JPH1190621A - Method and device for connecting metal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prevent the generation of partial fusions on the top side of a section supporting a metal member at a low cost even if deflection is produced on the supporting section by pressurizing, by means of forming a non-conducting part at the top of an electrode supporting section of a device with which metal members are jointed each other by pressurizing and heat- generating with energizing the metal members. SOLUTION: While a valve seat is placed on a jointing surface of a cylinder head main body 2 on the upper face of a lower electrode 25 of a connecting device 20, the lower face of an upper electrode 24 is brought into contact with the upper face part of the valve seat and the both electrodes are energized while the both members are pressed. A notch 28 is formed as non-conducting part on the lower part which is a contact part with the upper face part of the valve seat of the upper electrode 24. An insulating member can be stuck on the lower face part of the upper electrode 24 instead of the notch 28. In this way, the device is easily provided at low cost without having the connecting device 20 complicated or oversized even if a large deflection is produced by a high pressurizing force in an upper and a lower horizontal parts 21a and 21b of a supporting main body 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a first metal member and a second metal member by heating and pressurization caused by energization between the two metal members. The present invention relates to a joining apparatus, which belongs to the technical field of using two electrodes provided on a pair of supporting portions which are supported in a cantilever manner on a base end side and opposed to each other.

[0002]

2. Description of the Related Art Conventionally, there have been various methods for joining metal members to each other, for example, in a case where a valve seat is joined to a peripheral portion of an opening of an intake and exhaust port of a cylinder head body in an engine cylinder head. It has been known.

[0003] For example, Japanese Patent Application Laid-Open No. H8-100
No. 701, the valve seat and A
It has been proposed that an l-type cylinder head body is brazed and joined with an Al-Zn-based brazing material and a fluoride-based flux.

Further, as disclosed in Japanese Patent Application Laid-Open No. 58-13481, for example, a method is known in which metal members are joined to each other by resistance welding utilizing contact resistance heating at a joint surface of both members. In this resistance welding, as shown in, for example, Japanese Patent Application Laid-Open No. 6-58116, a metal is infiltrated into holes of a valve seat formed of a sintered material, thereby generating heat inside the sintered material. Reducing the amount of heat to increase the amount of heat generated at the joint surface,
For example, as disclosed in Japanese Patent Application Laid-Open No. Hei 8-270499, it has been proposed to form a film on the surface of a valve seat and to melt the film at the time of coupling with a cylinder head body.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. H8-200148, a molten reaction layer is formed while forming a plastically deformable layer on the joint surface of the cylinder head body with the valve seat and the cylinder head body. It has been proposed that solid-phase diffusion bonding (pressure welding) be performed without the need.

[0006]

In the meantime, when metal members are joined to each other by heating and pressurization due to energization between the two members, as in the joining method by resistance welding and the solid-phase diffusion joining method, usually, A joining device similar to a commercially available spot welding machine or the like or a modified joining device is used. This joining device generally has a substantially U-shaped support body with one side opened when viewed from the side, and two electrodes provided on both opposing sides (a pair of support parts) of the support body. And Then, the respective electrodes are placed between the two supporting portions in the first direction.
The metal member and the second metal member are respectively brought into contact with the opposite sides of the respective joint surfaces so as to conduct electricity and pressurize.

However, when the two metal members are joined by energizing and pressurizing using the above-described joining device, the supporting portion is cantilevered with only the base end supported, so Due to the bending, the pressing force is reduced on the opening side of the support body (the tip side of the support portion), and the contact resistance of the portion corresponding to the support portion tip side in the joint surface of the two members is increased accordingly. For this reason, the front end side of the support portion of both members or one of the members may locally melt and a gap may be formed between the two members, and the bonding strength may not be stable. In particular, in the case where the contact resistance is reduced to suppress the heat generation, the bending of the support portion is increased by the high pressure, and the local melting becomes remarkable.

On the other hand, it is conceivable to reduce the amount of bending by connecting the front end portions of the two support portions to each other, but there is a problem that the joining device becomes large and complicated and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a pair of support members which are supported in a cantilever manner at the base end side and opposed to each other, as in the above-described bonding apparatus. In the case where the first metal member and the second metal member are joined between the parts by heat generation and pressurization caused by energization between the two metal members using the two electrodes provided on the both support portions, By improving the electrode of the joining device, even if the supporting portion is bent by pressurization, low-cost and easy local melting of the first metal member or the second metal member on the tip side of the supporting portion. To prevent the occurrence of

[0010]

In order to achieve the above-mentioned object, according to the present invention, a non-conducting portion is formed at the tip of the supporting portion in the electrode.

Specifically, according to the first aspect of the present invention, the first metal member and the second metal member are provided between a pair of support portions which are supported in a cantilever manner on the base end side and face each other. The present invention is directed to a joining method in which two metal members provided on the both support portions are joined by heat and pressure generated by energization between the two metal members.

In the at least one electrode, a non-conducting portion is formed on the tip side of the supporting portion to conduct electricity.

Accordingly, even if the support portion is bent and the contact resistance at the distal end side is high, the non-conductive portion is formed at the distal end side of the support portion of the electrode. The value of the current flowing through the portion corresponding to the front end side of the supporting portion of the metal member becomes small, and the resistance heat generation amount at that portion does not become excessive. On the other hand, since only the non-conductive portion is provided on the electrode, there is no increase in the size of the joining device or increase in cost. Therefore, it is possible to easily and locally prevent the distal end side of the support portion of the first metal member or the second metal member from being locally melted, and to stabilize the bonding strength.

According to a second aspect of the present invention, in the first aspect, the non-conductive portion of the electrode is formed by cutting out a contact portion of the electrode with the first metal member or the second metal member. To do.

According to the present invention, a non-conducting portion can be easily formed in the electrode only by cutting out the electrode. Therefore,
A specific configuration of a simple non-conductive portion can be easily obtained.

According to a third aspect of the present invention, in the first aspect of the present invention, a non-conductive portion of the electrode is attached to an insulating member at a contact portion of the electrode with the first metal member or the second metal member. To form.

Thus, a non-conducting portion can be easily formed on the electrode only by attaching the insulating member. Therefore, the same function and effect as the second aspect of the invention can be obtained.

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the bonding surface of the first metal member has a lower melting point than the first metal member and the second metal member. The brazing material layer is formed via a diffusion layer between the brazing material and the first metal member, and the first metal member and the second metal member are connected to each other by energization between the two metal members. By generating heat and pressurizing to a temperature not lower than the melting point of the brazing material and forming a diffusion layer of the brazing material and the second metal member and discharging the molten brazing material from between the joining surfaces of the two metal members, Bonding is performed in a liquid phase diffusion state via the diffusion layer.

With this, the first metal member and the second metal member are liquid-phase diffusion-bonded in a state where the brazing material is discharged and the two diffusion layers are interposed therebetween, so that the surface of the second metal member is oxidized. The coating and dirt are discharged together with the brazing material, and the two diffusion layers are directly joined without interposing the brazing material layer. Also, although the melting point of the brazing material is usually low, even if the brazing material is discharged and a little remains, the melting point of the brazing material after joining is changed because the ratio of the components of the brazing material changes due to the formation of the diffusion layer. Can be higher. Therefore, the joining strength can be increased as compared with the solid phase diffusion joining, and the heat resistance can be improved more than the brazing material used. In the liquid-phase diffusion bonding method having such an unprecedented advantage, in order to further increase the bonding strength, it is necessary to destroy the oxide film or to effectively discharge the brazing material. Since it is necessary to increase the pressing force, the first
Local melting of the metal member or the second metal member on the distal end side of the support portion cannot be avoided. However, according to the present invention, even if the amount of bending of the supporting portion is increased by the high pressure, the amount of resistance heat generated at the front end side of the supporting portion of both metal members is not excessively increased, and local melting of the portion is prevented. can do. Therefore, while improving the joining strength of both metal members,
The occurrence of defects at the time of joining the two metal members can be prevented, and the joining strength can be stabilized.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the first metal member is made of an Fe-based material, the second metal member is made of an Al-based material, and the brazing material is a Zn-based material. Shall consist of

According to the present invention, since the melting point of the Zn-based brazing material is relatively low, the melting and discharging of the brazing material can be performed easily and reliably. In addition, the Zn-based brazing material easily forms the Fe-based first metal member and the Fe-Zn diffusion layer, and the Al-based second metal member and the Al-Zn diffusion layer, respectively. Further, since the bonding is performed via both diffusion layers, the generation of a brittle intermetallic compound of Fe-Al can be effectively prevented. Therefore, an optimum combination of materials for the joining method according to the fourth aspect of the invention can be obtained.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, the first metal member in the brazing material bath is coated with the brazing material by applying ultrasonic vibration to the first metal member. A brazing material layer and a diffusion layer are formed on a metal member.

