Patent Application
20100143167
The present invention relates to an electric compressor with an integral inverter, incorporated in a compressor with a motor drive circuit that includes the inverter, and specifically relates to an electric compressor with an integral inverter, which can minimize the charging resin amount to insulate and protect the motor drive circuit, and which can be reduced as a whole in weight and cost.
In a known structure of an electric compressor incorporated with a motor drive circuit including an inverter, etc., a motor drive circuit is coated by a resin mold material for insulation so as to be buried in the resin mold material. (e.g. patent document 1)
Further, in another known structure, a power semiconductor module located between a lid and a compressor housing (at the low pressure side in the housing) is coated and buried by pouring a insulating synthetic resin, etc. which has been heated to be fluidized. (e.g. patent document 2) In the structure described in patent document 2, a whole chamber containing electric parts such as a power semiconductor module, etc. is filled with a resin mold material.
Patent document 1: JP-2002-70743
Patent document 2: JP-4-80554
However, in the above-described conventional structure, because the motor drive circuit, etc. are completely buried by charging with resin substantially all over the chamber containing the motor drive circuit, etc., the amount of the charged resin or resin usage increases, so that it becomes difficult to reduce the cost and weight as a whole electric compressor. And especially for an electric compressor used in an air conditioning system for vehicles, it is needed to reduce the cost and weight as far as possible.
According to such problems and needs in conventional electric compressors, an object of the present invention is to provide an electric compressor with an integral inverter incorporated with a motor, in which the charged resin amount for the structure of the resin coated section in the motor drive circuit, etc. can be greatly reduced to make a whole compressor reduced in cost and weight.
To achieve the above-described object, an electric compressor with an integral inverter according to the present invention is a compressor which is incorporated with a motor and provided in a receiving space surrounded by a compressor housing with a motor drive circuit that includes the inverter, characterized in that at least some of electric parts including the motor drive circuit are coated at an assembly-completed state with a resin that is charged into the receiving space, and a shape of the charged resin is defined in the receiving space by a jig used at the time of resin charging and defining a space to be charged with the resin.
In other words, in the above-described conventional structure the resin is charged substantially all over the chamber receiving the motor drive circuit, etc., so that the resin is charged into a site which does not have to be coated, such as an inner wall of the receiving chamber. However, in a structure of the present invention, the jig defining the space to be charged with the resin is placed in the receiving space, during the charging with the resin into the receiving space. This jig is placed for partitioning the space to be charged with the resin at a site which needs to be coated with the resin, therefore does not basically define the space to be charged with the resin at a site which does not have to be coated with the resin. Therefore, as if an excess thickness in a conventional resin-charged form was removed at a site which does not have to be coated with the resin, the amount of the charged resin and resin usage can be surely reduced so as to reduce in weight and cost. On the other hand, at a site which has to be coated with the resin the resin can be surely coated at a predetermined thickness by charging with the resin into the space defined in a predetermined form to be charged with the resin.
As described above, the resin is charged at an assembly-completed state in the electric compressor with an integral inverter of the present invention. In a case that a lid member is provided to protect internal parts at the receiving space, the lid member may be dismounted to insert the jig, and the lid member may be mounted again after the completion of the resin charging and the jig dismounting. It can be performed extremely easily to dismount the jig after the resin-charging completion.
In the electric compressor with an integral inverter according to the present invention, such configuration can be employed that the jig defines the space to be charged with the resin for at least some of electric parts including the motor drive circuit and does not define the space to be charged with the resin for at least a part of the compressor housing which defines the receiving space. Because many sites which do not require the resin coating exist in at least a part of the compressor housing, specifically at an internal surface of the housing, which defines the receiving space. At such sites, the space to be charged with the resin should be neither defined nor coated with the resin. Reduction in weight and cost are hereby achieved still more efficiently.
