JP2002089681A - Variable speed control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable speed control device capable of preventing a push-up shock or the generation of a backlash hammering noise of backlash between gears in a geared shifting mechanism of an automatic transmission in the automatic transmission in which a first friction element of plural friction elements is connected by increase in operating oil pressure and in response to a pressure signal related to the operating oil pressure of the first friction element, in the lapse of a preset time, a second friction element is released by lowering of the operating oil pressure to perform shifting operation by switching engagement of the friction elements. SOLUTION: In the automatic transmission, in shifting operation by switching engagement of the friction elements, after the end of loss stroke of the first friction element is detected, the operating oil pressure related to the second friction element is lowered with a preset gradient, and the operating oil pressure related to the first friction element is increased with a designated gradient, the oil pressure in detecting the end of the loss stroke is set a little larger than the operating oil pressure at the end of the actual loss stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control device for engaging a first friction element among a plurality of friction elements and transmitting a pressure signal relating to an operating oil pressure of the first friction element. The present invention relates to a shift control device for suitably performing a shift performed by changing a friction element that releases a second friction element after a set time has elapsed.

[0002]

2. Description of the Related Art An automatic transmission determines a power transmission path (gear stage) of a gear transmission system by selectively hydraulically operating (engaging) a plurality of friction elements such as clutches and brakes.
The shift to another shift speed is performed by switching the operated friction element.

[0003] Since the automatic transmission has such a configuration, the first friction element of the plurality of friction elements is fastened by increasing the operating oil pressure and receives a pressure signal related to the operating oil pressure of the first friction element. After the set time, there is a shift that is performed by changing the friction element, that is, releasing the second friction element by lowering the operating oil pressure. In the present specification, a friction element to be switched from the engaged state to the released state during the shift change is referred to as a release-side friction element, and its operating oil pressure is referred to as a release-side operating oil pressure, and a friction element to be switched from the released state to the engaged state is referred to as a friction element. The engagement side friction element and its operating oil pressure are referred to as engagement side operation oil pressure.

[0004] At the time of the shift change, the control for lowering the release-side hydraulic pressure for releasing the release-side friction element and the control for increasing the engagement-side hydraulic pressure for engaging the engagement-side friction element are conventionally shown in, for example, FIG. Go as shown.
That is, as shown in FIG. 12 (a), by increasing the engagement side hydraulic pressure P _C from the shift command instant t _1, is stroked against the engagement side frictional element to the return spring, stroke loss engagement side frictional element that the was _{terminated, P} C =
It is detected by the oil pressure switch to ON when it becomes P _1.

[0005] release-side hydraulic pressure _{P O} is the shift command instant _{t 1}
Loss stroke of the engagement side friction element from the end detection instant t ₂
Until the release side frictional element is reduced rapidly to P ₄ to be the engagement capacity just before starting to slip during subsequent to time t ₅ reduces slowly as the above changeover is made, rapidly thereafter To 0. In the engagement side hydraulic pressure P _C and the other, to jump to the initial shelf pressure P ₂ for by starting the above changeover to terminate the torque phase to the loss stroke completion detection instant t ₂ after the engagement side frictional element, the instant t ₃ between to time t _6, allowed to reach a pressure P ₃ which the inertia phase is completed further raised at a predetermined slow shelf pressure gradient is increased to a maximum value during a subsequent to time t _7.

[0006]

In [0008] Meanwhile the conventional shift control device described above, the value P ₁ of the engagement side hydraulic pressure P _C at the time of ON of the hydraulic pressure switch, than the actual value P ₀ at loss stroke ends values greater, specifically, is set to 50kPa about greater than for example P _0. Therefore, the following problem occurs.

Here, when the control operation shown in FIG. 12 (a) is performed, the transmission output torque T _OUT and the turbine speed N _t (the transmission input rotation speed) in the upshift operation, particularly when the throttle opening TVO is low. Number) and transmission output speed N
The time series change of _O is as shown in FIG. 12 (b) and FIG. 12 (c), respectively. As is apparent from FIG. 12 (b), the transmission output torque T _OUT has a large torque decrease (pull-in) T _OT in the torque phase, and the time from when the torque decreases until it reaches the minimum value (the pull-in). Time) is also longer. This is pull T _{O T} of the torque to temporarily negative value transmission output torque T _OUT with the torque phase, causing the zero crossing of the subsequent return to a positive value so-called transmission output torque, generates a large push-up shock immediately thereafter This has an adverse effect on the operability of the vehicle, such as causing backlash between the gears in the gear transmission mechanism of the automatic transmission.

