JP2023009962A - Method and structure for joining metallic component - Google Patents

Abstract

To provide a method and a structure for joining a metallic component, which can join a joined part by suppressing energization caused by burrs.SOLUTION: In a method for joining the metallic component, which joins an outer peripheral surface part 31 of an inner metallic member 3 and an inner peripheral surface part 21 of an outer metallic member 2 with heat generated through energization while pressurization of them is carried out in an axial direction, an insulation part 50 for blocking current flowing through burrs 62 generated when the outer peripheral surface part 31 of the inner metallic member 3 and the inner peripheral surface part 21 of the outer metallic member 2 are joined is disposed near a joined part 60 formed between a joined outer diameter part 32 of the inner metallic member 3 and a joined inner diameter prat 22 of the outer metallic member 2. The joining method forms the joined part 60 between the joined outer diameter part 32 and the joined inner diameter prat 22 with heat generated through energization while the joined outer diameter part 32 of the inner metallic member 3 and the joined inner diameter prat 22 of the outer metallic member 2 are pressurized from one end side in the axial direction toward the other end side in the axial direction.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method of joining metal members and a joining structure of metal members.

A drive source such as an engine and a transmission are arranged in the front part of the vehicle body so that the axis extends in the longitudinal direction of the vehicle body, and the driving force transmitted from the transmission is transmitted from the output shaft for the rear wheels extending to the rear of the vehicle body to the propeller for the rear wheels. A so-called FR (front engine/rear drive)-based vehicle is known in which power is transmitted to rear wheels as main drive wheels via a shaft and a rear wheel differential.

A rear wheel differential device (hereinafter referred to as a differential device) installed in such a vehicle receives power from a rear wheel propeller shaft (hereinafter referred to as a propeller shaft) when the vehicle turns. The drive force is distributed to the corresponding left and right drive wheels to adjust the difference in wheel rotation speed that occurs between the left and right drive wheels.

This differential includes a ring gear to which driving force is transmitted from a propeller shaft, and a differential case that is joined to the ring gear and rotates together. The differential case includes a pair of left and right side gears for distributing the driving force transmitted from the ring gear to the left and right driving wheels, a pinion shaft extending in a direction orthogonal to the ring gear, and a pair of left and right side gears provided on the pinion shaft and meshing with each other. , and a pinion gear for adjusting the difference in wheel rotation speed that occurs between the drive wheels.

As a method of joining the ring gear and the differential case, for example, the differential case, which is the inner metal member, and the ring gear, which is the outer metal member, are pressurized in the axial direction, and the metal at the contact portion is softened by resistance heat generated by energization to generate plastic flow. ring mash bonding is known.

For example, in Patent Document 1, an outer peripheral wall portion of an inner metal member is provided with an outer diameter portion for joining and an inclined surface portion located on at least one of both sides in the axial direction with respect to the outer diameter portion for joining. In the inner peripheral wall portion of the, by providing the inner diameter portion for joining corresponding to the outer diameter portion for joining and the inclined surface portion corresponding to the inclined surface portion of the inner metal member, the outer peripheral wall portion of the inner metal member and the outer metal member When the inner peripheral wall portion is pressurized in the axial direction and the joining outer diameter portion and the joining inner diameter portion are joined to each other by resistive heat generated by energization, the inclined surface portion of the inner metal member and the inclination of the outer metal member are formed. A ring mash joint is disclosed in which the face portions form a tapered mating portion that fits together.

Japanese Patent No. 6119795

The ring mash joining of Patent Document 1 disperses the stress generated when an external force is applied to the outer metal member and the inner metal member to the joint portion and the taper fitting portion, respectively, so stress concentration at the joint portion can be avoided. At the same time, a joint structure that is resistant to repeated impacts can be obtained.

On the other hand, in an actual ring mash joint, softened metal burrs can form extending from the joint. For example, when the inner metal member is made of cast iron and the outer metal member is made of steel, the outer peripheral surface portion of the inner metal member and the inner peripheral surface portion of the outer metal member are axially separated from the other axial end side. When forming a joint where the joint outer diameter part and the joint inner diameter part are joined to each other by resistance heat generated by energization while applying pressure toward one end side, the joint inner diameter part is placed on the axial direction one end side of the joint inner diameter part in the outer metal member. If an inner wall portion extending radially outward from the joint portion is provided, a burr extending radially outward from one axial end side of the joint portion may be formed so as to abut against the inner wall portion. If a burr is formed in contact with the inner wall of the outer metal member, a current will flow through the burr, and the current will divert to both the joint and the burr, which may make it impossible to join the joint well. be.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a metal member joining method and a metal member joining structure capable of suppressing energization due to burrs and joining the joints satisfactorily.

