JP2015148310A - Control device of continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a continuously variable transmission, which suppresses uncomfortable feeling imparted to a driver by suppressing a change of a behavior of a vehicle even if oil vibration is generated in a control valve unit.SOLUTION: A control device of a continuously variable transmission comprises a continuously variable transmission mechanism in which a belt is wound between a primary pulley and a secondary pulley, and a torque converter which is arranged between an engine and the continuously variable transmission mechanism and has a lockup clutch, and controls a solenoid valve in a control valve, creates signal pressure from pilot pressure which is pressure-regulated so as to reach prescribed pressure with line pressure as original pressure, controls a change gear ratio of the continuously variable transmission mechanism according to a traveling state of a vehicle, and controls a fastened state of the lockup clutch. When the line pressure which is set according to the traveling state is not higher than the prescribed pressure in a first traveling state in which a tire rotation primary frequency coincides with an oil vibration frequency of the control valve, the control means raises the line pressure so as to exceed the prescribed pressure.

Description

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

  Conventionally, Patent Document 1 discloses a technique for realizing a target gear ratio while preventing belt slip from occurring using a minimum necessary pulley shaft thrust.

JP 2000-18347 A

However, even if belt slip does not occur, if oil vibration occurs in the control valve unit, the behavior of the vehicle may change due to the vibration, which may cause the driver to feel uncomfortable.
The present invention has been made paying attention to the above-described problem, and is capable of continuously changing the behavior of the vehicle by suppressing a change in the behavior of the vehicle even when oil vibration occurs in the control valve unit. It is an object of the present invention to provide a control device for a machine.

  In order to achieve the above object, in a continuously variable transmission control device according to the present invention, a continuously variable transmission mechanism in which a belt is wound between a primary pulley and a secondary pulley to transmit power to a tire, an engine, and the continuously variable transmission. A signal pressure is obtained from the pilot pressure that is adjusted between the torque converter having a lock-up clutch and the solenoid valve in the control valve so that the line pressure becomes the original pressure. And a control means for controlling the gear ratio of the continuously variable transmission mechanism and controlling the engagement state of the lock-up clutch according to the traveling state of the vehicle. In the first running state in which the primary rotational frequency of the tire and the oil vibration frequency of the control valve coincide with each other, the control means responds to the running state. When the line pressure set in the above is equal to or lower than the predetermined pressure, the line pressure is increased to be higher than the predetermined pressure.

  Therefore, in normal line pressure control, even when the line pressure is lower than the predetermined pressure and the pilot pressure is the same as the line pressure, the primary rotational frequency of the tire and the oil pressure of the control valve are controlled. Since the line pressure becomes higher than the predetermined pressure in the first traveling state in which the frequency matches, the line pressure can be made higher than the pilot pressure. For this reason, even if oil vibrations occur in the line pressure, the influence on the pilot pressure is reduced, the elements that vibrate in the control valve are reduced, and the mutual vibrations are suppressed from being amplified. it can. Thereby, even if the rotation primary frequency of a tire and the oil vibration frequency of a control valve correspond, resonance with an oil vibration frequency and a tire primary frequency can be controlled. Therefore, it is possible to suppress the driver from feeling uncomfortable due to vehicle behavior fluctuations or the like.

1 is a system diagram illustrating a control device for a continuously variable transmission according to a first embodiment. FIG. FIG. 2 is a hydraulic circuit diagram schematically illustrating the inside of a control valve unit according to the first embodiment. FIG. 6 is a characteristic diagram illustrating a relationship among line pressure, pilot pressure, and lockup pressure in the continuously variable transmission according to the first embodiment. 6 is a time chart when the lockup clutch is engaged in a state where oil vibration has occurred with the line pressure being lower than a first predetermined pressure. 3 is a flowchart illustrating line pressure increase control according to the first embodiment.

  FIG. 1 is a system diagram illustrating a control device for a continuously variable transmission according to a first embodiment. The vehicle according to the first embodiment includes an engine 1 that is an internal combustion engine and a continuously variable transmission, and transmits a driving force to a tire 8 that is a drive wheel via a differential gear. A power transmission path connected from the belt type continuously variable transmission mechanism CVT to the tire 8 is collectively referred to as a power train PT.

