JP2019048334A - Weld part formation structure and method of joining metal member - Google Patents

Abstract

To provide a weld part formation structure and a method of joining metal members capable of excellently joining a first metal member and a second metal member.SOLUTION: A weld part forming structure 10 forms a weld part 20 for joining a valve seat 12 and a cylinder head main body 16. A protruded part 58 which protrudes from a second joint surface 36, a first tapered surface 60 extended from a first starting part 64 and a second tapered surface 62 extended from a second starting part 66 are provided on an inner circumferential surface of an opening peripheral part 32. When a radial distance between an apex 72 of a corner part formed by a first surface 68 of the protruded part 58 and a second surface 70 and the first starting part 64 is set as A and a radial distance between the apex 72 and the second starting part 66 is set as B, a relation which satisfies all of A>0, A≥B, B≥0 holds. Further, an angle θ1 of the first joint surface 34 of the valve seat 12 to an axial direction is equal to an angle θ2 of the second joint surface 36 to the axial direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welded portion forming structure for forming a welded portion joining a first metal member and a second metal member, and a welded portion is formed from the welded portion forming structure to form a first metal member and a second metal member. And a method of joining metal members.

  For example, Patent Document 1 discloses the first metal member and the second metal by resistance welding regardless of methods such as press-fitting with a low degree of freedom in shape design, usable materials are limited, and laser cladding has low manufacturing efficiency. It is disclosed to form a weld with a member. Specifically, the annular first metal member is inserted into the insertion opening provided in the second metal member, and the first bonding surface of the first metal member and the second bonding surface of the second metal member are pressure-welded It energizes 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 first metal member and the second metal member may have variations in shape within at least the range of processing tolerance. If the contact area when the first bonding surface and the second bonding surface abut against each other for each of the first metal member and the second metal member due to the influence of the variation of the shape, etc., the heat generation amount based on the contact resistance There are also variations. As a result, there is a concern that the bonding strength between the first metal member and the second metal member may vary, and it may be difficult to maintain good bonding quality by the welded portion.

  Therefore, Patent Document 1 proposes that an annular convex portion be provided on the second bonding surface, and the apex of the convex portion be in line contact with the first bonding surface. Even if the variation in the shape described above occurs, the contact area between the apex of the line-contacting convex portion and the first bonding surface can be easily maintained constant, so the variation in heat generation based on the contact resistance It is said that what happens is suppressed.

Japanese Patent Application Laid-Open No. 09-79012

  The convex portion and the first joint surface are in line contact at the beginning of contact, but when resistance welding proceeds and the convex portion melts, the convex surface becomes a surface contact between the melting surface of the convex portion and the first joint surface. Furthermore, 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 are in contact with each other, and the welded portion Is formed.

  As described above, the contact area or the like between the convex portion and the first joint surface changes in accordance with the progress of the resistance welding. For this reason, only by providing the convex portion on the second joint surface, the first metal member and the second metal member are maintained in good contact with each other from the start to the end of the resistance welding. In some cases, the entire contact surface can not be heated uniformly. As a result, it is not possible to eliminate the concern that the bonding strength between the first metal member and the second metal member may vary, and it is still difficult to maintain good bonding quality by the welded portion.

  The present invention has been made to solve the above-described problems, and provides a weld portion forming structure and a method of joining metal members capable of forming a weld portion capable of joining the first metal member and the second metal member well. provide.

  In order to achieve the above object, the present invention provides a weld for forming a weld that joins an annular first metal member and a second metal member having an insertion opening 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 the outer peripheral surface of the first metal member is inserted into the insertion port. Second joint which can form a welded portion with the first joint surface on the inner peripheral surface of the insertion opening, the first joint surface having a tapered shape expanding in diameter from the distal end side to the proximal end side in the second direction In a direction in which the diameter of the insertion opening is expanded from the first starting point portion on the one end side where the convex portion of the second joint surface rises and the annular convex portion protruding from the surface and the one end side of the insertion opening A second tapered surface on which the projecting portion of the second bonding surface rises, and a second tapered surface on which the convex portion of the second bonding surface rises. A tapered second tapered surface is provided extending in the direction of reducing the diameter of the insertion opening from the point portion toward the other end side of the insertion opening, and the convex portion is formed from the first starting point portion. A first surface extending toward the radial center of the insertion slot, and an extension end portion of the first surface from the second starting point portion to form a corner portion with the first surface A distance between the apex of the corner and the first starting point in the radial direction is A, and the distance between the apex and the second starting point in the radial direction is B and At that time, a relationship satisfying all of A> 0, A ≧ B, B ≧ 0 holds, and an angle between the first joint surface and the axial direction of the first metal member, the first starting point portion, and the first start point It is characterized in that an angle formed between the second joint surface connecting the second starting point portions by the shortest distance and the axial direction of the insertion port is equal.

  In this welded portion forming structure, since the convex portion is provided on the second joint surface of the second metal member, the first metal member and the first metal member are not in contact with the apex of the convex portion on the first joint surface. (2) It is possible to start resistance welding by conducting electricity while applying pressure load to the metal member. For this reason, even when the first metal member and the second metal member have a variation in shape, it is possible to suppress variation in the contact area between the first metal member and the second metal member at the beginning of the contact.

  Further, in the welded portion forming structure, the shape of the convex portion is set so as to satisfy the above relationship, and the angle formed by the first joint surface with the axial direction of the first metal member and the second joint surface It is set so that the angle of the axis direction of and and the angle to make become equal. As a result, even if the resistance welding proceeds while melting the convex portion, the first metal member and the second metal in the radial direction of the insertion port before the first bonding surface and the second bonding surface come into contact with each other. It can be avoided that the center of the contact surface with the member moves from the initial contact position of the top of the convex portion and the first joint surface to the radial center side. For this reason, it can suppress that a deformation | transformation arises in a 1st metal member by the press-contact load at the time of resistance welding.

