JPH10238620A - Gear shift control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of hammering noises of gears caused by polarity change of torque from negative to positive side during inertial phase in foot-release up-shifting. SOLUTION: In this transmission device, up-shifting from third to fourth speed is performed by releasing a forward clutch based on lowering of operation pressure P0 and fastening a band brake based on the rise of operation pressure Pc as a result that power-ON running is shifted to power-OFF running due to lowering of a throttle opening TVO. At the time of up-shifting, the fastening side operation pressure Pc is increased to a limited pressure Pc Lim immediately before fastening, followed by feedback-controlling to obtain a target gear ratio during inertial phase where a gear ratio is changed from the value before shifting to a shifting gear ratio, that is, the gear ratio gr is ranged between reference gear ratios gr1 and gr4 . On the other hand, the releasing side operation pressure P0 is a sum of a return spring pressure Portn and a specified pressure ΔP according to an input torque. An output shaft torque is kept as indicated by a solid line during the inertial phase. It is prevented from being switched to positive as indicated by a two-dot chain line.

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 appropriately performing a shift at the time of an upshift accompanying switching from power-on traveling to power-off traveling. .

[0002]

2. Description of the Related Art An automatic transmission is provided with a gear transmission system by selectively engaging a plurality of clutches, brakes, and other speed-changing friction elements by increasing hydraulic fluid pressure or releasing them by decreasing hydraulic fluid pressure. Is determined by determining the power transmission path (gear stage) of the vehicle and switching the friction element that operates. Therefore, in an automatic transmission, there is a shift that is performed by changing the friction element in a disengaged state while simultaneously releasing the friction element in the engaged state by lowering the hydraulic fluid pressure and engaging the friction element in the released state by increasing the hydraulic fluid pressure. I do.

[0003] In the following description, the friction element to be switched from the engaged state to the released state during the gear shift is referred to as a release-side friction element, the hydraulic fluid thereof is referred to as a release-side hydraulic pressure, and the friction to be switched from the released state to the engaged state. The element is referred to as a fastening-side friction element, and its hydraulic pressure is referred to as a fastening-side hydraulic pressure.

[0004] At the time of such a shift, it is required to switch the disengagement-side friction element and the engagement-side friction element at an appropriate timing, so that the shift shock is likely to be large, and therefore the changeover of the friction element is performed under fine control. Must be done in Therefore, conventionally, for example, Japanese Unexamined Patent Application Publication No.
As described in Japanese Patent Publication No. 0, it has been proposed to perform feedback control of the hydraulic fluid pressure of the disengagement-side friction element so that the input shaft rotation change rate becomes a target value during gear shifting.

[0005]

Conventionally, the release-side hydraulic pressure control is performed while monitoring the input shaft rotation change rate.
As illustrated in FIG. 18, the amount of depression of the accelerator pedal is reduced from the state of depression of the accelerator pedal (the throttle opening TV of FIG. 18).
As a result, in the case of an upshift that is accompanied by a shift from power-on traveling to power-off traveling, the following problem arises.

That is, during such upshifting, the transmission output shaft torque is transmitted from the engine side to the wheel side from the positive torque transmitted from the engine side to the engine side (causing an engine brake state) due to the power-off traveling. Switch to negative torque. Incidentally, as is clear from the transmission output shaft torque change shown by the two-dot chain line in FIG. 18, the gear ratio g _r represented by the transmission output rotation ratio is changed to the post-shift value from the pre-shift value During the inertia phase, the transmission output shaft torque may temporarily protrude from the negative torque to the positive torque with the energy of the rotational inertia even during power-off traveling.

[0007] In this case, when the transmission output shaft torque changes polarity from negative torque to positive torque, or reversely in the direction of torque when the torque returns from positive torque to negative torque, a gear tapping sound occurs, Acceleration occurs, resulting in a reduction in shift quality. Conventionally, since the release-side hydraulic pressure is controlled while monitoring the rate of change of the input shaft rotation, these problems cannot be solved in any way.

A first object of the present invention is to propose a shift control device for an automatic transmission which can solve the above-mentioned problem.

It is an object of each of the second to sixth aspects of the present invention to solve the above-mentioned problem with simpler shift control.

A seventh object of the present invention is to prevent the above-mentioned speed change control from being uselessly performed under conditions that do not cause the problem to be solved by the present invention.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, a shift control device for an automatic transmission according to a first aspect of the present invention releases a friction element in an engaged state by lowering hydraulic fluid pressure and simultaneously releases a friction element in a released state. In an automatic transmission in which an upshift performed by increasing the hydraulic fluid pressure is performed, during the inertia phase of the upshift that accompanies switching from power-on traveling to power-off traveling, the transmission output torque is increased on the wheel side. From the negative polarity transmitted from the engine side to the engine side, the working fluid pressure of the release-side friction element to be released is controlled so that the polarity does not change to the positive polarity transmitted from the engine side to the wheel side. It is a feature.

