KR100558703B1 - Piston for wobble plate type compressor - Google Patents

Abstract

The present invention relates to a piston having a structure for minimizing stress applied to a piston suitable for use in a swash plate compressor, comprising: a cylinder head reciprocally disposed in each cylinder bore; A half cylinder shaped outer segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A semicylindrical inner segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A recess having a pair of shoe pockets formed in the recess and connected to the head via outer and inner segments; And stress distribution means for preventing the piston from being changed or broken by dispersing the stress applied to the piston during suction and compression stroke of the piston. By including, the bending moment acting during the compression stroke to the piston for use in the swash plate type compressor is minimized to prevent uneven wear of the piston and the cylinder bore, as well as to prevent deformation or breakage of the piston.

In addition, the deflection of the swash plate can be prevented to prevent rolling or uneven wear of the swash plate, and the stress due to the external force acting on the piston can be effectively dispersed to prevent deformation and breakage of the piston, thereby improving durability of the compressor.

Description

Piston for minimizing stress {Piston for wobble plate type compressor}

1 is a longitudinal sectional view of a variable displacement swash plate compressor of the prior art;

2 is an enlarged view of a portion of FIG. 1 to show the various forces acting on the piston and thus the deformation of the piston;

3 is a longitudinal sectional view of a variable displacement swash plate compressor having a mechanism for minimizing a bending moment according to the present invention;

FIG. 4 is an explanatory view illustrating main parts of a mechanism for minimizing bending moment in the compressor of FIG. 3; FIG.

5 is a partial cross-sectional view of the swash plate illustrating the formation of a depression in the swash plate rear surface to prevent contact between the piston edge and the swash plate rear surface;

6A is a cross-sectional view of a piston according to an embodiment suitable for use with the compressor of FIG. 3, and FIG. 6B is a cross-sectional view taken along line B-B of FIG. 6A;

7A is a cross-sectional view of a piston according to another embodiment suitable for use with the compressor of FIG. 3, and FIG. 7B is a cross-sectional view taken along line C-C of FIG. 7A;

8A is a cross-sectional view of a piston according to another embodiment suitable for use with the compressor of FIG. 3, and FIG. 8B is a cross-sectional view taken along line D-D of FIG. 8A;

FIG. 9A is a piston stage shaving in accordance with another embodiment suitable for use with the compressor of FIG. 3, and FIG. 9B is a cross-sectional view taken along line E-E of FIG. 9A.

* Description of the symbols for the main parts of the drawings *

110; piston 112; head

114; segment 116; outer segment

118; inner segment 122; support

126; pocket 154,156; rib

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a piston-type compressor, and more particularly to a variable displacement swash plate compressor suitable for use in a vehicle air conditioner system, and a piston having a structure for minimizing a bending moment and a bending moment according to such a piston structure. Mechanisms for minimizing are provided.

As an example a piston type compressor for use in a vehicle air conditioning system comprises a cylinder block having a plurality of cylinder bores. In each cylinder bore, the piston is slidably arranged such that it is reciprocated in the cylinder bore by means of a swash plate, for example.

Variable-capacity swash plate compressors with a mechanism for changing the swash plate tilt angle generally use a single-headed piston, which converts the rotational movement of the body and the swash plate into the reciprocating motion of the piston. And a support for accommodating shoes.

However, a bending moment acts on the piston due to the force acting on the piston during operation of the compressor, and the head portion and the cylinder bore of the piston are unevenly worn by the bending moment.

Referring to FIG. 1 for understanding a problem occurring in a conventional swash plate type compressor with a variable displacement mechanism, a swash plate compressor 1 having a variable displacement mechanism may be provided. It has a cylinder block (2) having a cylinder bore (4), and both ends of the cylinder block (2) are closed by the front housing (6) and the rear housing (8).

The cylinder block 2 and the front housing 6 define a crank chamber 10 in a gas tight state therebetween. A valve plate 12 is interposed between the rear end of the cylinder block 2 and the rear housing 8, and the rear housing 8 has an inlet 14 for inlet and outlet of refrigerant gas, an outlet 16, and a suction chamber. 18 and the discharge chamber 20 are formed.

