JP6760766B2 - Control device for continuously variable transmission - Google Patents

Description

The present invention relates to a control device for a continuously variable transmission.

In recent years, continuously variable transmissions (CVTs) such as chain type and belt type that can change the gear ratio steplessly have been widely put into practical use as automatic transmissions for vehicles. In general, such a continuously variable transmission is provided with a forward / backward switching mechanism for switching between forward rotation and reverse rotation of the drive wheels (that is, forward and reverse movement of the vehicle) (see, for example, Patent Document 1).

The reverse switching mechanism described in Patent Document 1 is mainly configured to include a double pinion type planetary gear train, a forward clutch, and a reverse clutch (reverse brake). The forward clutch is, for example, a multi-plate clutch, and is engaged by supplying clutch pressure. Similarly, the reverse clutch is a multi-plate clutch, and is engaged by supplying clutch pressure. Then, when the forward clutch is engaged and the reverse clutch is released, the engine rotation is directly transmitted to the primary pulley to enter the forward state. On the other hand, when the forward clutch is released and the reverse clutch is engaged, the rotation of the engine is reversed by the planetary gear train and the reverse clutch is transmitted to the primary pulley.

Japanese Unexamined Patent Publication No. 2013-24327

By the way, when the select lever is operated from neutral (N) or parking (P) to drive (D) or reverse (R) and the forward clutch or reverse clutch is engaged, that is, in the clutch chamber of the forward clutch or reverse clutch. When the oil is filled, a drop in line pressure occurs. When such a decrease in line pressure occurs, the lateral pressure (for example, secondary pressure) of the variator holding the chain constituting the continuously variable transmission decreases, and chain slip may occur.

Therefore, conventionally, the hydraulic pressure of the oil to be filled in the clutch chamber has been controlled so as not to cause a decrease in line pressure that causes chain slip. That is, the clutch chamber was filled (supplied) with oil relatively gently. Therefore, there is a possibility that the engagement delay (time lag) of the forward clutch or the reverse clutch may occur at the time of starting (forward side or reverse side).

The present invention has been made to solve the above-mentioned problems, and when engaging the clutch (forward clutch or reverse clutch) constituting the forward / backward switching mechanism, the clutch is prevented from dropping in line pressure. An object of the present invention is to provide a control device for a continuously variable transmission capable of shortening a fastening delay.

The stepless transmission control device according to the present invention is provided between the engine and the drive wheels and switches between forward rotation and reverse rotation of the drive wheels and a selection means that accepts an operation of selecting the range of the stepless transmission. A forward / backward switching mechanism, an oil pump having a first discharge port and a second discharge port for discharging boosted oil, a main hydraulic circuit communicated with the first discharge port, and oil discharged from the second discharge port. A first switching valve that switches the discharge destination between the main hydraulic circuit and the sub-hydraulic circuit that communicates with the clutch that constitutes the forward / backward switching mechanism, and the sub-hydraulic circuit that opens and closes the sub-hydraulic circuit. 2 It is interposed on the downstream side of the branch between the main hydraulic circuit and the hydraulic circuit that supplies oil to the main hydraulic circuit and the variator, and on the upstream side of the clutch that constitutes the forward / backward switching mechanism, and opens and closes the main hydraulic circuit. When a third switching valve and a control means for controlling the drive of the first switching valve, the second switching valve, and the third switching valve are provided, and the parking range or the neutral range is selected by the selection means. In addition, the first switching valve is driven to switch the discharge destination of the oil discharged from the second discharge port to the sub-hydraulic circuit side, the second switching valve is opened, and the third switching valve is closed to select. When the range is switched from the parking range or the neutral range to the drive range or the reverse range by means and the clutch constituting the forward / backward switching mechanism is engaged, the first switching is performed based on the operating state of the stepless transmission. It is characterized in that the valve is driven to switch the discharge destination of the oil discharged from the second discharge port, the second switching valve is closed, and the third switching valve is opened.

According to the control device for the stepless transmission according to the present invention, the discharge destination of the oil discharged from the second discharge port is between the main hydraulic circuit and the sub hydraulic circuit that communicates with the clutch constituting the advance switching mechanism. A first switching valve that is switched by, a second switching valve that is interposed in the sub-hydraulic circuit and opens and closes the sub-hydraulic circuit, and a hydraulic circuit that supplies oil to the main hydraulic circuit and the variator (primary pulley and secondary pulley). It is provided with a third switching valve that is interposed on the downstream side of the branch portion and on the upstream side of the clutch constituting the advance switching mechanism to open and close the main hydraulic circuit. Then, when the parking (P) range or the neutral (N) range is selected by the selection means, the first switching valve is driven and the discharge destination of the oil discharged from the second discharge port is switched to the sub-hydraulic circuit side. The second switching valve is opened and the third switching valve is closed. Further, when the range is switched from the parking (P) range or the neutral (N) range to the drive (D) range or the reverse (R) range by the select means, and the clutch constituting the forward / backward switching mechanism is engaged. In addition, the first switching valve is driven based on the operating state of the continuously variable transmission to switch the discharge destination of the oil discharged from the second discharge port, the second switching valve is closed, and the third switching valve is closed. Is opened.

Therefore, by controlling the first switching valve, the second switching valve, and the third switching valve, the main hydraulic circuit and the sub hydraulic circuit can be made independent for each discharge port of the oil pump, and the main hydraulic circuit It is possible to supply oil from the sub-hydraulic circuit to the forward / backward switching mechanism (clutch) in a state where the communication between the vehicle and the forward / backward switching mechanism (clutch) is cut off. That is, when oil is supplied to the forward / backward switching mechanism (clutch), the line pressure can be prevented from dropping (dropping) by cutting off the communication between the main hydraulic circuit and the forward / backward switching mechanism (clutch). In addition, by supplying oil from the sub-hydraulic circuit to the forward / backward switching mechanism (clutch) without being affected by the decrease in line pressure, the clutch (forward clutch or reverse clutch) is engaged (initial engagement) faster. It can be performed. As a result, when engaging the clutch (forward clutch or reverse clutch) constituting the forward / backward switching mechanism, it is possible to shorten the clutch engagement delay while preventing a decrease in line pressure.

In the continuously variable transmission control device according to the present invention, the control means closes the second switching valve when the clutch is engaged and the hydraulic pressure of the main hydraulic circuit becomes higher than the hydraulic pressure of the sub hydraulic circuit. It is preferable to open the third switching valve.

In this way, backflow from the sub-hydraulic circuit to the main hydraulic circuit (that is, backflow from the clutch pressure side to the line pressure side) can be prevented. Therefore, it is possible to prevent a decrease in the clutch engaging force that may occur when a backflow occurs.

In the control device for the continuously variable transmission according to the present invention, the control means drives the first switching valve when the parking range or the neutral range is selected by the select means and the engine speed is equal to or less than the predetermined speed. It is preferable that the discharge destination of the oil discharged from the second discharge port is switched to the sub-hydraulic circuit side, the second switching valve is opened, and the third switching valve is closed.

By doing so, only at the time of starting (forward side or reverse side) when the engine speed is relatively low (that is, the discharge amount of the oil pump is relatively small and the line pressure tends to decrease), the front and rear from the sub-hydraulic circuit Oil can be supplied to the clutch constituting the advance switching mechanism (the clutch chamber is filled with oil).

