JP5399663B2 - Method for joining pipe and member to be joined - Google Patents

Description

  The present invention relates to a method for joining a pipe and a member to be joined (for example, a bracket or a flange) and a joining apparatus.

  Conventionally, a method of joining a member to be joined to a pipe by inserting the pipe into an insertion hole provided in the member to be joined and then expanding (pipe-expanding) the insertion portion of the pipe into the insertion hole is conventionally performed. More known. By this joining method, a joined structure in which a member to be joined is joined to the pipe is manufactured.

  In this joining method, the following method is known as a method for improving the slip torque of the joined structure. That is, an engagement groove portion extending in the axial direction is provided in advance on the inner peripheral surface of the insertion hole of the member to be joined, and the pipe insertion portion is expanded so that the portion corresponding to the engagement groove portion of the pipe is pushed into the engagement groove portion. Process. This improves the slip torque.

As an expanding method, a tube expanding method by electromagnetic forming or a tube expanding method by a pressure medium (liquid, gas, rubber, etc.) is known (see, for example, Patent Document 1), and further, a tube expanding by using an expanding die. A method is also known (see, for example, Patent Documents 2 to 4). A die that is divided into a plurality of die segments in the circumferential direction is used.
JP-A-7-116751 Japanese Patent Laid-Open No. 1-125506 JP 2000-326028 A JP-A-7-2223030

  Thus, there have been some drawbacks in the method of expanding by electromagnetic forming or the method of expanding by pressure medium. This defect will be described with reference to FIGS.

  In these drawings, 115 is a member to be joined, and 111 is a pipe having a circular cross section. As shown in FIGS. 14B and 14C, the member to be joined 115 has an insertion hole 116, and a plurality of engaging groove portions 118 extending in the axial direction are formed on the inner peripheral surface 117 of the insertion hole 116. Further, as shown in FIG. 14A, a short cylindrical seat 115a is integrally formed on the periphery of the insertion hole 116 of the member to be joined 115 so as to surround the insertion hole 116. 14A and 14B, the pipe 111 is inserted into the insertion hole 116 of the member 115 to be joined. Further, in this state, the insertion portion 112a of the pipe 111 into the insertion hole 116 is replaced with the pipe 111. When the pressure medium 130 filled in the hollow portion 113 is pressurized in the radially outward direction of the pipe 111, the insertion portion 112 a of the pipe 111 is expanded, whereby the member to be joined 115 is joined to the pipe 111. Thus, the joined structure S2 is manufactured. In this joining method, as shown in FIG. 14C, the pipe 111 is shear-deformed at both edge portions 118d and 118d of the engaging groove portion 118 of the joined member 115 and the thickness thereof is locally reduced. There is a drawback in that the torsional strength (slip torque) of the bonded member 115 is reduced. Furthermore, in this joining method, as shown in FIG. 14A, it is necessary to restrain a portion of the pipe 111 that is not expanded by the restraining jig 120 so as not to be expanded. There was a drawback of being expensive.

  Moreover, generally high intensity | strength is required about the joining strength of a pipe and a to-be-joined member. However, in the conventional joining method, the joint strength between the pipe and the member to be joined may be insufficient.

  The present invention has been made in view of the above-described technical background, and an object thereof is to provide a joining method and joining apparatus for a pipe and a member to be joined, which can improve the joining strength between the pipe and the member to be joined. There is.

  The present invention provides the following means.

[1] Using an expanding die that is divided into a plurality of die segments in the circumferential direction,
In a state where the pipe is inserted into the insertion hole provided in the member to be joined, the radius of the pipe is determined by inserting each of the die segments of the die disposed in the hollow portion of the pipe into the insertion hole of the pipe. By pressing outwardly, the insertion portion of the pipe is expanded, thereby joining the member to be joined to the pipe.
On the inner peripheral surface of the insertion hole of the member to be joined, an engagement groove is provided,
In the middle of expanding the insertion part of the pipe, the engagement groove part elastically expanded by pressing both side parts of the engagement groove part of the member to be joined to the outside of the pipe radius by the die segment through the pipe. A method for joining a pipe and a member to be joined, wherein a portion corresponding to the engagement groove portion of the pipe is pushed in.

  [2] The method for joining the pipe and the member to be joined according to item 1 above, in which the portion corresponding to the engagement groove portion of the pipe is pressed in the radially outward direction of the pipe by the pushing protrusion provided on the die segment and pushed into the engagement groove portion.

  [3] Before the portion corresponding to the engagement groove portion of the pipe comes into contact with the bottom surface of the engagement groove portion, both side portions of the engagement groove portion of the member to be joined are respectively pressed by the pressing protrusions provided on the die segment via the pipe. 3. The method for joining a pipe and a member to be joined according to the preceding item 1 or 2, wherein the engaging groove is expanded by pressing outward in the radius direction.

[4] Before the portion corresponding to the engagement groove portion of the pipe comes into contact with the bottom surface of the engagement groove portion, both side portions of the engagement groove portion of the member to be joined are pressed by the pressing protrusions provided on the die segment via the pipe. While elastically expanding the engagement groove by pressing in the radially outward direction,
Press the pipe corresponding to the engaging groove part of the pipe in the outward direction of the radius of the pipe with the pressing convex part provided in the die segment, and press it into the engaging groove part.
The wall thickness of the pipe is t,
The width of the engaging groove is b1,
When the width of the indentation convex part is b2,
The joining method of the pipe of Claim 1 and the to-be-joined member in which b1 and b2 satisfy following Formula (1).
0.8b1-2t ≦ b2 ≦ 1.5b1-2t (1)

[5] The depth of the engaging groove is h1,
The protrusion height of the indentation convex part is h2,
When the protrusion height of the pressing convex part is h3,
5. A method for joining a pipe and a member to be joined according to item 4 above, wherein h1, h2, and h3 satisfy the following expressions (2) and (3).
h1 ≦ h2 + t (2)
h3 ≦ h2 (3)

  [6] The method for joining a pipe and a member to be joined according to any one of the preceding items 1 to 5, wherein the engagement groove portion extends in the axial direction.