  Therefore, according to this welded portion forming structure, regardless of whether the first metal member and the second metal member have variations in shape or the like, the first time from the start to the end of the resistance welding can be obtained. The metal member and the second metal member can be well in contact with each other. This can suppress variation in the bonding strength between the first metal member and the second metal member, so that the bonding quality by the welded portion can be maintained well. In other words, it is possible to form a weld that can satisfactorily bond 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 the outer peripheral surface of the first metal member is proximal to the distal end side in the insertion direction to the insertion port A tapered first joint surface expanding in diameter toward the end, and an annular convex projecting from a second joint surface capable of forming a welded portion with the first joint surface on the inner peripheral surface of the insertion port A tapered first portion extending in a direction in which the diameter of the insertion port is increased from the first starting point portion on the one end side where the convex portion of the second joint surface rises up to the one end side of the insertion port The taper surface and the second starting point on the other end side where the convex portion of the second bonding surface rises up A tapered second tapered surface is provided extending in the direction of reducing the diameter of the insertion opening toward the end side, and the convex portion is provided on the radial center of the insertion opening from the first starting point portion. And a second surface extending from the second starting point toward the extending end of the first surface to form the first surface and the corner portion. The angle between the first surface and the reference line along the axial direction of the insertion opening through the apex of the corner on the inner angle side of the corner is α, and the reference line and the second surface are When an angle formed is β, a relationship satisfying all of α> 0, α ≧ β, β ≧ 0 holds, and an angle between the first bonding surface and the axial direction of the first metal member, and It is characterized in that an angle formed between the first bonding portion and the second bonding surface connecting the second starting portion at the shortest distance is equal to an axial direction of the insertion port.

  Also in this welded portion forming structure, regardless of whether the first metal member and the second metal member have a variation in shape or the like, the resistance welding is started to the first metal member from the start to the end. Good contact with the second metal member can be achieved. As a result, it is possible to form a welded portion capable of joining the first metal member and the second metal member well.

  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 the outer peripheral surface of the first metal member is proximal to the distal end side in the insertion direction to the insertion port A first joint surface having a tapered portion expanding in diameter toward the end, and a circle protruding from a second joint surface capable of forming a weld with the first joint surface is provided on the inner peripheral surface of the insertion port An annular convex portion is provided, and the convex portion extends from a first starting point on the one end side on the one end side where the convex portion of the second joint surface rises up to a center side in a radial direction of the insertion port. Surface and the second starting point on the other end side where the convex portion of the second bonding surface rises up to the extending end of the first surface From the first starting point portion of the first surface to the apex of the corner in a cross section along the axis of the insertion port, having a second surface that extends to form the first surface and the corner; And the length from the second starting point portion of the second surface to the vertex is L2, a relationship of 0.7 × L2 ≦ L1 ≦ 1.3 × L2 is satisfied. I assume.

  In this welded portion forming structure, even if the first metal member and the second metal member have a variation in shape due to the convex portion being provided on the second bonding surface of the second metal member, It can suppress that the contact area of the 1st metallic member and the 2nd metallic member of the beginning of contact varies.

  Further, in this welded portion forming structure, by setting the shape of the convex portion as described above, even if the resistance welding is advanced while melting the convex portion, the length of the current path (energization distance) is convex It is possible to suppress variation in each part of the department. For this reason, it can suppress that a temperature difference arises in the contact surface of a 1st metallic member and a 2nd metallic member at the time of resistance welding.

  Therefore, according to this welded portion forming structure, regardless of whether the first metal member and the second metal member have variations in shape or the like, the first time from the start to the end of the resistance welding can be obtained. The contact surface between the metal member and the second metal member can be heated substantially uniformly. As a result, it is possible to suppress 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 weld that can satisfactorily bond the first metal member and the second metal member.

  In the welded portion forming structure described above, 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 configuration.

  In the welded portion forming structure described above, an angle between the radial direction of the insertion opening and the surface direction of the first surface is γ, and an angle between the axial direction of the insertion opening and the surface direction of the second surface is δ It is preferable that the relation of 0 ° <γ = δ <45 ° is satisfied. In this case, at the time of resistance welding, the amount of the molten convex portion discharged from between the first joint surface and the second joint surface can be reduced. This makes it possible to reduce the energy required to form the weld.

  In the welded portion forming structure described above, a base in which the inner peripheral surface of the first metal member extends in the axial direction of the first metal member and the end face of the first metal member on the proximal end side The end face intersects with the direction in which the first metal member extends in the radial direction at the intersection, and the proximal end of the inner circumferential surface of the first metal member coincides with the intersection Or the end portion of the base end surface of the base end surface, which is separated from the intersection portion toward the tip end side of the first metal member, coincides with the intersection portion at the radial center of the first metal member, or The distance between the end portion on the tip end side of the inner peripheral surface of the first metal member and the intersection portion is a, and the distance from the intersection portion to the outside in the radial direction of the first metal member is The distance between the radial outer end portion of the first metal member and the intersection portion is b, and the radial direction of the first metal member of the base end surface When the distance between the end of the central side and the intersection is c, it is preferable that the relationship that satisfies all of the b / a ≧ 1, b / 3 ≧ c ≧ 0 holds.

  In this case, since the rigidity of the first metal member with respect to the pressure load can be favorably improved, it is possible to more effectively suppress the deformation of the first metal member at the time of 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 the joint quality by the welded portion can be further enhanced.

