Rotary Compressor and Equipment

Abstract

To provide a rotary compressor in which a cylindrical groove can be easily formed in a piston and the wear resistance between the piston and a vane is high, and an apparatus using this rotary compressor. 【Solution means】The compression mechanism section 30 has a cylinder 31, a piston 32 disposed in the cylinder 31, and a vane 33 that partitions the inside of the cylinder 31. The shaft 40 has an eccentric section 42. The cylinder 31 is formed with a vane groove 36 for disposing the vane 33. The eccentric section 42 is disposed in the cylinder 31. The piston 32 is fitted to the eccentric section 42. The piston 32 is formed with a cylindrical groove 32a having an arc angle α exceeding 180°. An end portion of the vane 33 is formed with a cylindrical section 33b disposed in the cylindrical groove 32a. The vane 33 operates without separating from the piston 32, and the Vickers hardness on the surface of the piston 32 is set to Hv400 or less.

Description

Technical Field

[0001] The present invention relates to a rotary compressor in which a vane operates without separating from a piston, and a device using this rotary compressor.

Background Art

[0002] Patent Document 1 discloses a rotary compressor in which a cylindrical groove is formed in a piston, and a cylindrical portion disposed in the cylindrical groove is formed at an end portion of a vane, so that the vane operates without separating from the piston. In addition, in order to achieve good slidability with the vane, the piston is subjected to a hardening treatment to increase the surface hardness by heat treatment or surface coating (Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] For a piston like the one described in Patent Document 1, it is not easy to form an arc-shaped groove on the outer peripheral portion of the hardened piston. In a hardened piston, the material structure may fall off from the piston surface during processing. In addition, the life of the tool used for processing the piston is reduced. Also, the processing time of the piston becomes extremely long. In a general rotary compressor, the vane that slides in the vane groove is subjected to a high-hardness surface treatment. When a vane with a high-hardness surface treatment slides on the piston, the piston sliding portion wears out in a piston that has not been hardened.

[0005] Therefore, an object of the present invention is to provide a rotary compressor in which a cylindrical groove can be easily formed in a piston and the wear resistance between the piston and a vane is high, and an apparatus using this rotary compressor.

Means for Solving the Problems

[0006] The rotary compressor 1 of the present invention according to claim 1 includes an electric motor unit 20 and a compression mechanism unit 30 in a sealed container 10. The electric motor unit 20 and the compression mechanism unit 30 are connected by a shaft 40. The compression mechanism unit 30 includes a cylinder 31, a piston 32 disposed in the cylinder 31, and a vane 33 that partitions the inside of the cylinder 31. The shaft 40 has an eccentric portion 42. The cylinder 31 is formed with a vane groove 36 for disposing the vane 33. The eccentric portion 42 is disposed in the cylinder 31. The piston 32 is fitted to the eccentric portion 42. The piston 32 is formed with a cylindrical groove 32a having an arc angle α exceeding 180°. An end portion of the vane 33 is formed with a cylindrical portion 33b disposed in the cylindrical groove 32a. The rotary compressor 1 is such that the vane 33 operates without separating from the piston 32, and a low-hardness material having a Vickers hardness of Hv400 or less on the surface of the piston 32 is used for the piston. engaging the cylindrical portion with a hard coating treatment on its surface in the cylindrical groove It is characterized by this. The present invention according to claim 2 is characterized in that, in the rotary compressor 1 according to claim 1, the piston 32 is made of a mouse cast iron material. The present invention according to claim 3 is characterized in that, in the rotary compressor 1 according to claim 1 or claim 2, a surface treatment is performed on a side surface of the vane 33, and the Vickers hardness on the side surface of the vane 33 exceeds Hv1000. The present invention according to claim 4 is characterized in that, in the rotary compressor 1 according to claim 3, the surface treatment is a nitriding treatment or a DLC treatment. The apparatus of the present invention according to claim 5 is an apparatus using the rotary compressor 1 according to claim 1 or claim 2, characterized in that the rotary compressor 1, a condenser 2, a decompression device 3, and an evaporator 4 are connected in a circular shape by piping.