[7] An expanding die that is divided into a plurality of die segments in the circumferential direction,
In a state where the pipe is inserted into the insertion hole provided in the member to be joined, the radius of the pipe is determined by inserting each of the die segments of the die disposed in the hollow portion of the pipe into the insertion hole of the pipe. By pressing outwardly, the insertion part of the pipe is expanded, thereby joining the member to be joined to the pipe, and a joining device between the pipe and the member to be joined,
On the inner peripheral surface of the insertion hole of the member to be joined, an engagement groove is provided,
By pressing both side portions of the engagement groove portion of the member to be joined to the engagement groove portion that is elastically expanded by pressing the die segment with the die segment in the radial direction of the pipe so that the engagement groove portion corresponding portion of the pipe is pushed. In addition, the apparatus for joining a pipe and a member to be joined is characterized in that the pipe insertion portion is expanded.

  [8] The joining device for a pipe and a member to be joined according to [7], wherein the die segment has a pressing convex portion that presses the portion corresponding to the engaging groove portion of the pipe and pushes into the engaging groove portion.

  [9] The die segment presses both side portions of the engagement groove portion of the member to be joined to each other in the radial direction of the pipe through the pipe before the corresponding portion of the engagement groove portion of the pipe contacts the bottom surface of the engagement groove portion. The joining apparatus of the pipe of said clause 7 or 8 which has a press convex part which expands an engagement groove part elastically by this, and a to-be-joined member.

[10] The die segment presses the corresponding portion of the pipe into the engaging groove portion and pushes it into the engaging groove portion, and before the portion of the pipe corresponding to the engaging groove portion contacts the bottom surface of the engaging groove portion, A pressing protrusion that elastically expands the engaging groove by pressing both sides of the engaging groove in the radially outward direction of the pipe through the pipe, and
The wall thickness of the pipe is t,
The width of the engaging groove is b1,
When the width of the indentation convex part is b2,
The joining apparatus of the pipe of Claim 7 with which b1 and b2 satisfy following Formula (1), and a to-be-joined member.
0.8b1-2t ≦ b2 ≦ 1.5b1-2t (1)

[11] The depth of the engaging groove is h1,
The protrusion height of the indentation convex part is h2,
When the protrusion height of the pressing convex part is h3,
11. The joining apparatus for a pipe and a member to be joined according to 10 above, wherein h1, h2, and h3 satisfy the following expressions (2) and (3).
h1 ≦ h2 + t (2)
h3 ≦ h2 (3)

  [12] The joining device for a pipe and a member to be joined according to any one of 7 to 11 above, wherein the engaging groove portion extends in the axial direction.

  The present invention has the following effects.

  In this specification, in the state where the member to be joined is joined to the pipe, the joint strength between the pipe and the member to be joined against the circumferential load of the pipe is referred to as “torsional strength”, and the pipe against the axial load of the pipe. The bonding strength between the member and the member to be bonded is referred to as “stripping strength”.

  In the invention of [1], in the middle of expanding the insertion portion of the pipe, the engagement groove portion of the pipe is inserted into the engagement groove portion by pushing the corresponding portion of the pipe into the engagement groove portion that is elastically expanded. The corresponding part is engaged. Thereby, the joining strength of a pipe and a to-be-joined member improves. And when the pressing of the pipe insertion part with each die segment is stopped to finish the expanding process, the engaging groove part returns to its original shape due to its elastic restoring force, and accordingly, the engaging groove part is pushed into the engaging groove part. The portion corresponding to the engagement groove portion of the pipe is sandwiched and held between the inner surfaces of the engagement groove portion. Thereby, the joint strength between the pipe and the member to be joined can be further improved.

  In the invention of [2], the portion corresponding to the engagement groove portion of the pipe can be surely pushed into the engagement groove portion.

  In the invention of [3], the engaging groove can be surely expanded.

  In the invention of [4], the effects of the inventions of the above [2] and [3] are obtained, and the portion corresponding to the engagement groove portion of the pipe pushed into the engagement groove portion is between the inner side surfaces of the engagement groove portion. It is securely clamped and held. Thereby, the joining strength of a pipe and a to-be-joined member can be improved reliably.

  In the invention of [5], the portion corresponding to the engagement groove portion of the pipe can be more reliably pushed into the engagement groove portion, and the engagement groove portion can be further reliably expanded.

  In the invention of [6], since the engaging groove portion extends in the axial direction, the portion corresponding to the engaging groove portion of the pipe is pushed into the engaging groove portion, so that the engaging groove portion corresponds to the engaging groove portion. The part is engaged in the circumferential direction. Thereby, especially torsion strength (slip torque) can be improved as joint strength of a pipe and a member to be joined.

  In the inventions [7] to [12], it is possible to provide a joining device for a pipe and a member to be joined that is preferably used in the inventions [1] to [6].

  Next, an embodiment of the present invention will be described below with reference to the drawings.

  1A to 5 are diagrams illustrating an embodiment of the present invention. In FIG. 1A, 20 is a joining apparatus of the pipe and to-be-joined member which concerns on this embodiment.