In order to solve the above problems, the present invention is characterized by the following configuration.

First, the present invention is a method for joining metal members by applying pressure to the outer peripheral surface portion of the inner metal member and the inner peripheral surface portion of the outer metal member in the axial direction and joining them by resistance heat generated by energization,
forming a joining outer diameter portion on the outer peripheral surface portion of the inner metal member;
forming a joint inner diameter portion corresponding to the joint outer diameter portion on the inner peripheral surface portion of the outer metal member;
In the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the outer peripheral surface portion of the inner metal member and the inner circumference of the outer metal member are provided. arranging an insulating part that prevents the current flowing through the burrs generated when joining the face part,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by the energization causes the outer diameter joint portion and the joint inner diameter portion. forming the joint with the joint inner diameter;
It is characterized by

According to the present invention, by arranging the insulating portion in the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the joint outer diameter of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end in the axial direction toward the one end in the axial direction, and resistance heat is generated by energization to form a joint between the joint outer diameter portion and the joint inner diameter portion. Sometimes, when the outer metal member is provided with an inner wall portion that is located on one end side in the axial direction with respect to the inner diameter portion of the joint and extends radially outward from the inner diameter portion of the joint, It is possible to prevent the burr extending radially outward from the one end side from coming into contact with the inner wall portion of the outer metal member. Therefore, the flow of current through the burr is suppressed, and the current flows intensively in the joint, so that the joint can be properly joined.

Further, the joint portion may be reheated by resistive heat generated by re-energizing the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member.

According to this configuration, when the joint portion is reheated by resistance heat generated by re-energizing the inner metal member and the outer metal member, current flow through the burr is suppressed, and the current flows intensively in the joint portion. By heating the joint portion by resistance heating, the joint portion can be tempered, and the strength of the joint portion can be improved.

Further, the outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
The insulating portion may be paint applied to the inner wall portion.

According to this configuration, the insulating portion is provided by coating the inner wall portion of the outer metal member with, for example, cationic coating. Therefore, the paint can prevent current from flowing through the burr.

Further, the outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
The insulating portion may be a paper sheet member disposed on the inner wall portion.

According to this configuration, the insulating portion is provided by arranging the paper sheet member on the inner wall portion of the outer metal member. Thus, the sheet of paper member can prevent current from flowing through the burrs.

forming a fitting taper outer diameter portion located on one end side in the axial direction with respect to the joining outer diameter portion on the outer peripheral surface portion of the inner metal member;
forming a fitting taper inner diameter portion corresponding to the fitting taper outer diameter portion on the inner peripheral surface portion of the outer metal member;
The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
The insulating portion may be provided from the inner wall portion of the outer metal member to the fitting taper inner diameter portion.

According to this configuration, by providing the insulating portion from the inner wall portion of the outer metal member to the fitting taper inner diameter portion, the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are separated from the other axial end side. When the joint is formed between the joint outer diameter portion and the joint inner diameter portion by resistive heat generated by applying pressure toward one end in the axial direction and energizing, the burr abuts against the inner wall portion of the outer metal member due to the insulating portion. can be suppressed, and the joint can be satisfactorily joined. Moreover, when stress acts between the inner metal member and the outer metal member, the taper fitting portion can suppress stress concentration on the joint portion. Furthermore, since the insulating portion is disposed between the fitting taper outer diameter portion and the fitting taper inner diameter portion, when the inner metal member and the outer metal member are re-energized and the joint portion is heated again by resistance heat generation, No current flows through the taper fitting. Therefore, when the current is re-energized, the current flows intensively in the joints, so the joints are heated by the resistance heat generation, so that the joints can be tempered and the strength of the joints can be improved. can be planned.

