JP2002071042A - Electromagnetic drive valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic drive valve which ensures valve operation by preventing rotation of the armature with a simple construction. SOLUTION: In the electromagnetic drive section 20, an armature 14 having long narrow and approximately rectangular profile whose both ends form protrusions for magnetic force 14a, is fixed to a valve body 11. A pair of magnetic protrusions 28A and 28 which are extended toward the side of the protrusions for magnetic force 14a of the armature 14, are located at both ends in the longitudinal direction of outer cores 27A and 27 of cores 24A and 24 of the first magnet 22 and the second magnet 23 which are placed on both sides of the armature 14. The magnetic protrusions 28A and 28 serve to concentrate magnetic flux passing through the core 24 when an electromagnetic coil 29 is energized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve which is electromagnetically driven, for example, as an intake / exhaust valve of an internal combustion engine.

[0002]

2. Description of the Related Art Generally, an electromagnetically driven valve of this type is provided with a valve body for opening and closing an intake port or an exhaust port, an armature displaced together with the valve body, an electromagnet comprising an electromagnetic coil and a core, and an electromagnet for attracting the armature, and an armature separated from the electromagnet. A coil spring or the like that urges the coil spring is provided. Then, the armature is displaced at a predetermined timing through the energization control of the electromagnet, so that the valve body is driven to open and close.

A plurality of such electromagnetically driven valves are provided on the cylinder head in accordance with the number of cylinders of the internal combustion engine. Distance is restricted. Therefore, Japanese Patent Laid-Open No. 9-25
As shown in JP-A-6826 and JP-A-11-81941, the armature and the pair of cores are formed in an elongated and substantially rectangular shape so as to satisfy the distance between valve shafts while securing the area of the armature. Drive valves have been proposed.

[0004]

However, in the process of displacing the armature, the rectangular armature rotates together with the valve element because the coil spring receives a rotational force as the coil spring expands and contracts. When the electromagnetically driven valve accommodates a rectangular armature in the housing, the rectangular armature contacts the inner surface of the housing and increases friction, thereby adversely affecting operability. Further, in a configuration in which there is no partition such as a housing between the rectangular armatures of the electromagnetically driven valves adjacent to each other, when the rectangular armature rotates, there is a possibility of interfering with the rectangular armatures of the adjacent electromagnetically driven valves, The operability may be adversely affected.

[0005] In order to prevent the rotational force caused by the expansion and contraction of the coil spring from acting on the rectangular armature, it is conceivable to provide a thrust bearing at the contact portion of the coil spring. In this case, the number of parts increases, the structure becomes complicated, and the cost increases.
The increase in the number of parts also causes an increase in the size of the electromagnetically driven valve.
Further, when the thrust bearing is provided at the contact portion of the coil spring as described above, it is possible to prevent the rotational force due to the expansion and contraction of the coil spring from exerting on the armature, but the vibration of the internal combustion engine and the vibration due to running of the vehicle, etc. The inertia force based on the rotation may reach the armature as a rotational force. The rotational force due to such factors cannot be removed by the thrust bearing, and the rectangular armature rotates, which may adversely affect the operability of the rectangular armature.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to ensure the operability by reliably suppressing the rotation of the armature with a simple configuration and to increase the cost. It is to provide an electromagnetically driven valve that can be suppressed.

[0007]

The means for achieving the above object and the effects thereof will be described below. The invention according to claim 1 has an armature displaced together with the valve body, and a pair of electromagnets disposed on both sides of the armature in the displacement direction of the armature, wherein the armature and the pair of electromagnets have a non-axisymmetric shape. Wherein each of the electromagnets is provided with a magnetic projection extending toward a peripheral edge of the armature.

