JP3395539B2 - Rotary compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor, and more particularly to a rotary compressor having a structure for preventing vertical movement of a rotating shaft during operation.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view schematically showing the structure of a conventional rotary compressor. Referring to FIG. 8, a conventional rotary compressor 30 </ b> B has a motor 4 which is an electric element arranged in the upper part of the hermetic container 1, and a compression element 13.

The motor 4 has a stator 2 mounted in the closed container 1 and a rotor 3 arranged in the central space of the stator 2 at a predetermined distance. The stator 2 has a stator core 2a and coils 2b attached to the upper and lower ends of the stator core 2a, respectively. Further, the rotor 3 is arranged so as to have an air gap 16 between itself and the stator 2.

A crankshaft 5 is press-fitted into the rotor 3, and a compression element 13 is connected to the motor 4 by the crankshaft 5.

The compression element 13 includes a front head 6, a rear head 7, a cylinder 9, and a rolling piston 12.
And have. This front head 6 and rear head 7
Support the crankshaft 5, and are provided on both upper and lower surfaces of the cylinder 9 so as to close the cylinder chamber 10. The rolling piston 12 is arranged in the closed cylinder chamber 10 and has an eccentric portion 11 of the crankshaft 5.
Installed on.

Further, from the outside of the closed container 1, the cylinder chamber 10
A suction pipe 23 for guiding the refrigerant gas inside and a discharge pipe 15 for discharging the compressed refrigerant gas from the inside of the compression container 1 to the outside are provided. A discharge muffler 14 is provided at the upper end of the front head 6 to suppress noise when discharging the compressed refrigerant gas from the compression element 13.

The conventional rotary compressor 30B is constructed as described above, and the compression element 13 performs the compression operation of the refrigerant gas. This compression operation is performed by the rolling piston 12 that receives the driving force from the motor 4 through the crankshaft 5.
Is performed by performing an eccentric rotary motion. That is, the refrigerant gas sucked into the cylinder chamber 10 from the suction pipe 23 is compressed by the eccentric rotational movement of the rolling piston. Then, a series of compression operation steps in which the step of sucking the refrigerant gas and the step of compressing the refrigerant gas are sequentially performed are continuously performed.

The compressed refrigerant gas is periodically discharged from a discharge hole (not shown) provided in the cylinder 9 through the discharge muffler 4 into the closed container 1 in accordance with the eccentric rotational movement of the rolling piston 12. It Then, the refrigerant gas passes through the air gap 16 between the stator 2 and the rotor 3 and the like, and is finally discharged from the discharge pipe 15 to the outside of the closed container 1.

[0009]

However, the conventional rotary compressor described above has a problem in that an abnormal sound (a gar noise) is generated by the vertical vibration of the crankshaft 5. Hereinafter, this will be described in detail.

As described above, the refrigerant gas is compressed once per one rotation of the rolling piston 12 and is periodically discharged to the outside of the cylinder chamber 10, so that the discharged refrigerant gas is pulsated. Become. The pulsation of the refrigerant gas is moderated to some extent because the refrigerant gas is once discharged into the muffler 14.

However, when the rolling piston 12 is rotated at a high speed, the muffler 14 alone cannot suppress the pulsation of the discharged refrigerant gas. Therefore, the refrigerant gas is periodically discharged from the holes of the muffler 14 to the space (primary space) S1 between the motor 4 and the compression element 13, and the pressure in the primary space S1 is increased. Is high when the refrigerant gas is discharged, and is low otherwise, causing pulsation. Therefore, the differential pressure generated between the relatively low pressure space (secondary space) S2 on the motor 4 and the relatively high pressure primary space S1 varies according to this pulsation.

On the other hand, in a rotary compressor, there is usually a vertical gap X between the upper surface of the eccentric portion 11 of the crankshaft 5 and the lower surface of the front head 6.

