Electric compressor

Abstract

An electric compressor includes: an electric motor; a compression mechanism driven by the electric motor; a housing accommodating the electric motor and the compression mechanism; an accommodation part provided on a sidewall of the housing and accommodating a drive circuit for driving the electric motor; a lid contacting the accommodation part and fastened to the accommodation part by a fastening portion; a sealing member sandwiched between the accommodation part and the lid so as to seal between them. The accommodation part has a wall standing from the sidewall of the housing, and a step is provided on a standing end surface of the wall orthogonal to a standing direction of the wall, at a midway position from an inside toward an outside of the accommodation part.

Claims

1. An electric compressor comprising: an electric motor; a compression mechanism driven by the electric motor; a housing accommodating the electric motor and the compression mechanism; an accommodation part provided on a sidewall of the housing and accommodating a drive circuit for controlling the electric motor; a lid contacting the accommodation part and fastened to the accommodation part by a fastening portion; a gasket sandwiched between the accommodation part and the lid so as to seal between them, wherein the accommodation part includes a wall standing from the sidewall of the housing, and a step is provided on a standing end surface of the wall orthogonal to a standing direction of the wall, at a midway position from an inside toward an outside of the accommodation part; the standing end surface includes a first standing end surface which is located further on the outside than the step and a second standing end surface which is located further on the inside than the step, the fastening portion passes through the first standing end surface, and the gasket is sandwiched between the lid and the second standing end surface; the accommodation part and the lid are fastened together by the fastening portion, and the first standing end surface and the lid directly contact each other; the gasket is formed of a metallic core material and a foam rubber layer disposed on both sides of the core material; a difference between the second standing and surface and the first standing end surface is set to satisfy the following formula:
(Ht)/(Tt)=0.2 to 0.32 where H: the difference between the second standing end surface and the first standing end surface: T: a total thickness of the gasket: t: a thickness of the core material; the second standing end surface has a fitting hole, into which a fitting portion extending upward is inserted; a lower portion of the fitting portion passes through an insertion hole provided in the gasket and is inserted into the fitting hole, and temporarily fixes the gasket to the second standing end surface; and an upper portion of the fitting portion inserted into the fitting hole fits an engaging hole formed in the lid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an exploded perspective view of an inverter-integrated electric compressor according to an embodiment of the present invention.

(2) FIG. 2A is a top view of a housing of the inverter-integrated electric compressor shown in FIG. 1.

(3) FIG. 2B is a top view of a gasket of the inverter-integrated electric compressor shown in FIG. 1.

(4) FIG. 3 is an enlarged view of a part of an end surface of an inverter accommodation part shown in FIG. 2A.

(5) FIG. 4 is a schematic cross-sectional view of a structure of the gasket shown in FIG. 2B.

DESCRIPTION OF EMBODIMENTS

(6) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

(7) FIG. 1 is an exploded perspective view showing one example of an inverter-integrated electric compressor according to the embodiment of the present invention. This inverter-integrated electric compressor 1 is used for an air conditioner of a vehicle, for example. In an aluminum alloy housing 2 of the compressor, a motor (electric motor) and a compressor (compression mechanism) driven by the motor (not shown) are accommodated. On a sidewall of the housing 2, an inverter accommodation part (accommodation part) 6 which accommodates an inverter device (drive circuit) for controlling the motor; a lid member (lid) 9 which contacts the inverter accommodation part 6 and is fastened to the inverter accommodation part 6 by bolts (fastening portion) 11; and a gasket (sealing member) 8 which is sandwiched between the inverter accommodation part 6 and the lid member 9 so as to seal between them, are provided.

(8) The housing 2 is constituted of: a motor-side housing 2a accommodating the motor; a compressor-side housing 2b (see FIG. 2A) mounted so as to block a front end opening of the motor-side housing 2a and accommodating the compressor (not shown); and the inverter accommodation part (accommodation part) 6 provided so as to be surrounded by a peripheral wall (wall) 7 standing from the sidewall of the motor-side housing 2a.

(9) The inverter accommodation part 6 forms an inverter box (not shown) together with the peripheral wall 7, which stands from the sidewall of the motor-side housing 2a and forms the inverter accommodation part 6, and the lid member 9, which is provided on an extension end of the peripheral wall 7 of the inverter accommodation part 6 and liquid-tightly mounted through the gasket 8.

