JP2002012902A - High frequency sintering method for bimetallic bearing alloy, temperature measuring method during high frequency sintering, and sintering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency sintering method for sintering a bearing alloy on a backing metal, greatly reducing the length of a sintering furnace, and maintaining product quality equal to or higher than conventional sintered bearings. I do. SOLUTION: (1) Pre-stage (temperature up to near the Curie point of steel, hereinafter the same) heating by solenoid coil type induction heating 8; Sub-stage (higher temperature than the former stage, same hereafter) heating by transverse coil type induction heating 9; (2) Pre-heating by solenoid coil type induction heating 8, post-heating by combined use of transverse coil 9 and solenoid coil 8, (3) Integrated front and rear heating by transverse coil induction heating 8, (4) Transverse coil 8 And high-frequency sintering method of four types of integrated heating of the former stage and the latter stage using the solenoid coil 9 together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency sintering method for a bimetallic bearing alloy, and more particularly to a method for sintering a bearing alloy bimetal for a sliding bearing, and a sintering apparatus. is there. Furthermore, the invention relates to a method for measuring the temperature of a bearing alloy during sintering.

[0002]

2. Description of the Related Art The most common method of producing a bimetallic sintered bearing alloy comprising at least substantially a steel backing metal and a bearing alloy sintered layer bonded to the backing metal is performed by electrically sintering the entire body. This is a method performed in a resistance heating furnace. In this method, the total length of the sintering line reaches several tens m or more, depending on conditions such as the sintering temperature. By the way, the powder having the composition of the copper alloy sintered layer is laminated on the back metal, and the copper alloy powder and the back metal are subjected to high-frequency induction heating by a solenoid coil and preheated in the reducing atmosphere to near the Curie point of the steel of the back metal, followed by A sintering method in which the temperature is raised to a sintering temperature in a reducing atmosphere of an electric resistance furnace to form a copper alloy sintered layer and this layer is joined to the back metal is known in Japanese Patent Publication No. Hei 7-26125. It is. In this method, it is stated that the entire length of the sintering line is expected to be shortened by rapid temperature rise by high-frequency induction heating, and that production efficiency is expected to be increased. In addition,
This method requires a sintering time of 3 to 12 minutes in an electric furnace. A similar method is also proposed in Japanese Patent Publication No. 1-503150, which states that the lead phase, which is the secondary phase of the copper alloy, is made finer. In a sintering example using a back metal having a thickness of 0.075 inches, the sintering time in the electric furnace is 5.1 minutes. In the past, the temperature of the bearing alloy during sintering was conventionally measured by inserting a thermocouple into a sintering furnace, but an appropriate temperature measurement method during high-frequency sintering has not been studied. is there.

[0003]

In the conventional copper alloy high-frequency sintering method, rapid preheating is performed by high-frequency induction heating up to near the Curie point of steel.
Since sintering of a copper alloy at 73 K (1000 ° C.) is a method other than high-frequency induction heating such as electric resistance heating, the electric resistance heating furnace is used as shown in FIG. However, the furnace length was longer than that of the high-frequency heating furnace, and the sintering line was not sufficiently shortened from the viewpoint of equipment. The sintering of copper alloys for plain bearings is generally performed at 1023K (750 ° C) to 12
The reaction is performed in a temperature range of 23K (950 ° C.) in a reducing atmosphere such as hydrogen or nitrogen. As a result, the copper alloy particles bond with each other and the copper alloy is also bonded to the back metal. It is important for copper alloy sintering to induce a high-frequency current in the back metal and copper alloy powder (hereinafter collectively referred to as “work”) passed in such a sintering atmosphere. In terms of method, the conventional method has insufficient production efficiency. In addition to this, it is desirable to complete the sintering in as short a time as possible to prevent the lead particles of the copper alloy from becoming coarse, and the like, but in this respect, the results of the conventional method have not been sufficient.
The thermocouple normally used for temperature measurement in the sintering method measures the ambient temperature near the work, but the high-frequency heating cannot measure the temperature of the work accurately even if the ambient temperature is measured.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above background, and is broadly classified into (1) a former stage by a solenoid coil type induction heating as a method of high frequency induction heating of a bimetallic slide bearing alloy. Heating to near the Curie point of steel, the same applies hereinafter) Heating, subsequent-stage (higher temperature than the former stage, same hereafter) heating by transverse coil induction heating, (2) Front-stage heating by solenoid coil type induction heating, transverse coil and solenoid There are provided four types of heating: post-coil combined heating, (3) pre- and post-stage integrated heating by transverse coil induction heating, and (4) pre- and post-stage integrated heating using both a transverse coil and a solenoid coil. Further, as an embodiment of the method (2), a method in which heating by the transverse coil is limited to both side edges of the back metal is also provided.

