JP2010139029A - Controller for belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a change of a speed change ratio from being erroneously determined because of leakage of a pressure oil, when increasing a belt tension by generation of a moderate acceleration request, in case of a fixed speed change ratio. <P>SOLUTION: This controller for a belt type continuously variable transmission includes a flow control valve for fixing the speed change ratio while maintaining, at constant, a pressure oil amount held in the first hydraulic chamber of the first pulley. The controller for the belt type continuously variable transmission includes: an actuation amount determining means (step S2) for determining whether an acceleration pedal is actuated or not when the speed change ratio is fixed; a speed change determining means (step S3) for determining whether downshift is generated or not, when the acceleration pedal is actuated to increase the tension; a continuing means for continuing enclosure control when the downshift is generated; a pressure oil leakage determining means (step S5) for determining whether the acceleration pedal is returned or not when the enclosure control is continued, and whether the pressure oil leakage is generated or not; and a reblocking means (step S6) for increasing the pressure oil amount held in the first hydraulic chamber, when the pressure oil leakage is generated, and for controlling thereafter an oil passage to be blocked. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a belt-type continuously variable transmission configured to transmit engine power to a pulley, and more particularly to a belt-type continuously variable transmission capable of blocking an oil passage connected to a hydraulic chamber for controlling a gear ratio. The present invention relates to a transmission control device.

  Conventionally, it is known that a continuously variable transmission is provided in a power transmission path from an engine of a vehicle to wheels, and the efficiency of the engine is optimized by continuously changing the speed ratio of the continuously variable transmission. As this continuously variable transmission, a belt-type continuously variable transmission and a toroidal-type continuously variable transmission are known, and an example of the belt-type continuously variable transmission is described in Patent Document 1 below. The belt-type continuously variable transmission described in Patent Document 1 is configured such that the torque of the internal combustion engine is transmitted to the belt-type continuously variable transmission via a forward / reverse switching device. This belt-type continuously variable transmission has a driving pulley and a driven pulley, and a belt that is wound around each pulley and transmits a driving force from a driving force source. Each pulley is provided with a clamping pressure generating hydraulic chamber that applies clamping pressure to the belt by hydraulic pressure. Of each clamping pressure generating hydraulic chamber, the hydraulic oil is opened in the direction of supplying hydraulic oil to the driving pulley clamping pressure generating device, and the hydraulic oil supply / discharge valve rotates integrally with the driving pulley, and the piston is driven by the hydraulic pressure of the driving hydraulic chamber. By actuating the actuator, the hydraulic oil supply / discharge valve is forcibly opened, and when the hydraulic oil supply / discharge valve is forcibly opened by this actuator, the actuator operates in the clamping pressure generating hydraulic chamber of the drive pulley. Hydraulic oil supply / discharge control means for controlling the gear ratio by supplying hydraulic oil or discharging hydraulic oil from the hydraulic oil supply / discharge chamber, and gear ratio detection means for detecting the gear ratio are provided. This gear ratio is obtained by detecting the input rotation speed and the output rotation speed of the belt type continuously variable transmission.

  When the detected gear ratio changes when the hydraulic oil supply / discharge valve is closed and the hydraulic oil is trapped in the clamping pressure generating hydraulic chamber of the drive pulley and the gear ratio is fixed, the actuator The hydraulic oil supply / discharge valve is forcibly opened to control the hydraulic oil to be supplied to the clamping pressure generating hydraulic chamber of the drive pulley. Thereby, the axial position of the fixed sheave with respect to the movable sheave of the pulley can be kept constant. Therefore, it is said that even if the hydraulic oil in the clamping pulley generating pressure hydraulic chamber leaks and the gear ratio increases, the gear ratio can be restored to the fixed state. A technique for confining pressure oil in a hydraulic chamber that controls the gear ratio of the belt-type continuously variable transmission is also described in Patent Document 2.

JP 2008-101732 A JP 2006-300270 A

  If a moderate acceleration request is generated while the speed ratio of the belt-type continuously variable transmission is fixed, in order to maintain the speed ratio of the belt-type continuously variable transmission and satisfy the acceleration request There is a case where control is performed to increase the engine torque and increase the hydraulic pressure in the hydraulic pressure chamber for generating the clamping pressure of the driven pulley. By this control, the clamping pressure applied from the driven pulley to the belt increases, the belt tension increases, and the transmission torque increases. By the way, when air is mixed in the clamping pressure generating hydraulic chamber of the drive pulley, the air is a compressible fluid. Therefore, when the belt tension is increased, the air is compressed and the movable sheave is pivoted. Shifting occurs in a direction that inevitably operates in the direction and the gear ratio becomes relatively large. At this time, in the technique described in Patent Document 1, it is determined by the gear ratio detection means that the gear ratio has increased, that is, it is erroneously determined that the hydraulic oil has leaked, and the hydraulic oil supply / discharge valve is forced by the actuator. And the hydraulic oil is supplied to the drive pressure generating hydraulic chamber of the drive pulley, causing inadvertent shifting.

  The present invention has been made paying attention to the technical problem described above. When the transmission gear ratio is fixed, when a moderate acceleration request is generated and the torque of the power source is increased, the hydraulic oil leaks. It is an object of the present invention to provide a control device for a belt type continuously variable transmission that can prevent erroneous determination that the gear ratio has changed due to the above.

  In order to achieve the above-mentioned object, the invention of claim 1 includes a first pulley and a second pulley to which power output from an engine is transmitted and a belt is wound, and the first pulley A movable piece operable in a direction along the rotation center line, and a fixed piece inoperable in a direction along the rotation center line, and is supplied with pressure oil so that the fixed piece becomes the rotation center line. A first hydraulic chamber that generates a thrust force in a direction along the direction, an oil passage through which the pressure oil supplied to the first hydraulic chamber and the pressure oil discharged from the first hydraulic chamber pass, and pressure oil are supplied. And a second hydraulic chamber for generating a clamping pressure to be applied to the belt from the second pulley, and shuts off the oil passage to maintain a constant amount of pressure oil held in the first hydraulic chamber. To maintain a constant gear ratio between the first pulley and the second pulley. In a control device for a belt-type continuously variable transmission having a quantity control valve, when the enclosing control is performed to shut off the oil passage by the flow rate control valve and keep the speed ratio constant, Depressing amount determining means for determining whether or not the accelerator pedal is depressed by a small amount, and the stepping amount determining means determine that the accelerator pedal has been depressed by a very small amount and increase the engine torque, and the tension of the belt When the control for increasing the hydraulic pressure in the second hydraulic chamber is performed to increase the pressure, the movable piece of the first pulley moves in the direction along the rotation center line due to the increase in the tension of the belt. Shift determination means for determining whether or not a shift has occurred in which the air in the first hydraulic chamber is compressed and the gear ratio becomes relatively large, and by the shift determination means, When it is determined that a shift has occurred in which the gear ratio is relatively large due to the compression of the air, the oil flow passage is shut off by the flow rate control valve and the sealing control for keeping the gear ratio constant is continued. And the continuation means, when the control to keep the gear ratio constant is continued, the accelerator pedal is returned to reduce the engine torque, and the hydraulic pressure in the second hydraulic chamber decreases. When the belt tension is lowered, it is determined whether or not there is a leak of pressure oil in the first hydraulic chamber depending on whether or not a shift has occurred in which the gear ratio becomes relatively small. When it is determined by the pressure oil leakage determination means and the pressure oil leakage determination means that pressure oil leakage has occurred in the first hydraulic chamber, the oil passage is opened by the flow control valve; and , Via its oil passage Re-blocking means for supplying pressure oil to one hydraulic chamber, increasing the amount of pressure oil held in the first hydraulic chamber, and then performing control to block the oil passage again by the flow rate control valve; It is characterized by being.

