JPH05209680A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To enhance the responsiveness of oil pressure reduction when a friction fastening element is released and improve the following property of hydraulic feedback control at the time of a simultaneous shift of both of a main transmission and an auxiliary transmission. CONSTITUTION:At the time of a simultaneous shift of both transmissions in an automatic transmission AT having a main transmission 3 and an auxiliary transmission 4, the gear ratio progress of both transmissions is determined in real time, the oil pressure of the clutch of the auxiliary transmission 4 is feedback-controlled to follow the shift progress target value, the shift period is divided into multiple control segments ZF, the safety factor S for setting the oil pressure of the clutch under feedback control is changed small in the control segments 1, 2 where the shift is practically made, thus the responsiveness of oil pressure reduction is increased, and the following property of hydraulic feedback control is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission, and more particularly to a hydraulic pressure drop response for opening a friction engagement element during a main / sub simultaneous shift in an automatic transmission having both a main and a sub transmission. Related to the one that raised.

[0002]

2. Description of the Related Art Recently, an automatic transmission for an automobile has been proposed, which has a main transmission and a sub-transmission connected to the main transmission and realizes five forward speeds and one reverse speed. It is being converted. In the automatic transmission including the main transmission and the auxiliary transmission, it is very difficult to control the shift when the main transmission and the auxiliary transmission are switched at the same time. A shift shock occurs unless the engagement pressure and the release pressure are properly controlled. Japanese Unexamined Patent Publication No. 60-4950 discloses a technique for preventing a shift shock by causing the main transmission to start shifting before the sub-transmission, and at the end of shifting, synchronizing the main transmission and the sub-transmission. It is disclosed. The applicant of the present application, when simultaneously switching the main transmission and the auxiliary transmission, based on the gear ratio advance of the main transmission and the gear ratio advance of the auxiliary transmission, so that a predetermined target gear ratio advance, A control device for an automatic transmission that feedback-controls the hydraulic pressure of a friction engagement element is under development.

Conventionally, the engagement pressure of a friction engagement element of an automatic transmission is generally set to a total pressure of a hydraulic pressure corresponding to the spring set load of the element and a torque base oil pressure based on the torque acting on the element. It is set by multiplying by a safety factor (for example, 1.2). Then, there is a case where one of the two frictional engagement elements is opened while the other is engaged, such as during a main / sub-simultaneous gear shift. In such a case, the opening hydraulic pressure and the engaging hydraulic pressure are basically the same as above. Is set.

[0004]

In the case where one of the two friction engagement elements is opened while the other is engaged, such as during the main / sub simultaneous shift, hydraulic pressure is required by multiplying the safety factor as described above. Since the hydraulic pressure is set higher than the above, there is a problem that the response of the hydraulic pressure reduction in the opening side frictional engagement element is delayed, and as a result, the followability of the feedback control of the hydraulic pressure is reduced. The technique of Japanese Patent Laid-Open No. 62-4950 relates to the shift timing of the main transmission and the shift timing of the auxiliary transmission, and does not solve the above problems.
It is an object of the present invention to provide a control device for an automatic transmission that can improve the response of a decrease in hydraulic pressure and improve the followability of hydraulic feedback control.

[0005]

A control device for an automatic transmission according to a first aspect of the present invention is an automatic transmission comprising a main transmission and an auxiliary transmission connected to the main transmission, the main transmission and the auxiliary transmission. And feedback control for feedback control so that the actual shift progress state follows a preset target value of the shift progress state during simultaneous shift, and the feedback control control after the shift command during the simultaneous shift. And a hydraulic pressure changing means for decreasing the hydraulic pressure by changing the safety factor in the hydraulic pressure setting of the target frictional engagement element to a small value.

A control device for an automatic transmission according to claim 2 is
The apparatus according to claim 1, wherein the shift progressing state is a gear ratio advance of the main transmission and a gear ratio advance of the auxiliary transmission.

A control device for an automatic transmission according to claim 3 is
The apparatus of claim 2, wherein the feedback means is
In addition to the period in which the both gear ratio advancement changes, the feedback control is performed during a period in which the safety coefficient is changed to a small value.

