JP2018059434A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a load received by a compression mechanism from a crank shaft and inhibits burning of the compression mechanism.SOLUTION: A compression mechanism 15 has: a cylinder 24; a front head 23; a rear head 25; and a piston. The piston is installed in a cylinder hole having a cylindrical shape and connected with a crank shaft. The piston has a roller which revolves around a rotation axis 17g. The front head 23 has a first cylindrical through-hole 23d through which the crank shaft penetrates. The rear head 25 has a second cylindrical through-hole 25d through which the crank shaft penetrates. When the compression mechanism 15 is viewed along the rotation axis 17g, an angle between a first line segment and a second line segment is 90° to 180°. The first line segment connects a first center point 23f that is a center of the first through-hole 23d with a second center point 25f which is a center of the second through-hole 25d. The second line segment connects a top dead point of the piston with the first center point 23f.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a rotary compressor used in a refrigeration apparatus or the like.

  Conventionally, a rotary compressor as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 10-47278) is used as a compressor used in a refrigeration apparatus or the like. The rotary compressor includes a compression mechanism having a piston that rotates in a cylinder hole. The cylinder hole is a space surrounded by the cylinder and the pair of heads, and is a space where the refrigerant is compressed. The piston has, for example, a cylindrical roller and a blade formed integrally with the roller. In this case, the roller revolves while the blade held in the cylinder swings, whereby the refrigerant supplied to the cylinder hole is compressed.

  In the rotary compressor, the compression mechanism is disposed below the motor for driving the compression mechanism. The piston of the compression mechanism is connected to the rotor of the motor via a crankshaft. The pair of heads of the compression mechanism includes a front head that contacts the upper end surface of the cylinder and a rear head that contacts the lower end surface of the cylinder.

  The piston of the compression mechanism rotates as the motor rotates the crankshaft. At this time, the front head and the rear head slide with the rotating crankshaft. The rear head is located farther from the motor in the axial direction of the crankshaft than the front head. Therefore, when the rotating crankshaft is subjected to a horizontal load by the pressure of the refrigerant in the cylinder hole and the crankshaft is curved, the load that the rear head receives from the crankshaft is higher than the load that the front head receives from the crankshaft. Become. Further, since the area of the sliding surface of the rear head is smaller than the area of the sliding surface of the front head, the rear head is more susceptible to a load from the crankshaft than the front head. For this reason, the rear head is more likely to have problems such as seizure due to sliding with the crankshaft than the front head.

  The objective of this invention is providing the compressor which reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

  A compressor according to a first aspect of the present invention includes a casing, a compression mechanism, and a crankshaft. The compression mechanism is installed inside the casing and compresses the refrigerant. The crankshaft is installed inside the casing and rotates around the rotation axis. The compression mechanism includes a cylinder, a front head, a rear head, and a piston. The cylinder has a cylindrical cylinder hole. The front head contacts the upper end surface of the cylinder and supports the crankshaft. The rear head contacts the lower end surface of the cylinder and supports the crankshaft. The piston is installed in the cylinder hole and connected to the crankshaft. The piston has a cylindrical roller that revolves around a rotation axis. The front head has a cylindrical first through hole through which the crankshaft passes. The rear head has a cylindrical second through hole through which the crankshaft passes. When the compression mechanism is viewed along the rotation axis, the angle between the first line segment and the second line segment is 90 ° to 180 °. The first line segment connects a first center point that is the center of the first through hole and a second center point that is the center of the second through hole. The second line segment connects the center of the roller when the piston is at top dead center and the first center point.

  In this compressor, when the compression mechanism is viewed along the rotation axis, the position of the center (second center point) of the rear head is different from the position of the center (first center point) of the front head. That is, the rear head is eccentric with respect to the front head. During driving of the compression mechanism, the crankshaft is strongly pressed in a specific direction by the pressure of the refrigerant compressed in the cylinder hole. When the position of the top dead center of the piston is defined as 0 ° and the angle is defined along the rotation direction of the piston, the crankshaft is strongly pressed in the direction of 90 ° to 180 °. This is because the refrigerant immediately before being discharged from the compression mechanism exists in a range of 270 ° to 360 ° and applies a load toward the crankshaft. As a result, the load applied to the rear head from the crankshaft becomes maximum in the range of 90 ° to 180 °. Therefore, the load applied to the rear head is offset by decentering the rear head in the direction of 90 ° to 180 ° with respect to the front head. Reduced. Therefore, this compressor reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

  The compressor which concerns on the 2nd viewpoint of this invention is a compressor which concerns on a 1st viewpoint, Comprising: The angle between a 1st line segment and a 2nd line segment is 120 degrees-150 degrees.

