JP6947704B2 - Welded part forming structure and joining method of metal members - Google Patents

Description

In the present invention, a welded portion forming structure for forming a welded portion for joining the first metal member and the second metal member and a welded portion formed from the welded portion forming structure to form a first metal member and a second metal member. The present invention relates to a method of joining a metal member to be joined with.

For example, in Patent Document 1, the first metal member and the second metal are subjected to resistance welding regardless of a method such as press-fitting having a low degree of freedom in shape design or laser cladding in which usable materials are limited and manufacturing efficiency is low. It is disclosed to form a welded portion with a member. Specifically, the annular first metal member is inserted into the insertion port provided in the second metal member, and the first joint surface of the first metal member and the second joint surface of the second metal member are pressure-welded. Energize while doing. As a result, a welded portion for joining the first joint surface and the second joint surface is formed.

By the way, the shapes of the first metal member and the second metal member may vary at least within the range of processing tolerances. When the contact area when the first joint surface and the second joint surface are brought into contact with each other varies depending on the first metal member and the second metal member due to the influence of this shape variation, the amount of heat generated based on the contact resistance is generated. Also varies. As a result, the joint strength between the first metal member and the second metal member varies, and there is a concern that it becomes difficult to maintain good joint quality by the welded portion.

Therefore, Patent Document 1 proposes to provide an annular convex portion on the second joint surface and bring the apex of the convex portion into line contact with the first joint surface. Even if the above-mentioned shape variation occurs, the contact area between the apex of the convex portion that makes line contact and the first joint surface can be easily maintained constant, so that the calorific value based on the contact resistance varies. It is said that the occurrence is suppressed.

Japanese Unexamined Patent Publication No. 09-79012

The convex portion and the first joint surface are in line contact at the beginning of contact, but when resistance welding progresses and the convex portion is melted, the molten surface of the convex portion and the first joint surface are in surface contact. Further, resistance welding proceeds while the molten convex portion is discharged from between the first joint surface and the second joint surface, and finally, the first joint surface and the second joint surface come into contact with each other and the welded portion. Is formed.

In this way, the contact area between the convex portion and the first joint surface changes according to the progress of resistance welding. Therefore, by simply providing a convex portion on the second joint surface, the first metal member and the second metal member can be maintained in good contact with each other from the start to the end of resistance welding. , It may not be possible to evenly heat the entire contact surface. In the end, the concern that the bonding strength between the first metal member and the second metal member varies cannot be eliminated, and it is still difficult to maintain good bonding quality by the welded portion.

The present invention has been made to solve the above-mentioned problems, and provides a welded portion forming structure capable of forming a welded portion capable of satisfactorily joining the first metal member and the second metal member, and a method for joining the metal member. offer.

In order to achieve the above object, the present invention provides welding for forming a welded portion for joining an annular first metal member and a second metal member having an insertion slot into which the first metal member is inserted. In the portion-forming structure, the first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the insertion port on the outer peripheral surface of the first metal member. A tapered first joint surface that expands in diameter from the tip end side to the base end side in the direction is provided, and a second joint that can form a welded portion with the first joint surface is provided on the inner peripheral surface of the insertion port. In the direction of expanding the diameter of the insertion port from the first starting point on the one end side where the convex portion of the second joint surface rises and the annular convex portion protruding from the surface toward the one end side of the insertion port. The diameter of the insertion port is reduced from the extending tapered first tapered surface and the second starting point on the other end side where the convex portion of the second joint surface rises toward the other end side of the insertion port. A tapered second tapered surface extending in the direction of the insertion is provided, and the convex portion includes a first surface extending from the first starting point toward the center side in the radial direction of the insertion port, and the convex portion. It has a second surface extending from the second starting point toward the extending end of the first surface to form a corner with the first surface, and the apex of the corner and the first starting point. When the radial distance to the portion is A and the radial distance between the apex and the second starting point portion is B, the relationship that satisfies all of A> 0, A ≧ B, and B ≧ 0. The angle formed by the first joint surface with the axial direction of the first metal member and the second joint surface connecting the first starting point portion and the second starting point portion with the shortest distance are the axes of the insertion port. It is characterized in that the direction and the angle formed are equal.

In this welded portion forming structure, since a convex portion is provided on the second joint surface of the second metal member, the first metal member and the first metal member are in a state where the apex of the convex portion is in line contact with the first joint surface. 2 Resistance welding can be started by energizing a metal member while applying a pressure welding load. Therefore, even when the shapes of the first metal member and the second metal member vary, it is possible to suppress the variation in the contact area between the first metal member and the second metal member at the initial contact.

Further, in this welded portion forming structure, the shape of the convex portion is set so as to satisfy the above relationship, the angle formed by the first joint surface with the axial direction of the first metal member, and the second joint surface being the insertion port. It is set so that the axial direction and the angle formed by are equal to each other. As a result, even if resistance welding is carried out while melting the convex portion, the first metal member and the second metal in the radial direction of the insertion port are formed until the first joint surface and the second joint surface come into contact with each other. It is possible to prevent the center of the contact surface with the member from moving from the initial contact position between the apex of the convex portion and the first joint surface to the center side in the radial direction. Therefore, it is possible to prevent the first metal member from being deformed by the pressure welding load during resistance welding.

Therefore, according to this welded portion forming structure, regardless of whether or not the first metal member and the second metal member have variations in shape, the first is from the start to the end of resistance welding. The metal member and the second metal member can be brought into good contact with each other. As a result, it is possible to suppress variations in the bonding strength between the first metal member and the second metal member, so that the bonding quality of the welded portion can be maintained satisfactorily. In other words, it is possible to form a welded portion capable of satisfactorily joining the first metal member and the second metal member.

The present invention is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted. The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the proximal end side in the insertion direction into the insertion port. A tapered first joint surface that expands in diameter toward A tapered first portion extending in a direction of expanding the diameter of the insertion port from the first starting point portion on the one end side on which the convex portion of the second joint surface rises to the one end side of the insertion port. A tapered surface extending from a second starting point on the other end side where the convex portion of the second joint surface rises toward the other end side of the insertion port in a direction of reducing the diameter of the insertion port. The second tapered surface is provided, and the convex portion has a first surface extending from the first starting point portion toward the center side in the radial direction of the insertion port, and the first surface from the second starting point portion. It has a first surface extending toward the extending end of the surface and a second surface forming a corner portion, and the insertion on the inner corner side of the corner portion through the apex of the corner portion. When α is the angle formed by the reference line along the axial direction of the mouth and the first surface, and β is the angle formed by the reference line and the second surface, α> 0, α ≧ β, β ≧ 0. A relationship that satisfies all of the above is established, and the angle formed by the first joint surface with the axial direction of the first metal member and the second joint surface connecting the first starting point portion and the second starting point portion at the shortest distance. Is equal to the axial direction of the insertion slot.

Even in this welded portion forming structure, regardless of whether or not the first metal member and the second metal member have variations in shape, the first metal member and the first metal member are used from the start to the end of resistance welding. The second metal member can be brought into good contact with the second metal member. As a result, it is possible to form a welded portion capable of satisfactorily joining the first metal member and the second metal member.