[0008] This phenomenon, because it sets the detected pressure P ₁ at the time of ON the oil pressure switch as described above, a relatively larger value than the actual value P ₀ at loss stroke end, the engagement side Hydraulic control is performed when the engagement capacity of each of the friction element and the release-side friction element has increased to some extent.

To solve such a problem, for example, FIG.
It is conceivable to perform control as shown in (a). In the control shown, the loss stroke end detection instant t ₂ after the engagement side frictional element, the engagement side hydraulic pressure P _C, After soaring to an initial shelf pressure P ₂ to terminate the torque phase, is once lowered, and then We are going to raise it again.

However, such control also has the following problems. When the control operation shown in FIG. 13A is performed, the transmission output torque T _OUT , turbine speed N _t (transmission input speed) and transmission output in an upshift operation, particularly when the throttle opening TVO is low. The time-series changes in the rotational speed N _O are as shown in FIGS. 13 (b) and 13 (c), respectively. 13 when performing the control operation shown in (a), by variations in the components of the automatic transmission, engagement side hydraulic pressure P _C is the actual value P at the end loss stroke ₀
It can be smaller than At this time, a response delay occurs due to the piston stroke operation being performed again, and a shift occurs in the shift start timing (changeover shift timing). Due to this timing shift,
A sudden increase in engine speed (blazing) occurs. As a result, as shown in FIG. 13 (b), retraction of the torque T _OT
Becomes large (deep), and the pulling time becomes long. In addition, a large thrust shock occurs immediately after the occurrence of the idling.

According to the first aspect of the present invention, in a shift operation under a low load such as during an upshift with a low throttle opening, the engagement side operating oil pressure is particularly controlled at a low pressure corresponding to the load. Based on the fact that it is necessary, the detection pressure when turning on the hydraulic switch, which triggers the control operation, is set to a value slightly larger than the actual value at the end of the loss stroke, It is an object of the present invention to solve the above-described problem that has occurred in a conventional device.

A second object of the present invention is to secure the above-mentioned effects by setting an upper limit value of the detected pressure when the hydraulic switch is turned on.

A third object of the present invention is to further secure the above-mentioned effects by setting a specific value for the upper limit.

[0014]

SUMMARY OF THE INVENTION To attain these objects, a shift control device for an automatic transmission according to a first aspect of the present invention first engages a first friction element among a plurality of friction elements by increasing an operating hydraulic pressure. Receiving a pressure signal related to the operating oil pressure of the first friction element, releasing the second friction element by lowering the operating oil pressure after a set time, and changing the speed by shifting the first and second friction elements. Upon the change, after the end of the loss stroke of the first friction element is detected, the operating oil pressure related to the second friction element is reduced at a set gradient, and the operating oil pressure related to the first friction element is set to a predetermined value. In the automatic transmission configured to increase at a gradient, the hydraulic pressure for detecting the end of the loss stroke is set to be slightly larger than the actual operating pressure at the end of the loss stroke. It is characterized in.

According to a second aspect of the present invention, in the shift control device for an automatic transmission according to the first aspect, the upper limit value of the hydraulic pressure at the time of detecting the end of the loss stroke is determined by the sum of the operating oil pressure at the end of the loss stroke and a predetermined value. Is also reduced.

According to a third aspect of the present invention, there is provided a shift control device for an automatic transmission according to the second aspect, wherein the predetermined value is set to 50 kPa or less.

[0017]

According to the present invention, a first friction element (fastening-side friction element) among a plurality of friction elements is fastened by an increase in working oil pressure, and after a pressure signal relating to the working oil pressure of the fastening-side friction element is received, after a set time, At the time of the shift change of the automatic transmission in which the second friction element (release-side friction element) is released by lowering the operating oil pressure, it is detected that the engagement-side friction element has completed the loss stroke due to the increase in the operating oil pressure. Then, the shift speed is advanced by decreasing the operating oil pressure related to the disengagement side friction element at a set gradient and increasing the operating oil pressure related to the engagement side friction element at a predetermined slope.

In the first invention, since the hydraulic pressure at the time of detecting the end of the loss stroke is set slightly larger than the actual operating hydraulic pressure at the end of the loss stroke, each of the engagement-side friction element and the release-side friction element is set. The hydraulic control is performed from the state where the engagement capacity of is small.

Therefore, it is possible to prevent a large torque pull-in in the torque phase and a long pull-out time, whereby the transmission output torque zero cross and the transmission torque zero cross can be prevented.
It is possible to avoid a large thrust immediately after that and a backlash between gears in the gear transmission mechanism of the automatic transmission.

Further, in the second invention, since the upper limit value of the detected oil pressure when the hydraulic switch is turned on is set, the difference between the detected oil pressure value and the actual value at the end of the loss stroke is reduced. The operation and effect of the first invention can be ensured.

