JP4900682B2 - Hydraulic supply device - Google Patents

Description

  The present invention relates to a hydraulic pressure supply device provided in a vehicle, and more specifically, a transmission system that transmits power from an engine to a travel drive system via a hydraulic transmission mechanism, and a mechanical hydraulic pump that is driven by the power of the engine. And an electric hydraulic pump driven by an electric motor, a control oil path for supplying hydraulic oil from one of the mechanical hydraulic pump and the electric hydraulic pump to the transmission mechanism, and driving the electric hydraulic pump when the engine is stopped The present invention relates to a technique for radiating hydraulic fluid in a hydraulic pressure supply device including a control unit that maintains the supply of hydraulic fluid to the transmission mechanism.

  Control to stop the engine when the vehicle is stopped (idle stop control) in order to reduce CO2 and improve fuel efficiency, or stop the engine in situations where hybrid vehicles do not require driving power or charging power There are vehicles that perform control. In this type of vehicle, a hydraulic pump driven by an engine (mechanical hydraulic pump in the present invention), a hydraulic pump driven by an electric motor (electric hydraulic pump in the present invention), and hydraulic oil from these hydraulic pumps By providing a hydraulic system that supplies the transmission mechanism to the transmission mechanism, when the engine is stopped, hydraulic oil from the electric hydraulic pump is supplied to the transmission mechanism, and, for example, a shift operation such as maintaining a transmission state even when the vehicle is stopped is realized. It is configured as follows.

  For example, in Patent Document 1, a transmission system that transmits the driving force of an engine to a transmission mechanism (in the literature, a continuously variable automatic transmission mechanism) is provided, and the engine is driven by the engine to supply hydraulic oil to the transmission mechanism. A mechanical hydraulic pump (in the literature, a mechanical pump), an electric hydraulic pump driven by a battery (in the literature, an electric pump), and a control unit (in the literature, a controller) for controlling them. The control unit stops the running of the vehicle, reaches an idling state, establishes a condition for automatically stopping the engine, and executes the automatic engine stop when the delay period has elapsed. The electric hydraulic pump starts to operate before the automatic engine stop control is performed, and the pressure of the hydraulic oil supplied from the electric hydraulic pump is gradually increased and required before the automatic engine stop is performed. Supply hydraulic fluid with pressure. In addition, when the engine is restarted, the control mode is set so that the electric hydraulic pump is stopped after the hydraulic oil pressure from the mechanical hydraulic pump rises to a sufficient value.

  Thus, a hybrid vehicle can be mentioned as an example of operating the electric hydraulic pump when the engine is stopped. As an example, Patent Document 2 discloses a mechanical hydraulic pump (a main oil pump in the literature) that is provided with a speed change mechanism (a transmission device in the literature) that transmits power from an engine and a motor generator to wheels, and an electric motor. It includes an electric hydraulic pump (electric oil pump in the literature) driven by a motor, and a control unit (ECU in literature) that controls the engine, the transmission mechanism, and the electric hydraulic pump. This control unit drives the electric hydraulic pump when the engine is stopped to realize the supply of hydraulic oil.

  In addition, the following is a description of what dissipates hydraulic oil. Patent Document 3 includes a transmission system that transmits the driving force of the engine to a transmission mechanism (automatic transmission in the literature), and stops the engine when the vehicle stops. A control unit (ECU, idling stop system in the literature) that restarts the engine when a predetermined condition is satisfied is provided. In order to supply hydraulic oil to the transmission mechanism, a mechanical hydraulic pump (mechanical pump in the literature) driven by an engine and an electric hydraulic pump (electric pump in the literature) are provided. The transmission mechanism includes a torque converter, a lockup clutch, a plurality of friction elements, and a lubrication circuit. The hydraulic fluid (fluid in the literature) from the mechanical hydraulic pump or electric hydraulic pump is supplied to the torque converter and the friction element for shifting through the corresponding valve, and the hydraulic fluid (fluid) sent from the torque converter is Supplied to an oil cooler that dissipates heat.