The present invention is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted. The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the base end side in the insertion direction into the insertion port. A first joint surface having a tapered portion whose diameter increases toward the surface is provided, and the inner peripheral surface of the insertion port is a circle protruding from the second joint surface capable of forming a welded portion with the first joint surface. An annular convex portion is provided, and the convex portion extends from the first starting point portion on the one end side on which the convex portion of the second joint surface rises toward the center side in the radial direction of the insertion port. The surface and the convex portion of the second joint surface extend from the second starting point portion on the other end side toward the extending end portion of the first surface to form a corner portion with the first surface. The second surface has a second surface, and the length from the first starting point portion of the first surface to the apex of the corner portion is L1 in a cross section along the axis of the insertion port. When the length from the starting point to the apex is L2, the relationship of 0.7 × L2 ≦ L1 ≦ 1.3 × L2 is established.

In this welded portion forming structure, since the convex portion is provided on the second joint surface of the second metal member, even if the shape of the first metal member and the second metal member varies, even if the shape of the first metal member and the second metal member vary. It is possible to suppress the variation in the contact area between the first metal member and the second metal member at the initial contact.

Further, in this welded portion forming structure, by setting the shape of the convex portion as described above, even if resistance welding is carried out while melting the convex portion, the length of the current path (energization distance) is convex. It is possible to suppress the variation in each part. Therefore, it is possible to suppress the occurrence of a temperature difference in the contact surface between the first metal member and the second metal member during resistance welding.

Therefore, according to this welded portion forming structure, regardless of whether or not the first metal member and the second metal member have variations in shape, the first is from the start to the end of resistance welding. The contact surface between the metal member and the second metal member can be heated substantially evenly. As a result, it is possible to suppress the variation in the bonding strength between the first metal member and the second metal member, and to maintain good bonding quality by the welded portion. In other words, it is possible to form a welded portion capable of satisfactorily joining the first metal member and the second metal member.

In the welded portion forming structure, the L1 and the L2 may be substantially equal. In this case, it is possible to form a welded portion capable of satisfactorily joining the first metal member and the second metal member with a simple structure.

In the welded portion forming structure, the angle formed by the radial direction of the insertion port and the surface direction of the first surface is γ, and the angle formed by the axial direction of the insertion port and the surface direction of the second surface is δ. when a, 0 ° <γ = δ <is made elevational one 45 ° relationship. In this case, it is possible to reduce the amount of the molten convex portion discharged from between the first joint surface and the second joint surface during resistance welding. This makes it possible to reduce the energy required to form the weld.

In the welded portion forming structure, a group in which the inner peripheral surface of the first metal member extends along the axial direction of the first metal member and a group which is an end surface on the base end side of the first metal member. The direction in which the end surface extends along the radial direction of the first metal member intersects at the intersection, and the end portion of the inner peripheral surface of the first metal member on the base end side coincides with the intersection. Or, the end of the base end surface on the radial center side of the first metal member, which is separated from the intersection to the tip side of the first metal member, coincides with the intersection, or Separated from the intersection to the outside in the radial direction of the first metal member, the distance between the tip end side of the inner peripheral surface of the first metal member and the intersection is a, and the base end surface of the base end surface. Let b be the distance between the radial outer end of the first metal member and the intersection, and the distance between the radial center end of the first metal member and the intersection of the base end surface. when to is c, is made elevational one relationship that satisfies all of the b / a ≧ 1, b / 3 ≧ c ≧ 0.

In this case, since the rigidity of the first metal member with respect to the pressure welding load can be satisfactorily increased, it is possible to more effectively suppress the deformation of the first metal member during resistance welding. As a result, resistance welding can be performed while the first metal member and the second metal member are in good contact with each other, so that the joining quality of the welded portion can be further improved.

In the welded portion forming structure, it is preferable that the first metal member is made of an iron-based material and the second metal member is made of an aluminum-based material. For example, in a structure in which a first metal member is built up on a second joint surface to form a welded portion by a laser clad method, there are many restrictions on the materials applicable as the first metal member and the second metal member. However, in the welded portion forming structure according to the present invention, since various materials capable of resistance welding can be used as the first metal member and the second metal member, the first metal member is made of an iron-based material and is the first. (2) Even when the metal member is made of an aluminum-based material, the welded portion can be formed satisfactorily. By using an iron-based material, it is possible to improve the wear resistance of the first metal member, and by using an aluminum-based material, it is possible to reduce the weight of the second metal member.

In the welded portion forming structure, the first metal member is a valve seat, the second metal member is a cylinder head main body, and the insertion port is an opening peripheral edge of a port provided in the cylinder head main body. It is preferably a part. In this welded portion forming structure, it is possible to form a welded portion by resistance welding to join the first joint surface of the valve seat and the second joint surface of the cylinder head body. Therefore, unlike the case where the valve seat and the cylinder head main body are joined by press fitting or shrink fitting, sufficient joining strength can be obtained in a small fixed space. In other words, because the thickness of the valve seat can be reduced, the degree of freedom in the shape of the port can be improved, and the distance between the valve contact surface of the valve seat and the cooling jacket can be shortened to improve the cooling efficiency of the valve, etc. It becomes possible to raise it.

Further, the present invention is a joining method of a metal member for forming the welded portion from the welded portion forming structure and joining the first metal member and the second metal member to the first joint surface. By energizing the first metal member and the second metal member while applying a pressure welding load, the molten convex portion is brought into contact with the first joint surface and the first metal member. 2. It is characterized by having a step of bringing the first metal member and the second metal member close to each other and bringing the first joint surface into contact with the second joint surface while discharging from between the two joint surfaces. And.

According to this method of joining the metal members, the first metal member and the second metal member are in good contact with each other regardless of whether or not the first metal member and the second metal member have variations in shape. It can be heated to form a welded portion with excellent joining quality. As a result, the first metal member and the second metal member can be satisfactorily joined to obtain a joined body.

According to the welded portion forming structure and the joining method of the metal member of the present invention, a welded portion capable of satisfactorily joining the first metal member and the second metal member can be formed, and a joined body having excellent joining strength can be obtained. ..

It is sectional drawing of the valve seat (first metal member) and cylinder head body (second metal member) of the weld | welded part formation structure which concerns on 1st Embodiment of this invention. It is an enlarged view of the main part of the valve seat of FIG. It is an enlarged view of the main part of the cylinder head main body of FIG. It is schematic cross-sectional view of the main part of the cylinder head obtained by applying the welded part formation structure of FIG. It is explanatory drawing explaining the state that the 1st joint surface of the valve seat of FIG. 2 and the convex portion provided on the 2nd joint surface of the cylinder head main body of FIG. 3 were brought into contact with each other. It is explanatory drawing explaining the state that the valve seat and the cylinder head main body were brought close to each other by melting the convex part of FIG. It is explanatory drawing explaining the state that the valve seat of FIG. 6 and the cylinder head main body are made closer to each other, and the welded part which joins a 1st joint surface and a 2nd joint surface is formed. It is explanatory drawing explaining the position of the contact position P1 of FIG. 5, the contact surface center P2 of FIG. 6, and the contact surface center P3 of FIG. 7 in relation to the valve seat before the welded portion is formed. It is a graph which shows the relationship between the displacement amount in the radial direction from the contact position P1 of the contact surface center P2, and the deformation amount of the first joint surface by a pressure contact load. It is an enlarged view of the main part of the valve seat which concerns on the modification of 1st Embodiment. FIG. 11A is an enlarged view of a main part of the cylinder head main body according to the modified example of the first embodiment, and FIG. 11B is an enlarged view of a main part of the cylinder head main body according to another modified example. It is sectional drawing of the valve seat and the cylinder head main body of the welded part formation structure which concerns on 2nd Embodiment of this invention. It is an enlarged view of the main part of the cylinder head main body of FIG. It is explanatory drawing explaining the state that the convex part provided on the 2nd joint surface of the cylinder head main body was brought into contact with the 1st joint surface of the valve seat of FIG. It is explanatory drawing explaining the state that the valve seat and the cylinder head main body were brought close to each other by melting the convex part of FIG. It is explanatory drawing explaining the state that the valve seat of FIG. 15 and the cylinder head main body were made closer to each other, and the welded part which joins a 1st joint surface and a 2nd joint surface was formed. FIG. 17A is a graph showing the results of the displacement amount measurement tests of Examples 1 and 2, and FIG. 17B is a graph showing the results of the joint strength measurement tests of Examples 1 and 2. FIG. 18A is a graph showing the results of the displacement amount measurement tests of Examples 3 and 4, and FIG. 18B is a graph showing the results of the joint strength measurement tests of Examples 3 and 4. It is a graph which shows the result of the joint strength measurement test of Examples 5 and 6.

