JPH0747638Y2 - Shift control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a shift control device for an automatic transmission, and more particularly, to a prescribed hold stage lock when failure information of the transmission is detected during traveling at an automatic shift stage. The present invention relates to a shift control device for an automatic transmission that performs the above as a fail safe.

(Prior Art) A transmission is arranged in a power transmission system of a vehicle, and an automatic transmission is often used which can perform a shift control thereof without switching a clutch.

This automatic transmission is provided with a fluid coupling, a planetary gear, and a brake member and a clutch member that switch the arrangement of the planetary gears. Among these, the brake member and the clutch member are switched through a hydraulic circuit with a switching valve. . Moreover, this switching valve is a plurality of solenoid valves of the spool valve type, and these are switched so as to secure an appropriate shift speed designated by the control means of the shift control device.

When the shift position is in the D range (automatic shift range), the shift control device for an automatic transmission of this type takes in the rotational speed information of the transmission output shaft and the load information of the engine, and selects an appropriate shift speed corresponding to both values. Is calculated based on the shift selection map (one example of which is shown in FIG. 4). Then, in order to secure the arrangement of the planetary gears according to the appropriate shift speed, a switching signal for switching the brake member, the clutch member and the like is output to each solenoid valve side via each drive circuit.

By the way, the shift control device of the automatic transmission calculates the difference between the engine speed and the output shaft speed of the transmission, and it is determined that the value exceeds a specified speed which is considered to be a transmission failure. Then, in order to prevent the engine from overrunning immediately, there is a fail-safe function that locks the third speed hold.

(Problems to be solved by the invention) However, when a shift control device for an automatic transmission having such a fail-safe function is considered to be a transmission failure during traveling in the D range, the shift control device enters the third speed hold. , The following problems will occur.

That is, even if the driver enters the third speed hold, he / she tries to continue the traveling when it is necessary to further travel, but at this time, if the bird's wear of the transmission is actually damaged, the hydraulic pressure increases. In some cases, it may not be possible to drive. However, if there is a failure in each sensor or the harness portion thereof, the third speed running is possible. However, even in such a case, once the vehicle stopped and tried to start again, it could not start because of the 3rd speed lock, and even if it was running, it became impossible to run if it climbed uphill, causing a problem. Made of

In this way, when the 3rd speed hold is entered due to poor contact in the harness portion, etc., even if the driver selects the L range or the 2 range when restarting, these will be empty commands and 3
Since the vehicle is held at a high speed, it becomes impossible to start and run, and the problem of engine overrun is apt to occur only when trying to escape from this state.

An object of the present invention is to provide a shift control device for an automatic transmission that can start and run even when the transmission is considered to be out of order.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention takes in the output shaft rotation information of the transmission and the load information of the engine by the control means, and at the same time, establishes an appropriate shift speed corresponding to both of these information. Further, the control means switches the first and second hydraulic pressure switching valves of the hydraulic circuit of the transmission through the drive circuits in order to secure the appropriate shift stage, and the transmission is turned on. When the difference in the number of rotations of the output shaft exceeds a specified value, hold stage locking is performed to turn off both the switching signals to the first and second hydraulic pressure switching valves. In particular, the control means is When the shift position is in the specified starting range, the engine speed is equal to or lower than the specified speed, and the switching signals to the first and second hydraulic pressure switching valves are both off,
At least one of the switching signals to the first and second hydraulic pressure switching valves is turned on to hold the transmission at the specified starting stage.

(Operation) When the shift position is in the specified starting range, the engine speed is equal to or lower than the specified speed, and the switching signals to the first and second hydraulic pressure switching valves are both off, the control means controls the first and second hydraulic pressures. Since at least one of the switching signals to the switching valve is switched on to hold the transmission at the specified starting stage,
When the driver switches the shift lever to the specified starting range, the transmission can be switched to the specified starting stage.

(Embodiment) The shift control device for the automatic transmission shown in FIG. 1 is attached to the automatic transmission between the engine 1 and a drive wheel side power transmission meter (not shown).