The suction chamber 18 and the discharge chamber 20 communicate with each cylinder bore 4 and the refrigerant through the suction and discharge valve mechanisms, respectively. The drive shaft 22 is rotatably installed across the front housing 6 and the cylinder block 4, and is also rotatably supported by bearings 24 mounted to the front housing 6 and the cylinder block 2. do. The cylinder block 2 and the front and rear housings 6 and 8 are coupled by a through screw 25.

In the crank chamber 10, a rotor 26 is rotatably mounted together with the drive shaft 22, and the rotor 26 is attached to a thrust bearing 28 installed at an inner end of the front housing 6. Is supported by. A spherical sleeve 30 having a spherical outer surface serving as a support surface is slidably supported by the drive shaft 22. The spring 32 provided around the drive shaft 22 is interposed between the rotor 26 and the spherical sleeve 30 to push the spherical sleeve 30 toward the rear housing 8.

The swash plate 34 is rotatably supported on the outer support surface of the spherical sleeve 12, and the swash plate 34 and the rotating body 26 are connected by a hinge mechanism so that the swash plate 34 is connected to the rotating body 26. Will rotate together. That is, the support arm 36 protrudes outward along an axis from one side of the rotor 26, and the arm 38 protrudes from one surface of the swash plate 34 toward the support arm 36 of the rotor 26. do.

The support arm 36 and the arm 38 are connected to each other by the pin 40, which pin 40 is formed through the support arm 36 of the rotating body 26 and the swash plate 34 It extends through the substantially rectangular hole 43 formed long through the arm 38 of the). As such, the rotating body 26 and the swash plate 34 are hinged to each other so that the inclination angle of the swash plate 34 is changed by the sliding motion of the pin 40 in the rectangular hole 43, and thus the capacity of the compressor Will change.

Pistons 44 are slidably arranged in the respective cylinder bores 4, and each piston 44 has a body 46 and a support 48 which are slidably arranged in the cylinder bores 4. A recess 50 is formed in the support 48 of the piston 44, and the outer circumferential portion of the swash plate 34 is positioned in the recess 50. The hemispherical shoes 52 are disposed in a shoe pocket 54 formed in the support 48 of the piston 44 to be in sliding engagement with both sides of the outer circumferential portion of the swash plate 34.

Therefore, as the drive shaft 22 rotates, the swash plate 34 also rotates, and the rotational movement of the swash plate 34 is converted to the reciprocating motion of the piston 44 through the shoes 52. A cutout portion 56 is formed at the lower left end of the piston 44, which is a surface of the swash plate 34 and the piston when the piston 44 is located at the bottom dead center. In order to prevent the edges of the body 46 of the 44 from being in contact with each other. The rear housing 8 is provided with a control valve 60 to adjust the pressure level of the crank chamber 10.

In the compressor having the above-described structure, a variety of forces are applied to the piston 44, the deformation of the connection portion of the body 46 and the support portion 48 of the piston 44 due to the bending moment is Will occur.

Referring to Figure 2, Figure 2 shows the various forces acting on the piston. During the compression stroke, the pressure Pc of the crank chamber 10 acts on one end of the piston 44 and the compression reaction force Pd acts on the other end. The pressure Pc and the compression reaction force Pd of the crank chamber 10 act on the swash plate 34 through the shoes 52 and the force acting on the swash plate 34 has the same magnitude but is the opposite direction as the reaction force. Again acting on the piston 54 through the shoes (52). That is, when the piston 44 is subjected to the compression stroke, the force F acting on the piston 44 through the shoe 52 located on the right side of the swash plate 34 from the swash plate 34 is applied to the right shoe 52. The hemispherical outer surface and the hemispherical inner surface of the shoe pocket 54 act on the piston 44 while maintaining a constant angle with the central axis 0 of the piston 44 at a contact position with each other. It is located on the central axis (0) of. The force F applied to the piston 44 by the swash plate 34 is perpendicular to the force Fx of the horizontal component coinciding with the center axis 0 of the piston 44 and the center axis 0 of the piston 44. It can be divided by the force (Fy) of the phosphorus vertical component. When the mass of the piston 44 is m and the compression stroke is performed, the piston 44 moves at an acceleration of a, and when the cross-sectional area of the piston 44 is A, the force Fx of the horizontal component is