Therefore, the high pressure primary space S1 and the low pressure 2
When the differential pressure generated between the secondary space S2 and the next space S2 becomes extremely large,
The pressure in the primary space S1 lifts the rotor 3 and the crankshaft 5 upward. For this reason, as described above, when the differential pressure generated between the primary space S1 and the secondary space S2 fluctuates in accordance with the pulsation, the rotor 3 and the crankshaft 5 cause vertical vibration in accordance with the pulsation. Become. Due to this vertical vibration, the eccentric portion 11 of the crankshaft 5 intermittently collides with the front head 6 or the rear head 7 and an abnormal sound is generated.

As a technique for preventing the generation of this abnormal sound,
There has been a method of shifting the upper end portion of the rotor 3 from the upper end surface of the stator core 2a by a dimension M ₁ (a so-called magnet center shift method). According to this method, the rotor 3 and the crankshaft 5 can be urged downward by displacing the rotor 3 upward with respect to the stator core 2a, and thus the rotor 3 and the crankshaft 5 can be urged downward. Vibration can be prevented.

However, in the method of displacing the magnet center, the displacement amount M ₁ of the rotor 3 must be made sufficiently large in order to eliminate the abnormal noise caused by the collision. However, there has been a problem that increasing the shift amount M ₁ significantly affects the characteristics of the motor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotary compressor capable of preventing the generation of abnormal noise accompanying the vertical vibration of the crankshaft without affecting the characteristics of the motor.

[0017]

According to a first aspect of the present invention, there is provided a rotary compressor having an electric element arranged in an upper part of a hermetic container and an electric element arranged in a lower part of the hermetic container and connected to the electric element by a rotary shaft. The compression element has a cylindrical cylinder, and the compression element is disposed in the cylinder and is rotated along the inner peripheral surface of the cylinder by being given a rotational force from the electric element through the rotation shaft to generate the refrigerant gas. A rotary compressor having a rotary piston for compression, which has the following features.

In this rotary compressor, the volume of the first space under the electric element surrounded by the electric element, the hermetic container, and the surface level of the cylinder on the electric element side is V1, and the volume is surrounded by the electric element and the hermetic container. The volume of the second space on the electrically driven element is V2, the length of the passage space connecting the first and second spaces is L, the cross-sectional area of the passage space is S, and the first and second spaces are When the resonance frequency generated during the period is F, the sound velocity in the refrigerant gas is C, the number of cylinders is N, and the number of rotations of the rotary piston per unit time is the motion frequency,

[0019]

[Equation 2]

It is characterized by satisfying the relationship of As a result of intensive studies, the inventors of the present application have confirmed that the main cause of the generation of abnormal sound is pulsation due to resonance generated between the primary space and the secondary space. As a result of further experiments based on this, the inventors of the present application have found the above relational expression that can suppress the generation of abnormal sound. That is, by designing the dimensions of each component of the rotary compressor or adjusting the operation so as to satisfy the above relational expression, it is possible to suppress the generation of abnormal noise without degrading the motor characteristics.

In the rotary compressor according to the second aspect of the present invention, the electric element is arranged in the central space of the stator with the stator having the stator core mounted in a hermetically sealed container and spaced from the inner peripheral surface of the stator. And a rotator which is operated. The upper end of this rotor projects upward from the upper end surface of the stator core.

By further shifting the magnet center in this way, the generation of abnormal sound can be suppressed more effectively.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view schematically showing the structure of a rotary compressor according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view taken along the line AA of FIG.

Referring to FIGS. 1 and 2, a motor 4 serving as an electric element is arranged in an upper part of the closed container 1, and a compression element 13 is arranged in a lower part thereof.

The motor 4 has a stator 2 and a rotor 3. The stator 2 has a cylindrical stator core 2a that is mounted on the inner wall of the closed container 1 and is made of a material that allows magnetic flux lines to easily pass therethrough, and coils 2b that are arranged at both upper and lower ends of the stator core 2a. The rotor 3 is made of a permanent magnet and is arranged in the central space of the stator 2 with an air gap 16 therebetween.

A crankshaft 5 is press-fitted into the rotor 3, and the motor 4 and the compression element 13 are connected via the crankshaft 5.