In the continuously variable transmission control device according to the present invention, the first switching valve is used when the control means is selected from the parking range or the neutral range by the select means and the oil temperature of the continuously variable transmission is equal to or higher than a predetermined temperature. It is preferable that the discharge destination of the oil discharged from the second discharge port is switched to the sub-hydraulic circuit side, the second switching valve is opened, and the third switching valve is closed.

By doing so, the sub is limited to the situation where the oil temperature rises, the viscosity of the oil decreases, and the amount of oil leakage (return amount) increases (that is, the line pressure tends to decrease). Oil can be supplied from the hydraulic circuit to the clutch constituting the forward / backward switching mechanism (the clutch chamber is filled with oil).

In the control device for the continuously variable transmission according to the present invention, when the second switching valve closes the sub-hydraulic circuit, the discharge destination of the oil discharged from the second discharge port is switched to the suction port of the oil pump. Is preferable.

In this way, the operating state of the oil pump can be switched between the full discharge operating state and the partial discharge (half discharge) operating state based on the operating state of the continuously variable transmission. Therefore, the load on the oil pump can be appropriately reduced.

The control device for the stepless transmission according to the present invention is interposed on the downstream side of the second switching valve of the sub hydraulic circuit, and when the hydraulic pressure of the sub hydraulic circuit is higher than the hydraulic pressure of the main hydraulic circuit, the sub hydraulic circuit An additional one-way valve that allows the inflow of oil into the main hydraulic circuit and prohibits the inflow of oil from the main hydraulic circuit into the sub-hydraulic circuit when the oil pressure in the sub-hydraulic circuit is lower than the hydraulic pressure in the main hydraulic circuit. Is preferable.

In this way, it is possible to prevent the backflow of oil from the main hydraulic circuit to the sub hydraulic circuit.

According to the present invention, when engaging a clutch (forward clutch or reverse clutch) constituting a forward / backward switching mechanism, it is possible to shorten the clutch engagement delay while preventing a decrease in line pressure.

It is a block diagram which shows the structure of the control device of the continuously variable transmission which concerns on embodiment, the continuously variable transmission to which the control device of the continuously variable transmission is applied, and the like. It is a figure which shows the hydraulic circuit configuration (only the main part) of the valve body of the continuously variable transmission which concerns on embodiment. It is a flowchart which shows the processing procedure of the clutch control of the forward / reverse movement switching mechanism by the control device of the continuously variable transmission which concerns on embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts. Further, in each figure, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

First, the configuration of the continuously variable transmission control device 1 according to the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a configuration of a continuously variable transmission control device 1 and a continuously variable transmission 20 to which the continuously variable transmission control device 1 is applied. FIG. 2 is a diagram showing a hydraulic circuit configuration (only a main part) of the valve body 50 of the oil pump 70 and the continuously variable transmission 20.

The engine 10 may be of any type, and is, for example, a horizontally opposed in-cylinder in-cylinder gasoline engine. In the engine 10, the air sucked from the air cleaner (not shown) is throttled by an electronically controlled throttle valve (hereinafter, simply referred to as “throttle valve”) 13 provided in the intake pipe, passes through the intake manifold, and reaches the engine 10. It is sucked into each formed cylinder. Here, the amount of air sucked from the air cleaner is detected by the air flow meter 61. Further, the throttle valve 13 is provided with a throttle opening sensor 14 for detecting the opening degree of the throttle valve 13. Each cylinder is equipped with an injector that injects fuel. Further, each cylinder is equipped with a spark plug that ignites the air-fuel mixture and a coil with a built-in igniter that applies a high voltage to the spark plug. In each cylinder of the engine 10, a mixture of intake air and fuel injected by an injector is ignited by a spark plug and burned. The exhaust gas after combustion is discharged through the exhaust pipe.

In addition to the air flow meter 61 and the throttle opening sensor 14 described above, a cam angle sensor for discriminating the cylinder of the engine 10 is attached in the vicinity of the camshaft of the engine 10. Further, a crank angle sensor for detecting the position of the crankshaft is attached in the vicinity of the crankshaft of the engine 10. These sensors are connected to an engine control unit (hereinafter referred to as "ECU") 60, which will be described later. Further, various sensors such as an accelerator pedal sensor 62 that detects the amount of depression of the accelerator pedal, that is, the opening degree of the accelerator pedal, and a water temperature sensor that detects the temperature of the cooling water of the engine 10 are also connected to the ECU 60.

The crankshaft (output shaft) 15 of the engine 10 is continuously output by converting the driving force from the engine 10 via a torque converter 21 having a clutch function and a torque amplification function and a forward / backward switching mechanism 27. The transmission 20 is connected.

The torque converter 21 is mainly composed of a pump impeller 22, a turbine liner 23, and a stator 24. The pump impeller 22 connected to the crankshaft (output shaft) 15 creates a flow of oil, and the turbine liner 23 arranged to face the pump impeller 22 receives the power of the engine 10 via the oil to drive the output shaft. To do. The stator 24 located between the two rectifies the discharge flow (return) from the turbine liner 23 and reduces it to the pump impeller 22 to generate a torque amplification action.

Further, the torque converter 21 has a lockup clutch 25 that directly connects the input and the output. When the lockup clutch 25 is not engaged (in the non-lockup state), the torque converter 21 amplifies the driving force of the engine 10 and transmits it to the continuously variable transmission 20, and the lockup clutch 25 is engaged. When it is (locked up), the driving force of the engine 10 is directly transmitted to the continuously variable transmission 20. The rotation speed (turbine rotation speed) of the turbine liner 23 constituting the torque converter 21 is detected by the turbine rotation speed sensor 56. The detected turbine speed is output to a transmission control unit (hereinafter referred to as "TCU") 40, which will be described later.

The forward / backward switching mechanism 27 switches between forward rotation and reverse rotation (forward and reverse of the vehicle) of the drive wheels. The forward / backward switching mechanism 27 mainly includes a double pinion type planetary gear train 28, a forward clutch 29, and a reverse clutch (reverse brake) 30. The forward / backward switching mechanism 27 is configured to be able to switch the transmission path of the engine driving force by controlling the states of the forward clutch 29 and the reverse clutch 30.

More specifically, by engaging the forward clutch 29 and releasing the reverse clutch 30, the rotation of the turbine shaft 26 is directly transmitted to the primary shaft 32, which will be described later, and the vehicle can be driven forward. Further, by releasing the forward clutch 29 and engaging the reverse clutch 30, the planetary gear train 28 can be operated to reverse the rotation direction of the primary shaft 32, and the vehicle can be driven backward. By releasing the forward clutch 29 and the reverse clutch 30, the turbine shaft 26 and the primary shaft 32 are separated from each other, and the forward / backward switching mechanism 27 is in a neutral state in which power is not transmitted to the primary shaft 32. The operation of the forward clutch 29 and the reverse clutch 30 is controlled by the TCU 40 and the valve body (control valve) 50, which will be described later. Further, hereinafter, when it is not necessary to distinguish between them, the forward clutch 29 and the reverse clutch 30 may be collectively referred to as the forward / backward clutches 29 and 30.

