JP3427671B2 - Transmission 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 device for an automatic transmission mounted on an automobile, and more particularly to a servo control for learning, for example, a shift control device for changing a fast fill time.

[0002]

2. Description of the Related Art Generally, an automatic transmission supplies hydraulic pressure to a hydraulic servo for a predetermined friction engagement element (clutch or brake) based on a gear shift judgment from a control unit, and hydraulic servos for other friction engagement elements. The hydraulic pressure is released to switch the transmission path of the multistage speed change gear mechanism to change the speed. At this time, the engagement-side hydraulic servo or the release-side hydraulic servo hydraulic pressure is adjusted by a pressure adjusting means such as a linear solenoid valve to reduce shift shock and smoothly shift.

However, even in this case, both the disengagement side and the engagement side frictional engagement elements are in the engaged state due to the initial variation due to individual difference of each product and the variation of the linear solenoid valve etc. due to aging. (Overlap state)
May cause tie-up, or both the disengagement-side and engagement-side frictional engagement elements may be in a disengaged state (underlap state), causing engine upswing.

[0004] Conventionally, in gear shifting by so-called clutch grip change, which releases the disengagement side frictional engagement element together with the engagement of the engagement side frictional engagement element, the overlap of the engagement side and the disengagement side frictional engagement element or In order to prevent the output shaft torque from decreasing due to engine blow-up or tie-up due to an inappropriate degree of underlap, engine blow-up is detected and the amount of blow-up falls within a predetermined range. A shift control device for controlling the hydraulic pressure has been proposed (see Japanese Patent Laid-Open No. 6-341535).

This is for correcting the pressure adjustment of the hydraulic pressure for the frictional engagement element on the front side of the gear shift with a correction amount set according to the maximum upstroke amount of the engine.
In the 2 → 3 shift, the duty ratio of the linear solenoid valve that adjusts the hydraulic pressure of the friction engagement element (third brake B ₃ ) that is released at the third speed is set to the maximum fluctuation range of the engine rotation until the inertia phase starts. The value is corrected by the correction value that is set as the blowing amount.

[0006]

SUMMARY OF THE INVENTION The above shift control device is
During upshifting, the pressure adjustment of the hydraulic pressure on the release side is corrected, the degree of decrease in the release pressure is changed, and an overpressure occurs with the hydraulic pressure of the engagement side frictional engagement element that is set to a predetermined increase state in advance. The degree of lap or underlap is adjusted.

However, the engine blow-up or tie-up due to the degree of overlap or underlap is not the degree of decrease (gradient) of the hydraulic pressure on the release side as described above, but rather the frictional engagement on the engagement side and the release side. The start timing of the element has a greater influence, and with the correction of the disengagement side hydraulic pressure as described above, it was not always possible to properly adjust depending on the state of the engagement side hydraulic pressure.

Therefore, the present invention supplies the hydraulic pressure to the hydraulic servos of the engagement side friction engagement elements to stroke the piston and immediately before the start of torque transmission, before the gripping of the engagement side and release side friction engagement elements is changed. It is possible to provide a shift control device for an automatic transmission, which performs learning control of servo start control for controlling so that the state can be changed to prevent engine blow-up and tie-up, thereby improving shift feeling. It is intended.

[0009]

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, wherein the first frictional engagement element of the plurality of frictional engagement elements is engaged and the second frictional engagement element is released to achieve a shift to a predetermined shift stage. Prior to this, an automatic transmission is provided, in which the first frictional engagement element is subjected to servo start control to supply a hydraulic pressure having a predetermined characteristic to its hydraulic servo to stroke the piston (19) to bring the piston (19) into a state immediately before torque transmission. In the shift control device, the pressure adjusting means (SLS or SLU) for adjusting the engagement pressure supplied to at least the hydraulic servo of the first friction engagement element, and a predetermined time within the control time of the servo start control. Detecting means (1a) for detecting a tie-up that occurs in the servo start control means (1b) for correcting the predetermined characteristic in the servo start control based on a correction amount corresponding to a detection value of the detecting means.
And a gear shift control device for an automatic transmission.

