Plastic flow bonding structure and bonding method for rectangular members

Abstract

This invention provides a plastic flow bonding structure and bonding method for rectangular members that can achieve strong plastic flow bonding even in rectangular members. [Solution] In a plastic flow bonding structure for rectangular members in which a roughly rectangular inner member 5 is plastically flow bonded to a roughly rectangular hole 7 of a housing 3, a V-groove 10 extending continuously in the circumferential direction is formed on the outer circumference of the inner member 5, and a roughly rectangular punch 19 is pressed against the hole wall 13 of the hole 7 of the housing 3, and by pressurizing the hole wall 13, a part 20 of the hole wall 13 is plastically flowed into the V-groove 10 of the inner member 5 and bonded.

Description

Technical Field

[0001] The present invention relates to a plastic flow bonding structure and bonding method for square members.

Background Art

[0002] Patent Document 1 discloses a technique of inserting the shaft end of a metal first member into a shaft hole portion having a stepped portion provided in a metal second member and increasing the frictional force between the shaft hole portion and the shaft end by pressing the member with the lower hardness with a punch to plastically flow bond each member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique of Patent Document 1, since the shaft hole portion and the shaft end are circular and the pressing force during pressing with a punch is transmitted equally in the circumferential direction, plastic flow bonding is evenly performed in the circumferential direction. However, when each member is a square member, there is a problem that it is difficult to perform plastic flow bonding evenly in the circumferential direction. An object of the present invention is to provide a plastic flow bonding structure and bonding method for square members that can obtain strong plastic flow bonding even for square members.

Means for Solving the Problems

[0005] In a plastic flow bonding structure for plastically flow bonding a substantially square inner member to a substantially square hole portion of a housing, the present invention forms a V-groove continuously extending in the circumferential direction on the outer peripheral portion of the inner member, and presses a substantially square punch against the hole wall of the hole portion of the housing to pressurize the hole wall, thereby plastically flowing a part of the hole wall into the V-groove of the inner member for bonding.

[0006] The present invention relates to a method for plastically flow bonding a rectangular inner member to a substantially rectangular hole in a housing, wherein the inner member is provided with a V-groove extending continuously in the circumferential direction on its outer circumference, and a substantially rectangular punch is pressed against the hole wall of the hole in the housing, pressurizing the hole wall, and causing a portion of the hole wall to plastically flow into the V-groove of the inner member for bonding. [Effects of the Invention]

[0007] According to the present invention, a strong plastic flow bond can be obtained even with rectangular materials. [Brief explanation of the drawing]

[0008] [Figure 1] This is a disassembled perspective view of the cooling plate. [Figure 2] This is a cross-sectional view showing a plastic fluid bonding structure. [Figure 3] This is a cross-sectional view of section A in Figure 2. [Figure 4] This is also a cross-sectional view of section A in Figure 2. [Figure 5] This is a flowchart of the plastic flow coupling method. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings.

[0010] [First Embodiment] Figure 1 is an exploded perspective view of the cooling plate. The cooling plate 1 is constructed by joining an aluminum housing 3 with an aluminum inner member 5. Housing 3 and inner member 5 are made of the same material.

[0011] The housing 3 has a recess (hole) 7 on its upper surface. The recess 7 is rectangular (approximately square) in shape with rounded corners when viewed from above. The recessed portion 7 is provided with a hole wall 13, and the inner circumference of the hole wall 13 is a rectangle (approximately square) with rounded corners in a plan view. A stepped portion 4 is formed on the hole wall 13, and the stepped portion 4 is a rectangle (approximately square) with rounded corners in a plan view. An inlet 8 and an outlet 9 are formed at the bottom of the recessed section 7, through which cooling water enters and exits.

[0012] The inner member 5 is rectangular (approximately square) in plan view, with rounded corners at all four corners, and its outer periphery fits snugly into the hole wall 13 of the recess 7 of the housing 3. A V-groove 10 extending continuously in the circumferential direction is formed on the outer periphery of the inner member 5. The inner member 5 may also be configured such that its outer circumference fits into the hole wall 13 of the recess 7 of the housing 3 with an appropriate gap. The appropriate gap is the gap that is taken into consideration when the housing 3 and the inner member 5 undergo plastic flow bonding, as described later. That is, it includes the gap necessary to obtain a strong bond, as well as gaps due to manufacturing errors of the housing 3, inner member 5, etc.