  The invention according to claim 2 has a first pulley and a second pulley to which the power output from the engine is transmitted and the belt is wound, and the first pulley operates in a direction along its rotation center line. It has a movable piece that can be moved and a fixed piece that is not operable in the direction along the rotation center line, and is supplied with pressure oil to generate a thrust that presses the fixed piece in the direction along the rotation center line. A first hydraulic chamber, an oil passage through which pressure oil supplied to the first hydraulic chamber and pressure oil discharged from the first hydraulic chamber pass, and pressure oil is supplied from the second pulley to the belt A second hydraulic chamber for generating a clamping pressure to be applied, and the oil passage is shut off to maintain a constant amount of pressure oil held in the first hydraulic chamber, and the first pulley and the second pulley. And a flow rate control valve for maintaining a constant gear ratio between the belt and the belt Whether or not the accelerator pedal of the vehicle has been depressed a little when the enclosing control is performed to keep the speed ratio constant by blocking the oil passage by the flow rate control valve in the control device of the continuously variable transmission. In order to increase the engine torque and to increase the belt tension, the second hydraulic pressure is determined by the depression amount determining means for determining whether the accelerator pedal is depressed by a small amount. When control is performed to increase the hydraulic pressure in the chamber, the movable piece of the first pulley moves in the direction along the rotation center line due to the increase in the belt tension, and the air in the first hydraulic chamber is compressed. Shift determination means for determining whether or not a shift in which the gear ratio becomes relatively large has occurred, and the shift determination means compresses the air in the first hydraulic chamber so that the gear ratio is When it is determined that a gear shift that is relatively large has occurred, a continuation means that continues the sealing control that shuts off the oil passage by the flow rate control valve and keeps the gear ratio constant, and the continuation means When the enclosing control for keeping the transmission ratio constant by shutting off the oil passage is continued, the time from the start of the shift at which the transmission ratio becomes relatively large is a predetermined time. The elapsed time determination means for determining whether or not the time has elapsed, and the elapsed time determination means, the time from the start of the shift at which the gear ratio becomes relatively large has passed a predetermined time. If it is determined, the oil passage is opened by the flow rate control valve, and pressure oil is supplied to the first hydraulic chamber via the oil passage and is held in the first hydraulic chamber. By increasing the amount of pressure oil, And a gear ratio control means for performing control to minimize the gear ratio.

  The invention according to claim 3 has a first pulley and a second pulley to which the power output from the engine is transmitted and the belt is wound, and the first pulley operates in a direction along its rotation center line. It has a movable piece that can be moved and a fixed piece that is not operable in the direction along the rotation center line, and is supplied with pressure oil to generate a thrust that presses the fixed piece in the direction along the rotation center line. A first hydraulic chamber, an oil passage through which pressure oil supplied to the first hydraulic chamber and pressure oil discharged from the first hydraulic chamber pass, and pressure oil is supplied from the second pulley to the belt A second hydraulic chamber for generating a clamping pressure to be applied, and the oil passage is shut off to maintain a constant amount of pressure oil held in the first hydraulic chamber, and the first pulley and the second pulley. And a flow rate control valve for maintaining a constant gear ratio between the belt and the belt Whether or not the accelerator pedal of the vehicle has been depressed a little when the enclosing control is performed to keep the speed ratio constant by blocking the oil passage by the flow rate control valve in the control device of the continuously variable transmission. In order to increase the engine torque and to increase the belt tension, the second hydraulic pressure is determined by the depression amount determining means for determining whether the accelerator pedal is depressed by a small amount. When control is performed to increase the hydraulic pressure in the chamber, the movable piece of the first pulley moves in the direction along the rotation center line due to the increase in the belt tension, and the air in the first hydraulic chamber is compressed. And a first shift determining means for determining whether or not a first shift in which the gear ratio is relatively large has occurred, and the air in the first hydraulic chamber is compressed by the shift determining means. When it is determined that a gear shift in which the gear ratio is relatively large has occurred, continuation means for continuing sealing control for blocking the oil passage by the flow rate control valve and maintaining the gear ratio constant; and the continuation When the control for maintaining the gear ratio constant is continued by the means, the accelerator pedal is returned to reduce the engine torque, and the hydraulic pressure in the second hydraulic chamber is reduced to reduce the belt pressure. In order to increase the engine torque and increase the belt tension after the accelerator pedal is stepped in again by a small amount after the gear ratio becomes relatively small when the tension is lowered. When the control for increasing the hydraulic pressure in the second hydraulic chamber is performed, the movable piece of the first pulley moves in the direction along the rotation center line due to the increase in the tension of the belt. The second speed change judging means for judging whether or not the second speed change in which the fluid in the pressure chamber is compressed and the speed change ratio becomes relatively large has occurred, and the second speed change judgment means makes the speed change ratio relatively When it is determined that the second speed change that becomes large is generated, the oil passage is opened by the flow rate control valve, and pressure oil is supplied to the first hydraulic chamber via the oil passage. Re-blocking means for increasing the amount of pressure oil held in the first hydraulic chamber and performing control to minimize the speed ratio, and then performing control to block the oil passage by the flow rate control valve; It is characterized by having.

  According to the first aspect of the present invention, when the enclosing control is performed to fix the speed ratio of the belt-type continuously variable transmission, the accelerator pedal is depressed a little to increase the engine torque, and the belt tension is increased. Thus, even when the air in the first hydraulic chamber is compressed, the belt winding radius of the first pulley is reduced, and the downshift occurs, the enclosure control is continued. If the upshift does not occur even when the accelerator pedal is returned, it is determined that the hydraulic oil leaked from the first hydraulic chamber, and the amount of pressurized oil retained in the first hydraulic chamber is increased by temporarily opening the oil passage. Then, the enclosure control is executed again. Thereby, erroneous determination can be prevented.

