JP3399313B2 - Hydraulic control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for an automatic transmission mounted on an automobile, and more particularly to a hydraulic control system for an automatic transmission that corrects shift control by learning.

[0002]

2. Description of the Related Art Conventionally, a turbine (input) during shifting
A hydraulic control device for an automatic transmission, which controls the above-mentioned rotation change rate to a target rotation change rate by learning-controlling an initial engagement pressure based on the detection of the rotation change rate of the number of rotations, is disclosed in Japanese Patent Application Laid-Open No. HEI-1.
It is disclosed in Japanese Patent Publication No. 98745. This one detects the rotation change rate of the input rotation speed at the time of gear shift by engaging a predetermined friction engagement element, and at the time of the next gear shift, the difference between the detected rotation change rate and the target rotation change rate causes This is to correct the operating oil pressure of the predetermined friction engagement element. Specifically, when the rotation change rate is larger than the target change rate, it is determined that the engagement operation speed of the predetermined friction engagement element is too fast, and the operation is performed. If the rotation change rate is smaller than the target change rate, it is judged that the engagement actuation speed is too slow, and the working oil pressure is corrected to become larger. It is intended to eliminate the decrease in control accuracy due to the operation delay of the hydraulic pressure control by effectively reflecting the shift shock and to effectively suppress the shift shock and excessive slippage.

[0003]

However, in general, the engagement operation of the friction engagement element, that is, the initial engagement pressure is set by the input torque. When the input torque is extremely small (for example, in the power off state), the servo start control is terminated when the initial engagement pressure is learned and corrected to achieve the target rotation change rate. If the oil pressure is increased from the predetermined low pressure to the engagement initial pressure set by the input torque, the gear shift is started in the low pressure state because the engagement initial pressure is lower than the predetermined low pressure. Therefore, even if the initial engagement pressure set by the input torque at that time is corrected, the rotation change rate at the start of the shift does not converge toward the target rotation change rate at the next shift, and appropriate learning control is performed. I can't.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hydraulic control system for an automatic transmission that always performs appropriate learning control irrespective of the magnitude of input torque to reduce the occurrence of malfunctions such as gear shift shocks. And

[0005]

According to a first aspect of the present invention, there is provided an input shaft to which power is input from an engine output shaft, an output shaft connected to a wheel, and the input shaft and the output shaft. A plurality of friction engagement elements that change the power transmission path, and a hydraulic servo (9, 1) that disconnects / engages these friction engagement elements.
0) and a hydraulic control device for an automatic transmission including: pressure adjusting means (SLS, SLU) for adjusting the engagement pressure supplied to at least the hydraulic servo of the friction engagement element on the engagement side.
And a traveling condition detecting means (2 to 3) for detecting the traveling condition of the vehicle.
7) and the piston (1) of the hydraulic servo (10) in a state immediately before the engagement side frictional engagement element produces torque capacity.
9) Servo start control for performing servo start control having fast fill that outputs a predetermined high pressure (P _S1 ) that strokes and low pressure standby that outputs a predetermined low pressure (P _S2 ) that holds the piston in a stroked state Means (1a),
After the completion of the servo start control, an engagement control means (1b) for increasing the hydraulic pressure toward a target engagement pressure (P _TA ) set based on the input torque, and a predetermined value calculated based on the traveling state detection means. When the input torque (T _T ) is equal to or more than a predetermined value so that (ωs ′) becomes a preset target value,
Learning control means (1c) for correcting the target engagement pressure (P _TA ) and correcting the predetermined low pressure (P _S2 ) when the input torque is equal to or less than a predetermined value. It is in the hydraulic control of the transmission.

According to the second aspect of the present invention, the input shaft to which power is input from the engine output shaft, the output shaft connected to the wheels, and the power transmission path between the input shaft and the output shaft are changed. In a hydraulic control device for an automatic transmission, which comprises a plurality of friction engagement elements and hydraulic servos (9, 10) for connecting / disconnecting the friction engagement elements, at least engagement side friction engagement elements The pressure adjusting means (SLS, SLU) for adjusting the engagement pressure supplied to the hydraulic servo, the traveling situation detecting means (2-7) for detecting the traveling situation of the vehicle, and the engagement side friction engagement element A fast fill that outputs a predetermined high pressure (P _S1 ) that strokes the piston (19) of the hydraulic servo (10) immediately before the torque capacity is generated, and a predetermined low pressure (P _S2 ) that holds the piston in a stroked state. Output low pressure wait When, a servo activation control means for performing servo activation control having a (1a), after the servo activation control end, the target engagement pressure is set based on the input torque (P _TA)
Engagement control means (1b) for increasing the hydraulic pressure toward a predetermined value, and a predetermined value (ωs') calculated based on the running condition detection means.
If the target engagement pressure (P _TA ) is higher than a predetermined reference pressure (P _S2 + P _OFFSET ), the target engagement pressure (P _TA ) is corrected so that When the engagement pressure is lower than the predetermined reference pressure, the predetermined low pressure (P _S2 )
And a learning control means (1a) for correcting the above.

