JPS624950A - Speed change controller for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce the speed change shock by starting the speed change of the first transmission in precedence to the speed change of the second transmission and terminating the speed change of the both transmissions at a same time. CONSTITUTION:The speed change starting instruction (square mark) of the first transmission is outputted in precedence to the speed-change starting instruction ( ) of the second transmission, and control is performed so that the speed change completion time of the both transmissions is made equal. Therefore, even if the first and the second transmissions are shifted in the reverse directions each other, the shift-up and -down feeling can be maintained favorably, and the strange drive feeling such as the down-shift after up-shift or the up-shift after down-shift is not generated.

Description

[Detailed description of the invention]

] Industrial Application Field 1 The present invention relates to a speed change control device for an automatic transmission.
A first transmission capable of automatically changing gears in relation to vehicle speed or slot opening, etc., and a second transmission arranged in series with the first transmission. This invention relates to the defectiveness of a shift control II device for an automatic transmission that achieves multi-speed shifting by shifting the first transmission and the second transmission simultaneously or alternately. [Prior Art] With the rapid spread of automatic transmissions for vehicles in recent years, there has been a shift to a first transmission that can automatically change gears depending on vehicle speed, throttle opening, etc., mainly with the intention of improving fuel efficiency. *Increasingly, a so-called overdrive device with a ratio of 1 or less is installed in series as a second transmission. Also, in view of its function as a second transmission that can switch between a low gear and a high gear, such as an overdrive device, this is actively synchronized with the shift of the first transmission, and a relatively large gear ratio is achieved. By simultaneously or alternately shifting the first speed change example and the second speed change gear having a relatively small speed change gear ratio, the speed change control as shown in part A of FIG.
It is already known that a multi-stage transmission with six forward stages is achieved by
7140). In this way, by arranging the second transmission, which switches between the low speed side and the high speed side, in direct relation to the first transmission, the existing automatic transmission can be used as the basis and design changes can be minimized. Although it is manufactured at the top (1), multi-speed shifting can be easily realized, and many advantages can be obtained such as improved fuel efficiency, improved power performance, and a reduction in the burden on the friction material due to the multi-speed shifting. [16 points to be solved by the invention] However, there is no problem with an automatic transmission that achieves multi-speed shifting by shifting the first transmission and the second transmission at the same time or alternately. If there is, for example, an upshift from the second gear to the 3j* gear in Fig. 2, an upshift from the fourth gear to the fifth gear, or a downshift in the reverse of these, the first and the second transmission in the opposite direction to achieve a new gear.
In this case, simply controlling each shift individually will not only inevitably increase the shift shock, but also cause the shift to start from a downshift even though it is an upshift, or the shift may start from a downshift even though it is an upshift. 〇- There is a problem that the shift characteristics may have a strange driving sensation, such as a subsequent upshift or a downshift after an upshift. In view of these problems, the applicant first filed a patent application filed in 1983-2.
In 19454-5, it was disclosed that good shift characteristics can be obtained by configuring the shift of the second transmission to start and complete during the shift period of the first transmission (hereinafter referred to as an inertia phase). That is, the shift of the second transmission must not start before the start of the shift of the first transmission, and the completion of the shift of the second transmission must not occur after the completion of the shift of the first transmission. This is a disclosure that discloses what must not be done. However, if the second transmission completes the shift later than the first transmission, a sudden rise in the output shaft torque occurs in the remaining inertia phase of the first transmission, increasing the shift shock. A problem was discovered. Furthermore, if the shift timing of both is simply controlled by a timer or the oil pressure level of the frictional engagement device, it is extremely difficult to control such delicate start and end timings at the intended timing. The problem has come up. In other words, the shift start time, shift time, etc. of each part vary slightly due to variations in parts of automatic transmissions, variations in usage conditions, etc., so the difference in shift control timing due to this variation cannot be ignored. (Objective of the Invention 1) The present invention has been made in view of such problems, and for example, by shifting the first transmission and the second transmission in opposite directions to each other, a new Shifting of an automatic transmission that causes little shift shock even when changing gears, and that can always provide a good shift feeling in each vehicle, regardless of variations between individual vehicles. The object of the present invention is to provide a control 'I device.

