JP2804105B2 - Line pressure control device for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a line pressure control device that corrects and controls a line pressure to obtain an appropriate shift in an automatic transmission.

2. Description of the Related Art Conventionally, as a line pressure control device of an automatic transmission, for example, as disclosed in Japanese Patent Publication No. 63-3183, the time of a shift performed by the operation of a friction element is measured, and the shift time is measured. Learning control of the line pressure to be supplied to the friction element so as to become a target value at the next shift, thereby suppressing the shift shock by keeping the shift time constant and appropriately suppressing the slip of the friction element. Things are known.

(Problems to be Solved by the Invention) By the way, even when the line pressure is learned and controlled as described above and the shift time is adjusted to a target value, it has been found that there are the following disadvantages.

In other words, there are two cases of shifting of the automatic transmission, that is, shifting between the friction element and the one-way clutch, and shifting between the friction element and the friction element. In the former case, the transfer of the engine torque is naturally and smoothly performed by the one-way clutch, but in the latter case, there is a shift in the switching timing between the two friction elements, so that the engagement with the releasing friction element is established. The change in the torque capacity (i.e., the transmission torque) of the friction element on the engagement side during the shift transition does not respond well, and as a result, first, even when the torque capacity of the friction element on the release side is sufficiently reduced, When the torque capacity of the friction element is small, the turbine speed temporarily increases and the speed increases. Secondly, when the torque capacity of the friction element on the engagement side at the time of torque transfer is excessive, the decrease in the turbine speed is accelerated and the turbine speed is retracted. When the turbine speed is increased or retracted, an excessive load is imposed on the engagement of the friction element, and the durability of the friction element is maintained even when the shift time is controlled to the target value as in the conventional case described above. And a disadvantage that reliability is lowered occurs.

The present invention has been made in view of such a point, and an object thereof is to give priority to constant control of the shift time in the case where the above-described abnormality in the upshift or retraction of the turbine speed occurs. The purpose is to prevent the abnormal phenomenon.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, two friction elements during a shift transition are prioritized over line pressure learning control for controlling a shift time to a target value. The line pressure is corrected and controlled so that the timing of torque transfer between them is appropriate.

That is, specifically, as shown in FIG. 1, the solution according to the first aspect of the present invention comprises a line pressure adjusting means 77 capable of arbitrarily adjusting the line pressure and one of two friction elements operated by the line pressure. Is changed from the disengaged state to the engaged state, and the other is changed from the engaged state to the disengaged state. The shift time detecting means 80 detects the time of the shift, and the shift time detected by the shift time detecting means 80 becomes the target value. Line pressure learning correction means 81 for learning and correcting the line pressure by controlling the line pressure adjustment means 77 as described above, and temporarily controlling the input side rotation speed by the input side rotation speed of the automatic transmission during the gear shifting. Abnormality detection means for detecting rise or sudden drop
82, when the abnormal-time detecting means 82 detects a temporary increase in the input-side rotational speed of the automatic transmission, the line pressure is increased by increasing the input-side rotational speed in preference to the line pressure learning and correcting means 81. On the other hand, when the amount is large, the line pressure is greatly increased. On the other hand, when a sudden drop in the input-side rotational speed of the automatic transmission is detected by the abnormal time detecting means 82, the line pressure is reduced in priority to the line pressure learning correcting means 81. It is assumed that a line pressure correcting means 83 is provided.

According to a second aspect of the present invention, there is provided a line pressure adjusting unit 77 capable of arbitrarily adjusting a line pressure, and switching one of two friction elements operated by the line pressure from a released state to a engaged state and releasing the other from the engaged state. A shift time detecting means 80 for detecting a shift time performed by switching to the state, and a line pressure adjusting means 77 for controlling the line pressure so that the shift time detected by the shift time detecting means 80 becomes a target value. A line pressure learning correction unit 81 for learning correction, and an abnormal time detection unit 82 for detecting a temporary increase in the input-side rotational speed based on the input-side rotational speed of the automatic transmission during the gear shift.
When the abnormal-time detecting means 82 detects a temporary increase in the input-side rotational speed of the automatic transmission, the line pressure is increased by the input-side rotational speed in preference to the line-pressure learning and correcting means 81. And a line pressure correcting means 83 that increases the larger the value is.

