JP5200871B2 - Electric roots type pump - Google Patents

Description

  The present invention relates to an electric roots type pump.

For example, an electric roots pump used to supply hydrogen gas to a fuel cell has a driven shaft driven by an electric motor and a driven shaft that is gear-coupled to rotate a rotor attached to each shaft in a rotor chamber. Thus, the hydrogen gas sucked into the rotor chamber is discharged outside the rotor chamber and supplied to the fuel cell. In addition, in the electric roots type pump, by providing a coating film made of a resin material at a predetermined portion of the rotor, when the rotors interfere with each other, the coating film is scraped by the amount of interference so that the clearance between the rotors is properly It is made to adjust (for example, patent document 1).
Japanese Patent Laid-Open No. 2002-213381

  However, in an electric roots type pump, for example, when operated at a high speed, the motor rotor rotates at a high speed in the stator of the electric motor, so that the electric motor generates heat due to iron loss generated in the stator, and the temperature of the electric motor is increased. To rise. Then, due to the temperature rise of the electric motor, the magnetic force generated from the permanent magnet provided in the motor rotor is reduced, and the torque of the electric motor is reduced. The heat generated by the electric motor is transmitted to the drive rotor through the drive shaft and radiated from the drive rotor. However, as in Patent Document 1, the rotor is provided with a coating film. In Patent Document 1, a coating film is provided on each of the regions on the rotational direction side where the rotor rotates on the side surfaces of both rotors. For this reason, in the electric roots type pump provided with the rotor of patent documents 1, there was a problem that heat dissipation of a rotor was bad and heat dissipation of an electric motor was bad.

  An object of the present invention is to provide an electric roots type pump that can efficiently dissipate heat of a drive rotor and can improve heat dissipation of an electric motor.

  In order to achieve the above object, according to the first aspect of the present invention, a drive shaft driven by an electric motor and a driven shaft geared to the drive shaft are supported by a housing, and the drive shaft and the driven shaft are supported. A metal drive rotor and a driven rotor having hook teeth and valley teeth that can mesh with each other are attached to the shaft, and a rotor chamber in which the drive rotor and the driven rotor are accommodated is formed in the housing. An electric roots pump that discharges the fluid sucked into the rotor chamber by the rotation of the drive rotor and the driven rotor, wherein the driven rotor is orthogonal to the axial direction of the driven shaft, and the rotor chamber An end surface coating film is provided on a pair of end surfaces facing the inner peripheral surface of the rotor, and in the driven rotor, the entire side surface connecting the pair of end surfaces is provided on the side surface. In the drive rotor, an end face coating film is provided on a pair of end surfaces orthogonal to the axial direction of the drive shaft and opposed to the inner peripheral surface of the rotor chamber. The top end of the chevron on the side surface connecting the pair of end surfaces is provided with a top end coating film that connects the end surface coating films, and the side surface of the drive rotor is a metal surface in a region excluding the top end coating film. The gist is that is exposed.

  According to the present invention, the end face coating film and the top end coating film are provided only on the pair of end faces and the top ends of the chevron in the drive rotor. Therefore, on the side surface of the drive rotor, since the top end coating film is provided only on the top end of the chevron, the metal surface can be exposed in the region on the rotational direction side of the drive rotor. Therefore, heat generated in the electric motor and transmitted to the drive rotor via the drive shaft can be efficiently radiated from the metal surface of the drive rotor to the fluid in the rotor chamber, and the heat dissipation of the electric motor can be improved. Can do.

