JP4347315B2 - Hydraulic circuit of electric vehicle - Google Patents

Description

  The present invention relates to a hydraulic circuit of an electric vehicle.

As a vehicle drive system, one in which one side of a front wheel and a rear wheel is driven by a main drive source such as an engine and an auxiliary drive source by an electric motor is provided on the other side has been developed.
As a vehicle employing such a drive system, the front and rear wheels are driven by the main drive source during normal driving, and the auxiliary drive source is operated when starting on a rough road, for example, to drive the other wheel. What is communicated is known. In this vehicle, a hydraulic connecting / disconnecting device such as a hydraulic brake is provided in a power transmission mechanism that transmits power from a driving motor of an auxiliary drive source to wheels, and the connecting / disconnecting device is appropriately controlled according to the traveling state of the vehicle. To get. In the case of this vehicle, for example, when it is not necessary to drive or regenerate the motor, the power transmission is interrupted by the connecting / disconnecting device, so that the power loss due to the follower on the motor side can be reduced.

Further, as a control device for a hydraulic actuator such as the above-described connecting / disconnecting device, a device has been devised in which an accumulator is provided in an oil passage connected to the actuator to reduce power loss of the oil pump.
This actuator control device is provided with an accumulator in the oil passage on the actuator side, and a check valve that allows only oil to flow into the actuator side between the supply passage on the oil pump side and the oil passage on the actuator side. The oil pump is operated only when the pressure of the accumulator in the actuator-side oil passage decreases.
JP 2005-140323 A

  By the way, the above control device supplies the oil supplied from the oil pump only to the actuator side oil passage that requires high pressure, but the oil passage that requires a low pressure and large flow rate for lubrication or the like is used for the same oil pump. There is a request to share.

  Therefore, an oil path switching valve is provided for switching the supply path of the oil pump between a high pressure oil path that requires high pressure and a low pressure oil path that requires a low pressure and a large flow rate. It has been studied to operate a switching valve (see, for example, Patent Document 1). In this case, it is necessary to control the pump driving motor that drives the oil pump at the same time as the oil path is switched to adjust the supplied oil to an appropriate hydraulic pressure and flow rate. The low-pressure oil passage is provided with a pressure regulating valve for relieving oil when the hydraulic pressure increases.

  However, as shown in FIG. 13 (a), when switching from the low pressure oil passage to the high pressure oil passage, the pressure (line pressure) of the high pressure oil passage from the oil pump to the hydraulic brake suddenly increases. The load also increases rapidly, and the rotational speed of the oil pump decreases as shown in FIG. When the rotation speed falls below the lower limit of controllable speed, there is a problem that the electric oil pump steps out and becomes uncontrollable. As a countermeasure against this, it is conceivable to provide a position sensor in the pump driving electric motor, but this not only increases the weight and cost but also increases the size and adversely affects the mounting.

  In addition, the low-pressure oil passage is provided with a pressure regulating valve to relieve the internal oil when the oil pressure rises above the set pressure, so if the oil pressure reaches the set pressure, the pump rotation speed can be increased. There is a problem that the flow rate becomes constant and the flow rate adjustment range is narrow.

  Accordingly, it is an object of the present invention to provide a hydraulic circuit for an electric vehicle that can prevent the electric oil pump from stepping out and can freely adjust the flow rate of oil supplied to lubrication or the like. Is.

  In order to solve the above-described problem, an invention according to claim 1 includes an electric motor that generates a driving force of a vehicle (for example, electric motor 2 in the embodiment), the electric motor and a wheel (for example, rear wheel Wr in the exemplary embodiment), Between the hydraulic connecting / disconnecting means (for example, the hydraulic brake 28 in the embodiment) and accumulating means for accumulating the hydraulic pressure for operating the hydraulic connecting / disconnecting means (for example, An accumulator 42) in the embodiment, a first oil passage (for example, a high-pressure oil passage 90 in the embodiment) for supplying oil to the hydraulic connecting / disconnecting means and the pressure accumulating means, and a rotational difference between the left and right wheels of the wheel are absorbed. A second oil passage (for example, the lubricating oil passage 70 in the embodiment) for supplying oil to the differential device (for example, the differential device 13 in the embodiment), the electric motor branching from the second oil passage and the electric motor A third oil passage for supplying oil (for example, the cooling oil passage 71 in the embodiment) and an electric oil pump for supplying oil to the first oil passage, the second oil passage, and the third oil passage (for example, implementation) In the electric vehicle (for example, the vehicle 3 in the embodiment) provided with the oil pump 40 in the embodiment, the oil is connected to the first oil passage and the second oil passage, and oil from the electric oil pump is supplied to the second oil passage. An oil passage switching means (for example, a switching valve 56 in the embodiment) for switching whether to supply to the oil passage and the third oil passage, the oil passage switching means, the hydraulic connection / disconnection means, and the pressure accumulating means. A check valve (for example, a check valve 61 in the embodiment) provided therebetween, a control valve for controlling the operation of the oil passage switching means (for example, the control valve 55 in the embodiment), and the control valve Oil path switching means A pressure regulating valve that adjusts the flow rate of oil supplied to the second oil passage or the third oil passage when supplying oil to the second oil passage and the third oil passage (for example, the pressure regulating valve in the embodiment) 73), and the control valve controls a set pressure of the pressure regulating valve.

