JP2002115516A - Electromagnetically driving device of engine valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a hammering sound and abrasion by restraining sudden operation at opening-closing time of an engine valve. SOLUTION: A casing 29 for housing an armature 30, electromagnets 31 and 32 for an opening-closing valve and a valve opening side spring 33 inside is fixed to an upper surface of a cylinder head 21 for slidingly holding an intake valve 23. A valve closing side spring 28 is elastically installed the casing and a bottom surface of a holding hole 27. A rocking cam 46 having vertically first and second cam surfaces 50 and 51 abutting to first and second follower surfaces 45a and 45b is rockingly arranged inside a follower member 45 arranged on an armature rod 38, and an energizing means 47 is arranged in a casing body 29a for applying more effective braking force of the armature rod by elastically contacting a plunger 55 with the upper and lower sides of an outside surface 52 of the rocking cam during rocking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic drive device for mainly opening and closing an engine valve such as an intake valve or an exhaust valve of an internal combustion engine for an automobile mainly by electromagnetic force.

[0002]

2. Description of the Related Art Conventional electromagnetic drive devices of this type include:
For example, those described in JP-A-8-21220 are known.

Referring to FIG. 12, an intake valve 2 slidably provided on a cylinder head 1 of an engine is described.
And an electromagnetic drive mechanism 3 for opening and closing the intake valve 2.

The intake valve 2 has an umbrella portion 2a for opening and closing the open end of the intake port 4, and a valve stem 2b integrally provided at the upper end of the umbrella portion 2a.

The electromagnetic drive mechanism 3 includes a cylinder head 1
A disk-shaped armature 6 is fixed to the upper end of the valve stem 2b inserted into the casing 5 fixed above, and the armature 6 is sucked into the upper and lower positions inside the casing 5 so that the intake valve 2 is moved. A valve closing electromagnet 7 and a valve opening electromagnet 8 to be opened and closed are arranged.

Between the upper wall of the casing 5 and the upper surface of the armature 6, a valve-opening side spring 9 for urging the intake valve 2 in the opening direction is resiliently held, while a seat groove on the upper surface of the cylinder head 1 is provided. Between the bottom surface and the lower surface of the armature 6,
A valve-closing spring 10 for urging the intake valve 2 in the closing direction is elastically held. Further, in each of the electromagnets 7 and 8, a control current from the electronic control unit 12 is output to each coil via the amplifier 11.

[0007] The electronic control unit 12 controls the energization amount of the two electromagnets 7 and 8 based on the detection signals from the engine speed sensor 13 and the temperature detection sensor 14 of the valve closing electromagnet 7. In the figure, reference numeral 15 denotes a power supply.

The spring force of the two springs 9 and 10 and the attraction force of the two electromagnets 7 and 8 provide
The intake valves 2 are stored and retained as potential energy by the springs 9 and 10 and the opening and closing of the electromagnetic force are alternately repeated to open and close the intake valve 2.

[0009]

However, in the above-mentioned conventional electromagnetic drive device, when the intake valve 2 is opened and closed, the electromagnetic attraction force of each of the electromagnets 7, 8 is applied to each of the springs 9, 10 which oppose the attraction force. When the valve is closed, the umbrella portion 2a collides violently with the valve seat 4a.
When the valve is opened, the armature 6 may collide with the valve opening electromagnet 8.

That is, the principle of increasing the attraction force of each of the electromagnets 7 and 8 will be described with reference to FIGS. 13A and 13B.
Electromagnetic attractive force characteristics and springs 9 and 10 when opening and closing intake valve 2
The armature 6 is firstly attracted upward by the attraction force of the valve-closing electromagnet 7 when the valve is closed. Therefore, when the intake valve 2 slides upward, the valve-closing-side spring 10 is extended, while the valve-opening-side spring 9 is compressed, so that the spring force increases and the spring force is stored.

Next, when the valve is opened, the valve closing electromagnet 7 is
While an F signal (non-energizing signal) is output, an ON signal (energizing signal) is output to the valve opening electromagnet 8 and the armature 6
Is sucked downward, and the intake valve 2 slides downward, the valve-opening-side spring 9 is extended, while the valve-closing-side spring 1 is extended.
0 is compressed, the spring force increases, and the spring force is stored.

Therefore, when the valve is closed and the valve is opened, the sliding speed of the intake valve 2 is reduced by the increased spring force of the coil springs 9 and 10 on the valve opening side and the valve closing side. At times, the attraction force of the electromagnets 7, 8 on the attraction side suddenly increases in addition to the compressed and extended spring reaction force. That is, the electromagnetic attraction force of each of the electromagnets 7 and 8 is
And the fixed cores 7a, 8a of the electromagnets 7, 8 increase in inverse proportion to the square of the distance. Therefore, the increased suction force overcomes the combined spring force of the springs 9 and 10 on the compression and extension sides and causes the armature 6 to move rapidly upward or downward without sufficiently decelerating.

