunger 651 collides with the 1st permanent magnet 501 directly as a buffer member, and can prevent the crack of the 1st permanent magnet 501 by an impact.

  On the other hand, the switching member 67 delivers the coil magnetic flux Φsol1 between the inner wall of the yoke inner cylinder portion 430 and the outer wall of the second plunger 652 until the first plunger 651 starts moving forward during energization in the first direction. Therefore, for the second permanent magnet 502, the coil magnetic flux Φsol1 in the same direction as the magnetic flux Φm2 passes through the second permanent magnet 502. As described above, the energization in the first direction is “the energization that generates the coil magnetic flux in the same direction as the magnetic flux of the magnet” (hereinafter referred to as “the same direction energization”) for the second permanent magnet 502.

  Since the magnetic flux penetrating the second permanent magnet 502 is superimposed by the coil magnetic flux Φsol1 generated by energization in the same direction, the absolute value of the magnet attracting force of the second permanent magnet 502 increases to Fm + shown in FIG. Therefore, the second plunger 652 is attracted and held by the second permanent magnet 502 with a greater force than when no power is supplied. Therefore, the second restriction pin 602 is maintained at the last retracted position as in the case of non-energization.

(When energizing in the second direction)
As shown in FIG. 10, when a current in the second direction is applied to the coil 47, the coil 47 is in the same direction as the magnetic flux Φm1 of the first permanent magnet 501 and opposite to the magnetic flux Φm2 of the second permanent magnet 502. Magnetic flux Φsol2 is generated. That is, energization in the second direction is reverse direction energization for the second permanent magnet 502. Therefore, when energizing in the second direction, the second permanent magnet 502 is demagnetized contrary to when energizing in the first direction, and the absolute value of the magnet attracting force Fm0 that attracts the second plunger 652 decreases. The second restriction pin 602 operates as an “operation-side restriction pin” by the spring force Fsp of the second spring 752.
At this time, the switching member 67 moves forward against the urging force of the switching spring 68 in conjunction with the advancement of the second plunger 652.

When the front end surface of the second plunger 652 comes close to the opposing front suction portion 426 at a position immediately before the full stroke Sf, the front suction portion 426 generates a front suction force Ffr as described above. By this front suction force Ffr, the second plunger 652 is urged to move from the immediately preceding position to the most advanced position, and is held at the most advanced position after reaching the most advanced position.
As a result, the tip 642 of the second restriction pin 602 engages with the engagement groove 24 of the valve lift adjusting device 10. Then, the slider 21 is moved in the direction of the arrow X2 in FIG. 5 by the rotation of the camshaft 11, and the valve lift amount is switched from the lift amount L2 to the lift amount L1.

Following the movement of the slider 21, the tip portion 642 of the second restriction pin 602 is pushed back by the rotation of the switching unit 20, and the second plunger 652 comes into contact with the second adapter 552 by the attractive force of the second permanent magnet 502. Is sucked in the backward direction.
On the other hand, since the energization in the second direction is the same direction energization for the first permanent magnet 501, the first plunger 651 is attracted and held by the first permanent magnet 501 with a force larger than that during non-energization. Accordingly, the first restriction pin 601 is maintained at the last retracted position as in the case of non-energization.

  As described above, in the electromagnetic actuator 40, neither the first restriction pin 601 nor the second restriction pin 602 operates when de-energized, only the first restriction pin 601 operates when energized in the first direction, and the first restriction pin 601 operates when energized in the second direction. 2 Only the regulation pin 602 operates. That is, the electromagnetic actuator 40 can selectively operate one of the two restriction pins 601 and 602 according to the switching operation by the energization direction switching means 82.

(effect)
The effect of the electromagnetic actuator 40 of this embodiment is demonstrated contrasting with a comparative example.
(1) In the electromagnetic actuator 40 of the present embodiment, the two permanent magnets 501 and 502 that attract the plungers 651 and 652 in the backward direction are fixed to the holder 45 that is a stationary part so that the directions of the magnetic poles are opposite to each other. Is done. Further, by switching the energization direction of the coil 47, a coil magnetic flux in the opposite direction is generated with respect to one of the two permanent magnets 501 and 502, and the attractive force is reduced. Then, the regulating pins 601 and 602 on the side where the attractive force of the permanent magnets 501 and 502 is reduced are operated in the forward direction by the biasing force of the springs 751 and 752.

  That is, the electromagnetic force generated by the coil 47 is used to reduce the attractive force by the permanent magnets 501 and 502, and is not intended to operate the regulation pins 601 and 602. It is the urging force of the springs 751 and 752 that actuate the restriction pins 601 and 602. Thereby, compared with the structure which drives a control pin directly with the electromagnetic force which a coil produces | generates, the response speed of the control pins 601 and 602 can be improved, without making the coil 47 large.

