A motor-driven compressor that suppresses the transmission of vibration and noise to the exterior, while obtaining heating performance that is sufficient for use in a heat pump. The motor-driven compressor includes a compressor mechanism, which compresses a refrigerant, and a motor mechanism, which actuates the compressor mechanism. The motor-driven compressor further includes an inner housing, which accommodates the compressor mechanism and the motor mechanism in a sealed state, and an outer housing, which accommodates the inner housing. The outer housing includes a mounting portion that can be mounted to another member. A first intermediate member is arranged between the inner housing and the outer housing. The first intermediate member includes anti-vibration and thermal insulation properties.

BACKGROUND OF THE INVENTION

The present invention relates to a motor-driven compressor.

Japanese Laid-Open Patent Publication No. 11-294365 discloses a motor-driven compressor of the prior art. The motor-driven compressor includes a compressor mechanism, which compresses a refrigerant, and a motor mechanism, which actuates the compressor mechanism. The motor-driven compressor includes an inner housing, which accommodates the compressor mechanism and the motor mechanism in a sealed state, and an outer housing, which accommodates the inner housing.

A spring, which supports the inner housing, is arranged in the outer housing of the motor-driven compressor. Thixotropic fluid is filled in a void formed between the outer housing and the inner housing. The outer housing includes a mounting portion that allows for mounting to another member.

The spring and thixotropic fluid function to suppress the transmission of vibration and noise from the compressor mechanism and motor mechanism to the exterior of the motor-driven compressor.

In this prior art motor-driven compressor, the heat of the high-temperature and high-pressure refrigerant compressed by the compressor mechanism is transmitted via the inner housing and the spring to the outer housing and released to the exterior or absorbed via the inner housing by the thixotropic fluid. Accordingly, there is a tendency for the heat of the refrigerant to be easily decreased. Thus, for example, when the motor-driven compressor is used in a heat pump, the heating performance of the heat pump becomes insufficient.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a motor-driven compressor that suppresses the transmission of vibration and noise to the exterior, while obtaining sufficient heating performance when used in a heat pump.

One aspect of the present invention is a motor-driven compressor including a compressor mechanism that compresses a refrigerant. A motor mechanism actuates the compressor mechanism. An inner housing accommodates the compressor mechanism and the motor mechanism in a sealed state. An outer housing accommodates the inner housing. The outer housing includes a mounting portion that can be mounted to another member. A first intermediate member is arranged between the inner housing and the outer housing. The first intermediate member includes anti-vibration and thermal insulation properties.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First and second embodiments of the present invention will now be described with reference to the drawings.

First Embodiment

Referring toFIG. 1, a motor-driven compressor1of the first embodiment is applied to an air conditioner installed in a vehicle to adjust the temperature of a passenger compartment. In addition to the motor-driven compressor1, the air conditioner includes a switch valve91, a passenger compartment exterior heat exchanger92, an expansion valve93, and a passenger compartment interior heat exchanger94.

As shown inFIG. 2, the motor-driven compressor1includes a compressor mechanism3, a motor mechanism5, an inner housing10, and an outer housing20. The inner housing10accommodates the compressor mechanism3and the motor mechanism5in a sealed state. The outer housing20accommodates the inner housing10.

In the present embodiment, the inner housing10includes a first housing11, which includes an open rear end (left end as viewed inFIG. 2), and a second housing12, which closes the rear end of the first housing11. The compressor mechanism3includes a fixed scroll3A, which is fixed to an inner circumferential surface11B of the first housing11, and a movable scroll3B, which is arranged to face the fixed scroll3A. The fixed scroll3A and movable scroll3B are engaged with each other and form a compression chamber3C. A drive shaft5A is accommodated in the first housing11. The drive shaft5A includes a distal portion (right side as viewed inFIG. 2) supported in a rotatable manner by a bearing5B, and a proximal portion (left side as viewed inFIG. 2) supported in a rotatable manner by a bearing5C.

The motor mechanism5is located closer to an end wall11D of the first housing11than the compressor mechanism3. A stator5D is fixed to the inner circumferential surface11B of the first housing11. A drive circuit (not shown) supplies the stator5D with three-phase current. A rotor5E is arranged in the stator5D. The rotor5E is fixed to the drive shaft5A. The rotor5E is rotated and driven by the current supplied to the stator5D. The drive shaft5A, stator5D, and rotor5E form the motor mechanism5.

Referring toFIGS. 1 and 2, when the motor mechanism5rotates and actuates the compressor mechanism3, the compressor mechanism3draws refrigerant into the inner housing10through a suction pipe95and compresses the refrigerant. Then, the compressor mechanism3discharges the compressed refrigerant from the inner housing10through a discharge pipe96.

