JP2007138820A - Electric pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric pump capable of preventing drop of insulating performance by preventing metal powder from being precipitated in a wiring hole. <P>SOLUTION: A connection flange 14 for connecting a housing to a tank is provided on the housing of the electric pump P. The wiring hole 14a through which a lead wire L electrically connected to an electric motor M in the housing paths is formed on the connection flange 14, and power source terminals 27, 28 for the motor connected to the external power source are provided in the wiring hole 14a. The lead wire L is electrically connected to the power source terminals 27, 28 for the motor, and the lead wire L is arranged to extend in a spiral shape along a rotation direction of a drive shaft 21 toward the power source terminals 27, 28 for the motor from the electric motor M. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric pump that is installed in a tank that stores liquid and that pumps the liquid in the tank to the outside of the tank.

  This type of electric pump is incorporated in, for example, a fuel supply system, and includes an electric pump in an in-tank pump disclosed in Patent Document 1. This electric pump is installed in a tank that stores dimethyl ether (DME) as fuel, and pumps the DME out of the tank. The remaining DME that could not be consumed outside the tank returns to the tank again. The electric pump is suspended from a lower surface of a connection flange fixed to the upper wall of the tank, and the housing of the electric pump is connected to a motor housing disposed below the connection flange. It is constituted by joining.

An electric motor is accommodated in the motor chamber of the motor housing, and a pump portion (gear pump) is accommodated in the pump chamber of the pump housing. The connection flange is formed with a wiring hole that penetrates the connection flange in the thickness direction (vertical direction) and communicates with the motor chamber, and a blocking body is fitted in the wiring hole. A plurality of terminals are fixed to the blocking body in a state of penetrating the blocking body. The lower end of the terminal located in the wiring hole is electrically connected to the upper end of a lead wire drawn into the wiring hole, and the lower end of the lead wire is electrically connected to a stator coil in the electric motor. Has been. The upper end of the terminal is connected to an external power source. And by energizing the stator coil, a rotational force is generated in the rotor of the electric motor, and the rotational shaft is rotated by this rotational force. When the rotating shaft rotates, the pump unit is driven, and the DME in the tank becomes a high pressure by driving the pump unit and is pumped to the supply destination.
JP 2005-201237 A

  By the way, in the electric pump, metal powder (wear powder) is generated in the electric pump due to wear caused by driving of the pump portion (sliding contact between gears), wear of a bearing supporting the rotating shaft, and the like. In addition, the metal powder adhered to the tank and the pipe connected to the tank, and the trace amount of metal powder existing in the fuel supply system circulates in the fuel supply system together with the flow of DME. Flows into the housing of the electric pump. Here, since the inside of the housing is filled with DME, the metal powder generated in the electric pump and the metal powder flowing into the housing together with DME are floating in the DME filled in the housing.

  The electric pump may be used with a connection flange connected to the bottom of the tank. That is, a motor housing and a pump housing are disposed above the connection flange, and an electric pump is used. At this time, since the upper opening of the wiring hole of the connection flange opens toward the inside of the housing (motor chamber), the wiring hole communicates with the inside of the housing (motor chamber), and the blocking body is the bottom of the wiring hole. Is forming. For this reason, the metal powder generated in the housing of the electric pump or the metal powder flowing into the housing may enter the wiring hole and further settle on the blocking body. As a result, the metal powder becomes a conductor between the terminal, the blocking body, and the connection flange, and there is a possibility that the insulation in the electric pump is lowered.

  An object of the present invention is to provide an electric pump capable of preventing metal powder from being precipitated in a wiring hole and preventing a decrease in insulation.

  In order to solve the above problems, the invention according to claim 1 is an electric pump that is installed in a tank that stores liquid and that pumps the liquid in the tank to the outside of the tank. A pump section for pumping liquid is housed, and a motor chamber is formed for housing an electric motor for rotating the rotating shaft to drive the pump section. Further, the housing is connected to the tank. A connection flange is provided, and the connection flange is formed with a wiring hole through which a lead wire electrically connected to the electric motor is formed in the housing. The liquid is substantially filled, and a blocking body for blocking the inside of the housing from the outside is mounted in the wiring hole, and the blocking body is connected to an external power source. The motor power terminal is provided, and the lead wire is electrically connected to the motor power terminal, and the lead wire rotates from the electric motor toward the motor power terminal. Are arranged so as to extend in a spiral shape.

