Mounting structure and motor compressor having the same

A mounting structure has a base member, a mounted member and a plurality of C-shaped retainer rings. The base member has an opening. The mounted member is fitted to the opening. The plurality of C-shaped retainer rings is fitted to the base member for preventing the mounted member from moving away from the base member.

BACKGROUND OF THE INVENTION

The present invention relates to a mounting structure and a motor compressor having the same.

A motor compressor driven by an electric motor is required to ensure the airtightness of its housing while allowing power from an external source to be supplied to a motor chamber of the compressor. For this reason, an airtight terminal to be mounted to the housing is generally known. One example of the airtight terminal is disclosed in Japanese Patent Application Publication No. 2004-190547, in which the airtight terminal is securely mounted to the housing by screw member.

However, a mounting structure using a conventional fixing manner has a problem in that a thicker base is required around a position to mount the airtight terminal. This is because screw members are used for fixing the airtight terminal and, therefore, the housing needs a sufficient thickness for screw holes. This also produces a problem in that the position of the airtight terminal is restricted.

In the conventional structure as shown in FIG. 1 of the above-cited Publication No. 2004-190547, the airtight terminal must be located remote from the middle of the housing. It is noted that the middle of the housing refers to the position of a line of intersection between the mounting plane for the airtight terminal that extends normal to the axis of the screw member and a plane that is normal to the mounting plane and includes the axis of drive shaft for the motor compressor.

The present invention is directed to a mounting structure that permits the housing to be made thinner than heretofore around the mounting position of the airtight terminal and also to a motor compressor having the same.

SUMMARY OF THE INVENTION

In accordance with the present invention, a mounting structure has a base member, a mounted member and a plurality of C-shaped retainer rings. The base member has an opening. The mounted member is fitted to the opening. The plurality of C-shaped retainer rings is fitted to the base member for preventing the mounted member from moving away from the base member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe a first preferred embodiment of a mounting structure used for a motor compressor10according to the present invention with reference toFIGS. 1 through 5.

The motor compressor10has a first housing190and a second housing25, which are fastened together by a plurality of bolts16. The first housing190is formed in a cylindrical shape, including a cylindrical portion190fand an end190g. The end190gis formed with a cylindrical boss190hfor holding therein a ball bearing22f. The motor compressor10includes a fixed scroll member11and a movable scroll member12which cooperate to form therebetween compression chambers13. The fixed scroll member11has a disc-shaped fixed base plate11a, a fixed scroll wall11bextending from the fixed base plate11aand an outermost fixed scroll wall11c. The fixed base plate11ahas a discharge port47at the center thereof. In the motor compressor10, the fixed scroll member11, the movable scroll member12and the compression chambers13cooperate to form a compression mechanism. The movable scroll member12includes a disc-shaped movable base plate12aand a movable scroll wall12bextending from the movable base plate12a. The movable base plate12ais formed with a cylindrical boss12cat the center on the back surface thereof for holding a ball bearing17.

The motor compressor10further includes a crank mechanism19for orbiting the movable scroll member12and pins20for preventing self-rotation of the movable scroll member12. The pins20are securely mounted to a shaft support member15and loosely fitted in respective annular recesses12dof the movable scroll member12. The crank mechanism19includes the boss12c, a crank pin22aof the drive shaft22and the ball bearing17fitted around the crank pin22athrough a bushing18for supporting the movable scroll member12.

An airtight terminal101is mounted to the first housing190. It is noted that the airtight terminal101and its surrounding are shown inFIG. 1in cross-section taken along a plane that is different from that for the other parts of the compressor. The airtight terminal101has conductive members extending through the first housing190while maintaining airtightness between the motor chamber27and the outside of the compressor10. The details of the airtight terminal101will be described later.

The motor compressor10has a driving motor26, which is a three-phase synchronous motor for driving the compression mechanism, including the drive shaft22extending through the center of the driving motor26, a rotor28fitted on the drive shaft22and a stator30located outside the rotor28and having a coil29wound therearound. Operation or rotational speed of the driving motor26is controlled by an inverter (not shown) in a manner well known in the art.