According to a second aspect of the present invention, in the servo start control, a fast fill for supplying a predetermined high pressure (P _S1 ) to a hydraulic servo and a sweep down of the predetermined high pressure toward a predetermined low pressure (P _S2 ). Control and holding at the predetermined low pressure, and the servo start control time (t _SE )
Is substantially constant time, and the servo start control means is
The shift control device for an automatic transmission according to claim 1, which is a fast fill control means (1b) for controlling the fast fill.

The present invention according to claim 3 provides the shift control device for an automatic transmission according to claim 2, wherein the fast fill control means corrects the fast fill time (t _SA ).

According to a fourth aspect of the present invention, the shift to the predetermined shift stage is upshift, and the detection value of the detecting means is calculated based on the signal of the sensor (5) for detecting the rotation of the input shaft. The shift control device for an automatic transmission according to claim 1, 2 or 3, wherein the input rotation acceleration (α) is set.

[0013]

According to a fifth aspect of the present invention, the detection means detects a minus protrusion of the input rotational acceleration (α) that occurs during a predetermined time within the control time (t _SE ) of the servo start control time. The tie-up is thus determined, and the correction amount (A, B) of the fast fill control means is learned according to the amount (a, b) of the input rotational acceleration.
The shift control device for the automatic transmission described above.

[Operation] Based on the above construction, when the detection means (1a) detects a tie-up in the direction of the input rotational acceleration (α), for example, the servo start control means (1b) detects the hydraulic pressure supplied to the hydraulic servo. Change / correct predetermined characteristics. That is, the servo start control includes a fast fill for supplying a predetermined high pressure (P _S1 ), a control for sweeping down from the predetermined high pressure to a predetermined low pressure (P _S2 ), and a control for maintaining the predetermined low pressure. The balance of each control is changed in the state where the servo start control time (t _SE ) of the whole is constant. For example, the fast fill time (t _SA ) is changed within a constant servo start control time (t _SE ) and the waiting time (t _SB ) is also changed accordingly.

As an example, when the input rotational acceleration (α) protrudes in the negative direction, it is determined that tie-up has occurred, and the correction amount (-A) (-B) is used as a fast value in accordance with the acceleration amount (a) (b). Learn and correct fill time (t _SA ).

Thus, at the time of tie-up, the fast fill time is controlled so as to be shortened, and the servo start-up time is corrected to be appropriate.

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

[0019]

According to the first aspect of the present invention, even if tie-up occurs due to variations due to individual differences between products and aging, a predetermined hydraulic pressure characteristic in the servo start control is corrected, so that when gripping is changed. Since the increase timing of the torque capacity of the engagement side friction engagement element can be controlled with good convergence and accurately, the timing with the release side friction engagement element can be accurately adjusted to facilitate the grip change during the gear shift. The shift feeling can be improved. Further, since the tie-up that occurs during a predetermined time within the servo activation control time is detected, it is possible to eliminate a disturbance that occurs outside the predetermined time, for example, due to a step on the road surface, and accurately suppress the tie-up.

According to the second aspect of the present invention, by correcting the fast fill for supplying a predetermined high pressure to the hydraulic servo, it is possible to easily and accurately adjust the grip timing during the gear shift.

According to the third aspect of the present invention, since the fast fill time is corrected, the engaging side timing is controlled by a time control that is easy and highly accurate, and has a highly reliable and inexpensive structure. The shift feeling can be improved.

According to the fourth aspect of the present invention, since tie-up or engine blowing is detected by the input rotational acceleration during upshift gear shifting, the input shaft rotational speed sensor is sufficient, and it is inexpensive and reliable without using a special sensor. Various detections can be performed.

[0023]

According to the fifth aspect of the present invention, since the protrusion of the input rotational acceleration in the negative direction generated during the predetermined time within the servo start control time is detected and the tie-up is determined, the input occurring outside the predetermined time is detected. Tie-up can be accurately suppressed by eliminating the rotational acceleration, for example, a disturbance due to a step on the road surface.

[0025]

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 unit 1 controls the servo start based on a tie-up engine blowing detection means 1a for detecting the input rotational acceleration α based on a signal from the input shaft rotation speed sensor 5 and a correction amount corresponding to the detection value of the detection means. And a servo start control means 1b for learning and correcting a predetermined hydraulic pressure characteristic of the servo start control means (fast fill control means 1
The predetermined control signal based on the fast fill time corrected by b) is the linear solenoid valve SLS or SLU.
Output to.

