JP2006161836A - Hydraulic feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic feeder which is formed to determine the voltage value applied to a low voltage battery from a converter corresponding to the oil temperature of a hydraulic oil. <P>SOLUTION: The hydraulic feeder is comprised of an engine 2 and a motor generator 4 which are connected in series. The oil pressure feeder comprises the battery 10 to give and receive electric power between the motor generator 4, a mechanical oil pump 20 driven by a driving source, an electric motor 22 driven by a 12V battery 24, a motor oil pump 21 driven by the electric motor 22, an automatic transmission mechanism 7 to change gear and transmit rotational drive force of the driving source to a wheel 8 by setting the change gear ratio using the hydraulic oil supplied from the mechanical oil pump 20 and the motor oil pump 21, an oil temperature sensor 42 to detect the oil temperature of the hydraulic oil, and a DC-DC converter 14 to transform the voltage of the battery 10 and charge the battery 24, and the electric motor 22 is actuated by giving a drive torque to be output to the electric motor 22 as a torque command value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic pressure supply device that is used in a hybrid vehicle or the like and supplies hydraulic oil to a transmission mechanism or the like by an electric oil pump when the engine is stopped.

  In order to improve environmental efficiency by improving fuel consumption and reducing exhaust gas, hybrid vehicles that can be driven by a drive source that combines an engine and a motor that can generate electric power (motor generator) have been developed. This hybrid vehicle performs so-called idle stop control in which the engine is stopped when the vehicle is stopped. However, when the engine stops, the mechanical oil pump that supplies hydraulic oil to the transmission mechanism and the like is also stopped by the engine. An electric oil pump that is driven by an electric motor driven by a battery and supplies hydraulic oil only when the operation is performed is provided.

  At this time, since the hydraulic pressure of the hydraulic oil discharged from the electric oil pump depends on the viscosity of the hydraulic oil, control in consideration of the oil temperature of the hydraulic oil is necessary. For example, when the hydraulic oil pressure discharged from the electric oil pump is configured to be controlled by the voltage value applied to the electric motor that drives the electric oil pump, the oil temperature of the hydraulic oil is detected, There is known a drive control device (pump driver) for an electric oil pump configured to change a voltage applied to an electric motor in accordance with a detected oil temperature (see, for example, Patent Document 1). In this case, the pump driver controls the applied voltage by controlling the duty ratio of the voltage applied to the electric motor in accordance with the oil temperature of the hydraulic oil.

JP 2002-206630 A

  However, the hydraulic pressure of hydraulic oil discharged from the electric oil pump is controlled based on the pump driving torque output from the electric motor in addition to the voltage applied to the electric motor. In this case, the pump The driver controls the winding current value of the electric motor proportional to the pump driving torque. Therefore, in such a system, control for changing the voltage applied to the electric motor by the pump driver is not performed.

  The present invention has been made in view of such problems, and a low voltage battery, which is a drive source of an electric motor that drives an electric oil pump, is charged via a converter from a high voltage battery that exchanges power with a motor generator. An object of the present invention is to provide a hydraulic pressure supply device configured to determine a voltage value applied from a converter to a low-voltage battery in accordance with the oil temperature of hydraulic oil in the hybrid vehicle configured as described above.

  In order to solve the above-described problem, a hydraulic pressure supply device according to the present invention includes an engine and a motor generator connected in series, and includes a drive source for driving a vehicle (for example, the hybrid vehicle 1 in the embodiment), and a motor generator. An electric motor driven by a high-voltage battery (for example, the battery 10 in the embodiment) that exchanges power between them, a mechanical oil pump that is driven by a drive source, and a low-voltage battery (for example, the 12V battery 24 in the embodiment) And an electric oil pump driven by the electric motor, a mechanical oil pump and hydraulic oil supplied from the electric oil pump, and a transmission gear ratio is set, and the rotational driving force of the drive source is changed and transmitted to the wheels. Transmission mechanism (for example, automatic transmission mechanism 7 in the embodiment) and oil for detecting the oil temperature of the hydraulic oil The electric motor is commanded to the electric motor as a torque command value with a sensor, a converter for transforming the voltage of the high voltage battery to charge the low voltage battery (for example, the DC-DC converter 14 in the embodiment), and a pump drive torque to be output. A control unit that operates the motor and controls the output voltage applied to the low-voltage battery of the converter. The control unit controls the output voltage according to the oil temperature detected by the oil temperature sensor. Configured to do.