According to a third aspect of the present invention, there is provided a line pressure adjusting means 77 capable of arbitrarily adjusting a line pressure, and switching one of two friction elements operated by the line pressure from a released state to a engaged state and releasing the other from the engaged state. A shift time detecting means 80 for detecting a shift time performed by switching to the state, and a line pressure adjusting means 77 for controlling the line pressure so that the shift time detected by the shift time detecting means 80 becomes a target value. A line pressure learning correction means 81 for performing learning correction, and an abnormal time detection means 82 for detecting a sharp drop in the input-side rotational speed based on the input-side rotational speed of the automatic transmission during the gear shift.
And a line pressure correction unit 83 that lowers the line pressure in preference to the line pressure learning correction unit 81 when a sudden drop in the input-side rotation speed of the automatic transmission is detected by the abnormality detection unit 82. Shall be provided.

(Operation) With the above configuration, according to the first to third aspects of the present invention, when the turbine speed temporarily increases during a shift transition, the torque capacity of the engagement-side friction element is small and the turbine speed is reduced. Since it is determined that blow-up has occurred, the line pressure can be corrected by the line pressure correcting means 83 so as to increase the line pressure as the amount of increase in the turbine speed increases. Is increased in accordance with the rise of the turbine speed, and the turbine speed is effectively prevented from rising at the next shift.

Conversely, if the turbine speed drops abruptly, it is determined that the torque capacity of the friction element on the fastening side at the time of torque transfer is too large and the turbine speed has been retracted, and the line pressure is corrected to be low. As a result, the torque capacity of the engagement-side friction element at the time of torque transfer is reduced, and the pull-in of the turbine speed at the next shift is prevented.

When the above line pressure correction is performed, the direction of the line pressure correction may be different from the direction of the line pressure learning control. Since the learning control of the line pressure is performed so that only the shift time is set to the target value, the shift time converges as close as possible to the target value as long as the above phenomenon does not occur.

(Effects of the Invention) As described above, according to the line pressure control device of the automatic transmission according to the first to third aspects of the present invention, the shift time is set within a range in which the turbine speed does not rise or fall during the shift transition. Learning control of the line pressure so as to approach the target value, the shift shock can be effectively suppressed while the occurrence of the above-mentioned phenomenon can be prevented, and the slippage of the friction element can be suppressed appropriately, so that an appropriate shift is always performed. be able to.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows the configuration of the automatic transmission 10. The automatic transmission 10 shown in FIG. 1 has four forward gears and one reverse gear, 15 is an engine output shaft, and 16 is a pump connected to the engine output shaft 15.
This is a torque converter including 16a, a stator 16b, and a turbine 16c. The stator 16b is provided so as to be fixed to the case 18 via a one-way clutch 17 for preventing the stator 16b from rotating in the opposite direction to the turbine 16c. Reference numeral 20 denotes a transmission gear unit connected to a converter output shaft 16d connected to a turbine 16c of the torque converter 16.

