JP2002343658A - Reforming method and apparatus magnetic circuit member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of a curing layer near a reforming section in a method for reforming to a non-magnetic material partially, by making a high-energy-density beam irradiated on the magnetic circuit member of a magnetic material, and by supplying an austenite generating element to a fused irradiation site. SOLUTION: Overheating for heating a wide range, including a movement locus K of an illumination site P of a magnetic circuit member W to a temperature lower than the melt temperature of the magnetic circuit member W, is started before the irradiation of the high-energy density beam L is completed, thus reducing a cooling speed due to heat conduction at a portion being fused by the high-energy density beam L. The high-energy density beam may be started, immediately after the overheating is completed. Preferably, overheating is performed by a high-frequency heating coil 30. The high-energy density beam should be set to a laser beam, and the austenite generation element is preferably supplied by a wire supply apparatus 25 for supplying a wire 26, for reformation containing such elements to the fused portion of the magnetic circuit member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reforming method and a reforming apparatus for modifying a part of a magnetic circuit member made of a magnetic material such as a sleeve of an electromagnetic valve into a weak magnetic material or a non-magnetic material.

[0002]

2. Description of the Related Art As a method of modifying a sleeve of such an electromagnetic valve, there is a technique disclosed in, for example, JP-A-2000-21628. This is because the laser beam is irradiated and melted while supplying the austenite forming element to the part corresponding to the magnetic gap of the ferromagnetic sleeve, and the part is alloyed to partially weaken or demagnetize it. This is a method for reforming the sleeve of the solenoid valve. According to this, as shown in FIG. 1, a modified portion Wb made of nonmagnetic austenite is generated at a portion corresponding to the magnetic gap of the sleeve W made of the ferromagnetic base material Wa.

[0003]

However, in the above-mentioned prior art, since the heating and melting by the laser beam is local, the vicinity of the heating portion after the passage of the laser beam is rapidly cooled by heat conduction to the surroundings. . For this reason, even if the manufactured sleeve W is made of low-carbon steel, the heat-affected zone Wc of the base material Wa at the boundary with the modified zone Wb (see FIG. 1)
Is hardened to form a hardened layer. In the sleeve W of such a solenoid valve, the outer diameter and the inner diameter of the inner hole Wd are finished by cutting, but especially the inner diameter to which the spool is fitted requires strict accuracy. Cutting is very difficult.

In order to solve this problem, it is necessary to anneal the hardened layer generated in the heat-affected zone Wc. However, if the anneal is performed by furnace annealing, the entire sleeve W is softened. There is a problem that the mounting portion buckles and causes oil leakage. In order to solve such a problem, the reforming section W
(b) To anneal only the hardened layer of the heat-affected zone Wc on both sides, a high-frequency heating device requires a partial annealing step of heating only the vicinity of the reformed zone Wb, which requires another equipment and heating energy. There is a problem that the manufacturing cost increases. An object of the present invention is to solve each of these problems.

[0005]

In order to achieve the above object, a method of modifying a magnetic circuit member according to the present invention comprises: irradiating a part of a magnetic circuit member made of an iron-based magnetic material with a high energy density beam; A magnetic circuit member that melts and moves an irradiation site on a magnetic circuit member and supplies an austenite-forming element to the melted portion to modify the vicinity of the movement locus of the irradiation site into a weak magnetic material or a non-magnetic material The method according to any one of the first to third aspects is characterized in that a wide range including a movement locus of an irradiation part of the magnetic circuit member is preheated.

[0006] In the reforming method of the magnetic circuit member according to the present invention, the temperature of the preheating is lower than the melting temperature of the magnetic circuit member, and the temperature of the heat affected zone of the magnetic circuit member adjacent to the melted portion is reduced to the critical cooling rate. It is preferable that the temperature be such that the cooling rate becomes as follows.

A method for modifying a magnetic circuit member according to the present invention comprises:
It is preferable to start irradiation of the high energy density beam immediately after the end of the preheating.

