JPH0696376B2 - Shift control method for automatic transmission for vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission for a vehicle, and more particularly to a shift control method for preventing torque fluctuation during shifting to improve shift feeling. .

(Prior Art) An automatic transmission for a vehicle sends hydraulic pressure to hydraulic friction engagement elements such as a clutch and a brake, and these friction engagement elements are
Depending on the driving condition of the vehicle, select by engaging with a predetermined rotating element such as a rotating drum or gear, and change the gear ratio between the input shaft and the output shaft (shifting) to best suit the characteristics of the engine. Is done automatically.

An example of a general vehicular automatic transmission will be described with reference to FIG. 2 showing a schematic structure thereof. A crankshaft 4 of an engine 2 which is a power source of a vehicle is a pump 8 of a torque converter 6.
Is directly connected to.

The torque converter 6 includes a pump 8, a turbine 10, and a stator.
12 has a one-way clutch 14, the stator 12 is coupled to the case 16 via the one-way clutch 14, and the one-way clutch 14 causes the stator 12 to rotate in the same direction as the crankshaft 4, but allows rotation in the opposite direction. It is a structure that is not used.

The torque transmitted to the turbine 10 is transmitted by an input shaft 20 integrated with the turbine 10 to a gear transmission 22 that is disposed at the rear of the turbine 10 and that achieves four forward gears and one reverse gear.

This transmission 22 is composed of three sets of clutches 24, 26, 28, two sets of brakes 30, 32, one set of one-way clutch 34 and one set of Ravigneaux type planetary gear mechanism 36. The planetary gear mechanism 36 is composed of a ring gear 38, a long pinion gear 40, a short pinion gear 42, a front sun gear 44, a rear sun gear 46, both pinion gears 40 and 42 rotatably supported, and a carrier 48 which is also rotatable. Is connected to the output shaft 50, and the front sun gear 44 is connected to the input shaft via the kickdown drum 52 and the front clutch 24.
The rear sun gear 46 is connected to the input shaft 20 via the rear clutch 26, and the carrier 48 is connected to the case 16 via the low reverse brake 32 and the one-way clutch 34 which are functionally arranged in parallel. The transmission 22 is connected to the input shaft 20 via a fourth speed clutch (end clutch) 28 arranged at the rear end of the transmission 22. The kick down drum 52 can be fixedly connected to the case 16 by the kick down brake 30.

Then, the torque passing through the planetary gear mechanism 36 is transmitted from the transfer drive gear 60 fixed to the output shaft 50 to the driven gear 64 via the idle gear 62, and the driven gear 64 is further transmitted.
Transfer shaft 66 fixed to 64, helical gear
A differential gear unit in which a drive shaft 70 of drive wheels is connected via 68
Propagated to 72.

Each of the above-mentioned clutches and brakes, which are frictional engagement elements, is constituted by a frictional engagement device including an engagement piston device or a servo device, and is connected to the pump 8 of the torque converter 6 and driven by the engine 2. It is operated by the hydraulic pressure generated by an oil pump (not shown). The hydraulic pressure from this oil pump is selectively supplied to each clutch and brake according to the operating states detected by various operating state detecting devices by a hydraulic control device described later, and depending on the combination of the operation of each clutch and brake. A shift speed of four forward gears and one reverse gear is achieved, and the detailed structure and operation thereof are as disclosed in Japanese Patent Laid-Open No. 58-46258.

Here, for example, in the first gear speed other than the fixed range of the first gear (so-called D range), the front clutch 24
The fourth-speed clutch 28 is not connected, the kick-down brake 30 and the low reverse brake 32 are released, the rear clutch 26 is connected, and the one-way clutch 34 is in a functioning state.
In this case, the upshift to the second speed is achieved only by connecting the kick down brake, and the one-way clutch 34 does not function.

A hydraulic control circuit that realizes this transmission system is shown in FIG. 3, and only the portion necessary for controlling the operation of the kick down brake 30 is shown in FIG. Kick down brake
A 1-2 shift valve 81 is connected to a kick-down servo 80 for controlling the operation of 30 through an oil passage 82. The 1-2 shift valve 81 includes a hydraulic control valve 83 and a shift control valve 84. They are connected via oil passages 85 and 86, respectively.