As a result, the oxide film and the plating layer on the surface of the first metal member are destroyed by the cavitation effect of the ultrasonic wave, so that the brazing material is rubbed against the surface of the first metal member. The brazing material can be more reliably diffused to the first metal member side than the method using the appropriate friction. Further, a post-process for removing the flux as in the case of performing brazing using the flux is unnecessary.
Therefore, the diffusion layer between the brazing material and the first metal member can be reliably formed by a simple method, and the joining strength between the two metal members can be further improved.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the first metal member is provided inside the first metal member.
Before joining the metal member and the second metal member, the high electrical conductivity material is infiltrated in advance.

By doing so, even if there are pores inside such as a sintered material, for example, the pores are filled with the high electrical conductivity material, and a part of the pressing force crushes the pores. In this case, all of the pressing force is directly applied to the joint surface of the two metal members. In addition, by the infiltration of the high electrical conductivity material, heat generation inside the first metal member can be suppressed at the time of energization, and heat can be generated effectively at the joint surface. In particular, in the invention of claim 4, 5 or 6, the melting and discharge of the brazing material can be effectively performed. Therefore, the joining strength of both metal members can be effectively improved.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the present invention, the first metal member and the second metal member are joined by plastically flowing the joint surface of the second metal member. To do.

As a result, the oxide film on the surface of the second metal member is effectively destroyed, so that it is not necessary to particularly protect the surface of the second metal member. On the other hand, plastic flow of the second metal member can be easily performed by utilizing the pressing force when pressing the first metal member and the second metal member, and no special means is required. . In particular, in the invention of claim 4, 5 or 6, the oxide film and the dirt on the surface of the second metal member are discharged together with the brazing material, so that the brazing material can be surely diffused to the second metal member side, The diffusion layer between the brazing material and the second metal member can be reliably formed by a simple method. Therefore, the joint strength between the two metal members can be further improved.

According to a ninth aspect of the present invention, there are provided a pair of support portions which are supported in a cantilever manner on the base end side and are opposed to each other, and two electrodes provided respectively on the both support portions. The present invention is an invention of a joining apparatus in which a first metal member is joined to a second metal member by heat and pressure generated by energization between the two metal members using both electrodes.

In the present invention, it is assumed that a non-conducting portion is formed at the tip of the support portion in at least one of the electrodes. Thus, the same function and effect as the first aspect of the invention can be obtained.

According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the non-conducting portion of the electrode comprises a cutout portion at a contact portion of the electrode with the first metal member or the second metal member. I do. Thus, the same function and effect as the second aspect of the invention can be obtained.

According to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the non-conductive portion of the electrode is an insulating member attached to a contact portion of the electrode with the first metal member or the second metal member. Shall consist of By doing so, the same operation and effect as the third aspect of the invention can be obtained.

According to a twelfth aspect of the present invention, in any one of the ninth to eleventh aspects, the first metal member and the second metal member are joined by plastically flowing the joint surface of the second metal member. It is assumed to be configured as follows. Thus, the same function and effect as the eighth aspect of the invention can be obtained.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a main part of an engine cylinder head 1 as a joining metal member manufactured by a joining device 20 (see FIG. 7) according to Embodiment 1 of the present invention. , Four intake and exhaust ports 2 in the cylinder head body 2 as the second metal member
The substantially ring-shaped valve seats 3, 3,... (first metal members) are joined to the peripheral edges of the openings b, 2b,. The peripheral edges of the openings of the ports 2b are arranged in a substantially square shape when viewed from the lower side of the cylinder head 1, and the peripheral edges of the openings are the joint surfaces 2a with the valve seats 3.

The inner peripheral surface of each of the valve seats 3 is formed as a valve abutting surface 3c, and is formed in a tapered shape whose diameter decreases upward along the shape of the upper surface of the valve. The outer peripheral surface portion of each valve seat 3 is a first joint surface portion 3a with the cylinder head main body 2, is surrounded by the joint surface portion 2a of the cylinder head main body 2, and is formed in a tapered shape like the inner peripheral surface. ing. Further, the upper surface of each valve seat 3 is in the second position with the cylinder head body 2.
The joining surface portion 3b is inclined upward toward the inner peripheral side.

Each of the valve seats 3 is a sintered material made of an Fe-based material, and a Cu-based material as a high electrical conductivity material is infiltrated therein. This valve seat 3
First and second joint surfaces 3 with the cylinder head body 2
a, 3b, as schematically shown in FIG.
System material (about 95% by weight of Zn component and about 5% by weight of Al
A diffusion bonding layer 5 (diffusion layer) between the brazing material made of the above component and the valve seat 3 is formed. That is, the diffusion bonding layer 5 is made of Fe—Zn formed by diffusing the Zn component of the brazing material to the valve seat 3 side.

On the other hand, the cylinder head main body 2 is made of an Al-based material, and a fusion reaction layer 6 (between the brazing material and the cylinder head main body 2) is formed on a joint surface 2a of the cylinder head main body 2 with each valve seat 3. Diffusion layer) is formed. That is, the molten reaction layer 6 is made of Zn of the brazing material.
It is made of Al-Zn formed by liquid phase diffusion of components in the molten state to the cylinder head main body 2 side.
The melting point of the brazing material is lower than that of each valve seat 3 and cylinder head body 2.

The valve seat 3 and the cylinder head main body 2 are connected to the diffusion bonding layer 5 and the molten reaction layer 6.
The diffusion bonding layer 5 and the molten reaction layer 6 have a total thickness of 1.0 μm or less. In FIG. 2, a brazing material layer 7 is formed between the diffusion bonding layer 5 and the molten reaction layer 6.
Is extremely small and can be considered to be practically negligible.

A method of manufacturing the cylinder head 1 by joining the valve seats 3 to the peripheral portions (joining surfaces 2a) of the ports 2b of the cylinder head body 2 in the cylinder head 1 having the above-described structure will be described. In the following manufacturing process, the top and bottom of the cylinder head body 2 and the valve seat 3 are reversed.

First, the valve seat 3 is manufactured by sintering Fe-based material powder. At this time, as shown in FIG. 3, the valve seat 3 is designed to withstand the pressing force at the time of joining the valve seat 3 and the cylinder head main body 2.
The inner peripheral side and the upper side (the lower side in FIG. 1) are formed so as to be thicker. That is, at this stage, the valve contact surface portion 3c is not formed, and the inner peripheral surface is formed to extend straight upward and the upper surface is formed to be substantially horizontal. Further, the taper angle (θ1 in FIG. 3) of the first joint surface 3a with the cylinder head body 2 is about 0.52 rad.
(30 °), and the inclination angle (θ2 in FIG. 3) of the second joint surface 3b is formed at about 0.26 rad (15 °). That is, the taper angle θ1 of the first joint surface 3a
Is too small, it is easy to embed the valve seat 3 in the cylinder head body 2, but the oxide film destruction effect on the joint surface 2a of the cylinder head body 2 is reduced. Since the embedding becomes difficult and the outermost diameter of the valve seat 3 becomes too large to make it possible to narrow the interval between the two ports 2b, 2b, it is set to about 0.52 rad (30 °).

A ring having substantially the same diameter as the valve seat 3 is manufactured by sintering a powder of a Cu-based material, and the ring is placed on the upper surface of the sintered valve seat 3 to form a heating furnace. Then, the Cu-based material is infiltrated into the interior of the valve seat 3 by being melted. Thereafter, the first and second joint surfaces 3a,
A Cu plating layer (about 2 μm) is applied to the entire surface including 3b from the viewpoint of preventing formation of an oxide film.