This automatic transmission A includes a fluid coupling 2, a transmission 3, and a transmission 3
And a hydraulic switching device 4 in the lower part of the. Here, the shift control device of the automatic transmission (hereinafter simply referred to as the shift control device) includes at least a pair of solenoid valves 5 and 6 in the hydraulic switching device 4, a controller 7 as a control means for operating these valves, and It is composed of a controller 7 and a fail-safe circuit 8 connected in parallel.

The transmission 3 can switch and switch the planetary gear train in addition to the reverse and neutral N and selectively switch the gears from the first speed to the fourth speed, and includes a clutch member and a brake member for switching the planetary gear train array. A well-known structure is adopted.

The hydraulic pressure switching device 4 includes a hydraulic circuit (not shown) connected to the clutch member and the brake member in the transmission 3.
By switching the first and second solenoid valves 5 and 6 in the hydraulic circuit, the clutch member and the brake member are selectively switched between operating and non-operating.

Here, the first and second solenoid valves 5 and 6 move the planetary gear train from the first gear to the fourth gear according to the switching signal as shown in FIG.
It is configured so that the switching arrangement can be selectively performed up to the speed stage.

A main part of the controller 7 is formed by a well-known microcomputer 10, and a diode is provided on the output port side thereof.
Valve drive circuits 13 and 14 are connected via 11 and 12.

A load sensor 1 that outputs the accelerator opening amount of the engine 1 as load information to the output port of the microcomputer 10.
5, an engine rotation sensor 16 that outputs rotation speed information of the engine 1, an input rotation sensor 17 that outputs input rotation information of the transmission, an output rotation sensor 18 that outputs output rotation information of the transmission, etc. are connected. . Both rotation sensors 17 and 18 are pulse generators, one sensor 17 outputs rotation information of a kickdown brake drum (not shown), and the other sensor 18 outputs rotation information of the transmission output shaft 30.

In terms of the function of the controller 7 here, first, each information of the engine load and the engine speed is taken in and the controller 7 responds to acceleration and deceleration by using a gear selection map as shown in FIG. It functions as a shift stage calculating means for calculating an appropriate shift stage.

Further, the controller 7 has a function as a switching control means that outputs a switching signal according to the appropriate shift speed to the first and second valve drive circuits 13 and 14.

The fail-safe circuit 8 includes a1 to a9 as input side terminals and a10 and a11 as output side terminals, and a main part is formed of a logic circuit.

The terminal a1 is connected to a first rotation determination circuit 19 which outputs an ON signal when the speed is 1500 rpm or less based on the engine rotation information. The terminal a2 is connected to an L range output circuit 22 that issues an ON signal when the range is L based on the range 1 information from the inhibitor switch 21 that issues the range information of the shift lever 20.

The terminal a3 is connected to a voltage determination circuit 23 that outputs an ON output when the power supply voltage maintains a specified level. The terminal a4 is connected to a P, R, N, D range circuit 24 in which the inhibitor switch 21 turns on and outputs one of the P, R, N, D ranges.

The terminals a5 and a6 are connected to the terminals of the first and second diodes 11 and 12 on the side of the micro-computer. The L range circuit 22 and the second range circuit 25 of the inhibitor switch 21 are connected to the terminals a7 and a8, respectively. The engine speed is at terminal a9
A second rotation determination circuit 26 that outputs an on-state at 3000 rpm or less is connected.

In FIG. 1, symbol DI indicates a diode, symbol AND indicates an AND gate, symbol NOT indicates an inverter, symbol R indicates a resistance, and a symbol.

The operation of such a shift control device for an automatic transmission will be described.

While the driver is traveling with the shift lever 20 in the D range, the controller 7 calculates an appropriate shift speed from the engine load and the output shaft rotation speed, and sends a switching signal for securing the shift speed to the first and second valves. Output to the circuits 13 and 14. As a result, the first and second solenoid valves 5 and 6 are switched,
It is possible to drive by selecting and using the gear stages from 1st to 4th.

