JPS61136050A - Automatic transmission unit - Google Patents

Abstract

PURPOSE:To make it possible to smoothly start a vehicle on an ascending slope, by fixing a gear ratio at that of the first stage until a predetermined vehicle speed is attained, then the vehicle is started while the braking thereof is gradually released. CONSTITUTION:A microcomputer 21 receives output signals from a service brake sensor 30 and a parking brake switch 32 which are respectively provided to a brake cylinder 31 and a parking brake. Further, when a vehicle is started while braking by a brake means is gradually released, a gear ratio is fixed at that of the first stage until a predetermined vehicle speed is attained. With this arrangement, a sufficient torque maybe generated even upon starting on an ascending slope, etc. Accordingly, the starting of the vehicle may be smoothly made data place such as, for exmaple, ascending slope, where a large starting torque is required.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an automatic transmission that is capable of automatically changing gear ratios, and in particular, a calculation means selects the gear to be used according to vehicle speed, accelerator opening, etc., and an actuator selects the gear to be used. The present invention relates to an automatic transmission that meshes selected gears to obtain a predetermined gear ratio.

[Prior Art I] In order to change the engine speed of a vehicle to an appropriate value, a transmission has conventionally been attached to the engine. In this transmission, the gear to be used is selected in response to the driver's gear change operation, and the engine speed is changed to an appropriate value and transmitted to the drive wheels. However, with such a conventional transmission, the driver has to operate the gear shift lever depending on the driving condition of the vehicle, etc., which makes driving operations extremely complicated. Automatic transmissions have been proposed to overcome these drawbacks. In this automatic transmission, a calculation means such as a microcomputer selects the gears to be used depending on the vehicle speed, accelerator opening degree, etc., and an actuator meshes the selected gears to automatically obtain a predetermined gear ratio. This is what I did. 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. This is because the transmission is normally started in second gear, so when the driver switches to the drive range and depresses the accelerator pedal, the transmission automatically switches to second gear. Therefore, for example, when starting on an uphill slope, there is a possibility that the vehicle will run into contact due to insufficient traction force. In other words, 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. KObject of the Invention The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an automatic transmission that can smoothly start a vehicle in places where a large starting torque is generated, such as on an uphill slope. The purpose is to Structure 1 of the K invention The present invention is an automatic system in which a calculation means selects a gear to be used according to vehicle speed, accelerator opening, etc., and an actuator meshes the selected gear to obtain a predetermined gear ratio. The transmission is characterized by being provided with a means for fixing the gear ratio of the transmission to the first gear, and fixing the gear ratio to the first gear until a predetermined vehicle speed is reached when starting the vehicle while loosening the braking by the braking means. This relates to an automatic transmission that generates sufficient torque even when starting on an uphill slope. Embodiment The present invention will be described below with reference to an illustrated embodiment. FIG. 1 shows an engine for an automobile 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 connected to the engine 10 via a timer 12.
Moreover, the timing of fuel injection is adjusted by this timer 12. Furthermore, the fuel injection pump 11 is equipped with a mechanical governor 13, and this governor 13 allows fuel injection
Af? It is designed to adjust j. On the back side of engine 10 is a flywheel. Zinc 14 established

