JP4019205B2 - Hermetic compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hermetic compressor used in a refrigerator, a room air conditioner, and the like, and more particularly to a hermetic compressor having a scotch yoke type piston reciprocating mechanism that can reduce a load applied to a rotary bearing portion in a compression process.
[0002]
[Prior art]
A slider mechanism of a conventional hermetic compressor will be described with reference to FIGS. 9 and 10. FIG. 9 is a longitudinal sectional view of the compressor, and FIG. 10 is a perspective view of the slider. In FIG. 9, a cylinder 9 and a piston 10 that constitute a compression portion are installed at the upper part of a frame 7, and a stator 4 and a rotor 5 that constitute an electric motor element are installed at the lower part. The crankshaft 6 is integrally formed with an eccentric shaft 6b having an axis 6c at a position eccentric from the rotation center shaft 6a, and the eccentric shaft 6b passes through the through hole of the slider 8. The crankshaft 6 is directly connected to the rotor 5 through the rotary bearing portion 7 a of the frame 7, and the piston 10 passes through the slider 8 that slides on the inner diameter of the slide tube 10 a of the piston 10 as the rotor 5 rotates. It is the structure which reciprocates.
Further, as shown in FIG. 10, the slider 8 has a symmetrical shape, and has a through hole 8a through which the crankshaft eccentric shaft 6b passes in the center, and the center of gravity of the slider 8 is the center of the eccentric shaft 6b. It exists on the axis 6c.
A known example of this type of compressor is Japanese Utility Model Publication No. 62-40133.
[0003]
[Problems to be solved by the invention]
FIG. 11 shows a state diagram of force during compression of the conventional example. In FIG. 11, the crankshaft 6 is tilted by the gas compression load Fg, and the crankshaft 6 is locally in contact with the upper end portion 7b and the lower end portion 7c of the bearing portion 7a of the frame 7, and the oil film runs out and abnormal wear occurs. May cause. Therefore, when the pressure in the cylinder rises during the compression process and a large gas compression load is applied to the crankshaft eccentric shaft 6b at the piston tip, it is necessary to reduce the load and reduce the load applied to the bearing portion. This method includes increasing the weight of the piston and slider.
[0004]
However, in this method, the angle of the crankshaft where the piston is located at the top dead center is 0 degree, the angle when the piston is located at the bottom dead center is 180 degrees, the suction process is 0 to 180 degrees, and the compression process is 180 to 360. In this case, it may be possible to reduce the load at the crankshaft angle where the maximum load is applied from around 330 degrees to 360 degrees, but when the gas load near the bottom dead center is small, the inertial force is eccentric to the crankshaft. It works greatly on the shaft 6b, and as a result, the average value of the load applied from the top dead center to the bottom dead center increases, the load on the bearing portion increases, the input of the motor increases, and eventually the reliability of the hermetic compressor There was a drawback of reducing the properties.
[0005]
It is an object of the present invention to reduce the load applied to the eccentric shaft and the bearing in the compression process where the maximum load is applied without increasing the weight of the piston and the slider in the hermetic compressor, and to improve the reliability of the hermetic compressor. Is to improve the performance.
[0006]
[Means for Solving the Problems]
The present invention achieves the above object as follows.
Basically, it has a slide tube and a slider that can move in the slide tube, the slider is provided on an eccentric shaft of a crankshaft, and the slide tube is provided on a piston that can reciprocate in a cylinder. In a hermetic compressor having a scotch yoke type piston reciprocating mechanism in which the piston reciprocates by rotation of the shaft, the center of gravity of the slider is separated from the axis of the eccentric shaft of the crankshaft. is there. That is, by separating the center of gravity of the slider from the axis of the eccentric shaft , the inertial force of the slider increases when the crankshaft is rotated, and this slider inertial force can be applied in the direction opposite to the gas compression direction. The load applied to the eccentric shaft of the crankshaft can be reduced. In this case, in the compression process of the piston, the minimum distance connecting the center axis of the crankshaft and the center of gravity of the slider is set to be smaller than the minimum distance from the center axis of the crankshaft to the axis of the eccentric shaft. it can be long Kusuru. According to this, the slider center of gravity position is farther from the center axis of rotation of the crankshaft than the center axis of the eccentric shaft , so the inertial force of the slider is opposite to the direction of the load due to gas compression. Can be made to act greatly. Furthermore, in this case, when the rotation angle of the crankshaft is 0 degree at the top dead center of the piston, 180 degrees at the bottom dead center, 0 to 180 degrees for the suction process, and 180 to 360 degrees for the compression process, In the process of 270 to 360 degrees in the compression process, the minimum distance connecting the center axis of the crankshaft and the center of gravity of the slider is set to be smaller than the minimum distance from the center axis of the crankshaft to the axis of the eccentric shaft. it can be long Kusuru. According to this, at a crankshaft angle of 270 to 360 degrees at which the gas compression load increases, the distance from the crankshaft rotation center axis to the slider center of gravity increases, and the inertial force is the square of the slider mass, distance, and rotation angular velocity. Since the inertial force is greatly increased in the opposite direction of the gas compression load at the crankshaft rotation angle of 270 to 360 degrees by increasing the distance to the center of gravity, the piston of the load applied to the eccentric shaft of the crankshaft The maximum value of the force in the reciprocating direction component can be reduced .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same structure part as a prior art example.