Subsequently, as schematically shown in FIG. 5A, the first and second joint surfaces 3a, 3b of the valve seat 3 are formed.
A brazing material layer 7 is formed on 3b via a diffusion bonding layer 5. In order to form the brazing material layer 7 and the diffusion bonding layer 5 on the valve seat 3, the surface of the valve seat 3 in the brazing material bath is coated with a brazing material by applying ultrasonic vibration (ultrasonic plating). That is, as shown in FIG. 6, one end of the diaphragm 11 is attached to the ultrasonic oscillator 12, and the valve seat 3 is placed on the upper surface of the other end of the diaphragm 11 in the bottomed container 13. In a brazing material bath 14. In this state, when ultrasonic vibration is applied to the valve seat 3 from the ultrasonic oscillator 12 via the diaphragm 11, a Cu plating layer on the surface of the valve seat 3 and a slight amount are formed by cavitation by the ultrasonic waves. The oxide film is destroyed, and the Zn component of the brazing material diffuses to the valve seat 3 side to reduce the Fe-Z
A diffusion bonding layer 5 made of n is formed, and a brazing material layer 7 is formed on the surface side of the diffusion bonding layer 5. This makes it possible to form the diffusion bonding layer 5 more reliably and easily than a method using mechanical friction in which a brazing material is rubbed against the surface of the valve seat 3. The conditions for the ultrasonic plating include, for example, a brazing material bath temperature of 400.
° C, ultrasonic output 400 W, ultrasonic vibration application time 20
Seconds can be set for each.

Next, the valve seat 3 is connected to the port 2 of the cylinder head body 2 which has been manufactured in advance by casting or the like.
b, which is joined to the periphery of the opening, that is, to the joint surface 2a with the valve seat 3. At this time, the joining surface portion 2a of the cylinder head main body 2 is different from the shape at the time of joining completion (the same shape as the first and second joining surface portions 3a and 3b of the valve seat 3) as shown in FIG. , About 0.79 rad (45 °).

In order to join the valve seat 3 to the joining surface 2a of the cylinder head main body 2, as shown in FIG. 7, a joining device 20 which is an improved version of a commercially available projection welding machine is used. The joining device 20 has a substantially U-shaped support body 21 having one side opened when viewed from the side, and the upper and lower horizontal portions 2 of the support body 21 facing each other.
1a and 21b (a pair of support portions) are vertical portions 21c on the base end side.
It is a cantilever supported only by. A pressurizing cylinder 22 is provided below the upper horizontal portion 21a of the support main body 21, and is attached to a cylinder rod 23 of the pressurizing cylinder 22 below the pressurizing cylinder 22 and is the same as the cylinder rod 23. A substantially cylindrical upper electrode 24 made of Cu that can move up and down on the axis is provided. On the other hand, on the upper side of the lower horizontal portion 21b, Cu
The lower electrode 25 is provided so as to face the upper electrode 24, and the cylinder head main body 2 is placed on the obliquely upper surface of the lower electrode 25 so that the joint surface 2 a is located above the cylinder head main body 2. It is possible to put on.
The horizontal position of the movable base 27 with respect to the lower horizontal portion 21b and the inclination of the upper surface of the lower electrode 25 can be adjusted, and the center axis of the joint surface 2a for joining the valve seat 3 is vertical and The adjustment is made so as to substantially coincide with the central axis of the electrode 24.

The upper and lower electrodes 24 and 25 are respectively connected to a welding power source 26 housed in the vertical portion 21c of the support main body 21, and a valve is provided on the joint surface 2a of the cylinder head main body 2 on the upper surface of the lower electrode 25. When the lower surface of the upper electrode 24 is brought into contact with the upper surface of the valve seat 3 with the seat 3 placed thereon, the welding power source 26 is turned on while the valve seat 3 and the cylinder head body 2 are pressed by the pressing cylinder 22. The current flows from the valve seat 3 to the cylinder head main body 2. 8A and 8B, the upper electrode 24 has a contact portion with the upper surface of the valve seat 3 on the lower end portion thereof, as shown in an enlarged manner in FIGS. (Support body 2
A cutout 28 as a non-conducting portion is formed on the side of the opening 1.

The cylinder head main body 2 is placed on the upper surface of the lower electrode 25 of the joining device 20, and the movable base 26 is moved in the horizontal direction so that the central axis of the joining surface 2 a joining the valve seat 3 substantially coincides with the upper electrode 24. After adjusting the position and the inclination of the upper surface of the lower electrode 24, the valve seat 3 is placed on the joint surface 2a. At this time, as shown in FIG. 4A, only the corners of the first and second joint surfaces 3a and 3b of the valve seat 3 are in contact with the joint surface 2a of the cylinder head body 2.

Then, the upper electrode 24 is moved downward by the operation of the pressurizing cylinder 22 to come into contact with the upper surface of the valve seat 3, and pressurization of the valve seat 3 and the cylinder head body 2 is started from this state. . This pressure is 294
About 20N (3000 kgf) is desirable. Then, as shown in FIG. 9, while maintaining this pressing force, the welding power source 26 is turned on about 1.5 seconds after the start of pressurization, and the resistance heat generated by energization between the valve seat 3 and the cylinder head body 2 is generated. As a result, heating is performed to a temperature equal to or higher than the melting point of the brazing material in the brazing material layer 7, and the brazing material is melted. This current value is desirably about 70 kA.

At this time, the melting point of the brazing material composed of about 95% by weight of the Zn component and about 5% by weight of the Al component is extremely low at about 380 ° C., as shown in FIG. Further, the joint surface 2a of the cylinder head main body 2 is softened by the resistance heating, and as shown in FIG. 4B, the corner between the first joint surface 3a and the second joint surface 3b of the valve seat 3 is pressurized. The valve seat 3 is buried in the cylinder head body 2 while causing the joint surface 2a of the cylinder head body 2 to plastically flow. As a result, the oxide film on the joint surface portion 2a of the cylinder head body 2 is surely destroyed, and the Zn component of the molten brazing material diffuses in the liquid phase toward the cylinder head body 2 to form the molten reaction layer 6 made of Al-Zn. (See FIG. 5B).

On the other hand, as shown in FIG. 5 (c), almost all the brazing material of the brazing
And, it is discharged together with the oxide film and the dirt from between the second joint surfaces 3a and 3b and the joint surface 2a of the cylinder head body 2. For this reason, the diffusion bonding layer 5 does not pass through the brazing material layer 7.
And the molten reaction layer 6 are directly joined to each other,
Diffusion between them is further promoted. In addition, the formation of a brittle intermetallic compound of Fe—Al can be effectively prevented through the two layers 5 and 6. Therefore, the valve seat 3 and the cylinder head body 2 are joined in a liquid phase diffusion state via the diffusion joining layer 5 and the molten reaction layer 6,
Its bonding strength is very high. Even if a small amount of the brazing material layer 7 remains, the Zn ratio of the brazing material decreases due to diffusion, and its melting point rises to about 500 ° C. or higher (see FIG. 11). For this reason, after joining, it has heat resistance higher than the melting point of the brazing material used.

Further, since the inside of the valve seat 3 is infiltrated with a Cu-based material having a high electric conductivity, the pores formed by sintering are filled with the Cu-based material, and a part of the pressure is applied. Is not used to crush the above-mentioned hole, and all of the pressing force is used to directly plastically flow the joint surface portion 2a of the cylinder head body 2 and to discharge the brazing material. The heat generation inside the valve seat 3 can be suppressed, and the brazing material can be effectively melted.