Referring toFIG. 1, the switch valve91is connected to the motor-driven compressor1by the suction pipe95and the discharge pipe96. Further, the switch valve91is connected to the passenger compartment exterior heat exchanger92by a pipe97and the passenger compartment interior heat exchanger94by a pipe99. The expansion valve93is connected to the passenger compartment exterior heat exchanger92by a pipe98A and the passenger compartment interior heat exchanger94by a pipe98B.

The switch valve91, which is controlled by a control unit installed in the vehicle, can switch communication states of pipes. When the switch valve91communicates the discharge pipe96and pipe97, and communicates the suction pipe95and pipe99, the refrigerant discharged from the motor-driven compressor1through the discharge pipe96flows in direction D1as shown inFIG. 1. When the switch valve91communicates the discharge pipe96and pipe99, and communicates the suction pipe95and pipe97, the refrigerant discharged from the motor-driven compressor1through the discharge pipe96flows in direction D2as shown inFIG. 1.

The passenger compartment exterior heat exchanger92dissipates heat to or absorbs heat from the ambient air. The passenger compartment interior heat exchanger94dissipates heat to or absorbs heat from the air in the passenger compartment. The passenger compartment exterior heat exchanger92, the passenger compartment interior heat exchanger94, and the expansion valve93are known in the art and will not be illustrated or described in detail.

As shown inFIG. 2, the inner housing10includes a sealed cavity10A, which accommodates the compressor mechanism3and motor mechanism5in a sealed state. The inner housing10is generally cylindrical and elongated in the direction in which the compressor mechanism3and the motor mechanism5are arranged. The inner housing10may be formed from a single member or a plurality of members coupled to each other to define the sealed cavity10A. To obtain the durability required for the inner housing10to endure the vibration and heat, which are generated from the compressor mechanism3and motor mechanism5, and the high-temperature and high-pressure refrigerant, it is preferable that the inner housing10be formed from a metal, such as steel or aluminum.

The compressor mechanism3and the motor mechanism5are fixed in the sealed cavity10A by undergoing a known fastening process, such as shrinkage fitting, pressurized fitting, or bolt fastening. A fastening structure involving such a fastening process fixes the compressor mechanism3and the motor mechanism5with high rigidity. However, it is difficult to attenuate vibration and noise generated by the compressor mechanism3and motor mechanism5with such a structure. As a result, the vibration and noise of the compressor mechanism3and motor mechanism5are easily transmitted to the inner housing10. Heat is also easily transmitted from the compressor mechanism3and the motor mechanism5to the inner housing10.

A suction port15extends through the end wall11D of the first housing11. A suction coupling50, which serves as an outer pipe, is fixed to the suction port15. A refrigerant supply passage is formed in the sealed cavity10A between the suction port15and the compressor mechanism3.

A discharge chamber3D is defined between the first housing11and the second housing12. The second housing12includes an end wall12D through which a discharge port16extends. A discharge coupling60, which serves as an outer pipe, is fixed to the discharge port16.

The suction coupling50and discharge coupling60are known pipe couplings. The suction pipe95is coupled to the suction coupling50. The discharge pipe96is coupled to the discharge coupling60.

The outer housing20is generally cylindrical and elongated in the direction in which the compressor mechanism3and the motor mechanism5are arranged. The outer housing20, which accommodates the inner housing10, may be formed from a metal, such as steel or aluminum, a resin, or a fiber reinforced resin. The outer housing20includes two open ends in the longitudinal direction. The suction coupling50and the discharge coupling60respectively project outward from the two open ends. The suction coupling50and the discharge coupling60are not in contact with the outer housing20.

The outer housing20includes an outer wall surface20C. Block-shaped mounting portions29, which can be mounted to other members, are formed on the outer wall surface20C. The mounting portions29project outward in the radial direction of the outer housing20. An insertion hole29A extends through each mounting portion29parallel to the longitudinal direction of the outer housing20. A plurality of supports8project from a mounting object9, such as a frame or engine of the vehicle. The mounting portions29are engaged with the supports8. Bolts9A are fastened to the mounting portions29and supports8. This fixes the motor-driven compressor1to the mounting object9. The fastening structure of the mounting portions29, supports8, and bolts9A fix the outer housing20to the mounting object9with high rigidity. However, it is difficult to attenuate the vibration and noise transmitted from the outer housing20to the mounting object9.

In the present embodiment, first intermediate members31and32are arranged between the inner housing10and the outer housing20.

The first intermediate members31and32are formed from different materials. More specifically, the first intermediate members31have an anti-vibration property and is formed from an anti-vibration material, such as rubber, elastomer, resin, fiber reinforced resin, or silicon gel. In the present embodiment, the first intermediate members31are rubber annular bodies, or so-called O-rings. The first intermediate members31are arranged at the two longitudinal ends of the inner housing10and outer housing20in a compressed and deformed state between an inner wall surface20B of the outer housing20and an outer wall surface11C of the first housing11. Thus, the first intermediate members31support the inner housing10in the outer housing20.

