[Name of Document]

DESCRIPTION

[Title of Invention]

ROTARY COMPRESSOR

[Technical Field]

[0001]
The present disclosure relates to a rotary compressor used in a refrigeration apparatus, an air-conditioning apparatus, and a hot water apparatus and the like.

Background Art

[0002]
A rotary compressor, such as a rotary compressor with two cylinders used in an air-conditioning apparatus, has upper and lower cylinders, upper and lower rollers, upper and lower bearings, and a partition plate, in which the two cylinders are disposed on the upper side and lower side with the partition plate therebetween. Additionally, the two cylinders each has an eccentric portion of a crankshaft inserted therein in which the eccentric portions are arranged 180 degrees out of phase to each other. The upper and lower rollers are fitted to respective eccentric portions allowing eccentric motion. Further, the two cylinders each has a slidable vane inserted therein in which each vane divides a space formed between the cylinder and the roller into a compression chamber and a suction chamber. Each of the vanes is pressed to the roller with energizing means. Furthermore, the rotary compressor is made to compress a refrigerant sucked into the compression chamber with the roller rotating and sliding in the cylinder.

[0003]
In addition, there is a rotary compressor with two cylinders that aims to improve wear resistance and lubricity to sliding between the roller and the partition plate, which is in contact with the roller, while the rotary compressor is undergoing a high velocity/high load operation by applying phosphate coating or nitrocarburizing treatment to the surface of the partition plates separating the two compression chambers (see, for example, Patent Literature 1).

[0004]
Further, there is a rotary compressor with two cylinders that prevents seizure and wear of a partition plate, in which a roller rotates and slides, by performing phosphate coating to the opposing faces of the partition plate and the roller, and, furthermore, performing molybdenum disulfide coating treatment, which is excellent in its load bearing, lubricant oil retention, and initial conformability, over the above to cover the waviness and unevenness of the surface of the partition plate and to compensate for the machining accuracy (see, for example, Patent Literature 2).

[0005]
Furthermore, there is a rotary compressor with two cylinders that prevents seizure and wear of a crankshaft and a main and sub bearing even when the oil surface of the oil sump has dropped due to refrigerant foaming during startup and after liquid return operation by performing induction hardening to the crankshaft--the crankshaft that is provided with a roller and that rotates and slides the roller in a cylinder by rotating itself— and to create a difference in surface hardness between the main and sub bearings (see, for example, Patent Literature 3).

[Citation List] [Patent Literature]

[0006]
[Patent Literature 1] Japanese Unexamined Patent Application Publication > No. 2-123294 (page 4 upper right column lines 14 to 19)

[Patent Literature 2] Japanese Unexamined Patent Application Publication No. 10-9168 (paragraph [0010], Fig. 1)

[Patent Literature 3] Japanese Unexamined Patent Application Publication No. 2008-38787 (paragraph [0029] and [0030], Fig. 3) [Summary of Invention] [Technical Problem]

[0007]
Due to spread of compressors equipped with an inverter that is capable of variable control of operational rotation speed, present refrigeration apparatuses are capable of performing efficient cooling or heating even when in a state in which the temperature difference between the outdoor air and indoor air is small by operating the compressor with low rotation speed.

[0008]
Further, due to increasing awareness towards energy saving, the end-user side is reducing the amount of power consumed by setting the indoor temperature settings to a temperature close to the temperature of the outdoor air temperature when cooling or heating with the refrigeration apparatus.

[0009]
Thus, in recent years, frequency of operation of the compressor under low rotation speed has increased, and there is an increased tendency of frequently starting and stopping the compressor intermittently under low rotation speed.

[0010]
In a rotary compressor, lubricant oil is supplied from the oil sump such that the lubricant oil in the oil sump is sucked up through the oil distribution channel provided in the crankshaft with the rotation of the crankshaft when the crankshaft is compressing the refrigerant. In a lubricant oil supply channel connected to a partition plate and a lubricant oil supply channel connected to a bearing, there are spaces of different volume that are made during assembling of a compression mechanism. Among these spaces, the space that has been made in the lubricant oil supply channel connected to the partition plate is lager in volume than the lubricant oil supply channel connected to the bearing. This is due to the need to form a hole in the partition plate that is disposed between the upper and lower cylinders, a hole in which an eccentric portion of the crankshaft (larger diameter than the main shaft unit of the crankshaft) can pass therethrough during assembly. Therefore, during startup of the compressor, due to the volume difference between the spaces in the compression mechanism, supply of lubricant oil to the partition plate is late compared to the bearing side, and, thus, the lubricity of the partition plate is relatively poor compared to the bearing and the partition plate and is susceptible to wear.