  As shown in FIGS. 1A to 1C, the pipe 11 is a straight round pipe, and thus the cross-sectional shape of the pipe 11 is circular. The pipe 11 is made of a material that can be elastically deformed and plastically deformed, and is made of, for example, a metal. More specifically, the pipe 11 is made of, for example, aluminum (including an alloy thereof) and a magnesium alloy. Further, the pipe 11 is made of an extruded material, for example, a metal extruded material, and more specifically, for example, an aluminum extruded material or a magnesium alloy extruded material. Z is the central axis of the pipe 11.

  The length of the pipe 11 is set within a range of 50 to 2000 mm, for example, the outer diameter thereof is set within a range of 20 to 100 mm, and the wall thickness t is within a range of 0.5 to 5 mm, for example. Is set to However, in the present invention, each dimension of the pipe 11 is not limited to being within the above range.

  The member 15 to be joined is used, for example, as a flange or bracket attached to another member, or as a cam lobe. However, in this invention, the to-be-joined member 15 is not limited to being a flange, a bracket, or a cam lobe, and may be another member.

  The member 15 to be joined is made of an elastically deformable material, for example, a metal, and more specifically, aluminum or a magnesium alloy. The member 15 to be joined has a plate shape, and more specifically, an annular plate shape. An insertion hole 16 through which the pipe 11 is inserted is provided at the center of the member to be joined 15. The cross-sectional shape of the insertion hole 16 is a shape corresponding to the cross-sectional shape of the pipe 11, that is, a circular shape.

  Further, a short cylindrical seat portion 15 a is integrally formed at the peripheral edge portion of the insertion hole 16 of the member to be joined 15 so as to protrude from one side of the pipe 11 in the axial direction so as to surround the insertion hole 16. The seat portion 15a is formed by press-bending the peripheral edge portion of the insertion hole 16 of the member to be bonded 15 into a short cylindrical shape over the entire circumference.

  The diameter of the insertion hole 16 of the member to be joined 15 is set to be, for example, about 0.1 to 1 mm larger than the outer diameter of the pipe 11. Therefore, as shown in FIG. 1C, in a state where the pipe 11 is inserted into the insertion hole 16 of the member to be bonded 15, the inner peripheral surface 17 of the insertion hole 16 of the member to be bonded 15 and the outer peripheral surface 11 a of the pipe 11. A small gap corresponding to a dimensional difference between the diameter of the insertion hole 16 and the outer diameter of the pipe 11 is formed therebetween. The thickness of the member 15 to be joined is set within a range of 1 to 20 mm, for example. However, in this invention, each dimension of the to-be-joined member 15 is not limited to being in said range.

  Furthermore, a plurality of engaging groove portions 18 extending in the axial direction of the insertion hole 16 are formed at equal intervals in the circumferential direction on the inner peripheral surface 17 of the insertion hole 16 of the member to be joined 15. The number of the engaging groove portions 18 is eight, for example. As shown in FIG. 1C, the cross-sectional shape of the engagement groove 18 is a square shape, and the bottom surface 18 a of the engagement groove 18 is formed as a flat surface perpendicular to the radial direction of the insertion hole 16.

  As shown in FIGS. 4A to 4C, the joining structure S <b> 1 of the present embodiment has an insertion portion 12 a into the insertion hole 16 of the pipe 11 in a state where the pipe 11 is inserted into the insertion hole 16 of the member 15 to be joined. Further, the expand processing target portion 12 composed of the portions 12b and 12b in the vicinity of both sides in the axial direction is expanded (tube expansion processing), so that the member to be bonded 15 is bonded to the pipe 11 in a fixed state.

  Further, as shown in FIG. 4A, by this expanding process, in the vicinity portions 12b and 12b of the pipe 11, a bulging portion B1 having a circular arc cross section that bulges locally outward is formed. Yes. Each bulging portion B <b> 1 is formed over the entire circumference of the pipe 11 in the circumferential direction. The joined member 15 is joined to the pipe 11 so as to be sandwiched between the bulging portions B1 and B1 in the axial direction of the pipe 11, thereby improving the pull-out strength of the joined member 15 with respect to the pipe 11. Yes. That is, the bulging portion B1 is for preventing the joined member 15 from being removed from the pipe 11. Further, a bulging portion B2 that slightly bulges outward is also formed in the insertion portion 12a of the pipe 11 over the entire circumference in the circumferential direction of the pipe 11, and a member 15 to be joined is formed on the outer peripheral surface of the bulging portion B2. The inner peripheral surface 17 of the insertion hole 16 is in pressure contact (see FIG. 4).

  Further, as shown in FIGS. 4B and 4C, by this expanding process, the engagement groove portion corresponding portions 14 of the pipe 11 are pushed into the respective engagement groove portions 18 of the member to be joined 15 and are engaged in the circumferential direction. Thus, the torsional strength (slip torque) of the member 15 to be joined to the pipe 11 is improved. Further, the engagement groove portion corresponding portion 14 of the pipe 11 pushed into the engagement groove portion 18 is held between both inner side surfaces 18b, 18b of the engagement groove portion 18 so as to be joined to the pipe 11. The torsional strength of the member 15 is further improved.

  In addition, all the bulging parts B1, B1, and B2 are formed by plastically deforming the expanding target part 12 of the pipe 11 outwardly by expanding. Furthermore, the member 15 to be joined is pressed and fixed to the outer peripheral surface 11a of the pipe 11 by its own elastic restoring force (spring back force).

  Next, the configuration of the bonding apparatus 20 according to the present embodiment will be described below.

  As shown in FIGS. 1A and 1B, the joining device 20 includes an expanding die 21, a rod-shaped mandrel 28, and the like.