  According to this configuration, a flow is generated in the liquid in the motor chamber by the rotation of the rotation shaft inside the housing. Here, since the lead wire extends from the electric motor side to the motor power supply terminal side and the motor power supply terminal is provided in the wiring hole, the lead wire is drawn into the wiring hole and is generated in the motor chamber. The liquid flow thus transmitted is transmitted into the wiring hole by the lead wire. For this reason, the liquid is prevented from flowing in the wiring hole, and the liquid is prevented from staying in the wiring hole. Therefore, even if metal powder enters the wiring hole, the inside of the wiring hole is agitated by the flow of liquid in the wiring hole, and the metal powder can flow out of the wiring hole, and the metal powder precipitates in the wiring hole. Can be prevented. Even if the metal powder settles in the wiring hole while the electric pump is stopped, when the electric pump is operated again, the precipitated metal powder is removed out of the wiring hole by stirring in the wiring hole due to the flow of liquid. During the operation of the electric pump, it is possible to prevent the metal powder from being precipitated in the wiring hole.

  In addition, the electric pump is inserted into the tank from the bottom wall side of the tank, and the connection flange is connected to the bottom wall of the tank and is used above the wiring hole in the housing. The motor chamber may be disposed, the wiring hole may open toward the motor chamber, and the blocking body may constitute the bottom of the wiring hole.

  According to this configuration, even if the electric pump is used in a state where the wiring hole is open toward the motor chamber and the metal powder easily enters the wiring hole, the flow of liquid in the wiring hole It is possible to make it difficult for the metal powder to enter the metal, and it is possible to flow the metal powder out of the wiring hole. Therefore, the configuration in which the liquid flow is generated in the wiring hole using the lead wire is effective when the electric pump is installed and used on the bottom wall side of the tank.

Further, the blocking body may be located below the opening on the motor chamber side of the wiring hole.
According to this configuration, a large amount of metal powder may be deposited on the blocking body in the wiring hole. However, by generating a liquid flow in the wiring hole by the lead wire, it is possible to make it difficult for the metal powder to enter the wiring hole, and to flow the metal powder out of the wiring hole. Therefore, the configuration in which the liquid flow is generated in the wiring hole using the lead wire is particularly effective when used in a configuration in which the blocking body is positioned below the opening on the motor chamber side of the wiring hole. .

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that metal powder precipitates in a wiring hole, and can prevent that insulation falls.

  Hereinafter, an embodiment in which the present invention is embodied in an electric pump P used in a fuel supply device S of an engine (internal combustion engine) will be described with reference to FIGS. In the following description, “upper” and “lower” mean the direction of gravity when the tank T in the fuel supply device S is in use. The direction indicated by the arrow Y in FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2, but is a schematic cross-sectional view mainly illustrating the wiring hole 14a and the insertion hole 15a.

  FIG. 1 is a schematic configuration diagram showing the fuel supply device S. As shown in FIG. The fuel supply device S includes a tank T in which DME (dimethyl ether) as a liquid is stored, and an electric pump P that is installed in the tank T and pumps the DME from the inside of the tank T to the outside of the tank T. ing. An injection pump 12 is connected to the electric pump P of the fuel supply device S via a discharge pipe 11, and an engine 13 is connected to the injection pump 12. The injection pump 12 is configured to inject and supply the DME pumped from the electric pump P to the engine 13 in a high pressure state.

  Next, the electric pump P will be described. As shown in FIG. 2, the electric pump P has a metal connection flange 14, a metal pump housing 15 joined to the upper end surface of the connection flange 14, and an upper end surface of the pump housing 15. The metal motor housing 16 is configured to be tightened and coupled with a plurality of through bolts B (only one through bolt B is shown in FIG. 2). That is, the housing of the electric pump P is configured by joining the connecting flange 14, the pump housing 15, and the motor housing 16 in the same order. The electric pump P is installed in the tank T by inserting the motor housing 16 side into the tank T from the bottom wall Ta side of the tank T and fixing the connection flange 14 to the bottom wall Ta with the bolt 10. ing.

