JP2013199844A - Electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pump for supplying water and oil in a lightweight and inexpensive structure.SOLUTION: A shaft 3 fittedly inserted into a water pump chamber 2a, a motor chamber 2b, and an oil pump chamber is rotatably supported inside a housing 2. A motor 5 for rotating the shaft 3 is stored in the motor chamber 2b. An impeller 4 is fixed to the shaft 3 so as to be rotated together, and stored in the water pump chamber 2a. An inner rotor 6 is fixed to the shaft 3 so as to be rotated together, and stored in the oil pump chamber. In the water pump chamber 2a and the oil pump chamber, maximum values of periodical pressure fluctuations occurring when water and oil are sucked and discharged by the rotating motions of the impeller 4 and the inner rotor 6 are set so as to be displaced from each other.

Description

  The present invention relates to an electric pump for a vehicle including both a water pump for supplying water and an oil pump for supplying oil.

  In recent years, an increasing number of vehicles have a so-called idling stop function for stopping an engine during idling for the purpose of saving fuel and reducing exhaust gas. If the water pump that supplies water to the engine and the heater core in the vehicle has a structure that is driven in synchronization with the engine drive as in the conventional vehicle, the water pump stops together with the engine when idling is stopped. As a result, it becomes necessary to provide an auxiliary electric water pump that does not synchronize with the engine drive so that water is always supplied to the heater core even if the engine is stopped. is there. Also, in an oil pump that supplies oil to an automatic transmission, if the structure is such that it is driven in synchronism with the engine as in a conventional vehicle, it stops with the engine and the hydraulic pressure inside the transmission is set to a predetermined value. Since the transmission cannot be controlled instantaneously when the engine is restarted, the auxiliary pressure that does not synchronize with the engine drive is always maintained even if the engine is stopped. It is necessary to provide an electric oil pump.

  For example, the electric pump for a vehicle of Patent Document 1 includes a housing in which an oil pump chamber, a water pump chamber, and a motor chamber are formed in series, and the oil pump chamber, the water pump chamber, and the motor chamber are provided inside the housing. A shaft to be inserted is rotatably supported. A motor for rotating the shaft is attached to one end side of the shaft and is accommodated in the motor chamber. Further, first and second impellers are fixed to the middle and the other end of the shaft so as to rotate together, and the first and second impellers are accommodated in the water pump chamber and the oil pump chamber, respectively. . Then, by rotating the first and second impellers synchronized with the rotation of the shaft, each blade of the first impeller periodically sucks and discharges water from the water pump chamber, and the second impeller. Each of these blades periodically sucks and discharges oil from the oil pump chamber.

JP-A-2005-147127 (paragraphs 0010 to 0012, FIG. 1)

  By the way, as described above, in the electric pump that sucks and discharges the fluid in the pump chamber by rotating the rotating body by the rotation operation of the shaft, due to the pressure fluctuation of the pump chamber when the suction and discharge are repeated, Since periodic drive torque is generated, it is necessary to set the required torque of the motor that rotates the shaft based on the maximum value of the drive torque.

  However, since the electric pump of Patent Document 1 is configured to supply water and oil by rotating two impellers with one shaft, each impeller generates a periodic driving torque on the shaft. Therefore, if the maximum value of the drive torque generated by each impeller overlaps, the required torque of the motor that rotates the shaft must be set from the composite value of the overlapped drive torque, and the motor becomes larger and the electric As the weight of the pump increases, the manufacturing cost increases.

  The present invention has been made in view of such a point, and an object of the present invention is to provide an electric pump that rotates two rotating bodies with one shaft to supply water and oil, and is lightweight, The purpose is to provide a low-cost structure.

  In order to achieve the above object, the present invention is characterized in that the timings of pressure fluctuations in the water pump chamber and the oil pump chamber generated by the rotating operation of the two rotating bodies are shifted.

