JPH05322017A - Shift control unit for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent shift chock by providing a correcation means which corrects a running speed of a gear ratio shifting rate of an auxiliary transmission according to charge rate of rotation. CONSTITUTION:An auxiliary transmission 4 is feedback controlled by a feedback control means so that a gear ratio shifting rate Gs of the auxiliary transmission follows a specified target gear ratio shifting rate Gst which is set according to a gear ratio shifting rate Gm of a main transmission 3 at shifting to specified speed. Change rate DELTATrp of input rotation speed of a transmission AT is detected by a rotation change rate detection means. Running speed of the gear ratio shifting rate of the auxiliary transmission 4 is corrected by a correction means according to the detected rotation change rate DELTATrp. As a result, when the main transmission 3 and the auxiliary transmission 4 are shifted simultaneously, torque fluctuation under feedback control of the auxiliary transmission 4 can be prevented.

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, which comprises a main transmission and an auxiliary transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission, for example, an automatic transmission for automobiles, is provided with a multi-step gear mechanism and a hydraulic friction element to switch the operating state of the friction element, that is, between engagement and disengagement, to realize a multi-speed transmission. Gear shifting is performed by switching the power transmission path of the gear mechanism.

By the way, in recent automatic transmissions, the number of stages has been increasing. Therefore, as shown in JP-A-61-99745, the automatic transmission is composed of a main transmission and an auxiliary transmission. Thus, the main transmission and the auxiliary transmission are simultaneously or alternately switched, that is, the transmission is changed.
Both the main transmission and the sub-transmission may be composed of a multi-stage speed change gear mechanism and a hydraulic friction element.

When the automatic transmission is composed of a main transmission and an auxiliary transmission, the main transmission and the auxiliary transmission are used when obtaining a specific shift as a whole of the automatic transmission, for example, when shifting from the second speed to the third speed. It may be necessary to shift both and. In such a simultaneous shift, a shift shock is more likely to be a problem than a shift only by the main transmission or a shift by only the auxiliary transmission. Such a problem becomes particularly noticeable when the shift direction of the main transmission and the shift direction of the auxiliary transmission are opposite to each other (when one shifts up and the other shifts down).

Therefore, in the above publication, when the main transmission and the sub transmission are simultaneously switched to perform a predetermined gear shift, the sub transmission is stopped before the end of the main transmission. That is, it is also disclosed that the shift shock of the sub-transmission is prevented at least from the end of the shift of the main transmission.

[0006]

By the way, in the case of gear shifting by simultaneously switching the main transmission and the sub transmission, the main transmission and the sub transmission have a predetermined relationship from the viewpoint of preventing shift shock. It is conceivable to perform gear shift control while keeping the relationship unrelated. Therefore, the applicant of the present invention implements feedback control of the auxiliary transmission so that the gear ratio advance of the auxiliary transmission follows the target gear ratio advance set according to the gear ratio advance of the main transmission. developed.

As described above, the auxiliary transmission is feedback-controlled so as to follow the target gear ratio advance set according to the gear ratio advance of the main transmission, whereby the gear ratio advance of the auxiliary transmission is increased. Is not only advantageous for preventing gear shift shock, but it is also extremely easy to set the target gear ratio advance to 100% before the gear ratio advance of the main transmission reaches 100% (shift completion). It is possible to prevent the shift of the auxiliary transmission from ending at least later than the shift of the main transmission.

However, it has been found that when the feedback control of the auxiliary transmission is carried out as described above, a considerable torque fluctuation occurs due to the feedback control itself. That is, the progress speed of the gear ratio advance of the auxiliary transmission may be increased or decreased by the feedback control. However, due to the change of the advance speed, the inertia release degree of the rotary system of the auxiliary transmission (When the transmission is shifted up) or the degree of inertia absorption (when the auxiliary transmission is shifted down) tends to fluctuate, which causes torque fluctuations.

It is an object of the present invention to presuppose that the auxiliary transmission is feedback controlled so as to follow the target gear ratio advance set according to the gear ratio advance of the main transmission. An object of the present invention is to provide a shift control device for an automatic transmission, which is capable of effectively preventing torque fluctuation caused by itself.