In the present invention according to claim 3, the predetermined reference pressure is a predetermined pressure (P _S2 ) preset to the predetermined low pressure (P _S2 ).
The hydraulic control device for an automatic transmission according to claim 2, wherein the hydraulic pressure is calculated by adding _OFFSET ).

According to a fourth aspect of the present invention, the predetermined value calculated based on the running condition detecting means is a rotation change rate (ωs') at the start of rotation change of the input shaft. The hydraulic control device for an automatic transmission according to any one of 1 to 3 above.

[0009]

[0010]

[Operation] Based on the above configuration, the engagement side signal hydraulic pressure is first controlled by the servo start control based on the shift determination. The servo start control is performed by outputting a predetermined high pressure (P _S1 ) to stroke the piston (19) of the hydraulic servo (10) so that the clearance of the friction material is eliminated, and a predetermined low pressure that maintains the stroke state. It has a low pressure standby for outputting (P _S2 ) for a predetermined time. After the completion of the servo start control, the pressure is increased from a predetermined low pressure (P _S2 ) toward a target engagement pressure (P _TA ) set based on the input torque so that the hydraulic pressure is immediately before the inertia phase, for example.

Then, for example, a predetermined value calculated based on the traveling condition such as the rotation change rate (ωs') at the start of the rotation change of the input shaft (at the start of the rotation change by the gear ratio),
Either one of the predetermined low pressure (P _S2 ) and the target engagement pressure (P _TA ) is learned and corrected so as to reach the target value. At this time, when the input torque (T _T) is equal to or greater than a predetermined value, for example, when the target engagement pressure set by the input torque (P _TA) is higher than a predetermined reference value (P _S2 + P _OFFSET), the target engagement pressure However, if the input torque such as power off is less than or equal to a predetermined value, for example, the target engagement hydraulic pressure (P _TA ) is less than or equal to a predetermined reference value, the predetermined low pressure (P _S2 ) is learned and corrected. .

The reference numerals in parentheses are for comparison with the drawings, but do not limit the structure of the present invention in any way.

[0014]

According to the first aspect of the present invention, either the predetermined low pressure for servo start control or the target engagement pressure for engagement control is selected according to the input torque, and the selected predetermined low pressure or Since the learning control is performed by correcting the target engagement pressure, the target value can always be surely converged to the target value regardless of the input torque, and the shift shock and the like can be reduced by performing the appropriate learning control. When the input torque is equal to or higher than a predetermined value, the target engagement pressure is corrected, and when the input torque is equal to or lower than a predetermined value, the predetermined low pressure is corrected. By accurately correcting the predetermined low pressure, the shift can be reliably advanced, and when the input torque is equal to or higher than the predetermined value, the target engagement pressure can be corrected to perform accurate learning control without disturbance.

According to the second aspect of the present invention, the target engagement pressure is compared with a predetermined reference pressure to select either the target engagement pressure or the predetermined low pressure, and the selected predetermined low pressure or target engagement is selected. Since learning control is performed by correcting the pressure, it is possible to always reliably converge to the target value regardless of the input torque.
By performing appropriate learning control, shift shock and the like can be reduced. Further, since the predetermined low pressure and the target engagement pressure are selected by comparing the target engagement pressure set by the input torque with the predetermined reference pressure, it is easier to select the target engagement pressure required for the engagement control. And the above selection can be made accurately. Further, when the target engagement pressure is lower than the predetermined reference pressure, the shift is reliably performed by correcting the predetermined low pressure, and when the target engagement pressure is higher than the predetermined reference pressure, the target engagement pressure is corrected. Thereby, accurate learning control without disturbance can be performed.

According to the present invention of claim 3, the predetermined reference pressure is a hydraulic pressure obtained by adding a predetermined pressure to a predetermined low pressure. Therefore, when the target engagement pressure is equal to or lower than the predetermined reference pressure, the predetermined low pressure is corrected. As a result, the predetermined reference pressure is corrected together with the predetermined low pressure, and the predetermined reference pressure is learned and corrected so that the predetermined reference pressure becomes an appropriate hydraulic pressure at which gear shifting mainly based on the engagement pressure can proceed.