[0005] That is, the high-frequency sintering method for a bimetallic bearing alloy according to the first method is a bimetallic bearing alloy comprising at least a back metal substantially made of steel and a bearing alloy sintered layer joined to the back metal. In the method of manufacturing, the powder having the composition of the bearing alloy sintered layer is laminated on the back metal, the back metal and the bearing alloy powder laminated thereon,
In a reducing or inert atmosphere, the back metal is heated to the vicinity of the Curie point of the steel by solenoid coil type high frequency induction heating, and then heated to the sintering temperature by transverse coil type high frequency induction heating ( Hereinafter, referred to as a "first invention method"), the high-frequency sintering method for a bimetallic bearing alloy according to the second method includes at least a back metal substantially composed of steel and a bearing alloy sintered layer joined to the back metal. When producing a bimetallic bearing alloy consisting of, the powder having the composition of the bearing alloy sintered layer is laminated on the back metal, and the bearing alloy powder and the back metal are reduced in a reducing or inert atmosphere in a solenoid coil type high frequency. The backing metal is heated to the vicinity of the Curie point of the steel by induction heating, and then heated in a reducing or inert atmosphere to a sintering temperature by a solenoid coil type And induction heating, for example characterized by a combination of transverse coil type high frequency induction heating for the back metal side edges (hereinafter referred to as "second invention method"),
The method of high-frequency sintering of a bimetallic bearing alloy according to the third method is to produce a bimetallic bearing alloy including at least a back metal substantially made of steel and a bearing alloy sintered layer bonded to the back metal. The powder having the composition of the bearing alloy sintered layer is laminated on the backing metal, and in a reducing or inert atmosphere, the vicinity of the Curie point of the steel of the backing metal and further up to the sintering temperature are obtained by transverse coil type high frequency induction heating. The method is characterized in that heating is performed (hereinafter, referred to as "third invention method"), and the high-frequency sintering method of the bimetallic bearing alloy according to the fourth method is characterized in that at least substantially a steel back metal is joined to the back metal. When producing a bimetallic bearing alloy comprising a bearing alloy sintered layer, a powder having the composition of the bearing alloy sintered layer is laminated on the back metal, and the bearing alloy powder and The backing metal is heated in a reducing or inert atmosphere to a temperature near the Curie point of the steel of the backing metal and further to a sintering temperature by using both a solenoid coil type high frequency induction heating and a transverse coil type high frequency induction heating. (Hereinafter referred to as “fourth invention method”).
Hereinafter, the present invention will be described in detail.

First, matters common to the first to fourth invention methods will be described. The bearing alloy sintered according to the present invention includes various copper alloys such as bronze, lead bronze, and phosphor bronze, as well as iron, stainless steel, and the like. The copper alloy includes a Cu-Ag-based alloy for a sliding bearing as proposed by the present applicant in JP-A-9-125176. In particular,
The method of the present invention can be preferably applied to a copper alloy containing 7 to 33% by mass of Pb generally used for a sliding bearing. In addition, the copper alloy of the present invention may be made of a hard material such as carbide, nitride, oxide, phosphide, boride, intermetallic compound, or hard alloy to improve abrasion resistance, or graphite to enhance lubricity. , MoS _{2, and the} like may be dispersed. In this case, these powders are also mixed with the copper alloy powder. Hereinafter, the present invention will be described mainly by taking a copper alloy as an example.

Next, in the present invention, the back metal is used as a medium for heat transfer to the copper alloy by high-frequency induction heating in addition to being a support for the sintered alloy. The thickness of this back metal is 0.3-6m
It is preferable to use those having a range of m. Here, if the thickness is less than 0.3 mm, the strength as a structural component is low, while if it exceeds 6 mm, the temperature rise of the back metal by high-frequency induction heating becomes insufficient, and as a result, sintering becomes insufficient. It is preferable to be less than the upper limit. The width of the back metal is determined by the use of the copper alloy. The back metal sheet is usually a cold-rolled steel sheet of low carbon steel, but if necessary, it may be subjected to treatment such as surface roughening treatment, pickling, alkali degreasing, skin pass pressure reduction, Ni plating, and compounding by cladding with different materials. Alternatively, the strength may be increased by adding a trace element. The length of the back metal is not particularly limited, but it is preferable to use a long material generally used in the field of plain bearings and cut it to a required length after sintering.

In the present invention, a work is prepared by forming a layer of a powder having a composition of a copper alloy on a back metal.
As this method, a spraying method in which powder is dropped from a hopper as conventionally performed can be used. The powder having the composition of the copper alloy is a powder in which the powder particles themselves have the composition of the copper alloy, a mixed powder of a Pb-rich powder and a Pb poor powder in a Cu-Pb alloy, and other various powders.