  A wiring hole 14 a is formed in the connection flange 14 so as to penetrate the connection flange 14 in the thickness direction (vertical direction). A metal blocking body 25 having a covered cylindrical shape is fitted (attached) to the lower side of the wiring hole 14a. The blocking body 25 is connected to the wiring hole 14a by a circlip C fitted to the peripheral surface of the wiring hole 14a. Is positioned inside. Further, a seal member 26 made of a rubber O-ring is interposed between the outer peripheral surface of the blocking body 25 and the peripheral surface of the wiring hole 14a, and the sealing member 26 allows the wiring hole 14a and the blocking body 25 to be connected. DME leakage from the gap is suppressed, and the inside of the housing is blocked from the outside by the blocking body 25. The blocking body 25 is positioned below the opening 14b on the upper surface side (motor chamber 18 side) of the connection flange 14 in the wiring hole 14a, and constitutes the bottom of the wiring hole 14a. That is, the connection flange 14 is provided with a recess F that opens into the housing by the wiring hole 14a and the blocking body 25, and the opening 14b constitutes the opening of the recess F.

  A plurality (two in this embodiment) of motor power terminals 27 and 28 are fixed to the blocking body 25 so as to penetrate the blocking body 25 in the vertical direction. The upper ends of the motor power terminals 27 and 28 are disposed in the wiring hole 14a (in the recess F), while the lower ends of the motor power terminals 27 and 28 protrude out of the electric pump P, and are connected to an external power source (see FIG. (Not shown). The motor power terminals 27 and 28 are fixed to the blocking body 25 by glass as an insulator, and the motor power terminals 27 and 28 and the blocking body 25 are electrically insulated by the glass.

  In the housing of the electric pump P, a drive shaft 21 as a rotating shaft extending in the vertical direction of the electric pump P is disposed, and the upper end of the drive shaft 21 is rotated by a bearing 22 disposed in the motor housing 16. The lower end is rotatably supported by a bearing 23 disposed on the connection flange 14 and the pump housing 15.

  A motor chamber 18 is formed inside the motor housing 16, and an electric motor M is accommodated in the motor chamber 18. The electric motor M includes a stator 19 that is fixed to the inner surface of the motor housing 16 and a rotor 20 that is fixed to the drive shaft 21 so as to be integrally rotatable and rotatable relative to the stator 19. The stator 19 has a stator coil 19a, and the stator coil 19a is electrically connected to motor power terminals 27 and 28 via a plurality of (three in this embodiment) lead wires L. When a current flows from the external power source to the stator coil 19 a via the motor power terminals 27 and 28, the drive shaft 21 is rotated by electromagnetic induction between the stator coil 19 a and the rotor 20.

  In the electric pump P, the pump housing 15 is positioned on the connection flange 14 by a plurality of positioning pins 17 (only one positioning pin 17 is shown in FIG. 2). Further, in the pump housing 15, an insertion hole 15 a is formed above the wiring hole 14 a in the connection flange 14, and the motor chamber 18 and the wiring hole 14 a (recess F) communicate with each other through the insertion hole 15 a. . Accordingly, the opening 14b of the wiring hole 14a opens toward the motor chamber 18 through the insertion hole 15a.

  A pump chamber 31 is defined between the joint portion of the pump housing 15 and the connection flange 14, and a pump portion 32 is provided in the pump chamber 31. The pump unit 32 includes a gear train that rotates as the drive shaft 21 rotates. As shown in FIG. 3, the gear train includes a gear 34 fixed to the lower end portion (tip portion) of the drive shaft 21, and a driven shaft 35 that can mesh with the gear 34 and is arranged in parallel with the drive shaft 21. And a gear 36 integrally formed therewith.