Further, the outer peripheral surface portion of the inner metal member is provided with a first fitting tapered outer diameter portion positioned on one axial end side with respect to the joint outer diameter portion, and a first fitting tapered outer diameter portion positioned on the axial direction one end side with respect to the joint outer diameter portion, and an axial direction other end side with respect to the joint outer diameter portion. forming a second mating tapered outer diameter located on the side of the
A first fitting taper inner diameter portion corresponding to the first fitting taper outer diameter portion and a second fitting taper outer diameter portion corresponding to the second fitting taper outer diameter portion are formed on the inner peripheral surface portion of the outer metal member. forming a mating tapered inner diameter and
The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
The insulating portion is provided on the inner wall portion,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized in the axial direction, and the joint is formed between the joint outer diameter portion and the joint inner diameter portion by resistive heat generated by energization. When forming the portion, the first fitting taper outer diameter portion and the second fitting taper outer diameter portion of the inner metal member and the first fitting taper inner diameter portion and the second fitting taper outer diameter portion of the outer metal member. The two mating taper inner diameters may be mated to form a first taper mating section and a second taper mating section.

According to this configuration, the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by energization causes the joint outer diameter portion and the joint inner diameter portion, a first tapered fitting portion and a second tapered fitting portion are provided on both axial sides of the joint portion. The first tapered fitting portion and the second tapered fitting portion provided on both sides in the axial direction of the joint portion can further suppress stress concentration on the joint portion.

Also, the inner metal member may be a differential case, and the outer metal member may be a ring gear.

According to this configuration, since the inner metal member is the differential case and the outer metal member is the ring gear, the joint portion between the differential case and the ring gear can be satisfactorily joined.

Further, the present invention provides a joining structure of metal members, wherein the outer peripheral surface portion of the inner metal member and the inner peripheral surface portion of the outer metal member are axially pressurized and joined by resistance heat generation due to energization,
A bonding outer diameter portion is formed on the outer peripheral surface portion of the inner metal member,
A joint inner diameter portion corresponding to the joint outer diameter portion is formed on the inner peripheral surface portion of the outer metal member,
In the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the outer peripheral surface portion of the inner metal member and the inner circumference of the outer metal member are provided. An insulating part is provided to prevent current flowing through burrs generated when joining the face part,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by the energization causes the outer diameter joint portion and the joint inner diameter portion. The joint portion is formed between the joint inner diameter portion,
It is characterized by

According to the present invention, by arranging the insulating portion in the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the joint outer diameter of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end in the axial direction toward the one end in the axial direction, and resistance heat is generated by energization to form a joint between the joint outer diameter portion and the joint inner diameter portion. Sometimes, when the outer metal member is provided with an inner wall portion that is located on one end side in the axial direction with respect to the inner diameter portion of the joint and extends radially outward from the inner diameter portion of the joint, It is possible to prevent the burr extending radially outward from the one end side from coming into contact with the inner wall portion of the outer metal member. Therefore, the flow of current through the burr is suppressed, and the current flows intensively in the joint, so that the joint can be properly joined.

Therefore, according to the method for joining metal members and the structure for joining metal members according to the present invention, the conduction due to burrs can be suppressed, and the joints can be satisfactorily joined.

1 is a schematic diagram showing a differential device having a joint structure for metal members according to an embodiment of the present invention; FIG. FIG. 2 is a partially enlarged view of a range surrounded by a dashed-dotted circle II in FIG. 1; It is explanatory drawing explaining the joining method of a metal member. FIG. 4 is a partially enlarged view of a range surrounded by a dashed-dotted circle IV in FIG. 3 ; FIG. 4 is a schematic diagram showing transition of energization output when joining metal members. FIG. 11 is a schematic diagram showing an insulation part in another embodiment; FIG. 4 is a schematic diagram showing a differential device having a joint structure for metal members according to another embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a differential device having a joint structure for metal members according to an embodiment of the present invention. As shown in FIG. 1, a differential device having a joint structure of metal members according to an embodiment of the present invention is configured as a differential device 1 for rear wheels of a front-engine, rear-drive vehicle.

The differential device 1 includes a ring gear 2 configured as an outer metal member of the differential device 1 and a differential case 3 configured as an inner metal member of the differential device 1 . This ring gear 2 is a bevel gear made of carbon steel. Further, the differential case 3 is a substantially cylindrical component made of cast iron.

The ring gear 2 has a substantially cylindrical inner peripheral surface portion 21 . A joining inner diameter portion 22 extending in the axial direction of the ring gear 2 is formed in the inner peripheral surface portion 21 . Bevel teeth 25 are provided on the outer circumference of the ring gear 2 at the other end in the axial direction.