The compression element 13 is, for example, a two-cylinder type rotary compressor, has two first and second cylinders 9a and 9b, and other than that, the front head 6 is provided.
, A rear head 7, a middle plate 8, and first and second rolling pistons 12a and 12b.

The front head 6, the rear head 7, and the middle plate 8 support the crankshaft 5. A front head 6 and a middle plate 8 are provided on both upper and lower end surfaces so as to close the cylinder chamber 10a of the first cylinder 9a. Further, a middle plate 8 and a rear head 7 are provided on each of the upper and lower end surfaces so as to close the cylinder chamber 10b of the second cylinder 9b. First and second rolling pistons 12a and 12b are arranged in the first and second cylinder chambers 10a and 10b, respectively. The first and second rolling pistons 12a and 12b are the first and second rolling pistons of the crankshaft 5, respectively.
Is attached to each of the eccentric portions 11a and 11b. The first and second rolling pistons 12a and 12b
Are arranged on the crankshaft 5 such that their eccentric directions differ from each other by 180 °.

A discharge muffler 14 for suppressing noise when the compressed refrigerant gas is discharged into the closed container 1 is arranged on the upper end surface of the front head 6. Further, a plurality of through holes 17 are provided so as to penetrate from the upper end surface of the rotor 3 to the lower end surface. Further, notches 18a and 18b are provided on the outer peripheral end of the stator core 2a so as to penetrate from the upper end surface to the lower end surface of the stator core 2a.

A discharge pipe 15 for discharging the refrigerant gas compressed to a high pressure by the compression element 13 to the outside of the closed container 1 is provided.

Then, the rotary compressor 30A of the present embodiment
Is designed and configured to satisfy the following relational expression.

[0033]

[Equation 3]

The definition of each parameter in the above equations (1) and (2) will be described below. <1> Primary Space Volume [V1] The primary space volume [V1] is the volume of the space S1 surrounded by the motor 4 and the compression element 13 inside the closed container 1. That is, the primary space volume [V1] is below the motor 4,
It is the volume of the space surrounded by the motor 4, the closed container 1, and the upper surface level (one-dot chain line EE) of the first cylinder 9a.

<2> Secondary Space Volume [V2] The secondary space volume [V2] is the volume of the empty space S2 above the motor 4 inside the closed container 1, that is, above the motor 4 and above the motor 4. It is the volume of the space surrounded by the closed container 1.

<3> Primary-Secondary Space Passage Cross Section [S] The primary-secondary space passage cross-section [S] is the primary and secondary space defined by <1> and <2>. It is the sum of the cross-sectional areas of the main passages connecting S1 and S2. Specifically, the through hole 17 provided in the rotor 3 and the notch 18 in the stator core 2a
The a and 18b and the air gap 16 correspond to the main passage connecting the primary and secondary spaces S1 and S2. Further, for example, when the rotor 3 does not have the through hole 17, the stator core 2
The total value of the cross-sectional areas of the notches 18a and 18b of a and the air gap 16 corresponds to the primary-secondary space passage sectional area [S].

<4> Primary-Secondary Space Passage Length [L] The primary-secondary space passage length [L] is the primary and secondary space defined by <1> and <2>. It is the length of the passage connecting S1 and S2. Specifically, in FIG. 1, the stator core 2
The length L of a corresponds to the primary-secondary space passage length [L].

<5> Resonance frequency [F] The resonance frequency [F] is defined by <1> and <2>.
It is a resonance frequency generated by the resonance phenomenon between the secondary and secondary spaces S1 and S2.

<6> Sound Velocity [C] in Refrigerant Gas The sound velocity [C] in the refrigerant gas is a value theoretically obtained from the pressure and temperature inside the closed container 1, and is the rotary compression of the present embodiment. The machine has a range of about 170 to 185 (m / sec).

<7> Parameter N Parameter N indicates the type of cylinder, and N =
1 means 1 cylinder type, N = 2 means 2 cylinder type (FIG. 1).