According to the fourth aspect of the present invention, since the rotational speed of the input shaft is constantly detected for servo start control and the like, the rotational change rate at the start of rotational change is easy and relatively accurate. It can be calculated and becomes an appropriate index for learning control, and accurate learning control can be easily performed.

[0018]

[0019]

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present automatic transmission has a large number of friction engagement elements such as clutches and brakes, and an automatic transmission in which the transmission path of a planetary gear is selected by appropriately connecting and disconnecting these friction engagement elements. A mechanism (not shown) is provided, the input shaft of the automatic transmission is connected to the engine output shaft via a torque converter, and the output shaft is connected to the drive wheels.

FIG. 1 is a block diagram showing electric system control. Reference numeral 1 is a control unit (ECU) composed of a microcomputer, which is an engine rotation sensor 2 and a throttle opening for detecting an accelerator pedal depression amount of a driver. Signals from the speed sensor 3, the input shaft rotation speed (= turbine rotation speed) of the transmission (automatic transmission mechanism), the vehicle speed (= automatic transmission output shaft rotation speed) sensor 6, and the oil temperature sensor 7. It is being input and is being output to the linear solenoid valves SLS and SLU of the hydraulic circuit. The control section 1 outputs a predetermined high pressure (P _S1 ) that strokes the piston (19) of the hydraulic servo (10) to a state immediately before the engagement side frictional engagement element generates torque capacity, and a fast fill, Servo start control means (1a) for performing servo start control having a low pressure standby for outputting a predetermined low pressure (P _S2 ) that holds the piston in a stroked state;
After the completion of the servo start control, an engagement control means (1b) for increasing the hydraulic pressure toward a target engagement pressure (P _TA ) set based on the input torque, and a predetermined value calculated based on the traveling state detection means. The predetermined low pressure (P _S2 ) and the target engagement pressure (P _S2 ) selected based on the input torque (T _T ) or the target engagement pressure (P _TA ) so that (ωs ′) becomes a preset target value. Learning control means (1) for correcting either one of P _TA
c), and a predetermined control signal is output from the control means to the linear solenoid valve SLS or SLU.

FIG. 2 is a diagram showing the outline of the hydraulic circuit.
A plurality of friction engagement elements having the two linear solenoid valves SLS and SLU and switching the transmission path of the planetary gear unit of the automatic transmission mechanism to achieve, for example, the fourth or fifth forward speed and the first reverse speed. Plural hydraulic servos 9 and 1 for connecting and disconnecting (clutch and brake).
Has 0. In addition, the linear solenoid valve S
Solenoid modulator pressure is supplied to the input ports a ₁ and a ₂ of the LS and SLU, and the control oil pressures from the output ports b ₁ and b _{2 of} these linear solenoid valves are controlled in the control oil chambers of the pressure control valves 11 and 12, respectively. It is supplied to 11a and 12a. The line pressures of the pressure control valves 11 and 12 are supplied to the input ports 11b and 12b, respectively, and the pressure regulation from the output ports 11c and 12c regulated by the control oil pressure shifts the shift valves 13 and 15, respectively. It is appropriately supplied to each hydraulic servo 9, 10.

This hydraulic circuit is for showing the basic concept, and the hydraulic servos 9 and 10 and the shift valves 13 and 15 are shown symbolically, and actually,
A large number of hydraulic servos are provided corresponding to the automatic transmission mechanism, and a large number of shift valves for switching the hydraulic pressure to these hydraulic servos are also provided. Further, as shown in the hydraulic servo 10, the hydraulic servo has a piston 19 fitted in a cylinder 16 in an oil-tight manner by an oil seal 17, and the piston 19 acts on the hydraulic chamber 20. Based on the pressure-adjusted hydraulic pressure from (3), it moves against the return spring 21 and brings the outer friction plate 22 and the inner friction member 23 into contact with each other. Although the friction plate and the friction material are shown as a clutch, it goes without saying that the same applies to a brake.

Next, a hydraulic control device which is the basis of the present invention will be described with reference to FIGS. 3, 4 and 5.

