JPH08312772A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE: To prevent the occurrence of a trouble, such as complication of control and the increase of a memory using amount, by a method wherein when a shift to a first speed is effected, the fastening force of a friction element during next and following shifts to the first speed is corrected by using a correction value decided with a shifting time of the shift, and the correction value is converted into a new correction value and used during a shift to a second speed. CONSTITUTION: When a shift to a first speed is effected by a control unit 100 or a hydraulic control circuit 80, a learning correction value for the fastening force of a friction element is decided. The fastening force of a friction element during next and following shifts to a first speed is corrected by using the learning correction value, and by converting the correction value, the converted value is used during a shift to a second speed. This constitution simplifies control by effecting correction of fastening forces during a shift to the first speed and during a shift to the second speed and saves an amount of using memories to store the correction values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission,
In particular, the present invention relates to learning control of the engagement force of the friction element during gear shifting.

[0002]

2. Description of the Related Art An automatic transmission mounted on an automobile is a combination of a torque converter to which an engine output is input and a speed change gear mechanism driven by the output of the torque converter, and a power transmission path of the speed change gear mechanism. It is configured to automatically shift to a predetermined gear according to the driver's request and driving state by switching by selectively engaging a plurality of friction elements such as clutches and brakes. The machine is provided with a hydraulic control circuit that generates a hydraulic pressure for engaging the friction element.

In this case, if the oil pressure generated by this oil pressure control circuit is too high, the engagement force becomes relatively large with respect to the input torque to the friction element at the time of gear shifting in which the friction element is engaged by the oil pressure. If the hydraulic pressure is too low, on the other hand, the fastening force of the friction element will be insufficient and the gear shifting time will be lengthened, and the durability of the friction element will be impaired. The shift feeling will deteriorate.

On the other hand, focusing on the fact that the input torque to the friction element corresponds to the output torque of the engine, the line pressure which is the original pressure of the hydraulic pressure for engagement, for example, the throttle valve for controlling the engine output torque is controlled. The operating pressure or the fastening force of the friction element is made to correspond to the input torque to the friction element by adjusting according to the opening degree.

However, this type of automatic transmission has individual differences due to variations in various constituent elements.
Since there are individual differences in the engine combined with the automatic transmission, in order to obtain the optimum shift characteristics, the above hydraulic pressure or engaging force must be tuned at the manufacturing stage for each combination of the engine and the automatic transmission. Instead, complicated work is required. Further, even if the optimum gear shift characteristic is set in the manufacturing stage, the gear shift characteristic changes due to changes over time such as wear of friction elements and deterioration of hydraulic oil.

To solve this problem, for example, Japanese Patent Laid-Open No. 1-193.
According to Japanese Patent Laid-Open No. 445, a technique for learning control of the line pressure at the time of shift-up gear shift, which causes a large gear shift shock, is disclosed. This technique is to compare the time actually required for the gear shifting operation with the target gear shifting time and learn and correct the line pressure at the next gear shifting so that the actual gear shifting time approaches the target gear shifting time. Specifically, if the actual shift time is too long for the target shift time, the line pressure is increased during the next shift, and if the actual shift time is too short, the line pressure is decreased during the next shift. It is controlled to do so. According to this, the optimum gear shift characteristic is maintained without being affected by the individual difference between the automatic transmission and the engine, the change over time of each component, and the like.

The shift-up shift is roughly divided into a so-called schedule-up shift that is performed as the vehicle speed increases and a so-called back-out shift that is performed as the accelerator pedal is returned. The latter back-out shift is performed. Gear shifting is performed in an unstable state in which the torque fluctuation during the transition from acceleration to deceleration is large.Therefore, it may not be possible to correctly learn the gear shifting time. It is customary to prohibit the learning control of the line pressure as described above (see, for example, JP-A-2-42254).

On the other hand, in this type of automatic transmission, for example, two different gear stages may be achieved by engaging the same friction element. For example, an automatic transmission that automatically shifts between 1st and 4th speed may include a friction element that is engaged at 2nd speed and 4th speed and a friction element that is engaged at 3rd speed and 4th speed. In this case, in the first speed state in which both the second and fourth speed friction elements and the third and fourth speed friction elements are released, when the second and fourth speed friction elements are engaged, a shift-up shift from the first speed to the second speed is performed. In the third speed state in which only the friction elements for the third and fourth speeds are engaged,
When the high speed friction element is engaged, the upshift is performed from the third speed to the fourth speed.

When performing the above-described line pressure learning control in such an automatic transmission, conventionally,
The fact is that this learning control is performed independently for each shift.

[0010]

However, when learning control is performed independently of each other during the 1-2 shift and the 3-4 shift in which the same friction element is engaged as described above,
For example, the following problems may occur.