A control device for an automatic transmission according to claim 4 is
The apparatus according to claim 2 is characterized in that the hydraulic pressure changing means is configured to restore the safety coefficient to the original value when the both gear ratio advance reaches 100%.

A control device for an automatic transmission according to claim 5 is:
The device of claim 4, wherein the feedback means is
It is characterized in that the feedback control is performed for a predetermined period after the safety factor is restored.

[0010]

In the automatic transmission control device according to the present invention, the feedback means is arranged so that the actual shift progress state during the simultaneous shift in which the main transmission and the sub transmission are simultaneously switched,
Feedback control is performed so as to follow a preset target value of the shift progressing state, and the hydraulic pressure changing means reduces the safety factor in the hydraulic pressure setting of the friction engagement element to be controlled by the feedback control after the shift command during the simultaneous shift. Change to reduce oil pressure. Therefore, at the time of main / sub simultaneous shift,
By making the actual shift progressing state follow the target value of the shift progressing state, it is possible to suppress the shift shock, promote the hydraulic pressure drop in the frictional engagement element to be disengaged, and improve the followability of the feedback control.

In the automatic transmission control device according to the second aspect of the present invention, the same operation as that of the first aspect can be obtained, and the progress state of the shift is determined by the gear ratio advance of the main transmission and the gear ratio advance of the auxiliary transmission. Therefore, it is possible to appropriately control the shift progressing states of the main and auxiliary transmissions so as to follow the target value.

In the automatic transmission control device according to the third aspect of the present invention, the same effect as that of the second aspect can be obtained, and the feedback means sets the safety factor to the value other than the period in which the both gear ratio advancement changes. Since the feedback control is performed even during the period during which the friction coefficient is changed to a small value, it is possible to compensate for the slip of the friction engagement element due to the decrease in hydraulic pressure during the safety coefficient change period.

In the automatic transmission control device according to the fourth aspect of the present invention, the same operation as that of the second aspect can be obtained, and the hydraulic pressure changing means has the safety factor when the both gear ratio advance reaches 100%. Is restored to the original value, it is possible to prevent the friction engagement element from slipping due to a decrease in hydraulic pressure caused by a change in the safety coefficient at the time point transition.

In the automatic transmission control device according to a fifth aspect of the present invention, the same operation as that of the fourth aspect can be obtained, and the feedback means also performs feedback control during a predetermined period after the safety factor is restored. It is possible to stabilize the hydraulic control in a predetermined period after returning.

[0015]

As described in the above section, the present invention provides the following effects. According to the control device for the automatic transmission according to claim 1, feedback means,
By providing the hydraulic pressure changing means, the actual shift progressing state is made to follow the target value of the shift progressing state at the time of the main / sub-simultaneous shifting, thereby suppressing the shift shock and reducing the hydraulic pressure in the friction engagement element to be disengaged. It is possible to enhance the followability of the feedback control.

According to the control device of the automatic transmission of the second aspect, the same effect as that of the first aspect can be obtained, and the progress state of the shift is determined by the gear ratio advance of the main transmission and the gear ratio of the auxiliary transmission. Since it is the degree of progress, it is possible to appropriately control the shift progressing states of the main and auxiliary transmissions so as to follow the target value.

According to the automatic transmission control device of the third aspect, the same effect as that of the second aspect can be obtained, and the safety factor is provided in addition to the period during which the both gear ratio advance is changed by the feedback means. By performing feedback control even during the period in which the value is changed to a small value, it is possible to compensate for the slip of the friction engagement element due to the decrease in hydraulic pressure during the period for changing the safety coefficient.

According to the automatic transmission control device of the fourth aspect, the same effect as that of the second aspect can be obtained, and the safety coefficient is returned to the original value when the both gear ratio advance reaches 100%. By returning it, it is possible to prevent the friction engagement element from slipping due to a decrease in hydraulic pressure caused by a change in the safety coefficient at the time point transition.