According to a second aspect of the present invention, in the shift control device for an automatic transmission according to the first aspect, the hydraulic fluid pressure of the release-side friction element during the inertia phase is used to cause the release-side friction element to start slipping. The spring pressure is set to a value obtained by adding the spring equivalent pressure and a predetermined pressure.

A shift control apparatus for an automatic transmission according to a third aspect of the present invention is the automatic transmission control apparatus according to the second aspect, wherein the predetermined pressure is calculated by multiplying a transmission input torque by a coefficient.

According to a fourth aspect of the present invention, there is provided a shift control device for an automatic transmission according to the third aspect, wherein the frictional coefficient μ of the clutch plate, the number n of the clutch plates, and the operation when the release-side friction element is a wet multi-plate clutch. Using the hydraulic pressure receiving area A _p , the effective radius R _m , and the transmission input torque T _i , the coefficient α is determined by α∝T _i / 2 · μ · n · A _p · R _m . Things.

According to a fifth aspect of the present invention, in the shift control device for an automatic transmission according to the third aspect, the disengagement-side friction element is a band brake, and the band brake performs a braking action in a leading direction during the upshift. The friction coefficient μ of the band, the winding angle θ of the band, the winding diameter R of the band, the pressure receiving area A _S of the working fluid pressure, the base e of the natural logarithm, and the transmission input torque T _i are used to calculate the coefficient α.
To

(Equation 3) It is configured to be determined by

According to a sixth aspect of the present invention, in the transmission control apparatus for an automatic transmission according to the third aspect, the disengagement-side friction element is a band brake, and the band brake performs a braking action in a trailing direction during the upshift. The friction coefficient μ of the band, the winding angle θ of the band, the winding diameter R of the band, the pressure receiving area A _S of the working fluid pressure, the base e of the natural logarithm, and the transmission input torque T _i are used to calculate the coefficient α.
To

(Equation 4) It is configured to be determined by

According to a seventh aspect of the present invention, in the automatic transmission control apparatus according to any one of the first to sixth aspects, when the transmission output torque becomes positive during the inertia phase of the upshift, The hydraulic fluid pressure of the release-side friction element is reduced to a minimum pressure to completely release the hydraulic fluid.

[0018]

According to the first aspect of the present invention, the automatic transmission releases the friction element in the engaged state by lowering the hydraulic fluid pressure.
A corresponding upshift is performed by engaging the friction element in the released state by increasing the hydraulic fluid pressure.

When the upshift is accompanied by switching from power-on traveling to power-off traveling,
During the inertia phase of the upshift, the working fluid pressure of the disengagement-side friction element changes in polarity from the negative polarity in which the transmission output torque is transmitted from the wheel side to the engine side to the positive polarity in which the transmission output torque is transmitted from the engine side to the wheel side. Control not to do.

Therefore, during the torque phase of the upshift that accompanies the switching from the power-on traveling to the power-off traveling, the transmission output shaft torque temporarily protrudes from negative torque to positive torque with the energy corresponding to the rotational inertia. Such a situation can be reliably prevented, and during this torque phase, the direction of the transmission output shaft torque is switched, causing gear hitting noise, longitudinal acceleration, and the like, resulting in deterioration of shift quality. Such a phenomenon can be completely eliminated.

In the second aspect of the invention, when determining the hydraulic fluid pressure of the release-side friction element during the inertia phase for achieving this object, the return spring equivalent pressure required to cause the release-side friction element to start slipping. And the predetermined pressure are used as the hydraulic fluid pressure of the release-side friction element.

Therefore, according to the second aspect of the present invention, the operation and effect of the first aspect of the present invention can be more easily achieved only by adding the above predetermined pressure without finely controlling the hydraulic fluid pressure of the release-side friction element during the inertia phase. Can be achieved.

In the third aspect of the invention, the predetermined pressure in the second aspect of the invention is obtained by calculation by multiplying the transmission input torque by a coefficient, so that the operation and effect of the first aspect of the invention can be more easily achieved.

In the fourth invention, the coefficient α in the third invention is defined as follows: when the release-side friction element is a wet multi-plate clutch, the friction coefficient μ of the clutch plate, the number n of the clutch plates,
Receiving area A _p of the hydraulic fluid pressure, effective radius R _m, and with a transmission input torque T _i, since the determined by _{ααT i / 2 · μ · n} · A p · R m, the release-side friction element Is a wet multi-plate clutch, the coefficient α in the third invention, and thus the predetermined pressure in the second invention, can be obtained by calculation,
The operation and effect of the first invention can be easily achieved.

According to a fifth aspect of the present invention, the coefficient α in the third aspect of the present invention is obtained by:
When the band brake performs a braking action in the leading direction at the time of the upshift, when the band has a friction coefficient μ, a band winding angle θ, a band winding diameter R, a hydraulic pressure receiving area A _S , a natural logarithm base e. , And the transmission input torque T _i ,

(Equation 5) Therefore, even when the release-side friction element is a band brake, which exerts a braking action in the leading direction during the upshift, the coefficient α in the third aspect of the invention, that is, the predetermined pressure in the second aspect of the invention is obtained by calculation. Therefore, the operation and effect of the first invention can be easily achieved.