Further, it is possible that the jig, defines the space to be charged with the resin for at least some of electric parts including the motor drive circuit, and does not define the space to be charged with the resin for at least the other parts. When plurality of the electric parts are provided, there sometimes exists an electric part which does not have either to be coated with the resin, or an electric part which does not have to be further coated with the resin at a site whose top section has been already coated by its own coverings. In such a case, the resin should not be coated at the sites which do not have to be coated, as far as possible. Whereby, further reduction of the amount of the resin usage and reduction in weight and cost can be achieved.
Further, the space to be charged with the resin may be defined so as to extend among at least some of electric parts. Whereby, specifically in a region where the electric parts are closely located to each other at small distances in the receiving space, the resin-charging can be performed integrally as straddling the electric parts. Therefore, each electric part can be fixed being kept in a predetermined form by the charged resin, without damaging electrical connection, etc.
In the electric compressor with an integral inverter according to the present invention, it is preferable that at least some of electric parts including the motor drive circuit are provided in the receiving space so as to enable heat exchange with refrigerant sucked as fluid to be compressed. In other words, it is preferred that the motor drive circuit is provided in or near the compressor housing located at the refrigerant suction path, so as to exchange the heat to the side of sucked refrigerant. Employing such a structure, the inverter, liable to become overheated can be properly cooled automatically, can maintain the designated performance of the motor drive circuit and can simplify the structure because a cooling means is not required to be provided separately.
In addition, it is preferable that the resin-charging is performed by charging with a liquid resin material into the space to be charged with the resin. Use of the liquid resin material can make the poured resin spread easily and quickly all over the appropriate region in the space to be charged with the resin, so as to simplify the work for the resin-charging. In a case that such a liquid resin material is used, the liquid resin material can be poured into the space to be charged with the resin so as to coat the essential target site with the resin, in a progression of the pouring process.
Further, it is also preferred in the present invention that at least some of electric parts including the motor drive circuit is charged with the resin under a residual heat condition after heating. In such a case, because the resin material is well fluidized responding to the residual heat, this technique can be adopted when a sufficient charged resin is required even in a minimal space in the space to be charged with the resin.
Further, in the present invention, it is possible that the jig itself is formed so as to be heatable, such that the jig has a heat source. In such a structure, especially in a case that the charged resin is a thermosetting resin, time to harden can be shortened by setting the jig temperature at the cure temperature or above.
It is preferred that the resin material used for the resin to be charged with is a thermosetting resin such as urethane or epoxy, etc. A thermosetting resin, after properly hardened, can maintain a sufficiently high heat resistance and durability even if the inverter, etc. becomes hot.
Further, a thickness of the charged resin (charged resin layer) is preferably 1 mm or more. The charged resin with 1 mm or more thickness can ensure a desired insulation performance and protection performance. Though the upper thickness is not limited, it is preferable that the thickness is set less than about 8 mm, especially less than about 6 mm, because too large thickness may cause the same problem as conventional complete buried forms.
The electric compressor with an integral inverter having the resin-charging structure according to the present invention is specifically suitable for a compressor used in an air conditioning system for vehicles which strongly requires the reduction in cost and weight as a whole compressor.
In the electric compressor with an integral inverter according to the present invention, because the resin is charged at an assembly-completed state into the space to be charged with the resin which is defined by the jig located in the receiving space, the resin coating can be performed only at the essential site with the minimum resin usage, so that the whole compressor can be reduced in cost and weight by the much less amount of the charged resin and the resin usage.
Hereinafter, desirable embodiments of the present invention will be explained referring to figures.
Receiving space 20 is formed being circumscribed by an extended section of compressor housing 12 (front housing) and motor drive circuit 21 is provided in receiving space 20. Specifically, motor drive circuit 21 is provided at the exterior side of partition wall 22 which is formed in compressor housing 12 separating from the side of the refrigerant suction path. Motor drive circuit 21 supplies electric power to motor 7 via lead wire 24, and via seal terminal 23 (output terminal of motor drive circuit 21) attached by penetrating through partition wall 22, and the side of refrigerant suction path and the side of a section placing motor drive circuit 21 are sealed at a section placing seal terminal 23. By providing motor drive circuit 21 at an exterior side of partition wall 22, at least some of electric parts including motor drive circuit 21 can exchange heat through partition wall 22 with suction refrigerant, so as to be cooled by suction refrigerant.
