JP2002295716A - Electromagnetic drive valve - Google Patents

Abstract

(57) [Problem] To provide an electromagnetically driven valve in which erosion of a heat conductive material is suppressed. SOLUTION: (1) An electromagnet in which a heat conductive material 2 in which a filler is dispersed in a resin is sealed between a coil 6 and cores 7 and 8 accommodating the coil is provided, and a valve is formed by an electromagnetic force of the electromagnet. An electromagnetically driven valve for driving an electromagnetically driven valve, wherein a portion of the heat conductive material exposed from the electromagnet is coated with an erosion resistant material having high erosion resistance to oil.
(2) An electromagnetically driven valve using, as the erosion-resistant material 1, a material having a low influence on wear.

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 (also referred to as an electromagnetic valve), and more particularly to an electromagnetically driven valve which suppresses erosion of a coil sealing material.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 2000-23432, in order to prevent a decrease in motor output by escaping resistance heat generated in a coil in a motor, a coil and a core accommodating the coil are connected. The space is sealed with a high heat conductive sealing material made of resin.
JP-A-2000-234 discloses a heat conductive material having high heat conductivity.
As shown in FIG. 32, a filler in which a ceramic such as alumina is dispersed in a thermosetting resin is used.

[0003]

An electromagnetically driven valve in which a heat conductive material of a filler-containing resin is sealed between a coil and a core accommodating the coil, as shown in FIG. Oil 30 mixes with the metal powder generated between the armature and the core, erodes the resin surface of the heat conductive material 31, and the alumina filler material 32 in the eroded resin 31 precipitates, and this alumina is polished. It becomes a material and promotes abrasion of the contact parts of the core and armature. If there is a step due to wear at the contact portion between the core and the armature, the lift amount of the valve changes, and when the electromagnetically driven valve is an intake / exhaust valve of an engine, there is a problem in that it deviates from engine specifications. An object of the present invention is to provide an electromagnetically driven valve in which erosion of a heat conductive material is suppressed.

[0004]

The present invention to achieve the above object is as follows. (1) An electromagnetically driven valve that includes an electromagnet in which a heat conductive material in which a filler is dispersed in a resin is sealed between a coil and a core that houses the coil, and drives the valve by an electromagnetic force of the electromagnet. An electromagnetically driven valve, wherein a portion of the heat conductive material exposed from the electromagnet is coated with an erosion resistant material having high erosion resistance to oil. (2) The electromagnetically driven valve according to (1), wherein a material having little influence on wear is used as the erosion-resistant material.

In the electromagnetically driven valve of (1), the portion of the heat conductive material exposed from the electromagnet is coated with an erosion-resistant material having high erosion resistance to oil, so that it is exposed to an oil mist atmosphere on which metal powder is deposited. Even if it is performed, the erosion of the heat conductive material is prevented, and the filler in the heat conductive material does not come out, so that the abrasion of the metal material (for example, the core or the armature) by the filler is suppressed. In the electromagnetically driven valve of the above (2), the erosion-resistant material includes a material having a low effect on wear,
For example, since the non-filler material is used, even if the erosion-resistant material is eroded in a minute amount, the filler material does not come out of the material, so that the wear of the metal material (core or armature) by the filler is suppressed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetically driven valve according to an embodiment of the present invention will be described with reference to FIGS. The electromagnetically driven valve 22 (FIG. 3) according to the embodiment of the present invention has a structure in which the heat conductive material 2 in which a filler is dispersed in a resin has a coil 6 and cores 7 and 8 (7 is an inner core, 8 is an outer core). ) Are sealed between the electromagnets 16 and 18 (16 is an upper electromagnet and 18 is a lower electromagnet).
The electromagnetically driven valve for driving the valve 19 (FIG. 3) by the electromagnetic force of (1) is formed by coating a portion of the heat conductive material 2 exposed from the electromagnets 16 and 18 with the erosion resistant material 1 having high erosion resistance to oil. . As the erosion-resistant material 1, it is desirable to use a material having a low effect on wear, for example, a non-filler material (a resin material containing no filler material).

