JP2006205252A - Tube end plugging method and cylinder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a cover member to be smoothly friction stir welded to a tube member without thickening the cover member. <P>SOLUTION: In the method for plugging a tube end, a cover member 11 is abutted on one end of a tube member 10 and the abutted part S is friction-stir welded by a rotary tool 6. The cover member 11 is formed like a cup and the tubular edge 14 is abutted on one end of the tube member 10. Then, a pressure receiving part 16 at one end of a mandrel 12 inserted into the tube member 10 is fitted to the tubular edge 14. The inner diameter of the tubular edge 14 is made slightly smaller than that of the tube member 11 to prevent the tube member 10 from being damaged on the inner face at the time of attaching/detaching of the mandrel 12. In addition, pressurizing force of the rotary tool 6 is received by the pressure receiving part 16 of the mandrel 12 to prevent deformation of abutted end part between the tube member 10 and the cover member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of closing a tube end portion in which a lid member is butted against one end of a tube member, and the butted portion is friction stir welded, and a cylinder device including a bottomed tube manufactured by the method.

  For example, a bottomed tube used in a monotube type hydraulic shock absorber (cylinder device) has an opening at one end of a tube body (tube member) 2 on which a piston and a free piston slide, as indicated by reference numeral 1 in FIG. Is closed by a separate end cap (lid member) 3. In such a bottomed tube 1, arc welding is generally employed for joining the end cap 3 to the tube body 2 (4 in the figure is a welded portion). However, in such a joining structure, in addition to the possibility that spatter generated during welding may enter the bottomed tube 1 as foreign matter (contamination), the tube body 2 may be thermally deformed during welding. In addition, troublesome post-processing such as cleaning work by brushing and distortion removing work is required. In the figure, reference numeral 5 denotes an attachment ring (eye) used for attachment to the vehicle body, and this attachment ring 5 is joined to the end cap 3 by arc welding (welded portion 6) separately.

  Recently, various studies have been made to adopt friction stir welding (FSW) for joining the end cap 3 to the tube body 2. In this friction stir welding, the pin part of the rotary tool is pushed into the abutting part of the two members, and the material is softened and stirred by the frictional heat generated at that time, so that the above-mentioned spatter is eliminated. In addition, since heat deformation is also suppressed, troublesome post-processing is not required.

By the way, in friction stir welding, a large pressing force is applied from the rotary tool to the abutting portion of the materials to be joined. Therefore, when the end cap 3 is simply abutted against the tube main body 2 and the friction stir welding is performed, the tube main body 2 is caused by the pressing force. There is a risk of deformation. In particular, when the tube body 2 is thin or made of an aluminum alloy, the tube body 2 is greatly deformed, and the use of friction stir welding has to be abandoned. For this reason, conventionally, as shown in FIG. 12, the end cap 3 has a stepped shape, the small-diameter convex portion 3a is fitted into the tube body 2, and the tip of the tube body 2 is butted against the step surface 3b of the end cap 3. Thus, the butt portion is friction stir welded. In this case, the pressing force of the rotary tool 6 applied from the pin portion 7 and the shoulder portion 8 of the rotary tool 6 is received by the small-diameter convex portion 3a of the end cap 3, and the deformation of the tube body 2 is prevented. In Patent Document 1, although the friction stir welding is performed between the pipe-shaped members or between the pipe-shaped member and the shaft-shaped member, one of the pipe-shaped members or the shaft-shaped member is provided with a small-diameter convex portion similar to the above. .
JP 2003-236682 A

  However, according to the measures for providing the end cap 3 with the small-diameter convex portion 3a as described above, the small-diameter convex portion 3a must be formed to a size that can backup the pressing range of the shoulder portion 8 of the rotary tool 6. Therefore, the plate thickness T of the end cap 3 becomes considerably thick, and increasing the weight of the end cap 3 inevitably increases the weight of the bottomed tube 1. In particular, the tube body 2, the end cap 3, etc. In the case where the entire bottomed tube 1 including the aluminum tube is made of aluminum, the advantages of weight reduction due to the aluminum formation are diminished.

