JP2003294120A - Hydraulic supply device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a second hydraulic pump 22 of an electric type compact by using a first hydraulic pump 21 of a mechanical drive type while traveling by a motor as well. <P>SOLUTION: The first hydraulic pump 21 of a mechanical drive type is connected to the drive wheel side of a clutch, and it is constantly driven when a vehicle travels even in traveling by a motor. A first hydraulic passage 63 including the first hydraulic pump 21 and a second hydraulic passage 64 including the second hydraulic pump 22 are selectively switched by a first and a second electromagnetic changing valve 61 and 62. When the second hydraulic pump 22 is actuated, the first hydraulic passage 63 is disconnected from a hydraulic supply system. In backward traveling as traveling by a motor, the first hydraulic pump 21 is rotated inversely, but since working fluid circulates through a circulation passage 67 provided with a check valve 68, loss caused by pump-driving is minimized. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle that stops an engine and travels by an electric motor in a predetermined driving state, and more particularly, to a hydraulic pressure supply for supplying a hydraulic pressure necessary for gear shifting operation of the transmission. Regarding the device.

[0002]

2. Description of the Related Art In a hybrid vehicle in which an engine is automatically stopped and restarted in accordance with a driving state of the vehicle, in order to always secure a hydraulic pressure required for a transmission,
Generally, in addition to a mechanically driven hydraulic pump driven by an engine, it is necessary to provide an electric hydraulic pump driven by an electric motor. In particular, when a belt type continuously variable transmission (CVT) is used as the transmission, a high hydraulic pressure is required to operate the piston that tightens the belt. Has become a major issue for practical application.

For example, in a hybrid vehicle using a belt type continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. 2001-200920, an engine is used rather than a clutch for transmitting and disconnecting driving force between the engine and the transmission. A mechanical drive type hydraulic pump is provided on the side of the engine, and is driven in a form interlocking with the rotation of the engine. Therefore, this mechanically driven hydraulic pump is driven only in one direction of rotation and never reverses. Further, when the engine is stopped and the vehicle is driven by the traveling motor, the clutch is disengaged, so that the hydraulic pump is also stopped when the engine is stopped. Therefore, an electric hydraulic pump is provided as the second hydraulic pump, and when the engine is stopped, the electric hydraulic pump supplies hydraulic pressure to the gear shift operating portion of the transmission.

[0004]

In the structure described in the above publication, the entire required hydraulic pressure is always supplied by the electric hydraulic pump when the engine is stopped. Therefore, a large electric hydraulic pump is required, and generally a large system using an inverter-type high-voltage AC motor will result.

On the other hand, the present applicant is considering disposing the mechanical hydraulic pump on the output shaft side of the clutch. In this case, even when the engine is stopped, the mechanical drive hydraulic pump is driven at the same time when traveling by the traveling motor, so that the load on the electric hydraulic pump is reduced and the electric hydraulic pump is reduced. However, on the other hand, when the vehicle travels backward, a new problem arises in that the mechanical drive hydraulic pump is driven in the reverse rotation direction.

The present invention provides a hydraulic supply system for a hybrid vehicle capable of pumping the desired hydraulic oil even when the vehicle is traveling backward, which is a problem when a mechanical hydraulic pump is arranged on the output shaft side of the clutch. With the goal.

[0007]

According to a first aspect of the present invention, an engine is connected to an input shaft of a clutch, and an input shaft of a transmission and a traveling motor are connected to an output shaft of the clutch. And a vehicle propulsion mechanism configured to transmit the driving force from the output shaft of the transmission to the drive wheels, and the output shaft of the clutch, which is connected to the hydraulic oil in the hydraulic oil reservoir of the transmission. A mechanically driven first hydraulic pump that pressure-feeds to a speed change operation portion of the transmission, and an electric second hydraulic pump that is provided in parallel with the first hydraulic pump;
It is premised on a hydraulic pressure supply device for a hybrid vehicle that is equipped with the above-mentioned and that travels backward by the reverse rotation of the traveling motor. Therefore, when the engine is driving the drive wheels via the clutch, the output of the engine drives the first hydraulic pump. Further, even when the engine is stopped and the vehicle is traveling in the forward direction by the traveling motor, the first hydraulic pump is mechanically driven similarly. When the vehicle is moving backward, the engine is stopped and the traveling motor is rotated in the reverse direction to move the vehicle backward. At this time, the first hydraulic pump rotates in reverse with the output shaft of the clutch.

