JPH07189956A - Multiple cylinder rotary compressor - Google Patents

Abstract

PURPOSE:To alleviate eccentric abutment of a drive shaft against a bearing on a side of a front head or the contact of a rotor of a motor with a stator so as to reduce vibration in a multiple cylinder rotary compressor. CONSTITUTION:A pressure receiving area by compressed gas of a roller 52 housed inside a cylinder 5 on a side of a front head 8 is set smaller than that by compressed gas of a roller 62 housed inside a cylinder 6 on a side of a rear head 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder rotary compressor, and more particularly to at least two cylinders, in which rollers provided in each cylinder are eccentrically rotated by eccentric parts formed on a drive shaft and having different eccentric directions. The present invention relates to a multi-cylinder rotary compressor.

[0002]

2. Description of the Related Art Conventionally, as a multi-cylinder rotary compressor,
For example, the one described in JP-A-3-222888 is known. That is, the multi-cylinder rotary compressor, as shown in FIG.
A motor B including a stator B1 and a rotor B2 is provided, and a drive shaft C coupled to the rotor B2 is provided on the lower side thereof.
The compression element D driven by
Is a two-cylinder type, that is, it is provided with upper and lower two first and second cylinders E and F, and between the cylinders E and F, the cylinder chambers E1 and F formed in the cylinders E and F are formed.
A middle plate G defining 1 is interposed, and front and rear heads H and J are provided above and below the cylinders E and F, respectively.
Bearings H1 and J1 extending in the vertical direction are integrally provided at the central portions of the heads H and J, and the drive shaft C is supported by the bearings H1 and J1. On the other hand, first and second eccentric portions C1 and C2 having opposite eccentric directions are respectively formed at two upper and lower positions between the support portions of the respective bearing portions H1 and J1 of the drive shaft C, and these eccentricities are respectively formed. The parts C1 and C2 are fitted into the rollers E2 and F2 arranged in the cylinder chambers E1 and F1. The cylinders E and F have the same height, and the cylinder chambers E1 and F1 have the same inner diameter and the same volume, and the rollers E2 and F2 have the same outer diameter. The rollers E2 and F2 have the same height and are eccentrically rotated in the cylinder chambers E1 and F1 so that the fluid gas of the same volume is alternately compressed and discharged into the casing A. . Further, each of the cylinders E,
The blades L and M are urged so that they are always in contact with a part of the outer peripheral surfaces of the rollers E2 and F2 via a spring K.
Is provided.

[0003]

By the way, according to the above rotary compressor, since the lower side of the second eccentric portion C2 of the drive shaft C is supported only by the bearing portion J1 of the rear head J, the length is short. On the other hand, since the upper side of the first eccentric portion C1 of the drive shaft C is formed to be long so as to be coupled to the rotor B2 of the motor B, each of the drive shaft C is driven by the drive shaft C. The rollers E2 and F2 are connected to the cylinder chambers E1 and F1 in the first and second cylinders E and F, respectively.
When the fluid gas is compressed by being eccentrically rotated by, the rollers E2, F2 and the eccentric portions C1, C2 are compressed by the compressed gas.
Since a load in the orthogonal direction is applied to the drive shaft C via the drive shaft C, the drive shaft C is bent, and the drive shaft C is bent above the first eccentric portion C1 having a long shaft length. The side is large, and as will be described later, there is a large difference in the bending amount of the shaft between when the fluid gas is compressed in the first cylinder E and when the fluid gas is compressed in the second cylinder F. Because of this difference in deflection, the amplitude that occurs during rotation of the drive shaft increases, causing the upper side of the drive shaft C to strongly strike against the upper end of the bearing portion H1 in the front head H, or to cause this deflection. Further, the centrifugal force acting on the rotor B2 of the motor B is further applied, and the upper end of the rotor B2 comes into contact with the stator B1 to cause large vibration.