  In the welded portion forming structure, it is preferable that the first metal member be made of an iron-based material, and the second metal member be made of an aluminum-based material. For example, in the structure in which the first metal member is accumulated on the second bonding surface to form a weld by the laser cladding method, restrictions on materials applicable as the first metal member and the second metal member are large. However, in the welded part 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 Even if the second metal member is made of an aluminum-based material, the welded portion can be favorably formed. The use of an iron-based material makes it possible to improve the wear resistance of the first metal member, and the use of an aluminum-based material makes it possible to reduce the weight of the second metal member.

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

  Furthermore, the present invention is a method of joining metal members, wherein the weld portion is formed from the above-described weld portion forming structure, and the first metal member and the second metal member are joined, And a step of bringing the apexes of the corner portions into contact with each other, and applying a pressing load to the first metal member and the second metal member while applying a pressure load to the molten convex portion, the first joint surface and the first joint surface. Bringing the first metal member and the second metal member into proximity with each other while discharging from between the two bonding surfaces, and bringing the first bonding surface into contact with the second bonding surface. I assume.

  According to this method of bonding metal members, the first metal member and the second metal member can be well brought into contact with each other regardless of whether or not the first metal member and the second metal member have variations in shape or the like. By heating, it is possible to form a weld excellent in joint quality. As a result, the first metal member and the second metal member can be joined well to obtain a joined body.

  According to the welding portion forming structure and the method of joining metal members of the present invention, it is possible to form a welded portion capable of joining the first metal member and the second metal member well and obtain a joined body excellent in joining strength. .

It is sectional drawing of the valve seat (1st metal member) and cylinder head main body (2nd metal member) of the welding part formation structure which concern on 1st Embodiment of this invention. It is a principal part enlarged view of the valve seat of FIG. It is a principal part enlarged view of the cylinder head main body of FIG. It is a principal part schematic sectional drawing of the cylinder head obtained by applying the welding part formation structure of FIG. It is explanatory drawing explaining a mode that the 1st joint surface of the valve seat of FIG. 2 and the convex part provided in the 2nd joint surface of the cylinder head main body of FIG. 3 were contact | abutted. It is explanatory drawing explaining a mode that the valve seat and the cylinder head main body were made to approach by fuse | melting the convex part of FIG. It is explanatory drawing explaining a mode that the valve seat and cylinder head main body of FIG. 6 were made to adjoin more, and the welding part which joins a 1st joint surface and a 2nd joint surface was 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 by relationship with the valve seat before a welding part 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 1st joint surface by pressure load. It is a principal part enlarged view of the valve seat concerning the modification of a 1st embodiment. FIG. 11A is an enlarged view of a main part of a cylinder head main body according to a modification of the first embodiment, and FIG. 11B is an enlarged view of a main part of a cylinder head main body according to another modification. It is sectional drawing of the valve seat of the welding part formation structure which concerns on 2nd Embodiment of this invention, and a cylinder head main body. It is a principal part enlarged view of the cylinder head main body of FIG. It is explanatory drawing explaining a mode that the convex part provided in the 2nd joint surface of a cylinder head main body was contact | abutted to the 1st joint surface of the valve seat of FIG. It is explanatory drawing explaining a mode that the valve seat and the cylinder head main body were made to approach by fuse | melting the convex part of FIG. It is explanatory drawing explaining a mode that the valve seat and cylinder head main body of FIG. 15 were made to further approach, and the welding part which joins a 1st joint surface and a 2nd joint surface was formed. FIG. 17A is a graph showing the results of displacement amount measurement tests of Examples 1 and 2, and FIG. 17B is a graph showing the results of bonding strength measurement tests of Examples 1 and 2. FIG. 18A is a graph showing the results of displacement amount measurement tests of Examples 3 and 4, and FIG. 18B is a graph showing the results of bonding 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.

  The preferred embodiments of the welded portion forming structure and the method for joining metal members according to the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, components having the same or similar functions and effects may be denoted 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 the first metal member 14 which is the valve seat 12 and the second metal member 18 which is the cylinder head main body 16. An example will be described which is for forming a weld 20 (see FIG. 4) for joining together. That is, the welding portion 20 is formed from the welding portion forming structure 10 by the method of joining metal members according to the first embodiment (hereinafter, also simply referred to as joining method), and the valve seat 12 and the cylinder head main body 16 are joined. Thus, 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 weld 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, the material being capable of resistance welding. The weld forming structure 10 can be applied in the same manner as the cylinder head body 16.

  First, with reference to FIG. 4, the cylinder head 22 having the valve seat 12 and the cylinder head main body 16 after forming the welding portion 20 will be described. 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, pure aluminum or an aluminum-based material such as an aluminum alloy. The cylinder head body 16 is provided with an intake port 28 and an exhaust port 30 (hereinafter collectively referred to as a port), one end of which opens toward the combustion chamber 26. The opening peripheral edge portion 32 of these ports is the insertion port 24, and the valve seat 12 is joined to the cylinder head main body 16 via the welding 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 portion 32 form the weld portion 20. .

  Each of the ports can be opened and closed by the valve 40 being seated or separated 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 cool the valve 40 etc. well.

  Next, with reference to FIGS. 1 to 3, a weld portion forming structure 10 for forming the above-described weld portion 20 will be described. That is, the valve seat 12 and the cylinder head main body 16 before forming the welding portion 20 will be described. The opening peripheral edge portion 32 and the valve seat 12 shown in FIG. 1 are arranged such 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 (the arrow X1 side, hereinafter also simply referred to as one end side) in the axial direction of the opening peripheral portion 32 toward the other end side (the arrow X2 side; hereinafter simply referred to as the other end side) Be done.