The upper and lower horizontal portions 21a,
The upper and lower horizontal portions 21a, 2b are cantilevered portions.
Due to the flexure of 1b, the pressing force is reduced on the opening side of the support main body 21, and the contact resistance of the joint surfaces 2a, 3a, 3b corresponding to the opening side of the support main body 21 is increased by that amount, so that the heat generation on the opening side is generated. If the amount becomes excessive, the cylinder head main body 2 may locally melt and a gap with the valve seat 3 may occur. In order to prevent this, as described above, the notch 28 is formed on the lower surface of the upper electrode 24 on the opening side of the support main body 21. In this case, the current value is small in portions corresponding to the valve seat 3 and the opening side of the support main body 21 of the cylinder head main body 2. For this reason, the opening side of the support main body 21 in the cylinder head main body 2 is not locally melted and a gap is formed between the support head 21 and the valve seat 3. Further, since the central axes of the cylinder rod 23 of the pressurizing cylinder 22 and the upper electrode 24 coincide with each other, the difference in the pressing force of the entire upper electrode 24 and the horizontal axis of the upper electrode The change in the directional position can be reduced, the degree of notch of the notch 28 can be reduced, and the misalignment of the valve seat 3 with respect to the joint surface 2a of the cylinder head main body 2 can be prevented. It should be noted that local melting of the cylinder head main body 2 can also be prevented by attaching an insulating member to the lower surface of the upper electrode 24 instead of providing the cutout 28.

Subsequently, when 1.5 to 2.5 seconds have elapsed from the start of energization, the welding power source 26 is turned off to stop energization.
The valve seat 3 is a joint surface 2a of the cylinder head body 2.
(See FIG. 4 (c)).
At this time, the pressurization is continued without stopping. That is, the pressing force is maintained until the molten reaction layer 6 is completely solidified and cooled, and the respective joint surfaces 2 a, 3 a,.
3b prevents peeling and cracking.

As shown in FIG. 10, it is more desirable to reduce the pressing force almost simultaneously with stopping the energization. That is, since there is a high possibility that cracks will occur in the joint surfaces 2a, 3a and 3b due to the pressure immediately after solidification where the deformability becomes small with a large pressing force, the pressing force is reduced to a level that can follow the shrinkage deformation, Cracks at the joint surfaces 2a, 3a, 3b after solidification by pressure are reliably prevented.

Thereafter, the pressure is stopped about 1.5 seconds after the stop of the energization, and the joining of the valve seat 3 and the cylinder head body 2 is completed. Subsequently, the same operation is repeated in the same cylinder head main body 2 so that the remaining 3
The valve seats 3 are joined to the two joining surfaces 2a, 2a,.

Finally, the inner peripheral surface and the upper surface of each valve seat 3 are cut to form a valve abutting surface 3c and finished in a predetermined shape. Thus, the cylinder head 1 in which the valve seats 3 are joined to the peripheral portions of the openings of the ports 2b of the cylinder head body 2 is completed.

Therefore, in the first embodiment, the valve seat 3 and the cylinder head body 2 are joined in a liquid-phase diffusion state via the diffusion joining layer 5 and the molten reaction layer 6 by the heat and pressure generated by energization. As a result, the cylinder head 1 having high bonding strength and heat resistance higher than that of the brazing filler metal used can be obtained in a short time. Further, since it is only necessary to set the pressing force and the current value so that the brazing material can be melted and discharged, the condition range in which high joining strength can be obtained is wide. In addition, the valve seat 3 can be made much smaller than the joining method by shrink fit,
The distance between the two ports 2b, 2b can be reduced or the throat diameter can be increased. Further, the thermal conductivity in the vicinity of the valve can be improved without forming a heat insulating layer, and the cooling water passage provided between the ports 2b, 2b can be made closer to the valve seat side. The temperature in the vicinity can be effectively reduced. In addition, connect a glow plug or injector to port 2
Even if it is arranged between b and 2b, the wall thickness between them can be sufficiently ensured. Therefore, the performance, reliability and design freedom of the engine can be improved.

A notch 28 is formed on the upper electrode 24 on the opening side of the support body 21 (or an insulating member is attached).
Thus, even if the amount of bending of the upper and lower horizontal portions 21a and 21b of the support body 21 is large due to the high pressing force, the joining device 2
0 can be easily prevented at low cost and locally on the opening side of the support main body 21 in the cylinder head main body 2 without increasing the size of the cylinder 0. Therefore, it is possible to prevent the occurrence of defects at the time of joining the respective valve seats 3 and the cylinder head main body 2, and to stably improve the joining strength.

In the first embodiment, the valve seats 3 are manufactured by sintering and the Cu-based material is infiltrated therein. However, the density inside each valve seat 3 is ensured to some extent. If so, it is not necessary to infiltrate. In addition, by forming each valve seat 3 as a sintered forged material obtained by forging after sintering, it is possible to eliminate voids inside the valve seat 3 in the same manner as infiltration. The material can be discharged effectively.

(Embodiment 2) FIG. 12 shows Embodiment 2 of the present invention, and the method of controlling energization at the time of joining the valve seat 3 and the cylinder head main body 2 is different from that of Embodiment 1 described above.

That is, in this embodiment, a current is not continuously supplied at a constant current value, but a pulse is applied by repeating a large and small current value. The current value on the larger side of the pulse current is constant at about 70 kA,
The smaller current value is set to zero. The energizing time of the large current value pulse is 0.25 to 1 second, and the energizing time of the small current value pulse (time during which no current is flowing) is 0.1 to 1 second.
It is about 0.5 seconds. Furthermore, the number of high current value pulses is 3 to
Nine pulses (four pulses in FIG. 12) are desirable. The time from the start of pressurization to the start of energization of the first large current value pulse and the time from the stop of energization of the last large current value pulse to stop of pressurization are 1.5 seconds, which is the same as in the first embodiment.

FIG. 13 shows a change in the temperature of the valve seat 3 when such pulse current is applied. That is, since the heat capacity of the valve seat 3 made of the Fe-based material is considerably small, the temperature rise due to the resistance heat generation of the valve seat 3 is remarkable. It is harder to dissipate heat than the upper and lower ends, and the contact resistance between the valve seat 3 and the cylinder head body 2 is high when the first large current value pulse is applied. The temperature at the center is equal to or higher than the A1 transformation point when the first large current value pulse is stopped. At this stage, since the valve seat 3 is almost completely embedded in the cylinder head main body 2, it is possible to completely stop the energization. However, the valve seat 3 is kept at a temperature above the A1 transformation point. Since it is rapidly cooled, its center in the vertical direction is baked and its hardness increases.

Therefore, when the temperature is slightly lowered, the second large current value pulse is supplied. At this time, unlike the first energization of the large current value pulse, the contact resistance is reduced by metallurgical bonding, the resistance heating value is reduced, and heat is also released, so even if the current value is the same as the initial value, the temperature is not so much By repeating this process without increasing the hardness, the valve seat 3 hardly increases in hardness.

Therefore, in the second embodiment, the temperature of the central portion in the vertical direction of the valve seat 3 is gradually reduced by the pulse current, so that the hardness of the valve seat 3 does not increase significantly. Deterioration in workability when cutting the peripheral surface portion can be prevented. In addition, it is possible to effectively suppress the valve from being easily worn due to the valve contact surface 3c being too hard.

In the second embodiment, the large current value of the pulse current is fixed and the small current value is set to 0. However, the present invention is not limited to this. For example, as shown in FIG. May be reduced stepwise, and as shown in FIG. 14B, the small current value may be set to an intermediate value between the large current value and 0 without being set to 0. Further, as shown in FIG. 14 (c), after applying the first large current value pulse and then applying the small current value pulse (0 in FIG. 14 (c)), the current value is proportional to time. Alternatively, any energization control may be performed as long as the valve seat 3 can be gradually cooled after the energization of the first large current value pulse is stopped.

Further, in order to improve the heat radiation to the upper electrode 24 of the valve seat 3, it is desirable that the cooling water is passed through the upper electrode 24 and water-cooled. further,
As shown in FIG. 15, a cylindrical projection 31 facing the inner peripheral surface of the valve seat 3 is provided below the upper electrode 24, and is provided on the outer periphery of the projection 31 at substantially equal intervals in the circumferential direction. The cooling water in the upper electrode 24 may be sprayed onto the inner peripheral surface of the valve seat 3 from the plurality of nozzles 32, 32,. This effectively cools the central portion in the vertical direction of the valve seat 3 and can prevent the valve seat 3 from being overheated to the A1 transformation point or higher.

(Embodiment 3) FIG. 16 shows Embodiment 3 of the present invention, in which the method of controlling energization at the time of joining the valve seat 3 and the cylinder head body 2 is different from Embodiments 1 and 2. .