  (2) The electromagnetic actuator 400 of the comparative example shown in FIG. 15 generates a coil magnetic flux in the reverse direction with respect to the permanent magnet corresponding to the actuating side regulating pin, thereby reducing the attracting force, and the actuating side regulating pin by the biasing force of the spring. The point which advances is common to this embodiment. However, the comparative example does not have the “front suction part” as in the present embodiment, and the holding force that is held at the most advanced position after the operation-side regulating pin moves forward depends only on the spring force. Yes.

FIG. 14A shows the relationship between the stroke and force of the regulation pin in the comparative example. “ ^* ” Added to the end of the symbol means a value of a comparative example. As for the operation of the restriction pin, it is assumed that the energization is stopped as soon as the threshold stroke St is reached after the plunger is pulled away from the permanent magnet by reverse energization. As for the magnet attracting force, only the magnet attracting force Fm0 ^* when not energized is illustrated.
As shown in FIG. 14A, the negative magnet attracting force Fm0 ^* in the backward direction almost disappears in the stroke Sd and gradually approaches 0 in the full stroke Sf. Therefore, “the resultant force Fr ^{* of the} spring force Fsp ^* and the magnet attracting force Fm0 ^* ”, which is a force for urging the regulating pin in the forward direction, also gradually approaches the spring force Fsp ^* in the full stroke Sf.

Here, the negative OFF holding force “−Fh _OFF ” that holds the restriction pin in the last retracted position and the positive ON holding force “Fh _ON ” that holds the restriction pin in the most advanced position are The required value is determined by vibration or other external force assumed in the applied valve lift adjusting device.

Therefore, in the electromagnetic actuator 400 of the comparative example, the lower limit value of the spring force Fsp ^* at the full stroke Sf must be a value equal to or greater than the required value of the on-time holding force “Fh _ON ”. Then, even if the spring constant (inclination in the figure) is set as small as possible, the spring set load J ^* at the zero stroke S0 must be set to a certain value or more.
When the magnet attracting force Fm0 at the zero stroke S0 is -K ^* , the off-time holding force "-Fh _OFF " is represented by (J ^* -K ^* ). Therefore, in order to satisfy the required value of the off-time holding force “−Fh _OFF ”, the absolute value of −K ^* must be set to a certain value or more. Therefore, it is necessary to make the size of the permanent magnet larger than a certain size, and the possibility of downsizing the permanent magnet is limited.

On the other hand, as shown in FIG. 14B, the electromagnetic actuator 40 of the present embodiment is provided with front suction portions 425 and 426 on the bottom wall 422 of the yoke 41, and the stroke Se slightly before the full stroke Sf. Therefore, the positive front suction force Ffr is effectively generated. Accordingly, “the resultant force Fr of the spring force Fsp and the magnet attracting force Fm0” also increases between the stroke Se and the full stroke Sf. Therefore, the spring force Fsp can be made smaller than the spring force Fsp ^* of the comparative example while satisfying the required value of the on-time holding force “Fh _ON ” at the full stroke Sf.

Therefore, the spring set load J at the zero stroke S0 can be made smaller than the spring set load J ^* of the comparative example, and furthermore, the required value of the _OFF holding force “−Fh _OFF ” (= J−K) is satisfied. The absolute value of the magnet attracting force -K at zero stroke S0 can be made smaller than the absolute value of the magnet attracting force -K ^* of the comparative example.

  That is, since the holding force for holding the restriction pin at the most advanced position is obtained by the sum of the spring force Fsp and the front suction force Ffr, the spring force can be reduced by the amount of assist by the front suction force Ffr. Then, it is possible to reduce the magnet attracting force of the permanent magnet that attracts the plunger in the retracting direction when the regulating pin retracts accordingly. Therefore, a permanent magnet can be reduced in size.

(3) In the present embodiment, the cross transmission portion 434 is provided between the first plunger 651 and the second plunger 652 in the radial direction, and in the range from the most retracted position to the most advanced position in the axial direction. The plungers 651 and 652 overlap.
By passing through the cross transmission portion 434, a magnetic path of the shortest distance is formed between the front attracting portion facing the on-side plunger and the off-side permanent magnet. Is effectively transmitted to the department. Therefore, the front suction force Ffr can be generated efficiently.

