JP2012052497A - Electric compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric compressor which can collect moisture included in a circulating passage, and can restrain the characteristic deterioration in a built-in permanent magnet.SOLUTION: This electric compressor includes a housing 10 provided with a suction port 11 and a delivery port 12, a compression part 15 arranged in the housing 10, compressing a refrigerant sucked in from the suction port 11 and delivering it from the delivery port 12, and an electric motor 2 arranged in the housing 10 and rotating a rotary shaft 21 for driving the compression part 15, and the electric motor 2 includes a rotor 22 incorporated with the permanent magnet 3 and a stator 23 supported by the housing 10. The electric compressor includes a trap chamber 7 arranged in a lower outer part of the housing 10 and can store the moisture, and a communicating passage 75 for communicating the trap chamber 7 with the inside of the housing 10. The moisture of circulating inside the housing 10 together with the refrigerant and lubricating oil, can be collected to the trap chamber 7 via the communicating passage 75.

Description

  The present invention relates to an electric compressor used in a refrigeration cycle.

  An electric compressor used in a refrigeration cycle such as an in-vehicle air conditioner has an electric motor that drives a compression unit built in a housing that serves as a circulation path for refrigerant or the like. The electric motor has a built-in permanent magnet such as a ferrite magnet or a rare earth magnet. Therefore, the permanent magnet is exposed to an environment that can come into contact with the refrigerant and the lubricating oil circulating in the circulation path of the refrigeration cycle.

Further, the circulation path of the refrigeration cycle may be in a state of containing moisture due to, for example, deterioration of the refrigerant or lubricating oil over time or the influence of the usage environment. In the presence of moisture, acid may be generated from the refrigerant or lubricating oil. When moisture or acid circulates together with a refrigerant or the like, the permanent magnet comes into contact with moisture or acid and is likely to deteriorate due to reaction with these.
In order to cope with such a problem, it has been proposed to form a protective film for improving the corrosion resistance of the permanent magnet on the surface of the permanent magnet built in the electric motor of the electric compressor (see Patent Document 1). .

JP 2009-225636 A

  The formation of the protective film can enhance the effect of preventing the permanent magnet from being deteriorated as compared with the case where the protective film is not formed. However, when the protective film is scratched or the like, the deterioration preventing effect by the protective film is reduced. Therefore, regardless of the presence or absence of a protective film, the moisture contained in the circulation path that causes deterioration of the permanent magnet is collected as much as possible, and the contact opportunity between the moisture or the acid generated due to the moisture and the permanent magnet It is considered that an effective measure is to reduce

  The present invention has been made in view of such problems, and is intended to provide an electric compressor that can recover moisture contained in a circulation path and can suppress deterioration of characteristics of a built-in permanent magnet. To do.

The present invention includes a housing provided with a suction port and a discharge port, a compression portion that is disposed in the housing and compresses refrigerant sucked from the suction port and discharges the refrigerant from the discharge port, and is disposed in the housing. In an electric compressor comprising: an electric motor that rotates a rotating shaft that drives a compression unit, and the electric motor includes a rotor having a built-in permanent magnet and a stator supported by the housing.
A trap chamber capable of containing moisture disposed outside the housing, and a communication path for communicating the trap chamber with the interior of the housing;
The electric compressor is characterized in that the water circulating with the refrigerant and the lubricating oil in the housing can be collected in the trap chamber through the communication path (Claim 1).

  When water is contained in the circulation path of the refrigeration cycle including the electric compressor, when the operation of the electric compressor is stopped, it tends to be easily collected as free water at the bottom of the housing due to the specific gravity. As described above, the electric compressor of the present invention has the trap chamber outside the housing, and the trap chamber communicates with the inside of the housing through the communication passage. Therefore, the free water present in the housing of the electric compressor is collected in the trap chamber outside the housing through the communication path whenever it accumulates at the bottom of the housing of the electric compressor. This trap chamber is provided outside the housing and is out of the circulation path of the refrigerant and the like during operation of the electric compressor. Therefore, the water once collected in the trap chamber is prevented from returning into the housing. Therefore, even when the circulation path contains moisture, every time the electric compressor is repeatedly operated and stopped, the moisture that has become free water is collected in the trap chamber, and the permanent magnet caused by the moisture is removed. Characteristic deterioration and the like can be suppressed.