FIG. 1 and FIG. 2 are views showing an embodiment of the present invention. FIG. 1 is a plan view illustrating a difference between a gravity center position 2 of a slider 1 and a gravity center position 3 of a conventional slider in the present embodiment. FIG. 2 is a perspective view of the slider 1 of the embodiment of FIG. As shown in these drawings, in the present embodiment, the eccentric shaft 6b of the crankshaft passes through the through hole 1a formed in the central portion of the slider 1, but the slider 1 is partially removed from the mass. The slider center of gravity position 2 is offset from the center of the slider and is also offset from the eccentric shaft center 6c. The conventionally known slider center-of-gravity position 3 coincides with the eccentric shaft axis 6c.
[0008]
FIG. 3 shows the locus of the slider center of gravity when the suction process is 0 to 180 degrees and the compression process is 180 to 360 degrees. That is, the trajectory B is a trajectory in which the conventionally known slider center-of-gravity position 3 rotates about the crankshaft rotation center axis 6a. The locus A shows the case of the present embodiment, and in the compression process, the minimum distance connecting the crankshaft rotation center axis 6a and the slider center of gravity position 2 is the minimum distance between the crankshaft rotation center axis 6a and the eccentric axis 6c. The slider center-of-gravity position 2 is arranged at a longer position, and the locus when the slider center-of-gravity position 2 is rotated about the crankshaft rotation center axis 6a is shown.
[0009]
FIG. 4 is a graph showing a change in load applied to the piston tip due to in-cylinder gas compression at a crankshaft angle of 0 to 360 degrees.
FIG. 5 shows a case where the center of gravity of the slider in the present embodiment draws the locus A shown in FIG. It is a graph showing the comparison of a piston reciprocating direction component.
FIG. 6 shows the piston reciprocating direction component of the load applied to the eccentric shaft of the crankshaft, comparing the product of the present invention with the conventional product, and showing the direction of the vertical axis as the direction of the load by gas compression.
FIG. 7 shows a comparison between the product of the present invention and the conventional product regarding the resultant force between the piston reciprocating direction component of the load applied to the eccentric shaft of the crankshaft and the vertical direction component with respect to the piston reciprocating direction. It is shown as a direction.
[0010]
Next, the embodiment of FIG. 1 will be described with reference to these drawings.
According to the embodiment of FIG. 1, the center of gravity position 2 of the slider is shifted from the reciprocating direction of the piston 10 on the left-right direction and the piston reciprocating cylinder side by 5 mm in this embodiment. When the crankshaft 6 rotates clockwise, as shown in FIG. 3, the crankshaft rotation angle at which the gas compression load increases is 270 to 360 degrees (see FIG. 4), and from the crankshaft rotation center axis 6a to the slider center of gravity 2 Is longer than the distance from the crankshaft rotation center axis 6a to the eccentric axis 6c. Since the inertial force is the product of the slider mass, the distance, and the square of the rotational angular velocity, the inertial force increases at a crankshaft rotational angle of 270 to 360 degrees as the distance to the center of gravity increases.
[0011]
As shown in FIG. 5, this is also evident in the comparison of the inertial force between the product of the present invention and the conventional product. It can be seen that the inertia force is greatly increased in the opposite direction. Therefore, the force in the opposite direction to the gas compression load is increased, and the maximum value of the force in the piston reciprocating direction component of the load applied to the crankshaft eccentric shaft can be reduced as shown in FIG.
[0012]
In FIG. 7, the resultant force of the piston reciprocating direction applied to the crankshaft eccentric shaft and the force perpendicular to the piston reciprocating direction increases the slider inertia force. It can be said that the inertial force component in the direction perpendicular to the piston reciprocating direction increases. The inertia force becomes dominant during the suction process with a small gas compression load, and in the suction process, the load applied to the eccentric shaft of the crankshaft in the product of the present invention is larger than that of the conventional product, but the maximum load is applied. During the compression process, the piston reciprocating direction component of the slider inertia force works effectively to reduce the load, and the average value of the load applied to the eccentric shaft of the crankshaft is about 6. It is reduced by about 7%.
[0013]
Next, another embodiment of the present invention will be described.
FIG. 8 is a diagram showing another embodiment of the present invention. In this embodiment, the basic shape is the same as that of the conventional slider (see FIG. 10), but the position of the through hole 1a through which the crankshaft eccentric shaft 6b passes is moved in a direction perpendicular to the piston reciprocating direction. It is. At this time, the center-of-gravity position 2 of the slider is on the opposite side of the through-hole 1a (eccentric axis 6c) with respect to the center-of-gravity position 3 of the conventional slider.