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

  As shown in FIGS. 1 and 2, the distal end surface 44 of the valve seat 12 is tapered so as to increase in diameter from the distal end side to the proximal end side. The outer circumferential surface 33 of the valve seat 12 is provided with a tapered first joint surface 34 whose diameter increases from the distal end side to the proximal end side. The inner circumferential surface 48 of the valve seat 12 extends in the axial direction, and the proximal end surface 50 of the valve seat 12 extends in the radial direction of the valve seat 12.

  As shown in FIG. 2, the extending direction of the inner circumferential surface 48 of the valve seat 12 intersects with the extending direction of the base end surface 50 of the valve seat 12 at the intersection Z. In the present embodiment, the intersection Z coincides with both the proximal end 52 of the inner circumferential 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 56 on the tip end side of the inner circumferential surface 48 and the intersection Z is a, and the distance between the end 56 on the outside of the base end surface 50 and the intersection Z is b. Assuming that the distance between the end 54 on the center side of the center and the intersection Z is c (see FIG. 10), a relationship satisfying all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 holds. In the present embodiment, as described above, c = 0 because the end 54 on the center side of the proximal surface 50 and the intersection Z coincide with each other.

  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 portion 32. The convex portion 58 annularly protrudes from the second joint surface 36 capable of forming the first joint surface 34 of the valve seat 12 and the weld portion 20 (see FIG. 4) as described above. The first tapered surface 60 has a tapered shape extending in a direction in which the diameter of the opening peripheral portion 32 is increased from the first starting point portion 64 on one end side where the convex portion 58 of the second bonding surface 36 rises up to one end side in the axial direction. It is. The second tapered surface 62 extends in the direction of reducing the diameter of the opening peripheral portion 32 from the second starting point portion 66 on the other end side where the convex portion 58 of the second bonding surface 36 rises up to 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 of the opening peripheral portion 32, and a second surface 68 from the second starting point portion 66. And a second surface 70 extending towards the extended end of the first surface 68 and forming a corner. Assuming that 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, A0B, B The relationship satisfying all ≧ 0 holds. Further, on the inner corner side of the corner, the angle between the first surface 68 and the reference line L along the axial direction of the opening peripheral portion 32 through the apex 72 is defined as α, and the reference line L and the second surface 70 are formed. When an angle is β, a relationship satisfying all of α> 0, α ≧ β, and β ≧ 0 holds.

  As shown in FIG. 1, the angle between the first joint surface 34 and the axial direction of the valve seat 12 is θ1 with respect to the valve seat 12 and the opening peripheral portion 32, and the first starting point 64 and the second starting point 66 are the shortest distance. When an angle formed by the connecting second bonding surface 36 and the axial direction of the opening peripheral portion 32 is θ2, θ1 and θ2 are set to be equal. Here, the setting of equalizing θ1 and θ2 includes the case where θ1 and θ2 are approximately equal.

  When the distal end surface 44 and the second tapered surface 62 abut each other by making the taper angles of the distal end surface 44 of the valve seat 12 and the second tapered surface 62 of the opening peripheral portion 32 substantially equal to each other, the valve Each shape is set so that the seat 12 and the cylinder head main body 16 have a desired joining positional relationship.

  Next, with reference to FIG. 5 to FIG. 8 together, a joining method will be described in which the valve seat 12 and the cylinder head main body 16 are joined by forming the weld portion 20 from the weld portion forming structure 10 described above.

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

  One set of electrodes is connected to a power supply via, for example, a capacitor, and can be driven in directions toward or away from each other by a drive mechanism (not shown) such as a pressure cylinder. Therefore, by driving the pair of electrodes in the direction in which they approach each other, it is possible to apply a pressing force (pressure contact load) in the direction in which the valve seat 12 and the cylinder head body 16 approach each other. Thus, resistance welding can be started by energizing the valve seat 12 and the cylinder head main body 16 while applying a pressure contact load.

  That is, the contact portion between the valve seat 12 and the cylinder head main body 16 generates heat based on the contact resistance. Accordingly, when the melting point of the cylinder head main body 16 (convex portion 58) is reached, the convex portion 58 starts 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 melted convex portion 58 from between the first joint surface 34 and the second joint surface 36. it can. At this time, the molten convex portion 58 and the first bonding surface 34 are in 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 disposed radially outward of the contact position P1 at the time of initial contact.

  As shown in FIG. 7, when substantially the entire protrusion 58 is melted, the first joint surface 34 and the second joint surface 36 are in contact with each other to form the welded portion 20, and the tip surface 44 and the second tapered surface 62 abuts. The contact surface center P3 between the valve seat 12 and the cylinder head main body 16 at this time is disposed closer to the center in the radial direction than the contact surface center P2.

  That is, even if the resistance welding is advanced while melting the convex portion 58, as shown in the explanatory view of FIG. 8, the contact surface center is in the period before the first bonding surface 34 and the second bonding surface 36 contact. It is avoided that P2 moves to the radial center side with respect to the contact position P1.

  Further, when the front end surface 44 and the second tapered surface 62 abut on each other, the valve seat 12 and the cylinder head main body 16 are compared to the case where only the first joint surface 34 and the convex portion 58 until then. Contact area increases rapidly. Therefore, the current value per unit area flowing between the valve seat 12 and the cylinder head main body 16 is reduced (contact resistance is reduced). By this, the calorific value of the contact surface of the valve seat 12 and the cylinder head main body 16 is reduced. As a result, the amount of heat necessary to melt the cylinder head body 16 can not be obtained, and the melting of the cylinder head body 16 temporarily stops.

  Therefore, the cylinder head main body 16 is further melted by stopping the energization immediately before or at the same time the contact between the tip end surface 44 and the second tapered surface 62, in other words, the second tapered surface 62 Can be avoided from melting. Thereby, the resistance welding can be finished in a state where the tip end surface 44 and the second tapered surface 62 are in contact with each other.

