Fuel pump, fuel supply equipment using fuel pump and method for manufacturing fuel pump

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2004-110164 filed on Apr. 2, 2004, No. 2004-266739 filed on Sep. 14, 2004, No. 2004-327367 filed on Nov. 11, 2004, and No. 2004-355575 filed on Dec. 8, 2004, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to an in-tank type fuel pump for a motorcycle, fuel supply equipment using the fuel pump and a method for manufacturing the fuel pump.

BACKGROUND OF THE INVENTION

In general, it has been well known in the art to provide a motor in which a current fed to a rotor having a coil wound around it is controlled by a commutator and the rotor is rotated. Then, as a driving source for a fuel pump for absorbing the fuel in the fuel tank and feeding the fuel to an engine acting as a fuel consumption device, there has been used the motor controlled by the commutator as described above (refer to Patent Document 1, for example). However, the motor controlled by the commutator has some disadvantages that a motor efficiency is decreased with the result that an efficiency of the motor is decreased because a sliding resistance between the commutator and a brush and a fluid resistance received at the grooves formed for dividing the commutator into each of the segments are generated. A fuel pump efficiency used herein is defined by (a motor efficiency)×(a pump efficiency). The motor efficiency and pump efficiency are defined by (a motor efficiency)=(T·N)/(I·V), (a pump efficiency)=(P·Q)/(T·N), where I is a driving current fed to the motor part of the fuel pump, V is a voltage to be applied, T is a torque at the motor part, N is the number of rotation of the motor part, P is a pressure of fuel discharged by the fuel pump and Q is a fuel discharging amount. Accordingly, a relation of (a fuel pump efficiency)=(a motor efficiency)×(a pump efficiency)=(P·Q)/(I·V) can be attained.

In addition, the motor controlled by the commutator shows a problem that a motor lifetime becomes short due to a wearing at the sliding locations between the commutator and the brush.

There has been well known in the prior art to provide a brushmotor for rotating the rotor while controlling a current fed to the rotor having a coil wound around it with the commutator. Then, as a driving source for a fuel pump for absorbing the fuel in the fuel tank and feeding the fuel to an engine acting as a fuel consumption device, there has been used the brushmotor as described above (refer to Patent Document 1, for example).

[Patent Document 1] JP-7-85642A

Water entering into a fuel tank under an absorbing action performed at the fuel tank or water generated by dew formation in the fuel tank is sometimes accumulated at the bottom part of the tank when the fuel pump is installed in the fuel tank of the fuel supply equipment fixed to the bottom wall of the fuel tank in a motorcycle, for example.

Accordingly, when the fuel pump using the brushmotor is installed within the fuel tank, it is necessary to increase a height of the fuel pump installed in the fuel tank in such a way that the position where the brush and the commutator are formed may be increased more than that of water accumulated at the bottom part in the fuel tank. A reason why this state occurs consists in a possibility that when the brush and the commutator are immersed in the water, the segments constituting the commutator are electrically short circuited or the commutator and the brush are electrically short circuited in the brushmotor, since a current fed to the rotor having a coil wound around it is controlled through a contacted state between the commutator and the brush to rotate the rotor.

As described above, when a height of the fuel pump installed in the fuel tank is increased, there occurs a problem that a structure for installing the fuel pump in the fuel tank becomes complex.

In regard to such fuel supply equipment, the Patent Document 2, for example, discloses a system in which a suction port of the fuel pump is placed in the fuel tank and the fuel pump is fixed to the outer surface of the bottom part of the fuel tank. The Patent Document 1 discloses a system in which the commutator and the brush are immersed in the water accumulated at the bottom part in the fuel tank to prevent an electrical short-circuited state through this configuration. In addition, a structure for mounting the fuel pump to the fuel tank becomes simple because the fuel pump is not fixed inside the fuel tank, but the fuel pump is fixed to the outer surface of the bottom part of the fuel tank.

In addition, the Patent Document 2 discloses a utilization of brushless motor acting as a driving part for the fuel pump in which even if water enters into the fuel pump, it is possible to prevent an electrical short-circuited state at the motor because the brushless motor is used as the driving part for the fuel pump.

[Patent Document 2] JP-2003-120455A

When it is tried to utilize the fuel pump having a commutator controlled motor of a four-wheeled vehicle as a driving source for a motorcycle where a battery capacity that can be mounted on the motorcycle is low due to a narrow installing space, an assurance of electrical power supplied to the fuel pump sometimes becomes difficult because an efficiency of the fuel pump is low. In addition, when the fuel tank is small in size for the motorcycle, it is difficult to mount the fuel pump in the fuel tank.

Additionally, deteriorated fuel or low quality fuel containing alcohol, for example, may be used in a motorcycle and when the fuel pump having a commutator controlled motor is mounted on the motorcycle utilizing such a deteriorated fuel or low quality fuel as above, electric corrosion or corrosion may occur at the sliding contact portion between the commutator and the brush and an inferior electrical conduction state may occur.

In order to solve the aforesaid problem, the present invention has been invented and it is an object of the present invention to mount a fuel pump having a high efficiency, small-size, high oil-resistance characteristic and long life within the fuel tank of the motorcycle.

There occurs a problem in the brushmotor that a motor efficiency is reduced with the result that a fuel pump efficiency is reduced by a sliding resistance between the commutator and the brush as well as a fluid resistance received at the grooves arranged for dividing the commutator into each of the segments. The fuel pump efficiency used herein is defined by (a motor efficiency)×(a pump efficiency). The motor efficiency and pump efficiency are defined by (a motor efficiency)=(T·N)/(I·V), (a pump efficiency)=(P·Q)/(T·N), where I is a driving current fed to the motor part of the fuel pump, V is a voltage to be applied, T is a torque at the motor part, N is the number of rotation of the motor part, P is a pressure of fuel discharged by the fuel pump and Q is a fuel discharging amount. That is, the efficiency of the fuel pump expresses an efficiency of work performed by the fuel pump against the electrical power fed to the fuel pump.

With the foregoing description, it is necessary to increase an electrical power fed to the fuel pump and make a large-sized fuel pump in order to attain a desired discharging amount of fuel under application of the fuel pump having a low motor efficiency.

In addition, the brushmotor has a problem that the motor life becomes short due to a wearing of the sliding portion between the commutator and the brush.

Additionally, when deteriorated fuel or low quality fuel is used as fuel, application of the brushmotor to the fuel pump causes the sliding portion between the commutator and the brush to generate an electrical corrosion or poor electrical contact and there occurs a possibility that an electrical non-conductive state is produced.

In addition, when the coil of the rotor in the aforesaid brushmotor is formed in a distributed winding type where the coil is wound over a plurality of teeth, the windings at the coil ends are crossed to each other and it becomes difficult to increase a rate of occupancy of the winding per magnetic pole. The rate of occupancy of the winding defined herein is a rate of winding area occupied in a winding space. Accordingly, when the rate of occupancy is decreased, an amount of winding wound in the same winding space is decreased. As a result, a large winding space becomes necessary for forming a coil with the desired amount of winding and then a size of the motor part is made large.

The present invention has been invented for solving the aforesaid problem and it is an object of the present invention to provide a fuel pump having a high efficiency, small-size, superior corrosion-proof characteristic and a long life.

When the fuel pump is fixed to the outer surface of the bottom part of the fuel tank as disclosed in the Patent Document 2, it is necessary to provide a seal structure for preventing fuel from leaking out of the fuel pump through the pump chamber for pressurizing fuel sucked at the intake port. In the Patent Document 1, for example, there may be provided a technical concept that a seal is applied between the pump chamber and the bearing for the rotary shaft connecting the impellor with the rotor. However, it is hard to seal between the bearing slidingly contacted with the rotary shaft and the pump chamber, and the Patent Document 2 does not disclose a structure for sealing between the pump chamber and the bearing.

In addition, even if the pump chamber and the bearing can be sealed to each other, there remains a problem that a sliding resistance is increased and the sliding friction is increased because the sliding part between the rotary shaft and the bearing is not lubricated with fuel.

