JP5708591B2 - Electromagnetic actuator - Google Patents

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.

  The present invention was created in view of the above points, and an object of the present invention is to provide an electromagnetic actuator that improves the response speed of a regulation pin in an electromagnetic actuator applied to a valve lift adjustment device for an internal combustion engine. There is.

A first aspect 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 a coil, and is connected to the restriction pin. The two permanent magnets that attract the plunger in the backward direction are fixed to the stationary part so that the magnetic poles are parallel to the plunger operating direction and opposite to each other, and the energization direction of one coil is switched. It reduces the suction force is generated in the opposite direction of the magnetic flux with respect to one of the two permanent magnets by, and, Rukoto increases the suction force to generate magnetic flux in the same direction relative to the other of the two permanent magnets, Then, the regulation pin on the side where the attractive force of the permanent magnet is reduced is operated in the forward direction by the biasing force of the spring.
That is, 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.

Moreover, since the permanent magnet is provided in the stationary part, the permanent magnet can be enlarged and the magnet attracting force can be increased without increasing the weight of the movable part. And according to the increase in magnet attraction force, the urging | biasing force of the spring which tries to separate a plunger from a permanent magnet can be set largely. Therefore, the response speed of the restriction pin can be further improved.
Further, since the permanent magnet is fixed to the stationary portion, the electromagnetic actuator of Patent Document 1 that operates the permanent magnet is prevented from cracking due to an impact at the time of operation, and as a result, the actuator becomes inoperable. be able to.

  In addition, in the electromagnetic actuator of the present invention applied to the valve lift adjusting device, when the tip of the restriction pin is separated from the engagement groove, the restriction pin is pushed back with a sufficiently large force due to the torque of the camshaft. Therefore, since the spring force for moving the restriction pin forward can be set relatively large, the response speed of the restriction pin can be further improved.

  The electromagnetic actuator according to the second aspect of the present invention includes one integrated permanent magnet instead of the first permanent magnet and the second permanent magnet according to the first aspect. The integrated permanent magnet is fixed to the stationary part so that the direction of the magnetic pole is in a direction perpendicular to the operation direction of the plunger. Then, the lateral first magnetic pole as one magnetic pole attracts the first plunger in the backward direction instead of the first permanent magnet, and the lateral second magnetic pole as the other magnetic pole replaces the second permanent magnet with the second plunger. Aspirates backward. Thereby, the number of permanent magnets can be reduced from two to one.

  The electromagnetic actuator of the 3rd mode of the present invention is provided with one regulation pin, a plunger, a permanent magnet, and one spring with respect to the 1st mode. The direction of the magnetic pole of the permanent magnet is fixed so as to be parallel to the operation direction of the plunger. The coil generates a magnetic flux in the reverse direction with respect to the permanent magnet, and reduces the attractive force for attracting the plunger. Thus, even if it is an aspect provided with one control pin, the effect similar to the 1st aspect of this invention is acquired.

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 a first 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 a 1st 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 the valve lift adjusting device to which the electromagnetic actuator according to the first 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 1st Embodiment of this invention. It is the VIII-VIII sectional view taken on the line of FIG. It is the IX-IX 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 1st Embodiment of this invention. It is sectional drawing at the time of the 2nd direction electricity supply of the electromagnetic actuator by 1st Embodiment of this invention. It is a principal part expanded sectional view of the electromagnetic actuator by 1st Embodiment of this invention. In the electromagnetic actuator by 1st Embodiment of this invention, it is a characteristic view which shows the change of the magnet attraction force by electricity supply. It is sectional drawing at the time of the 1st direction electricity supply of the electromagnetic actuator by 2nd Embodiment of this invention. It is the XV-XV sectional view taken on the line of FIG. It is a principal part expanded sectional view of the electromagnetic actuator by 2nd Embodiment of this invention. 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 a third embodiment of the present invention is applied. It is a figure when it starts to transfer from a large lift state to a small lift state in a valve lift adjusting device to which an electromagnetic actuator according to a third embodiment of the present invention is applied. It is sectional drawing at the time of the deenergization of the electromagnetic actuator by 3rd Embodiment of this invention. It is the XX-XX sectional view taken on the line of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The electromagnetic actuator according to the first embodiment of the present invention is applied to a valve lift adjusting device that adjusts the 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”. 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 shaft 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 10 to 12, and “reverse direction” or “rearward” is the upper side of FIGS. 7 and 10 to 12. Corresponds to the direction. The direction in which the regulation pins 601 and 602 advance and retreat is referred to as the “axial direction” of the electromagnetic actuator 40, and the direction orthogonal to the axial direction of the electromagnetic actuator 40 is referred to as “radial direction”.