A pair of solenoid valves 87, 88 that control the operation of the shift control valve 84.
Both open the oil passages 89 and 90, the shift control valve 8
The spool 91 at the center of 4 is displaced to the left in FIG.
6 is communicated with the oil discharge port EX of the shift control valve 84, 1-2
The spool 92 of the shift valve 81 is in the state of being displaced to the left end in FIG. As a result, the oil passage 82 communicates with the oil discharge port EX of the 1-2 shift valve 81, and the piston 94 is returned to the right side in FIG. 3 by the spring force of the compression coil spring 93 of the kickdown servo 80. The engagement of the kick down brake 30 with the kick down drum 52 is released. Also hydraulic control valve
Of the two oil passages 95 and 96 connected to 83, the duty ratio of the solenoid valve 98 attached to one oil passage 95 and duty-controlled by the electronic control unit (controller) 97 is set to 100%. The hydraulic pressure 95 does not have the hydraulic pressure that overcomes the return spring of the hydraulic control valve 83. Therefore, the spool 99 of the hydraulic control valve 83 is displaced to the left side in FIG.
95 communicates with the oil discharge port EX of the hydraulic control valve 83.

When the upshift from this state to the second speed is performed, the electronic control unit 97 operates one solenoid valve 87 to close the oil passage 89 depending on the running condition of the vehicle, so that the center spool 91 in FIG. Displaced to the right, pressure oil from the oil pump (hereinafter referred to as line pressure) is sent from the oil passage 100 connected to the shift control valve 84 to the 1-2 shift valve 81 through the oil passage 86. To be done. Therefore, the spool 92 of the 1-2 shift valve 81
3 is displaced to the right end in FIG. 3 so that the oil passages 82 and 85 communicate with each other through the 1-2 shift valve 81. On the other hand, since the duty ratio of the solenoid valve 98 is reduced by the electronic control unit 97, the oil pressure in the oil passage 95 increases in accordance with the decrease in the duty ratio, and this increased oil pressure acts on the spool 99. This makes spool 99
Is displaced to the right in FIG. 3, the line pressure from the oil passage 96 is reduced by the hydraulic control valve 83 according to the duty ratio, and
Supplied to 85. After that, the hydraulic pressure adjusted to a value according to the duty ratio is supplied to the kickdown servo 80 through the oil passages 85 and 82, and the piston 94 is stroked to the left side in FIG. The kickdown drum 52 is tightened.

By the way, if the change characteristic of the feed hydraulic pressure to the friction engagement element is inappropriate at all the shift speeds including the shift speed from the 1st speed to the 2nd speed, the friction engagement element suddenly engages. As a result, a gear shift shock may occur, or the frictional engagement element may be excessively slipped to deteriorate the frictional engagement element. Therefore, for example, in the shift speed from the first speed to the second speed, the duty ratio of the solenoid valve 89 that controls the change characteristic of the hydraulic pressure supplied to the kickdown servo 80 is attached to the piston 94 as shown in FIG. Japanese Patent Application No. 60-180794 proposes that control is performed by the following method in correspondence with the operating stroke position of the piston 94 detected by the piston stroke sensor 101 such as a potentiometer.

That is, the shift control method proposed according to the operation stroke position of the piston 94 shown in FIG. 1 (c) (operation stroke range of the piston 94 is between the partial pressure ratio of the piston stroke sensor 101 of k ₃ to k ₂₎ Then, the duty ratio of the solenoid valve 98 is changed by an electric command from the electronic control unit 97 as shown in FIG. 7A. As shown in FIG. Stroke to and reach a preset preset position just before engagement {k _2- (90/80) × 0.8} by an electrical command to set the duty ratio to 40% as shown in (a) of the figure. When the piston 94 reaches the above-mentioned predetermined position by setting a high hydraulic pressure to the kickdown servo 80, the hydraulic pressure by the electric command (electric command hydraulic pressure)
, Once lowered to a value suitable for gear shift shock-free,
The duty ratio is gradually decreased again at a ratio β according to the engine operating state determined by the throttle opening degree, the vehicle speed, etc. ((a) in the figure), and the hydraulic pressure is gradually increased. Then, it is determined that the gear shift has started when the relationship of Nt ≦ No × 2.846 is established between the rotation speed Nt of the turbine 10 and the rotation speed No of the transfer drive gear 60, and after the gear shift is started, until the gear shift is completed, That is, until the relation of Nt ≦ No × 1.581 is established, the actual rotation speed change rate ωt is set so that the actual rotation speed change rate ωt of the turbine 10 becomes the target change rate ωs set according to the throttle opening θt. The duty ratio is corrected by the correction gain set according to the deviation Δω of the target change rate ωs, and the solenoid valve 98 is operated by the corrected duty ratio to feedback control the hydraulic pressure acting on the piston 94.

