JP2011202641A - Electric compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of an electric compressor having a thrust disc on which cancelling thrust operates.SOLUTION: In the electric compressor 1, a thrust canceller mechanism 50 on which cancelling thrust operates to reduce thrust on a rotating shaft 20 resulting from the rotation of an impeller 10, includes the thrust disc 51 provided on the rotating shaft 20 between the impeller 10 and a rotor 8 of an electric motor, and a pressure chamber wall 53 forming a pressure chamber 52 storing the thrust disc 51. The thrust disc 51 partitions the pressure chamber 52 into a high pressure chamber 52a located on the side of the impeller 10 and a low pressure chamber 52b located on the side of the rotor 8. Into the high pressure chamber 52a, pressure air compressed by the impeller 10 is guided through a pressure passage 54. The cancelling thrust is generated by a pressure difference between pressure in the high pressure chamber 52a and pressure in the low pressure chamber 52b.

Description

  The present invention relates to an electric compressor including an impeller driven by an electric motor. And this electric compressor is equipped in a fuel cell system, for example, and is used in order to compress the air as oxidant gas supplied to a cathode side electrode.

An electric compressor is known that includes an impeller that rotates integrally with a rotating shaft that is driven to rotate by an electric motor, and a thrust disk that acts on a canceling thrust force that reduces a thrust force that acts on the rotating shaft due to the rotation of the impeller. (For example, refer to Patent Document 1).
In general, a foil bearing in which an air film is formed between the rotating shaft and the rotating shaft is well known as a rotating shaft bearing device (see, for example, Patent Documents 2 and 3).

JP-A-4-86395 Japanese National Patent Publication No. 11-503811 JP 2001-295836 A

In the electric compressor, when the thrust disk is disposed in the axial direction on the opposite side of the impeller across the electric motor, the pressure passage for guiding the pressurized gas compressed by the impeller to the pressure chamber in which the thrust disk is stored The pressure length in the passage increases. For this reason, in order to generate the required canceling thrust force, it is necessary to compensate for the pressure drop due to the pressure loss. For this reason, when the thrust disk is enlarged, the electric compressor becomes larger and the weight increases.
In addition, the compressor is increased in size in the axial direction by the amount of the thrust disk.

  The present invention has been made in view of such circumstances, and an object thereof is to reduce the size and weight of an electric compressor including a thrust disk on which a cancel thrust force acts.

  According to the first aspect of the present invention, a housing (2) that rotatably supports a rotating shaft (20) that is rotationally driven by a rotor (8) of an electric motor (7), and the rotating shaft (20) rotate integrally. An impeller (10), and a thrust canceller mechanism (50) on which a cancel thrust force (Fb) that reduces the thrust force (Fa) acting on the rotating shaft (20) due to the rotation of the impeller (10) acts. The thrust canceller mechanism (50) includes: a thrust disk (51) provided on the rotating shaft (20) between the impeller (10) and the rotor (8) in the axial direction. And a pressure chamber wall (53) forming a pressure chamber (52) in which the thrust disc (51) is accommodated, and the thrust disc (51) includes the pressure chamber (52). The high pressure chamber (52a) located on the impeller (10) side and the low pressure chamber (52b) located on the rotor (8) side are partitioned in the axial direction, and the impeller is placed in the high pressure chamber (52a). The pressurized gas compressed by (10) is guided through the pressure passage (54), and the cancel thrust force (Fb) is a differential pressure between the pressure of the high pressure chamber (52a) and the pressure of the low pressure chamber (52b). Is an electric compressor generated by

According to this, the thrust disk is arranged in the axial direction using the space between the impeller and the rotor of the motor, and further, the thrust disk is separated from the pressure chamber wall in the direction of the cancel thrust force by the cancel thrust force. As a result, the thrust bearing can be omitted, and the electric compressor can be downsized in the axial direction.
Furthermore, this arrangement of the thrust disk allows the high-pressure chamber to be positioned closer to the impeller than the rotor in the axial direction, so that the length of the pressure passage leading the pressurized fluid to the high-pressure chamber can be shortened. The pressure loss of the pressurized fluid can be reduced. As a result, high pressure fluid can be supplied to the high pressure chamber as much as the pressure loss is reduced, so that the thrust disk can be downsized compared to when the pressure loss is large in order to obtain the required canceling thrust force. Thus, the electric compressor can be reduced in size and weight.