FIG. 3 is an explanatory diagram illustrating a configuration of an electric compressor in the first embodiment. Explanatory drawing which shows the structure of the vehicle-mounted air conditioner in Example 1. FIG. Explanatory drawing which shows the structure of the electric compressor in Example 2. FIG. Explanatory drawing which shows the structure of the electric compressor in Example 3. FIG. FIG. 10 is a longitudinally enlarged explanatory view of a communication path in the third embodiment. The horizontal expansion explanatory drawing (B arrow view of FIG. 5) of the communicating path in Example 3. FIG.

In the electric compressor, it is preferable that an opening area of the communication path is 0.75 to 650 mm ² . It is effective to suppress the opening area of the communication passage so that it is not larger than a level that is not easily affected by the surface tension of free water and does not disturb the circulation state of the circulation path. . For this reason, the opening area of the said range is preferable. When the opening area is less than 0.75 mm ² , it may be difficult to smoothly guide the free water to the trap chamber by closing the opening due to the influence of the surface tension of the free water. On the other hand, when the opening area exceeds 650 mm ² , the circulation path of the refrigerant or the like is affected, and there is a possibility that the water collected in the trap chamber returns to the circulation path again. Therefore, when the communicating path has a circular cross section, the opening diameter is preferably 1 mmφ to 50 mmφ that satisfies the range of the opening area.

  The communication path is preferably provided with a backflow suppression mechanism for suppressing the water flowing into the trap chamber from flowing back into the housing. As the backflow suppression mechanism, a structure in which one or a plurality of return plates inclined so that the tip approaches the trap chamber can be employed on the inner peripheral surface of the communication path. In this case, it is possible to further enhance the effect of suppressing the water collected in the trap chamber from flowing back into the housing.

  The communication path is preferably inclined so that a central axis direction from the trap chamber toward the housing intersects at an acute angle with respect to a circulation direction in the circulation path. Also in this case, the effect of suppressing the water collected in the trap chamber from flowing back into the housing can be further enhanced.

  Moreover, it is preferable that the trap chamber is detachably disposed on the housing. In this case, the moisture collected in the trap chamber can be discarded by removing the trap chamber using an opportunity to perform periodic inspection. Various known connection mechanisms can be adopted as the detachable mechanism.

  Moreover, it is preferable that an in-machine environment improving agent including at least one of an adsorbent that adsorbs moisture and a neutralizing agent that neutralizes acid is disposed in the trap chamber. Since the internal environment improving agent is disposed in the trap chamber, the moisture introduced into the trap chamber can be adsorbed by the adsorbent, or the acid introduced into the trap can be neutralized by the neutralizer. It is possible to more strongly suppress the deterioration of the characteristics of the permanent magnet caused by acid and acid.

  The adsorbent is preferably composed of at least one of zeolite, activated carbon, alumina, and silica gel. These adsorbents are excellent in moisture adsorption performance per unit volume, and are effective for disposing in a limited space in the rotor. In addition, these adsorbents may be generally called desiccants.

  The neutralizing agent preferably comprises at least one of calcium hydroxide, magnesium hydroxide, calcium carbonate and sodium carbonate. These are preferable because they are solid and exist stably for a long period of time.

  The permanent magnet may be a rare earth magnet. As a permanent magnet for an electric compressor, a ferrite magnet or the like can be applied, but a rare earth magnet is more suitable from the viewpoint of magnetic characteristics. On the other hand, rare earth magnets tend to corrode more easily than ferrite magnets. Therefore, it is effective to quickly collect moisture that causes corrosion in the trap chamber provided in the electric compressor itself.