  As described above, the tip end surface 44 and the second tapered surface 62 have their shapes set such that the valve seat 12 and the cylinder head main body 16 have a desired positional relationship when they abut each other. For this reason, by forming the welding portion 20 as described above, the valve seat 12 and the cylinder head main body 16 can be joined in a desired positional relationship. Thereafter, 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 the cylinder head 22, the welded portion 20 is formed by the first joint surface 34 and the second joint surface 36, and the non-melted portion only abuts on the tip end surface 44 and the second tapered surface 62. It becomes.

  Next, the effect of the welding part formation structure 10 which concerns on 1st Embodiment, and a joining method is demonstrated. In the weld forming structure 10, as described above, since the convex portion 58 is provided on the second joint surface 36 of the opening peripheral portion 32, a state where the apex 72 of the convex portion 58 is in line contact with the first joint surface 34 You can start resistance welding. As a result, even when the valve seat 12 and the cylinder head main body 16 have a variation in shape, it is possible to suppress variation in the contact area between the valve seat 12 and the cylinder head main body 16 at the beginning of contact.

  Further, in the weld portion forming structure 10, the relationship is satisfied such that a relationship satisfying all of A> 0, A ≧ B, B ≧ 0, or a relationship satisfying all of α> 0, α ≧ β, and β 成 り 立 つ 0 holds. 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 become equal. Thus, as described above, even if the resistance welding proceeds while melting the convex portion 58, the contact surface center P2 is the contact position before the first bonding surface 34 and the second bonding surface 36 contact. It is possible to avoid moving closer to the radial center than P1. As a result, it is possible to effectively suppress the deformation of the valve seat 12 due to the pressure contact load at the time of resistance welding.

  This is also apparent 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 indicates the amount of displacement in the radial direction of the end portion 76 (see FIGS. 2 and 5 and the like) of the base end side of the first bonding surface 34 with respect to the reference position. The reference position is the radial position (see FIG. 5) of the end 76 at the beginning when the first joint surface 34 and the apex 72 abut. That is, the amount of deformation of the first joint surface 34 of the valve seat 12 due to the pressure load can be known from the value shown on the vertical axis.

  From FIG. 9, as the contact surface center P2 moves toward the radial center, the end 76 of the first joint surface 34 is largely displaced outward in the radial direction, that is, the proximal end of the valve seat 12 is in the radial direction. It can be seen that it bends to the outside of the On the other hand, when the contact surface center P2 moves to the outer side in the radial direction, the amount of displacement of the end 76 of the first joint surface 34 to the radial center side moves the contact surface center P2 to the central side in the radial direction Is much smaller than the displacement of the end 76 in the case of FIG. That is, it is understood that the deformation of the valve seat 12 can be suppressed by avoiding the movement of the contact surface center P2 to the radial center side.

  Further, in the welded portion forming structure 10, the shape of the valve seat 12 is set such that the relationship satisfying all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 holds. Thereby, the rigidity of the valve seat 12 with respect to the pressure contact load can be favorably improved, so that deformation of the valve seat 12 at the time of 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 main body 16 vary, the valve seat 12 and the cylinder head main body 16 can be favorably made between the start and the end of resistance welding. It can be in contact. As a result, it is possible to suppress variations in the joint strength between the valve seat 12 and the cylinder head main body 16, and therefore, it is possible to maintain good joint quality by the welded portion 20. As a result, it is possible to form a welded portion 20 excellent in bonding strength.

  By the way, for example, in the structure which builds up the valve seat 12 on the 2nd joint surface 36, and forms the welding part 20 by the laser cladding method, restrictions of the material applicable as the valve seat 12 and the cylinder head main body 16 are large. However, in the weld forming structure 10, various materials capable of resistance welding can be used as the valve seat 12 and the cylinder head body 16. Therefore, as described above, even when the valve seat 12 is made of an iron-based material and the cylinder head main body 16 is made of an aluminum-based material, the welded portion 20 can be formed well. The use of an iron-based material makes it possible to improve the wear resistance of the valve seat 12 and the like, and the use of an aluminum-based material makes it possible to reduce the weight of the cylinder head body 16 and the like.

  In the weld forming structure 10, it is possible to form the weld 20 by resistance welding and join the first joint surface 34 of the valve seat 12 and the second joint surface 36 of the cylinder head main body 16. For this reason, 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 with a small fixed space. That is, as the thickness of the valve seat 12 can be reduced, the degree of freedom of the port shape 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. And so on can be enhanced (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 in a range where θ1 becomes equal to θ2 (see FIG. 1). It is possible. For example, as in a valve seat 78 shown in FIG. 10, a notch 80 may be provided on the proximal end side of the inner circumferential surface 48 and on the center side of the proximal end surface 50. In this valve seat 78, unlike the valve seat 12 described above, the end 52 on the base end side of the inner circumferential surface 48 is separated from the intersection Z toward the tip end, and the end 54 on the center side of the base end surface 50 is an intersection In order to separate from Z to the outside, c> 0. Also in this case, it is preferable that a relationship satisfying all of b / a ≧ 1 and b / 3 ≧ c> 0 holds. By this, similarly to the above-mentioned valve seat 12, since the rigidity of the valve seat 78 against the pressure load can be favorably improved, it is possible to more effectively suppress the deformation of the valve seat 78 at the time of resistance welding. Become.

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

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

  Next, a welded portion forming structure 100 according to the second embodiment will be described with reference to FIGS. 12 to 16. As in the first embodiment, also in the second embodiment, the weld forming structure 100 welds the first metal member 104 which is the valve seat 102 and the second metal member 108 which is the cylinder head body 106. Although the example which is for forming the part 110 (refer FIG. 16) is demonstrated, it is not limited in particular in these.