(Problems to be Solved by the Invention) However, in the above-described shift control method, the duty ratio is gradually reduced by the ratio β immediately before the shift is started, and as a result, the hydraulic pressure is gradually increased and the actual rotation speed change rate ωt of the turbine 10 is increased. Shows a small value, the feedback control is started immediately after the shift is started, and the duty ratio is corrected by the correction gain set according to the deviation Δω between the actual rotation speed change rate ωt and the target change rate ωs. When the deviation Δω between the rotational speed change rate ωt (see the solid line in FIG. 1 (f)) and the target change rate ωs (see the dashed line in FIG. 1 (f)) is large, the duty ratio is suddenly corrected to a small value. As a result (see the broken line in FIG. 1A), as a result, a sharp rise in hydraulic pressure occurs as shown by the broken line in FIG. 1B, and the pressing force of the kickdown drum 52 increases rapidly (see FIG. (See the broken line in (d)), As shown by the broken line in FIG. 1 (e), a torque wave is generated, which causes an unpleasant shift shock to the occupant.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a shift control method for an automatic transmission for a vehicle that prevents shift shock in feedback control at the start of shift.

(Means for Solving the Problems) In order to solve the above problems, according to the present invention, an input shaft to which the rotational power of the engine is input, an output shaft for outputting the rotational power to the drive wheels, and Selecting a predetermined rotating element among the plurality of rotating elements which operates by hydraulic pressure and a plurality of rotating elements that shift the rotation of an input shaft to transmit the rotational power to the output shaft, and which is operated by hydraulic pressure. A gear shift of an automatic transmission for a vehicle comprising a friction engagement element for switching a gear ratio between the input shaft and the output shaft by means of an electric-hydraulic converter for electrically controlling a hydraulic pressure supplied to the friction engagement element. Detecting the actual rotation speed change rate of the rotating element, and converting the drive signal corrected by a correction gain according to the deviation between the detected actual rotation speed change rate and a preset target change rate to the electric / hydraulic conversion. Supply to the container and In a shift control method for feedback controlling the hydraulic pressure to the element, the correction gain is changed to a small value when the deviation is larger than a predetermined value, and the drive signal is corrected by the changed correction gain. A shift control method for an automatic transmission is provided.

Further, according to a second aspect of the present invention, there is provided a shift control method for an automatic transmission for a vehicle, wherein an input shaft to which rotational power of an engine is input, an output shaft for outputting rotational power to driving wheels, and a rotation of the input shaft are shifted. And a plurality of rotating elements for transmitting the rotational power to the output shaft and hydraulically operated, and by selecting a predetermined rotating element among the plurality of rotating elements according to an engine operating state, the input shaft and the While the automatic transmission for a vehicle comprises a frictional engagement element that switches the gear ratio between the output shafts and an electro-hydraulic converter that electrically controls the hydraulic pressure supplied to the frictional engagement element, the rotating element The actual rotation speed change rate of is detected, and the drive signal corrected by the correction gain according to the deviation between the detected actual rotation speed change rate and the preset target change rate is supplied to the electric-hydraulic converter, The hydraulic pressure to the rotating element is In shift control method for Dobakku control, over a predetermined time period from the start of the feedback control, to change the modified gain to a small value, characterized by modifying said drive signals in a modified gain to the change.