  The oil path system for supplying hydraulic oil from the mechanical hydraulic pump or the electric hydraulic pump shown in Patent Document 3 to the transmission is similar to the oil path system shown in Patent Document 1. However, the oil path system of Patent Document 3 is different from the oil path system of Patent Document 1 in that the electric hydraulic pump is controlled based on a state change in the oil path system. More specifically, for example, in the apparatus of Patent Document 3, the hydraulic oil is cooled or heated by operating the electric hydraulic pump based on the temperature of the hydraulic oil (fluid), and as much as at the time of shifting. The control mode is set so as to operate the electric hydraulic pump even when the hydraulic oil is required.

JP 2001-41067 A (paragraph numbers [0020] to [0047], FIGS. 1 to 10) JP-A-11-287316 (paragraph numbers [0023] to [0025], [0038], FIGS. 1 and 2) JP-A-2004-286148 (paragraph numbers [0015] to [0050], FIGS. 1 to 7)

  As described above, what supplies hydraulic fluid from the electric hydraulic pump to the transmission mechanism when the engine is stopped is required for both a vehicle that performs idling stop and a hybrid vehicle. In addition, as described in Patent Document 3, it is also necessary to cool the hydraulic oil. However, as described in Patent Document 3, cooling is performed by increasing the amount of hydraulic oil supplied from the electric hydraulic pump to the torque converter and increasing the amount of hydraulic oil sent from the torque converter to the oil cooler. In the realization, a wasteful load acts on the electric hydraulic pump, and there is room for improvement.

  An object of the present invention is to configure a hydraulic pressure supply device that rationally realizes cooling of hydraulic oil by utilizing a configuration having a mechanical hydraulic pump driven by an engine and an electric hydraulic pump driven by an electric motor. It is in.

A feature of the present invention is that a transmission system that transmits power from an engine to a travel drive system via a hydraulic transmission mechanism, a mechanical hydraulic pump that is driven by the power of the engine, and an electric hydraulic pump that is driven by an electric motor A control oil path for supplying hydraulic oil from one of the mechanical hydraulic pump and the electric hydraulic pump to the transmission mechanism, and supplying the hydraulic oil to the transmission mechanism by driving the electric hydraulic pump when the engine is stopped And a control unit for maintaining
A heat dissipating oil passage for guiding the working oil sent from the electric hydraulic pump to an oil cooler is formed, and a supply position for supplying the working oil from the electric hydraulic pump to the heat dissipating oil passage and a shut-off position for shutting off the working oil. And a switching valve for setting the switching valve to the supply position in a situation where the engine is operated.
A temperature sensor for measuring the temperature of the hydraulic oil is provided, and when it is determined that the temperature measured by the temperature sensor exceeds a preset value, a heat dissipation control means for operating the electric hydraulic pump is provided ,
The switching valve is configured to include a spool that is operable between the supply position and the shut-off position, and the valve switching means is operated from a spring that biases the spool to the shut-off position and from the mechanical hydraulic pump. And an operating oil passage that operates the spool in the direction of the supply position by causing oil to act against the biasing force of the spring .

With this configuration, when the temperature measured by the temperature sensor exceeds a preset value in a situation where the engine is operating, the valve switching means sets the switching valve to the supply position. In this situation, when it is determined that the temperature of the hydraulic oil measured by the temperature sensor has exceeded a preset value, the heat dissipation control means supplies the hydraulic oil from the electric hydraulic pump to the oil cooler and operates. Oil can be cooled. In other words, when the engine is operating, the hydraulic oil from the mechanical hydraulic pump driven by the engine is supplied to the transmission mechanism, so the electric hydraulic pump needs to supply the hydraulic oil to the transmission mechanism. Absent. On the other hand, when the rise of the hydraulic oil is measured by the temperature sensor, the electric hydraulic pump is operated to supply the hydraulic oil from the electric hydraulic pump directly to the oil cooler via the switching valve for efficient cooling. Is realized. As a result, a hydraulic pressure supply device that rationally realizes cooling of hydraulic oil is configured by utilizing a configuration having a mechanical hydraulic pump driven by an engine and an electric hydraulic pump driven by an electric motor. According to this configuration, when the mechanical hydraulic pump is stopped, the spool of the switching valve is in the cutoff position by the biasing force of the spring. For this reason, when the electric hydraulic pump is operated, the hydraulic oil from the electric hydraulic pump can be supplied to the transmission mechanism. In addition, when the mechanical hydraulic pump is operated and hydraulic oil is supplied from the mechanical hydraulic pump, the pressure of the hydraulic oil from the mechanical hydraulic pump acts on the switching valve via the operation oil passage. The spool operates to the supply position. For this reason, the hydraulic oil from the electric hydraulic pump can be supplied from the switching valve to the oil cooler to cool the hydraulic oil.