[Means for Solving Problem 4] The first invention is provided with a first transmission and a second transmission capable of automatically changing gears, and the first transmission and the second transmission are connected to a 101 In a shift control device for an automatic transmission that achieves multi-speed shifting by shifting directly or alternately, means for starting shifting of the second transmission after starting shifting of the first transmission; The above-mentioned object is achieved by including means for terminating the shift of the second transmission in synchronization with the end of the shift of the first transmission. Further, the second invention is provided with a first transmission and a second transmission that can automatically change gears, and the first transmission and the second transmission are shifted simultaneously or alternately to achieve multi-stage transmission. In the shift control device for an automatic transmission, the shift control device for an automatic transmission includes means for starting the shift of the second transmission after starting the shift of the first transmission, and synchronizing with the end of the shift of the first transmission. means for causing the shift of the second transmission to end, and a means for ending the shift of the second transmission based on the result of the previous shift timing
and a means for correcting the speed change control of the transmission, so that the speed change control of the first invention can be reliably executed in each vehicle regardless of various variations in individual vehicles. There are 10- things that I did. In the second invention, before preferred implementation! The key is to judge the result of the shift timing by detecting the rotational speed of the member in the automatic shift example or by detecting the engine rotation j* degrees. This allows the results of the shift timing to be
Able to make appropriate judgments. Preferably, the means for correcting the speed change control is a second
The operating force of the frictional engagement device of the transmission is changed by hydraulic duty control. Thereby, the shift time of the second transmission can be adjusted while avoiding sudden changes in power transmission in the second transmission. Preferably, the means for correcting the speed change control is a second
This method changes the timing of the transmission shift start command for the first transmission. This makes it possible to accurately control the shift start of the second transmission, and indirectly Preferably, the means for correcting the speed change control includes a second
This is to change the timing at which the acting force of the friction washer of the transmission is rapidly relieved. As a result, the end timing of the second transmission can be synchronized with the end of the shift of the first transmission, and it is possible to avoid the remaining inertia phase of the second transmission remaining for a long time after the completion of the shift of the first transmission. I can do it. Preferably, the degree of correction of the speed change control is changed depending on at least one of the engine load, the skewer j*, and the type of speed change. As a result, the speed change control can be corrected appropriately, and the correction can be performed with great effect and without causing hunting or the like. Also, preferably, the change for correcting the speed control comprises:
This is done within a predetermined guard range. As a result, for some reason the correction becomes unreasonably large (
1 can be prevented from being damaged. Furthermore, the present third invention provides a first aspect of the present invention that is capable of automatically changing the gear stage.
Shift control device for an automatic transmission, comprising a transmission and a second transmission, and achieving multi-speed shifting by simultaneously or alternately shifting the first transmission and the second transmission. means for detecting engine load; and means for detecting the engine load;
means for starting the second shift (number of changes) at the same time as the start of the shift of the transmission; and means for terminating the shift of the second transmission in synchronization with the end of the shift of the first transmission. , means for correcting the next shift control of the second transmission based on the result of the previous shift timing when there was no change in engine load during the previous shift,
This prevents the next shift from being improperly corrected based on the results of the shift performed under special conditions. [Operation 1] In the first invention, the second transmission starts shifting after the first transmission starts shifting, and
Weird 3! Since the shift of the second transmission is completed in synchronization with the end of Iso's shift, it is possible to always start an upshift from a high gear shift and a downshift from a low gear shift. upshift or upshift]・later downshift i
There is no strange driving sensation like... or,
It is possible to prevent the output shaft torque from rapidly increasing in the remaining inertia phase of the first transmission, and as a result, it is possible to obtain good transmission characteristics. Further, in the second invention, when performing the upper delivery control, a so-called learning sub-part is performed in which the next shift control of the second transmission is corrected based on the result of the previous shift timing. Therefore, regardless of various variations, each machine is always
Optimal transmission characteristics can be obtained for many automobiles. Furthermore, in this third light, the correction is made only when a so-called normal gear shift is performed without any fluctuation in the engine load, so the shift result performed under special conditions is used as the standard. It is possible to prevent the next gear shift from being improperly corrected. [Embodiment 1] An embodiment of the present invention will be described in detail below based on the drawings. If a new gear is achieved by simultaneously shifting the first transmission 60 and the second transmission 40, in particular the new gear can be achieved by shifting both transmissions 40, 60 in opposite directions. As is clear from FIG. 2, cases in which this is achieved include a shift between the second IF gear and the third gear, or a shift between the fourth gear and the fifth gear. , since the purpose is the same, here the first transmission shifts to a high gear, the second transmission shifts to a low gear, and the automatic transmission as a whole shifts from the second gear to the third gear. An explanation will be given by taking a shift as an example. First, Fig. 1 shows an overall outline of a vehicle automatic transmission to which this embodiment is applied. This automatic transmission includes a torque converter 20 and a transmission part. 2 transmission 40, 3 forward speeds,
A first transmission 60 with one reverse gear is provided. The torque converter 20 includes a pump 21 and a turbine 2.