According to a sixth aspect of the present invention, the coefficient α in the third aspect of the present invention is obtained by:
If this makes the braking action in Toreringu direction when the upshift, the friction coefficient of the band mu, angle winding band theta, winding diameter R of the band, the pressure receiving area A _S of the hydraulic fluid pressure, the base of the natural logarithm e, and shift Using the machine input torque T _i , the coefficient α is

(Equation 6) Thus, even when the release-side friction element is a band brake, which exerts a braking action in the trailing direction at the time of the upshift, the coefficient α in the third invention, that is, the predetermined pressure in the second invention is obtained by calculation. Therefore, the operation and effect of the first invention can be easily achieved.

In the seventh aspect of the present invention, when the transmission output torque becomes positive during the inertia phase of the upshift, the operating fluid pressure of the release-side friction element is reduced to the minimum pressure and completely released. In spite of the conditions that do not cause the problem to be solved by the present invention, it is possible to avoid the disadvantage that the above-described shift control is performed uselessly.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a control system of an automatic transmission provided with a shift control device according to one embodiment of the present invention, wherein 1 is an engine, 2 is a torque converter, 3 is an automatic transmission, and the engine rotation is a torque converter 2 Through the input shaft 4 of the automatic transmission.

The automatic transmission 3 is basically the same as that described in "RE4R01A Automatic Transmission Maintenance Manual" (A261C07) issued by Nissan Motor Co., Ltd. , 5 are provided with a front planetary gear set 6 and a rear planetary gear set 7 mounted thereon.

The forward clutch F / C, high clutch H / C, band brake B /
B, a low reverse brake LR / B, a low one-way clutch L / OWC, and a reverse clutch R / C, and selectively engaging these as indicated by a circle in FIG. And the reverse gear can be selected. In addition, low reverse brake LR
(○) regarding / B indicates that the engine is to be engaged at the first speed when engine braking is required.

In order to execute the selective operation (engagement) of the friction element, the control valve 8 of the automatic transmission 3 is controlled.
Include a duty solenoid 9 for a forward clutch F / C, a duty solenoid 10 for a high clutch H / C, a duty solenoid 11 for a band brake B / B, a duty solenoid 12 for a low reverse brake LR / B, and a river. The duty logic 13 for the scratch R / C is provided, and the duty of the operating oil pressure of the corresponding friction element is individually controlled by the duty solenoid 13 to realize the engagement logic shown in FIG. Transient control.

The duty control of the solenoids 9 to 13 is performed by a controller 14, which receives a signal from a throttle opening sensor 16 for detecting a throttle opening TVO of the engine 1 and an engine speed N.
_e , a signal from the engine rotation sensor 17 for detecting _e , and an input rotation speed N _i from the torque converter 2 to the automatic transmission 3.
A signal from an input rotation sensor 18 for detecting a signal from the output rotation sensor 19 for detecting a transmission output speed N _o, and a signal from an oil temperature sensor 20 for detecting a transmission working oil temperature T _OIL input.

In this embodiment, the released band brake B / B is engaged by increasing the hydraulic pressure, and the forward clutch F / C in the engaged state is released by decreasing the hydraulic pressure. The idea of the present invention is applied to the upshift shift from the third speed to the fourth speed to be performed,
For this reason, in particular, the hydraulic fluid pressure control portion of the forward clutch F / C and the band brake B / B extracted from FIG. 1 and shown in FIGS. 3 and 4, respectively, will be described in detail below.

FIG. 3 shows a hydraulic fluid pressure control circuit of the forward clutch F / C, which is a disengagement-side friction element to be changed from the engaged state to the disengaged state during the upshift from the third speed to the fourth speed. , A pressure regulating valve 22 is provided in an operating pressure circuit 21 of the forward clutch F / C.
The line pressure P _L is used as the base pressure, and the operating oil pressure P _o of the forward clutch F / C according to the increase of the control pressure in the chamber 22a.
From 0.

The control pressure in the chamber 22a of the pressure regulating valve 22 is determined by the corresponding solenoid 9.
The solenoid 9, the constant pilot pressure P _p that created the line pressure P _L under reduced pressure and source pressure, and supplies a control pressure according to the driving duty of the solenoid 9 in the chamber 22a.

FIG. 4 shows the hydraulic fluid pressure control circuit of the band brake B / B, which is the engagement-side friction element to be changed from the released state to the engaged state in the same upshift from the third speed to the fourth speed. , A pressure control valve 24 is provided in the operating pressure circuit 23 of the band brake B / B. The pressure control valve 24 uses the line pressure P _L as a base pressure, and controls the band brake B / B in response to an increase in the control pressure in the chamber 24a. It is assumed that the hydraulic pressure _Pc is increased from zero.

The control in the pressure regulating valve 24 in chamber 24a pressure, what determines by the solenoid 11 corresponding, the solenoid 11, the original pressure constant pilot pressure P _p that created the line pressure P _L in vacuo The control pressure according to the drive duty of the solenoid 11 is supplied to the chamber 24a.