That is, since the schedule up shift from the 1st speed to the 2nd speed is performed in a relatively low vehicle speed range, the learning frequency is high, but the schedule up shift from the 3rd speed to the 4th speed is in the high vehicle speed range (for example, about an hour speed). Since it is performed at 120 km / h), learning opportunities are insufficient, learning correction that does not match the state of the automatic transmission or engine at that time is not performed, and eventually the required control for the fastening force of the friction element is performed. The accuracy cannot be obtained.

On the other hand, these gear shifts are performed by engaging the same friction element, so that learning for this friction element is repeated. for that reason,
This causes troubles such as complicated control and an increase in memory capacity for storing learning data.

In view of the above, the present invention relates to an automatic transmission constructed so that two different gears can be achieved by engaging the same friction element, and the control becomes complicated and the memory usage increases. It is an object of the present invention to avoid the above problem and to improve the control accuracy for the engaging force of the friction element by appropriately performing the learning correction at any shift.

[0014]

In order to solve the above problems, the present invention is characterized by using the following means.

First, the invention according to claim 1 (hereinafter referred to as the first invention) is an automatic transmission that is achieved by engaging the same friction element in the first gear and the second gear. , An actual shift time detecting means for detecting an actual shift time at the time of shifting to the first shift stage, and at the time of shifting to the first shift stage from the next time on the basis of the actual shift time and the target shift time. Correction value determining means for determining a correction value for the fastening force of the friction element, and first correction means for correcting the fastening force for the friction element when shifting to the first gear according to the determined correction value. , A correction value conversion means for converting the correction value into a correction value of the fastening force at the time of shifting to the second gear, based on the relationship between the fastening force at the first gear and the fastening force at the second gear. And the friction value at the time of shifting to the second speed using the converted correction value. Characterized in that a second correction means for correcting the fastening force of the unit.

Further, in the invention according to claim 2 (hereinafter referred to as the second invention), as in the case of the first invention, the same friction element is engaged in the first gear and the second gear. In the automatic transmission achieved by, the first actual shift time detecting means for detecting the actual shift time when shifting to the first shift stage, and the next and subsequent times based on the actual shift time and the target shift time. First correction value determining means for determining a correction value for the fastening force of the friction element during the shift to the first shift speed, and the friction during the shift to the first shift speed according to the determined correction value. First correction means for correcting the fastening force of the element, second actual shift time detection means for detecting the actual shift time when shifting to the second shift stage, and the actual shift time and the target shift time Based on and, The second correction value determination means determines the correction value of the binding force, and the first correction value determination means determines the relationship between the engagement force in the first gear and the engagement force in the second gear. A correction value conversion means for converting the correction value thus obtained into a correction value for the fastening force at the time of shifting to the second gear, and the correction value determined by the second correction value determination means and the correction value conversion means. Second correction means for correcting the engaging force of the friction element at the time of shifting to the second shift stage using the converted correction value is provided.

Further, the invention according to claim 3 (hereinafter, referred to as the third
In the automatic transmission that is achieved by engaging the same friction element between the first speed change step and the second speed change step, the actual shift time at the time of shifting to the first speed change step is also described. First actual shift time detecting means for detecting, and first determining the correction value of the engagement force of the friction element at the time of shifting to the first shift stage after the next based on the actual shift time and the target shift time. Correction value determining means, second actual shift time detecting means for detecting the actual shift time when the gear is shifted to the second shift stage, and the next and subsequent ones based on the actual shift time and the target shift time. Second correction value determining means for determining a correction value for the fastening force of the friction element during the shift to the second shift speed;
The correction value determined by the second correction value determining means based on the relationship between the engagement force at the shift speed and the engagement force at the second shift speed is used to correct the fastening force at the time of shifting to the first shift speed. The correction value determined by the first correction value determination means based on the relationship between the first correction value conversion means for converting the value into a value and the engagement force at the first speed and the engagement force at the second speed. Second correction value conversion means for converting the value into a correction value for the fastening force during shifting to the second gear, the correction value determined by the first correction value determination means, and the first correction value First correction means for correcting the engaging force of the friction element at the time of shifting to the first speed using the correction value converted by the conversion means, and correction determined by the second correction value determination means. Value and the correction value converted by the second correction value conversion means are used to shift the friction element at the time of shifting to the second shift speed. Characterized in that a second correction means for correcting the binding force.

The invention according to claim 4 (hereinafter, referred to as the fourth
In any one of the above-mentioned first to third inventions, the friction element has two engaging hydraulic chambers, and the engaging force at the first speed and the engaging force at the second speed. The correction value conversion means for converting the correction value based on the relationship with is configured to convert the correction value based on the pressure receiving areas of the two fastening hydraulic chambers of the friction element.

