JP2002373807A - Method of bonding magnetic body to non-magnetic body, solenoid valve and magnetic induction type sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a moving core having a magnetic part and a non- magnetic part alternately formed in a solenoid valve with high reliability in strength and with high accuracy. SOLUTION: In a bonded body capable of being used as a moving core of a solenoid valve, a non-magnetic body 2 is coaxially sandwiched between magnetic bodies 3, 4. This bonded body is manufactured by putting the magnetic bodies 3, 4 and the non-magnetic body 2 in this state between current-passing electrodes 73, 76 of a current-passing bonding unit 70 of a current-passing bonding device 7, by passing a DC current or a pulse current with a predetermined pressure applied thereto, and then by heating and leaving them in a predetermined heating state for a predetermined time by a heat-treating machine 80. This can provide a moving core in which the magnetic bodies and the non- magnetic body are bonded to each other at their bonding faces at a bonding strength equal to their mother strengths.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining a magnetic material and a non-magnetic material, which can join a magnetic material and a non-magnetic material with a joining strength substantially equal to the strength of a base material. Further, the present invention provides a solenoid valve having a movable core in which a magnetic portion and a non-magnetic portion are alternately formed in an axial direction, and a magnetic valve having a detection rod in which a magnetic portion and a non-magnetic portion are alternately formed. It relates to an inductive sensor.

[0002]

2. Description of the Related Art Conventionally, solenoid valves have been frequently used in various fields for controlling the flow rate of fluids such as liquids and gases. The solenoid valve includes a solenoid composed of an electromagnetic coil and a movable iron core movable in the axial direction by controlling energization of the electromagnetic coil, and a valve body attached to the tip of the movable iron core. As the movable core, a configuration in which magnetic portions and non-magnetic portions are alternately formed at a predetermined pitch along the axial direction is known, and by using such a movable core, the axis of the movable core is known. The position in the direction can be accurately controlled, and the position can be controlled in multiple stages.

On the other hand, a magnetic induction type sensor is known as a sensor for detecting the moving position of a reciprocating object. In this type of sensor, a detection rod that reciprocates linearly is directed in the axial direction thereof. A magnetic portion and a non-magnetic portion are formed, and the detection rod is moved through ring coils arranged at a constant pitch, and a movement position of the detection rod is detected based on an induced current generated by each ring coil. I have.

Here, a movable iron core of a solenoid and a detection rod of a magnetic induction sensor having such a structure in which magnetic portions and non-magnetic portions are alternately formed are manufactured as follows. That is, it is manufactured by manufacturing a columnar magnetic material and a non-magnetic material having a certain width, and joining them coaxially by welding or using an adhesive.
Instead, a shaft member is manufactured from a magnetic material, and is demagnetized at a constant pitch along the axial direction by high-frequency heating, thereby manufacturing magnetic parts and nonmagnetic parts alternately arranged in the axial direction. are doing.

[0005]

However, when the welding method or the adhesive bonding method is employed, the joining of the magnetic material and the non-magnetic material is incomplete, and it is difficult to secure a sufficient joining strength. However, there is a problem that the reliability of the manufactured movable iron core and the detection rod is low.

The method of forming a non-magnetic portion on a shaft member made of a magnetic material is not manufactured by joining a plurality of parts. Cannot be formed accurately in the region where In particular, the boundary between the magnetic portion and the non-magnetic portion cannot be formed linearly in the circumferential direction. As a result, the positioning accuracy of the movable iron core of the solenoid is reduced, and the detection accuracy of the magnetic induction sensor is reduced, which is not desirable.

Therefore, if the magnetic material and the non-magnetic material can be firmly joined over the entire joining surface, the reliability is high and the
This is preferable because the movable iron core and the detection rod can be manufactured with high accuracy.

In order to perform such bonding, for example,
A hot press joining method in which a direct current is passed between members to be joined under a predetermined pressure, or a discharge plasma sintering method (SP) in which a direct current pulse is passed between them to perform sintering.
It is conceivable to employ a joining method utilizing the principle of S).

However, in the latter joining method utilizing the SPS technology, the members to be joined need to be put in a graphite mold and joined in the mold, and the joining operation is complicated. There are drawbacks such as a great limitation on the shape and dimensions of the joining members, and furthermore, there is a drawback that sufficient joining strength cannot be obtained. As a joining method utilizing the principle of the spark plasma sintering method, see Japanese Patent Application Laid-Open No. 11-1585.
However, in the method disclosed here, it is necessary to roughen the joint surface, and the method cannot be used for joining the mirror-finished joint surface. There is a disadvantage that a high joining strength cannot be obtained.

