KR100300511B1 - Piston and Method of Manufacture - Google Patents

Abstract

The present invention relates to a method for producing an improved piston (22) reciprocating by a swash plate (20) in a compressor. Each piston 22 includes a head 40 and a skirt 42. The head 40 has a cylinder 41 having an open end, and the skirt 42 has a lid 43 for closing the open end of the cylinder 41. The lid 43 is frictionally pressed to the cylinder 41. This method reliably couples the lid 43 to the cylinder 41 and saves manufacturing cost and time.

Description

Piston and Method of Manufacture

The present invention relates to a piston for a compressor used in a vehicle air conditioner, and a method for manufacturing the piston.

Typical compressors include cylinder blocks, which form part of the compressor housing. A cylinder bore is formed in the cylinder block. Each cylinder bore mutually receives a piston. Each piston has a metal head housed within an associated cylinder bore and a metal skirt connected to a drive, such as a swash plate, for example in a swash plate compressor. The head includes a hollow cylinder having a closed end and a lid for closing the opening of the cylinder. The lid is integrally formed with the skirt.

Such pistons are known as hollow pistons. Compared with the solid piston with a solid head, the hollow piston is light. Use a hollow piston to reduce the weight. The head and skirt of the solid piston are integrally formed, for example by casting. However, the cylinder and lid of the hollow piston are independently formed and welded.

Typically, the cylinder and lid of the hollow piston are welded by electron beam welding. In electron beam welding, a highly accelerated electron beam is irradiated to the portion to be welded in the vacuum welding chamber. However, electron beam welding has the following drawbacks.

(1) The electron beam welding apparatus has a vacuum container, an ejecting apparatus, an electron gun, a high power source, and a controller, which divides the welding chamber and the electron gun chamber. Thus, the electron beam welding apparatus is large and increases the manufacturing cost.

(2) The electron beam is to be irradiated continuously along the bond between the skirt of the piston and the cylinder. This complicates and slows the welding.

(3) Welding the skirt to the cylinder can generate bubbles in the metal forming the cylinder and the lid. This lowers the strength of the bond between the cylinder and the lid, lowers the appearance of the piston, and may hinder the smooth reciprocation of the piston.

It is an object of the present invention to provide an inexpensive piston in which a cylinder and a lid are fastened securely to each other and a method of manufacturing such a piston.

In order to achieve the above and other objects, and in connection with the object of the present invention, a method of manufacturing a piston cooperating with a drive body in a machine is provided. The piston has a skirt and a head. The skirt serves to connect the piston to the drive body, the head having one or more open ends and a lid for closing the open ends. The manufacturing method includes friction welding the lid to the cylinder.

The invention is also embodied in a piston that cooperates with the drive body in a mechanism. The piston includes a skirt and a head that serve to connect the piston to the drive body. The head includes a cylinder having one or more open ends and a lid for closing the open ends.

Other features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings which illustrate the main examples of the invention.

1 is a cross-sectional view showing a variable displacement compressor having a piston according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the piston of FIG. 1. FIG.

3 is a timing diagram showing a process of assembling the cylinder and the skirt of the piston of FIG.

4 is a sectional view showing a piston according to a second embodiment;

4A is an enlarged view of an area surrounded by the dashed circle in FIG. 4;

5A is a cross-sectional view illustrating a method of assembling a cylinder and a skirt of the piston of FIG. 4.

FIG. 5B is an enlarged partial view of an area surrounded by the dashed circle in FIG. 5A;

5C is a cross-sectional view illustrating a method of assembling a cylinder and a skirt of the piston of FIG. 4.

FIG. 5D is a partially enlarged view of an area surrounded by the dashed circle in FIG. 5C. FIG.

6A is a sectional view showing a method of assembling a cylinder and a skirt of a piston according to the third embodiment;

FIG. 6B is an enlarged partial view of the area indicated by the arrow in FIG. 6A;

6C is a cross-sectional view illustrating a method of assembling a cylinder and a skirt of a piston according to the third embodiment;

FIG. 6D is a partially enlarged view of the area indicated by the arrow in FIG. 6C; FIG.

