JP2022036327A - Controller and control method for continuously variable transmission - Google Patents

Abstract

To perform abnormality removal operation quickly in a case where abnormality resulting from foreign matter occurs in a valve.SOLUTION: A controller for a continuously variable transmission 1 comprises a primary pulley 4, a secondary pulley 5, and a belt 6 wound around both pulleys, and comprises a solenoid valve 63 for hydraulic control that is connected to a vehicle drive source 10 and controls a gear ratio. The controller comprises determination means 71 that determines that a delay has occurred in the change in actual pressure with respect to the change in indicated pressure to the solenoid valve 63 for hydraulic control, and valve control means 72 that when the determination means determines that a delay has occurred, performs foreign matter removal operation that temporarily reciprocates a spool of the solenoid valve 63 for hydraulic control.SELECTED DRAWING: Figure 1

Description

The present invention relates to a continuously variable transmission control device and a control method for controlling a continuously variable transmission in consideration of a case where a malfunction occurs due to a foreign substance being caught in a valve.

A linear solenoid valve (hereinafter, also simply referred to as a valve) that generates a control pressure based on an input signal is used in a control device of an automatic transmission for a vehicle. In this valve, the hydraulic pressure is adjusted and control pressure is generated by the spool moving in the axial direction by a solenoid in a sleeve provided with an input port, an output port, a drain port and the like. When the output hydraulic pressure is regulated, the clearance between the input port and drain port is extremely small, so foreign matter such as iron powder mixed in the oil gets caught in the clearance of this port and interferes with proper hydraulic control. There is a risk of causing it.

Therefore, for example, as disclosed in Patent Document 1, a technique has been developed for performing a foreign matter removing operation in which a solenoid is operated to temporarily reciprocate the spool.
In the technique of Patent Document 1, before the start of N control (control to reduce the torque transmitted by the input clutch while the vehicle is stopped in the traveling range) or when the vehicle is stopped and N control is performed. The foreign matter removal operation is performed immediately after the end. At these timings, the engagement pressure of the input clutch hardly fluctuates even when the foreign matter removal operation is performed, so that a shock is not generated due to the fluctuation of the engagement pressure of the input clutch.

Japanese Unexamined Patent Publication No. 2008-101632

By the way, as described in Patent Document 1, in a configuration in which the vehicle is stopped and the foreign matter removal operation is performed at the timing before the start or the end of the N control, the foreign matter removal operation is performed after the abnormality that the foreign matter is caught in the valve occurs. There may be a time lag before performing. That is, even if an abnormality caused by a foreign matter occurs in the valve, the foreign matter removal operation is not performed until the timing when the above condition is satisfied. Therefore, during this period, the abnormal state of the valve is continued and the automatic transmission is operated. In the case of a belt-type continuously variable transmission, the belt slip may cause damage to the continuously variable transmission.

The present invention was devised focusing on such a problem, and is a control device for a continuously variable transmission capable of promptly performing a foreign matter removing operation when an abnormality caused by a foreign matter occurs in the valve. And to provide a control method.

(1) In order to achieve the above object, the control device for the stepless transmission of the present invention includes a primary pulley, a secondary pulley, and a belt wound around both pulleys, and is hydraulically controlled to control the gear ratio. A determination device for a stepless transmission that controls a stepless transmission equipped with a solenoid valve for hydraulic pressure, and determines that a delay has occurred in the change in actual pressure with respect to the change in the instruction pressure to the solenoid valve for hydraulic pressure control. It is characterized by comprising means and valve control means for performing a foreign matter removing operation of temporarily reciprocating the spool of the hydraulic control solenoid valve when the determination means determines the occurrence of the delay.

(2) It is preferable that the determination means determines that the delay has occurred when the amount of change in the difference between the indicated pressure and the actual pressure becomes a predetermined amount or more.
(3) The determination means has a first offset, which is the difference between the indicated pressure and the actual pressure when at least one of the input to the continuously variable transmission and the gear ratio is a steady state, and the above. The second offset, which is the difference between the indicated pressure and the actual pressure when one of the states is a transient state, is compared, and when the difference between the second offset and the first offset is larger than a predetermined value, the said It is preferable to determine that a delay has occurred.
(4) The secondary pressure applied to the secondary pulley is controlled by the secondary instruction pressure according to the magnitude of the input torque to the stepless transmission, and the primary pressure applied to the primary pulley is the gear ratio and the above. The hydraulic pressure control solenoid valve is controlled by a primary instruction pressure corresponding to the secondary pressure, and is preferably a primary valve that controls the primary pressure, and the instruction pressure is preferably the primary instruction pressure.

