JP2005081408A - Method of producing piston for swash plate type compressor with variable capacity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a piston for a swash plate type compressor with variable capacity where, in the case two piston stocks are subjected to friction stir butt welding by a probe to produce a piston, the phenomenon that a groove on detachment of the probe reduces welding strength, and disturbs the uniformity of a coating film after the welding to reduce its durability is prevented, and further, pistons with different sizes can freely be produced without depending on the outer diameter sizes of the pistons to increase productivity. <P>SOLUTION: In the production method, separately molded and temporarily bonded first and second piston stocks 23 and 26 are loaded on support rollers 33 capable of elastically being elevated and lowered by elastic springs 52, each central axis of the 23 and 26 is made coincident with the central axis of a rotationally supporting means 31 so as to rotatably be supported to the 31, a probe 41 in a welding means 40 is inserted into the welding parts of the 23 and 26 while being rotated to perform friction stir butt welding as the 31 is rotated, and, the 41 is moved to a prescribed position far from the welding parts and is thereafter detached. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a piston for a variable capacity swash plate compressor (Swash Plate Type Compressor With Variable Capacity), and more specifically, two piston materials having a circular cross section are manufactured by friction stir welding. In this case, by preventing the formation of grooves in the welded part of the piston material, the durability of the welded part is improved, and the piston can be freely manufactured by size regardless of the outer diameter size of the piston. The present invention relates to a method for manufacturing a piston for a variable displacement compressor.

  In general, a variable capacity swash plate compressor among compressors constituting a cooling device for an automobile or the like includes a rear housing before forming a sealed space including a crank chamber, a suction chamber, and a discharge chamber; A cylinder block having a plurality of cylinder bores arranged in the circumferential direction and provided between the front and rear housings; a drive shaft rotatably supported at the center of the cylinder block; and provided on each of the drive shafts A lug plate and a swash plate; a plurality of pistons coupled with a shoe around the swash plate; a valve unit provided between the cylinder block and the rear housing; and transfer of the piston A control valve for adjusting the amount; and a swash plate support that is elastically provided between the swash plates and supports the swash plate at a minimum inclination angle when the lug plate is not rotating. It is made from the use spring.

In such a variable capacity swash plate compressor, the weight of the piston becomes an inertial force that hinders the reciprocating motion of the piston in the refrigerant compression process, which causes a reduction in compression efficiency.
In order to improve this, the piston is manufactured from a light material, and recently, a method of manufacturing a piston that is further reduced in weight by forming a hollow inside the piston has been pursued.

  Conventionally, when manufacturing such a hollow piston, a first piston material having a bridge with a shoe pocket on which a shoe connecting the piston and the swash plate is seated on the inside, and a second piston having a hollow portion After forming the materials separately, machining them and temporarily joining them together, the fitting surfaces of the two materials (first piston material and second piston material) are welded and fixed together with an electron beam in a vacuum state. , Manufactured through stages.

However, according to the manufacturing method of the hollow piston as described above, it is necessary to precisely process the fitting surface, the welding time of the fitting surface is relatively long, and the two materials are assembled and assembled. Since the processing procedure is complicated, there is a problem that the productivity is greatly reduced and the defect occurrence rate is very high.
Further, in the electron beam welding process, fine holes and the like are generated in the structure of the two materials, so that the durability of the piston is deteriorated, and refrigerant and oil penetrate into the hollow portion through the fine holes and the like. In addition, there is a problem that the refrigerant and oil become insufficient, and particularly for the electron beam welding, the region where the two materials are welded must be maintained at a high vacuum, so that the maintenance cost is low. There was a problem that the production cost increased due to the increase.

  In order to solve the above problems, conventionally, as disclosed in European Patent Publication No. 0,959,227, after forming the two materials, respectively, a fitting surface parallel to the tip surface of the two materials The friction welding method was adopted in which the hollow portion is formed by the generated frictional heat by rotating the two mating surfaces in a standby state with the two fitting surfaces being in contact with each other.

  However, the temperature distribution of the mating surface becomes non-uniform due to minute differences in flatness of the mating surface, and it is difficult to maintain the welding strength of the mating surface uniform. Also, due to the difference in relative rotational speeds at the joint surfaces of the two materials, the closer to the outer peripheral surface of the piston, the higher the temperature, so that the welding strength increases. However, the outer peripheral surface layer is removed by machining after welding, so the remaining The weld strength of the part which becomes is relatively small.