  The mandrel 28 has a wedge portion 28a made of tool steel or cemented carbide. The wedge portion 28 a is formed in a tapered shape at the distal end portion of the mandrel 28. The wedge portion 28a has a conical shape or a polygonal pyramid shape, and more specifically, a regular octagonal pyramid shape. Therefore, the cross-sectional shape of the wedge portion 28a is an octagonal shape (see FIG. 1B).

  Further, a mandrel driving means (not shown) is connected to the base end portion of the mandrel 28 to move the mandrel 28 in the axial direction by pressing or pulling. In the present embodiment, the mandrel driving means moves the mandrel 28 in the axial direction thereof. As this driving means, for example, a fluid pressure cylinder such as a hydraulic cylinder is used.

  The die 21 has higher strength than the pipe 11 and is made of, for example, tool steel or cemented carbide.

  As shown in FIG. 1B, the cross-sectional shape of the die 21 is a shape corresponding to the cross-sectional shape of the hollow portion 13 of the pipe 11, that is, a circular shape. More specifically, the die 21 is formed in a substantially cylindrical shape.

  In the center of the die 21, a wedge hole portion 24 corresponding to the wedge portion 28 a of the mandrel 28 is provided coaxially with the central axis Q of the die 21 and penetrating in the axial direction of the die 21. The wedge hole portion 24 has a shape corresponding to the wedge portion 28a of the mandrel 28, that is, an octagonal pyramid shape, and more specifically, a regular octagonal pyramid shape. Further, the cross-sectional shape of the wedge hole portion 24 is a shape corresponding to the cross-sectional shape of the wedge portion 28a of the mandrel 28, that is, an octagonal shape, and more specifically, a regular octagonal shape.

  Further, as shown in FIG. 1B, the die 21 is equally divided into a plurality of die segments 21a in the circumferential direction around the central axis Q, that is, a plurality of dies 21 in the circumferential direction around the wedge hole portion 28a. The die segments 21a are equally divided. In the present embodiment, the number of divisions of the die 21 is eight. Accordingly, the die 21 is configured by combining eight die segments 21a having the same shape and the same size.

  The die segment 21 a presses the expanding target portion 12 of the pipe 11 in the radially outward direction of the pipe 11 while being disposed in the hollow portion 13 of the pipe 11 to bulge locally.

  As shown in FIG. 1C, each die segment 21 a has one indentation convex portion 25 extending in the axial direction of the die 21, and two indentations that are disposed on both sides of the indentation convex portion 25 and extend in the axial direction. Convex portions 26 and 26 are provided.

  The pushing convex portion 25 is for pushing the engaging groove portion corresponding portion 14 of the pipe 11 into the engaging groove portion 18. The cross-sectional shape of the pushing convex portion 25 is a shape corresponding to the cross-sectional shape of the engaging groove portion 18, that is, a square shape. The indentation convex portion 25 extends in the axial direction of the die 21 at the circumferential intermediate portion of the outer surface 23 of the die segment 21a and locally projects in the radially outward direction of the pipe 11 (that is, the radially outward direction of the die 21). Are integrally formed. In the present specification, the outer surface 23 of the die segment 21a means a surface facing the pipe 11 side of the die segment 21a.

  The two pressing convex portions 26 and 26 have the same shape and the same size. Both pressing protrusions 26, 26 connect both side portions 19, 19 of the engagement groove portion 18 of the member to be joined 15 to the pipe 11 before the engagement groove portion corresponding portion 14 of the pipe 11 contacts the bottom surface 18 a of the engagement groove portion 18. This is for elastically expanding the engagement groove 18 by pressing the pipe 11 in the radially outward direction (see FIG. 3B). The cross-sectional shape of the pressing convex portion 26 is a square shape. And the press convex part 26 is extended in the axial direction of the die | dye 21, and is integrally formed in the circumferential direction both ends in the outer surface 23 of the die segment 21a, respectively.

  Further, as shown in FIG. 1A, the die segment 21a has two second pressing protrusions 22 and 22 that locally press the both adjacent portions 12b and 12b of the pipe 11 in the radially outward direction of the pipe 11. doing. The second pressing convex portion 22 is for forming a bulging portion B1 for retaining in the vicinity portion 12b of the pipe 11. The cross-sectional shape of the second pressing convex portion 22 is an arc shape. The second pressing protrusions 22 extend in the circumferential direction at both ends in the axial direction of the outer surface 23 of the die segment 21a, and are locally in the radially outward direction of the pipe 11 (that is, radially outward of the die 21). It protrudes and is integrally formed.

  And this joining apparatus 20 presses the both-side parts 19 and 19 of the engaging groove part 18 of the to-be-joined member 15 with the both pressing convex parts 26 and 26 of the die segment 21a through the pipe 11 in the radial outward direction of the pipe 11. The insertion portion 12a of the pipe 11 is expanded so that the engagement groove portion 18 of the pipe 11 is pushed into the engagement groove portion 18 that is elastically expanded by the pushing projection 25 of the die segment 21a. Has been made.

  Next, the joining method of the pipe 11 and the to-be-joined member 15 using this joining apparatus 20 is demonstrated below.

  First, as shown in FIGS. 1A to 1C, the pipe 11 is inserted into the insertion hole 16 of the member 15 to be joined in a loosely inserted state. This process is called “pipe insertion process”. By this step, the seat portion 15a of the member to be joined 15 is polymerized with a small gap on the outer peripheral surface 11a of the pipe 11.

  Furthermore, the die 21 is disposed at a position corresponding to the member to be joined 15 in the hollow portion 13 of the pipe 11.