[0010] On the other hand, when the former hot press bonding method is used for bonding bulk materials, it takes time and cost, but has the disadvantage that it is difficult to obtain sufficient bonding strength.

[0011] The object of the present invention is to solve the above problems.
An object of the present invention is to propose a joining method of a magnetic material and a non-magnetic material that can surely join a magnetic material and a non-magnetic material with a joining strength about the same as the base material strength thereof.

Another object of the present invention is to provide a solenoid valve provided with a movable core in which magnetic parts and non-magnetic parts manufactured by using this joining method are alternately formed.

A further object of the present invention is to propose a magnetic induction type sensor provided with a detection rod formed by using this method, in which a magnetic portion and a non-magnetic portion are alternately formed.

[0014]

In order to solve the above-mentioned problems, the present invention relates to a method for joining a magnetic material and a non-magnetic material, the method comprising: Form a state of butting by pressing force, while maintaining this pressing state, the magnetic material and the non-magnetic material,
The method is characterized in that a direct current and / or a pulse current is passed to temporarily join the magnetic material and the nonmagnetic material, and the magnetic material and the nonmagnetic material in the temporarily joined state are heat-treated at a predetermined ambient temperature. And

Here, it has been confirmed that the pressing force is desirably 50 megapascal or less. Also,
It was also confirmed that the heat treatment was desirably performed in an inert atmosphere.

It has been confirmed that the temperature of this heat treatment is desirably in a temperature range of 85% or less of the lowest melting point of the members to be joined.

Next, the magnetic material and the non-magnetic material are
It can be a rod-shaped solid part or a rod-shaped hollow part.

In this case, the magnetic portion and the non-magnetic portion are alternately formed by joining at least one magnetic body and at least one non-magnetic body alternately in the axial direction thereof. Shaft parts can be obtained.

Here, a plurality of sets of the magnetic material and the non-magnetic material to be joined are arranged in the axial direction with a partition plate made of carbon paper or the like interposed therebetween. If the non-magnetic material is temporarily joined at the same time, a joined body composed of many sets of the magnetic material and the non-magnetic material can be obtained at the same time.

Further, a plurality of sets in which the magnetic material and the non-magnetic material to be joined are arranged in the axial direction are arranged in a plurality of rows, and in this state, the magnetic material and the non-magnetic material of each set are temporarily joined simultaneously. However, it is possible to simultaneously obtain a joined body composed of a large number of sets of magnetic and non-magnetic materials.

Further, in this case, it is desirable that the magnetic and non-magnetic members to be joined are maintained in a state of being arranged in the axial direction by a cylindrical jig made of carbon, ceramic or the like.

Next, according to the present invention, there is provided an electromagnetic valve having a movable core in which a magnetic portion and a non-magnetic portion are alternately formed in an axial direction, wherein the magnetic portion and the non-magnetic portion of the movable core are It is characterized by being manufactured using the above-described method of joining a magnetic substance and a non-magnetic substance.

On the other hand, the present invention relates to a magnetic induction type sensor having a detection rod in which a magnetic part and a non-magnetic part are formed at a predetermined interval, wherein the magnetic part and the non-magnetic part of the detection rod are as described above. It is characterized by being manufactured using a joining method of a magnetic material and a non-magnetic material.

According to the joining method of the present invention, it has been confirmed that a magnetic material and a non-magnetic material can be joined with a sufficient strength equivalent to their base material strength. Therefore, if the movable iron core is manufactured by using the joining method of the present invention, a solenoid valve having high strength reliability and high positioning accuracy can be realized. Further, if the detection rod is manufactured by using the joining method of the present invention, a magnetic induction sensor having high strength reliability and high detection accuracy can be realized.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the drawings, an example of a method for joining a magnetic material and a non-magnetic material to which the present invention is applied, and an electromagnetic valve provided with a movable iron core manufactured by the joining method will be described. An example and an example of a magnetic induction sensor having a detection rod manufactured according to the joining method will be described.

FIG. 1 shows a joined body of a magnetic material and a non-magnetic material obtained by the joining method of this embodiment. The joined body 1 of this example has a columnar shape, and a columnar nonmagnetic body 2 having a narrow width is sandwiched in the center in the direction of the axis 1a. They are coaxially joined. That is, one end face 3b of the circular end faces 3a and 3b of the magnetic body 3 and one circular end face 2a of the non-magnetic body 2 are the joining surfaces thereof, and the circular end face 4
One of the end faces 4a and 4b and the other circular end face 2b of the non-magnetic material 2 serve as a joint surface between them.