  Meanwhile, US Pat. No. 5,460,317 discloses a friction stir welding method different from the friction welding method. In the friction stir welding method, a probe made of a material harder than the two materials is applied to the surfaces of the two materials that are continuous or substantially continuous. The two materials are welded by forming a firing zone in the material around the probe and solidifying it by frictional heat generated by causing a relative periodic motion between the materials at the same time. Is.

  Such a friction stir welding method is advantageous in that there is no limitation on the metal material of the two materials and there are few defects such as deformation due to thermal distortion. However, after friction welding, a friction welding site between the two materials is detected by a probe. There was a problem that grooves were formed.

For example, as shown in FIG. 13, when the compressor piston 20 is manufactured using the friction stir welding method, a groove is formed in a part of the welded portion 29 a of the first piston material 23 and the second piston material 24 having the bridge 21. (Probe separation hole) 28a was formed.
As a result, after the friction welding, a coating film having a uniform thickness cannot be formed during the coating process, which is a post-treatment process, and the durability of the welded portion may be reduced.

  That is, the second piston material 24 of the piston 20 used in the variable capacity swash plate compressor is rubbed with the inner surface of the cylinder bore during the reciprocating motion of the piston. In order to ensure wear resistance and airtightness, a post-processing step is performed in which a uniform coating film is formed on the outer peripheral surface of the second piston material 24 including the welded portion and then polished. Therefore, as described above, when the groove 28a is formed at the welded portion between the two materials, the coating liquid enters the groove during the coating process, and when the baking treatment is performed in this state, the groove 28a is raised at the position of the groove 28a. As a result, the thickness of the coating film becomes non-uniform and is subjected to eccentric processing during the polishing process, thereby causing a problem that the durability is greatly reduced.

  Further, according to the friction stir welding method, when the probe is inserted into the welded portion of the two materials, there is a risk that the material may bend and deform due to pressure, so a piston for a compressor that has a precise outer diameter is manufactured. There was a problem that it was difficult to do.

  In order to prevent the occurrence of such bending deformation, Japanese Patent Laid-Open No. 11-156560 discloses an outer peripheral surface of the two materials on the opposite side of the probe with respect to the two materials, that is, on the lower side of the two materials. There is disclosed a friction stir welding apparatus in which bending of the two materials can be prevented by providing at least one bending preventing support roller in contact with the pressure and supporting the pressure when the probe is inserted by the support roller.

  However, according to the friction stir welding apparatus, the support roller for bending prevention is provided in a fixed state so as to support the lower side of the two materials. Therefore, the two materials are placed on the fixed support roller. In order to rotate, the two materials must have an outer diameter size that can be accurately aligned with the central axis of the rotating means.

  As a result, the conventional friction stir welding apparatus can only manufacture pistons having the same outer diameter size, so that in order to manufacture pistons having different outer diameter sizes, the outer diameter sizes should be matched. However, there is a need to change the device each time, and to manufacture it separately, which causes a problem of increasing the manufacturing cost.

US Pat. No. 6,568,914 US Pat. No. 5,460,317 European Patent Publication No. 0,959,227 Japanese Published Patent No. 11-156560

  Accordingly, an object of the present invention is to form a groove at the welded portion of the piston material when the piston is manufactured by friction stir welding of two piston materials having a circular cross section in order to solve the conventional problems. To provide a method for manufacturing a piston for a variable capacity compressor that can prevent a decrease in durability of the welded part during a coating process and a polishing process, which are post-processing steps after friction stir welding. is there.

  Another object of the present invention is to provide a method for manufacturing a piston for a variable displacement compressor, which can freely manufacture pistons having different sizes regardless of the outer diameter size of the piston.

  The manufacturing method of a piston for a variable displacement compressor according to the present invention, which has been made to solve the above-mentioned problems, relates to claim 1 and includes a bridge (21) and a first extending in the longitudinal direction from the bridge (21). A first piston material molding step of molding a first piston material (23) having a coupling portion (22); and a second coupling portion coupled with the first coupling portion (22) of the first piston material (23). 24) and a second piston material forming step for forming a second piston material (26) which is combined with the first piston material (23) to form a hollow portion (25); and the first and second piston materials (23) and (26) a support stage in which the first and second support means (31a) and (31b) are rotatably supported from the temporarily coupled state; and the first and second coupling parts (22), (24) on the welding site side The contact means (40) is advanced while being rotated, and the first support means (31a) and / or the second support means (31b) are rotated at a predetermined number of revolutions in a state where the welding means enters and is in close contact with the welding site. A welding stage in which friction stir welding is performed by the generated frictional heat; and a welding means position shift that moves the welding means (40) that has entered the welding site from the welding site to a predetermined position after the welding of the welding site is completed. And a welding means separating step of detaching the welding means (40) from the welding site.