Motor drive circuit 21 includes IPM 25 (Intelligent Power Module) which can perform an inverter function and control circuit 26, and electric parts such as capacitor 27, etc. are provided with it separately or integrally. Motor drive circuit 21 is connected to an external power supply (not shown) through connector 28 as an input terminal. The opening side toward the outside of compressor housing 12 where electric parts including motor drive circuit 21 are mounted is covered in a state sealed with lid member 29, and these electric parts are protected by lid member 29.
Electric parts such as motor drive circuit 21 and capacitor 27, etc. is coated with a thermosetting resin, such as urethane or epoxy at a predetermined thickness (for example, 0.1 mm or more thickness), which is charged at an assembly-completed state. This resin is charged with as follows.
Jig 31 which has been preformed in a predetermined shape and used at the time of the resin charging is inserted into receiving space 20 in a condition where lid member 29 is dismounted, so that space to be charged with resin 32 is defined by jig 31 located at a predetermined position. Space to be charged with resin 32 is defined as having a predetermined void responding to a thickness of the charged resin, at the mounted electric parts, etc. For example, after resin 33 is charged (for example, poured with the liquid resin) from one side so as to fill in space to be charged with resin 32, surplus resin 34 is drained from the other side and after the resin hardened, the charged resin is defined in a shape which responds substantively to the shape of space to be charged with resin 32. Therefore, the amount of the charged resin and resin usage can be greatly reduced in comparison with a charging wholly into receiving space 20.
In addition, jig 31 does not define space to be charged with resin 32 at a site which does not need to be charged with the resin, for example, at least a part on an internal surface of compressor housing 12 defining receiving space 20, such as site 35. Therefore, the resin is not charged with at site 35, therefore the amount of the charged resin and resin usage can be much more reduced.
Further, it is possible for jig 31 to define space to be charged with resin 32 for at least some of electric parts including motor drive circuit 21, and for at least the other parts not define space to be charged with resin 32. For example, as shown in the FIGURE, a void (namely, space to be charged with resin 32) is formed between predetermined site 36 and a mounted electric part (electric part with a head section which does not need to be coated with the resin), so that jig 32 is located substantively in contact with the electric part. As described above, space to be charged with resin 32 is not defined locally at a site which does not need to be coated with the resin, so as to make the resin charging substantively unnecessary at the site, therefore the amount of the charged resin and resin usage can be much more reduced and the resin amount can be minimized. Such a reduction of the resin amount can achieve a reduction in weight and cost as a whole compressor.
Further, in a region where distances among the mounted electric parts, such as site 37 shown in the FIGURE, are short and therefore the electric parts are close to each other, space to be charged with resin 32 can be formed as extending among the electric parts and therefore the integral resin-charging straddling the electric parts can be performed. In this embodiment, because the electric parts close to each other are to be fixed to an integral charged resin section whose thickness is not large as is, each electric part can be kept in a desirable predetermined form without damage to an electric connection, etc.
After the resin-charging is completed, lid member 29 can be mounted. Further, the electric parts, etc. can be also charged with the resin under a residual heat condition after preheating as described above, or jig 31 itself can be controlled to be heated. Such configuration can make the resin material fluidized better responding to the residual heat, so as to charge with the resin sufficiently even into a minimal space in space to be charged with resin 32.
The coating structure according to the present invention can be applied to a general compressor with an integral inverter, and is specifically suitable to a compressor used in an air conditioning system for vehicles which strongly requires lightweight and cost reduction as a whole compressor.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-042160 | Feb 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/052341 | 2/13/2008 | WO | 00 | 1/11/2010 |