The present invention includes a merging oil passage that joins hydraulic oil sent from the electric hydraulic pump with hydraulic oil sent from the mechanical hydraulic pump , and the electric hydraulic pump is connected to the merging oil passage from the mechanical hydraulic pump to the electric hydraulic pump. A check valve for preventing the hydraulic oil from flowing to the hydraulic oil pump. One end of the operation oil passage is connected to the mechanical hydraulic pump side with reference to the check valve, and the check valve is used as a reference for electric operation. You may provide the cutoff oil path which makes this spool act | operate to the said interruption | blocking position by making the hydraulic oil from the hydraulic pump side act on the said spool .

According to this configuration, when the mechanical hydraulic pump is operated, the check valve prevents inconvenience that the hydraulic oil from the mechanical hydraulic pump is sent to the electric hydraulic pump. Further, when only the mechanical hydraulic pump operates, the pressure on the mechanical hydraulic pump side from the check valve becomes higher with reference to the pressure on the electric hydraulic pump side from the check valve in the combined oil passage. For this reason, the spool is operated to the supply position by the pressure from the operation oil passage, and the supply of the hydraulic oil from the electric hydraulic pump to the oil cooler is realized. Further, when only the electric hydraulic pump is operated, the pressure of the operation oil passage and the cutoff oil passage is equal, but the spool is operated to the cutoff position by the biasing force of the spring. Is supplied to the speed change mechanism.

The present invention may include a regulator valve that supplies hydraulic oil from the control oil passage to the transmission mechanism, and may include a surplus oil passage that supplies surplus oil from the regulator valve to the oil cooler .

With this configuration, surplus oil generated when hydraulic oil from the mechanical hydraulic pump is supplied from the regulator valve to the speed change mechanism is supplied from the surplus oil passage to the oil cooler, so that the hydraulic oil can be operated even when the electric hydraulic pump is not operated. Can be cooled.

The present invention includes a transmission system that transmits power from an engine to a travel drive system via a hydraulic transmission mechanism, a mechanical hydraulic pump that is driven by the power of the engine, and an electric hydraulic pump that is driven by an electric motor, A control oil passage for supplying hydraulic oil from one of the mechanical hydraulic pump and the electric hydraulic pump to the transmission mechanism, and maintaining the supply of hydraulic oil to the transmission mechanism by driving the electric hydraulic pump when the engine is stopped. And a control unit that
A heat dissipating oil passage for guiding the working oil sent from the electric hydraulic pump to an oil cooler is formed, and a supply position for supplying the working oil from the electric hydraulic pump to the heat dissipating oil passage and a shut-off position for shutting off the working oil. And a switching valve for setting the switching valve to the supply position in a situation where the engine is operated.
The switching valve is configured to include a spool that is operable between the supply position and the shut-off position, and the valve switching means is operated from a spring that biases the spool to the shut-off position and from the mechanical hydraulic pump. An operation oil passage that operates the spool in the direction of the supply position by causing oil to act against the biasing force of the spring may be provided.

With this configuration, when the engine is operating, hydraulic oil from a mechanical hydraulic pump driven by the engine is supplied to the transmission mechanism. By operating the electric hydraulic pump while the engine is operating in this way, the hydraulic oil is supplied from the electric hydraulic pump directly to the oil cooler via the switching valve to achieve cooling. Further, according to this configuration, when the mechanical hydraulic pump is stopped, the spool of the switching valve is in the cutoff position by the biasing force of the spring. For this reason, when the electric hydraulic pump is operated, the hydraulic oil from the electric hydraulic pump can be supplied to the transmission mechanism. In addition, when the mechanical hydraulic pump is operated and hydraulic oil is supplied from the mechanical hydraulic pump, the pressure of the hydraulic oil from the mechanical hydraulic pump acts on the switching valve via the operation oil passage. The spool operates to the supply position. For this reason, the hydraulic oil from the electric hydraulic pump can be supplied from the switching valve to the oil cooler to cool the hydraulic oil.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
〔overall structure〕
As shown in FIG. 1, the power from the engine 1 is transmitted from the main clutch 2 to the motor / generator 3 (indicated by M / G in the figure), and the power from the motor / generator 3 is transmitted to the torque converter 4 (same as the above). In the figure, a hybrid type travel drive system is configured which is shifted by the transmission mechanism 5 (shown as T / C) and further transmitted from the differential gear 6 to the left and right wheels 7. This travel drive system is provided in vehicles such as passenger cars and trucks.