Based on the signals from the throttle opening sensor 3 and the vehicle speed sensor 6 based on the driver's operation of the accelerator pedal, a shift determination, for example, an upshift determination of 2 → 3 shift is made based on a shift map in the control unit 1. Then, after a lapse of a predetermined time for preprocessing such as operation of a predetermined shift valve, shift control of the engagement hydraulic pressure P _A and the release hydraulic pressure P _B is started. Note that the shift control shown in FIG. 3 indicates a state in which the driver holds the accelerator pedal in a substantially constant operation and is upshift-controlled in a power-on state in which power is transmitted from the engine to the wheels during gear shifting. . Then, a predetermined high pressure P _{S1 is applied} to the linear solenoid valve SLS (or S) so that the hydraulic pressure (engagement hydraulic pressure) P _A to the engagement side hydraulic servo becomes a predetermined pressure.
It is output to (LU) (S2). The predetermined high pressure (limit pressure) P _S1
Immediately before the piston 19 fills the hydraulic chamber 20 of the hydraulic servo and strokes (clears) the clearance of the outer friction plate 22 and the inner friction material 23, and the engagement side friction engagement element (clutch) has a torque capacity. It is set to be in a state. That is, the predetermined high pressure P _S1 becomes a fast fill, and the predetermined high pressure is held for a predetermined time t _SA .
When the predetermined time t _SA has elapsed (S3), the engagement hydraulic pressure P _A
Is swept down at a predetermined gradient [(P _S1 −P _S2 ) / t _SB ] (S4), and when the engagement hydraulic pressure P _A reaches a predetermined low pressure P _S2 (S5), the sweep down is stopped and the predetermined low pressure is reached. P
Hold in _S2 and wait (S6). The predetermined low pressure P _S2 is set to a pressure necessary and sufficient for holding the piston in a stroked state, and the predetermined low pressure P _S2 is held until the time t has passed a predetermined time t _SE (S7). From the time counting start (t = 0) to elapse of a predetermined time t _SE , that is, step S
1 to S7 are servo start control, and a predetermined low pressure P _S2 of the servo start control is learned and controlled as described later.

Then, based on a predetermined function [P _TA = f _PTA (T _T )] which changes according to the input torque T _T , immediately before the start of the rotational change of the input rotational speed N _T (just before the start of the inertia phase). The target engagement oil pressure P _TA is calculated (S8). The engagement side hydraulic pressure P _TA immediately before the start of the inertia phase is first calculated as the engagement side torque sharing torque T _A (= 1 / a) with respect to the input torque T _T.
・ T _T ; a: torque sharing ratio) is calculated, and P _TA =
(T _A / A _A ) + B _A + dP _TA [B _A ; piston stroke pressure (= spring load), A _A ; friction plate effective radius ×
The target oil pressure P _TA is calculated by [piston area × number of friction plates × friction coefficient, dP _TA ; oil pressure amount corresponding to oil pressure delay]. Then, based on the engagement hydraulic pressure P _TA immediately before the start of the inertia phase calculated according to the input torque T _T , a predetermined gradient is calculated for a predetermined time t _TA set in advance [(P _TA −
P _S2 ) / t _TA ], and the engagement side hydraulic pressure sweeps up based on the gradient (S9). By the first sweep-up having the relatively steep gradient, the engagement torque increases and the hydraulic pressure rises to the state immediately before the change of the input rotational speed, that is, the calculated target engagement hydraulic pressure P _TA. (S10). In this state, the torque carried by the engagement side clutch increases, the carrying torque of the disengagement side clutch decreases, and the gear ratio is in the state before the upshift (2nd speed) and only the torque share changes. Therefore, the target engagement hydraulic pressure P is adjusted so that the carrying torque of the engagement side clutch matches the input torque.
_TA is calculated.

The input torque T _T (= turbine torque) is obtained by linearly interpolating the throttle opening and the engine speed based on the vehicle running condition to obtain the engine torque, and then the input / output speed of the torque converter. The speed ratio is calculated from the above, the torque ratio is calculated from the speed ratio by a map, and the engine torque is multiplied by the torque ratio.

When the target engagement hydraulic pressure P _TA is reached, that is, when it is predicted that the inertia phase in which the rotational change of the input shaft rotational speed is started is predicted, the hydraulic pressure change δP.
_TA is calculated by a function [δP _TA = fδ _PTA (ωa ′)] according to a target target rotation change rate (angular acceleration dωs / dt; ωa ′) at the start of rotation change of the input shaft rotation speed N _T. (S11). That is, when k is a constant, t _aim is a target shift start time, ωa ′ is a target rotation change rate [gradient to a target rotation speed], and I is an inertia amount, the hydraulic pressure change δP _TA = [I · ωa] / [ k · t _aim ]]. Then, the sweep up is performed with a gradient according to the hydraulic pressure change δP _TA (S12). The second sweep-up is a rotation change amount ΔN from the input shaft rotation speed N _TS at the start of rotation change.
Is continued until the predetermined shift start determination rotation speed dN _S is reached (S13). The target shift start time t _aim is set as a function of the input shaft speed N _T. From the end of the servo start control (t = t _SE ) to the start of the change in the input shaft speed (ΔN = dN _S ), that is, steps S8 to _S
13 is torque phase control, that is, engagement control.