Next, a transverse high-frequency induction heating (tr
ansverse flux heating) will be described. In the solenoid coil type high frequency induction heating employed in the prior art, the axis of the solenoid coil surrounding the plate-like work and the plate surface are parallel. In a reverse coil type high-frequency induction heating different from this, as shown in FIG. 1, the high-frequency induction coil is arranged so as not to surround the plate-shaped work but to face any plate surface. The prior art relating to a transverse high-frequency induction heating coil is disclosed in U.S. Pat. No. 4,751,360.
U.S. Pat. No. 540, which proposes an improvement in this coil shape.
No. 3994, U.S. Pat. No. 5,739,506, which proposes a method for uniformly heating the edge of the plate, and U.S. Pat. No. 2,448,012, which aims to provide uniform heating of the strip by providing a shielding means at the edge of the continuously running strip. It is intended to uniformly heat thick materials such as steel slabs,
No mention is made of heat sintering of bimetallic copper alloys. As described above, conventionally, the transverse coil type high-frequency induction heating method has been mainly used for uniformly heating relatively thick materials such as steel slabs and strips in terms of thickness and width. The present invention has been completed in the high-frequency induction heating by focusing on the fact that the rate of temperature rise above the Curie point does not decrease for thin plates having a thickness of 10 mm or less.

Next, a first invention method in which the back metal is heated to the vicinity of the Curie point of the steel by a solenoid coil type high frequency induction heating, and subsequently heated to a sintering temperature by a transverse type high frequency induction heating will be described. By carrying out high-frequency induction preheating to the vicinity of the Curie point of the steel of the back metal while transporting the work, heat is applied to the copper alloy powder by heat conduction and radiation from the back metal to rapidly raise the temperature to near the sintering temperature. To explain this preheating method sequentially, first, the temperature near the Curie point is the surface temperature of the back metal, which is slightly higher than the average temperature of the copper alloy powder. Next, it is most preferable that the heating temperature substantially coincides with the Curie point, but there is no problem even if the temperature is slightly higher or lower. However, if the temperature of the backing metal exceeds the Curie point, the rate of temperature rise is drastically reduced, so that it rarely exceeds the Curie temperature significantly. Next, the fact that the heating temperature coincides with the Curie point can be detected by a temperature measurement method described later. The high frequency frequency generated by the solenoid coil is 10
４００400 kHz. The number of turns of the high-frequency induction coil is determined in consideration of the moving speed of the work, the thickness of the back metal, and the like. Preheating is preferably performed from room temperature, but if the back metal has been heated to room temperature or higher by the previous process,
Preheating can be performed from that temperature without any problem. Finally, the atmosphere during the heating is 423 K, where oxidation of the copper alloy occurs.
(150 ° C.) or higher, or at a lower temperature, to a reducing or inert atmosphere. The heating time from the room temperature to the Curie point is one time for a typical plain bearing for medium-sized passengers.
Within minutes, most typically about 20 seconds.

Subsequently, the subsequent heating by the transverse coil is typically performed at a temperature of the backing metal of 1023K (750).
C) to 1273 K (1000 C). In this latter-stage heating, the back metal is rapidly and uniformly heated to the sintering temperature, and a temperature distribution in the width direction of the back metal of preferably 20K or less, more preferably 5K or less is achieved. On the other hand, when the post-stage heating by the solenoid coil is performed, even under the optimum condition, the heating rate is 1/5 or less of the method of the present invention,
The temperature distribution is a maximum of 200 K ° C. The frequency of the transverse high-frequency induction heating is preferably 3 to 10 kHz. The heating time from the Curie point to the sintering temperature is within 1 minute for a typical plain bearing for a medium-sized passenger, and is most generally about 40 seconds. The holding time at the sintering temperature after the temperature rise is generally in the range of zero to three minutes. Here, zero holding time means that cooling is started at the moment when the back metal reaches the sintering temperature. In the present invention, the sintering temperature is a temperature within a temperature range suitable for sintering, and holding at the sintering temperature does not mean holding at a constant temperature. Therefore, the sintering temperature range is from 1163K (890 ° C) to 1253K (980).
(° C.), it is possible to adopt a method in which the temperature is continuously increased to 1223 K (950 ° C.), and the temperature is immediately cooled from 1223 K (950 ° C.).

In the present invention, the following phenomena (a), (b) and / or (c) occur. (B) When the method of the present invention is compared with a method in which high-frequency induction heating is performed up to the Curie point and electric resistance heating is performed in a temperature range equal to or higher than the Curie point, the present invention directly heats the back metal to form a sintered alloy layer. Is thermally conducted from the back metal, and sintering proceeds from the contact surface between the back metal and the alloy layer, so that good adhesive strength can be obtained. (B) In a similar comparison, since the unsintered upper portion of the copper alloy powder is kept at a porous state because it is lower in temperature than the lower portion, it can be sufficiently contacted with the reducing gas, and as a result, the sintered structure is improved and The sintering strength also increases. (C) In a similar comparison, the copper alloy structure is fine and uniform because the residence time at the sintering temperature of the work is short.