The present invention has been invented in order to solve the aforesaid problem and it is an object of the present invention to provide fuel supply equipment in which a fuel pump is mounted in the fuel tank and fixed to the bottom wall of the fuel tank, wherein a structure for mounting the fuel pump in the fuel tank is simple, a seal structure in the fuel pump is simple, a sliding resistance and a sliding wear in the fuel pump are reduced and an electrical short-circuited state in the fuel pump is prevented.

SUMMARY OF THE INVENTION

The inventions described in claims are operated such that some magnetic poles formed in a circumferential direction of a stator core are changed over under controlling of an electrical energization for the coils wound around the stator core, the rotating members at the pump is rotated together with the rotor through the changing-over of the magnetic poles and a pressure of the fuel is increased. That is, the fuel pump using the brushless motor is installed in the fuel tank of the motorcycle. Both sliding resistance and fluid resistance can be reduced as compared with those of the commutator controlled motor because no commutator is used in the brushless motor. With such an arrangement as above, a motor size can be reduced and its low current can be attained under the same output because the aforesaid motor efficiency is improved with the result that the fuel pump efficiency is improved. Accordingly, it is possible to mount the fuel pump within the fuel tank of the motorcycle having a smaller size as compared with that of a four-wheeled vehicle.

In addition, no electrical corrosion or corrosion occurs at the sliding portion between the commutator and the brush as found in the commutator controlled motor even if the deteriorated fuel or low quality fuel is used because no commutator is used in the brushless motor. Further, a life of the fuel pump is extended because no sliding wear is produced between the commutator and the brush.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view for showing a fuel pump in accordance with the first preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG. 1.

FIG. 3 is a schematic configuration view for showing fuel supply equipment using the fuel pump of the first preferred embodiment.

FIG. 4 is a perspective view for showing an impellor in accordance with the first preferred embodiment.

FIG. 5 is a circuit configuration view for showing a control device in accordance with the first preferred embodiment.

FIG. 6 is a characteristic graph for indicating a relation among a pump outer diameter, an impellor outer diameter, a motor efficiency, a pump efficiency and a total efficiency of the first preferred embodiment.

FIG. 7 is a schematic sectional view for showing the pump part in accordance with the second preferred embodiment.

FIG. 8 is a circuit configuration view for showing a control device in accordance with the third preferred embodiment.

FIG. 9 is a time-chart for indicating an elapse of a total current Ic flowing at the coil PWM.

FIG. 10A is an illustrative view for showing a variation in voltage applied to each of the coils by PWM.

FIG. 10B is an illustrative view for showing a variation in current flowing in each of the coils.

FIG. 11 is a flowchart indicating a control over a total current Ic flowing in the coil by PWM in the third preferred embodiment.

FIG. 12 is a flowchart indicating a control over a total current Ic flowing in the coil by PWM in the fourth preferred embodiment.

FIG. 13 is an illustrative view for showing another control for a voltage applied to each of the coils by PWM.

FIG. 14 is a sectional view for showing a fuel pump in accordance with the fifth preferred embodiment of the present invention.

FIG. 15 is a sectional view taken along line XV-XV of FIG. 14.

FIG. 16 is a sectional view for showing a state in which the coil is formed in accordance with the fifth preferred embodiment.

FIG. 17 is s sectional view for showing a fuel pump in accordance with the sixth preferred embodiment at the same position as that shown in FIG. 15.

FIG. 18A is a sectional view for showing a state before a mother material of the stator core is bent.

FIG. 18B is a sectional view for showing a state after a mother material of the stator core is bent.

FIG. 19 is s sectional view for showing a fuel pump in accordance with the seventh preferred embodiment at the same position as that shown in FIG. 15.

FIG. 20A is a sectional view for showing an outer circumferential core of the stator core.

FIG. 20B is a sectional view for showing the stator core formed with coils before the stator core is assembled to the outer circumferential core.

FIG. 21 is a sectional view for showing the fuel pump in accordance with the eighth preferred embodiment at the same position as that shown in FIG. 14.

FIG. 22A is a sectional view for showing the outer circumferential core of the stator core.

FIG. 22B is a sectional view for showing the stator core formed with coils before the stator core is assembled to the outer circumferential core.

FIG. 23 is a side elevational view for showing fuel supply equipment in accordance with the ninth preferred embodiment of the present invention.

FIG. 24 is a perspective view for showing the fuel supply equipment in accordance with the ninth preferred embodiment of the present invention.

FIG. 25 is a sectional view for showing the fuel pump in accordance with the ninth preferred embodiment of the present invention.

FIGS. 26A and 26B are illustrative views for showing steps for fixing the fuel supply equipment in accordance with the ninth preferred embodiment of the present invention to the fuel tank.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, a plurality of preferred embodiments of the present invention will be described as follows.

First Preferred Embodiment

In FIG. 3 fuel supply equipment using the fuel pump in accordance with the first preferred embodiment of the present invention is illustrated. Afuel pump 1010 in the fuel supply equipment is an in-tank type Wesco pump mounted in a fuel tank 1001 of a motorcycle. A fuel discharging amount required in the fuel pump 1010 is 5 L/h or more to 30 L/h or less. The fuel pump 1010 discharges the fuel in the fuel in the fuel tank 1001 sucked through a suction filter 1200 while its pressure is being increased. The fuel discharged by the fuel pump 1010 passes through a check valve 1202 and a fuel pressure is adjusted by a pressure regulator 1204 and the fuel is fed to the engine acting as a fuel consuming device.

A control device 1210 for use in controlling the driving current fed to the fuel pump 1010 is fixed outside the fuel tank 1001 of the lid member 1002 for closing an opening of the fuel tank 1001. A capacity of the battery of a motorcycle not shown for feeding the driving current to the fuel pump 1010 is a voltage of 12V and a current ranging from 6 A to 10 A. The fuel pump 1010, suction filter 1200, check valve 1202, pressure regulator 1204 and control device 1210 constitute the fuel supply equipment described in the claims.

As shown in FIG. 1 and FIG. 2, the fuel pump 1010 comprises a motor 1012 and a pump 1013 driven by a rotation of the rotor 1030 of the motor 1012 so as to increase a pressure of the sucked fuel.

The motor 1012 is a so-called brushless motor and it has a stator core 1020, coils 1024 and rotor 1030. The stator core 1020 is formed while magnetic steel plates are axially stacked up. As shown in FIG. 2, six teeth 1022 protruded toward the center of the motor 1012 are equally spaced apart in a circumferential direction toward the center of the motor 1012. Coils 1024 are wound around each of the teeth 1022. The resin housing 1014 has both stator core 1020 and the coils 1024 molded together. A metallic housing 1016 is inserted and molded to the resin housing 1014 and an intake side cover 1040 to be described later is fitted to it. Resin of the resin housing 1014 is filled in a plurality of through-holes 1016a arranged at the metallic housing 1016.

The rotor 1030 has a shaft 1022, rotary core 1034 and permanent magnet 1036 and the rotor 1030 is rotatably mounted at the inner circumference of the stator core 1020. The permanent magnet 1036 is formed into one cylindrical member and arranged at the outer circumference of the rotary core 1034. The permanent magnet 1036 forms eight magnetic poles 1037 in its rotating direction. Eight magnetic poles 1037 are magnetically set to form magnetic poles different from each other in a rotating direction at the outer circumferential surface oppositely facing the stator core 1020.

The pump 1013 is a so-called Wesco pump having an intake side cover 1040, discharging side cover 1042 and impellor 1050. The intake side cover 1040 and discharging side cover 1042 are a case member for rotatably storing the impellor 1050 acting as a rotary member. The discharging side cover 1042 is held by the metallic housing 1016 between the resin housing 1014 and the intake side cover 1040. The intake side cover 1040 and the discharging side cover 1042 form pump passages 1110 and 1112 along the impellor grooves 1054 of the impellor 1050 to be described later.

