JP2006316795A - Hermetic electric compressor and refrigerator using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hermetic electric compressor capable of achieving high efficiency and reducing vibration and noise by using a refrigerant containing R600a mainly. <P>SOLUTION: In this reciprocating type hermetic electric compressor of inverter driving type driven by a plurality of operation frequencies including rotational speed being less than commercial power supply frequency by using the refrigerant formed by R600a mainly and containing hydrocarbon refrigerant as a main component, a ratio of outside diameter to reciprocating movement of a piston 130 is within a scope of 1 : 1 to 1.5 : 1, a compression element 106 is constructed substantially above an electric element 105, and the compression element 106 is elastically supported from a sealed vessel 101 below a stator 103 through the stator 103 to suppress vibration at compression time to small extent and suppress leakage between a compression chamber 122 and the piston 130 to small extent so that the hermetic electric compressor capable of achieving high efficiency and reducing vibration and noise can be realized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hermetic compressor used in an electric refrigerator, an air conditioner, a vending machine, or the like.

  In recent years, the demand for the global environment has been increasing, and movements such as energy conservation and regulation of gases with high greenhouse effects have been accelerated.

  Hereinafter, the above-described hermetic electric compressor will be described with reference to the drawings. In the following description, the upper and lower relationships are based on a state in which the hermetic electric compressor is installed in a normal posture.

  FIG. 4 is a cross-sectional view of a prior art hermetic electric compressor described in Patent Document 1, and 1 is a hermetically sealed container for storing refrigeration oil 2. An electric element 5 includes a stator 3 and a rotor 4 incorporating a permanent magnet. Reference numeral 6 denotes a compression element, which is constructed below the electric element 5, is driven by the electric element 5, and is housed in the sealed container 1.

  Further, this hermetic electric compressor is designed to compress R134a, which is a typical HFC refrigerant having an ozone depletion coefficient of zero.

  Next, details of the compression element 6 will be described below.

  Reference numeral 10 denotes a crankshaft, which has a main shaft portion 11 in which the rotor 4 is press-fitted and fixed, and an eccentric portion 12 formed eccentrically with respect to the main shaft portion 11. Reference numeral 20 denotes a cylinder block having a substantially cylindrical compression chamber 22 and a bearing portion 23 that supports the main shaft portion 11 and is formed below the electric element. A piston 30 is fitted into the compression chamber 22 and is connected to the eccentric portion 12 by a connecting means 31. Reference numeral 33 denotes a balance weight in which iron plates are laminated, and is fixed to the rotor 4. Reference numeral 35 denotes a valve plate for sealing the end face of the compression chamber 22, and reference numeral 36 denotes a high pressure chamber formed by a head, which is fixed to the side opposite to the compression chamber 22 of the valve plate 35.

  Reference numeral 39 denotes a suction tube fixed to the sealed container 1 and connected to the low-pressure side (not shown) of the refrigeration cycle, and guides a refrigerant gas (not shown) into the sealed container 1. Reference numeral 40 denotes a suction muffler that forms a silencing space 42. 50 is fitted between a snubber bar 52 fixed to the sealed container 1 by a suspension spring and a snubber bar portion 53 formed in the cylinder block 20 to elastically support the compression element 6.

  Reference numeral 60 denotes an inverter device connected to the stator 3. 61 is a control circuit for controlling the inverter device 60, 62 is a commercial power supply, and is connected to the control circuit 61 and the inverter device 60.

  In general, the power consumption of a compressor becomes smaller as the operating frequency is lower, and the refrigeration capacity corresponding to the load is also required at the same time. A plurality of output frequencies are arbitrarily set within a range exceeding the frequency.

  Next, a series of operations in the above configuration will be described.

  The electric power supplied from the commercial power source 62 is supplied to the electric element 5 via the control circuit 61 and the inverter device 60, and the rotor 4 of the electric element 5 is rotated at an arbitrary rotation speed. The rotor 4 rotates the crankshaft 10, and the eccentric motion of the eccentric portion 12 drives the piston 30 via the connecting means 31, so that the piston 30 reciprocates in the compression chamber 22 and passes through the suction tube 39. The refrigerant gas introduced into the inside is sucked from the suction muffler 40 and continuously compressed in the compression chamber 22.