The controller 14 shown in FIG. 1 executes a control program shown in FIG. 5 based on the above input information,
Particularly, the upshift from the third speed to the fourth speed is performed according to the time chart of FIG. FIG.
In step 31, the engine throttle opening TVO detected by the sensor 16, since the transmission output speed N _o detected by the sensor 19 (vehicle speed), based on the shift map will also to the driving conditions The desired preferred gear is searched for, and if the currently selected gear is the same as this preferred gear, there is no need for gear shifting, so control is terminated as it is, and if the current selected gear is different from this preferred gear, Step 3
In step 2, the shift to the preferred gear is performed.

The gear shifting in step 32 is performed from a power-on running state in which power is transmitted from the engine to the wheel side by depressing the accelerator pedal (a state in which the transmission output torque is positive), and a throttle opening degree by returning the accelerator pedal. TVO
As shown in FIG. 18, the power is transmitted from the wheel side to the engine side (in a state where the transmission output torque is negative and the engine brake is effective). Upshift to 4th gear (foot release 3 → 4)
In the case of an upshift, this is as shown in FIGS.

First, FIG. 6 shows the processing in the first stage in FIG. 18. In step 41 of FIG. 18, it is determined whether or not the release-from-three-to-four upshift command has been issued and this is the first time. I do. Step 4 if it is the first time
In 2, the control data used in the first stage is set.

The control data set in step 42 is as shown in FIG.
In the first stage, the engagement side friction element (band brake B /
B), the pre-charge pressure P _pr to be applied, the first stage control time t ₁ (see FIG. 18), and the operating oil pressure P _o of the disengagement-side friction element (forward clutch F / C) to be continuously reduced after the first stage. Lamp control time t
₂ Read (see Fig. 18).

Here, the control time t of the first stage
₁ is the time required for completing the loss stroke of the engagement-side friction element under the precharge command pressure _Ppr , and is set in advance, for example, for each transmission operating oil temperature T _OIL . Also, a time t ₂ for lowering the operating oil pressure _Po of the release-side friction element at the same gradient as the first stage after the first stage.
Is, when reducing an operating pressure P _o of the disengagement side frictional element, when an attempt to complete the short time in the reduction, such as the first stage control time t _1, rapid decrease in the release-side hydraulic pressure P _o too, since causing undershoot at the control end, predetermined as the time for preventing undershoot to be added to the first stage control time t _1.

Next, at step 52, the transmission input torque T _i is calculated. At the time of this calculation, first, as shown in FIG.
_e (torque converter input rotation speed) and transmission input shaft rotation speed (torque converter output rotation speed) _{Ni are used} to determine the torque converter speed ratio _et ( _et = _Ni / _Ne ). , based on a torque converter characteristic curves illustrating this speed ratio e _t in FIG. 17, seeking τ torque ratio t and the torque capacity coefficient of the torque converter, at step 63, using these turbine torque (transmission input torque ) T _i is calculated by calculation of T _i = τ · t · _Ne ² .

[0044] In step 53 of FIG. 7, the input torque T _i of the original at disengagement side frictional element (the forward clutch F / C) to slip without disengagement side required oil pressure P _Omin to keep the barely state (FIG. 18 see) as shown in Figure _{9, P omin = T i ·} k / 2nμA p R m ( where, k: the torque sharing rate of the forward clutch F / C, n: number of clutch plates, mu: friction coefficient of the clutch plate , a _p: pressure-receiving area of the disengagement side hydraulic pressure P _o, R _m: calculated by effective radius) of the clutch plate.

[0045] In step 54 of FIG. 7, was added disengagement side hydraulic pressure P _o from the line pressure P _L corresponding value, the fluid pressure d for the undershoot preventing disengagement side required oil pressure P _Omin as shown in FIG. 18 required to reduce to a pressure value _(P omin + d), the first ramp gradient Δ of the disengagement side hydraulic pressure P _o
P _o1 and [Delta] P _o1 = - is calculated by _{[P L} (P omin + d)] _{/ (t 1 + t 2)} ··· (1).

In step 43 of FIG. 6, based on the data set in step 42 as described above, the control of the engagement side operating oil pressure _Pc and the release side operating oil pressure _Po in the first stage is performed as follows. Do. In other words, as shown in FIG. 18, the engagement side operating oil pressure _Pc is instructed to the precharge pressure _Ppr to the solenoid 11 to quickly reduce the loss stroke of the engagement side friction element (band brake B / B). be completed, the disengagement side hydraulic pressure P _o is this, commands the solenoid 9 to is shown in Figure 18 reduces by one first ramp gradient [Delta] P _o1.

The processing in step 43 is the same as that in step 44
The timer TM incremented by t
18 until the first stage control time t ₁ is reached, and as shown in FIG.
→ First stage control time t from 4 upshift command
In _1, the release-side hydraulic fluid pressure command value P _o is reduced by a ramp of [Delta] P _o1, the engagement side hydraulic fluid pressure command value P _C is maintained to the precharge command pressure P _pr, loss stroke of the engagement side frictional element Can be theoretically completed at the end instant of the first stage control time t ₁ .