Effects of the Invention

[0007] According to the present invention, by using a low-hardness material for the piston, it is easy to form a cylindrical groove, and the surface contact by the cylindrical portion and the cylindrical groove provides high wear resistance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0009] In the rotary compressor according to the first embodiment of the present invention, a low-hardness material having a Vickers hardness of Hv400 or less on the surface of the piston is used for the piston engaging a cylindrical portion with a hard coating treatment on its surface in a cylindrical groove That's what it is. According to this embodiment, by using a low-hardness material for the piston, it is easy to form a cylindrical groove, and the surface contact by the cylindrical portion and the cylindrical groove provides high wear resistance.

[0010] The second embodiment of the present invention is a rotary compressor according to the first embodiment, wherein the piston is made of a mouse cast iron material. According to this embodiment, it is easy to form a cylindrical groove.

[0011] The third embodiment of the present invention is a rotary compressor according to the first or second embodiment, wherein the side surface of the vane is surface-treated and the Vickers hardness on the side surface of the vane exceeds Hv1000. According to this embodiment, sufficient sliding resistance can be provided for the vane groove.

[0012] The fourth embodiment of the present invention is a rotary compressor according to the third embodiment, in which the surface treatment is nitriding treatment or DLC treatment. According to this embodiment, nitriding treatment or DLC treatment is suitable for the hard film treatment.

[0013] The device according to the fifth embodiment of the present invention is a device using the rotary compressor according to the first or second embodiment, in which the rotary compressor, the condenser, the decompression device, and the evaporator are annularly connected by piping. According to this embodiment, a highly reliable device can be provided.

Example

[0014] FIG. 1 is a cross-sectional view showing a rotary compressor according to an embodiment of the present invention, and FIG. 2 is a view taken along the line A-A shown in FIG. 1. The rotary compressor 1 according to this embodiment includes an electric motor part 20 and a compression mechanism part 30 in a sealed container 10. The electric motor part 20 and the compression mechanism part 30 are connected by a shaft 40. The electric motor part 20 is composed of a stator 21 fixed to the inner surface of the sealed container 10 and a rotor 22 that rotates within the stator 21. The compression mechanism part 30 has a cylinder 31, a piston 32 disposed within the cylinder 31, and a vane 33 (see FIG. 2) that partitions the inside of the cylinder 31. An upper bearing 51 is disposed on one surface of the cylinder 31, and a lower bearing 52 is disposed on the other surface of the cylinder 31. The shaft 40 is composed of a main shaft portion 41 to which the rotor 22 is attached and supported by the upper bearing 51, an eccentric portion 42 to which the piston 32 is attached, and a sub-shaft portion 43 supported by the lower bearing 52. The upper bearing 51 is fixed to the sealed container 10. The piston 32 is rotatably fitted to the eccentric portion 42 of the shaft 40 that penetrates the inside of the cylinder 31. An upper cover 53 is provided above the upper bearing 51. A soundproof chamber 54 is formed between the upper bearing 51 and the upper cover 53. The high-pressure refrigerant gas compressed by the compression mechanism part 30 is discharged into the soundproof chamber 54. The high-pressure refrigerant gas discharged into the soundproof chamber 54 is discharged into the sealed container 10.

[0015] At the bottom inside the closed container 10, an oil reservoir 11 is formed. The oil reservoir 11 stores refrigerating machine oil. Inside the shaft 40, an oil supply passage 46 inside the shaft is formed in the axial direction. Inside the eccentric portion 42, a communication passage 47 for supplying refrigerating machine oil to the sliding surface of the compression mechanism portion 30 is formed. The refrigerating machine oil in the oil reservoir 11 is introduced from the lower end of the shaft 40 into the oil supply passage 46 inside the shaft. A part of the refrigerating machine oil introduced into the oil supply passage 46 inside the shaft is supplied from the communication passage 47 to the sliding surface of the compression mechanism portion 30. An intake pipe 12 is connected to the side surface of the closed container 10, and a discharge pipe 13 is connected to the upper surface of the closed container 10. The intake pipe 12 guides the refrigerant to the compression mechanism portion 30. The discharge pipe 13 guides the refrigerant compressed by the compression mechanism portion 30 and discharged into the closed container 10 outside the closed container 10. An accumulator 14 is provided on the upstream side of the intake pipe 12.