  That is, in the first invention, a water pump chamber, an oil pump chamber, and a motor chamber are formed in series, and are rotatably supported inside the housing, and the water pump chamber, the oil pump chamber, and the motor chamber are fitted therein. A shaft to be inserted, a motor that is housed in the motor chamber and rotates the shaft, and is integrally fixed to the shaft and housed in the water pump chamber, and periodically sucks and discharges water by a rotating operation. A first rotating body, and a second rotating body that is fixed to the shaft so as to rotate and is accommodated in the oil pump chamber and that periodically sucks and discharges oil by a rotating operation, and includes the water pump chamber and the oil In the pump chamber, periodic pressure fluctuations respectively generated by the suction and discharge of water and oil by the rotating operation of the first and second rotating bodies. Wherein the maximum value of is set to be shifted from each other.

  In a second invention, in the first invention, the first rotating body is an impeller in which a plurality of blades are provided at equal intervals around the shaft, and the second rotating body has a plurality of external teeth on the outer periphery. A spur gear-shaped inner rotor formed on the outer periphery of the oil pump chamber. The rotor is accommodated, and the blades and the external teeth are set to the same number so that the number of pressure fluctuations per rotation of the impeller and the inner rotor is the same. The timing when the tip of the blade reaches the maximum value of the pressure fluctuation in the water pump chamber immediately after passing the water discharge portion in the water pump chamber, and the suction and discharge of oil in the oil pump chamber Minute opening area becomes the minimum, characterized in that the timing at which the maximum value of the pressure variation of the oil pump chamber is set to be shifted from each other.

  According to a third invention, in the first or the second invention, the motor is fixed around the shaft with one of a plurality of magnets having a plurality of coils and a plurality of magnetic poles as a rotor, and rotated with the other as a stator. It is arranged around the child and is configured to rotate the shaft by the magnetic action of each coil and magnet, and the least common multiple of the number of coils and the number of magnetic poles of the magnet is the first and second rotations. A torque ripple that is an integral multiple of the number of pressure fluctuations per revolution of the body, and the position of each coil and each magnetic pole around the shaft is periodically generated by the least common multiple by the magnetic action of each coil and magnet. The timing when the maximum value of the timing is the maximum value of the maximum value periodically generated in the combined value of the pressure fluctuation of the water pump chamber and the pressure fluctuation of the oil pump chamber Characterized in that it is configured to match the.

  In the first aspect of the invention, when the pressure of the water pump chamber is maximized during operation of the electric pump, the pressure of the oil pump chamber is not maximized, and the maximum driving torque generated in the shaft by the rotation of the first rotating body is achieved. And the timing at which the driving torque generated in the shaft is maximized due to the rotation of the second rotating body. Accordingly, the required torque of the motor for rotating the shaft can be reduced as compared with the case where each driving torque generated on the shaft by the first and second rotating bodies overlaps at the maximum value, and the motor is downsized to reduce the weight of the electric pump. And cost reduction can be realized.

  In the second aspect of the invention, the portion for sucking and discharging water is constituted by a water pump made of an impeller, and the portion for sucking and discharging oil is an internal gear pump made of an inner rotor and an outer rotor. Since it is configured, it is possible to provide an electric pump that has a relatively simple structure, is unlikely to fail, and is easy to maintain.

  In the third invention, when the electric pump is operated, the maximum timing of the torque ripple that is periodically generated by the magnetic action of the magnet and each coil is periodically applied to the shaft by the rotational operation of the first and second rotating bodies. This coincides with the maximum timing of the combined torque of the driving torques generated in the above. Therefore, the shaft can be rotated with the minimum required torque, and the motor can be downsized to reliably achieve the weight reduction and cost reduction of the electric pump.