The transmission gear device 20 includes a Ravigneaux-type planetary gear mechanism 22 therein. The planetary gear mechanism 22 includes a small-diameter sun gear 23 and a large-diameter sun gear 24 arranged in front and rear, and the small-diameter sun gear 24.
The short pinion gear 25 meshes with the long pinion gear 25, the long pinion gear 26 meshes with the large diameter sun gear 24 and the short pinion gear 25, and the ring gear 27 meshes with the long pinion gear 16. The small-diameter sun gear 23 includes a forward clutch 30 and a clutch 30
Are connected in series to the output shaft 16d of the torque converter 16 via a first one-way clutch 31 for preventing reverse driving of the converter output shaft 16d. And
Forward clutch 30 and first one-way clutch 31
The coast clutch 32 is connected and arranged in parallel in a system path in which the and are connected in series. The large-diameter sun gear 24
Are a 2-4 brake 33 disposed diagonally rearward and a reverse clutch 34 disposed rearward of the 2-4 brake 33.
Through the output shaft 16d of the torque converter 16. In addition, the long pinion gear 26 has a low & reverse brake 36 for fixing the long pinion gear 26 via a rear carrier 35, and a second allowing the rotation of the long pinion gear 26 in the same direction as the engine output shaft 15.
The one-way clutch 37 is connected in parallel, and the front carrier 38 is connected to the output shaft 16d of the torque converter 16 via a 3-4 clutch 39. Further, the ring gear 27 is connected to an output gear 40 disposed in front of the ring gear 27. In the figure, reference numeral 42 denotes a lock-up clutch that directly connects the engine output shaft 15 and the converter output shaft 16d, and 43 denotes an oil pump driven by the engine output shaft 15 via the intermediate shaft 44.

The following table shows the operating states of the clutches and brakes at each shift speed in the above configuration.

Next, a hydraulic circuit for operating each friction element of the automatic transmission 10 is shown in FIG. In the figure, reference numeral 70 denotes a pressure regulating valve that regulates the hydraulic pressure from an oil pump 71 driven by the engine 1 to generate a line pressure, and 72 denotes a manual valve that is linked to a select lever that is manually operated by a driver. The frictional element of the automatic transmission 10 is connected to the manual valve 71 via a plurality of shift valves (not shown) so that oil can be supplied and discharged.

The pressure regulating valve 70 includes a spool 70a and an urging force S
a spring 70b that urges the right side in the figure with p,
The hydraulic pressure P from the oil pump 71 acts on the right end of the spool 70a in the figure, and the control pressure for adjusting the line pressure acts on the left oil chamber 70c. Then, the total pressure T of the control pressure and the urging force Sp
Spool due to the relationship between (target line pressure) and hydraulic pressure P
The hydraulic pressure P is adjusted to the total pressure T (target line pressure) by finely moving the 70a left and right to adjust the communication / cutoff between the line pressure passage 72 and the drain passage 73.

Thus, as a configuration for generating the control pressure, the oil chamber 70c
An oil passage 75 is communicatively connected to the oil passage 75. The oil passage 75 is acted upon by a hydraulic pressure that has been reduced by the pressure reducing valve 76 from the discharge pressure of the oil pump 71, and a duty solenoid valve SO
L is connected and the duty solenoid valve SOL is ON-OFF
A line pressure adjusting means 77 is provided which adjusts the control pressure by adjusting the opening ratio of the oil passage 75 to the oil tank by operation, thereby adjusting the line pressure.

Next, the line pressure control shown in FIG. 4 will be described. In step S1, it is checked whether or not a shift is being performed. If the determination is NO, the line pressure control outside the shift is performed in step S2, that is, the line pressure is controlled. Is controlled to a pressure value corresponding to the throttle opening and the turbine speed. On the other hand, if the determination in step S1 is YES, a routine of the line pressure control during the shift shown in FIG. 5 is executed in step S3, and it is checked in step S4 whether the upshift is performed. If the determination in step S4 is YES, the routine of the line pressure control by learning the shift time shown in FIG. 9 is executed in step S5, and if the determination in step S4 is NO (shift down), The line pressure is corrected by learning the number, that is, the line pressure is corrected in accordance with the deviation between the target turbine rotation speed after the shift and the turbine rotation at the time when the shift is substantially completed.