FIG. 2 is a partial enlarged view of the area surrounded by a dashed-dotted circle II in FIG.

The inner peripheral surface portion 21 of the ring gear 2 is provided with an inner wall portion 24 which is positioned on one axial end side of the joint inner diameter portion 22 and extends radially outward in a substantially straight line.

Returning to FIG. 1 , the differential case 3 includes a substantially cylindrical outer peripheral surface portion 31 . A substantially cylindrical joint extending in the axial direction of the differential case 3 and having an outer diameter approximately equal to the joint inner diameter portion 22 of the ring gear 2 so as to be fitted to the joint inner diameter portion 22 of the ring gear 2 . An outer diameter portion 32 is formed. The differential case 3 also includes a substantially spherical internal space 33 formed inside the outer peripheral surface portion 31 . Further, the outer peripheral surface portion 31 of the differential case 3 is provided with a substantially circular flange 34 that is positioned on one axial end side of the joint outer diameter portion 32 and extends radially outward.

A fitting that is located on one axial end side with respect to the joining outer diameter portion 32 to the radially outer end portion of the flange 34 of the outer peripheral surface portion 31 of the differential case 3 and is inclined toward the one axial end side of the differential case 3 toward the outside. A tapered outer diameter portion 35 is formed. On the other hand, on the inner peripheral surface portion 21 of the ring gear 2, a fitting tapered inner diameter portion is located on the one axial end side with respect to the joint inner diameter portion 22 and the inner wall portion 24 and is inclined toward the one axial end side of the ring gear 2 toward the outside. 23 are formed. The fitting taper outer diameter portion 35 and the fitting taper inner diameter portion 23 are formed to be inclined at the same angle so that they can be fitted to each other.

Further, inside the outer peripheral surface portion 31, the differential case 3 has a shaft hole 41 extending in a direction perpendicular to the axis of the outer peripheral surface portion 31 so as to pass through the internal space 33, and a pinion shaft 42 attached to extend through the shaft hole 41. and are arranged. A pinion gear (not shown) housed in the internal space 33 is connected to the pinion shaft 42 .

In the present embodiment, the inner wall portion 24 of the ring gear 2 located near the joint portion 60 formed between the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2 has an outer peripheral surface portion of the differential case 3. A paint 50 configured as an insulating portion is provided to prevent current from flowing through burrs 62 generated when 31 and the inner peripheral surface portion 21 of the ring gear 2 are joined. The fitting tapered inner diameter portion 23 is also provided with a paint 50 configured as an insulating portion. The paint 50 is applied to the surfaces of the inner wall portion 24 and the fitting taper inner diameter portion 23 by cationic coating.

Next, a method of joining the ring gear 2 and the differential case 3 will be described.

FIG. 3 is an explanatory diagram illustrating a method of joining metal members.

As the first energizing step, first, the differential case 3 is formed with the joint outer diameter portion 32 and the fitting tapered outer diameter portion 35 located on one end side in the axial direction with respect to the joint outer diameter portion 32 on the outer peripheral surface portion 31. prepare. Next, a ring gear 2 is prepared in which a joint inner diameter portion 22 corresponding to the joint outer diameter portion 32 and a fitting taper inner diameter portion 23 corresponding to the fitting taper outer diameter portion 35 are formed on the inner peripheral surface portion 21 . The paint 50 is simultaneously applied to the inner wall portion 24 of the ring gear 2 and the fitting taper inner diameter portion 23 . The differential case 3 described above is inserted into the ring gear 2, and the other axial end side of the joint outer diameter portion 32 of the differential case 3 and the axial direction one end side of the joint inner diameter portion 22 of the ring gear 2 are brought into contact over the entire circumference. As a result, the ring gear 2 and the differential case 3 are coaxial.

FIG. 4 is a partially enlarged view of a range surrounded by a dashed-dotted circle IV in FIG.