  According to the invention of claim 2, when the enclosing control is performed to fix the speed ratio of the belt type continuously variable transmission, the accelerator pedal is depressed a little to increase the engine torque, and the belt tension is increased. Thus, even when the air in the first hydraulic chamber is compressed, the belt winding radius of the first pulley is reduced, and the downshift occurs, the enclosure control is continued. When a predetermined time has elapsed since the downshift occurred, the oil passage is once opened, the amount of pressure oil retained in the first hydraulic chamber is increased, a shift is performed to minimize the gear ratio, and the sealing is performed again. Execute control. As a result, the state where the engine operating point deviates from the optimum fuel consumption line can be prevented from continuing for a long time, and the fuel consumption of the engine is improved.

  According to the invention of claim 3, when the enclosing control for fixing the gear ratio of the belt type continuously variable transmission is performed, the accelerator pedal is depressed a little to increase the engine torque, and the belt tension is increased. Thus, even when the air in the first hydraulic chamber is compressed, the belt winding radius of the first pulley is reduced, and the first downshift occurs, the enclosure control is continued. Then, when the accelerator pedal is returned and upshifted, and the accelerator pedal is depressed by a small amount again, and the second downshift occurs on the same principle as described above, the oil passage is once opened and the first hydraulic pressure is released. The amount of pressure oil retained in the chamber is increased, a gear shift that minimizes the gear ratio is performed, and sealing control is executed again. As a result, the state where the engine operating point deviates from the optimum fuel consumption line can be prevented from continuing for a long time, and the fuel consumption of the engine is improved.

  Next, the present invention will be described based on a specific example shown in the drawings. FIG. 2 is a conceptual diagram showing a belt type continuously variable transmission according to the present invention, FIG. 3 is a partial sectional view showing the configuration of a belt type continuously variable transmission, and FIG. It is a figure which shows a hydraulic circuit. The belt type continuously variable transmission of FIG. 2 is mounted on a vehicle, and a torque of a vehicle engine (not shown) is transmitted to the belt type continuously variable transmission.

  The belt type continuously variable transmission has a primary shaft 15 and a secondary shaft (not shown). The primary shaft 15 is provided with a primary pulley (drive pulley) 1, and the secondary shaft is provided with a secondary pulley (driven pulley) 2. The primary shaft 15 is supported to be rotatable about a rotation center line (not shown), and the secondary shaft is supported to be rotatable about a rotation center line (not shown). The primary shaft 15 and the secondary shaft are arranged in parallel. The primary pulley 1 includes a fixed sheave 1a that does not move in a direction along the rotation center line of the primary shaft 15, and a movable sheave 1b that is attached to the primary shaft 15 so as to approach and separate from the fixed sheave 1a. I have. Further, a hydraulic actuator 12 is provided for moving the movable sheep 1b in a direction along the rotation center line. The hydraulic actuator 12 is of a hydraulic cylinder type having a movable sheave 1 b as a piston, and an annular cylinder 10 is fixed to the primary shaft 15. A movable sheave 1b is provided inside the cylindrical portion of the annular cylinder 10, and a hydraulic chamber 1c is formed between the cylinder 10 and the movable sheave 1b. Further, the movable sheave 1B has a cylindrical portion, and an O-ring is attached between the cylindrical portion and the cylindrical portion of the cylinder 10 to form a seal surface. Pressure oil is supplied to the hydraulic chamber 1c, and a thrust that presses the movable sheave 1b toward the fixed sheave 1a is generated by the hydraulic pressure. On the other hand, the secondary pulley 2 has a fixed sheave 2a and a movable sheave 2b. Pressure oil is supplied to a hydraulic chamber (not shown), and the thrust applied to the movable sheave 2b by the hydraulic pressure is controlled. In this configuration, the clamping pressure applied to the belt 3 is controlled. A technique for controlling the clamping pressure of the secondary pulley 2 is described in, for example, Japanese Patent Laid-Open No. 2005-180561.

  Next, the configuration of the hydraulic control device 102 that controls the hydraulic pressure in the hydraulic chamber 1c and the hydraulic chamber 2c of the belt type continuously variable transmission will be described with reference to FIG. First, an oil pump 18 driven by the power of an engine (not shown) is provided. When the oil pump 18 is driven, the oil stored in the oil pan 27 is sucked and the oil is discharged from the oil pump 18. A line pressure control valve (primary regulator valve) 19 for controlling the oil pressure (line pressure PL) of oil discharged from the oil pump 18 to the oil passage R1 is provided. Here, the line pressure control valve 19 is constituted by a solenoid valve. The solenoid valve is configured so that the output hydraulic pressure of the oil pump 18 can be adjusted to a line pressure PL corresponding to a required driving force represented by a vehicle speed, an accelerator opening, and the like. The solenoid valve is configured to regulate the oil pressure in the oil passage R1 by duty control that repeatedly turns the current on and off.

  Further, an oil passage R2 for supplying a part of the pressure oil in the oil passage R1 to the hydraulic chamber 2c is provided, and a secondary pressure control device (secondary regulator valve) 20 for controlling the hydraulic pressure of the hydraulic chamber 2c is provided. ing. The secondary pressure control device 20 has a solenoid valve or the like, and is configured to adjust the hydraulic pressure in the hydraulic chamber 2c by duty control that repeatedly turns on and off the current.

  In addition, an oil passage R3 is connected to the oil passage R1 with a constant pressure control device 22 interposed therebetween. The constant pressure control device 22 adjusts the oil pressure in the oil passage R3 to be constant. Further, the oil passage R <b> 3 is connected to the speed increasing solenoid valve 23 and the speed reducing solenoid valve 24. The speed increasing solenoid valve 23 and the speed reducing solenoid valve 24 are valves for controlling the gear ratio of the belt type continuously variable transmission 1. The speed increasing electromagnetic valve 23 is constituted by a solenoid valve, and has a port (input port) 23a and a port (output port) 23b, and the port 23a is connected to the oil passage R3. When the speed increasing solenoid valve 23 is energized (ON), the signal pressure output from the port 23b is high, and when the speed increasing solenoid valve 23 is not energized (OFF), the port The signal pressure output from 23b is a low pressure.

  On the other hand, the deceleration solenoid valve 24 is constituted by a solenoid valve, and has a port (input port) 24a and a port (output port) 24b, and the port 24a is connected to the oil passage R3. When the deceleration solenoid valve 24 is turned on (on), the signal pressure output from the port 24b becomes high, and when the deceleration solenoid valve 24 is turned off (off), the port 24b The output signal pressure is a low pressure.