The invention according to claim 2 is the electric compressor according to claim 1, wherein the pressure passage (54) is the rotor (8) in the axial direction in the scroll passage (15) through which the pressurized fluid flows. ) At a portion close to the pressure fluid outlet 54a, and the entire pressure passageway 54 is radially between the outlet 54a and the high pressure chamber 52a. It is located between the impeller (10) and the thrust disk (51) in the axial direction.
According to this, the entire pressure passage is located between the outlet and the high-pressure chamber in the radial direction and between the impeller and the thrust disk in the axial direction, so that the passage length of the pressure passage is shortened. As a result, the pressure loss of the pressurized fluid in the pressure passage can be reduced, and the thrust disk can be downsized.

The invention according to claim 3 is the electric compressor according to claim 1 or 2, wherein the pressure passage (54) is provided with a pressure adjusting portion (55) for adjusting the pressure of the pressurized gas. It is.
According to this, since the pressure of the pressurized gas led to the high pressure chamber is adjusted by the pressure adjusting unit, even when the pressure of the pressurized gas fluctuates, the variation of the cancel thrust force can be suppressed, and the thrust canceller mechanism Can stabilize the function.

Invention of Claim 4 is an electric compressor of any one of Claim 1 to 3, Comprising: In the said low pressure chamber (52b), the said low pressure chamber (52b) in the said pressure chamber wall (53). A foil bearing (58) is provided on the low-pressure chamber wall (53b) forming the upper pressure chamber wall or on the thrust disk (51) facing the low-pressure chamber wall (53b) in the axial direction.
According to this, the axial movement of the thrust disk is restricted by the air film formed by the foil bearing even when the pressure in the high pressure chamber temporarily becomes high due to the pressure fluctuation of the pressurized gas. Generation of contact between the disk and the pressure chamber wall can be prevented or suppressed.

A fifth aspect of the present invention is the electric compressor according to any one of the first to fourth aspects, wherein a leak passage (59) for allowing the gas in the low pressure chamber (52b) to escape is provided.
According to this, since the gas in the low pressure chamber flows out through the leak passage, it becomes easy to lower the pressure in the low pressure chamber, and it becomes easy to form a cancel thrust force having a magnitude that reduces the thrust force.

  According to the present invention, it is possible to reduce the size and weight of an electric compressor including a thrust disk on which a cancel thrust force acts.

It is sectional drawing which shows the whole electric compressor which is embodiment of this invention. It is a figure explaining the module of the electric compressor of FIG. It is a principal part enlarged view of FIG.

Embodiments of the present invention will be described below with reference to FIGS.
An electric compressor 1 according to an embodiment of the present invention shown in FIG. 1 is a centrifugal compressor that is provided in a fuel cell system mounted on a vehicle as a machine and supplies air as an oxidant gas.
The electric compressor 1 includes a housing 2, an electric motor 7 housed in the housing 2, a rotating shaft 20 that is rotationally driven by the electric motor 7, and a bearing device 40 that rotatably supports the rotating shaft 20 on the housing 2. The impeller 10 that rotates integrally with the rotating shaft 20, the fastening member 30 that integrally connects the rotating shaft 20 and the impeller 10, and the thrust force that acts forward on the rotating shaft 20 due to the rotation of the impeller 10. And a thrust canceller mechanism 50 in which a cancel thrust force Fb for reducing Fa acts rearward.