In the first and second heating steps, it is generally necessary to bring the copper alloy powder into contact with a reducing or inert gas at a temperature higher than the temperature at which oxidation of the copper alloy occurs.
This temperature is generally above 423K (150 ° C).
Any method may be used as a method of bringing the gas into contact with the gas, but it is preferable to use a method of using a non-magnetic, non-conductive protective atmosphere tube such as quartz and disposing a high-frequency induction coil outside the tube.

Further, the back metal is heated to near the Curie point of the steel of the back metal by a solenoid coil type high frequency induction heating,
Next, a second invention method using both the solenoid coil type high frequency induction heating up to the sintering temperature and the transverse coil type high frequency induction heating for both side edges of the back metal will be described. As described in paragraph 0011, there is a problem with the solenoid coil system, but by using it in combination with the transverse coil, the adverse effects can be made less noticeable. In particular, a steep temperature drop at both side edges of the back metal by the solenoid coil system can be compensated by using a transverse coil system that heats both side edges. From the time series point of view, there is a method of simultaneous induction heating using the solenoid coil method and the transverse coil method; (b) sequential heating method using the solenoid coil method and the transverse coil method. As the heating area by the transverse coil method, there are a method of heating (a) the entire sheet width of the back metal, and a method of heating both side edges of the sheet width (b), (b), (b), and (a). And (b) can be appropriately combined. Further, for example, one or more devices (a) + (b) and one or more devices (b) + (b) may be alternately arranged on the same line. In the second invention method, the rate of temperature rise is slightly lower than in the first invention method, but a result comparable in temperature distribution can be realized. The heating time from the Curie point to the sintering temperature is
Typical plain bearings for medium sized passengers use less than 2 minutes, most typically about 60 seconds. The description of the first invention method, which is not inconsistent with the description of this paragraph 0014, is cited in this paragraph and will not be repeated. In particular, the structure and material properties of the sintered alloy described in paragraph 0012 are the same as those of the first invention method.

Next, a description will be given of a third invention method in which high-frequency induction heating is performed consistently by a transverse coil up to the vicinity of the Curie point of the steel of the back metal and further up to the sintering temperature. Below the Curie point of the steel of the backing metal, the temperature rise rate of the transverse coil type high frequency induction heating operated under optimal conditions is lower than that of the solenoid coil type high frequency induction heating also operated under optimal conditions, and the temperature distribution is almost the same. it can.
The description of the first invention, which is not inconsistent with the description of this paragraph 0015, is cited in this paragraph and will not be repeated. In particular, the structure and material properties of the sintered alloy described in paragraph 0012 are the same as those of the first invention.

Finally, a fourth invention in which high-frequency induction heating is performed to near the Curie point of the steel of the back metal and further to the sintering temperature by using both a solenoid coil and a transverse coil will be described. In the present invention, the subsequent heating is performed in the second
The present invention is the same as the invention, and differs from the above-described inventions in that the former stage heating uses a solenoid coil and a transverse coil in combination to perform high-frequency induction heating. The method of combination is the second
Reference is made to the description of the inventive method. In the first stage heating, the rate of temperature rise is lower than that of the first invention and higher than that of the second invention. The description of the first invention and the second invention, which are not inconsistent with the description of this paragraph 0016, are cited in this paragraph and will not be repeated. In particular, paragraph 001
The structure and material properties of the sintered alloy described in 2 are the same as those of the first invention method.

In order to use the work as a sliding bearing, re-sintering is performed after cold compression is performed to densify the sintered layer. The resintering method preferably employs any one of the first to fourth methods of the present invention, usually the same method as the first sintering.