  In order to control the gear ratio of the belt type continuously variable transmission, an acceleration flow control valve 25 and a deceleration flow control valve 26 are provided. The speed increasing flow control valve 25 has ports 25a, 25b, 25c, 25d and a spool 25s. The port 25a is connected to the output port 23b, the port 25c is connected to the oil path R1, the port 25b is connected to the port 24b, and the port 25d is connected to the oil path R4. In the speed increasing flow control valve 25, when the signal pressure input to the port 25a becomes high and the signal pressure input to the port 25b becomes low, the spool 25s operates upward in FIG. 25c communicates with the port 25d. That is, the pressure oil in the oil passage R1 can be supplied to the oil passage R4. On the other hand, in the acceleration flow control valve 25, when the signal pressure input to the port 25a becomes low and the signal pressure input to the port 25b becomes high, the spool 25s is moved to the lower side in FIG. And the port 25d is shut off.

  The deceleration flow control valve 26 has ports 26a, 26b, 26c, 26d and a spool 26s. The port 26a is connected to the output port 24b, the port 26c is connected to the oil passage R4, the port 26d is connected to the oil pan 27, and the port 26b is connected to the output port 23b. In the deceleration flow control valve 26, when the signal pressure input to the port 26a becomes high and the signal pressure input to the port 26b becomes low, the spool 26s operates upward in FIG. The port 26c and the port 26d are communicated. That is, the pressure oil in the oil passage R4 is discharged to the oil pan 27. In contrast, in the deceleration flow control valve 26, when the signal pressure input to the port 26a becomes low and the signal pressure input to the port 26b becomes high, the spool 26s moves downward in FIG. The port 26d is shut off.

  Next, the configuration of the oil passage and the mechanism provided between the hydraulic chamber 1c and the oil passage R4 will be described with reference to FIGS. An oil passage 13 connected to the hydraulic chamber 1c is formed in the movable sheave 1b. A hole 70 is formed in the primary shaft 15 in a direction along the axis, and a cylindrical member 71 is attached to the hole 70. Yes. An oil passage 7 is formed in the cylindrical member 71. This oil passage 7 is connected to the oil passage 13. On the other hand, an end cover 9 that closes the opening of the casing 8 is fixed, and an oil passage 51 is formed in the end cover 9. The oil passage 51 is connected to the oil passage R4. A check valve 6 is provided in the hole 70 of the primary shaft 15. The check valve 6 generates a force that presses the piston 14 in a predetermined direction, a piston 14 that is operatively disposed in the hole 70, a valve body 6a that is connected to the piston 14 with a claw 52 interposed therebetween, and the like. The hydraulic chamber 16, a return spring 53 that generates a force that pushes the piston 16 in a direction opposite to the force of the hydraulic chamber 16, a cylindrical member 71 inserted into the hole 70, and a direction along the axis of the cylindrical member 71 And a valve seat 7a formed at the end. Further, an oil passage 54 is formed in the piston 14, and the oil passage 7 and the oil passage 51 can be connected and disconnected. The hydraulic pressure in the hydraulic chamber 16 causes the piston 14 to be pressed to generate a force in the direction in which the valve body 6a is pressed against the valve seat 7a. In contrast, the elastic force of the return spring 53 causes a force in a direction to separate the valve body 6a from the valve seat 7a.

  The hydraulic chamber 16 is connected to the oil passage R3 via an oil passage 17, and a pressure control valve 28 for controlling the hydraulic pressure of the hydraulic chamber 16 is provided. When the hydraulic pressure in the hydraulic chamber 16 increases, the force applied to the piston 14 increases, and when the hydraulic pressure in the hydraulic chamber 16 decreases, the force applied to the piston 14 decreases. The piston 14 and the valve body 6a are configured to operate integrally, the hydraulic pressure in the hydraulic chamber 16 increases, the piston 14 operates toward the left side in FIG. 4, and the valve body 6a is pressed against the valve seat 7a. Then, the check valve 6 is closed. That is, the oil passage 7 and the oil passage R4 are blocked, and the pressure oil is confined in the hydraulic chamber 1c. On the other hand, when the hydraulic pressure in the hydraulic chamber 16 decreases, the valve body 6a is pushed by the hydraulic pressure in the hydraulic chamber 1c and the force of the return spring 54, and the piston 14 moves to the left in FIG. It leaves | separates from the valve seat 7a. Thus, when the check valve 6 is opened, the oil passage 7 and the oil passage R4 are connected, so that the pressure oil is supplied to the hydraulic chamber 1c or discharged from the hydraulic chamber 1c. Is possible. The check valve 6 is provided on the primary shaft 15, and the pressure oil supply and discharge path is longer than the length from the acceleration flow control valve 25 and the deceleration flow control valve 26 to the hydraulic chamber 1c. The length from the check valve 6 to the hydraulic chamber 1c is shorter.

  Next, a control system for controlling the vehicle will be described. The vehicle is provided with an electronic control unit (not shown), and the electronic control unit includes engine speed, vehicle speed, acceleration request (accelerator operation state), braking request (brake pedal operation state), Sensor and switch signals for detecting the input rotation speed and output rotation speed of the belt-type continuously variable transmission, shift position, and the like are input. In this electronic control unit, a signal for controlling the output of the engine, a signal for controlling the gear ratio and torque capacity of the belt-type continuously variable transmission based on the input signal, data and map stored in advance, and the like. Is output.

  In the above vehicle, the engine torque is transmitted to the wheels via the belt type continuously variable transmission, and a driving force is generated. The control of the vehicle will be described. First, the required driving force of the vehicle is determined based on the vehicle speed and the accelerator pedal operation state (accelerator opening), and the required power to be borne by the engine is determined based on the required driving force. Desired. When controlling the engine output based on the required power, a map that defines the target engine speed and the target engine torque is stored in the electronic control unit so that the engine output is in line with the optimum fuel consumption line. . Then, by controlling the gear ratio of the belt type continuously variable transmission, control is performed so that the actual engine speed approaches the target engine speed. In parallel with this, the actual engine torque is controlled to be close to the target engine torque by controlling the opening degree of the electronic throttle valve.

  A control example of the gear ratio of the belt type continuously variable transmission will be described. First, a case will be described in which the accelerator pedal depression amount is reduced and the condition for reducing the gear ratio of the belt-type continuously variable transmission is satisfied. In this case, by controlling the signal pressure output from the speed increasing solenoid valve 23 and the speed reducing solenoid valve 24, the port 25c and the port 25d of the speed increasing flow control valve 25 are communicated with each other and the speed reducing speed is reduced. The port 26d of the industrial flow control valve 26 is shut off. By this control, the pressure oil discharged from the oil pump 18 is supplied to the oil passage R4 via the oil passage R1. Further, the hydraulic pressure in the hydraulic chamber 16 is lowered, the valve body 6a is separated from the valve seat 7a, and the check valve 6 is opened. In this way, when the check valve 6 is opened, the pressure oil in the oil passage R4 is supplied to the hydraulic chamber 1c via the oil passage 51, the oil passage 7 and the oil passage 13, and is moved by the hydraulic pressure in the hydraulic chamber 1c. The thrust that presses the sheave 1b toward the fixed sheave 1a increases. For this reason, a shift in which the winding radius of the belt 3 in the primary pulley 1 is increased, that is, an upshift is performed.