FIG. 2 is a diagram showing an 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, referring to FIGS. 3 and 4, the control oil pressure for upshifting when the accelerator pedal is depressed in a substantially constant state (power-on state) will be described.

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 side hydraulic pressure P _A and the disengagement side hydraulic pressure P _B is started. Simultaneously with the start of the shift, a predetermined signal is sent to the linear solenoid valve SLS (or SL) so that the hydraulic pressure to the hydraulic servo on the engagement side (engagement side hydraulic pressure) P _A becomes a predetermined high pressure P _S1.
U). The predetermined high pressure (fast fill pressure) P _S1
Is set to the hydraulic pressure required to fill the hydraulic chamber 20 of the hydraulic servo (fast fill), and is held for a predetermined time t _SA . When the predetermined time t _SA has elapsed, the engagement hydraulic pressure P _A
Is swept down at a predetermined gradient dP, and when the engagement hydraulic pressure P _A becomes a predetermined low pressure P _S2 , the sweep down is stopped,
The predetermined low pressure P _S2 is maintained. The predetermined low pressure P _S2 is set to a pressure that is equal to or higher than the servo starting pressure and does not cause a rotation change of the input shaft, and the predetermined low pressure P _S2 is held until the time count reaches a predetermined time t _SE . This state is piston 1
9 is a servo start control in which the friction plate 22 and the friction material 23 are stroked (backlashed) so as to come into contact with each other, and the engagement side friction engagement element is held in a state immediately before having a torque capacity. A preset predetermined time t _{SE including a} fill time t _SA and a standby time t _SB for sweeping down and maintaining at a predetermined low pressure is continued. On the other hand, the release side hydraulic pressure P _B is the engagement pressure P _{K such as the} clutch holding pressure.
Hold for a predetermined time t _SE .

When the predetermined time t _SE has elapsed, the disengagement hydraulic pressure P _B decreases to the hydraulic pressure P _{W at the} last position where the friction engagement element has the torque capacity, and the engagement hydraulic pressure P _A has a predetermined gradient. And the sweep-up, and the hydraulic pressure on the release side sweeps down at a predetermined gradient. As a result, the torque capacity of the engagement-side friction engagement element increases as the hydraulic pressure rises, but in this state, the engagement-side friction engagement element does not slip and cause a rotational change, and Only the sharing becomes a torque phase that changes.

In the upshift, the engagement-side and release-side hydraulic pressures P _A and P _B in the torque phase are closer to the target hydraulic pressure immediately before the change of the input shaft speed. The sweep-up control is performed, and the release-side hydraulic pressure is controlled according to the engagement-side hydraulic pressure. Specifically, Japanese Patent Application No. 7-330895 and Japanese Patent Application No. 8-1 already proposed by the applicant.
The control described in No. 09787 (both unpublished at the time of filing this application) is preferable.

Then, as the torque capacity of the engagement side frictional engagement element increases, the torque capacity of the disengagement side frictional engagement element decreases, the input shaft rotational speed N _T begins to decrease, and the inertia phase is entered. In the inertia phase, the engagement side hydraulic pressure P _A
Is feedback-controlled by the rotation change amount based on the detection of the input shaft rotation speed sensor 5, and the disengagement side oil pressure P _B is controlled in accordance with the engagement side oil pressure, so that the engagement side friction engagement element is completely When they are engaged and the input shaft speed N _T reaches the rotation ratio of the latter stage of the gear shift, the hydraulic pressure on the engagement side rises to the line pressure and the gear shift ends.

Next, the fast fill learning control in the servo starting control, which is the main part of the present invention, will be described.
Description will be given along the flow chart shown in FIG.