  Preferably, according to claim 2, a first piston material forming step of forming a first piston material (23) having a bridge (21) and a first coupling part (22) protruding from the bridge (21); The first piston material (23) has a second coupling part (24) coupled to the first coupling part (22) and is coupled to the first piston material (23) to form a hollow part (25). A second piston material forming step for forming a two-piston material (26); and the first and second piston materials (23), (26) are temporarily joined, and the temporarily-coupled first and second piston materials ( 23) and (26) are elastically supported on a support roller (33) provided elastically by an elastic spring (52), and then the first and second piston materials (23) and (26). The center axis positions of the first and second A central axis alignment step for matching the central axis positions of the support means (31a) and (31b); and after the alignment of the central axis, the first and second piston materials (23) and (26) can be rotated. And a supporting stage for supporting the first and second support means (31a) and (31b) by rotating the welding means (40) to the welding site side of the first and second coupling portions (22) and (24). The first support means (31a) and / or the second support means (31b) are rotated at a predetermined rotational speed in a state in which the first support means (31a) and / or the second support means (31b) are rotated in a state where the welding part is advanced and brought into close contact with the welding site. A welding stage for stirring welding; a welding means position moving stage for moving the welding means (40) that has entered the welding site after completion of welding at the welding site to a predetermined position from the welding site; 40) Characterized in that it comprises a; welding means separating step separates from serial welded part and.

  Preferably, according to claim 3, the welding step is performed such that the first and second piston materials (23) and (26) are 1 by the first support means (31 a) and / or the second support means (31 b). It is performed by rotating.

  Preferably, according to claim 4, in the welding means position moving step, the table (36) is moved by a predetermined distance in the piston axial direction.

  Preferably, according to claim 5, the welding means (40) is moved from the welded portion to the bridge (21) portion of the first piston material (23) by the movement of the table (36). And

  Preferably, according to claim 6, the support roller (33) is connected to the lower side of a support member (34) supporting both ends of the support roller (33) and is elastically supported by an elastic spring (52). It is characterized by being lifted up and down by the lifted member (53).

  Preferably, according to claim 7, the center axis alignment is performed on the support roller (33) by a center axis position adjusting guide member (60) provided on the upper side of the second support means (31b). Among the first and second piston materials (23) and (26) elastically supported by the first and second piston materials, the upper surface of the second piston material (26) is pressed.

  Preferably, according to claim 8, after the step of supporting the first and second piston materials, an elevating member (53) elastically provided by an elastic spring (52) below the support roller (33). The fixing means (70) provided below the lower end is advanced to the lower end side of the elevating member (53) by the driving means (77) so that the lower end is fixed. The method further includes a support roller fixing step of fixing the support roller (33) by bringing the upper end portion into contact with the lower end portion of the elevating member (53).

  According to the present invention, the probe is inserted into a portion to be welded of the two piston materials supported by the rotation support means to perform friction stir welding, and after the rotation support means is moved by a predetermined distance, the probe , And forming a groove due to the probe detachment in the uncoated region, not in the welded region that is the region to be coated, not only increases the welding strength in the welded region, but also after the welding process. Since a uniform coating film can be formed in the coating region of the piston during the coating process, which is a processing step, the durability of the piston can be enhanced as a whole.

  Further, according to the present invention, the support roller for maintaining the temporarily connected state of the two piston materials is configured to be moved up and down elastically, so that the two pistons can be moved regardless of the outer diameter size of the piston. The operation of matching the center axis position of the piston material with the center axis position of the rotation support means is easy, whereby pistons of different sizes can be manufactured freely.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram schematically showing the structure of a variable displacement swash plate compressor to which a piston manufactured by applying a manufacturing method according to the present invention is to be mounted.