It is sectional drawing of the electric pump which concerns on embodiment of this invention. (A) is sectional drawing in the AA line of FIG. 1, (b) is sectional drawing in the BB line of FIG. 1, (c) is sectional drawing in the CC line of FIG. It is sectional drawing which the shaft of the electric pump rotated 15 degree | times from the state of FIG. 2, and shows the state which the pressure of the water pump chamber was the maximum and the torque ripple of the motor became the minimum. It is sectional drawing which the shaft of the electric pump rotated 15 degree | times from the state of FIG. FIG. 5 is a cross-sectional view of the shaft of the electric pump rotated 15 degrees from the state of FIG. 4, showing a state where the pressure in the oil pump chamber is maximum and the torque ripple of the motor is maximum. It is a wave form diagram which shows the relationship between the torque ripple which generate | occur | produces each driving torque which generate | occur | produces in a shaft by each of the water pump part and oil pump part of an electric pump, the synthetic value of each driving torque, and rotation of a motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature.

  FIG. 1 shows an electric pump 1 according to an embodiment of the present invention. The electric pump 1 supplementarily supplies water to the heater core of the vehicle and simultaneously supplies oil to the automatic transmission, and is attached to a fixed side of the vehicle (not shown).

  The electric pump 1 includes a substantially cylindrical iron housing 2 and a shaft 3 rotatably supported in the housing 2, and the shaft 3 extends in the central axis direction of the housing 2.

  Inside the housing 2, a water pump chamber 2a, a motor chamber 2b, and an oil pump chamber 2c are arranged in series from one end side (left end side in FIG. 1) to the other end side (right end side in FIG. 1). The shaft 3 is inserted into the water pump chamber 2a, the motor chamber 2b, and the oil pump chamber 2c.

  The motor chamber 2b includes a concave first space 20a that opens to the water pump chamber 2a side, and an annular second space 20b that is formed around the first space 20a.

  In the middle of the shaft 3 in the longitudinal direction, a substantially cylindrical magnet (rotor) 51 having a pair of magnetic poles 51a and 51b sandwiching the shaft 3 is fixed integrally with the first shaft 51. It is accommodated in the space 20a.

  The gap S formed between the inner peripheral wall of the first space 20a and the magnet 51 is filled with water in the water pump chamber 2a, and the magnet 51 contains water in the gap S. It is supposed to be cooled by.

  In the second space 20b, as shown in FIGS. 2 to 5, three coils 52 as the stator 50 are arranged around the shaft 3 at equal intervals.

  The motor 51 is constituted by the magnet 51 and the three coils 52, and the shaft 3 is rotated by the magnetic action of the magnet 51 and each coil 52.

  An annular bulging portion 22 that bulges radially outward is formed at a portion of the housing 2 corresponding to the water pump chamber 2a.

  A small-diameter cylindrical portion 21 having a communication hole 21a communicating with the water pump chamber 2a is integrally projected at the center of one end in the central axis direction of the housing 2, and the tip of the cylindrical portion 21 is Opened and connected to a water supply tank (not shown).

  As shown in FIGS. 2 to 5, the peripheral wall of the annular bulging portion 22 has a shape that gradually separates from the central axis of the shaft 3 as it goes to one side around the central axis of the shaft 3, and its upper end portion. Is formed with a water discharge port 22a that opens on one side around the central axis of the shaft 3.

  An impeller (first rotating body) 4 that functions as a water pump is fixed to one end of the shaft 3 in the longitudinal direction (left end side in FIG. 1) and is integrally fixed to the water pump chamber 2a. The six blades 4a are provided around the shaft 3 at equal intervals.

  Then, due to the rotation operation of the impeller 4 accompanying the rotation of the shaft 3, water is sucked from the opening of the cylindrical portion 21 through the communication hole 21a into the water pump chamber 2a, and as shown in FIG. While rotating and moving as indicated by an arrow X1, the water pump chamber 2a is pressurized and discharged from the water discharge port 22a.

  That is, the impeller 4 periodically sucks and discharges water from the water pump chamber 2a by a rotating operation, and the water pump chamber is rotated by the number of blades 4a per rotation of the impeller 4. There is a pressure fluctuation in 2a.

  The oil pump chamber 2c accommodates an inner rotor (second rotating body) 6 and an outer rotor 7 that function as an oil pump.