7A is a sectional view showing a method of assembling a cylinder and a skirt of a piston according to the fourth embodiment;

FIG. 7B is a partial sectional view of a roller different from the roller of FIG. 7A. FIG.

FIG. 7C is a partial cross-sectional view showing a roller different from the rollers of FIGS. 7A and 7B.

8 is a sectional view showing a piston according to a fifth embodiment;

9 is a sectional view showing a piston according to a sixth embodiment;

10 is a sectional view showing a piston according to a seventh embodiment;

11 is a sectional view showing a piston according to an eighth embodiment;

12 is a sectional view showing a piston according to a ninth embodiment;

Explanation of symbols on the main parts of the drawings

11: front housing 12: cylinder block

12a: cylinder bore 13: rear housing

14 valve plate 15 crankcase

16: drive shaft 19: rotor

20: swash plate 21: hinge mechanism

22: hollow piston 23: shoe

24: suction chamber 25: discharge chamber

26: suction port 27: suction valve cover

28: discharge port 29: discharge valve cover

30: additional path 31: supply path

32: capacity control valve 32a: solenoid

32b: valve body 40: head

41: Cylinder 41a: Cylinder Inner Space

41b: end face of the cylinder facing the lid

41d: end plate of cylinder

41e: end face of the cylinder facing the end plate

41f: end face of the end plate facing the cylinder

41g, 41i: boss of the end plate

41h: cylindrical part of the end plate

41j: Open end connector part of cylinder 41m: End face of cylindrical part

41n: Open end boss of cylinder

42: Skirt 42a: Slot Of Skirt

42b: socket of the skirt 43: lid

43a: boss of the lid 43b: boss end face of the lid

43c: boss annular groove of the lid

201: die 202: roller

L: axis of drive shaft S: axis of piston

P1: first predetermined pressure P2: second predetermined pressure

R: Solder G: Alloy layer of adhesive part

R1: radius of curvature of the axial center recess of the roller

R2: radius of curvature of the axial end of the roller

θ: taper angle of the circumference of the roller

A piston according to a first embodiment will be described with reference to FIGS. 1 to 3. The piston is used in a variable displacement compressor for a vehicle air conditioner.

As shown in FIG. 1, the front housing 11 and the rear housing 13 are fixed to the cylinder block 12. A valve plate 14 is located between the cylinder block 12 and the rear housing 13. The crank chamber 15 is partitioned by the inner wall of the front housing 11 and the front end face of the cylinder block 12.

The drive shaft 16 is rotatably supported by the front housing 11 and the cylinder block 12. The drive shaft 16 is connected to an external drive source or vehicle engine not shown by a clutch device such as an electromagnetic clutch. When the engine is running, the clutch operatively connects the shaft 16 to the engine to rotate the shaft 16.

The rotor 19 is fixed to the drive shaft 16 inside the crank chamber 15. The crank chamber 15 also houses the swash plate 20. The swash plate 20 is supported by the drive shaft 16, slides along the drive shaft 16, and is inclined with respect to the axis L of the drive shaft 16. The hinge mechanism 21 is located between the rotor 19 and the swash plate 20 to rotate the swash plate 20 integrally with the drive shaft 16. The hinge mechanism 21 guides the movement of the swash plate in the axial direction of the drive shaft 16 and the inclination angle of the swash plate with respect to the drive shaft 16. The inclination angle of the swash plate 20 decreases as the swash plate 20 moves in the direction of the cylinder block 12, and increases as the swash plate 20 moves in the direction of the rotor 19.

The cylinder bore 12a is formed inside the cylinder block 12. Each cylinder bore 12a receives a single head hollow piston 22. Each piston 22 is connected to the swash plate 20 by a pair of shoes 23. The shoe 23 converts the rotational motion of the swash plate 20 into a reciprocating motion of each piston 22 in the associated cylinder bore 12a.

The suction chamber 24 and the discharge chamber 25 are partitioned in the rear housing 13. The valve plate 14 has a suction port 26, a suction valve cover 27, a discharge port 28, and a discharge valve cover 29. Each set of ports 26, 28 and valve covers 27, 29 correspond to one of the cylinder bores 12a. As each piston 22 moves from the top dead center to the bottom dead center, the refrigerant gas is sucked from the suction chamber 24 to the corresponding suction port 26, thus opening the suction cover 27 to open the associated cylinder bore 12a. Enter). As each piston 22 moves from the bottom dead center to the top dead center within the associated cylinder bore, the gas inside the cylinder bore 12a is compressed to a predetermined pressure. Thereafter, the gas is discharged to the discharge chamber 25 through the associated discharge port 28, and at the same time, causes the associated valve cover 29 to be opened and opened.