  The engine 1 is composed of an internal combustion engine that is operated by fuel supplied from a fuel tank 8. The motor / generator 3 has a function of an electric motor that transmits the driving force to the torque converter by supplying the electric power from the battery 9 via the electric power control unit 10, the driving force from the engine 1, and at the time of braking 1 has a function of a generator for generating electric power from the driving force from the wheels 7, and the electric power generated in this way is sent from the electric power control unit 10 to the battery 9 and charged.

  The torque converter 4 has a function of transmitting a rotational driving force from the engine 1 to the speed change mechanism 5 through a fluid filled therein. The transmission mechanism 5 includes a plurality of transmission means that can be switched between a power transmission state and a power cut-off state by operation of a built-in friction multi-plate hydraulic clutch (not shown), and a gear shift that is linked to the plurality of transmission means. Provide gears. By setting any one of the transmission means to the power transmission state, it functions to transmit the power shifted at the gear ratio of the transmission gear linked to the transmission means to the traveling drive system.

  A regulator valve 11 for controlling the speed change of the speed change mechanism 5 is provided, and the regulator valve 11 is a plurality of electromagnetic valves that supply hydraulic oil to selected ones of a plurality of hydraulic clutches built in the speed change mechanism 5 ( (Not shown). A hydraulic system that supplies hydraulic oil to the regulator valve 11 from a mechanical hydraulic pump P1 driven by the engine 1 and an electric hydraulic pump P2 driven by the electric motor 12 is configured. The hydraulic pressure supply device of the invention is configured (details of this hydraulic pressure supply device will be described later). The electric motor 12 is a sensorless / brushless DC motor, and the electric motor 12 and the electric hydraulic pump P2 are provided so as to be immersed in an oil pan 5A of the transmission mechanism 5.

  As shown in FIG. 1, an ECU (Electric Control Unit) 13 is provided as a control unit for controlling the engine 1, the motor / generator 3, the power control unit 10, the regulator valve 11, the electric motor 12 of the electric hydraulic pump P2, and the like. .

  In this hybrid type traveling drive system, when the engine 1 is stopped by the control of the ECU 13, the driving force from the motor / generator 3 is transmitted to the traveling system to start the vehicle, and when the vehicle is started and then accelerated. The ECU 13 sets the gear stage of the transmission mechanism 5 appropriately under the control of the ECU 13, and starts the engine 1 under the control of the ECU 13 when shifting to high speed, and only the driving force from the motor / generator 3 is set. Instead, the driving force from the engine 1 is also transmitted to the traveling drive system to travel. Further, when the engine 1 is stopped, the electric hydraulic pump P2 is driven by the control of the ECU 13, and the supply of hydraulic oil to the regulator valve 11 and the transmission mechanism 5 is maintained.

  In particular, the ECU 13 obtains the measured value of the temperature sensor S that measures the temperature of the hydraulic oil supplied to the regulator valve 11, and uses the heat dissipation control means 13A that controls the electric hydraulic pump P2 based on the measured value. I have. The heat radiation control means 13A is configured by software (program), but may be configured by hardware combining a comparator, a logic gate, and the like. The temperature sensor S is disposed at a position for measuring the oil temperature of the hydraulic oil stored in the oil pan 5 </ b> A of the transmission mechanism 5.

[Hydraulic supply device]
The hydraulic pressure supply device includes the electric hydraulic pump P2 for supplying hydraulic oil to the hydraulic clutch of the speed change mechanism 5 to realize a speed change operation even when the engine 1 is stopped.

