JPH01141261A - Automatic transmission - Google Patents

Abstract

PURPOSE:To prevent shift-up operation even upon slippage of drive wheel by employing such constitution where speed change operation is prohibited when an output from a vehicle speed sensor at the output side of a transmission is shifted more than a predetermined amount from an actual vehicle speed. CONSTITUTION:A microcomputer 21 judges whether an output from a vehicle speed sensor 26 interlocked with a transmission 15 exceeded 1.5times of an actual vehicle speed obtained through calculation, If the answer is YES, shift operation of the transmission 15 is prohibited while the answer is NO, speed change is performed through normal shifting operation. Consequently, even when a vehicle is started on a snow road and the like having low friction coefficient to cause slippage of a drive wheel 36, shift-up operation of the transmission is prohibited resulting in improvement of operational feeling.

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION 1 The present invention relates to an automatic transmission, and in particular calculates an appropriate gear position and automatically changes the gear position using an actuator to reach the gear position obtained by this calculation. The present invention relates to an automatic transmission, and further relates to an automatic transmission suitable for use in an automatic transmission in which a mechanical clutch and a gear transmission are controlled by a microcomputer to perform an automatic gear change operation. [Summary of the Invention] The present invention provides a method for changing the speed of an automatic transmission when the output value of a vehicle speed sensor moving on the output side of the transmission deviates by a predetermined amount or more with respect to the actual vehicle speed obtained from the rotation speed of a driven wheel, for example. This is to prevent the automatic transmission from shifting up if the drive wheels spin when starting on a snowy road with a low coefficient of friction. This is what I did. ``Prior Art'' Automatic transmissions have been proposed in order to omit the driver's frequent gear shifting operations.This automatic transmission uses a calculation means such as a microcomputer that responds to vehicle speed, accelerator opening, etc. In addition to selecting the gears to be used, the actuator meshes the selected gears to automatically obtain a predetermined gear ratio.By equipping a car with such an automatic transmission, the driver's There is almost no need to operate a lever for gear shifting.Prior art related to the present invention includes, for example, Japanese Patent Application Laid-open No. 127559/1982.
There is no description regarding the gist of the present invention.