<8> Operating frequency The operating frequency is the rolling piston 12 per unit time.
The rotation speeds of a and 12b.

As a result of intensive studies, the inventors of the present invention have derived the above equation (2). The process of deriving the equation (2) will be described below.

First, the inventors of the present application conducted an experiment, and as shown in FIG.
In the two-cylinder rotary compressor shown in Fig. 5, the vertical movement of the crankshaft 5 when the operating frequency is changed, and the primary and secondary
The differential pressure pulsation width between the next spaces S1 and S2 was examined under different specifications (specification 1 and specification 2).

The settings of specifications 1 and 2 are shown in the table below.

[0045]

[Table 1]

As is clear from the above table, in the specification 2, the primary space volume V1 is set smaller than that in the specification 1. The results of the above experiments for these specifications 1 and 2 are shown in FIGS.

First, according to the formula (1), the resonance frequencies / 2 in specifications 1 and 2 are 88 to 96 Hz and 101 to 110H, respectively.
z. Based on this fact, it can be seen from FIGS. 3 and 4 that both the specifications 1 and 2 have the maximum crank vertical movement and the differential pressure pulsation width at the resonance frequency / 2.

It was also found that the resonance frequency becomes higher by decreasing the primary space S1, and the gutter sound frequency becomes higher accordingly. That is, it was found that the resonance frequency and the gutter sound generation frequency have a proportional relationship.

From this experimental result, it became clear that the vertical vibration of the crankshaft occurs due to the resonance phenomenon of the primary and secondary spaces S1 and S2. It was also confirmed that the resonance frequency inside the closed container 1 was obtained by the formula (1).

Note that, in FIG. 3, when the vertical movement of the crank becomes large, the guarantor sounds as an abnormal sound. See also FIG.
The vertical movement of the crank on the vertical axis is the ratio of the distance actually moved by the crankshaft to the maximum value of the mechanical clearance in which the crankshaft can move in the vertical direction, expressed as a percentage. It should be noted that the scale 0.1 at the lower left of the drawing in FIG.
Indicates a scale of 0.1 of the differential pressure pulsation width.

The inventors of the present application conducted further experiments to investigate the relationship between the operating frequency at which a gutter sound is generated and the theoretical resonance frequency under various specifications in a rotary compressor.

These relationships were examined for each of the two-cylinder rotary compressor and the one-cylinder rotary compressor shown in FIG. The results are shown in FIG. 5 for the 2-cylinder type and in FIG. 6 for the 1-cylinder type.

In FIG. 5, the vertical axis represents the actual resonance frequency (resonance frequency / 2) in the 2-cylinder type.

First, with reference to FIG. 5, the x mark indicates the gutter sound generation start frequency. Here, the gar-sound generation start frequency is, when fixed to the theoretical resonance frequency at the position of ×,
Gar noise generation at the position marked with x indicates that a gar noise is generated at an operating frequency or higher. That is, theoretical resonance frequency /
2 is about 90, and the garbled sound generation operating frequency is about 84.
For example, fixing the theoretical resonance frequency / 2 to 90,
When the garment-sound generating operation frequency is changed, a squealing sound is generated when the gar-sound generating operation frequency is 84 or more.

From the results shown in FIG. 5, the inventors of the present application have found that if the operating frequency is (theoretical resonance frequency / 2) /1.2 or less, any specifications can be satisfied as long as the formula (1) is satisfied. It was found that no sound was generated.

The same is true for the one-cylinder type in FIG. 6, and if the operating frequency is less than or equal to the theoretical resonance frequency / 1.2, a gutter sound is generated regardless of any specifications as long as Expression (1) is satisfied. The present inventors have found that this is not the case.

As a result, the inventors of the present application were able to derive the equation (2) indicating that the operating frequency is (theoretical resonance frequency F / number of cylinders N) /1.2 or less.

The sound velocity C in the refrigerant gas is theoretically determined by the temperature and the pressure of the refrigerant gas as described above, and the temperature and the pressure of the refrigerant gas are designed / designed for the rotary compressor.
It is almost decided by the structure. For this reason, in the rotary compressor, the sound velocity C in the refrigerant gas is almost determined from these relationships, and is usually in the range of 170 to 185 m / sec.