(5) The control method of the stepless transmission of the present invention is a control method of a solenoid valve for hydraulic pressure control for controlling the gear ratio of the stepless transmission, and is actually a change in the instruction pressure to the solenoid valve for hydraulic pressure control. A valve that performs a foreign matter removal operation that temporarily reciprocates the spool of the hydraulic control solenoid valve after determining the occurrence of the delay in the determination step for determining whether or not a delay has occurred in the pressure change. It is characterized by having a control step.

According to the present invention, when a delay occurs in the change in the actual pressure with respect to the change in the indicated pressure to the solenoid valve for hydraulic pressure, a foreign matter removing operation for temporarily reciprocating the spool of the solenoid valve for hydraulic pressure is performed, so that hydraulic control is performed. It is possible to quickly eliminate the abnormality of the solenoid valve.

In other words, if the hydraulic control solenoid valve is normal, there will be no delay (delay above a certain level) in the change in actual pressure when the indicated pressure of the hydraulic control solenoid valve changes, but the hydraulic control solenoid valve is abnormal. In this case, there may be a delay in the change in the actual pressure when the indicated pressure changes, and in this case, it is extremely likely that the belt slips at the same time. Therefore, if the cause of the abnormality of the hydraulic control solenoid valve is the biting of foreign matter by performing the foreign matter removal operation when a delay occurs, if the foreign matter can be removed by the foreign matter removal operation, the hydraulic control solenoid valve is in the normal state. It is possible to prevent the recurrence of the slip of the belt.

It is a block diagram of the drive system of a vehicle which concerns on one Embodiment of this invention, a continuously variable transmission, and the control device thereof. It is a time chart explaining the control principle by the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a flowchart explaining an example of the determination (abnormality determination) of the valve malfunction by the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a flowchart explaining an example of the foreign matter removal and protection control by the control device of the continuously variable transmission which concerns on one Embodiment of this invention. It is a time chart explaining an example of control by the control device of the continuously variable transmission which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiments shown below are merely examples, and there is no intention of excluding the application of various modifications and techniques not specified in the following embodiments. Each configuration of the following embodiments can be variously modified and implemented without departing from the purpose thereof, and can be selected as necessary or combined as appropriate.

[Overall system configuration]
FIG. 1 is a configuration diagram showing a vehicle according to the present embodiment, a continuously variable transmission mounted on the vehicle, and a main part of the control device thereof.
As shown in FIG. 1, the stepless transmission (CVT) 1 includes an input shaft 2 driven and connected to an output shaft 10a of an engine (internal engine) 10 as a drive source via a torque converter 11, and an input shaft 2. The output shaft 3 which is arranged in parallel with the drive wheel 12 and is driven and connected via the speed reducer 13 and the differential mechanism 14, the primary pulley 4 connected to the input shaft 2, and the secondary connected to the output shaft 3. It includes a pulley 5 and an endless belt 6 wound around the primary pulley 4 and the secondary pulley 5.

The primary pulley 4 has a fixed sheave 41, a movable sheave 42, and a primary oil chamber 43 for moving the movable sheave 42 in the axial direction.
The secondary pulley 5 has a fixed sheave 51, a movable sheave 52, and a secondary oil chamber 53 that moves the movable sheave 52 in the axial direction.

The stepless transmission 1 has a predetermined line pressure of the oil pump 61 driven by the engine 10 and the hydraulic oil discharged from the oil pump 61 in order to supply the hydraulic oil to the primary oil chamber 43 and the secondary oil chamber 53. A line pressure control valve (pressure regulator valve) 62 that regulates the pressure to PL, a primary pressure control valve 63 that regulates the primary pressure _Ppri using the line pressure _PL as the main pressure, and a secondary pressure _Psec using the line pressure PL as the main pressure. It is equipped with a secondary pressure control valve 64 for adjusting the pressure.

Each of the control valves 62, 63, 64 is provided in the hydraulic control circuit 60, and although details are not shown, a solenoid valve for driving a spool built in a sleeve equipped with an input port, an output port, a drain port, etc. by a solenoid. The CVT ECU (CVT electronic control unit) 7 controls the currents to the solenoids 62a, 63a, 64a, thereby driving the spool and adjusting the output hydraulic pressure. Therefore, the control valves 62, 63, 64 are also referred to as "hydraulic control solenoid valves".