Further, the electromagnetic actuator 40 includes a yoke 41, a holder 45, 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 45, 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 9, 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. As shown in FIG. 9, the inner cylinder portion 43 of the yoke 41 is formed with two plunger holes 431 and 432 sandwiching the partition wall 433.

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. As shown in FIGS. 8 and 9, 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. In other words, the minimum width of the partition 453 of the holder 45 is set to be equal to the minimum width of the partition 433 of the yoke inner cylinder portion 43.

  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, the area Am of the end face 53 of the permanent magnets 501 and 502 is larger than the area Ap of the end face 66 of the plungers 651 and 652. Correspondingly, in the adapters 551 and 552, the area of the end face 56 on the permanent magnet side conforms to the area Am of the end face 53 of the permanent magnets 501 and 502, and the area of the end face 58 on the plunger side is the same as that of the end face 66 of the plungers 651 and 652. 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 walls 57 of the adapters 551 and 552 are formed with inclined surfaces on the sides separated from each other, and formed with surfaces parallel to the pin axes O1 and O2 on the sides close to each other. That is, the adapters 551 and 552 are 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 and is connected to the connecting portion 621 of the first restriction pin 601. The first plunger 651 is guided in the first plunger hole 431 of the yoke inner cylinder portion 43 and moves forward and backward integrally with the first restriction pin 601.
Here, at the last retracted position of the first plunger 651, the outer wall of the first plunger 651 and the inner wall of the first plunger hole 431 of the yoke inner cylinder portion 43 are at least one in the axial direction, that is, the operating direction of the first plunger 651. The parts overlap. This overlap portion constitutes a magnetic flux transmission path from the yoke 41 to the first plunger 651.
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.

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, 10, 11, and 13.
(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 acts in the direction in which the first plunger 651 is retracted, and decreases as the stroke increases. The spring force Fsp acts in the direction in which the first plunger 651 moves forward and decreases linearly as the stroke increases. Since 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.

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. 10, when a current in the first direction is supplied to the coil 47, the coil 47 generates a coil magnetic flux Φsol 1 that is opposite to the magnetic flux Φm 1 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, since the inner wall of the first plunger hole 431 of the yoke inner cylinder portion 43 and the outer wall of the first plunger 651 overlap in the axial direction, the coil magnetic flux Φsol1 is transmitted via this overlap portion. The 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, even if the magnet attracting force Fm− during reverse energization exceeds the spring force Fsp at the permanent magnet end surface 53, the adapter end surface corresponding to the position of the plunger end surface 66 at the zero stroke S0. 58 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 magnet attracting force Fm− is less than the spring force Fsp at the zero stroke S0 due to the coil magnetic flux in the reverse direction.

As a result, since the magnet attracting force Fm− at the zero stroke S0 is smaller than the spring force Fsp, the first restricting pin 601 moves forward by the force obtained by subtracting the magnet attracting force Fm− from the spring force Fsp of the first spring 751. . And even if it stops energizing after exceeding threshold stroke St in which magnet attractive force Fm0 and spring force Fsp become equal, the 1st regulation pin 601 will reach to full stroke Sf by spring force Fsp. That is, when energizing in the first direction, the first restriction pin 601 operates as an “operation side restriction pin”.
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 by the rotation of the switching unit 20, whereby the first plunger 651 moves backward from the full stroke Sf to a stroke region less than the threshold stroke St. Since 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, for the second permanent magnet 502 when energized in the first direction, 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 through the second permanent magnet 502 is superimposed by the coil magnetic flux Φsol1 generated by energization in the same direction, the magnet attractive 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. 11, 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, at the time of energization in the second direction, the second permanent magnet 502 is demagnetized contrary to at the time of energization in the first direction, and the magnet attracting force Fm0 that attracts the second plunger 652 is decreased. The second restriction pin 602 operates as an “operation-side restriction pin” by the spring force Fsp of the second spring 752.