The continuously variable transmission 20 includes a primary shaft 32 connected to the turbine shaft (output shaft) 26 of the torque converter 21 via a forward / backward switching mechanism 27, and a secondary shaft 37 arranged in parallel with the primary shaft 32. have.

A primary pulley 34 is provided on the primary shaft 32. The primary pulley 34 has a fixed pulley 34a joined to the primary shaft 32 and a movable pulley 34b slidably mounted in the axial direction of the primary shaft 32 facing the fixed pulley 34a. It is configured so that the cone surface spacing of the pulleys 34a and 34b, that is, the pulley groove width can be changed. On the other hand, the secondary shaft 37 is provided with a secondary pulley 35. The secondary pulley 35 has a fixed pulley 35a joined to the secondary shaft 37 and a movable pulley 35b that faces the fixed pulley 35a and is slidably mounted in the axial direction of the secondary shaft 37. It is configured so that the width can be changed.

A chain 36 for transmitting a driving force is hung between the primary pulley 34 and the secondary pulley 35. By changing the groove widths of the primary pulley 34 and the secondary pulley 35 and changing the ratio of the winding diameter of the chain 36 to each of the pulleys 34 and 35 (pulley ratio), the gear ratio is changed steplessly. Here, assuming that the winding diameter of the chain 36 with respect to the primary pulley 34 is Rp and the winding diameter of the chain 36 with respect to the secondary pulley 35 is Rs, the gear ratio i is represented by i = Rs / Rp.

Here, the hydraulic chamber 34c is formed in the primary pulley 34 (movable pulley 34b). On the other hand, a hydraulic chamber 35c is formed in the secondary pulley 35 (movable pulley 35b). The groove widths of the primary pulley 34 and the secondary pulley 35 are set and changed by adjusting the primary hydraulic pressure introduced into the hydraulic chamber 34c of the primary pulley 34 and the secondary hydraulic pressure introduced into the hydraulic chamber 35c of the secondary pulley 35. Will be done.

The hydraulic pressure for shifting the continuously variable transmission 20, that is, the primary hydraulic pressure and the secondary hydraulic pressure described above are controlled by the valve body (control valve) 50. The valve body 50 adjusts the hydraulic pressure discharged from the oil pump 70 by opening and closing the oil passage formed in the valve body 50 by using the spool valve and the solenoid valve (solenoid valve) that moves the spool valve. , Supply to the hydraulic chamber 34c of the primary pulley 34 and the hydraulic chamber 35c of the secondary pulley 35. Further, the valve body 50 also supplies the hydraulic pressure adjusted to the lockup clutch 25, the forward / backward switching mechanism 27, and the like.

Here, with reference to FIG. 2, a configuration of a hydraulic circuit formed in the valve body 50 and supplying hydraulic pressure to the forward / backward switching mechanism 27 and the like described above will be described. FIG. 2 is a diagram showing a hydraulic circuit configuration (main parts only) of the oil pump 70 and the valve body 50.

The oil pump 70 sucks the oil (ATF) stored in the oil pan 590 through the low hydraulic circuit (suction oil passage) 530A and two suction ports (first suction port 706A and second suction port 706B). , The pressure is increased and the oil is discharged from the two discharge ports (first discharge port 707A and second discharge port 707B). In the present embodiment, as the oil pump 70, a 2-port type vane pump having two discharge ports (first discharge port 707A and second discharge port 707B) is used.

The oil pump 70 is a so-called balanced vane pump, and includes a cam ring 701 having an inner peripheral surface having a substantially elliptical cross section, a rotor 702 arranged inside the cam ring 701 and driven by the driving force of an engine, and a rotor 702. It is configured to have a pump shaft 703 that rotatably supports and a plurality of vanes 704 incorporated in grooves formed around the rotor 702.

Each of the plurality of vanes 704 is movable in the radial direction of the rotor 702, and when the rotor 702 rotates, the vanes 704 incorporated in the groove of the rotor 702 pop out by centrifugal force, and the tip thereof is the inner peripheral surface of the cam ring 701. Rotates along the inner surface of the eccentric cam ring 701 in contact with. At this time, the volume of the oil chamber 705 defined by the cam ring 701, the rotor 702, and the vane 704 changes, and the suction / discharge operation is performed.

That is, due to the rotation of the rotor 702, the oil sucked from the first suction port 706A through the low hydraulic circuit 530A is boosted and discharged from the first discharge port 707A to the main (main) hydraulic circuit (line pressure oil passage) 510A. To. Similarly, the oil sucked from the second suction port 706B through the low hydraulic pressure circuit 530A is boosted and discharged from the second discharge port 707B to the sub (secondary) hydraulic circuit 520A.

As described above, the main hydraulic circuit 510A is connected to the first discharge port 707A of the oil pump 70. Further, a sub hydraulic circuit 520A is connected to the second discharge port 707B. The sub-hydraulic circuit 520A is configured to communicate with the main hydraulic circuit 510A via the first switching valve 571. In the main hydraulic circuit 510A, a line pressure control valve (regulator valve) 562 for adjusting the hydraulic pressure (discharge pressure) of the oil discharged from the oil pump 70 to the hydraulic pressure (line pressure) required for the continuously variable transmission 20. Is provided.

The line pressure control valve 562 is connected to a control hydraulic circuit 511A, a main hydraulic circuit 510A, and a low hydraulic circuit (drain oil passage) 530C for discharging oil, which communicate with the line pressure linear solenoid 551 described later. The line pressure control valve 562 houses the spool 562a so as to be slidable in the axial direction. A spring 562b is arranged at the end of the spool 562a, and a pressing force (line pressure control pressure × pressure receiving area) generated by the line pressure linear solenoid 551 and a spring force of the spring 562b ( The spool 562a is driven in the axial direction according to the balance between the urging force) and the pushing force due to the line pressure (line pressure × pressure receiving area), so that the oil discharged from the main hydraulic circuit 510A to the low hydraulic circuit 530C The amount is adjusted and the line pressure is adjusted.

That is, when the pushing force due to the actual line pressure is larger than the pushing force due to the line pressure control pressure, the line pressure control valve 562 communicates the main hydraulic circuit 510A and the low hydraulic circuit 530C with the oil of the main hydraulic circuit 510A. Is discharged through the low hydraulic circuit 530C, so that the line pressure is adjusted so that the pressing force due to the actual line pressure and the pressing force due to the line pressure control pressure match. On the other hand, when the pushing force due to the actual line pressure is smaller than the pushing force due to the line pressure control pressure, the line pressure control valve 562 cuts off the communication between the main hydraulic circuit 510A and the low hydraulic circuit 530C, and the main hydraulic circuit 510A. Stop draining oil from.

The line pressure linear solenoid 551 has a linear solenoid 551a that axially displaces the valve according to the current value applied from the TCU 40 based on the line pressure required for the continuously variable transmission 20, and the linear solenoid 551. The line pressure control pressure is adjusted by adjusting the balance between the supply pressure (pilot pressure) from the control hydraulic circuit (pilot pressure oil passage) 511B and the drain according to the current applied to the 551a. By supplying the regulated line pressure control pressure to the line pressure control valve 562 through the first control hydraulic circuit 511A, the line pressure control valve 562 is driven and controlled as described above.