Therefore, as shown in FIG. 13A, the intake valve 2 suddenly changes its lift and down when it is fully opened and when it is closed. As a result, the umbrella portion 2a collides with the valve seat 4a when it is closed, and the armature when it is opened. 6 may collide with the valve-opening electromagnet 8 to generate loud tapping noise, and may cause wear and breakage of the armature 6 and the valve seat 4a.

[0014]

SUMMARY OF THE INVENTION The present invention has been devised in view of the problems of the above-mentioned conventional apparatus, and the invention according to claim 1 has an armature linked to an engine valve and an armature which sucks the armature. An opening and closing electromagnet for opening and closing the engine valve, a spring member for urging the engine valve in a closing direction and an opening direction to hold the engine valve in a neutral position, and an opening and closing speed of the engine valve An electromagnetic drive device for an engine valve having a braking mechanism for braking the armature, wherein the braking mechanism is linked to the armature and has a follower member having a pair of follower surfaces, and each of the followers moves up and down as the armature moves up and down. A swinging cam having a pair of cam surfaces for rolling the surface to brake the opening and closing speed in the terminal region of the opening and closing operation of the engine valve, and a predetermined position on an outer surface formed between the two cam surfaces of the swinging cam. Elastic contact and pivot of swing cam It is characterized by comprising biasing means for biasing the substantially neutral position toward the.

Therefore, according to the present invention, when the armature is attracted by the valve-opening electromagnet at the time of starting the engine, and is lowered by the spring force of the valve-opening-side spring member, the follower member presses the swing cam downward. While the first ramp portion of one cam surface is in rolling contact with the first follower surface, the first lift portion of the first cam surface presses, for example, a valve stem of an intake valve to lower, that is, open.

On the other hand, when the intake valve is closed, the valve-opening electromagnet is de-energized, the valve-closing electromagnet is energized, the armature is attracted to the valve-closing electromagnet, and the intake valve is also closed by the valve-closing-side spring member. It rises in the valve closing direction.

At the time of the opening / closing operation of the intake valve,
As the follower member moves up and down, each cam surface of the oscillating cam rolls on the opposing follower surface, and in the terminal region of the opening and closing operation of the intake valve, the contact position of one cam surface against one follower surface. Is rotated from the base portion side of the ramp portion to the lift portion side, the contact position of the other cam surface with respect to the other follower surface shifts from the lift portion side of the ramp portion to the base portion side. Therefore, the moment about the rotation center of the swing cam, which is generated by transmitting the spring force of the on-off valve spring member to the swing cam via the valve stem, approaches zero. Therefore, the swing cam gradually stops at a reduced rotation speed. With this, the armature will have its speed as small as possible at the end of its stroke,
The intake valve can also prevent the generation of loud collision noise at the stroke end.

In addition, when the swing cam rotates to the maximum in the vertical direction in the end region of the opening / closing operation of the intake valve, the urging means presses the upper or lower side of the outer surface of the swing cam to swing. The moving cam is urged to return to the neutral position. For this reason,
A strong return torque can be applied near the maximum swing of the swing cam, whereby a more effective braking action of the intake valve can be obtained.

According to a second aspect of the present invention, the urging means includes a plunger provided in a casing containing the armature or the electromagnet so as to be able to advance and retreat in the direction of the outer surface of the swing cam, and And a spring member that urges in the lateral direction.

According to a third aspect of the present invention, a gap is formed between the outer surface and the tip end edge of the plunger at a neutral position in the rotation direction of the swing cam.

According to a fourth aspect of the present invention, there is provided an armature linked to an engine valve via an armature rod, and an electromagnet for opening and closing the valve which sucks the armature to open and close the engine valve. An electromagnetic drive device for an engine valve, comprising: a spring member that urges the engine valve in a closing direction and an opening direction to hold the engine valve at a neutral position; and a braking mechanism that brakes the opening and closing speed of the engine valve. The braking mechanism includes a cam provided on an outer surface of the armature rod, the cam having a substantially U-shaped cam surface along the axial direction of the armature rod, and the cam having a distal end portion which is moved along with the stroke of the armature rod. Braking means for elastically contacting the surface to brake the opening / closing speed in the terminal region of the opening / closing operation of the engine valve.

According to a fifth aspect of the present invention, the brake means includes a plunger provided in a casing containing the armature or the electromagnet so as to be able to advance and retreat in the direction of the cam surface.
A spring member for urging the plunger in the outer surface direction.

The invention according to claim 6 is characterized in that a roller that rolls on the cam surface is provided at the tip of the plunger.

