JP2008263753A - Cooling device for vehicular rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently cool a stator core and a coil end according to the generation rate of iron loss and copper loss. <P>SOLUTION: At the upper part of the inside of a housing, there are provided a pipe A for supplying a large quantity of cooling oil by the stator core and a pipe B for supplying a large quantity of cooling oil by the coil end. A selector controlled by an ECU switches the cooling oil supply from a cooling oil pump to the pipes A, B. The ECU executes a program including: a step (S1010) for detecting the number N of rotation of a motor; a step (S1020) for calculating motor torque; a step (S1060) for supplying the cooling oil to the pipe A when the operating point of the motor belongs to an area (2) where the iron loss accounts for a large percentage of loss ((2) in S1040); and a step (S1070) for supplying the cooling oil with the pipe B when the operating point of the motor belongs to an area (3) where the copper loss accounts for a large percentage of loss ((3) in S1040). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooling device for a rotating electrical machine (such as a motor, a generator, and a motor generator) mounted on a vehicle, and in particular, a liquid refrigerant that accurately cools copper loss and iron loss that change according to the driving state of the vehicle. It relates to the cooling device used.

  A motor or a generator mounted on a vehicle such as an automobile includes a rotor (rotor) and a stator core that is disposed around the rotor and has a stator winding wound thereon. The motor energizes the stator windings to obtain rotational force, and the generator extracts the current flowing through the stator windings by the rotation of the rotor. When a current flows through the stator winding during the rotation of the rotor, the stator core and the stator winding generate heat. If the temperature of the stator core and the coil end is excessively increased by leaving such heat generation, problems such as dielectric breakdown between the stator and the core, stator coil burnout, and permanent magnet thermal demagnetization may occur. is there.

  By the way, when the torque T of the motor is larger, the copper loss increases. Since the coil end generally has a smaller heat capacity than the stator core, the temperature rise rate of the winding is faster than that of the stator core, and it is more effective to increase the cooling capacity of the coil end (winding) mainly. It is. On the other hand, when the rotational speed N of the motor is larger, the iron loss increases and the temperature of the stator core portion increases, so it is more effective to mainly increase the cooling capacity of the stator core portion.

  Japanese Patent Application Laid-Open No. 2006-074962 (Patent Document 1) discloses a cooling device for an electric motor that efficiently cools the electric motor in consideration of these. The motor cooling device includes a first circulation unit that circulates a first cooling fluid that cools a stator core included in the motor, and a second circulation that circulates a second cooling fluid that cools a winding wound around the stator core. And a flow rate controller for controlling the flow rate of the first cooling fluid by the first circulation unit and the flow rate of the second cooling fluid by the second circulation unit.

According to this motor cooling device, it is possible to provide a motor cooling device that efficiently cools the motor with low power consumption. That is, more specifically, the first cooling fluid circulates in the core cooling flow path by the electric core pump, thereby cooling the stator core and the winding from the stator side. The cooling capacity of the stator core by the first cooling fluid is determined by the flow rate of the first cooling fluid in the core cooling flow path. The flow rate of the first cooling fluid is determined by the rotational speed of the core pump. Similarly, the second cooling fluid circulates in the winding cooling flow path by an electric winding pump, thereby cooling the winding from the coil end side. The cooling capacity of the winding by the second cooling fluid is determined by the flow rate of the second cooling fluid in the winding cooling flow path. The flow rate of the second cooling fluid is determined by the number of rotations of the winding pump.
JP 2006-074962 A

  However, in Patent Document 1 described above, the rotational speed of the winding pump must be controlled while controlling the rotational speed of the core pump according to the degree of occurrence of iron loss and copper loss. For this reason, two pumps are required and the control is complicated. Furthermore, the cooling channel requires a core cooling channel and a winding cooling channel, which may increase the size of the electric motor.