Problem to be solved by the invention When the shift up line or down shift line is exceeded, a gear change operation is performed via the actuator. The vehicle speed is obtained from the rotation speed on the output side of the transmission. Therefore, when the vehicle starts on a road with a low coefficient of friction, such as a snowy road, the drive wheels slip and spin. This slipping causes the vehicle speed sensor to detect the vehicle speed, resulting in an unnecessary upshift operation, which prevents a smooth start. The present invention has been made in view of these problems, and is designed to prevent upshifting even if the drive wheels slip when starting on a road with a low coefficient of friction such as a snowy road. The purpose is to provide an automatic transmission with improved performance. Means for Solving Problem K] As shown in FIG. 1, the present invention calculates an appropriate gear position, and automatically adjusts the gear position using an actuator to achieve the value obtained by this calculation. In the transmission adapted to be changed, a vehicle speed sensor that moves with the output side of the transmission, and means for determining the actual vehicle speed from the number of rotations of the driven wheels are provided, and the output of the vehicle speed sensor is provided with respect to the actual vehicle speed by the means. The gear shift operation is prohibited when the value deviates by a predetermined amount or more. [1] According to the present invention, when the driving wheels slip due to a starting operation on a road with a low coefficient of friction such as a snowy road, the output of the vehicle speed sensor deviates by more than a predetermined amount from the actual vehicle speed. As a result, the gear shifting operation is prohibited. K Embodiment The present invention will be described below with reference to an illustrated embodiment. FIG. 2 shows an automobile engine equipped with an automatic transmission according to an embodiment of the present invention, and this diesel engine 10 is equipped with a fuel injection pump 11,
This pump 11 sequentially supplies fuel to each cylinder of the engine 10. fuel injection pump 1
1 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 includes a governor 13, which moves a control rack (not shown) to adjust the amount of fuel injected. The flywheel housing 1 is located on the back side of the engine 10.
4 is provided, and a flywheel fixed to the end of the crankshaft is accommodated within this housing 14. A clutch 30 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 the clutch 30. This transmission 15 has an engine 1
The rotation speed of 0 is changed to a predetermined value, and the propeller shaft 16
, is transmitted to the drive wheels 36 via the differential gear 37 and the axle shaft. 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 for controlling connection and disconnection of a clutch 30 attached to the back side of the flywheel is connected to the transmission 1.
It is attached on the outer surface of the casing of No. 5. 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 4
The three 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 degree of opening 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, a clutch sensor 29, and a gear position sensor 31, respectively. The vehicle speed sensor 26 is provided on the side surface 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 is configured to detect the rotation speed of the engine 10. Moreover, the rack sensor 28 is attached to the tip side of the actuator 20, and the rack sensor 28 is attached to the tip side of the actuator 20.
The position of the control rack No. 1 is detected. Further, the clutch sensor 29 is attached to the tip side of the clutch actuator 19, and the clutch sensor 29
The state of connection and disconnection of 0 is detected. Further, the gear position sensor 31 is provided on the upper part of the transmission 15, and is adapted to detect the gear position. Further, a rotation detection sensor 34 is connected to the microcomputer 21 as shown in FIG. The rotation detection sensor 34 is provided on the side surface of a driven wheel, ie, a front wheel 35, for example, and is configured to detect the rotation speed of the front wheel 35. Therefore, the microcomputer 21 controls the rotation detection sensor 3.
4, the actual vehicle speed is detected from the rotation of the front wheels 35. 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, and when the shift lever 23 of the control box 22 is in the automatic shift position, the shift operation is automatically performed. ing. On the other hand, when the gear shift lever 23 is in the manual position, the manually selected gear shift operation is performed by the actuator 17.
．． This is done via 18. To give an overview of the automatic gear shifting operation, the microcomputer 21 detects whether the gear shift lever 23 of the control box 22 is in the automatic gear shifting position.
In the case of the automatic shift position, the maximum depression or opening of the accelerator pedal 24 and the vehicle speed are read from the accelerator sensor 25 and the vehicle speed sensor 26, respectively, at regular intervals. Further, the microcomputer 21 reads a 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,
Do not perform gear shifting operation. 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. Note that during this shift operation, the -H clutch 30 is switched to the disconnected state by the actuator 19, and the clutch 30 is brought into the connected state again in synchronization with the end of the shift operation. The transmission 15, whose gear position is automatically changed in this manner, prohibits an upshift operation when the drive wheels 36 slip. As shown in FIG. 4, the microcomputer 21 reads the number of revolutions of the front wheels 35 using the rotation detection sensor 34, and calculates the actual vehicle speed from the read value of the number of revolutions. Furthermore, the microcomputer 21 uses a vehicle speed sensor 26 provided on the side of the transmission 15 to
The rotation speed on the output side of the transmission 15 or the rotation speed of the propeller shaft 16 is read. The microcomputer 21 then determines whether the output of the vehicle speed sensor 26 exceeds 1.5 times the actual vehicle speed obtained by the above calculation. If the rear wheels 36 are slipping, the vehicle speed sensor 26
In this case, the shift operation of the transmission 15 is prohibited because the output of the vehicle is more than 1.5 times the actual vehicle speed. On the other hand, if the output of the vehicle speed sensor 26 is within 1.5 times the actual vehicle speed, the transmission 15 is shifted by a normal shift operation. In this way, the automatic transmission 15 according to this embodiment
According to the above, a rotation detection sensor 34 is added to one of the left and right front wheels 35, and its output is input to a control computer 21 to monitor the actual vehicle speed. When the vehicle speed obtained by the vehicle speed sensor 26 becomes 1.5 times or more the actual vehicle speed, it is determined that the drive wheels 36 are idling, and the transmission 15 is activated by the actuators 17 and 18.
Upshifting is prohibited. Therefore, even if the drive wheels 36 slip and spin after starting on a road with a low coefficient of friction such as a snowy road, the upshift operation of the transmission 15 is prohibited, improving the driving feeling. . Effects of the Invention 1 As described above, the present invention is provided with a vehicle speed sensor linked to the output side of the transmission and a means for determining the actual vehicle speed from the rotation of the driven wheels, and the output value of the vehicle speed sensor is determined based on the actual vehicle speed. The gear shift operation is prohibited if the shift is more than a predetermined amount. Therefore, if the drive wheels slip when starting on a road with a low coefficient of friction, such as a snowy road, the transmission will be prohibited from upshifting, preventing careless gear shifting and improving the driving feel. It becomes possible to improve. 4. Brief description of the drawings - Fig. 1 is a block diagram showing the gist of the present invention, Fig. 2 is a block diagram showing an in-house transmission according to an embodiment of the present invention, and Fig. 3 is a vehicle equipped with this automatic transmission. FIG. 4 is a flowchart showing an operation for prohibiting a gear shift operation when the driving wheels slip. In addition, in the symbols used in the drawings, 15... Transmission 17... Shift actuator 18... Select actuator 21... Microcomputer 26... Vehicle speed sensor 34, Speed/rotation detection sensor 35... It's the front wheel.

Claims (1)

[Claims] In a transmission that calculates an appropriate gear position and automatically changes the gear position by an actuator to the value obtained by this calculation, a vehicle speed sensor that is linked to the output side of the transmission is provided. and means for determining the actual vehicle speed from the rotational speed of the driven wheels, and the gear shifting operation is prohibited when the output value of the vehicle speed sensor deviates by a predetermined amount or more from the actual vehicle speed determined by the means. Features an automatic transmission.