According to a seventh aspect of the present invention, a gap is formed between the cam surface and the tip of the plunger or the roller at a neutral position in the vertical direction of the armature.

According to an eighth aspect of the present invention, a support means for supporting a radial pressing force on the armature rod from the brake means is provided at a position substantially opposite to the brake means with the armature rod interposed therebetween. It is characterized by:

According to a ninth aspect of the present invention, the support means supports an armature rod facing the braking means.

[0027]

FIG. 1 shows a first embodiment in which an electromagnetic drive device for an engine valve according to the present invention is applied to an intake side, and an opening end of an intake port 22 formed in a cylinder head 21 is opened and closed. An intake valve 23, an electromagnetic drive mechanism 24 for opening and closing the intake valve 23, and a braking mechanism 25 interposed between the intake valve 23 and the electromagnetic drive mechanism 24 are provided.

The intake valve 23 is provided with an umbrella portion 23a which is attached to and detached from an annular valve seat 22a attached to an open end of the intake port 22 facing the combustion chamber to open and close the open end.
A valve stem 2 which is integrally provided at the center of the upper surface of 3a and slides in the cylinder head 21 via a valve guide 26.
3b. The intake valve 23 has a spring elastically mounted between a retainer 23e provided on an outer periphery of a cotter 23c fixed to a stem end 23d of a valve stem 23b and a bottom surface of a holding hole 27 formed in the cylinder head 21. It is urged in the closing direction by the spring force of the valve-closing spring 28 which is a member.

The electromagnetic drive mechanism 24 includes a casing 29 provided on the cylinder head 21 and the casing 2.
Disc-shaped armature 3 housed vertically in 9
0, the upper valve-closing electromagnet 31 and the lower valve-opening electromagnet 32 fixed at the vertical position sandwiching the armature 30 in the casing 29, and the intake valve 23 in the opening direction via the armature 30 and the like. And a valve-opening side spring 33 which is a biasing spring member.

As shown in FIG. 1, the casing 29 has a metal main body 29a fixed on the cylinder head 21 with four screws 34 and a screw 35 fixed to one upper end of the main body 29a. The cover 29b is made of a non-magnetic material, and a cylindrical holder 36 made of a non-magnetic material is arranged on the inner peripheral surface on the cover 29 side. The cylindrical holder 36
Has a stepped-diameter nonmagnetic material lid 37 holding the valve-closing electromagnet 31 at the upper end of the opening, and integrally has a bottom wall 36a holding the valve-opening electromagnet 32 at the lower end. ing. In the center of the lid 37, an air vent hole 37a is provided.
Are formed through.

The armature 30 has upper and lower surfaces opposed to the electromagnets 31 and 32, and an upper end 38 a of an armature rod 38 extending downward is fixed at a center to a nut, and a lower end of the armature rod 38 is fixed. A follower member 45 described later of the braking mechanism 25 is integrally provided in the portion. The armature rod 38 is attached to the bottom wall 3.
6a is supported slidably up and down through a cylindrical guide portion 39 fitted and fixed in a cylindrical wall 36b provided at the center of the intake valve 23, and its axis X is the axis Y of the valve stem 23b of the intake valve 23. The lower end of the lower end 38b abuts the stem end 23d.

The electromagnets 31 and 32 for the on-off valves have fixed cores 31a and 32a formed to have a substantially U-shaped cross section, and are opposed to each other with a predetermined gap S via an armature 30. Electromagnetic coils 31b and 32b are wound inside. This electromagnetic coil 31
An energization / non-energization signal from an electronic control unit 40 described later is output to b and 32b so that the armature 30 is suctioned upward or downward or the suction is released.

The valve-opening spring 33 is elastically mounted between the center of the upper surface of the armature 30 and the lower surface of the lid 37. When the spring force of each of the electromagnets 31 and 32 is demagnetized, the valve-opening spring 33 is turned on. The armature 30 is held at a substantially neutral position between the two electromagnets 31 and 32 in balance with the spring force of the electromagnets 31 and 32. In this state, the intake valve 23 is set at a substantially intermediate position between the valve closing position and the maximum valve opening position. Will be retained.

The electronic control unit 40 includes an engine crank angle sensor 41, an engine speed sensor 42, a temperature detection sensor 43 for detecting the temperature of the valve closing electromagnet 31, and an air flow meter 44 for detecting the engine load. Based on the detected value, the valve closing and valve opening electromagnets 31 and 32 are energized.
Non-energization is output relatively repeatedly.

The rotation angle detection value from the crank angle sensor 42 is used for synchronously controlling the opening / closing timing of the intake valve 23 with the rotation of the crankshaft. In other words, the detected value of the rotation speed of the crankshaft is used to cope with the permissible suction time of each of the electromagnets 31 and 32 that changes according to the rotation speed. This is for coping with an increase in the energization resistance of the electromagnetic coil 31b of the electromagnet 31. The detected engine load value by the air flow meter 44 is used together with the detected engine speed value to optimally control the opening / closing timing of the intake valve 23.