According to the first aspect of the present invention, when the electromagnetic coil is energized in the process of displacing the armature, the magnetic flux concentrates on the magnetic projection and an electromagnetic attraction acts between the magnetic projection and the peripheral edge of the armature. Become like For this reason, even if a rotational force acts on the armature in the process of displacing the armature, the rotational force of the armature is canceled by the electromagnetic attraction force acting between the magnetic projection and the armature, and the rotation of the armature is reliably prevented. In this manner, the rotation of the armature is prevented, so that the operability of the electromagnetically driven valve can be ensured. In addition, a simple configuration change that only requires the provision of the magnetic projections is sufficient, and an increase in cost can be suppressed.

According to a second aspect of the present invention, in the electromagnetically driven valve according to the first aspect, the electromagnet includes an electromagnetic coil and a core, and the magnetic projection is connected to the core or to the core. It is characterized by being provided so as to be close to each other.

According to the second aspect of the present invention, since the magnetic projection is provided so as to be continuous with or close to the core, the magnetic flux transmitted through the core is easily concentrated on the magnetic projection, The electromagnetic attraction between the armature and the peripheral edge of the armature can be increased. Therefore, even if a rotational force acts on the armature in the process of displacing the armature, the rotational force of the armature is canceled out by a part of the electromagnetic attractive force acting between the magnetic projection and the armature, and the rotation of the armature is reliably prevented. Is done.

The invention described in claim 3 is the first and second inventions.
In the electromagnetically driven valve according to any one of the above, the armature and the pair of electromagnets are formed in a substantially rectangular shape, and the magnetic protrusion is provided so as to face at least one of both peripheral edges in the long direction of the armature. It is characterized by being.

According to the third aspect of the present invention, since the magnetic projection is provided so as to extend toward the peripheral edge of the armature in the longitudinal direction, the distance from the axis of the valve body to the peripheral edge of the armature (arm length). Becomes large, a large moment is generated by the electromagnetic attraction force of the magnetic projection, and the rotation of the armature is reliably prevented, and while securing the area of the armature,
The magnetic projections can be efficiently provided by reducing the size of the magnetic projections.

According to a fourth aspect of the present invention, in the electromagnetically driven valve according to any one of the first to third aspects, the magnetic projection is positioned on a side of a peripheral edge of the armature in a process of displacing the armature. It is characterized by being provided.

According to the fourth aspect of the present invention, since the magnetic projection is located on the side of the peripheral edge of the armature in the process of displacing the armature, the magnetic projection increases the size of the electromagnetically driven valve in the direction of displacement of the armature. Can be suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the electromagnetically driven valve of the present invention is applied to an intake valve and an exhaust valve of an internal combustion engine will be described below with reference to FIGS. Since the intake valve and the exhaust valve have the same configuration, only the exhaust valve will be described below.

As shown in FIG. 1, the exhaust valve 10 includes a valve body 11, an upper coil spring (hereinafter referred to as an upper spring) 17 for opening and closing the valve body 11, and a lower coil spring (hereinafter referred to as a lower spring). 1
8 and an electromagnetic drive unit 20.

The valve body 11 includes a valve shaft 12 supported reciprocally with respect to the cylinder head 35, and an umbrella portion 13 fixed to a lower end of the valve shaft 12. An exhaust port 37 communicating with the combustion chamber 36 is formed in the cylinder head 35, and the umbrella portion 13 is separated from and seated on a valve seat 38 formed in the cylinder head 35 as the valve shaft 12 reciprocates. 37 is opened and closed.

The upper retainer 1 is provided at the upper end of the valve shaft 12.
5 is fixed. An upper spring 17 is disposed between the upper retainer 15 and the cap 39 fitted to the cylinder head 35, and the valve body 11 is opened by the upper spring 17 (the direction D1 in FIG. 1).
Is always energized. On the other hand, a lower retainer 16 is fixed to a substantially central portion of the valve shaft 12. A lower spring 18 is disposed between the lower retainer 16 and the cylinder head 35. The lower spring 18 constantly urges the valve element 11 toward the valve closing side (the direction D2 in FIG. 1).