  According to a second aspect of the present invention, an orifice (for example, the orifice 72 in the embodiment) is disposed on either the downstream side of the branch point of the second oil passage with the third oil passage or the third oil passage. And the said pressure regulation valve is arrange | positioned in any other, It is characterized by the above-mentioned.

  The invention according to claim 3 is characterized in that the control valve applies hydraulic pressure to the oil passage switching means when supplying oil to the hydraulic connection / disconnection means and the pressure accumulating means.

  According to a fourth aspect of the present invention, there is provided a rotation difference detecting means (for example, the controller 110 in the embodiment) for detecting a rotation difference between left and right wheels of the wheel, an orifice is disposed in the second oil passage, and the control valve is The hydraulic pressure is applied to the pressure regulating valve when the rotation difference between the left and right wheels detected by the rotation difference detecting means is a predetermined value or more.

  According to the first aspect of the invention, the control valve controls the set pressure of the pressure regulating valve to adjust the flow rate of the oil supplied to the second oil passage and the third oil passage, so that the differential device and the electric motor The flow rate of the oil supplied to the can be freely adjusted according to demand.

  According to the second aspect of the invention, it is possible to adjust the flow rate of the oil passage in which the orifice is arranged by controlling the set pressure of the pressure regulating valve, and it is possible to control the rotational speed of the oil pump. It becomes possible to adjust the flow rate of the oil passage in which is arranged.

  According to the third aspect of the present invention, it is possible to linearly control the operation of the oil passage switching means by applying hydraulic pressure from the control valve to the oil passage switching means. This makes it possible to gradually increase the hydraulic pressure of the first oil passage that supplies oil to the hydraulic connection / disconnection means, and the rotational speed of the oil pump does not fall below the controllable speed lower limit. Can be prevented from stepping out.

  According to the fourth aspect of the present invention, when the difference between the left and right wheel rotations is equal to or greater than a predetermined value and a large amount of oil flow is required for lubricating the differential, the orifice is made by applying hydraulic pressure to the pressure regulating valve. The amount of lubricating oil supplied from the arranged third oil passage can be increased.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In this embodiment, the hydraulic circuit according to the present invention is applied to the hydraulic system provided in the drive device 1 for auxiliary driving of the vehicle 3 shown in FIG.

(Driver for electric vehicle)
First, the configuration of the vehicle 3 shown in FIG. 2 and the drive device 1 shown in FIG. 3 will be described.
A vehicle 3 shown in FIG. 2 is a hybrid vehicle having a drive unit 6 in which an internal combustion engine 4 and an electric motor 5 are connected in series, and the power of the drive unit 6 is transmitted to the front wheel Wf side via a transmission 7. The power of the driving device 1 for auxiliary driving provided separately from the driving unit 6 is transmitted to the rear wheel Wr side. The driving device 1 is driven by an electric motor 2 (wheel driving electric motor) composed of a DC brushless sensorless motor. The electric motor 5 of the driving unit 6 and the electric motor 2 of the rear wheel Wr side driving device 1 are connected to the battery 9 via a PDU 8 (power drive unit), and supply power from the battery 9 and from each of the electric motors 5 and 2 to the battery 9. Energy regeneration is performed via the PDU 8.

FIG. 3 is a longitudinal sectional view of the entire drive device 1. In FIG. 3, 10A and 10B are left and right axles on the rear wheel side of the vehicle. The housing 11 shown in FIG. 3 is formed in a substantially cylindrical shape as a whole, and includes an electric motor 2 for driving wheels, a planetary gear type speed reducer 12 for decelerating the driving rotation of the electric motor 2, and the speed reducer 12. The differential device 13 that distributes the output to the left and right axles 10A, 10B is accommodated and arranged so as to be coaxial with the axle 10B.
In the case of this embodiment, the planetary gear type speed reducer 12, the differential device 13 and the like constitute a power transmission device in the drive device 1.

  A stator 14 of the electric motor 2 is fixedly installed on the inner periphery of the end of the housing 11 on the wheel side (right side in FIG. 3), and an annular rotor 15 is rotatably accommodated and arranged on the inner peripheral side of the stator 14. . A cylindrical shaft 16 that surrounds the outer peripheral side of the axle 10B is coupled to the inner peripheral portion of the rotor 15. The cylindrical shaft 16 is connected to one end wall 17 and the intermediate wall 18 of the housing 11 so as to be coaxial with the axle 10B. It is supported via a bearing 19. A resolver 20 is provided between the outer periphery on one end side of the cylindrical shaft 16 and the end wall 17 of the housing 11 to feed back the rotation information of the rotor 15 to a control controller (not shown) of the electric motor 2. ing.

  The planetary gear type speed reducer 12 includes a sun gear 21, a plurality of planetary gears 22 meshed with the sun gear 21, a planetary carrier 23 that supports these planetary gears 22, and a ring gear 24 meshed with the outer peripheral side of the planetary gear 22. The driving force of the electric motor 2 is input from the sun gear 21, and the reduced driving force is output through the planetary carrier 23.