  Specifically, as shown in FIG. 2, a supply oil passage L1 that supplies hydraulic oil from the mechanical hydraulic pump P1 to the regulator valve 11 and a hydraulic oil from the electric hydraulic pump P2 to the first oil passage L. And a joining oil passage L2 to be joined, and a check valve 21 is provided for the joining oil passage L2, so that hydraulic oil from the mechanical hydraulic pump P1 is not supplied to the electric hydraulic pump P2 side. Yes. The supply oil passage L1 and the merging oil passage L2 constitute a control oil passage.

  In this hydraulic pressure supply device, the mechanical hydraulic pump P1 and the electric hydraulic pump P2 are configured such that the hydraulic oil stored in the oil pan 5A provided at the bottom of the transmission mechanism 5 is sucked and sent out, and the regulator valve 11 is formed with a lubricating oil passage L3 for supplying a part of the supplied hydraulic oil to the transmission mechanism 5 as lubricating oil.

  Further, a radiating oil passage L4 for supplying hydraulic oil from the electric hydraulic pump P2 to the oil cooler 22 is provided, and a switching valve V is provided in the middle of the radiating oil passage L4. Furthermore, a surplus oil passage L5 for joining surplus oil of the regulator valve 11 to the radiating oil passage L4 is formed, and a check valve 23 is interposed on the downstream side of the switching valve V in the radiating oil passage L4, A check valve 24 is also interposed in the middle of the surplus oil passage L5. Although the oil cooler 22 is structurally simplified to be provided on the side surface of the transmission mechanism 5, it is arranged in a position parallel to a radiator (not shown) for cooling the engine 1 in order to increase cooling efficiency. Alternatively, a cooling fan may be provided to enhance the cooling effect.

  The switching valve V has a structure in which a spool 26 is slidably operated inside the cylinder portion 25. The spool 26 forms land portions 26A at both end positions in the axial direction, thereby forming pressure receiving surfaces having the same area as the both end portions, and distribution of hydraulic oil having a small diameter at the center in the axial direction. A portion 26B is formed. Further, one side of the spool 26 is provided with a compression coil type spring 26C for applying an urging force. An input port is formed at a portion where the heat radiating oil passage L4 on the electric hydraulic pump P2 side communicates with the cylinder portion 25. In the cylinder portion 25, an output port is formed at a position on the extension of the heat radiating oil passage L4. Yes.

  Further, an operating oil passage C1 is formed to apply the pressure of the hydraulic oil in the supply oil passage L1 to the end of the switching valve V on the side not provided with the spring 26C. A shutoff oil passage C2 is formed in which the pressure of the hydraulic oil in the merged oil passage L2 is applied to the end of the cylinder portion 25 on the side provided with the spring 26C. The operation oil passage C1 and the cutoff oil passage C2 constitute the valve switching means of the present invention.

  FIG. 2 shows a situation in which hydraulic oil is supplied to the regulator valve 11 only from the mechanical hydraulic pump P1, and in this situation, the spool 26 is spring-loaded by the pressure acting on the spool 26 from the operating oil passage C1. It operates to the supply position of the operating end (position shown in the figure) against the urging force of 26C. That is, the biasing force of the spring 26C is set to a value lower than the pressure acting on the pressure receiving surface of the spool 26 from the operating oil passage C1, and the check valve 21 is provided in the middle of the merged oil passage L2. In a situation where hydraulic oil is supplied only from the mechanical hydraulic pump P1, no pressure acts on the shutoff oil passage C2, but pressure acts only on the operation oil passage C1, and as a result, both ends of the spool 26 Therefore, a large differential pressure is generated, and the spool 26 is set at the supply position as shown in FIG.