FIGS. 7 (c) and 7 (d) schematically show individual states when the upper side of the drive shaft C bends during gas compression in the first and second cylinders E and F, respectively. , N1 indicate the root portion of the front head side bearing portion H1 bearing the drive shaft C, and N2 indicates the root portion of the rear head side bearing portion J1. Further, O3 indicates the maximum load applied in the orthogonal direction to the drive shaft C via the rollers E2, F2 and the eccentric portions C1, C2 during gas compression in the cylinders E, F. At this time, since the gas compression capacities in the cylinders E and F are the same, the maximum loads O3 on the drive shaft C in the cylinders E and F are the same. Further, P indicates the length of the front head side bearing portion H1.

When the maximum load O3 is applied to the drive shaft C during gas compression on the side of the first cylinder E, the drive shaft C bends and the front is bent as shown in FIG. It hits the root portion N1 of the head-side bearing portion H1, and connects the point of action of the maximum load O3 and the root portion N1 above the root portion N1 with respect to the axis C3 in the linear state of the drive shaft C. Deflection of deflection angle Θ3 occurs,
Further, at the time of gas compression on the side of the second cylinder F, as shown in FIG.
Of the drive shaft C with respect to the axis C3 of the drive shaft C, the deflection angle θ4 connecting the point of application of the maximum load O3 on the second cylinder F side and the root portion N1 occurs. At the eccentric portions C1 and C2 forming portions of the drive shaft C, the same load O3 is applied although the eccentric portions C1 and C2 have different eccentric directions, and the first cylinder E is the second cylinder.
Since it is located on the upper side with respect to the cylinder F, each load O3
The distance from the point where is acting to the root portion N1 is different,
The deflection angle Θ3 of the drive shaft C when the maximum load O3 is generated on the first cylinder E side is relative to the deflection angle Θ4 of the drive shaft C when the maximum load O3 is generated on the second cylinder F side. Greatly large. More specifically, the bending amount Z3 of the drive shaft at the upper end position of the front head side bearing portion H1 when the maximum load O3 is generated on the side of the first cylinder E is such that the length of the bearing portion H1 is P. So Z3 =
P × tan θ3, and when the maximum load O3 is generated on the second cylinder F side, the drive shaft deflection amount Z4 at the upper end position of the bearing portion H1 is Z4 = P × tan θ4.
Therefore, the bending amount Z3 of the drive shaft generated in the first cylinder is
However, the bending amount Z4 of the drive shaft generated in the second cylinder F is significantly large.

As described above, the bending angle Θ3 of the drive shaft C generated in the first cylinder E and the second cylinder F
A large difference occurs between the deflection angle Θ4 of the drive shaft C and the deflection amount Z3 of the drive shaft generated in the first cylinder E and the second cylinder F based on the difference in these deflection angles. Since a large difference is generated between the drive shaft and the amount of bending Z4 of the drive shaft, a large amplitude is generated due to the difference in the amount of bending of the drive shaft C during rotation, and the upper side of the drive shaft C is a bearing in the front head H. The upper end of the portion H1 is strongly biased to one side to cause a large vibration, and the deflection angle Θ3 of the drive shaft C due to the load generation on the first cylinder E side becomes large, so that the drive shaft C is large. The bending increases the centrifugal force when the rotor B2 of the motor B rotates, which causes a contact accident of the upper end of the rotor B2 with the stator B1.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the vibration of a multi-cylinder rotary compression by reducing the uneven contact of the drive shaft with the bearing portion of the front head and the contact of the rotor of the motor with the stator side. To provide a machine.

[0008]

In order to achieve the above object, the invention according to claim 1 is characterized in that a plurality of cylinders 5 and 6 containing rollers 52 and 62 are laminated via a middle plate 7 to form a front head 8 and The rear head 9 sandwiches the compression element 4 and the motor 2 is arranged on the front head 8 side. The motor 2 is formed in the axial direction of the drive shaft 3 connected to the motor 2 and has different eccentric directions. In a multi-cylinder rotary compressor in which the eccentric portions 31 and 32 are inserted into the rollers 52 and 62, the pressure receiving area by the compressed gas of the roller 52 installed in the cylinder chamber 51 on the front head 8 side is set to the rear head 9 Side cylinder chamber 6
That is, the pressure receiving area by the compressed gas of the roller 62 installed in 1 is made smaller.