  In such a hydraulic pressure supply device according to the present invention, when the control unit is operating the electric motor, it is preferable to control the converter so that the output voltage is maintained at a high voltage, and the oil temperature sensor It is preferable that the control unit controls the converter so that the output voltage is maintained at a high voltage when the oil temperature detected by the above is equal to or higher than a predetermined value.

Alternatively, in the hydraulic pressure supply device according to the present invention, the control unit is configured to control the output voltage according to the amount of electric power used by the electric load connected to the low-voltage battery, and the electric motor is operating. In some cases, it is preferable to control the converter so that it does not fall below the minimum value of the output voltage determined according to the oil temperature detected by the oil temperature sensor (for example, the minimum sustain voltage V _L in the embodiment).

  In the hydraulic pressure supply device according to the present invention configured as described above, the control unit is configured to continue the current control on the converter until the electric motor stops when the oil temperature sensor fails. It is preferred that

  In the hydraulic pressure supply apparatus according to the present invention, the electric motor is preferably a three-phase brushless sensorless motor.

  When the hydraulic pressure supply device according to the present invention is configured as described above, it is possible to suppress the harness current upstream of the electric motor by increasing the output voltage of the converter, and the oil temperature of the hydraulic oil rises to increase the electric motor Sufficient power can be supplied when power consumption increases.

  Note that when the oil temperature sensor fails, the control unit can be operated without stopping the electric oil pump by configuring the control unit to continue the current control on the converter until the electric motor stops. .

  In addition, such a hydraulic pressure supply device according to the present invention can save energy and can be manufactured at low cost by configuring the electric motor with a three-phase brushless sensorless motor.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, the configuration of a traveling drive system of a hybrid vehicle having a hydraulic pressure supply device according to the present invention will be described with reference to FIG.

  The hybrid vehicle 1 has an engine 2 and a motor (hereinafter referred to as “motor generator”) 4 that are connected in series as a drive source, and a lockup clutch 5 that is connected to the drive source. A torque converter 6 and an automatic transmission mechanism 7 are disposed, and an output shaft of the automatic transmission mechanism 7 is connected to the wheels 8. For this reason, the driving force from the engine 2 and the motor generator 4 is alternatively or jointly transmitted through the torque converter 6 with the lockup clutch 5 and the automatic transmission mechanism 7 and transmitted to the wheels 8, so that the hybrid vehicle 1 Is driven to travel.

  Further, when the accelerator pedal 9 is released during traveling and the vehicle decelerates (coasting), the driving force from the wheels 8 is driven via the automatic transmission mechanism 7 and the torque converter 6 with the lock-up clutch 5. At this time, an engine braking action (braking action based on engine friction torque) is generated by the engine 2 and the motor generator 4 is driven to generate electric power (energy regeneration).

  The engine 2 is a multi-cylinder reciprocating type engine that can perform fuel injection control and injection fuel ignition control for each cylinder, and can perform valve operation control that closes the intake and exhaust valves of each cylinder to make the cylinders rest. An operation control device 3 is provided. The operation of the engine operation control device 3 is controlled by a control unit (ECU) 15 to be described later, and automatic stop / start control (so-called idle stop control) of the engine 2 is performed under predetermined operation conditions. The cylinder resting control is performed to close the intake / exhaust valves of some or all cylinders.

  The torque converter 6 can be engaged and disengaged between its input / output members (pump member and turbine member) by the lock-up clutch 5. When the lock-up clutch 5 is released, the drive source (the engine 2 and the motor generator 4). ) And the automatic transmission mechanism 7, the rotational driving force is transmitted via the torque converter 6. On the other hand, when the lockup clutch 5 is engaged, the drive source (the output shaft of the motor generator 4) and the input shaft of the automatic transmission mechanism 7 are directly connected by bypassing the torque converter 6. Engagement / disengagement control of the lockup clutch 5 is performed by a hydraulic control valve (HCV) 12, and the hydraulic control valve 12 is controlled by a control unit 15. That is, the control unit 15 performs engagement / disengagement control of the lockup clutch 5.