[0010]

In order to achieve the above object, the present invention has the following configuration. That is, in an automatic transmission including a main transmission and an auxiliary transmission, and performing at least a specific shift by shifting the main transmission and the auxiliary transmission together, at the time of the specific shift, the auxiliary transmission A feedback control means for controlling the feedback of the auxiliary transmission so that the gear ratio advance of the transmission follows a predetermined target gear ratio advance set according to the gear ratio advance of the main transmission; A rotation change rate detecting means for detecting a change rate of the input rotation speed of the transmission, and a traveling speed of the gear ratio advance of the auxiliary transmission are corrected according to the rotation change rate detected by the rotation change rate detecting means. And a correction means.

The correction by the correction means can be performed only when the rotation change rate detected by the rotation change rate detection means falls outside a predetermined range.

The correction by the correction means is performed by stopping the control by the feedback control means and performing the feed forward control of the auxiliary transmission so that the gear ratio advance thereof changes smoothly. You can

When the rotation change rate detected by the rotation change rate detecting means returns to within the predetermined range, the charge
The feedback control by the feedback control means can be restored.

The correction by the correction means can be performed by changing the control gain of the feedback control means.

[0015]

According to the present invention, the feedback control is performed while associating the shift control of the auxiliary transmission with the gear ratio advance indicating the shift progressing state of the main transmission, so that the shift control as a whole is made more appropriate. It is possible to effectively prevent the shift shock.

Further, considering that the torque fluctuation which is about to occur due to the feedback control appears in the rate of change of the input rotational speed of the transmission including other factors, this input is taken into consideration. Since the advancing speed of the gear ratio advance of the auxiliary transmission is corrected according to the rotation change rate, it is possible to effectively prevent the torque fluctuation as a whole.

According to the second aspect of the present invention, the correction by the correction means is prohibited when the feedback control is well performed and the torque fluctuation does not occur or can be ignored even if it occurs. Then, this is preferable in preventing a situation in which torque fluctuations due to the correction itself occur.

According to the third aspect of the present invention, the gear ratio advancement speed of the auxiliary transmission can be changed extremely smoothly to prevent undesirable torque fluctuation due to feedback control. Will be preferred.

With the structure as described in claim 4, it is confirmed that the torque fluctuation is in a state where it does not pose a problem, the feedback control is restored, and the shift shock as a whole shift is obtained. It is preferable for effectively preventing the above.

With the structure described in claim 5, the correction by the correction means can be easily performed. Preferred aspects of the invention and advantages thereof will become apparent from the description of the examples below.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. Multi-speed transmission gear mechanism As shown in FIG. 1, the output of the engine 1 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 is arranged between the pump 20 coupled to the engine output shaft 1 a, the turbine 21 arranged opposite to the pump 20, and the pump 20 and the turbine 21. And a stator 22. This 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 includes a stator 22.
Is allowed to rotate in the same direction as the pump 20, and rotation in the opposite direction is prohibited.

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 pre-stage planetary gear mechanism 3A includes three gear elements of a sun gear 30, a pinion gear 31, and a ring gear 32, and a planetary carrier 34. Rear planetary gear mechanism 3B, sun gear 35 and pinion gear 3
6 and ring gear 37, and three planetary carriers 38. The carrier 34 and the sun gear 35 are connected to each other, and the sun gear 30 and the carrier 3 are connected.
8 and the carrier 38 is connected to the output shaft 3 a of the main transmission 3.

The converter output shaft 2a is connected to the ring gear 32 via the first clutch K1 and is also connected to the ring gear 37 via the second clutch K2. The main transmission 3 includes three brakes fixed to the case 5, that is, a first brake B1, a second brake B2, and a third brake B3. The brakes B1, B2, B3 and the clutch K1, which are friction engagement elements,
Forward 3 depending on the combination of the fastened / released state of K2
In addition to these, one-way clutches OWC1 and OWC2 are also provided.

The sub-transmission 4 will be described. The sub-transmission 5 is composed of a planetary gear mechanism including a sun gear 40, a pinion gear 41, a ring gear 42, and three planetary carriers 43. Ring gear 4
2 is coupled to the input shaft 4a of the auxiliary transmission 4, and the input shaft 4a
The a is coupled to the output shaft 3a of the main transmission 3 via a gear 44, and the carrier 43 is coupled to the output shaft 4b of the auxiliary transmission 4. The sub transmission 4 includes a brake BO fixed to the case 5, and the sun gear 40 and the ring gear 42 are coupled to each other via the brake BO and the clutch KO. It is configured such that a high speed stage (H) and a low speed stage (L) can be achieved by a combination of the engagement and disengagement states of the brake BO, which is a friction engagement element, and the clutch K0. In addition to these, a one-way clutch OWCO is also provided. ing.