∑Fx = APc ­APd + Fx

At ∑Fx = ma,

Fx = ma + A (Pd-Pc)

= ma + π / 4 D ² (Pd-Pc) (1)

(D is the diameter of the piston 44),

The force (Fy) of the vertical component is

Fy = Fx tanθ

= tanθ [ma + π / 4 D ² (Pd-Pc)] (2)

It is expressed as

The force Fy of the vertical component acts as a bending moment on the piston 44, the bending moment at the inner edge of the connection where the head 46 and the support 48 of the piston 44, denoted by P, are connected to each other. Will work to the maximum. That is, when the piston 44 is located at the bottom dead center, the cutout 56 is formed at the inner edge of the connection portion of the piston 44 to prevent one side of the swash plate 34 and a part of the body of the piston 44 from contacting each other. Is provided between the point of action of the force F applied to the piston due to the cutout 56 and the reaction force point P of the inner edge of the cutout 56 by X as shown in FIG. 2. The distance of is generated, the bending moment acts on the piston by this distance (X). That is, the maximum bending moment (Mmax) on the piston is

Mmax = xFy

= x tanθ [ma + π / 4 D ² (Pd-Pc)] (3)

Becomes

Accordingly, since the piston 44 receives the bending moment counterclockwise by the distance X about the reaction force point P, a bending deformation occurs in the piston 44, and thus the head portion 46 of the piston 44 Uneven wear due to abnormal contact occurs in the cylinder bore 4.

On the other hand, in the variable capacity swash plate type compressor of the above-described structure, the compressor is also driven at a high speed during the high-speed operation of the vehicle, when the compressor is driven at a high speed, the amount of refrigerant circulated in the air conditioning system, although the total amount of refrigerant in the air conditioner system Is increased, the inclination angle of the swash plate 34 of the compressor is minimal and the compressor tends to operate at the minimum capacity. At the same time, however, when the compressor is driven at high speed, the piston 44 tends to operate at maximum capacity as the maximum stroke length by the force of inertia, and consequently, when the compressor is driven at high speed, A condition in which capacity control is impossible occurs.

In order to solve the above problems, when the empty space is formed in a certain portion of the piston to reduce the inertia force by reducing the mass of the piston, an external force applied to the piston such as a bending moment due to the empty space formed in the piston. There is a problem in that the stress received per unit area of the piston is increased so that the piston is easily deformed or broken.

SUMMARY OF THE INVENTION An object of the present invention is to provide a swash plate compressor having a piston for solving the above-mentioned problems occurring in a conventional compressor.

Another object of the present invention is to provide a piston having a structure for minimizing a bending moment suitable for use in a variable displacement swash plate compressor, thereby improving the durability of the piston and thus improving the durability of the compressor.

It is yet another object of the present invention to provide a piston having a structure for minimizing the stress acting on a piston suitable for use in a swash plate compressor, thereby improving the durability of the piston.

Another object of the present invention is to provide a swash plate compressor having a mechanism for minimizing bending moments.

Piston for minimizing the stress in accordance with the present invention is a piston that is reciprocally disposed in each of the plurality of cylinder bores, the cylinder-shaped head; A half cylinder shaped outer segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A semicylindrical inner segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A recess having a pair of shoe pockets formed in the recess and connected to the head via the outer and inner segments; And stress distribution means for preventing the piston from being changed or broken by dispersing stress applied to the piston during suction and compression stroke of the piston. Characterized in that it comprises a.