  In the present invention and the embodiment, the axial direction is a direction parallel to the rotation center line L of the rotary shaft 20, and the radial direction and the circumferential direction are a radial direction and a circumferential direction around the rotation center line L, respectively. Suppose that For convenience, the front-rear direction is a direction parallel to the axial direction, and the front is a direction in which the impeller 10 is positioned in the axial direction with respect to the rotary shaft 20 or the rotor 8 of the electric motor 7.

The housing 2 accommodates an impeller 10 having a plurality of blades 10a and forms an air supply passage 11 through which air as a gas sucked and compressed by the impeller 10 flows, and a rotor 8 and a stator of an electric motor 7. 9 and a motor housing 4 coupled to the impeller housing 3 and an end housing 5 coupled to the motor housing 4. The motor housing 4 is disposed between the impeller housing 3 and the end housing 5 in the axial direction.
The impeller housing 3, the motor housing 4 and the end housing 5 form an internal space 6 of the electric compressor 1.

  An air supply passage 11 serving as a gas supply passage communicating with the oxidant gas supply system of the fuel cell system is located upstream of the impeller 10 and takes in air, and the air from the inlet passage 12 It has the compression flow path 13 compressed by the impeller 10, and the exit flow path located downstream from the impeller 10 and through which the pressurized air as the pressurized gas compressed by the impeller 10 flows. The outlet flow path includes a diffuser flow path 14 that continues downstream of the compression flow path 13 and a scroll flow path 15 that continues downstream of the diffuser flow path 14.

  The impeller housing 3 includes a front housing 3a that forms an inlet channel 12 and a compression channel 13, and a rear housing 3b that is coupled to the front housing 3a by a bolt B1. A part of the diffuser flow path 14 and the scroll flow path 15 is formed by cooperation of the front housing 3a and the rear housing 3b.

The motor housing 4 has a cylindrical inner housing 4b and an outer housing 4a surrounding the inner housing 4b. The rotor 8 and the stator 9 are accommodated in the main internal space 6a on the inner side in the radial direction of the inner housing 4b. The main internal space 6a is formed by the motor housing 4, a partition wall 18 which will be described later, and a main end wall 5a which will be described later.
Between the groove formed on the outer peripheral surface of the inner housing 4b and the inner peripheral surface of the outer housing 4a, a spiral cooling passage 7a through which cooling water as a cooling fluid for cooling the stator 9 flows is formed.

  The end housing 5 has a main end wall 5a coupled to the outer housing 4a, and a sub-end wall 5b disposed behind the main end wall 5a and coupled to the main end wall 5a. The main end wall 5a and the sub end wall 5b form a sub internal space 6b in which the rotational position sensor 60 that detects the rotational position of the rotary shaft 20 and the rear side tightening portion 33 described later are accommodated. The main internal space 6a and the sub internal space 6b constitute an internal space 6. The main end wall 5a is a partition wall that partitions the main internal space 6a and the sub internal space 6b. The main end wall 5a is provided with an introduction port 5c for introducing cooling air for cooling the stator 9 into the main internal space 6a.

  An electric motor 7 that is a three-phase AC brushless motor includes a cylindrical rotor 8 that constitutes a part of a rotating shaft 20 and a stator that is disposed with a predetermined radial clearance formed radially outward of the rotor 8. 9. The rotor 8 includes a magnet 8a made of a permanent magnet as a field, and a cylindrical motor shaft 8b that is disposed so as to surround the magnet 8a and accommodates the magnet 8a. A stator 9 surrounding the rotor 8 over the entire circumference is constituted by a three-phase winding formed in a cylindrical shape having an iron core as an armature, and a terminal 7b of the three-phase winding is disposed in the outer housing 4a. Is done.

  Referring also to FIG. 2, the rotating shaft 20 includes a rotor 8 and a pair of bearing shafts 21 and 22 arranged with the rotor 8 interposed therebetween in the axial direction. Impellers 10 arranged sequentially from the front, a front bearing shaft 21 as a front shaft disposed in front of the rotor 8, a rotor 8, and a rear bearing shaft 22 as a rear shaft disposed behind the rotor 8. And the spacer in this order by the fastening member 30 including the impeller 10, the bearing shafts 21 and 22, the rotor 8, and the tension shaft 31 that passes through the center of the spacer 25 in parallel to the axial direction. The compressor 30 is combined with the fastening member 30 so as to be relatively immovable relative to each other.

