JPH0514819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shift control device for an automatic transmission that controls a shift operation in an automatic transmission using a synchronous gear type transmission.

[Conventional technology]

In recent years, automatic transmissions have been widely used, and one form of automatic transmission is a synchronous gear type transmission conventionally used in manual transmissions, which is controlled automatically using a hydraulically controlled actuator and an electronic control device. something is disclosed.

The automatic transmission that performs this automatic speed change control uses a synchronous mesh gear type device, so each time the gear is changed, the clutch is disengaged and the engine and transmission are disconnected. , the clutch must be engaged again. for that,
It takes a considerable amount of time to shift gears, and because the clutch is released during gear shifting, no driving force is transmitted, resulting in a temporary idle state. For this reason, the driver may feel a feeling of weakness or stalling of the vehicle, and may feel uncomfortable when driving.

Therefore, one method to eliminate the above-mentioned problems is to detect the magnitude of the synchronized load during gear shifting, and if the load is too large for the capacity of the synchronizer, it is necessary to shift to a neutral state before the synchronized operation (shift operation). The synchronous load is reduced by so-called double-clutch operation, in which the clutch that was disengaged for a gear shift operation is once engaged, and then the clutch is disengaged again and a synchronous operation is performed to reduce the synchronous load before the synchronous operation. A control method for an automatic transmission has been disclosed in which the time required for shifting is reduced by reducing the amount of time required for shifting, and at the same time, under-synchronization is prevented (see Japanese Patent Laid-Open No. 11754/1983).

[Problems to be Solved by the Invention] However, even in the case of an automatic transmission control device having a means for reducing the synchronization load as described above, for example, a manual five-speed transmission is automatically shifted by an actuator. In automatic transmission control devices,
Gear shifting uses a conical clutch to match the rotation with a synchronizer, so each time the gear is shifted, the clutch must be disengaged and once synchronization is complete, the clutch must be reconnected, resulting in disconnection and disconnection of power transmission between the engine and transmission. The operation is always involved, and even if the time required for synchronized operation is shortened, the time required to engage and disengage the clutch is always necessary, and since the clutch is disengaged during gear shifting, the driving force is reduced. There is a problem in that it is not possible to completely avoid the driver feeling a feeling of weakness, a feeling of stalling, etc.

Therefore, the present applicant installed a variable transmission torque means such as an electromagnetic multi-plate clutch at the position of the 5-speed synchronizer in the transmission section, and activated the variable transmission torque means at the time of upshifting to disengage the clutch. Disclosed is a shift control device for an automatic transmission that allows smooth upshifts without any problems, and the patent application 1986-
The application was filed as No. 166672 (see Japanese Unexamined Patent Publication No. 63-26452).

However, since the shift control device of this automatic transmission is applied only to upshifts, the same problem of time lag during shifting as described above remains when downshifting.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to disengage the clutch at the time of upshifting or downshifting in order to smoothly perform shift control at upshifting and downshifting in automatic shift operation. This is a synchronized gear type automatic that is structured so that it can perform gear shifting operations without any effort, thereby shortening the time required for gear shifting and preventing loss of driving force during gear shifting so that the driver does not feel a time lag in gear shifting. An object of the present invention is to provide a speed change control device for a transmission.

[Means for solving problems]

In order to achieve the above object, the present invention is configured as follows. That is, in the present invention, transmission torque variable means are respectively installed in the highest speed gear and the lowest speed gear, and at the time of shifting, the transmission torque variable means installed in the highest speed gear is first operated, and the transmitted torque is adjusted. The transmission is brought into a neutral state by disengaging the current gear while partially bearing the load, and then, at the time of upshifting, increasing the load torque of the transmission torque variable means attached to the highest gear. to shift to the next gear, and at the time of downshifting, release the transmission torque variable means attached to the highest gear, and
The present invention relates to a shift control device for an automatic transmission, characterized in that the variable transmission torque means attached to the lowest gear is operated to increase burden torque and shift to the next gear.