The electromagnetic drive unit 20 includes a housing 21 fixed to a cylinder head 35, an armature 14, a first electromagnet 22, a second electromagnet 23, and the like. An armature 14 made of a magnetic material is fixed to the valve body 11 in the housing 21. As shown in FIG. 4, the armature 14 is formed in a slender, substantially rectangular shape which is point-symmetrical about the valve shaft 12, more precisely, in a slender octagonal shape. -Shaped magnetic force acting projection 1
4a.

A first electromagnet 22 and a second electromagnet 23 are disposed in both openings of the housing 21 so as to be located on both sides of the armature 14 in the direction of displacement of the armature 14.

Next, the first and second electromagnets 22 and 23 will be described. Note that the first and second electromagnets 22 and 23 have the same configuration, and the two electromagnets 22 and 23 are arranged so that their constituent elements face each other.
, The components of the first electromagnet 22 are denoted by “A” and the description of the components of the second electromagnet 23 is omitted.

As shown in FIG. 2, the second electromagnet 23 has a core 24 made of a magnetic material, and an annular electromagnetic coil 29 disposed about the valve shaft 12 as a center. As shown in FIGS. 1 and 2, the core 24 includes a core plate 25, an inner core 26 fixed to a central portion of the core plate 25, and an annular outer core 27 fixed to the core plate 25 so as to surround the inner core 26. Consists of The core 24 is formed in an elongated rectangular shape that is point-symmetric about the valve shaft 12. Further, the dimension of the outer core 27 in the short direction is set substantially equal to the dimension of the armature 14 in the short direction, but the dimension of the outer core 27 in the long direction is set to be larger than the dimension of the armature 14 in the long direction. .

Through holes 30 and 31 are formed in the center portions of the core plate 25 and the inner core 26, respectively.
The valve shaft 12 of the valve body 11 is slidably supported through the inside of the valve body 1. An electromagnetic coil 29 is disposed between the inner core 26 and the outer core 27, and the second electromagnet 23 is formed in an elongated rectangular shape that is point-symmetric about the valve shaft 12. The electromagnetic coil 29 is electrically connected to the drive circuit 40. The armature 1 is generated by the electromagnetic force generated in the electromagnetic coil 29 through the energization control of the drive circuit 40.
4 is attracted to the electromagnet, and its position is displaced.

A pair of magnetic projections 28 extending toward the side of the magnetic force acting projections 14a of the armature 14 are integrally provided at both ends of the outer core 27 in the longitudinal direction. Both magnetic projections 28 concentrate the magnetic flux transmitted through the core 24 when the electromagnetic coil 29 is energized.

The inner core 26 and the outer core 27
A pair of permanent magnets 32 are opposed to each other so as to sandwich the valve shaft 12 in the short direction of the core 24 of the electromagnetic coil 29.

Accordingly, the valve body 11 is driven to close by the armature 14 being attracted by the electromagnetic force generated by the first electromagnet 22 and the magnetic force of the permanent magnet 32A, and the electromagnetic force generated by the second electromagnet 23 and the permanent magnet The armature 14 is attracted by the magnetic force of the armature 32 to drive the valve open.

When the first electromagnet 22 and the second electromagnet 23 are not energized, the armature 14 is attracted to the lower surface of the first electromagnet 22 by the magnetic force of the permanent magnet 32A. Permanent magnet 32
Is attracted to the upper surface of the second electromagnet 23 by the magnetic force, and the neutral position where the biasing forces of the upper spring 17 and the lower spring 18 are balanced, that is, the first position here.
One of the states held at a substantially intermediate position between the electromagnet 22 and the second electromagnet 23 is taken.