The second discharge port 707B of the oil pump 70 is communicated with the main hydraulic circuit 510A via the sub hydraulic circuit 520A, the first switching valve 571, and the main hydraulic circuit 510C. Further, the second discharge port 707B of the oil pump 70 is communicated with the low hydraulic circuit 530A via the sub hydraulic circuit 520B, the second switching valve 572 (details will be described later), and the low hydraulic circuit 530B. The first switching valve 571 switches the discharge destination of the oil discharged from the second discharge port 707B between the main hydraulic circuit 510C and the sub hydraulic circuit 520B. Further, the second switching valve 572 switches the discharge destination of the oil flowing from the first switching valve 571 through the sub hydraulic circuit 520B between the sub hydraulic circuit 520C and the low hydraulic circuit 530B.

More specifically, the first switching valve 571 includes a control hydraulic circuit 511C communicating with a control valve (on / off solenoid valve) 553 described later, a sub hydraulic circuit 520A communicating with a second discharge port 707B, and a main hydraulic circuit 510A. It is connected to the main hydraulic circuit 510C that communicates with the main hydraulic circuit 510C and the sub hydraulic circuit 520B that communicates with the second switching valve 572. The first switching valve 571 houses the spool 571a so as to be slidable in the axial direction. A spring 571b is arranged at the end of the spool 571a, and the axial drive (position) of the spool 571a is controlled according to whether or not the switching control pressure is supplied from the control valve 553, and the sub The oil passage communicating with the hydraulic circuit 520A is switched between the main hydraulic circuit 510C and the sub hydraulic circuit 520B.

That is, when the supply of the switching control pressure is stopped from the control valve 553 described later, the first switching valve 571 switches the oil passage (circuit) so as to communicate the sub hydraulic circuit 520A and the main hydraulic circuit 510C. .. Therefore, the oil discharged from the second discharge port 707B is in a full discharge operation state in which the oil discharged from the first discharge port 707B is merged with the oil discharged from the first discharge port 707A. On the other hand, the first switching valve 571 switches the oil passage (circuit) so as to communicate the sub-hydraulic circuit 520A and the sub-hydraulic circuit 520B when the switching control pressure is supplied.

The control valve 553 is an on / off solenoid valve that is electrically connected to the TCU 40 and is driven by a control signal (drive signal) output from the TCU 40 to open / close (open / close). When the oil pump 70 is put into the full discharge operation state, the control valve 553 is closed to stop the supply of the switching control pressure to the first switching valve 571. On the other hand, the control valve 553 is opened when the oil pump 70 is in a semi-discharge (partial discharge) operation state, or when oil is supplied to the forward / backward clutches 29 and 30 via the sub-hydraulic circuit 520B. , The switching control pressure is supplied to the first switching valve 571.

That is, the control valve 553 (TCU40) was discharged from the second discharge port 707B so that the sub hydraulic circuit 520A and the main hydraulic circuit 510C communicate with each other when the oil pump 70 is put into the full discharge operation state. The first switching valve 571 is controlled so that the oil discharge destination is the main hydraulic circuit 510C. On the other hand, the control valve 553 (TCU40) uses the sub-hydraulic pressure when the oil pump 70 is in a semi-discharge (partial discharge) operation state or when oil is supplied to the forward / backward clutches 29 and 30 via the sub-hydraulic circuit 520B. The first switching valve 571 is controlled so that the circuit 520A and the sub-hydraulic circuit 520B communicate with each other, that is, the discharge destination of the oil discharged from the second discharge port 707B is the sub-hydraulic circuit 520B.

As described above, the second switching valve 572 switches the discharge destination of the oil flowing from the first switching valve 571 through the sub hydraulic circuit 520B between the sub hydraulic circuit 520C and the low hydraulic circuit 530B. That is, the second switching valve 572 interrupts the communication between the sub-hydraulic circuit 520B and the sub-hydraulic circuit 520C (opens and closes the sub-hydraulic circuit 520). Hereinafter, the sub-hydraulic circuit 520A, the sub-hydraulic circuit 520B, and the sub-hydraulic circuit 520C may be collectively referred to as the sub-hydraulic circuit 520, and the main hydraulic circuit 510A and the main hydraulic circuit 510B may be collectively referred to as the main hydraulic circuit 510. ..

More specifically, the second switching valve 572 includes a control hydraulic circuit 511D communicating with a control valve (on / off solenoid valve) 554 described later, a sub-hydraulic circuit 520B communicating with the first switching valve 571, and a low hydraulic circuit 530A. It is connected to a low hydraulic circuit 530B that communicates with (the first and second suction ports 706A and 706B of the oil pump 70) and a sub-hydraulic circuit 520C that communicates with the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30). .. The second switching valve 572 houses the spool 572a so as to be slidable in the axial direction. A spring 572b is arranged at the end of the spool 572a, and the axial drive (position) of the spool 572a is controlled according to whether or not the switching control pressure is supplied from the control valve 554, and the sub The oil passage communicating with the hydraulic circuit 520B is switched between the sub-hydraulic circuit 520C and the low hydraulic circuit 530B.

That is, the second switching valve 572 switches the oil passage (circuit) so as to communicate the sub-hydraulic circuit 520B and the sub-hydraulic circuit 520C when the supply of the switching control pressure is stopped from the control valve 554 described later. .. Therefore, the oil discharged from the second discharge port 707B is sent to the forward / reverse advance switching mechanism 27 (forward / backward clutches 29 and 30) via the sub-hydraulic circuit 520C. On the other hand, when the switching control pressure is supplied, the second switching valve 572 switches the oil passage (circuit) so as to communicate the sub-hydraulic circuit 520B and the low-hydraulic circuit 530B. Therefore, the oil discharged from the second discharge port 707B is returned to the low hydraulic pressure circuit 530A (first and second suction ports 706A, 706B) to enter the semi-discharge operation state. As a result, the load on the oil pump 70 is reduced.

The control valve 554 is an on / off solenoid valve that is electrically connected to the TCU 40 and is driven by a control signal (drive signal) output from the TCU 40 to open / close (open / close). When the oil discharged from the second discharge port 707B is sent to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) via the sub-hydraulic circuit 520C, the control valve 554 is closed and the second valve is closed. The supply of the switching control pressure to the switching valve 572 is stopped. On the other hand, when the oil pump 70 is put into the semi-discharge (partial discharge) operation state, the control valve 554 opens and supplies the switching control pressure to the second switching valve 572.

That is, the control valve 554 (TCU40) is a second switching valve so that the sub-hydraulic circuit 520B and the sub-hydraulic circuit 520C communicate with each other when oil is supplied to the forward / backward clutches 29 and 30 via the sub-hydraulic circuit 520C. Controls 572. On the other hand, the control valve 554 (TCU40) controls the second switching valve 572 so that the sub-hydraulic circuit 520B and the low-hydraulic circuit 530B communicate with each other when the oil pump 70 is put into the semi-discharge (partial discharge) operation state. ..