(Operation) When the deviation at the time of starting the feedback control is larger than the predetermined value, if the correction gain is changed to a small value, the hydraulic pressure supplied to the friction engagement element does not increase sharply and the engagement of the friction engagement element is gentle. The shift shock is prevented. Further, the period in which the deviation at the start of the feedback control is larger than the predetermined value is substantially equal to the fixed time from the start of the feedback control or the period required for the rotational speed of the rotating element to change by the predetermined number, so the deviation is larger than the predetermined value. Instead of determining whether or not the feedback gain is changed to a small value over a predetermined period from the start of the feedback control, a rapid increase in hydraulic pressure is prevented by the same operation as the first invention, The friction engagement elements are gently engaged to prevent shift shock.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

A shift control method for an automatic transmission for a vehicle according to the present invention controls a duty ratio of a solenoid valve 98 by a method described later by an electronic control unit, and thus a piston 94 of a kick-down servo 80.
It is novel in that feedback control is performed on the hydraulic pressure that acts on the shift hydraulic control device embodying the present invention, and is substantially the same as the shift hydraulic control device shown in FIG. 3 except for the electronic control device 97 described above. Since it does not change at all, its explanation is omitted. In addition to the piston stroke sensor 101 described above, the electronic control unit 97 includes a throttle opening sensor 200 for detecting the throttle opening θt and a rotational speed N of the turbine 10.
t and a rotational speed sensor 201 that detects the rotational speed (rotational speed of the output shaft) No of the transfer drive gear 60, and other control parameters such as engine rotational speed, engine output torque, engine temperature, and vehicle speed. 20
2 are electrically connected, and the detection signals detected by the sensors 200 to 202 are supplied to the electronic control unit 97, respectively.

Next, the shift control procedure executed by the electronic control unit 97 will be described with reference to the timing chart of FIG. 1 and the flowcharts of FIGS. 4 to 7.

First, in step 401 of FIG. 4, the electronic control unit 97
If it is determined that the automatic transmission is in a state in which it should shift from the first speed to the second speed as shown in FIG. 8 based on the input throttle opening θt signal and vehicle speed signal, it outputs a shift command and outputs the shift control electromagnetic wave. The valves 87 and 88 are switched as described above (step 402), the duty ratio of the solenoid valve 98 is set to a predetermined value (for example, 40%), and a drive signal is output to the solenoid valve 98 (Susu 403, first). (See FIG. (A)). As a result, a relatively high hydraulic pressure (electrically commanded hydraulic pressure) corresponding to a duty ratio of 40% is sent to the kickdown servo 80, and the piston 94 begins to stroke toward the engagement side (left side in FIG. 3) (No. (See FIG. 1 (c)). Note that the hydraulic pressure supplied to the kick gown servo 80 is actually lower than the hydraulic pressure actually acting on the piston 94 even if the electric command hydraulic pressure is changed in steps because the hydraulic chamber volume of the kick down servo 80 changes. Become.

Next, the throttle opening θt of the engine 2 is detected and stored in a predetermined storage location of the electronic control unit 97 (memory).
Yes (steps 404, 405). Then, the electronic control unit 97 detects that the detected throttle opening θt is divided into zones A to D in which the throttle opening range is divided into four as shown in FIG. The zone is a low throttle opening area, and B and C are intermediate throttle opening areas) (step 40
6).

In step 406, the throttle opening θt is, for example, D
If it is determined that the current position belongs to the zone (low throttle opening range), the constants θ1 ′ and d in the D zone are determined in the next step 407.
1'is read from the memory, and the coefficient α described later is also read from the memory. Then, the duty ratio d1 is calculated from the following equation (1) using these constants and coefficients (step 408).

d1 = d1′−α (θt−θ1 ′) (1) Here, the duty ratio d1 is a value representative of the duty ratio that gives the shift start hydraulic pressure at the previous shift in which the throttle opening θt belongs to the D zone. means.

Next, the shift initial duty ratio d4 and the duty ratio subtraction value (oil pressure change rate) β are calculated and determined by the following equations (2) and (3) (steps 409 and 410).

d4 = (d1 + 3m) / 4 (2) β = {6.8 + 1.1 × (m-d1) / 2} Δt (3) Note that m is the minimum hydraulic pressure required for the piston 94 to start Slotalk. Δt is a first timer set time for setting a cycle for subtracting the subtraction value β from the duty ratio d4, and is set to, for example, 50 msec.