  The compressor includes a rear housing 11 and 12 and a plurality of cylinder bores 13a arranged in a circumferential direction before forming a closed space such as a crank chamber 11a, a suction chamber 12a, and a discharge chamber 12b. A cylinder block 13 provided between the front and rear housings 11 and 12; a drive shaft 14 rotatably supported at the center of the cylinder block 13 and provided with a lug plate 15; one side of the lug plate 15; The swash plate 16 is hinged and the inclination angle is changed in accordance with the cooling load; and the shoe 17 provided on the outer periphery of the swash plate 16, and each bore of the cylinder block 13 is rotated by the rotation of the swash plate 16. It consists of a number of pistons 20 that reciprocate within 13a.

  The piston 20 used in the variable displacement swash plate compressor configured as described above has a hollow portion formed therein to reduce the inertial force during reciprocating transfer, that is, its weight.

  2 and 7 are a perspective view and a cross-sectional view showing the structure of such a piston in detail. The piston 20 is a shoe on which a shoe for connecting the piston to the swash plate is seated. A first piston material 23 comprising a bridge 21 provided with a pocket, and a first coupling part (22) extending in the longitudinal direction from the bridge 21, and a first coupling part of the first piston material 23 are fitted. A second piston material 26 having a second coupling portion (24) extended in the longitudinal direction on one side and forming a hollow portion 25 sealed by fitting with the first piston material 23, It is configured.

  Furthermore, support portions 22a and 24a having steps so as to fit and support each other are provided at one end of the first coupling portion of the first piston material 23 and the second coupling portion of the second piston material 26. It is formed.

  In general, the piston 20 having such a structure is obtained by molding the first piston material 23 and the second piston material 26 separately, then machining them and temporarily joining them, Friction agitation in which welding is performed by the generated frictional heat while rotating the first and second piston materials 23 and 26 in a state where the welding means enters and is in close contact with the parts to be welded of the second piston materials 23 and 26. Manufactured by welding method.

  FIG. 3 shows an apparatus for performing the friction stir welding method for a piston for a variable capacity swash plate compressor as described above.

  As shown in FIG. 3, the friction stir welding apparatus for the piston has a table 36 so as to rotatably support the first and second piston materials 23 and 26 that are temporarily joined in a state in which the central axes are aligned with each other. The rotation support means 31 fixedly installed on the upper surface of the first and second piston materials 23 and 26 supported by the rotation support means 31, the parts to be welded, that is, the first and second coupling portions. It comprises welding means 40 for welding by frictional heat in a state of entering and closely contacting the butted portion on the outer peripheral side of the fitting portion of the support portions 22a and 24a.

  The rotation support means 31 includes first and second support means 31a and 31b that rotatably support one side surfaces of the first and second piston materials 23 and 26, respectively, and the first and second support means 31a, Any of 31b, for example, driving means (not shown) for driving the first support means 31a is included. Of course, the drive means can arbitrarily adjust the rotational speed of the first and second support means 31a and 31b. Further, one of the first and second support means 31a and 31b, for example, the second support means 31b is provided with a hydraulic cylinder 32 at the end thereof so as to be able to move forward and backward in the piston axial direction.

  The welding means 40 is moved by a servo transfer device (not shown) so as to be moved up and down to the welded portions of the temporarily coupled first and second piston materials 23 and 26 supported by the rotation support means 31. A pin-shaped probe 41 is provided at the tip so that the welding part can be welded by generating frictional heat and being welded by being rotated by a spindle motor (not shown).

  In particular, between the first and second support means 31a and 31b, the first and second piston materials 23 and 26 supported by the first and second support means 31a and 31b are in close contact with each other, A support roller 33 is provided so as to reliably maintain the temporarily connected state of the first and second piston materials 23 and 26.

  As shown in FIG. 3, the two support rollers 33 are adjacent to each other, and are provided on an upper portion of a fixed base 35 fixed to the upper surface of the table 36 so that the cylindrical piston 20 can be stably supported. Two support members 34 are rotatably provided.

  When the piston 20 having an outer diameter of, for example, approximately 30 mm, that is, the first and second piston materials 23 and 26 that are temporarily joined is loaded onto the support roller 33 having such a structure, the piston 20 The central axis of the rotation support means 31 and the central axis of the rotation support means 31 are in a state of being coincident with each other.

  From this state, the second support means 31b of the rotation support means 31 is moved to the first support means 31a side by the hydraulic cylinder 32, while the central portions of both ends of the first and second support means 31a and 31b are moved. The protrusions (not shown) formed on the first and second piston materials 23 and 26 are accurately inserted into the center grooves 27 formed on both ends, so that the piston 20 is It is supported by the second support means 31a, 31b.