More specifically, the coil 6 is positioned and supported between the inner core 7 and the outer core 8 by the coil positioning member 3, and the coil 6 and the inner core 7
And between the coil 6 and the outer core 8 are sealed with a thermally conductive material 2 having high thermal conductivity (for example, a resin containing alumina filler). The inner core 7 is provided with a hole through which the shaft of the armature 17 (FIG. 3) is slidably inserted. Further, a sliding bush 4 for slidably supporting the shaft of the armature 17 is fixed to the inner core 7 at the hole and the coaxial core. A permanent magnet 5 for assisting magnetic force is provided between the inner core 7 and the outer core 8.
Is provided. The inner core 7 and the outer core 8 are held by a holder 9. As shown in FIG. 4, each of the inner core 7 and the outer core 8 is provided with a slit 7a in the circumferential direction for suppressing eddy current generation.
8a are provided.

Although the field of use of the electromagnetically driven valve 22 is arbitrary, it can be used, for example, as a motor for reciprocatingly driving the intake / exhaust valve 19 of the engine as shown in FIG. The electromagnets 16 and 18 are arranged vertically symmetrically on the engine cylinder head, and an armature 17 is arranged so as to be slidable vertically with respect to the upper and lower electromagnets 16 and 18. When the armature 17 and the valve 19 are connected and no current flows through the coils 6 of the upper and lower electromagnets 16 and 18, the armature 17 is moved by the upper and lower springs 20 and 21.
Is held in a neutral position. Upper and lower electromagnet 1
When a current flows through any one of the coils 6 and 18, the armature 17 is attracted to the electromagnet to which the current has flowed by electromagnetic force. By switching the current to the coils 6 of the upper and lower electromagnets 16 and 18, the valve 19 opens and closes. The space between the upper electromagnet 16 and the lower electromagnet 18 is filled with oil mist.

As shown in FIGS. 5 and 6, the method of manufacturing the electromagnets 16 and 18 is such that a heat conductive material 2 in which a filler is dispersed in a resin is provided between a coil 6 and cores 7 and 8 accommodating the coil. A step of sealing by transfer molding (FIG. 5) and a step of casting a portion of the heat conductive material 2 exposed from the electromagnets 16 and 18 with an erosion resistant material 1 having high erosion resistance to oil by casting. (FIG. 6). As the erosion-resistant material 1, it is desirable to use a material having a low effect on wear, for example, a non-filler resin.

[0010] More specifically, in the transfer molding shown in FIG. . A heat conductive material 2 containing alumina filler (resin having an alumina content of 82.5 wt% and a heat conductivity of 2.1 W / mk) is put on the upper mold in the cylinder 12 as a filling component. The mold is clamped (step in FIG. 5) and pressed by a piston 13 as a filling component (step in FIG. 5), the heat conductive material 2 is sealed between the coil 6 and the cores 7 and 8, and cured for about 5 minutes. (Step of curing thermosetting resin, step of FIG. 5) Then, after-curing is performed at about 150 ° C. for about 2 hours (step of FIG. 5).

In the casting of FIG. 6, the electromagnet assembly enclosing the heat conductive material 2 is pressed and clamped by the upper die 14 of the casting molding apparatus (step of FIG. 6), and the erosion-resistant material is supplied from the filling machine 15. 1 (for example, 123 Bond
0G (silicone rubber) or the like)
The portions exposed from 6, 18 are coated (step in FIG. 6) to form a two-layer structure of a heat conductive material 2 and an erosion-resistant material 1.
The erosion-resistant material 1 is cured at 100 ° C. for 1 hour (step of FIG. 6).

Next, the operation of the electromagnetically driven valve according to the embodiment of the present invention will be described. As shown in FIG.
Heat conductive material 2 sealed between coil 6 and cores 7 and 8
If the oil tries to erode the exposed side ends of the electromagnets 16 and 18, the exposed side ends of the heat conductive material 2 from the electromagnets 16 and 18 are covered with the erosion-resistant material 1. The exposed side ends of the electromagnets 16 and 18 are not eroded by oil. Therefore, the alumina filler contained in the portion of the heat conductive material 2 that has fallen due to erosion, which has occurred in the conventional case of FIG.
No metal parts such as are worn. Further, even if the erosion-resistant material 1 is dropped in a minute amount, it is a non-filler material containing no alumina filler, and therefore does not wear metal parts.