  The automatic transmission mechanism 7 is a stepped transmission mechanism composed of a plurality of transmission gear trains, and automatically supplies a hydraulic pressure from the hydraulic control valve 12 to the hydraulically operated transmission clutch to automatically set a desired gear stage according to the operating state. To perform automatic shifting. At this time, the hydraulic control valve 12 is controlled by the control unit 15. That is, automatic shift control according to the driving state is performed by the control unit 15.

  The motor generator 4 is driven by receiving electric power supplied from the battery 10 via the power drive unit (PDU) 11. At this time, the power drive unit 11 is controlled by the control unit 15. That is, drive control of the motor generator 4 is performed by the control unit 15. Further, when the hybrid vehicle 1 travels at a reduced speed, the motor generator 4 is driven to rotate by receiving the driving force from the wheels 8, which functions as a generator to generate a regenerative braking force, and the kinetic energy of the vehicle body is used as electric energy. The battery 10 is collected and charged via the power drive unit 11. The regenerative energy control at this time is also performed by the control unit 15 via the power drive unit 11.

  In the hybrid vehicle 1, the hydraulic pressure supply source (hydraulic pressure supply device 30) of the lock-up clutch 5 and the automatic transmission mechanism 7 includes a mechanical oil pump 20 and an electric oil pump 21. The mechanical oil pump 20 is connected to a driving source (the engine 2 and the motor generator 4), and is operated by the driving force of the driving source. In FIG. 1, the mechanical oil pump 20 is shown beside the engine 2 for the sake of simplicity, but actually, the mechanical oil pump 20 includes the torque converter 6 and the automatic transmission mechanism. 7.

  On the other hand, the electric oil pump 21 is driven by an electric motor 22. The electric motor 22 is driven by controlling the electric power supplied from the 12V battery 24 by the pump driver 23, and the pump driver 23 is controlled by the control unit 15. As described above, when the engine 2 is stopped due to the idle stop control performed by the control unit 15, the hydraulic pressure is not supplied from the mechanical oil pump 20. The motor 22 is driven and hydraulic oil is supplied from the electric oil pump 21. The electric motor 22 is a three-phase sensorless brushless motor that is more efficient than a DC brush motor, has a simpler structure, and is less expensive than a sensorless brushless motor.

  In the present embodiment, the 12V battery 24 is charged by the battery 10, but since the voltage of the battery 10 is as high as 144V, for example, the voltage of the battery 10 is transformed to a low voltage by the DC-DC converter 14. And used for charging. As shown in FIG. 2, the actual circuit configuration is such that the 12V battery 24 and the pump driver 23 are connected in parallel to the output terminal of the DC-DC converter 14. Is applied not only to the 12V battery 24 but also to the pump driver 23 and used to drive the electric motor 22 of the electric oil pump 21. At this time, the output voltage of the DC-DC converter 14 is controlled by the control unit 15. That is, the voltage applied to charge the 12V battery 24 and the voltage is controlled by the control unit 15.

  As described above, the control unit 15 controls the operation of the engine operation control device 3, the hydraulic control valve 12, the power drive unit 11, the pump driver 23, and the DC-DC converter 14. For the control, Various detection signals are input. For example, as shown in the figure, a detection signal from the accelerator sensor 17 that detects the depression of the accelerator pedal 9 and a detection signal from the rotation speed sensor 18 that detects the input / output rotation speed of the torque converter 6 are input. The control unit 15 includes a vehicle speed detection signal from the vehicle speed sensor, an engine speed detection signal from the engine rotation sensor, a shift position detection signal of the transmission, a brake operation detection signal from the brake sensor, a remaining capacity detection signal of the battery 10, and the like. Is input.