On the other hand, on the downstream side of the branch portion between the main hydraulic circuit 510A and the hydraulic circuit 510D that supplies oil to the variator (primary pulley 34 and secondary pulley 35), and at the confluence portion 525 between the main hydraulic circuit 510B and the sub hydraulic circuit 520C. A third switching valve 573 is interposed on the upstream side (that is, the upstream side of the clutches 29 and 30 (clutch valve 564) constituting the forward / backward switching mechanism 27). The third switching valve 573 opens and closes the main hydraulic circuit 510A, and interrupts the supply of oil from the main hydraulic circuit 510A to the forward / backward clutches 29 and 30 constituting the forward / backward switching mechanism 27.

More specifically, the third switching valve 573 includes a control hydraulic circuit 511D that communicates with the control valve (on / off solenoid valve) 554 described above, and a main hydraulic circuit 510A that communicates with the first discharge port 707A of the oil pump 70. It is also connected to the main hydraulic circuit 510B that communicates with the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30). The third switching valve 573 houses the spool 573a so as to be slidable in the axial direction. A spring 573b is arranged at the end of the spool 573a, and the axial drive (position) of the spool 573a is controlled according to whether or not the switching control pressure is supplied from the control valve 554, and the main The communication between the hydraulic circuit 510A and the main hydraulic circuit 510B is interrupted (the main hydraulic circuit 510 is opened and closed).

That is, the third switching valve 573 closes the main hydraulic circuit 510A when the supply of the switching control pressure is stopped from the control valve 554 described above. Therefore, the supply of oil from the main hydraulic circuit 510A to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) is stopped. On the other hand, the third switching valve 573 opens the main hydraulic circuit 510A when the switching control pressure is supplied. Therefore, oil is supplied from the main hydraulic circuit 510A to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) via the main hydraulic circuit 510B.

As described above, the control valve 554 is an on / off solenoid valve that is electrically connected to the TCU 40 and is driven by a control signal (drive signal) output from the TCU 40 to open / close (open / close). is there. The control valve 554 (TCU40) is closed when the supply of oil from the main hydraulic circuit 510A to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) is stopped, and the valve is switched to the third switching valve 573. Stop the supply of control pressure. On the other hand, when oil is supplied from the main hydraulic circuit 510A to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30), the control valve 554 (TCU40) is opened to set the switching control pressure to the third switching valve. Supply to 573. In the present embodiment, the control (drive) of the second switching valve 572 and the third switching valve 573 is performed by one control valve (control valve 554), but the second switching valve 572 and the third switching valve Each of the 573s may be controlled (driven) by a separate control valve.

A pressure regulating valve (protection valve) 574 is interposed on the downstream side of the second switching valve 572 of the sub-hydraulic circuit 520C. The pressure regulating valve (protection valve) 574 is configured to include, for example, a spring and a valve, and in order to protect the clutches (forward clutch 29, reverse clutch 30) of the forward / backward switching mechanism 27, the hydraulic pressure of the sub hydraulic circuit 520C is applied. When the pressure exceeds a predetermined level, oil (hydraulic pressure) is discharged to the lubrication system.

Further, on the downstream side of the pressure regulating valve (protection valve) 574 of the sub-hydraulic circuit 520C (that is, the downstream side of the second switching valve 572) and on the upstream side of the confluence portion 525 of the main hydraulic circuit 510B and the sub-hydraulic circuit 520C. , One-way valve 575 is interposed. The one-way valve 575 allows oil to flow from the sub-hydraulic circuit 520C to the main hydraulic circuit 510B when the hydraulic pressure of the sub-hydraulic circuit 520C is higher than the hydraulic pressure of the main hydraulic circuit 510B, and the hydraulic pressure of the sub-hydraulic circuit 520C is the main. When the oil pressure is lower than the oil pressure of the oil pressure circuit 510B, the inflow of oil from the main oil pressure circuit 510B to the sub oil pressure circuit 520C is prohibited.

Returning to FIG. 1, the shift control of the continuously variable transmission 20 is executed by the TCU 40. That is, the TCU 40 adjusts the hydraulic pressure supplied to the hydraulic chamber 34c of the primary pulley 34 and the hydraulic chamber 35c of the secondary pulley 35 by controlling the drive of the solenoid valve (solenoid valve) constituting the valve body 50 described above. , The gear ratio of the continuously variable transmission 20 is changed. Further, the TCU 40 adjusts the amount of oil supplied / discharged to the forward clutch 29 or the reverse clutch 30 by controlling the drive of the clutch linear solenoid 552 and the clutch valve 564 constituting the valve body 50 described above, and the forward clutch. 29 or the reverse clutch 30 is engaged / released. Whether the oil is supplied (or discharged) to the forward clutch 29 side or the reverse clutch 30 side is switched by a manual valve 565 configured to move in conjunction with the shift lever 51. Be done.

Here, on the floor (center console) of the vehicle or the like, a shift lever (select lever) 51 is provided to receive an operation of selectively switching the operating state (range) of the continuously variable transmission 20 by the driver. .. A range switch 59 is attached to the shift lever 51 so as to move in conjunction with the shift lever 51 and detect a selected position of the shift lever 51. The range switch 59 is connected to the TCU 40, and the detected selected position of the shift lever 51 is read into the TCU 40. In addition to the drive "D" range and the manual "M" range, the shift lever 51 can selectively switch between the parking "P" range, the reverse "R" range, and the neutral "N" range. That is, the shift lever (select lever) 51 functions as the selection means described in the claims. A switch type select mechanism may be used instead of the shift lever 51.

Here, when the shift lever 51 is operated and the D range (forward travel range) is selected, the manual valve 565 moves to the left side of the drawing, oil is supplied to the hydraulic chamber of the forward clutch 29, and the reverse clutch is used. Oil is discharged from the hydraulic chambers of 30. As a result, the forward clutch 29 is in the engaged state and the reverse clutch 30 is in the released state, and the vehicle can move forward. On the other hand, when the shift lever 51 is operated and the R range (reverse travel range) is selected, the manual valve 565 moves to the right side of the drawing, oil is supplied to the hydraulic chamber of the reverse clutch 30, and the forward clutch 29 Oil is discharged from the hydraulic chamber of. As a result, the reverse clutch 30 is in the engaged state and the forward clutch 29 is in the released state, and the vehicle can move backward. When the shift lever 51 is operated to select the N range or the P range, oil is discharged from the hydraulic chambers of the forward clutch 29 and the hydraulic chambers of the reverse clutch 30. As a result, the forward clutch 29 and the reverse clutch 30 are each released (the transmission of the engine driving force is cut off), and the continuously variable transmission 20 is in the neutral state.

In addition to the above-mentioned turbine rotation speed sensor 56 (turbine rotation speed), the TCU 40 includes an oil temperature sensor 53 that detects the oil temperature of the continuously variable transmission 20 and a main circuit pressure sensor 54 that detects the oil pressure of the main hydraulic circuit 510. , The sub-circuit pressure sensor 55 that detects the hydraulic pressure of the sub-hydraulic circuit 520, the primary pulley rotation sensor 57 that detects the rotation speed of the primary pulley 34, the secondary pulley rotation sensor 58 that detects the rotation speed of the secondary pulley 35, and the like. It is connected. Further, the TCU 40 is connected to the ECU 60 and the like that comprehensively control the engine 10 via a CAN (Control Area Network) 100, for example, so as to be able to communicate with each other.