Therefore, the inventors of the present application investigated whether or not the above equation (2) could be satisfied under the condition that the sound velocity C in the refrigerant gas was 170 to 185 m / sec. The results are shown in the table below.

[0060]

[Table 2]

From this result, if at least the sound velocity C in the refrigerant gas is 170 to 183 m / sec, equation (2)
It was found that Therefore, it is considered that the formulas (1) and (2) can be applied to the rotary compressor having a sound velocity C in the refrigerant gas of 170 to 185 m / sec without any problem.

The settings of specifications 3 and 4 in the above table are as shown in the table below.

[0063]

[Table 3]

From the results of the various experiments described above, if the rotary compressor is constructed so as to satisfy the formulas (1) and (2), an abnormal noise (gar noise) due to the vertical vibration of the crankshaft 5 is generated. ) Has been found to be preventable. That is,
Formula (2) is satisfied by reducing the volumes V1 and V2 of the primary space S1 and the secondary space S2, shortening the primary-secondary space passage length L, and increasing the passage cross-sectional area S. It has been found that such a design can prevent the generation of abnormal sound due to the resonance phenomenon.

Further, for example, when it is not possible to suppress the generation of the gurgling sound only by the force due to the displacement of the magnet center, the formula (1) is used to prevent the gurgling sound without adding a special structure inside the compressor. And the configuration satisfying the expression (2) is effective.

That is, the rotor 3 and the rotor 3 are formed by satisfying the formulas (1) and (2) and shifting the upper end surface of the rotor 3 from the upper surface of the stator core 2a upward by a dimension M as shown in FIG. Since the crankshaft 5 is urged downward in the drawing, it is possible to more effectively prevent the generation of abnormal noise.

The amount M of displacement of the rotor 3 from the stator core 2a is, for example, 5 mm.

For the compression element 13, it is desirable to use a so-called swing type rotary compressor.

FIG. 7 is a schematic sectional view taken along the line BB of FIG. 1 when a so-called swing type rotary compressor is used as the compressor. Referring to FIG. 7, in a so-called swing type rotary compressor, a blade 21 is fitted and integrated with the outer circumference of a rolling piston 12a arranged in a cylinder 9a. The blade 21 is supported by an oscillating body 22 rotatably arranged in the cylinder 9a so as to be able to move back and forth.

With such a structure, in the so-called swing type compressor, the rolling piston 12a revolves without receiving the rotational force of the crankshaft 5 and rotating. By the revolution of the rolling piston 12a, the refrigerant gas is sucked into the suction chamber H in the cylinder chamber 10a through the suction port 23 and then compressed, and after the compression is completed, the valve plate 25 is opened to discharge from the compression chamber I. The compressed refrigerant gas is discharged to 24.

As described above, in the so-called swing type, the rolling piston 12a and the blade 21 are integrated. Therefore, there are the following advantages as compared with the rotary compressor of the type (hereinafter referred to as the conventional type) in which the blade and the rolling piston are separated and the blade is in constant contact with the outer peripheral surface of the rolling piston by pressing.

First, in a so-called swing type compressor,
When the rolling piston 12a revolves, it is not necessary to press the blade 21 against the outer peripheral surface of the rolling piston 12a to bring it into contact with the rolling piston 12a.
It is possible to eliminate friction loss and power loss in the contact portion between the blade 2a and the blade 21.

Further, in a so-called swing type compressor, since the blade 21 is fixed to the rolling piston 12a, the compression chamber I to the suction chamber H are contacted with each other at the contact portion between the blade and the rolling piston as in the conventional compressor. Gas leakage is prevented, and volume efficiency can be improved.

However, the configuration of the present embodiment is more preferable if it is used in a so-called swing type compressor, and it is sufficient even if it is used in a conventional rotary type compressor in which the blade and the rolling piston are separated. It is possible to prevent abnormal noise from being generated.