In the present invention, the working oil sump and the first
And the first hydraulic pump and the speed change operating portion, respectively, and the first hydraulic pump is moved from the hydraulic supply system during reverse traveling in which the first hydraulic pump reversely rotates. A first valve mechanism and a second valve mechanism that are substantially separated from each other, and are provided so as to connect the suction port side and the discharge port side of the first hydraulic pump between the first and second valve mechanisms. And a third valve mechanism provided in the recirculation passage so as to prevent backflow from the discharge port side to the suction port side during normal rotation of the first hydraulic pump. The hydraulic oil is pumped from the hydraulic oil reservoir to the speed change operating portion by the second hydraulic pump during reverse running.

That is, during the backward traveling in which the first mechanically driven hydraulic pump is rotated in the reverse direction, the first hydraulic pump is substantially disconnected from the hydraulic pressure supply system from the hydraulic oil sump to the speed change operating portion. Then, when the pump action occurs in the opposite direction with the reverse rotation and the working oil is discharged from the original suction port, the working oil circulates through the return passage. That is, the hydraulic oil circulates in the closed circuit including the first hydraulic pump. Therefore, a large loss does not occur due to the first hydraulic pump during the backward traveling.

As the third valve mechanism provided in the return passage, a solenoid valve that closes the return passage when the first hydraulic pump rotates in the normal direction can be used. However, as in claim 2, the suction port side is provided. It is possible to configure the check valve that allows only the flow from the air to the discharge port side.

The first valve mechanism and the second valve mechanism are
For example, as described in claim 3, each can be configured by a flow passage switching valve that selectively switches between the flow passage on the first hydraulic pump side and the flow passage on the second hydraulic pump side. in this case,
As in claim 7, when the rotation speed of the first hydraulic pump is less than a predetermined value, the second hydraulic pump is driven and the first valve mechanism and the second valve mechanism are operated at the second hydraulic pressure. It is desirable to switch to the pump side. This allows
The switching of the flow path is completed before the switching to the reverse traveling is actually performed.

Alternatively, as in claim 4, each of the check valves may be configured to allow only a flow in the direction from the hydraulic oil reservoir toward the speed change operating portion. That is, the first
If there is a pressure difference in the opposite direction due to the reverse rotation of the hydraulic pump, the check valve is closed, so that the first hydraulic pump is substantially disconnected. In this case, it is preferable that the second hydraulic pump be driven when the rotation speed of the first hydraulic pump is less than a predetermined value.

With this configuration, in forward traveling, the hydraulic oil is pumped by the first hydraulic pump while the engine is stopped and the vehicle is traveling by the traveling motor. Then, when the vehicle speed decreases and the supply of hydraulic oil by the first hydraulic pump becomes insufficient, the second hydraulic pump is driven.

Further, when the number of rotations of the first hydraulic pump is less than a predetermined value, the sum of the hydraulic pressure generated by the first hydraulic pump and the hydraulic pressure generated by the second hydraulic pump. It is desirable to drive the second hydraulic pump such that the above is substantially constant.

It is also possible to use either the first valve mechanism or the second valve mechanism as the flow path switching valve and the other as the check valve.

