JPH07117141B2 - Shift control device for automatic transmission - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission adapted to be shifted by engaging or disengaging a plurality of hydraulically actuated frictional engagement elements, thereby reducing shift shock. The present invention relates to a shift control device.

2. Description of the Related Art Generally, in a vehicle equipped with an automatic transmission, when a vehicle is stopped in a driving range position, a predetermined friction engagement element is engaged in preparation for start-up so that power can be transmitted. Creep phenomenon occurs due to dragging of the joint (torque converter), which causes various problems. Therefore, the one in which the frictional engagement element is released to prevent the creep phenomenon while the vehicle is stopped is disclosed in JP-A-59-12.
As disclosed in Japanese Patent No. 8552, in this case, the loss stroke when the frictional engagement element is fastened at the time of starting becomes a problem, so the loss stroke amount to prepare for starting is compensated by hydraulic pressure supply. Is proposed. Therefore,
When compensating for the loss stroke in this way, it is necessary to precisely control the supply fluid pressure in order to prevent shock when fastening the friction engagement element.

As means for controlling the liquid pressure, for example, Japanese Patent Laid-Open No. 60-2202
As disclosed in Japanese Patent Publication No. 47, the condition value such as the number of revolutions input from the fluid coupling to the automatic transmission is detected, and the friction engagement element is controlled by controlling the hydraulic pressure so that the number of revolutions becomes a target value. The fastening timing, that is, the slip amount is controlled to reduce the fastening shock.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the hydraulic control device disclosed in Japanese Patent Laid-Open No. 60-220247, as shown in FIG. Is the target speed This target speed based on Both speeds are controlled because it is controlled to approach The greater the difference between The amount of hunting increases, and stable hydraulic pressure control cannot be obtained due to variations in the liquid temperature and the accuracy among the devices, and a large torque fluctuation occurs.

Therefore, in the present invention, when the condition value is largely deviated from the target value, a new target value is set without forcing control based on the original target value, and based on this new target value, An object of the present invention is to provide a shift control device for an automatic transmission, in which a hunting amount is reduced by controlling a condition value to perform precise control of an engagement timing.

In order to achieve the above object, the shift control device for an automatic transmission according to the present invention has a plurality of hydraulically operated friction engagement elements (a) as shown in FIG. ), The input rotation is appropriately changed in speed to be output, and the condition value for determining the engagement timing of the friction engagement element (a) is brought closer to a preset target value. In an automatic transmission adapted to control the hydraulic pressure supplied to the combination element (a), means (b) for determining whether an error between the condition value and the target value is within a predetermined value. When the error exceeds a predetermined value, means (c) for setting a new target value on the basis of the condition value which is out of the predetermined value is provided.

With the above configuration, the shift control device for an automatic transmission according to the present invention sets a new target value by the target value setting means (c) when the determination means (b) determines that the condition value is out of the predetermined value. After setting the condition value as a reference and setting the new target value, the condition value is controlled based on the new target value. Therefore, it becomes possible to bring the new target value and the condition value closer to each other, the feed back amount of the condition value is reduced, and the control hunting amount of the condition value is greatly reduced. Therefore, the engagement timing of the frictional engagement element (a) controlled by the condition value is also controlled so as to reduce the torque fluctuation.

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

That is, FIG. 2 is a schematic configuration diagram of a main part of a shift control device 1 for an automatic transmission showing an embodiment of the present invention, in which 2 is an engine, 3 is a torque converter as a fluid coupling, and 4 is a gear train of the automatic transmission. Indicates. The torque converter 3 is a pump impeller connected to the crankshaft 2a of the engine 2.
3a and a turbine runner 3b connected to the input shaft 4A of the gear train 4, the pump impeller 3a and the turbine runner 3b are adapted to transmit power via a torque transmission medium (oil or the like).

On the other hand, as the gear train 4, for example, as shown in FIG. 3, a sun gear S ₁ , a planetary gear P ₁ , a carrier.
A first planetary gear train 4a composed of C ₁ and a ring gear R ₁ and a second planetary gear train 4b composed of a sun gear S ₂ , a planetary gear P ₂ , a carrier C ₂ and a link gear R ₂ are also provided and shown in the drawing. Clutches F ₁ , F ₂ , F ₃ , F ₄ as friction engagement elements
And the brake F ₅ is disposed, and summer as further has two one-way class Tutsi F _6, F ₇ is provided. In addition, 4B is an output shaft. Then, at each shift speed (first, second, third, fourth speed and reverse), as shown in the following table, the friction engagement element F ₁ ,
_{F 2, F 3, F 4} , F 5 and one way class Tutsi F _6, F ₇ are summer as engagement and disengagement.