  In this compressor, since the load applied to the rear head from the crankshaft becomes maximum particularly in the range of 120 ° to 150 °, the rear head is eccentric in the direction of 120 ° to 150 ° with respect to the front head. The load applied to is reduced. Therefore, this compressor reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

  The compressor concerning the 3rd viewpoint of the present invention is a compressor concerning the 1st viewpoint or the 2nd viewpoint, and the length of the 1st line segment is 0.05%-0.15% of the diameter of a crankshaft. It is.

  In this compressor, the size of the eccentricity of the rear head with respect to the front head is set on the basis of the diameter of the crankshaft in consideration of assembly variations of the compression mechanism. Thereby, the rear head can be appropriately eccentric with respect to the front head so that the load applied to the rear head is reduced. Therefore, this compressor reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

  The compressor which concerns on this invention reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

It is a longitudinal cross-sectional view of the rotary compressor 101 which concerns on embodiment. It is sectional drawing of the compression mechanism 15 in line segment II-II of FIG. 2 is an external view of a cylinder 24. FIG. The positional relationship between the front head 23 and the rear head 25 when the compression mechanism 15 is viewed along the rotation shaft 17g is shown. The positional relationship among the front head 23, the cylinder 24, and the rear head 25 when the compression mechanism 15 is viewed along the direction orthogonal to the rotation shaft 17g is shown. It is sectional drawing of the compression mechanism 15 when the piston 21 exists in a top dead center. 3 is a cross-sectional view of the compression mechanism 15 immediately before the refrigerant is discharged from the compression mechanism 15. FIG. The left object is a cylinder 24 and a rear head 25 of the conventional compression mechanism 15. The right object is the cylinder 24 and the rear head 25 of the compression mechanism 15 of the embodiment. FIG. 9 is an enlarged view of the vicinity of the second through hole 25d of the rear head 25 of the object on the left side of FIG. It is an enlarged view of the vicinity of the second through hole 25d of the rear head 25 of the object on the right side of FIG. Experimental results of measuring the degree of seizure of the rear head 25 using the direction of eccentricity of the rear head 25 (angle θ1 in FIG. 4) and the degree of eccentricity of the rear head 25 (length of the first line segment L1 in FIG. 4) as parameters. It is a graph showing. In Modification A, the position of the discharge port 23b when the compression mechanism 15 is viewed along the rotation shaft 17g is shown.

  A compressor according to an embodiment of the present invention will be described with reference to the drawings. The compressor is attached to a refrigerant circuit provided in a refrigeration apparatus such as an air conditioner. The compressor compresses the refrigerant gas flowing through the refrigerant circuit.

(1) Overall Configuration of Rotary Compressor The compressor of the present embodiment is a one-cylinder type and oscillating rotary compressor 101. FIG. 1 is a longitudinal sectional view of the rotary compressor 101. The rotary compressor 101 mainly includes a casing 10, a compression mechanism 15, a drive motor 16, a crankshaft 17, a suction pipe 19, and a discharge pipe 20. Next, each component of the rotary compressor 101 will be described.

(1-1) Casing The casing 10 includes a cylindrical body portion 11, a bowl-shaped top portion 12, and a bowl-shaped bottom portion 13. The top portion 12 is connected to the upper end portion of the body portion 11 in an airtight manner. The bottom 13 is connected to the lower end of the body 11 in an airtight manner.

  The casing 10 is formed of a rigid member that is unlikely to be deformed or damaged due to changes in pressure and temperature in the internal space and the external space of the casing 10. The casing 10 is installed so that the cylindrical axial direction of the trunk portion 11 is along the vertical direction. The lower part of the internal space of the casing 10 is an oil storage part 10a in which lubricating oil is stored. The lubricating oil is a refrigerating machine oil used for improving the lubricity of the sliding portion existing in the internal space of the casing 10.

  The casing 10 mainly accommodates a compression mechanism 15, a drive motor 16, and a crankshaft 17. The compression mechanism 15 is connected to the drive motor 16 via the crankshaft 17. The suction pipe 19 and the discharge pipe 20 are connected to the casing 10 in an airtight manner so as to penetrate the casing 10.

(1-2) Compression Mechanism FIG. 2 is a cross-sectional view of the compression mechanism 15 taken along line II-II in FIG. The compression mechanism 15 mainly includes a front head 23, a cylinder 24, a rear head 25, a piston 21, and a bush 22. The front head 23, the cylinder 24, and the rear head 25 are integrally fastened by bolts. The space above the compression mechanism 15 is a high-pressure space S1 from which the refrigerant compressed by the compression mechanism 15 is discharged.