  The present invention has been made in view of the above-mentioned problems of the prior art, and the problem is that the lid member is smoothly friction stir welded to the tubular member without increasing the plate thickness of the lid member. Another object of the present invention is to provide a cylinder end device having a bottomed tube manufactured by the closing method.

  In order to solve the above-mentioned problems, a tube end portion closing method according to the present invention is a tube end portion closing method in which a lid member is butted against one end of a tube member, and the butted portion is friction stir welded. As a cup shape, the cylindrical edge is butted against one end of the tube member, and one end of a mandrel inserted into the tube member is fitted to the cylindrical edge, and the pressure of the rotary tool is applied to the mandrel. Friction stir welding is performed while receiving pressure. In the tube end portion closing method performed in this way, the internal mandrel is subjected to pressure applied by the rotary tool, so that deformation of the tube member as well as the cover member is suppressed. It is possible to obtain a specified thickness that satisfies the required strength.

  In this method, the mandrel fitting clearance with respect to the cylindrical edge of the lid member is preferably set to 0.01 to 0.05 mm. This is because if the clearance is too small, it will be difficult to fit the mandrel into the cylindrical edge of the lid member. Conversely, if the clearance is too large, the initial deformation of the lid member and tube member will proceed due to the gap with the mandrel, and friction stirring will occur. This is because the bonding becomes unstable.

  In this method, it is desirable that the inner diameter of the cylindrical edge portion of the lid member is smaller than the inner diameter of the tube member. By doing so, the gap between the tube member and the mandrel is also enlarged, and when the mandrel is inserted into and removed from the tube member, the mandrel can be prevented from coming into contact with the tube member, and the inner surface of the tube member can be damaged. Disappears. When a bottomed tube is incorporated in a cylinder device such as the monotube type hydraulic shock absorber described above, the inner surface of the pipe member becomes a sliding surface of the piston or free piston, so that the inner surface is damaged as described above. This point is extremely important in securing the performance of the cylinder device.

  Here, as described above, when the inner diameter of the cylindrical edge portion of the lid member is set smaller than the inner diameter of the tube member, the thickness of the cylindrical edge portion of the lid member is made equal to the thickness of the tube member. Alternatively, it may be thicker than the wall thickness of the tube member, or one end portion of the tube member may be previously squeezed so that the inner diameter of the throttle portion is equal to the inner diameter of the cylindrical edge portion of the lid member.

  In order to solve the above-mentioned problems, the cylinder device according to the present invention is characterized by using a bottomed tube made of an aluminum alloy whose tube end is closed by the above-described method. In this cylinder apparatus, since the plate | board thickness of the cover member which comprises a bottomed tube is thin, the weight reduction advantage by aluminumization can be exhibited to the maximum. In this case, an attachment ring for attaching to the attached member may be friction-welded to the lid member, thereby increasing the strength of each joint and improving the strength reliability.

  According to the tube end closing method according to the present invention, the lid member can be smoothly friction stir welded to the tubular member without increasing the thickness of the lid member, so that the weight of the obtained bottomed tube is increased. Minimized. Also, if the inner diameter of the cylindrical edge of the lid member is made smaller than the inner diameter of the tube member, the inner surface of the tube member will not be damaged, so the obtained bottomed tube will be excellent in quality, Useful for cylinder devices.

  In addition, according to the cylinder device of the present invention, the advantage of weight reduction due to aluminum is maximized, and the strength of the joint is sufficient. Moreover, when the attachment ring for attaching to a to-be-attached member is friction-welded to a cover member, the intensity | strength of each junction part increases and strength reliability improves remarkably.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  1 to 4 show a tube end closing method as a first embodiment of the present invention. In the first embodiment, the bottomed tube 1 of the monotube type hydraulic shock absorber shown in FIG. 11 is to be manufactured by using friction stir welding. A tube member 10 to be provided and a lid member 11 to be provided as the end cap 3 are prepared, and a mandrel 12 that can be fitted to the lid member 11 through the tube member 10 is prepared.