The braking mechanism 25 is provided at the lower end 3 of the armature rod 38, as shown in FIGS.
8b, a follower member 45 provided integrally with the shaft 8b, one swing cam 46 rotatably held inside the follower member 45, and a torque for returning the rotation of the swing cam 46 to the neutral position. And an urging means 47 for giving the following.

The follower member 45 is formed in a substantially U-shape in front, and the lower surface of the upper end wall and the flat upper surface of the lower end wall which are opposed to each other have a first follower surface 45a and a second follower surface 45, respectively.
b.

As shown in FIG. 2, the swing cam 46 is rotatably supported via a central hole 46a on a cam support shaft 49 fixedly penetrated between opposed bosses 48a and 48b projecting from the inner surface of the main body 29a. Have been. The swing cam 46
Is formed in a substantially fan shape as shown in FIG.
A substantially flat outer surface 52 is provided on the opposite side to the main portion (base circle portion), and the entire upper surface of the upper half is formed as a valve-opening inclined first cam surface 50 that is in rolling contact with the first follower surface 45a. And the entire lower surface of the lower half is in contact with the second follower surface 45b.
Is configured as

The first and second cam surfaces 50, 51
Are formed in the same profile, and the first and second base circle portions 50a and 51a, which are base portions, respectively.
The ramp portions 50b, 51b are formed in a gentle arc surface, and the first and second lift portions 50c, 51 on the distal end side.
c is formed on an arc surface larger than the curvature of the first and second ramp portions 50b and 51b.
c, 51c, the third and fourth ramp portions 50d. 5
1d is formed. Therefore, the lift curve of the follower member 45 with respect to the rotation angle θ of the swing cam 46 is set to have an S-shaped curve characteristic as shown in FIG.
The third and fourth ramp sections 50d. Due to the presence of 51d, the sliding switching of each cam surface 50, 51 at the time of switching the vertical movement of the armature 30 can be smoothly performed.

Further, as shown in FIGS. 5 and 6, the swing cam 46 is positioned at a position where the base circle portions 50a and 51a of the cam surfaces 50 and 51 are in contact with the follower surfaces 45a and 45b. Electromagnets 31, 32 facing the upper and lower surfaces of the
The outer diameters of the base circle portions 50a and 51a are set so as to form minute gaps Go and Gc between the upper and lower surfaces.

As shown in FIG. 2, the urging means 47 has a cylindrical portion projecting from the inner surface of the lower wall of the casing body 29a in the axial direction, that is, toward the outer surface 52 of the swing cam 46. And a sliding hole 54 formed in the
4 includes a plunger 55 slidably provided in the inside 4 and a coil spring 56 which is a spring member for urging the plunger 55 in a direction substantially toward the central portion 52a of the outer surface 52.

The sliding hole 54 has a stepped diameter on the inner and outer sides and a substantially stepped portion 54a at a substantially central portion, and a disk-shaped lid 57 having an opening at the outer large diameter portion.
Is blocked by

The plunger 55 has an annular locking portion 55a integrally formed on the outer peripheral edge of the base portion for locking to the step portion 54a to restrict the maximum advance movement, and a tip portion 55b is formed in a hemispherical shape. I have. Also, this tip 55b is
When the swing cam 46 is in the non-swing state, the swing cam 46
A gap G having a predetermined size is formed between the outer surface 52 and the outer surface 52 such that the upper surface or the lower surface of the outer surface 52 is brought into contact when the swing cam 46 starts swinging and slightly tilts. It has become.

One end of the coil spring 56 is resiliently held on the inner surface of the lid 57, while the other end is resiliently held on the bottom surface of the concave portion on the base side of the plunger 55, so that the plunger 55 is always in the direction of the outer surface 52. Is energizing. The urging means 4
The plunger 55 of No. 7 may be provided with a roller as described in a second embodiment described later.

In the following, the operation of the present embodiment will be described. First, when the engine is stopped, the energization signal is not output from the electronic control unit 40 to each of the electromagnetic coils 31b and 32b of both electromagnets 31 and 32, and the non-energization state is set. ing. For this reason, as shown in FIG.
Due to the relative spring force of 33, it is held at a substantially neutral position in the gap S, and the intake valve 23 is also at a neutral position slightly away from the valve seat 22a. At this point, the swing cam 46 has its own weight, so that the second lift portion 51c of the second cam surface 51 has its follower surface 45 as shown in FIG.
b.