The automatic transmission AT has brakes B1 and B.
2, B3, B0 and the clutches K1, K2, KO in the engaged / released combinations, 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.

Hydraulic Circuit 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 PL generated by an oil pump (not shown) is supplied from the line pressure oil passage 57 to the manual valve 50, which is connected to the shift lever. By operating the shift lever, it is possible to switch among the neutral position (N), the parking position (P), the reverse position (R), and the drive position (D). The drain pressure and R range corresponding to these positions can be selected. The pressure, the D range pressure, (however, the range pressure itself is equal to the line pressure PL) are supplied to the corresponding ports.

The hydraulic systems of the brakes Bl, B2, B3 and the clutches K1, K2, which are the friction engagement elements of the main transmission 3, will be described. As shown in FIG. 5, three shift valves 51, 52, 53 are provided. And two pressure control valves 54, 55 are provided, and each shift valve 51, 52,
At 53, four lands are formed on the spool, and the spool is biased to the left by a spring 58.
The oil chamber 56 at the left end is an ON / OFF type solenoid valve SOL
Line pressure PL is supplied via A, SOL B, SOL C,
When these solenoid valves are ON, the oil 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. Further, when these solenoid valves are OFF, the line pressure PL is supplied to the oil chamber 56 and the positions are shown in the lower halves of the respective lines.

The brake B1 is provided with 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 via the shift valve 53 and the oil passage 66. Further, the R range pressure can be supplied to the brake B2 from the R range pressure oil passage 68 via the shift valve 51, the oil passage 69, the shift valve 53, and the oil passage 66.
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 PL can be supplied through 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 boat.

Further, accumulators 63, 67 and 76 for receiving the modulator pressure PM 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 PC regulated by the solenoid valve 86 is supplied through the oil passage 87. This control pressure PC causes the hydraulic pressure at the output port 84 (brake B3 and clutch K
The hydraulic pressure supplied to 1) is controlled. 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 BO and the clutch KO, 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 at the left end is drained. ON in room 93
The line pressure PL can be supplied through the OFF type solenoid valves SOL D and SOL E.

A line pressure oil passage 57 is connected to the brake BO.
From the shift valve 90, oil passage 94, shift valve 9
1. The line pressure PL can be supplied via the oil passage 95.
The line pressure PL can be supplied to the clutch KO 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, by setting the solenoid valve SOL D to 0N, the clutch K
From line pressure oil passage 57 to shift valve 90, oil passage 97, shift valve 91, linear solenoid valve 100.
The hydraulic pressure regulated by the linear solenoid valve 100 can be supplied through the oil passage 101 and the oil passage 99 in which the solenoid valve is interposed, and by turning on both the solenoid valves SOL D and E,
It is possible to drain the hydraulic pressure of the clutch KO via the oil passage 101. Incidentally, reference numerals 102, 103 and 10 in the figure
Reference numeral 4 is an orifice, X is a drain port, and an accumulator 96 for receiving the modulator pressure PM is connected to the oil passage 95.

Ranges and shift speeds related to the automatic transmission AT, positions of shift valves 51, 52, 53, 90, 91, that is, ON / OFF of solenoid valves SOL A to SOL E.
Of the solenoid pattern and the friction fastening requirements (K1, K2,
The relationship with the fastening pattern (B1, B2, B3, KO, BO) is as shown in FIG. The gear stage related to the main transmission 3 and ON / OF of the solenoid valves SOL A to SOL C
F solenoid pattern and friction fastening elements (K1, K
2, B1, B2, B3) is shown in FIG. 8, and the relationship between the second speed (A), the second speed (B), and the third speed (A) is shown in FIG. The reason why the clutch K1 is engaged when the shift stage is a complementary rib and when the neutral range (N) and the parking range (P) are set is to enhance the responsiveness of switching to the traveling range or the reverse range.

Control System Next, a control system for controlling the automatic transmission AT will be described. As shown in FIG. 9, 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. A detection signal of the second sensor 11l that detects the rotation speed of the shaft 3a and a third sensor 1 that detects the rotation speed of the output shaft 4b of the auxiliary transmission 4.
12 detection signals, shift signals corresponding to respective ranges detected by a plurality of switches provided on the shift lever 113, and a throttle opening sensor 114 for detecting the opening of the throttle valve of the engine 1. The signal TVO, the vehicle speed signal SD from the vehicle speed sensor 115, and other detection signals from the brake switch or the like are input. The first to third sensors 110 to 112 are, for example, electromagnetic pickup type sensors and are shown in FIG.