Next, the opening and closing operation of the exhaust valve configured as described above will be described. First, when energization of the electromagnetic coil 29A of the first electromagnet 22 is started by the drive circuit 40, the armature 14 is attracted by the core 24A excited by the magnetic force of the permanent magnet 32A and the electromagnetic force of the electromagnetic coil 29A. Due to this suction force, the armature 14 is moved in the direction indicated by the arrow D in FIG.
2 and is brought into contact with the core 24A. In the displacement process of the armature 14, a rotational force is applied to the armature 14 in accordance with the expansion and contraction of the upper spring 17 and the lower spring 18, but the magnetic flux concentrates on the two magnetic projections 28A and the magnetic force between the two magnetic projections 28A and the armature 14 Electromagnetic attraction acts between the operation protrusion 14a. Therefore, the rotational force of the armature 14 by the springs 17 and 18 is canceled by a part of the electromagnetic attraction force acting between the magnetic projection 28A and the armature 14, and the rotation of the armature 14 is reliably prevented. Thus, the armature 14 has the core 24
A is displaced so as to match A and comes into contact with the core 24A. Thus, in a state where the armature 14 and the core 24A are in contact with each other by energizing the electromagnetic coil 29A,
The urging force of the lower spring 18 causes the valve shaft 12 to move in the direction of the arrow D.
Since the valve body 11 is displaced in two directions, the valve body 11 is seated on the valve seat 38 to be in a closed state.

Next, when the valve body 11 in the closed state is opened, the drive circuit 40 first energizes the electromagnetic coil 29A in the opposite direction. As a result, the electromagnetic force of the electromagnetic coil 29A is generated so as to cancel the magnetic force of the permanent magnet 32A, the attractive force of the core 24A disappears, and the urging force of the upper spring 17 causes the valve shaft 12 and the armature 1 to move.
4 begins to displace in the direction of arrow D1.
The valve body 11 is separated from the valve seat 38 to be in an open state.

When the valve shaft 12 and the armature 14 are further displaced and the amount of displacement reaches a predetermined value, the drive circuit 4
By 0, energization of the electromagnetic coil 29 of the second electromagnet 23 is started. As a result, the armature 14 is attracted by the core 24 excited by the magnetic force of the permanent magnet 32 and the electromagnetic force of the electromagnetic coil 29. When the armature 14 is displaced in the direction of the arrow D1 in FIG. 1 and comes into contact with the core 24 against the urging force of the lower spring 18 due to the suction force, the valve shaft 1
No. 2 is no longer displaced, and the lift amount of the valve body 11 is maximized. In the process of displacing the armature 14,
Rotational force due to the expansion and contraction of the upper spring 17 and the lower spring 18 is applied to the armature 14, but the magnetic flux concentrates on the two magnetic projections 28 and the two magnetic projections 28 and the armature 1
An electromagnetic attractive force acts between the magnetic force acting projection 14a and the magnetic force acting projection 14a. Therefore, both springs 17, 17 are caused by a part of the electromagnetic attractive force acting between the magnetic projection 28 and the armature 14.
The rotation force of the armature 14 by the armature 18 is canceled, and the rotation of the armature 14 is reliably prevented. Thus, the armature 14 is displaced so as to match the core 24 and comes into contact with the core 24.

Next, when the valve body 11 in the valve open state is to be closed again, first, the electromagnetic coil 2 is driven by the drive circuit 40.
9 is energized in a direction opposite to the above. As a result, the electromagnetic force of the electromagnetic coil 29 is generated so as to cancel out the magnetic force of the permanent magnet 32, the attraction force of the core 24 disappears, and the urging force of the lower spring 18 causes the valve shaft 12 and the armature 14 to move as indicated by the arrow D2. It starts to displace in the direction.

Thereafter, when the displacement of the armature 14 reaches a predetermined value, the drive circuit 40 starts energizing the electromagnetic coil 29A. As a result, the core 24 excited by the magnetic force of the permanent magnet 32A and the electromagnetic force of the electromagnetic coil 29A
A sucks the armature 14. The armature 14 is displaced in the direction of the arrow D2 in FIG. 1 against the urging force of the upper spring 17 and comes into contact with the core 24A by the suction force. In this state where the armature 14 and the core 24A are in contact with each other by energizing the electromagnetic coil 29A, the valve shaft 12 is displaced in the direction of arrow D2 by the urging force of the lower spring 18, so that the valve body 11 is And the valve is closed.