Further, in this shift control device for an automatic transmission, when disengaging the current gear, the transmission torque borne by the highest gear differs depending on each shift.

For details, the gear change control device for this automatic transmission is as follows:
An electromagnetic multi-disc clutch or an electromagnetic multi-disc clutch as a transmission torque variable means can be used instead of a synchronizer provided at the highest gear ratio gear, that is, the highest gear or the lowest gear of a conventionally known synchronous gear type automatic transmission. A multi-disc clutch, which is a hydraulic multi-disc clutch, is installed.

In this shift control device for an automatic transmission, torque transmission is controlled by supplying a predetermined current to the multi-disc clutch or applying fluid pressure when shifting up or down from the current gear to the next gear. Temporarily transfer the load from the gear train of the current gear to the gear train of the highest gear or the lowest gear, and in that state, after setting the meshing of the current gear to neutral, the current to the multi-disc clutch is changed. or increasing the fluid pressure to increase the load on the highest gear or the lowest gear, thereby adjusting the engine speed to a predetermined rotation speed suitable for the next gear, and adjusting the gear of the synchronizer. Then, the gear is shifted to the next gear, and at the same time, the current or fluid pressure to the multi-disc clutch is released, and the load on the gear train of the highest gear or the lowest gear is released. It is configured as follows.

[Effect]

The speed change control device for an automatic transmission according to the present invention includes:
Since it is configured as above, it works as follows. In other words, the shift control device of this automatic transmission is capable of controlling the operation from the state of vehicle stop to the initial start, the operation from the state of vehicle running to the state of vehicle stop, and the control at downshift and upshift in each shift control. By using the variable transmission torque means built into the highest and lowest gears, it is possible to control the gear shift while the clutch remains connected, without engaging or disconnecting the clutch.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shift control device for an automatic transmission according to the present invention will be described in detail below with reference to the drawings. 1st
FIG. 1 is a block diagram showing an outline of a system for controlling a shift control device for an automatic transmission according to the present invention. The shift control device for an automatic transmission according to the present invention is applicable to the final gear, that is, the highest gear ratio gear (hereinafter referred to as the highest gear or 5th gear) and the final gear of a synchronous gear type transmission to be described later. In other words, the lowest gear ratio gear (hereinafter referred to as the lowest gear ratio or 1
Except for each electromagnetic multi-disc clutch as a transmission torque variable means used in the transmission gear (referred to as a speed change gear) and the control circuit portion for controlling it, for example,
This system has almost the same system as the automatic transmission shift control device disclosed in Japanese Patent No. 11754.

In Figure 1, the intake gas (air or mixture)
Engine 1 including a throttle valve to control the amount
is shown, and a flywheel 1a is attached to the output shaft of the engine 1. The clutch 2, such as a friction clutch, is released by a release lever 2a.
a is reciprocated by a piston rod 3a actuated by a clutch actuator 3, which therefore controls the engagement and disengagement of the clutch 2.

The clutch actuator 3 is controlled by hydraulic pressure from a hydraulic system 4. The transmission actuator 5 is provided with an electromagnetic multi-plate clutch actuator 15. The synchronous gear type transmission 6 is driven by a transmission actuator 5 to perform a gear change operation, and has an input shaft or input shaft 6a connected to the clutch 2, a drive shaft or output shaft 6b, and a gear position. (gear position).

The select lever 7 is operated by the driver,
"N" range (neutral position), "D" range (automatic shift), "1" range (1st speed), "2" range (2nd speed)
Each range of "3" range (3rd speed) and "R" range (reverse) can be selected by the lever position of the select lever 7, and a selection signal SP indicating the selected range is output by the select sensor 7a. be done.