According to the automatic transmission control device of the fifth aspect, the same effect as that of the fourth aspect can be obtained, and further, the feedback control allows the feedback control even during a predetermined period after the safety coefficient is restored. The hydraulic control can be stabilized in a predetermined period after the return.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the output of the engine 1 is
It is transmitted to the drive wheels via an automatic transmission AT including a torque converter 2, a main transmission 3, and an auxiliary transmission 4. As shown in FIG. 2, the torque converter 2 includes a pump 20 coupled to the engine output shaft 1a, a turbine 21 arranged to face the pump 20, a pump 20 and a turbine 21.
And a stator 22 disposed therebetween. The stator 22 is configured to rotate on a fixed shaft 24 integrated with the case 5 of the automatic transmission AT via a one-way clutch 23. The one-way clutch 23 allows the stator 22 to rotate in the same direction as the pump 20, and prohibits rotation in the opposite direction.

The turbine 21 includes a torque converter 2
The output shaft 2a of the pump 20 is connected to the output shaft 2a of the pump 20.
A lockup clutch 25 is provided between and. The lockup clutch 25 is used for the torque converter 2
The hydraulic pressure of the hydraulic oil circulating inside constantly urges the clutch in the clutch engagement direction (lock-up direction), and at the same time it is held in the open state by the opening hydraulic pressure supplied from the outside. By draining this opening hydraulic pressure, the engine output The shaft 1a and the converter output shaft 2a are configured so as to be locked up in a direct connection.

Explaining the main transmission 3, the main transmission 3 includes a front stage planetary gear mechanism 3A and a rear stage planetary gear mechanism 3.
The front planetary gear mechanism 3A includes three gear elements of a sun gear 32, a pinion gear 31, and a ring gear 30 and a planetary carrier 34. The rear planetary gear mechanism 3B includes a sun gear 37 and a pinion gear. Three
6 and ring gear 35, and three planetary carriers 38. The carrier 34 and the ring gear 35 are coupled to each other, the ring gear 30 and the carrier 38 are coupled to each other, and the carrier 38 is coupled to the output shaft 3 a of the main transmission 3.

The converter output shaft 2a is connected to the sun gear 32 through the first clutch K1 and is connected to the second gear.
It is coupled to the sun gear 37 via the clutch K2.
The main transmission 3 includes three brakes fixed to a case 5, a first brake B1 (coast brake), and a second brake B1.
Brake B2 (coast brake) and third brake B
And a brake B1, which is a friction engagement element,
It is configured so that it is possible to achieve three forward speeds and one reverse speed by combining the engaged / released states of B2, B3 and clutches K1, K2. In addition to these, one-way clutches OWC1, OWC2 are also provided. ..

The sub-transmission 4 will be described. The sub-transmission 5 is composed of a planetary gear mechanism including three gear elements of a sun gear 40, a pinion gear 41 and a ring gear 42, and a planetary carrier 43. The ring gear 42 is a sub gear. The transmission 4 is connected to an input shaft 4a, the input shaft 4a is connected to an output shaft 3a of the main transmission 3 via a gear 44, and the carrier 43 is connected to an output shaft 4b of the sub transmission 4. .. The auxiliary transmission 4 is a brake B fixed to the case 5.
0, the sun gear 40 and the ring gear 42 are connected via a clutch K0, and a high speed stage (H) and a low speed stage (L) are obtained by a combination of a brake B0, which is a friction engagement element, and an engaged / released state of the clutch K0. And one-way clutch OWC0
Is also provided.

The automatic transmission AT has brakes B1 and B.
2, B3, B0 and clutches K1, K2, K0 are combined as shown in FIG.
It is possible to achieve a shift mode of 5 forward gears in addition to 1 reverse gear, and in the figure, a circle indicates a fastening operation. In addition, the above-mentioned five forward gear shift modes and the gear shift stages of the main transmission 3 and the auxiliary transmission 4,
The relationship with the gear ratio is as shown in FIG. 4, for example.

Next, the structure of the hydraulic circuit of the automatic transmission AT will be described. As shown in FIGS. 5 and 6, the line pressure P _L generated by the oil pump (not shown) is supplied from the line pressure oil passage 57 to the manual valve 50.
The manual valve 50 is connected to a shift lever, and by operating the shift lever, the neutral position (N), the parking position (P), the reverse position (R),
It is possible to switch to the drive position (D), and the drain pressure, drain pressure, R range pressure, D range pressure corresponding to these positions (however, the range pressure itself is equal to the line pressure P _L ) Each is configured to supply to the corresponding port.