The first intermediate member32has a thermal insulation property and is formed from a thermal insulation material, such as fiber mass of glass wool or the like, a foam material, cellulose fibers, or a vacuum insulation material. In the present embodiment, the first intermediate member32is a thick sheet of glass wool. The first intermediate member32, which is wound around the outer wall surface11C of the first housing11, fills the void between inner wall surface20B of the outer housing20and the outer wall surface11C of the first housing11. Thus, the first intermediate member32supports the inner housing10in the outer housing20in a supplemental manner. The first intermediate member32is sandwiched between the first intermediate members31and not exposed to the exterior from the two longitudinal ends of the inner housing10and outer housing20.

The air conditioner, to which the motor-driven compressor1of the first embodiment is applied, adjusts the temperature of the passenger compartment as described below.

Referring toFIG. 1, when cooling the passenger compartment, the switch valve91communicates the discharge pipe96and pipe97, and communicates the suction pipe95and pipe99. As a result, the high-temperature and high-pressure refrigerant compressed by the compressor mechanism3flows in direction D1. The refrigerant dissipates heat into the ambient air and liquefies at the passenger compartment exterior heat exchanger92. Then, the pressure of the refrigerant is decreased at the expansion valve93. Subsequently, the refrigerant absorbs heat from the air in the passenger compartment and vaporizes at the passenger compartment interior heat exchanger94. This cools the air in the passenger compartment. The refrigerant then returns to the motor-driven compressor1via the pipe99, the switch valve91, and the suction pipe95.

When heating the passenger compartment, the switch valve91communicates the discharge pipe96and pipe99, and communicates the suction pipe95and pipe97. As a result, the high-temperature and high-pressure refrigerant compressed by the compressor mechanism3flows in direction D2. The refrigerant dissipates heat into the air in the passenger compartment and liquefies at the passenger compartment interior heat exchanger94. This heats the air in the passenger compartment. Then, the pressure of the refrigerant is decreased at the expansion valve93. Subsequently, the refrigerant absorbs heat from the ambient air and vaporizes at the passenger compartment exterior heat exchanger92. The refrigerant then returns to the motor-driven compressor1via the pipe97, the switch valve91, and the suction pipe95.

In the motor-driven compressor1of the first embodiment, the compressor mechanism3and motor mechanism5are fixed to the inner housing10with high rigidity. Further, the mounting portions29, the supports8, and the bolts9A fix the outer housing20to the mounting object9with high rigidity. Thus, if the transmission of vibration and noise cannot be suppressed between the inner housing10and the outer housing20, the vibration and noise from the compressor mechanism3and motor mechanism5would be transmitted from the inner housing10and outer housing20to the mounting object9without being attenuated. This may adversely affect comfort in the environment of the passenger compartment. Further, if the transmission of heat between the inner housing10and outer housing20cannot be suppressed, the heat of the high-temperature and high-pressure refrigerant compressed by the compressor mechanism3would be dissipated to the exterior through the outer housing20.

In this regard, the motor-driven compressor1of the first embodiment includes the first intermediate members31and32, which have anti-vibration and thermal insulation properties and which are arranged between the inner housing10and the outer housing20. Since the first intermediate members31have an anti-vibration property, the transmission of vibration and noise, generated by the compressor mechanism3and motor mechanism5, from the inner housing10to the outer housing20and mounting object9is suppressed. The first intermediate members32, which are formed from glass wool, also suppress the transmission of vibration and noise from the inner housing10to the outer housing20.

Further, the first intermediate members32have a thermal insulation property. Thus, the heat of the high-temperature and high-pressure refrigerant compressed by the compressor mechanism3is not transmitted from the inner housing10to the first intermediate member32and the outer housing20. Further, the first intermediate members31, which are formed from rubber, also suppress the transmission of the heat of the refrigerant. Thus, the motor-driven compressor1prevents the heat from decreasing in the drawn in refrigerant and the discharged refrigerant. Accordingly, when the air conditioner functions as a heat pump and heats the passenger compartment, the temperature of the refrigerant flowing to the passenger compartment interior heat exchanger94can be increased. As a result, the passenger compartment interior heat exchanger94effectively dissipates heat to the air in the passenger compartment and exhibits sufficient heating performance.

The motor-driven compressor1of the first embodiment suppresses the transmission of vibration and noise to the exterior and exhibits sufficient heating performance when used in the heat pump.

The structure of the first embodiment also has the advantages described below.