The bleeding path 30 includes a path 30a formed along the axis of the drive shaft 16 and a path 30b formed on the cylinder block 12 and the valve plate 14. The bleeding path 30 connects the crank chamber 15 with the suction chamber 24. The supply path 31 connects the discharge chamber 25 with the crank chamber 15. The displacement control valve 32 is housed inside the rear housing 13 and regulates the supply path 31.

The displacement control valve 32 includes a solenoid 32a and a valve body 32b. Excitation and de-excitation of the solenoid 32a causes the valve body 32b to open and close the supply path 31. The control valve 32 is connected to a computer (not shown). The computer operates the valve body 32b simultaneously with exciting and demagnetizing the solenoid 32a according to the cooling load. Therefore, the control valve 32 regulates the flow of the refrigerant gas from the discharge chamber 25 to the crank chamber 15, and controls the difference between the pressure in the crank chamber 15 and the pressure in the cylinder bore 12a. The inclination angle of the swash plate 20 changes according to the change in the pressure difference. In turn, this changes the stroke of the piston and the capacity of the compressor.

When the solenoid 32a is demagnetized, the valve body 32b opens the supply path 31 to communicate the discharge chamber 25 with the crank chamber 15. Therefore, the refrigerant gas in the discharge chamber 25 flows into the crank chamber 15 through the supply path, thereby raising the pressure in the crank chamber 15. As a result, the inclination angle of the swash plate 20 decreases, and thus the stroke of the piston 22 also decreases. This reduces the capacity of the compressor.

When the solenoid 32a is excited, the valve body 32b closes the supply path 31. This stops the flow of the refrigerant gas from the discharge chamber 25 to the crank chamber 15. The refrigerant gas inside the crank chamber 15 flows to the suction chamber 24 through the bleeding path 30, and lowers the pressure of the crank chamber 15. As a result, the inclination angle of the swash plate 20 is increased and thus the stroke of the piston 22 is increased. This increases the capacity of the compressor.

In this way, the inclination angle of the swash plate 20 is changed in accordance with the pressure change of the crank chamber 15. The stroke of the piston 22 changes according to the inclination angle of the swash plate 20. Hollow pistons are relatively light and therefore have small inertial forces in reciprocating motion. Thus, when a hollow piston is used, the swash plate 20 can be moved to a desired inclination angle position without being greatly affected by the inertia force of the piston 22.

The structure of each piston 22 is demonstrated with reference to FIGS.

As shown in FIGS. 1 and 2, each piston 22 includes a head 40 accommodated in the associated cylinder bore 12a and a skirt 42 connected to the swash plate 20 by the shoe 23. Have The head 40 and skirt 42 are coupled to each other to form a piston 22. The head 40 includes a cylinder 41 and a disc lid 43. The cylinder 41 includes an end plate 41d for closing the end facing the valve plate 14. A slot 42a facing the swash plate 20 is provided in the skirt 42. Slot 42a has a pair of opposing walls. The socket 42b is partitioned inside each wall to receive the shoe 23. The pair of shoes 23 are supported by the socket 42b. Shoe 23 is sandwiched to the outer peripheral portion of the swash plate 20 as shown in FIG.

The lid 43 is integrally formed with the skirt 42. The boss 43a extends from the lid 43. The outer diameter of the boss 43a coincides with the outer diameter of the cylinder 41. The internal diameter of the boss 43a coincides with the internal diameter of the cylinder 41. The cylinder 41 and the skirt 42 are produced by forging or casting a metal such as aluminum or an aluminum alloy.