Explaining the hydraulic system of the brakes B1, B2, B3 and the clutches K1, K2, which are the friction engagement elements of the main transmission 3, the three shift valves 51, 52, 53, as shown in FIG. Two pressure control valves 5
4, 55 are provided, and each shift valve 51, 52, 5
In Fig. 3, four lands are formed on the spool, the spool is biased to the left by a spring 58, and the oil chamber 56 at the left end is an ON / OFF type solenoid valve SOL A,
The line pressure P _L is supplied via SOL B and SOL C, and when these solenoid valves are ON, the hydraulic pressure in the oil chamber 56 is drained, and the shift valves 51, 52, 53 are located at the positions shown in the upper half of each of them. Again, these solenoid valves are OFF
At this time, the line pressure P _L is supplied to the oil chamber 56 and the positions are shown in the lower half portions of the respective lines.

The brake B1 has a D range pressure oil passage 6
From 0, shift valve 52, oil passage 61, shift valve 5
3. The D range pressure can be supplied via the oil passage 62. From the D range pressure oil passage 60 to the brake B2, the shift valve 52, the oil passage 64, the shift valve 51, the oil passage 65,
The D range pressure can be supplied through the shift valve 53 and the oil passage 66, and the brake B2 is connected from the R range pressure oil passage 68 to the shift valve 51, the oil passage 69, the shift valve 53, and the oil passage 66. The R range pressure can be supplied via this.
From the D range pressure oil passage 60 to the brake B3, the shift valve 51, the oil passage 70, the pressure control valve 55, the oil passage 7 are provided.
It is possible to supply the D range pressure via 1. From the line pressure oil passage 57 to the shift valve 52,
The line pressure P _L can be supplied via the oil passage 72, the shift valve 53, the oil passage 73, the pressure control valve 54, and the oil passage 74. From the D range pressure oil passage 60 to the clutch K2,
The D range pressure can be supplied via the oil passage 75. However,
In the figure, reference numerals 77 and 78 are orifices, and x is a drain port.

Further, accumulators 63, 67 and 76 for receiving the modulator pressure P _M corresponding to the engine torque are connected to the oil passages 62, 66 and 75, respectively.
In each of the pressure control valves 54 and 55, the spool has two lands, and the spool has a spring 80.
The oil chamber 82 at the left end is connected to the output port 84 via an oil passage 85 having an orifice 83, and a Red pressure (constant pressure) is linearly applied to the oil chamber 81 containing the spring 80. The control pressure P _C regulated by the solenoid valve 86 is supplied through the oil passage 87, and the hydraulic pressure of the output port 84 (the brake B3 and the clutch K1 is supplied by the control pressure P _C.
It is configured to control the hydraulic pressure supplied to). However, the pressure control valves 54 and 55 supply the pressure-controlled hydraulic pressure to the output port 84 when the hydraulic pressure is supplied to the respective input ports, and the output port 84 when the hydraulic pressure of the respective input ports is drained. The hydraulic pressure is also configured to drain.

The hydraulic system of the brake B0 and the clutch K0 which are the friction engagement elements of the auxiliary transmission 4 will be described.
As shown in FIG. 6, the shift valves 51, 52, 5
Two shift valves 90 and 91 having substantially the same structure as those of No. 3 are provided. In each of the shift valves 90 and 91, the spool is biased to the left by a spring 92, the spring accommodating chamber is drained, and the oil chamber at the left end is drained. ON / O for 93
The line pressure P _L can be supplied via FF type solenoid valves SOL D and SOL E.