The CVTEC 7 detects the rotation speed of the primary pulley 4 (unit time rotation speed, primary pulley rotation speed) Npri, the primary rotation sensor 81, and the rotation speed of the secondary pulley 5 (unit time rotation speed, secondary pulley rotation speed) Nsec. Various sensors such as a secondary rotation sensor 82, a primary pressure sensor 83 for detecting the pressure (primary pressure) Ppri of the primary oil chamber 43, and a secondary pressure sensor 84 for detecting the pressure (secondary pressure) Psec of the secondary oil chamber 53 are connected. , These sensor information and switch information are input. Further, the CVT ECU 7 is connected to the engine ECU (engine electronic control unit) 8 so as to be able to transmit information.

The continuously variable transmission 1 applies the lowest possible thrust to each of the pulleys 4 and 5 as long as slip does not occur between the belt 6 and the pulleys 4 and 5, and when the gear ratio R is changed, the primary pulley 4 A differential thrust is applied between the and the secondary pulley 5 to drive the movable sheaves 42 and 52 in the axial direction so that the target gear ratio Ratio 0 is achieved. These thrusts and differential thrusts are performed by controlling the primary pressure Ppri and the secondary pressure Psec by the CVTEC7.

[Hydraulic control system configuration]
Therefore, although the details are not shown, the CVT ECU 7 has a line pressure control unit that controls the line pressure PL, a primary pressure control unit that controls the primary pressure _Ppri , and a secondary pressure control unit that controls the secondary pressure Psec. A shift control unit (shift control means) 70 is provided.
Further, the CVT ECU 7 includes a gear ratio calculation unit (not shown) that calculates the actual gear ratio Ratio from the primary pulley rotation speed Npri and the secondary pulley rotation speed Nsec.

The line pressure control unit outputs a predetermined control command (line pressure instruction value) to the line pressure solenoid 62a.
The primary pressure control unit outputs a control command (primary pressure instruction value Ppri_d) for obtaining a predetermined primary pressure target value Ppri_t to the primary hydraulic solenoid 63a.
The secondary pressure control unit outputs a control command (secondary pressure instruction value Psec_d) for obtaining a predetermined secondary pressure target value Psec_t to the secondary hydraulic solenoid 64a.

More specifically, the secondary pressure control unit calculates the torque capacity (required torque transmission capacity) transmitted by the continuously variable transmission 1 based on the output information from the engine ECU 8 and the vehicle speed information from the secondary rotation sensor 82. The secondary pressure target value Psec_t corresponding to the required thrust is derived from this transmission torque capacity, and the secondary pressure instruction value Psec_d is set. The secondary pressure instruction value Psec_d is set by adding the feedback correction amount based on the secondary actual pressure Psec to this secondary pressure target value Psec_t. Therefore, the secondary pressure Psec is controlled by the feedback control (PID control) based on the secondary actual pressure Psec.

The primary pressure control unit has a target gear ratio Ratio 0 calculated based on output information from the engine ECU 8 and vehicle speed information from the secondary rotation sensor 82, an actual gear ratio Ratio calculated by the gear ratio calculation unit (not shown), and a secondary pressure. The primary pressure target value Ppri_t is set from the indicated value (secondary indicated pressure) Psec_d, and the primary pressure indicated value (primary indicated pressure) Ppri_d is set from the primary pressure target value Ppri_t and the primary actual pressure Ppri. That is, in the primary pressure control unit, the relationship with the secondary pressure indicated value Psec_d corresponds to the target difference thrust by the feedback control (PID control) based on the deviation (Ratio0-Ratio) between the target gear ratio Ratio 0 and the actual gear ratio Ratio. The primary pressure indicated value Ppri_d is set while considering the actual pressure Ppri by giving the primary pressure target value Ppri_t.

The line pressure control unit can achieve the secondary pressure indicated value Psec_d and the primary pressure indicated value Ppri_d based on the secondary pressure indicated value Psec_d and the primary pressure indicated value Ppri_d, so that the secondary pressure indicated value Psec_d and the primary pressure indicated value Ppri_d can be achieved. The line pressure indicated value PL _{_d} , which is higher by the margin (differential pressure ΔP0) than the larger one, is set.

