JP3243014U - electric compressor - Google Patents

Abstract

An electric compressor is provided that suppresses abrasion of a pump housing and avoids deterioration of pump performance even when strong side pressure acts on an outer rotor and an inner rotor that constitute a trochoid type oil pump.
A pump housing (5) is provided in a housing that accommodates a compression mechanism and an electric motor, an outer rotor (31) is arranged in a bottomed pump accommodating portion (55) formed in the pump housing (5), and an inner rotor (32) is accommodated in the outer rotor. A cover member that rotates the inner rotor by the drive shaft 4 of the electric motor, rotates each rotor in a predetermined rotational direction, increases or decreases the volume of the pump chamber 34 formed between the rotors, and closes the open end of the pump accommodating portion. A trochoid type oil pump 3 for discharging oil from a pump chamber through a discharge port 72 formed between the pump housing portion 55a and a sliding plate 33 is provided between the bottom surface 55a of the pump accommodating portion and the trochoid type oil pump. .
[Selection drawing] Fig. 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric compressor having a trochoidal oil pump, and more particularly to an electric compressor having a configuration for avoiding performance deterioration of the trochoidal oil pump.

As a conventional electric compressor provided with a trochoid type oil pump, the one disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2-27186) is well known.
A trochoid type oil pump used in this electric compressor has a bottomed pump accommodating portion (eccentric hole) formed in a housing, an open end of the pump accommodating portion is covered with a cover member (frame), and an outer rotor and an inner rotor are provided inside. is configured to accommodate

The pump accommodating portion is formed eccentrically with respect to the drive shaft that connects the orbiting scroll, the outer rotor is rotatably supported in the pump accommodating portion, and the inner rotor is eccentrically attached to the drive shaft within the outer rotor. Fixed. Therefore, the inner rotor is rotatably inserted into the outer rotor in an eccentric state and meshed so as to form a pump chamber between the peripheral surfaces of the outer rotor and the inner rotor (between the inner teeth of the outer rotor and the outer teeth of the inner rotor). I have to.

A suction port facing the pump chamber is formed in the housing, and a discharge port facing the pump chamber is formed in the cover member (frame) that closes the open end of the pump accommodating portion. oil is delivered to the

JP-A-2-27186

However, in a conventional electric compressor equipped with a trochoid type oil pump, the discharge pressure of the discharge port acts as side pressure on the end surfaces of the outer rotor and the inner rotor facing the cover member, so that the side surfaces of these rotors facing the housing are not pumped. It is strongly pressed against the bottom surface of the container.

In particular, an electric compressor for a vehicle may operate at a high rotation speed in order to rapidly cool the interior of the vehicle. In this case, since the trochoidal oil pump is also driven at high speed, the amount of oil discharged increases, and the oil pressure in the discharge port increases, which also increases the side pressure, and these rotors are strongly pressed against the bottom surface of the pump accommodating portion.

In general, aluminum is used for the housing of electric compressors for vehicles in order to reduce weight. is used. Therefore, when each rotor is strongly pressed against the bottom surface of the pump accommodating portion as the trochoidal oil pump rotates, the housing (bottom surface of the pump accommodating portion), which has relatively low wear resistance, wears, resulting in a decrease in pump performance. I have an inconvenience.

As a countermeasure against this, it is conceivable to increase the clearance between the trochoidal oil pump and the pump housing (the bottom surface of the pump accommodating portion) as a countermeasure against wear.
However, when the clearance is widened, there is a problem that oil leaks from the clearance and the performance of the pump deteriorates, requiring a pump with a higher capacity.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and suppresses wear of the housing even when strong side pressure acts on the outer rotor and the inner rotor constituting the trochoid type oil pump, thereby avoiding deterioration of the pump performance. A main object of the present invention is to provide an electric compressor capable of improving reliability.