[0016]

According to the hydraulic supply system for a hybrid vehicle of the present invention, even if the first mechanically driven hydraulic pump is reversely driven during reverse travel, the hydraulic oil circulates in the closed circuit formed of the return passage. , Does not cause a large loss. Therefore, by mechanically driving the first hydraulic pump on the output shaft side of the clutch, the hydraulic pressure can be supplied without relying on only the electric second hydraulic pump during forward traveling by the traveling motor with the engine stopped. Therefore, the ability or performance required for the second hydraulic pump can be reduced. Therefore, the second
The hydraulic pump can be downsized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the structure of a vehicle propulsion mechanism of a hybrid vehicle in which the hydraulic pressure supply device according to the present invention is used. This propulsion mechanism includes an engine 1 including, for example, a gasoline engine or a diesel engine, a belt type continuously variable transmission (hereinafter abbreviated as CVT) 2 for changing the rotation of the engine 1, the engine 1 and the C
Clutch 3 that transmits and disconnects driving force to and from VT2
And a traveling motor for traveling the vehicle even when the engine 1 is stopped, that is, a traveling motor generator 4,
It is roughly composed of. In addition, this embodiment further includes a power generation motor generator 5 that mainly performs power generation while the engine is running and performs cranking when the engine 1 is restarted.

The clutch 3 is, for example, a hydraulic multi-plate clutch, and its input shaft 3a is substantially directly connected to the crankshaft 1a of the engine 1. A rotor (not shown) of the power generation motor generator 5 is fixed to the input shaft 3a. In addition, the motor generator 5 for power generation and the motor generator 4 for traveling
Are AC motor generators, and are controlled on both the drive side and the power generation side by a known inverter circuit.

The CVT 2 includes a primary pulley 11 on the driving side, a secondary pulley 12 on the driven side, and a metal belt 13 wound around the secondary pulley 12, and the pulley width of the primary pulley 11 is equal to that of the primary pulley 11. It can be adjusted by a hydraulic mechanism (not shown), and the pulley width of the secondary pulley 12 changes accordingly, so that the gear can be continuously changed. The transmission input shaft 11a including the primary pulley 11 is substantially directly connected to the output shaft 3b of the clutch 3. At the same time, the rotary shaft 4a of the traveling motor generator 4 is connected to the transmission input shaft 11a. Incidentally, the rotary shaft 4a of the traveling motor generator 4 and the transmission input shaft 11a
A reduction gear mechanism (not shown) is generally provided between and. The transmission output shaft 12a including the secondary pulley 12 includes a final gear 14 including a final drive gear 15 and a final driven gear 16, for example.
, And a differential gear 17, and are connected to an axle shaft 18 to transmit power to drive wheels 19.

On the other hand, a mechanically driven first hydraulic pump 21 and an electrically driven second hydraulic pump 22 are provided as hydraulic pressure supply devices, and the CVT 2 is supplied from a hydraulic oil reservoir (not shown) of the CVT 2. The hydraulic fluid is being pumped to the speed change operation unit (not shown). The shift operating unit is configured to include, for example, a pressure regulating valve and a hydraulic control valve, and uses the hydraulic pressure supplied from the hydraulic pumps 21 and 22 to generate an arbitrary control hydraulic pressure,
The gear ratio of CVT2 is variably controlled. The first hydraulic pump 21 is connected to and driven by the output shaft 3b of the clutch 3, that is, the transmission input shaft 11a. The first hydraulic pump 21 is composed of an internal gear pump described later, and its drive shaft is directly connected to the clutch output shaft 3b and the transmission input shaft 11a. In other words, the clutch 3, the first hydraulic pump 21, and the primary pulley 11
Are arranged coaxially in series. The electric second hydraulic pump 22 has a built-in low-voltage direct-current motor that can be driven by a vehicle-mounted battery for an auxiliary machine, and an internal gear pump is also used for the pump section. There is. The second hydraulic pump 22 is, as described later, the first hydraulic pump 2 that is mechanically driven, for example, when the vehicle is stopped.
It is driven when the hydraulic pressure due to 1 becomes insufficient.