One end of the drive shaft22adjacent to the crank mechanism19is supported by the shaft support member15through a ball bearing22e, while the other end is supported by the boss190hof the first housing190through a ball bearing22f. A seal22gis provided on the rear side of the ball bearing22eto seal the gap between the drive shaft22and the shaft support member15. InFIG. 1, the right side which is adjacent to the second housing25is defined as the front side of the compressor10, while the left side which is adjacent to the end190gof the first housing190is defined as the rear side of the compressor10.

A space defined by the first housing190and the second housing25is the chamber of the motor compressor10, and refrigerant flows through this chamber. In the chamber of the motor compressor10, a space defined by the first housing190and the shaft support member15is a motor chamber27, and a space defined by the first housing190, the second housing25and the shaft support member15is a crank chamber21. The motor chamber27and the crank chamber21are in communication with each other through a suction passage (not shown).

A discharge chamber32is defined by the fixed scroll member11and the second housing25on the side opposite to the compression chambers13with the discharge port47disposed therebetween. A reed valve34and a retainer36are provided in the discharge chamber32for preventing backflow of refrigerant, that is, flow of refrigerant from the discharge chamber32toward the discharge port47. The discharge chamber32has an outlet32athat is in communication with the outside. This outlet32aestablishes fluid communication between the inside and outside of the motor compressor10.

In the above motor compressor10, refrigerant flows through a suction port (not shown) into the motor chamber27, from which the refrigerant then flows into the crank chamber21and the compression chamber13that is in communication with the crank chamber21through a suction passage (not shown). In the compression chambers13, refrigerant is compressed by orbital movement of the movable scroll member12in accordance with rotation of the drive shaft22, flows into the discharge chamber32through the discharge port47and is then discharged through the outlet32a.

For the sake of convenience,FIG. 4shows only the airtight terminal101, the first housing190and the stator30. The airtight terminal101is located at a distance D from the center of the first housing190, that is, an imaginary plane which is normal to the sheet ofFIG. 4and including the centerline C inFIG. 4. InFIG. 4, the distance D is shorter than a distance W between the centerline C and the end190xof the first housing190.

Referring toFIGS. 2 and 3, the airtight terminal101, which corresponds to a mounted member in this embodiment, is mounted to the first housing190, which corresponds to a base member in this embodiment. The airtight terminal101sealingly separates the inside of the first housing190from the outside of the compressor10. The airtight terminal101includes an electrically insulative support member102. The support member102is made of a plate which is formed in a shape of a track, i.e. a shape consisting of two semicircles connected by parallel lines tangent to their endpoints, and has three holes111a,112a,113athrough which three conductive members111,112,113extend, respectively. Of these holes111a,112a,113a, the hole112ais located at the middle of the two parallel lines of the support member102, and the holes111aand113aare located at the center of the respective semi-circles thereof, respectively. These holes111a,112a,113aare aligned on the same line.

The conductive members111,112,113are supported by extending through these three holes111a,112a,113a. Each of the conductive members111,112,113has a solid cylindrical shape with the same diameter as the holes111a,112a,113a. The conductive members111,112,113are fitted into the holes111a,112a,113aand fixed at the longitudinally middle portions thereof. Each of the conductive members111,112,113corresponds to each one of the three-phase lines of the driving motor26and is electrically connected to the respective coil.

Adhesive designated by121,122,123is applied to portions where the conductive members111,112,113are supported by the support member102and their vicinities around the conductive members111,112,113. Thus, the support member102and the conductive members111,112,113are bonded together securely. The adhesive121,122,123is typically made of resin, but other adhesives or fixing materials, such as rubber and glass, are usable as far as they fix the conductive members111,112,113to the support member102.

The first housing190has an opening190bfor mounting the airtight terminal101. The first housing190includes a large-diameter wall surface190cand a small-diameter wall surface190d, which surround the opening190b, and a step190aformed at the boundary between the surfaces190c,190d. The area of the opening190bat the large-diameter wall surface190cformed on the outer side of the first housing190is larger than that of the small-diameter wall surface190cformed on the inner side of the first housing190. The airtight terminal101will be mounted to the first housing190such that the support member102is fitted in the opening190bwith the inner surface102aof the support member102set in contact with the step190a. As shown inFIG. 3, the cylindrical conductive members111,112,113extend axially in the same direction as the thickness direction of the first housing190.