[0014]
According to this example, the rotation of the crankshaft 6 is clockwise, and the range in which the maximum gas compression load works is in the range of 270 to 360 degrees shown in FIG. 3, and in this range, the slider inertia force becomes large. The slider 2 is arranged so that the distance between the crankshaft rotation center axis 6a and the slider center-of-gravity position 2 is longer than the minimum distance connecting the crankshaft rotation center axis 6a and the crankshaft eccentric shaft axis 6c. As a result, the inertial force acting as a force opposite to the gas compression load in the compression process can be increased, so that the maximum value and the average value of the load applied to the crankshaft eccentric shaft 6b are reduced, and the reliability of the hermetic compressor is reduced. Can be improved. Further, in the present embodiment, only the through hole of the slider is moved and no processing work is added, so that the cost is not increased.
[0015]
In the present invention, the method for shifting the center of gravity of the slider from the eccentric shaft axis is not limited to the above embodiment. There are various methods such as a method for shifting the mounting position of the slider with respect to the eccentric shaft center, a method for processing the slider itself asymmetrically, and a method for adding or reducing mass to a part of the slider.
[0016]
As described above, according to the present invention, when the rotary motion about the rotation center axis of the crankshaft is performed, the slider generates an inertial force centered on the rotation center axis. The inertial force is applied in the direction opposite to the gas compression load when a large gas compression load in the compression process is applied, and has the effect of relaxing the load on the eccentric shaft of the crankshaft. is there. Such knowledge has led to the creation of a hermetic compressor in which the inclination due to the crankshaft load is suppressed, the load applied to the bearing is reduced, and the reliability is improved.
[0017]
【The invention's effect】
According to the present invention, in a hermetic compressor including a scotch yoke type piston reciprocating mechanism, the crankshaft and the bearing are protected against the maximum load generated by gas compression by shifting the eccentric shaft of the crankshaft and the center of gravity of the slider. Therefore, the reliability of the hermetic compressor can be improved.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of the present invention.
FIG. 2 is a perspective view of the slider in FIG.
FIG. 3 is a diagram illustrating the locus of the center of gravity of each slider according to the related art and the present embodiment.
FIG. 4 is a diagram showing a change in load due to gas compression.
FIG. 5 is a diagram showing a comparison of piston reciprocating direction components of slider inertia force of the present embodiment and a conventional slider.
FIG. 6 is a diagram showing a comparison of piston reciprocating direction components of a load applied to the eccentric shaft of the present embodiment and a conventional crankshaft.
FIG. 7 is a diagram showing a comparison of resultant force between a piston reciprocating direction component of a load applied to the eccentric shaft of the present embodiment and a conventional crankshaft and a component in a direction perpendicular to the piston reciprocating direction.
FIG. 8 is a diagram showing another embodiment of the present invention.
FIG. 9 is a longitudinal sectional view showing a conventional hermetic compressor.
FIG. 10 is a diagram showing a conventional slider.
FIG. 11 is a view showing a state in which the crankshaft is tilted by a load due to compression.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Slider 1a Through-hole 1b Weight adjustment part 2 Slider center-of-gravity position 3 In the present invention Slider center-of-gravity position 4 Stator 5 Rotor 6 Crankshaft 6a Crankshaft rotation center shaft 6b Crankshaft eccentric shaft 6c Crankshaft eccentric shaft Core 7 Frame 7a Bearing portion 7b Bearing upper end portion 7c Bearing lower end portion 8 Slider 8a Through hole 9 Cylinder 10 Piston 10a Slide tube A Trajectory drawn by slider center of gravity in the present invention B Trajectory drawn by slider center of gravity in conventional example

Claims (2)

A slide tube and a slider movable within the slide tube, the slider being provided on an eccentric shaft of a crankshaft, the slide tube being provided on a piston capable of reciprocating in a cylinder, and the rotation of the crankshaft In a hermetic compressor equipped with a Scotch yoke type piston reciprocating mechanism in which the piston reciprocates,
The slider, the center of gravity of the slider is formed apart from the axis of the eccentric shaft of prior SL crankshaft, the compression process of the piston, the minimum distance connecting the center of gravity of the central shaft and the slider of the crankshaft, A hermetic compressor, characterized in that it is longer than the minimum distance from the center axis of the crankshaft to the axis of the eccentric shaft . The hermetic compressor according to claim 1, wherein
When the rotation angle of the crankshaft is 0 degrees at the top dead center of the piston, 180 degrees at the bottom dead center, 0 to 180 degrees for the suction process, and 180 to 360 degrees for the compression process, 270 of the compression process. In the process of ˜360 degrees, the minimum distance connecting the center axis of the crankshaft and the center of gravity of the slider is longer than the minimum distance from the center axis of the crankshaft to the axis of the eccentric shaft. Hermetic compressor.

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