JPH0231069A - Line pressure control device for automatic speed change gear - Google Patents

Abstract

PURPOSE:To prevent the occurrence of erroneous learning by a method wherein by means of a signal based on which it is indicated whether speed change is effected in a given mode from a speed change mode signal output means, a line pressure control under speed change based on an inertia phase time of a line pressure control means is specified. CONSTITUTION:A speed change gear mechanism selects a given speed change step in a way that various friction elements are selectively actuated by means of a line pressure. During the speed change, an inertia phase time measuring means measures a time in which a gear ratio is changed from a signal from an output rotation sensor, and a line pressure is controlled by a line pressure regulating means so that the gear ratio is adjusted to a target value. Meanwhile, a speed change mode signal output means outputs a signal by means of which it is indicated whether a speed change in which an inertia phase time is measured is a speed change in a given mode. Based on the signal, a control propriety discriminating means regulates control of learning based on the inertial phase time of the line pressure regulating means. This constitution prevents the occurrence of erroneous learning due to a difference in a car speed during speed change and enables control of a line pressure during speed change to a normally proper value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a line pressure control device for an automatic transmission, and more particularly to a device for appropriately controlling line pressure during gear shifting.

(Prior art) Automatic transmissions selectively hydraulically operate various friction elements (clutches, brakes, etc.) of a transmission gear mechanism using line pressure to select a predetermined gear, and change the friction elements to be operated. Shift to the next gear.

Therefore, if the line pressure is too high, the transient engagement capacity of the friction element becomes too large, causing a large shift shock. If the line pressure is too low, the transient engagement capacity of the friction element becomes too small, causing the friction element to slip. This leads to a decrease in service life. Therefore, it is necessary to properly control the line pressure.
As described in (A261CO7), the line pressure was controlled by determining the driving duty of the line pressure control solenoid based on the engine throttle opening from different table data during shifting and non-shifting.

However, in such conventional line pressure control devices, when there are product variations in the line pressure control solenoid or changes in characteristics over time, or when there are product variations in the friction elements or when the friction material changes over time. In the former case, the line pressure deviates from the appropriate value even with the same solenoid drive duty, and in the latter case, even if the line pressure is controlled as desired, it is not the appropriate value for the friction element. However, in any case, excessive or insufficient line pressure will inevitably cause a large shift shock and shorten the life of the friction elements.

By the way, for example, as shown in FIG.
Looking at the case of upshifting from 1st to 2nd speed by turning the shift solenoid from ON to OFF, if the line pressure is low, the 2nd speed selection pressure, which uses this as the source pressure, increases as shown by the solid line. The gear ratio expressed by the input/output rotational speed ratio NT/No (A: input rotational speed, No.: output rotational speed) of the transmission gear mechanism is the first.
The speed equivalent value changes to the second speed equivalent value as shown by the solid line, and the transmission output torque changes as shown by the solid line, whereas when the line pressure is high, the operating waveform becomes as shown by the dotted line.

Therefore, from the time during which the gear ratio Ny/No is changing, that is, the inertia phase time T, it can be determined whether the line pressure is at an appropriate value taking into account the above-mentioned variations and changes over time.

From this point of view, the present applicant previously applied for patent application No. 62-32745.
In No. 2, an input rotation sensor and an output rotation sensor respectively detect the input rotation speed and output rotation speed of the transmission gear mechanism of the automatic transmission mentioned above, and based on the signals from those sensors, the inertia phase time is determined. The measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and the line pressure adjusting means adjusts the line pressure during the shifting so that the inertia phase time reaches the target value. We have proposed a line pressure control device that controls line pressure, and with this device, line pressure control can be constantly performed in accordance with the actual situation of automatic transmissions, and the occurrence of large shift shocks and rifts due to excess or deficiency in line pressure can be avoided. It is possible to avoid reduction in the life of the friction elements.

(Problems to be Solved by the Invention) As the inventors of the present invention conducted further research on the above-mentioned device, they discovered the following points to be improved.

