JP2010048220A - Motor for fuel pump, and method of controlling application of voltage to the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor for fuel pump capable of noticing heating of a coil part to a user, and to provide a method of controlling application of voltage to the same. <P>SOLUTION: A thermistor 36 is fitted to the top surface of a core 26 of a motor 14 for fuel pump, and the thermistor 36 is connected between a segment of a commutator 30 and a shaft 24. A display meter 46 capable of displaying potential of the shaft 24 is provided. Voltage of the current passed through the thermistor 36 from a plus side of a direct current power source 34 can be known by an indicator of the display meter 46. In the case wherein the temperature of a specified segment is lowered, voltage to be applied is temporarily raised to eliminate malfunction such as filming by a cleaning effect of rectified spark. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor and a method for controlling an applied voltage to the motor.

  As a fuel pump control device for controlling a fuel pump in a fuel tank, Patent Document 1 discloses a fuel pump drive current control based on an output result of a fuel pump coil temperature sensor or the like. There is a document that displays a warning when the estimated brush deterioration amount calculated from the detection value or the like exceeds a predetermined value.

However, in the configuration of Patent Document 1, when the temperature detected by the fuel pump coil temperature sensor is high, the drive current of the fuel pump is merely controlled, so that the user cannot know this temperature rise. . The warning display is also made only when the estimated brush deterioration amount exceeds a predetermined value, and the user cannot know this when the temperature is high.
JP 2007-262935 A

  In view of the above facts, an object of the present invention is to obtain a fuel pump motor capable of notifying the user of the heat generated in the coil section and a method for controlling the voltage applied to the fuel pump motor.

  According to the first aspect of the present invention, a rotating body that includes a shaft, a core fixed around the shaft, and a coil portion wound around the shaft, and that rotates the fuel pump by rotation of the shaft, and the coil A commutator for changing the direction of the current to the part, a thermistor for changing the electric resistance in accordance with a temperature change of the coil part, and a temperature change of the coil part of a predetermined value or more by the electric resistance change of the thermistor. And an informing means for informing when it is detected.

  In this fuel pump motor, the coil portion wound around the core is energized, and the shaft rotates by changing the direction of the current to the coil portion by the commutator. The fuel pump is rotationally driven by the rotation of the shaft.

  In this fuel pump motor, a thermistor that changes the electrical resistance in accordance with the temperature change of the coil portion, and a notification when a temperature change of the coil portion that is equal to or greater than a predetermined value is detected due to the electrical resistance change of the thermistor. Informing means is provided. Therefore, the user can know the temperature change of the coil part by the notification by the notification means. It is also possible to take measures if necessary.

  According to a second aspect of the present invention, in the first aspect of the present invention, the commutator includes a plurality of segments, and the thermistor is electrically connected to the segments and the shaft to detect the potential of the shaft. Has been.

  Therefore, since the thermistor is electrically connected to the segment and the shaft, it is possible to detect an increase in the temperature of the coil portion by reading the current flowing through the thermistor as a potential.

  According to a third aspect of the present invention, in the second aspect of the invention, the shaft and the core are contacted, and the thermistor is connected to the shaft via the core.

Since the shaft and the core are in contact and conductive, the thermistor can be connected to the segment and the shaft by connecting the thermistor to the shaft via the core, and the circuit configuration can be simplified.
According to a fourth aspect of the present invention, in the second or third aspect of the invention, the plurality of thermistors connected to the plurality of the segments are provided.
Therefore, for each segment, it is possible to detect a change in potential of the corresponding shaft, that is, a temperature change in the coil portion.

  According to a fifth aspect of the present invention, in the method for controlling applied voltage to the fuel pump motor according to the fourth aspect, the potential of the shaft is detected for each of the plurality of segments of the commutator, and the specific segment is detected. When the potential is low, the applied voltage is temporarily increased.

  Therefore, when the potential (potential difference) with the shaft in a specific segment is low, it is determined that a conduction failure or the like has occurred between the member (for example, brush) corresponding to the specific segment due to so-called filming or the like. it can. In this case, by temporarily increasing the applied voltage, the cleaning effect by the rectifying spark can be exhibited and the conduction failure can be eliminated.

  Since the present invention has the above-described configuration, it is possible to notify the user of the heat generated in the coil portion.

  FIG. 1 shows a schematic configuration of a fuel pump 12 including a fuel pump motor 14 according to the first embodiment of the present invention. The fuel pump 12 is disposed in a fuel tank (not shown), and is used to send the fuel in the fuel tank to an external device such as an engine.

  The fuel pump 12 has a housing 16 formed in a substantially cylindrical shape. Particularly in the present embodiment, the housing 16 is formed of a conductive material (metal material).

  A pump chamber casing 18 is fitted into the bottom of the housing 16. The pump chamber casing 18 is also formed of a conductive material (metal material), and a thrust bearing 20 is provided at the center thereof. The thrust bearing 20 rotatably supports a shaft 24 described later. A turbine pump body 22 made of resin is provided above the thrust bearing 20. As the shaft 24 rotates, the turbine pump body 22 sends the fuel in the fuel tank upward.