  The present invention has been made to solve the above-described problems, and its purpose is to provide a stator core and a stator coil end that are more required to be cooled depending on the degree of occurrence of iron loss and copper loss. It is an object of the present invention to provide a vehicular rotating electrical machine cooling device capable of supplying a large amount of liquid refrigerant with a simple configuration.

  According to a first aspect of the present invention, there is provided a cooling apparatus for a rotating electrical machine for a vehicle in which a plurality of slots and teeth are alternately formed, a hollow cylindrical stator core having a coil mounted in the slot, and an inner peripheral side of the hollow portion of the stator core. A rotating electrical machine for a vehicle constituted by a rotatable rotor arranged is cooled. An insulator is attached to the slot, and a stator coil is wound thereon, and a stator coil end is formed outside the stator core in the rotation axis direction. This cooling device is provided above the stator core and the stator coil end, and is provided in a direction parallel to the rotating shaft to supply the stator core with a cooling oil amount larger than the cooling oil amount supplied to the stator coil end. A first supply pipe having a cooling oil jet opening that opens downward, and a cooling oil amount provided in parallel to the first supply pipe, which is larger than the cooling oil amount supplied to the stator core. To switch the connection of the piping so that the cooling oil is supplied to either the first supply piping or the second supply piping, and the second supply piping having a cooling oil jet opening that opens downward for supply. Switching means, one pump for supplying cooling oil in communication with either the first supply pipe or the second supply pipe via the switching means, and the rotational speed and torque of the rotating electrical machine. Based on, and a control means for controlling the switching means.

  According to the first invention, a rotating electrical machine (motor, motor generator, etc.) mounted for vehicle travel may be used in a high rotational speed region or a high torque region depending on the travel of the vehicle. In the high rotation region, the iron loss increases and the stator core needs to be cooled. In the high torque region, the copper loss increases and the stator coil end needs to be cooled. The cooling oil discharged from one pump is supplied to either the first supply pipe or the second supply pipe by the switching valve. Here, since there is much iron loss when the rotation speed of a rotary electric machine is high, in order to cool a stator core, cooling oil is supplied to 1st supply piping, and a stator core is cooled more. On the other hand, if the torque of the rotating electrical machine is high, there is a large amount of copper loss, so that cooling oil is supplied to the second supply pipe to cool the stator coil end in order to cool the stator coil end. Thus, the cooling oil supplied from one pump is distributed by the switching means according to the rate of thermal loss. Thereby, the rotary electric machine mounted for vehicle travel can be cooled more efficiently and with a simple configuration. As a result, the stator core and the stator coil end can be supplied with more liquid refrigerant in a simple configuration depending on the degree of occurrence of iron loss and copper loss. A cooling device can be provided.

  In the cooling apparatus for a rotating electrical machine for a vehicle according to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the control means may cause the iron loss to occur based on the rotational speed and torque of the rotating electrical machine. And means for controlling the switching means to supply the cooling oil to the first supply pipe.

  According to the second invention, since the iron loss is large when the rotational speed of the rotating electrical machine is high, the cooling oil is supplied to the first supply pipe to cool the stator core from the stator coil end in order to cool the stator core.

  In the vehicular rotating electrical machine cooling apparatus according to the third aspect of the invention, in addition to the configuration of the first aspect of the invention, the control means is configured to generate a copper loss based on the rotational speed and torque of the rotating electric machine. And means for controlling the switching means to supply the cooling oil to the second supply pipe.

  According to the third invention, since the copper loss is large when the torque of the rotating electrical machine is high, the cooling oil is supplied to the second supply pipe to cool the stator coil end from the stator core in order to cool the stator coil end. .

  In the cooling device for a rotating electrical machine for a vehicle according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the first supply pipe corresponds to the stator coil end at a position corresponding to the stator core. A cooling oil jet outlet or a larger number of cooling oil jet outlets than the position, and the second supply pipe has a larger cooling oil jet outlet or a position at a position corresponding to the stator coil end than at a position corresponding to the stator core. More cooling oil outlets are provided.