[0013] A partition member 11 is positioned between the housing 3 and the inner member 5, forming a flow path R through which cooling water flows. Cooling water entering from the inlet 8 flows out from the outlet 9, which is separated by the partition member 11. Although not shown in the diagram, an electronic component (heating element) is placed on the upper surface of the inner member 5, and the electronic component is cooled by cooling water.

[0014] The housing 3 and the inner member 5 are plastically flow bonded together. As described later, the plastic flow bonding is performed in two stages at two locations around the entire circumference of the housing 3 and the inner member 5.

[0015] Figure 2 is a cross-sectional view showing a plastic fluid bond structure. The housing 3 is placed on the press table 12.

[0016] The housing 3 has a square recess 7 in plan view, and the hole wall 13 of the recess 7 is formed one step higher than the upper surface 3A of the housing 3. The inner peripheral portion of the hole wall 13 is square in plan view, and a stepped portion 4 that is square in plan view is formed in the middle of the hole wall 13. A restraint ring 15 is arranged on the outer peripheral portion of the hole wall 13.

[0017] An inner member 5 is arranged in the recess 7 of the housing 3. The outer peripheral portion of the inner member 5 fits into the hole wall 13 of the housing 3 without a gap, and the height of the upper surface 5A of the inner member 5 is higher than the height of the hole wall 13 of the housing 3. Note that the outer peripheral portion of the inner member 5 may fit into the hole wall 13 of the housing 3 with an appropriate gap.

[0018] An urging jig 17 is arranged above the housing 3. The urging jig 17 has a punch 19 on its lower surface. The punch 19 is substantially square with Rs at the four corners in plan view. The inner peripheral portion of the punch 19 fits into the outer peripheral portion of the inner member 5 with an appropriate gap. The appropriate gap is the gap considered when the housing 3 and the inner member 5 perform plastic flow bonding. That is, it includes the gap required to obtain a strong bonding state and the gap due to manufacturing errors of the housing 3, the inner member 5, etc.

[0019] In this embodiment, the housing 3 and the inner member 5 are plastically flow bonded at two locations, and this bonding is performed in the following two steps.

[0020] Figures 3 and 4 are cross-sectional equivalent views of part A in Figure 2. In the first step, as shown in Figure 3, an urging jig (not shown) is pressed against the inner member 5, and the inner member 5 is pressurized in the direction of arrow P. Before pressurization, the center of the V-groove 10 is at a position substantially coinciding with the upper surface height of the hole wall 13 of the recess 7.

[0021] The stepped portion 4 of the housing 3 has a shape in which the projection 4A is pointed upwards. When the inner member 5 is pressurized, the projection 4A of the stepped portion 4 is crushed and undergoes plastic flow, and the inner member 5 and the housing 3 are plastically bonded together.

[0022] After the first stage of compositional fluid bonding, the inner member 5 sinks downward by the amount by which the projection 4A of the stepped portion 4 is crushed, as shown in Figure 4. As a result, the position of the V-groove 10 moves to the position shown in Figure 4. At this position, the upper edge of the V-groove 10 is lower by a predetermined dimension than the height of the upper surface of the hole wall 13 of the recessed portion 7.

[0023] In the second stage, the hole wall 13 of the housing 3 is pressed using the punch 19 and the pressing jig 17. The combined load at this time was set to 200-250kN for a rectangle with a long side of 130mm and a short side of 60mm. When the hole wall 13 is pressurized using the punch 19, a portion 20 of the hole wall 13, shown by the dashed line, plastically flows into the V-groove 10 of the inner member 5, thereby plastically flow bonding the inner member 5 and the housing 3.