In the third aspect of the invention, the upper limit value is specifically set to a value lower than the conventional detected hydraulic pressure, so that the operation and effect of the first aspect of the invention can be further ensured. .

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a shift control device for an automatic transmission according to an embodiment of the present invention, wherein 1 is an engine, and 2 is an automatic transmission. The output of the engine 1 is adjusted by a throttle valve whose opening increases from fully closed to fully opened as the driver steps on the accelerator pedal operated by the driver, and the output rotation of the engine 1 is automatically transmitted through the torque converter 3. It is assumed that the signal is input to the input shaft 4 of the transmission 2.

The automatic transmission 2 is arranged in a coaxial butting relationship.
Flow from the engine 1 side on the input / output shafts 4 and 5
Top planetary gear set 6 and rear planetary gear set 7
And the planetary gears in the automatic transmission 2.
This is the main component of the vehicle transmission mechanism. Close to engine 1
The front planetary gear set 6 includes a front sun gear
S _F, Front ring gear R_F, Which meshes with these
Toppinion P_F, And the front pinion
Front Carrier C_FSimple planetary teeth consisting of
Rear planetary gear set 7 far from engine 1
Also, rear sun gear S _R, Rear ring gear R_RTo these
Rear pinion P meshing_R, And the rear pinion
Rear carrier C that supports it freely_RSimple planetary teeth consisting of
Assume a car set.

The low clutch L / C, the second gear, the fourth gear, and the like are friction elements that determine the transmission path (gear position) of the planetary gear transmission mechanism.
Speed brake 2-4 / B, high clutch H / C, low reverse brake LR / B, low one way clutch L / OWC, and reverse clutch R / C are correlated with the components of both planetary gear sets 6, 7 as follows. To be provided. In other words, the front sun gear S _F is the input shaft 4 by the reverse clutch R / C
And 2nd / 4th speed brakes 2-4 /
It can be fixed appropriately by B.

The front carrier _CF is a high clutch H / C.
Can be connected to the input shaft 4 as appropriate. Front carrier C _F is further well as prevent rotation of the engine rotation and reverse direction by the low one-way clutch L / OWC, and suitably fixable by the low reverse brake LR / B. The front carrier _{C F,} between the rear ring gear _{R R,}
The low clutch L / C can be connected appropriately. Between front ring gear R _F and the rear carrier C _R bonded to each other, these front ring gear R _F and the rear carrier C _R is connected to the output shaft 6, the input shaft 4 to the rear sun gear S _R
To join.

The power transmission train of the above-mentioned planetary gear transmission mechanism has a selective hydraulic pressure indicated by a solid line 〇 in FIG. 2 for friction elements L / C, 2-4 / B, H / C, LR / B, and R / C. Actuation (engagement) and self-engagement of the low one-way clutch L / OWC as indicated by the solid line 同 in the same figure, the first forward speed (1st), the second forward speed (2nd), and the third forward speed (3
rd), forward fourth speed (4th) forward speed, and reverse speed (Re
v) and can be obtained. The hydraulic operation (fastening) indicated by a dotted line in FIG. 2 is a friction element to be operated when engine braking is required.

The shift control friction elements L / C, 2-4 /
The engagement logic of B, H / C, LR / B, and R / C is realized by a control valve body 8 shown in FIG. 1. In addition to a manual valve (not shown), the control valve body 8 has a line pressure solenoid 9, Low clutch solenoid 1
0, 2nd and 4th speed brake solenoid 11, high clutch solenoid 12, low reverse brake solenoid 13, etc. are inserted.

The line pressure solenoid 9 switches the line pressure, which is the source pressure of the shift control, between high and low by turning on and off the line pressure solenoid 9.
The manual valve (not shown) is operated by the driver in accordance with the desired traveling mode, such as forward traveling (D) range position, backward traveling (R).
It is assumed that the vehicle is operated to the range position or the parking / stop (P, N) range position. In the D range, the manual valve uses the above line pressure as the base pressure, and uses the low clutch solenoid 10, the 2nd / 4th speed brake solenoid 11, and the high clutch solenoid.
12, low clutch L / C, 2nd / 4th speed brake 2-4 / B, high clutch H / C, low reverse brake LR / B corresponding to duty control of low reverse brake solenoid 13.
It is assumed that the line pressure is supplied to a predetermined circuit so that the operating hydraulic pressure of each of the solenoids can be individually controlled, and the duty logic of each of the solenoids realizes the first to fourth speed engagement logics shown in FIG. However, in the R range, the manual valve directly supplies the line pressure to the reverse clutch R / C and the low reverse brake LR / B without depending on the duty control of each of the above-mentioned solenoids, and these are engaged to operate as shown in FIG. It is assumed that the reverse logic shown is realized.
In the P and N ranges, the manual valve does not supply the line pressure to any circuit, and makes the automatic transmission neutral by releasing all friction elements.