As described in detail above, according to this embodiment, the following excellent effects can be obtained. The electromagnetically driven valve according to the present embodiment is configured such that the magnetic projections 28A and 28 of the first electromagnet 22 and the second electromagnet 23 and the magnetic force acting projections 14 of the armature 14 during the displacement process of the armature 14.
a, the rotational force acting on the armature 14 in a non-contact state can be cancelled, and the rotation of the armature 14 can be reliably prevented. Since there is no interference, the operability of the electromagnetically driven valve can be ensured.

The magnetic projections 28 A, 28 are provided with respect to the cores 24 A, 24 of the first electromagnet 22 and the second electromagnet 23.
It is sufficient to simply change the configuration, and an increase in the cost of the electromagnetically driven valve can be suppressed.

The magnetic projections 28 A, 28 are provided on the cores 24 A, 24 of the first electromagnet 22 and the second electromagnet 23.
Are provided integrally, the magnetic flux transmitted through the cores 24A, 24 tends to concentrate on the magnetic projections 28A, 28, and the magnetic projections 14a of the magnetic projections 28A, 28 and the armature 14 are easily formed.
Can be increased, and rotation of the armature 14 can be reliably prevented.

Further, since the magnetic projections 28A, 28 are provided at the longitudinal ends of the cores 24A, 24,
The distance (length of the arm) from the valve shaft 12 to the magnetic force acting projection 14a of the armature 14 increases, and the magnetic projections 28A, 28
8, a large moment is generated by the electromagnetic attraction force, and rotation of the armature 14 can be reliably prevented. Therefore, while securing the area of the armature 14, the magnetic protrusions 28A,
The magnetic projections 28A and 28 can be efficiently provided by reducing the size of the magnetic projections 28.

Also, since the magnetic projections 28A, 28 are provided so as to be located on the side of the long edge of the armature 14 in the longitudinal direction, the electromagnetic projection valve 28A, 28 causes the electromagnetically driven valve to move in the displacement direction of the armature 14. Increase in size can be suppressed.

(Other Embodiments) Next, other embodiments of the electromagnetically driven valve will be described. 5 to 7 show different embodiments, in which the configuration of the electromagnet and the armature 14 in the electromagnetic drive unit of the electromagnetic drive valve is changed. In order to avoid redundant description, the same elements as those described in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

The armature 14 of the embodiment shown in FIG. 5 is formed in a slender, substantially octagonal shape that is symmetrical about the valve shaft 12 with respect to the point. Two magnetic force acting projections 14b are formed. Two magnetically acting projections 14 b of the armature 14 are provided at both ends of the outer core 27 of the electromagnet 41 in the longitudinal direction.
Two magnetic projections 42 extending toward the side are provided respectively. By providing the two small magnetic projections 42 at a distance in this manner, the magnetic flux passing through the core 24 can be more concentrated, and the armature 14
Swing can be reliably suppressed.

The armature 14 of the embodiment shown in FIG. 6 is formed in a slender, substantially rectangular shape which is point-symmetrical with respect to the valve shaft 12. An arc-shaped magnetic force acting projection 14c is formed. At both ends of the outer core 27 of the electromagnet 43 in the longitudinal direction, there are provided magnetic projections 44 having an arc surface along the arc-shaped magnetic force acting projection 14c of the armature 14. Therefore, even if the armature 14 rotates, the magnetic force acting projection 14c does not interfere (contact) with the magnetic projection 44.

The armature 14 of the embodiment shown in FIG. 7 is formed in a slender, substantially octagonal shape which is symmetrical about the valve shaft 12 with respect to the point. A narrow magnetic force acting projection 14d is formed. At both ends of the outer core 27 of the electromagnet 45 in the longitudinal direction, narrow magnetic projections 46 extending toward the magnetic force acting projections 14d of the armature 14 are provided. By forming the magnetic projections 46 narrow in this way, the electromagnetic attraction between the magnetic projections 46 and the magnetic force acting projections 14d of the armature 14 can be increased, and the rotation of the armature 14 is reliably suppressed. be able to.