In practice, the joint outer diameter portion 32 of the differential case 3 is formed to have a larger diameter than the joint inner diameter portion 22 so as to overlap the joint inner diameter portion 22 of the ring gear 2 in the radial direction, and the overlap margin is 0.6 mm. formed in

Returning to FIG. 3, annular electrodes 51 and 52 are installed on the other axial end of the inner peripheral surface portion 21 of the ring gear 2 and one axial end of the flange 34 of the differential case 3, respectively. The electrodes 51 and 52 are arranged so as to axially sandwich the joint inner diameter portion 22 of the ring gear 2 and the joint outer diameter portion 32 of the differential case 3 and to approach each other in the radial direction as much as possible. The electrodes 51 and 52 are electrically connected to a controller 53 so that the energization output is controlled. A motor 54 is arranged between the electrode 51 and the controller 53 to move the electrode 51 in the axial direction. The motor 54 is configured to pressurize the ring gear 2 and the differential case 3 in the axial direction by moving the electrode 51 toward one end in the axial direction.

Next, the ring gear 2 and the differential case 3 are pressurized in the axial direction through the electrodes 51 and 52 and energized by the controller 53 to perform ring mash joining. The current supplied from the controller 53 indicated by the dashed line in FIG. and flows to the electrode 52 on the differential case 3 side. Due to this energization, the radially overlapped portion of the joint outer diameter portion 32 and the joint inner diameter portion 22 heats up to about 900° C. due to resistance heat generation, softens, and undergoes plastic flow.

5A and 5B are schematic diagrams showing changes in output of energization during welding of metal members. FIG. As shown in FIG. 5, the controller 53 keeps the output of the current flowing from the electrode 51 on the side of the ring gear 2 to the electrode 52 on the side of the differential case 3 to a constant output P1 from the start of energization as described above until the time T1. to maintain.

Since the differential case 3 and the ring gear 2 are pressurized in the axial direction, heat generation, softening, and plastic flow in the overlapped portion between the joint outer diameter portion 32 and the joint inner diameter portion 22 proceed in the pressurizing direction. 1, the ring gear 2 is pushed against the differential case 3 until the fitting tapered inner diameter portion 23 of the ring gear 2 comes into contact with the fitting tapered outer diameter portion 35 of the differential case 3 via the paint 50. pushed in. At this time, the softened metal burr is formed so as to gradually extend radially outward from the one axial end side in the overlapped portion of the joint outer diameter portion 32 and the joint inner diameter portion 22 .

When time T1 elapses after the start of energization, the fitting tapered inner diameter portion 23 of the ring gear 2 comes into contact with the fitting tapered outer diameter portion 35 of the differential case 3 via the paint 50 . At this time, the controller 53 temporarily reduces the output of the current flowing from the electrode 51 on the ring gear 2 side to the electrode 52 on the differential case 3 side to zero.

The joint inner diameter portion 22 of the ring gear 2 and the joint outer diameter portion 32 of the differential case 3 form a joint portion 60 by ring mash joining. The fitting tapered inner diameter portion 23 of the ring gear 2 is fitted to the fitting tapered outer diameter portion 35 of the differential case 3 via the paint 50 to form a tapered fitting portion 61 . A burr 62 curved in an arc shape toward the one axial end side is formed along the radially outer side of the joint portion 60 at the one axial end side. The burr 62 extends toward the inner wall portion 24 of the ring gear 2 , and when the burr 62 becomes large and approaches the inner wall portion 24 of the ring gear 2 , the burr 62 comes into contact with the inner wall portion 24 of the ring gear 2 via the paint 50 .

Returning to FIG. 5, in the above-described first energization step, when time T1 has elapsed since the start of energization, the output of the current flowing from the electrode 51 on the side of the ring gear 2 to the electrode 52 on the side of the differential case 3 temporarily becomes zero. After that, when a certain period of time has passed, the second energization step is started.

In this embodiment, the second energization step is started at time T2 after 3 to 4 seconds have passed from time T1.

In the second energization step, the electrodes 51 and 52 are used to heat the junction 60 between the ring gear 2 and the differential case 3 by resistive heat generated by re-energization. At this time, the output of the current flowing from the electrode 51 on the side of the ring gear 2 to the electrode 52 on the side of the differential case 3 is increased because the joint portion 60 formed between the joint inner diameter portion 22 and the joint outer diameter portion 32 is large. , to maintain a power P2 that is 120-130% greater than the power P1.

