JPH0375774B2 - - Google Patents

Description

[Detailed Description of the Invention] 〓Field of Industrial Application〓 The present invention relates to an automatic transmission that can automatically change the gear ratio, and particularly relates to an automatic transmission that can change the gear ratio automatically.
The present invention relates to an automatic transmission in which a calculation means selects a gear to be used in accordance with an accelerator opening degree, etc., and an actuator engages the selected gear to obtain a predetermined gear ratio.

〓Prior Art〓 Conventionally, a transmission has been attached to an automobile engine in order to change the rotational speed of the engine to an appropriate value. This transmission selects the gear to be used depending on the speed change operation of the driver, converting the engine speed to an appropriate value and transmitting it to the drive wheels. . However, with such conventional transmissions, the driver has to operate the gear shift lever depending on the driving condition of the vehicle, which makes driving operations extremely complicated.

To overcome these drawbacks, automatic transmissions have been proposed. In this automatic transmission, a calculation means such as a microcomputer selects the gear to be used depending on the vehicle speed, accelerator opening, etc., and the actuator meshes the selected gear to automatically set a predetermined gear ratio. It was designed to obtain By equipping an automobile with such an automatic transmission, the driver hardly needs to operate a lever to change gears.

However, vehicles equipped with such automatic transmissions have difficulty starting on hills. Generally, in order to start on a hill, the clutch is first slipped to balance the gravitational acceleration applied to the vehicle and the torque applied to the drive wheels.
In this state, the accelerator pedal is pressed down to start the vehicle, but the automatic transmission cannot perform this delicate half-clutch operation, making it impossible to start smoothly on a slope. Ta.

〓Object of the Invention〓 The present invention has been made in view of the above-mentioned problems, and provides an automatic transmission that controls the amount of clutch slip and enables smooth hill start. The purpose is to provide the following.

〓Structure of the Invention〓 The present invention selects a gear to be used by a calculation means according to vehicle speed, accelerator opening degree, etc.
In an automatic transmission in which an actuator engages the selected gears to obtain a predetermined gear ratio, the brake of the braking device is necessary to operate the braking device and maintain the vehicle in a stopped state. A means for detecting torque and a means for detecting a slip amount of the clutch are provided, and the vehicle is stopped by slipping the clutch such that a torque equal to the brake torque detected by the means for detecting brake torque is generated. This invention relates to an automatic transmission characterized by maintaining the vehicle in a stopped state, and by slipping the clutch in this way and maintaining the vehicle in a stopped state, it is possible to easily start the vehicle on a slope. It is something.

〓Example〓 The present invention will be described below with reference to an illustrated example.
FIG. 1 shows an engine for a motor vehicle equipped with an automatic transmission according to an embodiment of the present invention, and this engine is composed of a diesel engine 10 for a truck. The diesel engine 10 is equipped with a fuel injection pump 11, which sequentially supplies fuel to each cylinder of the engine 10.
The fuel injection pump 11 is driven by the engine 10 via a timer 12, and the timing of fuel injection is adjusted by the timer 12. Furthermore, the fuel injection pump 11 is equipped with a mechanical governor 13, and the governor 13 is adapted to adjust the amount of fuel to be injected.

A flywheel housing 14 is provided on the rear side of the engine 10, and this housing 1
A flywheel fixed to the end of the crankshaft is housed within the crankshaft. A clutch (not shown) is provided on the back side of the flywheel, and a transmission 15 is attached to the back side of the flywheel housing 14 so as to be connected to this clutch. This transmission 15 converts the rotational speed of the engine 10 into an appropriate value and transmits it to the drive wheels via a propeller shaft 16.

The transmission 15 constitutes an automatic transmission, and a shift actuator 17 and a selection actuator 18 are provided above the transmission. Furthermore, a clutch actuator 19 is mounted on the outer surface of the casing of the transmission 15 for controlling the connection and disconnection of a clutch mounted on the rear side of the flywheel. Furthermore, a fuel control actuator 20 is provided at the front end of the fuel injection pump 11 to adjust the position of the control rack and control the amount of fuel supplied. These four actuators 17, 18,
19 and 20 are adapted to be driven based on instructions from the microcomputer 21 via respective driving means.

The input side of the microcomputer 21 is connected to a control box 22. This control box 22 is the conversion lever 2.
It has 3. Furthermore, this microcomputer 21 is connected to an accelerator sensor 25 that detects the opening degree of the accelerator or the amount of depression of the accelerator pedal 24. Further, the microcomputer 21 is connected to a vehicle speed sensor 26, an engine rotation sensor 27, a rack sensor 28, and a clutch sensor 29, respectively.

The vehicle speed sensor 26 is provided on the side of the transmission 15.
The vehicle speed is detected based on the rotational speed on the output side of the engine. Further, the engine rotation sensor 27 is attached to the front side of the engine 10 and is adapted to detect the rotation speed of the engine 10. Furthermore, the rack sensor 28 is connected to the actuator 20.
It is attached to the tip side of the fuel injection pump 1.
The position of the control rack No. 1 is detected. A clutch sensor 29 is attached to the distal end of the clutch actuator 19, and is adapted to detect the connected and disconnected states of the clutch.

Furthermore, a microcomputer 21 constituting the calculation means of the automatic transmission according to this embodiment
The input side of is connected to a pressure sensor 31 that detects the pressure in the brake cylinder 30 of the service brake. This pressure sensor 31 is configured to generate a detection output when the brake pedal is depressed and the pressure in the cylinder 30 increases, and constitutes a brake sensor. Further, a torque sensor 32 is connected to the input side of the microcomputer 21. The torque sensor 32 is installed between the tire of the drive wheel and the brake drum or disk, and measures the amount of torque required to stop the vehicle when the service brake is activated.