The ON / OFF control of the line pressure solenoid 9 and the duty control of the low clutch solenoid 10, the second / fourth speed brake solenoid 11, the high clutch solenoid 12, and the low reverse brake solenoid 13 are executed by the transmission controller 14, respectively. For this purpose, the transmission controller 14 includes a signal from a throttle opening sensor 15 for detecting a throttle opening TVO of the engine 1 and a turbine rotation speed N which is an output rotation speed (transmission input rotation speed) of the torque converter 3. _t , a signal from an output rotation sensor 17 for detecting the number of rotations N _O of the output shaft 5 of the automatic transmission 2, a signal from an inhibitor switch 18 for detecting a selected range, The engagement-side friction element to be engaged during the shift change, that is, as shown in FIG. Clutch H / C, 2nd / 4th speed brake 2-4 / B for 3 → 2 shift, 2nd / 4th speed brake 2-4 / B for 3 → 4 shift, Low clutch L for 4 → 3 shift / C
The signal from the hydraulic switch group 19 arranged in the inside is input respectively. Here, the hydraulic switch group 19 is turned on when the operating oil pressure of the corresponding friction element reaches a pressure at which the loss stroke of the friction element ends and the engagement capacity starts to be generated.

FIG. 3 schematically shows a hydraulic control system of the transmission control device shown in FIG. 1, wherein reference numeral 20 denotes a line pressure oil passage, reference numeral 21 denotes a manual valve, reference numeral 22 denotes a D range pressure oil passage, and reference numeral 23 denotes an R range pressure. It is an oilway. The manual valve 21 is a valve that is switched by a selection operation performed by a driver's shift lever operation. The manual pressure valve 21 is connected to the line pressure oil passage 20 and the D range pressure oil passage 22 in the D range, and is connected to the line pressure oil passage 20 in the R range.
And the R range pressure oil passage 23 are connected.

Reference numeral 24 denotes a pilot valve, 25 denotes a pilot pressure oil passage, and the pilot valve 24 is a line pressure oil passage.
This is for reducing the line pressure from 20 to a constant pilot pressure.

Reference numeral 26 denotes a first pressure control valve, which is a low clutch amplifier valve and a low clutch solenoid 10 (see FIG. 1).
The low clutch pressure is generated from the D range pressure and guided to the low clutch L / C via the low clutch pressure oil passage 27.

Reference numeral 28 denotes a second pressure control valve, which is a high clutch amplifier valve and a high clutch solenoid 12 (see FIG. 1).
The high clutch pressure is generated from the D range pressure, and is guided to the high clutch H / C via the high clutch pressure oil passage 29.

Reference numeral 30 denotes a third pressure control valve, which is a 2-4 brake amplifier valve and a 2-4 brake solenoid 11 (see FIG. 1).
To produce 2-4 brake pressure from D range pressure,
It is led to the 2-4 brake 2-4 / B via the brake pressure oil passage 31.

Reference numeral 32 denotes a fourth pressure control valve, which has a low reverse brake amplifier valve and a low reverse brake solenoid 13 (see FIG. 1), generates low reverse brake pressure from the D range pressure, and supplies a low reverse brake pressure oil passage. 33
To the low reverse brake LR / B.

Reference numeral 34 denotes a lock-up solenoid for controlling engagement and release of the lock-up clutch.

FIG. 4 shows the structure of the first pressure control valve 26 shown in FIG. The first pressure control valve 26 is a solenoid valve 9 (see FIG. 1) for controlling the solenoid valve supply pressure (pilot pressure) to the spool supply pressure by duty control (control by a pulse width modulation method) for applying a duty drive current to the solenoid coil. ) And the spool signal pressure oil passage 35
And a spool valve 36 that operates using the oil pressure from the spool signal pressure oil passage 35 as a signal pressure and controls the D range pressure to a low clutch pressure.

FIG. 5 is a graph showing the characteristics of the solenoid drive current, solenoid output pressure and command pressure of the solenoid valve in the pressure control valve of the transmission control device shown in FIG. In this solenoid valve, the driving current corresponding to the command pressure P _A that is computed by the transmission controller 14 (see FIGS. 1 and 3) is output to the solenoid, whereby the hydraulic pressure P corresponding to the drive current _S will be output.