In the meantime, at step 45, the release side operating oil pressure P
_o time to determine that it has reduced to the required pressure P _Omin holds the required oil pressure P _Omin the disengagement side hydraulic pressure P _o in step 46, that the disengagement side hydraulic pressure P _o lower than required oil pressure P _Omin Not to be. If it is determined in step 47 that the timer TM indicates the first stage control time t ₁ , the timer TM is reset to 0 in step 48 so that the timer TM can be used for subsequent use. The control proceeds to the second stage in FIG.

The control of the second stage is intended such shown in FIG. 10, the timer TM is Δt increments incremented in step 71 after the transition to the second stage, as shown in a second stage control time t ₃ at Step 81 In steps 72 to 80 until it is determined that
The following shift control is performed as shown in FIG.

In step 73, which is selected when it is determined at step 72 that this is the first time after shifting to the second stage, data used for control in the second stage is set as shown in FIG. First, in step 91,
Return spring equivalent pressure P _{crtn of} engagement side friction element (band brake B / B), second stage control time t ₃ (see FIG. 18), engagement side friction element (band brake B / B)
Return spring equivalent pressure control time t ₄ for keeping the operating oil pressure P _c of the return spring equivalent pressure P _crtn ,
Already the first ramp gradient ΔP of the first ramp control time t _2, likewise the above-mentioned disengaging-side engaging element hydraulic pressure P _o of the disengagement side frictional element hydraulic pressure P _o in has been the precharge after
_o1, read second ramp gradient [Delta] P _o2 respective disengagement side frictional element hydraulic pressure P _o set it to the more gradual slope.

In step 92 of FIG. 11, the transmission input torque Ti at the time of entering the second stage is calculated in the same manner as described above with reference to FIG. 8, and in the next step 93, the transmission input torque T _i is calculated as described above with reference to FIG. Similarly, under the transmission input torque T _i , the release-side required hydraulic pressure P _omin for maintaining the release-side friction element (forward clutch F / C) in a state just before slipping is calculated.

Based on the control data set as described above, the shift control for the second stage is executed as follows after step 74 in FIG. Step 7
In steps 4 and 75, in step 74, the timer TM
Hydraulic pressure P _c of but until determining that now shows the course of the return spring equivalent pressure control time t ₄ from the transition to the second stage, the engagement side frictional element at step 75
To the return spring equivalent pressure P _crtn, after the timer TM determines in step 74 that the return spring equivalent pressure control time t ₄ has elapsed since the transition to the second stage, Step 75 is skipped and a command is _sent to the solenoid 11 which holds the operating oil pressure _Pc of the engagement-side friction element at the return spring equivalent pressure _Pcrtn as shown in FIG.

In steps 76 to 78, steps
At 76, the timer TM moves from the transition to the second stage.
First ramp control time t for release-side friction element_TwoShow the progress of
Released in step 77 until it is determined that
Operating oil pressure P of side friction element_oTo the first ramp gradient ΔP_o1At low
Command to solenoid 9 and
MA is used for the release side friction element from the transition to the second stage
First ramp control time t _TwoIt is judged that the progress of
After the setting, in step 78, the operation of the release side friction element is performed.
Dynamic hydraulic pressure P_oTo the second ramp gradient ΔP as shown in FIG.
_o2Command the solenoid 9 to lower
You.

In the meantime, at step 79, the release side operating oil pressure P
_If it is determined that _o has decreased to the required oil pressure P _omin corresponding to the transmission input torque T _i at the instant of the transition to the second stage obtained in step 93 of FIG.
The release-side hydraulic pressure P _o is held in the required oil pressure P _Omin at 0, so as not to lower than necessary oil pressure P _Omin disengagement side working oil pressure P _o.

In step 81 of FIG.
Is the second stage control time t from the transition to the second stage.
_When it is determined that the time has elapsed, the control proceeds to step 82, where the timer TM is reset to 0 to prepare for the next time, and then, in step 83, the processing of the third stage is started.

The processing of the third stage is as shown in FIG. 12. In step 111, the timer TM is incremented to measure the elapsed time since the entry into the third stage. 1 after entering the third stage
Step 12 selected by Step 112 only once
In FIG. 3, as shown in FIG. 13, the control data used in the stage, that is, the third stage control time t ₅ (see FIG. 18), the disengagement side friction element (forward clutch F
/ C feedback hydraulic pressure P _o of) (PID) proportional control constant K _p used in controlling, integral control constant K _i,
And a differential control constant K _d , a first ramp gradient ΔP _c1 used when increasing the operating oil pressure P _c of the engagement-side friction element (band brake B / B), and a first reference gear ratio g used for determining the start of the inertia phase. _r1 , an engagement-side limiting pressure _PcLim for keeping the engagement-side friction element (band brake B / B) in a state where it does not slip, and an operation for _starting to release the release-side friction element (forward clutch F / C). Set the release side return spring equivalent pressure P _{or tn} .