That is, the transient engagement capacity of the friction element of the automatic transmission mounted on a vehicle changes depending on the vehicle speed even if the engine throttle opening degree of the vehicle is constant. For example, when shifting with the power on while keeping the throttle open, a large engagement capacity is required when the vehicle speed is low, but a small engagement force is sufficient when the vehicle speed is high. On the other hand, when shifting with the power off while the throttle opening is kept at the minimum, a small engagement capacity is sufficient when the vehicle speed is low, but it is necessary to increase the engagement capacity to some extent when the vehicle speed is high.

Automatic transmissions have multiple types of shift patterns, such as economy patterns that shift at a relatively low vehicle speed at each throttle opening to keep the engine speed low and improve fuel efficiency, and Some automatic transmissions selectively use a power pattern that shifts at the vehicle speed to keep the engine speed high and improve responsiveness. The speed of the vehicle during shifting varies depending on the speed.

In addition, in an automobile transmission, it is usually possible to select manual gear shifting by manually operating the select lever, and in this case, gear shifting is performed at the same throttle opening at a different vehicle speed than in the case of automatic gear shifting based on the shift pattern as described above. There is.

However, the conventional line pressure control device described above does not depend on the vehicle speed, but only on the type of shift and the throttle opening.
A target value for the inertia phase time is set to optimize the line pressure during gear shifting. Therefore, when the above conventional device is applied to an automatic transmission with multiple types of shift patterns as described above, By comparing the inertia phase time target value suitable for the pattern with the measured value of the inertia phase time during shifting in the power pattern, learning control is performed to make the line pressure during shifting higher than necessary, and When you shift manually,
The problem with the shifting pattern, shifting method, and other shifting aspects, such as learning control being performed even if the vehicle speed at the time of the gear shifting is other than the vehicle speed that is compatible with the inertia phase time target value at the throttle opening at that time. Since learning control is performed regardless of the situation, there is a risk that the occurrence of shift shock may not be sufficiently prevented.

The present invention provides a device that advantageously solves this problem.

(Means for Solving the Problems) As shown in FIG. 1, the line pressure control device for an automatic transmission of the present invention selectively hydraulically operates various friction elements of a transmission gear mechanism using line pressure to achieve a predetermined gear position. An input rotation sensor and an output rotation sensor detect the input rotation speed and the output rotation speed of the transmission gear mechanism of an automatic transmission in which the transmission gear mechanism is configured to select and shift to another gear stage by changing the operating friction element. Based on the signals from these sensors, the inertia phase time measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and the line pressure adjusting means In a line pressure control device that controls the line pressure during the shifting so that the inertia phase time becomes a target value, a signal is output indicating whether or not the shifting for which the inertia phase time is measured is a shifting in a predetermined manner. A shift mode signal output means; and a control propriety determination means for specifying control of the line pressure of the line pressure adjustment means during a shift based on the inertia phase time based on the signal from the shift mode signal output means. It is characterized by becoming.

(Function) In such a device, the transmission gear mechanism selectively hydraulically operates various friction elements using line pressure to select a predetermined gear position, and outputs the supplied power by increasing or decelerating it at this gear position. The transmission gear mechanism is then shifted to another gear stage by changing the hydraulically operated friction element.

During this time, the input rotation sensor and the output rotation sensor are respectively detecting the input rotation speed and output rotation speed of the speed change gear mechanism. The inertia phase time measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds of the speed change gear mechanism is changing, that is, the inertia phase time during the speed change, based on the signals from these two sensors. Then, the line pressure adjusting means controls the line pressure so that the inertia phase time reaches the target value.

On the other hand, the shift mode signal output means outputs a signal indicating whether or not the shift measured by the inertia phase time is a shift in a predetermined mode, and the controllability determination means outputs a signal from the shift mode signal output means. Based on this, learning control based on the inertia phase time of the line pressure adjusting means is regulated.

Therefore, with this device, even if there are product variations in the line pressure control element or changes in characteristics over time, or even if there are product variations in the friction element or changes in the friction material over time, these It is possible to perform line pressure control that takes into account individual differences in automatic transmissions and changes over time, and it is possible to avoid large shift shocks and shortened lifespans of friction elements due to excessive or insufficient line pressure. Even if the machine performs automatic gear shifting or manual gear shifting by selectively using multiple types of shift patterns, only if the gear shifting mode is a predetermined one, i.e., depending on the vehicle speed at the time of the gear shift or the throttle opening at that time. Since learning control is performed only when the value is a predetermined value, erroneous learning due to differences in vehicle speed during gear shifting can be prevented, and line pressure control during gear shifting can always be properly controlled.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 2 shows a power train control system of an automobile incorporating an embodiment of the line pressure control device of the present invention, in which 1 is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, and 4 is a drive. It's a wheel.