  The continuously variable transmission includes a torque converter 2, an oil pump 3, a forward / reverse switching mechanism 4, and a belt type continuously variable transmission mechanism CVT. The torque converter 2 is connected to the engine 1 and connected to the pump impeller 20 that rotates integrally with the drive claw that drives the oil pump 3 and the input side of the forward / reverse switching mechanism 4 (the input shaft of the belt-type continuously variable transmission mechanism CVT). A turbine runner 21, and a lockup clutch 2a capable of integrally connecting the pump impeller 20 and the turbine runner 21. The forward / reverse switching mechanism 4 includes a planetary gear mechanism and a plurality of clutches 4a, and switches between forward and reverse depending on the engagement state of the clutch 4a. The belt type continuously variable transmission mechanism CVT includes a primary pulley 5 connected to the output side of the forward / reverse switching mechanism 4 (input shaft of the continuously variable transmission), a secondary pulley 6 that rotates integrally with the drive wheels, and a primary pulley 5 And a belt 7 wound between the secondary pulley 6 and transmitting power, and a control valve unit 20 for supplying a control pressure to each hydraulic actuator.

  The control unit 10 includes a range position signal from the shift lever 11 that selects the range position by the driver's operation (hereinafter, the range position signal is described as P range, R range, N range, and D range, respectively), and an accelerator. The accelerator pedal opening signal (hereinafter referred to as APO) from the pedal opening sensor 12, the primary rotation speed signal Npri from the primary pulley rotation speed sensor 13 for detecting the rotation speed of the primary pulley 5, and the rotation speed of the secondary pulley 6 The secondary rotational speed signal Nsec from the secondary pulley rotational speed sensor 14 to be detected and the engine rotational speed Ne from the engine rotational speed sensor 15 to detect the engine rotational speed are read. In the case of the D range, the primary rotational speed signal Npri coincides with the turbine rotational speed when the clutch 4a is engaged, and is also referred to as the turbine rotational speed Nt hereinafter.

  The control unit 10 controls the engaged state of the clutch 4a according to the range position signal. Specifically, in the P range or N range, the clutch 4a is released, and in the R range, a control signal is output to the control valve unit 20 so that the forward / reverse switching mechanism 4 outputs reverse rotation, and the reverse clutch (Or brake). In the D range, a control signal is output to the control valve unit 20 so that the forward / reverse switching mechanism 4 integrally rotates and outputs a normal rotation, and the forward clutch 4a is engaged. Further, the vehicle speed VSP is calculated based on the secondary rotation speed Nsec.

  In the control unit 10, there is set a shift map that can achieve an optimum fuel consumption state according to the running state. A target gear ratio (corresponding to a predetermined gear ratio) is set based on the APO signal and the vehicle speed VSP on the basis of this shift map. Then, the feedforward control is performed based on the target speed ratio, and the actual speed ratio is detected based on the primary speed signal Npri and the secondary speed signal Nsec, and the set target speed ratio and the actual speed ratio are determined. Feedback control to match. Based on this control, a hydraulic pressure command for each pulley and an engagement pressure command for the lock-up clutch 2a are output to the control valve unit 20, and each pulley hydraulic pressure and a lock-up differential pressure for the lock-up clutch 2a are controlled. In the first embodiment, no particular pressure sensor or the like is provided in the control valve unit 20, and when the line pressure is detected, the line pressure is detected from a command signal to the line pressure solenoid valve 30 described later.

  FIG. 2 is a hydraulic circuit diagram schematically illustrating the inside of the control valve unit according to the first embodiment. The pump pressure discharged from the oil pump 3 driven by the engine 1 is discharged to the oil passage 401 and adjusted to the line pressure by the pressure regulator valve 21. The oil passage 401 is supplied to each pulley as an original pressure of each pulley hydraulic pressure. A pilot valve 25 is provided in the oil passage 402 branched from the oil passage 401, and a first predetermined pressure (corresponding to the predetermined pressure in claim 1) set in advance is generated from the line pressure to generate a pilot pressure oil passage 403. Output. Thereby, the original pressure of the signal pressure output from the solenoid valve mentioned later is generated. When the line pressure is equal to or lower than the first predetermined pressure, the line pressure and the pilot pressure are output as the same pressure.