That is, in this embodiment, the joining device 2
0 is a limit switch (not shown) as a seat position detecting means for detecting the position of the valve seat 3 in the height direction.
And the limit switch is operated at a joint position where the valve seat 3 is almost completely embedded in the cylinder head main body 2. Then, after the energization starts, when this limit switch operates,
The current is switched to a constant current value smaller than the initial current value (about 70 kA) at the start of energization. Then, the stop of the energization after the switching is performed in a time, and is stopped in 1.5 to 5 seconds from the start of the energization of the initial current value.

A description will be given of the behavior in the case where the energization control of switching the current value to a small current value in a state where the valve seat 3 is almost completely embedded in the cylinder head body 2 as described above.

First, at the start of energization, as described in the second embodiment, since the temperature of the valve seat 3 is significantly higher than that of the cylinder head body 2 made of an Al-based material, the coefficient of thermal expansion (linear expansion coefficient) is increased. Is smaller than the cylinder head body 2, but the thermal expansion amount is large. For this reason,
When energization is completely stopped in a state where the valve seat 3 is almost completely embedded in the cylinder head main body 2, since the contraction amount of the valve seat 3 is larger than that of the cylinder head main body 2, tensile thermal stress is generated in the valve seat 3. .

Therefore, when the current is switched to a current value smaller than the initial current value and the current is supplied, the temperature of the valve seat 3 gradually decreases as in the second embodiment. On the other hand, since the temperature of the cylinder head body 2 rises due to the heat from the valve seat 3, the temperature difference between the valve seat 3 and the cylinder head body 2 becomes smaller. If the current supply is stopped in this state, the difference in the amount of contraction becomes small, and the thermal stress generated in the valve seat 3 can be reduced.

Therefore, in the third embodiment, the valve seat 3 is switched to a current value smaller than the initial current value in a state where the valve seat 3 is almost completely embedded in the cylinder head main body 2, so that the valve seat 3 and the cylinder head main body are switched. The difference in the amount of thermal expansion (shrinkage) caused by the difference between the heat capacity and the coefficient of thermal expansion of the second element can be reduced. Therefore,
The tensile thermal stress generated in the valve seat 3 can be reduced, and the occurrence of vertical cracks on the inner peripheral surface can be prevented.

In the third embodiment, the current value after switching by the operation of the limit switch is constant. However, the present invention is not limited to this. For example, as shown in FIG. As shown in FIG. 17B, the large current value is smaller than the initial current value after the limit switch is activated, as shown in FIG. Pulse current may be applied. Further, even with the same energization control method as in the second embodiment, the same operation and effect can be obtained.

In the third embodiment, the current value is switched by detecting the position of the valve seat 3 in the height direction by the limit switch. However, a position detecting means such as an optical sensor may be used. May be controlled instead of detecting the time. In this case, it is desirable to switch the current value within 0.25 to 1 second (more preferably, 0.25 to 0.5 second) from the start of energization. In this time, the valve seat 3 is almost completely connected to the cylinder head body 2. It will be switched in the state embedded in.

Further, before joining the valve seat 3 to the cylinder head body 2, the cylinder head body 2 is
It is desirable to preheat to about ° C. By doing so, the temperature difference between them becomes even smaller, and the thermal stress can be kept low. As a result, the valve seat 3
Can reliably be prevented from occurring, and switching of the current value after operation of the limit switch can be made unnecessary. In order to preheat the cylinder head body 2 in this manner, the above-described joining device 20 may be used. That is, the upper and lower electrodes 24 and 25 of the joining device 20 are replaced with carbon electrodes, and the welding power source is turned on with the cylinder head body 2 sandwiched between the electrodes 24 and 25 to perform preheating. . At this time, since both electrodes 24 and 25 are made of carbon, self-heating is large and the cylinder head body 2 can be efficiently preheated. In this way, it is possible to cope with inlining.

As shown in FIG. 18, an upper surface tapered portion 3 d whose height increases toward the inner peripheral surface is provided on the upper portion of the valve seat 3, while the valve seat 3 is provided below the upper electrode 24. A conical concave portion 34 into which the upper tapered portion 3d of the valve seat 3 substantially fits may be formed, and the pressure may be applied while the upper tapered portion 3d of the valve seat 3 is substantially fitted into the concave portion 34 of the upper electrode 24. . That is, when the pressure is applied in this manner, the pressing force acts also in the diameter reducing direction of the valve seat 3, so that even if the temperature of the valve seat 3 rises, the expansion can be prevented, and the cylinder head body 2 Is large, the difference in the amount of shrinkage is small. Therefore, even in this case, generation of a vertical crack in the valve seat 3 can be prevented.

Further, as shown in FIG. 19, chamfered portions 3e, 3e are formed at corners between the inner peripheral surface, the upper surface, and the lower surface in order to reduce stress concentration on the inner peripheral surface of the valve seat 3. It is desirable.

Further, since the inner peripheral surface side of the valve seat 3 is a part to be finally cut off, only the part to be cut off can be sintered as an inexpensive material.

(Embodiment 4) FIG. 20 shows a main part of a joining apparatus 20 according to Embodiment 4 of the present invention (note that the same parts as in FIG. 7 are not described in detail, and only different parts are shown. It will be described), and the energization paths are different from those of the first to third embodiments.

That is, in this embodiment, the joining device 2
0 has a lower electrode 25 as in the first to third embodiments, but this lower electrode 25 is not connected to the welding power source 26 and is used to press the valve seat 3 and the cylinder head body 2. Only used. And the upper electrode 2
4 comprises two first and second electrodes 24a, 24b,
The first electrode 24a is the same as in the first to third embodiments. On the other hand, the second electrode 24b can be vertically moved independently by another pressure cylinder similar to the pressure cylinder 22 for vertically moving the first electrode 24a. Also,
Unlike the first electrode 24a, the second electrode 24b is made of carbon, and both electrodes 24a and 24b are connected to a welding power source 26, respectively.

The first and second electrodes 24a and 24b are
In the same cylinder head body 2, it comes into contact with the upper surfaces of the unjoined valve seat 3 newly joined and the joined valve seat 3 joined previously, respectively. When the welding power source 26 is turned on, the current flows through the first electrode 24a, the unjoined valve seat 3, the cylinder head body 2, the already-joined valve seat 3, and the second electrode 24b in order.
It returns to the welding power source 26. Thus, the already-joined valve seat 3 serves as a return-side energization path when the unjoined valve seat 3 is joined.

Therefore, in the fourth embodiment, when the unjoined valve seat 3 is joined, the resistance heating value is small on the already-joined valve seat 3 side and the internal temperature of the already-joined valve seat 3 is the same as that of the unjoined valve seat 3. However, since the second electrode 24b made of carbon self-heats, even if the already joined valve seat 3 is hardened and hardened as described in the second embodiment. In addition, tempering can be performed appropriately. Moreover, the tempered valve seat 3 can be tempered without increasing the number of steps in-line. Therefore, it is possible to effectively suppress the thermal effect of increasing the hardness of the valve seat 3 at the time of joining.

In the fourth embodiment, the second electrode 24b
Is made of carbon. However, since this is a material having the largest self-heating value, if the temperature of the joined valve seat 3 becomes too high, the second electrode 24b is made of, for example, iron or brass, and tempering is effective. What can be done can be selected.

(Embodiment 5) FIG. 21 shows a piston 41 of a diesel engine as a joining metal member according to Embodiment 5 of the present invention. Piston body 42
A wear-resistant ring 43 (first metal member) made of an Fe-based material is provided on the upper outer peripheral portion of the (second metal member).
The lip in the combustion chamber 42a provided at the upper center of
The e-type (for example, austenitic stainless steel) reinforcing member 44 (first metal member) is joined to each other.

That is, conventionally, the piston body 42 is cast by casting the wear ring 43, but the piston body 4
2 is T6 heat treated to improve its strength,
Since the brittle intermetallic compound of Fe-Al is generated when the wear ring 43 is cast, it is impossible to perform the T6 heat treatment. However, in this embodiment, the piston main body 42 is subjected to T6 heat treatment in advance, and the piston main body 42 is subjected to T6 heat treatment.
Can be joined to the wear ring 43. Even if the wear ring 43 is joined to the piston main body 42 and then subjected to T6 heat treatment, the heat resistance is good and Fe-Al is hardly generated, so there is no problem. Therefore, both the wear resistance and the strength of the piston 41 can be improved.