The rotation sensor 8a detects the rotation speed of the input shaft 6a. The vehicle speed sensor 8b is for detecting the vehicle speed from the rotational speed of the drive shaft 6b. The engine rotation sensor 10 is for detecting the rotation speed of the engine 1 by detecting the rotation speed of the flywheel 1a.

The electronic control device 9, which is composed of a microcomputer, includes a processor 9a that decodes and executes instructions in the computer, that is, performs arithmetic processing, and a read-only memory or ROM 9 that stores control programs for controlling the transmission 6 and clutch 3.
b, an output port 9c, an input port 9d, and a random access memory for storing calculation results, etc.
It consists of a RAM 9e and an address/data bus, ie, BUS 9f, that connects them.

The output port 9c is connected to the clutch actuator 3, the hydraulic system 4, the transmission actuator 5, and the electromagnetic multi-plate clutch actuator 15, and receives drive signals CDV, PDV, ADV,
Outputs CAV and CBV. On the other hand, input port 9
d is the various sensors 6c, 7a, 8a, 8 mentioned above.
b, 10, as well as detection signals 11a and 12a from the accelerator pedal 11 and the brake pedal 12.

The accelerator pedal 11 has a sensor 11a (potentiometer, etc.) that detects the amount of depression of the accelerator pedal 11, and the brake pedal 12 has a
It has a sensor 12a that detects the amount of depression of the brake pedal 12.

Next, an example of the mechanism of the synchronous gear type transmission 6 used in the present invention will be described in detail with reference to FIGS. 5, 6, and 7.

FIG. 5 is a cross-sectional view of a main part of a synchronous gear type transmission 6 according to the present invention, in which a first speed gear train 1M, a second speed gear train 2M, Each gear train including a third speed gear train 3M, a fourth speed gear train 4M, and a fifth speed gear train 5M are installed in series.

The input shaft 6a is integrally attached to a clutch plate of the clutch 2, such as a friction clutch, and rotates together with the clutch plate. A known synchronizer D ₂ is provided between the first speed gear train 1M and the second speed gear train 2M;
Synchronizers D ₃ and D ₄ are also installed between the third-speed gear train 3M and the fourth-speed gear train 4M, and their operations are similar to those conventionally known. Electromagnetic multi _- plate clutches C ₁ and C 5 are provided on each side of the 1st speed gear train 1M and the 5th speed gear train 5M, and the 1st speed gear is controlled by each electromagnetic multi-plate clutch C ₁ and C ₅ . It is configured to connect and disconnect power transmission between the train 1M and the output shaft 6b, and between the 5th speed gear train 5M and the output shaft 6b.

FIG. 6 shows an enlarged view of the main parts of the mounting portions of the electromagnetic multi-plate clutches C ₁ and C ₅ . In Figure 6, 1
An outer disk 20 attached to a part of the speed gear train 1M or a part of the 5-speed gear train 5M and an inner disk 21 attached to the output shaft 6b are connected to a coil 22 and an armature 23 (electromagnetic multi-plate clutch actuator 1).
5) Due to the electromagnetic attraction effect, frictional contact occurs and torque is transmitted.

The torque transmission force of electromagnetic multi-plate clutches C ₁ and C ₅ is
As shown in FIG. 7, the currents increase in proportion to the currents CB and CA applied to the coil 22. These electromagnetic multi-plate clutches C ₁ and C ₅ are connected to the processor 9
According to the signals CBV and CAV from a, predetermined currents CB and CA are applied to the electromagnetic multi-disc clutch actuators 15 of the electromagnetic multi-disc clutches C ₁ and C ₅ to increase, decrease, and interrupt the required torque transmission. be.

That is, for example, when torque is currently being transmitted by the second gear train 2M, the processor 9a
gives a shift up signal, the signal
CAV starts energizing electromagnetic multi-plate clutch _C5 . As the current CA gradually increases, it is gradually transferred to the fifth speed gear train 5M due to the relationship of the reduction ratio with the fifth speed gear train 5M. As a result, the gear meshing load on the synchronizer D ₂ is reduced, making it easier for the gear to disengage.At a certain point, the processor 9a issues a transmission actuator drive signal ADV, and the synchronizer _D2 disengages the gear. This will result in a neutral state.

The current to the electromagnetic multi-plate clutch _C5 further increases,
When the load on the 5th speed gear train 5M further increases, 5
Since the reduction ratio of the speed gear train 5M is small, the rotation speed of the input shaft 6a decreases. When the rotational speed has decreased to a predetermined value, the processor 9a again issues the transmission actuator drive signal ADV, and the synchronizing device for the next speed gear train is smoothly shifted into gear. At the same time, the current supply to the electromagnetic multi-plate clutch _C5 is cut off, so that the clutch is released and all torque is transmitted by the next gear train.

A similar operation is repeated when shifting up from 3rd gear to 4th gear. Further, when shifting from the 4th gear to the 5th gear, this is achieved by fully connecting the electromagnetic multi-disc clutch _C5 . Furthermore, during downshifting, the electromagnetic multi-plate clutch _C1 operates in place of the electromagnetic multi-disc clutch _C5 , and other operations are performed in the same manner.

Next, the operation of the block diagram of the shift control device for an automatic transmission according to the present invention shown in FIG. 1 will be explained.

[1] First, when the select lever 7 is operated to the "D" range and the selection signal SP for the "D" range is input from the position sensor 7a to the input port 9d, the processor 9a reads it via the BUS 9f and stores it in the RAM 9e. Then, the drive signal ADV is outputted from the output port 9c to the transmission actuator 5, driving the transmission actuator 5 and shifting the transmission to the first speed.

[2] Next, the processor 9a receives the gear position signal GP from the gear position sensor 6c. Based on this position signal GP, the processor 9a detects that the transmission 6 has actually been shifted to 1st speed, and
Store it in 9e as TCS.

[3] Next, the processor 9a sends the clutch drive signal CDV to the clutch actuator 3 through the output port 9c, and the clutch actuator 3 gradually moves the piston rod 3a to the left, and releases the release lever 2a. gradually drive to the left. As a result, the amount of engagement of the clutch 2 changes as indicated by reference numeral a in FIG. 3, and the clutch 2 changes from a released state to a half-clutch state to a connected state. This causes the vehicle to start. Note that the symbol b in Fig. 3
shows the reverse state, that is, from a connected state to a half-clutch state to a released state.

[4] From now on, the processor 9a is the vehicle speed sensor 8.
The processor 9a periodically receives a detection signal (detection pulse) WP from the input port 9d, and calculates the vehicle speed V and stores it in the RAM 9e.
a through the input port 9d, and the RAM 9
The vehicle speed SP and the amount of depression are stored in e and as part of the program in ROM9b.
Find the gear position from the shift map SM corresponding to AP. That is, as shown in FIG. 2, the ROM 9b stores a shift map SM corresponding to the vehicle speed SPD and the depression amount AP as a table.

In FIG. 2, symbols I1, 2, 3,
4 and V5 indicate each gear stage of 1st, 2nd, 3rd, 4th, and 5th gears, where the solid line shows the boundary line between the gear stages at the time of upshifting, and the dotted line shows the boundary line between the gear stages at the time of downshifting. Then, the next gear TC1 is determined from the depression amount AP and the vehicle speed SP.

[5] Next, the processor 9a reads the currently selected gear stage stored in the RAM 9e.
The TCS is compared with the gear position for which the TCS was calculated, and if they are the same, processing proceeds without using the drive signal ADV, and if they are different, it is determined that the gear position requires an upshift or a downshift. If there is a shift up,
In order to perform a gear shift operation to the determined gear position, the process described below is performed using the flowchart shown in FIG. 4A. Further, in the case of downshifting, in order to perform a gear shift operation to the determined gear position, a process described below is performed, which will be explained using the flowchart of FIG. 4B.

First, the processing of the gear change operation at the time of shift up will be explained. [1] When the processor 9a recognizes the gear change command to shift up, the processor 9a outputs the electromagnetic multi-disc clutch drive signal CAV to the electromagnetic multi-disc clutch actuator 15. Send via port 9c. The electromagnetic multi-disc clutch C ₅ is provided at the highest speed gear, that is, the 5th gear, of the synchronous gear type transmission 6, and a gradually increasing current CA is applied to the electromagnetic multi-disc clutch C ₅ according to the signal. Ru. As the current increases gradually (DCA), the torque transmission amount (TP) of the electromagnetic multi-disc clutch _C5 increases, and the torque transmission amount value TP is stored in the RAM 9e of the processor 9a via the input port 9d. . When the processor 9a recognizes that the transmission torque TP of the electromagnetic multi-plate clutch _C5 has reached a predetermined amount and the load on the gear train of the current gear has become smaller than the predetermined value in the ROM 9b, the processor 9a A drive signal ADV is sent to the shift actuator in the drive via the output port 9c, and the gear engagement of the current gear is set to neutral.

[2] The processor 9a is a gear position sensor 6c
It is detected from the gear position signal GP that the detection signal is turned on, and it is detected that the transmission 6 has actually entered the neutral state.

[3] In parallel, the processor 9a
At the same time as reading the next gear TC1 of e, the gear ratio i at the next gear and the gear ratio I _f at the final gear are read.
Read from ROM9b, vehicle speed V in RAM9e
The following calculation is performed between TC1 and TC1 to determine the optimum engine speed _N1 for shifting to the next gear TC1. That is, N ₁ =V·i· _if /R (R is the radius of the tire) and the value N ₁ is stored in the RAM 9e.

[4] The current CA supplied to the electromagnetic multi-disc clutch C ₅ continues to increase gradually, and therefore its transmitted torque, or burden torque, also increases, so the rotational speed of the engine 1, that is, the rotational speed N ₀ of the input shaft 6a, increases. It goes down. The processor 9a receives the detection pulse IP from the rotation sensor 8a via the input port 9d, calculates the rotation speed _N0 of the input shaft 6a from this, and
Store in RAM9e.

[5] Next, the processor 9a reads the RAM 9e
The rotation speed N ₁ of the input shaft 6a and the rotation speed N ₀ of the input shaft 6a are read out and N=N ₀ −N ₁ is calculated, and the setting is made taking into account the capacity of the synchronizer, the minimum allowable shift shock, etc. Setting allowable rotation difference △N
Read from ROM9b, difference rotation speed N and △N
Compare the size with. △N is set for each gear, and the processor 9a selects the optimum △N according to the conditions.
Select.

[6] When the processor 9a determines that N<△N, that is, N ₀ −N ₁ <△N, by comparing the two described above, the processor 9a outputs the drive signal ADV of the transmission actuator 5 again via the output port 9c. send out.
As a result, the transmission 6
A shift drive is performed, and the gear is shifted to the next gear.

[7] The processor 9a is a gear position sensor 6c
A signal for recognizing the detection signal from the gear position detection signal GP input through the input port 9d, confirming the shift drive, and cutting off the electromagnetic multi-disc clutch drive current from the output port 9c, that is, making CA zero. , release the load on electromagnetic multi-disc clutch _C5 , and stop the shift drive.

[8] As a result, the transmission 6 has been synchronized to a higher speed gear, and the vehicle is running in this state, and the processor 9a is
The current gear TCS in the RAM 9e is replaced with the next gear TCI, and the gear shifting operation ends.

Next, a description will be given of processing for a gear change operation during downshifting. Processing for a gear change operation during a downshift is substantially similar to the process for a gear change operation during an upshift, and is performed as follows.

[1] When the processor 9a recognizes a speed change command to downshift, the processor 9a sends an electromagnetic multi-disc clutch drive signal CAV to the electromagnetic multi-disc clutch actuator 15 via the output port 9c. This signal causes a gradually increasing current CA to be applied to the electromagnetic multi-plate clutch _C5 . With the gradual increase in current DCA, the torque transmission amount (TP) of the electromagnetic multi-plate clutch _C5 increases, and the value of the torque transmission amount increases.
TP is connected to the processor 9 via the input port 9d.
It is stored in the RAM 9e of a. processor 9a
The transmission torque TP of the electromagnetic multi-plate clutch _C5 reaches a predetermined amount, and the load on the gear train of the current gear is reduced.
When the processor 9a recognizes that the value has become smaller than the predetermined value in the ROM 9b, the processor 9a sends a drive signal ADV to the shift actuator in the transmission actuator 5 via the output port 9c, and sets the gear engagement of the current gear to neutral. do.

[2] The processor 9a is a gear position sensor 6c
It is detected that the detection signal is turned on from the gear position signal GP, and the gear of the synchronizer is pulled out without disengaging clutch 2 while electromagnetic multi-disc clutch _C5 is energized. Next, it is detected that the gear is actually disengaged and the transmission 6 is in the neutral state. Here, the current CA to the electromagnetic multi-disc clutch _C5 is reduced to zero, that is, the current supply to the electromagnetic multi-disc clutch _C5 is cut off. Furthermore, an electromagnetic multi-plate clutch provided in the first gear train 1M of the lowest gear, that is, the first gear.
By energizing _C1 and causing current CB to flow, the input shaft 6a
Increase the rotation speed N ₀ .

[3] In parallel, when the select switch is turned on, the processor 9a changes to the next gear of the RAM 9e.
At the same time as reading TC1, the gear ratio i at the next gear
and the gear ratio i _f at the final gear (1st gear)
Read from ROM9b, vehicle speed V in RAM9e
The following calculation is performed between TC1 and TC1 to determine the optimum engine speed _N1 for shifting to the next gear TC1. That is, N ₁ =V·i· _if /R (R is the radius of the tire) and the value N ₁ is stored in the RAM 9e.

[4] Here, the current CB supplied to the electromagnetic multi-plate clutch C ₁ continues to gradually increase (current increment DCB), and the transmitted torque, that is, the burden torque, also increases, so that the rotational speed of the engine 1, that is, The rotational speed N ₀ of the input shaft 6a increases. The processor 9a receives the detection pulse IP from the rotation sensor 8a.
is received through the input port 9d, from which the rotation speed _N0 of the input shaft 6a is calculated and stored in the RAM 9e.

[5] The processor 9a determines the rotation speed of the RAM 9e.
Read out N ₁ and the rotation speed N ₀ of the input shaft 6a, △N
In addition to calculating =N ₁ - N ₀ , the setting allowable rotational difference △N, which is set in consideration of the capacity of the synchronizer and the minimum allowable shift shock, etc., is calculated in ROM9.
Read from b, compare the size of N ₁ and N ₀ ,
to decide. ΔN is set for each gear stage, and the processor 9a sets the optimum ΔN according to the conditions.

[6] When the processor 9a determines that N ₁ −N ₀ <ΔN by comparing the two, it sends out the drive signal ADV of the transmission actuator 5 again through the output port 9c. Thereby, the transmission 6 is driven to shift via an appropriate hydraulic circuit, and the gear is shifted to the next gear.

[7] The processor 9a is a gear position sensor 6c
The detection signal is recognized from the gear position detection signal GP input through the input port 9d, and the shift drive is confirmed. At the same time, a signal for cutting off the electromagnetic multi-plate clutch drive current is sent from the output port 9c, and the electromagnetic multi-plate clutch is Release the load on clutch _C1 , that is, make CB zero, and complete the shift drive.

[8] As a result, the transmission 6 has been synchronized to a lower gear, and the vehicle runs in this state, and the processor 9a
The current gear TCS of 9e is replaced with the next gear TCI, and the gear shifting operation is completed.

FIG. 4C shows a flowchart of a conventional system. This flowchart is shown in comparison with the flowcharts for upshifting and downshifting according to the present invention shown in FIGS. 4A and 4B.

Although one embodiment of the shift control device for an automatic transmission according to the present invention has been described above in detail, the present invention is not necessarily limited to the above configuration. For example, it is not limited to electromagnetic multi-plate clutches,
The clutch may be of any type as long as it can vary the transmission torque, and it goes without saying that a friction clutch, a fluid pressure clutch, a fluid pressure multi-plate clutch, etc. can be applied. Various design changes can be made within the scope of the technical concept defined by the above matters.

〔Effect of the invention〕

The speed change control device for an automatic transmission according to the present invention includes:
The configuration as described above has the following effects. That is, the speed change control device of this automatic transmission is
By controlling the variable transmission torque means installed in the highest and lowest gears, the clutch can be connected without disengaging the clutch during upshifting or downshifting of a synchronous gear type automatic transmission. Since the shift operation can be performed without changing the state, the time required for clutch release and clutch engagement can be shortened compared to conventional ones, and since the clutch is always connected, the problem of time lag during shifting is eliminated. This prevents torque loss during both downshifting and upshifting, and also prevents shocks associated with clutch engagement.

Therefore, smooth gear shifting is possible without giving the driver a feeling of weakness or stalling. Also, regarding the structure of the automatic transmission's shift control device itself,
Among the configurations of conventional synchronous gear type automatic transmissions, the synchronizer for the final gear, that is, the highest gear ratio gear, or for the lowest gear ratio, that is, the first gear, is equipped with an electromagnetic multi-disc clutch or the like. This modification has the great effect that all the other parts can be used in common by simply replacing the transmission torque variable means.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing an example of a system in which the present invention is implemented, Fig. 2 is an explanatory diagram of a shift up for speed change operation used in implementing this invention, and Fig. 3 is an explanatory diagram of clutch operation. FIG. 4A is a flowchart showing the operation of the automatic transmission's transmission control device during upshifting, and FIG. 4B is a flowchart showing the operation of the automatic transmission's transmission control device during downshifting. C is a flowchart showing the operation of a conventional automatic transmission shift control device, FIG. 5 is a sectional view of main parts of a synchronous gear type automatic transmission according to the present invention, and FIG. 6 is a mounting portion of an electromagnetic multi-plate clutch. and FIG. 7 are diagrams showing the characteristics of the electromagnetic clutch. DESCRIPTION OF SYMBOLS 1... Engine, 2... Clutch, 5... Transmission actuator, 6... Transmission, 6a... Input shaft, 6b... Output shaft, 1M, 2M, 3M, 4M,
5M...Gear train at each gear stage of the transmission, D ₂ ,
_D3 , _D4 ...Synchronizer, _C1 , _C5 ...Electromagnetic multi-plate clutch (transmission torque variable means), 15...Electromagnetic multi-plate clutch actuator.

Claims (1)

[Scope of Claims] 1. A transmission torque variable means is installed in each of the highest speed gear and the lowest speed gear, and at the time of shifting, the transmission torque variable means installed in the highest speed gear is first actuated to adjust the transmitted torque. The transmission is brought into a neutral state by disengaging the current gear while partially bearing the load, and then, at the time of upshifting, increasing the load torque of the transmission torque variable means attached to the highest gear. When downshifting, the variable transmission torque means installed in the highest gear is released, and the variable transmission torque means installed in the lowest gear is activated to reduce the load. A shift control device for an automatic transmission, characterized in that the shift control device controls the shift to the next gear by increasing torque. 2. The automatic transmission according to claim 1, wherein the transmission torque borne by the highest gear when disengaging the current gear differs depending on each shift. Machine speed control device.