(10) The lid member 9 contacts an end surface (standing end surface) 10 orthogonal to a standing direction of the peripheral wall 7 and is fastened by the bolts 11 to the peripheral wall 7 of the inverter accommodation part 6. For example, four bolts 11 are provided. When the lid member 9 is fastened to the peripheral wall 7 of the inverter accommodation part 6, the gasket 8 is sandwiched between them.

(11) The gasket 8 has a shape substantially the same as the end surface 10 of the peripheral wall 7, and for example, has a substantially rectangular shape when viewed from above as shown in FIG. 2B. The gasket 8 has such a shape that, when the gasket 8 is sandwiched between the lid member 9 and the end surface 10 of the peripheral wall 7, each corner of the gasket 8 is not sandwiched between the lid member 9 and a bolt seat surface 10a of the peripheral wall 7. Further, the substantially rectangular-shaped gasket 8 is provided with gasket positioning pin insertion holes 8c, to be described later, at two positions near the corner of two orthogonal sides.

(12) As shown in FIG. 4, such gasket 8 is formed of a metallic core material 8a provided approximately at the middle of its cross-section, and a foam rubber layer (elastic material) 8b disposed on top and bottom sides of the core material 8a.

(13) Here, Metafoam of NICHIAS Corporation or the like is used as the gasket 8, and an aluminum material is used for the core material 8a. The foam rubber layer 8b is preferably of NBR rubber.

(14) As shown in FIG. 2A, the inverter accommodation part 6, which is formed so as to be mounted on the upper sidewall of the motor-side housing 2a, has an outer periphery surrounded by the peripheral wall 7, and the peripheral wall 7 stands from the sidewall of the motor-side housing 2a so as to extend and open upward. The peripheral wall 7 stands from the sidewall of the motor-side housing 2a so as to extend upward. A step 12 is formed in each corner portion of the peripheral wall 7 which is the end surface 10 of the peripheral wall 7 and through which the bolt 11 passes.

(15) As shown in FIG. 3, the step 12 is formed at a midway position from an outside (the left side in FIG. 3) to an inside (the right side in FIG. 3) of the peripheral wall 7 of the inverter accommodation part 6. The end surface 10a located further outside than the step 12 (hereinafter referred to as bolt seat surface) is provided at a position further away from the sidewall of the motor-side housing 2a (see FIG. 2A) than an end surface 10b located further inside than the step 12 (hereinafter referred to as sealing seat surface), that is, the bolt seat surface 10a has a height H higher than a height of the sealing seat surface 10b.

(16) As shown in FIG. 2A, the bolt seat surface 10a is provided in each corner portion of the end surface 10 of the peripheral wall 7 of the inverter accommodation part 6 which forms a substantially rectangular shape. A bolt hole 13 through which the bolt 11 (see FIG. 1) passes is formed on the bolt seat surface 10a. This bolt seat surface 10a serves as a contact surface which touches a lower surface side of the lid member 9 (see FIG. 1) metal-to-metal when the lid member 9 is fastened by the bolt 11 to the peripheral wall 7 of the inverter accommodation part 6.

(17) The sealing seat surface 10b serves as a sealing surface which, together with the lid member 9, sandwiches the gasket 8 when the lid member 9 is fastened to the inverter accommodation part 6, and liquid-tightly seals between the inverter accommodation part 6 and the lid member 9.

(18) The difference H between the sealing seat surface 10b and the bolt seat surface 10a (size or height of the step 12) is calculated by the following formula (1) from its relationship with the gasket 8 sandwiched between the inverter accommodation part 6 and the lid member 9:
(Ht)/(Tt)=0.2 to 0.32(1)

(19) where H is a height of the step 12; T is a total thickness of the gasket 8 as shown in FIG. 4; and t is a thickness of the core material 8a of the gasket 8.

(20) For example, a gasket, of which the thickness t of the core material 8a is 0.25 mm, the total thickness T of the gasket 8 is 1.5 mm, and the thickness of the foam rubber layer 8b is 0.625 mm, is used as the gasket 8.

(21) The height H of the step 12 calculated from the formula (1) is determined taking into account the contact pressure required when sandwiching the gasket 8 between the sealing seat surface 10b and the lid member 9, and machinability of the step 12. This is because too small a contact pressure acting on the gasket 8 causes the liquid-tightness between the peripheral wall 7 and the lid member 9 to be poor, while too large a contact pressure causes the height H of the step 12 to be too small, making machining of the step 12 difficult to manage.