  (4) In the present embodiment, a switching member 67 is provided which moves in conjunction with one of the plungers 651 and 652 and switches on / off of magnetic flux transmission according to the axial position. When pulling the plungers 651 and 652 away from the permanent magnets 501 and 502, the switching member 67 delivers the coil magnetic fluxes Φsol1 and Φsol2 between the yoke inner cylinder 430 and the plungers 651 and 652, and the attractive force of the permanent magnets 501 and 502 Contributes to a decrease in Further, when the on-side plungers 651 and 652 move forward, the magnetic flux from the plungers 651 and 652 to the yoke inner cylinder 430 is blocked, thereby suppressing magnetic leakage and contributing to the generation of the front attractive force Ffr. To do.

(Other embodiments)
(A) The relationship between the shape of the permanent magnet and the holder, the area of the end surfaces of the permanent magnet and the plunger is not limited to the configuration of the above embodiment. Moreover, it is not necessary to provide an adapter.
(A) In the above embodiment, the provision of the cross transmission portion 434 is advantageous in generating the front suction force. However, when a desired front suction force can be obtained, the cross transmission portion need not be provided.

  (C) In the above embodiment, the switching member 67 is provided to efficiently switch on / off the magnetic flux transmission. However, the switching member need not be provided as long as the coil magnetic flux is sufficiently transmitted to the permanent magnet or the magnetic leakage at the time of generating the front attractive force is not a problem. Further, the specific configuration of the switching member is not limited to that of the above embodiment.

(D) The valve lift adjusting device is not limited to the intake valve, and may adjust the lift amount of the exhaust valve.
(E) The configuration of the cam, slider, etc. of the valve lift adjustment device is not limited to that exemplified in the above embodiment, and any configuration can be used as long as it can be switched by forward and backward movement of the restriction pin of the electromagnetic actuator. Also good.
As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10: Valve lift adjusting device,
11 ... camshaft, 14, 24 ... engagement groove,
21 ... Slider,
40 ... Electromagnetic actuator, 41 ... Yoke,
425, 426 ... front suction part,
434: Cross transmission part, 47: Coil,
501, 502 ... Permanent magnet,
601, 602 ... restriction pin, 641, 642 ... tip portion,
651, 652 ... Plunger, 751, 752 ... Spring,
91, 92 ... intake valves.

Claims (3)

The present invention is applied to a valve lift adjusting device (10) for adjusting the lift amount of an intake valve (91, 92) or an exhaust valve of an internal combustion engine, and rotates with the cam shaft (11) of the valve lift adjusting device with respect to the cam shaft. The engagement groove (14, 24) formed in the slider (21) that is relatively movable in the axial direction has either one of the two restriction pins (601, 602) or the tip (641, 642), the operating side regulating pin is advanced, and the operating side regulating pin is pushed back by the torque of the camshaft when the tip of the operating side regulating pin is separated from the engaging groove. 40)
A first restricting pin (601) and a second restricting pin (602) which are juxtaposed in advance with respect to the engaging groove;
A first plunger (651) formed of a soft magnetic material and having one end connected to the first restricting pin, and a second plunger (652) having one end connected to the second restricting pin When,
The stationary portion stationary with respect to the first plunger and the second plunger is fixed so that the direction of the magnetic pole is parallel to and opposite to the operation direction of the first plunger and the second plunger, A first permanent magnet (501) for attracting one plunger in the backward direction, and a second permanent magnet (502) for attracting the second plunger in the backward direction;
A coil (47) that generates a magnetic flux in the reverse direction with respect to one of the first permanent magnet or the second permanent magnet by switching the energization direction, and reduces the attractive force for attracting the corresponding plunger;
The first restricting pin and the second restricting pin are urged in the forward direction, and the restricting pin on the side where the attracting force of the permanent magnet is reduced by energizing the coil is operated in the forward direction by the urging force. A spring (751) and a second spring (752);
A front attracting portion (425, 426) that is formed of a soft magnetic material, forms a magnetic circuit between the coil, the permanent magnet, and the plunger, and faces the end of the plunger opposite to the permanent magnet. A yoke (41) having,
With
When the restriction pin moves forward, the front suction portion of the yoke sucks the plunger to generate a front suction force that holds the restriction pin at the most advanced position.   In the operation direction of the plunger, one of the plungers in the most retracted position and the other plunger that moves from the most retracted position to the most advanced position overlap, and can transmit magnetic flux between the plungers. The electromagnetic actuator according to claim 1, further comprising a transmission unit (434). A switching member (67) formed of a soft magnetic material, provided between the yoke and the plunger, and advancing in conjunction with either one of the first plunger or the second plunger;
The switching member is
Transmitting magnetic flux between the yoke and the plunger when both the first plunger and the second plunger are in the most retracted position;
The electromagnetic actuator according to claim 1, wherein when the first plunger or the second plunger moves forward, magnetic flux transmission between the yoke and the plunger is interrupted.

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