  The front bearing shaft 21 and the rear bearing shaft 22 have a cylindrical cylindrical portion 21a, 22a that forms a cylindrical cylindrical space with the tension shaft 31 in the radial direction, and a diameter from the cylindrical portions 21a, 22a. And inward flange portions 21b and 22b extending inward in the direction. Each inward flange portion 21b, 22b supports the supported portions 31b1, 31d1 of the tension shaft 31 on its inner peripheral surface.

The cylindrical portion 21a of the front bearing shaft 21 is inlay-fitted on the outer periphery of the fitting portion 10b of the impeller 10 at the front end portion, and is inlay-fitted on the inner periphery of the rotor shaft 8b at the rear end portion. The cylindrical portion 22a of the rear bearing shaft 22 is inlay-fitted to the inner periphery of the rotor shaft 8b at the front end portion, and is inlay-fitted to the outer periphery of the fitting portion 25a of the spacer 25 at the rear end portion. A labyrinth seal 23 is provided on the outer peripheral surface of the front bearing shaft 21 between the rear space 17 formed behind the impeller 10 and the partition wall 18 that partitions the pressure chamber 52 in which the thrust disk 51 is housed. A labyrinth seal 24 is provided on the outer peripheral surface of the rear bearing shaft 22 between the main end wall 5a.
Here, the inlay fitting means a fitting in which the outer diameter of one fitting portion and the inner diameter of the other fitting portion are substantially equal in the fitting portion of two members that are fitted to each other.

The fastening member 30 includes a tension shaft 31, a front tightening portion 32 that is provided on the tension shaft 31, and fastens the impeller 10, the front bearing shaft 21, the rotor 8, the rear bearing shaft 21, and the spacer 25 in the axial direction. Side fastening portion 33. A front tightening portion 32 that constitutes the front end portion of the fastening member 30 and presses backward against the impeller 10 is integrally formed with the tension shaft 31. Therefore, the tension shaft 31 and the front tightening portion 32 constitute a bolt having the front tightening portion 32 as a head and the tension shaft 31 as a shaft portion. The rear tightening portion 33 is configured by a nut that is a screw member provided integrally with the tension shaft 31 by being screwed into a screw portion 31 n provided on the tension shaft 31. Therefore, the rear tightening portion 33 can be attached to and detached from the tension shaft 31.
The fastening member 30 integrates the impeller 10, the rotor 8, both bearing shafts 21 and 22, and the spacer 25 by tightening in the axial direction. The front tightening portion 32 presses the impeller 10 backward, and the rear tightening portion 33 presses the rear bearing shaft 22 forward.

  The tension shaft 31 is rearwardly arranged with an impeller insertion portion 31 a inserted into the impeller 10, a front bearing shaft insertion portion 31 b inserted into the front bearing shaft 21, and a rotor insertion portion inserted into the rotor 8. 31c, a rear bearing shaft insertion portion 31d inserted in the rear bearing shaft 22, and a rear shaft end portion 31e provided with a screw portion 31n.

The outer diameters of the impeller insertion portion 31a and the front bearing shaft insertion portion 31b are larger than the outer diameters of the rotor insertion portion 31c, the rear bearing shaft insertion portion 31d, and the rear shaft end portion 31e. The tension shaft 31 has a shape in which the outer diameter does not increase toward the rear from the front tightening portion 32, that is, a shape in which the outer diameter becomes smaller or equal.
The front bearing shaft insertion portion 31b is supported by the inward flange portion 21b at the supported portion 31b1, and the rear bearing shaft insertion portion 31d is supported by the inward flange portion 22b at the supported portion 31d1.