In order to achieve the above object, the electric compressor (1) according to the present invention includes:
a housing (10) containing a compression mechanism for compressing a working fluid and an electric motor (2) for driving the compression mechanism;
a pump housing (5) fixed to or integrally formed with said housing (10);
a bottomed pump housing portion (55) formed in the pump housing (5);
an outer rotor (31) rotatably disposed in the pump housing (55) and having a plurality of internal teeth (31a); An inner rotor (32) having a plurality of external teeth (32a) is provided, and a drive shaft (4) of the electric motor (2) inserted into the pump housing (55) rotates the inner rotor (32), thereby By rotating each rotor (31, 32) in a predetermined rotational direction, the volume of the pump chamber (34) formed between the internal teeth (31a) and the external teeth (32a) is increased or decreased to increase or decrease the amount of oil. A trochoidal oil pump (3) for pumping (24);
An electric compressor (1) comprising
The trochoidal oil pump (3) is supplied through a suction port (71) formed between the pump housing (5) or the cover member (7) that closes the open end of the pump accommodating portion (55). The oil (24) is sucked into the pump chamber (34), and the oil (24) is discharged from the pump chamber (34) through a discharge port (72) formed between the cover member (7) and the cover member (7). is a
A slide plate (33) is provided between the bottom surface (55a) of the pump accommodating portion (55) of the pump housing (5) and the trochoid type oil pump (3).

Therefore, even if the discharge pressure from the discharge port acts as side pressure on the end surfaces of the outer rotor and the inner rotor facing the cover member, and the rotors are strongly pressed against the housing (bottom surface of the pump accommodating portion), the bottom surface of the pump accommodating portion of the pump housing will not be affected. and the trochoidal oil pump (outer rotor and inner rotor), it is possible to prevent wear of the housing (bottom surface of the pump accommodating portion).
Here, the sliding plate is preferably made of a material having higher wear resistance than the pump housing, such as SK material (carbon tool steel).

Moreover, it is preferable that the sliding plate (33) is provided with a protrusion (33b) for preventing the rotation of the sliding plate (33).
With such a configuration, the trochoidal oil pump can also prevent abrasion of the pump housing (bottom surface of the pump accommodating portion) due to movement of the sliding plate.
In the trochoid type oil pump, the pump accommodating portion is provided eccentrically with respect to the axis of the drive shaft. It can be blocked by the shaft. However, contacting the sliding plate with the drive shaft causes problems such as contamination due to abrasion powder. prevention).

Various configurations are conceivable for providing the projections for preventing the rotation of the slide plate. An engagement groove (55c) is formed in the surface (55b) along the axial direction of the drive shaft (4), and the protrusion (33b) is engaged with the engagement groove (55c) to prevent rotation. is preferable because it is easy to manufacture.
At this time, in order to ensure the strength of the housing, the engagement grooves are preferably provided at locations where the thickness between the outer peripheral surface of the pump housing and the inner peripheral surface of the pump accommodating portion is relatively thick.

As described above, in the electric compressor in which the discharge port facing the pump chamber of the trochoidal oil pump is formed in the cover member that closes the open end of the pump accommodating portion, the trochoidal oil pump and the pump accommodating portion of the pump housing are formed. Since the slide plate is provided between the bottom surface and the bottom surface, it is possible to avoid abrasion of the pump housing, suppress deterioration of the pump performance, and improve the reliability of the oil pump.

FIG. 1 is a cross-sectional view showing an embodiment of an electric compressor equipped with a trochoid-type oil pump according to the present invention, (a) is a cross-sectional view showing the electric motor and the trochoid-type oil pump, ( b) is a cross-sectional view taken along line BB, and (b) is a cross-sectional view taken along line AA of (a). FIG. 2 is an enlarged sectional view showing a trochoid type oil pump used in the electric compressor according to the present invention and its surroundings. FIG. 3 is a perspective view showing the trochoid type oil pump used in the electric compressor according to the present invention and its peripheral components, where (a) shows a pump housing, a sliding plate, a trochoid type oil pump (inner rotor, 2B is an exploded perspective view of the cover member, the outer rotor) and the cover member as seen from the cover member side, and (b) is an exploded perspective view of the cover member, the trochoid type oil pump, and the slide plate as seen from the slide plate side. FIG. 4(a) is a front view showing the portion of the pump accommodating portion of the pump housing, FIG. 4(b) is a front view showing the sliding plate accommodated in the pump accommodating portion, and FIG. 4(c) is a trochoid 1 is a front view of a type oil pump; FIG.