Next, the line pressure control during the shift shown in FIG. 5 will be described.
In this routine, first, at step SA1, it is checked whether or not an upshift is performed. In the case of an upshift, the throttle opening is read in step SA2, and in step SA3, the line pressure Pl is determined according to the speed before and after the shift and the throttle opening.
To determine. This makes it possible to appropriately adjust the line pressure at the time of upshifting. In other words, the shock at the time of upshifting involves the engine output and the shift speed in accordance with the throttle opening. In particular, the shared torque and the capacity of the friction elements that are switched at the time of shifting differ depending on the shift speed. If the line pressure is set irrespective of the above, it is not possible to optimally adjust the fastening speed and the like for all the shift speeds only by setting the characteristics of the accumulator in the hydraulic circuit. Therefore, in the present embodiment, as shown in FIG. 6 (a), for the line pressure at the time of upshifting, a value corresponding to the line pressure is mapped for each combination of the gear positions before and after the shift, and is stored in the memory in the control unit. It is stored, and the line pressure is determined from this map. Accordingly, conventionally, as shown by the two-dot chain line in FIG. 6B, the line pressure is set to a relatively high value that can prevent slippage of all the friction elements. As shown by the solid line, the line pressure is set to a value lower than the conventional one and different depending on the shift speed.

Further, if the determination in step SA1 is NO, that is, if the shift is down, it is checked whether or not the shift is down from the third speed to the second speed in step SA4, and if the determination is YES, the line in steps SA5 to SA8 is determined. Calculate the pressure and press NO
In the case of, the line pressure control outside the shift (Step S2 in FIG. 4)
Move on to This is because during the downshift from the third speed to the second speed, the 3-4 clutch 39 is released and the
-4 Since the brake 33 is engaged, adjustment of the engagement timing is required.
This is because only the release of the -4 clutch 39 or the 2-4 brake 33 is performed, and adjustment of the engagement timing by the line pressure is not required.

As a process at the time of downshifting from the third speed to the second speed, the turbine speed is read in step SA5, and the baseline pressure Plo is determined in step SA6 according to the turbine speed. In other words, at the time of downshifting from the third speed to the second speed, the 2-4 brake 33 is engaged when the turbine speed reaches an appropriate speed by the disengagement operation of the 3-4 clutch 39. Since the timing varies depending on the turbine rotational speed, as shown in FIG. 7, the baseline pressure Plo corresponding to the turbine rotational speed is mapped and stored in a memory in the control unit, and the baseline pressure Plo is obtained from this map. Like that.

In steps SA7 and SA8 subsequent to step SA6, the line pressure is corrected in accordance with the throttle opening change speed calculated from the throttle opening detection values a plurality of times. That is, when the throttle opening change speed increases, the engine speed ( Since the rising speed of the turbine speed increases, the correction timing Ca corresponding to the throttle opening change speed is determined as shown in FIG. The final line pressure Pl is obtained by multiplication.

Subsequent to step SA3 or step SA8, the duty ratio of the duty solenoid valve SOL is determined in step SA9, the solenoid drive frequency is set in step SA10, and the ON time of the solenoid valve is calculated in step SA11. Drives the duty solenoid valve SOL.

Next, the line pressure correction by learning the shift time in FIG. 9 will be described. This routine corrects the line pressure Pl obtained in step SA3 in FIG. 5 at the time of upshifting, and at the time of upshifting, the rotational speed of the turbine after the shift is changed as the frictional element is gradually engaged. In this case, the line pressure is corrected in accordance with the shift time since the shift speed is reduced to the number and the shift time is related to the engagement speed of the friction element. In this routine, the turbine speed is read in step SB1, and the change rate ΔNT of the turbine speed is calculated in step SB2. Then, in step SB3, the change rate ΔNT is compared with a relatively large set value A. If ΔNT ≧ A, it is determined that the turbine speed is in the idling state, and in step SB4, the correction coefficient shown in FIG. The correction coefficient CΔN is searched based on the map, and is set to a larger value as the change rate ΔNT of the turbine rotation speed is larger.
l is multiplied and corrected by the correction coefficient CΔN to increase the line pressure.

On the other hand, if it is determined in step SB3 that the air blowing state is not ΔNT <A, the flow waits for the set time t to elapse in step SB6 in order to determine whether or not the turbine speed is retracted. , The change rate of the turbine speed ΔNT is compared with a relatively large value −B as a negative value, and ΔNT
If .ltoreq.-B, it is determined that the turbine rotational speed is retracted, and in step SB8, a correction coefficient C.DELTA.N1 is retrieved based on the correction coefficient map shown in FIG.
Is set to a smaller value as the value is larger as a negative value, and in step SB5, the baseline pressure Pl is multiplied and corrected by the above-described correction coefficient CΔN1 to lower the line pressure.