  In the first embodiment, the pipe member 10 has a dimensional shape conforming to a standard required for the tube body 2 of the bottomed tube 1 to be manufactured. On the other hand, the lid member 11 has a cup shape with a shallow depth, and has a cylindrical edge portion 14 with a low seating height that abuts the tube member 10 at the peripheral edge portion of the flat plate portion 13. The cylindrical edge portion 14 of the lid member 11 is set to have a thickness equal to the thickness of the tube member 10, while its inner diameter is set to be slightly smaller than the inner diameter of the tube member 10. Therefore, in the state where the cylindrical edge portion 14 of the lid member 11 is concentrically butted against the tube member 10, there is a step δ (0. 1 to 0.5 mm) is formed (FIG. 2). Further, the height of the cylindrical edge portion 14 is set to be slightly larger than half the tip diameter of the pin portion 7 of the rotary tool 6 described later. A conical convex portion 13 a is formed at the center of the back surface of the flat plate portion 13 of the lid member 11.

  Here, the tube member 10 and the lid member 11 are made of an aluminum alloy. In this case, if the piston diameter (inner diameter of the tube main body 2) of the monotube hydraulic shock absorber to which the bottomed tube 1 is applied is 40 mm, the thickness of the tube member 10 is about 3 mm, and the lid The plate thickness (average plate thickness) of the flat plate portion 13 of the member 11 is set to about 6 mm.

  The mandrel 12 is provided with a pressure receiving portion 16 having a slightly larger diameter than the main body portion 15 at the distal end portion of the main body portion 15 having a circular cross section. The pressure receiving portion 16 of the mandrel 12 can be inserted into the tube member 10 with a predetermined clearance (0.1 to 0.5 mm) and has a slight clearance (0 in the cylindrical edge portion 14 of the lid member 11). The outer diameter is set so that it can be fitted at 0.01 to 0.05 mm). The pressure receiving portion 16 of the mandrel 12 is also the minimum necessary to back up the pressing range of the shoulder portion 8 of the rotary tool 6 in a state where the tip is in contact with the flat plate portion 13 of the lid member 11 abutted against the tube member 10. Is set to the length of

  In the first embodiment, the rotary tool 6 used for the friction stir welding is the same as that shown in FIG. 12, and a pin portion having a small diameter is connected to the tip of the stepped rod 9 via the shoulder portion 8. 7 is provided concentrically. The rotary tool 6 is configured to rotate and move in the axial direction about an axis by the rod 9 being supported by a rotation and lifting unit (not shown). The rotary tool 6 is formed of a hard material that is sufficiently harder than the aluminum alloy that is the material of the tube member 10 and the lid member 11, and has sufficient wear resistance. As an example, the tip diameter and the root diameter of the pin portion 7 of the rotary tool 6 are set to about 3 mm and about 4 mm, respectively, and the diameter (shoulder diameter) of the shoulder portion 8 is set to about 10 mm.

  In the friction stir welding, as shown in FIG. 1, the lid member 11 is concentrically butted against the tube member 10, and both are fixed in position by a predetermined thrust force, and then the mandrel 12 is inserted into the tube member 10. The pressure receiving portion 16 on the distal end side is fitted into the cylindrical edge portion 14 of the lid member 11 and is brought into contact with the flat plate portion 13 of the lid member 11. At this time, since the mandrel 12 has not only the main body portion 15 but also the pressure receiving portion 16 thereof having a diameter of about 0.2 to 1.0 mm smaller than the inner diameter of the tube member 10, the mandrel 12 does not contact the inner surface of the tube member 10. It can be inserted smoothly (without scratching).

