JPH1089252A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal sound to be generated with the vertical vibration of a crank shaft without affecting characteristics of a motor, by satisfying the relationship expressed by formula among resonance frequency to be generated between a first space below an electric element and a second space above the electric space, acoustic velocity in gaseous refrigerant, the number of cylinders, etc. SOLUTION: A motor 4 as an electric element is arranged on the upper part in a closed container 1 of a rotary compressor 30A, and a compression element 13 is arranged on the lower part. The motor 4 is provided with a stator 2 and a rotator 3, a crank shaft 5 is pressed into the rotator 3, and the motor 4 is connected to the compression element 13 through the crank shaft 5. The rotary compressor 30A is so designed and constituted as to satisfy the relationship indicated by an expression. In the expression, V1 indicates the capacity m<3> of a primary space S1, V2 indicates the capacity m<3> of a secondary space S2, L indicates the length m of a passage between primary and secondary spaces, S indicates the total sectional area m<2> of the passage between the primary and secondary spaces, F indicates resonance frequency Hz, C indicates the acoustic velocity m/sec (170 to 185m/sec), and N indicates the number of cylinders.

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 a rotary shaft from moving up and down 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, and a compression element 13, which are arranged at an upper part in the closed casing 1.

[0003] The motor 4 has a stator 2 mounted in an airtight container 1 and a rotor 3 arranged at a predetermined distance in a central space of the stator 2. The stator 2 has a stator core 2a and coils 2b attached to upper and lower ends of the stator core 2a. Further, the rotor 3 is arranged so as to have an air gap 16 between the rotor 3 and the stator 2.

[0004] 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, a rolling piston 12
And This front head 6 and rear head 7
Are supported on the upper and lower surfaces of the cylinder 9 so as to close the cylinder chamber 10. The rolling piston 12 is disposed in the closed cylinder chamber 10 and has an eccentric portion 11 of the crankshaft 5.
Mounted on

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

[0007] The conventional rotary compressor 30B is configured as described above, and the compression element 13 compresses the refrigerant gas. This compression operation is performed by the rolling piston 12 receiving the driving force of the motor 4 through the crankshaft 5.
Is performed by eccentric rotational movement. That is, the refrigerant gas sucked into the cylinder chamber 10 from the suction pipe 23 is compressed by the eccentric rotation of the rolling piston. Then, a series of steps of the compression operation, which sequentially shifts from the step of sucking the refrigerant gas to the step of compressing, is performed continuously.

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. You. Then, the refrigerant gas passes through an 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, in the conventional rotary compressor described above, there is a problem that an abnormal sound (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 rotation of the rolling piston 12 and is periodically discharged to the outside of the cylinder chamber 10 each time. Become. The pulsation of the refrigerant gas is reduced 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 hole of the muffler 14 into the space (primary space) S1 between the motor 4 and the compression element 13, and the pressure in the primary space S1 is reduced. Is high at the time of discharge of the refrigerant gas, and becomes low at other times to cause 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 fluctuates in accordance with the pulsation.

On the other hand, in the rotary compressor, a vertical gap X generally exists 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
If the pressure difference between the next space S2 and the next space S2 becomes significantly large,
The rotor 3 and the crankshaft 5 are lifted upward by the pressure in the primary space S1. Therefore, 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,
How shifting the upper portion of the rotor 3 in the upper end surface of the stator core 2a by a distance M ₁ (method of shifting the so-called magnet center) had. According to this method, the rotor 3 and the crankshaft 5 can be urged downward by moving the rotor 3 upward with respect to the stator core 2a to obtain the action of the magnet pull hose. Vibration can be prevented.

However, in the method of shifting the magnet center, it is necessary to sufficiently increase the shift amount M ₁ of the rotor 3 in order to eliminate abnormal noise due to collision. However, increasing the shift amount M _1, there is a problem that would significantly affect the properties of the motor.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a rotary compressor capable of preventing occurrence of abnormal noise due to vertical vibration of a crankshaft without affecting characteristics of a motor.