At this time, the vibration generated by the reciprocating motion of the piston 30 is considerably canceled by the balance weight 33, but a part remains. The vibration remaining in this way causes the cylinder block 20 to vibrate as a reaction, and this vibration is further damped by the suspension spring 50. The amplitude of the vibration of the hermetic electric compressor generated at this time increases as the rotational speed of the electric element decreases, but at an operating frequency of around 27 Hz, the level is about 32 μm, which is less than 40 μm, which is practically not problematic. It was.
JP 11-107931 A

  The above-described hermetic electric compressor has a general configuration already in practical use, but still has room for improvement from the viewpoint of the global environment.

  That is, the hermetic electric compressor of the prior art is designed to compress R134a, which is a typical HFC refrigerant having an ozone depletion coefficient of zero, but the HFC refrigerant containing R134a has a warming coefficient. It is decided that it will be regulated soon. Instead, a hydrocarbon-based refrigerant that has already been put to practical use in Europe and has an ozone depletion coefficient of zero and a low global warming coefficient, specifically R600a, is considered to be an effective alternative refrigerant in Japan.

  However, R600a has only about half the refrigeration capacity per compressor suction volume compared to refrigerant R134a. From this, in order to obtain the same refrigeration capacity as R134a, the displacement volume by the piston is expanded to nearly twice that of R134a. There is a need to.

  Usually, in order to increase the displacement volume (hereinafter referred to as cylinder volume), the diameter of the compression chamber, that is, the outer diameter of the piston is increased, the eccentric amount of the crankshaft shaft is increased, or both of them are used in combination. However, increasing the outer diameter of the piston increases the mass of the piston, and increasing the eccentric amount of the crankshaft increases the acceleration in the reciprocating motion of the piston. When either of these methods is adopted, vibration energy associated with the reciprocation of the piston increases. In particular, when the cylinder volume is increased to nearly twice, this vibration energy becomes very large.

  On the other hand, the amplitude of the vibration of the compressor generated by this vibration energy becomes larger as the rotational speed of the electric element is lower due to the relationship between the inertial mass of the compression element or electric element and the vibration energy. At low speed operation using an inverter device, specifically at a rotational frequency around 27 Hz, vibration increases to a level of about 65 microns. At these amplitude levels, the noise generated by the compressor and the refrigeration system increases with this vibration, and the refrigerant leaks because the piping of the refrigeration system is fatigued and broken by vibration. There is a problem such as.

  The present invention solves these problems, and provides a hermetic electric compressor that uses a refrigerant mainly composed of R600a, provides high efficiency, low vibration, and low noise, and has low noise and reliability. It aims at providing a high freezing apparatus.

  In order to solve the above-described conventional problems, the hermetic electric compressor of the present invention uses a refrigerant mainly composed of hydrocarbon refrigerant mainly composed of R600a, and has a plurality of operating frequencies including a rotational speed less than the commercial power frequency. An inverter driven reciprocating hermetic electric compressor to be driven, wherein a ratio of an outer diameter of the piston to a reciprocating motion is in a range of 1: 1 to 1.5: 1, and the compression element is the electric motor. It is constructed substantially above the element, and the compression element is elastically supported from the hermetic container below the stator via the stator, and vibration during compression is suppressed, and the compression chamber and piston It has the effect that leakage between the two is suppressed to a small level.

  The hermetic electric compressor according to the present invention suppresses vibration during compression and suppresses leakage between the compression chamber and the piston, so that the hermetic electric compressor is highly efficient, has low vibration, and is low in noise. Can be realized.