The configuration of the above embodiment can be changed as appropriate, for example, as follows. In the above embodiments, the pair of magnetic projections 28 are provided on both ends of the outer core 27 in the longitudinal direction. However, the magnetic projections are provided on only one of both ends of the outer core 27 in the longitudinal direction. You may.

In each of the above embodiments, the outer core 27
Although magnetic projections 28 are provided at both ends in the longitudinal direction,
Magnetic protrusions may be provided at both ends in the short direction of the outer core 27.

In the above embodiments, the outer core 27
Although the magnetic projections 28 are provided integrally so as to extend from both ends in the longitudinal direction, separate magnetic projections may be provided and fixed so as to be continuous with or close to the outer core 27.

In the electromagnetically driven valve of each of the above embodiments, the housing 21 of the electromagnetically driven portion 20 may be omitted. In the above embodiments, the first electromagnet 22 and the second electromagnet 23 are provided with the permanent magnets 32A and 32.
The permanent magnets 32A and 32 may be omitted.

Next, other technical ideas that can be grasped from the above embodiment will be described below. (A) The electromagnetically driven valve according to any one of claims 1 to 4, wherein the pair of electromagnets includes a permanent magnet.

(B) A pair of coil springs for applying an urging force acting in a direction opposite to the electromagnetic force of the pair of electromagnets in the electromagnetically driven valve according to any one of (1) to (4) and (a). An electromagnetically driven valve comprising:

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an electromagnetically driven valve according to an embodiment.

FIG. 2 is a plan sectional view showing an electromagnet.

FIG. 3 is a sectional view taken along line 1-1 in FIG. 2;

FIG. 4 is a plan sectional view showing an armature and an electromagnet.

FIG. 5 is a plan sectional view showing an armature and an electromagnet according to another embodiment.

FIG. 6 is a plan sectional view showing an armature and an electromagnet according to another embodiment.

FIG. 7 is a plan sectional view showing an armature and an electromagnet according to another embodiment.

[Explanation of symbols]

11: valve element, 14: armature, 14a, 14b, 14
c, 14d: magnetic force acting projection, 17: upper (coil) spring, 18: lower (coil) spring, 22: first electromagnet, 23: second electromagnet, 24, 24A: core, 2
5, 25A: core plate, 26, 26A: inner core, 27, 27A: outer core, 28, 28A, 42,
44, 46: magnetic projection; 29, 29A: electromagnetic coil.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Sakuragi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Tatsuo Iida 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Masahiko Asano 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G018 AB09 AB16 BA38 CA16 DA40 DA41 DA43 FA01 FA06 FA07 FA11 GA02 GA14 GA18 GA22 3H106 DA07 DA25 DB02 DB12 DB26 DB32 DC02 DD02 DD03 EE34 EE48 FA08 GA13 KK17 5E048 AA08 AB01 AC05 AC06 AD07

Claims (4)

[Claims] 1. An armature displaced with a valve element, and a pair of electromagnets disposed on both sides of the armature in a direction of displacement of the armature, wherein the armature and the pair of electromagnets are formed in a non-axisymmetric shape. An electromagnetically driven valve, wherein each of the electromagnets is provided with a magnetic projection extending toward a peripheral edge of the armature. 2. The electromagnetically driven valve according to claim 1, wherein the electromagnet includes an electromagnetic coil and a core, and the magnetic projection is provided so as to be continuous with or close to the core. Is an electromagnetically driven valve. 3. The electromagnetically driven valve according to claim 1, wherein the armature and the pair of electromagnets are formed in a substantially rectangular shape, and the magnetic projections are formed at both circumferential edges of the armature in a longitudinal direction. An electromagnetically driven valve provided to face at least one of the following. 4. The electromagnetically driven valve according to claim 1, wherein the magnetic projection is provided on a side of a peripheral edge of the armature in a process of displacing the armature. .