[0011]
Further, during low speed operation in which the crankshaft is made to continually rotate in a low rotation speed, the amount of lubricant oil that is sucked up from the oil sump through an oil distribution channel reduces, and the amount of lubricant oil supplied to the sliding member in the compression mechanism, such as the main and sub bearings, rollers, vanes, and the partition plate, drops.

[0012]
Furthermore, in compressors with a partition plate that has been heat treated to improve the wear and abrasion resistance of the partition plate, since the heat treatment requires a lot of processing steps and requires much processing time, cost is increased.

[0013]
A technical problem of the present disclosure is to prevent galling and seizure of a partition plate by reducing, with an inexpensive method, wear associated with deterioration of lubricity of the partition plate during low speed operation and wear associated with deterioration of lubricity of the partition plate caused by a volume difference between spaces existing in a lubricant oil supply channel connected to the partition plate and in a lubricant oil supply channel connected to the bearings. Solution to Problem

[0014]
The rotary compressor according to the present disclosure is constituted as described below. That is, the rotary compressor includes a compression mechanism and a motor unit that drives the compression mechanism, which are contained in a hermetic vessel; the compression mechanism having a crankshaft having a plurality of eccentric portions; a plurality of cylinders respectively disposed with the eccentric portions of the crankshaft; a partition plate disposed between two of the cylinders and sandwiched by these cylinders; a plurality of rollers disposed in the cylinders, the rollers each being inserted with the corresponding eccentric portion of the crankshaft; a main bearing and a sub bearing, into which the crankshaft inserted, disposed at both ends of the stacked cylinders and partition plate ; and a plurality of vanes each partitioning an enclosed space into a compression chamber and a suction chamber, the enclosed space including a space enclosed by the cylinders, the main bearing, the partition plate, and the rollers, and a space enclosed by the cylinders, the sub bearing, the partition plate, and the rollers, in which with a rotation of the crankshaft, repetition of suction and compression of a fluid is carried out by rotation of the rollers in the cylinders, and heat treatment is performed to the partition plate so as to provide a difference in hardness such that the hardness of the partition plate is greater than the hardness of the main bearing and the sub bearing.

Advantageous Effects of Invention

[0015]
In the rotary compressor according to the present disclosure, since the partition plate is provided with heat treatment and is provided with a difference in hardness such that the hardness of the partition plate is greater than the hardness of the main bearing and sub bearing, wear associated with deterioration of lubricity of the partition plate during low speed operation in which the amount of lubricant oil supply is low and the lubricant oil supplied to the partition plate is late compared to the main and sub bearings and wear associated with deterioration of lubricity of the partition plate caused by the lagging supply of the lubricant oil to the partition plate due to the volume difference between spaces existing in the lubricant oil supply channel connected to the partition plate and in the lubricant oil supply channel connected to the bearings can be reduced with an inexpensive method. Accordingly, galling and seizure of the partition plate can be prevented and reliability can be increased.

[Brief Description of Drawings]

[0016]
[Fig. 1] Fig. 1 is a longitudinal sectional view illustrating a general configuration of a rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 2] Fig. 2 is a diagram illustrating an assembling process of a compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 3] Fig. 3 is a diagram illustrating an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 4] Fig. 4 is a diagram illustrating an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 5] Fig. 5 is a diagram illustrating an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 6] Fig. 6 is a diagram illustrating an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 7] Fig. 7 is a diagram illustrating an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 8] Fig. 8 is a diagram illustrating an oil distribution channel of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 9] Fig. 9 is an enlarged, detail view of a main section of Fig. 8.

[Fig. 10] Fig. 10 is a longitudinal sectional view illustrating the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[Fig. 11] Fig. 11 is an explanatory drawing of an operation of a compression mechanism of a rotary compressor according to Embodiment 2 of the present disclosure.

[Fig. 12] Fig. 12 is a diagram illustrating, by means of hatching, frictional areas of slide members of the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure, in which (a) depicts a frictional area of a roller and (b) depicts a frictional area of a partition plate to the roller.

[Fig. 13] Fig. 13 is a diagram illustrating, by means of hatching, frictional areas of slide members of the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure, in which (a) depicts a frictional area of a vane and (b) depicts a frictional area of a partition plate and a main and sub bearing to the vane.