  Referring to FIGS. 1 and 2, the bearing device 40 disposed in the main internal space 6a includes a front radial bearing 41 (see also FIG. 2) that is a bearing that rotatably supports the front bearing shaft 21, and a rear side. And a rear radial bearing 46 that is a bearing that rotatably supports the bearing shaft 22. The radial bearings 41 and 46 are annular bearing holding plates 42 and 47, which are bearing holding members housed in the main internal space 6a, and bearing shafts 21 and 22 and a diameter on the inner peripheral surface of the bearing holding plates 42 and 47, respectively. It is comprised from the foil bearings 43 and 48 arrange | positioned facing in a direction.

The front bearing holding plate 42 is connected to the partition wall 18 by a bolt (not shown). The partition wall 18 is provided by being coupled to the front end wall 4a1 of the outer housing 4a by a bolt B2. The rear bearing holding plate 47 is provided by being coupled to the main end wall 5a by a bolt B3.
The foil bearings 43 and 48 are well-known, and the foil bearings 43 and 48 cause the rotation of the rotary shaft 20 between the front bearing shaft 21 and the foil bearing 43 and between the rear bearing shaft 22 and the foil bearing 48. In addition, an annular air film is formed so as to surround the bearing shafts 21 and 22, respectively, and the bearing shafts 21 and 22 rotate in a floating shape by the air film.

  2 and 3, the thrust canceller mechanism 50 includes a thrust disk 51 provided on the front bearing shaft 21 of the rotary shaft 20 between the impeller 10 and the rotor 8 in the axial direction, and the thrust disk 51 is accommodated. A passage forming member having a pressure chamber wall 53 that forms an annular pressure chamber 52 in cooperation with the front bearing shaft 21 and a pipe 56 that forms a pressure passage 54 that guides the pressure of the scroll passage 15 to the pressure chamber 52. And a fixed orifice 55 that is an orifice as a pressure adjusting portion provided in the pressure passage 54.

  Referring to FIG. 3, the pressure chamber wall 53 is a high pressure chamber wall 53 a that is a part of the partition wall 18, a low pressure chamber wall 53 b that is a part of the front bearing holding plate 42, and a part of the partition wall 18. It is comprised from the outer peripheral chamber wall 53c. The high-pressure chamber wall 53a and the low-pressure chamber wall 53b are axial chamber walls arranged in the pressure chamber wall 53 so as to face each other in the axial direction with the thrust disk 51 that is a movable chamber wall interposed therebetween. Therefore, the thrust disk 51 is disposed between the impeller 10 and the bearing holding plate 42 positioned in front of the rotor 8 (see FIG. 2) in the axial direction.

  A thrust disc 51 formed integrally with the front bearing shaft 21 as a flange portion having a circular outer peripheral portion includes a pressure chamber 52, a high pressure chamber 52a located on the impeller 10 side with respect to the thrust disc 51, and a rotor 8 side. And the low-pressure chamber 52b located in the axial direction. The pressurized air compressed by the impeller 10 is guided through the pressure passage 54 into the high pressure chamber 52a formed by the high pressure chamber wall 53a and the outer peripheral chamber wall 53c. On the other hand, the low pressure chamber 52b is formed by the low pressure chamber wall 53b and the outer peripheral chamber wall 53c.

Referring also to FIG. 1, the cancel thrust force Fb is generated by the differential pressure between the pressure in the high pressure chamber 52a and the pressure in the low pressure chamber 52b, and the rotating shaft 20 and the impeller 10 have the thrust force Fa and the cancel thrust force Fb. It can move in the axial direction according to its size.
In this embodiment, the cancel thrust force Fb is reduced until it substantially matches the thrust force Fa, and the thrust disk 51 is removed from the high-pressure chamber wall 53a while the electric compressor 1 is operating. The size is set such that an axial gap is formed between the high pressure chamber wall 53a and the high pressure chamber wall 53a. For this reason, the electric compressor 1 is not provided with a thrust bearing for receiving the thrust force Fa.