  The sun gear 21 is integrally formed on the outer periphery of a sleeve 25 coaxially disposed on the outer peripheral side of the axle 10B, and one end of the sleeve 25 is coupled to the cylindrical shaft 16 on the electric motor 2 side so as to be integrally rotatable. The planetary gear 22 includes a large-diameter first gear 26 that is directly meshed with the sun gear 21, and a second gear 27 that is smaller in diameter than the first gear 26. The first gear 26 and the second gear 27 Are integrally formed in a state of being coaxial and offset in the axial direction. The ring gear 24 is rotatably disposed at an axial side position of the first gear 26 in the housing 11, and an inner peripheral surface thereof meshes with a second gear 27 having a small diameter. The ring gear 24 is rotatably held integrally with a rotary drum 29 of a hydraulic brake 28 (hydraulic connection / disconnection device) described later, and is rotatably supported in the housing 11 via the rotary drum 29.

  On the other hand, the differential 13 includes a differential case 31 having a rotatable pinion 30 projecting on the inner surface side, and a pair of side gears 32a and 32b meshed with the pinions 30 and 30 in the differential case 31. The side gears 32a and 32b are coupled to the left and right axles 10A and 10B, respectively. The aforementioned planetary carrier 23 of the planetary gear type speed reducer 12 is integrally extended on the outer surface of the differential case 31. The differential case 31 is supported by the end wall 34 and the intermediate wall 18 on the vehicle body center side of the housing 11 via bearings 33.

  A cylindrical space is secured between the ring gear 24 and the end wall 34 in the housing 11, and a hydraulic brake (hydraulic connection / disconnection means) 28 is disposed in the space. In the hydraulic brake 28, a plurality of fixed plates 35 that are spline-fitted to the inner peripheral surface of the housing 11 and a plurality of rotary plates 36 that are spline-fitted to one outer peripheral surface of the rotary drum 29 are alternately arranged in the axial direction. These plates 35 and 36 are pressed and released by an annular piston 37. The piston 37 is accommodated in an annular cylinder chamber 38 formed on the end wall 34 of the housing 11 so as to be able to advance and retract. The piston 37 is advanced by introduction of high-pressure oil into the cylinder chamber 38, and the oil is discharged from the cylinder chamber 38. The piston 37 is moved backward by discharging the gas. The hydraulic brake 28 is connected to the hydraulic circuit 39 shown in FIG. 1, and the hydraulic circuit 39 will be described in detail later.

  In the case of the hydraulic brake 28 shown in FIG. 3, the fixed plate 35 is locked to the housing 11, while the rotating plate 36 integrally supports the ring gear 24. When pressed, a braking force is applied to the ring gear 24 by frictional engagement between the plates 35 and 36. When the pressure contact by the piston 37 is released from this state, the ring gear 24 is allowed to rotate freely.

  On the other hand, outside the end wall 17 on the wheel side of the housing 11, an accumulator (pressure accumulating means) 42 that stores oil in a preaccumulated state supplied to the hydraulic brake 28 is provided. In the accumulator 42, an annular volume chamber 51 having a depth in the axial direction is formed integrally with the inner peripheral edge of the end of the cover 43, and is fixed to the end wall 17 together with the cover 43. An annular piston 52 is accommodated in the volume chamber 51 so as to freely advance and retreat, and the piston 52 is urged by a pressure accumulation spring 53.

  When the axles 10A and 10B on the rear wheel Wr side are driven by the drive device 1 having the above configuration, oil is supplied from the oil pump 40 to the hydraulic brake 28 to turn on the brake 28, and the fixed plate 35 and the rotating plate The ring gear 24 is fixed to the housing 11 by frictionally engaging 36. When the ring gear 24 is thus fixed, the reduction ratio of the planetary gear type reduction gear 12 is fixed, and the driving force is transmitted between the sun gear 21 and the planetary carrier 23. Accordingly, at this time, the driving force of the electric motor 2 is reduced to the set reduction ratio by the planetary gear type reduction gear 12 and transmitted to the left and right axles 10A and 10B through the differential device 13.

When the driving device 1 does not generate a driving force for the vehicle, the power path between the wheels and the electric motor 2 can be disconnected by opening the hydraulic brake 28 and releasing the braking of the ring gear 24. .
Therefore, in the drive device 1, it is possible to prevent excessive rotation of the electric motor 2 and suppress drag loss of the electric motor 2.

(Hydraulic circuit)
Here, the hydraulic circuit 39 shown in FIG. 1 will be described. The hydraulic circuit 39 employs the hydraulic circuit of the electric vehicle according to the present invention.
The hydraulic circuit 39 connects the oil discharged from the oil pump 40 to the high-pressure oil passage 90 via a switching valve (oil passage switching means) 56 that is controlled by a linear solenoid (control valve) 55, and low-pressure oil. Whether or not to supply to the path 57 can be switched. The high-pressure oil passage 90 constitutes a first oil passage in the present invention together with a brake-side oil passage 58 that supplies oil to the hydraulic brake 28 and a branch oil passage 60 that supplies oil to the accumulator. The low pressure oil passage 57 is an oil passage that requires a low pressure and a large flow rate for lubrication and cooling, and constitutes the second oil passage and the third oil passage in the present invention.