Then, the controller 7 calculates the difference between the input and output rotation information of the transmission, and when it determines that the value exceeds the failure determination value that is the specified value, the first and second solenoid valves 5, 6
Outputs an off signal for switching both to the off position.

As a result, the third speed hold is entered. Run in this state,
Eventually, when it becomes impossible to travel, for example, when the vehicle restarts or travels uphill. At this time, the driver puts the shift lever 20 in the L range and keeps the engine speed at 1500 rpm or less. As a result, the terminal a3 is turned on and the terminal a4 is turned off. This is inverted by the inverter NOT2, the subsequent AND gate AND1 is turned on, and the AND gate AND2 is also turned on.

At this time, since the engine speed is 1500 rpm and L range, both terminals a1 and a2 are on, and AND gate AND3
Is on. Therefore, AND gate AND4 is turned on,
The output terminal a10 outputs ON as a switching signal.

Similarly, one of terminals a7 and a8 is on, and at this time terminal a9 is 300
It is on at 0 rpm or less, and AND gate AND5 is on. Therefore, the AND gate AND6 also turns on and the output terminal a1
1 outputs ON as a switching signal. In this way, by keeping the shift lever 20 in the L range and the engine speed at 1500 rpm or less, it is possible to switch to the first gear, which is the starting gear, that is, to switch the starting gear manually.

After this, the first speed is maintained even if the gear is put in the 2 range.

Furthermore, the engine speed shall be maintained at 1500 rpm or more and 3000 rpm or less (see Fig. 3). In this case, the end a10 is turned off, and the gear is switched to the second gear as shown in FIG. Furthermore, if the rotation speed is increased to 3000 rpm or higher, the gear will return to the third speed.

Thus, since the controller 7 and the fail-safe circuit 8 are connected in parallel to the first and second solenoid valves 5 and 6 of the hydraulic circuit, even if the controller once outputs the output for holding the third speed, the shift lever 20 By switching to the L, 2 range and keeping the engine speed below the specified value of 1500 rpm, 3000 rpm, it is possible to secure the first and second speed stages, which are the starting stages.
You can easily start and run uphill.

(Effects of the Invention) As described above, the present invention is capable of manually switching the transmission to the starting stage by switching the shift lever to the starting range when the gear is in the hold stage, which is regarded as a transmission failure. Even if it is done, it is possible to easily start and run uphill.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a shift control device for an automatic transmission as one embodiment of the present invention, FIG. 2 is a diagram for explaining the correspondence between shift stages of a solenoid valve used in the same device and switching signals, and FIG. FIG. 4 is an explanatory view of switching of engine speed and output signal in the same apparatus, and FIG. 4 is a characteristic diagram of a shift stage calculation map used in the same apparatus. 1 ... Engine, 3 ... Transmission, 4 ... Hydraulic switching device, 5,6 ... Solenoid valve, 7 ... Controller,
8 ... Fail-safe circuit, 10 ... Microcomputer, 16 ... Engine rotation sensor, 17 ... Input rotation sensor, 18 ... Output rotation or sensor, 20 ... Shift lever.

Claims (1)

[Scope of utility model registration request] 1. A control means fetches output shaft rotation information of a transmission and engine load information, determines an appropriate shift speed in accordance with both of these information, and the control means secures the appropriate shift speed. Therefore, the first and second hydraulic pressure switching valves of the hydraulic circuit of the transmission are switched and driven through the drive circuits,
Further, if the difference in the number of rotations of the input / output shaft of the transmission exceeds a specified value, the automatic shift control is configured to perform a hold stage lock in which both the switching signals to the first and second hydraulic pressure switching valves are turned off. In the shift control device for a machine, the control means is configured such that when the shift position is within a specified starting range, the engine speed is below a specified speed, and the switching signals to the first and second hydraulic pressure switching valves are both off. A shift control device for an automatic transmission, characterized in that at least one of the switching signals to the first and second hydraulic pressure switching valves is turned on to hold the transmission at a specified starting stage.