An embodiment of an electric compressor 1 according to the present invention will be described below with reference to the drawings.

In FIG. 1, an electric compressor 1 is a compressor suitable for a vehicle refrigeration cycle using a refrigerant as a working fluid. An electric motor 2 for driving the compression mechanism is arranged on the right side of the figure. The housing 10 includes a compression mechanism accommodation housing (not shown) that accommodates a compression mechanism, an electric motor accommodation housing 11 that accommodates an electric motor 2 that drives the compression mechanism, and an inverter accommodation housing 12 that accommodates an inverter device (not shown) that drives and controls the electric motor 2. These storage housings are axially fastened by fastening bolts (not shown).
Since the compression mechanism is known per se, the description is omitted, but the compression mechanism may be of a scroll type, a vane type, or a swash plate type.

The electric motor housing 11 includes a cylindrical motor fixing portion 11a to which the electric motor 2 is fixed, and a main shaft support portion 41 which is provided on the side facing the compression mechanism housing (not shown) and supports the drive shaft 4 of the electric motor 2. It is integrally formed with the end plate 11b.
The inverter housing 12 is integrally formed with a cylindrical inverter housing wall 12 a surrounding an inverter device (not shown) and an end plate 12 b provided on the side facing the motor housing 11 .
Therefore, the end plates 11b and 12b formed on the motor housing 11 and the inverter housing 12 form a motor housing portion 11c for housing the motor 2 inside the housing 10. As shown in FIG.

In this example, the electric motor accommodating housing 11 is integrally formed from the tubular motor fixing portion 11a to which the electric motor 2 is fixed to the open end portion to which the inverter accommodating housing 12 is assembled. has a circular cross-section, and a portion closer to the opening end than the motor fixing portion 11a (the end facing the inverter housing 12) has a quadrangular cross-section.
Further, the inverter accommodating housing 12 has an inverter accommodating portion 12c defined by covering the open end with the lid 13 with a bolt or the like (not shown).

The electric motor 2 operates as a motor that drives the compression mechanism and also as a motor that drives a trochoid type oil pump 3 that supplies oil 24, which will be described later.
The electric motor 2 has a stator 21 and a rotor 22 that rotates within the stator 21 . The stator 21 is a stator core around which windings are wound, and is fixed to the inner peripheral surface 55 b of the electric motor housing 11 . The rotor 22 is a magnet rotor in which permanent magnets are embedded, and is fixed to the drive shaft 4 . One end of the drive shaft 4 is connected to the shaft of a compression mechanism (not shown) and is rotatably supported by a main shaft support 41 provided on the end plate 11b of the motor housing 11. As shown in FIG. The other end of the drive shaft 4 is formed to have a small diameter and is rotatably supported by a sub shaft support 42 provided in a pump housing 5 in which a trochoid type oil pump 3 (to be described later) is accommodated. It is connected to the inner rotor 32 of the type oil pump 3 .

The pump housing 5 is provided within the electric motor housing housing 11 . The pump housing 5 may be formed integrally with the electric motor housing 11, or may be formed separately from the electric motor housing 11 and fixed to the electric motor housing 11. In the example, it is formed separately and fixed to the electric motor housing housing 11 by bolting.