The high energy density beam in the magnetic circuit member reforming method according to the present invention is preferably a laser beam.

In the method for modifying a magnetic circuit member according to the present invention, it is preferable that the extra heating is performed by a high-frequency heating coil.

[0010] The magnetic circuit member reforming apparatus according to the present invention is a magnetic circuit member reforming apparatus for reforming a part of a base material made of an iron-based magnetic material into a weak magnetic material or a non-magnetic material.
A beam irradiation device that irradiates a part of the magnetic circuit member with a high energy density beam to melt the irradiated portion, an irradiation portion moving device that grips the magnetic circuit member and moves the irradiated portion on the magnetic circuit member, An element supply device that supplies an austenite-forming element to the melted portion of the magnetic circuit member, and a wide range including the movement locus of the irradiation site on the magnetic circuit member is preheated to a temperature lower than the melting temperature of the magnetic circuit member Characterized in that it is provided with an extra heating device.

[0011] The residual heating device of the magnetic circuit member reforming apparatus according to the present invention is preferably a high-frequency heating coil.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below of a method and an apparatus for reforming a magnetic circuit member according to the present invention with reference to the embodiments shown in FIGS. In this embodiment, the present invention is applied to a part of a sleeve (magnetic circuit member) of an electromagnetic valve which is made austenite to be partially demagnetized or weakly magnetized (hereinafter simply referred to as nonmagnetization). is there. As shown in FIG. 1, the sleeve W has a cylindrical shape having a large-diameter portion Wd on the root side, and an inner hole We for slidably inserting a plunger.
Is formed from the large-diameter portion Wd side, and a portion before the closed end is a portion corresponding to the magnetic gap, and a non-magnetized cylindrical reformed portion Wb is formed in this portion. It is.

First, a description will be given of a magnetic circuit member reforming apparatus according to this embodiment. As shown mainly in FIG. 2, the reforming apparatus includes an index table 15 provided with a pair of chuck devices (irradiation site moving devices) 16 and a member supply / extraction member provided at a detachable portion A which is one side thereof. Apparatus 1
0, a laser condensing head (beam irradiation device) 20, a wire supply device (element supply device) 25, and a high-frequency heating coil (excess heating device) 30 arranged in the processing section B opposite to the detachable section A. Things.

As shown mainly in FIG. 2, an index table 15 rotatably supported around a vertical rotation axis O1 has a pair of chuck devices 16 on its upper surface, which are back-to-back with each other and have the same radius from the rotation axis O1. It is arranged so that it may become a direction position. The two chuck devices 16 have the same structure, and each has a collet chuck portion 16a rotatably supported around a common rotation axis O2 orthogonal to the rotation axis O1. Collet chuck 1
6a coaxially grips the large-diameter portion Wd of the sleeve W, is rotated around a rotation axis O1 by a rotation and axis feed servomotor (both not shown) built in the chuck device 16, and moves forward and backward in the axial direction. It is supposed to be. Each chuck device 16 is alternately indexed into a detachable unit A and a processing unit B by the index table 15. The member supply and unloading device 10 includes a hopper, a part feeder, and a transfer hand that handle the sleeve W. The collet chuck 16a grips the sleeve W that has not been subjected to the reforming process.

As shown mainly in FIG. 3, the sleeve W gripped by the collet chuck portion 16a of the chuck device 16, indexed by the processing portion B, and moved outward in the axial direction of the rotation axis O1 by the axis feed servomotor. A laser condensing head (beam irradiation device) 20 is disposed at a position directly above the center in the width direction and the diameter direction of the portion to be the cylindrical reformed portion Wb. The laser beam (high energy density beam) L supplied from the YAG laser oscillator 21 to the laser focusing head 20 via the optical fiber 22 is located at one point on the center in the width direction of the portion to be the modified portion Wb of the sleeve W. To melt the irradiated portion P. Since the sleeve W is rotated by the chuck device 16 during this irradiation, the movement trajectory K of the irradiation site P on the surface of the sleeve W becomes a circle along the circumferential direction as shown in FIG. The portion melted by the laser beam L also extends along the movement trajectory K. The diameter of the spot of the laser beam L irradiated onto the sleeve W is, for example, about 0.6 mm, and the diameter of the melting range by this is about 1 mm. After passing through the laser beam L, the melted portion is rapidly cooled by heat conduction to the surroundings and solidified.