  According to the first aspect of the present invention, a refrigerating machine oil, a compression element including a piston that reciprocates in a compression chamber, and an electric element that includes a stator and a rotor and drives the compression element are housed in a sealed container. , An inverter-driven reciprocating hermetic electric compressor that uses a refrigerant mainly composed of a hydrocarbon refrigerant mainly composed of R600a and is driven at a plurality of operating frequencies including a rotational speed less than a commercial power frequency, The ratio of the outer diameter of the piston to the reciprocation is in the range of 1: 1 to 1.5: 1, the compression element is constructed substantially above the electric element, and the compression element is interposed via the stator. The hermetic electric compressor is elastically supported from the hermetic container under the stator, and vibration during compression is suppressed, and leakage between the compression chamber and the piston is suppressed to be small. And shake Is small, it can be realized with low noise hermetic electric compressor.

  The invention according to claim 2 is driven at an operating frequency including a rotational speed of at least 27 Hz in the invention according to claim 1, and further sealed in addition to the effect of the invention according to claim 1. The power consumption of the type electric compressor can be reduced.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the clearance between the compression chamber and the piston is in the range of 5 to 10 microns, and the compression chamber and the piston In addition to the effect of the invention according to claim 1, higher efficiency can be realized.

  The invention according to claim 4 is the invention according to claim 1 or 2, wherein the refrigerating machine oil has a viscosity at 40 degrees C within a range of 7 to 32 cSt. In addition to the effects of the invention described in claim 1 or 2, higher efficiency can be realized.

  The invention according to claim 5 includes a compressor, a condenser, a dryer, an expander, and an evaporator, and the hermetic electric compressor according to any one of claims 1 to 4 in the compressor. Since the vibration of the compressor is small, the noise of the refrigeration apparatus is kept low and the pipe breakage is less likely to occur, so that a highly reliable refrigeration apparatus can be realized.

  The invention according to claim 6 is the invention according to claim 5, wherein each of the compressor, the condenser, the dryer, the expander, and the evaporator is connected by piping by welding including brazing. In addition to the effects of the invention described in claim 5, the occurrence of cracks in the brazed portion due to fatigue is further suppressed, and a highly reliable refrigeration apparatus can be realized.

  Hereinafter, embodiments of a hermetic electric compressor according to the present invention will be described with reference to the drawings. In addition, about the same structure as a prior art example, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a hermetic electric compressor according to Embodiment 1 of the present invention, and FIG. 2 is a vibration characteristic diagram showing a relationship between operating frequency and compressor amplitude.

  In FIG. 1, 101 is an airtight container and stores the refrigerating machine oil 102. An electric element 105 includes a stator 103 and a rotor 104 having a permanent magnet. A compression element 106 is constructed above the electric element 105, is driven by the electric element 105, and is housed in the sealed container 101. In addition, this hermetic electric compressor compresses R600a, which is a typical refrigerant of a hydrocarbon refrigerant having a low warming potential.

  Details of the compression element 106 will now be described.

  Reference numeral 110 denotes a crankshaft, which has a main shaft portion 111 into which the rotor 4 is press-fitted and an eccentric portion 112 formed eccentrically with respect to the main shaft portion 111. A cylinder block 120 includes a substantially cylindrical compression chamber 122 and a bearing portion 123 that supports the main shaft portion 111, and an electric element is formed below. A piston 130 is fitted into the compression chamber 122 and is connected to the eccentric portion 112 by a connecting means 131. In order to obtain the refrigerating capacity equivalent to R134a employed in the conventional example with R600a, the eccentric amount of the eccentric portion 112 and the outer diameter of the piston 130 are far larger than those of the conventional example.

  133 is fixed to the rotor 104 by a balance weight in which iron plates are laminated. Reference numeral 135 denotes a valve plate that seals the end face of the compression chamber 22, and 136 denotes a high-pressure chamber formed by a head, which is fixed to the anti-compression chamber 122 side of the valve plate 135. Reference numeral 139 denotes a suction tube fixed to the sealed container 1 and connected to the low pressure side (not shown) of the refrigeration cycle, and guides a refrigerant gas (not shown) into the sealed container 101. Reference numeral 140 denotes a suction muffler that forms a silencing space 142.