  According to the fourth aspect of the present invention, the first supply pipe has a large cooling oil jet outlet or more at a position corresponding to the stator core facing downward (the first supply pipe is provided above the stator core). Since there are many cooling oil jet nozzles, the stator core can be cooled more than the stator coil end with a simple configuration. In addition, the second supply pipe has a large cooling oil outlet or more at a position corresponding to the stator coil end facing downward (the second supply pipe is provided above the stator coil end). Therefore, the stator coil end can be cooled more than the stator core with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  In the following description, the rotating electric machine according to the present invention is described as an electric motor (hereinafter sometimes referred to as a motor), but the present invention is not limited to the electric motor. For example, it may be applied to a rotating electrical machine such as a motor generator, a generator, or an alternator.

  With reference to FIG. 1, an electric motor mounted on a vehicle to which a cooling device according to an embodiment of the present invention is applied will be described. As shown in FIG. 1, the vehicle is mounted with the rotating shaft horizontal or substantially horizontal.

  FIG. 1 shows a cross-sectional view of such an electric motor. This electric motor includes a rotor part including a rotor 1010 rotatably supported by two bearings 1020 and a stator part including a stator core 2000 installed in the outer peripheral direction of the rotor 1010. The rotor 1010 is supported by a bearing 1020, rotates about the rotation shaft 1000, and transmits rotational torque to the power train of the vehicle.

  A stator core 2000 is provided at a position corresponding to the rotor 1010 via a slight gap. A coil is wound around the stator core 2000 in a slit provided so as to penetrate the stator core 2000 in a direction parallel to the rotation axis. When a current is passed through the coil, the stator core 2000 generates a magnetic field for rotating the rotor 1010.

  An end portion of the stator coil wound around the stator core 2000 is formed as a stator coil end 2010. As shown in FIG. 2, the stator coil is provided with insulating paper 2012 in slots 2110 of the stator core 2000. A tooth 2120 is formed between the slots 2110. As shown in FIG. 2, the insulating paper 2012 is provided so as to protrude from the slot 2110. Therefore, the insulating paper 2012 is covered at the root of the stator coil end 2010.

  Note that the numbers and shapes of the slots 2110 and the teeth 2120 in the rotor 1010 shown in FIG. 2 are merely examples, and the present invention is not limited to such numbers and shapes. Further, the rotor 1010 may be configured by laminating a large number of electromagnetic steel plates (thin plates of about 0.3 mm to 0.5 mm), or may be integrated.

  Note that the rotating shaft 1000, the rotor 1010, the bearing 1020, the stator core 2000, and the stator coil end 2010, which are these components, are housed in the housing 3000.

  With reference to FIG. 3, the structure of the cooling device according to the present embodiment will be described. FIG. 3 is a view of the cooling device as viewed from the direction of the rotation axis 1000.

  Two pipes A 3030 and a pipe 3050 for supplying cooling oil to the stator coil end 2010 and the stator core 2000 are disposed above the stator coil end 2010 and the stator core 2000. As will be described in detail later, the pipe A3030 is a pipe for cooling the heat generated due to the iron loss, and the amount of the cooling oil supplied to the stator coil end 2010 is small, and the cooling oil supplied to the stator core 2000 Large amount. Pipe B3050 is a pipe for cooling the heat generated due to copper loss, and the amount of cooling oil supplied to stator coil end 2010 is large, and the amount of cooling oil supplied to stator core 2000 is small.

  These pipes A3030 are connected to a switching valve 3010 via a connecting pipe 3020, a pipe B3050 is connected to a switching valve 3010, and the switching valve 310 is connected to an oil pump (not shown) via a supply pipe 3005. One oil pump is sufficient.

  The switching valve 3010 switches between a state in which the connection pipe 3020 on the pipe A 3030 side and the supply pipe 3005 are connected and a state in which the connection pipe 3040 on the pipe B 3050 side and the supply pipe 3005 are connected. Furthermore, the switching valve 3010 is in a state in which the connection piping 3020 on the pipe A 3030 side and the connection piping 3040 on the pipe B 3050 side and the supply piping 3005 are connected, or in a state in which the connection piping 3020, the connection piping 3040 and the supply piping 3005 are not connected. It may be realized. The switching valve 3010 is controlled by an ECU (Electronic Control Unit) described later.