Further, in the radial direction, a minute radial gap is formed between the outer peripheral portion 51c of the thrust disk 51 and the outer peripheral chamber wall 53c, and the air in the high pressure chamber 52a is within a range in which a required cancel thrust force Fb can be obtained. Flows out into the low pressure chamber 52b through the radial gap.
The gas in the low-pressure chamber 52b enters the main internal space 6a as a low-pressure space having a pressure lower than that of the low-pressure chamber 52b from a minute gap between the front bearing holding plate 42 and the front end wall 4a1 or the front bearing shaft 21. leak.

The passage forming member forming the pressure passage 54 is provided with a pipe 56 connected to the rear wall 3b1 which is a part of the rear housing 3b and the outer peripheral portion of the partition wall 18, and a hole 57 constituting the pressure passage 54. Partition wall 18. The pressure passage 54 has an outlet 54a that opens to a portion closest to the rotor 8 in the axial direction in the scroll passage 15 and an outlet 54b that opens to the high-pressure chamber 52a.
The fixed orifice 55 adjusts the amount of pressurized air flowing into the pressure chamber 52 in the scroll flow path 15 so that the pressure in the high pressure chamber 52a is substantially maintained at the set value.
In the low pressure chamber 52b, a thrust foil bearing 58 capable of forming an air film between the thrust disk 51 and the thrust disk 51 is provided on the low pressure chamber wall 53b.

  As shown in FIG. 2, the impeller 10, both bearing shafts 21 and 22, the rotor 8, the partition wall 18, the front radial bearing 41, the spacer 25, the detected portion 62 of the rotational position sensor 60 and the detected portion 62 are fixed. The nut 63 which is a fixing tool to be configured constitutes a module M which is assembled in advance and integrated with each other by the fastening member 30 including the tension shaft 31 before being assembled to the housing 2.

Referring also to FIG. 1, the module M as one member is inserted from the front into the motor housing 4 before the impeller housing 3 and the end housing 5 are assembled, and the partition wall 18 is the front end wall of the outer housing 4a. 4a1 is coupled to the housing 2 by a bolt B2.
Thereafter, the main end wall 5a to which the rear radial bearing 46 is coupled is inserted into the rear bearing shaft 22 from the rear and coupled to the motor housing 4 by the bolt B4, and then the detection unit 61 of the rotational position sensor 60. Is attached to the main end wall 5a.
Thereafter, the impeller housing 3 is coupled to the front end wall 4a1 of the outer housing 4a so that the sub-end wall 5b is coupled to the main end wall 5a by the bolt B5, and then the pipe 56 is inserted into the rear wall 3b1 in an airtight manner. Thus, the electric compressor 1 is assembled.

The operation of the electric compressor 1 will be described with reference to FIGS.
A phase current controlled by an electric motor control device (not shown) is supplied to each winding of the stator 9, the electric motor 7 rotates, and the impeller 10 that is rotationally driven by the electric motor 7 sucks from the inlet channel 12. Compress the air. The compressed air compressed by the impeller 10 is supplied to the cathode side electrode through the oxidant gas supply system of the fuel cell system.
In the thrust canceller mechanism 50, a part of the pressurized air flowing through the scroll flow path 15 is supplied to the high pressure chamber 52a after the flow rate is adjusted through the pressure passage 54 and by the fixed orifice 55. As a result, a cancel thrust force Fb substantially balanced with the thrust force Fa acts on the thrust disk 51, and an axial gap is formed between the thrust disk 51 and the high-pressure chamber wall 53a. 10 is maintained at approximately the same position in the axial direction.