The TCU 40 and the ECU 60 have their stored contents held by a microprocessor that performs calculations, a ROM that stores programs for causing the microprocessors to execute each process, a RAM that stores various data such as calculation results, and a battery. It is configured to have a backup RAM, an input / output I / F, and the like.

In the ECU 60, the cylinder is determined from the output of the cam angle sensor described above, and the engine speed is obtained from the change in the rotation position of the crankshaft detected by the output of the crank angle sensor. Further, the ECU 60 acquires various information such as the intake air amount, the accelerator pedal opening degree, the air-fuel ratio of the air-fuel mixture, and the water temperature based on the detection signals input from the various sensors described above. Then, the ECU 60 comprehensively controls the engine 10 by controlling various devices such as the fuel injection amount, the ignition timing, and the throttle valve 13 based on the acquired various information.

Further, in the ECU 60, the engine shaft torque (output torque) of the engine 10 is calculated based on the intake air amount detected by the air flow meter 61. Then, the ECU 60 transmits information such as the engine speed, the engine shaft torque, and the accelerator pedal opening degree to the TCU 40 via the CAN 100.

The TCU 40 automatically shifts the gear ratio steplessly according to the driving state of the vehicle (for example, the accelerator pedal opening degree and the vehicle speed) according to the shift map. The shift map corresponding to the automatic shift mode is stored in the ROM in the TCU 40.

In particular, the TCU 40 hydraulically reduces the engagement delay of the forward / backward clutches 29 and 30 while preventing a decrease in line pressure when engaging the forward clutch 29 or the reverse clutch 30 constituting the forward / backward switching mechanism 27. Has a function to control. Therefore, the TCU 40 functionally has a forward / backward clutch control unit 41. In the TCU 40, the function of the forward / backward clutch control unit 41 is realized by executing the program stored in the ROM by the microprocessor.

When the forward / reverse clutch control unit 41 engages the forward clutch 29 or the reverse clutch 30 constituting the forward / backward switching mechanism 27, the first forward / backward clutch control unit 41 reduces the clutch engagement delay while preventing a decrease in line pressure. It controls the drive of the switching valve 571, the second switching valve 572, and the third switching valve 573. That is, the forward / backward clutch control unit 41 functions as the control means described in the claims.

More specifically, the forward / backward clutch control unit 41 drives the first switching valve 571 (second discharge port) when the parking (P) range or the neutral (N) range is selected by the shift lever 51. The discharge destination of the oil (discharged from 707B) is switched to the sub-hydraulic circuit 520B side, and the second switching valve 572 is driven to switch (open) the oil discharge destination to the sub-hydraulic circuit 520C side, and the third switching. The valve 573 is closed.

Therefore, the supply of hydraulic pressure from the main hydraulic circuit 510 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30) is stopped, and from the sub hydraulic circuit 520 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30). Hydraulic pressure is supplied. Then, the forward clutch 29 or the reverse clutch 30 is engaged (initial engagement).

At that time, the forward / backward clutch control unit 41 is the first when the parking (P) range or the neutral (N) range is selected by the shift lever 51 and the engine speed is equal to or less than the predetermined speed (for example, 1000 rpm). 1 The switching valve 571 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520B side, and the second switching valve 572 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520C side (open). 3 It is preferable to close the switching valve 573. By doing so, only at the time of starting (forward side or reverse side) when the engine speed is relatively low (that is, the discharge amount of the oil pump 70 is relatively small and the line pressure tends to decrease), the sub-hydraulic circuit 520 Oil is supplied (oil is filled in the clutch chamber) to the forward / backward clutches 29 and 30 constituting the forward / backward switching mechanism 27.

Further, when the forward / backward clutch control unit 41 selects the parking (P) range or the neutral (N) range by the shift lever 51 and the oil temperature of the continuously variable transmission 20 is a predetermined temperature (for example, 60 ° C.) or higher. In addition, the first switching valve 571 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520B side, and the second switching valve 572 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520C side (open the valve). ), It is preferable to close the third switching valve 573. In this way, the sub-hydraulic clutch is used only in a situation where the oil temperature rises, the viscosity of the oil decreases, and the amount of oil leakage (return amount) increases (that is, the line pressure tends to decrease). From 520, oil is supplied to the forward / backward clutches 29 and 30 constituting the forward / backward switching mechanism 27 (the clutch chamber is filled with oil).

On the other hand, the forward / backward clutch control unit 41 switches the range from the parking (P) range or the neutral (N) range to the drive (D) range or the reverse (R) range by the shift lever 51, and the forward / backward switching mechanism. When the front / rear clutches 29 and 30 constituting 27 are completely engaged, the second switching valve 572 is driven to switch (close) the oil discharge destination to the low hydraulic circuit 530B side, and the third switching valve 573 Is opened, and the first switching valve 571 is driven to switch the discharge destination of the oil discharged from the second discharge port 707B based on the operating state of the continuously variable transmission 20. Whether or not the forward clutch 29 (or the reverse clutch 30) has been engaged can be determined based on, for example, whether or not the differential rotation between the turbine rotation speed and the primary pulley rotation speed is equal to or less than a predetermined rotation speed. ..

Therefore, after the forward clutch 29 or the reverse clutch 30 is engaged (initially engaged), the supply of hydraulic pressure from the sub-hydraulic circuit 520 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30) is stopped, and the main hydraulic pressure is stopped. Hydraulic pressure is supplied from the circuit 510 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30). Here, since the forward clutch 29 or the reverse clutch 30 has already been engaged (initially engaged), it is assumed that the hydraulic pressure supply path to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30) is switched to the main hydraulic circuit 510 side. However, the line pressure does not drop.

At that time, when the forward / backward clutches 29 and 30 are engaged and the hydraulic pressure of the main hydraulic circuit 510 becomes higher than the hydraulic pressure of the sub hydraulic circuit 520, the forward / backward clutch control unit 41 receives the second switching valve 572. It is preferable to switch (close) the oil discharge destination to the low hydraulic circuit 530B side and open the third switching valve 573. By doing so, the backflow from the sub-hydraulic circuit 520C to the main hydraulic circuit 510B (that is, the backflow from the clutch pressure side to the line pressure side) is prevented, and the fastening force of the forward / backward clutches 29 and 30 which may be caused by the backflow is prevented. The drop is prevented.

Next, the operation of the control device 1 of the continuously variable transmission will be described with reference to FIG. FIG. 3 is a flowchart showing a processing procedure of clutch control of the forward / backward switching mechanism 27 by the control device 1 of the continuously variable transmission. This process is repeatedly executed at predetermined time intervals (for example, every 10 ms) in the TCU 40.

First, in step S100, it is determined whether or not the engine speed is equal to or less than a predetermined speed (for example, 1000 rpm). Here, when the engine speed is higher than the predetermined number of times, the process is temporarily exited, and hydraulic pressure is supplied from the main hydraulic circuit 510 to the forward / backward clutches 29 and 30. On the other hand, when the engine speed is equal to or less than the predetermined speed, the process shifts to step S102.