Returning to FIG. 1, the current supplied from the controller 53 indicated by the dashed line in FIG. 60 and flows to the electrode 52 on the differential case 3 side. On the other hand, since paint 50 is disposed as an insulating portion between the fitting taper inner diameter portion 23 of the ring gear 2 and the fitting taper outer diameter portion 35 of the differential case 3, the current flows through the fitting taper inner diameter portion 23. It does not flow through the tapered fitting portion 61 between the fitting tapered outer diameter portion 35 . Further, even when the burr 62 extending from the joint portion 60 comes into contact with the inner wall portion 24 of the ring gear 2 through the paint 50, the paint 50 is provided as an insulating portion between the inner wall portion 24 of the ring gear 2 and the burr 62. Therefore, current does not flow from the inner wall portion 24 toward the burr 62 . Therefore, since the current does not divert into three directions of joint 60, taper fitting 61 and burr 62, joint 60 can be heated again to a tempering temperature such as about 700°C. After energization for a set time such as 2 seconds from time T2 shown in FIG. 5, the energization is stopped. Thereby, the joint portion 60 is tempered.

Although the first energization step and the second energization step are performed in this embodiment, only the first energization step may be performed.

As described above, in the metal member joining structure according to the embodiment of the present invention, the inner wall portion 24 and the fitting taper inner diameter portion 23 of the ring gear 2 are provided with the paint 50 configured as an insulating portion that blocks current. ing.

In the metal joining according to the embodiment of the present invention, in the vicinity of the joint portion 60 formed between the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2, the outer peripheral surface portion 31 of the differential case 3 and the ring gear A paint 50 is provided to block the current flowing through the burr 62 generated when joining the inner peripheral surface portion 21 of the ring gear 2 and the outer diameter portion 32 of the differential case 3 and the inner peripheral portion 22 of the ring gear 2 in the axial direction. A first energization step of forming a joint 60 between the joint outer diameter portion 32 and the joint inner diameter portion 22 by resistance heat generated by energization while applying pressure from the side toward the axial direction one end side, and the joint outer diameter of the differential case 3 and a second energization step of reheating the joint portion 60 by resistance heat generated by re-energizing the portion 32 and the joint inner diameter portion 22 of the ring gear 2 .

By disposing the paint 50 in the vicinity of the joint portion 60 formed between the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2, the joint outer diameter portion 32 of the differential case 3 and the ring gear 2 When the joint 60 is formed between the joint outer diameter portion 32 and the joint inner diameter portion 22 by resistive heat generation due to energization while pressurizing the joint inner diameter portion 22 from the axial direction other end side toward the axial direction one end side. In the case where the ring gear 2 is provided with an inner wall portion 24 which is located on one end side in the axial direction with respect to the joint inner diameter portion 22 and extends radially outward from the joint inner diameter portion 22 , the paint 50 may It is possible to prevent the burr 62 extending radially outward from the direction one end side from coming into contact with the inner wall portion 24 of the ring gear 2 . Therefore, current flow through the burr 62 is suppressed, and the current flows intensively in the joint portion 60, so that the joint portion 60 can be joined satisfactorily.

In addition, the current flow through the burr 62 is suppressed by the second energization step in which the joint portion 60 is heated again by resistance heat generated by re-energizing the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2. Since the current flows intensively in the joint 60, the joint 60 is heated by the resistance heating, so that the joint 60 can be tempered and the strength of the joint 60 can be improved.

In addition, by providing the paint 50 from the inner wall portion 24 of the ring gear 2 to the fitting taper inner diameter portion 23, the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2 are separated from the axial direction other end side to the axial direction one end side. The burr 62 is brought into contact with the inner wall portion 24 of the ring gear 2 by the paint 50 when the joint portion is formed between the joint outer diameter portion 32 and the joint inner diameter portion 22 by resistive heat generated by energization while applying pressure toward the side. can be suppressed, and the joint portion 60 can be joined satisfactorily. Further, when stress acts between the differential case 3 and the ring gear 2 , the stress concentration on the joint portion 60 can be suppressed by the tapered fitting portion 61 . Furthermore, since the paint 50 is disposed between the fitting taper outer diameter portion 35 and the fitting taper inner diameter portion 23, when the differential case 3 and the ring gear 2 are energized again, the joint portion 60 is heated again by resistive heat generation. , no current flows through the taper fitting 61 . Therefore, when the current is re-energized, the current flows intensively in the joint 60, so that the joint 60 is heated by resistance heat generation, so that the joint 60 can be tempered. It is possible to improve the strength of

Further, since the inner metal member is the differential case 3 and the outer metal member is the ring gear 2, the joint portion 60 between the differential case 3 and the ring gear 2 can be satisfactorily joined.