  In contrast, a case will be described in which the accelerator pedal depression amount is increased and the condition for increasing the gear ratio of the belt-type continuously variable transmission is satisfied. In this case, by controlling the signal pressure output from the speed increasing solenoid valve 23 and the speed reducing solenoid valve 24, the port 25d of the speed increasing flow control valve 25 is blocked, and the speed reducing flow control valve 26 ports 26d and 26c communicate with each other. Further, as in the case of the upshift, the check valve 6 is opened. Then, due to the tension of the belt 3, a thrust force that separates the movable sheave 1b from the fixed sheave 1a is generated, and the hydraulic pressure in the hydraulic chamber 1c increases. For this reason, the pressure oil in the hydraulic chamber 1 c is discharged to the oil pan 27 via the oil passage 13, the oil passage 7, the oil passage R 4, and the deceleration flow control valve 26. As a result, a shift, i.e., a downshift, in which the winding radius of the belt 3 in the primary pulley 1 is reduced is performed.

  Next, a case will be described in which the accelerator pedal depression amount is kept constant, and the condition for maintaining the constant gear ratio of the belt-type continuously variable transmission is satisfied. In this case, when the hydraulic pressure in the hydraulic chamber 16 is increased and the check valve 6 is closed, the pressure oil in the hydraulic chamber 1c is not discharged to the oil passage R4, and the pressure oil is supplied to the oil passage 1c. Nor. Thus, when the amount of pressure oil in the hydraulic chamber 1c is kept constant, the winding radius of the belt 3 in the primary pulley 1 is kept constant, and the gear ratio of the belt-type continuously variable transmission is kept constant. Is done. In order to keep the speed ratio of the belt-type continuously variable transmission constant, the amount of pressure oil in the hydraulic chamber 1c may be made constant by opening the check valve 6 and closing the port 25d and the port 26c. Although it is possible, since the check valve 6 is closer to the hydraulic chamber 1c than the acceleration flow control valve 25 and the deceleration flow control valve 26, the amount of leakage of pressure oil is smaller when the check valve 6 is closed. Thus, there is an advantage that the control accuracy of the gear ratio is high. The torque capacity of the belt-type continuously variable transmission is controlled in parallel with the control of the transmission ratio of the belt-type continuously variable transmission and the control of the engine torque as described above. This is performed by controlling the hydraulic pressure in the hydraulic chamber of the secondary pulley 2, and the hydraulic pressure of the secondary pulley 2 increases as the engine torque increases relatively or as the gear ratio of the belt-type continuously variable transmission increases. The chamber hydraulic pressure is increased. As a result, the tension of the belt 3 increases and the torque capacity increases.

  Next, an example of control that can be executed when control for fixing the gear ratio is performed by the belt type continuously variable transmission will be described with reference to the flowchart of FIG. The flowchart of FIG. 1 corresponds to the invention of claim 1. First, it is determined whether or not hydraulic sealing control is being executed (step S1). The hydraulic sealing control is control for closing the check valve 6 and keeping the pressure oil amount in the hydraulic chamber 1c constant. If a negative determination is made in step S1, the control routine of FIG. 1 is terminated. On the other hand, if an affirmative determination is made in step S1, it is determined whether or not the minute accelerator is depressed (step S2). This is to determine whether moderate acceleration or rapid acceleration is required from the accelerator opening. If the accelerator opening is not increasing at the time of determination in step S2 or if the accelerator opening is increasing rapidly, a negative determination is made in step S2 and the control routine is terminated.

  On the other hand, when the minute accelerator is depressed at the time of determination in step S2, that is, when moderate acceleration is required, the determination is positive in step S2. Then, the increase in the required driving force due to the increase in the accelerator opening is covered by increasing the engine torque, and the control for fixing the speed ratio of the belt type continuously variable transmission is continued. In parallel with the control for increasing the engine torque, the control for increasing the torque capacity of the belt type continuously variable transmission is performed. Specifically, control for increasing the hydraulic pressure in the hydraulic chamber of the secondary pulley 2 is performed, and the clamping pressure applied from the secondary pulley 2 to the belt 3 increases. As a result, the tension of the belt 3 is increased and the torque capacity of the belt type continuously variable transmission is increased.

  Subsequent to step S2, it is determined whether or not a downshift has occurred in spite of the fact that control for fixing the gear ratio is continued in the belt type continuously variable transmission (step S3). The reason for making the determination in step S3 will be described. When the tension of the belt 3 is increased as described above, the force with which the belt 3 tries to bite inward in the radial direction by the primary pulley 1 increases. Due to the biting force of the belt 3, a force in the axial direction is generated in a direction in which the movable sheave 1b is separated from the fixed sheave 1a. The movable sheave 1b is pressed toward the left side in FIG. 4 by this axial force. However, since the pressure oil in the hydraulic chamber 1c is an incompressible fluid, the movable sheave 1b operates toward the left side in FIG. Never do. That is, since the gear ratio of the belt type continuously variable transmission is maintained in a fixed state, a negative determination is made in step S3 and the control routine is terminated.

  On the other hand, if air is mixed in the hydraulic chamber 1c, the air is a compressible fluid, so the air is compressed by the force applied to the movable sheave 1b, and the movable sheave 1b is moved to the left in FIG. Operates towards. As a result, the wrapping radius of the belt 3 in the primary pulley 2 is reduced, and a shift in which the transmission ratio of the belt-type continuously variable transmission is increased, that is, a downshift occurs, and a positive determination is made in step S3. As described above, when the tension of the belt 3 is increased by increasing the engine torque while the control for fixing the gear ratio is continued in the belt type continuously variable transmission, the movable pulley 1b is pressed by the tension. By the operation of the movable pulley 1b, the air in the hydraulic chamber 1c is compressed and a downshift occurs. Due to the occurrence of this downshift, the hydraulic sealing control is continued even if the determination in step S3 is affirmative. Then, it is determined whether or not the accelerator pedal is returned, that is, whether or not the accelerator opening is decreased (step S4). The amount of decrease in the accelerator opening determined in step S4 may be the same as the minute increase in the accelerator opening used in the determination in step S2, or may be smaller than that. If a negative determination is made in step S4, the determination in step S4 is repeated. If the determination in step S4 is affirmative, the increased engine torque is reduced as described above, and the hydraulic pressure in the hydraulic chamber of the secondary pulley 2 is reduced in order to reduce the torque capacity of the belt 3.