The material of the magnetic bodies 3 and 4 is SUS42
Martensitic stainless steel such as 0J2 and SC415 can be mentioned. The material of the non-magnetic material 2 is S
An austenitic stainless steel represented by US304 or the like can be given.

Next, with reference to FIG. 2, an example of an energization joining apparatus used for manufacturing the joined body 1 (in other words, used for joining the magnetic bodies 3 and 4 and the non-magnetic body 2) will be described. I do.

As shown in this figure, the current-carrying apparatus 7 of this embodiment includes a current-carrying machine 70 and a heat treatment machine 80. The energization bonding machine 70 includes a lower energization electrode 73 that is electrically insulated and fixed to the base 72 by a known method via an insulating member on the base 72, and is disposed above the base 73. A fluid pressure cylinder 74 supported on the base in a known manner, and an upper side fixed to the tip of a piston rod 75 of the fluid pressure cylinder 74 by an insulating member and electrically insulated from the piston rod 75 in a known manner. And a current-carrying electrode 76.

The fluid pressure cylinder 74 functions as a pressure device for pressing the material to be joined. As the pressurizing device, an electric motor, a screw mechanism or the like may be used instead of the fluid pressure cylinder to raise and lower the upper energized electrode. The upper and lower conducting electrodes 73 and 76 are electrically connected to a power supply 77, and the power supply 77 can supply a DC pulse current. The power supply of the power supply device 77 of this example has a voltage of 100 V or less and a current of 2000 to 5
Large current power in the range of 000A. Although the upper energizing electrode 76 is movable in this example, the lower energizing electrode 73 may be movable, or both may be movable.

Next, the heat treatment machine 80 is provided with a vacuum heat treatment furnace having a known structure. In addition, the electric welding machine 7
0 and the heat treatment machine 80 may be integrated into a device, or they may be movable. Of course, these may be arranged separately.

Next, the magnetic members 3 and 4 and the non-magnetic member 2 are joined by using the current-carrying apparatus 7 having this structure to form the joined member 1.
Will be described.

First, as shown in FIG. 2, the non-magnetic material 2 is sandwiched in the center, and the magnetic material 4 and the magnetic material 3 are superposed one on top of the other in a coaxial state. Installing.

As described above, the magnetic materials 3 and 4 and the non-magnetic material 2
Is mounted, the hydraulic cylinder 74 is driven to lower the upper energizing electrode 76 by the piston rod 75. As a result, the magnetic materials 3 and 4 and the non-magnetic material 2
Is sandwiched between the energizing electrodes 73 and 76 and is pressed by a predetermined pressing force. That is, a predetermined pressing force is applied between the joining surfaces 3b and 2a and between the joining surfaces 2b and 4a. The pressing force varies depending on the material of the member, but may be 50 MPa or less.

As a result, the joining surfaces are joined to each other. Although the exact principle of this bonding is not always clear, it is considered that bonding is performed by generation of discharge plasma between bonding surfaces, thermal diffusion effect by Joule heat, electrolytic diffusion effect by electric field, and the like.

Here, even if only a DC current of a predetermined value is applied to the magnetic bodies 3, 4 and the non-magnetic body 2, or if both a DC current and a pulse current are simultaneously applied, the joining surfaces are joined to each other. It was confirmed that the obtained state could be formed.

The state in which the joining surfaces are joined in this way is not yet complete in terms of joining strength. Therefore, this joined state is called a temporary joined state, and the magnetic bodies 3, 4 and the non-magnetic body 2 in the temporarily joined state are called a temporary joined body.

The temporary joined body is heat-treated in a heat treatment furnace of the heat treatment machine 80. The heat treatment temperature and time vary depending on the material and size of the member. By performing heat treatment,
The joining between the joining surfaces in the temporary joining state becomes perfect and becomes a complete joined body. That is, the bonding strength between the bonding surfaces becomes a value comparable to the material strength of the member.

Through the heat treatment as described above, the joined body 1 shown in FIG. 1 is obtained. In the joined body 1, since the magnetic bodies 3, 4 and the non-magnetic body 2 are joined alternately, the magnetic body and the non-magnetic body 2 are joined together as compared with the case where the magnetic body is partially demagnetized by high-frequency heating. The boundaries between the non-magnetic materials are clear, and are linear in the circumferential direction. Also, unlike conventional welding, adhesive bonding, and the like, the bonding surfaces are bonded with strong bonding strength about the same as the strength of the base material, so that the strength reliability is high. For this purpose, cutting may be performed before joining. For example, it is also possible to perform cutting after forming the joined body 1 to obtain a final product.