In the present embodiment, the two-cylinder rotary compressor shown in FIG. 1 has been described, but the one-cylinder rotary compressor shown in FIG. 8 has the formulas (1) and (2).
A configuration that satisfies the above may be applied. In this case, 1
The next space volume [V1] is the volume of the space below the motor 4 and surrounded by the motor 4, the closed container 1 and the upper surface level of the cylinder 9.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0077]

As described above, according to the rotary compressor of the first aspect, the inventors of the present application have found a relational expression capable of suppressing the generation of abnormal noise in the rotary compressor. Therefore, by designing each component of the rotary compressor so as to satisfy this relational expression and adjusting the operation, it is possible to prevent the occurrence of abnormal noise without degrading the motor characteristics.

According to the rotary compressor of the second aspect, the rotary compressor satisfies the above relational expression and the magnet center is further displaced.
It is also possible to prevent the generation of abnormal sound more effectively.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the configuration of a rotary compressor according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along the line AA of FIG.

FIG. 3 is a graph showing the relationship between operating frequency and vertical crank movement in a rotary compressor.

FIG. 4 is a graph showing a relationship between an operating frequency and a differential pressure pulsation width in a rotary compressor.

FIG. 5 is a graph showing a relationship between a guarantor generation operating frequency and a theoretical resonance frequency in a two-cylinder rotary compressor.

FIG. 6 is a graph showing a relationship between a garbled sound generating operating frequency and a theoretical resonance frequency in a one-cylinder rotary compressor.

7 is a schematic cross-sectional view taken along the line BB of FIG. 1 when using a so-called swing type compressor.

FIG. 8 is a sectional view schematically showing a configuration of a conventional rotary compressor.

[Explanation of symbols]

1 closed container 2 stator 3 rotor 4 motor 5 crankshaft 9a, 9b cylinder 10a, 10b Cylinder chamber 12a, 12b rolling piston 13 compression element 16 air gap 17 Through hole 18a, 18b Notch

Continuation of the front page (56) Reference JP-A-7-167054 (JP, A) JP-A-2-157492 (JP, A) JP-A-60-125790 (JP, A) JP-A-2-164298 (JP , A) JP 63-268990 (JP, A) JP 6-159281 (JP, A) JP 7-247974 (JP, A) Actually developed 63-82085 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04B 39/00 101 F04C 29/06

Claims (2)

(57) [Claims] 1. An electric element (4) arranged in an upper part in a closed container (1) and a lower part in the closed container (1) and connected to the electric element (4) by a rotating shaft (5). A compression element (13) connected to said compression element (1
3) is a cylindrical cylinder (9a, 9b), and is arranged in the cylinder (9a, 9b) and the electric element (4)
A rotary piston (12a, 12b) that compresses the refrigerant gas by rotating along the inner peripheral surface of the cylinder (9a, 9b) by being given a rotational force from the rotary shaft (5).
A rotary compressor having: the electric element (4) surrounded by the electric element (4), the closed container (1), and the surface level of the cylinder (9a) on the electric element (4) side. ) The volume of the lower first space (S1) is V1, and the electric element (4) and the closed container (1)
A second space (S) on the electric element (4) surrounded by
The volume of 2) is V2, and the first and second spaces (S
1, S2) connecting passage spaces (16, 17, 18a, 18)
The length of b) is L and the passage space (16, 17, 18)
a, 18b) is S, the resonance frequency generated between the first and second spaces (S1, S2) is F, the sound velocity in the refrigerant gas is C, and the cylinder (9a , 9b) and the operating frequency is the number of rotations of the rotary pistons (12a, 12b) per unit time, A rotary compressor characterized by satisfying the relationship of. 2. The electric element (4) comprises a stator (2) having a stator core (2a) mounted in the closed container (1), and the stator (2) fixed in a central space of the stator (2). A rotor (3) arranged at a distance from the inner peripheral surface of the child (2), and an upper end of the rotor (3) projects upward from an upper end surface of the stator core (2a), The rotary compressor according to claim 1.