If ΔNT> −B in step SB7,
Subsequently, at step SB9, the rate of change of the turbine speed is set to ΔNT
Is determined to be within a predetermined range (−C ≦ ΔNT ≦ D) near the zero value, and if it is within this range, it is determined that the torque is being retracted, and the correction of FIG. The correction coefficient CΔN2 is searched based on the coefficient map, and the smaller the change rate ΔNT of the turbine speed within this predetermined range (−C ≦ ΔNT ≦ D), the smaller the value is set, and the baseline pressure Pl is set at step SB5. And the line pressure is reduced by multiplication correction by the correction coefficient CΔN2.

If the determination in step SB9 is NO, that is, if there is no idling of the turbine speed, no pull-in, and no pull-in of torque, learning control of the line pressure is performed so that the shift time is set to the target value in step SB11 and thereafter. It shall be.

That is, after calculating the target turbine speed after shifting from the turbine speed before shifting in step SB11, the difference between the turbine speed and the target turbine speed is less than or equal to a predetermined value in step SB12, and It is determined whether or not the shift is completed based on whether or not a condition that the rate of change is equal to or less than a predetermined value is satisfied.
The shift time T is calculated in step S3.

Thereafter, in step SB14, a deviation ΔT between the actual shift time T and the target value To is calculated, and then in step SB15, the correction coefficient Ct in FIG. 14 is calculated in accordance with the speed time deviation ΔT. That is, when the shift ΔT is close to zero, Ct = 1 is set. However, as shown in FIG.
When T is a negative value, Ct <1 is set to decrease the line pressure, and when the shift time T2 is long and the ΔT is a positive value, Ct> 1.
To increase the line pressure.

Then, in step SB16, the obtained line pressure Pl is corrected to Pl = Pl × Ct with the correction coefficient Ct, and the corrected line pressure Pl is used for the next control.

Next, a description will be given of the line pressure correction by learning the blow-up rotation speed in step S6 in FIG. 4 with reference to FIG. At step SE1, the turbine speed is read, and at step SE2
Then, the target turbine speed N0 after the speed change is calculated based on the turbine speed before the speed change.

Thereafter, in step SE3, the change rate of the turbine speed is calculated, and in step SE4, it is determined whether or not the change rate of the turbine speed has become equal to or less than a predetermined value corresponding to the end of the shift (that is, points x0 and x1, in FIG. 16). x2), and if the end of the shift is reached, in step SE5, the turbine rotational speed NS at that time is determined.
Is read, and in step SE9, the difference between the turbine speed NS and the target turbine speed N0 is calculated as the blow-up speed ΔN (=
NS−N0).

Thereafter, in step SE7, the correction coefficient Cn is calculated based on the correction coefficient map shown in FIG.
Is increased to 1.0 or more as the blow-up rotation speed ΔN is a positive value and larger,
It is calculated to be 1.0 or less as the blow-up rotation speed ΔN is larger as a negative value. In step SE8, the base line pressure Plo is multiplied and corrected by the correction coefficient Cn, and the corrected line pressure Plo is corrected.
Is used for control at the time of the next downshift, thereby preventing the turbine speed from being blown up or drawn in at the downshift shown by the dashed line and the broken line in FIG.

Therefore, in steps SB12 and SB13 of the control flow of FIG. 9, the shift is started by switching one of the two friction elements operating at the line pressure from the disengaged state to the engaged state and switching the other from the engaged state to the disengaged state. The shift time detecting means 80 is configured to detect a shift time T from time to end. Further, in steps SB14 to SB16 of the control flow, a correction coefficient Ct is calculated so that the shift time T detected by the shift time detecting means 80 becomes the target value T0, and the line pressure Pl is corrected by the coefficient Ct. Line pressure
Line pressure learning correction means 81 for learning control of the line pressure adjustment means 77 (particularly the duty solenoid valve SOL) so as to be Pl.
Is composed.