2. The stator 23 and lock-up clutch 24 are repaired. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carriage 41 of a planetary gear set in the second transmission 40. In the second transmission 40, a planetary pinion 42 rotatably supported by the carrier 41 meshes with a sun gear 43 and a ring gear 44. Further, a clutch Go and a one-way clutch FO are provided between the sun gear 43 and the carrier 41.
A brake Bo is provided between the housing 1-1u and the housing 1-1u. The first transmission 60 is a planetary gear device, and is provided with two rows, one on the front side and the other on the rear side. This planetary gear device includes a common sun gear 61, ring gear 62.63, planetary pinion 64.65,
and carrier 66.67. The ring gear 44 of the second speed change lI40 is connected to the ring gear 62 via the clutch C1. Further, a clutch C2 is provided between the ring gear 44 and the sun gear 61.
is provided. Further, the gear A7 rear 66 is connected to the ring gear 63, and these carriers 66
and ring gear 63 are connected to fi output shaft 70. On the other hand, a brake 83 and a one-way clutch F2 are provided between the carrier 67 and the housing 1-1u, and a one-way/seven-way latch F1 is provided between the sun gear 61 and the housing H11. A brake B2 is provided between the sun gear 61 and the housing l-1t1. This automatic transmission is equipped with a transmission section such as a throttle sensor 100 that detects a throttle opening that reflects the loading condition of the engine 1, and a vehicle speed sensor 102 that detects vehicle speed. The central processing unit (ECLI>104) that receives the input drives and controls the electromagnetic solenoid valves 81 to 84 and SL in the hydraulic control circuit 106 according to a preset shift pattern, as shown in part B of FIG. The gear change control is performed by combining the couplings of each clutch, brake, etc. - ] b - Also, in Fig. 2, the ○ mark indicates the washing machine state, and the X mark indicates the state in which the engine brake is used. The electromagnetic solenoid valves S1 and S2 control the first and second shift valves of the first shift ll60, and The solenoid valve S3 controls a third shift valve that switches between a high speed side and a low speed side of the second transmission 40.The electromagnetic solenoid valve S4 controls a release control valve (rear j), and the electromagnetic The solenoid valves SL are designed to respectively control the lock-up clutch 24 of the torque converter 20. In FIG. 112 is a pattern select switch for selecting E (economic driving), P (power driving), etc., and 114 is a pattern select switch that detects the engine cooling water temperature.
116 is a foot brake; 118 is a water temperature sensor;
1 shows a flake switch that detects the operation of the handbrake. Here, in this embodiment (ball, ship production central processing unit 1
In addition to these input signals at 04, a signal from the Go drum speed sensor 120 is also input in order to recognize the start of a change in the rotational speed of the Co drum member of the second speed change 1140 in response to the speed change command. FIG. 3 shows the main parts of the hydraulic control circuit 106. In the figure, reference numeral 200 is a first shift valve for switching between the first speed state and the second speed state of the first transmission 60, and 81 is an electromagnetic valve for controlling switching of the first shift valve. Solenoid Harz 300 is a third shift valve S3 for switching between the high speed side and the low speed side of the second transmission 40.
controls the switching of the third shift valve 300! Electromagnetic solenoid valve for II, 400,500.600
are respectively the brakes B2. BO, and clutch C
. An accumulator 700 is connected to a shift lever operated by the driver, and a manual valve is shown. The configuration and operation of each of these devices themselves are basically the same as in the prior art, so detailed explanations of the individual devices will be omitted. Further, reference numeral 800 is a release control valve for controlling 111 the time and operating pressure when the action of the brake BO is released by controlling the drain oil pressure of the third shift valve 300. This release control valve 800 includes two lands 802.804 with different face areas A+ and A2 (AI < A2), and the two lands 802.8
Brake B is connected to the port 806 provided at the intermediate position of 04.