A line pressure oil passage 57 is connected to the brake B0.
From the shift valve 90, oil passage 94, shift valve 9
1. The line pressure P _L can be supplied via the oil passage 95.
The line pressure P _L can be supplied to the clutch K0 from the line pressure oil passage 57 via the shift valve 90, the oil passage 97, the shift valve 91, the oil passage 98, and the oil passage 99. However, when the solenoid valves SOL D and E are both turned ON, the clutch K0 is provided with the line pressure oil passage 57, the shift valve 90, the oil passage 97, the shift valve 91, and the linear solenoid valve 100. The hydraulic pressure regulated by the linear solenoid valve 100 can be supplied via the passage 101 and the oil passage 99, and by turning on only the solenoid valve SOL D, the hydraulic pressure of the clutch K0 is drained via the oil passage 101. It is possible.

In the figure, reference numerals 102, 103 and 104 are orifices, x is a drain port, and an accumulator 96 for receiving the modulator pressure P _M is connected to the oil passage 95. A range and a shift stage relating to the automatic transmission AT, shift valves 51, 52, 53,
The relationship between the positions of 90 and 91, that is, the ON / OFF solenoid patterns of the solenoid valves SOL A to SOL E and the engagement patterns of the friction engagement elements (K1, K2, B1, B2, B3, K0, B0) are shown in FIG. It is as shown in FIG.

Next, a control system for controlling the automatic transmission AT will be described. As shown in FIG. 8, to the control unit 120 that controls the automatic transmission AT, the detection signal of the first sensor 110 that detects the rotation speed of the turbine output shaft 2a and the output of the main transmission 3 are input signals. The detection signal of the second sensor 111 that detects the rotation speed of the shaft 3a, the detection signal of the third sensor 112 that detects the rotation speed of the output shaft 4b of the auxiliary transmission 4, and the shift lever 113.
A shift signal corresponding to each range detected by a plurality of switches provided in the engine, a throttle opening signal TVO from a throttle opening sensor 114 for detecting an opening of a throttle valve of the engine 1, and a vehicle speed sensor 115 from a vehicle speed sensor 115. The vehicle speed signal SD and other detection signals from a brake switch or the like are input. The first to third sensors 110 to 112
Is, for example, an electromagnetic pickup type sensor and is shown in FIG.

A drive signal is output from the control unit 120 to the solenoid valves SOL A to SOL E and the linear solenoid valves 86, 100, 11 are output.
A drive pulse signal or a drive current is output to 6.
However, the linear solenoid valve 116 is for adjusting the modulator pressure. The control unit 120 is an A that performs A / D conversion of an input signal as needed.
A / D converter, a plurality of waveform shaping circuits, an input / output interface, a microcomputer, a plurality of drive circuits, etc. are provided, and the ROM of the microcomputer includes:
A general shift map having vehicle speed and throttle opening as parameters, a control program for shift control based on various input signals and shift maps (however, including the solenoid pattern corresponding to the range and the shift stage), etc. It is input and stored in advance. However, it is assumed that the control program for the shift control includes shift control, which will be described later.

Here, the shift control peculiar to the present application will be described. The shift control of this embodiment is performed by the main transmission 3 and the sub transmission 4
As a typical example of gear shifting in which the and
This is an example of a case of automatically shifting to high speed. To explain the outline of this shift control, it is necessary to engage the brake B3 while releasing the clutch K0 of the auxiliary transmission 4 at the time of 2-3 shift, but in this shift control, the parameter of the shift progress state is basically used. , The gear ratio advance of the main transmission 3 and the auxiliary transmission 4 is used as a parameter, and 2
A target value M (see FIG. 14) for the shift progressing state for -3 shift is set in advance, and the gear ratio advance of both transmissions 3 and 4 is obtained in real time and feedback is provided so as to follow the target value M. The control controls the hydraulic pressure of the clutch K0 via the linear solenoid valve 100.

Then, the shift period of the 2-3 shift is divided into three clutch pressure control sections, and in the section where the shift is substantially executed, the safety coefficient for setting the clutch hydraulic pressure is changed to a small value. , The hydraulic pressure of the clutch K0 is promoted to improve the response of the hydraulic pressure release, and the followability of the feedback control is improved. The following 2-3
The shift control of the shift will be described with reference to FIGS. 9 to 16, but in the flowchart, reference symbols Si (i = 1, 2,
3 ...) shows each step, and the flowchart describes only the configuration of feedback control of the hydraulic pressure of the clutch K0 in the 2-3 shift, and control of switching of solenoid valves associated with the 2-3 shift. Since these are general controls, the description thereof is omitted.