Steps SB1 to SB3, SB6, SB7,
The SB9 constitutes an abnormal time detecting means 82 for detecting a temporary increase or a sharp drop in the turbine speed based on the turbine speed (input side speed) of the automatic transmission 10 during shifting. I have. Further, when the abnormal time detecting means 82 detects a temporary increase in the turbine speed of the automatic transmission 10 in steps SB4, SB8, and SB10 of the same control flow, a correction coefficient CΔN (CΔN ≧ 1) is set. As the amount of increase in the turbine speed increases, the line pressure increases greatly. When a sharp decrease in the turbine speed is detected, the correction coefficient CΔN1 (CΔN1 ≦ 1) is set to reduce the line pressure. A line pressure correcting means 83 is configured to correct the line pressure so as not to cause the above-mentioned phenomenon by giving priority to the line pressure learning correcting means 81.

Therefore, in the above embodiment, as can be seen from the above table, at the time of the 2 → 3 shift-up shift, the 2-4 brake 33 is disengaged and the 3-4 clutch 39 is engaged, and the frictional element is interposed between the two friction elements. Delivery of torque is performed.

In that case, the change rate ΔNT of the turbine speed is ΔNT ≧ A
In the case where the turbine speed is rising as shown by the broken line in FIG. 18, the correction coefficient CΔN is set to CΔN> 1, and the line pressure Pl is calculated based on the calculation formula of Pl = Pl × CΔN. And is highly corrected. As a result, as shown in FIG. 19, the 3-4 clutch 39 at the time of torque transfer at the time of the next gear shift is used.
Since the torque capacity of the (friction element on the engagement side) increases, the torque capacity and the engine torque are almost equally opposed to each other, thereby preventing the turbine speed from being blown at the next shift.

Conversely, when the rate of change of the turbine speed is ΔNT ≦ −B and the turbine speed is drawn in as shown by the dashed line in FIG. 18, the correction coefficient CΔN1 is set to CΔN1 <1, and Since the line pressure Pl is corrected to be low, the torque capacity of the friction element on the engagement side at the time of the next torque transfer is reduced, thereby preventing the turbine speed from being pulled in at the next shift.

Further, when the rate of change of the turbine speed is −C ≦ ΔNT ≦ D and the torque is drawn as indicated by the two-dot chain line in FIG. 18, the correction coefficient CΔN2 is set to CΔN2 <1. Therefore, the line pressure Pl is corrected to be low. As a result, the torque capacity of the 2-4 brake 33 (released friction element) at the time of shifting is quickly reduced, and the engagement operation of the engagement friction element is performed gently.
The situation where the two friction elements are firmly fastened at the same time is eliminated, and the pull-in of torque is prevented.

The line pressure is corrected and controlled so that the speed change time T approaches the target value T0 by learning control after preventing the above-described turbine speed increase, pull-in, and torque pull-in phenomena. The shift time T approaches the target value as much as possible within a range where the phenomenon does not occur.
Therefore, it is possible to obtain an appropriate shift state by suppressing shift shock and slippage of the friction element while preventing the turbine speed from rising, pulling in, and pulling in torque during a shift transition.