  The configuration of the pipe A3030 will be described with reference to FIG. The pipe A 3030 has a large jet nozzle at a position corresponding to the stator core 2000 and a small jet nozzle at a position corresponding to the stator coil end 2010. It should be noted that there may be many jet nozzles instead of large jet nozzles, and there may be few jet nozzles instead of small jet nozzles. Further, it is also preferable that the cooling oil flows through the pipe A3030 not only from the right direction to the left direction but also from the left direction to the right direction.

  In the pipe A3030 having such a configuration, the stator core 2000 that generates a large amount of iron loss and has high heat can be sufficiently cooled in the operation region of the motor in which the generation ratio of iron loss is large among the losses. On the other hand, the stator coil end 2010 in which a small copper loss has occurred can also be cooled.

  The configuration of the pipe B3050 will be described with reference to FIG. The pipe B3050 has a small jet nozzle at a position corresponding to the stator core 2000, and has a large jet nozzle at a position corresponding to the stator coil end 2010. It should be noted that there may be many jet nozzles instead of large jet nozzles, and there may be few jet nozzles instead of small jet nozzles. Furthermore, it is also preferable that the cooling oil flows through the pipe B3050 not only from the right direction to the left direction but also from the left direction to the right direction.

  In the pipe B3050 having such a configuration, the stator coil end 2010 that generates a large amount of copper loss and becomes high heat can be sufficiently cooled in an operation region of a motor in which the loss occurrence ratio is large. On the other hand, the stator core 2000 in which a small iron loss occurs can be cooled.

  FIG. 6 shows a map for determining the operating state of the motor. This map is a map in which the horizontal axis represents motor rotation speed and the vertical axis represents motor torque. The curve shows the maximum output curve of the motor.

  The operation state of the motor can be classified into three regions shown in FIG. Assuming that the rated torque of the motor is Tq (1), the maximum torque is TqMAX, the reference rotational speed is N (1), and the maximum rotational speed is Nmax, in FIG. 6, the rated torque Tq (1) or less and the reference rotational speed Region (1) below N (1) is the normal operating state. Further, the region (2) that is equal to or less than the rated torque Tq (1) and equal to or greater than the reference rotational speed N (1) is an operation state that is performed in a short time. Further, the region (3) not less than the rated torque Tq (1) and not more than the reference rotational speed N (1) is a maximum torque output region, which is an operation state performed in a short time.

  Generally, as the motor rotation speed N increases, the motor iron loss increases and the amount of heat generated in the laminated steel plate portion of the stator core 2010 increases. On the other hand, as the motor torque T increases, the copper loss of the motor increases and the amount of heat generated at the stator coil end portion increases.

  In the cooling device according to the present embodiment, when it is determined that the operating point of the motor is included in the region (2) in which the rotational speed N of the motor is larger and the iron loss is larger, the pipe A3030 is mainly used. The stator core 2000 is cooled. In addition, since there is a possibility that the heat of the stator core 2000 wraps around the stator coil end 2010 and the copper loss is not zero, the stator coil end 2010 may also become high temperature. Cooling.

  On the other hand, when it is determined that the operating point of the motor is included in the region (3) where the motor torque T is larger and the copper loss is larger, the stator coil end 2010 is mainly cooled using the pipe B3050. . Note that there is a possibility that the heat of the stator coil end 2010 wraps around the stator core 2000, and the iron core is not zero, so that the stator core 2000 may also become high temperature. Therefore, the stator core 2000 is also cooled by the pipe B3050.

  Note that the map shown in FIG. 6 is an example, and the present invention is not limited to the map shown in FIG.