The cylinder 41 and the lid 43 are fixed to each other by friction welding. First, as shown in FIG. 2, the cylinder 41 and the skirt 42 are arranged so that the end surface 41b of the cylinder 41 faces the end surface 43b of the boss 43a. One of the cylinder 41 or the skirt 42 rotates relative to each other about the axis S of the piston 22. Thereafter, the cylinder 41 and the skirt 42 come into contact with each other. The relative speed of the cylinder 41 and the skirt 42 and the contact pressure of the cylinder 41 and the skirt 42 change as shown in the graph of FIG. 3.

When the pressure between the end faces 41b and 43b reaches the first predetermined pressure P1, the pressure is maintained for a predetermined time. Since the cylinder 41 and the skirt 42 are pressed against each other, the relative rotational movement heats the end faces 41b and 43b. Thereafter, the relative rotational motion is stopped. Thereafter, the contact pressure applied to the cylinder 41 and the skirt 42 increases up to the second pressure P2, and the second pressure is greater than the first pressure P1. As a result, a kind of seizing occurs between the end faces 41b and 43b, so that the cylinder 41 is welded to the skirt 42.

The cylinder 41 is welded to the skirt 42 under atmospheric pressure. Therefore, when the bonding portion of the cylinder 41 and the skirt 42 is heated, the metal forming the cylinder 41 and the skirt 42 is not lowered by bubbles.

1 to 3 have the following advantages.

(1) The cylinder 41 and the skirt 42 are fixed to each other by friction welding. Compared with electron beam welding, friction welding does not require a large welding device, thereby reducing the production cost of the piston 22. The cylinder 41 and the skirt 42 move relative to each other, and the entire end faces 41b and 43b are welded together at the same time. This shortens the welding time as compared to electron beam welding in which the electron beam is guided along the annular bond between the cylinder 41 and the skirt 42.

(2) While the cylinder 41 and the skirt 42 are pressed against each other by the first pressure P1, they rotate relative to each other. Thereafter, the relative rotational motion is stopped, the cylinder 41 and the skirt 42 are pressed against each other by the second pressure P2, and the second pressure P2 is greater than the first pressure P1. . This ensures a fixation between the end faces 41b and 43b. Thereafter, the cylinder 41 and the skirt 42 are surely fixed to each other.

4 to 5D show a method of assembling the piston according to the second embodiment. In the following, differences from the embodiments in FIGS. 1 to 3 are mainly discussed. The outer diameter of the boss 43a coincides with the inner diameter of the cylinder 41. The annular groove 43c is formed in the outer surface of the boss 43a, and in the embodiment in Figs. 4 to 5D, the number thereof is two.

The cylinder 41 and the skirt 42 are fixed to each other by plastic flow and adhesive. The adhesive is part of the lid 43 facing the circumference of the boss 43a and the adjacent end face 41b of the cylinder 41. Is applied to. The adhesive is, for example, a resinous adhesive such as epoxy, polyamide or vinyl acetate.

Thereafter, the skirt 42 is attached to the cylinder 41 so that the lid 43 seals the cylinder 41 internal space 41a. At this time, the outer circumferential surface of the boss 43a is in contact with the inner wall of the cylinder 41, and the lid 43 is in contact with the end face 41b of the cylinder 41.

Thereafter, as shown in FIGS. 5A and 5C, the cylinder 41 and the lid 43 pass through a die 201, the inner diameter of the die being of the cylinder 41 and the lid 43. Slightly smaller than the outer diameter The die 201 strongly presses the cylinder 41 against the boss 43a, whereby a plastic flow of metal forming the cylinder 41 into the groove 43c occurs. Moreover, when the adhesive hardens, the adhesive portion between the cylinder 41 and the skirt 42 is reinforced. The cylinder 41 is fixed to the skirt 42 under atmospheric pressure. Therefore, the metal forming the cylinder 41 and the skirt 42 is not lowered by bubbles. In FIG. 5A, the difference between the inner diameter of the die 201 and the outer diameter of the cylinder and the lid is exaggerated.

As in the embodiment of FIGS. 1-3, the embodiment of FIGS. 4-5D reduces manufacturing costs and shortens manufacturing time. 4 to 5D also have the following advantages.

(1) The cylinder 41 and the skirt 42 are fixed to each other by plastic flow and adhesive. Thus, the cylinder 41 and the skirt 42 are surely bonded to each other.