The start of the rotation change of the input shaft rotation speed N _T means that the inertia phase is entered, that is, the gear shift based on the gear ratio (2 → 3 gear shift) is started and the gear ratio corresponding to the rotation speed of the output shaft is changed. This is the state in which the change of the input shaft rotation speed has started, and is calculated from the input rotation speed sensor 5 and the vehicle speed sensor 6. It should be noted that the detection of the input shaft rotation change start by the rotation change start detection means 1a according to the present invention is not limited to the rotation change (inertia phase start) based on the gear ratio described above, and the torque described above may be detected even in the torque phase. Since the change in the rotation of the input shaft due to the change in the sharing is started, it starts.
The rotation change in the torque phase may be detected.

Further, in the present embodiment, the shift start determination rotational speed dNs capable of detecting the rotational change based on the above gear ratio.
Shift start when it detects sometimes the rotation variation detection means detects at (1a), the shift control start time t _ST (start time) of the (t = 0) from to the detection of the speed change start determining rotational speed dNs Is measured, and the rotation change amount of the input shaft at that time (angular acceleration dNs / dt; hereinafter, rotation change rate ωs ′)
Will be calculated). The rotation change rate ωs ′ is
Normally, the target rotation change rate ω _a ′ is substantially equal to the target rotation change rate ω _a ′.

Then, the engagement side hydraulic pressure change δP _I is feedback-controlled by the rotation amount change amount ΔN based on the detection of the input shaft rotation speed sensor 5, and is set up by the gradient of the δP _I ( S14). The sweep-up by δP _{I is performed} by α of the rotation change amount ΔN until the shift is completed.
_{It is} continued up to ₁ [%], for example 70 [%] (S1
5). That is, _letting N _{TS be} the input shaft rotation speed at the start of gear shifting, ΔN being the rotational change amount, g _i being the gear ratio before gear shifting, and g _{i + 1} being the gear ratio after gear shifting, [(ΔN × 100) / N _TS ( g _i −g
_{i + 1} )] becomes α ₁ [%], and so on. Until the change in input shaft speed (gear ratio) ΔN becomes α ₁ [%],
That is, steps S14 to S15 are inertia phase control.

Further, when α ₁ [%] of the rotation change amount is exceeded, different hydraulic pressure change δP _L is set by the feedback control based on the smooth input shaft rotation speed change amount ΔN,
The sweep up is performed by the gradient of δP _L (S1
6). The δP _L generally has a slightly gentler gradient than the δP _I , and the sweep-up is continued up to α ₂ [%], for example, 90 [%] of the rotational speed change amount up to near the completion of the shift (S17). The sweep-up target shift time t _I based on δP _I and δP _L is set based on a plurality of different throttle opening / vehicle speed maps selected depending on the oil temperature. The input shaft speed change (gear ratio) ΔN is α
₂ [%], that is, steps S16 to S17
It becomes the final control.

Then, when the target shift time t _I has elapsed, the clock time t _F is set (S18), and this state substantially corresponds to the state where the inertia phase has ended. Further, a relatively rapid hydraulic pressure change δP _F is set, and the hydraulic pressure is swept up sharply due to the hydraulic pressure change (S19), and is set to a time sufficient to rise from the measured time t _F to the engagement pressure. The hydraulic pressure control on the engagement side is completed after the predetermined time t _FE has elapsed (S20). The steps S18 to S20 are the completion control.

Next, the control of the disengagement hydraulic pressure P _B in the above-mentioned upshift will be described with reference to FIGS. 3 and 5. Note that FIG. 3 shows simultaneous control of engagement and release,
So-called clutch-to-clutch (specifically 2 to 3 shifts)
However, it goes without saying that the one-way clutch is used on the disengagement side and the control based on only the engagement hydraulic pressure (specifically, the 1 → 2 shift) can be similarly established.

First, in response to a gear shift command from the control unit 1, timing of the hydraulic pressure control on the disengagement side is started simultaneously with the engagement side (S2).
1), the release hydraulic pressure P _B is calculated from the input torque Tt,
The hydraulic pressure P _W corresponding to the torque carried by the disengagement side frictional engagement element (clutch) is supplied (S22). The supply of the high oil pressure P _W is on standby and held until the engagement oil pressure P _A starts the first sweep-up (start of torque phase) (t _SE ) (S23).