  The cooling device according to the present embodiment uses the map shown in FIG. 6 to detect or calculate the motor rotation speed N and the motor torque T for each predetermined cycle time, and on the map of FIG. Determine the operating range of the motor. The cooling device determines whether to cool with pipe A3030 or pipe B3050 according to this operating region.

  The cooling device according to the present embodiment includes a CPU (Central Processing Unit) included in the ECU, a memory, and a program that is read from the memory and executed by the CPU even in hardware mainly composed of digital circuits and analog circuits. It can also be realized with software based on the above. In general, it is said that it is advantageous in terms of operation speed when realized by hardware, and advantageous in terms of design change when realized by software. In the following, a case where a cooling device is realized as software will be described.

  With reference to FIG. 7, the control structure of the program executed by the ECU in order to realize the cooling device according to the present embodiment will be described. This program is a subroutine and is repeatedly executed at a predetermined cycle time.

  In step (hereinafter, step is abbreviated as S) 1000, the ECU determines whether or not to start motor cooling. For example, it may be determined that the motor cooling is started when the motor is started, or the motor cooling is determined to be started when a predetermined time has elapsed after the motor is started. If it is determined that motor cooling is to be started (YES in S1000), the process proceeds to S1010. Otherwise (NO in S1000), this subroutine process ends.

  In S1010, the ECU detects the motor rotation speed N. In S1020, the ECU calculates motor torque T.

  In S1030, the ECU determines which of the three regions in FIG. 6 includes the operating point of the motor based on the detected motor rotation speed N and the calculated motor torque T.

  In S1040, the ECU determines whether the operating point of the motor belongs to region (1), region (2), or region (3) in FIG. If it is determined that the operating point of the motor belongs to region (1) in FIG. 6 ((1) in S1040), the process proceeds to S1050. If it is determined that the operating point of the motor belongs to region (2) in FIG. 6 ((2) in S1040), the process proceeds to S1060. If it is determined that the operating point of the motor belongs to region (3) in FIG. 6 ((3) in S1040), the process proceeds to S1070.

  In S1050, ECU controls switching valve 3010 to supply cooling oil to pipe A3030 and / or pipe B. Here, when it is not necessary to cool the motor (for example, determined based on a temperature signal from a thermistor provided in the motor), a switching valve is provided so that the cooling oil is not supplied to the pipe A3030 and the pipe B. It is also possible to control 3010 to stop the operation of the oil pump to avoid wasting energy.

  In S1060, ECU controls switching valve 3010 to supply cooling oil to pipe A3030. The oil pump is operating. Thereafter, the process proceeds to S1080.

  In S1070, ECU controls switching valve 3010 to supply cooling oil to pipe B3050. The oil pump is operating. Thereafter, the process proceeds to S1080.

  In S1080, the ECU determines whether or not to end the motor cooling. For example, when the operation of the motor is finished, it is determined that the motor cooling is finished. If it is determined that the motor cooling is to be terminated (YES in S1080), this subroutine processing is terminated. Otherwise (NO at S1080), the process returns to S1010.

  The operation of the cooling device according to the present embodiment based on the above-described structure and flowchart will be described.

  When an operation command signal is output to the motor, motor cooling is started (YES in S1000). The motor rotational speed N is detected (S1010), the motor torque T is detected (S1020), and the operating point of the motor is determined using the motor rotational speed N and the motor torque T as parameters (S1030).

  In the map having the motor rotation speed N and the motor torque T as parameters as shown in FIG. 6, whether the motor operating point belongs to the region (1), the region (2), or the region (3). Determination is made (S1040).

  When it is determined that the operating point of the motor is included in the region (2) in which the rotational speed N of the motor is larger and the iron loss is larger ((2) in S1040), the switching valve 3010 is connected to the pipe A3030 side. With the pipe 3020 and the supply pipe 3005 connected, the cooling oil is supplied to the pipe A3030. At this time, since the pipe A3030 is used and cooled, the stator core 2000 is mainly cooled. Further, at this time, since the heat of the stator core 2000 may wrap around the stator coil end 2010 and the copper loss is not zero, the stator coil end 2010 is also cooled by the pipe A3030.