(Another example of the joined body) Here, in the above example, one magnetic body 3, 4
Are joined. As the structure of the joined body,
As shown in FIGS. 3A to 3C, a configuration in which two non-magnetic members 12 and 13 are joined on the upper and lower sides of a magnetic member 11, two magnetic members 14 and 15 and two non-magnetic members 16 and 17 are alternately joined, and a large number of magnetic materials and non-magnetic materials are alternately connected. In any case, the joining method of the present invention can be applied. The joining surface is not orthogonal to the axial direction, and can be applied even if it is inclined.

The shape of the magnetic or non-magnetic material is as follows.
In addition to a cylinder, a cylinder as shown in FIG. Further, a rectangular cross section, a polygonal cross section, or the like can be used, and there is no particular limitation on the cross sectional shape. Although only a simple shape is shown in FIG. 3, it is desirable to form the shape for positioning or the like so as to obtain a desired shape by actual joining. To prevent misalignment, for example, a ring-shaped portion may be fitted.

(Another Example of Joining Method) Next, FIG. 4 shows an example of a joining method capable of joining a large number of joined bodies 1 at the same time. In the current joining machine 70A shown in FIG. 4A, a large number of sets of the magnetic bodies 3, 4 and the non-magnetic bodies 2 can be mounted between the upper and lower energizing electrodes 76, 73. In this way, a large number of joined bodies 1 can be obtained at the same time.

Further, an electric welding machine 70B shown in FIG.
Then, between the upper and lower energizing electrodes 76 and 73, a large number of sets, in the illustrated example, a set composed of the magnetic bodies 3 and 4 and the non-magnetic
The sets (1A, 1B, 1C) are stacked coaxially, and a partition plate 2 made of carbon paper or the like is provided between the sets 1A, 1B, 1C so that they are not joined.
1 is plugged in. Further, many rows of such three sets are mounted between the upper and lower conducting electrodes 76 and 73. In this way, more joined bodies 1 can be obtained at the same time.

Here, when a large number of sets composed of the magnetic members 3 and 4 and the non-magnetic member 2 are arranged vertically, a cylindrical shape as shown in FIG. It is desirable to use the holding jig 22 described above. The holding jig 22 is made of carbon or ceramic, and the magnetic members 3 and 4 and the non-magnetic member 2 can be inserted into a through hole 23 formed at the center.

(Example of Solenoid Valve) Next, FIG. 5 shows an example of a solenoid valve having a movable core in which magnetic portions and non-magnetic portions are alternately formed by the above-described joining method. As shown in this drawing, the overall configuration of the solenoid valve 30 is the same as that generally known, and a valve 32 for opening and closing a fluid passage 31 and moving the valve 32 in the opening and closing direction. And a solenoid 33 for the
Is a movable iron core 34 to which the valve element 32 is attached at the tip.
And a ring-shaped electromagnetic coil 35 surrounding the movable iron core 34 coaxially. The movable iron core 34
Along with the axial direction, there is provided a shaft portion in which magnetic portions and non-magnetic portions are alternately formed. The movable iron core 34 having such a configuration is obtained by joining the magnetic material and the non-magnetic material by the above-described joining method. It is manufactured.

(Example of Magnetic Induction Type Sensor) FIG. 6 shows an example of a magnetic induction type sensor provided with a detection rod in which magnetic portions and non-magnetic portions are alternately formed by the above-described joining method. As shown in this figure, the magnetic induction type sensor 40 includes a detection rod 41 that moves linearly reciprocally, a ring-shaped electromagnetic coil group 42 arranged at a constant pitch surrounding the outer circumference, and a movement of the detection rod 41. , A signal processing circuit 43 for generating A and B signals based on the current generated in the electromagnetic coil group 42. Detection rod 41
The magnetic rods 44 and the non-magnetic parts 45 are alternately formed at regular intervals. The detection rod 41 having such a configuration is manufactured by joining a magnetic substance and a non-magnetic substance by the above method. is there.

[0047]

As described above, according to the joining method of the present invention, the magnetic material and the non-magnetic material are brought into contact with each other at their joining surfaces, and the direct current and / or Alternatively, temporary bonding is performed by passing a pulse current, and then heat treatment is performed.