[0016] In the rotary compressor 1 according to this embodiment, a condenser 2, a decompression device 3, and an evaporator 4 are connected annularly by pipes. The condenser 2 condenses the refrigerant discharged from the discharge pipe 13. The decompression device 3 decompresses the refrigerant condensed by the condenser 2. The evaporator 4 evaporates the refrigerant decompressed by the decompression device 3. The refrigerant evaporated by the evaporator 4 is returned to the accumulator 14. The accumulator 14 has an outer cylinder 14a, a refrigerant intake pipe 14b, and a separation plate 14c. At the upper part of the outer cylinder 14a, an outer cylinder inlet 14d for introducing the refrigerant from the evaporator 4 is provided. The refrigerant intake pipe 14b has an intake pipe inlet 14e inside the outer cylinder 14a. The separation plate 14c is disposed between the outer cylinder inlet 14d and the intake pipe inlet 14e A liquid reservoir portion 14f is formed at the inner bottom of the outer cylinder 14a. The liquid refrigerant is stored in the liquid reservoir portion 14f. The liquid refrigerant can be stored up to the height H of the intake pipe inlet 14e. Therefore, the volume up to the height H of the intake pipe inlet 14e is the volume of the liquid reservoir portion 14f. Note that the specific driving method of the rotary compressor 1 is not particularly limited. For example, the rotary compressor 1 may be driven by simple on-off control, or may be inverter-driven at a plurality of operating frequencies. In the case of inverter drive, in order to optimize the operation control of the rotary compressor 1, a low rotation region where the rotation speed of the electric motor unit 20 decreases, or a high rotation region where the rotation speed of the electric motor unit 20 increases occurs.

[0017] The compression chamber 34 shown in FIG. 2 is formed between the inner peripheral surface of the cylinder 31 and the outer peripheral surface of the piston 32 between the upper bearing 51 and the lower bearing 52. The suction pipe 12 is connected to the suction passage 35 of the compression mechanism unit 30. The suction passage 35 leads to the compression chamber 34. By the rotation of the shaft 40, the piston 32 performs a revolution motion. The vane 33 reciprocates in the vane groove 36 by the piston 32 revolving along the inner wall surface of the cylinder 31. The compression chamber 34 is partitioned by the vane 33 into a suction space 34a communicating with the suction passage 35 and a compression space 34b communicating with the discharge hole 37. The suction volume formed in the cylinder 31 is the volume of the suction space 34a in a state where the suction passage 35 is blocked by the piston 32, and is the volume in a state where the suction space 34a becomes the maximum space. Due to the revolution motion of the piston 32, the gas refrigerant sucked into the compression chamber 34 from the suction pipe 12 through the suction passage 35 is compressed in the compression chamber 34 and then discharged from the discharge hole 37 to the soundproof chamber 54. The refrigerant gas discharged into the soundproof chamber 54 is discharged into the sealed container 10 and then discharged from the discharge pipe 13 outside the sealed container 10. The high-pressure refrigerant gas discharged outside the sealed container 10 passes through the condenser 2, the decompression device 3, and the evaporator 4, becomes low-pressure refrigerant gas, and is returned to the compression mechanism unit 30 via the accumulator 14.

[0018] FIG. 3 is a diagram showing a piston and a vane used in the rotary compressor according to the embodiment. FIG. 3(a) is a perspective view with the piston and the vane separated, FIG. 3(b) is a plan view with the piston and the vane separated, and FIG. 3(c) is a perspective view of the vane viewed from different directions.