  Then, it is determined whether or not an upshift has occurred in the belt type continuously variable transmission with the check valve 6 kept closed (step S5). The technical meaning of the process in step S5 will be described. As described above, when the hydraulic pressure in the hydraulic chamber of the secondary pulley is reduced and the tension of the belt 3 is reduced, the force pressing the movable sheave 1b of the primary pulley 1 toward the left side in FIG. 4 is reduced. At this time, if there is no oil leakage in the hydraulic chamber 1c, the force for compressing the air in the hydraulic chamber 1c is weakened, the air volume is restored, and the movable sheave 1b operates toward the right side in FIG. . As a result, a shift that reduces the gear ratio of the belt-type continuously variable transmission, that is, an upshift occurs, and an affirmative determination is made in step S5.

  On the other hand, when the tension of the belt 3 decreases and the force pressing the movable sheave 1b of the primary pulley 1 toward the left side in FIG. 4 decreases, if oil leakage occurs in the hydraulic chamber 1c, Even if the force for compressing the air in the chamber 1c is weakened, the movable sheave 1b does not operate toward the right side in FIG. 4 and no upshift occurs, so a negative determination is made in step S5. As described above, when a negative determination is made in step S5, more specifically, the movable piece 1b further operates toward the left side in FIG. 4 due to the pressure oil leakage in the hydraulic chamber 1c, and a downshift occurs. In this case, the hydraulic sealing control is executed again (step S6), and this control routine is terminated. The processing in step S6 will be described in detail. The closed check valve 6 is once opened, and the oil discharged from the oil pump 18 passes through the oil path R4, the oil path 7, and the oil path 13. Is supplied to the hydraulic chamber 1c, and then the check valve 6 is closed.

  As described above, when the control for fixing the transmission gear ratio of the belt-type continuously variable transmission is being executed, a gentle acceleration request is generated to increase the engine torque, and the control to increase the tension of the belt 3 is executed. Even when the air in the hydraulic chamber 1c is compressed due to the increase in the tension of the belt 3 and a downshift occurs in the belt-type continuously variable transmission, the control for keeping the check valve 6 closed is continued. Therefore, it is possible to prevent erroneous determination that an oil leak has occurred although no oil leak has occurred in the hydraulic chamber 1c. On the other hand, when the upshift is not performed even though the accelerator pedal is returned and the engine torque is reduced, it is determined that an oil leak has occurred in the hydraulic chamber 1c, and the hydraulic sealing control is performed. Try again. According to the control example of FIG. 1, it is not frequently repeated to cancel the hydraulic sealing control and execute again, so that the fuel efficiency of the engine is improved. Further, since the gear ratio of the belt type continuously variable transmission is frequently changed, that is, the busy shift is reduced, drivability is improved.

  Here, the correspondence relationship between the functional means shown in the flowchart of FIG. 1 and the configuration of the invention of claim 1 will be described. Step S2 corresponds to the stepping amount judging means of the present invention, and step S3 is The routine that corresponds to the shift determination means of the present invention and continues the sealing control when the determination is affirmative in step S3 corresponds to the continuation means of the present invention, and step S4 is the pressure oil leakage determination of the present invention. Step S5 corresponds to the re-blocking means of the present invention. The primary pulley 1 corresponds to the first pulley of the present invention, the secondary pulley 2 corresponds to the second pulley of the present invention, the movable sheave 1b corresponds to the movable piece of the present invention, and the fixed sheave 1a The hydraulic chamber 1c corresponds to the first hydraulic chamber of the present invention, the oil passage 7 and the oil passage 54 correspond to the oil passage of the present invention, and the check valve 6 corresponds to the fixed piece of the present invention. This corresponds to the flow control valve of the invention.

  Next, another control example will be described based on the flowchart of FIG. The control of FIG. 5 is a subroutine used in combination with the control of FIG. 1 or a routine executed in parallel, and corresponds to the invention of claim 2. In FIG. 5, steps that perform the same processing as in FIG. 1 are given the same step numbers as in FIG. 1. In FIG. 5, when a positive determination is made in step S4, the process proceeds to step S5 in FIG. On the other hand, if a negative determination is made in step S4 in FIG. 5, has a predetermined time previously stored in the electronic control unit elapsed since the time when the downshift was started in the belt type continuously variable transmission? It is determined whether or not (step S10). If a negative determination is made in step S10, the process returns to step S4.

  On the other hand, if the determination in step S10 is affirmative, in order to minimize the speed ratio of the belt type continuously variable transmission, the speed increasing solenoid valve 23 (DS1) is driven to pressurize the oil path R4 with pressure oil. (Step S11), then the check valve 6 is opened (DS3 drive), the pressure oil in the oil passage R4 is supplied to the hydraulic chamber 1c via the oil passage 7, and an upshift is performed (step S12). ). Then, it is determined whether or not the speed ratio of the belt type continuously variable transmission has become the minimum (highest) (step S13). If a negative determination is made in step S13, the process returns to step S11. On the other hand, if a positive determination is made in step S13, the control routine is terminated via step S6.

  Thus, if a predetermined time has elapsed after a negative determination in step S4 and a positive determination is made in step S10, the gear ratio at the time when the downshift is performed in the belt-type continuously variable transmission is continued. Thus, it is estimated that the fuel consumption deteriorates, that is, the fuel consumption increases, after a long period of time when the engine operating state deviates from the optimum fuel consumption line. As a situation in which a negative determination is made in step S4 and a positive determination is made in step S10, for example, when the vehicle travels on a highway, the accelerator opening is constant after accelerating gently. The situation where the vehicle travels constantly is maintained. That is, such a situation occurs when the road surface resistance and the engine torque are balanced after the accelerator opening is slightly increased.

  Therefore, in the control example of FIG. 5, if a positive determination is made in step S10, an upshift is performed so as to minimize the speed ratio of the belt type continuously variable transmission even if the accelerator pedal is not returned. . Therefore, the fuel consumption of the engine can be improved. In addition, since the upshift is executed after a predetermined time has elapsed, the hydraulic sealing control can be executed again without experiencing a busy shift in which the gear ratio of the belt-type continuously variable transmission is frequently switched. In addition, since the pressure oil is first supplied to the oil passage R4 in step S11 and the check valve 6 is opened in step S12, the pressure oil in the hydraulic chamber 1c passes through the oil passage 7 from the hydraulic chamber 1c. It is possible to prevent the downshift from occurring in the belt type continuously variable transmission.

  Here, the correspondence between the functional means shown in FIG. 5 and the configuration of the invention of claim 2 will be described. Step S2 corresponds to the stepping amount judging means in the present invention, and step S3 is the present invention. The routine that corresponds to the shift determination means, the routine in which the encapsulation control is continued even if an affirmative determination is made in step S3 corresponds to the continuation means of the present invention, and step S10 corresponds to the elapsed time determination means of the present invention. S11 and S12 correspond to the gear ratio control means of the present invention.