  The oil pump 40 is constituted by a gear pump or the like, and is driven by a pump driving motor 41. A pump oil passage 111 extends from the oil pump and is connected to the switching valve 56. A high-pressure oil passage 90 extends from the switching valve 56 and is connected to a brake-side oil passage 58. A check valve 61 is interposed in the high-pressure oil passage 90 to prevent backflow of oil from the brake-side oil passage 58 toward the switching valve 56.

  A brake operation valve 59 made of an electromagnetic valve is interposed in the brake side oil passage 58. The brake operation valve 59 is composed of an electromagnetic three-way valve controlled by the controller 110. When the solenoid is energized, the branch oil passage 60 that is connected to the accumulator 42 is connected to the hydraulic brake 28 to engage the brake 28. When the energization of the solenoid is stopped, the connection with the branch oil passage 60 is cut off and the hydraulic brake 28 is connected to the drain port 117 to release the engagement of the hydraulic brake 28.

  A branch oil passage 60 that communicates with the accumulator 42 is provided upstream of the brake operation valve 59. The pressure of the accumulator 42 is maintained between the pressure accumulation start pressure AL and the pressure accumulation completion pressure AH. The pressure accumulation start pressure AL is set to a pressure close to the lower limit value of the hydraulic pressure that can ensure the necessary torque transmission capacity of the hydraulic brake. Further, the pressure accumulation completion pressure AH of the accumulator 42 is higher than the pressure accumulation start pressure AL, and is set to a pressure that can ensure the operation of the hydraulic brake 28 for a certain period of time. The branch oil passage 60 is provided with a pressure sensor 62 for monitoring the pressure of the accumulator 42, and a detection signal of the pressure sensor 62 is input to the controller 110 (ECU).

  FIG. 4 is an explanatory diagram of the switching valve. The switching valve 56 includes a spool 112 that allows the pump oil passage 111 to communicate with the high-pressure oil passage 90 and communicates with the low-pressure oil passage 57. As shown in FIG. 4, when the spool 112 is located at the left end, the pump oil passage 111 communicates only with the high-pressure oil passage 90 and is cut off from the low-pressure oil passage 57, and when the spool 112 moves to the right end, the pump oil passage 111 Is communicated with the high pressure oil passage 90 and the low pressure oil passage 57. The spool 112 is urged to the left in FIG. Further, the pressure of the pump oil passage 111 acts on the left end surface of the spool 112 in the drawing through a back pressure passage 114, and the output from the control valve passes through the pilot passage 115 on the right end surface in the drawing. Pressure is applied.

  FIG. 5 is an explanatory diagram of the control valve. The control valve 55 is configured by a linear solenoid valve, and includes a spool 122 that communicates and blocks the high-pressure oil passage 90 with respect to the pilot passage 115. As shown in FIG. 5, when the spool 122 is located at the center, the high-pressure oil passage 90 is blocked from the pilot passage 115, and when the spool 122 moves to the left side, the high-pressure oil passage 90 communicates with the pilot passage 115. ing. When the spool 122 moves to the right side, the pilot passage 115 communicates with the drain port m. The position of the spool 122 is controlled by energizing a linear solenoid that constitutes the control valve 55. Note that the pressure of the pilot passage 115 acts on the left end surface of the spool 122 in the drawing via the back pressure passage 125.

  On the other hand, the low-pressure oil passage 57 shown in FIG. 1 branches into a lubricating oil passage 70 and a cooling oil passage 71. The lubricating oil passage 70 supplies oil as lubricating oil to the lubricating portion of the power transmission device (the speed reducer 12 and the differential device 13), and the cooling oil passage 71 is a cooling portion (requiring cooling) of the wheel driving motor 2. Oil is supplied to the part) as cooling oil. The lubricating oil passage 70 is provided with an orifice 72, and the cooling oil passage 71 is provided with a pressure regulating valve 73.

  FIG. 6 is an explanatory diagram of the pressure regulating valve. The pressure regulating valve 73 includes a spool 79 that communicates and blocks the low-pressure oil passage 57 with respect to the cooling oil passage 71. As shown in FIG. 6, when the spool 79 is located at the left end, the low pressure oil passage 57 is blocked from the cooling oil passage 71, and when the spool 79 moves to the right, the low pressure oil passage 57 communicates with the cooling oil passage 71. It has become. The spool 79 is urged to the left in FIG. Further, the pressure of the low pressure oil passage 57 acts on the left end surface of the spool 79 in the drawing through the back pressure passage 84, and the output from the control valve passes through the pilot passage 115 on the right end surface in the drawing. Pressure is applied.

  On the other hand, the controller 110 shown in FIG. 1 selects an oil path selection means 120 for selecting whether or not the oil discharged from the oil pump 40 is supplied to the low pressure oil path 57, and the selection result of the oil path selection means 120. Accordingly, a control means 121 for controlling the operation of the control valve 55 is provided. In the case of this embodiment, the oil passage selection means 120 receives a pressure signal from the pressure sensor 62 in the branch oil passage 60 and selects whether to supply oil to the low pressure oil passage 57 based on the signal. Based on the selection result, the control means 121 controls the operation of the control valve 55. The switching valve 56 is driven by the output pressure from the control valve 55 to switch whether or not to supply oil to the low pressure oil passage 57.