[0019] On the outer peripheral surface of the piston 32, a cylindrical groove 32a with an arc angle α exceeding 180° is formed. The cylindrical groove 32a extends from one end face of the piston 32 to the other end face. The vane 33 has a vane side surface portion 33a that slides in the vane groove 36, a cylindrical portion 33b disposed in the cylindrical groove 32a, and a constricted portion 33c that connects the vane side surface portion 33a and the cylindrical portion 33b. The cylindrical portion 33b is formed at the end of the vane 33. By engaging the cylindrical portion 33b with the cylindrical groove 32a, the vane 33 operates without separating from the piston 32. A notch portion 33d extending from one end face to the other end face of the cylindrical portion 33b is formed in the cylindrical portion 33b. The cylindrical portion 33b is divided into a plurality of arc surfaces 33e in the cylindrical portion 33b by the notch portion 33d. Thus, at least two separated arc surfaces 33e are formed on the outer peripheral surface of the cylindrical portion 33b by the notch portion 33d. Each arc surface 33e has an arc angle β less than 180°, and the notch portion 33d has an arc angle γ less than 45°. By setting the notch portion 33d to have an arc angle γ less than 45°, the contact area between the cylindrical groove 32a and the cylindrical portion 33b can be increased, and refrigerant leakage can be reliably prevented. In this embodiment, the notch 33d is formed at the vane tip of the vane 33. That is, the notch 33d is formed at the tip of the cylindrical portion 33b. Since it is difficult for a load to be applied to the vane tip, by forming the notch 33d at the vane tip, the suction-side arc surface 33e1 and the discharge-side arc surface 33e2 can be symmetrically formed by the notch 33d. Further, in this embodiment, the notch 33d is formed as a flat surface, but the notch 33d may be a curved surface as long as it is cut so as to be an inner surface rather than the arc-shaped outer peripheral surface of the cylindrical portion 33b, and it does not have to be formed of a single flat surface. It is preferable to arrange the two formed arc surfaces 33e at the position closest to the virtual extension surface X of the side surface of the vane side surface portion 33a. In this way, by having the point in the cylindrical portion 33b that is closest to the virtual extension surface X of the side surface of the vane side surface portion 33a on the arc surface 33e, refrigerant leakage can be reliably prevented.

[0020] The Vickers hardness on the surface of the piston 32 is set to Hv400 or less. By using a low-hardness material for the piston 32, it is easy to form the cylindrical groove 32a, and the wear resistance is also high due to the surface contact between the cylindrical portion 33b and the cylindrical groove 32a. The Vickers hardness on the surface of the piston 32 is preferably in the range of Hv80 to Hv400, and more preferably in the range of Hv180 to Hv250. It is preferable to use a gray cast iron material for the piston 32, and it is easy to form the cylindrical groove 32a by using a gray cast iron material.

[0021] Surface treatment is performed on the vane side surface portion 33a, that is, the side surface of the vane 33, and the side surface of the vane 33 has a hardness with a Vickers hardness exceeding Hv1000. Therefore, sufficient sliding resistance can be provided for the vane groove 36. Nitriding treatment or DLC treatment is suitable for the surface treatment of the vane side surface portion 33a. By performing nitriding treatment or DLC treatment, the vane side surface portion 33a can be subjected to a hard film treatment.