As shown in FIG. 2 and FIG.
At a portion rearward in the circumferential direction with respect to the portion melted by the laser beam L and not yet solidified, a wire for reforming 2 containing an austenite-forming element is supplied from the wire supply device 25.
6 is supplied, whereby the portion to be the modified portion Wb of the sleeve W is austenitized and reformed to non-magnetic or weakly magnetic. The austenite forming element is, for example, nickel, manganese, cobalt, carbon, nitrogen, or the like. The component and supply amount of the reforming wire 26 are, for example, 28% Ni equivalent and 8% Cr equivalent of the modified portion Wb. It is determined as follows.

The high-frequency heating coil 30 surrounds the lower half of the sleeve W so as to
Is provided at a position facing the beam irradiation device 20 with the. The high-frequency heating coil 30 includes a high-frequency oscillator 3
1 is provided, whereby a wide range including the movement trajectory K of the sleeve W is preheated to a temperature lower than the melting temperature of the sleeve W.

Next, the reforming method according to this embodiment will be described. The diameter of the modified portion Wb generation portion of the sleeve W of this embodiment is 10 mm, and the base material Wa is S15C. The rotation speed of the sleeve W by the chuck device 16 is 60 rpm, and the width of the high-frequency heating coil 30 is 1
0 mm.

On the side of the attaching / detaching portion A, the sleeve W whose reforming portion Wb has not been demagnetized is placed in the collet chuck portion 16.
The chuck device 16 gripped by the a is indexed from the attaching / detaching portion A to the processing portion B by the operation of the index table 15 in a state where the collet chuck portion 16a is retracted by the axis feed servomotor, and is again returned to the collet chuck portion 16a.
3, the center of the sleeve W in the width direction and the diameter direction of the portion to be the modified portion Wb is located directly below the beam irradiation device 20 and the lower half thereof is surrounded by the high-frequency heating coil 30 as shown in FIG. Position. In this state, the beam irradiation device 20 and the high-frequency heating coil 3
From 0, the discharge of the shielding gas (inert gas such as nitrogen) is started, the rotation servomotor of the chuck device 16 is operated to rotate the sleeve W, and the output from the high-frequency oscillator 31 is applied to the high-frequency heating coil 30 for 1 second. Output, a wide range (about 10 mm which is the same as the width of the high-frequency heating coil 30) including the movement locus K of the irradiation area P of the laser beam L to be performed next is lower than the melting temperature of the magnetic circuit member, and Preheating is performed until the temperature of the heat-affected zone of the adjacent magnetic circuit member becomes a cooling speed at which the martensitic transformation occurs and the cooling speed becomes lower than the critical cooling speed at which quenching and hardening is performed, for example, about 700 ° C.

Immediately after the output of the high-frequency oscillator 31 is stopped, the YAG laser oscillator 21 is operated while the sleeve W is continuously rotated by the chuck device 16 to irradiate the laser beam L from the beam irradiation device 20 onto the sleeve W. To melt the irradiated portion P and a part of the movement trajectory K on the rear side in the circumferential direction with respect to the irradiated portion P, and supply the reforming wire 26 from the wire feeding device 25 to the melted portion to supply the sleeve W And after 5 seconds, the reforming wire 2
6 is stopped, the YAG laser oscillator 21 is stopped, the irradiation of the laser beam L is stopped, and the rotation of the chuck device 16 is stopped. As a result, the modified portion Wb of the sleeve W is austenitized and demagnetized.