The drain oil pressure of O is input. This release control valve 800 can be duty-controlled by an electromagnetic solenoid valve $4 controlled by ECtJ104. Next, the operation of this embodiment will be explained with reference to the flow chart of FIG. First flag T 1. Set it to zero. step 900
When a shift decision is made based on the shift point determined by the vehicle speed and throttle opening at step 902, the first shift) *shift command for the gear 60 (first shift 1 - electric fi! solenoid valve for switching the valve 200) is executed. S1
ON command) is issued, and 82 hydraulic pressure is supplied. Next, in step 904, the shift command for the first transmission 60 is changed to To (To is, for example, as shown in FIG. After a delay of a certain amount of time determined by the throttle opening and the type of shift, in step 906, a shift start command for the second transmission 40 (an electromagnetic solenoid for switching the third shift valve 300) is issued. Valve S3 ON command) is issued, and B
O oil pressure draining is started. Next, in step 908, the rotational speed N co of the Co drum member is monitored. When the start of rotation of the Cot-ram member is detected, in step 910 Bo
A duty control start command is issued, and the So oil pressure is duty-controlled by the electromagnetic solenoid valve S4 so that the value of the rate of change N6° of the rotational speed N co of the Co drum member becomes the set value. By this duty control, while maintaining the transmission torque level of the second shift e140 relatively high, the second shift e140
140, the end point of the shift can be adjusted. That is, as shown in FIG. 3, when the hydraulic pressure of the brake BO is drained, the return speed of the accumulator 500 is suppressed by the action of the check pressing orifice 502, so that the release control valve 800
In this case, when the electromagnetic solenoid valve S4 is turned OFF, the drain oil pressure of the brake Bo is in the state shown on the left side of the figure, and the boats 806 and 808 are short-circuited, causing the brake B
When the O oil pressure is rapidly drained and the electromagnetic solenoid valve S4 is turned on, the state shown on the right side of the figure is reached, and the BO 1-808 is closed, and the BO drain is drained from the orifice 8.
14 for slow draining. As a result, the working oil pressure of the brake BO is
The oil pressure determined by the ratio is maintained, and the gear shift can be completed at a desired time while maintaining the desired torque transmission force. Furthermore, this duty
The initial value of the ratio is determined in relation to the throttle opening, vehicle speed, type of shift, etc. Duty: 15 hours after the start of control
The control is terminated (step 912), and then the Bo oil pressure is quickly drained by turning off the electromagnetic solenoid valve S4 (step 914). The reason for doing this is to quickly complete the shift of the second transmission 1160 when the completion of the shift of the second transmission 40 is later than the completion of the shift of the first shift 1160, and Even when the first transmission 60 and the second transmission 1fi 40 are completed in synchronization, B after the synchronization. This is because if some amount of oil pressure remains, the output shaft torque will drop due to the drag of the brake Bo. At the time when Bo duty control is ended and quick drain is started in step 914, Nc. Step 916), Step 22
= 918, it is determined whether the throttle opening degree θ during the gear change is constant I;, and if it is determined that it is constant, a learning control flow is executed to make the next control more appropriate. Limiting the shifting that forms the basis of learning control to shifting where the throttle opening θ is constant in this way prevents the next shifting from being incorrectly corrected based on the shifting results performed under special conditions. This is to prevent it from happening. Learning control is performed as follows. First step 92
The synchronous rotational speed of the Co drum member Neo-(-NoX(1+ρ); ρ is the gear ratio of the first transmission). Ncoi>N co- holds true (
If so, the completion of the shift of the second transmission 40 is earlier than the completion of the shift of the first transmission 60, so the duty cycle is changed in step 922.
The value of the control time T5 is the time from the start of rotation of the Co drum member to the completion of the shift of the first transmission. Note that the judgment as to whether or not the first transmission has completed shifting is determined by Go.
It is determined whether the drum member rotational speed NCO has reached the synchronous rotational speed measured from the output shaft rotational speed No. If the second transmission 1!140 completes the transmission earlier than the first transmission 60, the Co drum member rotation j*degrees N C
Since o exceeds the synchronous rotational speed once, the time when the synchronous rotational speed is reached again is the time when the shift of the first transmission 60 is completed. In step 924, N c during the duty-control l] time T5 set in step 922. Nc so that the value of can vary from zero to synchronous rotation speed.
Change the prefix of o. As a result, the duty ratio is changed and set. In step 920, N co i > N co−
If not established, the completion of the shift of the second transmission 40 is the first
Since it is considered that the shift is delayed or synchronized with the completion of the shift of the transmission 60, in this case, Tb=7516 is set in step 926. Here, (5 is a constant predetermined depending on the throttle opening and the type of shift. Thereafter, in step 928, N.0 is changed to T
5 to synchronize the completion of shifting.