According to the second aspect of the invention, the axial height of the cylinder chamber 51 and the roller 52 on the front head 8 side is made smaller than the axial height of the cylinder chamber 61 and the roller 62 on the rear head 9 side. Of.

Further, in the third aspect of the invention, the outer diameter of the roller 52 in the cylinder chamber 51 on the front head 8 side is made smaller than the outer diameter of the roller 62 in the cylinder chamber 61 on the rear head 9 side.

[0011]

According to the first aspect of the invention, the cylinder chambers 51 and 61 of the plurality of cylinders 5 and 6 are driven by the driving of the drive shaft 3.
When the fluid gas is compressed by eccentrically rotating each of the rollers 52 and 62, the rollers 52 and 6 are compressed by the compressed gas.
Even if a load is applied to the drive shaft 3 via the two and the eccentric parts 31 and 32, the front head side cylinder chamber 51
Since the pressure-receiving area of the roller 52 installed in the cylinder is smaller than the pressure-receiving area of the roller 62 installed in the rear head side cylinder chamber 61, the pressure is applied to the drive shaft 3 in the front head side cylinder chamber 51. The difference between the bending angle of the drive shaft 3 and the load applied to the drive shaft 3 in the rear head side cylinder chamber 61 can be reduced, as will be described later.

That is, the front head side cylinder chamber 5
Since the load applied to the drive shaft 3 is small at 1, the deflection angle around the position corresponding to the root portion of the front head 8 of the drive shaft 3 when the load is received by the front head side cylinder 5 is set. Since the difference between the bending angle of the drive shaft 3 when a load is applied to the rear head side cylinder 6 can be reduced, the difference in the bending amount is reduced, so that the amplitude of the rotation of the drive shaft 3 can be reduced. Therefore, it is possible to reduce the size of the drive shaft 3 that strongly strikes the outer end of the bearing portion of the front head 8 on one side and the upper end portion of the rotor of the motor 2 that contacts the stator. Can be reduced.

According to the second aspect of the invention, the axial height of the cylinder chamber 51 and the roller 52 on the front head 8 side is smaller than the axial height of the cylinder chamber 61 and the roller 62 on the rear head 9 side. Therefore, the front head side has a simple structure in which the heights of the cylinders 5 and 6 on the front and rear heads 8 and 9 and the rollers 52 and 62 mounted in the cylinders 5 and 6 are changed. The pressure receiving area of the roller 52 installed in the cylinder chamber 51 due to the compressed gas can be made smaller than the pressure receiving area of the roller 62 installed in the rear head side cylinder chamber 61 due to the compressed gas, and the amount of bending of the drive shaft 3 can be reduced. It is possible to reduce the difference between the two and reduce the vibration due to one-sided contact.

Further, in the invention according to claim 3, the roller 52 in the cylinder chamber 51 on the front head 8 side.
Since the outer diameter of each of the cylinders 5 and 6 is smaller than the outer diameter of the roller 62 in the cylinder chamber 61 on the rear head 9 side, the shape of the cylinders 5 and 6 on the front and rear heads 8 and 9 side is not changed. While using 6 as a common component, the front head side cylinder chamber 51 can be provided with a very simple structure in which the eccentric amounts of the rollers 52, 62 and the eccentric portions 31, 32 of the drive shaft 3 are changed. The pressure receiving area of the roller 52 to be compressed due to the compressed gas can be made smaller than the pressure receiving area of the roller 62 to be installed inside the rear head side cylinder chamber 61 due to the compressed gas, and the difference in the bending amount of the drive shaft 3 can be reduced. Then, vibration due to one-sided contact can be reduced.