  Now, the above-described hydraulic pressure supply device 30 will be described in more detail with reference to FIG. The hydraulic pressure supply device 30 includes an oil pan 31, a strainer 32, a first oil passage 33 connected to the strainer 32 and the suction side of the mechanical oil pump 20, a discharge side of the mechanical oil pump 20, and a first hydraulic pressure control valve 12. A third oil passage 35 branched from the second oil passage 34 and the first oil passage 33 and connected to the suction side of the electric oil pump 21, and a fourth oil passage 36 connected to the discharge side of the electric oil pump 21 and the second oil passage 34. And a fifth oil passage 37 that connects the fourth oil passage 36 and the third oil passage 35 to each other. The fourth oil passage 36 is provided with a check valve 38 so that the hydraulic oil from the mechanical oil pump 20 does not flow back to the electric oil pump 21, and the fifth oil passage 37 has a fourth oil passage. An orifice 39 and a relief valve 40 are provided in this order from the path 36 side. The relief valve 40 is configured to be opened when the oil pressure in the fourth oil passage 36 reaches a predetermined value or more, and to allow the hydraulic oil in the fourth oil passage 36 to flow into the third oil passage 35. In the following description, a circuit in which the hydraulic oil discharged from the electric oil pump 21 returns to the oil pump 21 through the fifth oil passage 37 (orifice 39, relief valve 40) is referred to as a recirculation circuit.

  When the mechanical oil pump 20 is operated by the engine 2, the hydraulic oil in the oil pan 31 is sucked into the mechanical oil pump 20 from the strainer 32 through the first oil passage 33, and is added by the mechanical oil pump 20. And is discharged to the second oil passage 34 and supplied to the hydraulic control valve 12. On the other hand, when the engine 2 is stopped and hydraulic pressure cannot be supplied by the mechanical oil pump 20, the electric oil pump 21 is operated by the control unit 15, and the operating oil of the oil pan 31 is supplied from the strainer 32 to the first oil passage 33 and the first oil passage 33. The oil is sucked into the electric oil pump 21 through the three oil passages 35, pressurized by the electric oil pump 21, discharged to the fourth oil passage 36, and supplied from the second oil passage 34 to the hydraulic control valve 12.

  Therefore, even if the engine 2 is stopped by the idle stop control, the required oil pressure is supplied by the electric oil pump 21. Therefore, a delay in the rise of the oil pressure when the engine 2 is restarted is prevented, and a start response delay is prevented. Can do. The hydraulic fluid supplied to the lockup clutch 5 and the automatic transmission mechanism 7 via the hydraulic control valve 12 is returned to the oil pan 31 via the sixth oil passage 41.

  Here, since the electric motor 22 for operating the electric oil pump 21 is a brushless sensorless motor, the electric motor 22 includes a rotor having a permanent magnet and a stator coil provided so as to surround the rotor. The rotation is controlled by adjusting the pulse voltage applied from the driver 23 to the stator coil. The pulse voltage is controlled by a pulse width modulation (PWM) method for controlling the pulse width.

  By the way, such a brushless motor needs to control the pulse voltage applied to a stator coil according to the position of the permanent magnet of a rotor. Therefore, when the electric motor 22 is started, the pump driver 23 instantaneously cuts off the power supply, causes the electric motor 22 to free run, and operates the electric motor 22 as a synchronous generator with an internal permanent magnet. It has a positioning / synchronization mode that identifies the position of the rotor from the output voltage, and the electric motor 22 can be accurately operated by controlling the pulse voltage based on the result (this state is called a sensorless mode). .

  The electric oil pump 21 used in such a hybrid vehicle 1 is necessary for maintaining the function of the automatic transmission mechanism 7 while the engine 2 is stopped in idle stop control for the purpose of saving fuel. Electric power operation is required. In order to always secure the minimum hydraulic pressure required to maintain the function of the automatic transmission mechanism 7 while the engine 2 is stopped, the electric motor 22 is controlled with a pump driving torque that is not easily affected by the oil temperature and viscosity of the hydraulic oil. It is desirable to do. Therefore, the control unit 15 outputs the magnitude of the torque that the electric motor 22 should output to the pump driver 23 as a torque command value.

  There is a proportional relationship between the output torque (pump drive torque) of the electric motor 22 and the current value of the current flowing through the stator coil (referred to as “winding current”). The current value of the winding current is measured with respect to the torque command value from the current sensor 25, and control is performed so that the measured value becomes a predetermined value, that is, a predetermined torque (this control is referred to as “torque control” "). This is because if the control is performed using the voltage value applied to the electric motor 22, accurate control is more likely to be affected by changes in the applied original voltage and variations in the resistance value of the harness. .