  Similarly, as shown in FIG. 1, the rotary tool 6 has its axis C set at the standby position outside the abutting portion S of the tube member 10 and the lid member 11 with respect to the common axis of the tube member 10 and the lid member 11. Are positioned orthogonally. After completion of the preparation, the rotary tool 6 is moved from the standby position toward the abutting portion S while rotating at a predetermined rotational speed. Then, as shown in FIG. 3, the pin portion 7 is pushed into the butting portion S while rotating, and frictional heat is generated by the rotation and pushing of the pin portion 7. The material of the butt portion S is softened and agitated by this frictional heat, and the pin portion 7 is pushed in until the shoulder portion 8 of the rotary tool 6 contacts the outer surface of the cylindrical edge portion 13. At this time, the end portion of the tube member 10 on one side of the butting portion S is raised by the step δ from the cylindrical edge portion 14 of the lid member 11 (FIG. 2). It is pressed by the shoulder 8 and deformed locally and is pressed by the pressure receiving portion 16 of the mandrel 12. On the other hand, since the cylindrical edge portion 14 of the lid member 11 is substantially in contact with the pressure receiving portion 16 of the mandrel 12, the cylindrical edge portion 14 is pressed by the pressure receiving portion 16 with almost no deformation.

  Thereafter, the tube member 10, the lid member 11, and the mandrel 12 are integrally rotated at a predetermined speed in a predetermined direction while continuing the rotation of the rotary tool 6. Then, the rotary tool 6 relatively moves along the abutting portion S between the tube member 10 and the lid member 11, and the material on the front side in the moving direction of the rotary tool 6 is fluidized by frictional heat and stirred by this relative movement. Thus, the frictional joint 17 that flows into the movement trace of the pin portion 7 and extends in the circumferential direction is formed. During this time, the end of the tube member 10 on one side of the butting portion S is squeezed by the shoulder 8 of the rotary tool 6, whereby the pressure applied by the rotary tool 6 is evenly received by the pressure receiving portion 16 of the mandrel 12. As a result, the abutting end portions of the tube member 10 and the lid member 11 are formed of an aluminum alloy that is easily deformed, but are not unnecessarily deformed, whereby aluminum having a desired dimensional shape is obtained. The bottomed tube 1 (FIG. 5) made of an alloy is completed. In the first embodiment, in particular, it is not necessary to make any dimensional changes to the tube body 10 provided as the tube body 2, which is advantageous in terms of cost.

  As shown in FIG. 5, the bottomed tube 1 thus completed requires the plate thickness (average plate thickness) of the flat plate portion 13 of the lid member 11 provided as the end cap 3 in terms of strength. Since it has a prescribed plate thickness (here, about 6 mm), it does not increase in weight, and the advantage of weight reduction due to aluminum is maximized. In addition, since the friction bonding portion 17 is formed without melting, the strength is sufficient, and the obtained bottomed tube 1 has high strength reliability. In addition, on the bottom side of the bottomed tube 1, a reduced-diameter portion 19 having a drawing shape is formed by pressing the shoulder portion 8 of the rotary tool 6, but this range is outside the sliding range of the piston (free piston). Therefore, the function is not lost.

  By the way, in order to complete as a monotube type hydraulic shock absorber, it is necessary to join the attachment ring 5 to the end cap 3 of the bottomed tube 1 as described above (FIG. 11). In the first embodiment, the conical convex portion 13 a is provided on the back surface of the lid member 11 provided as the end cap 3 because the friction welding is used for joining the mounting ring 5. That is. The friction welding method includes a brake method, an inertia method, and a hybrid method using both methods. However, in any case, frictional heat is generated intensively at the conical convex portion 13a. The attachment ring 5 can be easily and reliably joined to the end cap 3. FIG. 6 shows a state after the friction welding, and the joint portion 19 between the end cap 3 and the mounting ring 5 has a healthy structure with few heat affected portions. Therefore, the bottomed tube 1 to which the mounting ring 5 is joined by using friction welding in this way, combined with the friction stir welding of the end cap 3 to the tube main body 2 described above, is extremely reliable in strength. It will be expensive. Moreover, unlike the case where arc welding is employed, there is no problem of contamination or thermal deformation, so that the obtained hydraulic shock absorber is remarkably excellent in both quality and function.

