JPH03250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electromagnetic clutch provided between a vehicle engine and a transmission.

Some vehicle clutches use magnetic particle type electromagnetic clutches to automate gear shifting operations and clutch operations using a clutch pedal when starting a vehicle.In this type of device, when gear shifting operations are performed, the electromagnetic clutch is activated by a gear shift signal from the shift lever. The excitation current is cut off to disconnect the engine and transmission, and the electromagnetic clutch is connected when the gear shift operation is completed. Furthermore, this electromagnetic clutch is de-energized when the accelerator pedal is released, but when the accelerator is depressed, the excitation current is controlled in accordance with the engine speed, allowing the vehicle to start smoothly. Furthermore, if the vehicle speed exceeds the set value (e.g. 20km/h),
By fully energizing the clutch regardless of the accelerator pedal position or engine speed, it is possible to apply engine braking even when the accelerator pedal is released when the vehicle is decelerating, and it also prevents clutch slippage even during normal driving. Prevention is being done to eliminate transmission loss and reduce heat generation in the clutch.

By the way, with this configuration, if a gear shift operation is performed while the vehicle speed is running at a predetermined value or higher (which can be said to be almost normal running), the excitation current of the electromagnetic clutch after the shift is completed will rapidly increase directly toward full excitation. Because of this, the electromagnetic clutch suddenly fully engages, causing a large shift shock and causing discomfort to the driver.

This invention has been made in order to deal with the above-mentioned situation, and it reduces the shift shock by adding a shift shock prevention circuit that slowly increases the excitation of the electromagnetic clutch after the shift operation is completed to buffer and connect the clutch. By blocking the function of the shift shock prevention circuit when the vehicle speed is below a set value, for example, when starting in both directions, the vehicle starts with the predetermined vehicle start characteristics without being affected by the clutch torque set by the shift shock prevention circuit. This makes it possible to launch the An embodiment of the present invention shown in the drawings will be described below.

That is, in the figure, 1 is the excitation coil of the magnetic particle type electromagnetic clutch installed between the engine and transmission of the car, and the voltage of the car battery (V _BAT ) is
is applied. 2 is an output transistor that is connected in series to the power supply circuit of this excitation coil 1 and performs switching operation, and 3 and 4 are output transistors of this output transistor.
A diode and a resistor constitute a commutation circuit that releases the electromagnetic energy of the excitation coil 1 with a predetermined time constant when it is OFF, and the coupling torque of the electromagnetic clutch is approximately proportional to the current value of the excitation coil 1. Occur.

On the other hand, 5 is an ignition coil provided to ignite the engine, and this current is connected to an interrupter 6 which opens in synchronization with the ignition timing of the engine.
Interrupted by 7 is a differentiation circuit that differentiates the switching output of the interrupter 6 and generates a trigger signal with a frequency proportional to the engine speed; 8 is a monostable circuit that generates a fixed time pulse in synchronization with the trigger signal of this differentiation circuit. The duty factor of this output pulse becomes proportional to the rotational speed due to fluctuations in the rotational period. 9 is an accelerator switch that is linked to an accelerator pedal (not shown) and turns on when the pedal is depressed; 10 is an accelerator switch that turns on when the vehicle speed exceeds a set value (for example, 20 km/h)
A vehicle speed switch 11 is a speed change switch that is provided on a shift lever of a transmission (not shown) and is turned on when the gear is changed.
11 are connected in series with resistors 12, 13, and 14, respectively, and are applied with an output voltage (V _CC ) of a constant voltage circuit (not shown) that constants the battery voltage.
An HL level output is generated at the connection point with this resistor depending on the ON/OFF status of each switch. 15 is the monostable circuit 8 when the accelerator switch 9 is turned on.
16 is an AND gate that allows the output of
An OR gate that OR-synthesizes the output of the AND gate and the output of the vehicle speed switch 10, 17 is an oscillator that generates a pulse output of a predetermined duty factor at a constant frequency, and this output pulse drives the output transistor 2 on and off. The pulse duty factor is set so that the current value of the excitation coil 1 is approximately 1/2 of the total excitation current value. 18 is a switching circuit that switches between the output of the OR gate 16 and the output of the oscillator 17;
AND gates 181, 182, inverter 183,
It consists of an OR gate 184. Reference numeral 19 indicates the OR gate 1 when the gear is changed by the output of the gear change switch 11 given through the inverter 20.
This is an AND gate that prevents the output transistor 2 from being driven by the output of 84. Reference numeral 21 denotes a switching control circuit that provides a switching signal to the switching circuit 18, and is connected in series with low resistors 211 and 212 that generate a reference voltage (V _T ) obtained by dividing the constant voltage (V _CC ). A resistor 213 and a capacitor 214 that receive voltage (V _CC ), and this capacitor voltage (V _C )
and the reference voltage (V _T ) and generates a switching signal whose level is inverted depending on the magnitude relationship between the two, and the capacitor 2 which receives the output of the speed change switch 11 via a resistor 216.
14 includes a transistor 217 that controls charging and discharging. Reference numeral 22 denotes an AND gate that prevents the speed change signal from passing through the switching control circuit 21 when the vehicle speed is below a predetermined set speed.