Suitable embodiments of the welded portion forming structure and the method of joining metal members according to the present invention will be described in detail with reference to the accompanying drawings. In the following figures, components having the same or similar functions and effects may be designated by the same reference numerals, and repeated description may be omitted.

In the following, as shown in FIGS. 1 to 4, the welded portion forming structure 10 according to the first embodiment includes a first metal member 14 which is a valve seat 12 and a second metal member 18 which is a cylinder head main body 16. An example for forming a welded portion 20 (see FIG. 4) for joining the above will be described. That is, the welded portion 20 is formed from the welded portion forming structure 10 by the joining method of metal members according to the first embodiment (hereinafter, also simply referred to as a joining method), and the valve seat 12 and the cylinder head main body 16 are joined. Then, the cylinder head 22 shown in FIG. 4 is obtained.

However, the first metal member 14 and the second metal member 18 to which the welded portion forming structure 10 according to the present invention can be applied are not limited to the valve seat 12 and the cylinder head main body 16. The valve seat 12 is a second metal member 18 having an annular first metal member 14 and an insertion port 24 into which the first metal member 14 is inserted, and is made of a material capable of resistance welding. And the welded portion forming structure 10 can be applied in the same manner as the cylinder head main body 16.

First, the cylinder head 22 having the valve seat 12 and the cylinder head main body 16 after forming the welded portion 20 will be described with reference to FIG. The valve seat 12 is, for example, an annular body made of a sintered body of an iron-based material such as a steel material. The valve seat 12 may further contain a high electrical conductivity material such as a copper-based material.

The cylinder head body 16 is made of, for example, an aluminum-based material such as pure aluminum or an aluminum alloy. The cylinder head main body 16 is formed with an intake port 28 and an exhaust port 30 (hereinafter, collectively referred to as ports) whose one end side opens toward the combustion chamber 26, respectively. The opening peripheral edge portion 32 of these ports serves as an insertion port 24, and the valve seat 12 is joined to the cylinder head main body 16 via the welded portion 20 in a state of being inserted into the opening peripheral edge portion 32, respectively. Specifically, the first joint surface 34 provided on the outer peripheral surface 33 of the valve seat 12 and the second joint surface 36 provided on the inner peripheral surface of the opening peripheral edge portion 32 form the welded portion 20. ..

Each of the ports can be opened and closed by seating or separating the valve 40 from the valve contact surface 38 of the valve seat 12 joined to the opening peripheral edge portion 32 of the cylinder head main body 16. Further, a cooling jacket 42 for circulating cooling water is provided between the intake port 28 and the exhaust port 30 of the cylinder head main body 16, and the heat of the valve 40 is cooled through the valve seat 12 and the cylinder head main body 16. By transmitting to the jacket 42, it is possible to satisfactorily cool the valve 40 and the like.

Next, the welded portion forming structure 10 for forming the welded portion 20 will be described with reference to FIGS. 1 to 3. That is, the valve seat 12 and the cylinder head main body 16 before forming the welded portion 20 will be described. The opening peripheral edge portion 32 and the valve seat 12 shown in FIG. 1 are arranged so that their axial directions (arrows X1 and X2 directions) coincide with each other and their radial directions (arrow Y directions) are parallel to each other. There is. Further, the valve seat 12 is inserted from one end side (arrow X1 side, hereinafter simply referred to as one end side) of the opening peripheral edge portion 32 in the axial direction toward the other end side (arrow X2 side, hereinafter simply referred to as the other end side). Will be done.

In the following, with respect to the valve seat 12, the tip end side (arrow X2 side) of the insertion direction (arrow X2 direction) when the valve seat 12 is inserted into the opening peripheral edge portion 32 is also simply referred to as the tip end side (arrow X1). The side) is also simply referred to as the base end side. Further, the outer side of the valve seat 12 and the opening peripheral edge portion 32 in the radial direction (arrow Y direction) is also referred to simply as the outer side, and the central side is also simply referred to as the central side.

As shown in FIGS. 1 and 2, the tip surface 44 of the valve seat 12 has a tapered shape that increases in diameter from the tip side to the base end side. The outer peripheral surface 33 of the valve seat 12 is provided with a tapered first joint surface 34 whose diameter increases from the tip end side to the base end side. The inner peripheral surface 48 of the valve seat 12 extends along the axial direction, and the proximal end surface 50 of the valve seat 12 extends along the radial direction of the valve seat 12.

As shown in FIG. 2, the extending direction of the inner peripheral surface 48 of the valve seat 12 and the extending direction of the base end surface 50 of the valve seat 12 intersect at the intersection Z. In the present embodiment, the intersection Z coincides with both the proximal end 52 of the inner peripheral surface 48 of the valve seat 12 and the central end 54 of the proximal surface 50.

In the valve seat 12, the distance between the end portion 56 on the distal end side of the inner peripheral surface 48 and the intersection Z is a, the distance between the outer end 56 of the proximal end surface 50 and the intersection Z is b, and the proximal end surface 50 When the distance between the end portion 54 on the center side and the intersection Z (see FIG. 10) is c (see FIG. 10), a relationship that satisfies all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 is established. In the present embodiment, as described above, since the end portion 54 on the center side of the base end surface 50 and the intersection portion Z coincide with each other, c = 0.

As shown in FIGS. 1 and 3, a convex portion 58, a first tapered surface 60, and a second tapered surface 62 are provided on the inner peripheral surface of the opening peripheral edge portion 32. As described above, the convex portion 58 projects in an annular shape from the second joint surface 36 on which the first joint surface 34 of the valve seat 12 and the welded portion 20 (see FIG. 4) can be formed. The first tapered surface 60 has a tapered shape extending in the direction of expanding the diameter of the opening peripheral edge portion 32 from the first starting point portion 64 on the one end side on which the convex portion 58 of the second joint surface 36 rises toward one end side in the axial direction. Is. The second tapered surface 62 extends in a direction in which the opening peripheral edge portion 32 is reduced in diameter from the second starting point 66 on the other end side on which the convex portion 58 of the second joint surface 36 rises toward the other end side in the axial direction. It is tapered.

As shown in FIG. 3, the convex portion 58 has a first surface 68 extending from the first starting point portion 64 toward the radial center side of the opening peripheral edge portion 32, and a first surface 68 from the second starting point portion 66 to the first surface portion 68. It has a first surface 68 extending toward the extending end portion of the surface and a second surface 70 forming a corner portion. When the radial distance between the apex 72 of the corner and the first starting point 64 is A and the radial distance between the apex 72 and the second starting point 66 is B, A> 0, A ≧ B, B A relationship that satisfies all of ≧ 0 is established. Further, on the inner angle side of the corner portion, the angle formed by the reference line L and the first surface 68 along the axial direction of the opening peripheral edge portion 32 through the apex 72 is defined as α, and the reference line L and the second surface 70 form each other. When the angle is β, a relationship that satisfies all of α> 0, α ≧ β, and β ≧ 0 is established.

As shown in FIG. 1, with respect to the valve seat 12 and the opening peripheral edge portion 32, the angle formed by the first joint surface 34 with the axial direction of the valve seat 12 is set to θ1, and the first starting point portion 64 and the second starting point portion 66 are set to the shortest distance. When the angle formed by the connecting second joint surface 36 with the axial direction of the opening peripheral edge portion 32 is θ2, θ1 and θ2 are set to be equal to each other. The setting for making θ1 and θ2 equal here includes the case where θ1 and θ2 are made substantially equal.

The tip surface 44 of the valve seat 12 and the second tapered surface 62 of the opening peripheral edge portion 32 are valved when the tip surface 44 and the second tapered surface 62 come into contact with each other by making the taper angles substantially equal to each other. Each shape is set so that the seat 12 and the cylinder head main body 16 have a desired joint positional relationship.

Next, a joining method of forming the welded portion 20 from the welded portion forming structure 10 and joining the valve seat 12 and the cylinder head main body 16 will be described with reference to FIGS. 5 to 8.

In this joining method, first, as shown in FIG. 5, the valve seat 12 and the cylinder head main body 16 are set between a set of electrodes including an electrode 74 and an electrode (not shown). At this time, the tip surface 44 of the valve seat 12 and the second tapered surface 62 of the opening peripheral edge portion 32 are brought to face each other at intervals, and the apex 72 of the convex portion 58 is brought into contact with the first joint surface 34. As a result, when the first joint surface 34 and the apex 72 are in line contact, the contact position in the radial direction of the opening peripheral edge portion 32 is set to P1.

A set of electrodes is connected to a power source via, for example, a capacitor, and can be driven in a direction close to or separated from each other by a drive mechanism such as a pressure cylinder (both not shown). Therefore, by driving this set of electrodes in the directions close to each other, a pressing force (pressure contact load) can be applied to the valve seat 12 and the cylinder head main body 16 in the directions close to each other. By energizing the valve seat 12 and the cylinder head body 16 while applying the pressure welding load in this way, resistance welding can be started.

That is, the contact portion between the valve seat 12 and the cylinder head main body 16 generates heat based on the contact resistance. As a result, when the melting point of the cylinder head body 16 (convex portion 58) is reached, the convex portion 58 begins to melt. As a result, as shown in FIG. 6, the valve seat 12 and the cylinder head main body 16 can be brought close to each other while discharging the molten convex portion 58 from between the first joint surface 34 and the second joint surface 36. can. At this time, the molten convex portion 58 and the first joint surface 34 come into surface contact with each other. The radial center of the contact surface between the valve seat 12 and the cylinder head body 16 (hereinafter, also simply referred to as the contact surface center) P2 is arranged radially outside the contact position P1 at the initial contact.

As shown in FIG. 7, when substantially the entire convex portion 58 is melted, the first joint surface 34 and the second joint surface 36 come into contact with each other to form the welded portion 20, and the tip surface 44 and the second tapered surface are formed. It comes into contact with 62. At this time, the contact surface center P3 between the valve seat 12 and the cylinder head main body 16 is arranged on the radial center side of the contact surface center P2.

That is, even if resistance welding is carried out while melting the convex portion 58, as shown in the explanatory view of FIG. 8, the contact surface center until the first joint surface 34 and the second joint surface 36 come into contact with each other. It is avoided that P2 moves to the center side in the radial direction from the contact position P1.

Further, when the tip surface 44 and the second tapered surface 62 are in contact with each other, the valve seat 12 and the cylinder head body 16 are brought into contact with each other as compared with the case where only the first joint surface 34 and the convex portion 58 are in contact with each other. The contact area increases rapidly. Therefore, the current value per unit area flowing between the valve seat 12 and the cylinder head main body 16 becomes small (contact resistance becomes small). As a result, the amount of heat generated on the contact surface between the valve seat 12 and the cylinder head body 16 is reduced. As a result, it becomes impossible to obtain the amount of heat required to melt the cylinder head main body 16, and the melting of the cylinder head main body 16 is temporarily stopped.

Therefore, by stopping the energization immediately before the tip surface 44 and the second tapered surface 62 come into contact with each other, or at the same timing as the contact, the cylinder head main body 16 is further melted, in other words, the second tapered surface 62. Can be avoided from melting. As a result, resistance welding can be completed with the tip surface 44 and the second tapered surface 62 in contact with each other.

As described above, the shapes of the tip surface 44 and the second tapered surface 62 are set so that the valve seat 12 and the cylinder head body 16 have a desired positional relationship when they come into contact with each other. Therefore, by forming the welded portion 20 as described above, the valve seat 12 and the cylinder head main body 16 can be joined in a desired positional relationship. After that, the valve seat 12 is machined to form the valve contact surface 38, whereby the cylinder head 22 is obtained (see FIG. 4). That is, in this cylinder head 22, the welded portion 20 is formed by the first joint surface 34 and the second joint surface 36, and the tip surface 44 and the second tapered surface 62 are non-melted portions that only abut against each other. Will be.

Next, the effects of the welded portion forming structure 10 and the joining method according to the first embodiment will be described. In the welded portion forming structure 10, since the convex portion 58 is provided on the second joint surface 36 of the opening peripheral edge portion 32 as described above, the apex 72 of the convex portion 58 is in line contact with the first joint surface 34. Then, resistance welding can be started. As a result, even if the shapes of the valve seat 12 and the cylinder head body 16 vary, it is possible to prevent the contact area between the valve seat 12 and the cylinder head body 16 at the time of contact from varying.

Further, the welded portion forming structure 10 is convex so that a relationship satisfying all of A> 0, A ≧ B, and B ≧ 0, or a relationship satisfying all of α> 0, α ≧ β, and β ≧ 0 is established. The shape of the portion 58 is set, and the shapes of the valve seat 12 and the cylinder head main body 16 are set so that θ1 and θ2 are equal to each other. As a result, as described above, even if resistance welding is carried out while melting the convex portion 58, the contact surface center P2 is at the contact position until the first joint surface 34 and the second joint surface 36 come into contact with each other. It is possible to avoid moving to the center side in the radial direction from P1. As a result, it is possible to effectively suppress the deformation of the valve seat 12 due to the pressure welding load during resistance welding.

This is clear from the graph shown in FIG. The horizontal axis of this graph indicates the amount of displacement in the radial direction of the contact surface center P2 with respect to the contact position P1. Further, the vertical axis of this graph shows the amount of displacement in the radial direction of the end portion 76 (see FIGS. 2, 5, etc.) on the base end side of the first joint surface 34 with respect to the reference position. The reference position is the radial position of the end portion 76 at the time when the first joint surface 34 and the apex 72 are brought into contact with each other (see FIG. 5). That is, from the values shown on the vertical axis, the amount of deformation of the first joint surface 34 of the valve seat 12 due to the pressure contact load can be known.

From FIG. 9, as the center P2 of the contact surface moves to the center side in the radial direction, the end portion 76 of the first joint surface 34 is displaced to the outside in the radial direction, that is, the base end side of the valve seat 12 is radially outward. It can be seen that it bends greatly toward the outside of. On the other hand, when the contact surface center P2 moves outward in the radial direction, the amount by which the end portion 76 of the first joint surface 34 is displaced toward the radial center side is such that the contact surface center P2 moves toward the radial center side. It is significantly smaller than the displacement amount of the end portion 76 in the case of That is, it can be seen that the deformation of the valve seat 12 can be suppressed by preventing the contact surface center P2 from moving toward the center side in the radial direction.

Further, in the welded portion forming structure 10, the shape of the valve seat 12 is set so that a relationship satisfying all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 is established. As a result, the rigidity of the valve seat 12 with respect to the pressure welding load can be satisfactorily increased, so that deformation of the valve seat 12 during resistance welding can be more effectively suppressed.

From the above, regardless of whether or not the shapes of the valve seat 12 and the cylinder head body 16 are uneven, the valve seat 12 and the cylinder head body 16 are satisfactorily maintained from the start to the end of resistance welding. Can be contacted. As a result, it is possible to suppress variations in the bonding strength between the valve seat 12 and the cylinder head body 16, so that the bonding quality of the welded portion 20 can be maintained satisfactorily. As a result, the welded portion 20 having excellent joint strength can be formed.

By the way, for example, in the structure in which the valve seat 12 is built up on the second joint surface 36 to form the welded portion 20 by the laser clad method, there are many restrictions on the materials applicable to the valve seat 12 and the cylinder head main body 16. However, in the welded portion forming structure 10, various materials capable of resistance welding can be used as the valve seat 12 and the cylinder head main body 16. Therefore, as described above, even when the valve seat 12 is made of an iron-based material and the cylinder head body 16 is made of an aluminum-based material, the welded portion 20 can be formed satisfactorily. By using an iron-based material, it is possible to improve the wear resistance of the valve seat 12, and by using an aluminum-based material, it is possible to reduce the weight of the cylinder head body 16.

In the welded portion forming structure 10, it is possible to form the welded portion 20 by resistance welding to join the first joint surface 34 of the valve seat 12 and the second joint surface 36 of the cylinder head main body 16. Therefore, unlike the case where the valve seat 12 and the cylinder head main body 16 are joined by press fitting, shrink fitting, or the like, sufficient joining strength can be obtained in a small fixed space. That is, since the thickness of the valve seat 12 can be reduced, the degree of freedom in the shape of the port can be improved, or the distance between the valve contact surface 38 of the valve seat 12 and the cooling jacket 42 can be shortened to reduce the valve 40. It becomes possible to improve the cooling efficiency of the above (see FIG. 4).

In the welded portion forming structure 10 according to the first embodiment, the valve seat 12 is not limited to the shape shown in FIG. 2, and various deformations occur within a range where θ1 becomes equal to θ2 (see FIG. 1). It is possible. For example, as in the valve seat 78 shown in FIG. 10, the notch 80 may be provided on the proximal end side of the inner peripheral surface 48 and the central side of the proximal end surface 50. In the valve seat 78, unlike the valve seat 12 described above, the end portion 52 on the proximal end side of the inner peripheral surface 48 is separated from the intersection Z toward the distal end side, and the end portion 54 on the central end side of the proximal end surface 50 is the intersection. Since it is separated from Z to the outside, c> 0. Also in this case, it is preferable that a relationship that satisfies all of b / a ≧ 1 and b / 3 ≧ c> 0 is established. As a result, similarly to the valve seat 12 described above, the rigidity of the valve seat 78 with respect to the pressure welding load can be satisfactorily increased, so that deformation of the valve seat 78 during resistance welding can be more effectively suppressed. Become.

Further, the convex portion 58 provided on the opening peripheral edge portion 32 of the cylinder head main body 16 is not limited to the shape shown in FIG. 3, and has a relationship that satisfies all of A> 0, A ≧ B, and B ≧ 0. Various modifications are possible as long as the relationship that satisfies all of α> 0, α ≧ β, and β ≧ 0 is established. For example, B = 0 may be set as shown in the convex portion 82 shown in FIG. 11A. In this case, β = 0 and α = 90 °. Further, as in the convex portion 84 shown in FIG. 11B, the first surface 68 may have a tapered shape extending in the direction of expanding the diameter of the opening peripheral edge portion 32 from the apex 72 toward the first starting point portion 64.

Even when the cylinder head main body 16 is provided with the convex portions 82 and 84 having the shapes shown in FIGS. 11A and 11B, the same action and effect as when the convex portions 58 are provided can be obtained. That is, even if the shapes of the valve seat 12 and the cylinder head body 16 vary, the welded portion 20 having excellent joint strength can be formed.

Next, the welded portion forming structure 100 according to the second embodiment will be described with reference to FIGS. 12 to 16. Similar to the first embodiment, in the second embodiment as well, the welded portion forming structure 100 is welded to join the first metal member 104 which is the valve seat 102 and the second metal member 108 which is the cylinder head main body 106. An example for forming the part 110 (see FIG. 16) will be described, but the present invention is not particularly limited thereto.

That is, the cylinder head (not shown) can also be obtained by forming the welded portion 110 from the welded portion forming structure 100 and joining the valve seat 102 and the cylinder head main body 106 by the joining method according to the second embodiment. In this cylinder head, instead of the valve seat 12, the cylinder head main body 16 and the welded portion 20 shown in FIGS. 1 and 7, the valve seat 102, the cylinder head main body 106 and the welded portion shown in FIGS. 12 and 16 are replaced. Since the cylinder head 22 is configured in the same manner as the cylinder head 22 except that the cylinder head 22 is provided, a detailed description thereof will be omitted.

The valve seat 102 is configured in the same manner as the valve seat 12 (see FIG. 1) except for the shapes of the front end surface 112 and the outer peripheral surface 114. The valve seat 102 may be configured in the same manner as the valve seat 78 (see FIG. 10) except for the shapes of the front end surface 112 and the outer peripheral surface 114.

The surface direction of the tip surface 112 is along the radial direction of the valve seat 102. The outer peripheral surface 114 of the valve seat 102 is provided with a first tapered portion 116 and a second tapered portion 118 having different surface directions from each other. Each of the first tapered portion 116 and the second tapered portion 118 has a tapered shape in which the diameter increases from the distal end side toward the proximal end side. The first tapered portion 116 is arranged closer to the tip end side than the second tapered portion 118, and the base end of the first tapered portion 116 and the tip end of the second tapered portion 118 coincide with each other. The tip of the first tapered portion 116 coincides with the outer end of the tip surface 112. As shown in FIG. 16, in the valve seat 102, a part of the outside of the tip surface 112, the whole of the first tapered portion 116, and a part of the other end side (arrow X2 side) of the second tapered portion 118. Is the first joint surface 120.

The shape of the outer peripheral surface 114 of the valve seat 102 is not limited to the above. One tapered portion may be provided in place of the two first tapered portions 116 and the second tapered portion 118 having different surface directions from each other, or three or more tapered portions are provided. You may. Further, the shape of the first joint surface 120 is not limited to the above. The first joint surface 120 may be provided on at least a part of the outer peripheral surface 114 of the valve seat 102.

The cylinder head main body 106 is configured in the same manner as the cylinder head main body 16 except for the shape of the inner peripheral surface of the opening peripheral edge portion 32. As shown in FIGS. 12 and 13, in the cylinder head main body 106 before joining with the valve seat 102, the first joining surface 120 of the valve seat 102 and the welded portion 110 (FIG. 16) are on the inner peripheral surface of the opening peripheral edge portion 32. A convex portion 124 projecting in an annular shape from the second joint surface 122 capable of forming (see) and a tapered surface 126 are provided.

As shown in FIG. 16, the second joint surface 122 has a shape capable of following the first joint surface 120 of the valve seat 102 when the welded portion 110 is formed. Further, in the cylinder head main body 106 according to the second embodiment, the inner peripheral surface of the port is from the end portion on the radial center side to the other end side of the second joint surface 122.

As shown in FIG. 13, the tapered surface 126 expands the diameter of the opening peripheral edge portion 32 from the first starting point portion 128 on the one end side (arrow X1 side) on which the convex portion 124 of the second joint surface 122 rises to the one end side. It has a tapered shape extending in the direction of the arrow. Further, as shown in FIG. 16, the tapered surface 126 and the second tapered portion 118 of the valve seat 102 are formed by, for example, making the taper angles of the tapered surfaces 126 and the second tapered portion 118 substantially equal to each other. Each shape is set so that the valve seat 102 and the cylinder head main body 106 have a desired joint positional relationship when they come into contact with each other. As shown in FIG. 13, the second starting point 130 on the other end side on which the convex portion 124 of the second joint surface 122 rises coincides with the central end portion of the second joint surface 122.

The convex portion 124 has a first surface 132 extending from the first starting point 128 toward the center side, and a first surface extending from the second starting point 130 toward the extending end of the first surface 132. It has 132 and a second surface 134 forming a corner. The length from the first starting point 128 of the first surface 132 to the apex 136 of the corner portion is L1 in the cross section along the axial direction of the opening peripheral edge portion 32 (insertion port 24), and the second starting point of the second surface 134. When the length from the portion 130 to the apex 136 is L2, the relationship of 0.7 × L2 ≦ L1 ≦ 1.3 × L2 is established. L1 and L2 may be substantially equal.

As will be described later, when the welded portion 110 is formed by resistance welding, the distance between the welded portion 110 and the electrode 74 is closer on the outside of the cylinder head body 106 than on the center side, so that current tends to concentrate. It becomes easy to generate heat. Therefore, it is preferable to make L2 slightly smaller than L1 in order to generate heat more evenly in the entire cylinder head body 106 during resistance welding.

Further, in the convex portion 124, the angle formed by the radial direction of the opening peripheral edge portion 32 and the surface direction of the first surface 132 is set to γ, and the angle formed by the axial direction of the opening peripheral edge portion 32 and the surface direction of the second surface 134 is defined as γ. When it is set to δ, it is preferable that the relationship of 0 ° <γ = δ <45 ° is established.

Next, a joining method of forming the welded portion 110 from the welded portion forming structure 100 and joining the valve seat 102 and the cylinder head main body 106 will be described. In this joining method, first, as shown in FIG. 14, the valve seat 102 and the cylinder head main body 106 are set between a set of electrodes including an electrode 74 and an electrode (not shown). At this time, the second tapered portion 118 of the valve seat 102 and the tapered surface 126 of the opening peripheral edge portion 32 are brought to face each other at intervals, and the apex 136 of the convex portion 124 is brought into contact with the first tapered portion 116.

Next, resistance welding is started by driving a set of electrodes in directions close to each other and energizing the valve seat 102 and the cylinder head body 106 while applying a pressure welding load. As a result, the contact portion between the valve seat 102 and the cylinder head main body 106 generates heat based on the contact resistance, and the convex portion 124 begins to melt. When the valve seat 102 and the cylinder head body 106 are brought close to each other while discharging the molten convex portion 124 from between the first joint surface 120 and the second joint surface 122, the molten convex portion 124 is as shown in FIG. The portion 124 and the first tapered portion 116 of the first joint surface 120 come into surface contact with each other.

At this time, since the relationship between L1 and L2 is set as described above, the length L1a of the portion of the first surface 132 that remains without melting and the length L1a of the second surface 134 that remains without melting. It is possible to proceed with resistance welding while maintaining a substantially equal relationship with the length L2a of the portion. The length L1a is the length from the first starting point 128 of the remaining first surface 132 to the end on the center side in the cross section along the axial direction of the opening peripheral edge 32. The length L2a is the length from the second starting point 130 of the remaining second surface 134 to the end on one end side in the cross section along the axial direction of the opening peripheral edge 32.

In particular, in the cross section along the axial direction of the opening peripheral edge portion 32, the surface connecting the first starting point portion 128 of the first surface 132 and the second starting point portion 130 of the second surface 134 and the axial direction of the opening peripheral edge portion 32 are It is preferable that the angle formed by the valve seat 102 is substantially equal to the angle formed by the first tapered portion 116 of the valve seat 102 and the axial direction of the opening peripheral edge portion 32.

When substantially the entire convex portion 124 is melted, as shown in FIG. 16, the first joint surface 120 and the second joint surface 122 come into contact with each other to form the welded portion 110, and the second tapered portion 118 is formed. One end side of the first joint surface 120 and one end side of the tapered surface 126 of the tapered surface 126 of the second joint surface 122 come into contact with each other. At this time, the energization is stopped immediately before the one end side of the second tapered portion 118 with respect to the first joint surface 120 and the one end side with respect to the second joint surface 122 of the tapered surface 126 come into contact with each other, or at the same timing as the contact. Then, the resistance welding is finished.

Thereby, the valve seat 102 and the cylinder head main body 106 can be joined in a desired positional relationship. After that, the valve seat 102 is machined to form the valve contact surface 38 (see FIG. 4), whereby a cylinder head can be obtained. That is, in this cylinder head, the welded portion 110 is formed by the first joint surface 120 and the second joint surface 122. Further, one end side of the second tapered portion 118 with respect to the first joint surface 120 and one end side of the tapered surface 126 with respect to the second joint surface 122 are non-melting portions that only abut against each other.

Next, the effects of the welded portion forming structure 100 and the joining method according to the second embodiment will be described. In the welded portion forming structure 100 as well, as in the welded portion forming structure 10 according to the first embodiment, since the convex portion 124 is provided on the second joint surface 122 of the opening peripheral edge portion 32, the apex 136 of the convex portion 124 is provided. Can be started by resistance welding in a state where the first joint surface 120 is in line contact with the first joint surface 120. As a result, even if the shapes of the valve seat 102 and the cylinder head body 106 vary, it is possible to prevent the contact area between the valve seat 102 and the cylinder head body 106 at the time of contact from varying.

Further, in the welded portion forming structure 100, the shape of the convex portion 124 is set so that L1 and L2 are substantially equal, and resistance welding can proceed while maintaining a relationship in which L1a and L2a are substantially equal. As a result, it is possible to prevent the length (energization distance) of the current flowing through the convex portion 124 during resistance welding from fluctuating for each portion of the convex portion 124, so that the valve seat 102 and the cylinder head main body 106 (melted convex portion) can be prevented. It is possible to suppress the occurrence of a temperature difference in the contact surface with 124).

In particular, it is preferable that the electrode 74 is provided with the insulating portion 138 so as to go around the outer edge of the surface of the valve seat 102 facing the base end surface 50. The insulating portion 138 is composed of a gap or an insulating member provided in the electrode 74, and partially insulates the electrode 74 and the valve seat 102. By providing the insulating portion 138 on the electrode 74 in this way, it is possible to maintain a relationship in which the lengths of the current paths are equal over the entire energization time of resistance welding.

Therefore, according to the welded portion forming structure 100, the valve seat is from the start to the end of the resistance welding regardless of whether or not the shape of the valve seat 102 and the cylinder head body 106 varies. The contact surface between the 102 and the cylinder head body 106 can be heated substantially evenly. As a result, it is possible to suppress the variation in the bonding strength between the valve seat 102 and the cylinder head main body 106, and to maintain good bonding quality by the welded portion 110. In other words, it is possible to form a welded portion 110 capable of satisfactorily joining the valve seat 102 and the cylinder head body 106.

Further, in the welded portion forming structure 100 according to the second embodiment, the shape of the convex portion 124 is set so that the relationship of 0 ° <γ = δ <45 ° is established. In this case, it is possible to reduce the amount of the molten convex portion 124 discharged from between the first joint surface 120 and the second joint surface 122 during resistance welding. This makes it possible to reduce the energy required to form the weld 110. The convex portion 124 is not limited to being set in a shape in which the relationship of 0 ° <γ = δ <45 ° is established, and for example, the sizes of γ and δ may be different from each other. .. Further, each of γ and δ may be 0 ° or 45 ° or more.

The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

For example, with respect to the convex portions 58, 82, 84 of the welded portion forming structure 10 according to the first embodiment, 0 ° < The shape may have a relationship corresponding to γ = δ <45 °.

[Example 1]
As shown in FIG. 11A, the shape of the convex portion 82 was set so that α> β and β = 0. That is, in the convex portion 82, a relationship that satisfies all of α> 0, α ≧ β, and β ≧ 0 is established.

Further, the shape of the valve seat 78 was set so as to have a relationship of a = 5.00, b = 5.35, and c = 0.20. That is, in this valve seat 78, b / a = 1.07 and c = b / 26.75, and a relationship that satisfies all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 is established.

The welded portion 20 was formed between the first joint surface 34 and the second joint surface 36 by applying the above joining method to the convex portion 82 and the valve seat 78. At this time, a displacement amount measurement test was performed to determine the displacement amount of the valve seat 78 due to the pressure contact load. In addition, a joint strength measurement test was performed to determine the joint strength of the welded portion 20.

Specifically, the first joint surface 34 when load center points are generated at three locations, the outer and center sides in the radial direction of the surface to which the pressure contact load is applied from the electrode 74 of the valve seat 78, and the intermediate portion thereof. Was subjected to a displacement measurement test. For each of these load center points, the amount of displacement of the first joint surface 34 from the beginning when the apex 72 of the convex portion 82 and the first joint surface 34 were brought into contact with each other was defined as the amount of displacement of the valve seat 78. The results of the displacement amount measurement test at each of these locations are shown in FIG. 17A as Example 1.

Further, in the joint strength measurement test, the torque applied to the valve seat 78 is gradually increased with the cylinder head body 16 fixed, and the magnitude of the torque when the second joint surface 36 and the first joint surface 34 are separated from each other. Was calculated as the joint strength. The result of performing this joint strength measurement test three times is shown in FIG. 17B as Example 1.

[Example 2]
A displacement amount measurement test was performed in the same manner as in Example 1 except that the shape of the valve seat 78 was set to have a relationship of a = 5.00, b = 5.35, and c = 2.00. The results are shown in FIG. 17A as Example 2, and the results of the joint strength measurement test are shown in FIG. 17B as Example 2. Since the valve seat 78 has b / a = 1.07 and c = b / 2.67, b / a ≧ 1 is satisfied, but b / 3 ≧ c ≧ 0 is not satisfied.

From FIG. 17A, it can be seen that in the first embodiment, the displacement amount obtained by the displacement amount measurement test can be stably reduced in the entire radial direction of the valve seat 78 as compared with the second embodiment. Further, from FIG. 17B, it can be seen that in Example 1, the variation between the bonding strengths obtained by the three bonding strength measurement tests is small as compared with Example 2, and the bonding strength can be stably increased.

[Example 3]
The results of performing a displacement amount measurement test on the valve seat 78 and the convex portion 82 having the same shape as in the first embodiment are further shown in FIG. 18A as the third embodiment, and the joint strength is measured. The result of the test is shown in FIG. 18B as Example 3.

[Example 4]
A displacement amount measurement test was performed in the same manner as in Example 1 except that the shape of the valve seat 78 was set to have a relationship of a = 5.20, b = 3.97, and c = 0.20. The results are shown in FIG. 18A as Example 4, and the results of the joint strength measurement test are shown in FIG. 18B as Example 4. In this valve seat 78, since b / a = 0.76 and c = b / 19.85, b / 3 ≧ c ≧ 0 is satisfied, but b / a ≧ 1 is not satisfied.

From FIG. 18A, it can be seen that in the third embodiment, the displacement amount obtained by the displacement amount measurement test can be stably reduced in the entire radial direction of the valve seat 78 as compared with the fourth embodiment. Further, from FIG. 18B, it can be seen that in Example 3, the variation between the bonding strengths obtained by the three bonding strength measurement tests is small and the bonding strength can be increased as a whole as compared with Example 4.

From the above Examples 1 to 4, the valve seat 78 is deformed by the pressure welding load by forming the valve seat 78 into a shape that satisfies all of b / a ≧ 1 and b / 3 ≧ c ≧ 0. It can be seen that can be suppressed more effectively. As a result, resistance welding can be performed while the valve seat 78 and the cylinder head body 16 are in good contact with each other, so that the joining quality of the welded portion 20 can be improved.

[Example 5]
The shape of the convex portion 124 shown in FIG. 13 was set to L1 = 1.28 × L2, and L2 was set to be slightly smaller than L1 (L1 ≧ L2). The results of joint strength measurement tests performed on the convex portion 124 and the valve seat 102 shown in FIG. 12 in the same manner as in Example 1 are shown in FIG. 19 as Example 5.

[Example 6]
The shape of the convex portion 124 was set to L1 = (0.738 to 0.952) × L2, and L2 was set to be slightly larger than L1 (L1 <L2). The results of joint strength measurement tests performed on the convex portion 124 and the valve seat 102 shown in FIG. 12 in the same manner as in Example 1 are shown in FIG. 19 as Example 6.

From FIG. 19, it can be seen that good bonding strength can be obtained in both Example 5 and Example 6. Further, in Example 5, it can be seen that the variation between the joint strengths obtained by the three joint strength measurement tests is smaller than that in Example 6, and the joint strength can be increased more stably. Therefore, in the convex portion 124, the contact surface between the valve seat 102 and the cylinder head main body 106 is made slightly smaller than L1 within the range of 0.7 × L2 ≦ L1 ≦ 1.3 × L2. Resistance welding can be performed while heating more evenly, and the joining quality of the welded portion 20 can be further effectively improved.