[0018] A sintering apparatus according to the present invention corresponds to the first to fourth invention methods, respectively, and comprises a bimetal including at least a back metal substantially composed of steel and a copper alloy sintered layer joined to the back metal. In a sintering apparatus for producing a copper alloy, means for conveying a back metal, means for spraying a powder having the composition of the copper alloy sintered layer on the back metal, and an inert gas or a reducing gas Means for contacting the back metal, a solenoid coil type high frequency induction heating means for heating to near the Curie point of steel, and a transverse coil type high frequency induction heating means for heating from near the Curie point of the back metal to the sintering temperature (Hereinafter referred to as “first invention device”), a bimetallic copper alloy comprising at least a back metal substantially composed of steel and a copper alloy sintered layer joined to the back metal Manufacture Means for conveying a back metal, means for spraying a powder having the composition of the copper alloy sintered layer on the back metal, and means for bringing the copper alloy powder into contact with an inert gas or a reducing gas. A solenoid coil type high frequency induction heating means for heating to the vicinity of the Curie point of the steel of the back metal, and a high frequency induction heating using a solenoid coil and a transverse coil for heating from the vicinity of the Curie point of the back metal to the sintering temperature (Hereinafter referred to as "second invention device"), a bimetallic copper alloy comprising at least substantially a steel back metal and a copper alloy sintered layer joined to the back metal Means for transporting a long back metal in its length direction, means for spraying a powder having the composition of the copper alloy sintered layer on the back metal, and inactivating the copper alloy powder. Means for bringing the back metal into contact with the steel near the Curie point, a transverse coil type high frequency induction heating means for heating the steel to the vicinity of the Curie point, and a transformer for heating the metal from the vicinity of the Curie point of the steel to the sintering temperature. A sintering device including a berth coil type high frequency induction heating means (hereinafter referred to as "third invention device"), and a back metal substantially made of steel and a copper alloy sintered layer joined to the back metal. A sintering apparatus for producing a bimetallic copper alloy comprising: a means for conveying a back metal; a means for spraying a powder having the composition of the copper alloy sintered layer on the back metal; Or a high-frequency induction heating means using a combination of a solenoid coil and a transverse coil for heating to the vicinity of the Curie point of the steel of the back metal; A sintering apparatus including a solenoid coil for heating from the vicinity of the Lie point to the sintering temperature and high-frequency induction heating means using a transverse coil in combination (hereinafter referred to as a "fourth invention apparatus")
). As a means for bringing the copper alloy powder into contact with an inert gas or a reducing gas, an electrically non-conductive, non-magnetic and airtight protective tube surrounding the back metal at a position intermediate the back metal and the high-frequency induction heating means is used. And a gas source for flowing an inert gas or a reducing gas into the protective tube.

Hereinafter, a sintering apparatus according to the present invention will be described with reference to the drawings. As shown in the conceptual diagram of FIG. 2, the sintering apparatus according to the present invention includes a sintering furnace 5, that is, a high-frequency induction heating furnace and a backing metal 1, such as a hopper 2 for laminating the copper alloy powder 3 on the backing metal 1. It comprises an uncoiler 4a for rewinding the back metal coil for transport in the length direction and a recoiler 4b for winding. The motor for driving the recoiler 4b, the speed reducer, and the like are not shown. When the back metal is transported not in the coil shape but in the shape of a cut plate, a threading roller or a mesh belt is used instead of the (en) coiler. Can be used. Recoiler 4b rotated by driving means (not shown)
Means that the backing metal 1 has a thickness of 1 to 10 m / min.
The sheet is passed through the sintering furnace 5 at a speed of about 6 m / min for mm and 1.5 m / min for a sheet thickness of 6 mm. Of course, this value is a preferable example, and the passing speed may be reduced as the thickness of the back metal plate increases, the high-frequency power decreases, and the high-frequency frequency increases. Further, as shown, immediately after the sintering furnace 5, gas cooling and / or
Alternatively, it is preferable to provide a cooling chamber 6 for performing roll cooling or the like and quickly cool the work to the temperature of the next step. The copper alloy powder inside the sintering furnace is brought into contact with hydrogen gas or the like by sintering atmosphere setting means described later. According to such a present invention, the copper alloy sintering furnace 5 for a sliding bearing is provided.
Is less than half of the conventional length.

In FIG. 3, which conceptually shows a sintering furnace embodying the first apparatus of the present invention, at least one solenoid coil type high frequency induction heating section 8a provided inside a furnace body made of refractory heat insulating material. , 8b, 8c (hereinafter “solenoid coil”)
) Heats the backing metal near the Curie point of the steel.
The solenoid coils 8a, 8b and 8c are known heating means for generating a high-frequency magnetic field in the direction of the back metal plate, and have an arbitrary shape surrounding the work 7. Solenoid coil 8
a, 8b and 8c may be provided in one or more stages as shown and connected to a high-frequency oscillator, or may be provided in only one stage. The distance between the solenoid coils 8a, 8b, 8c and the work 7 is 40 mm or less, particularly 10 to 30 mm or less, and is preferably as small as possible within a range in which a protective tube described later does not come into contact with the coils 8a, 8b, 8c.

Following the solenoid coils 8a, 8b, 8c, a transverse coil type high frequency induction heating section 9a, 9
b, 9c (hereinafter referred to as “transverse coils”). The transverse coils 9a, 9b, 9c are opposed to each other with the work 7 therebetween. Such a transverse coil itself is known in Japanese Patent Publication No. 7-7704, Japanese Patent No. 2875489, U.S. Pat. No. 4,751,360, No. 5,403,994, and No. 5,739,506. The transverse coils 9a, 9b, 9c may be provided in two or more stages as shown in the figure and connected to a high-frequency oscillator, or may be provided in only one stage. The distance between the transverse coils 9a, 9b, 9c and the work 7 is 40
mm or less, particularly 10 to 30 mm or less, and is preferably as small as possible within a range in which a protective tube described later does not come into contact with the coils 9a, 9b, and 9c.