[0015]

FIG. 5 shows a two-cylinder type rotary compressor. This compressor has a motor 2 having a stator 21 and a rotor 22 on an upper inner side of a hermetic casing 1.
And a compression element 4 driven by a drive shaft 3 coupled to the rotor 22 is provided on the lower side thereof. The compression element 4 includes upper and lower two first and second cylinders 5 and 6. A middle plate 7 that defines cylinder chambers 51 and 61 formed in the cylinders 5 and 6 is provided between the cylinders 5 and 6, and front and rear heads are provided above and below the cylinders 5 and 6, respectively. 8 and 9 are placed opposite to each other. Then, bearing portions 81 and 91 extending in the vertical direction are integrally formed at the central portions of the heads 8 and 9, respectively.
While supporting the drive shaft 3 with a bearing, the first and second eccentric parts having large diameters in which the eccentric directions are opposite to each other at two upper and lower positions between the bearing parts 81 and 91 of the drive shaft 3. 31 and 32 are respectively formed, and these eccentric portions 3 are formed.
1, 32 are inserted into first and second rollers 52, 62 which are rotatably arranged in the respective cylinder chambers 51, 61.

The first and second cylinders 5 and 6 are urged so as to always contact the outer peripheral surfaces of the rollers 52 and 62 via the spring 10, and the first and second blades 53 and 53 are urged. 63 is provided, so that the eccentric rotation of the rollers 52 and 62 in the cylinder chambers 51 and 61 respectively compresses the suction gas sucked into the cylinder chambers 51 and 61 with a phase difference of 180 degrees. I have to.

In the above-described two-cylinder rotary compressor, however, in the first embodiment shown in FIGS. 1 and 5, the first cylinder mounted inside the cylinder chamber 51 on the front head 8 side is the first cylinder.
The pressure receiving area of the roller 52 due to the compressed gas is housed in the cylinder chamber 61 on the rear head 9 side by the second roller 62.
It is smaller than the pressure receiving area by the compressed gas.

Specifically, as shown in FIGS. 1 and 5, the inner diameters of the cylinder chambers 51 and 61 provided in the first and second cylinders 5 and 6 are formed to be the same, and The overall axial height Q1 of one cylinder 5 is made lower than the overall axial height Q2 of the second cylinder 6, that is,
The height Q1 of the cylinder chamber 51, the roller 52, and the blade 53 of the first cylinder 5 is made lower than the height Q2 of the cylinder chamber 61, the roller 62, and the blade 63 of the second cylinder 6, so that the first cylinder By making the compression capacity of the fluid gas in 5 smaller than the gas compression capacity of the second cylinder 6 side, the gas pressure receiving area that the first roller 52 receives with the compressed gas at the time of gas compression in the first cylinder 5 Is smaller than the gas pressure receiving area that the second roller 62 receives when the gas is compressed in the second cylinder 6.

Further, as described above, the first cylinder 5
The overall axial height Q1 of the second cylinder 6 is lower than the overall axial height Q2 of the second cylinder 6,
When the gas pressure receiving area of the second roller 62 is made smaller than the gas pressure receiving area of the second roller 62, the compressed gas capacities of the first and second cylinders 5 and 6 in which the rollers 52 and 62 are arranged are large and small respectively. It is said that each of these cylinders 5, 6
The total gas compression capacity in is set so as to be the same as the total capacity of a stack of cylinders having the same capacity as in the conventional case.