By the way, the friction engagement element 5 shown in FIG. 2 is exemplified by a clutch type, and the piston 5b makes a stroke by supplying hydraulic fluid such as lubricating oil into the cylinder 5a. The drive plate 5c and the driven plate 5d are brought into pressure contact with each other by the pressing force, and are fastened. Further, the frictional engagement element 5 is released by removing the hydraulic fluid from the cylinder 5a.

A pressure reducing supply circuit 6 for supplying hydraulic fluid from a hydraulic pump P is connected to the cylinder 5a of the friction engagement element 5, and a line pressure is introduced into the hydraulic pressure supply circuit 6 via a manual valve 9. It is becoming like this. An actuator for controlling the amount of hydraulic fluid supplied to the friction engagement element 5, for example, an electromagnetic proportional solenoid valve 7 is provided in the hydraulic pressure supply circuit 6, and the electromagnetic proportional solenoid valve 7 is connected from a micro computer 8. It is designed to be driven by the drive signal.

The solenoid proportional solenoid valve 7 has a spool 7b and a solenoid 7c in a valve body 7a as shown in FIG.
The driven plunger 7d is housed, and the spool 7b is actuated against the biasing force of the spring 7e by driving the plunger 7d. The valve body 7a is formed with an inlet port 7f, an outlet port 7g and a drain port 7h. The inlet port 7f is connected to the line pressure supply side of the hydraulic pressure supply circuit 6, and the outlet port 7g is hydraulic pressure. It is adapted to be connected to the friction engagement element 5 side of the supply circuit 6. And the spool shown
In the neutral position of 7b, the outlet port 7g is blocked from the inlet port 7f and the drain port 7h, and when the spool 7b is moved to the left in the figure from this neutral position, the inlet port 7f and the outlet port 7h are removed. 7g communicates with each other to hydraulically supply the frictional engagement element 5 and fasten it, while the spool port 7b moves rightward in the drawing from the neutral position, the outlet port 7g communicates with the drain port 7h. The frictional engagement element 5 is released.

On the other hand, the microcomputer 8 is provided with a signal (ω _e ) from the engine rotation sensor 10 for detecting the rotation of the crankshaft 2a and an input shaft rotation sensor 11 for detecting the rotation of the input shaft 4a.
(Ω _t ) from the output shaft rotation sensor 12 for detecting the rotation of the output shaft 4B and the signal (ω _o ) from the output shaft rotation sensor 12 are input. Then, based on these signals (ω _e , ω _t , ω _o ), the microcomputer 8 calculates a drive signal to be output to the solenoid proportional solenoid valve 7.

With the above-described configuration, in the hydraulic control device 1 for the automatic transmission of this embodiment, the power of the engine 2 is input from the input shaft 4a to the gear train 4 via the torque converter 3, while the hydraulic pump driven by the engine 2 is used. The hydraulic fluid discharged from P is regulated as a line pressure by a pressure regulating valve (not shown) and then supplied to the manual valve 9, and is supplied from each port corresponding to the range position of the manual valve 9 to the hydraulic pressure supply circuit 6. It is supplied to the friction engagement element 5 via the electromagnetic proportional solenoid valve 7 and the gear shift is performed according to the above table.

The electromagnetic proportional solenoid valve 7 is provided with a friction engagement element 5 according to a drive signal output from a microcomputer 8.
The hydraulic fluid pressure to be supplied to is determined, and the engagement timing of the friction engagement element 5 is designed by this hydraulic fluid pressure. The processing for controlling the drive signal input to the solenoid proportional solenoid valve 7 is performed along the flow chart shown in FIGS. 5 and 6. This flow chart is, for example, 5m at regular intervals
An example will be described in the case where it is executed every sec and the shift-up is performed from the second speed to the third speed.

That is, in this flow chart, when the ignition switch is initialized by turning on the ignition switch, step 100 first determines a shift. In other words, this shift determination is made by a program (not shown) based on driving conditions such as vehicle speed and throttle opening, and it is determined whether or not a shift is to be performed using a pre-stored shift map. If the shift is started (YES), the step is determined. If not (NO), that is, if gear shifting is not required or gear shifting is in progress, the routine proceeds to step 102. In step 101, the gear ratio (GA) after the gear shift is read from the gear shift map, the gear ratio is stored in a memory, and in step 103, the engine speed signal (ω
_e ), the input shaft rotational speed signal (ω _t ) and the output shaft rotational speed signal (ω _o ) are read and stored in the memory. Next, in step 104, ω _e read in step 103,
The speed ratio is obtained from ω _t , and the torque ratio and the input torque capacity coefficient are tabled up from this speed ratio to obtain the input shaft.
The torque (T _t ) of 4 A is calculated, and in step 105, the gear ratio (G
B) and the gear ratio (GA) after shifting stored in step 101, and the input shaft torque (T) calculated in step 104.
Target input shaft rotation change according to _t ) To calculate. At the next step 106, the output shaft 4B rotation speed (ω _OB ) immediately before the gear shift, that is, when the gear shift command is issued, is read. At step 107, ω _OB , Calculate the target shift time τ from GB and GA.