An O-ring groove141a, or a rectangular groove that opens toward the support member102, is formed in the surface at the step190abetween the large-diameter and small-diameter wall surfaces190cand190dof the first housing190for receiving therein an O-ring141. The support member102is set in the opening190bof the first housing190with the inner surface102aof the support member102pressed against the O-ring141thereby to airtightly close the opening190bof the first housing190. Thus, a seal structure is formed between the first housing190and the airtight terminal101for sealingly closing the opening190bof the first housing190of the motor compressor10. The airtight terminal101is in contact with the O-ring141of the seal structure on the side adjacent to the axis of the motor compressor10.

C-shaped circlips131,132, which correspond to retainer rings in this embodiment, are used for securing the airtight terminal101in place to the first housing190. The circlip131has a known structure having a C-shaped body131band two annuluses131cprovided at the opposite terminating ends of the body131b. Engaging the tip ends of a fitting tool, such as a pair of pliers, with the annulus131cand then applying a force appropriately, the shape of the body131bmay be deformed inwardly. The circlip131thus inwardly deformed is inserted in place in the opening190b. The circlip132shown on the right side ofFIGS. 2and3has the same shape as the circlip131, having a C-shaped body132band two annuluses132c.

Circlip grooves131a,132a, which correspond to rectangular retainer ring grooves in this embodiment, are formed in the large-diameter wall surface190cof the first housing190for receiving therein the circlips131,132, respectively. The circlips131,132are supported by the circlip grooves131a,132a, respectively and are in contact with the outer surface102bof the support member102for preventing outward movement of the support member102. Thus, the airtight terminal101is prevented from moving away from the first housing190, that is, the step190a. The circlips131,132are in contact with the airtight terminal101at single flat contact surfaces131d,132d, respectively.

As shown inFIG. 2, two circlips131,132are disposed in a mirror-image relation or with a reversal of right and left. The direction of the circlip131is defined as a direction in which the middle point between the annuluses131cis located with respect to the center of an imaginary circle of the body131b. The direction of the circlip131is indicated by the arrow A inFIG. 2, as seen from the center of the body131btoward the center of gravity of the circlip131. The direction of the circlip132is also defined in the same way. The circlips131,132are located at positions that do not overlap each other as seen from each end surface thereof. Thus, the side wall surrounding the opening190bhas circlip grooves131a,132aformed along the side wall and a step190aextending toward the center of the opening190bbelow the circlip grooves131a,132a.

InFIG. 3, the O-ring141which is in contact with the support member102urges the support member102outward. Outward movement of the support member102is prevented by the circlips131,132, so that the O-ring141is pressed against the inner surface102aof the support member102. Meanwhile, the O-ring141is also pressed against the first housing190, so that the first housing190adjacent to the airtight terminal101is sealingly closed. The adhesive121,122,123which fixes the support member102to the conductive members111,112,113seals the gap between the support member102and the conductive members111,112,113to ensure complete sealing of the airtight terminal101. Thus, the airtight terminal101is located on the step190a, and a plurality of the circlips131,132is provided on the upper surface of the airtight terminal101, that is, the outer surface102bof the support member102so as to be fitted in the circlip grooves131a,132a, respectively. This structure restricts outward movement of the airtight terminal101.

As described above, the airtight terminal101according to the first preferred embodiment is fixed to the first housing190by means of the circlips131,132, thus dispensing with a screw member for fixing the airtight terminal101. This eliminates the need of providing a housing that is thick enough to form therethrough screwing holes, but permits the use of a housing with a reduced thickness around the airtight terminal101.

Therefore, the compressor housing may be designed with a higher degree of freedom regarding the position where the airtight terminal is mounted to the housing. In the example shown in FIG. 1 of Japanese Patent Application Publication No. 2004-190547, the airtight terminal must be located at an end of the housing or a part thereof adjacent to the end having a sufficient thickness. Namely, the airtight terminal may only be mounted at a position of the housing having a larger dimension for the distance D ofFIG. 4. According to this embodiment, on the other hand, the position of the airtight terminal101is not limited to the end190xof the first housing190, but the airtight terminal101may be provided at a position closer to the centerline C as shown inFIG. 4, that is, a position where the distance D is relatively short.