With the above construction, the first and second cylinders 5 and 6 and the first and second rollers 52 and 62 mounted in the respective cylinders 5 and 6 can be changed in height with a simple construction. First roller 5 installed in the first cylinder 5
The pressure receiving area by the compressed gas of No. 2 can be made smaller than the pressure receiving area by the compressed gas of the second roller 62 installed in the second cylinder 6, that is, the first and second cylinders 5, 6 When gas compression is performed in each cylinder chamber 51, 61, the first,
A load in the orthogonal direction is applied to the drive shaft 3 through the second rollers 52 and 62 and the eccentric portions 31 and 32, and the load causes bending on the upper side of the drive shaft 3 to which the motor 2 is coupled. However, the overall axial height Q1 of the first cylinder 5 can be calculated as the overall axial height Q1 of the second cylinder 6.
Since it is formed lower than the first roller 52,
Can be made smaller than the gas pressure receiving area of the second roller 62, and as a result, the bending angle of the drive shaft 3 due to the load applied to the drive shaft 3 by the compressed gas in the first cylinder chamber 51 can be reduced. The difference between the compressed angle of the second cylinder chamber 61 and the bending angle of the drive shaft 3 due to the load applied to the drive shaft 3 can be reduced. Since the amplitude of the rotation of the drive shaft 3 can be reduced and the partial contact of the drive shaft 3 with the upper end of the bearing portion of the front head 8 can be reduced, the vibration can be reduced.

In order to make the gas pressure receiving area of the first roller 52 smaller than the gas pressure receiving area of the second roller 62, in the first embodiment described above, the rollers 52 and 62 and the cylinders 5 and 6 are arranged. The height of the first and second parts is changed as in the second embodiment shown in FIG.
The cylinders 5 and 6 have the same overall height in the axial direction, and
The cylinder chambers 51, 61 provided in the cylinders 5, 6 have the same inner diameter so that the total compression capacity of the fluid gas by the cylinders 5, 6 as a whole of the compressor becomes a predetermined capacity. Changing the outer diameters of the first and second rollers 52, 62 disposed in the cylinders 5, 6 so that the outer diameter of the first roller 52 is smaller than the outer diameter of the second roller 62. Thus, the gas pressure receiving area of the first roller 52 with respect to the second roller 62 may be reduced.

That is, as shown in (a) and (b) of FIGS. 2 and 3, the outer diameter of the first roller 52 provided on the first cylinder 5 side is R1, and the second cylinder 6 side is The outer diameter R1 of the first roller 52 is formed to be smaller than the outer diameter R2 of the second roller 62 when the outer diameter of the second roller 62 provided in the second roller 62 is R2. Then, the first compression chamber X of the first cylinder 5 defined by the blade 53
When the fluid gas is compressed by 1, the outer peripheral area of the first roller 52 facing the compression chamber X1 is made small, and the second cylinder 6 defined by the blade 63
When the fluid gas is compressed in the compression chamber X2, the compression chamber X2
The outer peripheral area of the second roller 62 facing the first roller 52 is made larger than that of the first roller 52.
By making the outer peripheral areas of the compression chambers 2 and 62 facing the compression chambers X1 and X2 different from each other, the first roller 5
The gas pressure receiving area of the second roller 62 received by the compressed gas in the first compression chamber X1 is made smaller than the gas pressure receiving area of the second roller 62 received by the compressed gas in the second compression chamber X2.

In the above-mentioned structure, the first and second cylinders 5 and 6 are not changed and the respective cylinders 5 and 6 are used as common parts while the rollers 52 and 62 and the drive shaft 3 are used. With a very simple configuration in which the eccentric amounts of the eccentric portions 31 and 32 are changed, the pressure receiving area of the first la 52 installed in the first cylinder 5 due to the compressed gas is installed in the second cylinder 6. It is possible to reduce the pressure receiving area of the second roller 62 by the compressed gas.