  Moreover, it is preferable that the said electric compressor is for vehicle-mounted air conditioners provided with the nonmetallic piping in the circulation path (Claim 8). The on-vehicle air conditioner includes a condenser, an expansion valve, an evaporator, and the like in addition to the compressor, and has a configuration in which refrigerant and lubricating oil are enclosed in a circulation path that connects these. In some cases, non-metallic pipes such as resin pipes may be employed for some of the pipes constituting the circulation path in order to provide flexibility or improve vibration damping. The resin here is a resin in a broad sense, and is a concept including a so-called natural resin, synthetic resin, natural rubber, synthetic rubber and the like. Non-metallic pipes such as resin pipes often have a characteristic of allowing moisture to permeate, although very little. Therefore, for example, if it is used for many years in a hot and humid environment, moisture may enter the circulation path from the air through non-metallic pipes such as resin pipes. In addition, there may be a case where the refrigerant or lubricating oil changes in quality due to the moisture that has entered the circulation path, and an acid or the like is generated. Therefore, in the vehicle air conditioner, it is effective to quickly collect the water accumulated in the housing in the trap chamber as described above.

The electric compressor has a molecular formula: C ₃ H _m F _n (where m is an integer of 1 to 5, n is an integer of 1 to 5, and m + n = 6). It is preferably used in a refrigeration cycle in which a refrigerant having one bond or a mixed refrigerant containing the refrigerant is circulated.
As a refrigerant used in the refrigeration cycle, a refrigerant that has less influence on the destruction of the ozone layer than a refrigerant called a conventional chlorofluorocarbon has been used. Such a new type of refrigerant has a molecular formula: C ₃ H _m F _n (such as CF ₃ —CF═CH ₂ (2,3,3,3-tetrafluoro-1-propene). However, m is an integer of 1 to 5, n is an integer of 1 to 5, and m + n = 6), and a refrigerant having one double bond in the molecular structure has attracted attention (hereinafter, “ HFO1234yf type refrigerant ").

  Since the HFO1234yf type refrigerant includes a double bond as described above, it has a characteristic that it is relatively easily decomposed in the presence of water. Therefore, when water is mixed in the refrigerant circuit for some reason during the manufacturing process or use in the market, there is a possibility that the refrigerant is decomposed and hydrofluoric acid (HF) is generated from F constituting the refrigerant. So-called acids such as hydrofluoric acid cause the permanent magnets to corrode relatively quickly. Therefore, in the refrigeration cycle using the HFO1234yf type refrigerant, as described above, it is effective to quickly collect the water accumulated in the housing in the trap chamber.

  The electric compressor is also effective when a lubricating oil containing at least one of polyol ester (POE), polyvinyl ether (PVE), and polyalkylene glycol (PAG) is contained in the housing. 10). Even when these lubricating oils are included, it is not preferable that water, acid, or the like enter the refrigerant circulation path. For example, a polyol ester is hydrolyzed in the presence of moisture to generate an organic carboxylic acid. The organic carboxylic acid can cause the permanent magnet to corrode similarly to the hydrofluoric acid described above. Therefore, also in this case, it is effective to quickly collect the water accumulated in the housing in the trap chamber.

Example 1
An electric compressor according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the electric compressor 1 of this example includes a housing 10 provided with a suction port 11 and a discharge port 12, and compresses refrigerant that is disposed in the housing 10 and sucks from the suction port 11 to discharge the port 12. And the electric motor 2 that rotates the rotating shaft 21 that is disposed in the housing 10 and drives the compression unit 15.

  The compression unit 15 includes a fixed scroll 13 fixed in the housing 10 and a movable scroll 14 disposed to face the fixed scroll 13. A variable volume compression chamber 150 for compressing the refrigerant is formed between the fixed scroll 13 and the movable scroll 14. The movable scroll 14 is connected to the eccentric pin 210 of the rotary shaft 21 via the bearing 216 and the eccentric bush 215, and swings in accordance with the rotation of the rotary shaft 21 to change the volume of the compression chamber 150. Has been.

The rotating shaft 21 is fixed to the center hole 221 of the rotor 22 constituting the electric motor 2, and both ends protruding from the center hole 221 to both sides are fixed to the housing 10 via bearing portions 41, 42 so as to be rotatable. .
As shown in FIG. 1, the electric motor 2 includes a rotor 22 fixed around the rotating shaft 21, and a stator 23 disposed on the outer peripheral side of the rotor 22 and supported by the housing 10. The stator 23 is provided with a coil 235, and the rotor 22 having the permanent magnet 3 built therein is rotated by energizing the coil 235.

