JP2010144517A - Hermetic compressor - Google Patents

Abstract

The present invention provides a hermetic compressor capable of suppressing unnecessary vibrations by regulating the balance weight trajectory and further improving the controllability of the movement of the center of gravity.
A hermetic compressor 100 includes a balance weight 7 attached to a lower end of a rotor 5 via a guide mechanism 10 and an elliptical cam mechanism 8 installed on a part of the outer periphery of a drive shaft bearing 4. And a spring 9 that presses the balance weight 7 against the cam surface 8 a of the cam mechanism 8, and makes it possible to change the position of the center of gravity of the balance weight 7 according to the rotation angle of the rotor 5. 2 to suppress fluctuations in rotational torque.
[Selection] Figure 2

Description

  The present invention relates to a hermetic compressor, and more particularly to a single rotary hermetic compressor.

  Conventionally, a hermetic compressor forms a space whose volume fluctuates by a fixed compression element and a movable compression element, compresses refrigerant gas in a stroke in which the volume decreases, and is compressed in a stroke in which the volume increases. In addition to discharging the refrigerant gas, the refrigerant gas (before being compressed) is newly sucked. For this reason, the pressure of space fluctuates with compression of refrigerant gas. That is, when rotating the compression element on the movable side, the torque required for the rotation fluctuates, and the rotational angular velocity fluctuates with the fluctuation of the torque, which causes the occurrence of vibration.

Accordingly, an invention is disclosed in which a balance weight (same as a balancer) is installed in a rotating part and centrifugal force due to the eccentric load is used to cancel the torque fluctuation.
For example, a dynamic vibration absorber made up of two pendulums is installed on the top of a rotor (connected to a movable compression element via a drive shaft to form an electric mechanism) and acts on the pendulum A compressor that cancels the torque fluctuation during one rotation by the centrifugal force is disclosed (for example, see Patent Document 1).
In addition, a rotary compressor is disclosed in which an annular groove is provided in the upper part of the rotor, and refrigeration oil is stored in the groove as the rotor rotates (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2005-201195 (page 12, FIG. 3-7) JP 59-176493 (page 3, FIG. 1-3)

  However, since the compressors disclosed in Patent Documents 1 and 2 move the center of gravity of the balance weight only by centrifugal force, there is a possibility that unnecessary vibration may occur depending on the operating frequency. In addition, since the trajectory of the center of gravity movement is not regulated or the trajectory is difficult to change, there is a problem that it is difficult to flexibly move the center of gravity with respect to torque fluctuations that vary according to the rotation angle.

  The present invention has been made to solve the above-described problems, and by controlling the balance weight trajectory, it is possible to suppress unnecessary vibration and to further improve the controllability of the movement of the center of gravity. You will get a chance.

An hermetic compressor according to the present invention includes an electric mechanism including a stator and a rotor,
A compression mechanism comprising a compression mechanism eccentric portion for compressing the refrigerant gas; and
A drive shaft connecting the rotor and the eccentric portion of the compression mechanism;
A drive shaft bearing that rotatably supports the drive shaft;
A balance weight installed on the rotor so that the distance from the center of rotation is variable;
A cam mechanism provided on an outer periphery of the drive shaft bearing and having a cam surface against which the balance weight is pressed;
Biasing means for pressing the balance weight against the cam surface;
The center of gravity position of the balance weight can be changed according to the rotation angle of the rotation shaft.

  The refrigerating and air-conditioning apparatus of the present invention can change the position of the center of gravity of the balance weight according to the rotation angle of the rotating shaft, that is, the trajectory (the same as the position of the center of gravity for each rotation angle) of the balance weight during one rotation is regulated. Therefore, the fluctuation | variation (same as the fluctuation | variation of a rotation angular velocity) of the rotation torque which generate | occur | produced by the pressure fluctuation | variation of the refrigerant gas which acts on a compression mechanism eccentric part can be suppressed.

[Embodiment 1]
1 to 4 illustrate a hermetic compressor according to Embodiment 1 of the present invention. FIG. 1 is a longitudinal sectional view showing the main part, FIG. 2 is a plan view showing the part, and FIG. FIG. 4 is a characteristic diagram showing the behavior during rotation. In the following description and drawings, the same or corresponding parts are denoted by the same reference numerals, and a part of the description is omitted.