Then, the engagement hydraulic pressure P _A and the input torque T _T
[T _B '= f _TB (P _A , T _T )] of the release side torque T _B ' is calculated (S24), and the margin ratios S _1U and S are further calculated.
Considering _2U (T _B = S _1U × T _B '+ S _2U ), the release side torque T _B is calculated (S25). Then, the release hydraulic pressure P _B is calculated from the release side torque T _B [P _B = f _PB
(T _B )] (S26). That is, first, the torque T _A for the engagement side frictional engagement element is shared is _{[T A = A A × (} P A -B
_A )] (A _A ; effective radius x piston = area x number of sheets x friction coefficient, _BB ; piston stroke pressure), and the torque T shared by the disengagement side frictional engagement element.
_{B 'is, [T B' = (1} / b) T T - (a / b) T A]
Calculated at. In addition, here, b is a torque share on the release side, a is a torque share on the engagement side, and T _T is an input shaft torque. Then, the tie-up degree with the engagement-side frictional engagement element is set in consideration of the drive feeling by the margin ratios (tie-up degrees) S _1U and S _2U , and the release-side torque T _B becomes [T _B = S _1U × T _B '+ S _2U ]. The allowances S _1U and S _2U are arbitrarily set in accordance with the driver's feeling in a large number of throttle opening / vehicle speed maps selected depending on the difference in oil temperature. _It consists of _1U > 1.0 and S _2U > 0.0. Further, the release hydraulic pressure P _{B is} calculated from the release side torque T _B considering the margin ratio.
Is calculated by [P _B = (T _B / A _B ) + B _B ] (A _B ; Effective radius of release side friction engagement element × Piston area × Number of sheets × Friction coefficient, B _B ; Release side piston stroke Pressure).

Release hydraulic pressure P _B calculated as described above
Since the sweep down due to is dependent on the engagement hydraulic pressure P _A , there is a two-step gradient that bends at the start of the inertia phase (t _TA ) at which the input shaft speed changes, that is, the first on the engagement side. It consists of a relatively steep slope down corresponding to the sweep up, and a relatively gentle slope down corresponding to the second sweep up on the engagement side. Then, the sweep down is similar to the engagement side, and the input shaft rotation change amount ΔN
Continues until the predetermined rotation change start determination rotation speed dN _S is reached (S27). Then, the change δP _{E of the} released hydraulic pressure is set, and the sweep down is performed by the gradient due to the change of the hydraulic pressure (S2
8) The sweep down continues until the release side oil pressure P _B becomes 0 (S29), whereby the release side oil pressure control is completed.

Next, the learning correction of the shift control according to the present invention will be described with reference to FIGS. 6 to 8.

In FIG. 6 (a), the input torque is high in the power-on state or the like, so that the target engagement hydraulic pressure P _TA (see step S8) calculated based on the input torque is preset. FIG. 6 (b) is a time chart of the input side rotational speed (gear ratio) _NT with respect to the engagement side hydraulic pressure P _A and the output rotational speed when the pressure is larger than the predetermined reference pressure (P _S2 + P _OFFSET ). In a state or the like, the input torque is low, and therefore the target engagement hydraulic pressure P _TA calculated based on the input torque is smaller than the predetermined reference pressure (P _S2 + P _OFFSET ) and the engagement side hydraulic pressure P _A and the input It is a time chart of rotation speed N _T. Incidentally, if the input torque is extremely small, after setting the low standby pressure P _S2, even if an attempt increase the hydraulic pressure toward the target engagement pressure P _TA is set by the input torque, the low standby pressure P _S2 is the target engagement Since the hydraulic pressure becomes higher than the hydraulic pressure P _TA and the shift may not proceed thereafter after the shift (rotational change) is started, a predetermined hydraulic pressure P _{TAmin is} set so that the shift is surely advanced even if the input torque is low for compensation.
Is preset.

[0040] Then, as shown in FIG. 7, when the change starts in the input rotational speed N _T speed change rate ωs at (at the shift start) 'minimum target rate of change value omega' is compared to _min (S31 ). Actually, at the start of the change in input speed,
It is the time when the sensors 5 and 6 detect the shift determination rotation speed dN _S that can detect the rotation change of the gear ratio, but theoretically, the time when the rotation speed starts is the input shaft rotation speed N _TS. becomes at start of change, the speed change judgment rotation speed dN _S is a relatively small value due to accuracy of the sensor may be ignored _{(N TS ≒ N TS -dN S} ). As described above, this has the same relationship as the rotational change rate ωa ′ at the time of actual detection and the theoretical rotational change rate ωs ′.

When the rotation change rate ωs ′ is larger than the target change rate minimum value ω ′ _min , the target change rate maximum value ω ′ is further increased.
_It is compared with _max (S32). That is, the rotation change rate ωs ′ at the start of the rotation change is compared with the target rotation change rate having a predetermined width, and the target rotation change rate minimum value ω ′ _min and the maximum value ω ′ _max are as shown in FIG. , It changes depending on the throttle opening.