FIG. 2 is a block diagram showing an outline of the control system for the hybrid vehicle. As shown,
This control system includes an electric oil pump control unit 32 that controls the electric oil pump, that is, the second hydraulic pump 22,
An engine control unit 33 that performs various controls of the engine 1,
A motor generator control unit 34 that controls the traveling motor generator 4 and the power generation motor generator 5 via an inverter circuit, a clutch control unit 35 that controls the clutch 3 via a hydraulic control valve, a gear ratio of the CVT 2, and the like. And a CVT control unit 36 for controlling
The entire system is a hybrid system control unit 3
1 is controlled in an integrated manner. Furthermore, in the present embodiment, electromagnetic switching valves 61 and 62 for switching the flow paths, which will be described later, are used.
An oil passage solenoid valve control unit 37 for controlling the above is provided.

The control of the entire hybrid vehicle will be briefly described. For example, during steady running at a medium vehicle speed or higher, the engine 1 is in combustion operation and the clutch 3 is in operation.
Are connected and the vehicle travels by the driving force of the engine 1. At this time, the power-generating motor generator 5 generates power. When the vehicle decelerates from the running state,
The traveling motor generator 4 regenerates deceleration energy, that is, generates electric power, and the clutch 3 is disengaged before the vehicle is stopped, so that the engine 1 is stopped. Then, when the vehicle starts from the stopped state, the clutch 3 is kept in the disengaged state, and the traveling motor generator 4 is driven,
The vehicle starts moving. After that, when the vehicle speed becomes equal to or higher than a predetermined low vehicle speed, cranking is performed by the motor generator 5 for power generation and the engine 1 is restarted. When the engine 1 is restarted, the clutch 3 is gradually connected and the traveling motor generator 4 is controlled so that the engine 1
Shift to driving by.

On the other hand, in the structure of this embodiment, the vehicle propulsion mechanism does not include a forward / reverse switching mechanism, and the engine 1 can only travel forward.
Therefore, the backward traveling is realized by turning the clutch 3 in the disengaged state and reversing the traveling motor generator 4. In other words, it is not generally considered that the vehicle travels for a long time while traveling in reverse. Therefore, the engine 1 is stopped and the traveling motor generator 4 is used to move backward, so that the transmission mechanism is simplified.

Since the first hydraulic pump 21 driven mechanically is directly connected to the transmission input shaft 11a as described above,
Whether the vehicle is traveling, whether traveling by the engine 1 or the traveling motor generator 4,
Along with this, it is mechanically driven. That is, vehicle speed and CVT
It is driven at a pump speed determined by a gear ratio of 2. This is the same regardless of whether the vehicle travels forward or backward. However, the pump rotation direction is the reverse rotation direction when the vehicle travels in the reverse direction, whereas the pump rotation direction when the vehicle travels in the forward direction (this direction is defined as the normal rotation direction).

FIG. 3 shows a specific structure of the internal gear pump used for the first hydraulic pump 21 and the second hydraulic pump 22 described above. This internal gear pump is a known pump, and is housed in a cylindrical housing 41.
A ring-shaped internal gear 42 is rotatably fitted and held, and an external gear 43 is arranged at a position eccentric to one of the inner peripheral sides of the internal gear 42. The external gear 43 is rotationally driven by the clutch output shaft 3b and the motor rotary shaft, and has teeth 43a on the outer periphery thereof.
Meshes with the tooth groove 42a of the internal gear 42, and the internal gear 42 also rotates with the housing 4 as the external gear 43 rotates.
Rotate within 1. A suction port 44 and a discharge port 45 are formed on one of the end plates that close the axial end of the housing 41 so as to sandwich the external gear 43 in the radial direction. Further, a partition plate 46 having a substantially crescent shape is provided so as to fill a space between the external gear 43 and the internal gear 42, which is generated as a result of the external gear 43 being eccentric to one side, and an inner peripheral surface thereof is provided. The tip of the external gear 43 is in sliding contact with the tip of the internal gear 42 on the outer peripheral surface.