  As shown in FIG. 1, the rotor 22 is formed in a cylindrical shape by laminating a plurality of electromagnetic steel plates, and has a plurality of magnet arrangement holes 225 penetrating in the axial direction. In each case, a permanent magnet 3 is inserted and arranged. As the permanent magnet 3, a known neodymium magnet (rare earth magnet) mainly composed of neodymium (Nd), iron (Fe), and boron (B) was employed.

Furthermore, the electric compressor 1 of this example is provided with a trap chamber 7 that is disposed outside the housing 10 and can store moisture, and a communication passage 75 that allows the trap chamber 7 to communicate with the inside of the housing 10. It becomes. The communication path 75 has a circular cross section, has an inner diameter of 20 mmφ (opening area 314 mm ² ), and is arranged so that the direction of the central axis thereof is in the vertical direction. The internal volume of the trap chamber 7 is sufficiently large so that all of the free water 8 expected to be generated can be recovered.

In this example, as shown in FIG. 2, the electric compressor 1 having the above configuration is used as a compressor of the in-vehicle air conditioner 5.
As shown in the figure, the in-vehicle air conditioner 5 includes a condenser 51, a receiver 52, an expansion valve 53, and an evaporator 54 that are sequentially communicated by a circulation path 55 from the discharge port 12 side of the electric compressor 1. . The expansion valve 53 is configured such that the valve opening degree of the expansion valve 53 is adjusted by the control unit 57 in accordance with the temperature of the refrigerant measured by the temperature sensor 56 disposed on the downstream side of the evaporator 54.

The receiver 52 functions to separate the refrigerant from gas and liquid to send only the liquid refrigerant to the expansion valve, and removes moisture contained in the refrigerant by a built-in receiver adsorbent (not shown). It is configured.
In addition, CF ₃ —CF═CH ₂ (2,3,3,3-tetrafluoro-1-propene) is sealed as a refrigerant in the circulation path 55, that is, the electric compressor 1, and the lubricating oil As a result, a polyol ester is encapsulated. In addition, a resin pipe that is a non-metallic pipe is adopted as a part of the pipe constituting the circulation path 55.

  When the vehicle-mounted air conditioner 5 having such a configuration is operated for a long period of time, moisture penetrates into the circulation path 55 through the resin piping constituting the circulation path 55. When water is contained in the circulation path 55 of the refrigeration cycle including the electric compressor 1, when the operation of the electric compressor 1 is stopped, it tends to be easily collected as free water at the bottom of the housing 10.

  Here, as described above, the electric compressor 1 includes the trap chamber 7 that is disposed outside the housing 10 and can store moisture, and the communication passage 75 that allows the trap chamber 7 to communicate with the inside of the housing 10. Is provided. Therefore, the free water 8 present in the housing of the electric compressor 1 is collected in the trap chamber 7 outside the housing 10 through the communication path 75 whenever it accumulates at the bottom of the housing 10 of the electric compressor 1.

  The trap chamber 7 is provided outside the housing 10 and is out of the circulation path 55 of the refrigerant or the like when the electric compressor 1 is operated. Therefore, the water once collected in the trap chamber 7 is prevented from returning into the housing 10. Therefore, even when the circulation path 55 is in a state where moisture is contained, every time the electric compressor 1 is repeatedly operated and stopped, the moisture that has become the free water 8 is collected in the trap chamber 7 and is permanently caused by the moisture. The characteristic deterioration of the magnet 3 can be suppressed.

(Example 2)
In this example, as shown in FIG. 3, the electric compressor 1 of the first embodiment is used as a basic configuration, and the form of the communication path connecting the housing 10 and the trap chamber 7 is changed.
That is, as shown in the figure, the communication path 76 of this example is such that the angle α at which the direction of the central axis C from the trap chamber 7 toward the housing 10 intersects the circulation direction A in the circulation path is an acute angle. The axis C is inclined.
Others are the same as in the first embodiment.

In the case of this example, since the communication path 76 is inclined as described above, the free air collected in the trap chamber 7 is affected by the circulation of refrigerant or the like when the electric compressor 1 is operating. The effect of suppressing the water 8 from flowing back into the housing 10 or the refrigerant or the like from flowing into the trap chamber 7 can be further enhanced.
In other respects, the same effects as those of the first embodiment can be obtained.