To explain the automatic shifting operation in the D range to which the present invention relates, the transmission controller 14 executes a control program (not shown) to execute the throttle opening TVO and the transmission output based on a predetermined shift map. Rotation speed N _O (vehicle speed)
, A suitable gear required in the current operating state is searched. Next, the transmission controller 14 determines whether or not the currently selected gear position matches the preferred gear position. If the gear ratio does not match, the transmission controller 14 issues a shift command to execute the gear shift to the preferred gear position, that is, FIG. Based on the engagement logic table, the operating oil pressure of the friction element is changed by duty control of the solenoids 10 to 13 so that engagement and release switching of the friction element for the shift is performed.

Here, the shift between the second speed and the third speed and the third speed
As in the case of the shift between the fourth speed and the fourth speed, a shift change in which a certain friction element is released by lowering the operating oil pressure and another friction element is engaged by increasing the operating oil pressure is described. drive upshift time associated with but for example the vehicle speed increases in the forward drive state (driving state of the engine brake and reverse) is to release side working oil pressure command value P _O and fastening a command value of the hydraulic pressure of the friction element to be released command value at which the engagement side working oil pressure command value P _C of the working oil pressure of the friction elements to be
Are given as shown in FIG. 11 (a).

[0042] Such changeover transmission controller 14 to perform the gear shift, disengagement side working oil pressure command value P _O and the engagement side working oil pressure command value P _C by a program shown in FIG. 6
Are controlled in time series. Here, FIG. 6 shows a main routine, and FIGS. 7 to 10 each show a subroutine. In the program of FIG. 6, first, in step 41,
Initialize for Phase 1 from the shift command instant t ₁ shown in FIG. 11 (a) to time t ₂ when the oil pressure switch 19 turns ON, the
In the next step 42, a determination of the release-side hydraulic pressure command value P _O and the engagement side working oil pressure command value P _C in Phase 1 is performed by the subroutine of FIGS.

In step 43, it is determined whether or not the hydraulic switch 19 of the engagement-side friction element has been turned ON. In other words, it determines the engagement side frictional element is beginning to have engagement capacity to exit the loss stroke, whether reached instantaneously t ₂ in FIG. 11 (a). Up to the instant t ₂ in FIG. 11 (a) running (subroutine shown in i.e. Figure 4 and Figure 5) Step 42,
Continuing the control of the disengagement side hydraulic pressure command value P _O and the engagement side working oil pressure command value P _C in Phase 1.

Here, the hydraulic switch 19 for the engagement-side friction element
, Which is a threshold value for determining whether or not is turned on, that is, the loss stroke end detection oil pressure P _LS is slightly smaller than the actual oil pressure P _LE of the engagement side friction element at the end of the loss stroke by a predetermined value ΔP. Set to large. Specifically, the value of P _LS is

## EQU1 ## It is assumed that P _LE <P _LS <P _LE + ΔP is within a certain range. Here, the value of the predetermined value ΔP is

## EQU2 ## Set ΔP ≦ 50 kPa. Note that the value of 50 kPa corresponds to the hydraulic switch 19
Is a value that takes into account the variation in the precision.

[0045] When the oil pressure switch 19 of the engagement side frictional element at step 43 is determined to have turned ON, proceed to step 44 to control instant t ₂ of FIG. 11 (a), O of the oil pressure switch 19 shown in FIG. 11 (a)
Initialize for Phase 2 from the N instantaneous t ₂ to set time Delta] t _S has elapsed, the next step 45, the release-side working oil pressure command value in the phase 2 P _O and the engagement side working oil pressure command value P _C Is determined by the subroutine of FIGS. 9 and 10.

In step 46, the hydraulic switch 1 shown in FIG.
Timer TM ₂ for measuring the elapsed time from the ON instant t ₂ of 9
Indicates that the shift end determination set time Δt _S has elapsed, that is, whether phase 2 has been completed. Here, if TM ₂ <Δt _S and phase 2 has not been completed yet, step 45 (ie, the subroutine shown in FIGS. 9 and 10) is executed to release the release-side operating oil pressure command value _PO and the engagement side in phase 2. hydraulic pressure command value _{P C}
It continued control of, whereas TM in Phase 2 is ₂ ≧ Delta] t _S ends the control if completed.

[0047] indicated by the subroutine of FIG. 7, in describing the control mode of the disengagement side hydraulic pressure command value P _O in Phase 1, first in step 51, the hydraulic pressure according to the disengagement side working oil pressure command value P _O in Phase 1 _Is set to a predetermined value _PO1 . This value is the oil pressure value P _L (ie, line pressure) in FIG.