As shown in FIG. 4 of a perspective figure in which the impellor 1050 is seen from the intake side cover 1040, the impellor 1050 is formed in a disc-like plate. The outer circumference of the impellor 1050 is enclosed by an annular part 1052, and impellor grooves 1054 are formed at both sides in the rotary shaft direction at the inner circumference of the annular part 1052. The fuel sucked from the fuel inlet 1100 of the intake side cover 1040 under a rotation of the impellor 1050 flows out of the outside part of the impellor grooves 1054 in a diameter direction into each of the pump passages 1110 and 1112, and then flows into the inner part of the impellor grooves 1054 in a diameter direction positioned at a rear part in the rotating direction. Then, flowing out of the impellor grooves 1054 and flowing-in into the impellor grooves 1054 are repeated in sequence, thereby fuel pressure in the pump passages 1110, 1112 is increased with energy of fuel becoming a circulating flow. The fuel of which pressure is increased at the pump passages 1110, 1112 is discharged out of a fuel outlet 1120 of the discharging side cover 1042, passes through between the stator core 1020 and the rotor 1030 and discharged out of the discharging port 1130.

The aforesaid control device 1210 is a three-phase circuit for switching over the driving current fed to the coils 1024 in the fuel pump 1010 and controlling it. As shown in FIG. 5, the control device 1210 has a control circuit 1212 and a power switching element 1214. The control device 1210 employs a three-phase full wave for driving by ⅔ the coils 1024 wound around the six teeth. The control device 1210 detects an inductive electromotive force generated at the coils 1024 electrically not energized under a rotation of the rotor 1030 and judges a rotating position of the rotor 1030. Then, the driving current fed to the coils 1024 is changed over by the power switching element 1214 on the basis of the rotating position of the judged rotor 1030.

Then, a relation between a performance of the fuel pump 1010 and its size will be described as follows.

At first, it is desirable that a pump outer diameter D0 of the maximum outer diameter of the fuel pump shown in FIG. 1 has a relation of D0<30 mm in order to mount the fuel pump 1010 within the fuel tank 1001 for the motorcycle. In particular, the fuel tank in the motorcycle with a displacement of 150 cc or less is small in size, so that it is recommended that an outer diameter of the fuel pump is made as small as possible in a range fulfilling a requisite performance.

In FIG. 6 is indicated a relation among a fuel pump outer diameter D0, motor efficiency, pump efficiency and total efficiency with a fuel discharging amount in the fuel pump 1010 being 20 L/h and a fuel discharging pressure being 300 kPa.

A total efficiency of the efficiency of the fuel pump 1010 is defined by (a motor efficiency)×(a pump efficiency). The motor efficiency and pump efficiency are defined by (a motor efficiency)=(T·N)/(I·V), (a pump efficiency)=(P·Q)/(T·N), where I is a driving current fed to the motor part 1012, V is a voltage to be applied, T is a torque at the motor part 1012, N is the number of rotation of the motor part 1012, P is a pressure of fuel discharged by the fuel pump 1010 and Q is a fuel discharging amount. Accordingly, a relation of (a total efficiency)=(a motor efficiency)×(a pump efficiency)=(P·Q)/(I·V) can be attained. That is, the total efficiency expresses an efficiency of work performed by the fuel pump 1010 with respect to an electrical power fed to the fuel pump 1010.

As apparent from FIG. 6, when the pump outer diameter D0 of the fuel pump 1010 is 14 mm, this is substantially the same total efficiency as that when the pump outer diameter D0 is 30 mm. Accordingly, it is desirable that the pump outer diameter D0 of the fuel pump 1010 is 14 mm≦D1<30 mm. In particular, the total efficiency becomes maximum near a value where the pump outer diameter D0 is about 20 mm. In this case, the pump outer diameter D0 and the impellor outer diameter D1 are approximately in a proportional relation and when the pump outer diameter D0 is 30 mm, the impellor outer diameter D1 is 26 mm. Accordingly, a range of the impellor outer diameter D1 satisfying a relation of 14 mm≦D0<30 mm is 12.1≦D1<26 m.

Second Preferred Embodiment

In FIG. 7 is illustrated the second preferred embodiment. This preferred embodiment is substantially the same as the constitution of the first preferred embodiment except the fact that the pump 1060 is different from the pump 1013 in the first preferred embodiment. Substantially the same composing portions as those of the first preferred embodiment are denoted by the same reference symbols.

In the second preferred embodiment, the pump 1060 constitutes a trochoid pump. An outer rotor 1064 is stored at the inner circumferential side of the housing 1062, and an inner rotor 1066 is stored at the inner circumference of the outer rotor 1064. Inner teeth 1065 formed at the inner circumference of the outer rotor 1064 are engaged with outer teeth 1067 formed at the outer circumference of the inner rotor 1066. The center of the outer rotor 1065 is eccentric with respect to the center of the inner rotor 1066, and the number of inner teeth 1065 is larger by 1 than that of the outer teeth 1067. When the inner rotor 1066 is rotated by the driving force of the motor 1012, the outer rotor 1064 is also rotated and a pressure of the fuel between the outer rotor 1064 and the inner rotor 1066 is increased.

Third Preferred Embodiment

In FIG. 8 is shown the third preferred embodiment of the present invention. Substantially the same composing elements as those of the first preferred embodiment are denoted by the same reference symbols.

In the third preferred embodiment, a control device 1220 comprises a three-phase circuit 1230, a current detector 1240 and a PWM (Pulse Width Modulation) control part 1250. The three-phase circuit 1230 in the third preferred embodiment is substantially the same circuit as that of the control device 1210 shown in FIG. 5. The three-phase circuit 1230, the current detector 1240 and the PWM control part 1250 are constituted by one tip IC element as one circuit module.

The current detector 1240 compares a total amount of currents flowing in six coils 1024 of the fuel pump 1010 with a predetermined value and transmits the result to the PWM control part 1250.

At the PWM control part 1250 acting as a limiting circuit a corresponding table is made for the PWM values and the counter values. For example, the maximum value of the PWM value is 100% and the minimum value is 0%, the maximum value 100% of the PWM value corresponds to the minimum value 0 in the counter, and the minimum value 0% of the PWM value corresponds to the maximum value of the counter. In the corresponding table, as the counter value is increased, its corresponding PWM value is decreased.

The PWM control part 1250 sets the counter value on the basis of a signal of comparison result transmitted from the current detector 1240, generates the PWM signal in reference to the corresponding table for both the PWM value and the counter value, and transmits it to the control circuit 1212 of the three-phase circuit 1230. As the PWM value is increased, ON time of pulse at the PWM signal shown in FIG. 9 is extended. The PWM value is decreased, ON time of pulse at the PWM signal becomes short.

The control circuit 1212 in the three-phase circuit 1230 performs a switching against an electrical energization for each of the coils 1024 in response to the PWM signal transmitted from the PWM control part 1250. For example, when the control circuit 1212 of the three-phase circuit 1230 performs a switching of the electrical energization for each of the coils 1024 in response to the PWM signal transmitted from the PWM control part 1250 when the PWM value is the maximum value, the voltage applied to each of the coils corresponds to the left side of the arrow in FIG. 10A. To the contrary, when the control circuit 1212 of the three-phase circuit 1230 performs a switching of electrical energization to each of the coils 1024 in response to the PWM signal transmitted from the PWM control part 1250 on the basis of the PWM value smaller than the maximum value, the voltage applied to each of the coils 1024 becomes a value indicated by a right arrow mark in FIG. 10A. That is, when the counter value is increased and the PWM value is decreased, ON time of the voltage applied to the coils 1024 is decreased. As a result, the current flowing in the coils 1024 is decreased as indicated by a right arrow mark as compared with the case that the PWM value indicated by a left arrow mark is the maximum value.

Then, an electrical energization control for the coils 1024 will be described more practically. The step numbers described below correspond to the step numbers in the flow chart indicated in FIG. 11.

(1) An electrical power is accumulated in an electrolysis capacitor or the like to supply a starting electrical power by supplying the starting electrical power from the battery with an engine key being turned or by kicking against the kick lever when the battery is completely discharged. Then, at first, a counter (CT) is cleared (Step 1300). When the counter is initially cleared at the time of OFF of the power supply, the step 1300 is not required.

(2) The current detector 1240 detects a total current Ic flowing at the coils 1024 (Step 1302), a result of comparison between either the max value or the min. value of the preset current value and Ic is transmitted to the PWM control part 1250.