Next, the electronic control unit 97 uses the piston stroke sensor 101.
The piston stroke position k is detected based on the detection signal from (step 411), and the detected value k is the maximum stroke value k2.
It is determined whether or not it has become a large value across a slightly smaller predetermined value {k2- (90/8) × 0.8} (step 41).
2). While the determination result is negative (NO), the electronic control unit 97 repeatedly executes steps 411 and 412, during which the duty ratio is held at the predetermined value (40%) (see FIGS. 1 (a) and (1)). See c)).

If the determination result of step 412 is affirmative (YES), that is, the piston stroke position detection value k is shown in FIG.
At this point, when the value crosses the predetermined value {k2− (90/8) × 0.8} and becomes a large value, the process proceeds to step 501 in FIG. 5, and the electronic control unit 97 determines that the shift initial duty ratio determined in step 409 is set. At d4, a drive signal is output to the solenoid valve 89 (see FIG. 1 (a)). Next, in step 502, after the first timer (Δt = 50 msec) is set, the rotation speed Nt of the turbine 10 corresponding to the input shaft rotation speed and the rotation speed No of the transfer drive gear 60 corresponding to the output shaft rotation speed No. Are respectively detected (step 503) and the process proceeds to step 504. In step 504, it is determined whether or not the first speed out-of-sync defined by Nt ≦ No × 2.846 has been achieved. If the result of this determination is that the first-speed out-of-sync has not been achieved, in step 505, Waiting for the first timer to time up, and if the first timer times out, the previously calculated subtraction value β is subtracted from the duty ratio d4 to obtain a new duty ratio d4 (step 506). ). Then, returning to the step 501, the solenoid valve 98 with the new duty ratio d4 is set.
The drive signal is output to. Unless the determination result of step 504 is affirmative (YES), that is, unless the out-of-synchronization of the first speed is achieved, the above steps 501 to 506 are repeatedly executed, and the duty ratio d4 is a subtracted value at each predetermined timer time Δt. .beta. is subtracted, the hydraulic pressure sent to the kickdown servo 80 gradually rises, the drum pressing force of the kickdown brake 30 increases, and the transmission output shaft torque decreases (FIG. 1 (b)). , (D) and (e)).

As described above, the duty ratios are compared until the piston stroke position k reaches the predetermined value {k2− (90/8) × 0.8}, which is slightly smaller than the stroke position at which the engagement of the kick down brake 30 is started. Set a relatively large value (40%), stroke the piston 94 of the kickdown servo 80 with a large hydraulic pressure, and when the predetermined value {k2− (90/8) × 0.8} is reached, give the shift start hydraulic pressure at the previous shift. Initial shift duty ratio determined based on a value that represents the duty ratio
Since d4 is used and then the duty ratio is gradually reduced with this gear shift initial duty ratio d4 as the initial value, the period from the gear shift command to the gear shift start is short, and so-called braking feeling does not occur.

When it is determined in step 504 that the first speed out of synchronization has been achieved and the shift has started, the shift control by the feedback control according to the present invention is started.

First, in step 601 of FIG. 6, the second timer is set (the timer time is set to 0.1 sec, for example), and then the turbine corresponding to the throttle opening θt.
The target change rate ωs of the rotational speed of 10 is calculated (step
602). This target rate of change ωs is such that, as the rotation speed of the turbine 10 is shown by the alternate long and short dash line in FIG. 1 (f), engagement shock or excessive slippage of the kickdown brake 30 does not occur.
It is set to a value that decreases at the optimum rate of change. next,
The actual rotation speed change rate ωt of the turbine 10 is calculated from the previous detection value and the current detection value (step 603), and the deviation Δω (= ωs−ω) between the actual rotation speed change rate ωt and the target change rate ωs.
t) is calculated (step 604). Next, proceeding to step 605, after calculating the gain γ (= b · Δω, where b is a constant) for the deviation Δω, it is determined whether or not the second timer has timed out ( Step 60
6). If the second timer has not timed up yet, the process proceeds to step 607, the gain γ obtained in step 605 is multiplied by a predetermined coefficient (for example, 1/2), and the product value (γ
X1 / 2) is a new gain γ. Then, using the gain γ thus obtained, the duty ratio correction amount Δd
(= Γ · Δω) is calculated (step 608), the duty ratio correction amount Δd is added to the previous duty ratio d1, and this is set as the current duty ratio do (step 609). The duty ratio do is stored in the memory of the electronic control unit 97 for the next duty ratio calculation. Electronic control unit 97
Outputs a drive signal to the solenoid valve 98 at the duty ratio do obtained in step 609 (step 610). As described above, the absolute value of the actual rotation speed change rate ωt immediately after the start of the shift is often smaller than the target change rate ωs, and the duty ratio correction amount Δd is adjusted by using the gain γ corrected to a small value as described above.
By setting, a rapid change in the rotation speed of the turbine 10 can be avoided, and it can be changed smoothly as shown by the solid line in FIG. 1 (f).