  The compression mechanism 15 is immersed in the lubricating oil stored in the oil storage unit 10a. The lubricating oil in the oil reservoir 10a is supplied to the sliding portion of the compression mechanism 15 by differential pressure or the like. Next, each component of the compression mechanism 15 will be described.

(1-2-1) Cylinder FIG. 3 is an external view of the cylinder 24. The cylinder 24 mainly has a cylinder hole 24a, a suction hole 24b, a discharge notch 24c, a bush accommodation hole 24d, a blade accommodation hole 24e, and a heat insulation hole 24f. The cylinder 24 is connected to the front head 23 and the rear head 25. A first cylinder end surface 34 a that is an upper end surface of the cylinder 24 is in contact with the lower surface of the front head 23. The second cylinder end surface 34 b that is the lower end surface of the cylinder 24 is in contact with the upper surface of the rear head 25. The cylinder hole 24 a of the cylinder 24 is closed by the front head 23 and the rear head 25.

  The cylinder hole 24a is a cylindrical hole that penetrates the cylinder 24 in the vertical direction from the first cylinder end surface 34a to the second cylinder end surface 34b. The cylinder hole 24 a is a space surrounded by a cylinder inner peripheral surface 34 c that is an inner peripheral surface of the cylinder 24. The cylinder hole 24 a accommodates the eccentric shaft portion 17 a of the crankshaft 17 and the roller 21 a of the piston 21.

  The suction hole 24b is a hole penetrating along the radial direction of the cylinder 24 from the cylinder outer peripheral surface 34d, which is the outer peripheral surface of the cylinder 24, toward the cylinder inner peripheral surface 34c.

  The discharge cutout 24c is a space formed without penetrating the cylinder 24 in the vertical direction by cutting out a part of the cylinder inner peripheral surface 34c. The discharge notch 24c is formed on the first cylinder end surface 34a side.

  The bush housing hole 24d is a hole that is disposed between the suction hole 24b and the discharge notch 24c when the cylinder 24 is penetrated in the vertical direction and the cylinder 24 is viewed along the vertical direction. The bush housing hole 24d houses the blade 21b and the bush 22 of the piston 21.

  The blade accommodation hole 24e is a hole that penetrates the cylinder 24 in the vertical direction and communicates with the bush accommodation hole 24d.

  The heat insulating hole 24f is a hole that penetrates the cylinder 24 in the vertical direction between the cylinder outer peripheral surface 34d and the cylinder inner peripheral surface 34c. The cylinder 24 has a plurality of heat insulating holes 24f.

(1-2-2) Piston The piston 21 is inserted into the cylinder hole 24 a of the cylinder 24. The piston 21 includes a substantially cylindrical roller 21a and a blade 21b protruding outward in the radial direction of the roller 21a. The piston 21 is a member in which a roller 21a and a blade 21b are integrated. The first piston end surface 31 a that is the upper end surface of the piston 21 is in contact with the lower surface of the front head 23. The second piston end surface 31 b that is the lower end surface of the piston 21 is in contact with the upper surface of the rear head 25.

  The roller 21 a is inserted into the cylinder hole 24 a of the cylinder 24 while being fitted into the eccentric shaft portion 17 a of the crankshaft 17. Accordingly, the roller 21a performs a revolving motion around the rotation shaft 17g of the crankshaft 17 by the rotation of the crankshaft 17. The roller 21a revolves clockwise when the compression mechanism 15 is viewed from above.

  The blade portion 21b is accommodated in the bush accommodation hole 24d and the blade accommodation hole 24e of the cylinder 24. The blade portion 21b moves back and forth along the longitudinal direction while swinging.

  The compression mechanism 15 has a compression chamber 40 that is a space surrounded by the cylinder 24, the piston 21, the front head 23, and the rear head 25. The compression chamber 40 is partitioned by the piston 21 into a suction chamber 40a that communicates with the suction hole 24b and a discharge chamber 40b that communicates with the discharge notch 24c. In FIG. 2, the suction chamber 40 a and the discharge chamber 40 b are shown as regions surrounded by the cylinder inner peripheral surface 34 c and the piston outer peripheral surface 31 c that is the outer peripheral surface of the piston 21. The volumes of the suction chamber 40a and the discharge chamber 40b change according to the position of the piston 21.

(1-2-3) Bush The bush 22 is a pair of substantially semi-cylindrical members. The bush 22 is accommodated in the bush accommodating hole 24d of the cylinder 24 so as to sandwich the blade portion 21b of the piston 21. The bush 22 is slidable with the cylinder 24.