[0017]

According to a first aspect of the present invention, there is provided a rotary compressor, wherein an electric element disposed at an upper part in a closed container and a motor element disposed at a lower part in the closed container and connected to the electric element by a rotating shaft. The compression element has a cylindrical cylinder, and the compression element rotates along the inner peripheral surface of the cylinder by being provided in the cylinder and being provided with a rotational force from the electric element through a rotating shaft, thereby causing the refrigerant gas to flow. A rotary compressor having a rotating piston for compression, which has the following features.

In this rotary compressor, the volume of a first space under the electric element surrounded by the electric element, the closed casing and the surface of the cylinder on the electric element side is set to V1, and the volume is surrounded by the electric element and the closed vessel. V2 represents the volume of the second space above the electrically driven element, L represents the length of the passage space connecting the first and second spaces, S represents the cross-sectional area of the passage space, and the first and second spaces. When the resonance frequency generated during F is represented by F, the sound velocity in the refrigerant gas is represented by C, the number of cylinders is represented by N, and the number of rotations of the rotating piston per unit time is represented by the motion frequency,

[0019]

(Equation 2)

It is characterized by satisfying the following relationship. As a result of intensive studies, the present inventors have confirmed that the main cause of the generation of abnormal noise is pulsation due to resonance generated between the primary space and the secondary space. As a result of further experiments and the like based on this, the inventors of the present application have found the above-mentioned relational expression that can suppress occurrence 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 occurrence of abnormal noise without deteriorating the motor characteristics.

In the rotary compressor according to the second aspect, the electric element is disposed in the central space of the stator at a distance from the inner peripheral surface of the stator. Rotator. The upper end of the rotor protrudes upward from the upper end surface of the stator core.

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

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

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

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

The motor 4 has a stator 2 and a rotor 3. The stator 2 has a cylindrical stator core 2a, which is mounted on the inner wall of the closed casing 1 and is made of a material through which magnetic flux lines can easily pass, and coils 2b disposed at both upper and lower ends of the stator core 2a. The rotor 3 is made of a permanent magnet, and is disposed in a 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 and has two first and second cylinders 9a and 9b.
, 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 each of the upper and lower end surfaces so as to close the cylinder chamber 10a of the first cylinder 9a. Also, a middle plate 8 and a rear head 7 are disposed 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, 12b are disposed in the first and second cylinder chambers 10a, 10b, respectively. The first and second rolling pistons 12a and 12b are connected to the first and second rolling pistons 12 of the crankshaft 5.
Is mounted on each of the eccentric portions 11a and 11b. The first and second rolling pistons 12a, 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 discharging the compressed refrigerant gas into the closed casing 1 is disposed on the upper end surface of the front head 6. Also, 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. Notches 18a and 18b are provided at 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 vessel 1 is provided.

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 casing 1. That is, the primary space volume [V1] is below the motor 4,
This is the volume of a space surrounded by the motor 4, the closed casing 1, and the upper surface level (dashed 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 casing 1, that is, above the motor 4, This is the volume of the space surrounded by the closed container 1.

<3> Primary-secondary space passage sectional area [S] The primary-secondary space passage sectional area [S] is a 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
a, 18b and the air gap 16 correspond to the main passages connecting the primary and secondary spaces S1, S2. For example, when the rotor 3 has no through hole 17, the stator core 2
The total value of the cross-sectional areas of the notches 18a and 18b and the air gap 16 corresponds to the primary-secondary space passage cross-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 path connecting S1 and S2. Specifically, in FIG.
The length L of a corresponds to the primary-secondary space passage length [L].

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

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

<7> Parameter N Parameter N indicates the type of cylinder.
1 indicates a one-cylinder type, and N = 2 indicates a two-cylinder type (FIG. 1).

<8> Operating Frequency The operating frequency is determined by the rolling piston 12 per unit time.
a, 12b are the rotation speeds.

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

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

The specifications 1 and 2 are set as shown in the following table.

[0045]

[Table 1]

As is clear from the above table, the specification 2 has a smaller primary space volume V1 than the specification 1. The results of the above experiments in these specifications 1 and 2 are shown in FIG. 3 and FIG.