  7 and 8 show a tube end portion closing method according to the second embodiment of the present invention. In addition, since the basic form of the second embodiment is the same as that of the first embodiment, the same reference numerals are given to the same parts, and duplicate descriptions are omitted. The feature of the second embodiment is that the thickness of the cylindrical edge portion 14 is made larger than the thickness of the tube member 10 without changing the inner diameter of the cylindrical edge portion 14 of the lid member 11. The thickness is increased, and the outer peripheral surface of the cylindrical edge portion 14 and the outer peripheral surface of the tube member 10 are flush with each other (FIG. 7). In this case, the step δ is formed only inside the butted portion S between the tube member 10 and the lid member 11.

  The manner of the friction stir welding in the second embodiment is the same as that of the first embodiment, and as shown in FIG. 3, the butting portion S while rotating the pin portion 7 of the rotary tool 6 at a predetermined rotational speed. The butting portion S is pressed against the pressure receiving portion 16 of the mandrel 12 by the shoulder portion 8 of the rotary tool 6. At this time, since the outer peripheral surface of the cylindrical edge portion 14 and the outer peripheral surface of the tube member 10 are flush with each other, the pin portion 7 is smoothly pushed into the butt portion S without receiving a bending force. On the other hand, the inner side of the end portion of the tube member 10 on one side of the butting portion S floats from the pressure receiving portion 16 of the mandrel 12 by the step δ (FIG. 7). To be locally deformed and pressed by the pressure receiving portion 16 of the mandrel 12. On the other hand, since the cylindrical edge portion 14 of the lid member 11 is thick, the shoulder portion 8 of the rotary tool 6 bites into the cylindrical edge portion 14 and a step δ ′ is generated on the outer peripheral surface of the cylindrical edge portion 14. (FIG. 8). Thereafter, the tube member 10, the lid member 11, and the mandrel 12 rotate integrally, so that the rotary tool 6 relatively moves along the abutting portion S between the tube member 10 and the lid member 11, and thereby the peripheral member is rotated. A friction joint 17 extending in the direction is formed. During this time, since the pressure of the rotary tool 6 is received by the pressure receiving portion 16 of the mandrel 12, the tube member 10 and the lid member 11 are frictionally agitated without causing unnecessary deformation as in the first embodiment. Be joined. A groove-shaped diameter-reduced portion 18 ′ is formed on the bottom side of the obtained bottomed tube 1 by the biting of the shoulder portion 8 of the rotary tool 6 (FIG. 8). Since it is outside the sliding range of the piston), the function is not impaired.

  FIG. 9 and FIG. 10 show a tube end closing method as a third embodiment of the present invention. In addition, since the basic form of the third embodiment is the same as that of the first embodiment, the same reference numeral is given to the same part portion, and the duplicate description is omitted. The feature of the third embodiment is that the butt end portion of the tube member 10 is squeezed in advance and the squeezed portion 20 is butted against the cylindrical edge portion 14 of the lid member 11.

  The manner of the friction stir welding in the third embodiment is the same as that of the first embodiment, and as shown in FIG. 3, the butting portion S while rotating the pin portion 7 of the rotary tool 6 at a predetermined rotational speed. The butting portion S is pressed against the pressure receiving portion 16 of the mandrel 12 by the shoulder portion 8 of the rotary tool 6. At this time, the butted end portions of the tube member 10 and the lid member 11 are in contact with the pressure receiving portion 16 of the mandrel 12 without causing a step (FIG. 9), so that the pin portion 7 is smooth without receiving bending force. The shoulder 8 is pressed against the pressure receiving portion 16 of the mandrel 12 evenly. Thereafter, the tube member 10, the lid member 11, and the mandrel 12 rotate integrally, so that the rotary tool 6 relatively moves along the abutting portion S between the tube member 10 and the lid member 11, and thereby the peripheral member is rotated. A friction joint 17 extending in the direction is formed. During this time, since the pressure of the rotary tool 6 is received by the pressure receiving portion 16 of the mandrel 12, the tube member 10 and the lid member 11 are frictionally agitated without causing unnecessary deformation as in the first embodiment. Be joined. Further, since the butt end portions of the tube member 10 and the lid member 11 have the same thickness, the bending force does not act on the rotary tool 6, and the friction stir welding proceeds smoothly. In addition, although the diameter-reduced portion 18 ″ having a narrow shape is formed on the bottom side of the obtained bottomed tube 1 (FIG. 10), this range is outside the sliding range of the piston (free piston). Therefore, the function is not impaired.