On the other hand, the wall of the piston body 42 inside the combustion chamber 42a has a problem that cracks are likely to occur particularly at corners. However, in this embodiment, since the reinforcing member 44 is joined to the lip portion in the combustion chamber 42a, it is possible to prevent the occurrence of cracks in the wall portion in the combustion chamber 42a.

(Embodiment 6) FIG. 22 shows a main part of an engine cylinder block 51 as a joining metal member according to Embodiment 6 of the present invention.
In the same manner as in the first embodiment, a rib member 53 (first metal member) made of an Fe-based material is joined to an upper portion of a water jacket 52a of a cylinder block body 52 (second metal member) made of an Al-based material. Be done. Reference numeral 54 denotes a cast iron liner fitted to the inner peripheral surface of the cylinder.

That is, conventionally, the cylinder block 51
In order to improve the rigidity of the cylinder block 52, a rib is integrally formed on the upper portion of the water jacket portion using a sand core at the time of casting of the cylinder block body 52. However, this method requires a long cycle time at the time of casting. And there is a problem that productivity is poor. However, in this embodiment, the rib member 5 is formed while facilitating the casting of the cylinder block body 52.
3 can be joined to the upper part of the water jacket 52a of the cylinder block main body 52 in a short time, and the rigidity of the cylinder block can be improved. For this reason,
The deformation of the liner 54 on the inner peripheral surface of the cylinder can be prevented, and the performance of the engine such as LOC and NVH can be improved. Also, it can be made linerless.

In each of the above embodiments, the first metal member and the second metal member are connected to the diffusion bonding layer 5 and the molten reaction layer 6.
When bonding in a liquid phase diffusion state through the
The notch 28 is provided on the opening side of the support main body 21 on the lower surface of the metal member. In any case of the joining method of joining by pressurization, the above-described implementation is performed by providing the notch 28 on the opening side of the support main body 21 on the lower surface of the upper electrode 24 or attaching an insulating member. The same operation and effect as in the embodiment can be obtained.

[0088]

Next, a specific embodiment will be described. First, as shown in FIG. 23, a test piece 61 was cast from an Al alloy casting (AC4D specified in JIS H5202) as a second metal member. Then, the test piece 61 was subjected to a T6 heat treatment.

Subsequently, as shown in Table 1, the brazing material coating method, the sheet shape, and the taper angle θ of the first joint surface portion
1 were made different to produce five types of Fe-based valve seats (Examples 1 to 5).

In this Table 1, "Friction" in the column of the brazing material coating method is a method of coating by rubbing the brazing material when forming a diffusion bonding layer and a brazing material layer on the surface of the valve seat. That is. On the other hand, the “ultrasonic wave” is a method of coating a brazing material by ultrasonic plating as described in the first embodiment. Further, "thin" in the column of the seat shape means that the valve seat has a shape close to the final shape and is thin, as shown in FIG.
On the other hand, “thick” means that the wall has a large thickness in the same shape as the above embodiment, as shown in FIG.

The materials of the valve seat used were those having the components shown in Table 2. In Table 2, the numerical values are% by weight.
And TC is the total carbon amount (total amount of free carbon (graphite) and carbon of cementite).

Further, the brazing filler metal contains 95% by weight of Zn component, 4.95% by weight of Al component and 0.05% by weight of M
What consisted of a g component was used.

Further, the inside of each valve seat was infiltrated with a Cu-based material, and the surface was plated with Cu.

Each of the valve seats of Examples 1 to 5 was joined to the test piece 61 by a joining device in the same manner as in Embodiment 1. The pressure and current value at the time of this joining were set to the values shown in Table 1. In addition, about a current value,
Since the contact resistance between the valve seat and the test piece 61 changes due to a change in the applied pressure and the like, the embedment depth of the valve seat changes, so that the embedment depth is set to be substantially the same.

For comparison, a thick-walled shape and θ1
= 0.52 rad (30 °) valve seat (C on the surface
u-plated), the applied pressure and the current value were 2
Solid-phase diffusion bonding (pressure welding) was performed at 9420N (3000 kgf) and 70 kA (comparative example).

Next, the joint strength of the valve seats of Examples 1 to 5 and Comparative Example was measured. That is, as shown in FIG. 26, the test piece 61 is placed on the upper surface of the jig base 63 so that the side where the valve seat 62 is joined is on the lower side. To prevent this, the jig table 63 is positioned above a through hole 63a provided substantially at the center of the jig table 63. Then, a cylindrical pressing jig 64 is inserted from above the through hole 61 a of the test piece 61 to push the valve seat 62, and a pulling load when the valve seat 62 comes off from the test piece 61 is measured. This removal load corresponds to the joining strength.

FIG. 27 shows the results of the above-mentioned pulling load measurement test. As a result, by comparing Example 1 and Example 2, the case where the diffusion bonding layer and the brazing material layer are formed on the surface portion of the valve seat by ultrasonic plating is performed by rubbing the brazing material. It can be seen that the bonding strength is improved as compared with the method. This is because the diffusion bonding layer remained on the surface of the valve seat after the test in Example 2 as described later (see FIG. 30), whereas in Example 1, the brazing material layer and the diffusion bonding layer Since almost no trace was observed, it can be estimated that in Example 1, the diffusion bonding layer was not completely formed.

Here, a micrograph (approximately 180 times magnification) of the valve seat surface immediately after the ultrasonic plating in Example 2 is shown in FIG. 28, and the joint surface between the valve seat and the test piece 61 after joining is shown in FIG. Micrograph (approximately 3 magnifications)
FIG. 29 shows a microphotograph (approximately 360 times) of the surface of the valve seat after the pulling load measurement test.
0 is shown. In FIG. 28, the upper side is a valve seat, and the lower side is formed with a brazing material layer via a thin diffusion bonding layer instead of a Cu plating layer. In addition, it turns out that the hole which infiltrated the Cu-based material exists inside the valve seat. In FIG. 29, there is no gap between the upper valve seat and the lower test piece 61, and the diffusion bonding layer and the molten reaction layer are clearly present. Further, in FIG. 30, it can be seen that a thin diffusion bonding layer remains on the surface portion (lower surface portion) of the valve seat.

Further, by comparing Example 2 and Example 3, it can be seen that a thicker valve seat has a greater removal load than a thinner valve seat. This is similar to Example 2
Can be presumed to be due to the fact that the actual pressing force acting on the joint surface has decreased due to the deformation since the corners and the like of the valve seat are deformed.

By comparing Example 3 and Example 4, it can be seen that Example 4 having a larger taper angle θ1 of the first joint surface portion has an oxide film destruction effect as described in Embodiment 1 above. It can be seen that the effect is excellent and the bonding strength increases.

Further, comparing Example 4 and Example 5, it is found that Example 5 having a larger pressing force has higher bonding strength. Moreover, the pressing force is 29420N (3000
It can be seen that by setting to kgf), the joining strength is significantly improved as compared with the comparative example.

FIG. 31 shows an electron micrograph (magnification: about 10,000 times) of the joint surface of the valve seat and the test piece 61 after the joining in Example 5 described above. In this figure, the left side is a valve seat (including a portion that looks white), and the right side is a test piece 61. The gray portions between them are the diffusion bonding layer and the molten reaction layer. It can be seen that the thickness of both layers is about 1 μm. still,
When the elements in both layers were analyzed, Fe, Zn and Al were respectively detected.

In order to investigate the influence of the pressing force in more detail, the pressing force was set to 9807 N (1000 kgf) while the brazing material coating method, the sheet shape, and the taper angle θ1 of the first joint surface were the same as those in the above Examples 4 and 5. , 147
10N (1500kgf) and 29420N (3000
kgf) and set the valve seat to the test piece 61.
And the extraction load was measured in the same manner as in the initial extraction load measurement test.