An oil temperature sensor 123 that detects the temperature of the oil and a wheel speed sensor 122 that independently detects the rotational speed of the rear wheels of the vehicle are connected to the input side of the oil path selection means 120. An oil passage selection unit 120 receives the detection signal from the wheel speed sensor 122, the absolute value of the difference between the wheel speed R _R of the wheel speed R _L and the right rear wheel of the vehicle left rear wheel | R L _-R R _| a calculate. That is, the oil path selection unit 120 functions as a rotation difference detection unit. Based on the calculation result, the control means 121 controls the operation of the control valve 55. The set pressure of the pressure regulating valve 73 is changed by the output pressure from the control valve 55 so that the amount of lubricating oil is adjusted.

(Hydraulic circuit operation)
Next, the operation of the hydraulic circuit 39 shown in FIG. 1 will be described. The hydraulic circuit 39 is operated in a Hi mode for supplying high pressure oil to the high pressure oil passage 90 and a Low mode for supplying low pressure oil to the low pressure oil passage 57.
When the vehicle is started, the spool 112 of the switching valve 56 is urged to the left in the drawing by the spring 113. At this time, the inflow port a from the pump oil passage 111 communicates with the outflow port b to the high pressure oil passage 90 and is blocked from the outflow port c to the low pressure oil passage 57. As a result, the pressure in the high-pressure oil passage 90 flows into the left end of the spool 112 via the back pressure passage 114 and the back pressure port d. On the other hand, the inflow port e from the high pressure oil passage 90 in the control valve 55 is blocked from the outflow port f to the pilot passage 115. Therefore, the operation pressure from the control valve 55 does not act on the right end surface of the spool 112 of the switching valve 56. Therefore, after the left end of the spool 112 is filled with a predetermined pressure, the spool 112 moves to the right.

When the spool 112 of the switching valve 56 moves to the right side, the inflow port a from the pump oil passage 111 communicates with the outflow port c to the low pressure oil passage 57. As a result, oil is supplied from the pump oil passage 111 to the low pressure oil passage 57, and the hydraulic circuit 39 is operated in the Low mode.
In the Low mode, oil is supplied from the low pressure oil passage 57 to the lubricating oil passage 70 via the orifice 72. The oil in the low pressure oil passage 57 flows into the left end of the spool 79 via the back pressure passage 84 and the back pressure port j. When the left end of the spool 79 is filled with a predetermined pressure, the spool 79 urged to the left in the drawing by the spring 89 moves to the right in the drawing. As a result, the inflow port i from the low pressure oil passage 57 communicates with the outflow port k to the cooling oil passage 71, and oil is supplied from the low pressure oil passage 57 to the cooling oil passage 71.

  The oil flow rate (lubricating oil amount) in the lubricating oil passage 70 is adjusted by adjusting the output pressure from the control valve (the hydraulic pressure in the pilot passage 115). Specifically, when an instruction to increase the amount of lubricating oil is input to the controller 110, the control unit 121 outputs a control signal to the control valve 55. Based on this control signal, the control valve 55 moves the spool 122 to the left side in the figure to connect the inflow port e from the high pressure oil passage 90 and the outflow port f to the pilot passage 115. As a result, oil is supplied from the high-pressure oil passage 90 to the pilot passage 115.

  The hydraulic pressure of the pilot passage 115 acts on the left side surface of the spool 122 via the back pressure port g. When the back pressure becomes larger than the driving force of the spool 122 by the control valve 55, the spool 122 moves to the right side. As a result, the outflow port f to the pilot passage 115 and the drain port m communicate with each other, and the hydraulic pressure in the pilot passage 115 decreases. Thus, the hydraulic pressure of the pilot passage 115 (the output pressure from the control valve 55) is fed back to the control valve 55 and balanced with the driving force of the linear solenoid, thereby linearly controlling the output pressure from the control valve 55. Can do.

  The output pressure (operating pressure) from the control valve 55 acts on the operating pressure port n of the switching valve 56 and also acts on the operating pressure port h of the pressure regulating valve 73. When the operation pressure acts on the right side surface of the spool 79 of the pressure regulating valve 73, the spool 79 moves to the left side in the figure, and oil supply from the low pressure oil passage 57 to the cooling oil passage 71 is restricted. Since the set pressure of the pressure regulating valve 73 is set lower than the set pressure of the switching valve 56, the spool 112 of the switching valve 56 does not move even if the spool 79 of the pressure regulating valve 73 moves, and the flow rate of the low pressure oil passage 57. Is maintained. Therefore, by increasing the output pressure from the control valve 55, the amount of oil supplied from the low pressure oil passage 57 to the lubricating oil passage 70 is increased, and the amount of lubricating oil supplied to the differential device or the like can be increased. it can.

  The oil flow rate (cooling oil amount) in the cooling oil passage 71 is adjusted by controlling the rotational speed of the oil pump 40. When the rotational speed of the oil pump 40 is increased, the amount of oil supplied from the pump oil passage 111 to the low-pressure oil passage 57 increases. As a result, the amount of oil supplied from the low pressure oil passage 57 to the cooling oil passage 71 is increased, and the amount of cooling oil supplied to the electric motor or the like can be increased.