In such an internal gear pump,
By driving the external gear 43 in the normal direction as indicated by the arrow ω, the hydraulic oil is sucked from the suction port 44, pressurized, and discharged from the discharge port 45. And
This internal gear pump can be rotated in the opposite direction to the arrow ω. In this case, the discharge port 45
Hydraulic oil is sucked from the suction port 44 and is pressurized so that the suction port 44
Will be discharged from. Further, when the external gear 43 is not driven to rotate, the partition plate 46 closes the external gear 43 and the internal gear 42, so that the leakage of hydraulic oil between the ports 44 and 45 is extremely small. There are few.

Next, the first and second hydraulic pumps 21,
The hydraulic circuit provided with 22 will be described.

FIG. 4 shows a first embodiment of the hydraulic circuit. In particular, FIG. 4A shows the flow of hydraulic oil during forward traveling, and FIG. 4B shows the flow of hydraulic oil during backward traveling. , Are also shown together. In the figure, reference numeral 51 indicates a hydraulic oil reservoir of the CVT 2 from which hydraulic oil is collected from each portion, and 52 indicates a shift operating portion of the CVT 2 which is a hydraulic pressure supply destination. Further, the suction port 44 and the discharge port 4 of the first hydraulic pump 21.
5 as 44-1 and 45-1, respectively,
The suction port 44 and the discharge port 45 of the second hydraulic pump 22 are shown by symbols 44-2 and 45-2, respectively. The names "suction port" and "discharge port" are based on the forward rotation of each pump as described above, and the suction port 4 is rotated at the reverse rotation.
4 is on the discharge side, and the discharge port 45 is on the suction side.

As shown in the figure, the first embodiment is provided with a first electromagnetic switching valve 61 serving as a first valve mechanism and a second electromagnetic switching valve 62 serving as a second valve mechanism. First above
The electromagnetic switching valve 61 includes a first port 61a and a second port 61a.
It is a 3-port 2-position switching valve that selectively communicates with either b or the third port 61c, and the first port 61a is connected to the hydraulic oil sump 51. Similarly,
The second electromagnetic switching valve 62 is a three-port two-position switching valve that selectively communicates the first port 62a with either the second port 62b or the third port 62c, and the first port 62a is a gear shift operation. It is connected to the section 52. A first hydraulic passage 63 is connected between the second port 61b of the first electromagnetic switching valve 61 and the second port 62b of the second electromagnetic switching valve 62, and the first hydraulic passage 63 has the first hydraulic pressure. A pump 21 is arranged. In addition, the first electromagnetic switching valve 6
A second hydraulic passage 64 is connected between the first third port 61c and the third port 62c of the second electromagnetic switching valve 62, and the second hydraulic pump 22 is arranged in the second hydraulic passage 64. . Further, between the connection point 65 on the suction side of the first hydraulic pump 21 and the connection point 66 on the discharge side of the first hydraulic passage 63, the return passage 6 is arranged in parallel with the first hydraulic pump 21.
7 is connected. A check valve 68, which allows only a flow in the direction from the connection point 65 to the connection point 66, is interposed in the return passage 67 as a third valve mechanism.

The first electromagnetic switching valve 61 and the second electromagnetic switching valve 62 are switching-controlled by the oil passage electromagnetic valve control section 37 in the above-mentioned control system, but basically, the second hydraulic hydraulic pump 22 of the electric type. The flow paths are switched in a manner linked to the on / off of.

That is, during forward traveling in which the first hydraulic pump 21 is driven in the normal direction, both the first and second electromagnetic switching valves 61 and 62 are turned on as shown by the arrows in FIG. It is switched to the second port 61b, 62b side,
The hydraulic oil is pressure-fed from the hydraulic oil sump 51 to the shift operating portion 52 by the first hydraulic pump 21 through the first hydraulic passage 63. At this time, the check valve 68 is closed, and the return passage 67 is
Backflow of hydraulic oil through the oil is prevented. Further, the second hydraulic pump 22 is stopped.

