JPS6237549A - Automatic transmission - Google Patents

Abstract

PURPOSE:To make an optimum shift motion corresponding to a road grade performable, by detecting the road grade from a variation in car speed at the time of torque shutoff for the alteration of a gear position, and altering a shift point on the basis of the detected result. CONSTITUTION:When a shift signal is emitted, a car speed just before torque shutoff is read out at a microcomputer, and afterward a clutch actuator is operated at once, then clutch disengagement is carried out. Next, acceleration of a car is calculated from a count value of time in the microcomputer and a variation in the car speed after that, and a road grade is determined on the basis of the calculated result. Compensation counting corresponding to a road grade is registered in a register, and gear shifting at a later time is carried out with the shift point compensated by the compensation counting.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an automatic transmission, and more particularly to an automatic transmission that calculates an appropriate gear position and automatically changes the gear position using an actuator so that the gear position is the value obtained by this calculation. Regarding transmission. Summary of the Invention The present invention detects the gradient of a road surface based on a change in vehicle speed when an automatic transmission cuts off torque prior to changing its gear position, and detects the gradient of a road surface based on a change in vehicle speed. The shift point is changed, and the shift is always performed at the optimum shift point depending on the slope of the road surface. K Conventional Technique #IN Automatic transmissions have been proposed in order to omit the complicated operation of operating levers for changing transmission speeds. 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.

[Problems to be solved by the invention]

In conventional automatic transmissions like this,
The microcomputer changes gears in accordance with the vehicle speed while referring to a shift map that has been written in advance in the storage means of the microcomputer. The same speed change map was always used regardless of road conditions. Therefore, according to such a conventional transmission,
There has been a problem in that it is not possible to perform an optimum gear shift depending on the condition of the road surface on which the vehicle is traveling, for example, the slope of the road surface. This is mainly because it is impossible to detect the slope of the road surface, so it is not possible to change the shift point depending on the slope. The present invention has been made in view of these problems, and an object of the present invention is to provide an automatic transmission that shifts the shift point to an optimal position according to the slope of the road surface to perform gear changes. It is.

[Means to solve the problem]

The present invention provides a transmission that calculates a proper gear position and automatically changes the gear position using an actuator so that the gear position is the value obtained by this calculation, as shown in FIG. The present invention includes means for detecting the slope of the road surface based on a change in vehicle speed when torque is cut off for changing the gear position, and means for changing the shift point in accordance with the slope of the road surface. Therefore, according to the present invention, it is possible to know the gradient of the road surface from the change in vehicle speed when the torque is cut off due to the disengagement of the clutch prior to changing the gear position, and also to determine the shift point according to the gradient of the road surface. This makes it possible to shift at the optimal shift point.

【Example】

The present invention will be explained below with reference to an illustrated embodiment. FIG. 2 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 the 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 the governor 13 is adapted to adjust the amount of fuel to be 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 3o. This transmission 15 has an engine 1
Shift the rotation speed from 0 to an appropriate value, and rotate the propeller shaft 16.
The signal is transmitted to the drive wheels via the 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 micro combi coater 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 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 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 distal end side of the clutch actuator 19 to detect the connected and disconnected states of the clutch 30. 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 Acrocomputer 21, and when the shift lever 23 of the control box 22 is in the automatic 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 17.1.
8. To give an overview of the operation of automatic gear shifting, the microcomputer 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 accelerator opening degree and vehicle speed are read from the accelerator sensor 25 and vehicle speed sensor 26, respectively. Further, the microcomputer 21 reads the map stored in the memo IJ, 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 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 the gears of the transmission 15, thereby achieving meshing of the selected gears of the transmission 15.
It has become. Therefore, a predetermined gear ratio can be obtained in this way. Note that during this shift operation, the -temp clutch 30 is switched to the disconnected state by one actuator, and the clutch 3o is brought into the connected state again in synchronization with the end of the shift operation. Further, in the automatic transmission according to the present embodiment, the shift point is shifted depending on the road surface condition. To explain this operation based on the flowchart shown in Fig. 3, the microcomputer 21 judges whether there is a shift signal or not, and if there is a shift signal, it does not suddenly disengage the clutch. The vehicle speed V immediately before torque cutoff is determined by the vehicle speed sensor 26. Load. Immediately thereafter, the microcomputer 21 causes the clutch actuator 19 to disengage the clutch. Zarani microcomputer 21 is
Measurement of time t is started at the same time as the vehicle speed VO is read. This time is measured by counting clock pulses in the microcomputer 21.Then, the vehicle speed after a relatively short time t has elapsed after the torque is cut off is read.Generally, the clutch 30 is disconnected while the vehicle is running. When this happens, the torque applied to the drive wheels suddenly becomes O, causing the vehicle speed to change as shown in Figure 4.In other words, when driving on a flat road, the vehicle speed gradually decreases due to the resistance of the road surface.・On the other hand, in the case of an uphill road, the vehicle speed decreases rapidly as shown by the dotted line in Figure 4.In addition, in the case of a downhill road, the engine brake is released, so the vehicle speed decreases rapidly as shown by the dotted line in the same figure. The vehicle speed increases as shown by. This change in vehicle speed is given by the equation of motion shown by the following equation: V = V , 1 αt In this equation, α is the acceleration that acts on the vehicle body due to the slope of the road surface. From this equation, the microcomputer 21 divides the acceleration and calculates the gradient of the road surface based on this acceleration calculation.Then, the correction coefficient based on this tightening result is registered in the register.Then, the subsequent gear changes are performed. is performed at a shift point corrected by this correction coefficient. In other words, this correction coefficient is used to change the downshift or upshift timing. Therefore, by this operation, the optimum shift point is always maintained. A downshift or upshift is performed at the time of the shift, and it becomes possible to perform an automatic gear shift that is optimal depending on the road surface condition. Without being limited by the example, various modifications can be made based on the technical idea of the present invention.For example, in the above embodiment, the correction t1 number is registered in the register according to the calculation of the road surface slope, and The shift point is shifted according to this correction coefficient, but instead of this configuration, the memory of the microcomputer 21 is prestored with shift maps corresponding to various gradients, and the shift point is shifted according to the road surface. The map to be referenced may be selectively overridden depending on the slope.Effects of the Invention As described above, the present invention can detect the slope of the road surface from the change in vehicle speed when the torque is cut off to change the gear position. According to the present invention, an automatic transmission that can always shift gears at the optimum timing according to the slope of the road surface is provided. will be able to provide

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, FIG. 2 is a block diagram showing an automatic transmission according to an embodiment of the present invention, and FIG. 3 is a slope of the road surface for changing the shift point of this automatic transmission. FIG. 4 is a flowchart showing the operation for detecting the road surface slope. FIG. 4 is a graph showing the operation for detecting the slope of the road surface. In the symbols used in the drawings, 15... Transmission 17... Shift actuator 18... One select actuator... Clutch actuator 21... Microcomputer 25... Accelerator sensor 26... Vehicle speed sensor 30... is a clutch.

Claims (1)

[Claims] In a transmission that calculates an appropriate gear position and automatically changes the gear position using an actuator to the value obtained by this calculation, the torque for changing the gear position is An automatic transmission characterized in that it is provided with means for detecting the gradient of a road surface from a change in vehicle speed when the vehicle is shut off, and means for changing a shift point in accordance with the gradient of the road surface.