Next, at step 52, the hydraulic switch 19
11 is read, and in step 53, it is determined whether or not the hydraulic switch 19 is ON, that is, the engagement-side friction element has completed the loss stroke and has started to have the engagement capacity.
It determines whether or not led to the instant t ₂ of (a). During up to instant t ₂ in FIG. 11 (a), hydraulic pressure command value P _O at step 54, is lowered to the set value P ₅ before, continuing the control by the repetition of step 52 to step 54 I do. When then 11 that led to the instant t ₂ of (a), control proceed to step 55 to end the control of the disengagement side hydraulic pressure command value P _O in Phase 1, the release-side in Phase 2 shown in FIG. 9 shifts to the control of the hydraulic pressure command value P _O. Therefore, in the phase 1, the release-side operating oil pressure command value _PO becomes:
As shown in FIG. 11 (a), the above-mentioned set value _PO1 is set.

The control of the engagement side working oil pressure command value P _C in the same phase 1 are those such shown in FIG. 8, first in step 61, an initial value P _{C 0} of the engagement side working oil pressure command value P _C. In the next step 62, FIG.
(elapsed time from the start of Phase 1) elapsed time from the shift command instant t ₁ of (a) to start the timer TM ₁ for measuring the.

Next, at step 63, the hydraulic switch
The signal from step 19 is read, and based on this, in step 64, it is determined whether or not the hydraulic switch 19 is ON, that is, the engagement-side friction element has finished the loss stroke and has started to have the engagement capacity.
It determines whether or not led to the instant t ₂ of (a). Figure 11 at step 45 until reaching the instant t ₂ of (a), the engagement side working oil pressure command value P _C is Figure from the initial oil pressure P _C0 11 (a)
To increase at a predetermined gradient alpha shown in computing equation P _{C0 +} α ×
The TM ₁ Request engagement side working oil pressure command value _{P C.} Here predetermined gradient α above, the instant t ₂ of Figure 11 the engagement side working oil pressure command value P _C to terminate the loss stroke of the engagement side frictional element (a), the range engagement shock of the engagement side frictional element does not occur , The loss stroke of the engagement-side friction element is completed in the shortest time.

Thereafter, in step 64, the hydraulic switch 19
Is determined to be ON, instant t in FIG. 11 (a).₂Control
Proceed to step 66, where the timer TM of phase 1₁To 0
After the reset to
Engagement hydraulic pressure command value P _CControl is completed, and FIG.
Engagement-side operating oil pressure command value P in phase 2 shown_Cof
Transfer to control. Therefore, operation on the fastening side in phase 1
Oil pressure command value P_CAs shown in FIG. 11 (a),
Time t₁Above the initial hydraulic pressure P_C0Stepped up to
And then the initial hydraulic pressure P_C0From a predetermined gradient α
Value, which is the value at which the fastening-side friction element starts to have the fastening capacity.
You.

[0052] indicated by the subroutine of FIG. 9, to explain a control mode of the disengagement side hydraulic pressure command value P _O in Phase 2, first in step 71, the initial related to disengagement side working oil pressure command value P _O in Phase 2 Set the hydraulic pressure. In addition,
The value of the initial oil pressure is P ₅ in FIG. 11 (a).

[0053] In step 72, to start the timer TM ₂ for measuring the FIG 11 (a) the oil pressure switch (19) the elapsed time from the ON instant t ₂ of (the elapsed time from the start of Phase 2). Next, at step 74, the throttle opening TV
O Reads, in step 74, on the basis of a map showing the relation between the change gradient beta of the disengagement side hydraulic pressure specified value P _O with the throttle opening TVO, not shown, to search for the change gradient beta.

[0054] Then, in step 75, and checks whether the disengagement side working oil pressure command value P _O is lowered to 0, during the step 76 until the release-side working oil pressure command value P _O is lowered to 0, release side as hydraulic pressure command value P _O is lowered at a predetermined gradient as shown in FIG. 11 (a) from the initial oil pressure, obtaining an equation P _O-beta × disengagement side operated by TM ₂ oil pressure command value P _O . In FIG. 11 (a), this β
The value, and beta ₁ from the instantaneous _{t 2} to _{t 4,} is a beta ₂ from the instantaneous _{t 4} to _{t 5.}

When it is determined in step 75 that the release-side operating oil pressure command value _PO has decreased to 0, in step 77, a timer TM2 for measuring the elapsed time from the start of the phase ₂
Is longer than the set time Δt _S for determining the end of the shift shown in FIG. 11 (a), and the control is returned to step 75 until TM ₂ ≧ Δt _S and the release-side operating oil pressure command value P _O Is maintained at 0. Then, step 77 when determining the TM ₂ ≧ Delta] t _S, and resets the timer TM ₂ to 0 in step 78, and ends the control of the disengagement side hydraulic pressure command value P _O in Phase 2 in step 79. Therefore, in the phase 2, the release-side operating oil pressure command value _PO is _calculated as shown in FIG.
As shown in, setting the hydraulic pressure P _O in Phase 1 is a predetermined gradient beta (beta ₁ and beta ₂₎ it is reduced by finally becomes 0, thereby decreasing the torque capacity of the disengagement side frictional element.