The control unit 120 outputs drive signals to the solenoid valves SOL A to SOL E, and the linear solenoid valves 86, 100, 1
A drive pulse signal is output to 16. However, the linear solenoid valve 116 is for adjusting the modulator pressure. This control unit 120
Is an A / D converter for A / D converting an input signal as necessary, a plurality of waveform shaping circuits, an input / output interface,
A microcomputer, a plurality of drive circuits, and the like are provided, and the ROM of the microcomputer includes a general shift map having vehicle speed and throttle opening as parameters, and shift control based on various input signals and shift maps. A control program (however, including the solenoid pattern corresponding to the range and the shift stage) 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.

Outline of Shift Control Next, the points of the shift control will be described. In the embodiment,
Shifting between the 2nd speed and the 3rd speed simultaneously switches (shifts) both the main transmission 3 and the sub transmission 4, but from the 2nd speed when shifting up, the shock of shifting becomes more problematic. The shift to the third speed is defined as a specific shift, and the other shifts are performed in a known manner. The outline of shift control for shifting from the second speed to the third speed, which is the specific shift, will be described with reference to FIG.

At the time of shifting from the 2nd speed to the 3rd speed, the shifting of the main transmission 3 is first started. At the time of shifting from the 2nd speed to the 3rd speed, the third brake B3 for the main transmission 3 is made. Is engaged and the clutch KO of the auxiliary transmission 4 is released. In FIG. 10, after the gear shift command is issued, the engagement hydraulic pressure of the third brake B3 rises with a delay of the invalid stroke of (the piston of) the third brake B3 for the main transmission 3. The engagement hydraulic pressure for the third brake B3 is set to, for example, a value corresponding to the throttle opening (see FIG. 15), and feed forward control is performed from the start to the end of the shift.

When the actual gear ratio advance Gm of the main transmission 3 reaches a predetermined value Gmo (for example, 5%), the sub transmission 4 starts shifting. The gear shift of the sub transmission 4 is performed at the initial predetermined time TS
For o, the engagement hydraulic pressure Pko of the clutch KO is
This is performed by controlling the forward (see FIG. 16). By this initial feedforward control, the engaging hydraulic pressure of the clutch KO is reduced from P3 to P4,
This P4 becomes the initial value of the feedback control (final value of the feedforward control) described later.

When the feedforward control of the auxiliary transmission 4 is completed, the engagement hydraulic pressure Pko of the clutch KO is reached.
However, feedback control is performed until the shift of the auxiliary transmission 4 is completed. This feedback control is performed so that the actual gear ratio advance Gs of the auxiliary transmission 4 becomes the target gear ratio advance Gst as a predetermined target value. This target value Gst
17, the gear ratio advance of the main transmission 3 is 1 as shown in FIG.
It is set so that the gear ratio advancement Gs of the auxiliary transmission 4 becomes 100% (when the auxiliary transmission 4 finishes shifting) when it reaches Gm1 (for example, 90%) before it reaches 00%. ..

The gear ratio advance will be described below. First, taking the main transmission 3 as an example, the rotation speed of the converter output shaft 2a, which is the input rotation speed of the main transmission 3, is Nmi, and the output shaft 3 is the output rotation speed of the main transmission 3.
When the rotation speed of b is Nmo, the actual gear ratio Gr of the main transmission 3 is as follows. Gr = Nmi / Nmo In addition, the gear ratio (gear ratio progress = 0%) before the start of the shift is Gr.
s, the gear ratio at the end of the shift is Gre (gear ratio progress = 100
%), The current gear ratio advancement Gm is as follows. Gm = (Grs-Gr) / (Grs-Gre) The gear ratio advancement Gs of the auxiliary transmission 4 is also set in the same manner. In FIG. 10, the rotation speed of the input shaft 4a of the auxiliary transmission 4 is Nsi, and the output shaft thereof is Nsi. The rotational speed of 4b is shown as Nso.