10, 100 ... Welded portion forming structure 12, 78, 102 ... Valve seat 14, 104 ... First metal member 16, 106 ... Cylinder head main body 18, 108 ... Second metal member 20, 110 ... Welded portion 22 ... Cylinder head 24 ... Insertion port 28 ... Intake port 30 ... Exhaust port 32 ... Opening peripheral edges 33, 114 ... Outer peripheral surfaces 34, 120 ... First joint surface 36, 122 ... Second joint surface 48 ... Inner peripheral surface 50 ... Base end surface 52, 54 , 56, 76 ... Ends 58, 82, 84, 124 ... Convex 60 ... First tapered surface 62 ... Second tapered surface 64, 128 ... First starting point 66, 130 ... Second starting point 68, 132 ... Second 1st surface 70, 134 ... 2nd surface 72, 136 ... Apex 116 ... 1st tapered portion 118 ... 2nd tapered portion Z ... Intersection

Claims (8)

It is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted.
The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the base end in the insertion direction into the insertion port. A tapered first joint surface that expands in diameter toward the side is provided.
On the inner peripheral surface of the insertion port, an annular convex portion protruding from the second joint surface capable of forming a welded portion with the first joint surface, and one end side on which the convex portion of the second joint surface rises. The tapered first tapered surface extending in the direction of expanding the diameter of the insertion port from the first starting point of the insertion port toward the one end side of the insertion port, and the other that the convex portion of the second joint surface rises. A tapered second tapered surface extending from the second starting point on the end side toward the other end side of the insertion port in the direction of reducing the diameter of the insertion port is provided.
The convex portion extends from the first starting point portion toward the radial center side of the insertion port and from the second starting point portion toward the extending end portion of the first surface. It has the first surface and the second surface forming a corner portion.
When the radial distance between the apex of the corner portion and the first starting point portion is A and the radial distance between the apex and the second starting point portion is B, A> 0, A ≧ B. , A relationship that satisfies all of B ≧ 0 is established,
Moreover, the angle formed by the first joint surface with the axial direction of the first metal member and the second joint surface connecting the first starting point portion and the second starting point portion with the shortest distance form the axial direction of the insertion port. A welded portion forming structure characterized in that the angles are equal to each other. It is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted.
The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the base end in the insertion direction into the insertion port. A tapered first joint surface that expands toward the side is provided.
On the inner peripheral surface of the insertion port, an annular convex portion protruding from the second joint surface capable of forming a welded portion with the first joint surface, and one end side on which the convex portion of the second joint surface rises. The tapered first tapered surface extending in the direction of expanding the diameter of the insertion port from the first starting point of the insertion port toward the one end side of the insertion port, and the other that the convex portion of the second joint surface rises. A tapered second tapered surface extending from the second starting point on the end side toward the other end side of the insertion port in the direction of reducing the diameter of the insertion port is provided.
The convex portion extends from the first starting point portion toward the radial center side of the insertion port and from the second starting point portion toward the extending end portion of the first surface. It has the first surface and the second surface forming a corner portion.
On the internal angle side of the corner portion, the angle formed by the reference line and the first surface along the axial direction of the insertion port through the apex of the corner portion is defined as α, and the reference line and the second surface form. When the angle is β, a relationship that satisfies all of α> 0, α ≧ β, and β ≧ 0 is established.
Moreover, the angle formed by the first joint surface with the axial direction of the first metal member and the second joint surface connecting the first starting point portion and the second starting point portion with the shortest distance form the axial direction of the insertion port. A welded portion forming structure characterized in that the angles are equal to each other. It is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted.
The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the base end in the insertion direction into the insertion port. A first joint surface having a tapered portion that expands in diameter toward the side is provided.
An annular convex portion protruding from the second joint surface capable of forming a welded portion with the first joint surface is provided on the inner peripheral surface of the insertion port.
The convex portion includes a first surface extending from a first starting point portion on one end side on which the convex portion of the second joint surface rises toward the center side in the radial direction of the insertion port, and the second joint surface. It has a second surface extending from a second starting point portion on the other end side on which the convex portion rises toward the extending end portion of the first surface and forming a corner portion with the first surface. ,
The length from the first starting point portion of the first surface to the apex of the corner portion in the cross section along the axis of the insertion port is L1, and the length from the second starting point portion of the second surface to the apex. when to the L2, Chi elevational become the relationship 0.7 × L2 ≦ L1 ≦ 1.3 × L2,
When the angle formed by the radial direction of the insertion port and the surface direction of the first surface is γ, and the angle formed by the axial direction of the insertion port and the surface direction of the second surface is δ, 0 ° <γ = [delta] welds forming structure characterized in that one elevation relationship is made of <45 °. It is a welded portion forming structure for forming a welded portion for joining an annular first metal member and a second metal member having an insertion port into which the first metal member is inserted.
The first metal member is inserted from one end side to the other end side in the axial direction of the insertion port, and is inserted into the outer peripheral surface of the first metal member from the tip end side to the base end in the insertion direction into the insertion port. A first joint surface having a tapered portion that expands in diameter toward the side is provided.
An annular convex portion protruding from the second joint surface capable of forming a welded portion with the first joint surface is provided on the inner peripheral surface of the insertion port.
The convex portion includes a first surface extending from a first starting point portion on one end side on which the convex portion of the second joint surface rises toward the center side in the radial direction of the insertion port, and the second joint surface. It has a second surface extending from a second starting point portion on the other end side on which the convex portion rises toward the extending end portion of the first surface and forming a corner portion with the first surface. ,
The length from the first starting point portion of the first surface to the apex of the corner portion in the cross section along the axis of the insertion port is L1, and the length from the second starting point portion of the second surface to the apex. When is L2, the relationship of 0.7 × L2 ≦ L1 ≦ 1.3 × L2 is established.
The direction in which the inner peripheral surface of the first metal member extends along the axial direction of the first metal member and the base end surface which is the end surface of the first metal member on the base end side are the first metal member. The direction extending along the radial direction intersects at the intersection,
The end portion of the inner peripheral surface of the first metal member on the base end side coincides with the intersection, or is separated from the intersection toward the tip end side of the first metal member.
The end of the base end surface on the radial center side of the first metal member coincides with the intersection or is separated from the intersection to the outside of the first metal member in the radial direction.
Let a be the distance between the tip end side of the inner peripheral surface of the first metal member and the intersection, and the radial outer end of the first metal member and the intersection of the base end surface. B / a ≧ 1, b / 3 ≧ c ≧, where b is the distance between A welded portion forming structure characterized in that a relationship satisfying all of 0 is established. The welded portion forming structure according to claim 3 or 4 , wherein the L1 and the L2 are substantially equal to each other. In the welded portion forming structure according to any one of claims 1 to 5,
A welded portion forming structure characterized in that the first metal member is made of an iron-based material and the second metal member is made of an aluminum-based material. In the welded portion forming structure according to any one of claims 1 to 6,
The first metal member is a valve seat.
The second metal member is a cylinder head body.
A welded portion forming structure characterized in that the insertion port is an opening peripheral edge portion of a port provided in the cylinder head main body. A method for joining a metal member, which forms the welded portion from the welded portion forming structure according to any one of claims 1 to 7 and joins the first metal member and the second metal member.
A step of bringing the apex of the corner portion into contact with the first joint surface,
By energizing the first metal member and the second metal member while applying a pressure contact load, the melted convex portion is discharged from between the first joint surface and the second joint surface, and the first A step of bringing the metal member close to the second metal member and bringing the first joint surface into contact with the second joint surface.
A method for joining a metal member.

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