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 will be described.
(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) Since the permanent magnets 501 and 502 are provided in the stationary part, the permanent magnets 501 and 502 can be enlarged and the magnet attracting force can be increased without increasing the weight of the movable part. And according to the increase in magnet attraction force, the urging force of the springs 751 and 752 for pulling the plunger away from the permanent magnets 501 and 502 can be set large. Therefore, the response speed of the restriction pins 601 and 602 can be further improved.
(3) Since the permanent magnets 501 and 502 are fixed to the stationary part, the permanent magnet is broken by an impact at the time of operation with respect to a conventional electromagnetic actuator that operates the permanent magnet, and as a result, the actuator becomes inoperable. Can be prevented.

(4) The area Am of the end face 53 of the permanent magnets 501 and 502 is formed larger than the area Ap of the end face 66 of the opposing plungers 651 and 652. Then, adapters 551 and 552 made of a soft magnetic material are provided at the end portions of the permanent magnets 501 and 502 on the plungers 651 and 652 side. The adapters 551 and 552 function as magnetic flux collecting members that gradually reduce the cross-sectional area from the end surface 56 on the permanent magnet side toward the end surface 58 on the plunger side and collect the magnetic flux of the permanent magnets 501 and 502 on the plungers 651 and 652.
This makes it possible to efficiently collect more magnetic flux from the permanent magnets 501 and 502 having a relatively large cross-sectional area while relatively reducing the cross-sectional area of the plungers 651 and 652 and reducing the weight of the movable part. it can. Therefore, the magnet attractive force acting on the plungers 651 and 652 can be increased.

  (5) By providing the adapters 551 and 552 between the permanent magnets 501 and 502 and the plungers 651 and 652, an amount corresponding to the thickness Ta of the adapters 551 and 552 is provided on the adapter end surface 58 with respect to the permanent magnet end surface 53. Magnet attracting force Fm decreases. Accordingly, it is advantageous for generating a reverse coil magnetic flux so that the magnet attracting force Fm− is less than the spring force Fsp at the zero stroke S0 during reverse energization. Therefore, the plungers 651 and 652 can be separated from the magnet attracting force with a smaller current than in the case where the adapters 551 and 552 are not provided.

  (6) By providing the adapters 551 and 552 between the permanent magnets 501 and 502 and the plungers 651 and 652, the impact when the plungers 651 and 652 are attracted to the permanent magnets 501 and 502 can be reduced. Therefore, it is possible to prevent the permanent magnet from being broken by an impact during operation, and as a result, the actuator cannot be operated.

  (7) The yoke inner cylinder portion 43 is provided so that the inner walls of the plunger holes 431 and 432 overlap the outer walls of the plungers 651 and 652 in the axial direction at the last retracted position of the plungers 651 and 652. This secures a magnetic flux transmission path from the yoke 41 to the plungers 651 and 652, which is advantageous when the plungers 651 and 652 are separated from the magnet attracting force by the coil magnetic flux in the reverse direction.

  (8) In the electromagnetic actuator 40 of this embodiment applied to the valve lift adjusting device 10, when the tip portions 641 and 642 of the regulation pins 601 and 602 are separated from the engagement grooves 14 and 24, the torque of the camshaft 11 is used. The restriction pins 601 and 602 are pushed back with a sufficiently large force. Therefore, since the urging force of the springs 751 and 752 that advance the restriction pins 601 and 602 can be set relatively large, the response speed of the restriction pins 601 and 602 can be further improved.

(Second Embodiment)
Next, the electromagnetic actuator of 2nd Embodiment of this invention is demonstrated with reference to FIGS. In the following description of the embodiment, the same reference numerals are given to substantially the same components as those in the first embodiment, and the description will be omitted.
As shown in FIGS. 14 and 15, the electromagnetic actuator 405 of the second embodiment is different from the electromagnetic actuator 40 of the first embodiment in the configuration of the integrated permanent magnet 54, the adapters 555 and 556, and the holder 85. The configuration of is the same. The integrated permanent magnet 54, the adapters 555 and 556, and the holder 85 are formed symmetrically with respect to the virtual plane V including the pin axis O1 and the pin axis O2.

  The integrated permanent magnet 54 is a column having an oval cross-sectional shape, and is fixed to a holder 85, which is a stationary part, so that the direction of the magnetic pole is perpendicular to the operating direction of the plungers 651 and 652. Here, the magnetic pole on the first plunger 651 side is referred to as “lateral first magnetic pole 541”, and the magnetic pole on the second plunger 652 side is referred to as “lateral second magnetic pole 542”. In the present embodiment, the lateral first magnetic pole 541 is an N pole, and the lateral second magnetic pole 542 is an S pole.