According to a second aspect of the present invention, a drive shaft driven by an electric motor and a driven shaft geared to the drive shaft are supported by a housing, and the drive shaft and the driven shaft are meshed with each other. A metal drive rotor and driven rotor having teeth and valley teeth are attached, and a rotor chamber in which the drive rotor and the driven rotor are accommodated is formed in the housing, and the drive rotor and the driven rotor are formed. An electric roots-type pump that discharges fluid sucked into the rotor chamber by rotation of the rotor, wherein the pair of driven rotors is orthogonal to the axial direction of the driven shaft and faces the inner peripheral surface of the rotor chamber. An end face coating film is provided on the end face of the rotor, and a side coating film is provided on the entire side face connecting the pair of end faces in the driven rotor. Furthermore, in the drive rotor, an end surface coating film is provided on a pair of end surfaces orthogonal to the axial direction of the drive shaft and facing the inner peripheral surface of the rotor chamber, and in the drive rotor, the pair of end surfaces A top end coating film that connects the end surface coating films is provided on the top end of the chevron on the side surface that connects the two sides, and the side surface of the drive rotor is edged over the entire circumference of the pair of end surfaces of the drive rotor. A partial coating film is provided , and the gist is that a metal surface is exposed on a side surface of the drive rotor excluding the top end coating film and the edge coating film .

  According to the present invention, since the end surface coating film of the drive rotor is provided continuously with the edge coating film, the end surface coating film is peeled off by interference with the inner peripheral surface of the rotor chamber when the drive rotor rotates. Can be prevented.

  According to this invention, the heat of the drive rotor can be efficiently radiated, and the heat dissipation of the electric motor can be improved.

  Hereinafter, an embodiment in which the present invention is embodied in an electric roots pump will be described with reference to FIGS. 1 and 2. In addition, the electric roots type pump in this embodiment is used in order to supply again hydrogen gas (what is called hydrogen offgas) as a fluid which was not used with the fuel cell to a fuel cell.

  As shown in FIG. 1, the housing of the electric roots type pump 10 (hereinafter simply referred to as “pump 10”) includes a gear housing G joined and fixed to the rotor housing 12, and a motor housing 17 attached to the gear housing G. Joined and fixed. The rotor housing 12 has a first housing 13 and a second housing 14. The first housing 13 has a bottomed cylindrical shape, and includes a cylindrical peripheral wall 13 a and an end wall 13 b that forms the bottom of the first housing 13.

  A rotor chamber 15 is formed from the peripheral wall 13 a, the end wall 13 b, and the second housing 14 by joining and fixing the second housing 14 to the opening side of the peripheral wall 13 a in the housing. The inner peripheral surface of the rotor chamber 15 is configured by an inner peripheral surface 131 a of the peripheral wall 13 a, an inner surface 131 b of the end wall 13 b, and an end surface 14 a of the second housing 14. Further, a gear chamber 16 is formed in the housing by joining and fixing the gear housing G and the second housing 14. Further, a motor chamber 18 is formed in the housing by joining and fixing the motor housing 17 and the gear housing G. An electric motor 19 is accommodated in the motor chamber 18.

  The electric motor 19 includes a stator 19b fixed to the inner surface of the motor housing 17, and a motor rotor 19a disposed inside the stator 19b and relatively rotatable in both forward and reverse directions with respect to the stator 19b. The stator 19b has a stator coil 192b, and the stator coil 192b is electrically connected to an external power source (not shown) through a plurality of lead wires (not shown). The motor rotor 19a is formed in a cylindrical shape, and a drive shaft 21 is fastened inside the motor rotor 19a. The drive shaft 21 can rotate integrally with the motor rotor 19a. The motor rotor 19a includes a rotor core 191a fixed to the drive shaft 21 and a plurality of permanent magnets 192a provided on the peripheral surface of the rotor core 191a. In the housing, the drive shaft 21 is cantilevered and supported by the second housing 14, the motor housing 17 and the gear housing G via a bearing 23.

  The peripheral wall 13 a of the first housing 13 is formed with a suction port 31 for sucking the hydrogen off gas into the rotor chamber 15 and a discharge port 32 for discharging the sucked hydrogen off gas to the outside of the rotor chamber 15. A pipe (not shown) is provided outside the rotor chamber 15 and between the discharge port 32 and the hydrogen off-gas supply destination (fuel cell), and a throttle (not shown) is provided in the pipe. ing. The hydrogen off-gas discharged from the discharge port 32 is externally compressed by the throttle.