(22) As shown in FIG. 1, the sealing seat surface 10b has a positioning pin insertion hole 15 provided at two positions, into which the positioning pin (fitting portion) 14 extending upward is inserted. Each positioning pin insertion hole 15 is provided at a position near each corner portion of the two orthogonal sides of the peripheral wall 7 which is the sealing seat surface 10b and the end surface 10 of the peripheral wall 7.

(23) The positioning pin 14 is inserted into the positioning pin insertion hole 15 during the assembly of the inverter-integrated electric compressor 1. The positioning pin 14 inserted into the positioning pin insertion hole 15 is used for temporarily fixing the gasket 8 to the sealing seat surface 10b. The positioning pin 14 passes through the gasket positioning pin insertion hole 8c provided in the gasket 8, and can temporarily fix the gasket 8 to the sealing seat surface 10b. The positioning pin 14, having temporarily fixed the gasket 8 to the sealing seat surface 10b, fits an engaging hole (not shown) formed in the lid member 9 upon fastening the lid member 9 to the peripheral wall 7 of the inverter accommodation part 6.

(24) As described above, according to the inverter-integrated electric compressor 1 of the present invention, the following effects can be obtained.

(25) The step 12 is provided on the end surface (standing end surface) 10 of the peripheral wall (wall) 7 forming the inverter accommodation part (accommodation part) 6, which is formed on the sidewall of the motor-side housing (housing) 2a and accommodates the inverter device (drive circuit) for controlling the motor (electric motor), so that the gasket (sealing member) 8 is sandwiched between the lid member (lid) 9 and the sealing seat surface (standing end surface) 10b located further inside than the step 12. In addition, the bolt (fastening portion) 11 passes through the bolt seat surface (standing end surface) 10a located further outside than the step 12 so as to fasten together the lid member 9 and the peripheral wall 7 of the inverter accommodation part 6. Thanks to these configurations, when the lid member 9 and the peripheral wall 7 of the inverter accommodation part 6 are fastened together by the bolt 11, the peripheral wall 7 and the lid member 9 directly contact (touch metal-to-metal) each other in the bolt seat surface 10a, allowing the load of the bolt 11 to be received directly by the bolt seat surface 10a of the peripheral wall 7. Accordingly, even when the contact pressure of the gasket 8 changes, the axial force acting on the bolt 11 does not change. Thus, the liquid-tightness of the inverter-integrated electric compressor (electric compressor) 1 can be maintained.

(26) By using the gasket 8 having the foam rubber layer (elastic material) 8b disposed on both sides of the aluminum (metallic) core material 8a, a deformation amount required for applying a desired contact pressure to the gasket 8 can be made smaller, compared to a case where a gasket of the same thickness having no core material 8a made of metal such as aluminum is used. Accordingly, the height (size) H of the step 12 formed on the end surface 10 of the peripheral wall 7 can be made a moderate height. As the step 12 is difficult to form when the height H is too low (too small), by making the height H of the step 12 a moderate height, maintenance of the liquid-tightness of the inverter-integrated electric compressor 1 is facilitated.

(27) Further, by using the gasket 8 having the foam rubber layer 8b disposed on both sides of the aluminum core material 8a, the assembly work of the inverter-integrated electric compressor 1 can be facilitated, compared to a case where a liquid gasket (not shown) is used.

(28) Moreover, compared to a case where a gasket having no core material 8a made of metal such as aluminum is used, the fastening interval between the bolts 11 fastening the lid member 9 and the peripheral wall 7 can be made longer. Accordingly, the number of the bolts 11 can be made smaller. Thus, the assembly work of the inverter-integrated electric compressor 1 can be facilitated.

(29) The positioning pin (fitting portion) 14 which passes through the gasket 8 and can fit the lid member 9 is provided on the sealing seat surface 10b. Accordingly, when assembling the inverter-integrated electric compressor 1, the gasket 8 can be temporarily positioned by passing the positioning pin 14 through the gasket 8. Thus, the assembly work of the inverter-integrated electric compressor 1 can be facilitated.

REFERENCE SIGNS LIST

(30) 1 electric compressor (inverter-integrated electric compressor) 2, 2a housing (housing, electric-motor-side housing) 6 accommodation part (inverter accommodation part) 7 wall (peripheral wall) 8 sealing member (gasket) 9 lid (lid member) 10, 10a, 10b standing end surface (end surface, bolt seat surface, sealing seat surface) 11 fastening portion (bolt) 12 step