Next, after detecting the actual rotation speed Nt of the turbine 10 and the rotation speed No of the transfer drive gear 60 respectively (step
611), it is determined whether or not the synchronization to the second speed defined by Nt ≦ No × 1.581 is achieved (step 612). As a result of this determination, when the second speed synchronization is not achieved, the process returns to step 603 and steps 603 to 612 are repeatedly executed,
The rotational speed of the turbine 10 gradually decreases while following the rotational speed change that changes at the target rate of change ωs, which is indicated by the one-dot chain line in FIG. 1 (f) (solid line in FIG. 1 (f)). When the second timer times out and the determination result of step 606 becomes affirmative (YES), step 607 is not executed, the gain γ obtained in step 607 is not corrected, and the duty ratio correction of step 608 is not performed. It is applied to the calculation of the quantity Δd. Thus, the hydraulic pressure supplied to the kick-down servo 80 is optimally controlled without sudden change at the start of gear shift, and thus gear shift without shift shock is achieved.

When the second speed synchronization is achieved as a result of the determination in step 612, the process proceeds to step 701 in FIG. 7 and the third timer is set (this third timer setting time is 0.1 sec, for example).
Is set to). This third timer is for continuously holding the duty ratio do immediately before the second speed is achieved and outputting a drive signal to the solenoid valve 98 at this duty ratio do. You can expect perfect synchronization. Now, when the setting of the third timer is completed, the routine proceeds to step 702, where the coefficient α to be applied at the next shift in the D zone is obtained from the duty ratio do and the throttle opening θo by the following equation (4) and stored. (Memory) is stored (steps 702 and 703).

α = (d1′−do) / (θo−θ1 ′) (4) The coefficient α is the duty ratio at the time when the second speed synchronization is achieved.
do is corrected by feedback control according to the use condition of the transmission, and is calculated from the corrected duty ratio do and throttle opening θo. Therefore, if this coefficient α is used, it is more appropriate when shifting in the D zone next time. It is possible to determine a proper duty ratio d1 and eventually a shift initial duty ratio d4.

Next, in step 704, it is determined whether or not the third timer has timed out. If the answer is no (NO), repeat step 70 until the timer times out.
4, the electronic control unit 97 waits for the solenoid valve with the duty ratio do set immediately before the time point when it is determined in step 612 that the second speed synchronization has been achieved.
Continues to output drive signal to 98. When the third timer times out, the electronic control unit 97 sets the duty ratio do to 0% (step 705) and outputs a drive signal to the solenoid valve 98 at the duty ratio, that is, deactivates the solenoid valve 98 (step 705). Step 70
6). At this time, the kickdown servo 80 is supplied with the maximum line pressure, which is 1
The shift from the second speed to the second speed is completed (step 707).

In the above-described embodiment, the throttle opening θt detected in step 404 of FIG. 4 is described as belonging to the D zone, but even if the detected throttle opening θt belongs to another zone, Since the same description can be made, the description of those cases will be omitted.

Further, in the above-described embodiment, the timer is set in step 601 of FIG. 6 and it is determined in step 606 that the timer has timed out, so that the gain γ is corrected over the period when a predetermined time elapses from the shift start. However, the present invention is not limited to this.
It may be set in a period in which the rotating elements such as rotate a predetermined number of times.