(2) The annular groove 43c is formed in the boss 43a of the lid 43. The groove 43c complicates the shape of the bonding portion between the cylinder 41 and the skirt 42 and reliably bonds the cylinder 41 and the skirt 42 to each other.

The cylinder 41 and the skirt 42 may be assembled without using an adhesive. That is, the cylinder 41 and the skirt 42 may be joined by only plastic flow.

6a to 6d show a method of assembling the piston according to the third embodiment. Hereinafter, differences from the embodiment of FIGS. 4 to 5D will be mainly discussed. The boss 43a in the embodiment of FIGS. 6A-6D does not have an annular groove 43c. As shown in Fig. 6B, the solder R fills the space between the cylinder 41 and the boss 43a. The solder R is an alloy having a lower melting point than the metal forming the cylinder 41 and the skirt 42. Solder R may be applied to either cylinder 41 or boss 43 prior to assembly. Alternatively, the solder R may be formed like a ring to fit the cylinder 41 or the boss 43. Moreover, the cylinder 41 or the lid 43 may be coated with powder solder (R).

As in the embodiment of FIGS. 4-5D, die 201 is used in the embodiment of FIGS. 6A-6D. The die 201 strongly presses the cylinder 41 against the boss 43a, thus causing a plastic flow between the cylinder 41 and the boss 43a. This creates a number of lattice defects in the metal forming the cylinder 41 and the skirt 42. That is, a hole is formed in the metal. As a result, fine particles of the metal forming the cylinder 41 enter the lattice defect of the skirt 42, and fine particles of the metal forming the skirt 42 enter the lattice defect of the cylinder 41. .

Penetrating the piston 22 through the die 201 puts pressure on the bond between the cylinder 41 and the skirt 42, thus generating heat. The pressure and heat dissipate the solder R, causing the solder R to enter the lattice defects. Moreover, the piston 22 is heated by an external heat source as it passes through the die 201. The heat of the heat source raises the temperature of the solder R above the melting point, and melts the solder R, integrally with the heat caused by the pressure of the bonding portion. The molten solder R diffuses to the bonding portion. The external heat source may be omitted, in which case solid phase diffusion of the solder R occurs.

As schematically shown in FIG. 6D, an alloy layer G is formed at the adhesive portion between the cylinder 41 and the skirt 42. The alloy layer G includes a metal forming the cylinder 41 and the skirt 42 and solder (R). The cylinder 41 and the skirt 42 are fixed to each other by the metal layer G so that there is no boundary between the cylinder 41 and the skirt 42.

The inner diameter of the die 201 or the pressure exerted on the cylinder 41 and the skirt 42 when the piston 22 penetrates the die 201 is such that the strain of the adhesive portion between the cylinder 41 and the skirt 42 is increased. It is determined to be in the range of 3 to 15 percent. For example, when the working pressure is very small, that is, when the strain of the adhesive portion is less than 3 percent, the number of lattice defects is not sufficient. That is, there are not enough holes, and the metal fine particles inside the cylinder 41 and the skirt 42 are not sufficiently mixed. Insufficient pressure also prevents the solder from spreading satisfactorily, weakening the strength of the bond between the cylinder 41 and the skirt 42. Since insufficient pressure slows the diffusion of the solder R, the cylinder 41 must penetrate the die 201 relatively slowly. On the other hand, if the working pressure is relatively large, i.e., the strain rate of the adhesive portion exceeds 15 percent, the piston 22 is severely deformed and the piston 22 requires processing.

After assembling the piston 22 to the die 201, the bond between the cylinder 41 and the skirt 42 is reheated. The temperature preferably exceeds the melting point of the alloy layer (G). The heat promotes diffusion of the alloy layer G, thereby strengthening the adhesive portion between the cylinder 41 and the skirt 42. A laser heater or electron beam heater may be used to heat the bond between the cylinder 41 and the lid 43. Alternatively, the entire piston 22 may be located inside the furnace.

The cylinder 41 and the skirt 42 are manufactured by forging or casting. Thereafter, the cylinder 41 and the skirt 42 are cured and tempered. The cylinder 41 then passes through the die 201. Reheating the piston inside the furnace allows the tempering process to be omitted.