The engine 1 includes an engine control computer 5, which detects a signal from an engine rotation sensor 6 that detects the engine rotation speed NE, a signal from a vehicle speed sensor 7 that detects the vehicle speed, and an engine throttle opening TH. A signal from the throttle sensor 8 that detects the engine intake air amount Q, a signal from the intake air amount sensor 9 that detects the engine intake air amount Q, etc. are manually generated.

The computer 5 determines the fuel injection pulse width T based on the input information and instructs the engine 1 to do so, and also supplies an ignition timing control signal (not shown) to the engine 1. The engine 1 is supplied with an amount of fuel according to the fuel injection pulse width T, and is operated by burning this fuel in time with the rotation of the engine.

The automatic transmission 2 also includes a torque converter 10 and a speed change gear mechanism 11 in tandem, and inputs engine power to an input shaft 12 via the torque converter 10.

The transmission input rotation to the shaft 12 is increased or decreased according to the selected gear position of the transmission gear mechanism 11, and reaches the output shaft 13. From this output shaft, the rotation passes through the differential gear 3 and reaches the driving wheels 4, so that the vehicle can be driven. can.

Here, the speed change gear mechanism 11 is connected from an input shaft 12 to an output shaft 13.
Various friction elements (not shown) such as clutches and brakes are built in to determine the transmission path (gear position) to the gear, and these various friction elements are selectively hydraulically actuated by line pressure PL to select a predetermined gear position. At the same time, shifting to other gears is performed by changing the friction elements that are operated.

For this speed change control, a speed change control computer 14 and a control valve 15 are provided here.

The computer 14 selectively turns on shift solenoids 15a and 15b for speed change control in the control valve 15.
L. Controls shift control by selectively supplying line pressure pt to various friction elements so that the corresponding gear stage is selected by the combination of ON and OFF of these shift solenoids. In addition, the shift control computer 14 duty-controls a line pressure control duty solenoid 16 in the control valve 15 using a driving duty D to control the line pressure P in the control valve 15.

(Increase in line pressure as duty D increases) shall be controlled as intended by the present invention. In order to control the speed change and line pressure, the computer 14 receives a signal from the vehicle speed sensor 7 and a signal from the throttle sensor 8, respectively, and also inputs a rotation sensor 17 that detects the rotation speed NA of the shaft 12.
and the rotational speed N of the shaft 13. A signal from the output rotation sensor 18 that detects the rotation is input.

In addition, the automatic transmission 2 here has an economy pattern in which the gear is shifted at a relatively low vehicle speed at each throttle opening TH to keep the engine speed low and improve fuel efficiency, and an economy pattern at each throttle opening Tl+. , shifts at a relatively high vehicle speed to maintain a high engine speed,
It is assumed that two types of shift patterns are selectively used: a power pattern and a power pattern that improve the response of the vehicle to the operation of the throttle pedal; therefore, here, the signal SP from the shift pattern selection switch 19 is also input to the computer 14. do.

Further, the computer 14 is configured so that the driver can control the automatic transmission 2.
A signal M3 from the inhibitor switch 20 indicating that manual gear shifting is to be performed by operating a select lever (not shown) is also input.

The computer 14 executes the control programs shown in FIGS. 3 to 5 to perform line pressure control and speed change control.

First, the line pressure control program shown in FIG. 3, which is repeatedly executed by regular interrupts, will be explained. In step 30, it is checked whether or not the gear is being changed by checking whether a flag FLAG 1, which will be described later, is set to 1. As a result, during non-shifting (FLAG 1 =
0), in step 31, the line pressure control solenoid drive duty D corresponding to the throttle opening TH is obtained from the non-shift duty table 1 written in the RAM and having the characteristics as shown by the solid line A in FIG. 6, for example. A table lookup is performed, and then in step 32, this drive duty D is output to the solenoid 16 to control the line pressure PL to a normal value for non-shifting.