In step S102, it is determined whether or not the oil temperature of the continuously variable transmission 20 is equal to or higher than a predetermined temperature (for example, 60 ° C.). Here, when the oil temperature is lower than the predetermined temperature, the main process is temporarily exited, and hydraulic pressure is supplied from the main hydraulic circuit 510 to the forward / backward clutches 29 and 30. On the other hand, when the oil temperature is equal to or higher than the predetermined temperature, the process shifts to step S104.

In step S104, the shift lever 51 determines whether or not the N range (neutral range) or the P range (parking range) is selected. Here, when the N range or the P range is selected, the process shifts to step S106. On the other hand, when the N range or the P range is not selected, the process shifts to step S108.

In step S106, the oil passage is switched so that hydraulic pressure is supplied from the sub-hydraulic circuit 520 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30). More specifically, the first switching valve 561 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520B side, and the second switching valve 572 is driven to move the oil discharge destination to the sub-hydraulic circuit 520C side. It is switched (opened) and the third switching valve 573 is closed. After that, the process shifts to step S108.

In step S108, it is determined whether or not the range is switched from the N range or the P range to the D range (drive range) or the R range (reverse range) by the shift lever 51. Here, if the range is not switched from the N range or the P range to the D range or the R range, the process is temporarily exited. On the other hand, when the range is switched from the N range or the P range to the D range or the R range, the process shifts to step S110.

In step S110, the forward clutch 29 (or reverse clutch 30) of the forward / backward switching mechanism 27 is started to be engaged. That is, the clutch linear solenoid 552 is driven, and hydraulic pressure is supplied to the forward clutch 29 (or reverse clutch 30) via the clutch valve 564 and the manual valve 565.

Next, in step S112, for example, whether or not the engagement of the forward clutch 29 (or the reverse clutch 30) is completed based on whether or not the differential rotation between the turbine rotation speed and the primary pulley rotation speed is equal to or less than a predetermined rotation speed. Judgment is made. Here, when the engagement of the forward clutch 29 (or the reverse clutch 30) is completed, the process shifts to step S114. On the other hand, when the engagement of the forward clutch 29 (or the reverse clutch 30) is not completed, this process is repeatedly executed until the engagement of the forward clutch 29 (or the reverse clutch 30) is completed.

In step S114, it is determined whether or not the hydraulic pressure of the main hydraulic circuit 510 is higher than the hydraulic pressure of the sub hydraulic circuit 520. Here, when the hydraulic pressure of the main hydraulic circuit 510 is higher than the hydraulic pressure of the sub hydraulic circuit 520, the process shifts to step S116. On the other hand, when the hydraulic pressure of the main hydraulic circuit 510 is equal to or lower than the hydraulic pressure of the sub hydraulic circuit 520, this process is repeatedly executed until the hydraulic pressure of the main hydraulic circuit 510 becomes higher than the hydraulic pressure of the sub hydraulic circuit 520.

In step S116, the supply of hydraulic pressure from the sub-hydraulic circuit 520 to the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30) is stopped, and the forward / backward switching mechanism 27 (forward clutch 29, reverse clutch 30) is stopped from the main hydraulic circuit 510. The oil passage is switched so that hydraulic pressure is supplied to). More specifically, the second switching valve 572 is driven to switch the oil discharge destination to the low hydraulic circuit 530B side (closed), and the third switching valve 573 is opened. Further, based on the operating state of the continuously variable transmission 20, the first switching valve 571 is driven to switch the discharge destination of the oil discharged from the second discharge port 707B. After that, the process is temporarily exited.

As described in detail above, according to the present embodiment, the discharge destination of the oil discharged from the second discharge port 707B of the oil pump 70 is switched between the main hydraulic circuit 510A and the sub hydraulic circuit 520B. Oil is supplied to the 1 switching valve 571, the second switching valve 572 that is interposed in the sub-hydraulic circuit 520B and opens and closes the sub-hydraulic circuit 520B, the main hydraulic circuit 510A, and the variator (primary pulley 34 and secondary pulley 35). It is provided with a third switching valve 273 that is interposed on the downstream side of the branch portion with the hydraulic circuit 510D and on the upstream side of the confluence portion 525 between the in hydraulic circuit 510B and the sub hydraulic circuit 520C to open and close the main hydraulic circuit 510A. There is. Then, when the parking (P) range or the neutral (N) range is selected by the shift lever 51, the first switching valve 261 is driven to switch the oil discharge destination to the sub-hydraulic circuit 520B side, and the second switching valve 261 is used. The switching valve 572 is switched (opened) to the sub-hydraulic circuit 520C side, and the third switching valve 573 is closed. Further, the shift lever 51 switches the range from the parking (P) range or the neutral (N) range to the drive (D) range or the reverse (R) range, and the forward / backward clutch 29, which constitutes the forward / backward switching mechanism 27, When 30 is fastened, the second switching valve 572 is switched (closed) to the low hydraulic circuit 530B side, and the third switching valve 573 is opened.

Therefore, by controlling the first switching valve 571, the second switching valve 572, and the third switching valve 573, the main hydraulic circuit 510 and the sub hydraulic circuit 520 are made independent for each of the discharge ports 707A and 707B of the oil pump 70. In a state where the main hydraulic circuit 510 and the forward / backward switching mechanism 27 (forward / backward clutches 29, 30) are cut off, the sub hydraulic circuit 520 starts the forward / backward switching mechanism 27 (forward / backward clutches 29, 30). ) Can be supplied with oil. That is, when oil is supplied to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30), the communication between the main hydraulic circuit 510 and the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) is cut off. By supplying oil from the sub-hydraulic circuit 520 to the forward / backward switching mechanism 27 (forward / backward clutches 29 and 30) without being affected by the decrease in line pressure and preventing the decrease in line pressure. The forward / backward clutches 29 and 30 can be engaged (initial engagement) faster. As a result, when the forward clutch 29 or the reverse clutch 30 constituting the forward / backward switching mechanism 27 is engaged, it is possible to shorten the engagement delay of the forward / backward clutches 29 and 30 while preventing a decrease in the line pressure. ..

According to the present embodiment, when the forward / backward clutches 29 and 30 are engaged and the hydraulic pressure of the main hydraulic circuit 510 becomes higher than the hydraulic pressure of the sub hydraulic circuit 520, the second switching valve 572 is the low hydraulic pressure circuit 530B. The valve is switched to the side (closed), and the third switching valve 573 is opened. Therefore, backflow from the sub-hydraulic circuit 520C to the main hydraulic circuit 510B (that is, backflow from the clutch pressure side to the line pressure side) can be prevented. Therefore, it is possible to prevent a decrease in the fastening force of the forward / backward clutches 29 and 30 that may occur when a backflow occurs.

According to the present embodiment, when the parking (P) range or the neutral (N) range is selected by the shift lever 51 and the engine speed is equal to or less than the predetermined speed, the first switching valve 571 is driven to charge the oil pressure. The discharge destination is switched to the sub-hydraulic circuit 520B side, the second switching valve 572 is switched to the low hydraulic circuit 530B side (closed), and the third switching valve 573 is closed. Therefore, only when the engine speed is relatively low (that is, the discharge amount of the oil pump 70 is relatively small and the line pressure is likely to decrease) (forward side or reverse side), the sub-hydraulic circuit 520 switches between forward and backward movements. Oil can be supplied (the clutch chamber is filled with oil) to the forward / backward clutches 29 and 30 constituting the mechanism 27.