(3) At the PWM control part 1250, Ic and max value are compared to each other at Step 1304 and when a relation of Ic>max value is attained as indicated by a dotted line in FIG. 9, CT discriminates whether or not it is the maximum value of the counter (Step 1306). If Ct is not the maximum value of the counter, +1 is added to the CT (Step 1308) and the operation is transferred to the step 1316. If a relation of Ic>max value is attained and CT has the maximum value of the counter, the operation is transferred to Step 1316 as it is.

(4) If a relation of Ic≦max value is attained at Step 1304, then a total current Ic is compared with a set value min. (Step 1310) and if a relation of Ic≧min., then the operation is transferred to Step 1316.

(5) If a relation of Ic<min. is attained at Step 1310 as indicated by a dotted line in FIG. 9, CT discriminates whether or not the minimum value in the counter is 0 (Step 1312). If CT is not 0 of the minimum value of the counter, −1 is added to CT (Step 1314) and the operation is transferred to Step 1316. If a relation of Ic<min. is attained and CT has the minimum value of the counter, the operation is transferred to the step 1316 as it is.

(6) PWM control part 1250 calculates the PWM value in reference to the corresponding table of the PWM values and the counter value on the basis of the set counter value and transmits it the control circuit 1212.

(7) The control circuit 1212 of the three-phase circuit 1230 controls an electrical energization for the coils 1024 in reference to the PWM signal transmitted from the PWM control part 1250 (Step 1316).

In the third preferred embodiment, when the total current Ic flowing at the coils 1024 exceeds the set max value, a value of CT is added by +1 or set to the maximum value of the counter. In addition, when the total current Ic flowing at the coils 1024 becomes smaller than the set min. value, CT is added by −1 or set to the minimum value of the counter. In the corresponding table, when the value in CT is increased, the PWM value is decreased and in turn when the value in CT is decreased, the PWM value is increased.

Just after the engine key is turned and an electrical power is fed from the battery or the kick lever is kicked to feed an electrical power, a relation of Ic<min. is attained and CT is already set at the minimum value of 0 in the counter, so that CT is kept 0 until a relation of Ic>max is attained. Accordingly, the PWM value becomes the maximum value. Under this state, when the total current Ic flowing in the coils 1024 is increased and a relation of Ic>max is attained, the counter value is increased and the PWM value corresponding to the counter value is decreased. As a result, as shown in FIG. 9, the total current Ic is controlled not to exceed the max value because ON time of the voltage applied to the coils 1024 under an electrical energization control of the three-phase circuit 1230 is decreased.

In turn, when a relation of Ic<min. is attained, the counter value is decreased and the PWM value corresponding to the counter value is increased. As a result, the total current Ic is controlled in such a way that it may not be lower than the min. value because ON-time of the voltage applied to the coils 1024 under an electrical energization control of the three-phase circuit 230 is increased.

In this case, when the motorcycle is started to operate by kicking the kick lever under a state in which the engine cannot be started to operate because the battery is completely discharged even if the engine key is turned, the electrical power generated through kicking at the kick lever is accumulated at an electrolysis capacitor, for example, and the limited electrical power accumulated in the electrolysis capacitor is supplied to each of the electrical component parts.

In the third preferred embodiment, the limited electrical power accumulated in the electrolysis capacitor by kicking at the kick lever can be fed to the electrical component parts such as an engine control device or the like required for starting the engine even under a state in which an amount of electrical power consumed by the fuel pump 1010 is restricted and the battery is completely discharged. This is because the PWM control is carried out in such a way that the total current Ic flowing in the coils 1024 does not exceed the predetermined max value. Accordingly, the engine of the motorcycle can be started to operate by kicking at the kick lever even under a state in which the battery is completely discharged.

In the third preferred embodiment, a controlling operation for limiting the maximum value of the total current Ic is effective even after starting the engine. Accordingly, it is possible to prevent an excessive current from flowing in the three-phase circuit 1230 and the electrical component parts of the three-phase circuit 1230 from being damaged by limiting the maximum value of the total current Ic even if the excessive current is fed to the three-phase circuit 1230 under a normal operation after starting the engine.

In addition, in the third preferred embodiment, it is possible to feed a current required for driving the fuel pump 1010 and keep an operation of the fuel pump 1010 because the PWM control is carried out in such a way that the total current Ic does not become lower than the predetermined minimum value under a normal operation after starting the engine.

In addition, in the third preferred embodiment, a manufacturing cost of the circuit module comprised of the three-phase circuit 1230, current detector 1240 and PWM control part 1250 can be reduced because the three-phase circuit 1230, current detector 1240 and PWM control part 1250 are constituted as one circuit module. In addition, they are constituted as one circuit module, the three-phase circuit 1230, current detector 1240 and PWM control part 1250 can be made compact and easily assembled.

Fourth Preferred Embodiment

In FIG. 12 is illustrated a flow-chart of the electrical energization control for the coils 1024 in accordance with the fourth preferred embodiment of the present invention. Substantially the same composing elements as those of the first preferred embodiment are denoted by the same reference symbols.

In the aforesaid third preferred embodiment, the PWM signal transmitted from the PWM control part 1250 to the control circuit 1212 is controlled by adding +1 to CT to reduce the PWM value when the total current Ic flowing in the coils 1024 exceeds the maximum value, and by adding −1 to CT and increasing the PWM value when the total current Ic becomes lower than the minimum value. To the contrary, in the fourth preferred embodiment, the PWM value is reduced by adding +1 to CT when the total current Ic exceeds the maximum value, and the PWM value is increased by adding −1 to CT when the total current Ic is decreased lower than the maximum value through judgment at the steps 1304, 1320 in FIG. 12, thereby the PWM signal transmitted from the PWM control part 1250 to the control circuit 1212 is controlled. That is, in the fourth preferred embodiment, the PWM value is increased or decreased with the maximum value being applied as an interface value.

In the aforesaid plurality of preferred embodiments, a fuel pump efficiency can be improved because the sliding resistance and the fluid resistance are reduced as compared with those of the commutator controlled motor by using the brushless motor as the driving source for the fuel pump. As a result, the fuel pump can be made compact in size and a low current can flow in it. Accordingly, the fuel pump can be easily mounted in the small-sized fuel tank of the motorcycle.

In addition, since the brushless motor is applied as a driving source, a problem of wear at the sliding portion between the commutator and the brush as found in the commutator controlled motor does not occur. With such an arrangement as above, it is possible to increase the number of rotation of the motor. In addition, a rate of leakage at the pump passage producing a reduction in pump efficiency is reduced through small-sized formation of the fuel pump. Accordingly, the fuel pump efficiency in a flow rate range of a small-sized motorcycle is improved by an arrangement in which the brushless motor is applied as a driving source, and as described in the first preferred embodiment, for example, a range of the impellor outer diameter D1 is set to 12.1 mm≦D1<26 mm to make a size of the fuel pump small.

In addition, a fuel discharging pressure is rapidly increased up to its predetermined pressure also when the fuel pump is started again to operate under a low voltage because the rated number of rotation can be increased.

In addition, a total amount of driving current fed to the coils 1024 can be set to 1 A or less through improvement of the fuel pump efficiency caused by a small diameter of the pump and its high speed rotation. With such an arrangement as above, a less-expensive element can be used as the power switching element 1214 of the control device 1210.

In addition, the control device 1210 for controlling a driving current fed to the coils 1024 is not installed in the fuel tank 1001, but installed, outside the fuel tank 1001, at the lid member 1002 closing an opening 101a of the fuel tank 1001. Since no control device is mounted in the fuel pump, it is possible to make a size of the fuel pump itself small and a size of a tank hole formed at the fuel tank for use in inserting the fuel pump small. Accordingly, the fuel pump 1010 can be mounted in the small-sized fuel tank 1001 of the motorcycle. In addition, the control device 1210 can be easily sealed because no fuel seal of the control device 1210 is required as compared with the case in which the control device 1210 is mounted in the fuel tank 1001.

In the aforesaid plurality of preferred embodiments, an interface distance between the coils 1024 and the fuel is elongated because the coils 1024 are resin molded. As a result, both electrical corrosion of the coils 1024 and corrosion can be prevented because a possibility that the coils 1024 and the fuel are contacted to each other can be reduced.