(1-2-4) Front Head The front head 23 is a member that covers the first cylinder end surface 34 a of the cylinder 24. The front head 23 has an upper bearing portion 23 a for supporting the crankshaft 17. The upper bearing portion 23a has a first through hole 23d that is a cylindrical hole that penetrates the front head 23 in the vertical direction. The first through hole 23d is a hole through which the crankshaft 17 passes. The front head 23 is fastened to the casing 10 with bolts or the like.

  The front head 23 has a discharge port 23b. The discharge port 23b is a cylindrical hole that penetrates the front head 23 in the vertical direction. The discharge port 23b communicates with the discharge notch 24c and the compression chamber 40 (discharge chamber 40b) on the lower side in the vertical direction. The discharge port 23b communicates with the high-pressure space S1 on the upper side in the vertical direction. The discharge port 23b is a flow path for sending the refrigerant compressed by the compression mechanism 15 from the discharge chamber 40b to the high-pressure space S1.

  A discharge valve 23 c that closes the discharge port 23 b is attached to the upper surface of the front head 23. The discharge valve 23c is a valve for preventing the reverse flow of the refrigerant from the high-pressure space S1 to the discharge chamber 40b. The discharge valve 23c is lifted upward by the pressure of the refrigerant inside the discharge port 23b. Thus, the discharge port 23b communicates with the high pressure space S1.

(1-2-5) Rear Head The rear head 25 is a member that covers the second cylinder end surface 34 b of the cylinder 24. The rear head 25 has a lower bearing portion 25 a for supporting the crankshaft 17. The lower bearing portion 25a has a second through hole 25d that is a cylindrical hole that penetrates the rear head 25 in the vertical direction. The second through hole 25d is a hole through which the crankshaft 17 passes.

(1-3) Drive Motor The drive motor 16 is a brushless DC motor housed in the casing 10 and installed above the compression mechanism 15. The drive motor 16 mainly includes a stator 51 that is fixed to the inner wall surface of the casing 10 and a rotor 52 that is rotatably accommodated by providing an air gap inside the stator 51.

  The stator 51 includes a stator core 61 and a pair of insulators 62 attached to both end surfaces of the stator core 61 in the vertical direction. Stator core 61 has a cylindrical portion and a plurality of teeth (not shown) protruding radially inward from the inner peripheral surface of the cylindrical portion. A conductive wire is wound around the teeth of the stator core 61 together with the pair of insulators 62. Thus, a coil 72 a is formed on each tooth of the stator core 61.

  The outer surface of the stator 51 is provided with a plurality of core cut portions (not shown) that are notched from the upper end surface to the lower end surface of the stator 51 and at a predetermined interval in the circumferential direction. . The core cut part forms a motor cooling passage extending in the vertical direction between the body part 11 and the stator 51.

  The rotor 52 is composed of a plurality of metal plates stacked in the vertical direction. The rotor 52 is connected to the crankshaft 17 that passes through the center of rotation in the vertical direction. The rotor 52 is connected to the compression mechanism 15 via the crankshaft 17.

  The rotor 52 includes a rotor core 52a composed of a plurality of metal plates stacked in the vertical direction, and a plurality of magnets 52b embedded in the rotor core 52a. The magnets 52b are arranged at equal intervals along the circumferential direction of the rotor core 52a.

(1-4) Crankshaft The crankshaft 17 is accommodated in the casing 10 and is disposed such that its axial direction is along the vertical direction. The crankshaft 17 is connected to the rotor 52 of the drive motor 16 and the piston 21 of the compression mechanism 15. The crankshaft 17 has an eccentric shaft portion 17a. The eccentric shaft portion 17 a is connected to the roller 21 a of the piston 21 that is inserted into the cylinder hole 24 a of the cylinder 24. The upper end of the crankshaft 17 is connected to the rotor 52 of the drive motor 16. The crankshaft 17 is supported by the upper bearing portion 23 a of the front head 23 and the lower bearing portion 25 a of the rear head 25. The crankshaft 17 rotates about the rotating shaft 17g. The rotating crankshaft 17 slides with the inner peripheral surface of the upper bearing portion 23 a of the front head 23 and the inner peripheral surface of the lower bearing portion 25 a of the rear head 25.

(1-5) Suction Pipe The suction pipe 19 is a pipe that penetrates the trunk portion 11 of the casing 10. An end of the suction pipe 19 inside the casing 10 is fitted in the suction hole 24 b of the cylinder 24. The end of the suction pipe 19 outside the casing 10 is connected to the refrigerant circuit. The suction pipe 19 is a pipe for supplying a refrigerant from the refrigerant circuit to the compression mechanism 15.