  Thereafter, by inserting the wedge portion 28 a of the mandrel 28 into the wedge hole portion 24 of the die 21, the die segments 21 a of the die 21 are simultaneously moved in the radially outward direction of the pipe 11. As a result, as shown in FIGS. 3A and 3B, each die segment 21 a presses the expansion processing target portion 12 including the insertion portion 12 a of the pipe 11 and the adjacent portions 12 b and 12 b in the radially outward direction of the pipe 11. 11 expansion processing target portions 12 (that is, the insertion portion 12a and the adjacent portions 12b and 12b) are expanded. This process is called an “expanding process”. By this step, the member 15 to be joined is joined to the pipe 11 in a fixed state as shown in FIGS. 4A and 4B.

  During the expanding process, as shown in FIGS. 2A and 2B, first, the die segment 21a of the die 21 is moved radially outward, so that the engagement groove portion corresponding portion 14 of the pipe 11 is pushed into the protrusion of the die segment 21a. The portion 25 is pressed in the radially outward direction of the pipe 11 and is slightly pushed into the engaging groove portion 18.

  By continuously moving the die segment 21a, before the engaging groove portion corresponding portion 14 of the pipe 11 abuts against the bottom surface 18a of the engaging groove portion 18, both side portions 19, 19 of the engaging groove portion 18 of the member 15 to be joined are connected to the pipe. 11 and the pressing projections 26 and 26 of the die segment 21a are simultaneously pressed in the radially outward direction. Further, by continuously moving the die segment 21a, the engaging groove portion 18 of the member 15 to be joined is elastically expanded as shown in FIGS. 3A and 3B. In this way, while the engaging groove portion 18 is expanded, the engaging groove portion corresponding portion 14 of the pipe 11 is deeply pushed into the engaging groove portion 18 by the pushing convex portion 25 and closely contacts the bottom surface 18 a of the engaging groove portion 18.

  When the bulging portions B2, B1, and B1 having a predetermined bulging amount are formed in the insertion portion 12a of the pipe 11 and the adjacent portions 12b and 12b, respectively, the wedge portion 28a of the mandrel 28 is used to finish the expanding process. The die 21 is pulled out from the wedge hole 24, and the expansion target portion 12 (that is, the insertion portion 12a and the adjacent portions 12b and 12b) of the pipe 11 is stopped from being pressed by each die segment 21a. Then, as shown in FIGS. 4A to 4C, the engagement groove portion 18 returns to the original shape by the elastic restoring force of the member 15 (seat portion 15 a), and the pipe 11 pushed into the engagement groove portion 18 along with this. The engagement groove portion corresponding portion 14 is firmly held between the inner side surfaces 18b, 18b of the engagement groove portion 18. In this state, the engagement groove portion corresponding portion 14 of the pipe 11 is in close contact with the bottom surface 18a of the engagement groove portion 18 and both the inner side surfaces 18b, 18b, and a very large frictional force is applied to the engagement groove portion corresponding portion of the pipe 11. 14 is acting.

  Through the above steps, the bonded structure S1 of the present embodiment is obtained.

  For reference, FIG. 5 shows an FEM analysis diagram in a state in which the engagement groove portion 18 of the member to be joined 15 is elastically expanded in the present embodiment.

  Thus, the bonding method of this embodiment has the following advantages.

  In the middle of the expanding process, the engagement groove portion corresponding portion 14 of the pipe 11 is engaged with the engagement groove portion 18 by pushing the engagement groove portion corresponding portion 14 of the pipe 11 into the engagement groove portion 18 that is elastically expanded. The Thereby, the joining strength of the pipe 11 and the to-be-joined member 15 improves. Then, when the expansion processing target portion 12 (that is, the insertion portion 12a and the two adjacent portions 12b and 12b) of the pipe 11 is stopped from being pressed by the die segments 21a in order to end the expansion processing, the engagement groove portion 18 has its elasticity. The original shape is restored by the restoring force, and accordingly, the engaging groove portion corresponding portion 14 of the pipe 11 pushed into the engaging groove portion 18 is sandwiched and held between the inner side surfaces 18b, 18b of the engaging groove portion 18. . Thereby, the joining strength of the pipe 11 and the to-be-joined member 15 can further be improved.

  In addition, since the engaging groove portion 18 extends in the axial direction, the engaging groove portion 18 of the pipe 11 is inserted into the engaging groove portion 18 by pushing the corresponding portion 14 of the pipe 11 into the engaging groove portion 18. The corresponding portion 14 is engaged in the circumferential direction. Thereby, especially the torsional strength (slip torque) can be improved as the joining strength between the pipe 11 and the member 15 to be joined.

  Further, during the expanding process, the engaging groove portion corresponding portion 14 of the pipe 11 is pressed outwardly in the radial direction of the pipe 11 by the pressing convex portion 25 of the die segment 21 a and is pushed into the engaging groove portion 18. The groove corresponding portion 14 can be surely pushed into the engaging groove 18.

  Further, during the expanding process, before the engaging groove portion corresponding portion 14 of the pipe 11 comes into contact with the bottom surface 18 a of the engaging groove portion 18, the both side portions 19, 19 of the engaging groove portion 18 of the joined member 15 are moved to the pipe 11. Since the engaging groove 18 is elastically expanded by pressing the pressing projections 26, 26 of the die segment 21a outward in the radial direction of the pipe 11, the engaging groove 18 can be reliably expanded. it can.

  14A to 14C, when the member 115 to be joined is joined to the pipe 111 by a pipe expansion method using a pressure medium, the thickness of the pipe 111 is locally reduced as described above. However, in the joining method according to the present embodiment, such a phenomenon hardly occurs, so that the torsional strength can be further improved.