Next, the operation of the device configured in this way will be explained. As the engine rotates, the monostable circuit 8 is triggered by the output of the ignition interrupter 6 via the differentiating circuit 7 to generate a constant time pulse with a frequency proportional to the engine speed, and the duty factor of this output pulse rotates. It is proportional to the number.
Now, when starting the car, when the shift lever is operated to the first gear position of the transmission, this operation turns the gear change switch 11 ON, which turns it ON.
The AND gate 19 is closed by the H level signal via the inverter 20, the output transistor 2 is turned off, and the excitation coil 1 of the electromagnetic clutch is in a non-excited state, so that the rotation of the engine is not transmitted to the transmission. When the speed change operation is completed and the speed change switch 11 is turned off, the AND gate 19 is placed in a state that allows the input signal to pass through. Next, when the accelerator pedal is depressed, accelerator switch 9 is turned on.
The AND gate 15 passes the output of the monostable circuit 8 and connects it to the selection circuit 18 via the OR gate 16.
is input. At this time, the switching control circuit 21 normally sets the voltage (V _C ) of the capacitor 214 to the reference voltage (V _T ).
Since it is in a larger state, the switching signal is at L level, and the switching circuit 18 outputs the output of the OR gate 16.
The signal is applied to the output transistor 2 via the AND gate 19, and the output transistor 2 is controlled by switching in accordance with the output pulse of the monostable circuit 8. Here, when the engine speed increases in response to the depression of the accelerator pedal, the closing rate of the transistor 2 increases in proportion to the increase, so the excitation current coupling torque of the electromagnetic clutch 1 increases in proportion to the rise in the rotation speed. The car starts smoothly.

When the vehicle speed exceeds a predetermined speed (for example, 20 km/h), the vehicle speed switch 10 turns ON and generates an H-level signal. level output is generated, output transistor 2 is turned on continuously, and excitation coil 1 of the electromagnetic clutch is turned on.
is fully excited. This makes it possible to apply engine braking even when the accelerator pedal is released when the car is decelerating, and also prevents the electromagnetic clutch from slipping even during normal driving, eliminating transmission loss and reducing heat generated by the electromagnetic clutch. .

The ON (H level) signal of the vehicle speed switch 10 opens the gate of the AND gate 22, allowing the output of the speed change switch 11 to pass through. On the other hand, when changing gears while the car is running, the AND gate 19 is closed by the signal from the gear shift switch 11 by operating the shift lever, turning off the transistor 2 and cutting off the excitation of the electromagnetic clutch. The gear shift operation is performed with the clutch in the open state. By the way, in a gear shifting operation when the vehicle speed is higher than the set value (20 km/h), the ON (H level) signal of the gear shift switch 11 turns on the transistor 217 of the switching control circuit 21 and discharges the charge of the capacitor 214.
4 becomes smaller than the reference voltage (V _{T )} , the output of the operational amplifier 215 becomes H level, and the switching circuit 18 selects the output pulse of the oscillator 17.
The output pulse of the oscillator 17 is selected based on the predetermined time (T _O ) required for the capacitor 214 to be charged to the reference voltage (V _T ) with a time constant determined by the resistor 213 after the transistor 217 is turned off after the speed change operation is completed. This lasts only after the gear shifting operation is completed.
When the gate of the AND gate 19 is opened, the signal driving the transistor 2 becomes an output pulse determined by the oscillator 17 for an initial predetermined time (T _O ), and is determined by the duty factor of this output pulse. The current in the excitation coil 1 increases along the time constant of the circuit toward the excitation current value (approximately 1/2 of the total excitation current), and after a predetermined time (T _O ) has elapsed,
When switched to full excitation by the switching circuit 18, the current increases toward full excitation. Therefore, the electromagnetic clutch is not directly energized to full excitation, but the excitation is slowly increased by two-step excitation with a certain time limit, so that the electromagnetic clutch is buffered and connected, and the shock applied to the vehicle body during gear shifting can be reduced.