Further, instead of correcting the gain γ for a predetermined period, the deviation Δω may be compared with a predetermined value, and when the deviation Δω is larger than the predetermined value, the gain γ may be corrected to a small value.

Furthermore, in the above-mentioned embodiment, the shift control for shifting from the first speed to the second speed has been described as an example, but the present invention is not limited to this, and
Of course, it may be applied to the shift control from the third speed to the third speed.

(Effects of the Invention) As described in detail above, according to the shift control method for an automatic transmission for a vehicle of the present invention, the deviation value between the actual rotation speed change rate of the rotating element and the preset target change rate is predetermined. When it is larger than the value, the correction gain is changed to a smaller value, and the drive signal supplied to the electric / hydraulic converter is corrected with the changed correction gain, so that the shift shock in the feedback control at the start of the shift can be prevented. It has an excellent effect that it can be achieved.

[Brief description of drawings]

FIG. 1 shows each time of duty ratio, kickdown servo hydraulic pressure, piston stroke position k, drum pressing force, transmission output shaft torque, and input shaft rotation speed during shift control by the method of the present invention and the conventional method (broken line). Fig. 2 is a graph showing changes, Fig. 2 is a schematic configuration diagram showing an example of an automatic transmission for a vehicle for carrying out the method of the present invention, Fig. 3 is a circuit diagram showing a part of its hydraulic control circuit, and Figs. The figure shows the electronic control unit 97 in FIG.
A flowchart showing a shift control procedure executed by
FIG. 8 is a graph showing a shift range between the first speed and the second speed. 2 ... Engine, 10 ... Turbine, 20 ... Input shaft, 30 ...
… Kick down brake, 50 …… Output shaft, 80 …… Kick down servo, 94 …… Piston, 97 …… Electronic control unit,
98 …… Solenoid valve, 101 …… Piston stroke sensor, 200
...... Throttle sensor, 201 …… Rotation speed sensor.

Claims (3)

[Claims] 1. An input shaft into which rotational power of an engine is input, an output shaft that outputs rotational power to drive wheels, and a plurality of gears that shift the rotation of the input shaft to transmit the rotational power to the output shaft. A rotating element, and a friction engagement element that operates by hydraulic pressure and that switches a gear ratio between the input shaft and the output shaft by selecting a predetermined rotating element from among the plurality of rotating elements according to an engine operating state, The actual rotation speed detected by detecting the actual rotation speed change rate of the rotating element during gear shifting of the automatic transmission for a vehicle, which comprises an electric-hydraulic converter for electrically controlling the hydraulic pressure supplied to the friction engagement element. In a shift control method of supplying a drive signal corrected by a correction gain according to a deviation between a speed change rate and a preset target change rate to the electric / hydraulic converter, thereby feedback controlling the hydraulic pressure to the rotary element. , The above When the difference is greater than a predetermined value, the change of the corrected gain to a small value, the shift control method of a vehicular automatic transmission, characterized by modifying said drive signals in a modified gain to the change. 2. An input shaft for inputting rotational power of an engine, an output shaft for outputting rotational power to drive wheels, and a plurality of gears for shifting rotation of the input shaft to transmit the rotational power to the output shaft. A rotating element, and a friction engagement element that operates by hydraulic pressure and that switches a gear ratio between the input shaft and the output shaft by selecting a predetermined rotating element from among the plurality of rotating elements according to an engine operating state, The actual rotation speed detected by detecting the actual rotation speed change rate of the rotating element during gear shifting of the automatic transmission for a vehicle, which comprises an electric-hydraulic converter for electrically controlling the hydraulic pressure supplied to the friction engagement element. In a shift control method of supplying a drive signal corrected by a correction gain according to a deviation between a speed change rate and a preset target change rate to the electric / hydraulic converter, thereby feedback controlling the hydraulic pressure to the rotary element. , The above For a predetermined time period from the start of the fed back control, to change the modified gain to a small value,
A shift control method for an automatic transmission for a vehicle, wherein the drive signal is corrected with the changed correction gain. 3. The shift control method for an automatic transmission for a vehicle according to claim 2, wherein the drive signal is corrected with a correction gain according to the deviation after the lapse of the predetermined period.