  A suspension spring 150 is provided at four locations centering on the cross section of FIG. 1, and is fitted between a snubber bar 152 fixed to the hermetic container 101 and a snubber bar 153 fixed to the stator 103 of the electric element 105. The element 106 is indirectly elastically supported via the stator 103 of the electric element 105.

  The operation of the hermetic electric compressor configured as described above will be described below.

  The electric power supplied from the commercial power source 62 is supplied to the electric element 105 via the control circuit 61 and the inverter device 60, and the rotor 104 of the electric element 105 is rotated at an arbitrary rotation speed. The rotor 104 rotates the crankshaft 110, and the movement of the eccentric portion 112 is transmitted to the piston 130 via the connecting means 131, so that the piston 130 reciprocates in the compression chamber 122 and passes through the suction tube 139 and enters the sealed container 101. The refrigerant gas led to the suction is sucked from the suction muffler 140 and continuously compressed in the compression chamber 122.

  At this time, the vibration generated by the reciprocating motion of the piston 130 is considerably canceled by the balance weight 133, but a part remains. The remaining vibration causes the cylinder block 20 to vibrate as a reaction, but the eccentric amount of the eccentric portion 112 and the outer diameter of the piston 130 are much larger than those of the hermetic electric compressor shown in the conventional example compressing the refrigerant R134a. Therefore, the vibration energy generated by the reciprocating motion of the piston 130 is much larger than that shown in the conventional example, and the cylinder block 120 vibrates greatly as a reaction.

  However, the behavior of this vibration is completely different between the upper portion of the compression element 106 and the vicinity of the suspension spring 150. That is, although the vicinity of the cylinder block 120 that directly receives the reaction of the piston 130 vibrates greatly, in the vicinity of the suspension spring 150, this movement is supported downward via the electric element 105. Get smaller. This reduced amplitude is further damped by the suspension spring 150.

  As described above, the vibration amplitude of the hermetic electric compressor generated by the inertial energy due to the reciprocating motion of the piston becomes larger as the rotational speed of the electric element is lower. However, according to the present embodiment, the rotation around 27 Hz is performed. The frequency was found to be within a level of 40 micrometers or less, which is practically acceptable.

  As a verification result of the mechanism, the vibration characteristic diagram of FIG. 2 will be used.

  In FIG. 2, B is the result of the compressor shown in the conventional example, the cylinder volume is 5.7 cm 3, and R134a is used as the refrigerant. C is the same as the conventional example, with the cylinder volume expanded to 10 cm3 and measured using R600a as the refrigerant. A is the compressor according to the embodiment of the present invention, and the cylinder volume is also expanded to 10 cm3 and R600a is used as the refrigerant. It was measured using.

  The vibration value is the result of measuring the vibration in the lateral direction in the vicinity of the center of the compressor. From these results, B had a vibration at 27 Hz of 32 μm, C had a vibration at 27 Hz of 65 μm, and D had a vibration at 27 Hz of 29 μm.

  As is apparent from the above measured data, in the present invention, a vibration value almost equivalent to that of the compressor using the conventional R134a can be obtained, and low speed operation by the inverter device can be realized while using the refrigerant R600a. did it.

  At this time, even in the efficiency of the compressor that was continuously evaluated, a good result was obtained in which the COP at a rotation frequency around 25 Hz exceeded 1.3. The refrigerating machine oil used in this verification test is an alkylbenzene type refrigerating machine oil already in practical use in Europe and the like, and has a viscosity of 10 cSt at 40 ° C. Normally, when the compressor is operated at a low rotational speed, the amount of work of the compressor is small. As a result, the amount of heat generated from the compressor is small, and the temperature of refrigeration oil that is strongly affected by this heat in a sealed container is also small. .