The invention according to claim 5 (hereinafter referred to as the fifth invention) is such that the friction element in the fourth invention is a hydraulic chamber for engagement and a hydraulic chamber to which hydraulic pressure is supplied at the second speed.
It is a 2-4 brake having a hydraulic chamber to which hydraulic pressure is supplied at high speed.

[0020]

According to the above inventions, the following effects can be obtained.

First, according to the first aspect of the invention, based on the actual shift time and the target shift time when shifting to the first shift stage, the frictional element of the frictional element at the time of shifting to the first shift stage after the next time is changed. Since the correction value for the engagement force is determined, and the correction value is converted by the conversion means into the correction value for the engagement force of the friction element at the time of shifting to the second shift stage based on a predetermined relationship, for example, If a gear stage that is frequently executed is selected as the first gear stage, the correction value can be obtained with high accuracy in conformity with the state of the automatic transmission or engine at that time. The engagement force of the friction element is appropriately controlled during any gear shift to the second gear.

Further, since only the correction value of the engagement force at the time of shifting to the first speed is required to be stored and held, the control for that purpose is simplified and the amount of memory used is saved. Become.

Next, according to the second aspect of the present invention, the correction value of the engagement force is determined even during the shift to the second shift stage, so that at the time of shifting to the second shift stage, the correction value of the preceding force is used. The correction value determined at the time of shifting to the second shift stage and the correction value determined at the time of shifting to the first shift stage prior to the shift stage and converted by the conversion means are used.
Even if the frequency of shifting to the second shift stage is low, the fastening force at the time of shifting to the second shift stage can be controlled using the correction value suitable for the state of the automatic transmission or engine at that time. Therefore, high accuracy of the control is ensured.

Further, according to the third aspect of the invention, the correction values are respectively determined when shifting to the first and second shift speeds, and
Since these correction values are converted to each other and used when shifting to the other shift stage, at the time of shifting to any shift stage, the correction value determined at the previous shift to that shift stage and the other The correction value determined at the time of shifting to the shift stage and converted by the conversion means is used together, and therefore, the control accuracy of the engagement force is further improved during both shifts.

According to the fourth aspect of the invention, the friction element that is engaged at the first and second speeds has two engaging hydraulic chambers, and the correction value converting means adjusts the pressure receiving areas of these hydraulic chambers. Since the correction value is converted based on the above, in any of the first to third aspects of the invention, the correction value can be accurately converted by simple calculation.

Further, according to the fifth aspect of the invention, each of the above aspects of the invention is applied to the 2-4 brake that is engaged in the 2nd speed and the 4th speed, so that the schedule upshift to the 4th speed is performed in the high vehicle speed range. Even though the frequency is low, the fastening force can be controlled with high accuracy.

[0027]

Embodiments of the present invention will be described below.

As shown in FIG. 1, an automatic transmission 10 according to this embodiment has a torque converter 20 connected to an engine output shaft 1, a speed change gear mechanism 30 to which the output torque is input, and the mechanism 30. Has a plurality of friction elements 41 to 46 such as clutches and brakes for switching the power transmission paths and one-way clutches 51 and 52, and by these, each range of D, S, L and R as a traveling range and a D range. The 1st to 4th speeds in the S range, the 1st to 3rd speeds in the S range, the 1st to 2nd speeds in the L range, and the reverse speed in the R range are obtained.

The torque converter 20 is a pump 2 fixed in a case 21 connected to the engine output shaft 1.
2 and the pump 22 disposed so as to face the pump 22.
The turbine 23 driven by the hydraulic oil by the one-way clutch 2 between the pump 22 and the turbine 23.
4 is provided between the case 21 and the turbine 23, which is supported by the transmission case 11 via the No. 4 and performs a torque increasing action, and the engine output shaft 1 and the turbine 23 through the case 21. And a lockup clutch 26 that directly connects The rotation of the turbine 23 is output to the transmission gear mechanism 30 side via the turbine shaft 27.

A pump shaft 12 penetrating through the turbine shaft 27 is connected to the engine output shaft 1, and an oil pump 13 provided at the end of the transmission 10 opposite to the engine is connected by the shaft 12. It is designed to be driven.

On the other hand, the speed change gear mechanism 30 is constituted by a Ravigneaux type planetary gear device, and has a small diameter small sun gear 31 loosely fitted on the turbine shaft 27.
A large-diameter large sun gear 3 which is also loosely fitted on the turbine shaft 27 on the engine side of the sun gear 31.
2, a plurality of short pinion gears 33 meshed with the small sun gear 31, a half part on the engine side is meshed with the short pinion gear 33, and a half part on the non-engine side is meshed with the large sun gear 32. 34, a pinion carrier 35 that rotatably supports the long pinion gear 34 and the short pinion gear 33, and a ring gear 36 meshed with the long pinion gear 34.