  On the other hand, switching from the Low mode to the Hi mode is performed by controlling the output pressure of the control valve 55 and increasing the hydraulic pressure of the high-pressure oil passage 90 to a predetermined pressure. Specifically, the control valve 55 increases the amount of oil supplied from the high-pressure oil passage 90 to the pilot passage 115 based on the control signal output from the control means 121. The hydraulic pressure (operating pressure) of the pilot passage 115 acts on the right end surface of the spool 112 via the operating pressure port n of the switching valve 56. When this operating pressure rises, the spool 112 moves to the left in the figure, and the oil flow rate from the pump oil passage 111 to the high pressure oil passage 90 increases. As a result, the hydraulic pressure in the high pressure oil passage 90 can be increased.

  FIG. 7 is an explanatory diagram of the switching operation from the Low mode to the Hi mode. In order to increase the hydraulic pressure of the high-pressure oil passage 90 to the predetermined pressure AH, it is necessary to increase the hydraulic pressure (EOP discharge pressure) of the pump oil passage 111 to AH. According to FIG. 7D, in order to increase the EOP discharge pressure to AH, it is necessary to supply a drive current (solenoid current) Imax to the control valve 55. Therefore, as shown in FIG. 7A, the solenoid current is gradually increased to Imax. Then, as shown in FIG. 7B, the EOP discharge pressure gradually increases to AH. By gradually increasing the EOP discharge pressure in this way, as shown in FIG. 7C, the EOP rotation speed (number of rotations) can be switched from the Low mode to the Hi mode without falling below the controllable speed lower limit. Can be executed.

  When the EOP discharge pressure increases to AH, the mode returns from the Hi mode to the Low mode. Specifically, the supply of the solenoid current to the control valve 55 is stopped, and the pump oil passage 111 is connected to the low-pressure oil passage 57 in the switching valve 56. As a result, the EOP discharge pressure decreases, but since the check valve 61 is provided between the pump oil passage 111 and the brake side oil passage 58 as shown in FIG. Does not drop immediately.

(Control flow)
Next, the control flow by the controller will be described with reference to FIG. 1 and FIG. FIG. 8 is a flowchart of control by the controller.
First, in S101, the detection signal from the pressure sensor 62 is received, and the pressure Poil of the accumulator 42 is detected. The oil temperature sensor 123 receives the detection signal from the oil temperature sensor 123 and detects the oil temperature Toil.

  Next, in S103, the oil passage selection unit 120 determines whether or not the pressure Poil of the accumulator 42 exceeds the upper limit set pressure AH. When it exceeds, it progresses to S104 and the control means 121 sets the control valve 55 to Low mode. On the other hand, when the pressure Poil of the accumulator 42 does not exceed the upper limit set pressure AH, the process proceeds to S105. Here, the oil passage selection means 120 determines whether or not the pressure Poil of the accumulator 42 is lower than the lower limit set pressure AL. At this time, if the pressure Poil is lower than the lower limit set pressure AL, the process proceeds to S106, the control means 121 sets the control valve 55 to the Hi mode, and if not lower than the lower limit set pressure AL, the process proceeds to S107. The control valve 55 is set to the same mode as the current mode.

  Even if the process proceeds to any step of S104, S106, and S107, after these processes, the process proceeds to S109, and in the subsequent steps, different controls are executed in accordance with each mode set in the previous stage and other vehicle conditions. To do.

  In S109, the oil passage selection means 120 determines whether or not the control valve 55 is set to the Hi mode. If it is determined that the Hi mode is set, the process proceeds to S110, and the solenoid current increment ΔI is read from the ΔI map. Further, in S111, the increment ΔI is added to the current solenoid current Isol. The increment ΔI is repeated until the solenoid current Isol reaches Imax described above. The added solenoid current Isol is output to the control valve 55 by the control means 121.

  FIG. 9A is a ΔI map. In the ΔI map, the increment ΔI is set to increase as the oil temperature Toil increases. This is because the higher the oil temperature Toil, the lower the viscosity of the oil. Therefore, when the oil is supplied to the hydraulic brake 28 and the accumulator 42, the fluctuation of the load applied to the electric oil pump is small, and conversely, the lower the oil temperature Toil is. Because the viscosity of the oil increases, the fluctuation of the load applied to the electric oil pump becomes large. In this way, ΔI varies according to Toil, that is, the fluctuation of the load applied to the electric oil pump according to the viscosity of the oil. By adjusting, the step-out of the electric oil pump can be prevented.

Returning to FIG. 8, if it is determined in S109 that the Hi mode is not set, the process proceeds to S120. In S120, the oil passage selecting means 120 receives a detection signal from the wheel speed sensor 122, for detecting a wheel speed R _R of the wheel speed R _L and the right rear wheel of the vehicle left rear wheel. Next, in S121, the absolute value | R _L −R _R | of the difference between R _L and R _R is calculated. Next, in S123, | R _L −R _R | is compared with a predetermined value ΔV to determine whether or not the rotation difference between the left and right rear wheels is small. When it is determined that | R _L −R _R | <ΔV is established, the process proceeds to S124, and when it is determined that | R _L −R _R | <ΔV is not established, the process proceeds to S127.