Thus, the airtight terminal101of the above-described first preferred embodiment helps to reduce the wall thickness for mounting structure of the airtight terminal101and also improves the degree of freedom of position for mounting the airtight terminal101to the first housing190.

In the first preferred embodiment, the circlips131,132are disposed in a mirror-image relation as shown inFIG. 2, but the disposition is not limited to this arrangement. For example, the circlips may be disposed in position opposing each other, which is defined as such a disposition that an angle made between the directions of the circlips131,132is more than 90 degrees.

In the first preferred embodiment, the flat contact surfaces131d,132dwhere the circlips131,132are in contact with the airtight terminal101lie in the same plane, but the contact surfaces131d,132dneed not be in the same plane. For example, they may be in parallel relation to each other.

In the first preferred embodiment, the airtight terminal101is fixed by two circlips131,132. Three or more circlips may be used for fixing the airtight terminal.FIG. 5, which corresponds toFIG. 2, shows an alternative embodiment wherein the airtight terminal301is fixed by three circlips331,332,333to the first housing390.

InFIG. 5, the angle made between any two adjacent circlips331,332,333is 120 degrees. Additionally, the circlips may be arranged in any other ways such that the angle made by any two adjacent circlips is more than 90 degrees. For fixing the airtight terminal301, at least two out of the circlips331,332,333should preferably be disposed in the opposite relation to each other. According to this embodiment, however, the circlips may be arranged such that any two adjacent circlips are not opposite to each other. Furthermore, in a structure having four or more circlips, at least two circlips should preferably be disposed in the opposite relation to each other. According to this embodiment, however, the circlips may be arranged such that any two adjacent circlips are not opposite to each other.

The first preferred embodiment relates to a structure for the motor compressor10, but it is not limited to a motor compressor. The present invention is also applicable to any other machines having a structure for fixing an airtight terminal to a housing. Though the foregoing description has been made with reference to a scroll type compressor, the invention is also applicable to a swash plate type compressor. In the first preferred embodiment, the airtight terminal101which is a mounted member in the first preferred embodiment is fixed to the first housing190which is a base member in the first preferred embodiment, but the mounted member and the base member are not limited to the airtight terminal and the housing in the above description. In the first preferred embodiment, the O-ring141is used as a seal member in the first preferred embodiment, but any other members or structures having a sealing function is usable. If a sealing function is not required, a seal member may be omitted.

The following will describe a second preferred embodiment of a mounting structure having an airtight terminal201according to the present invention with reference toFIG. 6. The seal structure in the first preferred embodiment is designed to seal the bottom surface of the airtight terminal101. On the other hand, the seal structure in the second preferred embodiment is arranged so as to seal the side surface of the airtight terminal201. The following will describe only the points that are different from the first preferred embodiment.

The support member202is made of a plate which is formed in a shape of a track, i.e. a shape consisting of two semicircles connected by parallel lines tangent to their endpoints, and has a thick portion202cat its periphery.

Unlike the O-ring groove141aof the first preferred embodiment which is formed in the surface at the step190a, the rectangular O-ring groove241ais formed in the large-diameter wall surface290cof the opening290bfor receiving therein the O-ring241. The O-ring241is press-fitted in its groove241abetween the outer peripheral surface202dof the support member202and the first housing290thereby to sealingly close the opening290bof the first housing290. Thus, the airtight terminal201is in contact with the O-ring241in a direction that is perpendicular to the extension of the support member202in the opening290b. Since the thick portion202cis formed at the periphery of the airtight terminal201, the outer peripheral surface202dof the support member202has a sufficient area for obtaining good sealing performance by contacting with the O-ring241.

To fix the airtight terminal201to the first housing290, C-shaped circlips231,232are used. The circlips231,232are in contact with the thick portion202cof the support member202to prevent outward movement of the support member202. The airtight terminal201according to the second preferred embodiment has such a structure that the outer peripheral surface202dof the support member202is in contact with the O-ring241, so that the support member202and the O-ring241may be disposed to overlap each other in the thickness direction of the first housing290. Accordingly, the mounting structure around the airtight terminal201may be made with a further reduced thickness.

The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.