  Thus, in the joining device 20 of the present embodiment, as shown in FIG. 1C, the thickness of the pipe 11 is t, the width of the engaging groove 18 is b1, the width of the pushing protrusion 25 is b2, and the engaging groove 18 The general range of each dimension is as follows, where h1 is the depth, h2 is the protruding height of the pressing convex portion 25, and h3 is the protruding height of the pressing convex portion 26. However, in this invention, each dimension is not limited to being in the following ranges, and can be variously set according to the intended purpose and application of the pipe 11 and the member 15 to be joined.

t: 0.5 to 5 mm
b1: 2 to 20 mm
b2: 1-19mm
h1: 1-5mm
h2: 0.5 to 4.5 mm
h3: 0.1 to 4 mm

  In particular, it is desirable that b1 and b2 satisfy the following formula (1).

    0.8b1-2t ≦ b2 ≦ 1.5b1-2t (1)

  By satisfying the above expression (1), the engaging groove portion corresponding portion 14 of the pipe 11 pushed into the engaging groove portion 18 is securely held between both inner side surfaces 18b, 18b of the engaging groove portion 18. . Thereby, the joining strength of the pipe 11 and the to-be-joined member 15 can be improved reliably.

  Furthermore, it is desirable that h1, h2, and h3 satisfy the following expressions (2) and (3).

h1 ≦ h2 + t (2)
h3 ≦ h2 (3)

  By satisfying the above formulas (2) and (3), the engaging groove portion corresponding portion 14 of the pipe 11 can be pushed into the engaging groove portion 18 more reliably, and the engaging groove portion 18 can be further reliably expanded. be able to.

  In the present embodiment, the protrusion height h2 of the pressing protrusion 25 and the protrusion height h3 of the pressing protrusion 26 are both heights from the outer surface 23 of the die segment 21a. The outer surface 23 of the die segment 21 a is a circumferential surface centered on the central axis Q of the die 21. Accordingly, the central axis of curvature and the radius of curvature of the outer surface 23 correspond to the central axis Q and the radius of the die 21, respectively.

  Thus, the present invention is not limited to the above embodiment, and can be variously modified. Some of the modifications will be described below with a focus on differences from the above embodiment.

  6A to 6C show a first modification of the above embodiment. In this modified example, as shown in FIG. 6C, the bottom surface 18a of the engagement groove portion 18 of the member 15 to be joined is formed as an arc surface instead of a flat surface, and more specifically, the center axis of the insertion hole 16 is the center. Curved in an arc. Furthermore, the corners 18c and 18c between the bottom surface 18a of the engagement groove 18 and the inner side surfaces 18b and 18b are respectively rounded. By doing so, when the engagement groove 18 is expanded, the corners 18c and 18c are rounded. It is possible to prevent stress from concentrating on 18c.

  7A to 7C show a second modification of the above embodiment. In this modified example, as shown in FIG. 7C, the bottom surface 18a and the both inner side surfaces 18b, 18b of the engagement groove portion 18 of the member to be joined 15 are formed in a circular arc surface combined with each other. Furthermore, the corners 18d and 18d between the inner peripheral surface 17 of the insertion hole 16 and the inner side surfaces 18b and 18b of the engagement groove 18 are each formed round.

  FIG. 8 shows a third modification of the above embodiment. In this modification, the number of divisions of the die 21 is four. Each die segment 21a of the die 21 has two pressing convex portions 25, 25 and three pressing convex portions 26, 26, 26. The cross-sectional shape of the wedge hole portion 24 of the die 21 is circular. Further, the bottom surface of the engaging groove portion 18 of the member 15 to be joined is formed in an arc surface as in the first modification shown in FIGS.

  FIG. 9 shows a fourth modification of the above embodiment. In this modification, the number of the engaging groove portions 18 of the member to be joined 15 is four. The number of divisions of the die 21, that is, the number of die segments 21a is eight. Of the eight die segments 21a, the four die segments 21a arranged corresponding to the respective engaging groove portions 18 each have one indentation convex portion 25. The other four die segments 21a are formed so as to protrude by h3 in the radially outward direction of the pipe 11 (that is, the radially outward direction of the die 21). A portion 26 is formed. In this modified example, the engagement groove 18 has two side portions of the engagement groove 18 due to the pressing protrusions 26 and 26 of the two die segments 21a and 21a arranged on both sides of the die segment 21a having the pressing protrusion 25. By being pressed, it is expanded. Further, the bottom surface of the engaging groove portion 18 is formed in a circular arc surface in the same manner as in the first modified example shown in FIGS.

  FIG. 10 shows a fifth modification of the above embodiment. In this modification, the pipe 11 is a square pipe having a square cross section. The cross-sectional shape of the insertion hole 16 of the member to be joined 15 is a shape corresponding to the cross-sectional shape of the pipe 11, that is, a quadrangular shape. The number of the engaging groove portions 18 is eight. In other words, one engagement groove 18 is formed at each of four corners on the inner peripheral surface of the insertion hole 16 of the member to be joined 15 and an intermediate portion in the width direction of the four flat portions.

  FIG. 11 shows a sixth modification of the above embodiment. In this modification, the pipe 11 is a square pipe having a square cross section. The cross-sectional shape of the insertion hole 16 of the member to be joined 15 is a shape corresponding to the cross-sectional shape of the pipe 11, that is, a quadrangular shape. The number of the engaging groove portions 18 is four. That is, one engagement groove 18 is formed in each of the intermediate portions in the width direction of the four flat portions on the inner peripheral surface of the insertion hole 16 of the member 15 to be joined. Further, of the eight die segments 21a, the four die segments 21a arranged corresponding to the respective engaging groove portions 18 have one pressing convex portion 25 and two pressing convex portions 26, 26, respectively. And have. On the other hand, none of the other four die segments 21a has a pressing protrusion and a pressing protrusion.