On the other hand, as a result of the above check, the gear shift is in progress (FLAG 1 = 1
), in step 33, the gear, upshift,
This differs depending on the type of shift such as downshifting, and this is also RAM.
The line pressure control solenoid drive duty D corresponding to the throttle opening TH is looked up from the shift duty table 2 having characteristics as shown by the dotted line B in FIG. It is checked whether or not the shift is an upshift in which shift shock is particularly likely to occur due to excessive line pressure, and if the result is not an upshift, in this example device, the drive duty D is directly output to the solenoid 16 in step 32. do. On the other hand, in the case of an upshift, in step 35, RAM is stored for each type of shift using learning control described later.
For example, the line pressure control solenoid drive duty correction amount 7!1D corresponding to the throttle opening TH is looked up from the correction amount table as shown in FIG.
to control the line pressure PL to a value for shifting.

Next, to explain the shift control and line pressure control solenoid drive duty correction amount control shown in FIG.
Check whether 1 is 1, that is, whether the gear is being shifted,
If not shifting (FLAG 1 = O), step 41
Based on the selected shift pattern based on the signal S from the shift pattern selection switch 19, a required gear stage corresponding to the combination of vehicle speed (2) and throttle opening TH is determined.

Here, the shift pattern selection switch 19 can be selectively operated to "auto" or "power", and the shift control computer 14 receives a signal S from the switch 19.
, indicates that it has been operated in "auto" mode, the economy pattern is normally used, and the throttle pedal depression speed is equal to or higher than a set value determined according to the throttle opening TH and vehicle speed V. When the throttle opening degree TH returns to a certain level or less and a certain period of time elapses, the economy pattern is changed to the power pattern, and only the power pattern is used when the signal S2 indicates that the signal S2 has been operated to "power".

Incidentally, in this step 41, the inhibitor switch 2 is also
It is also checked whether manual shifting is to be performed based on the signal from 0, and in the case of manual shifting, the requested gear is limited to a low gear (for example, first gear or second gear).

In the next step 42, it is checked whether or not the gear should be changed based on whether the requested gear is different from the currently selected gear. If the result is that the gear should be shifted, then in step 43, a message is displayed to indicate that the gear is being shifted. In addition to setting FLAG 1 = 1, the solenoids 15a and 15b are turned ON and OFF to execute the shift to the above-mentioned required gear position, and in the subsequent step 44, it is checked whether or not manual shifting is being performed. If you skip step 45 and go to step 46
On the other hand, if manual gear shifting is not in progress, that is, if automatic gear shifting is in progress in the economy pattern or power pattern, the process proceeds to step 45. Then, in step 45, it is checked whether or not the power pattern is in use, and if the power pattern is in use, in step 46, the FL
After setting AG 3 = 1, proceed to step 47, while
If the economy pattern is being used, step 46 is skipped and the process proceeds to step 47.

As a result, only when the speed change mode is an automatic shift in the economy pattern, the flag FL indicating the speed change mode is set.
Keep AG 3 at 0, otherwise FLAG 3
Set to 1.

Note that during the gear shift (FLAG 1
=1), steps 41 to 46 are skipped in the next control.

In step 47, timer T measures the shift time.

is incremented (stepped), and in the next step 48 it is checked whether or not it is in the inertia phase.

In this check, the gear ratio represented by the input/output rotation speed ratio NT/No of the transmission gear mechanism 11 is not changed from the gear ratio corresponding to the gear before shifting to the gear ratio corresponding to the gear after shifting. The period of change is determined to be in the inertia phase. And here, during the inertia phase, step 4
By incrementing the timer T2 at step 9 and skipping step 49 after the inertia phase, the timer T2 measures the inertia phase time.

In the next step 50, it is checked whether or not the inertia phase has ended (the end of the shift). If it has not ended, the program is terminated as is, and if it has ended, the flag FLAG 1 is set to correspond to the end of the shift in step 51. TeO
At the same time, a flag FLAG 2 is set to 1 for executing learning control for correcting the data in the correction amount table in the RAM shown in FIG.

After the shift is finished in this way, the control proceeds to step 52 via steps 40 to 42 while no shift is performed, but since FLAG2 = 1 as described above, step 53 is selected and the following learning is performed. By control, the previous data of the line pressure control solenoid drive duty correction amount ΔD shown in FIG. 7 is corrected and updated.