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

It was also found that the resonance frequency was increased by reducing the primary space S1, and the garner generation frequency was increased accordingly. That is, it was found that there was a proportional relationship between the resonance frequency and the garner sound generation frequency.

From the experimental results, it has been clarified that the vertical vibration of the crankshaft is generated by the resonance phenomenon of the primary and secondary spaces S1 and S2. Further, it was also confirmed that the resonance frequency inside the closed container 1 was determined by the equation (1).

In FIG. 3, when the vertical movement of the crank increases, the gar noise is heard as an abnormal sound. FIG.
The vertical movement of the crank on the vertical axis indicates 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 as a percentage. The scale 0.1 at the lower left of FIG.
Indicates a scale of 0.1 of the differential pressure pulsation width.

The inventors of the present application conducted further experiments and examined the relationship between the operating frequency at which gar noise is generated and the theoretical resonance frequency under various specifications in the 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 two-cylinder type and in FIG. 6 for the one-cylinder type.

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

First, referring to FIG. 5, a cross mark indicates a garner sound generation start frequency. Here, the gar sound generation start frequency is defined as the theoretical resonance frequency at the position of the mark x.
This indicates that a gurgling sound is generated when the operating frequency is equal to or higher than the gulling sound generation operation frequency at the position of the mark x. That is, the theoretical resonance frequency /
2 is about 90, and the gar tone generating operation frequency is about 84 x mark G
Taking the example as an example, fixing the theoretical resonance frequency / 2 to 90,
When the germ sound generation operation frequency is changed, a germ sound is generated when the germ sound generation operation frequency is 84 or more.

Based on the results shown in FIG. 5, the inventors of the present application have found that if the operating frequency is equal to or less than (theoretical resonance frequency / 2) /1.2, the specification of the germ frequency can be obtained regardless of the specifications as long as the expression (1) is satisfied. I found no sound.

The same applies to the one-cylinder type shown in FIG. 6. If the operating frequency is equal to or lower than the theoretical resonance frequency / 1.2, garble noise is generated regardless of the specification as long as the expression (1) is satisfied. The inventors of the present application have found that they do not.

Thus, the inventors of the present application were able to derive equation (2) indicating that the operating frequency was equal to or less than (theoretical resonance frequency F / number of cylinders N) /1.2.

The sound speed 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 determined by the design of the rotary compressor.
It is largely determined by the structure. For this reason, in the rotary compressor, the sound speed C in the refrigerant gas is substantially determined from these relationships, and is usually in the range of 170 to 185 m / sec.

Therefore, the present inventors examined whether or not the above equation (2) could be satisfied under the condition that the sound speed 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, the equation (2)
Has been found to be satisfied. Therefore, it is considered that Equations (1) and (2) can be applied to a rotary compressor having a sound velocity C in a refrigerant gas of 170 to 185 m / sec with almost no problem.

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

[0063]

[Table 3]

From the results of the various experiments described above, if the structure of the rotary compressor is designed to satisfy the equations (1) and (2), abnormal noise (gar noise) due to the vertical vibration of the crankshaft 5 will be described. ) Can be prevented. That is,
Equation (2) is satisfied by reducing the volumes V1, V2 of the primary space S1 and the secondary space S2, reducing the length L of the primary-secondary space passage, and increasing the cross-sectional area S of the passage. It has been found that such a design can prevent occurrence of abnormal noise due to the resonance phenomenon.

Also, for example, when the generation of garble noise cannot be suppressed only by the force of shifting the magnet center, the expression (1) is used to prevent the generation of garble noise without adding a special structure inside the compressor. A configuration satisfying the expression (2) is effective.

That is, by making the structure satisfying the equations (1) and (2) and displacing the upper end face of the rotor 3 upward from the upper face of the stator core 2a by the dimension M as shown in FIG. Since the crankshaft 5 is urged downward in the figure, it is possible to more effectively prevent the occurrence of abnormal noise.