One chuck device 16 holding the sleeve W that has not been subjected to the reforming process is moved from the attaching / detaching portion A to the processing portion B.
At the same time, the other chuck device 16 holding the sleeve W in which the reforming section Wb has been demagnetized by the previous reforming process is indexed from the processing section B to the attaching / detaching section A.
The reformed sleeve W held by the other chuck device 16 is subjected to the above-described reforming process in the processing section B, and the member supply / extraction device 10 in which the reforming is not performed in the attaching / detaching section A is performed. Is replaced with the sleeve W inside. When the reforming process in the processing section B is completed, the chuck devices 16 of the attaching / detaching section A and the processing section B are immediately replaced by the index table 15, and the next sleeve W is subjected to the reforming processing in the processing section B. .

In this embodiment, a wide range including the movement trajectory K of the irradiation site P of the laser beam L is preheated to about 700 ° C., and the periphery of the portion heated and melted by the laser beam L in this manner. Since the temperature of the portion is high, the cooling rate of the melted portion due to heat conduction is low. Therefore, the heat affected zone Wc of the base material Wa, which is the boundary with the portion demagnetized by the modification, is not quenched, and a hardened layer does not occur. Therefore, processing of the sleeve W after demagnetizing the portion corresponding to the magnetic gap of the sleeve W becomes easy.

FIG. 4 is a diagram showing the results of measurement of the hardness of the heat-affected zone Wc of the sleeve W in which the reformed portion Wb is made non-magnetic according to this embodiment, in comparison with the above-described conventional technology. The position of the horizontal axis is taken in the axial direction with reference to the boundary with the reforming portion Wb, and the measurement point is a position at a depth of 0.1 mm from the surface. As is clear from this figure, the Vickers hardness of the heat-affected zone Wc at a position 1.5 mm or more away from the boundary with the reformed zone Wb in the axial direction is the one modified by the present invention and the one modified by the conventional technique. Although the hardness in the vicinity of the boundary portion of the reformed portion Wb is not higher than the value according to the present invention of Hv312, the value according to the prior art is Hv467, and according to the present invention, the hardness of the reformed portion Wb is smaller than that of the modified portion Wb. This shows that the hardness near the boundary can be considerably reduced.

Since the additional heating for preventing the formation of the hardened layer is performed simultaneously with the demagnetization of the portion of the sleeve W corresponding to the prior art, no other equipment is required except for the high-frequency heating coil 30, and the processing is performed. Since the number of steps does not increase, and as a whole, the increase in heating energy during processing is very small, the increase in manufacturing cost is very small.

In this embodiment, while the processing portion B is performing the reforming process for demagnetizing the portion corresponding to the magnetic gap of the sleeve W, the attaching / detaching portion A is gripped by the other chuck device 16. Since the sleeve W having been subjected to the reforming process has been replaced with the sleeve W having not been subjected to the reforming process, if the reforming process of the sleeve W in the processing section B is performed, both the chuck devices 16 are immediately replaced. Index processing is performed using the index table 15 so that the sleeve W can be immediately modified in the processing section B. Therefore, the operating efficiency in the processing section B can be increased and the manufacturing cost can be reduced.

In this embodiment, the irradiation of the laser beam L is started immediately after the end of the preheating by the high-frequency heating coil 30, so that the increase in the temperature of the sleeve W due to the preheating is achieved. Only the output of the YAG laser oscillator 21 can be reduced. This gives Y
Since the AG laser oscillator 21 only needs to have a small output, the equipment cost can be reduced. However, the present invention is not limited to this, and may be implemented such that the extra heating by the high-frequency heating coil 30 is performed in parallel with the irradiation with the laser beam L or until after the end of the irradiation with the laser beam L, Even in such a case, an effect is obtained that the cooling rate due to the heat conduction of the portion melted by the laser beam L is reduced and the heat affected zone Wc is prevented from being hardened by quenching.

In this embodiment, a laser beam is employed as a high energy density beam for locally irradiating and melting the sleeve W. According to this, it is not necessary to maintain the atmosphere in a vacuum, so that there is no need to add a laser beam. Equipment is simplified.
However, the present invention is not limited to this, and may be implemented by using an electron beam or the like as the high energy density beam.