The cylinder 41 and the skirt 42 are preferably produced from the same or different aluminum alloys selected from alloys A2017, A2014, A4032, A6063, A6061, A7075, ADC12 and A390, which are specified in Japanese Industrial Standard (JIS). Suitable materials for the solder (R) are as follows.

(1) An alloy comprising zinc as the first main component, tin as the second main component, aluminum as the third main component, and copper, chromium and beryllium as an adduct.

(2) An alloy comprising tin as the first main component, zinc as the second main component and aluminum, copper and beryllium as an adduct.

(3) An alloy comprising tin as the first main component, zinc as the second main component, and aluminum, copper, chromium and beryllium as adducts.

(4) An alloy comprising tin as the first main component, zinc as the second main component, and copper and silver as an adduct.

(5) An alloy comprising zinc as the first main component, aluminum as the second main component, tin as the third main component, and cadmium, copper, titanium and beryllium as an additive.

(6) An alloy comprising zinc as the first main component, tin as the second main component, and copper and cadmium as adducts.

(7) An alloy comprising zinc as the first main component, aluminum as the second main component, and silicon, copper and titanium as an additive.

(8) An alloy comprising zinc as the first main component, aluminum as the second main component, and titanium, beryllium and copper as adducts.

(9) An alloy comprising zinc as the first main component, aluminum as the second main component, and titanium, cadmium and copper as adducts.

(10) An alloy comprising zinc as the first main component, aluminum as the second main component, and copper, chromium, magnesium and tin as adducts.

In the solder R, the weight percentage of the first main component is at least the weight percentage of the second main component, and when the third main component is present, the weight percentage of the second main component is at least the weight percent of the third main component. The weight percentage of the adduct is very small relative to the main component.

In the embodiment of FIGS. 6A-6D, the bonding portion of the cylinder 41 and the skirt 42 is pressed by the die 201. This generates a plastic flow at the bonding portion to promote the diffusion of the solder (R). 6A-6D reinforce the bond between the cylinder 41 and the skirt 42 as compared to simple soldering where the bond is not pressurized.

In the fourth embodiment shown in FIGS. 7A-7C, the die 201 of the embodiment shown in FIGS. 4-6D is replaced with a roller 202. The piston 22 rotates about its axis. At the same time, the roller 202 is strongly pressed against the bonding portion between the cylinder 41 and the boss 43a. This produces a plastic flow at the bond. The piston 22 shown in FIG. 7A has a groove formed on the circumference of the boss 43a like the piston 22 of FIG. 4. However, the groove may be omitted. As in the embodiment of FIGS. 4-5D, an adhesive may be used in the embodiment of FIG. 7A. Also, as in the embodiment of FIGS. 6A-6D, solder may be used in the embodiment of FIG. 7A.

The diameter of each roller 202 shown in FIG. 7A is constant along its axis. That is, the surface of the roller 202 is cylindrical. Thus, the entire circumferential surface of the roller 202 is pressed against the piston 22. When using such a roller 202 for assembly, the piston 22 is heated to a relatively high temperature and the roller 202 is pressed against the piston 22 at a relatively low pressure. Moreover, assembly takes a relatively long time. In particular, in each roller 202 of FIG. 7A, the compressive force per unit area of the roller 202 is relatively small, thus generating a relatively small plastic flow in the bond. On the other hand, the large pressing area and the long assembly time of the roller 202 of FIG. 7A raise the temperature at the bonding portion. Thus, if solder is used, the solder diffuses smoothly. The axial length of the roller 202 is determined such that the plastic flow at the bond is sufficient to ensure the strength of the bond and that plastic flow does not occur at other portions of the piston.

7B shows another type of roller 202. The circumferential surface of the roller 202 of FIG. 7B is a circular curve in which the axial center of the roller 202 is concave. The radius of curvature R2 at the axial end of the roller 202 may be a very small value. When using the roller 202 of FIG. 7B, the piston 22 is heated to a relatively low temperature, and the roller 202 is pressed to a relatively high pressure against the piston 22. Moreover, this process takes a relatively short time. Compared with the case where the roller 202 of FIG. 7A is used, the plastic flow in the bonding portion is greatly promoted, and the bonding portion is not heated to high temperature. The shape of the roller 202, in particular the radius of curvature R1 of the recess in the axial center, is optimized to effectively generate plastic flow at the bonds to minimize the energy required to connect the cylinder 41 to the skirt 42. do.