[Fig. 14] Fig. 14 is a longitudinal sectional view illustrating the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure.

[Fig. 15] Fig. 15 is a longitudinal sectional view illustrating a main section of a comparative example of a rotary compressor.

[Fig. 16] Fig. 16 is a longitudinal sectional view illustrating a main section of a comparative example of a rotary compressor.

[Description of Embodiments]

[0017]
As mentioned previously, due to the spread of compressors equipped with an inverter, present refrigeration apparatuses are capable of variable control of the operational rotation speed. Accordingly, present refrigeration apparatuses are capable of performing cooling and heating with high efficiency even when the temperature difference of the indoor air and the outdoor air is small in range by operating in a low rotation speed.

[0018]
Furthermore, in the present refrigeration apparatus, during an operation in practical use, there is a lot of time period in which operation is carried out in the low rotation speed region, in which there is little temperature difference between the outdoor air and indoor air and in which a small capacity of the compressor is required. Accordingly, evaluation of refrigeration apparatuses are carried out based on an energy efficiency indicator that agrees with that during practical use. That is, for an energy efficiency indicator of an refrigeration apparatus, from the energy efficiency COP that has been conventionally adopted and that is an average efficiency value of rated cooling and rated heating, an year-round energy efficiency APF is adopted that considers, in addition to the rated cooling and rated heating, the efficiency while the compressor is rotated at a low rotation speed during cooling and heating (medium cooling, medium heating) corresponding to partial loads in seasons, such as the spring and fall, which is a period with relatively mild climate.

[0019]
Furthermore, awareness towards energy saving has increased on the end-user side, and in order to drop the amount of power consumed, the room temperature setting is set high during cooling and is set low during heating. Because the amount of power consumed is being reduced, the frequency of the compressor operated in a temperature range having little difference to the outdoor air temperature has increased. Thus, operating time of the compressor under low rotation speed is increased, frequency of starting and stopping under low rotation speed is increased, and starting and stopping is carried out intermittently.

[0020]

Embodiment 1
Subsequently, a rotary compressor according to Embodiment 1 of the present disclosure will be described in detail. Note that a rotary compressor with two cylinders that is used in air-conditioning apparatuses will be described as an example. Fig. 1 is a longitudinal sectional view illustrating a general configuration of the rotary compressor according to Embodiment 1 of the present disclosure.

[0021]
As in Fig. 1, the rotary compressor according to Embodiment 1 of the present disclosure contains in a hermetic vessel 1, a compression mechanism 100, and a motor unit 200 that drives the compression mechanism 100. In the bottom portion of the hermetic vessel, lubricant oil is stored. The motor unit includes a stator 2 and a rotor 3. A crankshaft 4 is fitted in the rotor. The crankshaft 4 includes a main shaft unit 4a and a sub shaft unit 4b, and in the main shaft unit 4a and sub shaft unit 4b, a main shaft side eccentric portion 4c and sub shaft side eccentric portion 4d is formed, respectively, having a phase difference of 180 degrees.

[0022]
The compression mechanism 100 includes a partition plate 9, and an upper cylinder 7 and a lower cylinder disposed on the upper side and lower side of the partition plate 9 such that the partition plate 9 is between the cylinders. The crankshaft 4 is inserted in the partition plate 9 that is disposed between the upper cylinder 7 and the lower cylinder 8, and its main shaft side eccentric portion 4c and its sub shaft side eccentric portion 4d is disposed in the upper cylinder 7 and the lower cylinder 8, respectively. Further, a middle shaft unit 4e between the main shaft side eccentric portion 4c and sub shaft side eccentric portion 4d in the crankshaft 4 is disposed in the partition plate 9. Furthermore, the compression mechanism 100 has in the main shaft side eccentric portion 4c and the sub shaft side eccentric portion 4d, an upper roller 10 and a lower roller 11 fitted respectively therein. The upper roller 10 and the lower roller 11 are allowed to perform an eccentric rotational motion in the upper cylinder 7 and lower cylinder 8, respectively. Additionally, the compression mechanism 100 has in the upper cylinder 7 and lower cylinder 8, an upper vane 12 and a lower vane 13 inserted slidably and respectively therein. These upper and lower vanes 12 and 13 are pressed, at all times, to the upper roller 10 and lower roller 11, respectively, with energizing means 31 and 32 constituted by a coil spring. The upper and lower vanes 12 and 13 each has a function of partitioning the space formed between the upper and lower cylinders 7 and 8 and the upper and lower rollers 10 and 11, respectively, into a compression chamber and a suction chamber. Furthermore, on the sides of the stacked upper and lower cylinders 7 and 8 and the partition plate 9, a main bearing 5 and a sub bearing 6 supporting the crankshaft 4 are disposed. The upper and lower cylinders 7 and 8, the partition plate 9, and the main bearing 5 and the sub bearing 6 are integrally fastened with two types of bolts 14 and 15 with different lengths.