Here, the engagement-side limiting pressure P _cLim is determined based on the transmission input torque T _i at the start of the third stage determined as shown in FIG. determined by multiplying safety factor to the operation pressure of the brake B / B) (about 1.2), also disengagement side return spring equivalent pressure P _Ortn also going friction element from the transmission input torque T _i during the third stage starts (Forward clutch F / C) is determined as an operating pressure for starting to slip.

In step 114 of FIG.
Machine input / output rotation ratio N_i/ N_oGear ratio g_rIs calculated,
In step 115, the gear ratio g_rIs the first reference gear
Ratio g _r1Is determined to have decreased to
At 116, the timer TM enters the third stage
To the third stage control time t_FiveIs determined to indicate the progress of
Until step 117, the engagement-side friction element (the bump
Operating pressure P of brakes B / B)_cAs shown in FIG.
First ramp gradient ΔP_c1To raise.

In step 118, the operating pressure P of the engagement-side friction element (band brake B / B) is
_When it is determined that _c has exceeded the limit pressure _PcLim , step 1
The engagement side hydraulic pressure P _c of directing the limit pressure P _Clim at 19, so that the engagement side hydraulic pressure P _c is not to exceed the limit pressure P _Clim.

[0060] On the other hand, with respect to working pressure P _o of the disengagement side frictional element (the forward clutch F / C), to control this as follows. First, in step 120, the target gear ratio _gr0 is read, and then, in step 121, the target gear ratio _gr0 during the ramp-up of the engagement side operating oil pressure _Pc.
There the release-side hydraulic pressure P _o to be achieved, this gear ratio g _r, 1 times before the gear ratio g _r-1, the two previous gear ratio g _r-2,
And using the target gear ratio g _r0, further said control constants K _p, K _{i, P} using the _{K d o = P o + K} p (g r -g r-1) + K i (g r0 -
g _r ) + K _d (g _r −2 g _{r −1} + g _r−2 ), which is commanded to the solenoid 9.

[0061] Then, as long as the release-side hydraulic pressure P _o in step 122 is determined to be higher than the return spring equivalent pressure P _Ortn, repeat the loop control returns to step 111, releasing side working oil pressure P _o in step 122 Is determined to be lower than the return spring equivalent pressure _Portn , at step 123
_{After making o} not lower than the return spring equivalent pressure _Portn , the control is returned to step 111 and the above loop is repeated.

[0062] By the above control, or it is determined that the gear ratio g _r decreases to the first reference gear ratio g _r1 in step 115 (the inertia phase start), or, in step 116, the timer TM is entered in the third stage after when it is determined that shows the course of the third stage control time t _5, control the advancing step 124 and 125, it resets the timer TM to 0, the control proceeds to the fourth stage.

The fourth stage is as shown in FIG. 14. In step 131, the timer TM is incremented to measure the elapsed time since entering the fourth stage. In step 133, which is selected only once in step 132 after entering the fourth stage, control data used in that stage is set as shown in FIG.

First, the engagement side friction element (band brake B
/ B feeds back the working oil pressure P _c of) (PID) proportional control constant K _p used in controlling, integral control constant K _i,
And it reads the differential control constants K _d, and then reads the control time t ₆ (see FIG. 18) of the fourth stage, is read sequentially smaller second reference gear ratio g _r2 ~ fourth reference gear ratio g _r4, the engagement side friction The second ramp gradient Δ used when increasing the operating oil pressure P _c of the element (band brake B / B)
_Pc2 is read, and the return spring equivalent pressure _Portn of the release-side friction element (forward clutch F / C) is calculated,
A predetermined pressure ΔP to be added to the release side return spring equivalent pressure _Portn is calculated so as to achieve the object of the present invention. Here, the release side return spring equivalent pressure P
It goes without saying that _{ortn is} also determined based on the transmission input torque at the time of entering the fourth stage, which is obtained in the same manner as in FIG.

The release side return spring equivalent pressure P
The calculation of the predetermined pressure ΔP to be added to _ortn is performed as shown in FIG. That is, in step 141, the engine speed _Ne and the transmission input speed _Ni are read, and then, in step 142, based on these, the transmission input torque T _i at the time of entering the fourth stage is calculated based on FIG.
Is calculated.

[0066] At step 143, the the transmission input torque T _i, disengagement side frictional element (the forward clutch F /
And the friction coefficient of the clutch plate μ according to C), and the number n of the clutch plate, a pressure receiving area A _p of the hydraulic fluid pressure P _o, the effective radius R
by using the _{m, (T i / 2 ·} μ · n · A p · R m) to seek, this is multiplied by a proportionality constant to determine the α coefficient for determining the predetermined pressure [Delta] P. That is, the coefficient α is α∝T _i / 2μ
-Define as n · A _p · R _m . And step 14
At 4, the predetermined pressure ΔP is calculated by multiplying the transmission input torque T _i by a coefficient α.