[0042] Then, when the rotation change rate .omega.s 'the target change rate minimum omega' _min smaller, further predetermined reference pressure, that is, the in low standby pressure P _S2 in the servo activation control predetermined pressure P
_The value obtained by adding _OFFSET (P _S2 + P _OFFSET ) is compared with the target engagement hydraulic pressure P _TA calculated based on the input torque (S33). When the rate of change in rotation ωs ′ is small and the target engagement hydraulic pressure P _TA is high, it is determined that the input torque is small and the target engagement hydraulic pressure based on the input torque delays the progress of the shift, and the process proceeds to step S34 and the target The engagement hydraulic pressure P _TA is corrected to be higher by a predetermined amount (P _TA = P _TA + dP _TA ).
When the rotation change rate ωs' is small and the target engagement hydraulic pressure P _TA is lower than the predetermined reference pressure (P _S2 + P _OFFSET ), the input torque is small and it is appropriate to learn and correct the target engagement hydraulic pressure P _TA. If it is not, the process proceeds to step S35, the low pressure standby pressure P _S2 of the servo start control is increased by a predetermined amount (P _S2 = P _S2 + dP _S2 ), and the shift is also corrected by the low pressure standby pressure P _S2 . To do.

On the other hand, the rotation change rate ωs' at the start of the rotation change
Is larger than the target change rate ω ′ _max , a predetermined reference pressure (P _S2 + P _OFFSET ) which is a value obtained by adding the predetermined hydraulic pressure P _OFFSET to the low pressure standby pressure P _S2 is further compared with the target engagement hydraulic pressure P _TA ( S36). When the rotation change rate ωs ′ is large and the target engagement hydraulic pressure P _TA is high, it is determined that the progress of the shift is too rapid (too fast) depending on the target engagement hydraulic pressure based on the input torque, and the process proceeds to step S37, The target engagement hydraulic pressure P _TA is corrected to be lowered by a predetermined amount (P _TA = P _TA + d
P _TA ). If the rotation change rate ωs ′ is large and the target engagement hydraulic pressure P _TA is low, it is determined that the input torque is small and it is not appropriate to correct the target engagement hydraulic pressure P _TA by learning, and the process proceeds to step S38. , The low pressure standby pressure P _S2 of the servo start control is reduced by a predetermined amount (P _S2 = P _S2 -dP _S2 ), and the correction is performed so that the progress of the shift becomes slow (slow).

[0044] Then, if the rotation change rate ωs at rotation change start 'minimum value omega target rotation change rate' is between the _min and maximum value omega _'max, i.e. when in the target rotational speed change rate within shifting When it is judged to be appropriate, the target hydraulic pressure P _TA and the low-pressure standby pressure P _S2 are maintained without being corrected (S3
9). That is, when the input torque is low in the power-off state or the like and the target engagement hydraulic pressure P _TA calculated by the input torque does not reach the predetermined reference pressure (P _S2 + P _OFFSET ), the target engagement hydraulic pressure P _TA
It is determined that it is inappropriate to learn and correct the low pressure standby pressure P _S2 of the servo start control, and only when the target engagement hydraulic pressure P _TA is equal to or higher than a predetermined reference pressure, the rotation change at the start of the rotation change is performed. The target engagement hydraulic pressure P _TA is learned and corrected based on the rate (shift initial rotation change rate) ωs ′, and learning control is performed so that the rotation change rate converges within the target rotation change rate. Also, the target engagement hydraulic pressure P
_{When TA} is lower than the predetermined reference pressure (P _S2 + P _OFFSET ), the low pressure standby pressure (predetermined low pressure) P _S2 is corrected, but the predetermined reference pressure is obtained by adding the predetermined pressure P _OFFSET to the low pressure standby pressure P _S2 . Since it consists of hydraulic pressure, the predetermined reference pressure is corrected together with the low pressure standby pressure. That is, when the rotation change rate is smaller than the target rotation change rate, the predetermined reference pressure also increases, and the target engagement pressure P _TA is corrected in a high state so that the gear shift progresses quickly, and the rotation change rate is set to the target. When it is larger than the rotation change rate, the predetermined reference pressure becomes low, and the target engagement pressure P _TA is corrected in a low state so that the shift proceeds slowly.

In the above-described embodiment, the target engagement hydraulic pressure P _TA calculated in step S38 is adopted as the target engagement pressure set by the input torque, but the present invention is not limited to this. It may be the actual inertia phase start hydraulic pressure by δP _TA calculated in S11, or the target engagement hydraulic pressure by the hydraulic control that is not the two-step sweep described above. The point is that it is set by the input torque after the servo start control. The target value of the hydraulic pressure increase (initial engagement value) may be set.