  As shown in FIGS. 2 to 5, the inner rotor 6 has a spur gear shape that is integrally fixed to the other end in the longitudinal direction of the shaft 3 (near the right end in FIG. 1). Six external teeth 6a, which is the same number as the number of blades 4a of the impeller 4, are formed at equal intervals.

  The outer rotor 7 has an annular shape with seven inner teeth 7 a formed on the inner peripheral surface, and an oil compression chamber Pr is formed between the inner teeth 7 a and the outer teeth 6 a of the inner rotor 6. As described above, the inner rotor 6 is meshed with the rotational axis shifted.

  Further, on the other end side in the central axis direction of the housing 2 (right end side in FIG. 1), an oil discharge portion 8a and an oil that open into the oil pump chamber 2c in a substantially semicircular shape when viewed from the central axis direction of the shaft 3. The suction part 8b is formed symmetrically up and down.

  The oil is sucked into the compression chamber Pr from the oil suction portion 8b by the rotation operation of the inner rotor 6 accompanying the rotation of the shaft 3, and moves as indicated by an arrow X2 in FIG. Pressurized in the compression chamber Pr and discharged from the oil discharge portion 8a.

  That is, the inner rotor 6 and the outer rotor 7 are configured to periodically suck and discharge the oil in the compression chamber Pr by a rotating operation, and the inner rotor 6 and the outer rotor 7 are as many as the outer teeth 6 a of the inner rotor 6. 6, pressure fluctuation occurs in the oil pump chamber 2c per one rotation.

  The positions of the blades 4a of the impeller 4 and the outer teeth 6a of the inner rotor 6 around the shaft 3 are immediately after the tips of the blades 4a pass through the water discharge ports 22a in the water pump chamber 2a (FIG. 3). The timing at which the pressure fluctuation of the water pump chamber 2a reaches the maximum value (see (a)) and the opening areas of the oil discharge portion 8a and the oil suction portion 8b in the oil pump chamber 2c are minimized (FIG. 6C). ) Reference) The timing at which the maximum value of pressure fluctuation in the oil pump chamber 2c is set to be shifted from each other by a half cycle.

  That is, in the water pump chamber 2a and the oil pump chamber 2c, the maximum values of the periodic pressure fluctuations generated by the suction and discharge of water and oil due to the rotating operation of the impeller 4 and the inner rotor 6 are set so as to deviate from each other. Has been.

  Further, the torque ripple of the motor 5 is 6 times which is the least common multiple of the number of magnetic poles of the magnet 51 and the number of coils 52 per one rotation of the shaft 3 due to the magnetic action of the magnet 51 and each coil 52. The position around the shaft 3 of the magnet 51 and each coil 52 is generated at the timing when the maximum value of the torque ripple is a period in the combined value of the pressure fluctuation of the water pump chamber 2a and the pressure fluctuation of the oil pump chamber 2c. It is set so as to coincide with the timing of the maximum value generated automatically.

  Next, the relationship between each torque applied to the shaft 3 per one rotation of the motor 5 and the required torque of the motor 5 will be described.

  FIG. 6 is a graph in which the horizontal axis represents the rotation angle of the motor 5 and the vertical axis represents the torque value. D1 represents data of driving torque applied to the shaft 3 due to pressure fluctuations in the water pump chamber 2a, and D2 represents oil. Data of driving torque applied to the shaft 3 due to pressure fluctuation in the pump chamber 2c is shown, D3 shows data of combined torque obtained by combining the two driving torques, and D4 shows data of torque ripple generated by the rotation of the motor 5. Show.

  As shown in FIG. 6, the maximum timing of the combined torque of the drive torques generated periodically coincides with the maximum torque ripple value, so that the shaft 3 can be driven with the minimum required torque. Can be rotated.

  Next, the operation state of the electric pump 1 will be described in time series.

  FIG. 2 shows a state in which the pressure in the water pump chamber 2a increases and the pressure in the oil pump chamber 2c and the torque ripple decrease during the operation of the electric pump 1 (see the position of arrow D in FIG. 6). ).