Other Preferred Embodiments

In the aforesaid first preferred embodiment, although the impellor outer diameter D1 is set to a range of 12.1 mm<D1<26 mm, the impellor outer diameter D1 of the fuel pump is not limited to the aforesaid range when the fuel pump can be mounted in the fuel tank of the motorcycle.

In addition, in the aforesaid plurality of preferred embodiments, although the fuel discharging amount required in the fuel pump is set to a range of 5 L/h or more to 30 L/h or less, the fuel discharging amount of the fuel pump is not limited to a range from 5 L/h or more to 30 L/h or less when the fuel pump is mounted in the fuel tank of the motorcycle requiring the fuel discharging amount other than the foregoing amount.

In addition, the fuel pump disclosed in the aforesaid plurality of preferred embodiments may be mounted in the fuel tank of the motorcycle where the engine displacement exceeds 150 cc.

In addition, if the fuel pump can be mounted in the fuel tank of the motorcycle, a total amount of driving current fed to the coils 1024 may exceed 1 A.

In addition, if the fuel pump can be mounted in the fuel tank of the motorcycle, the control device controlling the driving current fed to the coils 1024 may be mounted in the fuel tank or in the fuel pump.

In addition, in the aforesaid plurality of preferred embodiments, although the rotating position of the rotor is detected in reference to an inductive electromotive force generated at the coils 1024 not electrically energized, the rotating position of the rotor may be detected through utilization of the detector element such as a hole element and the like.

In the aforesaid plurality of preferred embodiments, the brushless motor is constituted while the coils 1024 are wound around the stator core 1020 at the outer circumference and the permanent magnets 1036 are mounted on the rotor 1030 at the inner circumference, the brushless motor can be constituted such that the coils are wound around the stator core at the inner circumference.

In addition, in the third and the fourth preferred embodiments, although the counter value is increased or decreased in reference to a result of comparison between the total current Ic flowing at the coils 1024, with the maximum value and minimum value or only with the maximum value, the corresponding PWM value is calculated. It may also be applicable that the counter is not used and the PWM value is calculated directly in reference to the result of comparison between the total current Ic, the maximum value and the minimum value and only with the maximum value. In addition, although the total current flowing at the coils 1024 is controlled with the PWM control, it may also be applicable that the total current flowing at the coils is controlled under a duty control.

In addition, in the third and the fourth preferred embodiments, although the total current flowing at the coils is controlled by increasing or decreasing ON-time of voltage applied to the coils 1024 with the PWM control, it may also be applicable that the total current flowing at the coils 1024 is controlled by increasing or decreasing the voltage value applied to the coils 1024 with the PWM control, as shown in FIG. 13.

In addition, in the third preferred embodiment, although the three-phase circuit 1230, current detector 1240 and PWM control part 1250 are constituted by one circuit module, it may also be applicable that each of them can be constituted as a different circuit module. With such an arrangement as above, the control device 1220 can be easily constituted by adding the current detector 1240 and the PWM control part 1250 constituting a circuit module different from the three-phase circuit 1230 to the existing three-phase circuit 1230.

In addition, in the third preferred embodiment, the upper limit value and the lower limit value of the total current flowing in the coils 1024 are always limited from after starting the engine to the normal operating time, the limitation of the lower limit value may be eliminated. In addition, in the third and the forth preferred embodiments, it may also be applicable that the upper limit value of the total current flowing at the coils 1024 is limited only in a predetermined time after starting the engine, and upon elapsing of the predetermined time, the current limitation can be released.

Fifth Preferred Embodiment

The fuel pump in accordance with the fifth preferred embodiment of the present invention is illustrated in FIGS. 14 to 16. A fuel pump 2010 is an in-tank type pump mounted in the fuel tank of a motorcycle, for example.

As shown in FIG. 14, the fuel pump 2010 comprises a pump 2012, a motor 2013 for rotationally driving an impellor 2020 of the pump 2012 and an end support cover 2028. A housing 2014 encloses the outer circumferences of the pump 2012 and the motor 2013, and this housing is a common housing for the pump 2012 and the motor 2013. The end support cover 2028 covers a side of the motor 2013 opposite to the pump 2012 and forms a fuel discharging port 2060.

The pump 2012 is a Wesco pump having a pump cover 2060, a pump casing 2018 and an impellor 2020. The pump cover 2016 and the pump casing 2018 are case members rotatably storing the impellor 2020 acting as the rotating member.

The impellor 2020 acting as the rotating member is formed into a disc-like member, and both sides of the outer circumferential edge of the impellor 2020 in a rotating shaft direction are formed with vane grooves. Pump passages 2022 are formed at both sides of the impellor 2020 in its rotating shaft direction by the vane grooves of the impellor 2020, the pump cover 2016 and the pump casing 2018.

Fuel sucked at the fuel inlet not shown of the pump cover 2016 under a rotation of the impellor 2020 repeatedly flows out of or flows into the vane grooves of the impellor 2020 in sequence and becomes a circulating flow. A fuel pressure in the pump passage 2020 is increased by energy of the fuel becoming this circulating flow. The fuel of which pressure is increased in the pump passage 2020 flows out of the fuel outlet not shown in the pump casing 2018, passes through the fuel passage 2062 formed between the inner circumferential surface of the stator core 2030 and the outer circumferential surface of the rotor 2050 and finally is discharged out of a discharging port 2060 formed at an end support cover 2028.

The motor 2013 is a brushless motor and comprises a stator core 2030, coils 2042 and a rotor 2050 or the like. As shown in FIG. 15, the stator core 2030 is constituted by arranging six cores 2022 in a circumferential direction. Each of the cores 2032 generates a magnetic pole at an opposing plane facing the rotor 2050 through electrical energization at the coils 2042. Each of the cores 2032 has outer circumferences 2034 and teeth 2036, it is constituted such that some magnetic steel plates having an insulating film coated thereon are stacked up in a rotating shaft direction and further it is constituted as one member. The outer circumferences 2034 are formed as arcuate shapes having an equal circumferential width, and the annular core is formed by six outer circumferences 2034. The teeth 2036 are protruded from the central part of the outer circumferences 2034 toward the rotor 2050 at the inner circumference. Each of resin insulators 2040 is fitted to each of the cores 2032 so as to space it apart from a winding space.

The coil 2042 is concentrically wound at the outer circumference of the insulator 2040 for every core 2032, and electrically connected to the coil terminal 2044 at the end support cover 2028 shown in FIG. 14. The coil terminal 2044 is fitted to a lead terminal 2045 electrically connected to the extremity end of the lead wire 2046 and is electrically connected to it. The lead wire 2046 is taken out of the end support cover 2028.

A magnetic pole generated at each of the coils 2042 is controlled by a switching of the driving current fed to the coil 2042 with a control device not shown. In order to perform a switching of the driving current fed to the coil 2042 and to rotate the rotor 2050, it is necessary to detect a rotating position of the rotor 2042. Then, it may also be applicable that the rotating position of the rotor 2050 is detected by a detector element such as a hole element or the like and the driving current is switched in response to this detecting signal. In addition, coils 2042 by two third of six coils 2042 are driven, the inductive electromotive force generated at one third coils 2042 not electrically energized is detected through rotation of the rotor 2050 and a rotating position of the rotor 2050 may be discriminated.

The insulation resin 2048 fixes the housing 2014, stator core 2030 and coils 2042 and at the same time holds a bearing 2026 supporting the shaft 2024 facing at the end support cover 2028.

The rotor 2050 has a shaft 2024, yoke 2052 and permanent magnet 2054, and the rotor 2050 is rotatably arranged at the inner circumference of the stator core 2030. The shaft 2024 is rotatably supported by the bearings 2026, 2027. As shown in FIG. 15, the permanent magnet 2054 is formed into a cylindrical member with one member and mounted at the outer circumference of the yoke 2052. The permanent magnet 2054 forms eight magnetic poles 2055 in a rotating direction. The eight magnetic poles 2055 are magnetically energized to form magnetic poles alternatively different from each other in a rotating direction at the outer circumferential surface facing the stator core 2030.

Then, a method for manufacturing the stator core 2030 and the coils 2042 will be described as follows.