When the engine is started, the electronic control unit 40
When an energizing signal is output to the electromagnetic coil 32b of the valve-opening electromagnet 32 from the above, the armature 30 is attracted to the electromagnet 32 and descends by the spring force of the valve-opening side spring 33 as shown in FIG. For this reason, the follower member 45 is also lowered via the armature rod 38 to lower the lower end 38b.
Presses the stem end 23d downward. As a result, the intake valve 23 moves downward in the downward stroke, that is, in the direction in which the valve opens to the maximum, against the spring force of the valve-closing spring 28.

On the other hand, when the intake valve 23 is closed, the energization to the valve-opening electromagnet 32 is cut off and the electromagnetic coil 31b of the valve-closing electromagnet 31 is energized. The follower member 45 is raised against the spring force of the valve-opening spring 33 by the suction force of the valve-closing spring 31 and the spring force of the valve-closing spring 28. As a result, the intake valve 23 is raised by the spring force of the valve-closing side spring 28, and the umbrella portion 23d is seated on the valve seat 22a and closed.

When the follower member 45 rises or descends, the upper and lower portions of the outer side surface 52 of the swing cam 46 at the time of opening and closing the intake valve 23 are pressed by the tip portion 55 b of the plunger 55. While the cam surfaces 50 and 51 are in rolling contact with the respective follower surfaces 45a and 45b, the cam support shaft 49
To rotate clockwise or counterclockwise around
As shown in FIG. 7, an effective damping braking action can be obtained in the terminal region (open-closed circle region) of the opening / closing operation of the intake valve 23.

In other words, taking as an example the case where the intake valve 23 is closed, the urging force of the opening / closing valve-side springs 33, 28 in the opening / closing direction on the oscillating cam 46 is limited to the end area of the opening / closing stroke of the intake valve 23. Then, each becomes almost zero.

That is, for example, when the intake valve 23 is closed, the swinging cam 4 is moved as the valve stem 23b is raised by the electromagnetic attraction force and the spring force of the valve closing spring 28.
3 and 6, the contact point P is transferred from the second ramp portion 51b to the base circle portion 51b side. For this reason,
The moment at which the spring force of the valve closing spring 28 is transmitted to the swing cam 46 approaches zero, and therefore the swing cam 4
The spring force of the valve-closing-side spring 28 transmitted from the motor 6 to the armature rod 38 and the armature 30 approaches zero. In particular, in addition to the spring force of the valve-opening side spring 33, the urging means 47
The armature 30 and the intake valve 23 are effectively braked in the end region of the closing stroke because the spring reaction force acts on the armature 30 and the resultant force increases.

[0051] Such a unique action also occurs when the valve is opened. Therefore, basically, the first and second swing cams 46
The sudden movement of the armature 30 can be mechanically suppressed from the ramp portions 50b and 51b to the base circle portions 50a and 51a. As a result, the intake valve 23 has a gentle operation characteristic in the terminal region of the opening / closing stroke. can get. in short,
The swing cam 46 swings by the attraction force of the opening / closing side springs 33 and 28 and the electromagnets 31 and 32, and a rotational moment acts to increase the braking force, thereby obtaining a cushioning effect.

Moreover, as described above, both springs 28,
As shown in FIG. 7B, the spring resultant force acting on the armature of the armature 33 and the urging means 47 has a characteristic that increases sharply from near the upper limit and the lower limit of the armature 30, respectively. It effectively acts as a braking force in the terminal region at the time.

Therefore, as shown in FIG. 7A (particularly, a broken line), the intake valve 23 can obtain a stable damping action at the time of opening / closing operation. As a result, the umbrella portion 23a and the valve seat 22a
In addition, a violent collision between the armature 30 and the on-off valve electromagnets 32 and 33 is avoided, and the occurrence of hitting noise, wear, breakage, and the like is prevented.

Further, in this embodiment, as shown in FIGS. 5 and 6, when the armature 30 is moved up and down to the maximum, the upper and lower surfaces of the armature 30 and the opposing surfaces of the electromagnets 31 and 32 are moved by the swing cam 46. Since the active small gaps Go and Gc are formed between the armatures 30, the collision between the armature 30 and each of the electromagnets 31 and 32 can be more reliably avoided.

Further, as described above, especially the intake valve 23
For example, when the swing cam 46 attempts to swing up and down to the maximum in the end region of the opening operation, the tip 55b of the plunger 55 is moved by the spring force of the coil spring 57 as shown in FIG. The upper side of the outer side surface 52 of the pressing member 46 is pressed to urge the swing cam 46 to return to the neutral position. Therefore, a strong return torque is applied to the swing cam 46 in the direction of the neutral position in the vicinity of the maximum downward rotation position. Thereby, a more effective braking action on the armature 30 can be obtained.