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

It is desirable that a so-called swing type rotary compressor be used as the compression element 13.

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 to and integrated with an outer periphery of a rolling piston 12a arranged in a cylinder 9a. The blade 21 is supported by a rocking body 22 rotatably arranged on the cylinder 9a so as to be able to advance and retreat.

With such a configuration, in a so-called swing type compressor, the rolling piston 12a revolves without rotating by receiving the rotational force of the crankshaft 5. By the revolution of the rolling piston 12a, the refrigerant gas is sucked into the suction chamber H in the cylinder chamber 10a from the suction port 23, and then compressed. 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. For this reason, there are the following advantages as compared with a rotary compressor of the type in which the blade is separated from the rolling piston and the blade constantly contacts the outer peripheral surface of the rolling piston by pressing (hereinafter, referred to as a conventional type).

First, in a so-called swing type compressor,
Since there is no need to press the blade 21 into contact with the outer peripheral surface of the rolling piston 12a when the rolling piston 12a revolves, the rolling piston 1 with a small amount of lubrication is required.
Friction loss and power loss at the contact portion between the blade 2a and the blade 21 can be eliminated.

In a so-called swing type compressor, since the blade 21 is fixed to the rolling piston 12a, the contact portion between the blade and the rolling piston moves from the compression chamber I to the suction chamber H as in a conventional compressor. Gas is prevented from leaking, and the volumetric efficiency can be increased.

However, the configuration of the present embodiment is more preferably used for a so-called swing type compressor, and is sufficiently applicable to a conventional rotary compressor in which a blade and a rolling piston are separated. The occurrence of abnormal sound can be prevented.

In this embodiment, the two-cylinder rotary compressor shown in FIG. 1 has been described. However, the equations (1) and (2) are applied to the one-cylinder rotary compressor shown in FIG.
A configuration satisfying the above may be applied. In this case, 1
The next space volume [V1] is a volume of a space below the motor 4 and surrounded by the motor 4, the sealed container 1, and the upper surface level of the cylinder 9.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0077]

As described above, according to the rotary compressor according to the first aspect, the present inventors have found a relational expression capable of suppressing the occurrence 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 generation of abnormal noise without deteriorating the motor characteristics.

Further, according to the rotary compressor according to the second aspect, the rotary compressor satisfies the above relational expression and is further configured to shift the magnet center.
It is also possible to more effectively prevent the occurrence of abnormal sounds.

[Brief description of the drawings]

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

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

FIG. 3 is a graph showing a relationship between an operating frequency and a crank vertical 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 garner generating operation frequency and a theoretical resonance frequency in a two-cylinder rotary compressor.

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

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

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

[Explanation of symbols]

 DESCRIPTION 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

Claims (2)

[Claims] 1. A motorized element (4) arranged at an upper part in a closed container (1) and a motorized element (4) arranged at a lower part in the sealed container (1) and rotated by a rotating shaft (5). A compression element (13) coupled to said compression element (1).
3) a cylindrical cylinder (9a, 9b) and the electric element (4) disposed in the cylinder (9a, 9b).
Rotating pistons (12a, 12b) that rotate along the inner peripheral surface of the cylinders (9a, 9b) to compress the refrigerant gas by being given a rotational force through the rotating shaft (5).
A rotary compressor comprising: the electric element (4) surrounded by the electric element (4), the airtight container (1), and a 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)
And a second space (S) on the electric element (4) surrounded by
2) is V2, and the first and second spaces (S
1, S2), passage space (16, 17, 18a, 18)
b) The length 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) is N, and the number of rotations of the rotary pistons (12a, 12b) per unit time is the operating frequency. A rotary compressor characterized by satisfying the following relationship: 2. The electric element (4) includes a stator (2) having a stator core (2a) mounted in the closed container (1), and the electric element (4) is fixed to a central space of the stator (2). A rotor (3) arranged at a distance from an inner peripheral surface of the child (2), and an upper end of the rotor (3) protrudes upward from an upper end surface of the stator core (2a); The rotary compressor according to claim 1.