3 is a longitudinal sectional view of a compressor having a mechanism for minimizing bending moments, for example a variable capacity swash plate compressor, in which a variable capacity swash plate type compressor 70 is a plurality of cylinders. It has a cylinder block 72 with a bore 74, a front housing 76, and a rear housing 78. Both ends of the cylinder block 72 are coupled to be sealed by the front housing 76 and the rear housing 78, respectively, and a valve plate 80 is provided between the cylinder block 72 and the rear housing 78. It is interposed. The cylinder block 72 and the front housing 76 define an air-tight sealed crank chamber 82.

The drive shaft 84 is arranged to extend beyond the front housing 76 to the cylinder block 72 and is rotatably supported by the radial bearings 85, 86, 87. The cylinder block 72 and the front and rear housings 76 and 78 are coupled to each other by screws 89 of the long shaft.

The rotor 90 is fixedly mounted to the drive shaft 84 located in the crank chamber 82 so as to rotate together with the drive shaft 84. The rotor 90 is supported by a thrust bearing 92 provided at an inner end of the front housing 76. The swash plate 94 is rotatably supported by the drive shaft 84, and a spherical sleeve may be interposed between the drive shaft 84 and the swash plate 94, in which case the swash plate 94 is It is rotatably supported on the outer support surface of the spherical sleeve.

In FIG. 3, the swash plate 94 is in the position of the maximum inclination angle, in which the spring 98 is in the maximum compressed state, and the stop surface 96a of the protrusion 96 is in contact with the rotating body 90. Since the inclination angle of the swash plate 94 is limited by the rotating body (90).

The swash plate 94 and the rotating body 90 are connected by a hinge mechanism so that the swash plate 94 rotates together with the rotating body 90. That is, the support arm 100 protrudes outward along an axis from one side of the rotating body 90, and the arm 102 protrudes from one surface of the swash plate 94 toward the supporting arm 100 of the rotating body 90. do. The support arm 100 and the arm 102 are connected to each other by the pin 104, the pin 104 and the pin hole 106 and the swash plate 94 formed through the support arm 100 of the rotating body 90 It extends through the generally rectangular hole 108 formed long through the arm 102 of the ().

Thus, the rotating body 90 and the swash plate 94 are hinged to each other so that the inclination angle of the swash plate 94 is changed by the sliding motion of the pin 104 in the rectangular hole 108, and thus the capacity of the compressor Will change.

As illustrated in FIG. 4, each cylindrical piston 110 has a connecting segment for connecting the cylindrical head 112, the support 122, and the support 112 and the support 112. (114). The connecting segment 114 has a semi-cylindrical inner segment 118 and a semi-cylindrical outer segment 116, each of the inner and outer segments 116, 118 having a head ( Extends from 112 to support 122 along central axis 0 of piston 110.

Thus, a cavity 120 is formed in the connecting segment 114. The lengths of the inner and outer segments 116, 118 extending from the head 112 to the support 122 are the same. The support 122 is provided with a recess 124 having a pair of shoe pockets 126 formed therein such that a pair of hemispherical shoes 128 correspondingly have a pair of shoe pockets formed in the recess 124. It is slidably disposed at 126.

The inner surfaces of the hemispherical shoes 128 are in sliding contact with the swash plate 94 at both sides on the outer circumferential surface of the swash plate 94. As such, the individual pistons 110 are engaged with the swash plate 94 through the shoes 128 and the shoe pockets 126, so that each of the pistons 110 is in the cylinder bore 74 as the swash plate 94 rotates. It will take you back and forth from.

In the compression stroke of the piston 110, the force F applied by the swash plate 94 to the piston 110 through the right shoe 128 is determined by the shoe pocket 126 corresponding to the hemispherical outer surface of the right shoe 128. Constant angle with respect to the central axis (0) of the piston 110 at the contact surface (in case of line contact) or contact point (in case of contact point) (hereafter collectively referred to as "contact position") of the hemispherical inner surface in contact with each other. It acts on the piston 110 while maintaining the contact position (Q) is located on a plane coincident with the central axis of the piston (110). The force F applied to the piston 110 by the swash plate 94 is perpendicular to the force Fx of the horizontal component coinciding with the center axis 0 of the piston 110 and the center axis 0 of the piston 110. It can be divided by the force (Fy) of the vertical component, the force (Fy) of the vertical component is acting on the piston 110 as a bending moment.