On the other hand, in the terminal region when the intake valve 23 is closed, as shown in FIG.
5b presses the lower side of the outer surface 52 of the swing cam 46 to urge the swing cam 46 to return to the neutral position. For this reason,
A strong return torque is applied to the swing cam 46 toward the neutral position in the vicinity of the maximum upward rotation position. by this,
An even more effective braking effect on the armature 30 can be obtained.

Further, as shown in FIG. 1, when the intake valve 23 is slightly opened and the swing cam 46 is at a substantially neutral position, a gap G is formed between the outer surface 52 and the plunger tip 55b. Are formed and are in a non-contact state with each other, so that friction in this region is reduced, and the vertical operating speed of the armature 30 and the intake valve 23 is improved.

Further, since the swing cam 46 is supported by both the cam support shaft 49 and the plunger 55 in a double-supported state, the support rigidity of the swing cam 46 is increased, and the swing operation of the swing cam 46 is stable and reliable. Become. As a result, the fluctuation of the minute gaps Go and Gc formed between the upper and lower surfaces of the armature 30 and the opposing surfaces of the electromagnets 31 and 32 is suppressed, and the collision between the members as described above can be reliably avoided. .

Further, the urging means 47 in this embodiment
Is not provided directly on the swing cam 46 but is provided on the casing body 29a, so that an increase in the inertial force of the armature 30 can be suppressed and durability can be improved.

FIG. 8 shows a second embodiment according to the fourth aspect of the present invention, in which the structure of the braking mechanism 25 is modified.
A cam 60 is provided integrally on the outer surface of the lower end of the armature rod 38, and a braking means 61 similar to the urging means 47 of the first embodiment is provided on the lower wall of the casing body 29a. On the opposite side of the braking means 61 across the armature rod 38, a supporting means 70 for supporting the rear surface of the armature rod 38 opposite to the cam 60 is provided.

That is, the cam 60 is formed in a substantially U-shape on a part of the outer surface of the armature rod 38, and protruding portions 60a, 60b are provided at upper and lower ends along a radial direction. A substantially U-shaped cam surface 62 is formed along the vertical direction of the outer surface. The cam surface 62 has a central portion 62a in the up-down direction formed in a flat shape, and the protrusions 6 extending from upper and lower edges of the central portion 62a.
0a, 60b are formed at curved surface portions 62b, 62c having a predetermined radius of curvature along the leading edge.

On the other hand, the braking means 61 includes a sliding hole 64 formed in a cylindrical portion 63 protruding in the axial direction on the inner surface of the lower wall of the casing body 29a, and a sliding hole 64 formed in the cylindrical portion 63. It comprises a plunger 65 slidably provided, and a coil spring 66 which is a spring member for urging the plunger 65 in the direction of the substantially central portion 62a of the cam surface 62.

The sliding hole 64 has an inner and an outer part formed in a step diameter shape and a step part formed substantially in the center.
The opening of the outer large-diameter portion is closed by a disk-shaped lid 67.

The plunger 65 has an annular locking portion integrally formed on the outer peripheral edge of the base portion to lock the stepped portion so as to restrict the maximum advance movement. The plunger 65 is rotatably supported by the support shaft 68 at the distal end portion 65a. Roller 69 is provided. When the armature 30 is located at an intermediate position in the vertical direction as shown in FIG. 9, a gap G having a predetermined size is provided between the outer peripheral surface of the roller 69 and the central portion 62a of the cam surface 62.
Is formed, and the outer peripheral surface of the roller 69 near the maximum stroke of the armature rod 38 vertically,
The cam surface 62 comes into contact with a curved surface portion 62b or 62c. The radius of curvature of the outer peripheral surface of the roller 69 is set smaller than the radius of curvature of each of the curved surface portions 62b and 62c.

The coil spring 66 has one end resilient on the inner surface of the lid 67 and the other end resilient on the bottom surface of the base-side concave portion of the plunger 65 so that the plunger 65 is always in the direction of the cam surface 62. It is energizing.

The supporting means 70 is provided opposite to the braking means 61, and projects horizontally from the inner peripheral surface of the casing body 29a in the axial direction of the armature rod 38; A support roller 73 is provided rotatably on a roller shaft 72 fixed to the distal end of the armature 71 and rolls on the rear surface of the armature rod 38.

Therefore, according to this embodiment, as described above, for example, the armature rod 38 further strokes downward from the intermediate stroke position where the intake valve 23 shown in FIG. When trying to open to the maximum, first, the outer peripheral surface of the roller 69 of the plunger 65 starts to contact the upper curved surface portion 62b of the cam surface 62,
When the stroke is further downward, as shown in FIG. 10, the roller 69 is pushed back to the upper curved portion 62b, and gradually presses the curved portion 62b by the spring force of the coil spring 67 to apply a braking force to the armature rod 38.