In the above embodiment, the present invention is applied to the case of shifting up, but it is needless to say that the present invention can be similarly applied to the case of shifting down.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 19 show an embodiment of the present invention. FIG. 2 is a skeleton diagram of an automatic transmission, FIG. 3 is a hydraulic circuit diagram for adjusting line pressure, and FIGS. FIG. 6 is a flowchart showing line pressure control, FIG. 6 is a diagram showing line pressure characteristics according to a shift speed and a throttle opening during upshifting, and FIG. 7 is a line according to turbine speed during 3 → 2 downshifting. FIG. 8 is a diagram showing a pressure map, FIG. 8 is a diagram showing a correction coefficient characteristic of a line pressure with respect to a throttle opening change speed, FIG. 9 is a flowchart showing learning control of a line pressure for setting a shift time to a target value, and FIG. Figure 10 is a diagram showing the correction coefficient characteristics of the line pressure at the time of turbine speed blow-up,
FIG. 11 is a diagram showing a correction coefficient characteristic of the line pressure when the turbine rotational speed is pulled, FIG. 12 is a diagram showing a correction coefficient characteristic of the line pressure when the torque is pulled, and FIG. FIG. 14 is an explanatory diagram showing how the number changes, FIG. 14 is a diagram showing a correction coefficient characteristic corresponding to a shift of a shift time from a target value, FIG.
FIG. 16 is a flowchart showing learning correction of the line pressure according to the blow-up rotation speed, FIG. 16 is an explanatory diagram showing a state of the turbine speed being blown up at the end of the shift, and FIG. 17 is a target of the blow-up speed. FIG. 18 is a diagram showing a correction coefficient characteristic of a line pressure according to a deviation with respect to a value, FIG. 18 is an explanatory diagram of a state of a change in a turbine speed during a shift transition, and FIG.
It is explanatory drawing of a mode of a change of the torque capacity of a brake band and the torque capacity of a 3-4 clutch. 10… Automatic transmission, SOL… Duty solenoid valve, 77 ……
Line pressure adjusting means, 80: Shift time detecting means, 81: Line pressure learning correcting means, 82: Abnormality detecting means, 83: Line pressure correcting means.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (3)

(57) [Claims] A line pressure adjusting means capable of arbitrarily adjusting a line pressure, and one of two friction elements operated by the line pressure being switched from a disengaged state to a fastened state, and the other being switched from a fastened state to a disengaged state. A shift time detecting means for detecting a shift time to be changed, and a line pressure learning correcting means for learning and correcting the line pressure by controlling the line pressure adjusting means so that the shift time detected by the shift time detecting means becomes a target value. Abnormality detecting means for detecting a temporary increase or sudden drop in the input-side rotational speed based on the input-side rotational speed of the automatic transmission at the time of the shifting, and an automatic transmission using the abnormal-time detecting means. When a temporary increase in the input-side rotational speed is detected, the line pressure is increased greatly as the amount of increase in the input-side rotational speed is increased in preference to the line pressure learning correction means. A line pressure correction unit that reduces the line pressure in preference to the line pressure learning correction unit when a sudden drop in the input-side rotation speed of the automatic transmission is detected by the abnormality detection unit. Line pressure control device for an automatic transmission. 2. A line pressure adjusting means capable of arbitrarily adjusting a line pressure, and one of two frictional elements operated by the line pressure being switched from a disengaged state to a fastened state and the other being switched from a fastened state to a disengaged state. A shift time detecting means for detecting a shift time to be changed, and a line pressure learning correcting means for learning and correcting the line pressure by controlling the line pressure adjusting means so that the shift time detected by the shift time detecting means becomes a target value. Abnormality detecting means for detecting a temporary increase in the input-side rotational speed based on the input-side rotational speed of the automatic transmission at the time of the shift, and an input-side rotational speed of the automatic transmission based on the abnormal-time detecting means. When a temporary rise in is detected,
A line pressure control unit for automatically transmitting the line pressure, wherein the line pressure correction unit is configured to increase the line pressure in proportion to the increase in the input-side rotational speed. 3. A line pressure adjusting means capable of arbitrarily adjusting a line pressure, and switching by switching one of two friction elements operated by the line pressure from a disengaged state to a fastened state and switching the other from a fastened state to a disengaged state. A shift time detecting means for detecting a shift time to be changed, and a line pressure learning correcting means for learning and correcting the line pressure by controlling the line pressure adjusting means so that the shift time detected by the shift time detecting means becomes a target value. Abnormality detecting means for detecting a sudden drop in the input-side rotational speed based on the input-side rotational speed of the automatic transmission at the time of the shift, and detecting the input-side rotational speed of the automatic transmission by the abnormal state detecting means. When a sudden drop is detected,
A line pressure control device for an automatic transmission, comprising: a line pressure correction unit that reduces the line pressure prior to the line pressure learning correction unit.