  In this manner, the first and second piston materials 23 and 26 are supported by the rotation support means 31, and the probe 41 is inserted and added to the welded portion of the first and second piston materials 23 and 26. The bending of the first and second piston materials 23 and 26 can be prevented by the pressure and the supporting force by the support roller 33 acting in opposite directions.

  In general, when a piston 20 having an outer diameter larger than the outer diameter of the piston 20 is loaded on the support roller 33, the center axis position of the piston 20 and the center axis position of the rotation support means 31 are The rotation support means 31 cannot support the piston 20 because they do not coincide with each other.

  However, in this embodiment, the support roller 33 is configured to be able to move up and down elastically, so that the center axis of any piston 20 can be reliably aligned with the center axis of the rotation support means 31 regardless of the outer diameter size. Can do.

  That is, as shown in FIGS. 4 and 5, a vertical through hole 51 is formed in the fixed base 35 below the support member 34 that further supports the support roller 33, and the support member 34 is placed in the vertical through hole 51. A configuration in which an elevating member 53 protruding vertically from the lower surface and elastically supported by the elastic spring 52 is accommodated can be employed.

  The elevating member 53 is connected to the upper elevating member 53a connected to the lower surface of the support member 34 and the lower surface of the second piston material 53a, and has an outer diameter smaller than the outer diameter of the upper elevating member 53a. The lower elevating member 53b has a structure in which the end is inclined. The lower part of the lower elevating member 53b protrudes out of the passage through a passage narrower than the vertical through hole 51.

  Further, a concave groove 54 is formed on the lower outer peripheral surface of the upper elevating member 53a, and the elastic spring 52 is fitted on the outer peripheral surface of the lower elevating member 53b. At the lower end of the upper elevating member 53a, the end of the elastic spring 52 is supported by a locking jaw 55 formed on the boundary surface between the vertical through hole 51 and the passage.

  As a result, when the piston 20 having a large outer diameter is loaded onto the support roller 33, the load force of the piston 20 is applied to the support roller 33, and the elevating member provided below the support member 34. An adjustment can be made so that the central axis position of the piston 20 coincides with the central axis position of the rotation support means 31 while being elastically raised and lowered by 53.

  Referring to FIG. 3, in order to reliably adjust the position of the central axis, one of the rotation support means 31, for example, above the second support means 31b, is elastic on the support roller 33. A central axis position adjusting guide member 60 is provided for gripping the upper surface of the piston 20 that is moved up and down while being pressurized.

  As shown in FIG. 6, the guide member 60 has a fastening piece 60a having fastening holes 60a1 and 60a2 so as to be detachably coupled to the upper side of the second support means 31b, and is bent from the fastening piece 60a in the longitudinal direction. An extended portion 60b extended from the extended portion 60b, an inclined portion 60c inclined at a predetermined inclination angle from the extended portion 60b, and a distal end outer peripheral surface of the second piston material 26 that is bent vertically from the inclined portion 60c. The gripping portion 60d has an arc shape so that it can be gripped.

  Thus, the piston 20 can be supported by the rotation support means 31 after the guide member 60 reliably matches the center axis position of the piston 20 and the center axis position of the rotation support means 31.

  Thus, after the piston 20 is supported by the rotation support means 31, it is necessary to fix the support roller 33 so as not to move up and down any further.

Referring to FIGS. 4 and 5, for this purpose, a fixing means 70 is provided below the lower elevating member 53 b of the elevating member 53 to stop the elevating action of the elevating member 53.
The fixing means 70 has a tip end inclined according to the shape of the lower end of the lower elevating member 53 b, and a horizontal through hole 71 is formed inside. The elastic spring 72 is elastic in the horizontal through hole 71. Wedge-type fixing member 74 provided with a moving member 73 supported in a fixed manner, and a connecting member fastened by a bolt 75 to the end of the moving member 73 protruding outside the horizontal through hole 71 of the wedge-type fixing member 74 76.

  Further, at the end of the connecting member 76, the wedge-shaped fixing member can be moved by the moved connecting member 76 by moving the connecting member 76 forward and backward. A cylinder 77 is connected. The bolt 78 fastens the connecting member 76 and the air cylinder 77.

In the fixing means 70 having such a structure, when the air cylinder 77 is actuated first, the connecting member 76 moves back and forth in the direction of the arrow by the air pressure, and the wedge-type fixing member 74 connected to the connecting member 76 moves back and forth. To come.
At this time, since the moving member 73 provided in the horizontal through hole 71 of the wedge-type fixing member 74 is buffered by the elastic force of the elastic spring 72, the wedge-type fixing member 74 gradually moves.