In FIG. 3, the coils 8a, 8
Radiation thermometers 12a, b, c, d, e, and f are arranged in the middle of b, 8c, 9a, 9b, 9c and after the coil 9c,
It is configured to detect that the temperature of the workpiece 7, which is heated very quickly, is within a predetermined target range. That is, for example, if the temperature detected by the radiation thermometer 12b is significantly lower than the Curie temperature, the temperature rise in the transverse coils 9a and 9b may be insufficient. Further, in the rapid temperature rise which is a feature of the present method, the temperature detected by the radiation thermometer 12d may be much higher than the predetermined sintering temperature, or the temperature may not be sufficiently increased when the passing speed is high. It is preferable to perform multi-stage temperature measurement as shown.

The sintering atmosphere can be set by a method in which a high-frequency induction coil is placed in a furnace in which the entire furnace is in a predetermined atmosphere, for example, a mixed atmosphere of hydrogen and nitrogen. On the other hand, there is also an advantage that the current efficiency is high because the distance between the high-frequency induction coil and the work can be reduced. In order to sufficiently exhibit the feature (ii) of paragraph 0012, the present inventors have created a sintering atmosphere limited to a space area extremely close to the work instead of the entire inside of the furnace. Experiments have been carried out under the idea that it is beneficial to arrange them outside the area, and it has been found that, surprisingly, the problems associated with the increase in the spacing between the high-frequency induction coil and the work are practically negligible. Therefore, FIGS.
The method for setting the sintering atmosphere according to the present invention will be described with reference to FIG. 3. An atmosphere having properties such as heat insulation, non-conductivity, non-magnetism, and airtightness such as quartz glass and ceramics is provided inside the solenoid coil 8. A protective tube 22 for sealing is arranged, the work 7 can be transported inside the protective tube 22, and a hydrogen / nitrogen mixed gas, an argon / nitrogen mixed gas, etc.
When flowing from a gas source (not shown) from the outlet side of the furnace via a valve, a flow meter, or the like, the copper alloy powder 3 is subjected to high-frequency induction heating while being in contact with these gases. The inner diameter of the protective tube 22 is determined from both aspects such as heating efficiency depending on the high-frequency current reaching distance and avoiding danger of contact with the workpiece 7 that shows waving behavior during passing.
It is preferably 20 to 50 mm. Although the solenoid coil 8 is shown in FIGS. 4 and 5, a protection tube can be similarly provided in the transverse coil. In the sintering atmosphere setting method as shown in the figure, since the sealing property of the protective tube 22 is superior to that of the conventional method in which the entire inside of the heating furnace is used as the atmosphere gas, there is no mixing of air or the like and the atmosphere is reduced. The good retention of the acidity and the non-oxidizing property is described in paragraph (0012) (b).
It is estimated that this contributes to fully exhibiting the features.

FIG. 6 shows an embodiment embodying the second apparatus of the present invention. In FIG. 6, the solenoid coils 8a, 8b
Heats the back metal to the vicinity of the Curie point, and at a higher temperature, heating is performed by the combined use of the solenoid coils 8c, 8d, 8e, 8f and the side edge heating transverse coils 14a, 14b. Since the temperature of the side edges of the work 7 is more likely to drop than that of the center, the transverse coil 14 for heating the side edges is used.
a and 14b are arranged as shown in FIG.

The inventor tried various methods of measuring temperature,
(A) The radiation from the work physically indicates the apparent temperature, but to correct this to the actual temperature, the emissivity or the emissivity ratio can be used; The measurement has no time lag, and the wavelength of the workpiece passing through the plate can be detected immediately; (iii) The synchrotron radiation sensor is a non-contact method with the workpiece and focuses on the fact that it is not affected by high-frequency induction. A temperature measurement method shown in FIG. That is, in FIG. 7 in which the illustration of the sintering furnace body and the coil is omitted, reference numeral 12 denotes a radiation thermometer, and for example, a radiation thermometer (trade name: IRC) manufactured by CHINO can be used. The radiation thermometer is provided with a total of four radiation thermometers 12a for measuring the front surface of the work 7, 12b and 12d for measuring the edge of the rear surface, and 12c for measuring the center of the rear surface. The work backside measurement radiation thermometers 12b and 12d can directly measure the back metal temperature, and the work surface measurement radiation thermometer 12a can measure the temperature of the powder through the heat-resistant glass 15a. The radiation thermometers 12b, 12c, and 12d receive radiation light from the work 7 via the heat-resistant glass 15d. Note that the temperature measurement method according to the present invention can be applied to a conventional high-frequency sintering method, and the radiation thermometer may be scanned in the width direction of the work instead of the embodiment of FIG.

The embodiments of the first and second invention devices have mainly been described above with reference to the drawings. However, it is easy to modify and combine them to form the third and fourth invention devices. There will be.