Ru. Note that steps 800 to 803 regarding the flag T are for substantially stopping the flow until the respective conditions are satisfied in steps 904 and 912. According to this embodiment, the first transmission 60 and the second transmission 1tm
The timing adjustment of the shift with 40 is performed by the duty-ratio control set in relation to the throttle opening, vehicle speed, or type of shift, and the learning correction is performed based on the time of the duty-ratio control side 1. Since this is done by changing the speed, the control can be performed extremely accurately, and as shown in FIG. 8, the shift shock can be suppressed to a small level. That is, in general, when the acting force on the second transmission side is rapidly released, a neutral portion momentarily occurs in the middle of the series of torque transmission systems. If it is on the input side of the first transmission, the engine rotation speed is slot -1! "+-" The output shaft of the first transmission (output of the automatic transmission shaft) torque suddenly decreases, and the shift shock increases accordingly.Furthermore, even if the second transmission is on the output side of the first transmission, the second transmission becomes disconnected from the torque transmission system.
The output shaft torque of the transmission (output shaft of the automatic transmission) similarly decreases, and the shift shock also increases (in this example, the acting force when the second transmission is released by duty ratio control) can be maintained at a desired strength for a desired period of time, so that the output shaft torque does not change suddenly. Next, another embodiment of the present invention is shown in FIG. The steps up to step 1906 are the same as in the previous embodiment. In step 1908, the completion of the gear change calculated from the rotational speed Nco of the GO drum member and the output shaft rotational speed NO at that time is synchronous (when the Co drum member Comparison with the rotational speed N.,' (= (1+ρ) N c
Finish comparing o and N co-. Note that T4 is a time set depending on the throttle opening degree and the type of gear change, as shown in FIG. 7, for example. From step 1916, the learning correction flow begins. First, in step 1916, the throttle opening plane θ during gear shifting is
It is determined whether or not is constant, and if it is constant, proceed to 1918 and Ne. and Neo - Which comparison is made, N co > N co
- is established, it is considered that the completion of the shift of the second transmission is earlier than the completion of the shift of the first transmission, so the process advances to step 1920 and in order to synchronize the completion of the shift, To=T
As shown in FIG. 7, o+4 o No is a constant determined by the throttle opening degree and the type of gear change, and delays the start of the shift of the second safe gear. Also, in 1922, the value of T4 is corrected. N co , N co- in Stella 7' 1918
If this is not true, the completion of the shift of the second transmission was delayed from the completion of the shift of the first transmission, or the completion of the shift of the first transmission was synchronized.
In step one 24, the second
Accelerates the start of gear shifting of the transmission. Note that step 1800-
18 (131a, This is a step regarding the flag T. In this embodiment, (1) The division control in which duty control is not performed is simplified, and the second shift of the first transmission is controlled by learning control. It is possible to control the gear shift timing of the machine well as shown in FIG. (Fig. 3) can be used. However, the lever control by the electromagnetic solenoid valve S4 is not 11, and instead, the release control valve 800 is controlled by the boat t-810.
The configuration is such that throttle pressure is applied from a throttle valve (not shown) to the throttle valves. As a result, the drain oil pressure Pso of the brake Bo is set to a predetermined pressure P80 determined by the throttle pressure applied to Bo 1 810 and the force of the spring 812.
- The above sharpening results in the condition shown on the left side of Figure 2, and the boat 80
6 and 808 to rapidly drain the hydraulic pressure of the brake Bo, and when the hydraulic pressure of the brake Bo falls below the predetermined pressure Pso-, the boat 808 is closed in the state shown on the right side of the figure. As a result, the second transmission can accurately start shifting at any throttle opening, and the second transmission can be drained slowly through the orifice 814. It is possible to maintain the release force at a predetermined value, and it is possible to avoid a decrease in output torque due to the second transmission being in the neutral state as in the above-described embodiment. When the command is issued, the electromagnetic solenoid valve S4 is turned OFF to forcibly short-circuit the boats 806 and 808 to quickly drain the Bo oil pressure. When correcting the timer time To for the start of the gear shift for the machine, it was done by increasing or decreasing it by a certain constant 1111/'. Alternatively, the condition N co > N was satisfied. It is also possible to measure the time and change the value of the correction value To according to this time.In addition, in the above embodiment, the result of the shift timing is
Although this was done by detecting the same rotational speed of the Co drum members, the present invention does not limit the means or method for determining the result of the shift timing.