With respect to the plane S perpendicular to the central axis 0 of the piston 110 passing through the contact position Q in which the hemispherical outer surface of the right shoe 128 and the corresponding hemispherical inner surface of the shoe pocket 126 correspond to each other. The connecting segment 114 outer segment 116 and inner segment 118 of the piston 110 are each formed to have the same length. That is, as shown in FIG. 4, the cutout portion as shown in FIGS. 1 and 2 is not formed in the left edge portion of the inner segment 118.

Thus, the inner segment 118 results in a length x being compensated for the piston in which the cutout is formed. Therefore, the maximum bending moment acting on the piston 110 from the above equation (3) converges to zero, and consequently, the bending moment acting on the piston 110 is minimized.

If no cutout is formed in the inner segment 118 of the piston 110, the piston 110 located at the bottom of the compressor, ie the inner segment of the piston 110 located at the bottom dead center in the maximum suction stroke, of the piston 110. The edge 119 opposite the swash plate 94 of 118 comes into contact with the rear face of the swash plate 94. Thus, instead of forming a cutout in the inner segment 118 of the piston 110, a depressed portion 130 is formed in the swash plate 94. The depression 130 may be formed only in a portion where the rear surface of the swash plate 94 and the edge 119 of the inner segment 118 of the piston 110 come into contact with each other. It may be formed to extend along the direction.

Referring to FIG. 5, the depression 130 is elongated along the rear surface of the swash plate 94 to cover a point where the edge E of all the pistons 110 are located.

At this time, the depth of the depression 130 is preferably maintained to 1/2 of the thickness of the outer region (part in contact with the shoe) of the swash plate 94, the bottom surface of the depression 130 is the swash plate 94 is a shoe ( And a plane U passing through the central axis of the swash plate 94 parallel to the rear face of the outer region, which is in contact with 128. In addition, it is preferable to form a protuberant portion 132 about the depth of the depression to increase the strength of the swash plate on the opposite side of the depression 130.

Thus, by forming the depressions 130 and the ridges 132 in the inner region of the swash plate 94, it is possible to maintain the balance between the rotation axis center of the swash plate 94 and the center of gravity of the swash plate, thus deflection of the swash plate 94 And rolling can be prevented.

The rear housing 78 has an inlet 134 and an outlet 136, a suction chamber 138, and a discharge chamber 140 for inflow and outflow of the refrigerant gas. The individual cylinder bores 74 communicate with the suction chamber 138 and the discharge chamber 140 through the inlet 142 and the outlet 144 formed in the valve plate 80, respectively.

Each inlet 142 is closed by the inlet valve 146 and the inlet valve 146 opens and closes the inlet 142 according to the reciprocating motion of the piston 110. Each discharge port 144 is closed by the discharge valve 148 and the discharge valve 148 opens and closes the discharge port 144 according to the reciprocating motion of the piston 110. Retainer 150 limits the degree of opening of discharge valve 148.

The compressor 70 is provided with a control valve 152 to change the inclination angle of the swash plate 94 by adjusting the fluid pressure level in the crank chamber 82.

Referring to the operation of the compressor having the above-described structure, when the drive shaft 84 rotates, the swash plate 94 also rotates through the hinge mechanism, so that the rotational movement of the swash plate 94 through the shoes 128 is a piston ( Is converted to reciprocation in the individual cylinder bores 74 of 110. Accordingly, the refrigerant gas flows into the respective cylinder bores 74 from the suction chamber 138 of the rear housing 78 and is compressed by the reciprocating motion of the piston 110. The compressed refrigerant gas is discharged from the respective cylinder bores 74 to the discharge chamber 140.