  FIG. 12 shows a seventh modification of the embodiment. In this modification, the pipe 11 is a square pipe having a square cross section. The cross-sectional shape of the insertion hole 16 of the member to be joined 15 is a shape corresponding to the cross-sectional shape of the pipe 11, that is, a quadrangular shape. The number of the engaging groove portions 18 is four. That is, one engagement groove 18 is formed at each of four corners on the inner peripheral surface of the insertion hole 16 of the member 15 to be joined. Further, of the eight die segments 21a, the four die segments 21a arranged corresponding to the respective engaging groove portions 18 have one pressing convex portion 25 and two pressing convex portions 26, 26, respectively. And have. On the other hand, none of the other four die segments 21a has a pressing protrusion and a pressing protrusion.

  As mentioned above, although embodiment of this invention and some modifications were shown, this invention is not limited to these.

  In the present invention, the number of the engaging groove portions 18 is not limited to eight, but may be one or more. However, the larger the number of engaging groove portions 18 is, the more the number of the engaging groove portions 18 to be joined to the pipe 11 is. Since the torsional strength (slip torque) of the member 15 is improved, as much as possible is desirable. On the other hand, if the number of divisions of the die 21 is increased, the strength and durability of the die segment 21a is lowered. Therefore, the number of divisions of the die 21 is appropriately about 4, 6, 8, 10, 12.

  In the present invention, the engaging groove 18 may be formed to extend in the axial direction on the inner peripheral surface 17 of the insertion hole 16 of the member to be joined 15 as in the present embodiment, or may extend in the circumferential direction. It may be formed. When the engaging groove portion 18 extends in the circumferential direction, the engaging groove portion corresponding portion 14 of the pipe 11 is engaged with the engaging groove portion in the axial direction, thereby joining the pipe 11 and the member 15 to be joined. In particular, the pull-out strength of the joined member 15 with respect to the pipe 11 is improved. In this case, however, a large pressing force is required to expand the engaging groove.

  In the present invention, the pipe 11 may be a round pipe having a circular cross section, a polygonal pipe such as a quadrilateral cross section, a pentagon, a hexagon, or a deformed pipe.

  In the present invention, the material of the pipe 11 and the material of the member 15 to be joined may be the same or different from each other.

  Further, in the present invention, the expanding target portion 12 of the pipe 11 only needs to include at least the insertion portion 12a of the pipe 11, and therefore only the insertion portion 12a of the pipe 11 may be included.

  Next, specific examples and comparative examples of the present invention are shown below.

<Example>
The joined member 15 was joined to the pipe 11 in accordance with the joining method of the above embodiment shown in FIGS. The joining conditions in this case are shown below. Under these joining conditions, b1 and b2 satisfy the above formula (1), and h1, h2, and h3 satisfy the above formulas (2) and (3).

Material of pipe 11: Aluminum alloy (alloy number: 6N01)
The outer diameter of the pipe 11: 64 mm
Thickness t of pipe 11: 2 mm
Material of member 15 to be joined: aluminum alloy (alloy number: 6N01)
Thickness of the seat 15a of the member 15 to be joined: 20 mm
Diameter of insertion hole 16 of member 15 to be joined: 65 mm
Width b1 of the engaging groove 18: 10 mm
Depth of engagement groove 18 h1: 3.5 mm
Width b2 of indentation convex part 25: 6 mm
Projection height h2 of the pressing convex part 25: 3 mm
Projection height h3 of the pressing convex portion 26: 0.5 mm

<Comparative example>
The joined member 115 was joined to the pipe 111 by the pipe expansion method using the pressure medium shown in FIGS. 14A to 14C to produce a joined structure S2. The pipe 111 and the member to be joined 115 used in this case are the same as in the example. Water pressure was used as the pressure medium.

<Evaluation of slip torque>
A slip torque evaluation test was performed on the bonding structure S1 of the example and the bonding structure S2 of the comparative example. The test results are shown in FIG. As shown in the figure, the joining structure S1 of the example has a steep rise in torque and a larger maximum torque than the joining structure S2 of the comparative example. Therefore, it could be confirmed that the joining structure S1 of the example had higher torsional strength than the joining structure S2 of the comparative example.

  The present invention is used, for example, when manufacturing bumper stays, steering support beams, steering column holders, mufflers, frames, propeller shafts, suspension arms, camshafts, and other automotive parts for automobiles, or other than automobiles. As a product, it can be used for, for example, a method for joining a pipe and a member to be joined and a joining device used for the joining method, which are used when manufacturing a piping material.