Then, in step 108, the rotational speed change ( _t ) of the input shaft 4A is obtained from ω _t , and the target rotational change of the input shaft 4A is obtained. Is determined by the table backup, and the next step 109
so The hydraulic fluid pressure value (P) is calculated as follows. And step 11
At 0, a drive signal corresponding to this hydraulic pressure value (P) is output to the solenoid proportional solenoid valve 7 to cause the engagement operation of the friction engagement element 5, and at step 111, the flag (FLG) is set to 1
The shift start is set as, and this control is once ended.

On the other hand, if it is determined in step 100 that the gear shift operation is other than the gear shift start and the process proceeds to step 102, it is determined whether the gear shift operation is in progress or the gear shift is not required. That is, in this step 102, the flag is zero (FLG = 0.
Is the end of gear change) and FLG = 0 (Y
In (ES), no gear change is required, so supply of hydraulic fluid is not required, and this control is temporarily terminated. Next, if FLG ≠ 0 (NO) in step 102, it means that the gear is being changed.
At 112, shift control is performed to precisely control the hydraulic pressure.

That is, the control in step 112 is a control for substantially determining the engagement timing of the friction engagement element 5, and is the most important part in the series of shift control. FIG. 6 shows the step 11
2 is a flow chart for performing gear shift control. In step 120, an engine speed signal (ω _e ) is received in response to a determination signal in step 102 in FIG.
Input shaft speed signal (ω _t ) and output shaft speed signal (ω
_o ) is read from the memory and the next step 121 is The rotational speed ratio (g) between the input and output shafts is obtained from After that, in step 122, it is judged whether or not the inertia phase after the gear shift in the transmission is actually started. That is,
In this control, as shown in FIG. 7, FLG = 0 was set as the shift end (or before the shift) and FLG = 1 was set as the shift start (or after the shift command). However, inertia phasing was further detected, and this inertia was detected. FLG = 3 for Yahoo Aids. For FLG = 2, the gear train momentarily slips immediately before the actual shift,
It represents a torque phase in which the output torque sharply drops, but it is not particularly required in the control of this embodiment. Therefore, in step 122, it is determined whether FLG = 1 and FLG = 1.
If (YES), it is judged that the inertia phasing has not yet been reached, and the program proceeds to step 123. On the other hand, if FLG ≠ 1 (NO), the remaining FLG = 3 is judged to be the inertia phasing and the procedure proceeds to step 124. move on. In this step 124, the elapsed time (t) after entering the inertia phase is integrated and measured for each predetermined time (Δt) of the flow processing, and in step 125, this measured time (t) is measured. It is determined whether the shift time (τ) calculated in 107 is exceeded. That is,
If t ≧ τ (YES), it means that the gear shifting is completed, the maximum hydraulic pressure is set in step 126, this drive signal is output to the electromagnetic proportional solenoid valve 7 in step 127, and FLG is output in step 128. Is zero, and step 129
Then, the gear ratio (GA) after shifting is set as the gear ratio (GB) before shifting, and the control is temporarily terminated.

If t <τ in step 125 (NO), it means that the shift is currently in the process of inertia phase.
At 130, the target input / output shaft rotational speed ratio () is calculated as a function of t, and thereafter, the current rotational speed ratio (g) is calculated based on this target rotational speed ratio () by steps 134 to 142. The shift control is performed by adjusting.

By the way, when it is judged that FLG = 1 (YES) at the step 122 and the program proceeds to step 123, at this step 123, ω
_While calculating the input shaft 4A torque (T _t ) from _e and ω _t ,
In step 131, the target input shaft speed change is calculated from T _t and ω _o. And the target shift time (τ) is calculated. Next, at step 132, it is judged if the change ( _t ) in the input shaft rotation speed is negative. That is, as is clear from the characteristics of the input shaft speed shown in FIG. 7, when the substantial shift stage, that is, the inertia phase, is entered, the input shaft speed is reduced, so that _t is negative ( _t <0. In the case of () (YES), it is determined that the product has entered the inertia fare, and at step 133, "3"
Flag is set and the routine proceeds to step 130.