  Further, an example of a subroutine that can be executed in combination with the control of FIG. 1 or that can be executed in parallel with the control of FIG. 1 will be described with reference to the flowchart of FIG. The control example of FIG. 6 corresponds to the invention of claim 3. In the flowchart of FIG. 6, steps that perform the same processes as the processes of FIGS. 1 and 5 are given the same step numbers as those of FIGS. 1 and 5. In the flowchart of FIG. 6, when a negative determination is made in step S1, the control routine is terminated, and when a positive determination is made in step S1, the process proceeds to step S2. If an affirmative determination is made in step S2, it is determined whether or not the downshift of the belt type continuously variable transmission due to an increase in engine torque and an increase in belt 3 tension is the second time (step S20).

  If a negative determination is made in step S20, the control routine of FIG. 6 is terminated. On the other hand, the process proceeds to step S5 in the flowchart of FIG. 1, and the determination is affirmative in step S5 and the control is terminated. Then, a positive determination is made in step S20 of FIG. A positive determination in step S20 is considered to be a driver that tends to step on the accelerator pedal as compared with a driver that tends to positively determine in step S10 of FIG. Since it is also determined whether or not there is no pressure oil leakage in step S5 of FIG. 1 which is the premise of the control of FIG. 6, if the determination in step S20 is affirmative, the predetermined explanation described in step S10 above. Without waiting for the passage of time, the necessary Pri pressure, which is the hydraulic pressure supplied to the hydraulic chamber 1c of the primary pulley 1, is obtained (step S21).

  The process of step S21 will be specifically described. First, the maximum engine torque corresponding to the case where the accelerator opening is fully opened is obtained. It is assumed that the maximum engine torque is transmitted to the belt type continuously variable transmission and the speed ratio of the belt type continuously variable transmission is minimized, and is given to the movable sheave 1b to satisfy the speed ratio at that time. A ratio between the thrust and the thrust applied to the movable sheave 2b of the secondary pulley 2 in order to satisfy the torque capacity necessary for transmitting the maximum engine torque is obtained. Next, the necessary Pri pressure is calculated as the hydraulic pressure to be supplied to the hydraulic chamber 1c from the thrust ratio. In order to perform the process of step S21, the electronic control unit 103 stores in advance a map used when calculating the necessary Pri pressure. As the parameters of this map, the torque input to the belt type continuously variable transmission, the input rotational speed and output rotational speed of the belt type continuously variable transmission, and the safety factor are used. The safety factor is a safety factor for avoiding the slip of the belt 3, and a safety factor obtained by experiment or simulation is used.

  Following this step S21, the speed increasing solenoid valve (DS1) 23 is driven with the required Pri pressure as a target, and the pressure oil discharged from the oil pump 18 is supplied to the oil passage R4 (step S22), and the process goes to step S12. move on. By the process of step S12, an upshift is performed in which the speed ratio of the belt type continuously variable transmission is reduced. Then, it is determined whether or not the gear ratio of the belt type continuously variable transmission has become minimum (step S13). If a negative determination is made in step S13, the process returns to step S22. On the other hand, if an affirmative determination is made in step S13, the process proceeds to step S6, and the gear ratio of the belt type continuously variable transmission is fixed to the minimum value.

  When the control shown in FIG. 6 is executed, when the hydraulic sealing control for fixing the gear ratio is executed in the belt-type continuously variable transmission, the accelerator pedal is depressed slightly, and the tension of the belt 3 is increased. As a result, when the downshift is performed twice in the belt type continuously variable transmission, an upshift that minimizes the speed ratio of the belt type continuously variable transmission is performed even if the predetermined time does not elapse. Therefore, the time during which the engine operating point deviates from the optimum fuel consumption line can be relatively shortened, and the fuel efficiency of the engine is improved.

  In the control example of FIG. 6, when the downshift occurs twice in the belt type continuously variable transmission and the determination in step S20 is affirmative, the process proceeds to step S6, and the speed ratio of the belt type continuously variable transmission is minimized. Since the hydraulic sealing control is performed so as to be fixed to the hydraulic pressure, the power loss of the oil pump 18 can be eliminated without supplying the hydraulic oil to the hydraulic chamber 1c each time the gentle acceleration operation is repeated. . Further, when the process proceeds to step S12 via step S22, the hydraulic pressure in the hydraulic chamber 1c is temporarily increased, so that power loss of the oil pump 18 occurs. Thereafter, the accelerator pedal is stepped on and increased. However, since the downshift does not occur in the belt-type continuously variable transmission during hydraulic sealing control, the engine operating point does not deviate from the optimum fuel consumption line, and the fuel efficiency of the engine is improved.

  Here, the correspondence between the functional means shown in FIGS. 1 and 6 and the configuration of the present invention will be described. Step S2 in FIG. 1 corresponds to the stepping-in amount determining means of the present invention, and FIG. Step S3 corresponds to the first shift determining means of the present invention, and the routine in which affirmative determination is made in step S3 of FIG. 1 to continue the encapsulation control corresponds to the continuation means of the present invention, and the positive is determined in step S5 of FIG. Then, the routine which proceeds to step S20 in FIG. 6 corresponds to the second shift determining means of the present invention, and steps S21, S22 and S6 in FIG. 6 correspond to the re-blocking means of the present invention.

It is a flowchart which shows an example of the control performed with the belt-type continuously variable transmission of this invention. 1 is a schematic diagram of a belt type continuously variable transmission according to the present invention. FIG. 3 is a cross-sectional view showing a configuration of a primary pulley of the belt type continuously variable transmission shown in FIG. 2. FIG. 3 is a schematic diagram showing a configuration of a primary pulley and a hydraulic circuit of the belt type continuously variable transmission shown in FIG. 2. It is a flowchart which shows the other example of control performed combining with the example of control of FIG. 6 is a flowchart showing still another control example executed in combination with the control example of FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Primary pulley, 1a ... Fixed sheave, 1b ... Movable sheave, 1c ... Hydraulic chamber, 2 ... Secondary pulley, 3 ... Belt, 6 ... Check valve, 7,54 ... Oil path.