[0056] Control of the engagement side working oil pressure command value P _C in the same phase 2 intended such shown in FIG. 10, first, the initial hydraulic pressure P of the engagement side working oil pressure command value P _C in step 81
_C2 is set, and the initial hydraulic pressure _PC2 is determined by the hydraulic switch 19 being turned ON after the engagement-side friction element has completed the loss stroke.
At the instant t ₂ of the 11 (a), i.e. the value of the engagement side working oil pressure command value P _C at the end of phase 1. In addition,
Initial oil pressure _{P C2} is that the _{P 2} in FIG. 11 (a). In the next step 82, the hydraulic switch (19) shown in FIG.
Starting the timer TM ₂ for measuring the instantaneous t ₂ elapsed time from (elapsed time from the start of Phase 2).

Next, at step 83, the throttle opening
TVO reads, at step 84, based on the map showing the relationship between a change gradient γ of the release-side hydraulic pressure specified value P _C and the throttle opening TVO which is not shown, the change gradient γ
Search for. In the next step 85, the throttle opening TVO
Then, a shelf pressure _PT corresponding to this is searched, and this shelf pressure _PT is a pressure for terminating the inertia phase in a short time within a range in which no shift shock occurs, as is well known.

[0058] Then, in step 86, while the engagement side working oil pressure command value P _C is checked whether increased to shelf pressure P _T, the engagement side working oil pressure command value P _C rises to shelf pressure P _T, Step in 87, so that the engagement side working oil pressure command value P _C is increased at a predetermined gradient gamma shown in FIG. 11 (a) from the initial hydraulic pressure P _C2 (P _2), fastened by a calculation of the arithmetic expression P _{2 +} γ × TM ₂ Request side hydraulic pressure command value P _C. Here, shelf pressure P _T is what is labeled as Figure 11 P ₃ in (a). In FIG. 11A, the value of γ is the instant t ₂
From to _{t 6} and γ _1, is set to γ ₂ from the instant _{t 6} to _{t 7.}

[0059] When the engagement side working oil pressure command value P _C in step 86 is determined to have increased to shelf pressure P _T (P _3), the steps
In 88, it is determined whether or not the timer TM ₂ for measuring an elapsed time from the start of Phase 2 is shown to shift end or determination setting period Delta] t _S shown FIG _{11 (a), TM 2 ≧} Δ
control until t _S returns to step 86 to maintain the engagement side working oil pressure command value P _C in shelf pressure P _T. And step
When 88 to determine the TM ₂ ≧ Delta] t _S, and resets the timer TM ₂ to 0 in step 89, the engagement-side working oil pressure command value P _C in the same maximum value as the line pressure P _L is the original pressure at step 90, It terminates the control of the engagement side working oil pressure command value P _C in phase 2 in step 91.

[0060] with time increase the disengagement side working oil pressure command value P _O over time decreases and the engagement side working oil pressure command value P _C by more, changeover of both is fastened engagement side frictional element with the release-side friction element is released Is performed, and a predetermined shift change is performed. Incidentally in the above-described embodiment, a trigger for controlling the temporal increase in the release-side hydraulic pressure command value P _O over time decreases and the engagement side working oil pressure command value P _C, respectively, the engagement side friction when turned ON oil pressure switch Since the pressure for detecting the end of the loss stroke of the element is set slightly higher than the actual pressure at the end of the loss stroke of the engagement-side friction element, the engagement capacity of each of the engagement-side friction element and the release-side friction element is small. The hydraulic control is performed from the state.

[0061] Therefore, shown in FIG. 11 (b), when as is apparent from sequence variation of the transmission output torque T _OUT, can be reduced (shallow) retraction T _OT of the torque and the pull time It is possible to shorten it. as a result,
It is possible to avoid the occurrence of an air blow, the occurrence of a large upward shock immediately after the occurrence, and the occurrence of a backlash sound between gears in a gear transmission mechanism of an automatic transmission.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing a transmission train of an automatic transmission including a shift control device according to an embodiment of the present invention, and a shift control system thereof.

FIG. 2 is a diagram showing a relationship between a selected shift speed of the automatic transmission and engagement logic of a friction element.

FIG. 3 is a diagram schematically showing a hydraulic control system of the transmission control device of FIG. 1;

FIG. 4 is a diagram showing a configuration of a pressure control valve shown in FIG.

FIG. 5 is a graph showing characteristics of the pressure control valve shown in FIG.

FIG. 6 is a control program of an engagement-side operation oil pressure command value and a release-side operation oil pressure command value when the shift control device according to the embodiment performs a shift change.