  An oil passage 404 is connected to the pressure regulator valve 21, and the pressure is adjusted to the engagement pressure of the clutch 4a by the clutch regulator valve 22. A torque converter regulator valve 23 is connected to the oil passage 405, and is regulated to the converter pressure of the torque converter 2 by the torque converter regulator valve 23. A lockup valve 24 is connected to an oil passage 406 branched from the oil passage 405, and the lockup valve 24 regulates the lockup pressure of the lockup clutch 2a. The lockup clutch 2a is subjected to lockup control by a lockup differential pressure that is a differential pressure between the converter pressure and the lockup pressure. Thus, by providing the clutch regulator valve 22 downstream of the pressure regulator valve 21 and further providing the torque converter regulator valve 23 downstream, even if excessive torque is input from the engine 1, slipping of the lockup clutch 2a The slippage of the clutch 4a prevents the belt-type continuously variable transmission mechanism CVT from slipping.

  The pilot pressure oil passage 403 includes a line pressure solenoid valve 30 that controls the line pressure, a clutch pressure solenoid valve 31 that controls the clutch engagement pressure, and a lockup solenoid valve 32 that controls the lockup pressure. Each solenoid valve controls the energization state of the solenoid based on the control signal transmitted from the control unit 10, supplies the signal pressure to each valve using the pilot pressure as the original pressure, and controls the pressure regulation state of each valve.

  Here, a problem when oil vibration occurs in the control valve unit 20 will be described. As described above, various valves are provided in the control valve unit 20. The pressure regulator valve 21 is a valve that regulates the highest hydraulic pressure discharged from the oil pump 3, and is therefore easily affected by pump pulsation.The spool that constitutes the pressure regulator valve 21 is designed with a valve diameter, inertia, etc. It may vibrate according to the specifications and the line pressure may vibrate (hereinafter referred to as oil vibration). Also, since the line pressure is set according to the accelerator pedal opening APO, the line pressure is set low when the accelerator pedal opening APO is small, and the line pressure is set high when the accelerator pedal opening APO is large. .

  FIG. 3 is a characteristic diagram showing the relationship among the line pressure, the pilot pressure, and the lockup pressure in the continuously variable transmission according to the first embodiment. The horizontal axis represents the line pressure, and the vertical axis represents the oil pressure. The line pressure has a linear relationship. The slip lock-up control of the lock-up clutch 2a is controlled by a lock-up differential pressure (= converter pressure-lock-up pressure) that is a differential pressure between the converter pressure and the lock-up pressure. This will be described based on the regulated lock-up pressure. As described in the hydraulic circuit configuration of FIG. 2, the pilot pressure is a hydraulic pressure adjusted using the line pressure as a source pressure, and the lockup pressure is a hydraulic pressure adjusted downstream of the line pressure. In the region where the line pressure is higher than the first predetermined pressure, the line pressure> the pilot pressure> the lockup pressure. Even if oil vibrations occur in the line pressure, the pilot pressure is less affected, and the signal pressure output from the lockup solenoid valve 32 is less affected. Therefore, there are few elements which vibrate within the control valve, and as a result, the oil vibration is not increased by mutual interference within the control valve.

  On the other hand, in a region where the line pressure is equal to or lower than the first predetermined pressure, line pressure = pilot pressure> lockup pressure. At this time, if oil vibration occurs in the line pressure, the pilot pressure also vibrates together. Further, since the converter pressure is lower than the line pressure, the converter pressure itself is not affected, but the lockup solenoid valve 32 that regulates the converter pressure to the lockup pressure is affected by the oscillating pilot pressure. Therefore, the signal pressure discharged from the lockup solenoid valve 32 is also influenced by the vibration of the pilot pressure, and is affected by oil vibration when controlling the lockup pressure. As described above, when oil vibration occurs in the line pressure in the region where the line pressure is equal to or lower than the first predetermined pressure, the number of elements that vibrate in the control valve increases, and as a result, the oil vibration increases due to mutual interference in the control valve. End up.

  FIG. 4 is a time chart when oil vibration occurs when the vehicle runs while the lockup clutch is engaged in a state where the line pressure is lower than the first predetermined pressure. In FIG. 4, the thick solid line is the tire rotation primary frequency, the thin solid line is the natural frequency of the power train PT, the thick dotted line is the oil vibration frequency, and the alternate long and short dash line is the power when the belt type continuously variable transmission mechanism CVT is at the highest side. The natural frequency of the train PT and the two-dot chain line represent the natural frequency of the power train PT when the belt type continuously variable transmission mechanism CVT is at the lowest level. Here, the tire rotation primary frequency represents a primary frequency that is easily recognized by the occupant among the rotation vibrations generated when the tire 8 rotates. The natural frequency of the power train PT represents the torsional natural frequency of an elastic system in which the power train PT transmits power to the tire 8 via a shaft or the like. This natural frequency indicates that the belt type continuously variable transmission mechanism CVT changes to the high frequency side if it is high, and changes to the low frequency side if it is low.