2 to 4, the pump housing 5 includes a cylindrical portion 52 having a partition wall 51 formed with a shaft insertion hole 51a through which the drive shaft 4 is inserted. three support arms 53 (first support arm 53a extending obliquely upward) extending radially outward at an interval of approximately 90 degrees from the outer peripheral surface of the . A second support arm 53b extending obliquely downward with an interval of 90 degrees, and a third supporting arm 53c extending obliquely downward with an interval of approximately 90 degrees from the second support arm 53b). and

Inside the tubular portion 52 , a bottomed bearing accommodating portion 54 for accommodating the sub-shaft support portion 42 supporting the drive shaft 4 is formed in a portion closer to the electric motor 2 than the partition wall 51 . On the opposite side of the bearing housing portion 54, a lower pump housing portion 55 for housing the trochoid type oil pump 3 is formed.
Each support arm 53 of the pump housing 5 is fixed to the electric motor housing 11 so that the axis of the bearing housing 54 is aligned with the axis O of the drive shaft 4 . Therefore, the bearing accommodating portion 54 is formed concentrically with the axis O of the drive shaft 4 . On the other hand, the pump accommodating portion 55 is formed eccentrically with respect to the axis O of the drive shaft 4, as shown in FIG. 4(a).

The trochoid type oil pump 3 includes an outer rotor 31 rotatably accommodated in a pump accommodating portion 55 and having a plurality of internal teeth 31a, and a plurality of external teeth 32a accommodated in the outer rotor 31 and meshing with the plurality of internal teeth 31a. and an inner rotor 32 having.

Between the trochoid type oil pump 3 accommodated in the pump accommodating portion 55 and the partition wall 51 (the bottom surface 55a of the pump accommodating portion 55), a sliding plate 33 is arranged so as to match the shape of the bottom surface of the pump accommodating portion 55. ing. The slide plate 33 is mounted in surface contact with the bottom surface 55a of the pump accommodating portion 55, that is, the partition wall 51. The slide plate 33 is aligned with the shaft insertion hole 51a formed in the partition wall 51. A shaft insertion hole 33a through which the drive shaft 4 is inserted is formed at a position where the drive shaft 4 is inserted. The sliding plate 33 is made of a material having higher wear resistance than the pump housing 5, such as SK material (carbon tool steel). It is formed somewhat larger than the diameter of the shaft 4 .
Further, the sliding plate 33 is provided with a protrusion 33b that prevents the sliding plate 33 from rotating. In this example, the protrusion 33b is formed by protruding a part of the outer peripheral portion of the sliding plate 33 radially outward.

On the other hand, in the pump housing 5, an engagement groove 55c extends along the axial direction of the drive shaft 4 from the open end of the pump housing portion 55 to the bottom surface in the inner peripheral surface 55b of the pump housing portion 55 corresponding to the protrusion 33b. 55a. The engagement groove 55c is formed at a portion where the thickness between the outer peripheral surface of the cylindrical portion 52 and the inner peripheral surface 55b of the pump housing portion 55 is relatively thick. In this example, it is formed on the inner peripheral surface 55b (the inner peripheral surface 55b on the side close to the axis O) opposite to the side where the pump accommodating portion 55 is eccentric with respect to the shaft insertion hole 51a of the partition wall 51. ing. The slide plate 33 is prevented from rotating in the circumferential direction by engaging the protrusion 33b with the engagement groove 55c.

The drive shaft 4 inserted into the pump accommodating portion 55 through the shaft insertion hole 51a of the partition wall 51 and the shaft insertion hole 33a of the slide plate 33 is inserted into the shaft insertion hole 32b formed at the center of the inner rotor 32. It is fitted inside and rotates integrally with the inner rotor 32 .
Therefore, when the drive shaft 4 rotates, the inner rotor 32 rotates accordingly, and the outer teeth 32a of the inner rotor 32 mesh with the inner teeth 31a of the outer rotor 31 to rotate the outer rotor 31 in the same direction. As a result, the volume of the pump chamber 34 formed between the inner teeth 31a and the outer teeth 32a increases and decreases as the rotors 31 and 32 rotate.

The open end of the pump accommodating portion 55 is closed by the cover member 7 . The cover member 7 is bolted to a screw hole 56 provided in the outer edge of the cylindrical portion 52 of the pump housing 5 . A suction port 71 and a discharge port 72 facing 34 are formed.