Claims (3)

The first pulley has a first pulley and a second pulley to which power output from the engine is transmitted and a belt is wound, and the first pulley is movable in a direction along a rotation center line thereof, and A first hydraulic chamber that has a fixed piece that is inoperable in a direction along the rotation center line, and that generates thrust that is supplied with pressure oil to press the fixed piece in a direction along the rotation center line; An oil passage through which the pressure oil supplied to the first hydraulic chamber and the pressure oil discharged from the first hydraulic chamber pass, and a clamping pressure applied to the belt from the second pulley when the pressure oil is supplied are generated. 2 hydraulic chambers are provided, the oil passage is shut off, and the amount of pressure oil held in the first hydraulic chamber is kept constant, and the gear ratio between the first pulley and the second pulley is increased. Control of a belt-type continuously variable transmission having a constant flow control valve In the location,
Depression amount determination means for determining whether or not the accelerator pedal of the vehicle is depressed by a small amount when sealing control is performed to keep the speed ratio constant by blocking the oil passage by the flow rate control valve; ,
The depression amount determining means determines that the accelerator pedal has been depressed by a small amount, increases the engine torque, and controls to increase the hydraulic pressure in the second hydraulic chamber in order to increase the belt tension. When the belt tension increases, the movable piece of the first pulley moves in the direction along the rotation center line, and the air in the first hydraulic chamber is compressed, so that the gear ratio is relatively large. Shift determining means for determining whether or not a shift has occurred;
When it is determined by the shift determining means that a shift has occurred in which the air in the first hydraulic chamber is compressed and the gear ratio becomes relatively large, the oil passage is blocked by the flow control valve and the shift is performed. Continuation means for continuing the encapsulation control to keep the ratio constant;
When the control for maintaining the gear ratio constant is continued by the continuation means, the accelerator pedal is returned to reduce the engine torque, and the hydraulic pressure in the second hydraulic chamber is reduced to Pressure oil leakage that determines whether or not pressure oil leaks in the first hydraulic chamber, depending on whether or not a shift in which the gear ratio becomes relatively small occurs when the belt tension is reduced. Judgment means,
When it is determined by the pressure oil leakage determination means that a pressure oil leak has occurred in the first hydraulic chamber, the oil passage is opened by the flow control valve, and the oil passage passes through the oil passage. Re-blocking means for supplying pressure oil to the first hydraulic chamber and increasing the amount of pressure oil retained in the first hydraulic chamber, and then performing control for blocking the oil passage again by the flow control valve; A control device for a belt-type continuously variable transmission. The first pulley has a first pulley and a second pulley to which power output from the engine is transmitted and a belt is wound, and the first pulley is movable in a direction along a rotation center line thereof, and A first hydraulic chamber that has a fixed piece that is inoperable in a direction along the rotation center line, and that generates thrust that is supplied with pressure oil to press the fixed piece in a direction along the rotation center line; An oil passage through which the pressure oil supplied to the first hydraulic chamber and the pressure oil discharged from the first hydraulic chamber pass, and a clamping pressure applied to the belt from the second pulley when the pressure oil is supplied are generated. 2 hydraulic chambers are provided, the oil passage is shut off, and the amount of pressure oil held in the first hydraulic chamber is kept constant, and the gear ratio between the first pulley and the second pulley is increased. Control of a belt-type continuously variable transmission having a constant flow control valve In the location,
Depression amount determination means for determining whether or not the accelerator pedal of the vehicle is depressed by a small amount when sealing control is performed to keep the speed ratio constant by blocking the oil passage by the flow rate control valve; ,
The depression amount determining means determines that the accelerator pedal has been depressed by a small amount, increases the engine torque, and controls to increase the hydraulic pressure in the second hydraulic chamber in order to increase the belt tension. When the belt tension increases, the movable piece of the first pulley moves in the direction along the rotation center line, and the air in the first hydraulic chamber is compressed, so that the gear ratio is relatively large. Shift determining means for determining whether or not a shift has occurred;
When it is determined by the shift determining means that a shift has occurred in which the air in the first hydraulic chamber is compressed and the gear ratio becomes relatively large, the oil passage is blocked by the flow control valve and the shift is performed. Continuation means for continuing the encapsulation control to keep the ratio constant;
By this continuation means, when the enclosing control for interrupting the oil passage and keeping the speed ratio constant is continued, the time from the time when the speed change where the speed ratio becomes relatively large is started, An elapsed time judging means for judging whether or not a predetermined time has passed;
If it is determined by the elapsed time determination means that the time from the start of the shift at which the gear ratio becomes relatively large has passed a predetermined time, the oil flow control valve The speed ratio is minimized by opening the path and supplying pressure oil to the first hydraulic chamber via the oil path to increase the amount of pressure oil retained in the first hydraulic chamber. A control device for a belt-type continuously variable transmission, comprising: a gear ratio control means for performing control. The first pulley has a first pulley and a second pulley to which power output from the engine is transmitted and a belt is wound, and the first pulley is movable in a direction along a rotation center line thereof, and A first hydraulic chamber that has a fixed piece that is inoperable in a direction along the rotation center line, and that generates thrust that is supplied with pressure oil to press the fixed piece in a direction along the rotation center line; An oil passage through which the pressure oil supplied to the first hydraulic chamber and the pressure oil discharged from the first hydraulic chamber pass, and a clamping pressure applied to the belt from the second pulley when the pressure oil is supplied are generated. 2 hydraulic chambers are provided, the oil passage is shut off, and the amount of pressure oil held in the first hydraulic chamber is kept constant, and the gear ratio between the first pulley and the second pulley is increased. Control of a belt-type continuously variable transmission having a constant flow control valve In the location,
Depression amount determination means for determining whether or not the accelerator pedal of the vehicle is depressed by a small amount when sealing control is performed to keep the speed ratio constant by blocking the oil passage by the flow rate control valve; ,
The depression amount determining means determines that the accelerator pedal has been depressed by a small amount, increases the engine torque, and controls to increase the hydraulic pressure in the second hydraulic chamber in order to increase the belt tension. When the belt tension increases, the movable piece of the first pulley moves in the direction along the rotation center line, and the air in the first hydraulic chamber is compressed, so that the gear ratio is relatively large. First shift determining means for determining whether or not a first shift has occurred;
When it is determined by the shift determining means that a shift has occurred in which the air in the first hydraulic chamber is compressed and the gear ratio becomes relatively large, the oil passage is blocked by the flow control valve and the shift is performed. Continuation means for continuing the encapsulation control to keep the ratio constant;
When the control for maintaining the gear ratio constant is continued by the continuation means, the accelerator pedal is returned to reduce the engine torque, and the hydraulic pressure in the second hydraulic chamber is reduced to When the belt tension is reduced, after the gear ratio becomes relatively small, the accelerator pedal is depressed a little further to increase the engine torque, and the belt tension is increased. Therefore, when control for increasing the hydraulic pressure in the second hydraulic chamber is performed, the movable piece of the first pulley moves in the direction along the rotation center line due to an increase in the tension of the belt. Second shift determining means for determining whether or not a second shift in which the fluid in the hydraulic chamber is compressed and the gear ratio is relatively large has occurred;
When it is determined by the second shift determining means that a second shift in which the gear ratio is relatively large has occurred, the oil passage is opened by the flow control valve, and the oil passage is routed through the oil passage. Then, pressure oil is supplied to the first hydraulic chamber to increase the amount of pressure oil held in the first hydraulic chamber to perform control to minimize the speed ratio, and thereafter, the flow control valve A control device for a belt-type continuously variable transmission, comprising: re-blocking means for performing control to block the oil passage.

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