  A fuel pump motor 14 is accommodated in the central portion of the housing 16. The fuel pump motor 14 has a shaft 24 located in the center and a core 26 disposed around the shaft 24. The core 26 is made of metal, and the shaft 24 is press-fitted into the center thereof. Therefore, the shaft 24 and the core 26 are electrically connected.

  As described above, the lower end of the shaft 24 is rotatably supported by the thrust bearing 20, but the upper portion of the shaft 24 is also rotatably supported by the bearing 28. A commutator 30 is disposed between the bearing 28 and the core 26. A plurality of brushes 32 are arranged on the upper side of the commutator 30 and are supplied with electric power from a DC power source 34.

  A plurality of thermistors 36 corresponding to the segments of the commutator 30 are attached to the upper surface of the core 26. In the present embodiment, as shown in FIG. 2A, first, one end (lower surface) of the thermistor 36 is soldered to the core 26 before the conducting wire 58 (see FIG. 2B) is wound around the core 26. The other end is connected to the commutator 30 (corresponding segment) by a conducting wire (covered wire) 54. Therefore, one end of the thermistor 36 is electrically connected to the shaft 24 through the core 26. Then, as shown in FIG. 2B, a conductive wire 58 is wound around the thermistor 36 and the core 26 so as to cover them to form a coil portion 38. Thereby, the rotary body 40 (armature) provided with the shaft 24, the core 26, and the coil part 38 (thermistor 36 is included in the inside) is comprised as a whole.

  And the direction of the electric current to the coil part 38 is changed by the commutator 30, and the shaft 24 and the core 26 can be rotated continuously. In the present embodiment, the thermistor 36 is provided corresponding to each of the plurality of segments of the commutator 30. In the present embodiment, in particular, a CTR (critical temperature resister) thermistor is used as the thermistor 36.

  A magnet 42 is attached to the inner surface side of the housing 16 at a position corresponding to the core 26.

  The upper part of the housing 16 is covered with a lid member 44. A housing recess 44A for housing the bearing 28 and a housing recess 44B for housing the brush 32 are formed on the lower surface side of the lid member 44, and the power supply line 52 extends from the housing recess 44B to the outside. ing. The electric power from the DC power supply 34 is supplied from the power supply line 52 to the fuel pump motor 14 (brush 32). Further, a display meter 46 is connected by a conducting wire 56 between an intermediate portion of the power supply line 52 (on the positive side of the DC power supply 34) and the housing 16. The display meter 46 is attached, for example, to an instrument panel or the like in the passenger compartment so that the user can visually recognize the pointer.

  Since the shaft 24, the thrust bearing 20, the pump chamber casing 18, and the housing 16 are all made of a conductive material, the indicator of the display meter 46 swings in accordance with the potential of the shaft 24. Further, since the thermistor 36 is a resistor having a large change in electrical resistance with respect to a temperature change, in the configuration of the present embodiment in which the thermistor 36 is disposed in the coil portion 38, the thermistor 36 has an electrical resistance corresponding to the temperature of the coil portion 38. Resistance changes. Here, since the thermistor 36 is connected between the segment of the commutator 30 and the shaft 24, as a result, the voltage of the current that has passed through the thermistor 36 from the positive side of the DC power supply 34 is indicated by the pointer of the display meter 46. Can know by.

  The lid member 44 is formed with a delivery hole 48 penetrating in the vertical direction, and the fuel sent upward by the turbine pump body 22 is delivered to the outside from the delivery hole 48.

  In the fuel pump motor 14 of this embodiment configured as described above, when the coil portion 38 generates heat and reaches a temperature equal to or higher than a predetermined value, the electrical resistance of the thermistor 36 also changes greatly, which is touched by the pointer of the display meter 46. Is displayed. Therefore, the user can know the temperature rise of the coil portion 38 and can take measures as necessary. The “predetermined value” here can be set in advance according to the identification of the thermistor 36 and the like.

  Particularly in this embodiment, the thermistor 36 is connected between the segment of the commutator 30 and the shaft. Therefore, the voltage of the current that has passed through the thermistor 36 from the positive side of the DC power supply 34 can be known from the pointer of the display meter 46. Moreover, the shaft 24 is press-fitted into the core 26, and there is conduction between them. Therefore, a circuit configuration for detecting the potential of the shaft 24 can be easily obtained.

  Moreover, in the present embodiment, the thermistor 36 is directly attached to the core 26 of the rotating body 40. Therefore, more accurate detection is possible by causing the heat of the coil portion 38 to directly act on the thermistor 36.

  In order to detect and notify the heat generation of the coil portion 38 as described above, at least one thermistor 36 may be disposed. In the present embodiment, a plurality of thermistors 30 corresponding to each segment are provided. A thermistor 36 is provided. Therefore, it is also possible to specify the coil part 38 that is generating heat.