Next, the operation of the automatic transmission configured as described above will be explained. This operation is performed based on a program preset in the microcomputer 21, and when the shift lever 23 of the control box 22 is in the automatic position, the shift operation is automatically performed. There is. On the other hand, the gear shift lever 23
is in the manual position, the manually selected gear shift operation is performed by the actuators 17,
18.

To give an overview of the automatic shift operation, the microcomputer 21 detects whether the shift lever 23 of the control box 22 is in the automatic position, and if it is in the automatic position, the accelerator pedal 24 is depressed at regular intervals. The accelerator sensor 2 detects the amount or accelerator opening degree and the vehicle speed.
5 and the vehicle speed sensor 26. Further, the microcomputer 21 reads the map stored in its memory, and based on this map, calculates whether automatic gear shifting is possible. If automatic gear shifting is possible, gear shifting is performed to obtain the calculated gear ratio. On the other hand, if it is determined that automatic gear shifting is not possible, gear shifting is not performed.

The specific operation of automatic gear shifting is such that the shift actuator 17 and the select actuator 18 are operated based on a command from the microcomputer 21 via a drive means (not shown), and the gears of the transmission 15 are selected. The selected gears of the transmission 15 are thereby brought into mesh. Therefore, a predetermined gear ratio can be obtained in this way. During this shift operation, the actuator 19 switches the clutch to the disconnected state, and synchronizes with the end of the shift operation to bring the clutch back into the connected state.

Further, according to the automatic transmission according to this embodiment, the vehicle can be maintained in a stopped state even on a sloped road surface such as a slope without depressing the brake pedal. In this operation, when the service brake is applied, the torque sensor 32 measures the torque required to stop the vehicle, and the actuator 19 slips the clutch so that the above torque is generated. This is achieved by holding it in place, and it is operated according to the flowchart shown in FIG.

The microcomputer 21 first uses the brake sensor 31 to activate the service brake for a certain period of time.
For example, it is detected whether the operating state is maintained for two seconds or more. If the service brake operating time exceeds a certain level, the torque sensor 3
2 reads the amount of torque required for the service brake to stop the vehicle. When the foot is released from the brake pedal, the clutch is slipped to maintain the vehicle stopped.

That is, the microcomputer 21 determines whether the sensed torque is forward or backward, and in the case of reverse, sets the gear of the transmission 15 to the forward side, and in the case of forward, shifts the gear of the transmission 15 to the forward side. Put it in retreat. This movement is accomplished by actuators 17,18. Thereafter, the clutch is engaged by the clutch actuator 19 until the above-mentioned sensed torque is generated, and the operation of the actuator 19 is stopped in a half-clutch state where the torque matches, and this state is maintained. Do it like this. Therefore, the vehicle remains stationary with the torque applied to the drive wheels by this half clutch. This state will continue until the next time the accelerator pedal is depressed, and the vehicle will remain stationary. Furthermore, if a wet type clutch is used as the clutch, it is very advantageous not only because it can be easily slipped in a half-clutch state, but also because it hardly wears out even if it slips.

As described above, according to the automatic transmission according to this embodiment, when the brake pedal is released after being depressed for a certain period of time, the service brake is used to maintain the vehicle in a stopped state with torque. The same torque is generated by slipping the clutch and makes it possible to maintain the vehicle at a standstill. Since the vehicle can be maintained in a stopped state with the clutch slipped in this way, it is possible to start the vehicle on a hill easily and immediately by depressing the accelerator pedal. There is no need to operate levers or other pedals at all. Therefore, with this configuration, an automatic transmission that can smoothly start the vehicle on a slope can be obtained.

Although the present invention has been described above with reference to an illustrated embodiment,
The present invention is not limited to the above embodiments, and various modifications can be made based on the technical idea of the present invention. For example, the torque sensor 32 in the above embodiment is configured to detect the torque that maintains the vehicle in a stopped state when the service brake is activated, but instead of having such a configuration, it is possible to detect the torque that maintains the vehicle in a stopped state when the service brake is activated. In some cases, the torque that maintains the vehicle in a stopped state may be detected. In this case, a torque sensor may be provided between the drive wheels and the propeller shaft.

〓Configuration of the Invention〓 As described above, the present invention detects the brake torque of the braking device necessary to operate the braking device and maintain the vehicle in a stopped state, and also generates a torque equal to this brake torque. The clutch is kept in a stopped state by slipping the clutch. Therefore, it is possible to start on a slope by depressing the accelerator pedal in this stopped state, and the vehicle can be started smoothly without moving backward when starting on a slope. Moreover, since this kind of operation is possible by simply installing a sensor that detects the brake torque of the braking device in a conventional mechanical automatic transmission, a simple configuration allows the function of starting on a hill to be added to a mechanical automatic transmission. Can now be given to Shion.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an automatic transmission according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the creep operation of this automatic transmission. In addition, in the symbols used in the drawings, 15...transmission, 17...shift actuator, 18...select actuator, 19...
...Clutch actuator, 21...Microcomputer, 25...Accelerator sensor, 26...
Vehicle speed sensor, 31... Brake sensor, 32...
It is a torque sensor.

Claims (1)

[Claims] 1. In an automatic transmission in which a calculation means selects a gear to be used according to vehicle speed, accelerator opening, etc., and an actuator engages the selected gear to obtain a predetermined gear ratio. and means for detecting the brake torque of the braking device necessary for operating the braking device to maintain the vehicle in a stopped state, and means for controlling the slip amount of the clutch, and the means for detecting the braking torque 1. An automatic transmission characterized in that the clutch is kept in a stopped state by slipping a clutch so as to generate a torque equal to the detected brake torque.