  In each of the above-described embodiments, the present invention is applied to the manufacture of a bottomed tube of a monotube hydraulic shock absorber. However, the present invention applies not only to the bottomed tubes of various cylinder devices other than the monotube hydraulic shock absorber, Of course, it can be applied to the manufacture of bottomed tubes for various devices.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows 1st Embodiment of the block | closing method of the pipe end part which concerns on this invention, and shows the preparation state of friction stir welding. It is the A section expanded sectional view of FIG. It is sectional drawing which shows the implementation state of the friction stir welding in 1st Embodiment. FIG. 4 is an enlarged cross-sectional view of a B part in FIG. 3. It is sectional drawing which shows the structure of the bottomed tube obtained by 1st Embodiment. It is sectional drawing which shows the structure of a bottomed tube after carrying out friction welding of the attachment ring to an end cap. FIG. 7 is a cross-sectional view of a main part showing a second embodiment of the tube end closing method according to the present invention and showing a preparation state of friction stir welding. It is principal part sectional drawing which shows the implementation state of the friction stir welding in 2nd Embodiment. FIG. 7 is a cross-sectional view of a main part showing a third embodiment of the tube end closing method according to the present invention and showing a preparation state of friction stir welding. It is principal part sectional drawing which shows the implementation state of the friction stir welding in 3rd Embodiment. It is sectional drawing which shows the structure of the conventional bottomed tube used for the monotube hydraulic buffer which is the implementation object of the obstruction | occlusion method of a main pipe end part. It is sectional drawing which shows the implementation state of the conventional friction stir welding for manufacturing a bottomed tube.

Explanation of symbols

6 Rotating tool 7 Pin portion 8 Shoulder portion 10 Tube member 11 Lid member 12 Mandrel 14 Cylindrical edge portion of lid member 16 Pressure receiving portion of mandrel S Butt portion

Claims (8)

  In the tube end portion closing method in which the lid member is butted against one end of the tube member, and the butted portion is friction stir welded, the lid member is cup-shaped and its tubular edge is butted against one end of the tube member, One end of a mandrel inserted into the tubular member is fitted to the cylindrical edge, and friction stir welding is performed while the mandrel receives pressure from a rotary tool. .   The tube end portion closing method according to claim 1, wherein the fitting clearance of the mandrel with respect to the edge portion of the lid member is set to 0.01 to 0.05 mm.   The tube end portion closing method according to claim 1 or 2, wherein an inner diameter of the cylindrical edge portion of the lid member is made smaller than an inner diameter of the tube member.   The tube end portion closing method according to claim 3, wherein the thickness of the cylindrical edge portion of the lid member is made equal to the thickness of the tube member.   The tube end portion closing method according to claim 3, wherein the thickness of the cylindrical edge portion of the lid member is made thicker than the thickness of the tube member.   The method for closing a pipe end according to claim 3, wherein one end of the pipe member is squeezed in advance, and the inner diameter of the throttle part is made equal to the inner diameter of the cylindrical edge of the lid member.   A cylinder device using a bottomed tube made of an aluminum alloy, the tube end portion of which is closed by the method according to any one of claims 1 to 6. The cylinder device according to claim 7, wherein an attachment ring for attaching to the attached member is friction-welded to the lid member.

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