On the other hand, when the first hydraulic pump 21 is driven in reverse, the first and second electromagnetic switching valves 61 and 62 are both operated as indicated by arrows in FIG. Is switched to the third port 61c, 62c side, and at the same time, the second hydraulic pump 22 is turned on.
The hydraulic oil is pumped from the hydraulic oil sump 51 to the shift operating portion 52 by the second hydraulic pump 22 through the second hydraulic passage 64. The first hydraulic passage 63 including the first hydraulic pump 21 is completely disconnected from the hydraulic pressure supply system that extends from the hydraulic oil sump 51 to the gear shift operating portion 52. here,
By the reverse rotation of the first hydraulic pump 21, the suction port 44-
Since the pressure of 1 is relatively higher than that of the discharge port 45-1, the hydraulic oil circulates through the return passage 67. By circulating the hydraulic oil in the closed circuit in this way, the energy consumed by the first hydraulic pump 21 is minimized.

FIG. 5 is an explanatory diagram for explaining the operation of the first and second hydraulic pumps 21 and 22 and changes in hydraulic pressure when the vehicle shifts from forward traveling to backward traveling. Specifically, the driver decelerates and stops the vehicle while traveling forward, and the transmission (C
The figure shows a state in which the shift lever of VT2) is switched from the drive range for forward travel (D range) to the reverse range for reverse travel (R range) and then reverse travel is started.

As shown, the first hydraulic pump 21 is
Although the vehicle is driven in the forward rotation direction during forward traveling, the rotational speed decreases as the vehicle speed decreases, and the generated hydraulic pressure also decreases accordingly. The operation of the second hydraulic pump 22 starts when this hydraulic pressure drops to the minimum required hydraulic pressure. At the same time, the first and second electromagnetic switching valves 61 and 62 are switched to the second hydraulic passage 64 side. As a result, the gear shift operating unit 52
The hydraulic pressure of the hydraulic oil sent to is ensured to be higher than the minimum required hydraulic pressure. Actually, it is possible to start the operation of the second hydraulic pump 22 when the rotational speed of the first hydraulic pump 21 falls below a predetermined rotational speed without detecting the hydraulic pressure. After that, the hydraulic pressure is not supplied from the first hydraulic pump 21 while the vehicle is stopped and when the vehicle is moving backward.
Only 2 gives the required oil pressure. It should be noted that although the hydraulic pressure drops momentarily due to the switching of the first and second electromagnetic switching valves 61 and 62, there is no problem because it is for a very short period of time and deceleration is in progress before the actual reverse movement is started. . After that, when the reverse drive is started by driving the traveling motor generator 4, the first hydraulic pump 21 is also driven in the reverse rotation direction, so that the hydraulic oil circulates in the return passage 67 as described above.

Next, FIG. 6 shows a second embodiment of the hydraulic circuit. FIG. 6A shows the flow of hydraulic oil during forward traveling, and FIG. 6B shows the flow of hydraulic oil during backward traveling. Are also shown together. The parts substantially equivalent to those in the first embodiment of FIG. 4 are designated by the same reference numerals. Also in the hydraulic circuit of the second embodiment, the first hydraulic passage 63 having the first hydraulic pump 21 and the second hydraulic passage 64 having the second hydraulic pump 22 are provided in parallel. First and second
The hydraulic passages 63 and 64 are respectively connected between the hydraulic oil sump 51 and the speed change operating portion 52. In the illustrated example, the passages 63 and 64 merge into one at the upstream connection point 71 and the downstream connection point 72. And
In this embodiment, a first check valve 73 and a second check valve 74 are used as the first valve mechanism and the second valve mechanism, respectively. The first check valve 73 is located on the upstream side of the connection point 65 to which the return passage 67 is connected, and the hydraulic oil sump 5
It is arranged in a direction in which only the flow from 1 to the connection point 65 is allowed. The second check valve 74 is located on the downstream side of the connection point 66 to which the return passage 67 is connected, and is arranged in a direction that allows only the flow from the connection point 66 to the speed change operation portion 52.