A forward clutch 41 and a first one-way clutch 51 are provided in series between the turbine shaft 27 and the small sun gear 31, and a coast clutch 42 is provided in parallel with these clutches 41, 51. In addition to being installed, the turbine shaft 2
3-4 clutch 4 between 7 and pinion carrier 35
3 is provided, and a reverse clutch 44 is provided between the turbine shaft 27 and the large sun gear 32.

Between the large sun gear 32 and the reverse clutch 44, a 2-4 brake 45, which is a band brake for fixing the large sun gear 32, is provided, and the pinion carrier 35 and the transmission case 11 are provided. A second one-way clutch 52 that receives the reaction force of the carrier 35 and a low reverse brake 46 that fixes the carrier 35 are provided in parallel between them. The ring gear 36 is connected to the output gear 14, and the rotation is transmitted from the output gear 14 to the left and right drive wheels via a differential device (not shown).

Table 1 below summarizes the relationship between the operating states of the friction elements 41 to 46 such as the clutches and brakes and the one-way clutches 51 and 52 and the shift speeds.

[0035]

[Table 1] As is apparent from this table, in the D range, when the 2-4 brake 45 is engaged from the first speed state, the speed is changed to the second speed, and from the third speed state, the 2-4 brake 4 is operated.
When 5 is engaged, the speed is changed to 4th. That is, the second speed and the fourth speed are achieved by engaging the 2-4 brake 45.

Next, the 2-4 brake 4 according to this embodiment
The configuration of No. 5 will be described with reference to FIG.

The 2-4 brake 45 is composed of a brake drum 45a, a brake band 45b wound around the drum 45a, and a hydraulic actuator 60 for applying a tightening force to the band 45b.

The hydraulic actuator 60 comprises three cylinders formed by the transmission case 11, a cover member 61 attached to the case 11, and an insert member 62 inserted in the space formed by these. Have these cylinders from above and the first cylinder 6
3, the second cylinder 64, and the third cylinder 65, which are concentrically arranged, and these cylinders 63 to 6
A stem 66 for applying a tightening force to the band 45b is arranged in the center of the band 5. And this stem 66
The first, second, and third pistons 67, 68, 69 are attached to the
The cylinders 63 to 65 are respectively fitted.

Here, the areas of the first to third pistons 67 to 69 are A1, A2 and A3, respectively, of which the area A2 of the second piston 68 is larger than the areas A1 and A3 of the other pistons 67 and 69. It is narrowed (A1, A3> A
2). Further, a return spring 70 is arranged between the first piston 67 and the transmission case 11. In addition,
In the illustrated embodiment, the first and second pistons 67 and 68 are integrally attached to the stem 66.

The space between the first piston 67 and the transmission case 11 serves as a release chamber 71, and the space between the first piston 67 and the second piston 68 forms a first fastening chamber 72. , Third piston 69 and cover member 61
Is a second fastening chamber 73, and the second fastening chamber 73 is the second fastening chamber 73, and the second fastening chamber 72 is the second fastening chamber 72, and the third gear is the first fastening chamber 72 and the release chamber 71.
In the fourth speed, the line pressure is supplied to each of the first engagement chamber 72, the release chamber 71 and the second engagement chamber 73. Among them, the second and fourth speeds in which the 2-4 brake 45 is engaged. The fastening forces F2 and F4 at
As shown in (2).

[0041]

(Equation 1)

[0042]

(Equation 2) Here, P is the line pressure supplied to each of the chambers 71 to 73, and the spring force of the return spring 70 is sufficiently smaller than the fastening force, and is therefore ignored.

On the other hand, the automatic transmission 10 is provided with a hydraulic control circuit 80 for controlling the hydraulic pressure for selectively engaging each of the friction elements 41 to 46 at each gear according to Table 1. As shown in FIG. 3, the hydraulic control circuit 80 includes a plurality of solenoid valves 81 ... 8 for shifting.
1, a solenoid valve 82 for controlling the lockup clutch 26, a solenoid valve 83 for controlling the line pressure, and the like are provided.

These solenoid valves 81 ...
A control unit 100 for controlling the operations of 81, 82 and 83 is provided, and the unit 100 has a signal from a vehicle speed sensor 101 for detecting the vehicle speed of the vehicle, and a throttle opening sensor for detecting the opening of a throttle valve of the engine. A signal from the turbine 102, a signal from a turbine rotation sensor 103 that detects the output rotation speed (turbine rotation speed) of the torque converter 20, and the like are input, and the solenoid valves 81 ... 81, 82, and 83 are operated based on these signals. When operated, shift control, lockup control, and line pressure control according to the operating state are performed.

Here, the specific construction of the line pressure control portion of the hydraulic control circuit 80 will be described. As shown in FIG. 4, the hydraulic control circuit 80 has a main line from the oil pump 13 for line pressure control. The throttle valve is provided with a regulator valve 91 that adjusts the pressure of the hydraulic oil discharged to the line 90 to a predetermined line pressure, and a throttle modulator valve 92 that supplies control pressure to the regulator valve 91. A constant pressure line 94 led from a reducing valve 93 that reduces the line pressure to a constant pressure is connected to the dulator valve 92.

A pilot line 95 branched from the constant pressure line 94 is connected to a control port 92a at one end of the throttle modulator valve 92, and the pilot line 95 is provided on the pilot line 95 for controlling the line pressure. A duty solenoid valve is installed as the solenoid valve 83, and a pilot pressure corresponding to the duty ratio of the duty solenoid valve 83 is introduced into the control port 92a of the throttle modulator valve 92, so that the constant pressure line 94 is supplied. The supplied constant pressure is adjusted to the control pressure of the pressure according to the duty ratio. And this control pressure is
6 leads to a pressure increasing port 91a provided at one end of the regulator valve 91, whereby the line pressure adjusted by the regulator valve 91 is controlled to a pressure according to the duty ratio.

Next, the learning control operation of the line pressure by the control unit 100 or the hydraulic control circuit 80 will be described. In this embodiment, the learning control is executed during the 1-2 shift and the 3-4 shift of the schedule up, and the learning control at the previous 3-4 shift is performed for the 3-4 shift, which is less frequent. The correction value obtained by the control and the one obtained by converting the correction value obtained by the learning control at the time of the 1-2 shift are used together, but the learning control operation itself is the same as that at the time of the 1-2 shift. The same operation is performed at the time of -4 shift.

That is, this learning control is performed according to the flowchart shown in FIG. 5, and the 1-2 shift command or 3-
When the 4-speed command is output, first in step X1,
Turbine speed change amount before and after gear shift ΔNt (see FIG. 6)
Is the number of revolutions Nt1 at the start of the shift and the gear ratio G before and after the shift.
It is calculated according to the following equation (3) using 1 and G2.

[0049]

(Equation 3) Next, in step X2, a target shift time T'is set based on the map, and in step X3, the target average rotation change is calculated from the target shift time T'and the turbine rotation speed change amount ΔNt according to the following equation (4). The rate dNt 'is calculated.

[0050]

(Equation 4) Further, in accordance with steps X4 to X7, the timer is operated from the start of the gear shift to measure the time T until the end of the gear shift, and in step X8, the actual time is calculated from the time T and the turbine rotation speed change amount ΔNt. Average rotation change rate dN
Calculate t. Then, in step X9, the inertia oil pressure Pi corresponding to the actual average rotation change rate dNt is read from a preset map as shown in FIG.

Here, as shown in FIG. 6, the line pressure is
Torque oil pressure P corresponding to the torque input to the friction element (2-4 brake 45 in this embodiment) during the gear shift
It is set as a value obtained by adding t and the inertia hydraulic pressure Pi corresponding to the speed change of each rotating element due to the gear shift operation, and of these, the inertia hydraulic pressure Pi corresponds to the turbine rotation change rate dNt during the gear shift.

Then, in step X10, the inertia oil pressure Pi corresponding to the actual average rotation change rate dNt read from the map and the average value Pt of the torque oil pressure corresponding to the input torque during the current gear shift during the gear shift operation.
And the target torque oil pressure Pt ′ obtained from the input torque immediately before the start of gear shifting and the target inertia oil pressure Pi ′ corresponding to the above-mentioned target average rotation change rate dNt ′, the learning correction value K is calculated according to the following equation (5). Ask.

[0053]

[Formula 5] Thus, when the learning correction value K is obtained, the line pressure at the time of the next shift is corrected by multiplying the line pressure at that time by the correction value K.

More specifically, this is because the line pressure at the time of the current shift is too high, and therefore the actual rotation change rate dNt
Assuming that the (absolute value) is too large, the corresponding inertia hydraulic pressure Pi becomes larger than the target inertia hydraulic pressure Pi ', and when the actual torque hydraulic pressure Pt is substantially equal to the target torque hydraulic pressure Pt', the learning correction value K is 1 It becomes a smaller value. Therefore, at the next shift, the line pressure becomes lower than that at the previous shift, and the actual rotation change rate dNt or the shift time T
Will approach the target value. On the contrary, if the actual rotation change rate dNt is too small because the line pressure at the time of the current shift is too low, the learning correction value K becomes larger than 1 and At the time of gear shifting, the line pressure becomes higher than that of the previous time, and in this case as well, the actual rotation change rate dNt or the gear shifting time T approaches the target value.

In addition, such learning control is individually performed at the time of the 1-2 shift and the 3-4 shift of the schedule up, and the frequency of the shift is low, and thus the learning opportunity is small. The correction value obtained by the learning control during the 1-2 shift is used after being converted. Next, the conversion control of the correction value will be described with reference to the flowchart of FIG.

In this control, 1-2 shift is performed and 1-
This is executed after the learning correction value K1 for the second shift is obtained. First, in step X11, it is determined whether or not the correction value K1 is 1, and if it is 1, then step X
At 12, the correction value K2 at 3-4 shift is also set to 1. Therefore, when the 3-4 shift is performed thereafter, the line pressure at the shift is held at the previous value.

On the other hand, when the correction value K1 for 1-2 shift obtained by the 1-2 shift this time is not 1, the conversion coefficient α is first calculated in step X13.

This conversion coefficient α is obtained by the equation (1),
It is the ratio of the engaging force F2, F4 of the 2nd speed and the 4th speed shown in (2), and is calculated according to the following equation (6).

[0059]

[Formula 6] Then, in step X14, as shown in the following equation (7),
By multiplying the correction value K1 by the conversion coefficient α,
3-4 Converted to a correction value K2 for shifting.

[0060]

[Formula 7] That is, the correction value K2 for the 3-4 shift is obtained as the product of the correction value K1 for the 1-2 shift and the multiplication factor α of the fastening force F4 at the 4th speed to the fastening force F2 at the 2nd speed. In this case, this magnification (conversion coefficient) α is 2-4 shown in FIG.
It is determined based on the pressure receiving areas A1 to A3 of the pistons 67 to 69 in the actuator 60 of the brake 45.

In this way, the correction value K2 for the 3-4 shift is obtained based on the correction value K1 for the 1-2 shift, so that the same 3-up schedule is used after the 1-2 shift. When four shifts are performed, the correction value K2 based on the correction value K1 set according to the latest state of the automatic transmission or the engine is set even if a considerable amount of time has elapsed since the last 3-4 shift. The line pressure is corrected by using the line pressure. Therefore, the 3-4 shift is performed with the line pressure suitable for the state of the automatic transmission and the engine at that time.

Next, as the hydraulic actuator for the 2-4 brake 45, the actuator 60 in the above-described embodiment is used.
An embodiment will be described in which an actuator having a different configuration from the above is used.

As shown in FIG. 9, the hydraulic actuator 160 according to this embodiment is concentrically provided by the transmission case 111, the cover member 161, and the insert member 162, similarly to the hydraulic actuator 60 according to the above embodiment. 3 cylinders that are connected to each other, and these cylinders are arranged from above in order of the first cylinder 163, the second cylinder 164, and the third cylinder 163.
The first, second, and third pistons 167, 168, 169 are attached to the stem 166 which is the cylinder 165 and which penetrates the central portions of these cylinders 163-165, and these pistons 167-169 are First
~ It is fitted in the 3rd cylinder 163-165, respectively.

Here, the first to third pistons 166 to 16
The areas of 9 are A1 ', A2' and A3 ',
Of these, the area A2 'of the second piston 168 is narrower than the areas A1', A3 'of the other pistons 167, 169 (A1', A3 '>A2'), and the first, second
The point that the pistons 167 and 168 are integrated is the same as in the above embodiment.

Further, the space between the first piston 167 and the transmission case 111 is a release chamber 170, and the space between the first piston 167 and the second piston 168 is the first fastening chamber 171. A space between the third piston 169 and the cover member 161 serves as a second fastening chamber 172, and
The first fastening chamber 171 at the third speed, and the first fastening chamber 171 at the third speed.
And the release chamber 170, the line pressure is supplied to the first fastening chamber 171, the release chamber 170, and the second fastening chamber 172 at the fourth speed, respectively. This point is also the hydraulic actuator 60 according to the embodiment. It is the same.

In the hydraulic actuator 160 according to this embodiment, the first and second pistons 167,1
68 is fitted and fixed to the stem 166 via the sleeve 173, and the third piston 169 is connected to the stem 16
It is fitted to the lower end of 6 so as to be vertically movable relative to the stem 166 within a certain range.

A first return spring 174 is mounted between the first piston 167 and the transmission case 111, and a second return spring 174 is mounted between the second piston 168 and a retainer 175 mounted below the stem 166. Has a second return spring 176 attached.
Then, when the third piston 169 moves relatively upward with respect to the stem 166, the second return spring 176 is retained by the third piston 169.
It is designed to be compressed via 75.

According to this hydraulic actuator 160,
The line pressure P2 is supplied to the first fastening chamber 171 at the 2nd speed, and 3
At high speed, the line pressure P is applied to the first fastening chamber 171 and the release chamber 170.
2 and P3 are respectively supplied, and in the fourth speed, the line pressures P2, P3 and P4 are respectively supplied to the first engagement chamber 171, the release chamber 170 and the second engagement chamber 172. Force (engagement force of the 2-4 brake 45 in the 2nd and 4th speeds) F2 ', F3', F
4'is given by the following equations (8), (9), (10), respectively.

[0069]

(Equation 8)

[0070]

[Formula 9]

[0071]

[Formula 10] Here, S1 is the spring force of the first return spring 174 in the length (compressed state) when the first and second pistons 167 and 168 are in the engagement position of the 2-4 brake 45, and S1 ′ is , Similarly the first and second pistons 167, 16
8 is the spring force of the first return spring 174 at the length when 8 is in the release position of the 2-4 brake 45. Further, in S2, the third piston 169 is the 2-4 brake 45.
It is the spring force of the second return spring 176 in the length (compressed state) when it is in the fastening position.

Also in the embodiment using the hydraulic actuator 160, as in the case of the above-described embodiment, at the time of the 1-2 shift and the 3-4 shift of the schedule up, as shown in FIG.
The learning control of the line pressure shown in the flowchart is performed, and when the frequency is low at 3-4 shift, the correction value obtained by the learning control at the previous 3-4 shift and 1-2
It is designed to be used together with the one obtained by converting the correction value obtained by the learning control at the time of shifting, and in that case, the correction value K1 obtained at the time of 1-2 shifting is converted into the correction value K2 for 3-4 shifting. The control to be performed is performed in the same manner as in the above embodiment according to the flowchart shown in FIG.

In this case, in this embodiment, the conversion coefficient α obtained in step X13 of the flowchart of FIG.
Is 2− in the second speed and the fourth speed shown in the formulas (8) and (10).
As a ratio of the fastening forces F2 'and F4' of the four brakes, it is obtained according to the following equation (11).

[0074]

[Formula 11] Then, thereafter, by performing the same processing as in the above-mentioned embodiment, the schedule-up 3-
During four gear shifts, the gear shift is performed at a line pressure that is well suited to the current state of the automatic transmission and the engine, although the frequency is low.

In the above embodiment, the learning control is performed during the 1-2 shift and the 3-4 shift, and the learning correction value obtained during the 1-2 shift is converted during the infrequent 3-4 shift. However, the learning correction value at the time of 1-2 shift may always be converted and used without performing learning control at the time of 3-4 shift.
The learning control is performed at the time of shifting and at the time of shifting at 3-4, and at any shifting, the learning correction value obtained at the time of shifting,
You may make it use together with what changed the learning correction value calculated | required at the time of the other gear shift. In this case, the conversion coefficient for converting the correction value K2 obtained during the 3-4 shift to the correction value K1 for the 1-2 shift is the correction coefficient α shown in the equation (6) or (11) in the above embodiment. It is the reciprocal.

Further, although the present invention is applied to the 2-4 brake in the above embodiments, other friction elements such as other brakes or clutches that are engaged at different gears like the 2-4 brake are used. If present, the invention is likewise applicable for that friction element.

[0077]

As described above, according to the present invention, in the automatic transmission which is achieved by engaging the same friction element in the first gear and the second gear, the first gear A learning correction value for the engaging force of the friction element is determined when the gear is shifted to the next gear, and the correction value is used to correct the engaging force of the friction element at the time of shifting to the first gear after the next time. Since this correction value is converted so that it is also used when shifting to the second shift stage, even if the shift to the second shift stage is infrequent, the first shift stage immediately before the shift is performed. The engaging force of the frictional element is corrected based on the correction value determined during the gear shift to, so that the automatic gearbox and the engine state at that time are corrected, and the gearshift is performed well. It will be.

Further, the fastening force at the time of shifting to the first shift stage and at the time of shifting to the second shift stage can be corrected only by determining the learning value at the shift to the first shift stage. This simplifies the control and saves the amount of memory used for storing the correction value.

According to the second aspect of the invention, the learning correction is performed also during the shift to the second shift stage, and the correction value determined when shifting to the second shift stage and the first shift are performed. The correction value determined and converted at the time of shifting to the gear is used together, so that the correction of the fastening force at the time of shifting to the second gear can be performed more accurately.

Further, according to the third aspect of the present invention, the correction values are determined at the time of shifting to the first and second shift speeds, and these correction values are mutually converted to shift to the other shift speed. Since it is used at the time of shifting to any shift stage, the correction value determined at the time of shifting to that shift stage and the correction value determined and converted at the time of shifting to the other shift stage are used together. Therefore, during both shifts,
The control accuracy of the fastening force is further improved.

According to the fourth aspect of the invention, when the friction element to be engaged at the first and second gears has two engaging hydraulic chambers, the correction value is based on the pressure receiving area of these hydraulic chambers. Therefore, in any of the above-described first to third inventions, the correction value conversion can be accurately performed by a simple calculation.

Further, according to the fifth aspect of the invention, each of the above aspects of the invention is applied to the 2-4 brakes which are engaged in the second speed and the fourth speed. Even though the frequency is low, the fastening force can be controlled with high accuracy.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts of a 2-4 brake in the same automatic transmission.