In this embodiment, the extra heating is performed by the high-frequency heating coil 30. According to this, heating can be performed in a free atmosphere, so that deterioration of the material of the sleeve W due to oxidation or the like can be easily prevented. is there. However, the present invention is not limited to this, and it is also possible to carry out extra heating by using a gas burner or the like. This additional heating is performed in a state where the sleeve W is retracted by the chuck device 16, and after the completion of the additional heating, the sleeve W is advanced, and the laser focusing head 20 and the wire supply device 25 are operated to perform the reforming process. It may be.

In this embodiment, the element supply device 25 for supplying the austenite-forming element to the sleeve W includes:
The wire supply device 25 for supplying the reforming wire 26 containing the austenite-forming element to the melted portion of the sleeve W is provided, so that the device for supplying the austenite-forming element becomes extremely simple. However, the present invention is not limited to this, and may be carried out by supplying an austenite-forming element to the melted portion of the sleeve W by an ion implantation device or the like.

Further, in this embodiment, the case where the present invention is applied to the reforming of the sleeve W of the solenoid valve has been described. However, the present invention is not limited to such a cylindrical magnetic circuit member W but may be variously shaped such as a plate. It can also be applied to the magnetic circuit member W of the embodiment. In this case, the irradiation part moving device is, for example, an XY table that grips and moves the magnetic circuit member W in two directions in the vertical and horizontal directions. The reforming may be performed by supplying an austenite-forming element and by preheating with a preheating device. Alternatively, the magnetic circuit member W may be fixedly supported, and the beam irradiation device, the element supply device, and the extra heating device may be attached to a robot arm and moved to perform the reforming.

[0031]

As described above, according to the method for modifying a magnetic circuit member of the present invention, a wide area including the movement trajectory of the irradiated portion of the magnetic circuit member is pre-heated, thereby providing a high energy density beam. As a result, the temperature of the peripheral portion of the portion heated and melted is increased, so that the cooling speed of the melted portion due to heat conduction after passage of the high energy density beam is reduced. Therefore, the heat-affected zone of the base material, which is the boundary with the modified portion, is not quenched, so that a hardened layer is not generated, processing of the magnetic circuit member after the modification becomes easy, and the entire magnetic circuit member is There is no softening and no problems in assembly. In addition, since the formation of a hardened layer is prevented by performing additional heating at the same time as reforming to a weak magnetic material or non-magnetic material, other equipment is unnecessary except for a device for additional heating, and the number of processing steps increases. Nevertheless, when viewed as a whole, the increase in heating energy during processing is very small, so that the increase in manufacturing costs is very small.

In the method of modifying a magnetic circuit member according to the present invention, the temperature of the preheating is lower than the melting temperature of the magnetic circuit member, and the temperature of the heat-affected zone of the magnetic circuit member adjacent to the melted portion is critical cooling. According to the temperature at which the cooling rate becomes equal to or lower than the cooling rate, it is possible to more reliably prevent the quenching of the heat-affected zone and the formation of a hardened layer.

According to the method of modifying a magnetic circuit member of the present invention, the irradiation of the high energy density beam is started immediately after the end of the preheating. Therefore, an apparatus for generating a high energy density beam which is more expensive than other equipment only requires a small capacity, which can reduce equipment cost.

In the method of modifying a magnetic circuit member according to the present invention, if the high energy density beam is a laser beam, the incidental equipment can be simplified and the equipment cost can be reduced.

In the reforming method of the magnetic circuit member according to the present invention, the extra heating is performed by the high-frequency heating coil, so that the deterioration of the material of the magnetic circuit member due to oxidation or the like can be easily prevented.