Further, the paint 50 is provided by applying paint to the inner wall portion 24 of the ring gear 2, for example, by performing cationic painting. Therefore, the paint 50 can prevent current from flowing through the burr 62 .

FIG. 6 is a schematic diagram showing the insulation in another embodiment.

In the above-described embodiment, the paint 50 configured as the insulating portion is disposed on the inner wall portion 24 and the fitting taper inner diameter portion 23 of the ring gear 2. However, the annular paper sheet member 150 shown in FIG. It may be provided as an insulating portion by being attached to the inner wall portion 24 and the fitting taper inner diameter portion 23 with an adhesive. This paper sheet member 150 is hereinafter referred to as a paper packing. The paper packing 150 has a substantially conical shape, and includes an upper surface portion 151 that extends in a radial direction substantially perpendicular to the axial direction, and an inclined side surface portion 152 that inclines toward one end in the axial direction of the ring gear 2 toward the outside. have

The upper surface portion 151 of the paper packing 150 is attached to the inner wall portion 24 of the ring gear 2 , and the inclined side surface portion 152 of the paper packing 150 is attached to the fitting tapered inner diameter portion 23 of the ring gear 2 . Therefore, the paper packing 150 can prevent current from flowing through the burr 62 .

FIG. 7 is a schematic diagram showing a differential device having a joint structure for metal members according to another embodiment of the present invention.

In the above-described embodiment, the ring gear 2 is provided with one fitting taper inner diameter portion 23, and the differential case 3 is provided with one fitting taper outer diameter portion 35. However, FIG. A first fitting taper inner diameter portion 223a and a second fitting taper inner diameter portion 223b, and a first fitting taper outer diameter portion 235a and a second fitting taper outer diameter portion 235b are connected to the ring gear 202 and the differential case 203. Each may be provided.

As shown in FIG. 7, it is located at one axial end side of the joint outer diameter portion 232 at the radially outer end portion of the flange 234 of the outer peripheral surface portion 231 of the differential case 203, and extends outward in the axial direction of the differential case 203. A first fitting tapered outer diameter portion 235a is formed which is inclined toward one end. A second fitting taper outer diameter is located on the outer peripheral surface portion 231 of the differential case 203 on the other axial end side with respect to the joint outer diameter portion 232 and is inclined toward the one axial end side of the differential case 203 toward the outside. A portion 235b is formed. On the other hand, on the inner peripheral surface portion 221 of the ring gear 202, a first fitting tapered inner diameter portion 223a is located on the one axial end side of the joint inner diameter portion 222 and is inclined toward the one axial end side of the ring gear 202 toward the outside. is formed. Further, a second fitting tapered inner diameter portion is located on the inner peripheral surface portion 221 of the ring gear 202 on the other end side in the axial direction with respect to the joint inner diameter portion 222 and is inclined toward the one end side in the axial direction of the ring gear 202 toward the outside. 223b is formed.

The first mating taper outer diameter 235a and the second mating taper outer diameter 235b, and the first mating taper inner diameter 223a and the second mating taper inner diameter 223b described above can be fitted together. are formed so as to incline at the same angle. Paints 250a and 250b, which are configured as insulating portions, are provided on the inner wall portion 224 and the first fitting taper inner diameter portion 223a and the second fitting taper inner diameter portion 223b, respectively.

In the present embodiment, the joint outer diameter portion 32 of the differential case 3 and the joint inner diameter portion 22 of the ring gear 2 are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by energization causes the joint outer diameter portion 32 and the joint inner diameter portion 22, the first fitting taper outer diameter portion 235a and the second fitting taper outer diameter portion 235b of the differential case 203 and the first fitting taper outer diameter portion 235b of the ring gear 202 are formed. The mating taper inner diameter portion 223a and the second fitting taper inner diameter portion 223b are fitted to form a first taper fitting portion 261a and a second taper fitting portion 261b, respectively. Thereby, stress concentration on the joint portion 260 can be further suppressed.

Also in this case, instead of the paint as the insulating portion, an insulating portion such as paper packing may be provided.