  Thus, in the situation where the spool 26 is in the supply position, the input port and the output port are in a positional relationship communicating with the portion of the circulation portion 26B of the spool 26. Therefore, when the electric hydraulic pump P2 is driven, The hydraulic oil sent to the switching valve V is sent from the input port to the portion of the circulation portion 26B of the spool 26 and sent out from the output port. As a result, the hydraulic oil from the electric hydraulic pump P2 is directly supplied to the oil cooler 22. The hydraulic oil can be cooled by supplying to

  FIG. 3 shows a situation in which hydraulic oil is supplied only from the electric hydraulic pump P2. In this situation, the pressure acting on both ends of the spool 26 is equal, so the spool 26 is blocked by the biasing force of the spring 26C. Operates to the position (position shown in the figure). In other words, in a situation where hydraulic oil is supplied only from the electric hydraulic pump P2, the pressure in the oil passage on the regulator valve 11 side and the electric hydraulic pump P2 are set in the middle of the merging oil passage L2. The pressure in the side oil passage is equal. Therefore, the pressure acting on one of the spools 26 from the operating oil passage C1 is equal to the pressure acting on the other side of the spool 26 (the side provided with the spring 26C) from the shutoff oil passage C2, so that the biasing force of the spring 26C The spool 26 operates to the shut-off position. As a result, the spool 26 is set to the shut-off position as shown in FIG.

  Thus, in the situation where the spool 26 is in the shut-off position, the input port and the output port reach a state closed by the land portion 26A of the spool 26, so that the operation is sent from the electric hydraulic pump P2 to the radiating oil passage L4. The oil is prevented from flowing by the land portion 26 </ b> A, and all the hydraulic oil from the electric hydraulic pump P <b> 2 is supplied to the regulator valve 11.

[Control form]
This hydraulic pressure supply device is controlled by the ECU 13. In a vehicle equipped with a hybrid travel drive system, as described above, when traveling by transmitting the drive force from the motor / generator 3 and the drive force from the engine 1 to the travel drive system, the mechanical hydraulic pump P1 is used. The hydraulic oil from the engine 1 is supplied to the regulator valve 11, and in such a state where the driving force from the engine 1 is transmitted to the travel drive system and travels, the heat dissipation control routine (the heat dissipation control means 13A) shown in the flowchart of FIG. Control) is executed.

  That is, when it is determined that the engine 1 is operating, the measured value of the temperature sensor S is acquired, and when it is determined that the measured value of the temperature sensor S exceeds a preset value, electric Control is performed to drive the hydraulic pump P2 (maintain the drive state if it is already in the drive state) (steps # 01 to # 04). Further, when the engine 1 is not in an operating state and when the temperature measured by the temperature sensor S does not exceed the set value even in a state where the engine 1 is operating, the electric hydraulic pump P2 is stopped. Control (maintaining the stopped state if already stopped) is performed (step # 05).

  As described above, according to the present invention, when the control of the heat radiation control routine is executed, the spool 26 of the switching valve V is in the supply position as shown in FIG. When it is determined that the oil temperature has risen to a value exceeding the set temperature, the hydraulic oil from the electric hydraulic pump P2 is directly passed through the regulator valve 11 by operating the electric hydraulic pump P2. Without) supplying to the oil cooler 22 to achieve efficient cooling.

  Further, when the engine 1 is stopped, the electric hydraulic pump P2 is operated, and the spool 26 of the switching valve V is in the shut-off position, so that the total amount of hydraulic oil from the electric hydraulic pump P2 is reduced to the regulator. Supply to the valve 11 to display an appropriate shift state. Further, when the hydraulic oil is supplied to the regulator valve 11 in this way, the excess oil is supplied from the excess oil passage L5 to the oil cooler 22 to cool the hydraulic oil.

[Another embodiment]
The present invention can be configured as follows in addition to the above-described embodiment.

(A) In the hybrid type traveling drive system, the motor / generator 3 has the functions of an electric motor and a generator as described above. Instead, an electric motor that outputs a traveling driving force; The hydraulic pressure supply device of the present invention may be applied to a vehicle having a configuration independently including a generator for power generation. In particular, the hydraulic pressure supply device of the present invention is not applied only to a hybrid type traveling drive system, and when the engine is driven by the driving force of the engine and stops traveling, idling continues for a set time or longer. It can be applied to a vehicle having an idling stop function for stopping the engine.

(B) By using an electromagnetic solenoid as a valve switching means for operating the switching valve V, the switching valve V is configured as an electromagnetic operation type. Alternatively, an electric actuator that operates the spool 26 of the switching valve V may be provided.