[0024] After the first and second stages, the inner member 5 and the housing 3 are plastically flow bonded, resulting in a strong bond. Furthermore, since the punch 19 is rectangular in plan view, and the inner circumference of the punch 19 fits with the outer circumference of the inner member 5 with an appropriate gap, equal pressure is applied in the circumferential direction, allowing for uniform plastic flow bonding in the circumferential direction. Note that the first stage is performed before the second stage and can be considered a preliminary stage for completely plastically flow bonding the housing 3 and the inner member 5. Performing the second stage after the first stage allows for a stronger bond between the inner member 5 and the housing 3.

[0025] [Experimental Results] The cooling plate 1, which was assembled through the first and second stages, was submerged in a water tank, and gas pressure was applied to the flow path R of the cooling plate 1 to check for gas leakage from the joint between the inner member 5 and the housing 3. The standard states that it is OK if there is no leakage when a gas pressure of 0.2 MPa is applied. In the case of a rectangular shape, it is presumed that there is more leakage, especially from the long sides, compared to a circular shape. However, in this embodiment, even when gas pressures of 0.4 MPa and 0.8 MPa were applied, there was no leakage from all sides, and it was confirmed that a strong bond was obtained.

[0026] Figure 5 is a flowchart of the plastic flow coupling method. First, the housing 3 is provided with a stepped portion 4 in the rectangular recess 7, and the inner member 5 is provided with a second stepped portion 41 (see Figure 4) on its outer circumference that engages with the stepped portion 4.

[0027] Next, the outer circumference of the inner member 5 is fitted into the rectangular recess 7 of the housing 3, and then the inner member 5 is pressurized (first step S1).

[0028] As shown in Figure 3, the stepped portion 4 is equipped with a triangular, pointed projection 4A on its upper side. In the first step S1, by applying pressure to the inner member 5, the frictional force between each stepped portion 4, 41 increases, and the housing 3 and the inner member 5 are plastically flow bonded (second step S2). At this time, the projection 4A is crushed, and the inner member 5 sinks downward by the amount that the projection 4A is crushed, as shown in Figure 4. As a result, the upper edge of the V-groove 10 becomes lower than the upper surface height of the hole wall 13 of the recess 7. The second step S2 is the first stage of plastic flow bonding.

[0029] Next, I will explain the second stage of plastic flow coupling. The inner member 5 is provided with a V-groove 10 that extends continuously in the circumferential direction on its outer circumference. The rectangular punch 19 is pressed against the hole wall 13 of the rectangular recess 7 in the housing 3 (third step S3). The inner circumference of the punch 19 fits into the outer circumference of the inner member 5.

[0030] Next, using the pressing jig 17, the hole wall 13 is pressurized by the rectangular punch 19 (fourth step S4). As a result, as shown in Figure 4, a portion 20 of the hole wall 13 is plastically flowed into the V-groove 10 of the inner member 5 (fifth step S5). Step 5, S5, is the second stage of plastic flow bonding.

[0031] [Second Embodiment] In the second embodiment, although not shown in the figures, the first stage of compositional fluid bonding is omitted because no projection 4A is formed on the stepped portion 4 of the housing 3. In other words, the inner member 5 is simply fitted into the rectangular recess 7 of the housing 3, and the inner member 5 is not subjected to any pressure. Then, only the second stage of plastic flow coupling is performed. In other words, in the second embodiment, only the second stage steps are performed, which are the same as the third step S3 to the fifth step S5 shown in Figure 5.

[0032] In this configuration, gas leak tests confirmed that no leaks occurred when a gas pressure of 0.2 MPa was applied, indicating a good coupling state. This configuration allows for the omission of the first stage, thus reducing manufacturing costs.

[0033] Furthermore, when the second stage was omitted and the test was conducted using only the compositional fluid coupling of the first stage, it was confirmed that leakage occurred, particularly from the long side, at gas pressures of approximately 0.03 MPa to 0.08 MPa, and that a sufficient coupling state could not be obtained.

[0034] In this embodiment, a roughly rectangular punch 19 is pressed against the hole wall 13 of the roughly rectangular recess 7 of the housing 3, and by applying pressure to the hole wall 13, a portion 20 of the hole wall 13 is plastically flowed into the V-groove 10 of the inner member 5.