Details of Shift Control Next, details of the shift control will be described with reference to the flowcharts shown in FIGS. In the following description, Q indicates a step. First, in Q1 of FIG. 11, signals from each sensor, at least the throttle opening T
VO and vehicle speed are read. In Q2, it is determined whether or not the gear shift is to be performed based on the gear shift characteristics set using the throttle opening and the vehicle speed as parameters.

In Q3, it is determined whether or not the determination result in Q2 is a shift from the 2nd speed to the 3rd speed. When the determination in Q2 is NO, there is no shift or the 2nd speed to the 3rd speed. The shift is executed in a known normal mode, which is not the shift of No., and at this time, since it has nothing to do with the shift control of the present invention, the process returns to Q1.

When the determination in Q3 is YES, the timer TO is started in Q4. After that, in Q5, the map shown in FIG. 15 is collated, the basic control value PB3 for the main transmission 3 is read based on the timer value TO, and in Q6, the basic control value PB3 is output. The basic control value PB3 is a voltage signal corresponding to the engagement hydraulic pressure of the third brake B3.

At Q7, the actual gear ratio advancement Gm of the main transmission 3 is read (calculated). After this, Q8
, The actual gear ratio advancement Gm is a predetermined value Gmo at which the shift of the auxiliary transmission 4 is started (see FIGS. 10 and 17).
Is determined to be greater than or equal to. When the determination in Q8 is NO, the time to start shifting the auxiliary transmission 4 has not arrived, so the process returns to Q5 and only the shifting of the main transmission 3 proceeds.

If the determination in Q8 is YES, it is determined in P9 whether the actual gear ratio advancement Gm of the main transmission 3 is less than 100%. Initially, the determination in Q9 becomes NO and the process shifts to Q10. In Q10, the main transmission 3
It is determined whether the actual gear ratio advancement Gm is less than 97%.

Initially, the determination in Q10 is YES, and the process proceeds to Q21 in FIG. In Q21, timer TS is 0
If YES in the determination in Q21, the timer TS is started in Q22, the flag is reset to 0 in Q23, and the process proceeds to Q24. When the determination in Q21 is NO, the process proceeds to Q24 without passing through Q22 and Q23.

In Q24, the count value of the timer TS is
It is determined whether or not it is smaller than TSo, that is, whether or not it is within the period for performing feed-forward control of the auxiliary transmission 4 as shown in FIG. Initially, the determination of Q24 is YES
Then, the process shifts to Q25. In Q25, as shown in FIG. 16, the basic control value Pko for (the clutch KO of) the auxiliary transmission 4 is set based on the count value of the timer TS. Then, in Q36, this basic control value P
ko is output.

When the determination in Q24 is NO, the feedback control of the auxiliary transmission 4 is performed. At this time, first, in Q26, the actual gear ratio advance Gs of the auxiliary transmission 4 is read (calculated). Thereafter, in Q27, it is determined whether or not the flag is 1. Q27
At the first transition to, the flag is reset to 0 in Q23, and the determination in Q27 is NO. This Q27
When the determination is NO in Q28, in Q28, the final value of the feedforward control of the auxiliary transmission 4 is corrected and optimized by the learning control, and then the process proceeds to Q29. Sets the flag to 1.
Since the learning control in Q28 is not directly related to the present invention, its detailed description will be omitted.

At Q29, it is judged if the actual gear ratio advance Gs of the auxiliary transmission 4 is less than 100%. Initially, the determination in Q29 is YES, and the process proceeds to Q30. In Q30, the target gear ratio advancement Gst of the auxiliary transmission 4 with respect to the actual gear ratio advancement Gm of the main transmission 3 is determined by collating the map shown in FIG.

Next, at Q31, the actual gear ratio advance Gs of the auxiliary transmission 4 is subtracted from the target gear ratio advance Gst to calculate the gear ratio advance deviation ΔGs. After this,
In Q32, the deviation ΔGs calculated in Q31 is shown in FIG.
Check the feedback correction amount ΔP with the map shown in FIG.
FB is determined. As shown in FIG. 18, the deviation ΔG
The dead zone is set so that the feedback correction amount ΔPFB becomes zero when s is small.

Thereafter, in Q33, as will be described later, the feedback correction amount ΔP is set in accordance with the rate of change of the turbine rotation speed, that is, the rate of change of the input speed of the main transmission 3.
FB is corrected and the final value of feedback correction amount ΔPk
o is determined.