  The pump 10 is provided with a driven shaft 22 parallel to the drive shaft 21. The driven shaft 22 is cantilevered on the second housing 14 of the rotor housing 12 via a bearing 23 so as to be rotatable. In the gear chamber 16, a drive gear 26 fixed to the drive shaft 21 and a driven gear 25 fixed to the driven shaft 22 are accommodated in an engaged state. The drive shaft 21 and the driven shaft 22 are gear-connected by a drive gear 26 and a driven gear 25.

  As shown in FIG. 2, a metal drive rotor 27 housed in the rotor chamber 15 is attached and fixed to the drive shaft 21, and a metal follower housed in the rotor chamber 15 is attached to the driven shaft 22. The rotor 28 is fixedly attached. The drive rotor 27 and the driven rotor 28 are formed in a two-leaf shape (saddle shape) in a cross-sectional view orthogonal to the axial directions of the drive shaft 21 and the driven shaft 22. Two ridges 27a are formed on the drive rotor 27, and valley teeth 27b are formed between the two ridges 27a. Further, the driven rotor 28 is formed with two ridges 28a, and valley teeth 28b are formed between the ridges 28a. The drive rotor 27 and the driven rotor 28 are accommodated in the rotor chamber 15 in a state where the tooth teeth 27a and 28a and the valley teeth 27b and 28b of the rotors 27 and 28 can mesh with each other.

  As shown in FIG. 1, in the drive rotor 27, a concave portion 27d is formed on one end surface 27c that is orthogonal to the axial direction of the drive shaft 21 and faces the inner surface 131b of the end wall 13b. In the drive rotor 27, an end face that is orthogonal to the axial direction of the drive shaft 21 and faces the end face 14a of the second housing 14 is referred to as the other end face 27f. Further, in the drive rotor 27, a drive rotor inner passage 27 e is formed on each side of the both teeth 27 a that communicate with the recess 27 d and sandwich the drive shaft 21. Each drive rotor inner passage 27e is formed along the axial direction of the drive shaft 21 so as to extend from the recess 27d to the other end surface 27f of the drive rotor 27.

  In the driven rotor 28, a concave portion 28d is formed on one end surface 28c orthogonal to the axial direction of the driven shaft 22 and facing the inner surface 131b of the end wall 13b. In the driven rotor 28, an end surface orthogonal to the axial direction of the driven shaft 22 and facing the end surface 14 a of the second housing 14 is defined as the other end surface 28 f. As shown in FIG. 2, in the driven rotor 28, a driven rotor internal passage 28 e is formed on each side of the both teeth 28 a that communicate with the recess 28 d and sandwich the driven shaft 22. Each driven rotor inner passage 28e is formed along the axial direction of the driven shaft 22 so as to extend from the recess 28d to the other end face 28f of the driven rotor 28.

  Next, coating on the drive rotor 27 and the driven rotor 28 will be described with reference to FIG. In FIG. 2, regions where the coating film is provided on the driving rotor 27 and the driven rotor 28 are indicated by hatching. FIG. 2 is a partial perspective view of the pump 10 as viewed from the end wall 13 b side of the first housing 13.

  As shown in FIG. 2, a resin-made end face coating film 40a is provided on one end face 28c and the other end face 28f of the driven rotor 28. An end face coating film 40a provided on the other end face 28f of the driven rotor 28 is shown in an enlarged manner in FIG. Further, a side coating film 40b made of resin is provided over the entire side surface connecting both end surfaces 28c, 28f of the driven rotor 28. That is, the entire outer peripheral surface of the driven rotor 28 is coated.

  A resin end face coating film 41a is provided on the entire surface of one end face 27c and the other end face 27f of the drive rotor 27. An end surface coating film 41a provided on the other end surface 27f of the drive rotor 27 is shown in an enlarged manner in FIG. Further, a resin-made top end coating film 41b is connected to the both end surfaces 27c, 27f of the drive rotor 27 at a position where the top ends 27g of both mountain teeth 27a are connected to each other so as to connect both end surface coating films 41a of the drive rotor 27. Is provided. Note that the top end 27g of the drive rotor 27 is a portion that faces the inner peripheral surface 131a of the peripheral wall 13a so as to maintain a minimum clearance when the drive rotor 27 rotates. A metal surface 27h is exposed on the entire side surface of the drive rotor 27 where the top end coating film 41b is not provided. That is, the metal surface 27h is exposed on the side surface of the drive rotor 27 and in the region excluding the top end coating film 41b in the region that interferes with the side surface coating film 40b of the driven rotor 28.