Further, according to the magnetic circuit member reforming apparatus of the present invention, a wide range including the movement locus of the irradiation site on the magnetic circuit member is reduced to a temperature lower than the melting temperature of the magnetic circuit member by the extra heating device. Since the temperature around the portion heated and melted by the high energy density beam can be kept high by heating, the cooling rate by the heat conduction of the melted portion after passing the high energy density beam is reduced. .
Therefore, as in the case of the method of modifying a magnetic circuit member according to the present invention, the heat-affected zone of the base material, which is the boundary with the modified portion, is not quenched to form a hardened layer. Processing of the circuit member is facilitated, and the entire magnetic circuit member is not softened, so that there is no problem in assembling.
Also, by performing additional heating simultaneously with modification to a weak magnetic material or non-magnetic material, it is possible to prevent the occurrence of a hardened layer,
No additional equipment is required except for the extra heating device, the number of processing steps does not increase, and as a whole, the increase in heating energy during processing is very small. Become.

In the apparatus for modifying a magnetic circuit member according to the present invention, if the extra heating device is a high-frequency heating coil, deterioration of the material of the magnetic circuit member due to oxidation or the like can be easily prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a sleeve which is an example of a magnetic circuit member modified by a method and apparatus for modifying a magnetic circuit member according to the present invention.

FIG. 2 is an overall plan view showing one embodiment of a magnetic circuit member reforming apparatus according to the present invention.

FIG. 3 is an enlarged perspective view of a processing unit of the embodiment shown in FIG.

FIG. 4 is a diagram showing a measurement result of hardness of an example of a sleeve modified according to the present invention, in comparison with a sleeve modified by a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Member supply / extraction device, 15 ... Index table, 16 ... Irradiation site moving device (chuck device), 20 ...
Beam irradiation device (laser focusing head), 25: Element supply device (wire supply device), 26: reforming wire, 30 ...
Extra heating device (high-frequency heating coil), A: detachable part, B: processing part, K: moving trajectory, L: high energy density beam (laser beam), P: irradiated part, W: magnetic circuit member (sleeve), Wa ... Base material, Wb. Reforming part, Wc.

Claims (7)

[Claims] 1. A part of a magnetic circuit member made of an iron-based magnetic material is irradiated with a high energy density beam to melt the irradiated part, move the irradiated part on the magnetic circuit member, and melt the irradiated part. In the method of modifying a magnetic circuit member, in which the vicinity of the movement locus of the irradiation site is modified into a weak magnetic material or a non-magnetic material by supplying an austenite-forming element to the portion where the magnetic circuit member is moved, A method for reforming a magnetic circuit member, characterized by preheating a wide range including a locus. 2. The method for modifying a magnetic circuit member according to claim 1, wherein the temperature of the preheating is lower than a melting temperature of the magnetic circuit member, and the magnetic circuit member is adjacent to the melted portion. Wherein the temperature of the heat-affected zone is a cooling rate at which the cooling rate becomes equal to or lower than the critical cooling rate. 3. The method for modifying a magnetic circuit member according to claim 1, wherein the irradiation of the high energy density beam is started immediately after the end of the preheating. Reforming method. 4. The method for modifying a magnetic circuit member according to claim 1, wherein the high energy density beam is a laser beam. Method. 5. The method for modifying a magnetic circuit member according to claim 1, wherein the extra heating is performed by a high-frequency heating coil. . 6. A magnetic circuit member reformer for modifying a part of a base material made of an iron-based magnetic material into a weak magnetic material or a non-magnetic material, wherein a high energy density beam is applied to a part of the magnetic circuit member. A beam irradiation device that irradiates the irradiated portion by irradiating the magnetic circuit member, an irradiation portion moving device that grips the magnetic circuit member and moves the irradiated portion on the magnetic circuit member, and the melted portion of the magnetic circuit member. An element supply device that supplies an austenite-forming element to a portion that is present, and a preheating device that preheats a wide range including a movement locus of the irradiation site on the magnetic circuit member to a temperature lower than the melting temperature of the magnetic circuit member. A reformer for a magnetic circuit member, comprising: 7. The reformer for a magnetic circuit member according to claim 6, wherein the extra heating device is a high-frequency heating coil.