Next, operations and effects of the embodiment configured as described above will be described.
In the electric compressor 1, the thrust canceller mechanism 50 on which the canceling thrust force Fb that reduces the thrust force Fa acting on the rotating shaft 20 due to the rotation of the impeller 10 acts is a rotating shaft between the impeller 10 and the rotor 8. 20 and a pressure chamber wall 53 that forms a pressure chamber 52 in which the thrust disk 51 is housed. The thrust disk 51 includes a high-pressure chamber 52a that is located on the impeller 10 side. The compressed air compressed by the impeller 10 is guided into the high pressure chamber 52a through the pressure passage 54, and the cancel thrust force Fb is equal to the pressure of the high pressure chamber 52a and the low pressure. The thrust disk 51 is generated from the high pressure chamber wall 53a of the pressure chamber wall 53 by the differential pressure with respect to the pressure of the chamber 52b. It moved away in the direction of the Rusurasuto force Fb.
With this structure, the thrust disk 51 is disposed using the space between the impeller 10 and the rotor 8 of the electric motor 7 in the axial direction, and the thrust disk 51 is canceled from the pressure chamber wall 53 by the cancel thrust force Fb. By separating in the direction of the thrust force Fb, the thrust bearing is omitted and becomes unnecessary, and thus the electric compressor 1 can be downsized in the axial direction. Further, this arrangement of the thrust disk 51 allows the high-pressure chamber 52a to be positioned closer to the impeller 10 than the rotor 8 in the axial direction, so that the passage length of the pressure passage 54 that guides pressurized air to the high-pressure chamber 52a can be shortened. Therefore, the pressure loss of the pressurized air in the pressure passage 54 can be reduced. As a result, since the high pressure pressurized air can be supplied to the high pressure chamber 52a as much as the pressure loss is reduced, the thrust disk 51 can be downsized in order to obtain the required cancel thrust force Fb as compared with the case where the pressure loss is large. Therefore, the electric compressor 1 can be reduced in size and weight.

  The pressure passage 54 has a pressurized air outlet 54a at a portion closest to the rotor 8 in the axial direction in the scroll passage 15 through which the air compressed by the impeller 10 flows. It is located between the take-out port 54a and the high-pressure chamber 52a in the direction and located between the impeller 10 and the thrust disk 51 in the axial direction, so that the passage length of the pressure passage 54 is shortened. As a result, the pressure loss of the pressurized fluid in the pressure passage 54 can be reduced, and the thrust disk 51 can be downsized.

  The pressure passage 54 is provided with a fixed orifice 55 which is a pressure adjusting unit for adjusting the pressure of the pressurized air, so that the pressure of the pressurized air guided to the high pressure chamber 52a is adjusted by the fixed orifice 55. Even when the pressure of the pressurized air varies, the variation of the cancel thrust force Fb can be suppressed, and the function of the thrust canceller mechanism 50 can be stabilized.

  In the low-pressure chamber 52b, the foil bearings 43 and 48 are provided on the low-pressure chamber wall 53b that forms the low-pressure chamber 52b in the pressure chamber wall 53, so that the pressure in the high-pressure chamber 52a is temporarily increased due to the pressure fluctuation of the pressurized air. Even in the case of a high pressure, since the axial movement of the thrust disk 51 is restricted by the air film formed by the foil bearing 58, the occurrence of contact between the thrust disk 51 and the pressure chamber wall 53 can be prevented or suppressed.

  Then, by assembling the module M with the rotational balance adjusted to the motor housing 4 of the housing 2, the impeller 10, the rotor 8 of the rotary shaft 20, both bearing shafts 21, Compared with the case where the motor 22 is disassembled, the adjustment of the rotational balance after the assembly is not necessary, and the productivity of the electric compressor 1 is improved.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
As shown by a two-dot chain line in FIG. 3, a leak passage 59 that allows the air in the low pressure chamber 52 b to escape to the main internal spaces 6, 6 a, 6 b of the housing 2 is formed by a groove provided on the rear surface of the partition wall 18. Also good. The leak passage 59 is formed on the opposing surface of the partition wall 18, the front bearing holding plate 42 and the partition wall 18, and a part of the air flowing through the leak passage 59 is between the front end wall 4 a 1 and the front bearing holding plate 42. It flows out to the main internal space 6a through the gap, and the remaining part flows out to the main internal space 6a between the rear housing 3b and the front end wall 4a1.
According to this structure, according to this, since the gas in the low pressure chamber 52b flows out through the leak passage 59, it becomes easy to lower the pressure in the low pressure chamber 52b, and the cancel thrust force having a magnitude that reduces the thrust force Fa. Formation of Fb is facilitated.