Thus, the armature 30 and the intake valve 23 are effectively braked at the end of the open stroke. As a result, a violent collision between the armature 30 and the valve-opening electromagnet 32 is avoided, and the occurrence of hitting noise, wear, breakage, and the like is prevented.

On the other hand, when the armature rod 38 strokes upward to close the intake valve 23,
First, when the outer peripheral surface of the roller 69 starts to contact the lower curved surface portion 62c of the cam surface 62 and further strokes upward,
As shown in FIG. 11, while the roller 69 is pushed back to the lower curved portion 62c, the spring force of the coil spring 67 gradually presses the curved portion 62c to apply a braking force to the armature rod 38.

As a result, the armature 30 and the intake valve 23 are effectively braked at the end of the closed stroke. As a result, a violent collision between the umbrella portion 23a, the valve seat 22a, and the armature 30 and the valve closing electromagnet 33 is avoided,
The occurrence of hitting noise, wear or breakage is prevented.

Further, in this embodiment, since the members such as the follower portion 45 and the oscillating cam 46 as in the first embodiment are eliminated, the inertial mass of the armature rod 38 is smaller than that in the first embodiment. As a result, the operation response of the armature 30 is improved.

Further, at a slight downward stroke position of the armature rod 38, a gap G is formed between the outer peripheral surface of the roller 69 and the central portion 62a of the cam surface 62, and the two are brought into a non-contact state. Therefore, the occurrence of friction of the armature rod 38 during this time is avoided. As a result, the operating speed of the intake valve 23 increases.

The roller 69 is connected to each curved surface portion 62.
b and 62c, when the armature rod 38 is pressed in the opposite direction, the supporting means 70 is pressed against the pressing force.
Roller 73 supports the rear surface of the armature rod 38, so that the moment of the armature rod 38 can be canceled. Also, armature rod 38
The back surface is supported by the support roller 73 in rolling contact with it, so that the occurrence of friction here can be sufficiently suppressed.

The present invention can be applied not only to the intake valve side but also to only the exhaust valve side. When the present invention is applied to the exhaust valve side, the rapid movement of the exhaust valve at the time of opening can be regulated, so that combustion can be prevented. Sudden emission of gas is suppressed, and as a result, exhaust noise can be reduced. Also, the cam 62 is
It can be formed separately from the armature rod 38.

[0075]

As is apparent from the above description, claim 1
According to the invention described in the above, since the swinging cam can sufficiently brake the sudden opening / closing operation in the opening / closing terminal region of the engine valve, severe collision between the umbrella portion and the valve seat, or between the armature and the opening / closing valve electromagnet is mitigated. You. As a result, it is possible to prevent the generation of a violent impact sound and the occurrence of wear or breakage.

Further, when the swing cam swings to the maximum in the vertical direction in the end region of the opening / closing operation of the engine valve, the urging means presses the upper or lower outer surface of the swing cam to swing. Since the cam is urged to return to the neutral position, a strong return torque can be applied near the maximum swing of the swing cam. Thereby, a more effective braking action can be obtained.

According to the second aspect of the present invention, since the urging means is provided separately from the movable member such as the swing cam, an increase in the inertial mass of the armature is suppressed, and the operation of the armature is suppressed. A decrease in responsiveness can be prevented.

According to the third aspect of the present invention, since the friction between the swing cam and the urging means therebetween can be avoided by the gap, the operating speed of the armature or the engine valve can be prevented from lowering. .

According to the fourth aspect of the present invention, the rapid opening and closing operation of the engine valve in the open / close end region can be sufficiently braked by the braking mechanism. Intense collisions are mitigated.
As a result, it is possible to prevent the generation of a violent impact sound and the occurrence of wear or breakage.

Further, since the cam is simply formed on the armature rod of the braking mechanism, the inertial mass of the armature is further reduced, so that the operation response of the armature and the engine valve is improved.

According to the fifth aspect of the present invention, since the structure of the braking means is simplified, the manufacturing workability is improved and the cost can be reduced.

According to the sixth aspect of the present invention, since the friction with the cam surface can be sufficiently reduced by providing the rollers, it is possible to further improve the operation response of the armature.

According to the seventh aspect of the present invention, since the gap between the armature rod and the braking means during the gap can be prevented from occurring, a decrease in the operating speed of the armature can be prevented.

According to the eighth aspect of the present invention, since the back surface of the armature rod is supported by the support means, the moment of the armature rod caused by the pressing force of the braking means can be canceled.

According to the ninth aspect of the present invention, since the structure of the supporting means is simple, the manufacturing operation is easy and the increase in the weight of the entire apparatus can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view of a swing cam provided in the embodiment.

FIG. 4 is a characteristic diagram showing a rotation angle of a swing cam with respect to a vertical stroke of an armature.