The inner housing10accommodates the compressor mechanism3and the motor mechanism5in a sealed state. This allows the outer housing20to have a simple shape. Further, the first intermediate members31and32are arranged between the double-housing structure of the inner housing10and the outer housing20. Thus, the mounting portions29of the outer housing20and the structure that fastens the compressor mechanism3and motor mechanism5to the inner housing10do not have to be provided with an anti-vibration property. This simplifies the structure of such parts.

The suction coupling50and the discharge coupling60respectively coupled to the suction port15and the discharge port16are fixed to the inner housing10without contacting the outer housing20. Thus, the suction coupling50and discharge coupling60do not transmit vibration and noise from the compressor mechanism3and motor mechanism5to the outer housing20and its exterior. The suction coupling50and discharge coupling60also do not transmit the heat of the refrigerant to the outer housing20. This ensures that the motor-driven compressor1has the advantages of the present invention.

In the present example, the intermediate members arranged between the inner housing10and the outer housing20are the first intermediate members31, which have an anti-vibration property, and the first intermediate member32, which has a thermal insulation property. This increases the types of materials that can be used for the first intermediate members31and32and reduces the material cost in comparison with when the intermediate members of are each formed by a single member having both anti-vibration and thermal insulation properties.

The first intermediate member32, which is formed from a thermal insulation material, is arranged at the inner side between the inner housing10and the outer housing20, and the first intermediate members31, which are formed from an anti-vibration material, are arranged at the outer side between the inner housing10and the outer housing20. Thus, the first intermediate members31closes the void between the inner housing10and the outer housing20and protects the first intermediate member32located between the inner housing10and outer housing20. This prevents deterioration and loss of the material forming the first intermediate member32(e.g., glass wool) that may be caused by wind and rain.

The outer housing20has a simple cylindrical shape. This lowers the manufacturing cost. Further, the inner housing10can easily be accommodated in the outer housing20. This simplifies the assembling of the motor-driven compressor.

Second Embodiment

A motor-driven compressor2of a second embodiment uses a first intermediate member33in lieu of the first intermediate members31and32of the first embodiment. In addition, second intermediate members34are arranged between the inner housing10and suction coupling50and the inner housing10and discharge coupling60. Otherwise, the structure of the motor-driven compressor2is the same as that of the motor-driven compressor1of the first embodiment. Like or same reference numerals are given to those components that are the same as the corresponding components of the first embodiment.

The first intermediate member33is formed from a material having anti-vibration and thermal insulation properties. In the present example, the first intermediate member33is a cylinder having a thick wall of glass wool. The first intermediate member33fills the void between the inner wall surface20B of the outer housing20and the outer wall surface11C of the first housing11.

The second intermediate members34are formed from a material having either one of an anti-vibration property and a thermal insulation property. In the present example, the second intermediate members34are rubber annular bodies having an anti-vibration property.

The motor-driven compressor2of the second embodiment has the same advantages as the first embodiment.

The first intermediate member33is formed from a single member having anti-vibration and thermal insulation properties. Thus, in comparison to when using the first intermediate members31and32of the first embodiment, the number of components is reduced and the assembling procedures are simplified.

The second intermediate member34, which has an anti-vibration property, suppresses the transmission of vibration and noise from the compressor mechanism3and motor mechanism5between the inner housing10and suction coupling50, and between the inner housing10and discharge coupling60. The second intermediate members34suppress the transmission of heat from the refrigerant. Thus, in comparison with when the suction coupling50and discharge coupling60are directly fixed to the inner housing10, the transmission of refrigerant heat is suppressed from the inner housing10via the suction coupling50and discharge coupling60to the exterior. As a result, the motor-driven compressor2has the advantages of the present invention.

The outer housing20does not have to be cylindrical and include two open ends. The outer housing20may encase the entire inner housing10and include only one open end.

The fastening structure and shapes of the mounting portions29, the supports8, and the bolts9A are not limited to those of the above embodiments. Any structure can be employed as long as the mounting portions29can fix the motor-driven compressor1to the mounting object9.

In the first embodiment, the second intermediate member34of the second embodiment can be arranged between the suction port15and suction coupling50and/or between the discharge port16and the discharge coupling60. Further, as shown inFIG. 4, the motor-driven compressor1may include an intermediate member35, which integrates one of the first intermediate members31of the first embodiment with one of the second intermediate members34of the second embodiment. In this case, the part of the inner housing10that is not covered by the outer housing20is covered by the intermediate member35. The intermediate member35, which is formed from rubber, increases the covered region of the inner housing10. This improves the thermal insulation effect. As a result, dissipation of the refrigerant heat from the inner housing10to the exterior is further suppressed.

In the second embodiment, the second intermediate member34may be arranged only between the suction port15and suction coupling50or only between the discharge port16and discharge coupling60. Further, the intermediate member33may be formed integrally with the second intermediate member34.

The compressor mechanism3is not limited to a scroll type and may be of a reciprocating type, a vane type, or any other known compression type.