A flywheel fixed to the end of the crankshaft is accommodated in the housing 14. A clutch (not shown) is installed on the back side of this flywheel.
Furthermore, a transmission 15 is attached to the rear side of the flywheel housing 14 so as to be connected to this clutch. The transmission 15 is configured to change the rotational speed of the engine 10 to an appropriate value and transmit it to the driving 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, respectively. Furthermore, a clutch actuator 19 for controlling connection and disconnection of a clutch attached to the rear side of the flywheel is connected to the transmission 15.
installed on the outer surface of the casing. Furthermore, a fuel control actuator 20 is provided on the front end side 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 each driven based on instructions from the microcomputer 21 via driving means. The input side of the microcomputer 21 is connected to a control box 22 . This control box 22 is equipped with a gear shift lever 23. 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 micro combi coater 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, and detects the vehicle speed based on the rotational speed of the output side of the transmission 15. Further, the engine rotation sensor 27 is attached to the front side of the engine 10 and detects the rotation speed of the engine 10. Also, the rack sensor 28 is attached to the tip side of the actuator 20. , to detect the position of the control rack of the fuel injection pump 11.Furthermore, the clutch sensor 29 is attached to the tip side of the clutch actuator 19, and is designed to detect the connection and disconnection state of the clutch. Furthermore, the input side of the microcomputer 21 constituting the calculation means of the automatic transmission according to this embodiment is connected to a service brake sensor 30.The service brake sensor 30 is composed of a pressure switch. The pressure inside the brake cylinder 31 is used to detect whether or not the service brake is activated.Furthermore, the input side of the microcomputer 21 is connected to a parking brake switch 32 which detects whether or not the parking brake is activated. Next, we will explain the operation of this automatic transmission with the above configuration.This operation is performed based on a program preset in the microcomputer 2.1. box 22
When the shift lever 23 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 17.
This is done via 18. To give an overview of the operation of automatic gear change, the micro combicoater 21 detects whether the gear 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 amount of depression or accelerator opening and vehicle speed are read from accelerator sensor 25 and vehicle speed sensor 26, respectively. Furthermore, the microcomputer 21 reads the map stored in its memory, and based on this map,
Performs calculations to determine 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 performed by the microcomputer 21.
Based on the command, the shift actuator 17 and the selection actuator 18 are activated via a drive means (not shown).
is operated to select a gear of the transmission 15, thereby achieving meshing of the selected gear of the transmission 15. 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 at the same time synchronizes with the end of the shift operation, the clutch is brought into the connected state again. 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 rolling backwards. When starting the vehicle while loosening the brake, the gear ratio of the transmission 15 is fixed at 1st speed. This state of being fixed to 1st gear continues until the vehicle speed reaches the maximum traction force point at the 1st gear ratio.
After this, the car automatically shifts to the drive range and resumes normal driving. 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. It's crowded. Then, it is determined whether the vehicle is in the drive range based on the output of the control box 22, and if the vehicle is in the drive range, the parking brake switch 32 is used to determine 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. The accelerator sensor 2 detects that the accelerator pedal 24 is depressed while the parking brake is activated.
5, or the pressure switch 30 detects that the service brake is in operation, and the depression of the accelerator pedal 24 is detected by the accelerator sensor 2.
5, the microcomputer 21 determines that the vehicle is about to start on an uphill slope, switches the gear ratio of the transmission 15 to 1st speed, and fixes it in this 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] * 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 upshift operation is performed. As described above, according to the automatic transmission according to the present embodiment, when the accelerator pedal 24 is depressed while the service brake or parking brake is released to start the vehicle, the transmission 15 is fixed at the first speed. Therefore, it is possible to transmit sufficient torque to the drive wheels, and even when starting on a steep slope, it is possible to prevent the vehicle from rolling backwards, making it possible to start smoothly and to provide an extra layer of safety. This makes it possible to provide superior automatic transmissions to customers. Moreover, since the system automatically shifts to the drive range when the vehicle speed reaches a certain value, the function of the automatic transmission is not impaired. [Effects of the Invention] Below-1-J: Sea urchin The present invention provides a means for fixing the gear ratio of the transmission at 1st speed, and when starting while loosening the braking by the braking means, the gear ratio is maintained until a predetermined vehicle speed is reached. is fixed at 1st speed. Therefore, according to the present invention, when starting on a slope, sufficient torque can be transmitted to the drive wheels, preventing the vehicle from rolling backwards, and making it possible to start smoothly.

[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 70-chat showing the starting operation of this automatic transmission. In the symbols used in the drawings, 15... Transmission 17... Shift actuator 18... Select actuator 19... Clutch actuator 21... Micro combi coater 25... Accelerator sensor 26... Vehicle speed sensor 30...service brake sensor 32...parking brake switch.

Claims (1)

[Claims] 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, the gear ratio of the transmission is determined. An automatic transmission characterized in that a means for fixing the gear ratio to the first gear is provided, and the gear ratio is fixed to the first gear until a predetermined vehicle speed is reached when starting the vehicle while loosening the braking by the braking means.