  In S124, the control valve 55 is set to the normal lubrication mode when the difference in rotation between the left and right rear wheels is small, such as when the vehicle is traveling straight, and the need for lubrication of the differential 13 is small. Specifically, the solenoid current is set to Isol = 0 and output from the control means 121 to the control valve 55. In this case, the output pressure from the control valve 55 becomes 0, and no operating pressure acts on the operating pressure port h of the pressure regulating valve 73. As a result, the ratio of the lubricating oil amount to the cooling oil amount becomes relatively small.

On the other hand, in S126, the control valve 55 is set to the differential rotation lubrication mode when the difference in rotation between the left and right rear wheels is large, such as when the vehicle is turning, and the need for lubrication of the differential 13 is large. Specifically, the oil passage selection means 120 reads the solenoid current Isol from the Isol map and outputs it from the control means 121 to the control valve 55.
FIG. 9B is an Isol map. In the Isol map, the solenoid current Isol is set to increase as the rotation difference | R _L −R _R | between the left and right rear wheels increases. The control valve 55 outputs an operation pressure proportional to the solenoid current Isol, and acts on the operation pressure port h of the pressure regulating valve 73. As a result, the ratio of the lubricating oil amount to the cooling oil amount can be increased, and damage to the differential device 13 can be prevented.

  As described above in detail, the hydraulic circuit of the electric vehicle according to the present embodiment is connected to the high-pressure oil passage 90 and switches whether to supply the oil from the oil pump 40 to the low-pressure oil passage 57 or not. A valve 56, a check valve 61 provided between the switching valve 56, the hydraulic brake 28 and the accumulator 42, a control valve 55 for controlling the operation of the switching valve 56, and the control valve 55. A pressure regulating valve 73 that adjusts the flow rate of the oil supplied to the lubricating oil passage 70 or the cooling oil passage 71 branched from the low pressure oil passage 57 when supplying the oil to the passage 57. The set pressure of the pressure valve 73 is controlled. According to this configuration, the control valve 55 controls the set pressure of the pressure regulating valve 73, whereby the flow rate of oil supplied to the lubricating oil passage 70 and the cooling oil passage 71 can be adjusted. Therefore, the amount of lubricating oil can be freely adjusted as required.

  Further, the orifice 72 is arranged in the lubricating oil passage 70 and the pressure regulating valve 73 is arranged in the cooling oil passage 71. According to this configuration, the flow rate of the lubricating oil passage 70 can be adjusted by controlling the set pressure of the pressure regulating valve 73, and the flow rate of the cooling oil passage 71 can be controlled by controlling the rotational speed of the oil pump 40. Can be adjusted.

  Further, the oil path selection means 120 detects the difference between the left and right wheel rotations of the wheel, and supplies the oil from the control valve 55 to the pressure regulating valve 73 when the detected left and right wheel rotation difference is equal to or greater than a predetermined value. According to this configuration, the orifice 72 is disposed by supplying oil to the pressure regulating valve 73 when the difference in rotation between the left and right wheels is equal to or greater than a predetermined value and a large oil flow rate is required for lubricating the differential device 13. The amount of lubricating oil supplied from the lubricating oil passage 70 can be increased.

  On the other hand, the hydraulic circuit of the electric vehicle according to the present embodiment is configured to increase the oil supplied from the control valve 55 to the switching valve 56 in a stepwise manner when supplying oil to the hydraulic brake 28 and the accumulator 42. According to this configuration, the oil pressure of the high-pressure oil passage 90 that supplies oil to the hydraulic brake 28 can be gradually increased, and the rotational speed of the oil pump 40 does not fall below the controllable speed lower limit. The step-out of the pump 40 can be prevented.

  FIG. 10 is a hydraulic circuit diagram according to a first modification of the present embodiment. In the present embodiment described above, the output pressure of the control valve 55 is used as the operating pressure of the pressure regulating valve 73. However, in the first modification, the line pressure of the high pressure oil passage 90 is used as the operating pressure of the pressure regulating valve 73. This is because the output pressure of the control valve 55 is also used for the operation pressure of the switching valve 56, and therefore the line pressure that is the output pressure of the switching valve 56 is controlled by the control valve 55. Even in this case, the set pressure of the pressure regulating valve 73 can be controlled by the control valve 55, and the amount of lubricating oil can be controlled as required.

  FIG. 11 is a hydraulic circuit diagram according to a second modification of the present embodiment. In the present embodiment described above, the control valve 55 is constituted by a linear solenoid valve, and the line pressure is used as the operation pressure of the pressure regulating valve 73 in the first modification. Instead, in the second modification, the switching valve 56 is configured by a linear solenoid valve, and the line pressure is used as the operation pressure of the pressure regulating valve 73. If the control valve 55 is configured with a linear solenoid valve and the set pressure of the switching valve is linearly controlled with the output pressure, the switching valve 56 can be configured with a linear solenoid valve and the set pressure can be linearly controlled. It is. According to this configuration, it is possible to reduce the cost by omitting the control valve.