  A key 37 extending along the axial direction of the drive shaft 21 is attached to the peripheral surface of the lower end portion (tip portion) of the drive shaft 21, and the gear 34 is locked to the key 37. The driven shaft 35 is arranged so that the axial direction of the driven shaft 35 is parallel to the axial direction of the drive shaft 21. As shown in FIG. 2, the driven shaft 35 has an upper end rotatably supported by the pump housing 15 via a bearing 38a and a lower end rotatably supported by the connection flange 14 via a bearing 38b. As shown in FIG. 3, the teeth 36 a of the gear 36 mesh with the teeth 34 a of the gear 34 of the drive shaft 21, and the gears 34 and 36 are rotated when the drive shaft 21 rotates.

  A discharge chamber 40 for discharging DME that has passed through the gear train is formed in the pump chamber 31, and the discharge chamber 40 communicates with a discharge passage 40 a that penetrates the connection flange 14. The discharge passage 40 a is connected to the discharge pipe 11. The pump housing 15 is formed with a suction passage 41 for sucking DME into the gear train. The suction passage 41 is opened from the pump housing 15 toward the tank T via a suction port (not shown). Yes. The motor chamber 18 and the pump chamber 31 communicate with each other via a gap between the gears 34 and 36 and the pump housing 15 and a gap between the drive shaft 21 and the pump housing 15. Therefore, the housing, that is, the motor chamber 18 and the pump chamber 31 are filled with DME. The state in which the housing is filled with DME means not only the state in which the entire housing is filled with DME, but also the entire pump chamber 31 and a part of the motor chamber 18 are filled with DME. This includes a state in which some voids exist in the chamber 18.

  In the electric pump P configured as described above, when the drive shaft 21 rotates in the direction of the arrow Z1 in FIG. 3 (counterclockwise direction in FIG. 3) by the driving force of the electric motor M, the driven shaft 35 is moved along with the drive shaft 21. Rotate in the direction of the white arrow Z2 in FIG. 3 (clockwise direction in FIG. 3). Then, the pump unit 32 is driven, and the DME in the tank T is introduced into the suction passage 41 via the suction port. Further, DME is transferred to the discharge chamber 40 along the peripheral surface of the pump chamber 31 as the gears 34 and 36 rotate. The DME transferred to the discharge chamber 40 is pumped to the discharge pipe 11 via the discharge passage 40 a as the gears 34 and 36 rotate, and further supplied to the injection pump 12.

Next, the arrangement state of the lead wire L will be described in detail.
As shown in FIGS. 2 and 4, in the motor chamber 18, the lead wire L has an upper end (one end) connected to the stator coil 19a and a lower end (the other end) connected to the motor power terminals 27 and 28. It is connected to the. The lead wire L is arranged so as to go from the upper end side (stator coil 19a side) to the lower end side (motor power supply terminals 27 and 28 side) along the rotation direction (arrow Z1 direction) of the drive shaft 21. Yes. The lower end side of the lead wire L is inserted into the insertion hole 15a of the pump housing 15 and connected to the motor power terminals 27 and 28 in the wiring hole 14a. In a state where the stator coil 19a and the motor power terminals 27 and 28 are electrically connected via the lead wire L, the lead wire L moves from the stator coil 19a toward the motor power terminals 27 and 28, and the drive shaft 21. It is arrange | positioned so that it may extend spirally along the circumferential direction.

  Further, in the state where the lead wire L extends in the spiral shape, the length of the lead wire L is the same as the length of 1/4 to 3/4 of the entire circumference of the stator 19. That is, the lead wire L is not arranged so as to extend linearly from the stator coil 19a toward the wiring hole 14a (insertion hole 15a).

  In the state before the electric pump P is connected to the tank T, the lead wire L and the motor power terminals 27 and 28 are not connected, and the blocking body 25 is removed from the connection flange 14. And the assembly | attachment of the connection flange 14 and the interruption | blocking body 25 is performed as follows. First, the lead wire L connected to the stator coil 19a is drawn out of the connection flange 14 through the insertion hole 15a and into the wiring hole 14a. At this time, since the length of the lead wire L is 1/4 to 3/4 of the entire circumference of the stator 19, the lead wire L passes through the insertion hole 15a and the wiring hole 14a to the outside of the connection flange 14. Withdrawing is done with a margin. Then, the end portion of the lead wire L drawn out is inserted into the motor power terminals 27 and 28 and soldered as necessary. Thereafter, the blocking body 25 is fitted into the wiring hole 14a and fixed with the circlip C. As a result, the blocking body 25 is assembled to the connection flange 14.