  In the pump 10 configured as described above, when electric power is supplied to the stator 19b of the electric motor 19, the motor rotor 19a rotates and the drive shaft 21 rotates. Then, the driven shaft 22 rotates in a direction different from the drive shaft 21 through the meshing connection of the drive gear 26 and the driven gear 25, and the drive rotor 27 and the driven rotor 28 also rotate. That is, the drive rotor 27 rotates in the direction indicated by the arrow Y1 shown in FIG. 2 (counterclockwise), and the driven rotor 28 rotates in the direction indicated by the arrow Y2 shown in FIG. 2 (clockwise).

  Then, the hydrogen off-gas that has not been used in the fuel cell is sucked into the rotor chamber 15 from the suction port 31 through a conduit (not shown) with the synchronous rotation of the drive rotor 27 and the driven rotor 28. The hydrogen off gas sucked into the rotor chamber 15 from the suction port 31 is discharged out of the rotor chamber 15 from the discharge port 32. The hydrogen off gas discharged from the discharge port 32 is supplied again to the fuel cell via a pipe line (not shown). Note that the hydrogen off-gas includes generated water generated with the power generation of the fuel cell.

  In the pump 10, end face coating films 40 a and 41 a are provided on both end faces 28 c and 28 f of the driven rotor 28 and both end faces 27 c and 27 f of the drive rotor 27. Therefore, when the driven rotor 28 and the drive rotor 27 are rotated, the inner surface 131b of the end wall 13b and the end surface 14a of the second housing 14, the both end surfaces 28c and 28f of the driven rotor, and both end surfaces 27c and 27f of the drive rotor 27 are formed. When they interfere with each other, the end surface coating films 40a and 41a are cut by the amount of interference, and the clearance is adjusted appropriately. Further, since the side surface coating film 40 b is provided over the entire side surface of the driven rotor 28, the metal surface 27 h of the drive rotor 27 and the side surface coating film of the driven rotor 28 are rotated when the driven rotor 28 and the drive rotor 27 are rotated. If they interfere with each other, the side coating film 40b is scraped by the amount of interference, and the clearance is adjusted appropriately. Further, when the metal surface 27h of the drive rotor 27 meshes with the side surface of the driven rotor 28, the side surface coating film 40b prevents the metal surface 27h of the drive rotor 27 from being seized. Further, since the top end coating film 41b is provided on the top end 27g of the drive rotor 27, when the drive rotor 27 rotates, the top end coating film 41b of the drive rotor 27 and the inner peripheral surface 131a of the peripheral wall 13a interfere with each other. The top end coating film 41b is cut by the amount of interference, and the clearance is adjusted appropriately.

  When the pump 10 is operated at a high speed, the motor rotor 19a rotates at a high speed in the stator 19b, so that the electric motor 19 generates heat due to iron loss generated in the motor rotor 19a. The heat generated by the electric motor 19 is transmitted to the drive shaft 21 fastened inside the motor rotor 19a, and is further transmitted to the drive rotor 27 attached and fixed to the drive shaft 21. Here, the drive rotor 27 is provided with the end face coating film 41 a and the top end coating film 41 b only on both end faces 27 c and 27 f of the drive rotor 27 and the top end 27 g of the drive rotor 27. In this region, the coating is not applied and the metal surface 27h is exposed. For this reason, the hydrogen off-gas sucked into the rotor chamber 15 from the suction port 31 can be brought into contact with the metal surface 27h. Therefore, the heat transmitted from the electric motor 19 to the drive rotor 27 can be radiated to the hydrogen off gas (particularly, the generated water contained in the hydrogen off gas).