That is, on the surface of the cover member 7 facing the pump accommodating portion 55, a raised portion 73 is formed which is formed in a substantially semicircular shape in plan view and faces the trochoid type oil pump 3 with a predetermined clearance. , is formed by a space surrounded by the inner peripheral surface 55b of the pump accommodating portion 55 and the trochoid type oil pump 3, in which the arc-shaped portion where the raised portion 73 is not formed is formed. The discharge port 72 includes an arcuate recess 72a formed in the raised portion 73 of the cover member 7 and a groove extending radially inwardly from the arcuate recess 72a to a position aligned with the axial center of the drive shaft 4. 72b is covered with the trochoidal oil pump 3. As shown in FIG.

The suction port 71 is formed to communicate with the pump chamber 34 in the suction process in which the volume of the pump chamber 34 of the trochoid type oil pump 3 gradually increases. It communicates with the pump chamber 34 in a discharge process in which the volume of the pump chamber 34 is gradually reduced.

The downwardly extending third support arm 53c extends to a position where its lower end is immersed in the oil 24 stored in the oil storage chamber 23 provided in the lower portion of the electric motor housing 11 . The third support arm 53c is formed with an oil introduction hole 57 whose one end opens to the oil reservoir chamber 23 and whose other end opens to the suction port 71 at the inner peripheral surface 55b of the pump accommodating portion 55 .

Therefore, when the drive shaft 4 rotates and the trochoid type oil pump 3 rotates, the oil 24 stored in the oil storage chamber 23 is pumped by the trochoid type oil pump 3 and flows through the oil introduction hole 57 to the intake port. 71 and introduced into the pump chamber 34 from the suction port 71 during the suction process. After that, the oil 24 introduced into the pump chamber 34 is delivered to the arc-shaped concave portion 72a of the discharge port 72 in the compression process in which the volume of the pump chamber 34 is reduced, and then through the groove portion 72b to the axial center of the drive shaft 4. is supplied to an oil hole 4a formed in the inner wall of the cylinder, and sent to each sliding portion from the oil hole 4a.

At this time, since the discharge pressure of the discharge port 72 acts as side pressure on the end surfaces of the outer rotor 31 and the inner rotor 32 facing the cover member 7, the rotors (outer rotor 31, inner rotor 32) move toward the pump housing 5 (pump accommodating portion 55). is strongly pressed against the side of the partition wall 51) which becomes the bottom surface 55a of the . However, since the sliding plate 33 is provided between the trochoid type oil pump 3 (the outer rotor 31 and the inner rotor 32) and the pump housing 5 (the partition wall 51 forming the bottom surface 55a of the pump housing portion 55), the trochoid type The oil pump 3 is not directly pressed against the pump housing 5 (the partition wall 51 forming the bottom surface 55a of the pump accommodating portion 55), and wear of the pump housing 5 can be prevented. Further, since the slide plate 33 is made of a material having higher wear resistance than the pump housing 5, even if the trochoid type oil pump 3 is strongly pressed against the slide plate 33, the slide plate 33 will not wear out. can also be suppressed. Therefore, it is possible to avoid deterioration of the pump performance.

Moreover, since the protrusion 33b for preventing the rotation of the sliding plate 33 is provided on the outer edge of the sliding plate 33, the sliding plate 33 is prevented from rotating with the rotation of the trochoid type oil pump 3. Also, abrasion of the pump housing 5 (the partition wall 51 forming the bottom surface 55a of the pump accommodating portion 55) due to the movement of the sliding plate 33 can be prevented. Further, it is possible to avoid the problem that the movement of the slide plate 33 causes the inner peripheral surface of the shaft insertion hole 33a of the slide plate 33 to come into contact with the drive shaft 4 and generate abrasion powder.

The sliding plate 33 has an engaging groove 55c formed in the inner peripheral surface 55b of the pump accommodating portion 55 along the axial direction of the drive shaft 4, and a protrusion 33b provided on the outer edge of the sliding plate 33 is engaged with the engaging groove 55c. Since it is engaged with the engagement groove 55c to prevent rotation, the rotation of the sliding plate 33 can be reliably prevented with a simple structure. Moreover, it is possible to visually confirm whether or not the rotation is prevented when the sliding plate 33 is assembled.