In the second embodiment, since the heights of the cylinders 5 and 6 are the same and constant as in the conventional case, the deflection of the conventional drive shaft shown in FIG. 7 and the second embodiment are the same. Comparing the deflection of the drive shaft, in the second embodiment,
The first and second rollers 52 in the second cylinders 5 and 6,
The state in which the upper side of the drive shaft 3 bends during gas compression due to the eccentric rotation of 62, as shown schematically in (a) and (b) of FIG. 4, N1 supports the drive shaft 3 as a bearing. When the front head side bearing portion 81 is the root portion, N2 is the rear head side bearing portion 91 root portion, and P is the length of the front head side bearing portion 81, the front head side cylinder chamber 51 is the motor 2 And the rear head side cylinder chamber 61 is arranged at a position separated from the motor 2, and the gas pressure receiving area of the first roller 52 arranged in the first cylinder 5 is Since it is smaller than the gas pressure receiving area of the second roller 62 arranged in the second cylinder 5, the second compression chamber X
The maximum load O2 is applied to the drive shaft 3 due to the gas compression in No. 2, whereas the first roller whose compressed gas pressure is small in the pressure receiving area during the gas compression in the first compression chamber X1. The maximum load O1 applied to the drive shaft 3 by the roller 52 is smaller than the maximum load O2.

That is, according to the present invention, the maximum load O3 applied to the drive shaft 3 at the time of gas compression in the first compression chamber X1 shown in FIG. Four
The maximum load O1 applied to the drive shaft 3 at the time of gas compression in the first compression chamber X1 shown by (B) can be reduced,
Further, the bending angle Θ1 of the drive shaft 3 due to the load O1
Can be smaller than the conventional deflection angle Θ3. Further, with respect to the maximum load O3 applied to the drive shaft 3 at the time of gas compression in the second compression chamber X2 shown in FIG. 7D, the second compression chamber shown in FIG. Since the maximum load O2 applied to the drive shaft 3 at the time of gas compression at X2 can be made large, and the bending angle Θ2 of the drive shaft 3 due to this load O2 can be made larger than the conventional bending angle Θ4. is there. Therefore, the first and second compression chambers X1,
The difference between the deflection angles Θ1 and Θ2 of the drive shaft 3 generated when the gas is compressed at X2 is calculated as follows.
It is possible to reduce the difference between 3 and Θ4.

Therefore, the drive shaft 3 due to the load O1
The bending angle Θ1 with respect to the axial center line C3 in the straight line is smaller than the conventional one, and the bending of the drive shaft 3 due to the load O2 is larger than the conventional one.
The deflection angle Θ1 due to the load O1 on the cylinder 5 and the second
The difference from the deflection angle Θ2 due to the load O2 in the cylinder 6 can be made smaller than in the conventional case, and the drive shaft 3 generated during gas compression in the first and second cylinder chambers 51 and 61.
Since the difference between the deflection angles Θ1 and Θ2 can be reduced, the amplitude of the rotation of the drive shaft 3 due to the deflection can be reduced accordingly. That is, when the maximum load O1 is generated on the side of the first cylinder 5, the amount of flexure Z1 located at the upper end of the bearing 81 of the front head 8 of the drive shaft 3 is generated.
Is Z1 = P × tan θ1, and the deflection amount Z2 of the drive shaft 3 when the maximum load O2 is generated on the second cylinder 6 side is Z2 = P × tan θ2. Deflection amounts Z1, Z2 of the drive shaft 3 at X2
Is smaller, the uneven contact at the upper end of the bearing portion 81 can be reduced, and the contact of the rotor 22 with the stator 21 can be reduced, so that the vibration of the compressor can be further reduced. Of.

Although the two-cylinder type rotary compressor has been shown in the above embodiments, the present invention is not limited to the two-cylinder type rotary compressor, but can be applied to a rotary compressor having a plurality of other cylinders.

[0028]

As described above, according to the first aspect of the invention, the pressure receiving area of the roller 52 installed in the cylinder chamber 51 on the side of the front head 8 close to the motor 2 by the compressed gas is Since the pressure receiving area by the compressed gas of the roller 62 installed in the cylinder chamber 61 on the rear head 9 side is made smaller, when the gas is compressed in the front head side cylinder chamber 51, the drive shaft 3 is compressed by the compressed gas.
It is possible to reduce the difference between the deflection angle of the drive shaft 3 due to the load applied to the drive shaft 3 and the deflection angle of the drive shaft 3 due to the load applied to the drive shaft 3 during gas compression in the rear head side cylinder chamber 61. Therefore, it is possible to reduce the vibration of the drive shaft 3 against the bearing end portion of the front head 8 and the rotor of the motor 2 from contacting the stator.