  Now, in the pumping state of DME by the electric pump P, the flow of DME flowing in the same direction as the rotation direction of the drive shaft 21 and the rotor 20 in the housing due to the rotation of the drive shaft 21 and the rotor 20 by the driving force of the electric motor M. Has occurred. Here, in the motor chamber 18, since the lead wire L is disposed along the rotation direction of the drive shaft 21 and the rotor 20, the flow of DME is transmitted along the direction in which the lead wire L extends.

  The lead wire L extends from the stator coil 19a into the insertion hole 15a and the wiring hole 14a along the rotational direction of the drive shaft 21. For this reason, the flow of DME is transmitted along the lead wire L, thereby being transmitted into the insertion hole 15a and further into the wiring hole 14a via the opening 14b of the wiring hole 14a. Therefore, the flow of DME causes a flow of DME in the wiring hole 14a (recessed portion F) and prevents DME from staying in the wiring hole 14a.

According to the above embodiment, the following effects can be obtained.
(1) The lead wire L is disposed so as to extend spirally along the rotation direction of the drive shaft 21 from the upper end to the lower end, and the lower end of the lead wire L is drawn into the wiring hole 14a. For this reason, the flow of DME generated by the rotation of the drive shaft 21 and the rotor 20 is transmitted into the wiring hole 14 a by the lead wire L. The flow of DME in the wiring hole 14a by the flow can prevent DME from staying in the wiring hole 14a. As a result, metal powder generated by driving the pump unit 32, metal powder generated by bearing wear, and metal powder adhering to the tank and piping connected to the tank are contained in the DME in the housing. Even if it exists, it becomes difficult for the metal powder to enter the wiring hole 14a, and furthermore, the metal powder that has entered the wiring hole 14a can flow out of the wiring hole 14a. In addition, even if the metal powder settles in the wiring hole 14a after the electric pump P is stopped, when the electric pump P is started again, the lead wire L arranged in the liquid (DME) immediately after the start. In addition, the flow of DME can be generated in the wiring hole 14a, and the metal powder precipitated in the wiring hole 14a can flow out of the wiring hole 14a. As a result, the metal powder is prevented from precipitating in the wiring hole 14a of the connecting flange 14, and the metal powder insulates the motor power terminals 27, 28 and the blocking body 25 from each other, and thus the electric pump P. It can prevent that property falls.

  (2) The electric pump P is inserted into the tank T from the bottom wall Ta side of the tank T that stores the liquid DME, and the connection flange 14 is connected to the bottom wall Ta of the tank T. . Therefore, the lead wire L extending spirally along the rotation direction of the drive shaft 21 is disposed in the liquid (DME).

  Here, gas has higher fluidity than liquid (DME), but there is no force to move the metal powder. On the other hand, the liquid (DME) has a lower fluidity than the gas, but a force that moves the metal powder can be generated by adding a small amount of flow to the liquid (DME). That is, the lead wire L arranged in the liquid (DME) transmits the DME flow caused by the rotation of the drive shaft 21 and the rotor 20 into the wiring hole 14a, thereby generating the DME flow in the wiring hole 14a. The entry of the metal powder into the wiring hole 14a is suppressed, and even if it enters, it can flow out. Even if the gas flow is transmitted into the wiring hole 14a by the lead wire L arranged in the gas, it is difficult to suppress or flow out the metal powder into the wiring hole 14a. is there.

  (3) Since the electric pump P is inserted into the tank T from the bottom wall Ta side of the tank T, the opening 14 b on the motor chamber 18 side of the wiring hole 14 a opens toward the motor chamber 18. As described above, even when the metal powder easily enters the wiring hole 14a, the DME flow generated in the motor chamber 18 is transmitted to the wiring hole 14a by the lead wire L and flows into the wiring hole 14a. By making this occur, it is difficult for metal powder to enter the wiring hole 14a, and even if it enters, it can flow out. That is, the configuration in which the flow of DME is transmitted into the wiring hole 14a using the lead wire L and the flow is generated in the wiring hole 14a is effective when the electric pump P is installed on the bottom wall Ta of the tank T. Become.