  That is, also by the joining method according to the second embodiment, the weld portion 110 is formed from the weld portion forming structure 100, and the valve seat 102 and the cylinder head main body 106 are joined to obtain the cylinder head (not shown). This cylinder head is replaced with the valve seat 12 shown in FIG. 1 and FIG. 7 etc., the cylinder head main body 16 and the welded portion 20, and the valve seat 102 shown in FIG. The configuration is the same as that of the above-described cylinder head 22 except for the provision of 110, so the detailed description thereof will be omitted.

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

  The surface direction of the tip end 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 which are different from each other in the surface direction. Each of the first tapered portion 116 and the second tapered portion 118 has a tapered shape that increases in diameter from the distal end side to the proximal end side. The first tapered portion 116 is disposed on the distal end side of the second tapered portion 118, and the base end of the first tapered portion 116 and the tip 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 outer end 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 And the first bonding surface 120.

  The shape of the outer peripheral surface 114 of the valve seat 102 is not limited to the above. A single tapered portion may be provided instead of the two first tapered portions 116 and the second tapered portions 118 which are different from each other in the surface direction, or three or more tapered portions may be provided. May be Further, the shape of the first bonding 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 the same as the cylinder head main body 16 except for the shape of the inner peripheral surface of the opening peripheral portion 32. As shown in FIGS. 12 and 13, in the cylinder head main body 106 before joining to the valve seat 102, the first joint surface 120 of the valve seat 102 and the welded portion 110 are formed on the inner peripheral surface of the opening peripheral portion 32 (FIG. A convex portion 124 annularly protruding from the second bonding surface 122 capable of forming a reference (see reference numeral) and a tapered surface 126 are provided.

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

  As shown in FIG. 13, the tapered surface 126 increases the diameter of the opening peripheral portion 32 from the first starting point portion 128 on one end side (arrow X1 side) on which the convex portion 124 of the second bonding surface 122 rises. Extending in the direction of In addition, as shown in FIG. 16, the tapered surface 126 and the second tapered portion 118 of the valve seat 102 have, for example, the tapered surface 126 and the second tapered portion 118 by making the taper angles substantially equal to each other. The respective shapes are set such that the valve seat 102 and the cylinder head body 106 have a desired bonding positional relationship when the two pieces come into contact with each other. As shown in FIG. 13, the second starting point portion 130 on the other end side where the convex portion 124 of the second bonding surface 122 stands up coincides with the end portion on the center side of the second bonding surface 122.

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

  As described later, when forming the welded portion 110 by resistance welding, the distance between the welded portion 110 and the electrode 74 is closer to the outer side of the cylinder head main body 106 than at the center side, so the current tends to be concentrated. It becomes easy to generate heat. For this reason, it is preferable to make L2 slightly smaller than L1 in order to cause the entire cylinder head body 106 to generate heat more uniformly at the time of resistance welding.

  In the convex portion 124, an angle between the radial direction of the opening peripheral portion 32 and the surface direction of the first surface 132 is γ, and an angle between the axial direction of the opening peripheral portion 32 and the surface direction of the second surface 134 is When δ is set, it is preferable that the relationship of 0 ° <γ = δ <45 ° be established.

  Next, a joining method will be described in which the valve seat 102 and the cylinder head body 106 are joined by forming the weld part 110 from the weld part forming structure 100 described above. In this bonding method, first, as shown in FIG. 14, the valve seat 102 and the cylinder head body 106 are set between a pair of electrodes consisting of the 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 portion 32 face each other at an interval, 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 pair of electrodes in the direction in which they approach each other and performing energization while applying a pressure contact load to the valve seat 102 and the cylinder head body 106. As a result, the contact portion between the valve seat 102 and the cylinder head body 106 generates heat based on the contact resistance, and the convex portion 124 starts to melt. When the valve seat 102 and the cylinder head main body 106 are brought close to each other while discharging the melted convex portion 124 from between the first bonding surface 120 and the second bonding surface 122, as shown in FIG. The portion 124 and the first tapered portion 116 of the first bonding surface 120 are in 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 remaining portion of the first surface 132 without melting and the remaining length of the second surface 134 without melting The resistance welding can be advanced while maintaining the length L2a of the portion being in a substantially equal relationship. The length L1a is a length from the first starting point portion 128 of the remaining first surface 132 to the end portion on the center side in a cross section along the axial direction of the opening peripheral portion 32. The length L2a is a length from the second starting point portion 130 of the remaining second surface 134 to the end on one end side in a cross section along the axial direction of the opening peripheral portion 32.

  In particular, in a cross section along the axial direction of the opening peripheral portion 32, a 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 portion 32 It is preferable that the angle formed be 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 portion 32.

  When substantially the entire protrusion 124 is melted, as shown in FIG. 16, the first joint surface 120 and the second joint surface 122 are in contact with each other to form the welded portion 110, and the second tapered portion 118 One end side of the first bonding surface 120 abuts on the one end side of the second bonding surface 122 of the tapered surface 126. At this time, the energization is stopped immediately before or at the same time the contact between one end of the second tapered portion 118 with respect to the first bonding surface 120 and the one end of the tapered surface 126 with respect to the one bonding surface. And finish the resistance welding.

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

  Next, the effect of the welding part formation structure 100 which concerns on 2nd Embodiment, and a joining method is demonstrated. In the weld forming structure 100 as well, as with the weld forming structure 10 according to the first embodiment, the convex portion 124 is provided on the second joint surface 122 of the opening peripheral portion 32, so the apex 136 of the convex 124 The resistance welding can be started with the first joint surface 120 in line contact. As a result, even when the valve seat 102 and the cylinder head body 106 have a variation in shape, it is possible to suppress the variation in the contact area between the valve seat 102 and the cylinder head body 106 at the beginning of the contact.