[0022] The surface hardness of at least a part of the cylindrical portion 33b is made lower than the surface hardness of the vane side surface portion 33a. Note that at least a part of the cylindrical portion 33b is the arc surface 33e. The same applies in the following description. By making the surface hardness of at least a part of the cylindrical portion 33b lower than the surface hardness of the vane side surface portion 33a, sliding resistance against the vane groove 36 is provided. Since the surface hardness of at least a part of the cylindrical portion 33b is lower than the surface hardness of the vane side surface portion 33a, the workability and toughness of the cylindrical portion 33b can be enhanced. It is preferable that the Vickers hardness of at least a part of the cylindrical portion 33b is Hv200 or more lower than the Vickers hardness of the vane side surface portion 33a. That is, by performing a hard film treatment on the vane side surface portion 33a, the Vickers hardness of the vane side surface portion 33a can be made Hv200 or more higher than the Vickers hardness of at least a part of the cylindrical portion 33b, and sufficient sliding resistance against the vane groove 36 can be provided. Also, the surface hardness of the constricted portion 33c is made lower than the surface hardness of the vane side surface portion 33a. Since the surface hardness of the constricted portion 33c is lower than the surface hardness of the vane side surface portion 33a, the workability and toughness of the constricted portion 33c can be enhanced. By making the surface hardness of the vane side surface portion 33a higher than the surface hardness of the constricted portion 33c, sliding resistance against the vane groove 36 can be provided. Note that the surface hardness of the constricted portion 33c is preferably made lower than the surface hardness of the cylindrical portion 33b. By making the surface hardness of the constricted portion 33c lower than the surface hardness of the vane side surface portion 33a and the cylindrical portion 33b, the workability and toughness of the constricted portion 33c can be enhanced. Also, the surface hardness of the arc surface 33e is preferably made lower than the surface hardness of the notch portion 33d. By making the surface hardness of the arc surface 33e lower than the surface hardness of the notch portion 33d, the workability and toughness of the arc surface 33e can be enhanced.

[0023] FIG. 4 is a diagram showing a manufacturing process of a vane used in the rotary compressor according to the same embodiment. Fig. 4(a) shows the base material of the vane 33. For the vane 33, an iron alloy mainly composed of iron (Fe) and containing chromium (Cr), or a steel material obtained by adding metal materials such as chromium (Cr), tungsten (W), vanadium (V), and molybdenum (Mo) to a high-carbon steel material is used. Fig. 4(b) shows the state in which the base material of the vane 33 shown in Fig. 4(a) is subjected to a hard coating treatment. As shown in Fig. 4(c), the base material of the vane 33 subjected to the hard coating treatment is fixed to the jig Y, and the cylindrical portion 33b and the constricted portion 33c are machined by the cutting tool Z. As shown in Fig. 4(c), in order to form the cylindrical portion 33b with an arc angle α exceeding 180°, it is necessary to perform finish machining in two or more steps, and the machining accuracy at the joint surface M of the machined surface decreases. However, by the notch portion 33d, the arc surface 33e in the cylindrical portion 33b is divided into a plurality of parts, and by setting each arc surface 33e to an arc angle β less than 180°, the machining accuracy of the arc surface 33e in the cylindrical portion 33b can be improved. In particular, by forming the notch portion 33d at the joint surface M, that is, the tip of the cylindrical portion 33b, the machining can be performed only by two finish machinings, namely, the finish machining for the suction-side arc surface 33e1 and the finish machining for the discharge-side arc surface 33e2.

[0024] The working fluid and the refrigerating machine oil described as the refrigerant in this embodiment are in a two-phase separation state under the temperature condition of 25°C. In this way, especially by using a refrigerating machine oil with low compatibility with the working fluid in the low rotation region of the rotary compressor 1, even when liquid compression operation cannot be avoided, the lubrication performance can be ensured and a good sliding state can be maintained. Here, the low rotation region is a rotation speed region of 900 rpm or less, particularly 600 rpm or less. In the low rotation region, liquid compression is likely to occur. By ensuring the lubrication performance in the low rotation region where liquid compression is likely to occur, the operation in the low rotation region, that is, the low-capacity operation, can be stably performed. In addition, in a temperature range from 0°C to 25°C, in a mixture in which a working fluid is maximally dissolved in a refrigerating machine oil, the proportion of the working fluid is 1 wt% or more and less than 30 wt%. Thus, by using a refrigerating machine oil with low compatibility with the working fluid, especially in a low rotation region, even when hydraulic compression operation is inevitable, lubrication performance can be ensured and a good sliding state can be maintained.

[0025] In this embodiment, the description has been given for a case where an accumulator 14 is provided upstream of the suction pipe 12, but the accumulator 14 can be eliminated. That is, by using a refrigerating machine oil with low compatibility with the working fluid, even when hydraulic compression operation is inevitable, lubrication performance by the refrigerating machine oil can be ensured and a good sliding state can be maintained, so that the accumulator 14 may not be provided. Also, the volume of the liquid storage portion 14f of the accumulator 14 can be set to be 2 times or less of the suction volume formed in the cylinder 31. That is, by using a refrigerating machine oil with low compatibility with the working fluid, even when hydraulic compression operation is inevitable, lubrication performance can be ensured and a good sliding state can be maintained, so that the accumulator 14 can be made smaller.