(C) The temperature sensor S may be disposed at a position other than the oil pan 5A, for example, a position for measuring the temperature of the outer wall of the transmission mechanism 5. Further, since the temperature of the hydraulic oil is proportional to the temperature of the cooling water of the engine 1, the temperature of the cooling water of the engine 1 may be measured by the temperature sensor S.

Block diagram showing the vehicle drive system and hydraulic system Hydraulic circuit diagram of the state in which hydraulic oil from the electric hydraulic pump is guided to the oil cooler Hydraulic circuit diagram of the state in which hydraulic oil from the electric hydraulic pump is led to the regulator valve Flow chart of heat dissipation control routine

Explanation of symbols

1 Engine 5 Transmission mechanism 11 Regulator valve 12 Electric motor 13 Control unit (ECU)
13A Heat radiation control means 21 Check valve 22 Oil cooler 26 Spool 26C Spring C1 Operation oil path C2 Shut off oil path P1 Mechanical hydraulic pump P2 Electric hydraulic pump S Temperature sensor V Switching valve

Claims (4)

A transmission system for transmitting power from the engine to a travel drive system via a hydraulic transmission mechanism, a mechanical hydraulic pump driven by the engine power, an electric hydraulic pump driven by an electric motor, and the mechanical hydraulic pressure A control oil path for supplying hydraulic oil from one of a pump and an electric hydraulic pump to the transmission mechanism, and a control unit for driving the electric hydraulic pump to maintain the supply of hydraulic oil to the transmission mechanism when the engine is stopped. With
A heat dissipating oil passage for guiding the working oil sent from the electric hydraulic pump to an oil cooler is formed, and a supply position for supplying the working oil from the electric hydraulic pump to the heat dissipating oil passage and a shut-off position for shutting off the working oil. And a switching valve for setting the switching valve to the supply position in a situation where the engine is operated.
A temperature sensor for measuring the temperature of the hydraulic oil is provided, and when it is determined that the temperature measured by the temperature sensor exceeds a preset value, a heat dissipation control means for operating the electric hydraulic pump is provided ,
The switching valve is configured to include a spool that is operable between the supply position and the shut-off position, and the valve switching means is operated from a spring that biases the spool to the shut-off position and from the mechanical hydraulic pump. A hydraulic pressure supply device configured to include an operation oil passage that operates oil in a direction of the supply position by causing oil to act against the biasing force of the spring . A hydraulic oil path that joins the hydraulic oil delivered from the electric hydraulic pump with the hydraulic oil delivered from the mechanical hydraulic pump; and the hydraulic oil from the mechanical hydraulic pump to the electric hydraulic pump with respect to the combined oil path A check valve for preventing the flow of the oil, and connecting one end of the operation oil passage to the mechanical hydraulic pump side based on the check valve;
The check on the basis of the operating oil from the side of the electric hydraulic pump valve that to act on said spool, hydraulic pressure supply device according to claim 1, characterized in that includes a shut-off oil passage for operating the spool in the blocking position. 3. The hydraulic pressure supply according to claim 1, further comprising a regulator valve that supplies hydraulic oil from the control oil path to the transmission mechanism, and a surplus oil path that supplies surplus oil from the regulator valve to the oil cooler. apparatus. A transmission system for transmitting power from the engine to a travel drive system via a hydraulic transmission mechanism, a mechanical hydraulic pump driven by the engine power, an electric hydraulic pump driven by an electric motor, and the mechanical hydraulic pressure A control oil path for supplying hydraulic oil from one of a pump and an electric hydraulic pump to the transmission mechanism, and a control unit for driving the electric hydraulic pump to maintain the supply of hydraulic oil to the transmission mechanism when the engine is stopped. With
A heat dissipating oil passage for guiding the working oil sent from the electric hydraulic pump to an oil cooler is formed, and a supply position for supplying the working oil from the electric hydraulic pump to the heat dissipating oil passage and a shut-off position for shutting off the working oil. And a switching valve for setting the switching valve to the supply position in a situation where the engine is operated.
The switching valve is configured to include a spool that is operable between the supply position and the shut-off position, and the valve switching means is operated from a spring that biases the spool to the shut-off position and from the mechanical hydraulic pump. A hydraulic pressure supply device configured to include an operation oil passage that operates oil in a direction of the supply position by causing oil to act against the biasing force of the spring .

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