In the hybrid vehicle 1 configured as described above, in the control unit 15, the electric motor 22 is driven and the electric oil pump 21 is operated before the vehicle speed becomes zero due to the stop of the engine 2 by the idle stop control. The relationship between the hydraulic pressure (line pressure P _L ) supplied to the hydraulic control valve 12 at this time and the hydraulic pressure (electric pump pressure P _E ) discharged from the electric oil pump 21 is as shown in FIG. That is, when the conditions for idle stop control are met and the vehicle speed becomes slower than a predetermined value (time t ₀ in FIG. 4), the control unit 15 prepares for the idle stop control as the vehicle speed decreases, so that the control unit 15 And the electric oil pump 21 is operated. Incidentally, the electric oil pump 21 is operated requires some time to until reaching the electric oil pump pressure P _E, the time t ₁ by the electric pump pressure P _E is actually the pressure in FIG. 4 in this embodiment Is starting to rise. On the other hand, when the vehicle speed further decreases from time t ₀ to a predetermined vehicle speed (time t ₁ in FIG. 4), the engine 2 is stopped. As a result, the output of the mechanical oil pump 20 decreases and the line pressure P _L decreases. When the electric pump pressure P _E reaches a predetermined value, that is, the hydraulic pressure P _{0 at} which the relief valve 40 is opened (time t ₂ in FIG. 4), the relief valve 40 is opened and hydraulic oil flows through the recirculation circuit. When the line pressure P _L and the electric pump pressure P _E matches (time t ₃ in FIG. 3, the hydraulic P _1), hydraulic fluid pressure control valve discharged from the electric oil pump 21 check valve 38 is opened 12 is supplied.

  As described above, since the viscosity of the hydraulic oil changes depending on the oil temperature, for example, when the electric oil pump 21 is torque controlled, when the oil temperature rises and the viscosity decreases, the electric oil pump 21, that is, The rotational speed of the electric motor 22 that drives the electric oil pump 21 increases, and the power consumption increases. Therefore, in the present embodiment, as shown in FIG. 3, the oil pan 31 is provided with an oil temperature sensor 42 for detecting the oil temperature of the working oil, and the detected value is input to the control unit 15 to control the oil. The unit 15 is configured to change the output voltage by controlling the DC-DC converter 14 according to the oil temperature. With this configuration, when the oil temperature of the hydraulic oil rises and the power consumption of the electric oil pump 21 increases, the output voltage of the DC-DC converter 14 is raised and more power is supplied to the pump driver 23. It becomes possible to supply.

  Now, two embodiments will be described as control for changing the output voltage of the DC-DC converter 14 by the control unit 15. The control unit 15 issues a command to the DC-DC converter converter 14 in consideration of the power consumption of the electric load connected to the 12V battery 24 including the electric oil pump 21 (electric motor 22) in normal operation. The output voltage is set to a predetermined range (for example, 12.5 V to 14.5 V), and is controlled so as to be an output voltage corresponding to these electric loads.

  In the first embodiment, as shown in FIG. 5, the control unit 15 changes the output voltage of the DC-DC converter 14 according to the state of the electric load and a high voltage (for example, 14.5V). A case is shown in which control is performed in two output modes, a fixed high mode.

  When the control unit 15 starts the idle stop control, the control unit 15 executes an output mode determination process of the DC-DC converter 14 shown in FIG. 6 at predetermined intervals. This output mode determination process is a process for determining how the control unit 15 controls the output voltage of the DC-DC converter 14. First, it is determined whether or not the electric oil pump 21 is driven. (S101). When the electric oil pump 21 is not driven, the command to the DC-DC converter 14 is set to the normal mode (S106). That is, the control unit 15 sets the output voltage of the DC-DC converter 14 according to the amount of power used by the electric load connected to the 12V battery 24. In FIG. 5, for simplicity of explanation, the output voltage of the DC-DC converter 14 in the normal mode is displayed as the lowest voltage (12.5 V), but from 12.5 V to 14 depending on the electric load. The DC-DC converter 14 is controlled by the control unit 15 so as to be an output voltage between .5V (output voltage in the high mode).

  On the other hand, when it is determined that the electric oil pump 21 is being driven (S101), it is determined whether or not the oil temperature sensor 42 is operating normally (S102), and it is determined that it is not operating normally. The control unit 15 continues the previous output mode (S104). Thereby, even if the oil temperature sensor 42 fails when the engine 2 is stopped by the idle stop control and the hydraulic oil is supplied by the electric oil pump 21, the electric oil pump 21 (electric motor 22) is stopped. Can operate the electric oil pump 21 by controlling the output voltage of the DC-DC converter 14 in the current output mode.

If the oil temperature sensor 42 is operating normally (S102), the output mode is determined based on the oil temperature detected from the oil temperature sensor 42 (S103). That is, when the oil temperature is equal to or higher than T ₁ or T ₂ , the output mode is set to the high mode (S105), and when it is lower than T ₁ or T ₂ , the normal mode is set (S106).

In the first embodiment, the relationship between the oil temperature of the hydraulic oil and the output mode of the DC-DC converter 14 has a hysteresis shape as shown in FIG. Therefore, in the determination processing of the oil temperature and the output mode (S103), when the current output mode is the high mode is determined by the working oil temperature T _1, when the output mode is the normal mode, hydraulic oil temperature judged by T _2. Thus, by making the relationship between the oil temperature and the output mode hysteresis, when the hydraulic oil is in the vicinity of the oil temperatures T ₁ and T ₂ for switching the output mode, the output mode is frequently changed with a slight oil temperature change. And the output voltage of the DC-DC converter 14 can be stabilized, that is, the electric oil pump 21 can be stably operated.

In the first embodiment described above, the case where the output mode when commanding the output voltage to the DC-DC converter 14 is changed according to the oil temperature of the hydraulic oil has been described. In the second embodiment, the DC- A case where the minimum voltage to be output by the DC converter 14 is set according to the oil temperature will be described. That is, as described above, the control unit 15 commands the output voltage to the DC-DC converter 14 in accordance with the electric load, and the minimum value of this output voltage (referred to as “minimum sustain voltage V _L ”) is hydraulic oil. It is a case where it comprised so that it might be determined according to the oil temperature.

In the second embodiment, the control unit 15, as shown in FIG. 7, in a predetermined temperature range (T ₁ through T _2), proportional to the change amount of the hydraulic oil temperature change amount of the minimum sustain voltage V _L Let This process will be described with reference to FIG. 8. When the control unit 15 starts the idle stop control, the control unit 15 executes a minimum sustain voltage determination process shown in FIG. 8 at predetermined intervals.

  In this minimum maintenance voltage determination process, it is determined whether or not the electric oil pump 21 is in operation (S201). When the electric oil pump 21 is not in operation, the output voltage is set to a predetermined value according to the electric load as described in the first embodiment. The normal mode commanded in a range (for example, 12.5 V to 14.5 V) is set (S205), and the DC-DC converter 14 is controlled.

  Next, it is determined whether or not the hydraulic sensor 42 is operating normally (S202). If the hydraulic sensor 42 is not operating normally, the control unit 15 continues the previous output mode (S203). Thereby, even if the oil temperature sensor 42 fails when the engine 2 is stopped by the idle stop control and the hydraulic oil is supplied by the electric oil pump 21, the electric oil pump 21 (electric motor 22) is stopped. Can operate the electric oil pump 21 by controlling the output voltage of the DC-DC converter 14 in the current output mode.

On the other hand, when it is determined that the hydraulic sensor 42 is operating normally (S202), the minimum maintenance voltage _VL is determined according to the hydraulic oil temperature detected by the hydraulic sensor 42 (S204), and the control unit 15 The output voltage of the DC-DC converter 14 is controlled according to the minimum sustain voltage V _L. For example, when the oil temperature and the minimum maintenance voltage V _L have the relationship shown in FIG. 7, when the oil temperature is lower than T ₁ , the minimum maintenance voltage V _{L is set} to 12.5 V, the oil temperature is equal to or higher than T ₁ and T ₂ When the temperature is smaller, the minimum maintenance voltage V _L is changed between 12.5 V and 14.5 V in proportion to the change in the oil temperature, and when the oil temperature is T ₂ or more, the minimum maintenance voltage V _{L is changed} to 14. 5V.