(overall structure)
In FIG. 1, a hermetic compressor (hereinafter referred to as “compressor”) 100 includes a cylindrical hermetic container 11 made of a plate, an electric mechanism 12 disposed in an upper space in the cylindrical hermetic container 11, and a cylinder. And a rotary compression mechanism (hereinafter referred to as “compression mechanism”) 1 disposed in the lower space in the closed container 11.

(Electric element)
The electric mechanism 12 includes a rotor 5 and a stator 6, and the stator 6 is attached in an annular shape along the inner periphery of the upper space of the cylindrical hermetic container 11, and the rotor 5 is disposed inside the stator 6. They are arranged with a slight gap. The rotor 5 is integrally provided with a crankshaft (hereinafter referred to as “drive shaft”) 3 that extends in the vertical direction through the center thereof, and the drive shaft 3 is a drive shaft bearing that is fixed to a cylindrical sealed container 11. 4 is pivotally supported.

(Compression mechanism)
The compression mechanism 1 sucks and compresses refrigerant gas, and includes a compression element on the fixed side and a compression element 2 on the movable side (hereinafter referred to as “compression mechanism eccentric part”), and the compression mechanism eccentric part. 2 is connected to the drive shaft 3 and is rotationally driven by the electric mechanism 12.

(Exercise control means)
Further, a balance weight 7 for balancing the center of gravity with the compression mechanism eccentric portion 2 is attached to the lower end of the rotor 5. That is, the balance weight 7 is guided by a guide mechanism 10 provided at the lower end of the rotor 5 so as to be movable in the direction away from the rotation center (same as the radial direction), and is biased toward the rotation center by the spring 9. Yes. The spring 9 exhibits a force that can overcome the centrifugal force acting on the balance weight 7 when the rotor 5 rotates.
On the other hand, an elliptical cam mechanism 8 protruding in a direction away from the rotation center of the drive shaft 3 is attached to a part of the outer periphery of the drive shaft bearing 4, and the surface of the balance weight 7 on the rotation center side (hereinafter referred to as “contact”). 7 a is in contact (sliding) with the cam surface 8 a of the cam mechanism 8.
Accordingly, since the balance weight 7 is urged toward the center of rotation by the spring 9, while the contact surface 7 a of the balance weight 7 is in contact (sliding) with the cam surface 8 a of the cam mechanism 8, While the distance from the rotation center fluctuates along the shape of the surface 8a, while the abutting (sliding) on the outer periphery 4a of the drive shaft bearing 4, the distance from the rotation center is along the cylindrical surface. It will be kept constant.

(Operation)
Next, the operation of the balance weight 7 will be described.
3 (a) to 3 (h), for the convenience of the following description, it is assumed that the rotor 5 rotates in the clockwise direction, and the rotation start position is referred to as an upward direction in the drawing (hereinafter referred to as “12 o'clock direction”). ) And the position where the cam surface 8a of the cam mechanism 8 is farthest from the center of rotation is the right direction in the figure (hereinafter referred to as “3 o'clock direction”).
3A, when the rotor 5 is at the 12 o'clock position (the rotation angle is the same as 0 °), the contact surface 7a of the balance weight 7 is in contact with the outer periphery 4a of the drive shaft bearing 4 (sliding). The balance weight 7 is located closest to the center of rotation.

  3 (b) to 3 (d), the contact surface 7a of the balance weight 7 contacts (slids) the cam surface 8a of the cam mechanism 8 due to the rotation of the rotor 5 (same as the rotation angle increases). The balance weight 7 is furthest away from the center of rotation when the rotor 5 is rotated by a quarter circle (the rotation angle is the same as 90 °). (See (d)). During this time, the angle (θ) formed by the line connecting the center of gravity of the balance weight 7 and the center of rotation and the perpendicular of the contact surface 7a (same as the biasing direction of the spring 9) varies.

  Further, in FIGS. 3E to 3G, due to the rotation of the rotor 5, the contact surface 7a of the balance weight 7 gradually approaches the center of rotation, and the rotor 5 rotates by 1/2 circle. When the rotation angle is the same as 180 °, the balance weight 7 is closest to the rotation center (see (g) of FIG. 3). During this time, the angle (θ) formed by the line connecting the position of the center of gravity of the balance weight 7 and the center of rotation and the perpendicular of the contact surface 7a varies.

