JPH0517973B2 - - 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, and an actuator engages the selected gear to obtain a predetermined gear ratio.

<Prior Art> In order to change the rotational speed of an automobile engine to an appropriate value, a transmission has conventionally been attached to the engine. This transmission selects the gear to be used according to the driver's gear change operation, and changes the engine speed to an appropriate value and transmits 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, if such an automatic transmission is installed in a truck, for example, the vehicle will always start in second gear regardless of the slope of the road surface, so when the driver switches to the drive range and depresses the accelerator pedal, the transmission will start automatically. This is because the speed is automatically switched to second speed. Therefore, for example, when starting on an uphill slope, there is a possibility that the vehicle will move backwards due to insufficient traction force. That is, automatic transmissions have the disadvantage that the gear ratio of the transmission cannot be arbitrarily selected in order to select the traction force depending on the road surface condition.

〓Object of the Invention〓 The present invention has been made in view of the above-mentioned problems, and provides an automatic transmission that can smoothly start on a place where a large starting torque is generated, such as on an uphill slope. The purpose is to

〓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 meshes the selected gears to obtain a predetermined gear ratio, the braking state detecting means detects that the braking means is in an operating state; and the braking state detecting means means for fixing the gear ratio of the transmission at first gear until a predetermined vehicle speed is reached when starting the vehicle while loosening the braking by the braking means whose operating state is detected by the vehicle. This relates to the automatic transmission, which is unique in that it generates sufficient torque even when starting up on an uphill slope.

〓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 is configured to change the rotational speed of the engine 10 to an appropriate value and transmit 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 gear shift 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. Furthermore, 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 the service brake sensor 30. The service brake sensor 30 is composed of a pressure switch, and is designed to detect whether or not the service brake is operated based on the pressure inside the brake cylinder 31. Furthermore, the input side of the microcomputer 21 is connected to a parking brake switch 32 that detects whether or not the parking brake is activated.

Next, the operation of this automatic transmission configured as described above will be explained. This operation is performed based on a program preset in the microcomputer 21.
When the shift lever 23 of the control box 22 is in the automatic position, the shift operation is automatically performed. On the other hand, when the shift lever 23 is in the manual position, the manually selected shift operation is performed by the actuator 1.
7 and 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 selection 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 clutch is temporarily switched to the disconnected state by the actuator 19, and then the clutch is brought into the connected state again in synchronization with the end of the shift operation.

Furthermore, according to the automatic transmission according to this embodiment, when starting on a steep uphill slope, sufficient starting torque is applied to the drive wheels to prevent the vehicle from moving backwards, and for this purpose, the service brake Alternatively, when starting the vehicle while loosening the parking brake, the gear ratio of the transmission 15 is fixed at 1st speed. This state of being fixed at 1st gear continues until the vehicle speed reaches the maximum traction point at the 1st gear ratio, after which it automatically shifts to the drive range and resumes normal driving. That's what I do.

To explain this operation based on the flowchart shown in FIG. 2, the microcomputer 21 reads the output of the control box 22, the output of the parking brake switch 32, the output of the service brake switch 30, and the output of the accelerator sensor 25. . Based on the output of the control box 22, it is determined whether the vehicle is in the drive range, and if the vehicle is in the drive range, the parking brake switch 32 determines whether the parking brake is ON. When the parking brake switch 32 is OFF, the detection output of the service brake switch 30 is further read to determine whether the service brake is being operated.

Then, the accelerator sensor 25 detects that the accelerator pedal 24 is depressed while the parking brake is being applied, or the pressure switch 30 detects that the service brake is being applied, and the accelerator pedal 24 is detected by the accelerator sensor 25, the microcomputer 21 determines that the vehicle is about to start on an uphill slope, and switches the gear ratio of the transmission 15 to 1st speed. Fixed in state.

Next, the microcomputer 21 reads the vehicle speed using the vehicle speed sensor 26, and determines whether this vehicle speed is above a certain value. This constant vehicle speed is the vehicle speed at which the maximum traction force is exerted at the first gear ratio, and when this vehicle speed is reached, the drive range is switched and normal automatic transmission operation is performed. I'm trying to make it happen.
Therefore, after this, a normal shift-up operation is performed.

According to the automatic transmission according to this embodiment, when the vehicle starts by depressing the accelerator pedal 24 while releasing the service brake or parking brake, the transmission 15 is fixed at first gear. It's summery. Therefore, it is possible to transmit sufficient torque to the driving wheels, and even when starting on a steep slope, it is possible to prevent the vehicle from moving backwards, and the starting can be performed smoothly.
It becomes possible to provide automatic transmission with excellent safety. The system automatically shifts to the drive range when the vehicle speed reaches a certain value, so the function of the automatic transmission is not impaired.

<Effects of the Invention> As described above, the present invention includes a braking state detecting means for detecting that the braking means is in an operating state, and a braking device whose operating state is detected by the braking state detecting means. A means is provided for fixing the gear ratio of the transmission at first speed until a predetermined vehicle speed is reached when the vehicle starts moving while easing the speed.

Therefore, according to the present invention, when the vehicle is started on an uphill slope and the vehicle is started while loosening the braking by the braking means, the braking state detection means detects that the braking means is in a braking state. As a result, the gear ratio of the transmission is fixed at 1st speed until a predetermined vehicle speed is reached. Therefore, when starting on an uphill slope, sufficient torque can be transmitted to the drive wheels through the transmission that is fixed in first gear. In addition to effectively and reliably preventing the vehicle from rolling backwards,
This makes it possible to start smoothly on uphill slopes.
Furthermore, since such a starting operation is automatically performed by the braking state detection means, driving operation becomes extremely easy and it becomes possible to provide an automatic transmission with high safety.

[Brief explanation of the drawing]

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 starting 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, 30...Service brake sensor,
32... Parking brake switch.

Claims (1)

[Scope of Claims] 1. Gears to be used are selected by a calculating means according to vehicle speed, accelerator opening degree, etc., and the selected gears are meshed by an actuator to obtain a predetermined gear ratio. The automatic transmission includes a braking state detecting means for detecting that the braking means is in an operating state, and a braking state detecting means for detecting that the braking means is in an operating state; An automatic transmission comprising: means for fixing the gear ratio of the transmission to first speed until a predetermined vehicle speed is reached.