By the way, the control valves 62, 63, 64 provided in such a continuously variable transmission 1 are hydraulic control solenoid valves that adjust the output hydraulic pressure by controlling the current to the solenoids 62a, 63a, 64a. However, foreign matter (also called contaminants or contamination) such as iron powder mixed in the oil gets caught in the extremely small clearance between the input port or drain port and the spool, so-called valve stick. May interfere with proper hydraulic control. In this case, it is highly possible that belt slippage occurs at the same time.

This device determines whether or not the valve is malfunctioning, and if it is determined that the valve is malfunctioning, it first performs a foreign matter removal operation that attempts to eliminate the malfunction due to the biting of foreign matter. do. If the malfunction is still not resolved, the thrust of the pulley may decrease due to insufficient hydraulic pressure due to the malfunction of the valve, causing malfunction of the continuously variable transmission 1 such as belt slippage, which may lead to damage to the continuously variable transmission 1. Therefore, the protection control of the continuously variable transmission 1 is carried out.
Hereinafter, the foreign matter removing operation and the protection control will be described with a focus on the primary pressure control valve 63.

As shown in FIG. 1, the CVTEC 7 has a determination unit (determination means) 71 for determining whether or not the valve is malfunctioning, and when the determination unit 71 determines that the valve is malfunctioning, foreign matter is removed. If the valve control unit (valve control means) 72 that operates and the protection control unit that performs protection control of the continuously variable transmission 1 continue to be determined that the valve is malfunctioning even after the foreign matter removal operation is performed (valve control unit) ( (Protection control means) 73 and.

In the determination by the determination unit 71 whether or not the valve is malfunctioning, whether or not there is a delay in the change (here, increase) in the primary actual pressure Ppri with respect to the change (here, increase) in the primary instruction pressure Ppri_d. It is judged by whether. That is, if the change in the primary actual pressure Ppri is delayed by a certain amount or more with respect to the change in the primary indicated pressure Ppri_d, it is determined that the valve is malfunctioning (that is, belt slippage has occurred).

By the way, as described above, since the secondary indicated pressure Ppri_d is set from the secondary pressure target value Psec_t according to the required thrust, it is necessary to appropriately grasp the value of the secondary actual pressure Psec used for the feedback control. Therefore, the secondary pressure sensor 84 that detects the secondary actual pressure Psec is calibrated in advance.
Therefore, in the case of the secondary pressure control valve 64, if there is no delay in the change in the secondary actual pressure Psec with respect to the change in the secondary indicated pressure Psec_d, the secondary actual pressure Psec is almost the same as the secondary indicated pressure Psec_d (both). If the difference is small) and the delay occurs, the difference between the secondary actual pressure Psec and the secondary instruction pressure Psec_d becomes a certain value or more. From this, it is possible to determine the occurrence of the delay.

On the other hand, the primary indicated pressure Ppri_d is set from the primary pressure target value Ppri_t corresponding to the target gear ratio Ratio 0, the actual gear ratio Ratio, and the secondary indicated pressure Psec_d, so that the primary actual pressure Ppri used for feedback control is detected. Even if the value deviates from the actual value, feedback control can be performed without any problem. Therefore, the primary pressure sensor 83 that detects the primary actual pressure Ppri is used without performing calibration for correcting the deviation from the actual value in such a detected value.

Under such circumstances, it is assumed that the detected value of the primary pressure sensor 83 has a certain deviation in the positive direction or the negative direction with respect to the actual value. Therefore, even if attention is paid to the difference between the primary indicated pressure Ppri_d and the primary actual pressure Ppri, the delay in the change in the primary actual pressure Ppri with respect to the change in the primary indicated pressure Ppri_d cannot be properly determined.
Therefore, the determination unit 71 determines the amount of change in the difference between the indicated pressure Ppri_d and the actual pressure Ppri on the precondition that the gear ratio R is in a steady state (in other words, the continuously variable transmission 1 is in a steady state). When the amount exceeds the fixed amount, it is determined that a delay has occurred in the change in the actual pressure Ppri.

Regarding the above-mentioned determination condition that the gear ratio R is in the steady state, here, the Ratio difference (= | DRatio-Ratio0 |), which is the difference between the reached gear ratio DRatio and the target gear ratio Ratio0, is the determination reference value (small value). ) It is assumed that the state in which the Ratio difference is equal to or less than the judgment reference value α as compared with α has continued for a predetermined time of P1 or more.