As shown in the flow charts of FIGS. 9 to 12, when the control is started during the 2-3 shift, various signals detected by the sensors are read (S1), and then in S2, as shown in FIG. The illustrated clutch pressure control section determination processing is executed, then the base clutch pressure setting processing illustrated in FIG. 11 is executed in S3, the clutch pressure feedback control illustrated in FIG. 12 is executed in S4, and S4 to S1. Returning to, the control is repeatedly executed every predetermined time (for example, 10 msec). The main change and the sub change are the main transmission 3 and the sub transmission 4, respectively, and F / B is the feedback.

Next, the clutch pressure control section determination process will be described with reference to FIG. 10. It is determined whether or not the counter CN is zero (S10). Since it is initially zero, the process proceeds to S11 and the shift signal (2- (Corresponding to a command signal for three shifts) is reversed from OFF to ON, the control section flag ZF is set to "0" when OFF, the control section flag ZF is set to "0", and then 2-3 at S13. After the shift flag SF is reset, the process proceeds to S3. When the shift signal is input, the determination in S11 becomes Yes, the process proceeds to S14, the flag SF is set, and then the counter CN
Is set to a predetermined value T0 (S15), the section flag ZF is set to "1", and then the process proceeds to S3.

On the other hand, after the counter CN is once set as described above, the process proceeds from S10 to S17, the counter CN is decremented by one, and then it is determined whether or not the shift of the main transmission 3 is started. (S18). This determination is based on the gear ratio advance G of the main transmission 3 calculated in S40.
It is determined based on m or the main variable gear ratio. Main transmission 3
When the shift is started, the process proceeds from S18 to S19, the section flag ZF is set to "2", and after the shift of the main transmission 3 is started, the process proceeds from S18 to S20. S2
At 0, it is determined whether or not the shift of the main transmission 3 is completed. Before the shift is completed, the process shifts from S20 to S3, and after the shift is completed, the process proceeds from S20 to S21 and the section flag ZF is set to "3". Then, the process proceeds to S3. By the clutch pressure control section determination processing as described above, the control section is set in parallel with the progress of the shift as shown in FIG.

Next, the base clutch pressure setting control in S3 will be described with reference to FIG. First, it is determined whether the section flag ZF is 0 or 3 (S30), and ZF =
When it is 0 or 3, the safety coefficient S is set to 1.2 in S31, and thereafter, the process proceeds to S36 through S32 and S34. When ZF = 1, S30, S32, and S
34, it is determined Yes in S34, the process proceeds to S35, the safety coefficient S is read from the table F (CN) having the count value CN of the counter CN as a parameter,
Then, the process proceeds to S36. Although this table F (CN) is not shown in the figure, as shown in FIG.
The safety coefficient S gradually decreases linearly from 1.2 with the passage of, and the safety coefficient S is set to about 1.0 at the end of the control section "1". The time required for the control section "1" is substantially constant, and since this shift control is repeated at predetermined time intervals, the count value CN at the end of the control section "1" becomes a substantially predetermined value. The table F (CN) can be set as described above.

On the other hand, when ZF = 2, S30 to S3
2, the result of the determination as to whether ZF = 2 is Yes, the process proceeds to S33, and the safety coefficient S is 1.
After being set to 0, the process proceeds to S36 via S34. In this way, the safety coefficient S set according to the control section in parallel with the progress of the shift is as shown in FIG. Next, in S36, the base clutch pressure BP is calculated as a value obtained by multiplying the torque base clutch pressure by a safety factor, and then the control shifts to S4. The torque base clutch pressure is set by a predetermined table or an arithmetic expression with the input torque to the auxiliary transmission 4 as a parameter, and the input torque is calculated based on the turbine torque and the main variable gear ratio, The turbine torque is calculated based on the throttle opening TVO of the engine.