When the pressing force is 9807 N (1000 kg
The hardness of the test piece 61 after bonding was measured for the test piece f) and that for 29420N (3000 kgf). The measurement of the hardness is based on the fact that the valve seat is moved from the corner between the first joint surface and the second joint surface of the valve seat (point = 0 from the joint surface in FIG. 33) toward the outer peripheral side of the test piece 61. This was performed at predetermined intervals along a direction inclined by about 0.79 rad (45 °) to the side opposite to the joined side.

FIG. 32 shows the results of the above-mentioned pulling load measurement test.
FIG. 33 shows the results of the hardness measurement test. From this, it can be seen that the higher the pressing force, the higher the bonding strength, and the higher the pressing force, the higher the hardness of the test piece 61 near the bonding surface. This is because the higher the applied pressure, the lower the contact resistance and the smaller the calorific value, so that the softening of the test piece 61 is suppressed. When the softening is suppressed, the plastic flow is reliably performed and the oxide film is formed. This is because the effect of the destruction of the brazing material increases and the brazing material is reliably discharged.

Next, in order to examine the effect of the pulse current, the valve seat was joined to the test piece 61 by performing the pulse current. The large current value and the small current value of this pulse conduction were set to 70 kA and 0, respectively. The energizing time of the large current value pulse was 0.5 seconds, and the energizing time of the small current value pulse was 0.1 seconds. Furthermore, the pulse number of the large current value is 6
Pulsed. On the other hand, for comparison, continuous energization (60 k
The valve seat was joined to the test piece 61 by applying a current of A for 2 seconds). The pressure was 29420N for both
(3000 kgf).

[0107] For those joined by pulsed and continuous energization, the hardness before and after joining at the upper and lower ends (A) and the central part (B) in the vertical direction of the valve seat, the test piece 61, respectively. In the direction inclined about 0.79 rad (45 °) from the corner between the first joint surface and the second joint surface of the valve seat toward the outer peripheral side of the test piece 61 toward the side opposite to the side where the valve seat is joined. The hardness and the punching load were measured for each predetermined distance along.

FIG. 34 shows the results of the hardness measurement test before and after the joining. As a result, in the case of joining by continuous energization, the hardness of the central portion (part B) in the vertical direction becomes particularly high after joining, whereas in the case of joining by pulse energization, burning does not occur due to slow cooling. It can be seen that the hardness hardly increased.

FIG. 35 shows the results of a hardness measurement test based on the distance from the joint surface. As a result, it can be seen that the hardness of the test piece 61 is reduced by receiving heat from the valve seat in the case of joining by pulsed electric current.

FIG. 36 shows the results of measurement of the unloading load. From the above, it is possible to reduce the temperature difference between the valve seat and the test piece 61 by radiating the heat to the test piece 61 while suppressing the increase in hardness by performing the slow cooling inside the valve seat by the pulse current, and reducing the shrinkage amount. Can be reduced, and the bonding strength can be improved.

Subsequently, in order to examine how the valve seat is embedded in the test piece 61 in the pulse current application, the embedded amount y is determined according to the time from the start of pressurization.
(See FIG. 37). At this time, the large current value of the pulse current was set to 68 kA, and the small current value was set to 0. Also, the energizing time (H) of the large current value pulse, the energizing time (C) of the small current value pulse, and the number of large current value pulses (N) are variable, and are 0.5 seconds and 0.1 seconds, respectively, under basic conditions. And 6 pulses. Then, a test was performed by changing only one of these basic conditions (see FIG. 38 for the changed conditions).

FIG. 38 shows the results of the embedding amount measurement test. From this, it can be seen that the embedding was almost completed by the first energization of the large current value pulse, and the embedding did not progress in the energization performed later. In addition, the embedding amount hardly changes within the range of the setting conditions of this test. However, when the energizing time of the large current value pulse is as long as 1 second, the embedding amount is slightly larger than at the time of energizing the first large current value pulse than in other cases, and when the number of pulses is as large as 9 pulses, It can be seen that the test piece 61 softens from the middle and the embedding proceeds. Therefore, the condition that the valve seat can be embedded in the first energization of the large current value pulse, and the condition that the slow cooling inside the valve seat and the heat radiation to the cylinder head body can be performed in the energization of the second and subsequent large current value pulses, respectively. Just set it.

Finally, the valve seat is made of a sintered forged material,
This was joined to the test piece 61 by applying a pulse current at a pressing force of 29420 N (3000 kgf). At this time, the large current value of the pulse current was set to 60 kA, and the small current value was set to 0.
Also, the energizing time of the large current value pulse, the energizing time of the small current value pulse, and the number of the large current value pulse are each 0.5 seconds,
0.1 seconds and 4 pulses. In addition, for comparison, Cu
A valve seat made of a sintered material infiltrated with a system material was similarly joined to the test piece 61. However, the large current value of the pulse current was 53 kA. The outer circumference of the test piece 61 is determined from the corner between the first joint surface and the second joint surface of the valve seat in the test piece 61 for the case where the valve seat is a sintered forged material and the case where the valve sheet is a sintered material infiltrated. About 0.79 rad (45 °) on the side opposite to the side where the valve seat is joined toward the side
The hardness was measured at a predetermined distance along the inclined direction.

FIG. 39 shows the result. From this,
It can be seen that the infiltrated sintered material has lower hardness inside the test piece 61. This is because the heat generation inside the valve seat was suppressed by the infiltration of the Cu-based material and the heat generation was effectively performed at the joint surface portion, so that the test piece 61 was softened. However, even if the valve seat is a sintered forged material, the joining is performed well. This can be seen from the micrograph of the joint surface between the sheet and the test piece 61 (approximately 50 times magnification in FIG. 40, FIG.
It can be seen from the magnification of about 400 for 1). This is because the holes inside the valve seat are crushed by forging and have the same effect as infiltration.

[0115]

As described above, according to the first or ninth aspect of the present invention, the first metal member and the second metal member are provided between a pair of supporting portions which are supported in a cantilever manner at the base end and face each other. When the metal member is joined by heat and pressure generated by energization between the two metal members using the two electrodes provided on the both support portions, at least one of the electrodes has a distal end side of the support portion. By forming a non-current-carrying portion in the first portion and performing current-carrying, stabilization of bonding strength can be easily achieved at low cost.

According to the second or tenth aspect of the present invention, the non-conducting portion of the electrode is formed by cutting out a contact portion of the electrode with the first metal member or the second metal member. In the invention according to claim 3 or 11, the non-conductive portion of the electrode is
The electrode is formed by attaching an insulating member to a contact portion of the electrode with the first metal member or the second metal member. Therefore, according to these inventions, a simple specific configuration of the non-conductive portion can be easily obtained.

According to the fourth aspect of the present invention, a diffusion layer of a brazing material having a lower melting point than the first and second metal members and the first metal member is provided in advance at the joint surface of the first metal member. The brazing material layer is formed, and the first metal member and the second metal member are heated and pressed to a temperature equal to or higher than the melting point of the brazing material due to energization between the two metal members. The diffusion layer of the brazing material and the second metal member is formed, and the molten brazing material is discharged from between the joining surfaces of the two metal members, and is joined in a liquid phase diffusion state via the two diffusion layers. Thereby, the joining strength can be stabilized while improving the joining strength between the two metal members.

According to the fifth aspect of the present invention, the first metal member is made of an Fe-based material, the second metal member is made of an Al-based material,
By using a Zn-based material as the brazing material, an optimum combination of materials can be obtained for the joining method according to the fourth aspect of the present invention.

According to the sixth aspect of the present invention, the surface of the first metal member in the brazing material bath is coated with the brazing material by applying ultrasonic vibration, so that the first metal member has a brazing material layer and a diffusion layer. By forming the layer, a diffusion layer between the brazing material and the first metal member can be reliably formed by a simple method, and the joint strength between the two metal members can be further improved. .

According to the seventh aspect of the present invention, the high electrical conductivity material is infiltrated into the first metal member before joining the first metal member and the second metal member. As a result, the joining strength between the two metal members can be effectively improved.

According to the eighth or twelfth aspect of the present invention, the first metal member and the second metal member are joined by plastically flowing the joint surface of the second metal member. The joining strength of the members can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an engine cylinder head as a joining metal member manufactured by a joining device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically illustrating a joined state of a valve seat and a cylinder head main body.