(1-6) Discharge Pipe The discharge pipe 20 is a pipe that penetrates the top 12 of the casing 10. An end portion of the discharge pipe 20 inside the casing 10 is located in a space above the drive motor 16. The end of the discharge pipe 20 outside the casing 10 is connected to the refrigerant circuit. The discharge pipe 20 is a pipe for supplying the refrigerant compressed by the compression mechanism 15 to the refrigerant circuit.

(2) Detailed Configuration of Rotary Compressor Next, a detailed configuration of the compression mechanism 15 will be described. FIG. 4 shows the positional relationship between the front head 23 and the rear head 25 when the compression mechanism 15 is viewed along the rotation shaft 17g. FIG. 4 shows only the upper bearing portion 23 a of the front head 23 and the lower bearing portion 25 a of the rear head 25. FIG. 5 shows a positional relationship among the front head 23, the cylinder 24, and the rear head 25 when the compression mechanism 15 is viewed along a direction orthogonal to the rotation shaft 17g.

  FIG. 4 shows the first line segment L1 and the second line segment L2. The first line segment L1 includes a first center point 23f that is the center of the first through hole 23d of the front head 23 and a second through hole 25d of the rear head 25 when the compression mechanism 15 is viewed along the rotation shaft 17g. To the second center point 25f, which is the center of. The second line segment L2 includes a third center point 21f, which is the center of the roller 21a when the piston 21 is at the top dead center, and a first center point 23f when the compression mechanism 15 is viewed along the rotation shaft 17g. Tie with. The top dead center of the piston 21 is the position of the piston 21 when the blade portion 21b of the piston 21 enters the deepest part of the bush accommodation hole 24d. FIG. 6 is a cross-sectional view of the compression mechanism 15 when the piston 21 is at the top dead center. Hereinafter, an angle increasing along the rotation direction of the piston 21 is defined with the position of the top dead center of the piston 21 being 0 °. This angle corresponds to the rotation angle of the piston 21. In FIG. 2, the rotation angle of the piston 21 is 180 °. In FIG. 6, the rotation angle of the piston 21 is 0 °.

  As shown in FIG. 4, the first line segment L1 is a line segment connecting the first center point 23f and the second center point 25f. Therefore, when the compression mechanism 15 is viewed along the rotation shaft 17g, the second center point 25f is at a position different from the first center point 23f. That is, the rear head 25 is eccentric with respect to the front head 23. The direction of eccentricity of the rear head 25 is represented by an angle θ1 between the first line segment L1 and the second line segment L2 when the compression mechanism 15 is viewed along the rotation shaft 17g. The angle θ1 is an angle between the first line segment L1 and the second line segment L2 measured on the rotation direction side of the piston 21 with the second line segment L2 as a reference. The angle θ1 between the first line segment L1 and the second line segment L2 is 90 ° to 180 °.

  In FIG. 4, the length of the first line segment L <b> 1 represents the degree of eccentricity of the rear head 25 with respect to the front head 23. The length of the first line segment L1 is set to 0.05% to 0.15% of the diameter of the crankshaft 17. For example, when the diameter of the crankshaft 17 is 20 mm, the length of the first line segment L1 is set to 10 μm to 30 μm. In FIGS. 4 and 5, the degree of eccentricity of the rear head 25 (the length of the first line segment L1) is shown more emphasized than the actual one. The diameter of the crankshaft 17 is a circular diameter when the crankshaft 17 is cut in a direction orthogonal to the rotating shaft 17g.

(3) Operation of Rotary Compressor The operation of the rotary compressor 101 will be described. When the drive motor 16 is started, the eccentric shaft portion 17a of the crankshaft 17 rotates eccentrically about the rotation shaft 17g of the crankshaft 17. Thereby, the roller 21a of the piston 21 connected to the eccentric shaft portion 17a revolves in the cylinder hole 24a of the cylinder 24. While the roller 21a revolves, the piston outer peripheral surface 31c is in contact with the cylinder inner peripheral surface 34c. Due to the revolution of the roller 21 a, the blade 21 b of the piston 21 moves forward and backward while being sandwiched between the bushes 22 on both sides.