  (4) The blocking body 25 is located below the opening 14 b on the motor chamber 18 side of the wiring hole 14 a, and constitutes the bottom of the recess F recessed with respect to the motor chamber 18. In such a shape, the metal powder is very easily accumulated in the wiring hole 14a, and the DME in the wiring hole 14a is particularly stagnant. Therefore, the configuration in which the DME flow is generated in the wiring hole 14a using the lead wire L is particularly effective for the shape in which the DME in the wiring hole 14a tends to stay.

  (5) Since the lead wire L is disposed so as to extend along the rotation direction of the drive shaft 21 and the rotor 20, the lead wire L does not greatly hinder the flow of DME. For this reason, DME is agitated in the entire motor chamber 18 and DME can be prevented from staying in a part of the motor chamber 18. Therefore, the temperature of the DME in the motor chamber 18 is made uniform, and the heat dissipation of the electric motor M is improved.

  (6) The lead wire L is drawn into the wiring hole 14 a so as to extend spirally along the rotational direction of the drive shaft 21 and the rotor 20. That is, the length of the lead wire L from the upper end connected to the stator coil 19a to the lower end connected to the motor power terminals 27 and 28 is, for example, from the stator coil 19a toward the wiring hole 14a. It is longer than when L is linearly extended and drawn into the wiring hole 14a. Therefore, the lead wire L can be pulled out of the connection hole 14 from the wiring hole 14a with a margin, and the connection work between the lead wire L and the motor power terminals 27 and 28 can be performed with a margin.

In addition, you may change the said embodiment as follows.
The connecting flange 14 of the electric pump P may be inserted into the tank T from the side wall side of the tank T, and the electric pump P may be installed sideways by connecting the connecting flange 14 to the side wall.

A configuration other than the gear pump including the gears 34 and 36 may be used as the pump unit.
The present invention may be applied to the electric pump P in which the motor housing 16 is joined to the connection flange 14 and the pump housing 15 is joined to the motor housing 16 to constitute the housing.

The figure which shows typically the fuel supply apparatus of embodiment. Sectional drawing which shows an electric pump. Sectional drawing which shows a pump part. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 schematically showing the arrangement of the lead wires.

Explanation of symbols

  L ... lead wire, M ... electric motor, P ... electric pump, T ... tank, Ta ... bottom wall, 14 ... connection flange constituting the housing, 14a ... wiring hole, 14b ... opening on the motor chamber side, 15 ... housing A pump housing constituting 16; a motor housing constituting the housing; 18 a motor chamber; 21 a drive shaft as a rotating shaft; 25 a blocking body; 27 and 28 a motor power supply terminal;

Claims (3)

An electric pump that is installed in a tank that stores liquid, and that pumps the liquid in the tank to the outside of the tank,
A pump part for pumping the liquid is housed inside the housing, and a motor chamber is formed for housing an electric motor for rotating the rotating shaft to drive the pump part. A connecting flange for connecting the housing to the tank is provided, and a wiring hole is formed in the connecting flange for passing a lead wire electrically connected to the electric motor in the housing. In addition, the housing is substantially filled with the liquid, and the wiring hole is provided with a blocking body for blocking the inside of the housing from the outside. The blocking body is for a motor connected to an external power source. A power supply terminal is provided, and the lead wire is electrically connected to the motor power supply terminal, and the lead wire is connected from the electric motor to the motor power supply terminal. Headed electric pump, characterized in that it is arranged to extend spirally along the rotating direction of the rotary shaft. The electric pump is inserted into the tank from the bottom wall side of the tank, and the connection flange is connected to the bottom wall of the tank. The electric pump is used above the wiring hole in the housing. The electric pump according to claim 1, wherein a chamber is arranged, the wiring hole opens toward the motor chamber, and the blocking body forms a bottom portion of the wiring hole. The electric pump according to claim 2, wherein the blocking body is positioned below the opening on the motor chamber side of the wiring hole.

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