  When the coil 47 is not energized, the lateral first magnetic pole 541 of the integrated permanent magnet 54 attracts the first plunger 651 in the backward direction instead of the first permanent magnet 501 of the first embodiment. Further, the lateral second magnetic pole 542 of the integrated permanent magnet 54 attracts the second plunger 651 in the backward direction instead of the second permanent magnet 502 of the first embodiment. As described above, the integrated permanent magnet 54 can be considered as a function in which the functions of the first permanent magnet 501 and the second permanent magnet 502 of the first embodiment are integrated into one permanent magnet. Call.

  The adapters 555 and 556 are soft magnetic materials such as iron, and the cross-sectional shape along the virtual plane V is formed in an L shape. That is, the adapters 555 and 556 are composed of a base portion 580 provided at the end of the integrated permanent magnet 54 on the plungers 651 and 652 side, and a side wall portion 59 provided outside the outer wall 544 of the integrated permanent magnet 54. . The rear end surface 56 of the base portion 580 is in contact with the front end surface 545 of the integrated permanent magnet 54 or is in close proximity via a minute gap. In addition, the end face 58 of the rear of the plungers 651 and 652 is in contact with the end face 58 of the front of the base portion 580 when not energized.

The adapters 555 and 556 receive the magnetic flux facing the lateral first magnetic pole 541 and the lateral second magnetic pole 542 of the integrated permanent magnet 54 in a wide area of the front end surface 545 and the outer wall 544, and pass through the front end surface 58. To the plungers 651 and 652.
Note that at least a part of the outer walls of the plungers 651 and 652 and the inner walls of the plunger holes 431 and 432 of the yoke inner cylindrical portion 43 overlap in the axial direction at the last retracted position of the plungers 651 and 652. This is the same as the embodiment.

The holder 85 is formed of a nonmagnetic material. In the holder 45 of the first embodiment, the housing portions 451 and 452 that house the permanent magnets 501 and 502 are formed so as to penetrate in the axial direction, whereas the holder 85 of the second embodiment has the integrated permanent magnet 54. , And an accommodating portion 850 that accommodates the adapters 555 and 556 is formed to open to the plungers 651 and 652 side.
The holder 85 has a rear wall 853 formed between the axially rear stator 44 and a circumferential wall 854 formed between the holder 85 and the bobbin 46 in the radial direction. The rear wall 853 covers the rear end surface 543 of the integrated permanent magnet 54. The peripheral wall 854 covers the side wall 59 of the adapters 555 and 556 in the magnetic pole direction of the integrated permanent magnet 54, and covers the outer wall 544 of the integrated permanent magnet 54 in a direction orthogonal to the magnetic pole direction of the integrated permanent magnet 54.

Next, the operation of the electromagnetic actuator 405 according to the second embodiment having the above-described configuration will be described with reference to FIG. 14 with particular attention to differences from the first embodiment.
In the electromagnetic actuator 40 according to the first embodiment, a magnetic flux flows between the first permanent magnet 501 and the second permanent magnet 502 via the stator 44, and there is a possibility of becoming “leakage magnetic flux” that is not used effectively. On the other hand, in the electromagnetic actuator 405 of the second embodiment, the rear end surface 543 of the integrated permanent magnet 54 is covered with the rear wall 853 of the non-magnetic holder 85. Therefore, the magnetic flux Φms flowing between the lateral first magnetic pole 541 and the lateral second magnetic pole 542 via the stator 44 is limited as indicated by a broken line arrow in the figure. Therefore, the leakage magnetic flux from the integrated permanent magnet 54 to the stator 44 can be reduced.

  On the other hand, side wall portions 59 of the magnetic adapters 555 and 556 are provided on the outer diameter side of the outer wall 544 of the first horizontal magnetic pole 541 and the second horizontal magnetic pole 542, and a non-magnetic material is provided on the outer diameter side of the side wall portion 59. A peripheral wall 854 of the holder 85 is provided. Therefore, the radially outward magnetic flux Φmp from the lateral first magnetic pole 541 (or the lateral second magnetic pole 542) is bent downward in the figure, and as indicated by solid line arrows in the figure, the plungers 651 and 652 and the yoke inner cylinder part. The horizontal second magnetic pole 542 (or the horizontal first magnetic pole 541) is reached via 43.