  As shown in FIG. 4, the vibration of the line pressure affects the pilot pressure, and the oil vibration frequency (for example, the line pressure frequency) in the control valve, the tire rotation primary frequency, the natural frequency of the power train PT, and the resonance. In some cases, the longitudinal acceleration vibration of the vehicle may be amplified. Therefore, in the first embodiment, the line pressure is increased when the lockup clutch 2a is engaged and the line pressure is equal to or lower than the first predetermined pressure and there is a possibility that resonance of various vibrations may occur.

  As shown in FIG. 4, the intersection of the oil vibration frequency of the line pressure (denoted as CVT oil vibration frequency in FIG. 4) and the natural frequency of the power train PT is x1 (second running state), and the oil vibration frequency. X2 is the intersection of the tire rotation primary frequency and the tire rotation primary frequency, the intersection of the natural frequency of the power train PT and the tire rotation primary frequency is x3 (the third driving state), and the tire rotation primary frequency is the maximum. Let x4 be the intersection with the natural frequency at low and x5 be the intersection between the primary frequency of tire rotation and the natural frequency at the highest. These various frequencies are values determined by respective design specifications (design specifications of the pressure regulator valve, pump characteristics, design specifications of the power train PT, tire diameter, etc.).

As shown in the vibration state of the longitudinal acceleration G in FIG. 4, when the vehicle starts and gradually accelerates, the speed ratio of the belt type continuously variable transmission mechanism CVT is the lowest based on the vehicle speed VSP and the accelerator pedal opening APO. Upshift from high to high. With this upshift, the natural frequency of the power train PT increases, and with the increase of the vehicle speed VSP, the tire rotation primary frequency also increases. Thereafter, the longitudinal acceleration G starts to vibrate due to the influence of oil vibration after the lockup clutch 2a is engaged.
At time t1, in the vicinity of the intersection x1, the natural frequency and the oil vibration frequency of the power train PT are likely to resonate, and longitudinal acceleration vibration is likely to occur.
Further, at time t2, near the intersection x2, the tire rotation primary frequency and the oil vibration frequency are likely to resonate, and the natural frequency of the power train PT is also close to each other.
Further, at time t3, near the intersection point x3, the tire rotation primary frequency and the natural frequency of the power train PT tend to resonate, and there is a possibility that resonance will occur with the oil vibration frequency.

  Therefore, the traveling state having the intersections x1, x2, x3 that induce such resonance is specified by the area of the accelerator pedal opening APO and the vehicle speed VSP, and the accelerator is operated when the lockup clutch 2a is engaged. In the region where the pedal opening APO and the vehicle speed VSP are set, the line pressure is increased to a predetermined pressure higher than the first predetermined pressure. As a result, even if an oil vibration occurs in the line pressure, the line pressure becomes higher than the first predetermined pressure, so that the line pressure can be made higher than the pilot pressure, and the oil vibration is caused by mutual interference in the control valve. Amplification can be eliminated, and resonance with other vibration components can be suppressed. In determining the traveling state based on the accelerator pedal opening APO and the vehicle speed VSP, for example, the traveling state may be determined based on the traveling state including the intersection x4 and the intersection x5. The intersection points x4 and x5 can be determined by design specifications, and can cover all the regions where the natural frequency of the power train PT and the tire rotation primary frequency may resonate. The reason why resonance is caused by the relationship between the oil vibration frequency and the natural frequency of the power train PT and the primary tire rotation frequency is that it can be said that the region includes the intersection points x4 and x5.

FIG. 5 is a flowchart illustrating the line pressure increase control according to the first embodiment.
In step S1, it is determined whether or not the lockup clutch 2a is engaged, and if it is determined that the lockup is being performed, the process proceeds to step S2, otherwise the process proceeds to step S6 and the normal line Perform pressure control. Normal line pressure control is control for setting the line pressure according to the accelerator pedal opening APO or the like.
In step S2, it is determined whether the accelerator pedal opening APO is within a predetermined opening range (APO1 ≦ APO ≦ APO2). If the opening is within the predetermined opening range, the process proceeds to step S3. Otherwise, the process proceeds to step S6. Perform normal line pressure control. This predetermined opening range is set based on the traveling state that is considered to include the intersections x1, x2, and x3.
In step S3, it is determined whether the vehicle speed VSP is within a predetermined vehicle speed range (VSP1 ≦ VSP ≦ VSP2). If the vehicle speed VSP is within the predetermined opening range, the process proceeds to step S4. Take control. The predetermined vehicle speed range is set based on a traveling state that is considered to include the intersections x1, x2, and x3.

In step S4, it is determined whether or not the line pressure is equal to or lower than a first predetermined pressure. If the line pressure is higher than the first predetermined pressure, the process proceeds to step S6 and normal line pressure control is performed. Instead of the first predetermined pressure, a value obtained by subtracting a pressure in consideration of the safety factor from the first predetermined pressure may be used, and there is no particular limitation. The first predetermined pressure is determined in advance according to the design specifications of the pilot valve 25, and the line pressure can be detected from the command signal to the line pressure solenoid 30, so that the command signal to the current line pressure solenoid 30 and Then, it is determined whether the line pressure is equal to or lower than the first predetermined pressure by comparing with a value corresponding to the first predetermined pressure stored in advance.
In step S5, line pressure increase control is performed. Specifically, the line pressure is set to a second predetermined pressure that is higher than the first predetermined pressure. As the second predetermined pressure, a value obtained by adding a third predetermined pressure in consideration of the amplitude of oil vibration obtained in advance through experiments or the like to the first predetermined pressure is used. Thereby, the consumption of energy can be suppressed without excessively increasing the line pressure while further eliminating the influence of the oil vibration on the pilot pressure, but the first predetermined pressure may be used.

  As described above, when the line pressure is lower than the predetermined pilot pressure during the lockup, in the driving state that is considered to include the intersections x1, x2, and x3, the influence of the oil vibration is eliminated by increasing the line pressure. be able to. Thereby, it becomes possible to suppress resonance with the primary frequency of tire rotation and the natural frequency of the power train PT, and a stable fastening state can be maintained. Further, in the present embodiment, the control for suppressing the resonance when the oil vibration frequency in the control valve and the tire rotation primary frequency resonate in the state where the lockup clutch is completely engaged has been described. The present invention can be applied even when the lock-up clutch is released. In this case, it is necessary to set the natural frequency of the power train PT in a state where the lockup clutch is released.

As described above, the effects listed below can be obtained in the embodiment.
(1) A belt type continuously variable transmission mechanism CVT that winds a belt 7 between a primary pulley 5 and a secondary pulley 6 to transmit power to a tire 8;
A torque converter 2 provided between the engine 1 and the belt-type continuously variable transmission mechanism CVT and having a lock-up clutch 2a;
By controlling the solenoid valve in the control valve, the signal pressure is generated from the pilot pressure that is adjusted to be equal to or lower than the first predetermined pressure with the line pressure as the original pressure, and the belt type A control unit 10 (control means) for controlling the gear ratio of the continuously variable transmission mechanism CVT and for controlling the engagement state of the lock-up clutch;
In a continuously variable transmission control device comprising:
The control unit 10 determines that the line pressure set according to the running state is the first predetermined pressure at the intersection x2 where the tire rotational primary frequency and the oil vibration frequency of the control valve coincide (first running state). In the following cases, the line pressure was increased to be higher than the first predetermined pressure.
Therefore, in normal line pressure control, even if the line pressure is lower than the first predetermined pressure and the pilot pressure is the same as the line pressure, the primary rotational frequency of the tire and the control valve Since the line pressure becomes higher than the first predetermined pressure in the first traveling state in which the oil vibration frequency coincides, the line pressure can be made higher than the pilot pressure. For this reason, even if oil vibrations occur in the line pressure, the influence on the pilot pressure is reduced, the elements that vibrate in the control valve are reduced, and the mutual vibrations are suppressed from being amplified. it can. Thereby, even if the rotation primary frequency of a tire and the oil vibration frequency of a control valve correspond, resonance with an oil vibration frequency and a tire primary frequency can be controlled. Therefore, it is possible to suppress the driver from feeling uncomfortable due to vehicle behavior fluctuations or the like.

(2) In the control unit 10, the lock-up clutch 2a is engaged, the oil vibration frequency of the line pressure and the natural frequency of the power train PT (the torsional characteristic between the continuously variable transmission and the tire) When the line pressure is lower than the first predetermined pressure at the intersection x1 where the vibration frequency matches (second running state), the line pressure is increased to be higher than the first predetermined pressure. .
Therefore, even if oil vibration occurs in the line pressure, the pilot pressure is not affected, and the locked state of the lockup clutch 2a can be stably maintained, so that resonance with the natural frequency of the power train PT Can be suppressed. Therefore, it is possible to suppress the driver from feeling uncomfortable with fluctuations in longitudinal acceleration and the like.