[0026] In particular, when the working fluid is R32 and the refrigerating machine oil is alkylbenzene oil, the compatibility is low, lubrication performance can be ensured, and a good sliding state can be maintained. Also, when the working fluid is carbon dioxide and the refrigerating machine oil is polyalkylene glycol oil, the compatibility is low, lubrication performance can be ensured, and a good sliding state can be maintained. Also, when the working fluid is R290 and the refrigerating machine oil is polyalkylene glycol oil, the compatibility is low, lubrication performance can be ensured, and a good sliding state can be maintained. Note that the refrigerating machine oil preferably has a kinematic viscosity of 35 mm / s or less.

[0027] The equipment in which the rotary compressor 1, the condenser 2, the decompression device 3, and the evaporator 4 according to this embodiment are annularly connected by pipes has high reliability.

Industrial Applicability

[0028] The equipment using the rotary compressor of the present invention is useful as a refrigeration cycle device such as a hot water heating device, an air conditioner, a water heater, a refrigerator, a showcase, a chiller, a dehumidifier, or a freezer.

Explanation of Signs

[0029] 1 Rotary compressor 2 Condenser 3 Pressure reducing device 4 Evaporator 10 Sealed container 11 Oil reservoir 12 Suction pipe 13 Discharge pipe 14 Accumulator 14a Outer cylinder 14b Refrigerant suction pipe 14c Separation plate 14d Outer cylinder inlet 14e Suction pipe inlet 14f Liquid reservoir part 20 Electric motor part 21 Stator 22 Rotor 30 Compression mechanism part 31 Cylinder 32 Piston 32a Cylindrical groove 33 Vane 33a Vane side surface part 33b Cylindrical part 33c Constriction part 33d Notch part 33e Arc surface 33e1 Suction side arc surface 33e2 Discharge side arc surface 34 Compression chamber 34a Suction space 34b Compression space 35 Suction passage 36 Vane groove 37 Discharge hole 40 Shaft 41 Main shaft part 42 Eccentric part 43 Sub-shaft part 46 Shaft internal oil supply passage 47 Communication passage 51 Upper bearing 52 Lower bearing 53 Upper cover 54 Soundproof chamber H Height M Connecting surface X Extended virtual surface Y Fixture Z Cutting tool α, β, γ Arc angle

Claims

1. A rotary compressor having an electric motor part and a compression mechanism part in a sealed container, wherein the electric motor part and the compression mechanism part are connected by a shaft, the compression mechanism part has a cylinder, a piston disposed in the cylinder, and a vane partitioning the inside of the cylinder, the shaft has an eccentric part, the cylinder is formed with a vane groove for disposing the vane, the eccentric part is disposed in the cylinder, the piston is fitted to the eccentric part, the piston is formed with a cylindrical groove having an arc angle exceeding 180°, a cylindrical part disposed in the cylindrical groove is formed at an end of the vane, and the vane operates without separating from the piston, wherein a low-hardness material with a Vickers hardness of 400 or less on the surface of the piston is used for the piston, and the cylindrical part having a hard film treatment on its surface is engaged with the cylindrical groove. A rotary compressor characterized by the above.

2. The rotary compressor according to claim 1, wherein the piston is made of a gray cast iron material.

3. The surface of the vane is surface-treated, and the Vickers hardness on the surface of the vane exceeds 1000. The rotary compressor according to claim 1 or claim 2, characterized by the above.

4. The surface treatment is a nitriding treatment or a DLC treatment. The rotary compressor according to claim 3, characterized by the above.

5. An apparatus using the rotary compressor according to claim 1 or claim 2, wherein the rotary compressor, a condenser, a decompression device, and an evaporator are connected annularly by pipes. An apparatus characterized by the above.

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