According to the joining method of the present invention, a magnetic material and a non-magnetic material can be joined with a sufficient strength equivalent to the strength of their base material. Therefore, by manufacturing a movable core in which magnetic portions and non-magnetic portions in an electromagnetic valve are alternately formed by using the joining method of the present invention, it is possible to realize an electromagnetic valve having high strength reliability and high positioning accuracy. Also,
By using the bonding method of the present invention to manufacture a detection rod in which a magnetic portion and a non-magnetic portion in a magnetic induction sensor are alternately formed, a magnetic induction sensor having high strength reliability and high detection accuracy can be realized. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a joined body manufactured by a joining method to which the present invention is applied, and an exploded perspective view thereof.

FIG. 2 is a schematic configuration diagram illustrating an example of a current-carrying apparatus for performing the method of the present invention.

FIG. 3 is an explanatory view showing an example of a joined body that can be manufactured by the joining method of the present invention.

FIG. 4 is an explanatory view showing an example of an electric welding machine capable of manufacturing a large number of joined bodies at the same time.

FIG. 5 is an explanatory view showing an example of a solenoid valve having a movable iron core manufactured by the method of the present invention.

FIG. 6 is an explanatory view showing an example of a magnetic induction type sensor having a detection rod manufactured by the method of the present invention.

[Description of Signs] 1 bonded body 2 non-magnetic material 2a, 2b bonding surface 3, 4 magnetic material 3b, 4a bonding surface 7 conductive bonding device 70 conductive bonding machine 80 heat treatment machine

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[Procedure amendment]

[Submission date] July 4, 2001 (2001.7.4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG. 5

FIG.

FIG. 2

FIG. 3

FIG. 6

FIG. 4

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 7/16 RF term (Reference) 3H106 DA23 DA26 DB02 DB12 DB22 DB32 DC02 DD04 EE07 EE29 GA17 JJ03 JJ05 5E048 AB01 AD01 CA07

Claims (12)

[Claims] 1. A method for joining a magnetic material and a non-magnetic material, comprising: forming a state in which a joining surface of the magnetic material and a joining surface of the non-magnetic material abut against each other with a predetermined pressing force; A DC current and / or a pulse current is applied to the magnetic body and the non-magnetic body to temporarily join the magnetic body and the non-magnetic body, and the magnetic body and the non-magnetic body in the temporarily joined state are ,
A method for joining a magnetic material and a non-magnetic material, wherein a heat treatment is performed at a predetermined atmospheric temperature. 2. The method according to claim 1, wherein the pressing force is set to 50 megapascals or less. 3. The method according to claim 1, wherein the heat treatment is performed in an inert atmosphere. 4. The method according to claim 1, 2 or 3, wherein the temperature of the heat treatment is set to 8 of the lowest melting point of the member to be joined.
A method for joining a magnetic material and a non-magnetic material, wherein the temperature range is 5% or less. 5. The magnetic material according to claim 1, wherein the magnetic material and the non-magnetic material are a rod-shaped solid part or a rod-shaped hollow part. How to join magnetic materials. 6. The magnetic material and the non-magnetic material according to claim 5, wherein at least one magnetic material and at least one non-magnetic material are alternately joined in their axial direction. Joining method. 7. The method according to claim 6, wherein the magnetic material and the non-magnetic material are coaxially bonded. 8. The method according to claim 6, wherein a plurality of sets of the magnetic material and the non-magnetic material to be joined are arranged in the axial direction with a partition plate made of carbon paper or the like sandwiched therebetween. A method of temporarily joining said magnetic material and said non-magnetic material simultaneously. 9. The magnetic material and the non-magnetic material according to claim 6, wherein a plurality of sets in which the magnetic material and the non-magnetic material to be joined are arranged in the axial direction are arranged in a plurality of rows. At the same time, the magnetic material and the non-magnetic material are joined together temporarily. 10. The magnetic device according to claim 6, 7, 8 or 9, wherein the magnetic material and the non-magnetic material to be joined are kept aligned in the axial direction by a cylindrical jig made of carbon, ceramic, or the like. A method for joining a magnetic material and a non-magnetic material. 11. A solenoid valve provided with a movable core in which a magnetic portion and a non-magnetic portion are alternately formed in the axial direction, wherein the magnetic portion and the non-magnetic portion of the movable iron core are arranged in a manner similar to the above. A solenoid valve manufactured by using the method for joining a magnetic substance and a non-magnetic substance according to any one of claims 1 to 4. 12. A magnetic induction type sensor having a detection rod in which a magnetic part and a non-magnetic part are formed at a predetermined interval, wherein the magnetic part and the non-magnetic part of the detection rod are in accordance with claim 6 or 7. A magnetic induction type sensor manufactured using the method for joining a magnetic substance and a non-magnetic substance described in the above.