  From the state shown in FIG. 2, when the impeller 4, the magnet 51, and the inner rotor 6 rotate 15 degrees in synchronization with the rotation of the shaft 3, as shown in FIG. 3A, one tip of the blade 4a. Immediately after passing through the water discharge port 22a in the water pump chamber 2a, the pressure fluctuation in the water pump chamber 2a becomes the maximum value, and as shown in FIG. 3C, the oil in the oil pump chamber 2c The opening area of the discharge part 8a and the oil suction part 8b becomes the maximum, the pressure fluctuation of the oil pump chamber 2c becomes the minimum value, and the torque ripple value becomes the minimum (see the position of arrow E in FIG. 6).

  Next, when the impeller 4, the magnet 51, and the inner rotor 6 are further rotated 15 degrees from the state shown in FIG. 3, the pressure in the water pump chamber 2a is reduced as shown in FIG. The pressure and torque ripple in the oil pump chamber 2c increase (see the position of arrow F in FIG. 6).

  When the impeller 4, the magnet 51, and the inner rotor 6 are further rotated 15 degrees from the state shown in FIG. 4, the water discharge port 22a is formed between the tips of the two blades 4a as shown in FIG. As shown in FIG. 5 (c), the pressure variation in the water pump chamber 2a is minimized, and the opening areas of the oil discharge portion 8a and the oil suction portion 8b in the oil pump chamber 2c are minimized. Thus, the pressure fluctuation in the oil pump chamber 2c becomes the maximum value, and further, the torque ripple value becomes the maximum (see the position of the arrow G in FIG. 6).

  As described above, the impeller 4, the magnet 51 and the inner rotor 6 rotate in synchronization with the rotation of the shaft 3, whereby the pressure fluctuation in the water pump chamber 2 a and the oil pump chamber 2 c and the torque ripple in the motor 5 are changed. Periodically occurs.

  As described above, according to the embodiment of the present invention, when the pressure of the water pump chamber 2 a becomes maximum when the electric pump 1 is operated, the pressure of the oil pump chamber 2 c does not become maximum, and the shaft 3 is rotated by the rotation of the impeller 4. The timing at which the drive torque generated at the maximum is generated differs from the timing at which the drive torque generated at the shaft 3 by the rotation of the inner rotor 6 is maximized. Therefore, the required torque of the motor 5 for rotating the shaft 3 can be reduced as compared with the case where the drive torques generated on the shaft 3 by the impeller 4 and the inner rotor 6 are overlapped at the maximum value. The pump 1 can be reduced in weight and cost.

  In addition, the water intake / discharge part is constituted by a water pump made up of an impeller 4, and the oil intake / discharge part is made up of an internal gear pump made up of an inner rotor 6 and an outer rotor 7. Therefore, the electric pump 1 that has a relatively simple structure, is unlikely to fail, and can be easily maintained can be provided.

  Further, when the electric pump 1 is operated, the maximum timing of the torque ripple periodically generated by the magnetic action of the magnet 51 and each coil 52 is periodically applied to the shaft 3 by the rotational operation of the impeller 4 and the inner rotor 6. This coincides with the maximum timing of the combined torque of the generated drive torques. Therefore, the shaft 3 can be rotated with the minimum required torque, and the motor 5 can be downsized to reliably achieve the weight reduction and cost reduction of the electric pump 1.

  In the embodiment of the present invention, the number of blades 4a of the impeller 4 is six and the number of external teeth 6a of the inner rotor 6 is six. However, if the number of blades 4a and the number of external teeth 6a is the same, Other numbers may be used.

  In the embodiment of the present invention, the number of coils 52 of the motor 5 is three and the number of magnetic poles of the magnet 51 is two. However, the number of magnetic poles of the magnet 51 and the number of coils 52 are not limited thereto. That is, the number of occurrences of torque ripple per rotation of the motor 5 is an integral multiple of the number of pressure fluctuations in the water pump chamber 2a and the oil pump chamber 2c per rotation of the impeller 4 and the inner rotor 6. That's fine.