FIG. 1A is a longitudinal sectional view showing a state before a predetermined portion of a pipe is expanded using a joining device for joining a pipe and a member to be joined according to an embodiment of the present invention. 1B is a cross-sectional view taken along line XX in FIG. 1A. FIG. 1C is an enlarged view of a main part of FIG. 1B. FIG. 2A is a cross-sectional view corresponding to FIG. 1B, showing a state in the middle of expanding a predetermined portion of the pipe using the joining device. FIG. 2B is an enlarged view of a main part of FIG. 2A. FIG. 3A is a cross-sectional view corresponding to FIG. 1B, showing a state in which a predetermined portion of the pipe is further expanded using the joining device. FIG. 3B is an enlarged view of a main part of FIG. 3A. FIG. 4A is a longitudinal sectional view showing a state after a predetermined portion of the pipe is expanded using the joining device. 4B is a cross-sectional view taken along line XX in FIG. 4A. FIG. 4C is an enlarged view of a main part of FIG. 4B. FIG. 5 is an FEM analysis diagram in a state in which the engagement groove portion of the member to be joined is elastically expanded in the present embodiment. FIG. 6A is a front view of a member to be joined according to a first modification of the embodiment. 6B is a cross-sectional view taken along line XX in FIG. 6A. FIG. 6C is an enlarged view of a Y portion in FIG. 6A. FIG. 7A is a front view of a member to be joined according to a second modification of the embodiment. FIG. 7B is a sectional view taken along line XX in FIG. 7A. FIG. 7C is an enlarged view of a Y portion in FIG. 7A. FIG. 8 is a diagram for explaining a third modification of the above embodiment, and is a cross-sectional view corresponding to FIG. 1B, showing a state after a predetermined portion of the pipe is expanded. FIG. 9 is a diagram for explaining a fourth modification of the embodiment, and is a cross-sectional view corresponding to FIG. 1B and showing a state after a predetermined portion of the pipe is expanded. FIG. 10 is a diagram for explaining a fifth modification of the above embodiment, and is a cross-sectional view corresponding to FIG. 1B, showing a state after a predetermined portion of the pipe is expanded. FIG. 11 is a cross-sectional view corresponding to FIG. 1B, illustrating a sixth modified example of the embodiment, showing a state after a predetermined portion of the pipe is expanded. FIG. 12 is a diagram for explaining a seventh modification of the above embodiment, and is a cross-sectional view corresponding to FIG. 1B showing a state after a predetermined portion of the pipe is expanded. FIG. 13 is a graph showing slip torque test results for the example and the comparative example. FIG. 14A is a longitudinal sectional view showing a state in the middle of joining a member to be joined to a pipe by a pipe expansion method using a pressure medium. 14B is a cross-sectional view taken along line XX in FIG. 14A. FIG. 14C is an enlarged view of a Y portion in FIG. 14B.

Explanation of symbols

S1: Joining structure 11: Pipe 12: Expand processing target part 12a: Insertion part 12b: Near part 14: Engagement groove part corresponding part 15: Joined member 16: Insertion hole 17: Inner peripheral surface 18: Engagement groove part 18a: Bottom surface 18b: Inner side surface 19, 19: Both side portions 20: Joining device 21: Die 21a: Die segment 25: Pushing convex portion 26: Pressing convex portion 28: Mandrel

Claims (8)

Using an expanding die divided into a plurality of die segments in the circumferential direction,
In a state where the pipe is inserted into the insertion hole provided in the member to be joined, the radius of the pipe is determined by inserting each of the die segments of the die disposed in the hollow portion of the pipe into the insertion hole of the pipe. By pressing outwardly, the insertion portion of the pipe is expanded, thereby joining the member to be joined to the pipe.
On the inner peripheral surface of the insertion hole of the member to be joined, an engagement groove is provided,
In the middle of expanding the insertion part of the pipe, the engagement groove part elastically expanded by pressing both side parts of the engagement groove part of the member to be joined to the outside of the pipe radius by the die segment through the pipe. , And push the corresponding part of the pipe into the engagement groove ,
Before the portion corresponding to the engagement groove portion of the pipe abuts the bottom surface of the engagement groove portion, the both sides of the engagement groove portion of the member to be joined are respectively pressed by convex portions provided on the die segment via the pipe in the radially outward direction A method for joining a pipe and a member to be joined, characterized in that the engaging groove is expanded by being pressed .   2. The method for joining a pipe and a member to be joined according to claim 1, wherein a portion corresponding to the engagement groove portion of the pipe is pressed into the engagement groove portion by pressing the portion corresponding to the engagement convex portion provided on the die segment in the radially outward direction of the pipe. The wall thickness of the pipes t,
The width of the engaging groove is b1,
When the width of the indentation convex part is b2,
The joining method of the pipe and to-be-joined member of Claim 2 with which b1 and b2 satisfy | fill following Formula (1).
0.8b1-2t ≦ b2 ≦ 1.5b1-2t (1) The method for joining a pipe and a member to be joined according to any one of claims 1 to 3 , wherein the engaging groove extends in the axial direction. Equipped with an expanding die divided into a plurality of die segments in the circumferential direction,
In a state where the pipe is inserted into the insertion hole provided in the member to be joined, the radius of the pipe is determined by inserting each of the die segments of the die disposed in the hollow portion of the pipe into the insertion hole of the pipe. By pressing outwardly, the insertion part of the pipe is expanded, thereby joining the member to be joined to the pipe, and a joining device between the pipe and the member to be joined,
On the inner peripheral surface of the insertion hole of the member to be joined, an engagement groove is provided,
By pressing both side portions of the engagement groove portion of the member to be joined to the engagement groove portion that is elastically expanded by pressing the die segment with the die segment in the radial direction of the pipe so that the engagement groove portion corresponding portion of the pipe is pushed. In addition, the pipe insertion part is to be expanded ,
The die segment is engaged by pressing both side portions of the engagement groove portion of the member to be joined to the outside of the radius of the pipe through the pipe before the corresponding portion of the engagement groove portion of the pipe contacts the bottom surface of the engagement groove portion. A joining device for a pipe and a member to be joined, characterized in that it has a pressing projection for elastically expanding the joint groove . 6. The joining device for a pipe and a member to be joined according to claim 5 , wherein the die segment has a pushing convex portion that pushes the portion corresponding to the engaging groove portion of the pipe and pushes it into the engaging groove portion. The wall thickness of the pipes t,
The width of the engaging groove is b1,
When the width of the indentation convex part is b2,
The joining apparatus of the pipe and to-be-joined member of Claim 6 with which b1 and b2 satisfy | fill following Formula (1).
0.8b1-2t ≦ b2 ≦ 1.5b1-2t (1) The joining device for a pipe and a member to be joined according to any one of claims 5 to 7 , wherein the engaging groove portion extends in the axial direction.

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