  FIG. 4 shows a case where the wedge-shaped fixing member 74 is retracted to the terminal end of the lower elevating member 53 b of the elevating member 53. In this case, since the end of the lower elevating member 53b and the tip of the wedge-shaped fixing member 74 are separated, the support roller 33 is elastic by the elevating member in the range H shown in FIG. Go up and down.

  As shown in FIG. 5, when the wedge-type fixing member 74 advances, the inclined tip of the wedge-type fixing member 74 comes into contact with the inclined lower end of the lower elevating member 53b, and the elevating member 53 No more descent.

  On the other hand, the table 36 provided on the lower side of the rotation support means 31 is connected by a transfer means 38 so that it can be moved left and right in the range of a predetermined section in the direction of the piston axis by a servo motor 37 as shown in FIG. .

  Accordingly, when the servo motor 37 is driven in a state where the probe 41 has entered the welded portion of the piston 20 supported by the rotation support means 31, the table 36 moves within a predetermined section.

  Hereinafter, a process of manufacturing the piston 20 by the friction stir welding apparatus for a piston according to the present invention configured as described above will be described with reference to FIGS.

  First, a first piston material molding step for molding a first piston material 23 having a bridge 21 and a first coupling part (22) extended from the bridge 21, and a second coupling to be coupled to the first coupling part. A second piston material forming step is performed in which a second piston material 26 that has a portion (24) and is connected to the first piston material 23 to form a hollow portion is formed.

  The molding of the first and second piston materials 23 and 26 as described above can be performed by forging. Further, the first and second coupling parts (22, 24) are processed to have support parts 22a, 24a having a step so that they can be precisely fitted and maintained in the coupled state. Further steps can be performed.

  Thus, when the molding steps of the first and second piston materials are completed, as shown in FIG. 7, the support portions 22a and 24a are fitted, and the first and second coupling portions (22 and 24) are fitted. A temporary joining step is performed.

  Thereafter, the first and second piston materials 23 and 26 that have been temporarily joined are loaded onto the support roller 33 between the first and second support means 31a and 31b, which are the rotation support means 31, and then the A support stage is performed in which the first and second piston materials 23 and 26 are supported by the first and second support means 31a and 31b.

  For this purpose, first, when the second support means 31b is advanced by the hydraulic cylinder 32 toward the second piston material 26 loaded on the support roller 33, it is formed at the end center of the second support means 31b. The projected portion is inserted into a center groove 27 processed at the end of the second piston material 26.

  In this state, when the first support means 31a is continuously advanced, a center groove 27 formed at the terminal end of the first piston material 23 temporarily joined to the second piston material 26 becomes the first support means. The first and second piston materials 23 and 26 are firmly supported by the first and second support means 31a and 31b in contact with the protrusions formed at the end of 31a.

  At this time, if the outer diameter of the first and second piston materials 23 and 26 loaded on the support roller 33 that moves up and down is approximately 30 mm, the first and second piston materials 23 and 26 and the first 1. Since the central axes of the first and second support means 31a and 31b coincide with each other, the first and second piston materials 23 and 26 are formed on the upper side of the second support means 31b and the guide member 60 for adjusting the central axis position. Is almost unaffected.

However, when the outer diameters of the first and second piston materials 23 and 26 are larger than the outer diameter, the central axes do not coincide with each other, so that the alignment process of the central axes is performed.
In this positioning step, when the guide member 60 pushes the upper side of the second piston material 26 temporarily joined to the first piston material 23 and the support roller 33 moves downward, the second piston material 26 moves. The center axis position 26 is matched with the center axis position of the second support means 31b.

  At this time, the guide member 60 can be replaced with one that matches the outer diameter of the piston 20 so that the upper belt of the second piston material 26 is gripped and pressed.

  When the alignment of the central axes is completed, the support roller 33 cannot be lowered any further by advancing the wedge-shaped fixing member 74 of the fixing means 70 provided below the support roller 33 by the air cylinder 77. A support roller fixing step of fixing the support roller 33 is performed.

  Therefore, as shown in FIG. 8, the welding means 40 is rotated downward by a spindle motor (not shown), and then the probe 41 of the welding means 40 is moved to the first and second pistons as shown in FIG. The materials 23 and 26 are welded to the butted portions on the outer peripheral side of the fitting portions of the support portions 22a and 24a of the first and second coupling portions.