  Further, in the embodiment of the present invention, the timing at which the maximum value of pressure fluctuation in the water pump chamber 2a and the timing at which the maximum value of pressure fluctuation in the oil pump chamber 2c are reached are set to be shifted from each other by a half cycle. However, the present invention is not limited to this, and it is only necessary that the maximum values of the periodic pressure fluctuations generated in the water pump chamber 2a and the oil pump chamber 2c are shifted from each other.

  In the embodiment of the present invention, the magnet 51 is a rotor and the three coils 52 are stators. However, the three coils 52 are fixed around the shaft 3 to be a rotor, and the magnets 51 are three coils 52. The stator may be fixed around.

  In the embodiment of the present invention, the oil pump is constituted by the inner rotor 6 and the outer rotor 7, but the number of pressure fluctuations in the water pump chamber 2a and the oil pump chamber 2c per one rotation of the shaft 3 is the same. If possible, other oil pumps may be used. For example, a structure of an external gear pump, a vane pump, and a swash plate pump may be used.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a vehicular electric pump including both a water pump that supplies water and an oil pump that supplies oil.

DESCRIPTION OF SYMBOLS 1 Electric pump 2 Housing 2a Water pump chamber 2b Motor chamber 2c Oil pump chamber 3 Shaft 4 Impeller (1st rotary body)
4a Blade 5 Motor 6 Inner rotor (second rotating body)
6a External teeth 7 Outer rotor 50 Stator 51 Magnet (rotor)
52 coils

Claims (3)

A housing in which a water pump chamber, an oil pump chamber and a motor chamber are formed in series;
A shaft rotatably supported inside the housing and into which the water pump chamber, the oil pump chamber, and the motor chamber are inserted;
A motor housed in the motor chamber and rotating the shaft;
A first rotating body fixed integrally with the shaft and housed in the water pump chamber, and periodically sucking and discharging water by a rotating operation;
A second rotating body fixed integrally with the shaft and housed in the oil pump chamber and periodically sucking and discharging oil by a rotating operation;
In the water pump chamber and the oil pump chamber, the maximum values of the periodic pressure fluctuations respectively generated by the suction and discharge of water and oil due to the rotating operation of the first and second rotating bodies are set so as to deviate from each other. An electric pump characterized by that. The electric pump according to claim 1,
The first rotating body is an impeller in which a plurality of blades are provided at equal intervals around the shaft,
The second rotating body is a spur gear-shaped inner rotor having a plurality of external teeth formed on the outer periphery,
The oil pump chamber accommodates an outer rotor having a plurality of inner teeth formed on the inner periphery thereof that mesh with the outer teeth with the inner rotor and the rotational axis shifted.
The blades and the external teeth are set to the same number so that the number of pressure fluctuations per rotation of the impeller and the inner rotor is the same. The oil pump chamber has a timing at which the maximum pressure fluctuation of the water pump chamber immediately after passing through the water discharge portion in the pump chamber and the opening area of the oil suction and discharge portion in the oil pump chamber are minimized. An electric pump characterized in that it is set so that the timing at which the maximum value of the pressure fluctuation is shifted from each other. The electric pump according to claim 1 or 2,
The motor fixes one of a plurality of magnets having a plurality of coils and a plurality of magnetic poles around the shaft as a rotor, and the other is arranged around the rotor as a stator. Is configured to rotate the shaft,
The least common multiple of the number of coils and the number of magnetic poles of the magnet is an integral multiple of the number of pressure fluctuations per rotation of the first and second rotating bodies,
The positions of the coils and the magnetic poles around the shaft are the timing at which the maximum torque ripple generated periodically by the least common multiple due to the magnetic action of the coils and the magnet is the pressure fluctuation in the water pump chamber and An electric pump characterized by being set to coincide with a timing of a maximum value periodically generated in a combined value of pressure fluctuations in the oil pump chamber.

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