  The thermistor 36 is not limited as long as the electrical resistance changes with respect to the assumed temperature change of the coil portion 38 and can detect this temperature change. For example, the CTR thermistor described above is not limited to a specific one. Since the change in electrical resistance when the temperature (excitation temperature) is exceeded is large and the detection capability is high, it is preferably used in this embodiment.

  In addition, a plurality of thermistors having different excitation temperatures may be used so that detection can be performed according to the heat generation level in the coil section 38. For example, since a thermistor having a low excitation temperature can be used to know a sign of heat generation in the coil section 38, it can be displayed on the display meter 46 or the like at an early stage to prompt the user to take early measures.

  Further, a PTC (positive temperature coefficient) thermistor or an NTC (negative temperature coefficient) thermistor may be connected to each segment of the commutator 30 so that the potential generated in the shaft 24 can be detected for each segment. In this configuration, an increase in electrical resistance due to the PTC thermistor and a decrease in electrical resistance due to the NTC thermistor occur at different excitation temperatures in accordance with the heat generation of the coil section 38, so these thermistors according to the heat generation state. The combination of changes in the electrical resistance can be detected as a potential, and the heat generation state of each coil section 38 can be known more accurately.

  In each of the above-described configurations, the thermistor 36 is connected to each segment of the commutator 30. Accordingly, a relative temperature change is detected for each segment, in other words, for each coil section 38, and is displayed on the display meter 46 when the temperature of a specific segment (coil section 38) is higher than other segments. By doing so, even if the temperature rise of the coil portion 38 is small, it can be detected.

  In the configuration in which the thermistor 36 is provided in each segment (coil portion 38) as described above, it is also possible to detect that the temperature of a specific segment is decreased (the amount of generated heat is small). For example, when so-called filming occurs between the brush 32 and the commutator 30, it can be determined that the above-described temperature drop has occurred due to poor conduction. In this case, the applied voltage can be temporarily increased manually or by an instruction from an engine control computer (not shown), and defects such as filming can be eliminated by the cleaning effect of the rectifying spark.

  In the above description, the display meter 46 is connected using the conductive housing 16. In short, the thermistor 36 detects the temperature rise (heat generation) of the coil portion 38, and the display meter 46 It only needs to be displayable. For example, a display meter 46 may be connected to the bearing 28 instead of the housing 16 like the fuel pump motor 64 of the second embodiment shown in FIG.

  The position of the thermistor 36 is also the side surface of the core 26 in the second embodiment. Thus, the connection part of the display meter 46 and the position of the thermistor 36 are not particularly limited. However, when one end of the thermistor 36 is brought into contact with the core 26, it can be electrically connected to the shaft 24 via the core 26, and the circuit configuration can be simplified. In addition, in 2nd Embodiment, the point which is different from 1st Embodiment is shown schematically, and the same code | symbol is attached | subjected about the component same as 1st Embodiment, and detailed description is abbreviate | omitted. Moreover, in 2nd Embodiment, illustration of some members, such as the housing which comprises a fuel pump, is abbreviate | omitted.

  In addition, the notification means of the present invention is not limited to the display meter 46 described above, and may be configured to notify by a lamp or voice, for example.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing a fuel pump to which a fuel pump motor according to a first embodiment of the present invention is applied, partially broken away. It is explanatory drawing which shows a part of process which comprises the motor for fuel pumps of 1st Embodiment of this invention to (A)-(B) in order. It is a schematic front view which shows the motor for fuel pumps of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Fuel pump 14 Fuel pump motor 16 Housing 18 Pump chamber casing 20 Thrust bearing 22 Turbine pump main body 24 Shaft 26 Core 28 Bearing 30 Commutator (commutator)
32 Brush 34 DC power supply 36 Thermistor 38 Coil unit 40 Rotating body 42 Magnet 46 Display meter (notification means)
64 Fuel pump motor

Claims (5)

A rotating body that includes a shaft, a core fixed around the shaft, and a coil portion wound around the core, and that rotates the fuel pump by rotation of the shaft;
A commutator for changing the direction of current to the coil section;
A thermistor that changes electrical resistance in accordance with a temperature change of the coil portion;
An informing means for informing when a temperature change of the coil portion of a predetermined value or more is detected by an electrical resistance change of the thermistor;
A fuel pump motor. The commutator comprises a plurality of segments;
The fuel pump motor according to claim 1, wherein the thermistor is electrically connected to the segment and the shaft so that the potential of the shaft can be detected. The shaft and the core are contacted;
The fuel pump motor according to claim 2, wherein the thermistor is connected to the shaft via the core.   The fuel pump motor according to claim 2, further comprising a plurality of thermistors connected to each of the plurality of segments. A method for controlling an applied voltage to a fuel pump motor according to claim 4,
Detecting the potential of the shaft for each of a plurality of segments of the commutator;
An applied voltage control method for temporarily increasing the applied voltage when the potential is low in a specific segment.

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