[0067] In step 134 of FIG. 14 calculates the gear ratio g _r is a transmission input and output rotational speed ratio (N _i / N _o), in step 135, the gear ratio g _r is 3 greater than the reference gear ratio g _r3, inter judged to be greater than the second reference gear ratio g _r2 in step 137, to indicate the working oil pressure P _c of the engagement side frictional element (the band brake B / B) in FIG. 18 At the second ramp gradient ΔP _c2 . However, in the meantime step 138,129, the working oil pressure P _c of the engagement side frictional element (the band brake B / B), not to exceed the limit pressure P _Clim obtained in FIG.

[0068] After the gear ratio g _r is determined to have dropped to a second reference gear ratio g _r2 in step 136, advances the control to step 139, the engagement side friction element as thereafter shown in FIG. 18 (the band brake B / B) operating hydraulic pressure _Pc to limit pressure P
_Keep in _cLim . Momentary and the gear ratio g _r is determined to have decreased to a third reference gear ratio g _r3 in step 135, control proceeds to step 140, where for the gear ratio g _r is reduced smoothly as shown in FIG. 18 The target gear ratio _{gr0 of} is read.

Next, at step 141, the target
Gear ratio g_r0To achieve the engagement side working oil pressure P_cAnd now
Gear ratio g_rGear ratio g before_r-1The previous gear
Ratio g _r-2, And target gear ratio g_r0And the above
Constant K_p, K_i, K_dWith P_c= P_c+ K_p(G_r-G_r-1) + K_i(G_r0−
g_r) + K_d(G_r-2g_r-1+ G_r-2), And instructs the solenoid 11.

[0070] While controlling the engagement side hydraulic pressure P _c as described above, in the step 142 to 144 is controlled to as follows disengagement side working oil pressure P _o. That is, step 1
At 42, the transmission input torque T _i (the same applies to the transmission output torque) is transmitted from the wheel side to the engine side (causing an engine braking state) or negatively transmitted from the engine side to the wheel side. Is determined. In step 143 if a negative torque, and as shown in FIG. 18, Wachi the release-side hydraulic pressure P _o return spring equivalent pressure P _Ortn and predetermined pressure ΔP of the (P
_ortn + ΔP).

[0071] According to the control of the disengagement side hydraulic pressure P _o in the take inertia phase, since to define a predetermined pressure ΔP as described above, the transmission output torque remains negative polarity as indicated by the solid line in FIG. 18 The polarity is maintained, and the polarity does not change from negative to positive. Therefore, during the torque phase of the upshift that accompanies the switch from the power-on traveling to the power-off traveling, a situation in which the transmission output shaft torque temporarily projects from negative torque to positive torque with the energy corresponding to the rotational inertia. During the torque phase, the direction of the transmission output shaft torque is switched, causing gear tapping noise, longitudinal acceleration, etc. Can be completely eliminated.

If it is determined in step 142 that the transmission input torque T _i (and the transmission output torque is the same) has a positive polarity, the condition does not cause the problem to be solved by the present invention. At 144, the disengagement side operating oil pressure _Po is drained to zero to completely disengage the disengagement side friction element (forward clutch F / C).
Therefore, it is possible to avoid the disadvantage that the release-side operating pressure control is uselessly performed even under the condition that does not cause the problem to be solved by the present invention.

At step 145 in FIG. 14, the gear ratio g
_rIs the fourth reference gear ratio g_r4Until it is determined that
Repeat the above loop, but with the gear ratio g_rIs the fourth reference gear
Ratio g _r4After it has decreased to
Then, as shown in FIG._oThe drain
And the engagement side hydraulic pressure P_cIs the highest
Line pressure P_LTo the same value as Step 146 processing
Means that the timer TM is in the fourth stage in step 147
4th stage control time t after entering₆As shown
It repeats until it judges that it became the 4th stage control time
t₆When the time has elapsed, in step 148, the timer
TM is reset to 0, and the shift is ended.

In the above embodiment, the case where the release-side friction element is the forward clutch F / C has been described. However, the release-side friction element is the band brake B / B.
At the time of a foot release upshift, in which the band brake performs a braking action in the leading direction, the coefficient α is used.
The coefficient of friction bands mu, angle winding band theta, winding diameter R of the band, the pressure receiving area A _S of the hydraulic fluid pressure, with a base of natural logarithms e, and the transmission input torque T _i,

(Equation 7) The predetermined pressure ΔP is represented by ΔP =
You can achieve the same effect by calculating the alpha · T _i.

Further, the release side friction element is a band brake B
/ B, and the above-mentioned coefficient α is used at the time of a foot-release upshift in which the band brake performs a braking action in the trailing direction.

(Equation 8) The predetermined pressure ΔP is represented by ΔP =
You can achieve the same effect by calculating the alpha · T _i.

[Brief description of the drawings]

FIG. 1 is a control system diagram of an automatic transmission including a shift control device according to an embodiment of the present invention.

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

FIG. 3 is a circuit diagram showing an operating pressure control circuit of a forward clutch which becomes a disengagement-side friction element during an upshift from a third speed to a fourth speed in the automatic transmission.

FIG. 4 is a circuit diagram showing an operating pressure control circuit of a band brake serving as an engagement-side friction element during an upshift from a third speed to a fourth speed in the automatic transmission.