By the way, in the step 130, the input / output shaft rotational speed ratio () as a target value is obtained, and the actual input / output rotational speed ratio (g) is controlled along the target rotational speed ratio ().
The following steps 134 to 142 are particularly the most important control parts in the shift control of this embodiment. That is, in step 134, the absolute value difference (Δg) between the target rotational speed ratio () and the actual rotational speed ratio (g) is obtained, and in the next step 135, the absolute value difference (Δg) is set in advance. Control value (ΔgLMT)
Compare with. And in the case of ΔgΔgLMT (YES),
In other words, when the actual speed ratio (g) matches or is close to the target speed ratio (), the routine proceeds to step 136, while when Δg> ΔgLMT (NO), that is, the actual speed ratio () is changed from the target speed ratio (). If the numerical ratio (g) is greatly deviated, the process proceeds to step 137.

When the process proceeds from step 135 to step 137, the target input / output shaft rotational speed ratio () is newly set in step 140 to step 140. That is, the step
In 137, the input shaft speed change ( _t ) at the time when it is judged that Δg> ΔgLMT is set as the initial value ( _to ) of the target input shaft speed change, and in step 138 the new initial value is set. Then, the target shift time (τ) is calculated from the output shaft speed (ω _o ), the gear ratio (GA) after shifting, and the actual gear ratio (input / output shaft speed ratio) (g). Next, in step 139, the initial value ( ₍₀₎ ) of the target input / output shaft rotational speed ratio is set as the actual input / output shaft rotational speed ratio (g), and in step 140 the count time (t) is set. Set to zero.

That is, in the series of control from step 137 to step 140, as shown in FIG. 8, the initial target input drawn by the solid line in FIG. If the actual input / output shaft speed ratio (g) indicated by the broken line greatly deviates from the output shaft speed ratio () characteristic,
A new target input / output shaft rotation speed ratio () is drawn from the actual measurement point (X) of the rotation speed ratio as shown by a two-dot chain line.

Then, from step 140, at step 135, Δg
Similar to the case where it is determined that ≦ ΔgLMT, the process proceeds to step 136,
Target input / output shaft speed ratio () (This target value ()
Is a new target value when passing through steps 137-140) and the actual input / output speed ratio (g). Is judged. That is, when it is determined in step 136 that = g, the process proceeds to step 141 without correction of the actual input / output shaft speed ratio (g), and in step 141, the input / output shaft speed ratio (g) is set. Is calculated, and in step 142, a drive signal corresponding to this hydraulic pressure value is output to the solenoid proportional solenoid valve 7 to end the control once. On the other hand, if it is determined that the value is> g in the step 136, the correction for reducing the hydraulic fluid pressure (P) is made via the step 143, that is, the correction for reducing the engaging force of the frictional engagement element 5 is performed. Continue to 142. If it is determined in step 136 that <g, a correction for increasing the hydraulic fluid pressure (P), that is, a correction for increasing the engaging force of the frictional engagement element 5 is performed via step 144, and the step is performed.
Continue to 142.

If the input shaft rotational speed change ( _t ) is zero or positive ( _t ≥ 0) in step 132 (NO), it is determined that the inertia phase is not included, and in this case, it is very precise. Since the hydraulic pressure control is not required, the flow goes to step 142 to output the hydraulic pressure value (P) signal calculated in step 109.

Therefore, in this embodiment, as described above, the input / output rotation ratio (g) as the condition value is changed from the input shaft rotation speed ratio () as the target value by the control in steps 134, 135 and 137 to 140. In the case of a large deviation, a new target value is drawn from the measurement point (X) of the input / output speed ratio (g) in the case of the large deviation. It is possible to eliminate an error from the output rotation speed ratio () and significantly reduce the hunting amount in the subsequent feed back control. Therefore, the engagement pressure of the friction engagement element 5 controlled by the drive signal from the micro computer 8 via the electromagnetic proportional solenoid valve 7 can be made stable, and accordingly, the torque in the inertia phase can be maintained. By suppressing the variation as shown by the chain double-dashed line in FIG. 8 (A), the engagement lock of the friction engagement element 5, that is, the gear shift lock can be greatly reduced.

FIG. 9 is a flow chart showing another control example of the present invention.
The same processing contents as those in the flow chart of FIG. 6 are designated by the same step numbers, and a duplicate description will be omitted.