Therefore, when traveling forward, the first hydraulic pump 21
Is driven to rotate normally, as shown by the arrow in FIG. 5A, the flow of hydraulic oil passes through the first check valve 73 and the second check valve 74 from the hydraulic oil sump 51 to the speed change operating portion 52. And hydraulic fluid is pumped. Here, the backflow through the return passage 67 is also blocked by the check valve 68. Second hydraulic pump 2
2 is always connected between the hydraulic oil sump 51 and the speed change operating portion 52, and when the hydraulic pressure is insufficient, it is driven by it.
The hydraulic oil can be pressure-fed from the hydraulic oil sump 51 to the speed change operating portion 52.

It should be noted that the second hydraulic pump 22, which is an internal gear pump, has little leakage at the time of stop, and therefore, when the first hydraulic pump 21 is operating, hydraulic oil is passed from the connecting point 72 to the connecting point 71 through the second hydraulic pump 22. However, if necessary, a check valve may be arranged in series with the second hydraulic pump 22 to completely prevent the reverse flow through the second hydraulic pump 22. it can.

When traveling backward, the second hydraulic pump 22 is driven to move from the hydraulic oil sump 51 to the shift operating portion 5 as shown by the arrow in FIG.
The hydraulic oil is pumped to 2. Then, the first hydraulic pump 2
When 1 reverses, the suction port 44-1 of the first hydraulic pump 21 becomes high pressure and the discharge port 45-1 becomes low pressure, which causes the first check valve 73 and the second check valve 74 to move. Closed, the first hydraulic pump 21 is substantially disconnected from the hydraulic supply system. In this state, the working oil circulates in the return passage 67 as in the first embodiment described above.

FIG. 7 is an explanatory view for explaining the operation and hydraulic pressure changes of the first and second hydraulic pumps 21, 22 when the vehicle shifts from forward traveling to backward traveling in the second embodiment. Specifically, the driver decelerates and stops the vehicle during forward traveling, switches the shift lever of the transmission (CVT2) from the D range for forward traveling to the R range for backward traveling, and then starts reverse. It shows how to do it.

As described above, the first hydraulic pump 21
Although the vehicle is driven in the forward rotation direction during forward traveling, the rotational speed decreases as the vehicle speed decreases, and the generated hydraulic pressure also decreases accordingly. Then, when the hydraulic pressure drops to the minimum required hydraulic pressure (or when the pump rotation speed becomes less than the predetermined rotation speed), the operation of the second hydraulic pump 22 is started.
As a result, the hydraulic pressure of the hydraulic oil pressure-fed to the speed change operating unit 52 is ensured to be equal to or higher than the minimum required hydraulic pressure. While the vehicle is stopped,
The first hydraulic pump 21 does not generate hydraulic pressure, and only the second hydraulic pump 22 provides necessary hydraulic pressure. Then, even after the reverse drive is started, the hydraulic pressure is not supplied from the first hydraulic pump 21, and the hydraulic pressure is continuously supplied by the second hydraulic pump 22. In this embodiment, since the flow passage is not switched when the operation of the second hydraulic pump 22 is started, the hydraulic pressure does not drop instantaneously as in the first embodiment. Further, in forward traveling, the hydraulic pressure generated by the first hydraulic pump 21 is used even when traveling by driving the traveling motor generator 4, which is even more advantageous in downsizing the second hydraulic pump 22.

The second hydraulic pump 22 is simply turned on.
Although it may be operated off, it is also possible to control the number of revolutions thereof so that the combined hydraulic pressure of the first hydraulic pump 21 maintains a constant value.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a vehicle propulsion mechanism of a hybrid vehicle according to the present invention.

FIG. 2 is a block diagram showing an outline of a control system for this hybrid vehicle.

FIG. 3 is an explanatory diagram showing a configuration of an internal gear pump.

FIG. 4 is a circuit diagram showing a first embodiment of a hydraulic circuit.