As shown in FIG. 16, six cores 2032 having insulators 2040 fitted thereto are fixed to a jig and the like in such a way that their outer circumferences 2034 may be positioned inside. At this time, the coils 2042 are not yet formed. Then, the winding is concentrically wound at the outer circumference of the insulator 2040 for every core 2032 and as shown in FIG. 16, the coils 2042 are formed. Then, the coils 2042 and a coil terminal 2044 are electrically connected to each other.

In this way, six cores 2032 formed with coils 2042 are inserted into the housing 2014. At this time, the insulators 2040 are engaged with a protrusion 2015 (refer to FIG. 14) formed at the inner wall of the housing 2014, a position of the core 2032 in its rotating shaft direction is set and at the same time the core 2032 is prevented from dropping off the housing 2014. Then, the insulator resin 2048 is molded and the housing 2014, bearing 2026, core 2032, insulator 2040, coils 2042 and coil terminal 2044 are fixed. The insulator resin 2048 is molded to fix each of the members and at the same time fuel can be prevented from leaking out from the clearance between the cores 2032 of the stator core 2030 toward the housing 2014.

In the fifth preferred embodiment, the sliding resistance and the fluid resistance can be reduced as compared with those of the brushmotor because no sliding portion is found between the commutator and the brush and no groove for dividing the commutator into each of the segments by making the motor 2013 as a brushless motor using no commutator. With such an arrangement as above, the motor 2013 can be made small in its size and a low current can be attained under the same output because the motor efficiency of the motor 2013 is improved with the result that the pump efficiency of the fuel pump 2010 is improved.

No electrical corrosion or no poor electrical contact is produced at the sliding portion between the commutator and the brush as found in the brushmotor even if deteriorated fuel or low quality is used because the motor 2013 of the brushless motor does not use any commutator. Accordingly, it has a superior anti-corrosion characteristic. Further, a lifetime of the fuel pump 2010 is extended because no sliding wear occurs between the commutator and the brush.

Further, as compared with the distributed winding, a concentric winding prevents the windings from being crossed to each other at the coil ends and enables an occupying rate of the winding to be increased. As a result, an amount of winding wound around in the same winding space is increased as compared with that of the distributed winding for the motor having the same size and accordingly the motor efficiency is improved. In addition, if there are provided motors having the same output, the winding space is decreased as compared with that of the distributed winding and a size of the motor can be made small.

In addition, fuel lubricates the sliding portion among the rotor 2050, and bearings 2026 and 2037 because the fuel flows in a rotating shaft direction at the fuel passage 2062 formed between the stator core 2030 and the rotor 2050 in the motor 2013.

The same effects as those of the first preferred embodiment are generated in each of the preferred embodiments described below because as the motor, a brushless motor is used, the winding is concentrically wound at the stator core to form coils in the same manner as that of the fifth preferred embodiment.

Sixth Preferred Embodiment

The sixth preferred embodiment of the present invention is illustrated in FIGS. 17 and 18. The composing elements that are substantially the same as those of the fifth preferred embodiment are denoted by the same reference symbols.

A stator core 2076 shown in FIG. 17 comprises an annular outer circumference 2072 and six teeth 2076 protruded from the outer circumference 2072 toward the rotor 2050, wherein magnetic steel plates having an insulation film coated thereon are stacked up and the stator core is constituted by one member. Although the outer circumference 2072 is formed into an annular shape by arcuate portions 2073 connected to the adjoining two teeth 2076, and arcuate portions 2074 connected to one tooth 2076, the adjoining arcuate portions 2074 are discontinuous. Then, the arcuate portions are merely contacted at their discontinuous portions, wherein they are not fixed through welding and the like. The arcuate portions 2074 at the outer circumference 2072 are formed in the same width in a circumferential direction and they are curved toward the inner circumference.

Then, a method for manufacturing the stator core 2076 and the coils 2042 will be described as follows.

In FIG. 18A is shown a mother material 2080 for the stator core 2070 before the arcuate portions 2073, 2074 are bent. In FIG. 18A, the insulator 2040 is fitted to the tooth 2076, and a winding is concentrically wound around the outer circumference of the insulator 2040 to form the coils 2042.

Under a state before the arcuate portions 2073, 2074 before the coils 2042 are formed are bent, an angle that the arcuate portions 2073, 2074 and the tooth 2076 formed at the winding space for the coils 2042 is made large as compared with that after the arcuate portions 2073, 2074 are bent. Further, the arcuate portions 2073, 2074 are spaced apart farther from the tooth 2076 than an imaginary straight line 2200 crossing at a right angle with the tooth 2076 at the outer circumferential end 2077. Accordingly, the winding can be easily wound up to the outer circumferential end 2077 of the tooth 2076 without being prohibited by the arcuate portions 2073, 2074.

When the coils 2042 are formed by winding the windings, the arcuate portions 2073, 2074 are bent at the outer circumferential end 2077 of the tooth 2076 in a direction approaching to the tooth 2076, toward the inner circumference in FIG. 17 to attain the state shown in FIG. 18B. At this time, the contact portion between the arcuate portions 2074 acting as a non-continuous part of the annular outer circumference 2072 is not fixed. Accordingly, under a state shown in FIG. 18B, a force widened at the outer circumference may act on the stator core 2070.

Thus, the structure shown in FIG. 18B is press fitted into the housing 2014 and the insulation resin 2048 is molded there, the housing 2014, insulator 2040, coils 2042 and stator core 2070 are fixed. The insulation resin 2080 is molded to fix each of the members and at the same time it is possible to prevent fuel from leaking out of the clearance between the arcuate portions 2074 of the stator core 2070 to the housing 2014.

In the sixth preferred embodiment, the stator core 2070 formed by bending the arcuate portions 2073,2074 is press fitted into the housing 2014 to prevent the stator core 2070 from being expanded in the housing 2014 toward the outer circumference and to enable both position and orientation of the tooth 2076 to be prevented from being displaced. When the stator core 2070 is press fitted into the housing 2014, it is satisfactory that the outer circumferential surface of the housing 2014 is pressed with a jig and the like so as to prevent the housing 2014 from being deformed with the press fitting force.

In addition, since the stator core 2070 is press fitted into the housing 2014, it is possible to restrict an axial displacement between the housing 2014 and the stator core 2070. As a result, it is possible to make a uniform clearance between the rotor 2050 mounted at the inner circumference of the stator core 2070 and the stator core 2070 in a rotating direction.

In addition, since the stator core 2070 is press fitted into the housing 14, it is possible to prevent the stator core 2070 from dropping off the housing 2014 at the time of assembling work.

In the sixth preferred embodiment, since the arcuate portions 2073, 2074 are formed in an equal width in a circumferential direction, the winding space is widened up to a deep side of the outer circumferential end part 2077 of the tooth 2076 under a state where the arcuate portions 2073, 2074 are bent, i.e. a state shown in FIG. 18B. To the contrary, under the state in which the arcuate portions 2073, 2074, it is hard to wind the winding up to the deep part of the outer circumferential end 2077 of the tooth 2076 due to prohibiting by the arcuate portions 2073, 2074. Thus, in the sixth preferred embodiment, since a winding is wound under a state in which an angle formed at the winding space by the arcuate portions 2073, 2074 before the arcuate portions 2073, 2074 are bent and the tooth 2076 is large as compared with a state after the arcuate portions 2073, 2074 are bent, the winding is not prohibited by the arcuate portions 2073, 2074 and the winding can be easily wound up to the outer circumferential end 2077 of the tooth 2076.

In addition, since the mother material 2080 is formed by one member, mere bending of the arcuate portions 2073, 2074 after winding the coils 2042 enables the stator core 2070 to be easily formed.

Seventh Preferred Embodiment

The seventh preferred embodiment of the present invention is shown in FIGS. 19 and 20. The composing elements that are substantially the same as those of the fifth preferred embodiment are denoted by the same symbols.

The stator core 2090 shown in FIG. 19 comprises an outer circumferential core 2092 and six coil cores 2094 protruded from the outer circumferential core 2092 toward the rotor 2050 separate from the outer circumferential core 2092. The outer circumferential core 2092 and the coil core 2094 are formed such that the magnetic steel plates having insulator film coated thereto are stacked up. The coils 2042 and the coil core 2094 are insulated by the insulation resin 2048.