The present invention is not limited to the illustrated embodiments, and various improvements and design changes are possible without departing from the gist of the invention.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, energization due to burrs can be suppressed and joints can be satisfactorily joined.

2 Outer metal member (ring gear)
3 Inner metal member (differential case)
21 inner peripheral surface portion 22 joint inner diameter portion 31 outer peripheral surface portion 32 joint outer diameter portion 50 insulating portion (paint)
60 joint 62 burr

Claims (8)

A method for joining metal members by applying pressure to an outer peripheral surface portion of an inner metal member and an inner peripheral surface portion of an outer metal member in an axial direction and by resistance heat generation due to energization, the method comprising:
forming a joining outer diameter portion on the outer peripheral surface portion of the inner metal member;
forming a joint inner diameter portion corresponding to the joint outer diameter portion on the inner peripheral surface portion of the outer metal member;
In the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the outer peripheral surface portion of the inner metal member and the inner circumference of the outer metal member are provided. arranging an insulating part that prevents the current flowing through the burrs generated when joining the face part,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by the energization causes the outer diameter joint portion and the joint inner diameter portion. forming the joint with the joint inner diameter;
A method for joining metal members, characterized by: 2. The metal member according to claim 1, wherein the joint portion is reheated by resistive heat generated by re-energizing the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member. Joining method. The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
3. The method of joining metal members according to claim 1, wherein the insulating portion is a paint applied to the inner wall portion. The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
3. The method of joining metal members according to claim 1, wherein the insulating portion is a paper sheet member disposed on the inner wall portion. forming a fitting tapered outer diameter portion positioned on one end side in the axial direction with respect to the joining outer diameter portion on the outer peripheral surface portion of the inner metal member;
forming a fitting taper inner diameter portion corresponding to the fitting taper outer diameter portion on the inner peripheral surface portion of the outer metal member;
The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
5. The method of joining metal members according to claim 1, wherein the insulating portion is provided from the inner wall portion of the outer metal member to the fitting tapered inner diameter portion. The outer peripheral surface portion of the inner metal member is provided with a first fitting tapered outer diameter portion located on one axial end side with respect to the joint outer diameter portion, and a first fitting tapered outer diameter portion positioned on the axial direction other end side with respect to the joint outer diameter portion. forming a second mating tapered outer diameter located at
A first fitting taper inner diameter portion corresponding to the first fitting taper outer diameter portion and a second fitting taper outer diameter portion corresponding to the second fitting taper outer diameter portion are formed on the inner peripheral surface portion of the outer metal member. forming a mating tapered inner diameter and
The outer metal member is provided with an inner wall portion located on one end side in the axial direction with respect to the joint inner diameter portion and extending radially outward from the joint inner diameter portion,
The insulating portion is provided on the inner wall portion,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized in the axial direction, and the joint is formed between the joint outer diameter portion and the joint inner diameter portion by resistive heat generated by energization. When forming the portion, the first fitting taper outer diameter portion and the second fitting taper outer diameter portion of the inner metal member and the first fitting taper inner diameter portion and the second fitting taper outer diameter portion of the outer metal member. 5. A first taper fitting portion and a second taper fitting portion are formed by fitting with two fitting tapered inner diameter portions. A method for joining metal members. 7. The method of joining metal members according to claim 1, wherein the inner metal member is a differential case, and the outer metal member is a ring gear. A joining structure of metal members in which an outer peripheral surface portion of an inner metal member and an inner peripheral surface portion of an outer metal member are axially pressurized and joined by resistance heat generation due to energization,
A bonding outer diameter portion is formed on the outer peripheral surface portion of the inner metal member,
A joint inner diameter portion corresponding to the joint outer diameter portion is formed on the inner peripheral surface portion of the outer metal member,
In the vicinity of the joint formed between the joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member, the outer peripheral surface portion of the inner metal member and the inner circumference of the outer metal member are provided. An insulating part is provided to prevent current flowing through burrs generated when joining the face part,
The joint outer diameter portion of the inner metal member and the joint inner diameter portion of the outer metal member are pressurized from the other end side in the axial direction toward the one end side in the axial direction, and the resistance heat generated by the energization causes the outer diameter joint portion and the joint inner diameter portion. The joint portion is formed between the joint inner diameter portion,
A joint structure for metal members, characterized by:

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