FIG. 5 is a longitudinal sectional view showing an operation at the time of valve opening.

FIG. 6 is a longitudinal sectional view showing an operation at the time of valve closing.

FIG. 7A is an opening / closing timing characteristic diagram of an intake valve, and FIG. 7B is a drawing of an attraction force of each electromagnet and a spring force characteristic of each spring.

FIG. 8 is a longitudinal sectional view showing a second embodiment.

FIG. 9 is a sectional view taken along line BB of FIG. 8;

FIG. 10 is a longitudinal sectional view showing the operation at the time of valve opening.

FIG. 11 is a longitudinal sectional view showing the operation at the time of closing the valve.

FIG. 12 is a longitudinal sectional view showing a conventional device.

13A is a characteristic diagram of the opening / closing timing of the intake valve, and FIG. 13B is a characteristic diagram of the attraction force of each electromagnet and the spring force of each spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Cylinder head 23 ... Intake valve 25 ... Braking mechanism 28 ... Valve closing spring 29 ... Casing 30 ... Armature 31 ... Valve closing electromagnet 32 ... Valve opening electromagnet 33 ... Valve opening side spring 38 ... Armature rod 45 ... Follower member 46: swing cam 47: urging means 50: first cam surface 51: second cam surface 60: cam 61: braking means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G018 AB07 AB09 AB16 BA38 CA12 DA35 DA41 EA01 EA02 EA09 EA11 EA16 EA19 EA31 EA32 FA01 FA06 FA07 GA22 GA31 GA33 3G092 AA11 DA01 DA02 DA07 DG09 EA03 EA04 EA22 FA13 HE13 HA01 HAX 3H106 DA05 DA25 DB02 DB13 DB26 DB32 DB38 DC02 DD07 DD14 EE19 EE20

Claims (9)

[Claims] 1. An armature associated with an engine valve, an electromagnet for opening and closing the engine valve by sucking the armature to open and close the engine valve, and closing and opening the engine valve in a closing direction and an opening direction. An electromagnetic drive device for an engine valve, comprising: a spring member that is biased and held at a neutral position; and a braking mechanism that brakes the opening and closing speed of the engine valve, wherein the braking mechanism is linked to the armature, and A swinging cam having a pair of follower members having a pair of follower surfaces, and a pair of cam surfaces for rolling contact with the respective follower surfaces as the armature moves up and down to brake the opening / closing speed in the terminal region of the opening / closing operation of the engine valve; Biasing means for resiliently contacting a predetermined position on an outer surface formed between the two cam surfaces of the swing cam to bias the swing cam to a substantially neutral position in the rotation direction. The electromagnetic drive of the engine valve. 2. A plunger provided in a casing accommodating the armature and the electromagnet so as to be able to advance and retreat in an outer surface direction of the swing cam, and a spring for urging the plunger in the outer surface direction. 2. The electromagnetic drive device for an engine valve according to claim 1, wherein the electromagnetic drive device comprises a member. 3. At a neutral position in a rotating direction of the swing cam,
3. The electromagnetic drive device for an engine valve according to claim 2, wherein a gap is formed between the outer surface and the tip edge of the plunger. 4. An armature linked to an engine valve via an armature rod, an electromagnet for opening and closing the engine valve for sucking the armature to open and close the engine valve, and closing the engine valve. An electromagnetic drive device for an engine valve, comprising: a spring member that urges in a direction and an opening direction to hold the neutral position, and a braking mechanism that brakes an opening and closing speed of the engine valve, wherein the braking mechanism includes the armature. A cam provided on the outer surface of the rod and having a substantially U-shaped cam surface along the axial direction of the armature rod; and an engine valve wherein the distal end elastically contacts the cam surface with the stroke of the armature rod. And a braking means for braking an opening / closing speed in a terminal region of the opening / closing operation of the engine. 5. The braking means comprises a plunger provided in a casing containing the armature and the electromagnet so as to be able to advance and retreat in the cam surface direction, and a spring member for urging the plunger in the outer surface direction. The electromagnetic drive device for an engine valve according to claim 4, wherein: 6. The roller according to claim 5, wherein a roller that rolls on the cam surface is provided at a tip end of the plunger.
An electromagnetic drive for an engine valve as described. 7. The engine according to claim 5, wherein a gap is formed between the cam surface and a tip portion of the plunger or the roller at a neutral position in a vertical direction of the armature. Electromagnetic drive of the valve. 8. A support means for supporting a radial pressing force on the armature rod from the brake means at a position substantially opposite to the brake means with the armature rod interposed therebetween. An electromagnetic drive device for an engine valve according to any one of claims 4 to 7. 9. An electromagnetic drive device for an engine valve according to claim 8, wherein said support means supports an armature rod via a roller in opposition to said braking means.