[0023]
In the rotary compressor according to Embodiment 1 of the present disclosure configured as above, the upper roller 10 and the lower roller 11 rotate and slide in the upper cylinder 7 and lower cylinder 8, respectively, with the rotation of the rotor 3. This allows the refrigerant gas to be sucked into the compression chamber through a suction pipe 41, and the refrigerant sucked into the compression chamber is compressed. The compressed high-pressure refrigerant gas is discharged into the hermetic vessel 1, and is discharged out of the hermetic vessel 1 through a discharge pipe 42.

[0024]
In addition, the rotary compressor according to the present disclosure is configured such that the partition plate 9 is provided with heat treatment (quench hardening) and that the hardness of the partition plate 9 is greater than the hardness of the main bearing 5 and the sub bearing 6. Since a difference in hardness is provided such that the hardness of the partition plate 9 is greater than the hardness of the main bearing 5 and the sub bearing 6, the wear and abrasion resistance of the partition plate 9 can be made better than that of the main bearing 5 and the sub bearing 6.

[0025]
This allows the amount of wear of the partition plate 9 to be reduced even when the amount of lubricant oil supply is low, and even when the lubricant oil supplied to the partition plate 9 is late compared to the main and sub bearings 5 and 6, the lubricant oil which is supplied to the upper and lower rollers 10 and 11, the upper and lower vanes 12 and 13, the main and sub bearings 5 and 6, and the partition plate 9 in the compression mechanism 100. Accordingly, galling and seizure of the partition plate 9 can be prevented and reliability can be increased.

[0026]
As mentioned above, since the partition plate 9 is provided with quench hardening and since the wear and abrasion resistance of the partition plate 9 is higher than that of the main and sub bearings 5 and 6, machining cost can be suppressed and the amount of wear of the partition plate 9 can be reduced.

[0027]
Subsequently, an assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure will be described. Figs. 2 to Fig. 7 all illustrate the assembling process of the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[0028]
(1) As shown in Fig. 2, first, the upper cylinder 7 and the main bearing 5 are fixed fastened by short bolts 15. A plurality of bolts 15 is used.

[0029]
(2) As shown in Fig. 3, the main shaft unit 4a of the crankshaft 4 is inserted to the main bearing 5 from the upper cylinder 7 side. Next, the upper roller 10 is fitted to the outer side of the crankshaft 4, is made to pass through the outer side of the sub shaft unit 4b, the sub shaft side eccentric portion 4d, and the middle shaft unit 4e, in this order, and is assembled into the main shaft side eccentric portion 4c. At this time, the upper vane 12 (Fig. 1) is incorporated into the upper cylinder 7.

[0030]
(3) As shown in Fig. 4, the partition plate 9 that has increased wear and abrasion resistance with the heat treatment (quench hardening) is fitted to the outer side of the crankshaft 4, is made to pass through the outer side of the sub shaft unit 4b and the sub shaft side eccentric portion 4d, in this order, and is assembled into the middle shaft unit 4e. In this state, as shown by the arrow, since the partition plate 9 is only made to pass through the outer side of the sub shaft side eccentric portion 4d and is shifted to the shaft direction, the center of the partition plate 9 and the upper cylinder 7 does not agree with each other.

[0031]
(4) As shown in Fig. 5, the partition plate 9 is shifted to a direction orthogonal to the shaft and is set so that the center agrees with that of the upper cylinder 7. This is done so that the position of a bolt run-through hole 9b provided in the partition plate 9, a bolt run-through hole 7a of the upper cylinder 7, and a bolt run-through hole 5a of the main bearing 5 are in alignment and so that the bolt, which will be mentioned later, can be inserted therethrough.

[0032]
(5) As shown in Fig. 6, the lower roller 11 is fitted to the outer side of the crankshaft 4, is made to pass through the sub shaft unit 4b and is assembled into the sub shaft side eccentric portion 4d.