  Further, in the welding 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 be advanced while maintaining the relationship in which L1a and L2a are substantially equal. As a result, it is possible to suppress the variation in the length of the path of the current flowing through the convex part 124 (energization distance) at the time of resistance welding among the parts of the convex part 124. Therefore, the valve seat 102 and the cylinder head main body 106 (molten convex part It can suppress that a temperature difference arises in a contact surface with 124).

  In particular, it is preferable that the insulating portion 138 be provided around the outer edge of the surface of the electrode 74 facing the proximal end surface 50 of the valve seat 102. The insulating portion 138 is an air gap or an insulating member provided in the electrode 74, and partially insulates the electrode 74 and the valve seat 102. Thus, by providing the insulating portion 138 in the electrode 74, it is possible to maintain the relationship in which the lengths of the current paths become equal over the entire energization time of the resistance welding.

  Therefore, according to the welded portion forming structure 100, regardless of whether the valve seat 102 and the cylinder head main body 106 have variations in shape or the like, the valve seat can be operated from the start to the end of the resistance welding. The contact surface between 102 and the cylinder head body 106 can be heated substantially uniformly. As a result, it is possible to suppress variation in bonding strength between the valve seat 102 and the cylinder head main body 106, and maintain good bonding quality by the welded portion 110. In other words, it is possible to form a weld portion 110 that can join the valve seat 102 and the cylinder head body 106 well.

  Moreover, in the welding part formation structure 100 which concerns on 2nd Embodiment, the shape of the convex part 124 was set so that the relationship of 0 degree <(gamma) = (delta) <45 degree may be realized. In this case, at the time of resistance welding, the amount of the molten convex portion 124 discharged from between the first joint surface 120 and the second joint surface 122 can be reduced. This makes it possible to reduce the energy required to form the weld 110. In addition, the convex part 124 is not limited to being set to the shape in which the relationship of 0 degree <(gamma) = (delta) <45 degrees is formed, for example, magnitude | sizes of (gamma) and (delta) may mutually differ. . Further, each of γ and δ may be 0 ° or 45 ° or more.

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

  For example, with regard to the convex portions 58, 82, 84 of the weld portion forming structure 10 according to the first embodiment, 0 ° << as in the convex portion 124 of the weld portion forming structure 100 according to the second embodiment. It is good also as a shape which the relation equivalent to gamma = delta <45 degrees holds.

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 satisfying all of α> 0, α ≧ β, and β ≧ 0 holds.

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

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

  Specifically, the first joint surface 34 in the case where the load center points are generated at three locations on 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. The displacement measurement test was carried out. The amount of displacement of the first joint surface 34 from the beginning when the apex 72 of the convex portion 82 abuts on the first joint surface 34 at each of these load center points is taken as the amount of displacement of the valve seat 78. The result of the displacement measurement test for each of these points is shown as Example 1 in FIG. 17A.

  In the joint strength measurement test, the torque applied to the valve seat 78 is gradually increased in a state where the cylinder head main body 16 is fixed, and the magnitude of the torque when the second joint surface 36 and the first joint surface 34 separate. Was determined as the bonding strength. The result of conducting this bonding strength measurement test three times is shown as Example 1 in FIG. 17B.

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

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

[Example 3]
The displacement amount measurement test was performed on the valve seat 78 and the convex portion 82 whose shapes are set in the same manner as in Example 1 in the same manner as in Example 1. The result is shown as Example 3 in FIG. The result of the test is shown as Example 3 in FIG. 18B.

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

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

  From Example 1 to 4 above, the valve seat 78 is deformed by the pressure load by forming the valve seat 78 in such a shape that the relationship satisfying all of b / a ≧ 1 and b / 3 ≧ c ≧ 0 holds. Can be suppressed more effectively. As a result, resistance welding can be performed while the valve seat 78 and the cylinder head main body 16 are in good contact with each other, so that the joint quality by the welded portion 20 can be enhanced.

[Example 5]
The shape of the convex portion 124 shown in FIG. 13 is set to L1 = 1.28 × L2 such that L2 is slightly smaller than L1 (L1 ≧ L2). About this convex part 124 and the valve seat 102 shown in FIG. 12, it carried out similarly to Example 1, and showed the result of having conducted the joint strength measurement test as Example 5 in FIG.

[Example 6]
The shape of the convex portion 124 was set to L1 = (0.738 to 0.952) × L2 such that L2 was slightly larger than L1 (L1 <L2). About this convex part 124 and the valve seat 102 shown in FIG. 12, it carried out similarly to Example 1, and showed the result of having conducted the joint strength measurement test as Example 6 in FIG.

  It can be seen from FIG. 19 that good bond strength can be obtained in both Example 5 and Example 6. Moreover, in Example 5, compared with Example 6, the dispersion | variation in joint strength calculated | required by the joint strength measurement test of 3 times is small, and it turns out that joint strength can be enlarged more stably. Therefore, in the convex portion 124, by making L2 slightly smaller than L1 within the range of 0.7 × L2 ≦ L1 ≦ 1.3 × L2, the contact surface between the valve seat 102 and the cylinder head main body 106 is obtained. By performing resistance welding while heating more uniformly, the joint quality by the welding portion 20 can be further effectively enhanced.