[Brief description of drawings]

FIG. 1 is an electrical block diagram according to the present invention.

FIG. 2 is a diagram schematically showing a hydraulic circuit according to the present invention.

FIG. 3 is a time chart showing the control signal pressures of the engagement-side hydraulic pressure and the release-side hydraulic pressure that are the basis of the present invention.

FIG. 4 is a flowchart showing engagement side hydraulic pressure control in upshift gear shifting.

FIG. 5 is a flowchart showing disengagement side hydraulic pressure control in upshift gear shifting.

6 (a) is a time chart when the target engagement pressure P _TA In the power-off state and the like is higher than a predetermined value, (b) the target engagement pressure P _TA is given by a power off state, etc. Time chart when it is lower than the value.

FIG. 7 is a flowchart showing learning control according to the present invention.

FIG. 8 is a target change rate maximum value ω ′ _max and a minimum value ω ′ _min.
FIG. 6 is a diagram showing a change in the throttle opening according to FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 control part (ECU) 1a servo start control means 1b engagement control means 1c learning control means 2-7 running condition detection means 5 input shaft rotation speed sensor 6 output shaft rotation speed sensor (vehicle speed sensor) 9, 10 hydraulic servo 19 piston dN _S , N _TS Rotation change start ωs ′ Rotation change rate P _TA Target engagement hydraulic pressure P _S1 Predetermined high pressure P _S2 Predetermined low pressure T _T Input torque SLS, SLU Pressure adjusting means

(72) Inventor Masao Saito, 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture, Aisin AW Co., Ltd. (72) Takayuki Kubo, 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture W Corporation (56) Reference JP-A-9-222164 (JP, A) JP-A-9-170654 (JP, A) JP-A-8-338519 (JP, A) JP-A-5-296332 (JP , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] 1. An input shaft to which power is input from an engine output shaft, an output shaft connected to a wheel, and a plurality of friction engagement elements for changing a power transmission path between the input shaft and the output shaft. In the hydraulic control device for the automatic transmission, which comprises: a hydraulic servo that disconnects and makes contact with these friction engagement elements, at least the engagement pressure supplied to the hydraulic servo of the friction engagement elements on the engagement side is adjusted. A pressure adjusting means, a running condition detecting means for detecting a running condition of the vehicle, and a fast outputting high predetermined pressure for stroking the piston of the hydraulic servo in a state immediately before the engagement side frictional engagement element produces torque capacity. A fill, and a low pressure standby that outputs a predetermined low pressure that holds the piston in a stroked state,
A servo start control means for performing servo start control, and an engagement control means for increasing the hydraulic pressure toward a target engagement pressure set based on the input torque after the servo start control is completed; The input torque is set to a predetermined value so that the predetermined value calculated on the basis of the predetermined target value.
Is greater than the value of, the target engagement pressure is corrected and the input pressure
A hydraulic control device for an automatic transmission , comprising: learning control means for correcting the predetermined low pressure when the torque is below a predetermined value . 2. An input shaft to which power is input from an engine output shaft, an output shaft connected to wheels, and a plurality of friction engagement elements for changing a power transmission path between the input shaft and the output shaft. In the hydraulic control device for the automatic transmission, which comprises: a hydraulic servo that disconnects and makes contact with these friction engagement elements, at least the engagement pressure supplied to the hydraulic servo of the friction engagement elements on the engagement side is adjusted. A pressure adjusting means, a running condition detecting means for detecting a running condition of the vehicle, and a fast outputting high predetermined pressure for stroking the piston of the hydraulic servo in a state immediately before the engagement side frictional engagement element produces torque capacity. A fill, and a low pressure standby that outputs a predetermined low pressure that holds the piston in a stroked state,
A servo start control means for performing servo start control, and an engagement control means for increasing the hydraulic pressure toward a target engagement pressure set based on the input torque after the servo start control is completed; When the target engagement pressure is higher than the predetermined reference pressure so that the predetermined value calculated based on the preset target value, the target engagement pressure is corrected and the target engagement pressure is adjusted to the predetermined reference pressure. If it is lower, a learning control means for correcting the predetermined low pressure, and a hydraulic control device for an automatic transmission, comprising: 3. The hydraulic control device for an automatic transmission according to claim 2, wherein the predetermined reference pressure is a hydraulic pressure calculated by adding a predetermined pressure set in advance to the predetermined low pressure. 4. The hydraulic control of the automatic transmission according to claim 1, wherein the predetermined value calculated based on the traveling condition detection means is a rotation change rate at the start of rotation change of the input shaft. apparatus.