As mentioned above, the AND gate 22 prevents the output of the shift switch 11 from passing through when the vehicle speed is below a set value, and stops the operation of the switching control circuit 21. Therefore, for example, when the vehicle starts moving, the AND gate 22 prevents the output of the shift switch 11 from passing through. Even if the switch 11 is activated, the output transistor 2 is completely prevented from being driven by the output of the oscillator 17, and the electromagnetic clutch torque is inadvertently generated by the output of the oscillator 17, which is completely unrelated to the driver's driving intention. The vehicle can be started stably without being controlled by the electromagnetic clutch torque corresponding to the output of the monostable circuit 8 which is proportional to the rotation speed.

In the above embodiment, if the predetermined time (T _O ) during which the oscillator 17 is selected after the shift is completed in order to prevent shift shock is controlled in accordance with the shift position of the transmission, shift shock can be prevented in accordance with the shift position. effect can be obtained. Furthermore, in the above embodiment, the set vehicle speed for fully energizing the electromagnetic clutch and the set vehicle speed for blocking the shift shock prevention function are set at the same level, but they do not necessarily have to be at the same level and there may be a difference between the two. It can also produce almost the same effects.

As described above, according to the present invention, the electromagnetic clutch disposed between the engine and the transmission of a vehicle is controlled in response to the gear shifting operation and the accelerator operation, and the clutch operation during gear shifting is automated, and the vehicle speed is Based on the output of the detection means, the electromagnetic clutch is fully energized when the vehicle speed exceeds a set speed, regardless of whether the accelerator is released, to enable engine braking during vehicle deceleration, and furthermore, the excitation current of the clutch is fully energized after the gear shift operation is completed. By providing a gear shift shock preventing means for suppressing a sudden rise in speed and making a buffer connection, the shift shock can be reduced, and by blocking the function of the gear shift shock preventing means when the vehicle speed is below a set value, For example, when the vehicle is started, the clutch is not energized by the clutch torque set by the shift shock prevention circuit, and it is possible to stably start the vehicle by predetermined starting clutch torque control.

[Brief explanation of the drawing]

The figure is an electrical configuration diagram showing an embodiment of the present invention. In the figure, 1 is an excitation coil, 2 is an output transistor,
5 is an ignition coil, 7 is a differential circuit, 8 is a monostable circuit, 9 is an accelerator switch, 10 is a vehicle speed switch, 11 is a transmission switch, 17 is an oscillator, 18 is a switching circuit, 21 is a switching control circuit, 22 is an AND gate It is.

Claims (1)

[Claims] 1. An electromagnetic clutch disposed between the engine and the transmission of the vehicle, a speed change operation detection means that de-energizes the electromagnetic clutch when the shift lever of the transmission is operated, and a gear change operation detection means that de-energizes the electromagnetic clutch when the accelerator pedal is released. an accelerator switch that shuts off the clutch and allows its excitation when depressed; a vehicle speed detection means that fully energizes the electromagnetic clutch regardless of the operation of the accelerator switch when the vehicle speed exceeds a set vehicle speed; and a vehicle speed detection means that receives the output of the shift operation detection means. A shift shock prevention circuit for suppressing the rising speed of the electromagnetic clutch torque after the end of the shift lever operation and buffering and connecting the electromagnetic clutch, and means for blocking the function of the shift shock prevention circuit when the vehicle speed is lower than a set vehicle speed. An electromagnetic clutch control device for vehicles consisting of: