JP3531513B2 - Control device for automatic transmission for vehicles - Google Patents

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 for a vehicle, which automatically shifts a shift stage of the automatic transmission for a vehicle, and more particularly to a hydraulic friction engagement which is involved in the shift during a shift period. The present invention relates to a technique for suppressing shift transient pressure of a device.

[0002]

2. Description of the Related Art In an automatic transmission for a vehicle in which a gear selected from a plurality of gears is established by a combination of operations of a plurality of hydraulic friction engagement devices, a gear shift is made based on a gear shift state at the time of gear shift. It has been practiced to change the speed change transient oil pressure of the involved hydraulic friction engagement device by learning control to improve the speed change feeling. For example, JP-A-8
That is the shift control device described in Japanese Patent Publication No. 285064. According to this, the tie-up that occurs during the clutch-to-clutch shift period, which is a temporary decrease in the output shaft torque of the automatic transmission, and the engine blow (overshoot in which the input shaft rotation speed of the automatic transmission temporarily increases). ) To prevent the shift feeling from being impaired,
The engagement pressure of the hydraulic friction engagement device involved in the clutch-to-clutch shift is corrected by learning control.

In the above automatic transmission, generally, a line pressure adjusted to a magnitude corresponding to an input shaft torque input to the automatic transmission is generated, and the line pressure is generated in the hydraulic friction engagement device. By being used as the source pressure, for example, slippage of the hydraulic friction engagement device engaged during the gear shift period is prevented.
Therefore, in order to control the engagement pressure of the hydraulic friction engagement device within the gear shift period, that is, the gear shift transient pressure, the back pressure control valve that independently controls the back pressure is not used, and the line pressure is set to the hydraulic pressure. It is conceivable that the line pressure is used as a back pressure of an accumulator connected to the frictional engagement device so that the line pressure is corrected by learning control in order to obtain a shift feeling within a shift period.

[0004]

However, in the above-described control device for an automatic transmission for a vehicle, when a change in the accelerator pedal operation amount or a change in the engine rotation speed occurs during the shift period, it is involved in the shift. Since the back pressure of the accumulator connected to the hydraulic friction engagement device is also changed and the shift state of the automatic transmission is affected, the shift shock is suppressed even if the learning control is performed based on the shift state. In addition, there is a drawback that the shift feeling may not be obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to be used as a back pressure of an accumulator connected to a hydraulic friction engagement device in which line pressure is involved in gear shifting. Even so, it is an object of the present invention to provide a control device for an automatic transmission for a vehicle that can obtain a good learning control effect.

[0006]

[Means for Solving the Problems]
The gist of the present invention is to provide a plurality of hydraulic friction members.
The gear stage is selected by the combination of the operation of the gearbox
In an automatic transmission for a vehicle, the source of the hydraulic friction engagement device
When the shift transient hydraulic pressure is controlled using the line pressure that is the pressure
At the same time, the line pressure within the shift period is learned based on the shift state.
A control device of a manual control type, comprising:
A shift start point determining means for determining the start point, and (b) the shift opening
When the start point of the shift is determined by the start point determination means
The line pressure at that time during the shifting period after that.
And line pressure holding means, (c) After the shift start point
After that, the input shaft rotation speed of the automatic transmission is
Rotation synchronization determination means for determining whether or not the rotation speed is synchronized
When, (d) By the rotation synchronization determination means, the automatic transmission
It is determined that the input shaft rotation speed is synchronized with the rotation speed after shifting.
If the line pressure is retained, it is retained by the line pressure retaining means.
Determined from the line pressure based on the input torque of the automatic transmission
Line pressure switching means for switching to a fixed line pressure,
(e) Line switched by the line pressure switching means
Pressure so that it does not fall below the line pressure used when determining the shift start
Line pressure limiting means to limit toIs included.

[0007]

In this way, when the shift start point determination means determines the shift start point, the line pressure holding means determines the line pressure at the shift start point in the subsequent shift period. Since it is held, the line pressure at the time of the shift start determination thereafter is used as the back pressure of the accumulator connected to the hydraulic friction engagement device involved in the shift. Therefore, even if there is a change in the accelerator pedal operation amount or a change in the engine speed during the shift period, the back pressure of the accumulator is not affected, and the learning condition is stabilized and good learning control is achieved. The effect is obtained. Also, the rotation synchronization judgment hand
The input shaft rotation speed of the automatic transmission changes depending on the gear
Line pressure switching means
The line held by the line pressure holding means
Determined from the pressure based on the input torque of the automatic transmission
Input line of automatic transmission
After it is determined that the rotation speed is synchronized with the rotation speed after shifting
Of the hydraulic friction engagement device occurs during the period
Is preferably prevented. Also, the input shaft rotation of the automatic transmission
Line pressure switching after the rotation speed is synchronized with the rotation speed after shifting
The line pressure that can be switched by the means is
Do not fall below the line pressure when determining the start of gear shift depending on the gear
The hydraulic friction engagement device slips because it is limited to
Is preferably prevented.

[0008]

Another aspect of the present invention is preferably an engine load change determining means for determining whether or not there is a change in engine load within a shift period after the shift start point, and the engine load change determining means. A line pressure holding releasing means for releasing the holding of the line pressure by the line pressure holding means when it is determined that the engine load has changed is further included. With this configuration, when the engine load changes, the line pressure holding release means releases the line pressure holding by the line pressure holding means, which causes a sudden increase in the input torque of the automatic transmission during the shift period. As a result, slippage of the hydraulic friction engagement device is preferably prevented.

[0009]

[0010]

[0011]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a torque converter 12 connected to an engine 10 of a vehicle, an automatic transmission 14, a differential gear unit 16, and a hydraulic control device or a hydraulic control circuit 18 for controlling the shift stages of the automatic transmission 14. , Its hydraulic control circuit 1
The electronic shift control device 20 for controlling the transmission No. 8 is shown. The power output from the engine 10 is transmitted to drive wheels (not shown) via the torque converter 12, the automatic transmission 14, the differential gear device 16, the left and right axles 22 and 24, and the like.

The torque converter 12 has a pump impeller 28 connected to a crankshaft 26 of the engine 10.
A turbine impeller 32, which is connected to the input shaft 30 of the automatic transmission 14 and to which power is transmitted from the pump impeller 28 via fluid, and is fixed to a position-fixed housing 36 via a one-way clutch 34. The fixed impeller 38 and the lock-up clutch 40 that directly connects the pump impeller 28 and the turbine impeller 32 via a damper (not shown) are provided.

The automatic transmission 14 has four forward speeds and one reverse speed.
It is a multi-stage transmission that achieves a high speed gear stage, including the input shaft 30, a set of Ravigneaux type planetary gear set 44, a ring gear 48 that rotates together with a ring gear 46 of the Ravigneaux type planetary gear set 44, and an engine 10. The driving force from the ring gear 4 to the differential gear device 16 or its output.
8 and the differential gear device 16 are provided with a counter shaft 50 that functions as an output shaft that transmits power.

In the Ravigneaux type planetary gear set 44, a single pinion planetary gear set 52 and a double pinion planetary gear set 54 share a carrier 56 and the ring gear 46. The single pinion planetary gear device 52 is composed of a sun gear 58, a planetary gear 60 attached to the carrier 56, and the ring gear 46. The double pinion planetary gear 54 includes a sun gear 62, a first pinion gear 64 and a second pinion gear 66 that are integrally coupled to each other and rotatably attached to the carrier 56.

Some of the constituent elements of the single pinion planetary gear unit 52 and the double pinion planetary gear unit 54 are not only integrally connected to each other, but also selectively connected to each other by three clutches C1, C2 and C3. It is supposed to be done. Further, some of the constituent elements of the single pinion planetary gear device 52 and the double pinion planetary gear device 54 are three brakes B1, B2.
Selectively coupled to the housing 36 by B3,
Further, some of those components are engaged with the housing 36 by the two one-way clutches F1 and F2 in the rotational direction thereof. The portions of the torque converter 12 and the automatic transmission 14 other than the counter shaft 50 are arranged symmetrically with respect to the shaft center of the input shaft 30 and the like. The lower side is omitted.

The clutch C, which is a hydraulic friction engagement device.
1, C2, C3 and brakes B1, B2, B3 are composed of, for example, a multi-plate clutch, a band brake having one band or two bands with opposite winding directions, and the like By controlling the frictional engagement and disengagement of each of them by the hydraulic control circuit 18 which operates according to the command from the gearbox 20, as shown in FIG. 2, the gear ratio γ (= rotation speed of the input shaft 30 / counter It is possible to obtain four forward gears and one reverse gear having different rotational speeds of the shaft 50. “1ST”, “2ND”, “3RD”,
"4TH" represents the first speed gear, the second speed gear, the third speed gear, and the fourth speed gear on the forward side, respectively, and the gear ratio γ is from the first speed gear to the fourth speed. It gradually becomes smaller toward the higher gear. Further, in FIG. 2, “P”,
“R”, “N”, “D”, “2”, and “L” are alternatively selected by the manual operation of the shift lever 84. The parking (P) range, reverse (R) range, and neutral (N). ) Range, drive (D) range, second (2)
A range and a low (L) range are shown respectively. The P range and the N range are non-running ranges selected when the vehicle is not running, and include the R range, the D range, and the 2 range.
The range and the L range are traveling ranges for moving the vehicle backward or forward. In addition, 2 range, L range,
It is also an engine braking range because it not only increases the driving force of the vehicle but also generates engine braking.

Further, in FIG. 2, the mark ◯ indicates the engaged or activated state, and the mark x indicates the released or non-actuated state. The shift between the third speed and the fourth speed is performed by a pair of hydraulic friction engagement devices (clutch C) involved in the speed change.
1 and the brake B1) is achieved by releasing one of the two and engaging the other, so it is called a clutch-to-clutch shift.

The hydraulic control circuit 18 corresponds to three solenoid valves SV1 to SV3 used for controlling the gear stages of the automatic transmission 14 and the throttle opening TA detected by a throttle opening sensor 76 described later. A linear solenoid valve SLT that generates a control hydraulic pressure P _S of a predetermined magnitude, for example, a linear solenoid valve that generates a hydraulic pressure for controlling the frictional engagement of the lock-up clutch 40, the release of the frictional engagement, and the slip amount thereof. The SLU and an oil temperature sensor 88 that functions as a hydraulic oil temperature detection device that detects the oil temperature T _OIL of the hydraulic oil in the hydraulic control circuit 18 are provided.

The shift electronic control unit 20 includes a CPU 7
0, a RAM 72, a ROM 74, a so-called microcomputer including an input / output interface (not shown), and the like, in which a throttle opening sensor 76 for detecting an opening TA of a throttle valve provided in an intake pipe (not shown) of the engine 10 is provided. , An engine speed sensor 78 for detecting the speed N _E of the engine 10, an input shaft speed sensor 80 for detecting the speed N _T of the turbine impeller 32, that is, a speed N _IN of the input shaft 30, the counter shaft The vehicle speed sensor 82 for detecting the rotational speed N _{C of} 50, that is, the vehicle speed V, the operating position of the shift lever 84, that is, L, S,
A signal indicating the throttle opening TA from an operation position sensor 86 that detects any one of the D, N, R, and P ranges and an oil temperature sensor 88 that detects the temperature of the hydraulic oil in the hydraulic control circuit 18.
A signal representing the engine speed N _E (rpm), a signal representing the input shaft speed N _IN (rpm), a signal representing the output shaft speed N _C (rpm), that is, a vehicle speed V, and an operation position P _ST of the shift lever 84. Signal indicating, hydraulic oil temperature T in hydraulic control circuit 18
A signal representative of _OIL is provided. The CPU 70 of the electronic shift control device 20 processes the input signal while using the RAM 72 in accordance with a program stored in the ROM 74 in advance, and based on the processing result, for example, detects the running state of the vehicle and the electromagnetic opening / closing valve. SV1 to SV
3. Control the linear solenoid valve SLT and SLU.

FIG. 3 is a diagram for schematically explaining the structure of the main part of the hydraulic control circuit 18. In FIG. 3, the source pressure generator 90 adjusts the line hydraulic pressure P _{L obtained} by adjusting the pressure of the hydraulic oil pumped from the hydraulic pump 92 rotationally driven by the engine 10 to a value according to the engine load. The frictional engagement devices C1, C2, C3, B1, B2, B3 are output to the shift valve device 94 and the like as the original pressure. Manual valve 9
6 is mechanically connected to the shift lever 84, and responds to a travel range selection operation of the shift lever 84 to switch the line hydraulic pressure P _L to correspond to the selected travel range. Hydraulic pressure, eg R
The range pressure, the D range pressure, the 2 range pressure, and the L range pressure are output to the shift valve device 94. Further, the electromagnetic on-off valves SV1 and SV2 output the signal pressure to the shift valve device 94 by being operated by the electronic control device 20 for shifting exclusively for selecting the gear stage.

The shift valve device 94 includes a manual valve 96.
Oil pressure and two first electromagnetic opening / closing corresponding to the driving range from
The hydraulic signals from the valve SV1 and the second solenoid on-off valve SV2
1-2 shifts that are switched during gear shifting based on
Valve, 2-3 shift valve, 3-4 shift valve, etc.
According to the operation shown in FIG. 2, each hydraulic friction engagement device C
Selective engagement hydraulic pressure to 1, C2, C3, B1, B2, B3
Supply to. Those hydraulic friction engagement devices C1, C2, C
Clutches C1, C2, C among 3, B1, B2, B3
3 and the brakes B1 and B2 are
That is, C1 accumulator for reducing the increase in engagement torque
Lator A_C1, C2 accumulator A_C2, C3 Accumulation
Data A_C3, B1 accumulator A_B1, B2 Accumley
Type A_B2Are connected respectively. C1 Accumulation above
Data A_C1And B1 accumulator A _B1And the above C2
Cumulator A_C2, C3 accumulator A_C3, And B
2 Accumulator A_B2And the electronic control unit 20 for shifting.
Line oil pressure P that can be changed by a command from_LBut that
It is supplied as accum back pressure respectively, and shift transition
Adjust the engagement hydraulic pressure of each hydraulic friction engagement device within the period
The gear shift transient control is performed.

The shift valve device 94 and the clutch C are used.
1 and C1 accumulator A_C1Between the third electromagnetic
Hydraulic signal from on-off valve SV3 and engagement of brake B1
Pressure P _B1Switch the flow resistance between them based on
The engagement timing of the clutch C1 depends on the vehicle state.
Orifice for adjusting triggering or release timing
With multiple oil passages and oil that switches between these multiple oil passages
An orifice switching valve device 98 having a path switching valve is provided.
Has been. Engagement pressure P of brake B1_B1Orifice cut
By acting on the valve conversion device 98, the clutch C
Engaging pressure P of 1_C1The rising and falling edges of
Engagement pressure P of rake B1_B1On the fall and rise of
It is controlled in relation. For example, 4 →
In 3 downshift, the release side brakes B1 and B1
Cumulator A_B1The hydraulic oil in the
Engaging pressure P_B1The orifice switching valve device 98
The flow resistance to the clutch C1 is reduced and it operates quickly.
Oil is supplied, but if it falls below a specified value, its flow resistance will increase.
The engagement pressure P of the clutch C1 is increased._C1Slowly rises
It is supposed to be done.

FIG. 4 illustrates in detail the line pressure generator 90 of the hydraulic control circuit 18 for generating the line hydraulic pressure P _L which is the original pressure of the hydraulic oil supplied to the clutch C1 and the brake B1. It is a figure. In FIG.
The hydraulic pump 92, which is rotationally driven by the engine 10, sucks the recirculated hydraulic oil through the strainer 100 to send the hydraulic oil to the line pressure regulating valve 102 under pressure.

The line pressure regulating valve 102 is composed of the plunger 11
0 and the axial direction of the plunger 110 in contact with the plunger 110
The input port b and the output port d are movably provided
Spool valve 112 for opening and closing the space, and the spool valve
112 for biasing the valve 112 in the valve closing direction via the spring receiving plate 114.
And a pulling 116, and is provided to its input port b.
The hydraulic pressure of the hydraulic oil supplied from the hydraulic pump 92 is
Supplied from the near solenoid valve SLT to the input port a
Control oil pressure P_SBased on the
The automatic transmission 14 has a size corresponding to the input torque.
In hydraulic pressure P_LRegulate to. Of the line pressure regulating valve 102
The hydraulic pressure of the input port b is fed to the input port c.
It is supplied as back hydraulic pressure. The spring 11
6 urging force W_REG, The land of the spool valve 112
Area of the annular pressure receiving surface of 118 is A _REG1, Above spool valve
Plunge for urging the child 112 toward the valve closing direction of the output port d
Area of the pressure receiving surface of_REG2If so, the above line
Hydraulic pressure P_LIs expressed by the following equation (1). Here, formula (1)
Is the above line hydraulic pressure P_LIs the control hydraulic pressure P_SIn proportion to
It can be generated. Control oil pressure P_SIs en
Jin load or input torque T of the automatic transmission 14_INLarge of
In the normal case where the line pressure is indicated, the above line hydraulic pressure P _LIs oil
Necessary within the range where slippage of the pressure frictional engagement device does not occur and
Engine load or automatic transmission that provides sufficient value
14 input torque T_INIt corresponds to the size of
The pressure is adjusted to the normal pressure adjustment value.

[0026]

[ _Equation 1] P _L = (A _REG2 / A _REG1 ) · P _S + W _REG / A _REG1 (1)

The linear solenoid valve SLT includes a spool valve element 120 that opens and closes between the input port a and the output port b, and a spring 122 that biases the spool valve element 120 in the valve opening direction. . The aforementioned input port a, a constant pressure P _SOL is supplied, the control as a hydraulic whose constant pressure P _SOL is pressure regulated in response to the exciting current output from the shift electronic control unit 20 to the linear solenoid S _SLT The hydraulic pressure P _S is generated at the output port b. The biasing force that biases the spool valve 120 in the valve closing direction of the output port b in accordance with the exciting current of the linear solenoid S _SLT is F _I , the biasing force of the spring 122 is W _SLT , and the spool valve 120 _Assuming that the area of the annular pressure receiving surface of the land 124 is A _SLT , the oil chamber 128 between the land 124 and the land 126 and the output port b are communicated with each other by the oil passage 130.
Since the hydraulic pressure acting on the annular pressure receiving surface of the control hydraulic pressure is the control hydraulic pressure P _S , the control hydraulic pressure P _S is expressed by the formula (2) or FIG.
It is represented by the characteristic diagram of.

[0028]

[Equation 2] P _S = W _SLT / A _SLT −F _I / A _SLT (2)

In FIG. 4, the pressure reducing valve 132 is a spool valve 13 that opens and closes between the input port a and the output port b.
6 and a spring 138 for urging the spool valve element 136 in the valve opening direction, the line hydraulic pressure P _L supplied to the input port a thereof is adjusted to the constant pressure P _SOL , and the output port b thereof is adjusted. And supplies it to the linear solenoid valve SLT, the linear solenoid valve SLU, and the like. The hydraulic pressure of the output port b is supplied to the input port c of the pressure reducing valve 132 as a feedback hydraulic pressure. If the pressure receiving area of the spool valve element 136 communicating with the input port c is A _MOD and the urging force of the spring 138 is W _MOD , the constant pressure P _SOL is a constant pressure expressed by the equation (3). Become.

[0030]

[ _Formula 3] P _SOL = W _MOD / A _MOD (3)

FIG. 5 is a functional block diagram for explaining the main part of the control function of the shift electronic control unit 20. Figure 5
In the above, the shift control means 140 causes the vehicle speed V and the throttle opening TA, the fuel injection amount F, and the intake air obtained from the vehicle speed sensor 82 from the shift map previously selected in response to the operation of selecting the travel range of the shift lever 84. A shift point control for determining a shift of the automatic transmission 14 and outputting a shift command based on an engine load represented by any one of an air amount Q and an accelerator pedal operation amount, and a shift period of the automatic transmission 14 In step 1, the degree of shift is determined based on the vehicle speed V, and shift transient control is executed to transiently control the engagement hydraulic pressure of the hydraulic friction engagement device involved in the shift to improve the shift feeling.

That is, in the shift point control, the point representing the actual vehicle speed V and the engine load is the shift line on the two-dimensional coordinate formed by the vehicle speed axis representing the actual vehicle speed V and the engine load axis representing the engine load. A shift determination is made based on which of the gear stages the vehicle crosses across and is divided by the shift line. For example, when the points representing the actual vehicle speed V and the engine load cross the low-speed side of the 4 → 3 downshift line, for example, the 4 → 3 downshift is determined. Further, in the above-mentioned shift transient control, for example, in order to smoothly execute the release of the brake B1 and the engagement of the clutch C1 involved in the 4 → 3 downshift within the 4 → 3 downshift period, for example, in FIG. As shown, a hydraulic pressure is basically formed to decrease the engagement pressure P _{B1 of the} brake B1 and simultaneously increase the engagement pressure P _{C1 of the} clutch C1 in accordance with the degree of progress of the shift. Then, the actual input shaft rotation speed N _IN
Predetermined in the case but the input shaft rotational speed after the third-speed position established (G ₃ × N _O However, G ₃ is the gear ratio of the third speed gear step) it determines whether synchronization with, is determined Clutch C1 after time
The engagement hydraulic pressure P _C1 is set to the maximum value (= P _L ) and the 4 → 3 downshift control is terminated.

The line pressure control means 142 is, for example, as shown in FIG.
Driven on the basis of the actual input shaft torque T _IN, that is, the turbine torque T _T from a relationship stored in advance so as not to cause slippage in another hydraulic friction engagement device that is engaged during gear shifting as shown in FIG. The signal D _{SL T} is determined and output, and the line pressure P _L as shown in FIG.
02 to output from the linear solenoid valve SL
Drive T. Further, the line pressure control means 142, during the shift period, performs the learning control means 14 for shift transient control.
4 or the line pressure P _L is changed based on a command from the line pressure holding means 148, and the engagement pressure of the hydraulic friction engagement device involved in the gear shift, for example, the engagement pressure P _{B1 of the} brake B1 in the 4 → 3 downshift. And the engagement pressure P _{C1 of the} clutch C1 is controlled.

The learning control means 144 is, for example, a clutch.
Within the 4 → 3 downshift period, which is a two clutch shift
If the brake B1 is released too early,
Input shaft rotation speed due to engagement of C1 being too slow.
N_INIs the rotation speed (G ₃× N_CHowever, G₃Is the third speed
Overshoot that temporarily exceeds the gear ratio).
Engine blowout or release of brake B1
Too late or clutch C1 engaged too early
Due to this, the output shaft torque of the automatic transmission 14 temporarily decreases.
The tie-up that occurs
Or the tie-up should be below the preset target value
Then, the line pressure P within the next 4 → 3 downshift period_LSupplement
To correct. As described above, the line pressure P_LIs the brake B1
B1 accumulator A connected to_B1, And clutch
C1 accumulator A connected to C1_C1As back pressure
Since it is operated, for example
If it occurs, the line pressure P within the 4 → 3 downshift period
_LIs corrected to the rising side by learning, and tie-up occurs
In case of 4 → 3 downshift period, the line pressure P_LLearning
It is designed to be corrected to the descending side.

The shift start point determining means 146 starts to increase the input shaft rotation speed N _IN of the automatic transmission 14 shown at time t ₂ in the 4 → 3 down shift period, which is a clutch-to-clutch shift, for example. The substantial shift starting point, that is, the start point of the inertia phase (the section in which the rotational speed change of the rotating member of the automatic transmission 14 for speed change occurs) is the change rate of the input shaft rotational speed N _IN . Alternatively, the determination is made based on the rate of change of the output shaft rotation speed N _C. When the shift start point determining means 146 determines the shift start point within the 4 → 3 down shift period, the line pressure holding means 148 determines the line pressure P _{Li at} that time, that is, the line pressure P _Li . Linear solenoid valve to generate SL
The drive signal D _{SLTi of} T is stored, and the line pressure control means 142
To hold the drive signal D _SLTi and maintain a constant line pressure P _Li.
Is continuously generated.

The engine load change determining means 150 determines whether or not there is an engine load change that causes a rapid increase in the input torque T _IN of the automatic transmission 14 within the 4 → 3 downshift period, and determines whether the throttle opening TA is reached. The determination is made based on, for example, that the change rate DTA of D exceeds the preset determination reference value α. This judgment reference value α is a 4 → 3 downshift when the back pressure of the B1 accumulator A _B1 and the C1 accumulator A _{C1 or} the line pressure is held at the value P _Li at the time of the shift start determination by the line pressure holding means 148. It is a value that has been experimentally obtained in advance in order to determine the state in which the brake B1 and the clutch C1 involved in the slipping occur. The line pressure holding releasing means 152 holds the driving signal D _SLTi by the line pressure holding means 148, that is, holds the line pressure P _{Li while} the engine load change judging means 150 judges that there is an engine load change. The pressure is released and the line pressure holding means 148 returns to the state before the line pressure is held.

The rotation synchronization determining means 154 determines that the input shaft rotational speed N _IN of the automatic transmission 14 is the rotational speed after the speed change (G ₃ × N _C) within the 4 → 3 downshift period, which is the clutch-to-clutch shift. However, G ₃ determines the establishment of the third speed gear, that is, the rotation synchronization based on the fact that the gear ratio of the third speed gear has been reached. The time point t _{3 in} FIG. 6 indicates the time point when the rotation is synchronized. When the rotation synchronization determining means 154 determines the rotation synchronization, the line pressure switching means 156 determines the input torque T _{IN of the} automatic transmission 14 from the line pressure P _Li held by the line pressure holding means 148, for example. The line pressure P _L is determined based on The line pressure limiting means 158 is the rotation synchronization determining means 15
The line pressure P _L switched by the line pressure switching means 156 after the rotation synchronization is determined by
The lower limit value is limited so that the line pressure P _Li at the time of determining the shift start is not lowered.

The essential parts of the control operation of the electronic shift control device 20 will be described below with reference to FIGS. 10 and 11. Figure 10
Shows a line pressure control routine during shifting, and FIG. 11 shows a line pressure limit control routine.

At SA1 in FIG. 10, it is determined whether or not a power-on 4 → 3 downshift, which is a clutch-to-clutch shift, has been output. When the determination of SA1 is negative, this routine is ended, but when the determination is affirmative, it is determined in SA2 corresponding to the shift start point determination means 146 whether or not the inertia phase has started. This state is shown at time t _{1 in} FIG. Since the determination of SA2 is initially denied, in SA3 corresponding to the line pressure control means 142, the line pressure control corresponding to the input torque T _IN of the automatic transmission 14, that is, the B1 accumulator A _B1 and the C1 accumulator A _C1 . After the back pressure control is started, SA2 and below are executed again.

While the above steps are repeatedly executed, when the time point t ₃ in FIG. 6 is reached, the determination at SA2 is affirmative, so the SA corresponding to the line pressure holding means 148 is determined.
In 4, the line pressure at the start of the inertia phase, that is, the back pressure value P _Li is determined and held. As a result, the line pressure, that is, the back pressure value is maintained at a constant value P _Li until the rotation synchronization is determined.

Next, the engine load change judging means 1
At SA5 corresponding to 50, whether or not an engine load change that causes a rapid increase in the input torque T _IN of the automatic transmission 14 has occurred is determined by, for example, a rate of change DTA of the throttle opening TA set in advance. It is determined based on whether the value is equal to or less than α. Normally, this determination at SA5 is affirmative, so at SA6 corresponding to the rotation synchronization determination means 154, the input shaft rotation speed N _IN of the automatic transmission 14 is the rotation speed after the shift (G ₃ × N _C, but G ₃ Indicates whether or not the gear ratio of the third gear is reached, that is, whether or not the rotation is synchronized. Initially, the determination of SA6 is denied, so SA5 and the subsequent steps are repeatedly executed.

While the above steps are repeatedly executed, when the input shaft rotation speed N _IN reaches the rotation speed after shifting, that is, the rotation speed of the third gear, and the determination at SA6 is affirmative, the learning at SA7 is performed. After the learning control of the control means 144 is permitted, in SA8 corresponding to the line pressure switching means 154, the holding of the line pressure at the start of the inertia phase, that is, the back pressure value P _Li is released, and the line pressure control means is set. The line pressure control based on the input torque T _IN by 142 is switched. Further, after the start of the inertia phase and before the rotation synchronization determination, for example, when the throttle pedal is stepped on, the determination in SA5 is negative, so the SA8 corresponding to the line pressure holding release means 152 is determined. At the time, the holding of the line pressure at the start of the inertia phase, that is, the back pressure value P _Li is released, and the line pressure control is switched to the line pressure control based on the input torque T _IN .

In the line pressure limit control of FIG. 11, SB
At 1, it is determined whether or not the 4 → 3 downshift is being performed.
If the determination at SB1 is negative, this routine is ended, but if the determination is affirmative, at S2 the above S
It is determined whether or not the rotation synchronization determination by A6 has been performed.
If the determination in SB2 is negative, the routine is terminated, but if the determination is affirmative, it is determined in SB3 whether the actual drive signal D _SLT is smaller than the drive signal D _SLTi at the start of the inertia phase. To be judged. If the determination at SB3 is negative, the routine is ended, but if the determination is affirmative, at SB4 corresponding to the line pressure limiting means 158, the actual content of the drive signal D _{SLT is} the time when the inertia phase starts. Drive signal D _SLTi to replace the drive signal D when the inertia phase starts
It is restricted to be less than _SLTi .

As described above, according to this embodiment, the variable speed opening is performed.
4 → 3 downshift by starting point determination means 146 (SA2)
When the starting point of the line pressure is determined, the line pressure holding means 14
8 (SA4), the line pressure P at the time when the shift start is determined_Li
Is held for the subsequent gear shifting period,
After that, the line pressure P at the time when the shift start is determined is determined._LiBut
Connected to brake B1 and clutch C1 involved in gear shifting
B1 accumulator A_B1And C1 Accumley
Type A_C1Used as back pressure. Therefore, during the shift period
That is, the accelerator pedal during the period of inertia phase
There is a change in the dull operation amount or a change in the engine speed.
Even if the above, B1 accumulator A _B1And C1
Cumulator A_C1Back pressure is not affected
Therefore, the learning condition of the learning control means 144 is stable and good.
A variety of learning control effects can be obtained.

Further, according to the present embodiment, the engine load change judging means 150 (for judging whether or not the engine load has changed within the gear shift period after the gear shift start point judged by the gear shift start point judging means 146 ( SA5) and the engine load change determining means 150 determines that the engine load has changed, the line pressure holding releasing means for releasing the line pressure holding means 148 (SA4) from holding the line pressure. 152 (SA8) is further included. Accordingly, the input torque T of the automatic transmission 14
_{When the} engine load changes such that _IN increases rapidly, the line pressure holding releasing means 152 releases the line pressure holding means 148 from holding the line pressure. The slippage of the brake B1 and the clutch C1 due to the rapid increase of the input torque is preferably prevented.

Further, according to this embodiment, after the shift start point, the input shaft rotation speed N _IN of the automatic transmission 14 is the rotation speed after the gear shift, that is, the rotation speed (G) in the third gear.
₃ × N _C ). The rotation synchronization determining means 154 (SA6) for determining whether or not the input shaft rotation speed N _IN of the automatic transmission 14 is synchronized with the rotation speed after shifting. If it is determined that the line pressure is determined, the line pressure P _Li held by the line pressure holding unit 148 is determined by the line pressure control unit 142 based on the input torque T _IN of the automatic transmission 14. Line pressure switching means 156 (SA8) for switching to the pressure P _L is further included. As a result, when it is determined that the input shaft rotation speed N _IN of the automatic transmission 14 is synchronized with the rotation speed after the shift (G ₃ × N _C ), the line pressure switching means 156 holds the line pressure holding means 142. Since the line pressure P _Li is changed to the line pressure P _L determined based on the input torque T _IN of the automatic transmission 14, the input shaft rotation speed N _{IN of the} automatic transmission 14 is synchronized with the rotation speed after the shift. Slip of the brake B1 and the clutch C1 is preferably prevented from occurring in the period after it is determined that the slip has occurred.

Further, according to this embodiment, the line pressure P _L switched by the line pressure switching unit 156 is provided with the line pressure limiting unit 158 for limiting the line pressure P _L so as not to fall below the line pressure P _Li at the time of determining the shift start. Has been. As a result, the line pressure P _L after the input shaft rotation speed N _IN of the automatic transmission 14 is synchronized with the rotation speed (G ₃ × N _C ) after the gear shift does not fall below the line pressure P _Li at the time of the gear shift start determination. Therefore, slippage of the brake B1 and the clutch C1 is preferably prevented.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, the shift start point determination means 146 of the above-described embodiment determines the inertia phase start point as the shift start point within the 4 → 3 shift control period. But,
Even if the 4 → 3 shift output point or the torque phase start point is determined as the shift start point and the line pressure P _{Li at} that time is held, the learning condition of the learning control unit 144 is stabilized. The effect is obtained.

Further, in the above-described embodiment, the line pressure holding means 148 holds the line pressure P _Li at the time of the gear shift start determination until the rotation synchronization determination means 154 determines the rotation synchronization. Until then, for example, it may be maintained until the end time t _{4 of the} 4 → 3 shift control period.

Further, in the above-mentioned embodiment, the 4 → 3 shift is explained, but other shifts may be adopted depending on the configuration of the automatic transmission 14.

The automatic transmission 14 described above may be constructed so as to have five forward gears, and the engine brake range in which the shift lever 88 is operated is between the 2 range and the D range. It may be provided with three ranges.

In the above embodiment, the line pressure limiting means 158 or the line pressure limiting control routine shown in FIG. 11 does not necessarily have to be provided.

The above description is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration of a vehicle power transmission device including a control device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a shift speed achieved by a combination of operations of friction engagement devices provided in the automatic transmission of FIG.

FIG. 3 is a block diagram schematically illustrating a main configuration of a hydraulic control device that controls the automatic transmission of FIG.

FIG. 4 is a hydraulic circuit diagram for specifically explaining a hydraulic circuit configuration of the source pressure generator of FIG.

5 is a functional block diagram illustrating a main part of a control function of the electronic shift control device of FIG. 1. FIG.

FIG. 6 is a time chart for explaining the operation of gear shift transient control of the gear shift electronic control device of FIG. 1;

FIG. 7 is a diagram illustrating characteristics of the linear solenoid valve SLT of FIG.

8 is a diagram showing a relationship for determining a drive signal D _SLT based on an input torque T _IN in the line pressure control means of FIG.

9 is a diagram showing a line pressure control characteristic of the line pressure control means of FIG.

10 is a flowchart illustrating a control operation of the electronic shifting control device of FIG. 1, and is a diagram illustrating a line pressure control routine during shifting.

FIG. 11 is a flowchart illustrating a control operation of the electronic shift control device of FIG. 1, showing a line pressure limit control routine.

[Explanation of symbols]

14: Automatic transmission 144: Learning control means 146: Shift start point determining means 148: Line pressure holding means 150: Engine load change determination means 152: Line pressure holding release means 154: Rotation synchronization determination means 156: Line pressure switching means B2 brake: (hydraulic friction engagement device) B1 brake: (hydraulic friction engagement device)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Ozeki 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor Toshinari Suzuki, 1 Toyota Town, Aichi Prefecture Toyota Motor Corporation, ( 72) Inventor Masafumi Kinoshita 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) Reference JP 9-42431 (JP, A) JP 4-136561 (JP, A) JP 3-249466 (JP, A) JP 5-280625 (JP, A) JP 7-127721 (JP, A) JP 1-193445 (JP, A) JP 2-154856 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] 1. In a vehicular automatic transmission in which a gear stage is selected by a combination of operations of a plurality of hydraulic friction engagement devices, a gear transition is performed by using a line pressure which is a source pressure of the hydraulic friction engagement devices. A control device of a type for controlling hydraulic pressure and learning control of a line pressure within a shift period based on the shift state, the shift start point determining means for determining a start point of the shift, and the shift start point determining means. When the start point of the shift is determined by the means, the line pressure holding means for holding the line pressure at that time in the subsequent shift period and the shift start point
After that, after the input shaft rotation speed of the automatic transmission is changed
Rotation synchronization judgment hand to judge whether or not it is synchronized with the rotation speed of
Stage and the input shaft rotation of the automatic transmission by the rotation synchronization determination means
If it is determined that the speed is synchronized with the rotation speed after shifting,
Is the line pressure held by the line pressure holding means?
From the input torque of the automatic transmission.
A line pressure switching means for switching to the in-pressure and a line pressure switched by the line pressure switching means,
Limit not to fall below the line pressure when the shift start is judged
And a line pressure limiting means for controlling the automatic transmission for a vehicle. 2. An engine load change determining means for determining whether or not an engine load has changed within a shift period after the shift start point, and the engine load change determining means for determining that the engine load has changed. The control device for an automatic transmission for a vehicle according to claim 1, further comprising: a line pressure holding release means for releasing the holding of the line pressure by the line pressure holding means.