FIG. 7 is a subroutine showing a control program for a release-side operating oil pressure command value to be executed in phase 1 of the shift change;

FIG. 8 is a subroutine showing a control program for an engagement-side operating oil pressure command value performed in phase 1 of the same shift change.

FIG. 9 is a subroutine showing a control program for a release-side operating oil pressure command value performed in phase 2 of the same shift change.

FIG. 10 is a subroutine showing a control program of an engagement side operating oil pressure command value to be executed in phase 2 of the shift change.

FIG. 11 is a time chart when the shift control device according to the embodiment of the present invention performs a shift change;
(a) is a time chart showing a time-series change of the engagement side operation oil pressure command value and the release side operation oil pressure command value, (b), when controlling the engagement side operation oil pressure command value and the release side operation oil pressure command value FIG. 4C is a time chart showing a time-series change in the transmission output torque, and FIG. 5C is a time chart showing a time-series change in the turbine speed when the engagement-side working oil pressure command value and the release-side working oil pressure command value are controlled.

12A and 12B are time charts in a case where the conventional shift control device performs a shift change, in which FIG. 12A is a time chart showing a time-series change of an engagement side working oil pressure and a release side working oil pressure, and FIG. A time chart showing a time-series change of the transmission output torque when the engagement side operation oil pressure and the release side operation oil pressure are controlled at the throttle opening, (c) is the engagement side operation oil pressure and the release side operation oil pressure at a low throttle opening. 6 is a time chart showing a time-series change in the turbine rotation speed when is controlled.

FIG. 13 is a time chart of another embodiment in a case where the conventional shift control device performs a shift change, and FIG. 13 (a) is a time chart showing a time-series change of an engagement side working oil pressure and a release side working oil pressure; (b) is a time chart showing a time-series change of the transmission output torque when the engagement side operating oil pressure and the release side operating oil pressure are controlled at a low throttle opening, and (c) is an engagement side operating oil pressure at a low throttle opening. 6 is a time chart showing a time-series change in turbine speed when controlling a release-side operating oil pressure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Torque converter 4 Input shaft 5 Output shaft 6 Front planetary gear set 7 Rear planetary gear set 8 Control valve 9 Line pressure solenoid 10 Low clutch solenoid 11 2nd / 4th speed brake solenoid 12 High clutch solenoid 13 Low reverse brake Solenoid 14 Transmission controller 15 Throttle opening sensor 16 Turbine rotation sensor 17 Output rotation sensor 18 Inhibitor switch 19 Hydraulic switch 20 Line pressure oil passage 21 Manual valve 22 D range pressure oil passage 23 R range pressure oil passage 24 Pilot valve 25 Pilot pressure Oil passage 26 First pressure control valve 27 Low clutch pressure oil passage 28 Second pressure control valve 29 High clutch pressure oil passage 30 Third pressure control valve 31 2-4 Brake pressure oil passage 32 Fourth pressure control valve 33 Low reverse brake Pressure oil passage 34 Lock-up solenoid 35 spool signal pressure oil passage 36 spool valve L / C low clutch 2-4 / B 2-speed - fourth speed brake H / C high clutch LR / B low reverse brake R / C reverse clutch L / OWC low one-way clutch

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazunari Ohtake 1-1, Yoshiwara-cho, Fuji-shi, Fuji-shi, Shizuoka Prefecture F-term in JATCO TransTechnology Co., Ltd. 3J552 MA02 MA12 NA01 NB01 PA02 RA02 SA09 SA10 SA54 SB33 TA01 VA32Z VA37Z VA52W VA52Y VA76Y VB01Z VC03Z

Claims (3)

[Claims] A first friction element among a plurality of friction elements is fastened by an increase in operating oil pressure, and a second friction element is set after a set time by receiving a pressure signal related to the operating oil pressure of the first friction element. Is released by lowering the operating oil pressure, and a shift is performed by changing over the first and second friction elements. At the time of the change, after the end of the loss stroke of the first friction element is detected, the second In an automatic transmission in which the operating oil pressure related to the friction element is decreased at a set gradient and the operating oil pressure related to the first friction element is increased at a predetermined slope, the oil pressure when detecting the end of the loss stroke, A shift control device for an automatic transmission, wherein the shift pressure is set slightly larger than the actual operating oil pressure at the end of a loss stroke. 2. The automatic transmission according to claim 1, wherein an upper limit value of the hydraulic pressure at the time of detecting the end of the loss stroke is smaller than a sum of a working oil pressure at the end of the loss stroke and a predetermined value. Transmission control device. 3. The method according to claim 2, wherein the predetermined value is 50 kPa.
A shift control device for an automatic transmission, characterized by the following.