The thrust foil bearing 58 disposed in the low-pressure chamber 52b is provided on the low-pressure chamber wall 53b. Instead of the low-pressure chamber wall 53b, the thrust disk 51 has a side facing the low-pressure chamber wall 53b in the axial direction. Or may be provided on both the low-pressure chamber wall 53b and the thrust disk 51. Also in this case, the same effect as that of the above-described embodiment is achieved.
The electric compressor 1 includes a control device including a pressure sensor that detects the pressure of the high-pressure chamber 52a, and a control unit that controls an actuator that adjusts the diameter of the orifice based on the pressure detected by the pressure sensor. The adjustment unit may be configured by a variable orifice whose diameter is adjusted by the actuator.
Although the cancellation thrust force Fb decreases the thrust force Fa, it may be smaller than the thrust force. In this case, in the high-pressure chamber 52a, a foil bearing is provided at a portion of at least one of the high-pressure chamber wall 53a and the thrust disk 51 facing each other in the axial direction, and the thrust canceller mechanism 50 also serves as the thrust bearing. .
The fuel cell system may be used other than a vehicle, for example, a general-purpose one. Moreover, the electric compressor 1 may be used for apparatuses other than a fuel cell system, and may compress gas other than air.
The electric compressor may be an axial compressor that includes an axial impeller.

DESCRIPTION OF SYMBOLS 1 Electric compressor 2 Housing 7 Motor 8 Rotor 10 Impeller 15 Scroll flow path 20 Rotating shafts 21 and 22 Bearing shaft 30 Fastening member 31 Tension shaft 50 Thrust canceller mechanism 51 Thrust disk 52 Pressure chamber 54 Pressure passage 55 Fixed orifice Fa Thrust force Fb Cancel thrust force

Claims (5)

A housing that rotatably supports a rotating shaft that is rotationally driven by a rotor of an electric motor, an impeller that rotates integrally with the rotating shaft, and a cancel that reduces a thrust force that acts on the rotating shaft due to the rotation of the impeller In an electric compressor provided with a thrust canceller mechanism on which a thrust force acts,
The thrust canceller mechanism includes a thrust disk provided on the rotating shaft between the impeller and the rotor in the axial direction, and a pressure chamber wall forming a pressure chamber in which the thrust disk is housed.
The thrust disk divides the pressure chamber into an axial direction, a high pressure chamber located on the impeller side and a low pressure chamber located on the rotor side,
In the high-pressure chamber, the pressurized gas compressed by the impeller is guided through a pressure passage,
The electric compressor according to claim 1, wherein the cancel thrust force is generated by a differential pressure between a pressure in the high pressure chamber and a pressure in the low pressure chamber. The electric compressor according to claim 1,
In the scroll flow path through which the pressurized fluid flows, the pressure passage has an outlet for the pressurized fluid in a portion closest to the rotor in the axial direction,
The electric compressor is characterized in that the entirety of the pressure passage is located between the outlet and the high pressure chamber in the radial direction and located between the impeller and the thrust disk in the axial direction. The electric compressor according to claim 1 or 2,
The electric compressor, wherein the pressure passage is provided with a pressure adjusting unit that adjusts the pressure of the pressurized gas. The electric compressor according to any one of claims 1 to 3,
In the low pressure chamber, a foil bearing is provided on a low pressure chamber wall forming the low pressure chamber in the pressure chamber wall or on the thrust disk facing the low pressure chamber wall in the axial direction. Machine. The electric compressor according to any one of claims 1 to 4,
An electric compressor characterized in that a leak passage is provided for escaping gas in the low-pressure chamber.

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