The reached gear ratio DRatio is set based on the running condition of the vehicle, and the target gear ratio Ratio 0 is set to reach (converge) the actual gear ratio Ratio to this reached gear ratio DRatio at a predetermined change speed. In the transient state, the reached gear ratio DRatio is changed, and the target gear ratio Ratio0 is changed accordingly. However, since the change in the target gear ratio Ratio0 is suppressed to a small extent, the Ratio difference becomes the determination reference value α or more. Therefore, such a determination method is used to determine the steady state.

In order to determine the steady state, it is a prerequisite that the input torque from the engine 10 of the drive source to the continuously variable transmission 1 is in the steady state, in addition to or in place of the gear ratio R being in the steady state. May be.

Regarding the determination of the delay in the change in the primary actual pressure Ppri with respect to the change in the primary indicated pressure Ppri_d, specifically, the determination unit 71 determines the indicated pressure Pd (here, the primary) when the stepless transmission 1 is in the steady state. The first offset Offf1 (= Pd-Pr), which is the difference between the indicated pressure Ppri_d) and the actual pressure Pr (here, the primary actual pressure Ppri), and the transient state (in other words, the gear ratio R fluctuates from this steady state). The second offset Off2 (= Pd-Pr), which is the difference between the indicated pressure Pd (primary indicated pressure Ppri_d) and the actual pressure Pr (primary actual pressure Ppri) when the stepless transmission 1 is in the transient state). When the difference Dif (= Offf2-Offf1) between the second offset Off2 and the first offset Offf1 is larger than the predetermined difference Dif0, it is determined that a delay has occurred in the change in the actual pressure Pr.

Regarding the determination that the gear ratio R has become a transient state, the deviation between the target gear ratio Ratio 0 and the actual gear ratio Ratio (= | Ratio0-Ratio |) is determined when the Ratio difference is equal to or less than the determination reference value α. When this deviation becomes equal to or greater than the determination reference value β in comparison with the determination reference value (small value) β, it is determined that the gear ratio R is in a transient state. The judgment reference value β is a value at substantially the same level as the judgment reference value α (a value equal to or slightly smaller than the judgment reference value α). On the contrary, in order to judge the steady state, it is included in the condition that this deviation is less than the judgment reference value β.

Specifically, the foreign matter removing operation by the valve control unit 72 temporarily (constant time) a dither control current in which the current changes in a predetermined cycle to the solenoid (primary solenoid 63a) of the valve (primary valve 63). ), The spool of the valve 63 is temporarily reciprocated (“dither control”). The length of time for performing this foreign matter removing operation (the period during which the current for dither control is passed) may be appropriately set. If the detected pressure regulation defect is temporarily generated due to contamination or the like, it can be expected that the pressure regulation defect will be resolved by performing a foreign matter removing operation.

Specifically, the protection control by the protection control unit 73 applies the input torque limit control that limits the input torque from the engine 10 to the continuously variable transmission 1. When the actual pressure Pr of the hydraulic oil to the pulley 4 is lower than the indicated pressure Pd by a certain amount (margin) or more, the slip of the belt 6 of the continuously variable transmission 1 is a pulley with respect to the input torque to the continuously variable transmission 1. It occurs due to insufficient thrust of 4. Therefore, in order to suppress the occurrence of slippage of the belt 6 and protect the continuously variable transmission 1, it is effective to limit the input torque (torque generated by the drive source 10) to the continuously variable transmission 1.

Here, with reference to the time chart of FIG. 2, an example of determination by the determination unit 71 and control according to the determination result will be described.

The time chart of FIG. 2 shows a plurality of flags.
Of these, the flag F1 is a steady-state determination flag that is set to 1 when the gear ratio R is in a steady state for a predetermined period (or a predetermined time) or longer, and is set to 0 until a steady-state determination is made.
The flag F2 is a steady-state determination clear flag (transient determination flag) in which the gear ratio R is 1 (clear) in the steady state and 0 (set) in the transient state.
The flag F3 is a slip region determination flag which is set to 1 in an operating region where there is a possibility of belt slip due to a delay in the change of the actual pressure Pr with respect to the change of the indicated pressure Pd, and is set to 0 in the other operating regions.
Flag F4 is an emergency dither operation request flag that is set to 1 when requesting operation of dither processing (emergency dither) as a foreign matter removal operation in an operating area where belt slippage is possible, and is set to 0 in other cases. be.
Flag F5 is a slip determination flag that is set to 1 when the operating area has a possibility of belt slip (flag F3 = 1) and emergency dither is performed (flag F4 = 1), and is set to 0 in other cases. ..