When the upshift gear shift control is started, the servo start control is immediately started. First, the sum of an initial value X (msec) set in advance and a learned value Y (msec) which will be described later. Thus, the engagement side fast fill time t _SA (= X + Y) is set (S1). Then,
The predetermined time t _SE of the servo start control is set in consideration of the delay time of the hydraulic pressure (S2), and the predetermined pressure (limit pressure) P _{S1 of the} fast fill, the predetermined low pressure P _S2 , and the predetermined low pressure to the predetermined low pressure. The sweep down gradient dP to is set (S3). Further, based on the input shaft rotation speed sensor 5, the acceleration α of the current input rotation speed, that is, the fluctuation rate of the input rotation speed is calculated and stored (S4). The storage of the acceleration α is a value based on the detection value of the input shaft rotation speed sensor 5 during a predetermined predetermined time, for example, during a servo start control or a fixed time after the initial value X has elapsed. This reduces the probability that an acceleration disturbance due to the tire crossing a step on the road surface or the like will enter. Then, the control hydraulic pressure based on the set times t _SA , t _SE and the hydraulic pressures P _S1 , P _S2 , and dP is output from the linear solenoid valve SLS or SLU (S5), whereby the servo start control ends.

Then, based on the stored acceleration α,
If it is on the negative side, it is determined to be tie-up, and if it is on the positive side and is equal to or greater than the predetermined lower limit value L, it is determined to be engine blowing, and the tie-up amount and blowing amount are calculated based on the size (S6). Then, the learning value Y for setting the engagement side fast fill time t _SA (see S1) from the tie-up amount and the blowing amount according to the map of FIG. 5 (b).
To calculate. Since the servo start control time t _SE is a fixed time, the standby time t _SA is also changed based on the correction of the fast fill time t _SA .

FIG. 3 is a view showing a tie-up, in which the engagement-side hydraulic pressure rises too early and the release-side frictional engagement element has sufficient torque capacity while the engagement-side frictional engagement is performed. This occurs when the torque capacity of the element becomes large and becomes in the overlap state, and the input rotation acceleration value α instantaneously projects in the negative direction at a predetermined amount or more. At this time, the time during which the piston does not divide the stroke in the servo start control is set, and the maximum value of the input rotational acceleration α within the time is detected / calculated to reduce the probability of disturbance. Also,
The protrusion in the plus direction following the protrusion in the minus direction of the acceleration is a rebound that is inevitably generated during tie-up and is not detected as the acceleration.

When the protrusion amount in the minus direction of the acceleration α is small (a), a small tie-up amount is calculated and a small learning value [-A] (Y corresponding to the tie-up amount is calculated.
= -A) is calculated. Thus, in the next upshift, the fast fill time t _SA is a value (t _SA = X−) obtained by adding the learning value [−A] to the initial value X.
A) It is set as [msec]. When the amount of protrusion of the acceleration α in the negative direction is large (b), a large tie-up amount is calculated and a large learning value [−B] (Y = −B) corresponding to the tie-up amount is calculated. Accordingly, at the next upshift, the fast fill time t _SA is set as a value (t _SA = X−B) [msec] obtained by adding the learning value [−B] to the initial value X.

As a result, the fast fill time t _SA is corrected and shortened by the learning value based on the tie-up amount,
The servo activation amount in the servo activation control becomes small.
As a result, the amount of overlap between the release side and engagement side frictional engagement elements is reduced, and the tie-up is reduced or eliminated.

FIG. 4 is a view showing the engine blowing. In the engine blowing, even if the engagement side hydraulic pressure rises too late and the torque capacity of the disengagement side friction engagement element becomes sufficiently small, the engagement side friction is generated. This occurs when the torque capacity of the engagement element is not sufficiently increased (underlap state), and the input rotational acceleration α projects in the plus direction from the lower limit L that is equal to or greater than the predetermined amount l. The increase in the acceleration α occurs when the torque sharing of the engagement side and the release side frictional engagement elements does not go well or due to individual variations, but in this case, the blowing amount is not so large.
In general, the acceleration α does not exceed the lower limit value L. Therefore, only when the acceleration lower limit value L is exceeded, it is determined that the timing of the engagement side and release side frictional engagement elements is defective, and the correction is performed by learning the fast fill time. I do.

During the servo start control (t <t _SE ), or within a predetermined time after the lapse of the acceleration, the acceleration α of a predetermined lower limit value L or more in the plus direction
Appears, the engine is judged to be blown, and the blow amount is calculated from the amount of acceleration α. When the acceleration is small (c), the calculated learning value [C] (Y = C) is also small,
The fast fill time t _SA is set by adding the learning value [C] to the initial value X (t _SA = X + C). Also,
When the acceleration is large (d), the calculated learning value [D]
(Y = D) is also large, and the fast fill time t _SA is set by adding the learning value [D] to the initial value X (t _SA =
X + D).