That is, in this control example, the control value of FIG. 6 sets the detected value and the target value by the input / output shaft rotation speed ratio (g,), and the absolute value difference between these two (g,) is within the predetermined value. Whether the frictional engagement element 5 calculated by the both rotation speed ratio (g,) is shown in the control example of FIG. The change amount (f) of the hydraulic fluid pressure (P) is used to determine whether to set a new target value. That is, in this embodiment, the sixth
In the flow of newly setting the target value during control in the figure, steps up to step 130 are made common, and the processing up to step 142 thereafter becomes the new control content.

That is, the new control contents are changed from step 200 to step 2
The step 200 calculates the change amount (f) of the hydraulic fluid pressure (P) calculated from the target input / output shaft speed ratio () and the actual input / output shaft speed ratio (g). In the next step 201, it is judged whether or not the absolute value of the change amount (f) is within a preset limit value (f _LMT ).
Then, the absolute value is within the limit value (| f (, g) | ≦ f _LMT ).
If YES (YES), the routine proceeds to step 202, where the hydraulic fluid pressure (P) corrected in accordance with the hydraulic pressure change amount is calculated.

On the other hand, in step 201, outside the limit value (| f (, g) |> f
_LNO ), that is, if the actual input / output shaft speed ratio (g) deviates significantly from the target input / output shaft speed ratio (), the process proceeds to step 203. From step 203 to step 206, the sixth
The same processing as step 140 is performed from step 137 to step 207. In this step 207, when the deviation from the limit value (f _LMT ) is _reached , the first measured hydraulic pressure change amount (f) is set to zero, and then the process proceeds to step 202,
In the next step 142, a drive signal to the solenoid proportional solenoid valve 7 is output.

Therefore, even in this case, if the hydraulic pressure change amount (f) exceeds the predetermined value (limit value), a new target input / output shaft rotation speed ratio () is set again. The hunting amount by the feed back control of the input / output shaft rotation speed ratio (g) can be reduced to reduce the gear shift shock.

In the above-described embodiment, the input / output shaft rotation speed ratio (g,) is used as the condition value and the target value, but the fluid pressure of the friction engagement element 5 is not limited to this. The condition value and the target value are set according to the controllable conditions, for example, the rotation change of the input shaft 4A, the torque change of the input shaft 4A, the engine speed change, and the hydraulic pressure change, thereby controlling the gear shift. It is also possible to apply the present invention to such a thing.

As described above, in the shift control device for an automatic transmission according to the present invention, between the condition value for determining the engagement timing of the friction engagement element and the target value for controlling this condition value. If the error is significantly deviated from the predetermined value and is out of the predetermined value, a new target value is set again based on the condition value that is out of the predetermined value, and the condition value is controlled based on the new target value. Therefore, the hunting amount when the condition value is feedback-controlled can be significantly reduced. Therefore, by reducing the hunting amount of the condition value in this way, the friction engagement elements can be smoothly engaged, and the occurrence of gear shift shock can be suppressed, thereby significantly improving the riding comfort of the vehicle. It has an excellent effect that it can be achieved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the concept of a shift control device for an automatic transmission according to the present invention, FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention, and third is used for the automatic transmission according to the present invention. FIG. 4 is a schematic configuration diagram showing an embodiment of a gear train to be used, FIG. 4 is a cross-sectional view of an actuator used in the embodiment of the present invention, and FIG. 5 is an embodiment of a program processing for carrying out the shift control of the present invention. 6 is a flow chart showing a subroutine for processing the shift control of the present invention, and FIG. 7 is a time chart showing the characteristics of each condition at the time of upshift in the present invention, FIG. 8 (A). , (B) are characteristic diagrams of the output shaft torque and the input / output shaft speed ratio obtained by the present invention, FIG. 9 is a flow chart showing another process for controlling the present invention, and FIG. 10 is a conventional control. It is a characteristic view which shows an example. 1 ... Fluid pressure control device, 2 ... Engine, 3 ... Fluid coupling, 4 ...
Gear train, 5 ... Friction engagement element, 7 ... Electromagnetic proportional solenoid valve (actuator), 8 ... Microcomputer.

Claims (1)

[Claims] Claims: 1. By engaging or releasing a plurality of hydraulically-actuated friction engagement elements, the input rotation is appropriately shifted and output, and a condition value for determining the engagement timing of the friction engagement elements is set, In an automatic transmission in which the hydraulic pressure supplied to the friction engagement element is controlled so as to approach a preset target value, is an error between the condition value and the target value within a predetermined value? An automatic transmission characterized by: a means for determining whether or not the error exceeds a predetermined value, and a means for setting a new target value on the basis of a condition value outside the predetermined value, when the error exceeds the predetermined value. Shift control device.