According to the second aspect of the invention, the axial height of the cylinder chamber 51 and the roller 52 on the front head 8 side is set to be smaller than the axial height of the cylinder chamber 61 and the roller 62 on the rear head 9 side. Since it is also made smaller, the cylinders 5 and 6 on the front and rear heads 8 and 9 side,
Rollers 52 and 6 installed in these cylinders 5 and 6, respectively.
The pressure receiving area by the compressed gas of the roller 52 installed in the front head side cylinder chamber 51 can be set to the rear head side cylinder chamber 6 with a simple structure for changing the height of the roller 2.
It is possible to reduce the pressure receiving area by the compressed gas of the roller 62 installed in No. 1 and to reduce the difference in the bending amount of the drive shaft 3 to reduce the vibration due to one-sided contact.

According to the third aspect of the invention, the outer diameter of the roller 52 in the cylinder chamber 51 on the front head 8 side is smaller than the outer diameter of the roller 62 in the cylinder chamber 61 on the rear head 9 side. Therefore, it is possible to use the cylinders 5 and 6 as common parts without changing the shapes of the cylinders 5 and 6 on the side of the front and rear heads 8 and 9, while maintaining the eccentricity of the rollers 52 and 62 and the drive shaft 3. With the extremely simple structure of changing the eccentricity of the parts 31 and 32, the pressure receiving area of the roller 52 installed in the front head side cylinder chamber 51 due to the compressed gas is adjusted to the roller installed in the rear head side cylinder chamber 61. The pressure receiving area of the compressed gas of 62 can be made smaller, and the difference in the amount of bending of the drive shaft 3 can be made smaller to achieve one-sided contact or the like. Than is vibration can be reduced by.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a multi-cylinder rotary compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a second embodiment of the present invention.

FIG. 3 is a plan view showing first and second cylinder portions in the second embodiment.

FIG. 4 is a schematic diagram showing a bending state of a drive shaft in the second embodiment.

FIG. 5 is a vertical cross-sectional view showing the overall structure of a multi-cylinder rotary compressor.

FIG. 6 is a vertical sectional view showing a conventional example.

FIG. 7 is a schematic view showing a bending state of the drive shaft.

[Explanation of symbols]

 2 Motor 3 Drive shaft 31, 32 Eccentric part 4 Compression element 5, 6 Cylinder 51, 61 Cylinder chamber 52, 62 Roller 7 Middle plate 8 Front head 9 Rear head

Claims (3)

[Claims] 1. A compression element in which a plurality of cylinders (5) (6) containing rollers (52, 62) are laminated via a middle plate (7) and sandwiched by a front head (8) and a rear head (9). (4) is formed, a motor (2) is disposed on the front head (8) side, and is formed in the axial direction of a drive shaft (3) connected to the motor (2),
A plurality of eccentric parts (31) (3) having different eccentric directions
2) In the multi-cylinder rotary compressor in which the rollers (52) (62) are fitted, the front head (8)
The roller (52) installed in the side cylinder chamber (51)
Is smaller than the pressure receiving area by the compressed gas of the roller (62) installed in the cylinder chamber (61) on the rear head (9) side. . 2. The axial height of the cylinder chamber (51) and the roller (52) on the front head (8) side is calculated from the axial height of the cylinder chamber (61) and the roller (62) on the rear head (9) side. The multi-cylinder rotary compressor according to claim 1, which is made small. 3. The outer diameter of the roller (52) in the cylinder chamber (51) on the front head (8) side is set to the roller (62) in the cylinder chamber (61) on the rear head (9) side.
The multi-cylinder rotary compressor according to claim 1, wherein the outer diameter is smaller than the outer diameter.