  As described above, the action of the holder 85 and the adapters 555 and 556 preferentially generates the magnetic flux Φmp passing through the plungers 651 and 652 between the lateral first magnetic pole 541 and the lateral second magnetic pole 542, and the stator 44. The magnetic flux Φms passing through is limited. As a result, in the present embodiment, a downward magnetic flux Φm1 is generated in the first plunger 651, and an upward magnetic flux Φm2 is generated in the second plunger 652.

  Thus, similarly to the effect (1) of the first embodiment, the coil 47 in the reverse direction with respect to one of the horizontal first magnetic pole 541 and the horizontal second magnetic pole 542 of the integrated permanent magnet 54 is switched by switching the energization direction of the coil 47. Generates magnetic flux and reduces the attractive force. Then, the regulating pins 601 and 602 on the side where the attracting force of the magnetic poles 541 and 542 is reduced are operated in the forward direction by the urging force of the springs 751 and 752, so that the regulating pins 601 and 602 are not enlarged. It is possible to improve the response speed.

  Similarly to the effects (4) and (6) of the first embodiment, the adapters 555 and 556 use the magnetic flux of the horizontal first magnetic pole 541 and the horizontal second magnetic pole 542 of the integrated permanent magnet 54 as the magnetic flux collecting members as the plunger 651. In addition to being collected in 652, the impact when the plungers 651 and 652 are attracted to the integrated permanent magnet 54 as buffer members can be reduced. Further, the effects (2), (3), (5), (7), and (8) of the first embodiment are similarly achieved.

  In addition, in the first embodiment, the magnetic pole on the stator 44 side cannot be used sufficiently effectively in terms of generation of an attractive force while using the two permanent magnets 501 and 502. On the other hand, in the second embodiment, both magnetic poles 541 and 542 of one integrated permanent magnet 54 can be effectively used for attraction. Thereby, in the second embodiment, the number of permanent magnets can be reduced from two to one while maintaining the same magnet attractive force as in the first embodiment.

(Third embodiment)
Next, an electromagnetic actuator according to a third embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 17 and 18, the valve lift adjusting device 107 to which the electromagnetic actuators 407 and 408 of the third embodiment are applied is different from the valve lift adjusting device 10 described in the first embodiment with one switching unit. Instead of 20, switching sections 13 and 23 divided into two are provided. A first engagement groove 14 and a second engagement groove 24 are formed in the first switching unit 13 and the second switching unit 23, respectively.

  The electromagnetic actuators 407 and 408 have the same configuration with one regulating pin 607 and 608, respectively. As shown in FIG. 17, the electromagnetic actuator 407 corresponding to the first switching unit 13 advances the restriction pin 607 in synchronization with the rotation timing of the camshaft 11 and engages the first engagement groove 14. As shown in FIG. 18, the electromagnetic actuator 408 corresponding to the second switching unit 23 advances the restriction pin 608 in synchronization with the rotation timing of the camshaft 11 and engages the second engagement groove 24.

The action of the valve lift adjusting device 107 when the restricting pins 607 and 608 engage with the engaging grooves 14 and 24 is the same as that of the first embodiment.
In the third embodiment, two “1-pin type” electromagnetic actuators 407 and 408 are interlocked to operate the regulating pins 607 and 608 alternately, whereby the “2-pin type” first and second embodiments are performed. The electromagnetic actuators 40 and 405 operate in the same manner.

Next, the configuration of the electromagnetic actuator 407 of the third embodiment will be described with reference to FIGS. 19 and 20, particularly focusing on the differences from the first embodiment.
As shown in FIGS. 19 and 20, in the electromagnetic actuator 407, the restriction pin 607, the plunger 657, the bush 737, and the spring 757 arranged on the pin axis O7 are exactly the same as those in the first embodiment. The yoke 417, the bobbin 467, the stator 447, the holder 457, the coil 477, and the sleeve 707 are functionally the same as those of the first embodiment, except that the cross-sectional shape is a circle centered on the pin axis O7. It is equivalent. The plunger 651 at least partially overlaps the inner wall of the plunger hole 439 of the yoke inner cylinder portion 437 in the axial direction at the most retracted position.

  The permanent magnet 507 differs from the first embodiment in that the permanent magnet 507 is not eccentric with respect to the plunger 657 and is accommodated in the accommodating portion 459 of the holder 457 coaxially with the pin axis O7. Correspondingly, the adapter 557 is not in the shape of a truncated cone but in the shape of a truncated cone that is uniform in each direction.