First, at the time point t1 shown in FIG. 2, the difference (= DRatio-Ratio0) between the reached gear ratio DRatio and the target gear ratio Ratio0 becomes the determination reference value α or less, and this state continues until the time point t2 after the predetermined time P1. It is determined that the state is steady, and the steady state determination flag F1 is turned on (F1 = 1).

If the steady state determination flag F1 is on and the steady state determination clear flag F2 is in the clear state (steady state determination allowable state, F2 = 1), the gear ratio R is in the steady state, and the instruction pressure Pd (primary instruction pressure Ppri_d). The first offset Off1 (= Pd-Pr), which is the difference between the actual pressure Pr and the actual pressure Pr (primary actual pressure Ppri), is calculated.

At the subsequent time point t3, the reached gear ratio DRatio and the target gear ratio Ratio0 do not fluctuate, but only the actual gear ratio Ratio fluctuates (here, increases) and the deviation between the target gear ratio Ratio0 and the actual gear ratio Ratio (= | When Ratio0-Ratio |) becomes the determination reference value β or more, the steady determination clear flag F2 is in the set state (F2 = 0), and the gear ratio R is determined to be in the transient state. At this time, the offset Offf also increases to a value Offfs larger than that of the first offset Offf1.
In this state, the second offset Off2 (= Pd-Pr), which is the difference between the indicated pressure Pd (primary indicated pressure Ppri_d) and the actual pressure Pr (primary actual pressure Ppri), is calculated.

When the second offset Off2 increases and the difference Dif (= Off2-Offf1) between the second offset Off2 and the first offset Off1 reaches the predetermined difference Dif0 at the time point t4, the change of the actual pressure Pr is delayed. The slip area determination flag F3, which indicates that the belt is in a region where slippage is a concern, is turned on (F3 = 1), and at the same time, the emergency dither operation request flag F4 is turned on (F4 = 1). Dither (foreign matter removal operation) is performed by dither control. The slip area determination flag F3 and the emergency dither operation request flag F4 continue to be on for a certain period of time and return to off at a time point t7 after a certain period of time.

Further, the slip determination flag F5 is turned on (F5) at an appropriate timing (here, the timing at which the gear ratio R is constantly restored) t6 while the slip area determination flag F3 and the emergency dither operation request flag R4 are in the ON state. = 1) is set.
The steady determination flag F1, the steady determination clear flag F2, and the slip determination flag F5 are reset (F1 = 0, F2 =) at the timing (time point t7) when the slip area determination flag F3 and the emergency dither operation request flag F4 return to off. 1, F5 = 0). However, the steady-state determination clear flag F2 may be reset after a predetermined time P2 from the timing T6 at which the gear ratio R has returned to steady state, as shown by the alternate long and short dash line.
Then, the slip counter is counted according to the number of times the slip determination flag is set to ON within a predetermined period, and when the count value C of the slip counter reaches a predetermined number, the above protection control is executed.

[Action and effect]
Since the continuously variable transmission control device according to the present embodiment is configured as described above, the continuously variable transmission can be controlled as shown in FIGS. 3, 4 and 5.
In the control example shown here, if the slip determination flag is turned on again within the predetermined distance Ms after the slip determination flag is turned on once, the protection control is performed. It is set.

First, it is determined whether or not there is a delay in the change in the actual pressure Pr with respect to the change in the indicated pressure Pd (that is, whether or not the belt slips).
That is, as shown in FIG. 3, it is determined whether or not the gear ratio R has been in a steady state for a predetermined period (or a predetermined time) or more (step S11). If it is not in a steady state for a predetermined period or more, it returns. If it is in a steady state for a predetermined period or longer, the steady state determination flag F1 is set to on (F1 = 1) (step S12), and then it is determined whether or not it is currently in a steady state (step S13). If it is in the steady state, the first offset Off1 (= Pd-Pr), which is the difference between the indicated pressure Pd and the actual pressure Pr, is calculated (step S14).

On the other hand, if it is not in the steady state at present, the steady state determination clear flag F2 is set (F2 = 0) (step S15), and the second offset Off2 (= Pd-Pr) which is the difference between the indicated pressure Pd and the actual pressure Pr. Is calculated (step S16). Then, the difference Dif (= Offf2-Offf1) between the second offset Off2 and the first offset Offf1 is calculated (step S17), and it is determined whether or not the difference Dif is equal to or greater than the predetermined difference Dif0 (step S18). When the mileage M becomes a predetermined distance Ms or more, it is determined that the change in the actual pressure Pr with respect to the change in the indicated pressure Pd has occurred, and the slip area determination flag F3 is set to ON (F3 = 1) (step S19). ..