[0033]
(6) Furthermore, the lower cylinder 8 and the sub bearing 6 is fixed with the bolts 15 (plural in number), and the lower vane 13 (Fig. 1) is incorporated into the lower cylinder 8. This is fitted to the outer side of the sub shaft unit 4b of the crankshaft 4.

[0034]
(7) As shown in Fig. 7, having the partition plate 9 in between, the lower cylinder 8 is fixed to the upper cylinder 7 with long bolts 14 (plural in number) from the outside of the sub bearing 6. Furthermore, at the same time, having the partition plate 9 in between, the upper cylinder 7 is fixed to the lower cylinder 8 with long bolts 14 (plural in number) from the outside of the main bearing 5.

[0035]
Subsequently, an oil distribution channel of the rotary compressor according to Embodiment 1 of the present disclosure will be described. Fig. 8 is a diagram illustrating the oil distribution channel of the rotary compressor according to Embodiment 1 of the present disclosure. Fig. 9 is an enlarged, detail view of a main section of Fig. 8. Fig. 10 is a longitudinal sectional view illustrating the compression mechanism of the rotary compressor according to Embodiment 1 of the present disclosure.

[0036]
Because the compression mechanism 100 is assembled as above (1) to (7), the compressor mechanism 100 has therein a space A (Fig. 7) between the partition plate 9 and the middle shaft unit 4e. Further, a space B (hereinafter, referred to as "B1") between the upper roller 10, the main shaft side eccentric portion 4c, and the main bearing 5 is formed. Furthermore, a space B (hereinafter, referred to as "B2") between the lower roller 11, the sub shaft side eccentric portion 4d, and the sub bearing 6 is also formed. Here, the volume of space A is larger than the volumes of spaces B1 and B2. This is due to the need to form a hole in the partition plate 9, which is disposed between the upper and lower cylinders 7 and 8; a hole for the partition plate 9 to pass through the outer side of the eccentric portion of the crankshaft (larger diameter than the main shaft unit of the crankshaft) during the assembly process (3) mentioned above.

[0037]
The supply of lubricant oil to the compression mechanism 100 of the rotary compressor according to Embodiment 1 of the present disclosure is performed by the lubricant oil distributed through the oil distribution channel of the crankshaft 4 from the oil sump 30 in the bottom of the compressor, and by centrifugal lubrication from oil supply holes 16, 17, 18, and 19 caused by the rotation of the crankshaft 4. Accordingly, the amount of supplied oil increases in proportion to the rotation speed and the rotational frequency of the crankshaft 4. During an operation with low rotation speed, the amount of lubricant oil supplied to the compression mechanism 100 drops.

[0038]
As in Figs. 8 to 10, supply of oil to the upper and lower rollers 10 and 11 and the main and sub bearings 5 and 6 are performed by distributing the oil into respective spaces B1 and B2 from the oil supply holes 16 and 17 provided in the main and sub bearings 5 and 6 through channels C1 and C2, and by distributing the oil into space B1 an B2 from the oil supply holes 18 and 19 through channels D1 and D2. Supply of oil to the partition plate 9 and the upper and lower rollers 10 and 11 are performed by distributing the oil into space A from the oil supply holes 18 and 9 through channels E and F. Accordingly, the supply of lubricant oil to the partition plate 9 and the main and sub bearings 5 and 6 will be poor until space A and spaces B1 and B2 are filled with lubricant oil. That is to say, space A and spaces B1 and B2 act as constraints on the supply of lubricant oil to the partition plate 9 and the main and sub bearings 5 and 6.

[0039]
As mentioned previously, the space A formed between the partition plate 9 and the middle shaft unit 4e is larger than spaces B1 and B2 that is formed between the upper and lower rollers 10 and 11, the main and sub bearings 5 and 6, and the main and sub shaft side eccentric portions 4c and 4d. Accordingly, the supply of lubricant oil to the partition plate 9 will be late compared to that of the main and sub bearings 5 and 6. Thus, when start and stop is carried out intermittently under operation of low rotation speed in which supply of lubricant oil is low, the lubricity of the partition plate 9 is relatively hindered compared to the main and sub bearings 5 and 6, and is more susceptible to wear.

[0040]
However, the rotary compressor according to Embodiment 1 of the present disclosure employs a partition plate 9 that has improved wear and abrasion resistance by heat treatment (quench hardening), and, thus, even if there is a large space A formed between the partition plate 9 and the middle shaft unit 4e, progression of wear is slow. Accordingly, the rotary compressor according to Embodiment 1 of the present disclosure is particularly effective to rotary compressors equipped with a compression mechanism that has a large space A, which is inherently a constraint for the supply of lubricant oil, in the lubricant oil supply channel. As will be described later, enlargement of space A facilitates assembly of the compression mechanism and is effective in miniaturizing the compression mechanism. Furthermore, in such a compressor, the durability of the partition plate 9 is increased and longer product life can be achieved.