After Q33, in Q34, the main transmission 3
The actual gear ratio advancement Gm is compared with the map shown in FIG. 20, and the basic control value Pko (Gm) for feedback control is obtained.
Is determined. Subsequently, in Q35, the feedback control amount (final value) ΔPko is added to the basic control value Pko (Gm) to calculate the final control value Pko. Then, the control value Pko set in Q35 becomes Q3
It is output at 6.

When the gear shift of the auxiliary transmission 4 progresses and the gear ratio advance Gs increases, the determination of Q29 eventually becomes NO. At this time, when the shift of the auxiliary transmission 4 is completed,
The timer TS is reset to 0 in Q37, and Q38
After the flag is reset to 0 at, the process returns to Q5. Further, if the shift of the sub transmission 4 does not end even if the gear ratio advance of the main transmission 3 reaches 97%, the determination in Q10 is NO, and in this case, the shift of the sub transmission 4 is changed in Q12. After forcibly ending, shift to Q37.

When the gear shift of the main transmission 3 further progresses and the actual gear ratio advance Gm exceeds 100%, the determination in Q9 becomes NO, and after the learning control in Q11 is performed, Q1 Return to. In the learning control in Q11, the target time of the main transmission 3 is learned and corrected, but since it is not directly related to the present invention, its explanation is omitted.

Correction according to the rate of change in turbine rotation speed (Q3
3) Next, the correction according to the rate of change of the turbine rotation speed performed in Q33 will be described with reference to FIG.
The process in Q33 is performed to prevent the torque fluctuation that is likely to occur due to the feedback control of the auxiliary transmission 4.

First, at Q101 in FIG. 13, the turbine rotation speed Trp is read. Next, in Q102, by subtracting the previous Trp which is the previous turbine rotational speed from the turbine rotational speed Trp read this time,
The rotation change rate ΔTrp is calculated.

In Q103, with reference to the map shown in FIG. 19, the correction coefficient λ corresponding to the rotation change rate ΔTrp is determined. Next, in Q104, the feedback correction amount ΔPFB determined in Q32 is multiplied by the correction coefficient λ to determine the final correction value ΔPko used in Q35.

Here, in FIG. 19, what is shown as a reference value is an ideal value as the turbine rotation speed change rate ΔTrp, and the auxiliary transmission 4 is in accordance with the target gear ratio advance Gst.
This reference value can be obtained if the gear ratio advancement Gs of (1) changes. In FIG. 19, the correction coefficient λ is set to be 1 within a predetermined range from this reference value, and is set as a dead zone in which no correction is made to the feedback correction amount ΔPFB in this predetermined range. ing.

Further, the correction coefficient λ is the rotation change rate ΔTrp.
Is set to be gradually smaller as it deviates from the reference value, and the correction coefficient λ is made zero when the rotation change rate ΔTrp is largely deviated from the reference value by a predetermined amount or more.
The fact that the correction coefficient λ becomes smaller than 1 means that the feedback control gain shown in FIG. 18 is made small after all (corresponding to the change shown by the solid line to the broken line in FIG. 18). -Abrupt change of the rotation change rate ΔTrp due to the duck control is prevented.

When the correction coefficient λ is zero, the feedforward control is substantially based on the control basic value Pko (Gm) shown in FIG. Of course, as is clear from the setting of FIG. 19, the above-mentioned feed forward
If the rotation rate of change approaches the reference value from the state of the control mode and the correction coefficient λ becomes a value larger than 0 again, the feedback control is restarted.

As described above, when the rate of change in rotation ΔPrp is out of the predetermined range, the feedback correction amount is reduced and the gear ratio advance Gs of the auxiliary transmission 4 caused by the feedback control is suddenly increased. Such a change, that is, a rapid change in the rotation change rate ΔTrp is suppressed, and torque fluctuation is prevented. That is, in FIG. 14, the solid line indicates the ideal rate of change of the turbine rotation speed, but the fact that the feedback control greatly deviates from the ideal state on the solid line as indicated by the broken line is due to the torque shock. Will be a major cause of Then, in the present invention, the control as shown in FIG. 13 is performed to prevent the rapid change of the rotation change rate, and thus the torque shock and eventually the torque fluctuation in which such a torque shock repeatedly occurs can be prevented. become.

In the above embodiments, the case where the auxiliary transmission 4 is downshifted has been described. However, even when the auxiliary transmission 4 is upshifted (3 → 2 shift in the embodiment), the gear ratio of the auxiliary transmission 4 is changed. The progress Gs can be feedback-controlled as well as being controlled as shown in FIG.
Of course, the auxiliary transmission 4 is replaced with the main transmission 3 and the torque converter 2.
The same can be applied to the case where it is arranged between and.

