JP2653160B2 - solenoid valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a structure of a stator core of a fluid control solenoid valve.

2. Description of the Related Art A fluid control solenoid valve is used, for example, as an electromagnetic spill valve for opening and closing a high-pressure fuel return passage of a diesel fuel injection pump as disclosed in US Pat.

FIGS. 3 and 4 show the structure of a conventional fluid control solenoid valve.

In the figure, a housing 2 is a cylindrical body having both ends closed, and a stator core 1 is disposed in an upper half thereof. A coil bobbin 4 provided on both sides of the stator core 1 is wound with an electromagnetic coil 3 to constitute a drive unit. doing.

The stator core 1 has an E-shaped cross section as shown in FIG.
A through hole 11 is formed at the center. A fluid inflow passage 6 is formed in the lower half of the housing 2 on an extension of the through hole 11 (FIG. 3). A needle valve 5 is disposed in the inflow passage 6 so as to be vertically movable. I have. The upper end of the needle valve 5 extends into the through-hole 11, and the upper
When the electromagnetic coil 3 is not energized by being urged downward by the return spring 7 disposed therein, the inflow path 6 and the outflow path 8 provided on the outer periphery of the inflow path 6 communicate with each other. . When the electromagnetic coil 3 is energized, the needle valve 5
Receives a force upward, and the large-diameter portion 51 at the tip of the needle valve 5 contacts and closes the valve seat 61 provided on the inner peripheral wall of the inflow passage 6.

[Problems to be Solved by the Invention] By the way, in order to operate the solenoid valve at high speed, it is known that the stator core 1 should have a laminated structure in order to improve the response of magnetic flux generation to a drive current. Usually, the stator core 1 is formed by laminating a plurality of E-shaped plate members 12 (FIG. 5) and is fixed by rivets 13.

This is because, when the stator core 1 is integrally formed, a large eddy current is generated in the stator core 1 by energizing the electromagnetic coil to suppress an increase in magnetic flux. It becomes possible to make eddy current difficult to flow and to improve responsiveness.

However, in such a laminated structure, since the through hole 11 in the central portion of the stator core 1 is opened in a direction perpendicular to the direction in which the plate members 12 are stacked, processing is difficult, and a special material is used so that the plurality of plate members 12 do not fall apart. It is necessary to hold it with a jig. Furthermore, it was necessary to pay close attention so that burrs and chips generated at the time of forming the through holes 11 did not enter between the laminated plates.

Accordingly, an object of the present invention is to provide a solenoid valve which is easy to manufacture and process a stator core and has excellent performance.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a stator core is formed by laminating a plurality of plate members, and the thickness of the plate member at the center where the hole is located is set at the periphery. It is formed thicker than the plate material.

[Operation] In the above configuration, the thickness of the plate material at the center where the holes are located is made thicker than the thickness of the plate materials at the peripheral portions, so that the holes can be easily formed, and burrs and chips are generated between the plate materials. Penetration is also prevented. Moreover, since only the central plate material is made thicker, a decrease in performance is suppressed.

Embodiment An embodiment of the present invention will be described below with reference to FIG. The figure shows a stator core 1 used in the solenoid valve of the present invention, and other structures are the same as those of the conventional solenoid valve shown in FIG.

In the figure, a stator core 1 is formed by laminating a plurality of metal plates 15 each having the same shape as the plate 14 and a smaller thickness on both sides of a thick E-shaped metal plate 14.
The plate members 14 and 15 are fixed at two places on the plate surface with rivets 13, and the plate member 14 at the center has a through hole 11 extending vertically in the center.

When manufacturing the stator core 1, first, a through hole 11 is formed in the center of a thick plate material 14. Then plate
Place a predetermined number of thin plate materials 15 on both sides of 14 and rivet
Fix with 13. As described above, the thickness of the plate member 14 at the central portion is formed to be larger than the diameter of the through hole 11, and a hole is formed in the plate member 14 in advance, and the laminate is formed. This eliminates the need to use a special jig. , Processing is easy. In addition, there is no possibility that burrs and chips will enter between the plate members.

At this time, the thickness of the plate 14 at the center does not necessarily need to be greater than the diameter of the through-hole 11, and the plate 14 at the center may be thicker than the plate 15 at the periphery. Central plate
When the thickness of the plate 14 increases, the gap into which burrs and chips enter is reduced by that much, and processing becomes much easier as compared with the conventional structure, so that the object of the present invention is sufficiently achieved.

Incidentally, increasing the thickness of the plate material forming the stator core 1 generally leads to a decrease in responsiveness due to an increase in eddy current as described above, and there is a concern that the performance of the solenoid valve may be reduced. However, in the stator core 1 having the above-described structure, it has been confirmed that even if the thickness of the central plate member 14 is increased, the performance is hardly affected. The reason is described below.

In a solenoid valve using a laminated stator core,
Machining the through hole 11 in the center of the stator core 1 reduces the effective magnetic pole area, and lowers the attraction force and reduces efficiency as compared with the case where the through hole 11 is not provided. This is because, in the laminated core, the magnetic flux flows well only inside one sheet material, and has a property that it is difficult to flow between the sheet materials.
The magnetic flux flowing through the central plate 14 (FIG. 2) where the plate is divided by the through hole 11 is much smaller than the peripheral plate 15 originally.

Here, the magnitude of the eddy current generated when the magnetic flux changes is generally proportional to the change rate of the magnetic flux density. Central plate
When examining the eddy current generated in 14, the rate of change of the magnetic flux density in the central portion 141 of the plate 14 is almost the same as the magnetic flux density of the plate 15 in the peripheral portion, but by forming the through hole 11 in this portion, As the plate width becomes smaller, the resistance increases and eddy currents hardly flow. Further, since the magnetic flux density is smaller at both side portions 142 of the plate member 14 and the rate of change of the magnetic flux density is lower, the generated eddy current is extremely small. Therefore, even if the thickness of the central plate member 14 is increased, the generated eddy current does not greatly increase, and high responsiveness can be expected. This result has been confirmed by experiments.

In the above embodiment, the hole for accommodating the spring is a through-hole, but need not be a through-hole.

[Effects of the Invention] As described above, in the solenoid valve of the present invention, the stator core has a laminated structure, and the thickness of the plate at the center where the hole for storing the spring is located is larger than the thickness of the plate at the periphery. Therefore, drilling can be easily performed. Further, since no burrs or chips enter between the plate materials, post-processing such as deburring is easy, and the response is excellent.

[Brief description of the drawings]

1 and 2 are overall perspective views of a stator core showing one embodiment of the present invention, FIG. 3 is an overall sectional view of a conventional solenoid valve, and is a sectional view taken along line III-III of FIG. 4, and FIG. IV-IV in Fig. 3
FIG. 5 is an overall perspective view of a conventional stator core. DESCRIPTION OF SYMBOLS 1 ... Stator core 11 ... Through-hole (hole) 14 ... Central plate material 15 ... Peripheral plate material 3 ... Electromagnetic coil 5 ... Needle valve (valve element)

Continuation of the front page (56) References JP-A-64-15956 (JP, A) JP-A-2-98905 (JP, A) JP-A-63-168376 (JP, U)

Claims (1)

(57) [Claims] 1. A stator core, an electromagnetic coil wound around the stator core, a valve element driven by the electromagnetic coil to open and close a flow path, and a valve element formed at a central portion of the stator core for urging the valve element. An electromagnetic valve having a hole for accommodating a spring, wherein the stator core is formed by laminating a plurality of plate members, and the plate thickness of the central portion where the hole is located is larger than the plate thickness of the peripheral portion. An electromagnetic valve characterized by being formed thick.