  FIG. 12A is a hydraulic circuit diagram according to a third modification of the present embodiment. In the present embodiment described above, the control valve 55 is configured by a linear solenoid valve. However, in the third modification, the control valve 55 is configured by an ON / OFF solenoid valve, and its duty ratio (operation rate) is controlled. FIG. 12B is a graph showing the relationship between the duty ratio of the ON / OFF solenoid valve and the output pressure. The practical range of the duty ratio of the ON / OFF solenoid valve is between about 35% and about 75%. When the duty ratio of the ON / OFF solenoid valve increases within the range, the oil flows from the high pressure oil passage 90 into the pilot passage 115, and the output pressure increases. Therefore, by supplying a solenoid current so as to have a duty ratio corresponding to a desired output pressure, the same effects as in the present embodiment can be obtained.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment, the control device according to the present invention is applied to the hydraulic circuit 39 provided with the brake control oil passage and the cooling / lubrication oil passage inside the auxiliary drive device 1. The application of the present invention is not limited to the driving device 1, and can be applied to other devices as long as the device has a hydraulic circuit having an oil passage that requires high pressure and an oil passage that requires a low pressure and a large flow rate. is there.

  In the above embodiment, the oil passage selection means 120 in the controller 110 supplies the oil from the oil pump 40 based on the pressure of the high-pressure oil passage 90 that is the first oil passage (pressure of the accumulator 42). Whether to supply to the low-pressure oil passage 57 is switched. However, depending on the application application of the hydraulic circuit, the flow rate on the low-pressure oil passage 57 side, which is the second oil passage that requires a low pressure and large flow rate, is determined. Thus, it may be switched whether or not the oil from the oil pump 40 is supplied to the low pressure oil passage.

It is a schematic block diagram of the hydraulic circuit of the electric vehicle which concerns on embodiment. 1 is a schematic configuration diagram of a vehicle. It is a longitudinal cross-sectional view of a drive device. It is a schematic block diagram of a switching valve. It is a schematic block diagram of a control valve. It is a schematic block diagram of a pressure regulation valve. It is explanatory drawing of switching operation from Low mode to Hi mode. It is a flowchart of control by a controller. A ΔI map and an Isol map. It is a hydraulic circuit figure concerning the 1st modification of an embodiment. It is a hydraulic circuit figure concerning the 2nd modification of an embodiment. It is a hydraulic circuit figure concerning the 3rd modification of an embodiment. It is explanatory drawing of switching operation from Low mode to Hi mode in a prior art.

Explanation of symbols

  Wr ... Rear wheel 2 ... Electric motor 3 ... Vehicle 13 ... Differential device 28 ... Hydraulic brake (hydraulic connection / disconnection means) 40 ... Oil pump 55 ... Control valve 56 ... Switch valve (oil path switching means) 57 ... Low pressure oil path 70 ... Lubricating oil passage 71 ... Cooling oil passage 72 ... Orifice 73 ... Pressure regulating valve 90 ... High-pressure oil passage 110 ... Controller

Claims (4)

An electric motor that generates a driving force for the vehicle, a hydraulic connecting / disconnecting means that connects and disconnects the driving force of the electric motor provided between the electric motor and wheels, and accumulates hydraulic pressure for operating the hydraulic connecting / disconnecting means A first oil path for supplying oil to the pressure accumulating means, the hydraulic connecting / disconnecting means and the pressure accumulating means, and a second oil path for supplying oil to a differential device that absorbs the rotational difference between the left and right wheels of the wheel; A third oil passage that branches from the second oil passage and supplies oil to the electric motor; and an electric oil pump that supplies oil to the first oil passage, the second oil passage, and the third oil passage. In electric vehicles,
An oil passage switching means that is connected to the first oil passage and the second oil passage, and that switches whether oil from the electric oil pump is supplied to the second oil passage and the third oil passage;
A check valve provided between the oil path switching means and the hydraulic connection / disconnection means and the pressure accumulating means;
A control valve for controlling the operation of the oil passage switching means;
When the oil passage switching means supplies oil to the second oil passage and the third oil passage by the control valve, the flow rate of oil supplied to the second oil passage or the third oil passage is adjusted. A pressure regulating valve,
The hydraulic valve for an electric vehicle, wherein the control valve controls a set pressure of the pressure regulating valve.   The orifice is arranged on either the downstream side of the branch point of the second oil passage with the third oil passage or on the third oil passage, and the pressure regulating valve is arranged on the other. Item 2. A hydraulic circuit for an electric vehicle according to Item 1.   3. The electric vehicle according to claim 1, wherein the control valve applies hydraulic pressure to the oil path switching unit when supplying oil to the hydraulic connection / disconnection unit and the pressure accumulating unit. Hydraulic circuit. A rotation difference detection means for detecting a difference in rotation between the left and right wheels of the wheel;
Arranging an orifice in the second oil passage;
The electric motor according to any one of claims 1 to 3, wherein the control valve applies a hydraulic pressure to the pressure regulating valve when a difference in rotation between the left and right wheels detected by the rotation difference detecting means is a predetermined value or more. The hydraulic circuit of the vehicle.

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