In this step 53, the learning control subprogram shown in FIG. 5 is executed.
Check whether G 3 = 1 or not, then F 8 G 3 = 1
If not, since the immediately previous shift was an automatic shift in an economy pattern, the process proceeds to step 61, where it is checked whether the immediately previous shift was an upshift shift. If it is not an upshift shift, the learning control is not performed as described above, and the process ends. If it is a - direction upshift shift, the timer T1, that is, the shift time, is checked in step 62 to see if it is greater than a predetermined value Ls. . Timer T for line pressure control solenoid drive duty D+ΔD% during gear shifting
The measurement time of I+ 'rZ is as shown in Figure 8, where the power pattern in power-on upshift is shown by a dotted line, and the economy pattern is shown by a solid line. When the line pressure is extremely small, such as α in the region showing At this point, the friction element is rapidly engaged due to a sudden increase in the selection pressure, resulting in off-shelf shifting as shown by the dotted line α in Figure 9, and the shift shock becomes extremely large (solid line β in Figure 9, The dashed line T indicates that the solenoid drive duty is the 8th.
(Operating waveforms at the values indicated by the same symbols in the figure). In order to prevent this off-shelf shifting, if it is determined in step 62 that T, ≧T's, then in step 63 the throttle opening TH at the time of gear shifting is determined from the correction amount table mentioned above corresponding to the type of gear shifting. The line pressure control solenoid drive duty correction amount ΔD corresponding to the line pressure control solenoid drive duty correction amount ΔD is looked up, and in the subsequent step 64, the correction amount ΔD is significantly increased by 2%, and the subsequent step 6
In step 5, the table data in RAl'l is rewritten to the correction amount ΔD so as to quickly escape from the T1≧'ris region.

T + < T Is? In the +Jj range, since there is no above concern, learning control of the correction amount ΔD is performed, and first, in step 66, a line pressure that is suitable for preventing shift shock and preventing reduction in the life of friction elements in shifting in an economy pattern is adjusted. Target value of inertia phase time (varies depending on the type of shift and throttle opening) T2. is looked up from the inertia phase time target value table in the RAM, and in step 67, the line pressure control solenoid drive duty correction amount corresponding to the throttle opening TH is determined from the correction amount table mentioned above corresponding to the type of shift. Look up ΔD, step 68
The inertia phase time T2 is compared with the target value TZS.

As a result of the comparison in step 68, T2 is TZ3.
When they match, the table data in the RAM for the correction amount ΔD is not changed and is used as it is for line pressure control during the next shift. However, when Tz>Tzs, the line pressure is too low and the life of the friction element is shortened due to slipping. Therefore, by executing steps 69 and 70, the table data in the RAM of the correction amount AD corresponding to the type of gear change is 0.
It is increased by 2% and used for line pressure control during the next gear shift. Therefore, during the next line pressure control, the line pressure control solenoid drive duty D + ΔD is increased by 0.2% from the previous time, and the line pressure can be increased by that amount, bringing the line pressure closer to the appropriate value and extending the life of the friction element. decline can be avoided. Conversely, when rz<TzsO, the line pressure is too high and a large shift shock occurs due to the excessive engagement capacity of the friction element. Therefore, by executing steps 71 and 70, the correction amount AD corresponding to the type of shift is stored in the RAM. The table data is reduced by 0.2% and used for line pressure control during the next gear shift. Therefore, the line pressure control solenoid drive duty D+, dD during the next line pressure control is 0.2% compared to the previous time.
As a result, the line pressure can be lowered, and the line pressure can be brought closer to an appropriate value to prevent a large shift shock.

On the other hand, if FLAG3 = 1 in step 60, the measured T2 value is during automatic shifting or manual shifting based on the power pattern. For example, in the case of automatic shifting using the power pattern, the value shown in FIG. As shown, the inertia phase time T2 is longer due to the difference in vehicle speed than in the case of automatic shifting with economy butter even with the same throttle opening, and even in manual shifting, the vehicle speed may be different from automatic shifting with economy pattern. Inertia phase time target value T here
Since Z3 is suitable for the vehicle speed when shifting in the economy pattern as described above, the table data of the correction amount ΔD is not corrected and step 72 is performed.
After clearing Fl and AC3 to O, this subprogram is ended and the process returns to step 53.