  Along with the revolution of the roller 21a, the compression chamber 40 (suction chamber 40a) communicating with the suction hole 24b gradually increases in volume. At this time, a low-pressure refrigerant flows into the suction chamber 40a from the outside of the casing 10 via the suction pipe 19. Along with the revolution of the roller 21a, the suction chamber 40a becomes a discharge chamber 40b communicating with the discharge notch 24c, and the discharge chamber 40b gradually decreases in volume and becomes the suction chamber 40a again. Thereby, the low-pressure refrigerant sucked into the suction chamber 40a from the suction pipe 19 via the suction hole 24b is compressed in the compression chamber 40 (discharge chamber 40b). The high-pressure refrigerant compressed in the discharge chamber 40b is discharged into the high-pressure space S1 via the discharge notch 24c and the discharge port 23b. The refrigerant discharged into the high-pressure space S1 passes through the motor cooling passage of the drive motor 16 and flows upward, and is then discharged from the discharge pipe 20 to the outside of the casing 10.

(4) Features of the Rotary Compressor In the rotary compressor 101, as shown in FIG. 4, the position of the center (second center point 25f) of the rear head 25 when the compression mechanism 15 is viewed along the rotation shaft 17g. Is different from the position of the center of the front head 23 (first center point 23f). That is, the rear head 25 is eccentric with respect to the front head 23.

  FIG. 7 is a cross-sectional view of the compression mechanism 15 immediately before the refrigerant is discharged from the compression mechanism 15. In FIG. 7, the rotation angle of the piston 21 is about 270 °. As shown in FIG. 7, the refrigerant immediately before being discharged from the compression mechanism 15 exists in the discharge chamber 40b in the range of 270 ° to 360 °. At this time, since the pressure in the discharge chamber 40b is higher than the pressure in the suction chamber 40a, the refrigerant in the discharge chamber 40b applies a load to the crankshaft 17 through the roller 21a. Since the discharge chamber 40b is in the range of 270 ° to 360 °, the crankshaft 17 is loaded in the direction of 90 ° to 180 ° on the opposite side of the discharge chamber 40b with respect to the rotating shaft 17g. That is, during driving of the compression mechanism 15, the crankshaft 17 is pressed in the direction of 90 ° to 180 ° by the pressure of the refrigerant compressed in the cylinder hole 24a. In FIG. 7, the load applied to the crankshaft 17 in the direction of 135 ° is indicated by an arrow.

  Further, the rear head 25 is located farther from the drive motor 16 in the direction of the rotation shaft 17g than the front head 23. Therefore, when the crankshaft 17 that is rotating is subjected to a horizontal load due to the pressure of the refrigerant compressed in the cylinder hole 24a and the crankshaft 17 is bent, the horizontal direction of the crankshaft 17 at the height position of the rear head 25 is increased. The displacement is larger than the horizontal displacement of the crankshaft 17 at the height position of the front head 23. Therefore, in the compression mechanism 15, the load received by the rear head 25 from the crankshaft 17 can be reduced by decentering the rear head 25 with respect to the front head 23 along the direction of the load applied to the crankshaft 17 by the compressed refrigerant. it can. In FIG. 4, the rear head 25 is eccentric with respect to the front head 23 in the direction of 135 °.

  In the compression mechanism 15, the load applied to the rear head 25 from the crankshaft 17 becomes the maximum in the range of 90 ° to 180 °. Therefore, the rear head 25 is eccentric in the direction of 90 ° to 180 ° with respect to the front head 23. The load applied to the rear head 25 is reduced. When the rear head 25 is not eccentric with respect to the front head 23, the inner peripheral surface of the second through hole 25d of the rear head 25 may be seized by a load received from the rotating crankshaft 17. Therefore, the rotary compressor 101 reduces the load that the compression mechanism 15 receives from the crankshaft 17 and suppresses the seizure of the compression mechanism 15. In particular, when the pressure in the discharge chamber 40b is abnormally increased due to a failure of the compression mechanism 15, the load received by the compression mechanism 15 from the crankshaft 17 is reduced, so that seizure of the compression mechanism 15 is effectively suppressed. .

  In the rotary compressor 101, the eccentric dimension of the rear head 25 with respect to the front head 23 is set based on the diameter of the crankshaft 17 in consideration of assembly variations of the compression mechanism 15. The eccentric dimension of the rear head 25 is the length of the first line segment L1 shown in FIG. By setting the eccentric dimension of the rear head 25 based on the diameter of the crankshaft 17, the rear head 25 can be appropriately eccentric with respect to the front head 23 so that the load applied to the rear head 25 is reduced. Therefore, the rotary compressor 101 reduces the load that the compression mechanism 15 receives from the crankshaft 17 and suppresses the seizure of the compression mechanism 15.