FIG. 5 is an explanatory view showing a change in hydraulic pressure when shifting from forward traveling to reverse traveling in the first embodiment.

FIG. 6 is a circuit diagram showing a second embodiment of the hydraulic circuit.

FIG. 7 is an explanatory diagram showing a change in hydraulic pressure when shifting from forward traveling to reverse traveling in the second embodiment.

[Explanation of symbols]

1 ... engine 2 ... CVT 3 ... Clutch 4. Motor generator for traveling 21 ... 1st hydraulic pump 22 ... Second hydraulic pump 51 ... hydraulic oil reservoir 52 ... Gear shift operation unit 61 ... First electromagnetic switching valve 62 ... Second solenoid switching valve 67 ... Return path 68 ... Check valve 73 ... First check valve 74 ... Second check valve

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Claims (7)

[Claims] 1. An engine is connected to an input shaft of a clutch, an input shaft of a transmission and a traveling motor are connected to an output shaft of the clutch, and a driving force is applied from the output shaft of the transmission to driving wheels. A vehicle-driven propulsion mechanism configured to be transmitted, and a first mechanical drive type that is connected to an output shaft of the clutch and pressure-feeds hydraulic fluid in a hydraulic fluid reservoir of the transmission to a shift operating portion of the transmission. Hydraulic pump and an electrically driven second pump provided in parallel with the first hydraulic pump.
A hydraulic vehicle, comprising: the hydraulic pump according to claim 1, wherein the vehicle travels in reverse by the reverse rotation of the traveling motor, between the hydraulic oil reservoir and the first hydraulic pump, and between the first hydraulic pump and the speed change operating unit. A first valve mechanism and a second valve mechanism, which are respectively provided between the first hydraulic pump and the first hydraulic pump and which substantially separates the first hydraulic pump from the hydraulic supply system during reverse traveling in reverse rotation; A return passage provided so as to connect the suction port side and the discharge port side of the first hydraulic pump between the first and second valve mechanisms, and the discharge port at the time of normal rotation of the first hydraulic pump. A third valve mechanism provided in the recirculation passage so as to prevent backflow from the intake side to the suction port side, and when the vehicle travels in reverse, the second hydraulic pump causes the change from the hydraulic oil sump to the above-mentioned change. A hydraulic pressure supply device for a hybrid vehicle, characterized in that hydraulic oil is pressure-fed to a fast operating part. 2. The hybrid vehicle according to claim 1, wherein the third valve mechanism is composed of a check valve that allows only the flow from the suction port side to the discharge port side. Hydraulic supply device. 3. The first valve mechanism and the second valve mechanism each include a flow passage switching valve that selectively switches between a flow passage on the first hydraulic pump side and a flow passage on the second hydraulic pump side. The hydraulic pressure supply device for a hybrid vehicle according to claim 1 or 2, which is configured. 4. The first valve mechanism and the second valve mechanism are each formed of a check valve that allows only a flow in a direction from a working oil sump to a speed change operating portion. The hydraulic pressure supply device for a hybrid vehicle according to claim 1. 5. The hydraulic supply system for a hybrid vehicle according to claim 4, wherein the second hydraulic pump is driven when the rotation speed of the first hydraulic pump is less than a predetermined value. 6. The hydraulic pressure generated by the first hydraulic pump and the second hydraulic pump when the rotational speed of the first hydraulic pump is less than a predetermined value.
The hydraulic pressure supply device for a hybrid vehicle according to claim 5, wherein the second hydraulic pump is driven so that the sum of the generated hydraulic pressure of the hydraulic pump and the generated hydraulic pressure is substantially constant. 7. The second hydraulic pump is driven when the rotation speed of the first hydraulic pump is less than a predetermined value, and the first valve mechanism and the second valve mechanism are on the second hydraulic pump side. 4. The hydraulic pressure supply device for a hybrid vehicle according to claim 3, wherein the hydraulic pressure supply device is switched to.