As shown in FIG. 4, each process of dither processing and protection control is performed based on the determination of whether or not the change of the actual pressure Pr with respect to the change of the indicated pressure Pd has occurred. If there is no delay in the change of the actual pressure Pr (if the slip region determination flag F3 is 0), these processes are not performed.

First, it is determined whether or not the mileage (mileage count value) M is equal to or greater than the predetermined distance Ms (step S2). The mileage M is a distance count value that starts counting when the slip determination flag is turned on.
If the mileage M is a predetermined distance Ms or more, the mileage M is reset to 0 (step S4), the flag F6 described later is reset to 0 (step S6), and the count value C of the slip counter is reset to 0. (Step S8).

Next, it is determined whether or not there is a delay in the change in the actual pressure Pr with respect to the change in the indicated pressure Pd (whether or not the slip region determination flag F3 is 1) (step S10).
When it is determined that the change in the actual pressure Pr with respect to the change in the indicated pressure Pd has occurred (F3 = 1), it is first determined whether or not the flag F6 is 0 (step S20). This flag F6 is set to 1 when the slip determination is made and the dither processing is performed once, and then set to 0 if the slip determination is not made until the mileage M of the vehicle becomes a predetermined distance Ms or more. It is reset (step S6).

If the flag F6 is 0, the flag F6 is set to 1 (step S30), the counting of the mileage M of the vehicle is started (step S40), the emergency dither operation request flag F4 is set to 1, and the dither processing (foreign matter) is performed. The removal operation) is carried out for a predetermined time (step S50). Then, the slip determination flag F5 is set to 1 (step S52), it is determined whether or not the dither processing (foreign matter removing operation) is continued for a predetermined time (step S54), and if the dither processing is continued for a predetermined time, each flag is set. Reset F1 to F6 (step S56)

On the other hand, if the flag F6 is not 0, the flag F6 is 1, the counting of the mileage M of the vehicle is continued (step S58), and the dither processing (foreign matter removing operation) is performed for a predetermined time (step S60). Then, the slip determination flag F5 is set to 1 (step S62), the count value C of the slip counter is incremented (step S64), and whether or not the count value C is equal to or greater than the threshold Cs (here, Cs = 2). (Step S66).

If the count value C is not equal to or greater than the threshold value Cs, it is determined whether or not the dither processing (foreign matter removing operation) is continued for a predetermined time (step S54), and if the dither processing is continued for a predetermined time, the flags F1 to F6 are reset. (Step S56)
On the other hand, if the count value C is equal to or higher than the threshold value Cs, the protection control of the continuously variable transmission 1 is performed (step S70).
In this case, a warning is displayed on the vehicle and the driver is informed of the repair.

5A and 5B are time charts corresponding to the flowcharts of FIGS. 3 and 4. In FIG. 5, VSS indicates a vehicle speed and TVO indicates a throttle opening degree.
As shown in FIG. 5, belt slip is detected due to a delay in the change in the actual pressure Pr with respect to the change in the indicated pressure Pd at the time point t11, and dither processing is performed (dither operation) at the time points t11 to t12. The slip flag is set. Further, the slip counter is switched from 0 (normal) to 1 (temporary failure).
After that, since the belt slip is not detected until the time point t13 when the mileage M of the vehicle becomes the predetermined distance Ms or more, the slip counter is reset to 0 (normal).

After that, the belt slip was detected because the change of the actual pressure Pr with respect to the change of the indicated pressure Pd occurred at the time point t14, and the dither treatment was performed (dither operation) at the time points t14 to t15, and the slip flag was set. To. Further, the slip counter is switched from 0 (normal) to 1 (temporary failure). When belt slip is detected at a time point t16 before the vehicle's mileage M becomes a predetermined distance Ms or more, dither processing is performed (dither operation) at time points t16 to t17, a slip flag is set, and a slip counter is set. The protection control of the continuously variable transmission 1 is carried out by switching from 1 (temporary failure) to 2 (fixed failure).