At this time, the amount of the refrigerant gas discharged from the individual cylinder bores 74 to the discharge chamber 140 is controlled by the control valve 152 for adjusting the pressure level of the crank chamber 82. That is, when the load of the evaporator increases, the pressure Psc in the suction chamber 138 becomes high, and accordingly, the control valve 152 blocks the refrigerant gas that is moved from the discharge chamber 140 to the crank chamber 82, so that the crank The pressure level Pcc of the seal 82 is lowered.

When the pressure level of the crank chamber 82 is lowered, the back pressure acting on each piston 110 is reduced, and thus the inclination angle of the swash plate 94 is increased. In other words, the pin 104 constituting the hinge means is slid along the rectangular hole 108 toward the upper end of the rectangular hole 108. Thus, the swash plate 94 is moved forward of the compressor against the spring 98 force. As such, the inclination angle of the swash plate 94 is increased, and as a result, the stroke length of each piston 110 is extended to increase the compression capacity of the compressor.

On the other hand, when the load of the evaporator decreases, the pressure Psc in the suction chamber 138 is lowered, and the control valve 152 sends the compressed refrigerant gas of the discharge chamber 140 to the crank chamber 82. The pressure level Pdc of the discharge chamber 140 is in a state. As the pressure level of the crank chamber 82 increases, the back pressure acting on each piston 110 increases, so that the inclination angle of the swash plate 94 decreases. That is, the pin 104 constituting the hinge means is slid along the rectangular hole 108 toward the lower end of the rectangular hole 108. Thus, the swash plate 94 is moved to the rear of the compressor, thereby reducing the inclination angle of the swash plate 94. As a result, the stroke length of the piston 110 is shortened and the compression capacity of the compressor is reduced.

During the compression stroke of the compressor described above, each piston 110 acts on the pressure and compression reaction of the crank chamber 82, and these forces act on the swash plate 94 through the shoes 128, Reaction force in the same but opposite direction is applied to the piston 110 from the swash plate 94 via the shoes 128.

At this time, the maximum bending moment acts on the reaction force point P of the portion of the inner segment 118 of the piston 110 that faces the swash plate 94, but the inner segment 118 of the piston 110. Since the connection segment 114 of the piston 110 is compensated by the length x because the cutout is not formed in the groove, the maximum bending moment acting on the piston 110 from Equation (3) converges to zero and thus the piston The bending moment acting on 110 is minimal. As a result, uneven wear due to abnormal contact between the piston 110 and the cylinder bore 74 can be prevented, and the piston 110 can be prevented from being deformed or damaged, thereby improving the compression performance of the compressor.

6-9 are cross-sectional views of pistons suitable for use with the compressor of FIG. 3. 6A and 6B, the piston 110 includes a head 112, a support 122, and a connecting segment 114 extending between the head and the support, the connecting segment 114 having an outer segment 116. And an inner segment 118.

The radial thickness of the outer segment 116 is smaller than the radius of the head 112 at all points, and the radial thickness of the inner segment 118 is also formed smaller than the radius of the head 112 at all points.

Thus, a cavity 120 is formed between the outer and inner segments 116, 118 of the connecting segment 114. And, the outer and inner segments 116 and 118 each have a uniform thickness and extend.

Here, the process in which the piston 110 compresses the refrigerant gas while reciprocating in the cylinder bore 74, in front of the piston 110, that is, the compression reaction force and the refrigerant gas in accordance with the compression of the refrigerant gas on the side of the head 112. Suction reaction force acts as a result of the suction, and the pressure of the crank chamber 82 is applied through the swash plate 94 to the rear of the piston 110 to apply a bending moment to the piston, so that the inner segment of the piston 110 Tensile and compressive stresses are applied to the 118 and the outer segment 116. In general, the inner segment 118 acts to overlap the bending moment and the compressive stress, and thus the inner segment 118 compared to the outer segment 116. ) More stress is generated.

Therefore, it is effective for stress distribution to keep the cross sectional area of the inner segment 118 the same as or larger than the cross sectional area of the outer segment 116. The same may be applied to the embodiment of FIGS. 7 to 9 in which the cross-sectional area of the inner segment 118 is made larger than that of the outer segment 116.