  From this state, the first support means 31a is rotated once, the probe 41 that has entered is moved along the abutting portion on the outer peripheral side, and the first and second couplings are caused by frictional heat generated by frictional contact at that time. The friction stir welding step of welding the support portions 22a and 24a of the portion is performed.

  Thus, when welding of the support portions 22a and 24a of the first and second coupling portions is completed by one rotation of the rotation support means, the probe 41 that has entered is welded to the welded portion (the abutting portion on the outer peripheral side that is melted) The welding means separating step is released.

  At that time, when the probe 41 is immediately detached from the welded portion as in the prior art, a groove (probe removal hole) 28a is formed in a part of the welded portion 29a as shown in FIG. Therefore, after the welding, in the coating process, which is a post-treatment process, the coating liquid is accumulated in the groove 28a, and when fired and polished in this state, the thickness of the coating film becomes non-uniform, and the durability of the welded part Will be damaged.

  Therefore, referring to FIG. 10, according to the present invention, in order to prevent this, the position of the groove (probe release hole) must first be moved from the welding site to a position that is an uncoated region before the welding means separating step. I must. Therefore, the servo motor 37 is driven to move the table 36 provided below the rotation support means 31 in the piston axial direction.

  In order to move the position of the probe 41 from the welding site to a position that is an uncoated region, the welding means 40 may be moved instead of the table 36.

  If the position of the probe 41 is moved to the bridge 21 portion of the first piston material 23 which is an uncoated region by the moving step, the welding means 40 is moved to the probe 41 by the spindle motor as shown in FIG. The welding means separation step is performed in which the first piston material 23 is detached from the bridge portion 21 and returned to the original position.

  FIG. 12 shows the structure of the piston 20 manufactured by the above-described method. After the friction welding, a groove (probe detachment hole) 28 by the probe 41 of the welding means 40 is formed on the first piston material 23. It can be seen that the bridge 21 is formed.

  Reference numeral 29 indicates a trace of the probe 41 of the welding means 40 that has passed through the welded portions of the first and second piston materials and the bridge 21.

  As described above, the preferred embodiments of the present invention have been described. However, the gist of the present invention is not limited thereto, and those skilled in the art can make various modifications and applications without departing from the spirit of the present invention. is there. Accordingly, the true technical protection scope of the present invention is defined by the technical spirit of the appended claims.

  INDUSTRIAL APPLICABILITY The present invention is particularly suitable for the manufacture of a piston for a compressor used in a vehicle air conditioner, and the friction stir welding method capable of obtaining a uniform welding strength economically and efficiently is substantially independent of the diameter of the piston. Since a uniform coating film can be obtained in the post-treatment coating, a highly durable piston can be manufactured at low cost.

1 is a schematic sectional view of a variable capacity swash plate compressor employing a piston according to the present invention. The perspective view of the piston by this invention. The front view which showed roughly the friction stir welding apparatus of the piston by this invention. FIG. 4 is a side sectional view schematically showing an elastic structure of a support roller in FIG. 3. FIG. 4 is a side sectional view schematically showing an elastic structure of a support roller in FIG. 3. The perspective view of the guide member in FIG. 1 is a cross-sectional view of a piston according to the present invention. The schematic sectional drawing which showed the manufacturing process of the piston by this invention. The schematic sectional drawing which showed the manufacturing process of the piston by this invention. The schematic sectional drawing which showed the manufacturing process of the piston by this invention. The schematic sectional drawing which showed the manufacturing process of the piston by this invention. The drawing which showed the state by which the piston by this invention was welded. The drawing which showed the state by which the piston was welded by the prior art.

Explanation of symbols

20: Piston 21: Bridge 22: First coupling portion 22a: Support portion of the first coupling portion 23: First piston material 24: Second coupling portion 24a: Support portion of the second coupling portion 25: Hollow portion 26: Second Piston material 27: Center groove 28, 28a: Groove 29, 29a: Welded part 31: Rotation support means 31a: First support means 31b: Second support means 32: Hydraulic cylinder 33: Support roller 34: Support member 35: Fixing base 36: Table 37: Servo motor 38: Transfer means 40: Welding means 41: Probe 51: Vertical through hole 52, 72: Elastic spring 53: Elevating member 53a: Upper elevating member 53b: Lower elevating member 54: Concave groove 55 : Locking jaw 60: guide member 70: fixing means 71: horizontal through hole 73: moving member 74: wedge-shaped fixing member 75, 78: bolt G 76: Connecting member 77: Driving means (air cylinder)