The reference value shown in FIG. 19 can be changed according to the gear ratio advancement Gm of the main transmission 3, for example. That is, the rate of change of the turbine rotation speed from the start to the end of the shift is not always constant, but the rate of change of the rotation is small at the beginning of the start of the shift, the rate of change of the rotation is large during the middle of the shift, and the end of the shift is changed. In order to reduce the rate of change of rotation again, the main transmission 3 that indicates at what time during the shift
The reference value can be changed based on the gear ratio advance degree of (the characteristic line shown in FIG. 19 is offset left and right as a whole together with the reference value).

[Brief description of drawings]

FIG. 1 is an overall view showing a drive system of an automobile.

FIG. 2 is a detailed view showing the configuration of the automatic transmission shown in FIG.

FIG. 3 is a diagram showing a relationship between a shift speed of an automatic transmission and operating states of respective friction elements.

FIG. 4 is a diagram showing a relationship between a gear stage of an automatic transmission, a gear stage of a main transmission, a gear stage of an auxiliary transmission, and a gear ratio.

FIG. 5 is a diagram showing an example of a hydraulic circuit for a main transmission.

FIG. 6 is a diagram showing an example of a hydraulic circuit for an auxiliary transmission.

FIG. 7 is a diagram showing a relationship between a shift stage of an automatic transmission, operating states of respective friction elements, and operating states of solenoids incorporated in a hydraulic circuit.

FIG. 8 is a diagram showing a relationship between a gear stage of a main transmission, an operating state of a friction element, and an operating state of a solenoid incorporated in a hydraulic circuit.

FIG. 9 is a diagram showing a control system of an automatic transmission.

FIG. 10 is a diagram schematically showing a shift control when the main transmission and the auxiliary transmission are simultaneously switched.

FIG. 11 is a flow chart showing a control example of the present invention.
To.

FIG. 12 is a flow chart showing a control example of the present invention.
To.

FIG. 13 is a flowchart showing a control example of the present invention.
To.

FIG. 14 is a diagram schematically showing the relationship between the fluctuation of the rate of change of the turbine rotation speed and the torque shock.

FIG. 15 is a map used in a control example of the present invention.

FIG. 16 is a map used in a control example of the present invention.

FIG. 17 is a map used in a control example of the present invention.

FIG. 18 is a map used in a control example of the present invention.

FIG. 19 is a map used in a control example of the present invention.

FIG. 20 is a map used in a control example of the present invention.

[Explanation of symbols]

 1: Engine 2: Torque converter 2a: Turbin output shaft (input shaft of main transmission) 3: Main transmission 4: Sub transmission 120: Control unit Gm: Gear ratio advance of main transmission Gs: Sub Gear ratio advance of transmission Gst: Target gear ratio advance of auxiliary transmission ΔPFB: Basic value of feedback correction amount ΔPko: Final value of feedback correction amount ΔTrp: Rate of rotation change λ: Correction coefficient

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Sumimoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (5)

[Claims] 1. An automatic transmission comprising a main transmission and an auxiliary transmission, wherein at least a specific shift is performed by shifting the main transmission and the auxiliary transmission together. A feedback control means for controlling the feedback of the auxiliary transmission so that the gear ratio advance of the auxiliary transmission follows a predetermined target gear ratio advance set in accordance with the gear ratio advance of the main transmission. A rotation change rate detecting means for detecting a change rate of the input rotation speed of the transmission; and a speed of progress of a gear ratio advance of the auxiliary transmission according to the rotation change rate detected by the rotation change rate detecting means. A shift control device for an automatic transmission, comprising: 2. The correction unit according to claim 1, wherein the correction unit executes the correction only when the rotation change rate detected by the rotation change rate detection unit is out of a predetermined range. 3. The feed forward control according to claim 2, wherein the correction by the correction means stops the control by the feedback control means and causes the auxiliary transmission to change its gear ratio advance smoothly. It is done by controlling the machine. 4. The feedback control by the feedback control means is restored when the rotation change rate detected by the rotation change rate detecting means returns to within the predetermined range. .. 5. The method according to claim 1 or 2, wherein the correction by the correction means is performed by changing a control gain of the feedback control means.