Furthermore, since the engagement groove 55c is formed at a relatively thick portion between the outer peripheral surface of the cylindrical portion 52 and the inner peripheral surface 55b of the pump accommodating portion 55, the engagement groove 55c is formed. Therefore, the strength of the pump housing 5 is not affected.

In the above-described embodiment, the trochoidal oil pump 3 sucks the oil 24 into the pump chamber 34 through the suction port 71 formed between the trochoidal oil pump 3 and the cover member 7 closing the open end of the pump accommodating portion 55. Although the example is shown, even when the oil 24 is sucked into the pump chamber 34 through the suction port formed between the pump housing 5 and the discharge port 72 formed between the cover member 7, Since a strong side pressure acts on the trochoid type oil pump 3 toward the pump housing 5 (the partition wall 51 that forms the bottom surface 55a of the pump housing portion 55), the bottom surface 55a of the pump housing portion 55 and the trochoidal oil pump 3 do not interfere with the intake port. A configuration in which a slide plate 33 is provided between the die oil pumps 3 may be employed.

Furthermore, in the above-described embodiment, the trochoid type oil pump 3 pumps the oil 24 stored in the oil storage chamber 23 to the pump chamber 34 through the oil introduction hole 57 formed in the third support arm 53c and the suction port 71. shows an example in which the oil 24 is sucked, but a cylindrical oil introduction pipe (not shown) separate from the support arm 53 is immersed in the oil 24 stored in the oil reservoir chamber 23 from the suction port 71 of the pump housing 5. By forming up to the position, the oil introduction hole may be formed by the oil introduction pipe.

1 Electric Compressor 4 Drive Shaft 5 Pump Housing 7 Cover Member 10 Housing 31 Outer Rotor 31a Internal Teeth 32 Inner Rotor 32a External Teeth 33 Sliding Plate 33b Projection 34 Pump Chamber 55 Pump Housing 55c Engagement Groove 71 Suction Port 72 Discharge Port

Claims (3)

a housing (10) containing a compression mechanism for compressing a working fluid and an electric motor (2) for driving the compression mechanism;
a pump housing (5) fixed to or integrally formed with said housing (10);
a bottomed pump housing portion (55) formed in the pump housing (5);
an outer rotor (31) rotatably disposed in the pump housing (55) and having a plurality of internal teeth (31a); An inner rotor (32) having a plurality of external teeth (32a) is provided, and a drive shaft (4) of the electric motor (2) inserted into the pump housing (55) rotates the inner rotor (32), thereby By rotating each rotor (31, 32) in a predetermined rotational direction, the volume of the pump chamber (34) formed between the internal teeth (31a) and the external teeth (32a) is increased or decreased to increase or decrease the amount of oil. A trochoidal oil pump (3) for pumping (24);
An electric compressor (1) comprising
The trochoidal oil pump (3) is supplied through a suction port (71) formed between the pump housing (5) or the cover member (7) that closes the open end of the pump accommodating portion (55). The oil (24) is sucked into the pump chamber (34), and the oil (24) is discharged from the pump chamber (34) through a discharge port (72) formed between the cover member (7) and the cover member (7). is a
An electric compressor, wherein a slide plate (33) is provided between a bottom surface (55a) of the pump accommodating portion (55) of the pump housing (5) and the trochoid type oil pump (3). The electric compressor according to claim 1, wherein the sliding plate (33) is provided with a projection (33b) for preventing rotation of the sliding plate (33). The projection (33b) is provided on the outer peripheral portion of the sliding plate (33),
An engagement groove (55c) is formed in the inner peripheral surface (55b) of the pump accommodating portion (55) along the axial direction of the drive shaft (4),
The electric compressor according to claim 2, wherein the protrusion (33b) is engaged with the engagement groove (55c) to prevent rotation.

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