(Example 3)
As shown in FIGS. 4 and 5, this example is also an example in which the electric compressor 1 of the first embodiment is used as a basic configuration and the form of the communication path connecting the housing 10 and the trap chamber 7 is changed.
That is, as shown in the figure, the communication passage 77 of this example is provided with three return plates 79 as a backflow suppressing mechanism for suppressing the water flowing into the trap chamber 7 from flowing back into the housing 10. It has been. As shown in FIG. 5, the return plate 79 is fixed to the inner peripheral surface of the communication passage 77, and is inclined so that the tip 791 approaches the trap chamber 7. Further, when viewed from the central axis direction of the communication path 77, as shown in FIG. 6, a part of a circular cross section of the communication path is cut out by a linear tip 791.

In this case, when recovering the free water 8, the surface of the return plate 79 disposed obliquely can be sequentially transmitted to the trap chamber 7. On the other hand, the free water 8 once collected in the trap chamber 7 is pushed back by the return plate 79 even if it tries to flow backward through the communication passage 77, and the effect of suppressing the flow backward into the housing 10 can be further enhanced. it can.
In other respects, the same effects as those of the first embodiment can be obtained.

  In addition, in each trap chamber 7 shown in the first to third embodiments, an in-machine environment improving agent including at least one of an adsorbent that adsorbs moisture and a neutralizer that neutralizes acid can be disposed. . In this case, the moisture introduced into the trap chamber 7 can be adsorbed by the adsorbent, or the acid introduced into the trap can be neutralized by the neutralizing agent. Can be suppressed more strongly.

DESCRIPTION OF SYMBOLS 1 Electric compressor 10 Housing 11 Suction port 12 Discharge port 15 Compression part 2 Electric motor 21 Rotating shaft 22 Rotor 23 Stator 225 Magnet arrangement | positioning hole 3 Permanent magnet 7 Trap chamber 75, 76, 77 Communication path

Claims (10)

A housing provided with a suction port and a discharge port; a compression unit disposed in the housing for compressing a refrigerant sucked from the suction port and discharging the refrigerant from the discharge port; and a drive unit disposed in the housing for driving the compression unit An electric compressor that rotates a rotating shaft, and the electric motor includes a rotor having a built-in permanent magnet and a stator supported by the housing.
A trap chamber capable of containing moisture disposed outside the housing, and a communication path for communicating the trap chamber with the interior of the housing;
An electric compressor characterized in that water circulated in the housing together with refrigerant and lubricating oil can be collected in the trap chamber through the communication path. In claim 1, the opening area of the communication path, an electric compressor which is a 0.75~650mm ^2.   3. The electric compressor according to claim 1, wherein the communication passage is provided with a backflow suppression mechanism for suppressing the water flowing into the trap chamber from flowing back into the housing.   In any 1 paragraph of Claims 1-3, The above-mentioned communicating path inclines so that the central axis direction which goes to the above-mentioned housing from the above-mentioned trap room intersects at an acute angle with respect to the circulation direction in the above-mentioned circulation path. A featured electric compressor.   5. The electric compressor according to claim 1, wherein the trap chamber is detachably disposed on the housing. 6.   In any 1 item | term of Claims 1-5, the in-machine environment improving agent containing at least one of the adsorption agent which adsorb | sucks a water | moisture content, and the neutralizing agent which neutralizes an acid is arrange | positioned in the said trap chamber. A featured electric compressor.   The electric compressor according to claim 1, wherein the permanent magnet is a rare earth magnet.   The electric compressor according to any one of claims 1 to 7, wherein the electric compressor is for an on-vehicle air conditioner having a non-metallic pipe in a circulation path. 9. The electric compressor according to claim 1, wherein the electric compressor has a molecular formula: C ₃ H _m F _n (where m is an integer of 1 to 5, n is an integer of 1 to 5, and m + n = 6 And an electric compressor characterized by being used in a refrigeration cycle for circulating a refrigerant having one double bond in the molecular structure or a mixed refrigerant containing the refrigerant.   10. The electric compressor according to claim 1, wherein the electric compressor includes a lubricating oil containing at least one of polyol ester (POE), polyvinyl ether (PVE), and polyalkylene glycol (PAG) in the housing. The electric compressor characterized by including in.

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