(5) Example Next, the conventional compression mechanism 15 in which the rear head 25 is not eccentric with respect to the front head 23 and the compression mechanism 15 of the embodiment in which the rear head 25 is eccentric with respect to the front head 23 were used. The experimental results will be described with reference to the photographs shown in FIGS. The object on the left side of FIG. 8 is the cylinder 24 and the rear head 25 of the conventional compression mechanism 15. The object on the right side of FIG. 8 is the cylinder 24 and the rear head 25 of the compression mechanism 15 of the embodiment. The cylinder 24 is placed on the rear head 25. The central hole is the second through hole 25 d of the rear head 25. FIG. 9 is an enlarged view of the vicinity of the second through hole 25d of the rear head 25 of the left object of FIG. FIG. 10 is an enlarged view of the vicinity of the second through hole 25d of the rear head 25 of the object on the right side of FIG. Each of the two rear heads 25 shown in FIG. 8 is in a state of sliding with the crankshaft 17 for a long time. The diameter of the crankshaft 17 is 20 mm. For the object on the right side of FIG. 8, the direction of eccentricity of the rear head 25 (angle θ1 in FIG. 4) is 135 °, and the degree of eccentricity of the rear head 25 (the length of the first line segment L1 in FIG. 4) is 20 μm. It is.

  As shown in FIG. 9, in the conventional compression mechanism 15 in which the rear head 25 is not eccentric with respect to the front head 23, the inner periphery of the second through hole 25 d of the rear head 25 slides with the crankshaft 17. The sliding trace which is a crack resulting from is formed. On the other hand, as shown in FIG. 10, in the compression mechanism 15 of the embodiment in which the rear head 25 is eccentric with respect to the front head 23, sliding marks are formed on the inner peripheral surface of the second through hole 25 d of the rear head 25. Not. Therefore, it has been confirmed that by decentering the rear head 25 with respect to the front head 23, the load received by the rear head 25 from the crankshaft 17 is reduced, and the bearing strength of the rear head 25 is improved.

  FIG. 11 shows the degree of seizure of the rear head 25 using the direction of eccentricity of the rear head 25 (angle θ1 in FIG. 4) and the degree of eccentricity of the rear head 25 (length of the first line segment L1 in FIG. 4) as parameters. It is a graph showing the experimental result measured. In FIG. 11, the intersection point O of the graph axes is a first center point 23 f that is the center of the first through hole 23 d of the front head 23. In FIG. 11, the angle representing the direction of eccentricity of the rear head 25 is assumed to increase clockwise with the direction upward from the intersection O being 0 °. In FIG. 11, a circle having a radius of 20 μm centering on the intersection point O is indicated by a dotted line.

  In FIG. 11, points indicated by “◯”, “Δ”, and “x” represent the position of the second center point 25 f that is the center of the second through hole 25 d of the rear head 25. That is, a line segment connecting the intersection point O representing the first center point 23f and each point representing the second center point 25f corresponds to the first line segment L1 in FIG. For each point representing the second center point 25f, “◯” represents the case where seizure and abnormal wear of the rear head 25 were not observed, and “Δ” was slight seizure and abnormal wear of the rear head 25 observed. “X” represents a case where seizure and abnormal wear of the rear head 25 are clearly observed.

  As shown in FIG. 11, when the direction of the eccentricity of the rear head 25 is 90 ° to 180 °, seizure and abnormal wear of the rear head 25 were not observed. In addition, when the rear head 25 is hardly decentered with respect to the front head 23, slight seizure and abnormal wear of the rear head 25 were observed. Further, when the direction of eccentricity of the rear head 25 is 270 ° to 360 °, seizure and abnormal wear of the rear head 25 were clearly observed. From these experimental results, it was confirmed that the load applied to the rear head 25 is reduced and the seizure of the rear head 25 is suppressed by decentering the rear head 25 in the direction of 90 ° to 180 ° with respect to the front head 23. .

(6) Modification (6-1) Modification A
In the embodiment, when the compression mechanism 15 is viewed along the rotation shaft 17g, the angle θ1 between the first line segment L1 and the second line segment L2 is 90 ° to 180 °. However, the angle θ1 between the first line segment L1 and the second line segment L2 is preferably 120 ° to 150 °. The load applied to the rear head 25 from the crankshaft 17 tends to become maximum especially in the range of 120 ° to 150 °. Is effectively reduced.

(6-2) Modification B
In the rotary compressor 101 of the embodiment, the cause of the load applied to the rear head 25 is the load applied to the crankshaft 17 by the high-pressure refrigerant existing in the discharge chamber 40b. The high-pressure refrigerant existing in the discharge chamber 40 b passes through the discharge port 23 b of the front head 23 and is discharged into the high-pressure space S 1 outside the compression mechanism 15. Therefore, the position of the discharge port 23 b restricts the position of the discharge chamber 40 b where the refrigerant immediately before being discharged from the compression mechanism 15 exists, and affects the direction of the load applied to the crankshaft 17.