Claims (8)

A first piston material forming step of forming a first piston material (23) having a bridge (21) and a first coupling portion (22) extending longitudinally from the bridge (21);
The first piston material (23) has a second coupling part (24) coupled to the first coupling part (22) and is coupled to the first piston material (23) to form a hollow part (25). A second piston material molding stage for molding a two-piston material (26);
A support stage in which the first and second piston materials (23), (26) are supported by the first and second support means (31a), (31b) so as to be rotatable from the temporarily coupled state;
In a state where the welding means (40) is rotated and advanced toward the welding site side of the first and second coupling portions (22) and (24), and enters the welding site and is in close contact with the first supporting means (31a). And / or a welding stage in which friction stir welding is performed by frictional heat generated by rotating the second support means (31b) at a predetermined rotational speed;
A welding means position moving stage for moving the welding means (40) that has entered the welding site from the welding site to a predetermined position after the welding of the welding site is completed;
A welding means separating step of detaching the welding means (40) from the welding site;
A manufacturing method of a piston for a variable displacement swash plate compressor. A first piston material forming step of forming a first piston material (23) having a bridge (21) and a first coupling portion (22) protruding from the bridge (21);
The first piston material (23) has a second coupling part (24) coupled to the first coupling part (22) and is coupled to the first piston material (23) to form a hollow part (25). A second piston material molding stage for molding a two-piston material (26);
The first and second piston materials (23) and (26) are temporarily coupled, and the temporarily coupled first and second piston materials (23) and (26) are elastically elastically formed by an elastic spring (52). After elastically supporting on the provided support roller (33), the central axis positions of the first and second piston materials (23), (26) are changed to the first and second support means (31a). , (31b) a center axis alignment step for matching each center axis position;
A support step in which the first and second piston materials (23), (26) are rotatably supported by the first and second support means (31a), (31b) after the alignment of the central axis;
In a state where the welding means (40) is rotated and advanced toward the welding site side of the first and second coupling portions (22) and (24), and enters and closely contacts the welding site, the first support means (31a). And / or a welding stage in which friction stir welding is performed by frictional heat generated by rotating the second support means (31b) at a predetermined rotational speed;
A welding means position moving step of moving the welding means (40) that has entered the welding site from the welding site to a predetermined position after the welding of the welding site is completed;
A welding means separating step of detaching the welding means (40) from the welding site;
A manufacturing method of a piston for a variable displacement swash plate compressor.   The welding step is performed by rotating the first and second piston materials (23), (26) by the first support means (31a) and / or the second support means (31b). A method for manufacturing a piston for a variable displacement swash plate compressor according to claim 1 or 2.   The method for manufacturing a piston for a variable capacity swash plate compressor according to claim 1 or 2, wherein the welding means position moving step moves the table (36) by a predetermined distance in the piston axial direction.   The said welding means (40) is moved to the bridge | bridging (21) site | part of the said 1st piston raw material (23) from the said welding site | part by the movement of the said table (36). Manufacturing method of piston for variable capacity type swash plate compressor.   The support roller (33) is connected to the lower side of the support member (34) that supports both ends of the support roller (33) and is vertically moved by an elevating member (53) elastically supported by an elastic spring (52). The method for manufacturing a piston for a variable capacity swash plate compressor according to claim 2, wherein the piston is moved up and down.   The center axis alignment is performed by a first elastically supported on the support roller (33) by a center axis position adjusting guide member (60) provided on the upper side of the second support means (31b). The variable capacity swash plate compression according to claim 2, wherein the compression is performed from a state in which an upper surface of the second piston material (26) is pressurized among the second piston materials (23), (26). Manufacturing method of piston for machine.   After the supporting step of the first and second piston materials, the lower end of the elevating member (53) elastically provided by the elastic spring (52) is fixed to the lower side of the supporting roller (33), The fixing means (70) provided below the lower end portion is advanced to the lower end portion side of the elevating member (53) by the driving means (77), and the upper end portion of the fixing means (70) is moved to the elevating member (53). The method for manufacturing a piston for a variable capacity swash plate compressor according to claim 2, further comprising a support roller fixing step of fixing the support roller (33) by contacting with a lower end of the compressor.

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