In this way, according to the present device, if there is a delay in the change in the actual pressure Pr with respect to the change in the indicated pressure Pd to the primary control valve 63, which is the solenoid valve for hydraulic control, the belt slip due to the malfunction of the valve 63. Although the possibility of occurrence is high, since the foreign matter removing operation of temporarily reciprocating the spool of the valve 63 is performed, it is possible to quickly eliminate the malfunction of the valve 63.

Further, if the malfunction of the valve 63 is not resolved, or if the malfunction of the valve 63 is resolved but the malfunction of the valve 63 occurs again within a long period of time, the continuously variable transmission 1 is protected. Since the control is performed, for example, the occurrence of belt slippage can be quickly suppressed, and damage to the continuously variable transmission 1 can be avoided.

It is possible to perform the protection control immediately when the delay occurs, but if the foreign matter removal operation is performed before the protection control is performed, the malfunction of the valve 63 can be quickly resolved. Thus, if the malfunction of the valve 63 is eliminated, the protection control becomes unnecessary, and it is possible to avoid the deterioration of the driving performance of the vehicle due to the protection control.

Further, since the primary control valve 63 is used without being calibrated to correct the deviation from the actual value in the detected value, a simple comparison between the indicated pressure Pd to the valve 63 and the actual pressure Pr is used. Although it is not possible to determine the malfunction of the valve 63, the malfunction of the valve 63 is determined because the change in the actual pressure Pr with respect to the change in the indicated pressure Pd to the valve 63 is delayed. Can be done.

Although the embodiment of the present invention has been described above, the present invention may be carried out by appropriately modifying such an embodiment.
For example, in the above embodiment, the foreign matter removing operation and protection control related to the primary control valve 63 have been described, but the present invention can also be applied to the management of other hydraulic control solenoid valves such as the secondary control valve 64.

Further, in the above embodiment, if there is a delay in the change in the actual pressure Pr with respect to the change in the indicated pressure Pd, dither (foreign matter removing operation) is performed, and if there is still a delay in the change in the actual pressure Pr, protection control is performed. However, protection control may be omitted.

1 Continuously variable transmission for vehicles (CVT)
4 Primary pulley 5 Secondary pulley 6 Endless belt 63 Primary pressure control valve (solenoid valve for hydraulic control)
63 Secondary pressure control valve (solenoid valve for hydraulic control)
70 Shift control unit (shift control means)
71 Judgment unit (judgment means)
72 Valve control unit (valve control means)
73 Protection control unit (protection control means)

Claims (5)

A continuously variable transmission control device that controls a continuously variable transmission equipped with a primary pulley, a secondary pulley, a belt wound around both pulleys, and a solenoid valve for hydraulic control that controls a gear ratio.
A determination means for determining that a delay has occurred in the change in the actual pressure with respect to the change in the indicated pressure to the solenoid valve for hydraulic pressure control, and
A continuously variable transmission comprising: a valve control means for performing a foreign matter removing operation of temporarily reciprocating the spool of the hydraulic control solenoid valve when the determination means determines the occurrence of the delay. Control device. The stepless speed change according to claim 1, wherein the determination means determines that the delay has occurred when the amount of change in the difference between the indicated pressure and the actual pressure becomes a predetermined amount or more. Machine control device. The determination means has a first offset, which is the difference between the indicated pressure and the actual pressure when at least one of the input to the continuously variable transmission and the gear ratio is a steady state, and one of the states. Compares the second offset, which is the difference between the indicated pressure and the actual pressure when is in a transient state, and when the difference between the second offset and the first offset is larger than a predetermined value, the delay occurs. The control device for a continuously variable transmission according to claim 1, wherein it is determined that the operation has been performed. The secondary pressure applied to the secondary pulley is controlled by the secondary indicated pressure according to the magnitude of the input torque to the continuously variable transmission.
The primary pressure applied to the primary pulley is controlled by the primary indicated pressure according to the gear ratio and the secondary pressure.
The stepless step according to any one of claims 1 to 3, wherein the hydraulic control solenoid valve is a primary valve that controls the primary pressure, and the indicated pressure is the primary indicated pressure. Transmission control device. It is a control method of a solenoid valve for hydraulic control that controls the gear ratio of a continuously variable transmission.
A determination step for determining whether or not there is a delay in the change in the actual pressure with respect to the change in the indicated pressure to the solenoid valve for hydraulic pressure control, and
The continuously variable transmission is provided with a valve control step for performing a foreign matter removing operation of temporarily reciprocating the spool of the hydraulic control solenoid valve when the occurrence of the delay is determined in the determination step. Control method.

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