Then, in FIGS. 20A and 20B is shown a method for manufacturing the stator core 2090 and the coil 2042.

Six coil cores 2094 are fixed to a jig and the like and mounted at a position shown in FIG. 20A. Under this state, the coil 2042 and the insulation resin 2048 are not formed. Then, six coil cores 2094 are molded with the insulation resin 2048 and fixed. This insulation resin 2048 prevents a short-circuit between the coil 2042 and the coil core 2094. Then, a winding is wound around the coil core 2094 molded with resin to form the coil 2042.

A structure shown in FIG. 20A that is formed in this way is assembled to the inner circumference of the outer circumferential core 2092 to form the stator core 2090.

In the seventh preferred embodiment, the outer circumferential core 2092 and the coil core 2094 are formed by separate members to enable the winding to be wound around each of the coil cores 2094 under a state before being assembled to the outer circumferential core 2092. With such an arrangement as above, the winding can be easily wound up to the outer circumferential core end of the coil core 2094 without being prohibited by the outer circumferential core 92.

In addition, in the seventh preferred embodiment, the insulation resin 2048 is molded before forming the coil 2042 to fix the coil core 2094 and the outer circumference of the fuel passage 2062 is covered by the insulation resin 2048. Further, since the outer circumferential core 2092 is formed into a continuous cylindrical shape, it is possible to prevent the fuel from leaking from the stator core 2090 to the housing 2014 without being molded with resin under a state in which the stator core 2090 is assembled in the housing 2014.

Eighth Preferred Embodiment

In FIGS. 21 and 22 is illustrated the eighth preferred embodiment of the present invention. The composing elements that are substantially the same as those of the fifth preferred embodiment are denoted by the same reference symbols.

A stator core 2100 shown in FIG. 21 comprises an outer circumferential core 2102, and six coil cores 2106 protruded from the outer circumferential core 2102 toward the rotor 2050 and separate from the outer circumferential core 2102. The outer circumferential core 2102 and the coil core 2106 are formed while the magnetic steel plates having insulation film coated thereon are stacked up.

Cavities 2104 are formed at the inner circumferential wall of the outer circumferential core 2102 in an equal angular spaced-apart relation in a circumferential direction over an entire length of the rotating shaft direction. A cross section of each of the cavities 2104 crossing at a right angle with the rotating shaft is a shape widened toward the bottom side. Protrusions 2108 are formed at the end of the outer circumferential core 2102 of the coil core 2106 over the entire length in the rotating shaft direction. A cross section of each of the protrusions 2108 crossing at a right angle with the rotating shaft is a shape widened toward its extremity end. The cavities 2104 of the outer circumferential core 2102 and the protrusions 2108 of each of the coil cores 2106 are fitted to each other to cause the outer circumferential core 2102 and the coil core 2106 to be connected to each other.

In FIGS. 22A and 22B is shown a method for manufacturing the stator core 2100 and coils 2042.

As shown in FIG. 22B, the insulators 2110 are fitted to the coil cores 2106 and windings are concentrically wound around the outer circumferences of the insulators 2110 to form coils 2042. In this case, FIG. 22B shows an arrangement in which the coil cores 2106 having the coils 2042 concentrically wound are assembled to the outer circumferential cores 2102, and it is not necessary to wind the windings under a state in which the coil cores 2106 are arranged and it is also applicable that the coil cores 2106 are attached to a jig one by one to wind the windings.

Then, they are fitted while the protrusions 2108 of the coil cores 2106 having the coils 2042 wound around are being inserted into the cavities 2104 of the outer circumferential cores 2102 shown in FIG. 22A from one of the rotating shaft directions to form the stator cores 2100.

In the eighth preferred embodiment, the outer circumferential cores 2102 and the coil cores 2106 are separately made to enable the windings to be easily wound up to a location near the protrusions 2108 of the outer circumferential core ends of the coil cores 2106 without being prohibited by the outer circumferential cores 2102.

Other Preferred Embodiments

In the aforesaid sixth preferred embodiment, although the stator core 2070 comprised of the outer circumference 2072 and the arcuate portions 2073, 2074 is constituted by one member, it may also be applicable that the stator core is formed by assembling a plurality of structures having the outer circumference 2072 divided into a plurality of segments in a circumferential direction and having the arcuate portion connected to at least one tooth outer circumferential end bent in a direction approaching to the tooth at the outer circumferential end.

In addition, in the fifth and sixth preferred embodiments, although the insulation resin 2048 is molded after the stator core is assembled into the housing 2014, it may also be applicable that the insulation resin 2048 is molded before assembling the stator core into the housing 2014 so as to fix the coils 2042 and the stator core.

In the aforesaid plurality of preferred embodiments except the seventh preferred embodiment, resin insulator is fitted to the coil cores to prevent an electrical short-circuited state among the coils 2042 and the stator core, it may also be applicable that insulating powder is applied to coat on the coil cores in place of fitting the insulator.

In the aforesaid plurality of preferred embodiments, the windings are concentrically wound around the stator core to form coils, the rotor having permanent magnets is mounted at the inner circumference of the stator core to constitute a brushless motor. To the contrary, it may also be applicable that a stator core forming the coil by concentrically winding the windings is mounted at the inner circumference of the rotor having permanent magnets to constitute a brushless motor.

In the aforesaid plurality of preferred embodiments, the stator core can be assembled into the housing 2014 either through press fitting or insertion work.

Ninth Preferred Embodiment

In FIGS. 23 and 24 is shown fuel supply equipment in accordance with the ninth preferred embodiment of the present invention. Fuel supply equipment 3002 is fixed to the bottom wall of the fuel tank 3001 of a motorcycle.

The fuel supply equipment 3002 has a lid member 3010, fuel pump 3020, suction filter 3070 and sender gauge 3072 and the like. The lid member 3010 is made of polyacetal or polyphenylene sulfide (PPS) into a disc shape so as to close an opening 3001a formed at the bottom wall of the fuel tank 3001. A discharging pipe 3011, connector 3012, connecting part 3013, fuel passage 3014 and electrical path 3016 or the like are integrally molded with resin at the lid member 3010. Then, the fuel pump 3020 is mounted in a lateral orientation at the bottom part of the fuel tank 3001 along the lid member 3010.

A discharging pipe 3011 feeds fuel discharged by the fuel pump 3020 outside the fuel tank 3001. The suction filter 3070 is snap coupled to the connecting part 3013. The fuel passage 3014 and the electrical path 3016 are arranged to protrude from the lid member 3010 above the fuel tank 3001. The fuel passage 3014 is connected to a discharging port 3066 of the fuel pump 3020 (refer to FIG. 25) by the fuel pipe 3015 so as to feed fuel discharged by the fuel pump 3020 to the discharging pipe 3011.

A terminal 3017 is mounted at a protruding end of the electrical path 3016. The terminal 3017 is electrically connected to electrical devices such as the fuel pump 3020 and the sender gauge 3072 or the like through the lead wire 3018 and further electrically connected to a connector 3012 mounted outside the fuel tank 3001 of the lid member 3010 through the electrical path 3016.

It is desirable that the terminal 3017 is mounted above the fuel tank 3001 rather than at the lid member 3010 and further above the fuel tank 3001 rather than the end part of the fuel pump 3020 at the bottom side of the fuel tank 3001. In this preferred embodiment, the terminal 3017 is mounted at a substantial same height as that of the end part of the fuel pump 3020 above the fuel tank 3001.

The fuel pump 3020 is supported by the lid member 3010 while the discharging port 3066 is connected to the fuel passage 3014 through a fuel pipe 3015 and then the suction filter 3070 snap fitted and connected to the coupling part 3013 and the intake port 3060 (refer to FIG. 25) are connected, and then mounted in the fuel tank 3001.

The suction filter 3070 extends in substantially the same direction as that where the fuel pump 3020 is mounted in a lateral orientation outside the lid member 3010 along the lid member 3010. With such an arrangement as above, the suction filter 3070 assures a filter area required for removing some foreign materials in the fuel sucked by the fuel pump 3020.