7C shows another type of roller 202. The circumferential surface of the roller 202 of FIG. 7C is tapered at a predetermined angle θ. When using the roller 202 of FIG. 7C, the piston 22 is heated to a relatively low temperature and the roller 202 is pressed to a relatively high pressure against the piston 22. Moreover, this process takes a relatively short time. The plastic flow at the bond is very promoted and the bond is not heated to high temperatures. The angle [theta] is optimized to effectively generate plastic flow at the bond and to minimize the energy required to connect the cylinder 41 to the skirt 42.

In the embodiment shown in Figs. 8 to 12, the head 41 and the skirt 42 of each piston 22 are formed integrally, and the end plate 41d is formed independently of the cylinder 41. The cylinder 41 and the end plate 41d are interconnected by plastic flow or friction welding as shown in Figs. 1 to 7C.

8 shows a method of manufacturing the piston 22 according to the fifth embodiment. The end plate 41d is disk-shaped. The end face 41e of the cylinder 41 and the end face 41f of the end plate 41d come into contact with each other. Thereafter, the cylinder 41 and the end plate 41d are interconnected by friction welding or plastic flow.

9 shows a piston 22 according to the sixth embodiment. The end plate 41d includes a boss 41g. The outer diameter of the boss 41g coincides with the inner diameter of the cylinder 41. The boss 41g is fitted to the cylinder 41 so that the end faces 41e and 41f contact each other. Thereafter, the cylinder 41 and the end plate 41d are interconnected by friction welding or plastic flow.

10 shows a piston 22 according to the seventh embodiment. The cylindrical portion 41h is integrally formed with the end plate 41. The outer diameter of the cylindrical portion 41h coincides with the outer diameter of the cylinder 41. The end face 41m of the cylindrical portion 41h and the end face 41e of the cylinder 41 come into contact with each other. Thereafter, the cylinder 41 and the end plate 41d are interconnected by friction welding or plastic flow.

11 shows a piston 22 according to the eighth embodiment. The piston 22 of FIG. 11 is a variant of the piston of FIG. 10. That is, the cylindrical portion 41h of the end plate 41d includes the boss 41i. The outer diameter of the boss 41i is smaller than the remainder of the cylindrical portion 41h. The cylinder 41 includes a connector portion 41j formed at the open end. The inner diameter of the connector portion 41j coincides with the outer diameter of the boss 41i. The boss 41i is fitted to the connector portion 41j such that the end face 41e of the cylinder 41 contacts the end face 41m of the cylindrical portion 41h. Thereafter, the cylinder 41 and the end plate 41d are interconnected by friction welding or plastic flow.

12 shows a piston 22 according to the ninth embodiment. The piston 22 of FIG. 12 is a variant of the piston of FIG. 10. That is, the inner diameter of the cylindrical portion 41h is larger than the inner diameter of the cylinder 41. The cylinder 41 includes a boss 41n at the open end. The outer diameter of the boss 41n coincides with the inner diameter of the cylindrical portion 41h. The boss 41n is fitted to the cylindrical portion 41h such that the end surface 41e of the cylinder 41 contacts the end surface 41m of the cylindrical portion 41h. Thereafter, the cylinder 41 and the end plate 41d are interconnected by friction welding or plastic flow.

It is apparent to those skilled in the art that the present invention may be configured in other specific forms without departing from the scope of the invention. In particular, the present invention may be configured in the following form.

1-7C, one or both of cylinder 41 or skirt 42 may be produced from a metal other than aluminum or an aluminum alloy, such as iron or iron alloy or copper or copper alloy. have. 8 to 12, one or both of the cylinder 41 or the end plate may be produced from a metal other than aluminum or an aluminum alloy, such as iron or iron alloy or copper or copper alloy. have.

The invention may be embodied in a piston other than the piston 22 of FIGS. 1 to 12, which piston is used in a swash plate compressor. For example, the invention may be embodied in a piston of a wave cam plate type compressor, a piston of a double-head piston type variable displacement compressor, a piston of an air compressor, and a piston of a reciprocating internal combustion engine.