  Further, while the rotor 5 is rotating from the half circle to the original position (the rotation angle is the same as 180 ° to 360 °), the contact surface 7a of the balance weight 7 is the outer periphery 4a of the drive shaft bearing 4. Since the distance from the center of rotation does not vary with rotation, the balance weight 7 is located closest to the center of rotation (see (h) of FIG. 3).

  As described above, in the compressor 100, the center of gravity of the balance weight 7 moves (the distance from the rotation center varies) according to the rotation angle of the rotor 5. And the centrifugal force for each rotation angle of the compression mechanism eccentric part) and the rotational torque due to the gas load in the compression chamber (formed by the fixed compression element and the movable compression element) at the same rotation angle. can do.

In FIG. 4, the vertical axis represents the centrifugal force acting on the rotating part and the gas load in the compression chamber, normalized to 1 at the maximum, and the horizontal axis represents the rotation of the rotor 5 (same as the balance weight 7). It is an angle (in the figure, it is a crank angle).
That is, the center of gravity of the balance weight moves corresponding to the rotation angle at which the gas pressure in the compression chamber fluctuates, and the centrifugal force acting on the balance weight is applied to the compression chamber gas load (the load that compresses the refrigerant gas in the compression chamber). It is shown to be balanced with the resulting rotational torque. Therefore, the load of the electric element is leveled and fluctuations in the rotational angular velocity of the rotating part are suppressed, so that unnecessary vibrations are prevented from occurring.

As described above, since the compressor 100 can control the position of the center of gravity during one rotation of the drive shaft 3 of the compression mechanism 1, the rotation angle by gas compression or the like generated in accordance with the rotation angle during one rotation. The balance can be canceled, and the center-of-gravity movement locus can be changed in accordance with the state of occurrence of the rotational imbalance.
In the present invention, the cam surface 8a of the cam mechanism 8 is not limited to an elliptical shape, and the contact surface 7a of the balance weight 7 is not limited to a flat surface. It is possible to obtain an appropriate shape for realizing the above. Further, the configuration of the guide mechanism 10 and the form of the spring 9 are not limited.

  According to the present invention, useless vibration can be suppressed with a simple configuration, and therefore it can be widely used as various compressors for home use and business use.

The longitudinal cross-sectional view which shows the principal part explaining the hermetic compressor which concerns on Embodiment 1 of this invention. The top view which shows the part of the hermetic compressor shown in FIG. The top view which shows operation | movement of the balance weight installed in the hermetic compressor shown in FIG. The characteristic view which shows the behavior at the time of rotation of the hermetic compressor shown in FIG.

Explanation of symbols

  1: compression mechanism, 2: compression mechanism eccentric part, 3: drive shaft, 4: drive shaft bearing, 4a: outer periphery of drive shaft bearing, 5: rotor, 6: stator, 7: balance weight, 7a: balance weight 8: cam mechanism, 8a: cam surface, 9: spring, 10: guide mechanism, 11: cylindrical sealed container, 12: electric mechanism, 100: hermetic compressor.

Claims (3)

An electric mechanism comprising a stator and a rotor;
A compression mechanism comprising a compression mechanism eccentric portion for compressing the refrigerant gas; and
A drive shaft connecting the rotor and the eccentric portion of the compression mechanism;
A drive shaft bearing that rotatably supports the drive shaft;
A balance weight installed on the rotor so that the distance from the center of rotation is variable;
A cam mechanism provided on an outer periphery of the drive shaft bearing and having a cam surface against which the balance weight is pressed;
Biasing means for pressing the balance weight against the cam surface;
A hermetic compressor, wherein the position of the center of gravity of the balance weight can be changed according to the rotation angle of the rotation shaft. The cam mechanism has an elliptical cam surface;
The balance weight has a flat contact surface that contacts the cam surface,
2. The hermetic compression according to claim 1, wherein an angle formed between a line connecting the center of gravity of the balance weight and the rotation center and the contact surface varies with a rotation angle of the rotor. Machine.   3. The hermetic compressor according to claim 1, wherein the biasing means is a spring attached to a guide mechanism that guides the balance weight so that the distance from the rotation center is variable.

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