[0035] According to this, in the case of a roughly rectangular shape, it is predicted that the strength of the bond, especially at the longer sides of the rectangular shape, will be weaker compared to the case of a circular shape. However, it was confirmed that the pressing force is applied evenly in the circumferential direction of the rectangular shape, resulting in a strong bond.

[0036] In this embodiment, the inner circumference of the roughly rectangular punch 19 is configured to fit with an appropriate gap around the outer circumference of the roughly rectangular inner member 5.

[0037] According to this, the pressure applied by the roughly rectangular punch 19 acts evenly in the circumferential direction of the roughly rectangular inner member 5, resulting in a strong bond.

[0038] In this embodiment, the inner member 5 is provided with a V-groove 10 that extends continuously in the circumferential direction on its outer circumference. A rectangular punch 19 is pressed against the hole wall 13 of the rectangular recess 7 of the housing 3, pressurizing the hole wall 13 and causing a portion 20 of the hole wall 13 to plastically flow into the V-groove 10 of the inner member 5 to bond them.

[0039] According to this, while it is predicted that the strength of the bond, especially along the longer sides of the square, will be weaker compared to the circular shape, it was confirmed that the pressing force is applied evenly in the circumferential direction of the square, resulting in a strong bond.

[0040] In this embodiment, the housing 3 is provided with a stepped portion 4 having a projection 4A in the rectangular recess 7, and in order to connect the housing 3 and the inner member 5 in advance, the inner member 5 is pressurized to crush the projection 4A and cause plastic flow.

[0041] According to this, since the first stage is performed before the second stage described above, the inner member 5 and the housing 3 are more firmly connected.

[0042] The embodiments described above are merely illustrative of one aspect of the present invention, and can be modified and applied as needed without departing from the spirit of the invention.

[0043] In the embodiments described above, the housing 3 and inner member 5 were described as being made of the same material, aluminum, but the present invention is not limited to this material. It goes without saying that the same effects can be obtained even if the housing 3 and the inner member 5 are made of different materials. In the case of different materials, it is desirable to apply pressure to the member with the lower hardness to induce plastic flow.

[0044] In the embodiments described above, the components of the cooling plate 1 were plastically flow bonded, but the present invention is not limited to the bonding of the components of the cooling plate 1. It can be applied to all bonding of rectangular materials, whether of the same or different materials. The projection 4A of the stepped portion 4 is a pointed triangular shape, but the projection 4A may also protrude in an arc shape, or a part of the stepped portion 4 may protrude in a rectangular shape. [Explanation of Symbols]

[0045] 1 Cooling plate 3 Housing 4 steps 5. Inner components 7. Recessed area (hole) 10 V groove 13 hole wall 15 Restraint Rings 17 Pressing jig 19 punches

Claims

1. In a plastic flow bonding structure for rectangular members, in which a roughly rectangular inner member is plastically flow bonded to a roughly rectangular hole in a housing, A V-groove extending continuously in the circumferential direction is formed on the outer circumference of the inner member. A roughly rectangular punch is pressed against the hole wall of the housing, and by applying pressure to the hole wall, a portion of the hole wall is plastically flowed into the V-groove of the inner member and joined together. Plastic flow bonding structure of rectangular members.

2. The inner circumference of the punch fits with the outer circumference of the inner member with an appropriate gap. The plastic flow bonding structure for rectangular members according to claim 1.

3. In a method for plastic flow bonding of rectangular members, in which a roughly rectangular inner member is plastically flow bonded to a roughly rectangular hole in a housing, The outer circumference of the inner member is provided with a V-groove that extends continuously in the circumferential direction, A roughly rectangular punch is pressed against the wall of the hole in the housing, pressurizing the wall of the hole, and a portion of the wall of the hole is plastically flowed into the V-groove of the inner member to form a bond. A method for plastic flow bonding of rectangular members.

4. The inner circumference of the punch fits with the outer circumference of the inner member with an appropriate gap. The method for plastic flow bonding of rectangular members according to claim 3.

5. The hole portion is provided with a stepped portion having a projection, and the inner member is pre-pressurized to crush the projection and cause plastic flow. A method for plastic flow bonding of rectangular members according to claim 3 or 4.

Images