  Further, the end surface 53 of the permanent magnet 507 and the end surface 66 of the plunger 657 facing each other are formed such that the area of the end surface 53 of the permanent magnet 507 is larger than the area of the end surface 66 of the plunger 657. In the adapter 557, the area of the end surface 56 on the permanent magnet side conforms to the area of the end surface 53 of the permanent magnet 507, and the area of the end surface 58 on the plunger side conforms to the area of the end surface 66 of the plunger 657. Therefore, the adapter 557 has a cross-sectional area that gradually decreases from the end surface 56 on the permanent magnet side toward the end surface 58 on the plunger side, and functions as a magnetism collecting member. Further, the adapter 57 also functions as a buffer member when the plunger 657 is attracted to the permanent magnet 507. These points are the same as in the first embodiment.

The direction of the magnetic pole of the permanent magnet 507 is parallel to the operation direction of the plunger 657, and the direction of the magnetic flux of the permanent magnet 507 is opposite to the direction of the coil magnetic flux generated by energization in one direction from the power source 81 to the coil 477. In this case, the energization direction switching means 82 of the first embodiment is not necessary.
In 3rd Embodiment, there exists an effect (1)-(8) similar to 1st Embodiment.

(Other embodiments)
(A) In the first embodiment, the area Am of the end face 53 of the permanent magnets 501 and 502 is set larger than the area Ap of the end face 66 of the opposing plungers 651 and 652. However, when the magnetic flux transmitted from the permanent magnet to the plunger is sufficiently secured, the area of the end face of the permanent magnet may be set equal to or less than the area of the end face of the opposing plunger. The same applies to the third embodiment.
In this case, the adapter may be formed in a cylindrical shape having a constant cross section as a buffer member that relieves the impact on the permanent magnet when the plunger is retracted, not as a magnetic flux collecting member.
Alternatively, for example, when a stopper for retracting the plunger is provided in another part such as between the regulation pin and the sleeve, the adapter as the buffer member may not be provided.

(A) The cross-sectional shape of the permanent magnets of the first and third embodiments is not limited to a circle, but may be a semicircle or a polygon. Further, the cross-sectional shapes of the yoke and the holder are not limited to the shapes of the above embodiments. Alternatively, the yoke and the holder are not necessarily provided.
(C) In the above embodiment, the magnetic flux is transmitted by overlapping the inner walls of the plunger holes 431 and 432 of the yoke inner cylinder portion 43 and the outer walls of the plungers 651 and 652 in the axial direction at the last retracted position of the plungers 651 and 652. A route is secured. However, when the magnetic flux transmission path is secured elsewhere, the yoke and the plunger need not overlap in the axial direction.

(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, 47: Coil,
501, 502 ... Permanent magnet,
551, 552... Adapter (magnet collecting member, buffer member),
601, 602 ... restriction pin, 641, 642 ... tip portion,
651, 652 ... Plunger,
751, 752... Springs,
91, 92 ... intake valves.

Claims (4)

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;
By switching the energization direction, a magnetic flux in the opposite direction is generated with respect to one of the first permanent magnet or the second permanent magnet, the attracting force for attracting the corresponding plunger is reduced , and the first permanent magnet to generate a magnetic flux in the same direction relative to the other magnet or the second permanent magnets, a corresponding one of the coils Ru increases the suction force for attracting the plunger (47),
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);
An electromagnetic actuator comprising: The permanent magnet has a large area of end faces facing each other with respect to the corresponding plunger,
The magnetism collecting member (551, 552) formed of a soft magnetic material and collecting magnetic flux of the permanent magnet on the plunger is provided at an end of the permanent magnet on the plunger side. Electromagnetic actuator.   The end of the permanent magnet on the plunger side is provided with a buffer member (551, 552) that is formed of a soft magnetic material and reduces the impact on the permanent magnet when the plunger is attracted to the permanent magnet. The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is characterized in that In both the reverse direction energization when the magnetic flux generated by the coil is opposite to the magnetic flux of the permanent magnet and the same direction energization when the energization is in the same direction,
The attraction force acting on the plunger by the magnetic flux of the permanent magnet and the coil is 0 at the full stroke position at which the plunger is farthest from the permanent magnet. The electromagnetic actuator described in 1.

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