  In the present embodiment, the refrigerating machine oil having a relatively low viscosity suppresses the viscous resistance at the sliding portion of the compressor, and the temperature rise is small under the low rotation operation, so that the space between the compression chamber 122 and the piston 130 is low. It is presumed that a good efficiency result was obtained by a synergistic effect that the leakage of the water was suppressed to a small level. From the above results, it is inferred that good efficiency results can be obtained if the viscosity is in the range of 7 to 32 cSt. In addition, the evaluated compressor has a clearance between the compression chamber 122 and the piston 130 of 5 to 10 microns, which is also a factor for suppressing leakage between the compression chamber 122 and the piston 130. Conceivable.

  In addition, the ratio of the piston outer diameter to the reciprocating distance is about 1.5 to 1, and the evaluated compressor keeps the piston outer diameter relatively small between the compression chamber 122 and the piston 130. It is considered that the leakage is suppressed to a low level, and it is estimated that a better efficiency result can be obtained by lowering this ratio to the vicinity of a normally designed ratio of about 1: 1.

(Embodiment 2)
FIG. 3 is a block diagram of a refrigeration apparatus according to Embodiment 2 of the present invention. In FIG. 3, 170 is a compressor, 180 is a condenser, 185 is a dryer, 187 is an expander, 189 is an evaporator, and each is fluidly connected by piping by welding such as brazing. The compressor 170 is the hermetic electric compressor described in the first embodiment.

  In the above configuration, since the vibration of the compressor is within a level where there is no practical problem, specifically, 40 μm or less, the excitation force to the refrigeration apparatus is small, and therefore the vibration is generated when the refrigeration apparatus resonates. To prevent abnormal noise. In addition, as described above, the components of the refrigeration apparatus are joined by piping by welding such as brazing, but if repeated stress due to large vibrations is applied to the brazed part, cracks due to fatigue may occur. There is. However, in this embodiment, since the vibration of the compressor is small, the stress amplitude of the repeated stress is small. As a result, the occurrence of cracks due to fatigue is suppressed, pipe breakage is less likely to occur, and a highly reliable refrigeration apparatus can be obtained. it can.

Sectional drawing of the hermetic electric compressor by Embodiment 1 of this invention Vibration characteristic diagram of hermetic electric compressor according to Embodiment 1 of the present invention The block diagram of the freezing apparatus by Embodiment 2 of this invention Cross-sectional view of a prior art hermetic electric compressor

Explanation of symbols

60 Inverter Device 61 Control Circuit 101 Sealed Container 102 Refrigerating Machine Oil 105 Electric Element 106 Compression Element 130 Piston 150 Suspension Spring 170 Compressor 180 Condenser 185 Dryer 187 Expander 189 Evaporator

Claims (6)

  A hydrocarbon refrigerant containing mainly a refrigerating machine oil, a compression element including a piston reciprocating in a compression chamber, and an electric element composed of a stator and a rotor for driving the compression element, and containing R600a as a main component. Is an inverter-driven reciprocating hermetic electric compressor driven at a plurality of operating frequencies including a rotational speed less than the commercial power supply frequency, wherein the piston has a reciprocating motion with respect to the outer diameter of the piston. The ratio is in the range of 1: 1 to 1.5: 1, the compression element is constructed substantially above the motorized element, and the compression element is interposed through the stator and below the stator. A hermetic electric compressor elastically supported from a container.   The hermetic electric compressor according to claim 1, wherein the hermetic electric compressor is driven at an operation frequency including at least 27 Hz or less.   The hermetic electric compressor according to claim 1 or 2, wherein a clearance between the compression chamber and the piston is in a range of 5 to 10 microns.   The hermetic electric compressor according to claim 1 or 2, wherein the refrigerating machine oil has a viscosity at a temperature of 40 degrees C within a range of 7 to 32 cSt.   A refrigerating apparatus comprising a compressor, a condenser, a dryer, an expander, and an evaporator, wherein the hermetic electric compressor according to any one of claims 1 to 4 is used as the compressor.   The refrigeration apparatus according to claim 5, wherein the compressor, the condenser, the dryer, the expander, and the evaporator are connected to each other by piping including brazing.

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