FIG. 3 is a control system of the same automatic transmission.

FIG. 4 is a circuit diagram of a main part of a hydraulic control circuit in the automatic transmission.

FIG. 5 is a flowchart showing an operation of learning control of the line pressure.

FIG. 6 is a time chart of the same control operation.

FIG. 7 is an explanatory diagram of a map used in the control.

FIG. 8 is a flowchart showing an operation of correction value conversion control.

FIG. 9 is a cross-sectional view of essential parts of a 2-4 brake according to another embodiment of the present invention.

[Explanation of symbols]

45 friction element (2-4 brake) 72, 73, 171, 172 fastening hydraulic chamber (first,
Second fastening chamber) 83,91 Correction means (regulator valve, duty solenoid valve) 100 Actual shift time detection means,
Correction value determination means, correction value conversion means (control unit)

Claims (5)

[Claims] 1. An automatic transmission that is achieved by engaging the same friction element between a first speed change step and a second speed change step, wherein an actual speed change time when the speed is changed to the first speed change step is described. An actual shift time detecting means for detecting, and a correction value deciding means for determining a correction value of the engaging force of the friction element at the time of shifting to the first shift stage from the next time on the basis of the actual shift time and the target shift time. First correction means for correcting the engagement force of the friction element at the time of shifting to the first gear according to the determined correction value, and the engagement force at the first gear and the second gear Correction value conversion means for converting the above correction value into a correction value for the engagement force at the time of shifting to the second gear, and to the second gear using the converted correction value. Second correction means for correcting the engagement force of the friction element at the time of gear shifting A control device for an automatic transmission, characterized in that 2. An automatic transmission that is achieved by engaging the same friction element between the first speed change step and the second speed change step, wherein an actual speed change time when the speed change is performed to the first speed change step is performed. First actual shift time detecting means for detecting, and first determining the correction value of the engagement force of the friction element at the time of shifting to the first shift stage after the next based on the actual shift time and the target shift time. Correction value determining means, first correction means for correcting the engaging force of the friction element at the time of shifting to the first shift speed according to the determined correction value, and shifting to the second shift speed. Second actual shift time detecting means for detecting the actual shift time at this time, and correction of the engagement force of the friction element at the time of shifting to the second shift stage after the next time based on the actual shift time and the target shift time. Second correction value determining means for determining the value, and the engagement force at the first speed Correction value conversion means for converting the correction value determined by the first correction value determination means from the relationship with the engagement force at the second gear to the correction value for the engagement force at the time of shifting to the second gear. And a correction value determined by the second correction value determination means and a correction value converted by the correction value conversion means are used to correct the engagement force of the friction element at the time of shifting to the second gear. 2. A control device for an automatic transmission, comprising: 3. In an automatic transmission that is achieved by engaging the same friction element between the first gear and the second gear, the actual gear shift time when shifting to the first gear is First actual shift time detecting means for detecting, and first determining the correction value of the engagement force of the friction element at the time of shifting to the first shift stage after the next based on the actual shift time and the target shift time. Correction value determining means, second actual shift time detecting means for detecting the actual shift time when the gear is shifted to the second shift stage, and the next and subsequent ones based on the actual shift time and the target shift time. A second correction value determining means for determining a correction value for the fastening force of the friction element during the shift to the second shift stage; and a fastening force at the first shift stage and a fastening force at the second shift stage. From the relationship, the first correction value determined by the second correction value determining means is set to the first correction value.
From the relationship between the first correction value conversion means for converting the correction value of the fastening force at the time of shifting to the shift speed and the relationship between the fastening force at the first shift speed and the fastening force at the second shift speed, Second correction value conversion means for converting the correction value determined by the first correction value determination means into a correction value for the fastening force during shifting to the second gear, and the first correction value determination means. First correction means for correcting the engagement force of the friction element at the time of shifting to the first speed using the determined correction value and the correction value converted by the first correction value conversion means; The correction value determined by the second correction value determination means and the correction value converted by the second correction value conversion means are used to correct the engagement force of the friction element at the time of shifting to the second gear. A control device for an automatic transmission, comprising: a second correction means. 4. The friction element has two engagement hydraulic chambers, and a correction value conversion for converting a correction value from the relationship between the engagement force at the first gear and the engagement force at the second gear. The means is
The control device for an automatic transmission according to any one of claims 1 to 3, wherein the correction value is converted based on the pressure receiving areas of the two fastening hydraulic chambers of the friction element. 5. The friction element is a 2-4 brake having, as an engagement hydraulic chamber, a hydraulic chamber to which hydraulic pressure is supplied at the second speed and a hydraulic chamber to which hydraulic pressure is supplied at the fourth speed. The control device for the automatic transmission according to claim 4.