Next, the clutch K executed by controlling the linear solenoid valve 100 with the solenoid valves SOL D and E set to ON and OFF, respectively.
The clutch pressure feedback control of 0 will be described with reference to FIG. First, at S40, the current main variable gear ratio advancement Gm and the current sub variable gear ratio advancement Gs are calculated. Here, the gear ratio advances Gm and Gs are parameters of the gear shift progressing states of the main and auxiliary transmissions 3 and 4, respectively, and a method of obtaining the gear ratio advances Gm will be described. The rotation speed of the converter output shaft 2a is N3i If the rotation speed of 3a is N3o,
The gear ratio Gr of the main transmission 3 is Gr = N3i / N3o, Gm
When the gear ratio of 0% (at the start of gear shift) and the gear ratio of 100% (at the end of gear shift) are Grs and Gre, respectively, and the current gear ratio is Gr, the current gear ratio progress Gm is Gm = (G
rs-Gr) / (Grs-Gre). The rotation speeds N3i and N3o can be obtained from the detection signals of the sensors 110 and 111, respectively. Further, the gear ratio advance Gs of the auxiliary transmission 4 can be obtained in the same manner, but the number of revolutions N
4i and N4o are the gear ratio of the gear 44 and the sensor 11 respectively.
It is determined from the detection signal of 1 and the detection signal of the sensor 112.

Next, in S41, the count value CN
Is determined to be non-zero, and if CN = 0 before the input of the shift signal or after the end of the control section 3, the process proceeds to S42, the clutch pressure CP is set to the base clutch pressure BP, and then the process proceeds to S51. To do. When the control section is "1", "2" or "3", CN = 0 is not satisfied, and the result of the determination in S41 is Yes. Therefore, the process proceeds to S43, and the sub-variation target gear ratio advancement Gst is calculated in S43. Here, in FIG.
As shown in the polygonal curve of the shift change target value M, the main variable gear ratio progress Gm is used as a parameter to set the sub variable target gear ratio progress Gst for 2-3 shifts in advance in the table Fg (Gm). Yes, in S43, the current main variable gear ratio advance degree Gm
The sub-variation target gear ratio advancement Gst corresponding to is calculated.

Next, in S44, it is determined whether or not the current sub-variable gear ratio advancement Gs is larger than the sub-variation target gear ratio advancement Gst. If Yes, the deviation α is calculated by the formula shown in S45, Next, in S46, the pressure increasing coefficient KI
Is read from the table Fi (α) shown in FIG. 15, then the clutch pressure CP is set to the base clutch pressure BP × (1 + KI) in S47, and then the process proceeds to S51. That is, if the hydraulic pressure of the clutch K0 decreases too fast, the gear ratio advancement Gs increases, and thus the pressure is corrected to the pressure increasing side as described above. On the other hand, if the determination result in S44 is No, the process proceeds to S48, the deviation β is calculated by the illustrated equation, and then the depressurization coefficient KD is read from the table Fd (β) illustrated in FIG. 16 in S49. Then S50
Clutch pressure CP is base clutch pressure BP × (1
-KD) is set and then the process proceeds to S51. That is, if the decrease in the oil pressure of the clutch K0 is too slow, the gear ratio advancement Gs becomes small, and therefore the correction is made to the pressure reducing side as described above.

Next, the control signal corresponding to the clutch pressure CP set in any of S42, S47 and S50 is output to the drive circuit for the linear solenoid valve 100, and the drive pulse signal or the drive pulse signal corresponding to the control signal is output. The drive current is output to the linear solenoid valve 100, which results in the clutch K0.
Becomes the clutch pressure CP. After S51, the control returns to S1, and S1 and subsequent steps are repeated. However, this shift control ends when the 2-3 shift flag SF is reset after the control section “3” has elapsed or after a predetermined time has elapsed.