[0027]

[Experimental example] The above condition range (however, final heating temperature by solenoid coil = 1013K (740 ° C), final sintering temperature by transverse coil = 1223K (95%)
0 ° C), sintering furnace length = about 3m, back metal plate thickness = 0.7mm,
Sheet passing speed = 6 m / min, the sintering atmosphere -N ₂ -H ₂ mixture gas,
When phosphor bronze was sintered by the first invention method at a sintered layer thickness of 0.3 μm, the entire sintering process was completed in 0.75 minutes. The adhesion strength between the sintered layer and the back metal was good.

[0028]

As described above, the method and apparatus for sintering a bimetallic copper alloy by high-frequency induction heating according to the present invention have excellent industrial advantages. In doing so, it is highly desirable to employ the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a transverse high-frequency induction heating.

FIG. 2 is a conceptual diagram of a sintering apparatus according to the present invention.

FIG. 3 is a conceptual diagram showing a sintering furnace that embodies the first method and the first apparatus of the present invention.

FIG. 4 is a cross-sectional view of a solenoid coil heating section of a sintering furnace for explaining a method for setting a reducing or inert sintering atmosphere in the present invention.

FIG. 5 is a plan view showing an example of an arrangement of coils in a solenoid coil type high frequency induction heating portion of FIG. 2;

FIG. 6 shows an example of an arrangement of high-frequency induction coils embodying the second method and the second device of the present invention.

FIG. 7 is an explanatory diagram illustrating an example of a method of measuring a temperature of a work.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 back metal 2 hopper 3 copper alloy powder 4 a uncoiler 4 b recoiler 5 sintering furnace (high frequency induction heating furnace) 6 cooling chamber 7 work 8 solenoid coil type high frequency induction heating section 9 transverse coil type high frequency induction heating section 10 transverse coil 12 Radiation thermometer 14 Transverse coil type high-frequency induction heating section for peripheral edge heating

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[Procedure amendment]

[Submission Date] June 27, 2000 (2006.2
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F27D 11/06 F27D 11/06 Z (72) Inventor Tsuneya Tsuzuki 3-65 Midorigaoka, Toyota-shi, Aichi Pref. (72) Inventor Hiroaki Kobayashi 3-65, Midorigaoka, Toyota-shi, Aichi Prefecture Inside Daitoyo Kogyo Co., Ltd. (72) Inventor Yasuhisa Nakano 3-65, Midorigaoka, Toyota-shi, Aichi Prefecture Taito Kogyo Co., Ltd. F-term (Reference) 4K018 AA04 BA02 DA26 DA31 JA22 KA03 4K050 AA04 BA02 BA03 CD07 CG01 4K063 AA07 BA02 BA03 BA11 DA05 DA07 FA32 FA43

Claims (19)