As a result, when the engine is blown, the fast fill time t _SA is corrected to be long according to the blowing amount. As a result, as the engagement-side hydraulic pressure rises, the engagement-side friction engagement element quickly has a relatively large torque capacity, and the underlap amount of the engagement-side and release-side friction engagement elements is reduced to blow the engine. Reduce or eliminate.

In the above-described embodiment, the tie-up amount and the engine blowing amount are obtained from the input rotational acceleration α based on the input shaft rotational speed sensor 5, but the present invention is not limited to this, and is calculated from the vehicle speed sensor 6 and the gear ratio. Alternatively, it may be obtained by the difference between the output side rotation speed and the input side rotation speed of the input shaft rotation speed sensor 5. Further, in the above-described embodiment, the servo start control is changed and corrected by the fast fill time t _SA , but the fast fill pressure P _S1 may be changed and controlled, and the invention is not limited to this. _{In the} servo start control consisting of _SE ), the balance between the fast fill time t _SA and the standby time t _SB may be changed and controlled. Further, although the above embodiment has been described for the upshift, it can be applied to the downshift by changing the grip.

[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 diagram showing a time chart during tie-up.

FIG. 4 is a view showing a time chart when the engine is blown.

5A is a flowchart showing an embodiment of the present invention, and FIG. 5B is a diagram showing a relationship between a tie-up amount, a blowing amount, and a learning value.

[Explanation of symbols]

1 Control unit 1a Tie-up engine blow detection means 1b Servo start (fast fill control) means 5 Input shaft speed sensor 9, 10 Hydraulic servo SLS, SLU Pressure adjusting means (linear solenoid valve) α Input rotational acceleration P _A engagement Side oil pressure P _B Release oil pressure P _S1 High pressure P _S2 Low pressure t _SE Servo start control time t _SA Fast fill time Y Learning value

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Suzuki, 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture, Aisin AW Co., Ltd. (72) Hiroshi Tsutsui, 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture Aisin・ AW Co., Ltd. (56) Reference JP-A-8-334171 (JP, A) JP-A-5-296332 (JP, A) JP-A-6-341535 (JP, A) JP-A-5- 296323 (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 (5)

(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. And a hydraulic servo for actuating / disconnecting these friction engagement elements to engage a first friction engagement element of the plurality of friction engagement elements and a second friction engagement element. Prior to achieving the shift to the predetermined shift stage by releasing the hydraulic pressure, the first frictional engagement element is supplied with the hydraulic pressure to its hydraulic servo with a predetermined characteristic to stroke the piston to the state immediately before the torque transmission. In a shift control device for an automatic transmission, which performs a servo start control, a pressure adjusting means for adjusting at least an engagement pressure supplied to a hydraulic servo of the first friction engagement element, and a control time for the servo start control. <br/> data generated during a predetermined time internal An automatic transmission comprising: a detection unit that detects an up-shift; and a servo start control unit that corrects the predetermined characteristic in the servo start control based on a correction amount corresponding to a detection value of the detection unit. Shift control device. 2. The servo start control includes a fast fill for supplying a predetermined high pressure to a hydraulic servo, a control for sweeping down the predetermined high pressure toward a predetermined low pressure, and a control for holding the predetermined low pressure. 2. The shift control device for an automatic transmission according to claim 1, wherein the servo start control time is substantially constant, and the servo start control means is a fast fill control means for controlling the fast fill. 3. The shift control device for an automatic transmission according to claim 2, wherein the fast fill control means corrects a fast fill time. 4. The shift to the predetermined shift stage is an upshift, and the detection value of the detection means is an input rotational acceleration calculated based on a signal of a sensor that detects the rotation of the input shaft. A shift control device for an automatic transmission according to 1, 2, or 3. 5. The input means determines a tie-up by detecting a protrusion in the negative direction of the input rotational acceleration that occurs during a predetermined time within the control time of the servo start control, and the input means detects the tie-up. The shift control device for an automatic transmission according to claim 4, wherein the correction amount of the fast fill control means is learned according to the amount of rotational acceleration.