A durability test was performed by driving the electromagnetically driven valve. In driving, the armature 17 reciprocates with respect to the cores 7, 8 and hits the cores 7, 8. At this time, if the heat conductive material 2 between the cores 7 and 8 and the coil 6 is not covered with the erosion-resistant material 1, the end faces of the cores 7 and 8 and the armature are formed by the alumina filler generated by the erosion of the heat conductive material 2. The end face 17 is worn, and a step is formed on the core end faces 7 and 8. FIG. 7 shows a step due to wear formed on the end face of the core (outer core 8) after the durability test in which the armature is reciprocated 200 million cycles with respect to the core.
This is shown in comparison with the conventional case. In the case of the upper electromagnet 16, the step is about 9 μm in the method of the present invention and about 21 μm in the related art, so that the depth of the step is 以下 or less of the conventional. In the case of the lower electromagnet 18, the step is about 5 μm in the method of the present invention and about 34 μm in the related art, so that the depth of the step becomes 1/7 or less of the conventional.

[0014]

According to the electromagnetically driven valve of the first aspect, since the portion of the heat conductive material exposed from the electromagnet is coated with the erosion-resistant material having high erosion resistance to oil, the oil mist on which the metal powder is deposited is provided. Even if it is exposed to the atmosphere, the heat conductive material is prevented from being eroded, and the filler in the heat conductive material does not come out, so that the wear of the metal material (for example, core or armature) by the filler is suppressed. . According to the electromagnetically driven valve of claim 2, since the erosion-resistant material is made of a material having a low influence on abrasion, for example, a non-filler material, even if the erosion-resistant material is eroded in a minute amount, a filler is not removed from the material. Since the material does not come out, the wear of the metal material (core or armature) by the filler is suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electromagnet of an electromagnetically driven valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electromagnetically driven valve according to the embodiment of the present invention, showing the principle of suppressing erosion of the heat conductive material by oil, and showing the vicinity of the heat conductive material and the erosion resistant material.

FIG. 3 is a sectional view showing the vicinity of a valve of an engine for driving an intake / exhaust valve by an electromagnetically driven valve according to an embodiment of the present invention and a driving portion thereof;

FIG. 4 is an external perspective view of an electromagnet.

FIG. 5 is a sectional view showing transfer molding of a heat conductive material of the electromagnetically driven valve according to the embodiment of the present invention in the order of steps.

FIG. 6 is a cross-sectional view showing the molding of the erosion resistant material of the electromagnetically driven valve according to the embodiment of the present invention in the order of steps.

FIG. 7 is a graph showing a comparison of the size of a step after a durability test.

FIG. 8 is a cross-sectional view of the vicinity of a heat conductive material, showing a state of erosion of the heat conductive material by oil in a conventional electromagnetically driven valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Corrosion-resistant material 2 Heat conductive material 3 Coil positioning material 4 Sliding bush 5 Permanent magnet 6 Coil 7 Inner core 8 Outer core 9 Holder 8a, 9a Slit 10 Upper die (1) 11 Lower die 12 Cylinder 13 Piston 14 Upper Mold (2) 15 Filler 16 Upper electromagnet 17 Armature 18 Lower electromagnet 19 Valve (for example, intake / exhaust valve of engine) 20, 21 Upper and lower springs 22 Electromagnetic drive valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuo Iida 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G018 AB09 AB16 CA12 DA34 DA81 FA01 GA26 3H106 DA07 DA23 DB02 DB12 DB22 DC02 DC17 EE31 EE32 GA08 KK17

Claims (2)

[Claims] 1. An electromagnetically driven valve, comprising: an electromagnet sealed between a coil and a core accommodating a coil, wherein a thermally conductive material in which a filler is dispersed in resin is provided, and the valve is driven by the electromagnetic force of the electromagnet. An electromagnetically driven valve, wherein a portion of the heat conductive material exposed from the electromagnet is coated with an erosion resistant material having high erosion resistance to oil. 2. The electromagnetically driven valve according to claim 1, wherein the erosion-resistant material is made of a material having a low influence on wear.