[Claims] 1. A method for producing a bimetallic bearing alloy comprising a back metal at least substantially consisting of steel and a bearing alloy sintered layer bonded to the back metal, wherein the composition of the bearing alloy sintered layer is provided. A powder is laminated on the backing metal, and the bearing alloy powder and the backing metal are heated by a solenoid coil type high frequency induction heating until the vicinity of the Curie point of the steel of the backing metal in a reducing or inert atmosphere. Alternatively, a high-frequency sintering method for a bimetallic bearing alloy, wherein heating is performed to a sintering temperature by a transverse coil type high-frequency induction heating in an inert atmosphere. 2. A method for producing a bimetallic bearing alloy comprising at least a back metal substantially made of steel and a bearing alloy sintered layer joined to the back metal, the powder having the composition of the bearing alloy sintered layer. Is laminated on the back metal, and the bearing alloy powder and the back metal are heated to near the Curie point of steel of the back metal by high-frequency induction heating using a solenoid coil in a reducing or inert atmosphere. High-frequency sintering method for bimetallic bearing alloys, characterized by heating to sintering temperature by using both solenoid coil type high frequency induction heating and transverse coil type high frequency induction heating to sintering temperature in neutral or inert atmosphere . 3. The high frequency sintering method for a bimetallic bearing alloy according to claim 2, wherein the transverse coil in the combined heating heats both side edges of the back metal. 4. The high frequency sintering method for a bimetallic bearing alloy according to claim 3, wherein the transverse coils and the solenoid coils in the combined heating are alternately arranged in the length direction of the back metal. 5. A method for producing a bimetallic bearing alloy comprising a back metal at least substantially composed of steel and a sintered bearing alloy layer bonded to the back metal, the powder having the composition of the sintered bearing alloy layer. Are laminated on the back metal, and the bearing alloy powder and the back metal are heated in a reducing or inert atmosphere up to near the Curie point of the steel of the back metal by a transverse coil type high frequency induction heating, and then reduced. A high-frequency sintering method for a bimetallic bearing alloy, comprising heating to a sintering temperature in a neutral or inert atmosphere by a transverse coil type high-frequency induction heating. 6. A powder having the composition of the bearing alloy sintered layer when producing a bimetallic bearing alloy comprising at least substantially a steel back metal and a bearing alloy sintered layer joined to the back metal. Is laminated on the back metal, the bearing alloy powder and the back metal are subjected to a solenoid coil type high frequency induction heating and a transverse coil type high frequency induction heating up to near the Curie point of steel of the back metal in a reducing or inert atmosphere. Bimetallic bearing characterized in that heating is performed in combination, and then heating is performed in combination with a solenoid coil type high frequency induction heating and a transverse coil type high frequency induction heating to a sintering temperature in a reducing or inert atmosphere. High frequency sintering method for alloys. 7. The frequency of said solenoid coil type high frequency induction heating is 10 to 400 kHz.
7. The high-frequency sintering method for a bimetallic bearing alloy according to claim 3, 4, or 6. 8. The high-frequency sintering method for a bimetallic bearing alloy according to claim 1, wherein a frequency of the transverse coil type high-frequency induction heating is 1 to 10 kHz. 9. The heating time is 0.5 to 5 minutes.
9. The high frequency sintering method for a bimetallic bearing alloy according to any one of items 1 to 8. 10. A high frequency induction current is generated outside said reducing or inert atmosphere.
10. The high frequency sintering method for a bimetallic bearing alloy according to any one of items 1 to 9. 11. A method for measuring the temperature during high-frequency sintering of a bimetallic bearing alloy comprising a back metal steel sheet and a sintered layer of a bearing alloy, wherein the radiation emitted from the bimetal is received by a radiation thermometer to measure the temperature. A method for measuring the temperature of a bimetallic bearing alloy during high-frequency sintering. 12. A method for measuring the temperature of a bimetallic bearing alloy, wherein the high-frequency sintering is performed by the method according to claim 1. Description: 13. A sintering apparatus for producing a bimetallic bearing alloy comprising at least substantially a back metal substantially made of steel and a bearing alloy sintered layer bonded to the back metal, means for transporting the back metal, Means for laminating a powder having the composition of the bearing alloy sintered layer on the back metal, means for bringing the bearing alloy powder into contact with an inert gas or a reducing gas, and a solenoid coil for heating the back metal to near the Curie point of steel. A sintering apparatus comprising: a high-frequency induction heating means; and a transverse coil high-frequency induction heating means for heating from the vicinity of the Curie point of the back metal to the sintering temperature. 14. A sintering apparatus for producing a bimetallic bearing alloy comprising a back metal at least substantially composed of steel and a bearing alloy sintered layer joined to the back metal, means for conveying the back metal, Means for laminating a powder having the composition of the bearing alloy sintered layer on the backing metal, means for bringing the bearing alloy powder into contact with an inert gas or reducing gas, and a solenoid for heating the backing metal to near the Curie point of steel A sintering apparatus comprising: a coil-type high-frequency induction heating means; and a high-frequency induction heating means using both a solenoid coil and a transverse coil for heating from the vicinity of the Curie point of the steel of the back metal to a sintering temperature. 15. The sintering apparatus according to claim 14, wherein the transverse coils are arranged on both side edges of a back metal. 16. The sintering apparatus according to claim 14, wherein the transverse coil and the solenoid coil in the combined heating are alternately arranged in a direction in which the back metal is transported. 17. A sintering apparatus for producing a bimetallic bearing alloy comprising at least substantially a back metal substantially made of steel and a bearing alloy sintered layer joined to the back metal, means for transporting the back metal, Means for laminating a powder having the composition of the bearing alloy sintered layer on the backing metal, means for bringing the bearing alloy powder into contact with an inert gas or a reducing gas, and a transformer for heating the backing metal to near the Curie point of steel. A sintering apparatus comprising a verse coil type high frequency induction heating means and a transverse coil type high frequency induction heating means for heating the back metal from near the Curie point of the steel to a sintering temperature. 18. A sintering apparatus for producing a bimetallic bearing alloy comprising at least substantially a back metal substantially made of steel and a bearing alloy sintered layer joined to the back metal, means for transporting the back metal, Means for laminating a powder having the composition of the bearing alloy sintered layer on the backing metal, means for bringing the bearing alloy powder into contact with an inert gas or reducing gas, and a solenoid for heating the backing metal to near the Curie point of steel Sintering comprising high-frequency induction heating means using both a coil and a transverse coil, and high-frequency induction heating means using a solenoid coil and a transverse coil for heating from near the Curie point of the steel of the back metal to a sintering temperature. apparatus. 19. The bearing alloy, wherein the means for bringing the bearing alloy powder into contact with an inert gas or a reducing gas comprises an electrically non-conductive, non-magnetic material surrounding the back metal at a position intermediate the back metal and the high-frequency induction heating means. And a protective tube having airtightness,
19. The sintering apparatus according to claim 13, further comprising a gas source for flowing an inert gas or a reducing gas into the protective tube.