In the above embodiment, the following effects can be obtained.
(1) In the drive rotor 27, end face coating films 41a are provided on the entire surfaces of both end faces 27c and 27f of the drive rotor 27. A top end coating film 41 b is provided on the top end 27 g of the drive rotor 27. Therefore, on the side surface of the drive rotor 27, the top end coating film 41b is provided only on the top end 27g of the tooth 27a, and the other surface is not coated and the metal surface 27h is exposed. Therefore, the hydrogen off gas sucked into the rotor chamber 15 from the suction port 31 can be brought into contact with the metal surface 27h. Therefore, the heat generated by the electric motor 19 and transmitted to the drive rotor 27 via the drive shaft 21 can be efficiently radiated from the metal surface 27h of the drive rotor 27 to the hydrogen off-gas. Can be improved. As a result, when heat is generated in the electric motor 19, the magnetic force generated from the permanent magnet 192a provided in the motor rotor 19a is reduced due to the temperature rise of the electric motor 19, and the torque of the electric motor 19 is reduced. Can be suppressed.

  (2) In the drive rotor 27, end face coating films 41a are provided on the entire surfaces of both end faces 27c and 27f of the drive rotor 27 that interfere with the inner surface 131b of the end wall 13b and the end face 14a of the second housing 14. Further, a top end coating film 41b is provided on the top end 27g of the drive rotor 27 that interferes with the inner peripheral surface 131a of the peripheral wall 13a. Further, in the driven rotor 28, end face coating films 40 a are provided on the entire surfaces of both end faces 28 c and 28 f of the driven rotor 28 that interfere with the inner surface 131 b of the end wall 13 b and the end face 14 a of the second housing 14. A side coating film 40b is provided on the entire side surface of the driven rotor 28 over the entire circumference. Therefore, in order to prevent clearance adjustment and seizure between the drive rotor 27 and the driven rotor 28 and the inner peripheral surface of the rotor chamber 15, it is not necessary to coat the entire inner peripheral surface of the rotor chamber 15. The processing process of the housing becomes easy.

  (3) While the end face coating film 40a and the side face coating film 40b are provided on both end faces 28c, 28f and the entire side face of the driven rotor 28, only the end faces 27c, 27f of the drive rotor 27 and the top ends 27g of the both teeth 27a A coating film 41a and a top end coating film 41b were provided. For this reason, the heat from the electric motor 19 is directly transmitted through the drive shaft 21, and the heat dissipation of the drive rotor 27, which is likely to be higher than the driven rotor 28, can be improved compared to the driven rotor 28.

  (4) On the side surface of the drive rotor 27, the metal surface 27h is exposed in the entire region other than the top ends 27g of the both mountain teeth 27a. Therefore, the heat dissipation of the drive rotor 27 can be improved by positively exposing the metal surface 27h on the side surface of the drive rotor 27.

  (5) The pump 10 of the present embodiment is used to supply again to the fuel cell hydrogen off-gas that has not been used in the fuel cell. The hydrogen off-gas is generated by the power generation of the fuel cell. Contains water. Therefore, the heat generated by the electric motor 19 and transmitted to the drive rotor 27 via the drive shaft 21 is more efficient than when the fluid that does not contain generated water and the metal surface 27h of the drive rotor 27 are in contact with each other. It can dissipate heat well.

In addition, you may change the said embodiment as follows.
In the embodiment, as shown in FIG. 3, on the side surface of the drive rotor 27, the edge coating is performed over the entire circumference of the edge on the one end surface 27 c side of the drive rotor 27 and the edge on the other end surface 27 f side. Films 41c and 41d may be provided. The edge coating films 41c and 41d are provided to the drive rotor 27 continuously with the end face coating film 41a. According to this, since the end surface coating film 41a is provided continuously with the edge coating films 41c and 41d, the end surface coating film 41a is formed on the inner surface 131b of the end wall 13b and the second housing when the drive rotor 27 rotates. It is possible to prevent peeling due to interference with the end face 14a of the fourteen.

  In the embodiment, the pump 10 is used to supply again the hydrogen off gas that has not been used in the fuel cell to the fuel cell. However, the pump 10 is not limited thereto, and for example, for transferring another fluid other than the hydrogen off gas. The pump 10 may be used, or the pump 10 may be used as a refrigerant compression compressor in an air conditioner.