FIG. 5 is a flowchart showing a main routine of a shift determination program to be executed by a controller in the embodiment.

FIG. 6 is a flowchart showing a subroutine relating to a first stage of shift control to be executed when a 3 → 4 upshift shift command is issued in the shift determination.

FIG. 7 is a flowchart showing a control data setting routine used in the first stage.

FIG. 8 is a flowchart showing a subroutine for calculating a transmission input torque among control data used in the first stage.

FIG. 9 is a flowchart showing a subroutine for calculating a release-side engagement required oil pressure among control data used in the first stage.

FIG. 10 is a flowchart showing a subroutine relating to a second stage of shift control to be executed when the same 3 → 4 upshift shift command is issued.

FIG. 11 is a flowchart showing a control data setting routine used in the second stage.

FIG. 12 is a flowchart showing a subroutine relating to a third stage of shift control to be executed when the 3 → 4 upshift shift command is issued.

FIG. 13 is a flowchart illustrating a control data setting routine used in the third stage.

FIG. 14 is a flowchart showing a subroutine relating to a fourth stage of shift control to be executed when the same 3 → 4 upshift shift command is issued.

FIG. 15 is a flowchart showing a control data setting routine used in the fourth stage.

FIG. 16 is a flowchart for calculating a predetermined pressure to be added to the release-side return spring equivalent pressure, out of the control data used in the fourth stage.

FIG. 17 is a performance diagram of a torque converter used when calculating a transmission input torque.

FIG. 18 is an operation time chart of the foot release 3 → 4 upshift transmission control according to FIGS. 6 to 16;

[Explanation of symbols]

 1 Engine 2 Torque converter 3 Automatic transmission 4 Input shaft 5 Output shaft 6 Front planetary gear set 7 Rear planetary gear set 8 Control valve 9 Duty solenoid 10 Duty solenoid 11 Duty solenoid 12 Duty solenoid 13 Duty solenoid 14 Controller 16 Throttle opening sensor 17 Engine Rotation sensor 18 Input rotation sensor 19 Output rotation sensor 20 Oil temperature sensor 22 Pressure regulator 24 Pressure regulator F / C Forward clutch (disengagement friction element) B / B Band brake (engagement friction element) H / C High clutch LR / B Low reverse brake R / C reverse clutch

Claims (7)

[Claims] 1. An automatic transmission in which an upshift is performed by releasing a friction element in an engaged state by lowering hydraulic fluid pressure and simultaneously engaging the released friction element by increasing hydraulic fluid pressure. During the inertia phase of the upshift with the switch from power-on traveling to power-off traveling, the transmission output torque is transmitted from the wheel side to the engine side from the negative polarity,
Conversely, the shift control of the automatic transmission is characterized in that the working fluid pressure of the release-side friction element to be released is controlled so that the polarity does not change to the positive polarity transmitted from the engine side to the wheel side. apparatus. 2. The hydraulic pressure of the release-side friction element during an inertia phase is determined by adding a pressure equivalent to a return spring required to cause the release-side friction element to start slipping and a predetermined pressure. A shift control device for an automatic transmission, wherein the shift control device is configured to set the value to a predetermined value. 3. The shift control device for an automatic transmission according to claim 2, wherein the predetermined pressure is obtained by calculation by multiplying a transmission input torque by a coefficient. 4. The clutch according to claim 3, wherein, when the release-side friction element is a wet multi-plate clutch, the friction coefficient μ of the clutch plate, the number n of the clutch plates, the pressure receiving area A _p of the hydraulic fluid pressure, and the effective radius R _m. , and using the transmission input torque T _i, the coefficient alpha, the shift control device for an automatic transmission which is characterized by being configured to determine by _{ααT i / 2 · μ · n} · a p · R m . 5. The band according to claim 3, wherein the release-side friction element is a band brake, and when the band brake performs a braking action in a leading direction during the upshift, a band friction coefficient μ and a band winding angle θ. ,
Using the winding diameter R of the band, the pressure receiving area A _S of the hydraulic fluid pressure, the base of the natural logarithm e, and the transmission input torque T _i, the coefficient alpha, Equation 1] A shift control device for an automatic transmission, wherein the shift control device is configured to be determined by: 6. The band according to claim 3, wherein the release-side friction element is a band brake, and when the band brake performs a braking action in a trailing direction at the time of the upshift, a friction coefficient μ of the band and a winding angle θ of the band. ,
Using the winding diameter R of the band, the pressure receiving area A _S of the working fluid pressure, the base e of the natural logarithm, and the transmission input torque T _i , the coefficient α is calculated as follows: A shift control device for an automatic transmission, wherein the shift control device is configured to be determined by: 7. The hydraulic pressure of the disengagement-side friction element according to claim 1, wherein when the transmission output torque becomes positive during the inertia phase of the upshift, the hydraulic pressure of the release-side friction element is reduced to a minimum pressure. A shift control device for an automatic transmission, wherein the shift control device is configured to be lowered and completely released.