(3) When the lock-up clutch 2a is engaged and the control unit 10 is at the intersection x3 where the primary rotational frequency of the tire coincides with the natural frequency of the power train PT (third running state), When the pressure is equal to or lower than the first predetermined pressure, the line pressure is increased to be higher than the first predetermined pressure.
Therefore, even if oil vibration occurs in the line pressure, the pilot pressure is not affected, and the engagement state of the lockup clutch 2a can be stably maintained. Therefore, the primary rotational frequency of the tire and the power train PT Even if the resonance with the natural frequency occurs, the resonance between the resonance and the oil vibration frequency can be suppressed. Therefore, it is possible to suppress the driver from feeling uncomfortable with fluctuations in longitudinal acceleration and the like.

(4) When the accelerator pedal opening APO is within a predetermined opening range including the intersection x2 and the line pressure is equal to or lower than the first predetermined pressure, the control unit 10 sets the line pressure to be higher than the first predetermined pressure. It was decided to raise it to be higher.
Therefore, the running state can be specified with a simple configuration. In addition, not only the intersection point x2, but also a traveling state including the intersection points x1, x3, and further x4, x5 may be specified.

(5) When the vehicle speed VSP is within a predetermined vehicle speed range including the intersection x2, the control unit 10 sets the line pressure higher than the first predetermined pressure when the line pressure is equal to or lower than the first predetermined pressure. It was decided to raise.
Therefore, the running state can be specified with a simple configuration. In addition, not only the intersection point x2, but also a traveling state including the intersection points x1, x3, and further x4, x5 may be specified.

1 engine
2 Torque converter
2a Lock-up clutch
3 Oil pump
4 Forward / reverse switching mechanism
5 Primary pulley
6 Secondary pulley
7 belt
10 Control unit
12 Accelerator pedal opening sensor
13 Primary speed sensor
14 Secondary speed sensor
15 Engine speed sensor

Claims (5)

A continuously variable transmission mechanism that winds a belt between a primary pulley and a secondary pulley to transmit power to the tire;
A torque converter provided between the engine and the continuously variable transmission mechanism and having a lock-up clutch;
A solenoid valve in the control valve is controlled to generate a signal pressure from a pilot pressure adjusted to a predetermined pressure using the line pressure as a source pressure, and according to the running state of the vehicle, the continuously variable transmission mechanism Control means for controlling the gear ratio and controlling the engagement state of the lock-up clutch;
In a continuously variable transmission control device comprising:
In the first running state in which the primary rotational frequency of the tire coincides with the oil vibration frequency of the control valve, the control means has the line pressure set according to the running state equal to or less than the predetermined pressure. In this case, the control device for the continuously variable transmission increases the line pressure so as to be higher than the predetermined pressure. The control device for a continuously variable transmission according to claim 1,
In the control means, the lock-up clutch is in an engaged state, and the oil vibration frequency of the line pressure matches the torsional natural frequency between the continuously variable transmission and the tire. A control device for a continuously variable transmission, wherein when the line pressure is equal to or lower than the predetermined pressure in a running state, the line pressure is increased so as to be higher than the predetermined pressure. The control device for a continuously variable transmission according to claim 1 or 2,
The control means is a third running in which the lock-up clutch is in an engaged state, and the primary rotational frequency of the tire matches the torsional natural frequency between the continuously variable transmission and the tire. In the state, when the line pressure is equal to or lower than the predetermined pressure, the line pressure is increased so as to be higher than the predetermined pressure. The control device for a continuously variable transmission according to any one of claims 1 to 3,
The control means is configured to increase the line pressure higher than the predetermined pressure when the accelerator pedal opening is within a predetermined opening range including the first traveling state and the line pressure is equal to or lower than the predetermined pressure. A control device for a continuously variable transmission, wherein the continuously variable transmission is raised. The control device for a continuously variable transmission according to any one of claims 1 to 4,
The control means increases the line pressure to be higher than the predetermined pressure when the vehicle pressure is within a predetermined vehicle speed range including the first traveling state and the line pressure is equal to or lower than the predetermined pressure. A control device for a continuously variable transmission.

Images