Accordingly, the present embodiments are illustrative and not restrictive, and the invention is not limited to the above, and may be modified within the scope and equivalents of the claims.

Claims (17)

It has a skirt 42 and a head 40, the skirt 42 serves to connect the piston 22 to the drive body 20, the head 20 is one or more open end and the open end In the manufacturing method of the piston 22 which cooperates with the drive body 20 in a machinery which includes the cylinder 41 which has the lid 43; A piston manufacturing method, characterized in that the lid is friction-welded to the cylinder. The method according to claim 1, wherein the relative rotational movement of the lid (43; 41d) and the cylinder (41) is generated for a predetermined time while the lid (43; 41d) and the cylinder (41) are pressed against each other with a predetermined force. A piston manufacturing method characterized by the above-mentioned. 3. The lid (43; 41d) and the cylinder (4) according to claim 2, wherein the lid (43; 41d) and the cylinder (41) are pressed against each other in the axial direction of the piston (22) and around the axis of the piston (22). 41) A method for producing a piston, characterized in that to generate a relative rotational motion of. 3. The method according to claim 2, wherein after generating the relative rotational motion of the lid (43; 41d) and the cylinder (41), pressing the lid (43; 41d) and the cylinder (41) against each other with a force greater than a predetermined force. A piston manufacturing method characterized by the above-mentioned. The piston manufacturing method according to any one of claims 1 to 4, wherein the manufacturing method is performed under atmospheric pressure. It has a skirt 42 and a head 40, the skirt 42 serves to connect the piston 22 to the drive body 20, the head 20 is one or more open end and the open end In the manufacturing method of the piston 22 which cooperates with the drive body 20 in a machinery which includes the cylinder 41 which has the lid 43; Generating a plastic flow between the lid and the cylinder to couple the lid to the cylinder. 7. The method according to claim 6, characterized in that the lids (43; 41d) and the cylinder (41) are pressed against each other to generate plastic flow between the lids (43; 41d) and the cylinder (41). Piston manufacturing method. 8. A cylindrical boss (43a) is formed in the lid (43; 41d), Fitting the cylindrical boss 43a into the opening of the cylinder 41, And the cylinder (41) is pressed against the cylindrical boss (43a) to generate a plastic flow between the cylinder (41) and the cylindrical boss (43a). 9. An annular groove (43c) is formed on an outer surface of the cylindrical boss (43a), and the cylinder boss (43a) is circumferentially pressed when the cylinder (41) is radially pressed against the cylindrical boss (43a). A portion of the cylinder (41) located at is introduced into the annular groove (43c) by plastic flow. 9. A cylinder according to claim 8, wherein the cylinder (41) is penetrated through the die (201) to radially press the cylinder (41) against the cylindrical boss (43a). The piston manufacturing method characterized by being slightly smaller than the outer diameter of the cylinder (41). 9. A method according to claim 8, wherein the cylinder (41) is rotated about an axis of the cylinder (41) while the roller (202) is pressed against the cylinder (41). The piston manufacturing method according to any one of claims 6 to 11, wherein an adhesive is applied between the lid (43; 41d) and the cylinder (41). The piston manufacturing method according to any one of claims 7 to 11, wherein solder is applied between the lid (43; 41d) and the cylinder (41). 7. The piston manufacturing method according to claim 6, wherein the solder is heated to a temperature higher than the melting point of the solder while the lid (43; 41d) and the cylinder (41) are pressed against each other. 12. The piston manufacturing method according to any one of claims 6 to 11, wherein the upper limb manufacturing method is performed under atmospheric pressure. In the piston 22 which cooperates with the drive body 20 in a machine, A skirt 42 acting to connect the piston 22 to the drive body 20; A cylinder 41 having at least one open end and a head 40 having a lid 43; 41d for closing the open end, And the lid (43; 41d) is frictionally pressed against the cylinder (41). In the piston 22 which cooperates with the drive body 20 in a machine, A skirt 42 acting to connect the piston 22 to the drive body 20, A cylinder 41 having at least one open end and a head 40 having a lid 43; 41d for closing the open end, The piston (43; 41d) is coupled to the cylinder (41) by the plastic flow between the lid (43; 41d) and the cylinder (41).