Next, the operation of the shift control described above will be described. As described above, the main variable gear ratio advancement Gm and the auxiliary variable gear ratio progression Gs are obtained in real time, and the hydraulic pressure of the clutch K0 is feedback-controlled so as to follow the preset shift progress target value M. It is possible to suppress the shift shock by executing the 2-3 shift while balancing the shift progress of the auxiliary transmission 3 and the auxiliary transmission 4. In the control sections "1" and "2", the safety factor S of the hydraulic pressure setting is changed to a small value, so that the hydraulic pressure drop of the clutch K0 that is disengaged can be promoted and the responsiveness thereof can be enhanced, whereby the feedback control The followability can be improved. Moreover, since the safety factor S is linearly gradually decreased in the control section "2", it is possible to prevent a shift shock due to the change of the safety factor S.

Further, the feedback control is performed during the period in which the safety coefficient S is changed to be small, in addition to the period in which the both gear ratio advances Gm and Gs are changed, so that the slippage of the clutch K0 caused by the change in the safety coefficient S can be prevented. You can also compensate.
Further, even in the control section "3" in which the shift is substantially completed, the clutch pressure is feedback-controlled, so that the clutch pressure immediately after the shift can be stabilized. It should be noted that in the above-described embodiment, the 2-3 shift as a typical example in which the main transmission 3 and the sub transmission 4 are simultaneously shifted is described as an example.
The present invention can be similarly applied to various other gear shifts such as engaging the brake B0 while releasing the clutch K0 among 0 and the brake B0. Further, the safety coefficient S does not necessarily have to be 1.0 at the end of the control section "1", and may be set to 1.0 in the middle of the control section "2".

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an automatic transmission connected to an engine.

FIG. 2 is an overall configuration diagram of a mechanical configuration of the automatic transmission.

FIG. 3 is a table showing a relationship between a shift speed of the automatic transmission and a fastening pattern.

FIG. 4 is a table showing a gear ratio of the automatic transmission, a main gear ratio, and a gear ratio of the auxiliary gear ratio.

FIG. 5 is a hydraulic circuit diagram for a main transmission of the automatic transmission.

FIG. 6 is a hydraulic circuit diagram for an auxiliary transmission of the automatic transmission.

FIG. 7 is a table showing a relationship among a range and a shift speed of the automatic transmission, a fastening pattern, and a solenoid pattern.

FIG. 8 is a configuration diagram of a control system of the automatic transmission.

FIG. 9 is an overall schematic flowchart of shift control of 2-3 shift.

FIG. 10 is a flowchart of clutch pressure control section determination processing.

FIG. 11 is a flowchart of base clutch pressure setting processing.

FIG. 12 is a flowchart of clutch pressure feedback control.

FIG. 13 is a time chart of control sections, shift flags, safety factors, and the like.

FIG. 14 is a diagram of a shift progress target value.

FIG. 15 is a characteristic diagram of a pressure increase gain.

FIG. 16 is a characteristic diagram of decompression gain.

[Explanation of symbols]

 AT Automatic transmission 3 Main transmission 4 Sub transmission K0 Clutch B0 Brake 100 Linear solenoid valve 120 Control unit

Claims (5)

[Claims] 1. An automatic transmission including a main transmission and an auxiliary transmission connected to the main transmission, wherein an actual shift progress state is set in advance during a simultaneous shift in which the main transmission and the auxiliary transmission are simultaneously switched. Feedback means for performing feedback control so as to follow the target value of the gear shifting progress state, and, at the time of the simultaneous gear shifting, after the gear shifting command, the safety coefficient in the hydraulic pressure setting of the friction engagement element to be controlled by the feedback control is changed to a small hydraulic pressure. An automatic transmission control device comprising: a hydraulic pressure changing unit that reduces the hydraulic pressure. 2. The control device for an automatic transmission according to claim 1, wherein the shift progressing state is a gear ratio advance of the main transmission and a gear ratio advance of the auxiliary transmission. 3. The feedback means is configured to perform feedback control during a period in which the safety factor is being changed to a small value, in addition to a period in which the both gear ratio advancement changes. Item 3. A control device for an automatic transmission according to item 2. 4. The hydraulic pressure changing means has a gear ratio advance of 1
The control device for the automatic transmission according to claim 2, wherein the safety coefficient is restored to an original value when the safety coefficient reaches 00%. 5. The control device for an automatic transmission according to claim 4, wherein the feedback means is configured to perform feedback control also for a predetermined period after the safety coefficient is restored.