The sender gauge 3072 is connected to a float 3074 by an arm 3073 and outputs a position of the float 3074 moved up and down in response to a residual amount of fuel in the fuel tank 3001 as a fuel residual amount signal. As shown in FIGS. 23 and 24, the suction filter 3070 and the arm 3073 extend outside the lid member 3010 along substantially the same direction as the direction where the fuel pump 3020 is mounted in a lateral orientation along the lid member 3010 under a state where the fuel supply equipment 3002 is fixed to the fuel tank 3001.

Next, the fuel pump 3020 will be described in detail with reference to FIG. 25.

The fuel pump 3020 is provided with a motor 3022, and a pump 3023 driven through a rotation of the rotor 3040 of the motor 3022 for increasing a pressure of sucked fuel.

The motor 3022 acting as an electrical driving part is a so-called brushless motor and has a stator core 3030, coil 3032 and rotor 3040. The stator core 3030 is made such that some magnetic steel plates are stacked up in an axial direction and six teeth protruding toward the center of the motor 3022 are formed in a circumferential equal spacing. Coils 3062 are wound around each of the teeth. A resin housing 3024 molds the stator core 3030 and the coils 3032. A metallic housing 3026 is inserted and formed at the resin housing 3024 to press fit a suction side cover 3050 to be described later. Resin in the resin housing 3024 is filled in a plurality of through-holes 3026a arranged at the metallic housing 3026.

The rotor 3040 has a shaft 3042, a rotating core 3044 and permanent magnet 3046, and the rotor is rotatably installed at the inner circumference of the stator core 3030. The shaft 3042 acting as a rotating shaft is supported by the bearings 3027 at its both axial ends. The permanent magnet 3046 is formed into a cylindrical shape by one member and is mounted at the outer circumference of the rotating core 3044. The permanent magnet 3046 is made such that eight magnetic poles 3047 are formed in a rotating direction. Eight magnetic poles 3047 are magnetically energized at the outer circumferential surface facing the stator core 3030 so as to form different magnetic poles to each other in a rotating direction.

The pump 3023 is a so-called Wesco pump having a suction side cover 3050, discharging side cover 3052 and impellor 3054. The suction side cover 3050 and discharging side cover 3052 are case members rotatably storing the impellor 3054 acting as a rotating member. The discharging side cover 3052 is held by the metallic housing 3026 between the resin housing 3024 and the suction side cover 3050. The suction side cover 3050 and the discharging side cover 3052 form pump passages 3062, 3064 at both axial sides of the impellor 3054 along the vane grooves of the impellor 3054 to be described later. The fuel sucked at the suction port 3060 into the pump passages 3062, 3064 is increased in its pressure through rotation of the impellor 3054. Fuel of which pressure is increased by the pump passages 3062, 3064 is discharged out of a fuel outlet not shown of the discharging side cover 3052, passes between the stator core 3030 and the rotor 3040 and is discharged out of the discharging port 3066.

Next, a step of fixing the fuel supply equipment 3002 to the fuel tank 3001 is indicated in FIGS. 26A and 26B. As shown in FIG. 26A, the fuel supply equipment 3002 is inserted into the opening 3001a from a direction where the fuel pump 3020, suction filter 3070 and arm 3073 are arranged along the lid member 3010. Then, the fuel supply equipment 3002 is rotated as indicated by an arrow X in FIG. 26A at a location where the suction filter 3070 and the arm 3073 substantially extending outside the lid member 3010 along the lid member 3010 enter into the fuel tank 3001. Then, as shown in FIG. 26B, the opening 3001a is closed by the lid member 3010.

In accordance with the fuel supply equipment 3002 of the preferred embodiment described above, the fuel pump 3020 is mounted in the fuel tank 3001 and the fuel flows in the fuel pump 3020, so that a seal structure in the fuel pump 3020 is simple. In addition, the sliding resistance and the sliding wear can be reduced because the sliding portion among the shaft 3042 in the fuel pump 3020 and the bearings 3027 is lubricated with fuel.

In addition, an electrical short-circuited state of the motor 3022 can be prevented even if the fuel pump 3020 is mounted in a lateral orientation along the lid member 3010 at the bottom part in the fuel tank 3001 and the motor 3022 is immersed in the water accumulated at the bottom part in the fuel tank 3001 because the motor 3022 of the fuel pump 3020 is a brushless motor.

In addition, the height of the fuel pump 3020 in the fuel tank 3001 becomes low and the lid member 3010 and the fuel pump 3020 can be approached to each other because the fuel pump 3020 is mounted in a lateral orientation at the bottom part in the fuel tank 3001 along the lid member 3010. Accordingly, it is possible to support the fuel pump 3020 by a simple structure and mount the fuel pump 3020 in the fuel tank 3001 by connecting the discharging port 3066 of the fuel pump 3020 to the fuel passage 3014 through the fuel pipe 3015 and by connecting the suction port of the fuel pump 3020 to the suction filter 3070 snap fitted to the connecting part 3013.

Further, a height of each of the component parts of the fuel supply equipment 3002 including the fuel pump 3020 mounted in the fuel tank 3001 and a height of the fuel supply equipment are made low because the fuel pump 3020 is mounted in a lateral orientation in the fuel tank 3001 along the lid member 3010. Accordingly, entire fuel supply equipment 3002 is made compact.

In addition, other component parts including the fuel pump 3020 other than the lid member 3010 can be mounted in the fuel tank 3001 even through the small opening 1a if the fuel supply equipment 3002 is rotated while the fuel pump 3020, suction filter 3070, arm 3073 of the sender gauge 3072 and float 3074 are being inserted at the opening 3001a of the fuel tank 3001 in such a direction as one where the fuel pump 3020 along the lid member 3010 is mounted in a lateral orientation in the fuel tank 3001. This is because the suction filter 3070 and the arm 3073 of the sender gauge 3072 are mounted to extend outside the lid member 3010 in the same direction as the direction where the fuel pump 3020 is mounted in a lateral orientation along the lid member 3010. A strength of the fuel tank 3001 is improved due to a decreased size of the opening 3001a.

In addition, it is possible to prevent the terminal 3017 from being immersed in the water even if the fuel pump 3020 is almost immersed in the water accumulated at the bottom part in the fuel tank 3001 because the terminal 3017 is mounted away above the fuel tank 3001 rather than from the end part of the fuel pump 3020 at the bottom side of the fuel tank 3001 and mounted at substantially the same height as that of the end part of the fuel pump 3020 above the fuel tank 3001.

In addition, it is possible to supply a requisite electrical power to the fuel pump 3020 also when a battery capacity is low as found in that used in a motorcycle because the brushless motor having a higher fuel pump efficiency as compared with that of the brushmotor is used as the motor 3022 of the fuel pump 3020. In addition, it is possible to prevent any electrical poor conduction from being generated because no electrical corrosion or corrosion is produced at the sliding portion between the commutator and the brush as found in the brush motor even if deteriorated fuel or low quality fuel including alcohol, for example, is used due to the fact that the brushless motor has no sliding portion between the brush and the commutator as found in the brush motor. In addition, a lifetime of the fuel pump 3020 is extended because no sliding wear is generated between the commutator and the brush.

Other Preferred Embodiments

Although the fuel supply equipment is fixed to the bottom wall of the fuel tank of a motorcycle in the aforesaid preferred embodiments, it is desirable to employ the configuration of the present invention when the fuel supply equipment is mounted in the fuel tank and the fuel pump is mounted at the bottom part in the fuel tank whatever type of fuel tank other than that for the motorcycle may be applied.

Although in the aforesaid preferred embodiments, the brushless motor is constituted by winding the coils 3032 around the stator core 3030 at the outer circumference and by mounting the permanent magnet 3046 at the rotor 3040 at the inner circumference, it may also be applicable that the brushless motor is constituted by mounting the permanent magnet to the rotor at the outer circumference and by winding the coils around the stator core at the inner circumference.

Number	Date	Country	Kind
2004-110164	Apr 2004	JP	national
2004-266739	Sep 2004	JP	national
2004-327367	Nov 2004	JP	national
2004-355575	Dec 2004	JP	national

Fuel pump, fuel supply equipment using fuel pump and method for manufacturing fuel pump

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