FIG. 3 is a sectional view showing a shape of a valve seat before joining.

FIG. 4 is an explanatory view showing a procedure for joining a valve seat to a cylinder head body.

FIG. 5 is an explanatory view schematically showing a joining process of a valve seat and a cylinder head main body.

FIG. 6 is an explanatory diagram showing a state in which a brazing material is coated by applying ultrasonic vibration to a surface portion of a valve seat in a brazing material bath.

FIG. 7 is a side view showing the joining device.

8 (a) is a view in the direction of arrow VIII in FIG. 7, and FIG. 8 (b)
Is a bottom view of the upper electrode.

FIG. 9 is a timing chart showing a control method of pressurization and energization.

FIG. 10 is a diagram corresponding to FIG. 9 showing another example of the pressurization control method.

FIG. 11 is a phase diagram of an Al—Zn alloy.

FIG. 12 is a diagram corresponding to FIG. 9 showing the second embodiment.

FIG. 13 is a graph showing a temperature change inside a valve seat due to pulsed current.

FIG. 14 is a diagram corresponding to FIG. 9 showing another example of the energization control method.

FIG. 15 is a cross-sectional view showing a state in which cooling water is sprayed on the inner peripheral surface of the valve seat.

FIG. 16 is a diagram corresponding to FIG. 9 showing the third embodiment.

FIG. 17 is a diagram corresponding to FIG. 9, illustrating another example of the energization control method.

FIG. 18 is a cross-sectional view showing a state in which the valve seat is also pressed in the diameter reducing direction to suppress the thermal expansion thereof.

FIG. 19 is a view corresponding to FIG. 3, showing another example of the shape of the valve seat.

FIG. 20 is a cross-sectional view of a main part showing a state where the valve seat and the cylinder head main body are joined by the joining device according to the fourth embodiment.

FIG. 21 is a cross-sectional view illustrating an engine piston as a bonded metal member according to the fifth embodiment.

FIG. 22 is a sectional view showing a main part of a cylinder block of an engine as a joining metal member according to a sixth embodiment.

FIG. 23 is a sectional view showing a test piece.

FIG. 24 is a sectional view showing a thin valve seat.

FIG. 25 is a cross-sectional view showing a thick valve seat.

FIG. 26 is a schematic cross-sectional view showing a procedure of a pulling load measurement test.

FIG. 27 is a graph showing the results of a punching load measurement test on the valve seats of Examples 1 to 5 and Comparative Example.

FIG. 28 is a micrograph showing a state of a valve seat surface immediately after ultrasonic plating.

FIG. 29 is a photomicrograph showing a joint state between a valve seat and a test piece in Example 2.

FIG. 30 is a photomicrograph showing the state of the valve seat surface after the pulling load measurement test.

FIG. 31 is a photomicrograph showing a joint state between a valve seat and a test piece in Example 5.

FIG. 32 is a graph showing the relationship between the welding pressure and the unloading load.

FIG. 33 is a graph showing a change in hardness depending on a distance of a test piece from a bonding surface portion.

FIG. 34 is a graph showing changes in hardness before and after joining of a valve seat in continuous energization and pulse energization.

FIG. 35 is a graph showing a change in hardness depending on a distance from a joint surface of a test piece in continuous energization and pulse energization.

FIG. 36 is a graph showing the results of an extraction load measurement test in continuous energization and pulse energization.

FIG. 37 is an explanatory diagram showing an embedding amount y in an embedding amount measurement test.

FIG. 38 is a graph showing the relationship between the time from the start of pressurization and the embedding amount y.

FIG. 39 is a graph showing a change in hardness according to a distance from a joint surface portion of a test piece in a case where a valve seat is a sintered forged material and in a case where a valve material is an infiltrated sintered material.

FIG. 40 is a micrograph showing a joint state between a valve seat made of a sintered forged material and a test piece.

FIG. 41 is a micrograph showing a further enlarged view of a joint state between a valve seat made of a sintered forged material and a test piece.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Cylinder head main body (2nd metal member) 2a Joining surface 3 Valve seat (1st metal member) 3a 1st joining surface 3b 2nd joining surface 5 Diffusion joining layer (diffusion of brazing material and valve seat) Layer) 6 Molten reaction layer (diffusion layer between brazing material and cylinder head body) 7 Brazing material layer 14 Brazing material bath 20 Joining device 21 Supporting body 21a Upper horizontal part (supporting part) 21b Lower horizontal part (supporting part) 24 Upper electrode 25 Lower electrode 28 Notch (non-conducting part)

[Table 1]

[Table 2]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B23K 20/00 310 B23K 20/00 310A 310M 20/10 20/10 35/28 310 35/28 310D C23C 2/32 C23C 2 / 32 F01L 3/22 F01L 3/22 B F02F 1/24 F02F 1/24 S // B22F 3/26 B22F 3/26 B B23K 103: 20 (72) Inventor Yukihiro Sugimoto No. 3 Fuchu-cho, Fuchu-cho, Aki-gun, Hiroshima Prefecture No. 1 Mazda Co., Ltd. (72) Inventor Shinya Shibata 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd.

Claims (12)

[Claims] A first metal member and a second metal member are provided between a pair of support portions which are supported in a cantilever manner at a base end and face each other. A joining method of joining by heating and pressurization caused by energization between the two metal members using an electrode, wherein a non-energized portion is formed at a tip side of the support portion in at least one of the electrodes, and energization is performed. A method for joining metal members. 2. The method for joining metal members according to claim 1, wherein the non-conductive portion of the electrode is formed by cutting out a contact portion of the electrode with the first metal member or the second metal member. A method for joining metal members, comprising: 3. The method for bonding metal members according to claim 1, wherein an insulating member is attached to a non-conducting portion of the electrode and a contact portion of the electrode with the first metal member or the second metal member. A method for joining metal members, characterized by being formed by: 4. The method for joining metal members according to claim 1, wherein the first metal member has a melting point higher than that of the first metal member and the second metal member. The brazing material layer is formed via a diffusion layer between the low brazing material and the first metal member, and the first metal member and the second metal member are connected to each other by energization between the two metal members. By generating heat and pressurizing to a temperature equal to or higher than the melting point of the brazing material and forming a diffusion layer of the brazing material and the second metal member and discharging the molten brazing material from between the joining surfaces of the two metal members, A method of joining metal members, wherein the joining is performed in a liquid phase diffusion state via both diffusion layers. 5. The method according to claim 4, wherein the first metal member is made of an Fe-based material, the second metal member is made of an Al-based material, and the brazing material is a Zn-based material. A method for joining metal members, comprising: 6. The method according to claim 4, wherein the first metal member in the brazing material bath is coated with a brazing material by applying ultrasonic vibration to the first metal member. A method for joining metal members, comprising forming a brazing material layer and a diffusion layer on the metal member. 7. The method for joining metal members according to claim 1, wherein the first metal member is joined to the second metal member inside the first metal member. A method for joining metal members, comprising infiltrating a high electrical conductivity material in advance. 8. The joining method of a metal member according to claim 1, wherein the joining of the first metal member and the second metal member is performed by plastically flowing the joining surface of the second metal member. A joining method of a metal member. 9. A pair of support portions, which are supported in a cantilever manner on the base end side and face each other, and two electrodes respectively provided on the both support portions, wherein a first electrode is provided between the two support portions. A joining device for joining a metal member and a second metal member by heat and pressure generated by energization between the two metal members using the two electrodes, wherein the support is provided on the at least one electrode. A joining device for a metal member, wherein a non-conducting portion is formed at a tip side of the portion. 10. The metal member joining apparatus according to claim 9, wherein the non-conducting portion of the electrode comprises a cutout portion in a contact portion of the electrode with the first metal member or the second metal member. Characteristic metal member joining device. 11. The metal member joining apparatus according to claim 9, wherein the non-conductive portion of the electrode is an insulating member attached to a contact portion of the electrode with the first metal member or the second metal member. An apparatus for joining metal members, comprising: 12. The metal member joining apparatus according to claim 9, wherein the first metal member and the second metal member are joined by plastically flowing a joining surface portion of the second metal member. A joining device for a metal member, wherein