For example, the eleven detections may be performed by detecting a change in the engine rotational speed or by detecting a change in the oil pressure supplied to the frictional engagement device. Furthermore, in the above embodiment, Ts, Nco, TD, T
4th grade correction P[! engine load (throttle opening)
and the straddle was set depending on the type of gear shifting,
In the present invention, the dependent factors are not limited, and instead of or in addition to these factors, for example, vehicle speed fluctuation may be taken into consideration. [Invention Nordic Song Dynasty 1 As explained above, according to the present invention, the first gear and the second gear are shifted in opposite directions to each other, resulting in a sharp gear position. Even if this is achieved, the feeling of upshifting and town shifting can be maintained well, and strange driving sensations such as town shifting after upshifting or upshifting after downshifting will not occur. Furthermore, as a result of optimal control for each individual vehicle, it is possible to suppress shift shock to an extremely low level.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic block diagram of a vehicle automatic transmission to which the present invention is applied, and Fig. 2 shows the operating state of each friction engagement device installed in the upper automatic transmission. Figure 3 is a circuit diagram showing a part of the hydraulic control circuit, Figure 4 is a block diagram showing the relationship between the electromagnetic solenoid 1 to the valves and the shift valve in the hydraulic control circuit. Figure 6 is a flowchart showing the control flow in the above embodiment device; Figure 6 is a flowchart showing another control flow; FIG. 8 shows an example of a map for the opening degree, and FIG. 8 is a shift characteristic diagram showing a comparison between when the shift timing is synchronized and when the shift timing is not synchronized. BO, B2...brake, Co...clutch, 81~S4...Mfil solenoid valve, 40...
-Second transmission, 60...First transmission, 120...Co drum rotation speed sensor, 200...
First shift valve, 300...Third shift valve, 400.500.600...Accumulator, 502
...Check pressing orifice, 800... Release control valve, 814... Orifice.

Claims (10)

[Claims] (1) A first transmission and a second transmission that can automatically change gears.
A shift control device for an automatic transmission, which is equipped with a transmission and achieves multi-stage shifting by shifting the first transmission and the second transmission simultaneously or alternately, An automatic device characterized by comprising: means for starting the shift of the second transmission after the shift has been started; and means for ending the shift of the second transmission in synchronization with the end of the shift of the first transmission. Shift control device for transmission. (2) A first transmission and a second transmission that can automatically change gears.
A shift control device for an automatic transmission, which is equipped with a transmission and achieves multi-stage shifting by shifting the first transmission and the second transmission simultaneously or alternately, means for starting the shift of the second transmission after the shift has been started; means for terminating the shift of the second transmission in synchronization with the end of the shift of the first transmission; and based on the result of the previous shift timing. 1. A shift control device for an automatic transmission, comprising: means for correcting the next shift control of the second transmission. (3) The shift control device for an automatic transmission according to claim 2, wherein the result of the shift timing is determined by detecting the rotational speed of a member of the automatic transmission. (4) The shift control device for an automatic transmission according to claim 2, wherein the result of the shift timing is determined by detecting an engine rotation speed. (5) The automatic transmission according to claim 2, wherein the means for correcting the speed change control changes the acting force of the frictional engagement device of the second transmission by hydraulic duty control. Gear shift control device. (6) The shift control device for an automatic transmission according to claim 2, wherein the means for correcting the shift control changes the timing of the shift start command for the second transmission with respect to the first transmission. (7) The automatic transmission shift according to claim 2, wherein the means for correcting the shift control changes the timing at which the acting force of the frictional engagement device of the second transmission is rapidly released. Control device. (8) The automatic transmission according to any one of claims 2 to 7, wherein the degree of correction of the shift control is changed depending on at least one of engine load, vehicle speed, and type of shift. Shift control device for transmission. (9) The speed change control for an automatic transmission according to any one of claims 5 to 8, wherein the change for correcting the speed control is performed within a predetermined guard range. Device. (10) A first transmission and a second transmission capable of automatically switching gears are provided, and multi-speed transmission is achieved by shifting the first transmission and the second transmission simultaneously or alternately. A shift control device for an automatic transmission, comprising: means for detecting engine load; means for starting shifting of the second transmission after starting shifting of the first transmission; and shifting of the first transmission. means for ending the shift of the second transmission in synchronization with the end of the shift, and when there was no change in engine load during the previous shift;
Based on the result of the previous shift timing, the next shift timing
A shift control device for an automatic transmission, comprising: means for correcting shift control of the transmission;