According to the present embodiment, the first switching valve 571 is driven when the parking (P) range or the neutral (N) range is selected by the shift lever 51 and the oil temperature of the continuously variable transmission 20 is equal to or higher than a predetermined temperature. The discharge destination of the oil discharged from the second discharge port 707B is switched to the sub-hydraulic circuit 520B side, and the second switching valve 572 is switched (opened) to the sub-hydraulic circuit 520C side, and the third switching valve is opened. 573 is closed. Therefore, the sub-hydraulic circuit 520 is limited to the situation where the oil temperature rises, the viscosity of the oil decreases, and the amount of oil leakage (return amount) increases (that is, the line pressure tends to decrease). Oil can be supplied to the forward / backward clutches 29 and 30 constituting the forward / backward switching mechanism 27 (the clutch chamber is filled with oil).

According to this embodiment, when the sub-hydraulic circuit 520 is closed, the discharge destination of the oil discharged from the second discharge port 707B is on the low hydraulic circuit 530B (suction port 706A, 706B of the oil pump 70) side. Can be switched to. Therefore, the operating state of the oil pump 70 can be switched between the full discharge operating state and the partial discharge (half discharge) operating state based on the operating state of the continuously variable transmission 20. Therefore, the load on the oil pump 70 can be appropriately reduced.

According to the present embodiment, when the hydraulic pressure of the sub hydraulic circuit 520C is higher than the hydraulic pressure of the main hydraulic circuit 510B, which is interposed on the downstream side of the second switching valve 572 of the sub hydraulic circuit 520C, the sub hydraulic circuit 520C is used as the main. A one-way valve that allows the inflow of oil into the hydraulic circuit 510B and prohibits the inflow of oil from the main hydraulic circuit 510B into the sub-hydraulic circuit 520C when the oil pressure in the sub-hydraulic circuit 520C is lower than the oil pressure in the main hydraulic circuit 510B. It also has 575. Therefore, it is possible to prevent backflow from the main hydraulic circuit 510B to the sub hydraulic circuit 520C.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, the hydraulic circuit configuration of the valve body 50 shown in the above embodiment (FIG. 2) is an example, and is not limited to the hydraulic circuit configuration.

In the above embodiment, the present invention has been applied to a chain type continuously variable transmission (CVT), but it may be applied to, for example, a belt type continuously variable transmission instead of the chain type continuously variable transmission. it can.

Further, in the above embodiment, the forward / backward switching mechanism 27 is arranged in the front stage of the primary pulley 34, but it may be arranged in the rear stage of the secondary pulley 35.

Further, in the above embodiment, the spool valve is driven by the solenoid valve, but the spool valve may be driven by, for example, a stepping motor instead of the solenoid valve.

Further, in the above embodiment, the vane pump is used as the oil pump 70, but the oil pump 70 is not limited to the vane pump, and for example, an internal gear pump such as a trochoid pump or another type of pump may be used. Good.

In the above embodiment, the ECU 60 that controls the engine 10 and the TCU 40 that controls the continuously variable transmission 20 are configured by separate hardware, but they may be configured by integrated hardware.

1 Continuously variable transmission control device 10 Engine 20 Continuously variable transmission 21 Torque converter 27 Forward / backward switching mechanism 28 Planetary gear train 29 Forward clutch 30 Reverse clutch (reverse brake)
34 Primary pulley 35 Secondary pulley 36 Chain 40 TCU
41 Forward / backward clutch control unit 50 Valve body (control valve)
51 Shift lever 53 Oil temperature sensor 54 Main circuit pressure sensor 55 Sub circuit pressure sensor 56 Turbine speed sensor 57 Primary pulley rotation sensor 58 Secondary pulley rotation sensor 59 Range switch 60 ECU
70 oil pump 100 CAN
510A, 510B, 510C, 510D Main hydraulic circuit 511A, 511B, 511C, 511D Control hydraulic circuit 520A, 520B, 520C Sub-hydraulic circuit 530A, 530B, 530C Low hydraulic circuit 551 Line pressure linear solenoid 552 Clutch linear solenoid 552, 554 Control valve 562 Line pressure control valve 564 Clutch valve 565 Manual valve 571 1st switching valve 572 2nd switching valve 573 3rd switching valve 574 Pressure regulating valve (protection valve)
575 One-way valve 701 Cam ring 702 Rotor 703 Pump shaft 704 Vane 705 Oil chamber 706A 1st suction port 706B 2nd suction port 707A 1st discharge port 707B 2nd discharge port

Claims (5)

A selection means that accepts operations to select the range of a continuously variable transmission,
A forward / backward switching mechanism provided between the engine and the drive wheels to switch between forward and reverse rotation of the drive wheels,
An oil pump having a first discharge port and a second discharge port for discharging boosted oil,
The main hydraulic circuit communicated with the first discharge port and
A first switching valve that switches the discharge destination of the oil discharged from the second discharge port between the main hydraulic circuit and the sub-hydraulic circuit that communicates with the clutch that constitutes the forward / backward switching mechanism.
A second switching valve that is interposed in the sub-hydraulic circuit and opens and closes the sub-hydraulic circuit,
A third switch that opens and closes the main hydraulic circuit by being interposed on the downstream side of the branch portion between the main hydraulic circuit and the hydraulic circuit that supplies oil to the variator and on the upstream side of the clutch that constitutes the forward / backward switching mechanism. With the valve
A control means for controlling the drive of the first switching valve, the second switching valve, and the third switching valve is provided.
The control means
When the parking range or the neutral range is selected by the select means, the first switching valve is driven to switch the discharge destination of the oil discharged from the second discharge port to the sub-hydraulic circuit side, and the second The switching valve is opened and the third switching valve is closed.
From the parking range or the neutral range by the select means, range is switched to the drive range or a reverse range, and, when the clutch constituting the forward-reverse switching mechanism is entered into, and closes the front Stories second switching valve , Open the third switching valve,
A continuously variable transmission control device characterized by this. The control means closes the second switching valve and opens the third switching valve when the clutch is engaged and the hydraulic pressure of the main hydraulic circuit becomes higher than the hydraulic pressure of the sub hydraulic circuit. The control device for a continuously variable transmission according to claim 1, wherein the valve is used. When the parking range or the neutral range is selected by the select means and the engine speed is equal to or less than a predetermined speed, the control means drives the first switching valve and discharges the engine from the second discharge port. The continuously variable transmission according to claim 1 or 2, wherein the discharge destination of the oil is switched to the sub-hydraulic circuit side, the second switching valve is opened, and the third switching valve is closed. Control device. When the parking range or the neutral range is selected by the select means and the oil temperature of the continuously variable transmission is equal to or higher than a predetermined temperature, the control means drives the first switching valve to drive the second discharge port. Any of claims 1 to 3, wherein the discharge destination of the oil discharged from the oil is switched to the sub-hydraulic circuit side, the second switching valve is opened, and the third switching valve is closed. The control device for a continuously variable transmission according to item 1. The second switching valve is characterized in that, when the sub-hydraulic circuit is closed, the discharge destination of the oil discharged from the second discharge port is switched to the suction port of the oil pump. The control device for a continuously variable transmission according to any one of 3.

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