  FIG. 12 is a view similar to FIG. 4 and shows the second line segment L2 and the third line segment L3 when the compression mechanism 15 is viewed along the rotation shaft 17g. The second line segment L2 connects the first center point 23f and the third center point 21f. The third line segment L3 connects the center position of the discharge port 23b in the circumferential direction of the cylinder hole 24a and the first center point 23f. When the compression mechanism 15 is viewed along the rotation axis 17g, the angle θ2 between the third line segment L3 and the second line segment L2 is 270 ° to 360 °. The angle θ <b> 2 is an angle between the third line segment L <b> 3 and the second line segment L <b> 2 measured on the rotation direction side of the piston 21 with the second line segment L <b> 2 as a reference.

  In the rotary compressor 101, as shown in FIG. 12, the discharge port 23b through which the refrigerant discharged from the compression mechanism 15 passes is formed so that its center is located in the range of 270 ° to 360 °. That is, the discharge chamber 40b in which the refrigerant immediately before being discharged from the compression mechanism 15 exists is generally in the range of 270 ° to 360 °. Therefore, the refrigerant present in the discharge chamber 40 b applies a load toward the crankshaft 17 in the direction of 90 ° to 180 °. Therefore, the load applied from the crankshaft 17 to the rear head 25 becomes the maximum in the range of 90 ° to 180 °. Therefore, the load applied to the rear head 25 is reduced by decentering the rear head 25 in the direction of 90 ° to 180 ° with respect to the front head 23.

  Further, in this modification, when the compression mechanism 15 is viewed along the rotation axis 17g, the angle θ2 between the third line segment L3 and the second line segment L2 is 340 ° to 350 °. preferable. When the discharge port 23b is formed in the range of 340 ° to 350 °, the pressure of the refrigerant in the discharge chamber 40b is the highest immediately before the discharge valve 23c is opened. At this time, the discharge chamber 40b is generally in the range of 300 ° to 330 °. Therefore, the load applied from the crankshaft 17 to the rear head 25 becomes the maximum in the range of 120 ° to 150 ° as in the modification A. In this case, the load applied to the rear head 25 is effectively reduced by decentering the rear head 25 in the direction of 120 ° to 150 ° with respect to the front head 23.

(6-3) Modification C
In the embodiment, the rotary compressor 101 is a one-cylinder type rotary compressor. However, the rotary compressor 101 may be a two-cylinder type rotary compressor.

  The compressor which concerns on this invention reduces the load which a compression mechanism receives from a crankshaft, and suppresses the burning of a compression mechanism.

DESCRIPTION OF SYMBOLS 10 Casing 15 Compression mechanism 17 Crankshaft 17g Rotating shaft 21 Piston 21a Roller 23 Front head 23b Discharge port 23d 1st through-hole 23f 1st center point 24 Cylinder 24a Cylinder hole 25 Rear head 25d 2nd through-hole 25f 2nd center point 101 Rotary Compressor (Compressor)
L1 1st line segment L2 2nd line segment L3 3rd line segment

Japanese Patent Laid-Open No. 10-47278

Claims (3)

A casing (10);
A compression mechanism (15) installed inside the casing and compressing the refrigerant;
A crankshaft (17) installed inside the casing and rotating about a rotation axis (17g);
With
The compression mechanism is
A cylinder (24) having a cylindrical cylinder hole (24a);
A front head (23) in contact with the upper end surface of the cylinder and supporting the crankshaft;
A rear head (25) that contacts the lower end surface of the cylinder and supports the crankshaft;
A piston (21) installed in the cylinder hole, connected to the crankshaft, and having a cylindrical roller (21a) revolving around the rotation axis;
Have
The front head has a cylindrical first through hole (23d) through which the crankshaft passes,
The rear head has a cylindrical second through hole (25d) through which the crankshaft passes,
When the compression mechanism is viewed along the rotation axis, a first center point (23f) that is the center of the first through hole and a second center point (25f) that is the center of the second through hole are obtained. The angle between the first line segment (L1) to be connected and the second line segment (L2) to connect the center of the roller and the first center point when the piston is at top dead center is 90 ° to 180 °,
Compressor (101). The angle between the first line segment and the second line segment is 120 ° to 150 °.
The compressor according to claim 1. The length of the first line segment is 0.05% to 0.15% of the diameter of the crankshaft.
The compressor according to claim 1 or 2.