  If it is determined that the operating point of the motor is included in the region (3) where the motor torque T is larger and the copper loss is larger ((3) in S1040), the switching valve 3010 is connected to the pipe B3050 side. The cooling oil is supplied to the pipe B3050 with the connection of the 3040 and the supply pipe 3005. At this time, since the pipe B3050 is used and cooled, the stator coil end 2010 is mainly cooled. Note that the stator core 2000 is also cooled by the pipe B3050 because the heat of the stator coil end 2010 may wrap around the stator core 2000 and the iron loss is not zero.

  As described above, according to the cooling device according to the present embodiment, an appropriate amount of cooling oil corresponding to the ratio of the iron loss and copper loss of the motor can be supplied to the stator core and the stator coil end, respectively. Thus, it can be efficiently cooled.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing of the electric motor to which the cooling device which concerns on embodiment of this invention is applied. It is an enlarged view of a stator part. It is the figure which looked at the cooling device which concerns on embodiment of this invention from the rotating shaft direction. It is the figure which looked at the pipe A of FIG. 3 from the electric motor side surface on the rotating shaft. It is the figure which looked at the pipe B of FIG. 3 from the motor side surface on the rotating shaft. It is a figure which shows the operation area | region of the electric motor to which the cooling device which concerns on embodiment of this invention is applied. It is a flowchart which shows the control structure of the program performed with the cooling device which concerns on embodiment of this invention.

Explanation of symbols

  1000 rotating shaft, 1010 rotor, 1020 bearing, 2000 stator core, 2010 stator coil end, 2012 insulating paper, 2110 slot, 2120 teeth, 3000 housing, 3010 switching valve, 3030 pipe A, 3050 pipe B.

Claims (4)

A vehicle comprising a hollow cylindrical stator core in which a plurality of slots and teeth are alternately formed, and a coil is mounted in the slot, and a rotatable rotor disposed on the inner peripheral side of the hollow portion of the stator core A cooling device for a rotary electric machine for an electric machine, wherein an insulator is mounted on the slot and a stator coil is wound, and a stator coil end is formed on the outer side in the rotation axis direction from the stator core,
In order to supply the stator core with a cooling oil amount which is provided above the stator core and the stator coil end and is provided in a direction parallel to the rotation axis, which is larger than the cooling oil amount supplied to the stator coil end. A first supply pipe having a cooling oil outlet opening downward;
In order to supply a cooling oil amount, which is provided in parallel with the first supply pipe, to the stator coil end, a cooling oil amount larger than the cooling oil amount supplied to the stator core is provided. A second supply line;
Switching means for switching the connection of the pipe so as to supply the cooling oil to either the first supply pipe or the second supply pipe;
One pump for supplying the cooling oil in communication with either the first supply pipe or the second supply pipe via the switching means;
A cooling device for a vehicular rotating electrical machine, comprising: control means for controlling the switching means based on the rotational speed and torque of the rotating electrical machine.   The control means is means for controlling the switching means to supply cooling oil to the first supply pipe when the occurrence of iron loss is large based on the rotational speed and torque of the rotating electrical machine. The vehicular rotating electrical machine cooling device according to claim 1, comprising:   The control means is means for controlling the switching means so as to supply cooling oil to the second supply pipe when copper loss is frequently generated based on the rotational speed and torque of the rotating electrical machine. The vehicular rotating electrical machine cooling device according to claim 1, comprising: The first supply pipe includes a larger cooling oil outlet or more cooling oil outlets at a position corresponding to the stator core than at a position corresponding to the stator coil end.
The said 2nd supply piping is provided with a larger cooling oil jet nozzle or more cooling oil jet nozzles in the position corresponding to the said stator coil end than the position corresponding to the said stator core. A cooling apparatus for a vehicular rotating electrical machine according to claim 1.

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