The present invention may be embodied in an electric roots type pump having a drive rotor 27 and a driven rotor 28 having a trilobal shape or more.
The present invention may be embodied in a multistage electric roots pump in which a plurality of drive rotors 27 and driven rotors 28 are attached and fixed in the axial direction of the drive shaft 21 and the driven shaft 22.

The following technical idea (invention) can be understood from the embodiment.
(1) The electric roots-type pump according to claim 1 or 2, wherein the drive rotor and the driven rotor have a two-leaf shape.

The plane sectional view of the electric roots type pump in an embodiment. The partial expansion perspective view in a rotor chamber. The partial expansion perspective view in the rotor chamber in another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric roots type pump, 12 ... Rotor housing as a housing, 131a ... Inner peripheral surface of the peripheral wall which comprises the inner peripheral surface of a rotor chamber, 131b ... Inner surface of the end wall which comprises the inner peripheral surface of a rotor chamber, 14a ... End surface of the second housing constituting the inner peripheral surface of the rotor chamber, 15 ... rotor chamber, 17 ... motor housing as a housing, 19 ... electric motor, 21 ... drive shaft, 22 ... driven shaft, 27 ... drive rotor, 27a ... Mountain tooth, 27b ... Valley tooth, 27c, 27f ... End face, 27g ... Top end, 27h ... Metal face, 28 ... Driven rotor, 28a ... Mountain tooth, 28b ... Valley tooth, 28c, 28f ... End face, 40a, 41a ... End face coating Membrane, 40b ... side coating membrane, 41b ... top end coating membrane, 41c, 41d ... edge coating membrane, G ... gear housing as housing.

Claims (2)

A drive shaft driven by an electric motor and a driven shaft geared to the drive shaft are pivotally supported by the housing, and the drive shaft and the driven shaft have metal teeth that are meshed with each other. The drive rotor and the driven rotor are attached, and the housing is formed with a rotor chamber in which the drive rotor and the driven rotor are accommodated, and the rotor chamber is accommodated by rotation of the drive rotor and the driven rotor. An electric roots type pump that discharges the sucked fluid,
In the driven rotor, an end surface coating film is provided on a pair of end surfaces orthogonal to the axial direction of the driven shaft and opposed to the inner peripheral surface of the rotor chamber, and the pair of end surfaces are connected in the driven rotor. A side coating film is provided on the entire side surface,
Furthermore, in the drive rotor, an end surface coating film is provided on a pair of end surfaces orthogonal to the axial direction of the drive shaft and facing the inner peripheral surface of the rotor chamber, and in the drive rotor, the pair of end surfaces A top end coating film that connects the end face coating films to each other is provided at the top end of the chevron on the side surface connecting
An electric roots-type pump, characterized in that a metal surface is exposed on a side surface of the drive rotor excluding the top end coating film. A drive shaft driven by an electric motor and a driven shaft geared to the drive shaft are pivotally supported by the housing, and the drive shaft and the driven shaft have metal teeth that are meshed with each other. The drive rotor and the driven rotor are attached, and the housing is formed with a rotor chamber in which the drive rotor and the driven rotor are accommodated, and the rotor chamber is accommodated by rotation of the drive rotor and the driven rotor. An electric roots type pump that discharges the sucked fluid,
In the driven rotor, an end surface coating film is provided on a pair of end surfaces orthogonal to the axial direction of the driven shaft and opposed to the inner peripheral surface of the rotor chamber, and the pair of end surfaces are connected in the driven rotor. A side coating film is provided on the entire side surface,
Furthermore, in the drive rotor, an end surface coating film is provided on a pair of end surfaces orthogonal to the axial direction of the drive shaft and facing the inner peripheral surface of the rotor chamber, and in the drive rotor, the pair of end surfaces A top end coating film that connects the end surface coating films is provided on the top end of the chevron on the side surface that connects the two sides, and the side surface of the drive rotor is edged over the entire circumference of the pair of end surfaces of the drive rotor. Part coating film is provided ,
An electric roots pump characterized in that a metal surface is exposed on a side surface of the drive rotor except for the top end coating film and the edge coating film .

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