In this way, when the electric oil pump 21 is operated, the control unit 15 is configured to command the minimum value (minimum maintenance voltage V _L ) of the output voltage of the DC-DC converter 14 according to the oil temperature of the hydraulic oil. Thereby, sufficient electric power required according to the oil temperature can be supplied to the electric oil pump 21.

  By configuring the hydraulic pressure supply device 30 as in the first and second embodiments described above, the output voltage of the DC-DC converter 14 can be increased when the electric oil pump 21 is operated. An effect is obtained. First, it is possible to reduce the harness current on the upstream side of the pump driver 23, thereby suppressing heat generation, and reducing the capacity of fuses used in these electric circuits, thereby reducing the cost. Second, since the maximum electric power can be supplied to the pump driver 23, the pump performance of the electric oil pump 21 can be sufficiently exhibited even when the hydraulic oil temperature is high. Third, the output voltage of the DC-DC converter 14 does not affect the operation of the electric oil pump 21, that is, when the electric oil pump 21 is not operating or when the temperature of the operating oil is low. The fuel consumption can be improved by controlling the power according to the electric load.

1 is a block diagram illustrating a configuration of a traveling drive system of a hybrid vehicle in which a hydraulic pressure supply device according to the present invention is used. It is a block diagram which shows the drive circuit of the electric oil pump containing a DC-DC converter. It is a block diagram which shows the structure of the hydraulic pressure supply apparatus which concerns on this invention. It is a graph which shows transition of line pressure and electric pump pressure. It is a graph which shows the relationship between the oil temperature in 1st Example, and the output voltage of a DC-DC converter. It is a flowchart which shows the process of the control unit in 1st Example. It is a graph which shows the relationship between the oil temperature in 2nd Example, and the minimum output voltage of a DC-DC converter. It is a flowchart which shows the process of the control unit in 2nd Example.

Explanation of symbols

1 Hybrid vehicle (vehicle)
2 Engine (drive source)
4 Motor generator (drive source)
7 Automatic transmission mechanism (transmission mechanism)
8 Wheel 10 Battery (High voltage battery)
14 DC-DC converter (converter)
15 Control unit 20 Mechanical oil pump 21 Electric oil pump 22 Electric motor 24 12V battery (low voltage battery)
30 Hydraulic supply device 42 Oil temperature sensor V _L minimum maintenance voltage (minimum value of output voltage)

Claims (6)

Consisting of an engine and a motor generator connected in series, and a drive source for running the vehicle;
A high voltage battery for transferring power to and from the motor generator;
A mechanical oil pump driven by the drive source;
An electric motor driven by a low voltage battery;
An electric oil pump driven by the electric motor;
A speed change mechanism configured to set a speed change ratio by hydraulic oil supplied from the mechanical oil pump and the electric oil pump, and to change the rotational driving force of the drive source and transmit it to the wheels;
An oil temperature sensor for detecting the oil temperature of the hydraulic oil;
A converter that transforms the voltage of the high-voltage battery to charge the low-voltage battery;
A control unit for controlling the output voltage applied to the low-voltage battery of the converter by instructing the electric motor as a torque command value to actuate the electric motor to operate the electric motor;
The hydraulic pressure supply device, wherein the control unit is configured to control the output voltage according to the oil temperature detected by the oil temperature sensor.   2. The hydraulic pressure supply apparatus according to claim 1, wherein the control unit controls the converter so that the output voltage is maintained at a high voltage when the electric motor is operated.   The control unit controls the converter so that the output voltage is maintained at a high voltage when the oil temperature detected by the oil temperature sensor is equal to or higher than a predetermined value. 2. The hydraulic pressure supply device according to 2.   The control unit is configured to control the output voltage according to the amount of electric power used by an electric load connected to the low-voltage battery, and when the electric motor is operating, the oil temperature sensor 2. The hydraulic pressure supply device according to claim 1, wherein the converter is controlled not to fall below a minimum value of the output voltage determined according to the oil temperature detected by.   5. The control unit according to claim 1, wherein the control unit is configured to continue the current control on the converter until the electric motor is stopped when the oil temperature sensor fails. The hydraulic supply device according to the above. The hydraulic supply device according to claim 1, wherein the electric motor is a three-phase brushless sensorless motor.

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