7A and 7B, the piston 110 is disposed between the inner segment 118 and the outer segment 116 of the piston 110, in which the head 112, the support 122, and the connecting segment 114 are provided. A rib 154 is formed around this central axis along the central axis of the. The rib 154 is provided on the piston 110 to reinforce the strength and to further distribute the stress.

8A and 8B, the piston 110 is connected between the inner segment 118 and the outer segment 116 of the connecting segment 114 connecting the head 112 and the support 122 of the piston 110. Ribs 156 are formed in a direction perpendicular to the central axis to improve durability of the piston 110.

In the embodiment of FIGS. 9A and 9B, the inner surfaces of each of the outer segment 116 and the inner segment 118 formed in the piston 110 have a half cylinder shape. As such, by making the inner surfaces of the outer and inner segments 116 and 118 have a semi-cylindrical shape, the vulnerability to the stresses generated at the edges of the segments 116 and 118 can be improved.

Since the bending moment acting during the compression stroke on the piston for use in the swash plate compressor according to the present invention is minimized, it is possible to prevent uneven wear of the piston and the cylinder bore, as well as to prevent deformation or breakage of the piston.

In addition, the mechanism for minimizing the bending moment of the swash plate compressor according to the present invention is to prevent the deflection of the swash plate to prevent the rolling or wear of the swash plate.

Since the stress due to the external force acting on the piston according to the present invention is effectively dispersed, it is possible to prevent deformation and breakage of the piston, thereby improving durability of the compressor.

Claims (10)

A piston disposed reciprocally in each of a plurality of cylinder bores, A cylindrical head; A half cylinder shaped outer segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A semicylindrical inner segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A recess having a pair of shoe pockets formed in the recess and connected to the head via the outer and inner segments; And Stress distribution means for preventing the piston from being changed or broken by dispersing the stress applied to the piston during the suction and compression stroke of the piston; The stress dispersing means is a piston for minimizing stress, characterized in that the thickness of the inner and outer segments are formed uniformly, and the cross-sectional area of the inner segment is larger than that of the outer segment. delete 2. The piston of claim 1, comprising a rib between the outer and inner segments passing through the central axis of the piston and having a cross section formed parallel to the outer and inner segments. The method of claim 1, wherein the cross-section between the outer and inner segments includes at least one rib formed integrally with the inner and outer segments in a direction perpendicular to the central axis of the piston. Piston for The piston of claim 1, wherein the inner surfaces of each of the outer and inner segments that are opposed to each other are formed in an arc shape having different center points. A stress distribution piston suitable for use in an air conditioner compressor in which a piston is reciprocally disposed in each of a plurality of cylinder bores, A cylindrical head; A half cylinder shaped outer segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A semicylindrical inner segment extending longitudinally from the head and having a thickness at all points less than the radius of the head; A recess, a support having a pair of pockets formed in the recess and connected to the head via the outer and inner segments; The inner segment allows the apex of the edge portion P and the head side shoe pocket to be formed on the same plane, thereby minimizing bending moment acting on the piston during compression stroke of the plurality of cylinder bores; And Stress dispersing means for distributing stress applied to the piston during suction and compression stroke of the piston in each of the cylinder bores; Including; The stress dispersing means is a piston for minimizing stress, characterized in that the thickness of the inner and outer segments are formed uniformly, and the cross-sectional area of the inner segment is larger than that of the outer segment. delete The piston for minimizing stress according to claim 6, wherein the stress distributing means passes through a central axis of the piston between the outer and inner segments and has a cross section parallel to the outer and inner segments. 7. The method of claim 6, wherein the stress distribution means comprises at least one rib whose cross section is integrally formed with the inner and outer segments in a direction perpendicular to the central axis of the piston between the outer and inner segments. Piston for minimizing stress. 7. The piston as claimed in claim 6, wherein the inner surfaces of each of the outer and inner segments which are opposed to each other are formed in an arc shape having different center points.

Images