10, 100 Welded structure formation 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 part 33, 114 ... Outer peripheral surface 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 part 60 ... First tapered surface 62 ... Second tapered surface 64, 128 ... First starting point 66, 130 ... Second starting point 68, 132 ... second One surface 70, 134 ... second surface 72, 136 ... vertex 116 ... first tapered portion 118 ... second tapered portion Z ... intersection

Claims (9)

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 the outer peripheral surface of the first metal member is proximal to the distal end side in the insertion direction to the insertion port A tapered first joint surface that expands in diameter toward the side,
On the inner peripheral surface of the insertion port, an annular convex portion projecting from a second joint surface capable of forming a weld portion with the first joint surface, and the one end side on which the convex portion of the second joint surface rises A tapered first tapered surface extending in a direction of expanding the diameter of the insertion opening from the first starting point of the first opening toward the one end of the insertion opening; and the other in which the convex portion of the second bonding surface rises There is provided a tapered second tapered surface extending in a direction in which the diameter of the insertion port is reduced from the second starting point on the end side toward the other end side of the insertion port,
The convex portion extends from the first starting point portion to a first surface extending toward the radial center of the insertion port, and from the second starting point portion to the extending end portion of the first surface. And the second surface forming the corner with the first surface,
Let A be the radial distance between the apex of the corner and the first starting point, and B be the radial distance between the apex and the second starting point, A> 0, AAB. , A relationship satisfying all of B ≧ 0 holds,
And an angle which the first joint surface makes with the axial direction of the first metal member, and a second joint surface which connects the first starting point and the second starting point at the shortest distance make with the axial direction of the insertion port. Weld-formed structure characterized by equal angles. 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 the outer peripheral surface of the first metal member is proximal to the distal end side in the insertion direction to the insertion port A tapered first joint surface that expands in diameter toward the side,
On the inner peripheral surface of the insertion port, an annular convex portion projecting from a second joint surface capable of forming a weld portion with the first joint surface, and the one end side on which the convex portion of the second joint surface rises A tapered first tapered surface extending in a direction of expanding the diameter of the insertion opening from the first starting point of the first opening toward the one end of the insertion opening; and the other in which the convex portion of the second bonding surface rises There is provided a tapered second tapered surface extending in a direction in which the diameter of the insertion port is reduced from the second starting point on the end side toward the other end side of the insertion port,
The convex portion extends from the first starting point portion to a first surface extending toward the radial center of the insertion port, and from the second starting point portion to the extending end portion of the first surface. And the second surface forming the corner with the first surface,
The angle between the first surface and the reference line along the axial direction of the insertion port passing through the apex of the corner on the inner corner side of the corner is α, and the reference line and the second surface are When an angle is β, a relation satisfying all of α> 0, α ≧ β, β ≧ 0 holds.
And an angle which the first joint surface makes with the axial direction of the first metal member, and a second joint surface which connects the first starting point and the second starting point at the shortest distance make with the axial direction of the insertion port. Weld-formed structure characterized by equal angles. 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 the outer peripheral surface of the first metal member is proximal to the distal end side in the insertion direction to the insertion port A first joint surface is provided having a tapered portion that expands in diameter toward the side,
An annular convex portion is provided on an inner circumferential surface of the insertion port, the annular convex portion projecting from a second joining surface capable of forming a welding portion with the first joining surface,
The convex portion is a first surface extending from a first starting point on the one end side where the convex portion of the second bonding surface rises up to a radial center of the insertion port, and the second bonding surface And a second surface extending from the second starting point on the other end side where the convex portion rises up to the extending end of the first surface to form the first surface and a corner portion. ,
Let L1 be the length from the first starting point of the first surface to the vertex of the corner in a cross section along the axis of the insertion slot, and the length from the second starting point to the vertex of the second surface A weld portion forming structure characterized in that the following relationship is satisfied: 0.7 × L 2 ≦ L 1 ≦ 1.3 × L 2, where L 2 is L 2.   The welded part forming structure according to claim 3, wherein L1 and L2 are substantially equal. It is the welding part formation structure in any one of Claims 1-4, Comprising:
When an angle between the radial direction of the insertion opening and the surface direction of the first surface is γ, and an angle between the axial direction of the insertion opening and the surface direction of the second surface is δ, 0 ° <γ The welded portion forming structure characterized in that a relation of δ <45 ° holds. In the welded part forming structure according to any one of claims 1 to 5,
A direction in which the inner peripheral surface of the first metal member extends along the axial direction of the first metal member, and a base end surface which is an end surface on the base end side of the first metal member is the first metal member The direction extending along the radial direction intersects at the intersection,
The proximal end of the inner peripheral surface of the first metal member is coincident with the intersection or separated from the intersection toward the distal end of the first metal member.
The radial center end of the first metal member at the proximal end coincides with the intersection or is spaced apart from the intersection at the radial outer side of the first metal member.
The distance between the end on the tip side of the inner circumferential surface of the first metal member and the intersection is a, and the end on the outer side in the radial direction of the first metal member of the base end and the intersection B / a ≧ 1, b / 3 交差 c ≧, where b is the distance between the end face of the base end face in the radial direction of the first metal member and c is the distance between the intersections. The welded portion forming structure characterized in that a relationship satisfying all of 0 holds. In the weld formation structure according to any one of claims 1 to 6,
The welded portion forming structure, wherein 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 7,
The first metal member is a valve seat,
The second metal member is a cylinder head body,
The said insertion port is an opening peripheral part of the port provided in the said cylinder head main body, The welding part formation structure characterized by the above-mentioned. It is a joining method of the metallic member which forms the said welding part from the welding part formation structure in any one of Claims 1-8, and joins a said 1st metallic member and a said 2nd metallic member,
Bringing the apex of the corner into contact with the first bonding surface;
By applying a pressure contact load to the first metal member and the second metal member while supplying electricity, the molten convex portion is discharged from between the first bonding surface and the second bonding surface, Bringing a metal member and the second metal member close to each other and bringing the first bonding surface into contact with the second bonding surface;
A method of joining metal members, comprising:

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