[0041]
Without considering the existence of the sub shaft side eccentric portion 4d, assuming that the inside diameter of the partition plate 9 is equal to the outside diameter of the middle shaft unit 4e of the crankshaft 4, in order to rotate the crankshaft 4 without the partition plate 9 and the middle shaft unit 4e coming in contact with each other, the assembly needs to be performed with high precision centering.

[0042]
Further, as a method of making space A between the partition plate 9 and the middle shaft unit 4e of the crankshaft 4 small, for example, dividing the partition plate 9 into two having a split-into-halves configuration may be considered. This method will be described with reference to Figs. 15 and 16. Figs. 15 and 16 are both longitudinal sectional views illustrating a main section of a comparative example of a rotary compressor. As illustrated in Figs. 15 and 16, there is an assembly method in which the partition plate 9 is split into two half-split partition plates 9L and 9R, which are sandwiched between the upper and lower cylinders 7 and 8 in the middle shaft unit 4e of the crankshaft 4. However, even when this splitting and combining assembly method is carried out, which requires no high precision centering, play (gap) between the inside diameter of the partition plate 9 and the outside diameter of the middle shaft unit 4e needs to be provided in order to enable assembly of the inside diameter of the partition plate 9 and the outside diameter of the middle shaft unit 4e to not come in contact with each other.

[0043]
As is the case with the rotary compressor according to Embodiment 1 of the present disclosure, if the inside diameter of the partition plate 9 is larger than the outside diameter of the sub shaft side eccentric portion 4d, space A will become large as a result, but it will be possible to fit the partition plate 9 to the outer side of the crankshaft 4 and to pass the partition plate 9 through the. outside of the sub shaft side eccentric portion 4d (Figs. 4 and 5). Accordingly, assembly without the crankshaft 4 coming in contact with the middle shaft unit 4e is facilitated.

[0044]
A typical characteristic of a rotary compressor with a plurality of cylinders is that the clearance between the bearings, that is, between the main bearing and the sub bearing, is large, and as a result, the deflection angle of the eccentric portion of the crankshaft becomes large during operation. In order to reduce this, it is preferable that the clearance between the bearings is made small to the extent possible.

[0045]
As shown in Fig. 3, in order to fit the upper roller 10 to the outer side of the sub shaft unit 4b and to pass the upper roller 10 to the main shaft side eccentric portion 4c without being caught in the shaft direction, the length of the middle shaft unit 4e in the shaft direction needs to be longer than the length of the upper roller 10 in the shaft direction, and the upper roller 10 needs to be able to shift itself in the direction orthogonal to the shaft after passing through the sub shaft side eccentric portion 4d. In the rotary compressor according to Embodiment 1 of the present disclosure, the length of the main shaft side eccentric portion 4c and the sub shaft side eccentric portion 4d in the shaft direction is shortened towards the partition plate 9 side, as shown in Fig. 6, while not changing the length of the upper and lower rollers 10 and 11 in the shaft direction and while maintaining the length of the middle shaft unit 4e in the shaft direction so as to correspond to the length of the rollers. With the above configuration, although above-described spaces B1 and B2 are formed (Fig. 7), the overall length of the crankshaft 4 can be restrained, and the length of the middle shaft unit 4e in the shaft direction can be relatively long compared to the length of the upper roller 10 in the shaft direction. Thus, it will be possible to assemble a compact compression mechanism 100.

[0046]
Incidentally, as a method of reducing the clearance between the bearings, a method of reducing the length of the middle shaft unit 4e in the shaft direction, that is, the thickness of the partition plate 9 in the shaft direction as thin as possible while keeping it longer than the length of the upper roller 10 in the shaft direction may be considered. For compactness and resource saving, it is desired that the partition plate is thin to the extent possible. However, if the partition plate is made thin, then deformation of the partition plate becomes large, the deformation caused by the difference of pressure in the compression chambers on both sides of the partition plate when the timing of the pressure rise in each of the chambers is different. Accordingly, the partition plate will have more tendencies to come in contact with the rollers and vanes.

[0047]
Conventional techniques dealing with this are, as mentioned above, providing surface treatment to either of the partition plate, rollers, main and sub bearings, or the crankshaft, which are sliding components, or enhancing the surface hardness in order to prevent wear and seizure.

[0048]
In the process of providing surface treatment to the partition plate, first, in order to improve the adhesion of the chemical agent that will be the surface film, a degreasing process and washing are carried out to remove the oil on the surface of the subject matter. Next, in order to increase affinity with the chemical agent, surface preparation such as phosphate film formation is performed, and after washing again, surface coating process with molybdenum disulfide or the like is performed. The process is completed after drying has been performed. As described above, surface treatment has many processing steps and long machining time, and thus increases cost.

[0049]
On the other hand, the rotary compressor according to Embodiment 1 of the present disclosure improves wear and abrasion resistance by performing quench hardening to the partition plate 9. The quench hardening process can be performed by heat treatment in a high-temp-furnace and cooling, and thus the required steps are fewer than that of the surface treatment, and it will be possible to improve wear and abrasion resistance in a short time with low cost.

[0050]
It should be noted that although the wear of the partition plate 9 is reduced by allowing the partition plate 9 to have a difference in hardness compared to the main and sub bearings 5a and 6, that is, by configuring the hardness of the partition plate to be greater than that of the main and sub bearings 5 and 6, the wear of the upper and lower roller or the upper or lower vanes 12 and 13 may be reduced instead. Method for this will be described in Embodiment 2.

[0051]

Embodiment 2
In rotary compressors, frictional areas of rollers and vanes, which will be described subsequently, are smaller compared to the frictional areas of bearings and partition plates. Accordingly, material with greater hardness compared to bearings and partition plates are used in rollers and vanes. In order to reduce wear of the rollers and vanes, the hardness of the partition plate in which heat treatment has been performed needs to be lower in hardness compared to the rollers and vanes. By performing heat treatment to the partition plate so that the hardness increases in the order of rollers and vanes > partition plate bearings, the wear of the roller and vanes can be reduced, as well as the wear of the partition plate.

The a->b-»c-»din Fig. 11 is an exemplary diagram of an operation of a compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure, and illustrates situations in the compression mechanism while upper and lower rollers rotate. As shown in Fig. 11, upper and lower rollers 10A and 11A slide with eccentric rotational motions in upper and lower cylinders 7 and 8 in between the partition plate and main and sub bearings. Upper and lower vanes 12A and 13A slides with reciprocating motions.

[0052]
Fig. 12 is a diagram illustrating, by means of hatching, frictional areas of slide members of the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure, in which (a) depicts a frictional area of the upper and lower rollers and (b) depicts a frictional area of the partition plate to the single rotation of the upper and lower rollers. As in Fig. 12 (a) and (b), the frictional area of the upper and lower rollers 10A and 11A are smaller than the frictional area of the partition plate 9 during a single rotation of the upper and lower rollers 10A and 11 A. Thus, the upper and lower rollers 10A and 11A slide in a more concentrated manner than the partition plate 9.

[0053]
Fig. 13 is a diagram illustrating, by means of hatching, frictional areas of slide members of the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure, in which (a) depicts a frictional area of upper and lower vanes and (b) depicts a frictional area of a partition plate and a main and sub bearing to the upper and lower vanes. As in Fig. 13 (a) and (b), the frictional area of the upper and lower vanes 12A and 13A are smaller than the frictional area of the partition plate 9 and main and sub bearings 5 and 6. Thus, the upper and lower vanes 12A and 13A slide in a more concentrated manner than the partition plate 9 and the main and sub bearings 5 and 6.

[0054]
That is, if the upper and lower rollers 10A and 11A and the upper and lower vanes 12A and 13A have the same hardness to the partition plate 9 and the main and sub bearings 5 and 6 when compared to those of the partition plate 9 and the main and sub bearings 5 and 6, they are susceptible to wear. If the hardness of the partition plate 9 is made greater than the upper and lower rollers 10A and 11A and the upper and lower vanes 12A and 13A, before the partition plate 9, the upper and lower rollers 10A and 11A and the upper and lower vanes 12A and 13A will wear.

[0055]
Fig. 14 is a longitudinal sectional view illustrating the compression mechanism of the rotary compressor according to Embodiment 2 of the present disclosure. In the rotary compressor according to Embodiment 2 of the present disclosure, as shown in Fig. 14, the partition plate 9, the upper and lower rollers 10A and 11 A, and the upper and lower vanes 12A and 13A have been performed with heat treatment (quench hardening) thereto, and a difference in hardness increases in the order: upper and lower rollers and upper and lower vanes > partition plate > main and sub bearings.

[0056]
Typically, as a compressor bearing, ones with gray cast iron or sintering is widely used due to its availability, workability, and cost. As for their hardness, for example, those about HRB 65 to 110 (HRC 0 to 30) are typically used. Furthermore, as for the vanes and rollers, those with great hardness composed of stainless steel, cast iron of NiCrMo are typically used. As for their hardness, for example, those about HRC 45 to 70 are typically used. Accordingly, it is preferable that the hardness of the partition plate be in the range of HRC 30 to 45.

Here, the hardness of the main and sub bearings 5 and 6, the partition plate 9, the upper and lower rollers 10A and 11 A, and the upper and lower vanes 12A and 13A are set in ranges as below.

* Main and sub bearings 5 and 6: Rockwell B-Scale HRB 65 to 110 (equivalent to HRC 0 to 30)

* Partition plate: Rockwell C-Scale HRC 30 to 40

* Upper and lower rollers: Rockwell C-Scale HRC 45 to 55

* Upper and lower vanes: Rockwell C-Scale HRC 55 to 70

[0057]
As aforedescribed, in the rotary compressor according to Embodiment 2 of the present disclosure, the partition plate 9, the upper and lower rollers 10A and 11 A, and the upper and lower vanes 12A and 13A have been performed with heat treatment (quench hardening) thereto, and a difference in hardness increases in the order: upper and lower rollers and upper and lower vanes > partition plate > main and sub bearings. Accordingly, the wear of the partition plate due to the sliding can be reduced more compared to the wear of the main and sub bearings due to the sliding. Furthermore, the wear of the upper and lower rollers 10A and 11A and the upper and lower vanes 12A and 13A due to the sliding can be reduced more compared to the wear of the partition plate 9 due to the sliding. Reference Signs List

[0058]
1. hermetic vessel; 2. stator; 3. rotor; 4. crankshaft; 4a. main shaft unit; 4b. sub shaft unit; 4c. main shaft side eccentric portion; 4d. sub shaft side eccentric portion; 4e. middle shaft unit; 5. main bearing; 5a, 7a, 9b. bolt run-through hole; 6. sub bearing; 7. upper cylinder; 8. lower cylinder; 9. partition plate; 10, 10A. upper roller; 11, 11 A. lower roller; 12, 12A. upper vane; 13, 13A. lower vane; 14, 15. bolt; 16, 17, 18, 19. oil supply hole; 30. oil sump; 31, 32. energizing means; 41. suction pipe; 42. discharge pipe; 100. compression mechanism; 200. motor unit; A, B, B1, B2. space; C1, C2, D1, D2, E channel.

[Name of document]

CLAIMS

[Claim 1]

A rotary compressor, comprising:

a compression mechanism and a motor unit that drives the compression mechanism, which are contained in a hermetic vessel, wherein the compression mechanism includes

a crankshaft having a plurality of eccentric portions, a plurality of cylinders respectively disposed with the eccentric portions of the crankshaft,

a partition plate disposed between the cylinders and sandwiched by these cylinders,

a plurality of rollers disposed in the cylinders, the rollers each being inserted with the corresponding eccentric portion of the crankshaft, a main bearing and a sub bearing, into which the crankshaft inserts, disposed at both ends of the stacked cylinders and partition plate, and

a plurality of vanes each partitioning an enclosed space into a compression chamber and a suction chamber, the enclosed space including a space enclosed by the cylinders, the main bearing, the partition plate, and the rollers, and a space enclosed by the cylinders, the sub bearing, the partition plate, and the rollers, wherein

by way of rotation of the crankshaft, repetition of suction and compression of a fluid is carried out with rotation of the rollers in the cylinders, and heat treatment is performed to the partition plate so as to provide a difference in hardness such that the hardness of the partition plate is greater than the hardness of the main bearing and the sub bearing.

[Claim 2]
The rotary compressor of claim 1, wherein heat treatments are performed to the rollers and the vanes so as to provide a difference in hardness such that the hardness of the rollers and the vanes are greater than the hardness of the partition plate.

[Claim 3]
The rotary compressor of claim 1 or 2, wherein a space (A) formed between the crankshaft and the partition plate that is fitted on the outer side of the crankshaft is larger than a space (B) each formed between the rollers, the main bearing, the sub bearing, and the eccentric portions.