Thereafter, in step 54, FLAG 2 is reset to 0, and timer T1. The value of T2 is reset to 0 and the next measurement is waited for.

By repeating this action (learning control), the line pressure solenoid drive duty correction amount ΔD adjusts the line pressure control solenoid drive duty D+ΔD during gear shifting so that the line pressure is at an appropriate value (inertia), regardless of individual differences in automatic transmissions or changes over time. Continuously correct the phase time T2 to a value such that it becomes the target value T2.), and control the line pressure during shifting to an appropriate value that does not cause a reduction in the life of the friction element or a large shift shock under any situation change. I can do it.

Moreover, according to the device in this example, the inertia phase time target value suitable for automatic shifting in the most frequently used economy pattern is used for learning control, and the inertia phase time target value suitable for automatic shifting in the most frequently used economy pattern is used for learning control. Since learning control is not performed during the inertia phase time, erroneous learning due to differences in vehicle speed during gear shifting can be prevented, and line pressure control during gear shifting can always be properly controlled.

Although the above description has been made based on the illustrated example, the present invention is not limited to the above-mentioned example. For example, learning control is performed not only for upshifting but also for downshifting, and it is determined whether or not the learning control is possible. You can do it like this.

(Effects of the Invention) Thus, according to the line pressure control device of the present invention, even when an automatic transmission selectively uses a plurality of shift patterns to perform automatic gear shifting or manual gear shifting, the gear shifting mode is maintained in a predetermined manner. Since learning control is performed only when the vehicle speed at the time of the shift or the throttle opening at that time is a predetermined value, it prevents erroneous learning due to differences in vehicle speed during the shift, Line pressure can always be controlled appropriately.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the line pressure control device of the present invention, Fig. 2 is a control system diagram of an automobile power train showing an embodiment of the device of the present invention, and Figs. 3 to 5 are a computer for speed change control on the same side. Figure 6 is a characteristic diagram of the line pressure control solenoid drive duty, Figure 7 is the instantaneous RA regarding the correction amount of the duty.
A diagram illustrating the data in M, FIG. 8 is a diagram showing the relationship between the timer measurement time and the line pressure control solenoid drive duty during gear shifting, and FIG. 9 is a diagram showing the solenoid drive duty indicated by α, β, and T in FIG. 8. Shift operation time chart when
FIG. 10 is a shift operation time chart showing the occurrence of an inertia phase during a shift. 1... Electronically controlled fuel injection engine 2... Automatic transmission 3... Differential gear 4... Drive wheels 5... Engine control computer 6... Engine rotation sensor 7... Vehicle speed sensor 8 ... Throttle sensor 9... Intake air amount sensor IO... Torque converter 11... Speed change gear mechanism 14... Speed change control computer 15... Control valves 15a, 15b... Shift for speed change control solenoid 1
6...Duty solenoid for line pressure control 17...
・Input rotation sensor 18...Output rotation sensor 19...Shift pattern selection switch 20...Inhibitor switch 1 Fig. 3 Fig. 6 Fig. 7 Fig. Throttle opening (TH) Fig. 8 Shifting line pressure Zollenoi FJ Kawara 舊鵞f ((0+A
D%) Figure 9

Claims (1)

[Claims] 1. Selectively hydraulically actuate various friction elements of the transmission gear mechanism using line pressure to select a predetermined gear, and change the operating friction elements to shift to other gears. An input rotation sensor and an output rotation sensor respectively detect the input rotation speed and the output rotation speed of the speed change gear mechanism of the automatic transmission, and based on the signals from these sensors, the inertia phase time measuring means The line pressure adjuster measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and controls the line pressure during the shifting so that the inertia phase time reaches the target value. In the control device, a shift mode signal output means for outputting a signal indicating whether or not the shift measured by the inertia phase time is a shift in a predetermined mode; A line pressure control device for an automatic transmission, characterized in that the line pressure control device for an automatic transmission is provided with a control enable/disable determining means for specifying control of the line pressure of the pressure adjusting means during shifting based on the inertia phase time.