JPH01203721A - Method and device of controlling starting of electromagnetic clutch - Google Patents

Abstract

PURPOSE:To decrease the generation of peak torque of an electromagnetic clutch, to improve reliability, and to reduce weight, by providing an oscillating circuit to output a pulse signal by means of a starting signal for an electromagnetic clutch, and a logic circuit to output a signal according to signals from the oscillating circuit and a timer. CONSTITUTION:When a starting signal for an electromagnetic clutch 3 is generated, an oscillating circuit 21 outputs an ON and an OFF pulse signal. A timer 22 outputs an OFF signal for a given time starting from the generation of the starting signal for the electromagnetic clutch 3, and outputs an ON-signal after lapse of a given time. An OR circuit 23 outputs a signal of a logic sum of signals outputted from the oscillating circuit 21 and a timer 22, the signal is amplified by a power transistor 27 to feed it to the electromagnetic clutch 3. This constitution reduces the generation of peak torque of the electromagnetic clutch, and enables improvement of reliability and reduction of weight.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for controlling the activation of an electromagnetic clutch that connects an engine and a load driven by the engine, such as a bus air conditioner or any other arbitrary device. , and its activation control device.

``Conventional technology'' In conventional sub-engine type bus air conditioners, the blower fan is connected to the sub-engine for cooling under the control of an electromagnetic clutch, and is charged by a generator driven by the vehicle's main or sub-engine when blowing air. A power clutch is provided to switch the drive system of the blower fan so that the blower fan is driven by a double-shaft motor powered by a storage battery. If you start the sub-engine with the electromagnetic clutch engaged, the torque fluctuations caused by the engine's first explosion may break the shaft of the blower fan or damage the leaf spring or rubber hub of the electromagnetic clutch, so start the engine with the electromagnetic clutch disconnected. A computer-controlled system was configured to engage the electromagnetic clutch when the engine rotates as low as, for example, 720 rpm. but,
This system also has a problem in that the peak torque is large when the electromagnetic clutch is engaged, and the same problems as above occur when used for a long period of time. However, if the engine speed is further reduced, the engine will stop when the electromagnetic clutch is engaged. In addition, if reliability is improved by making the shaft of the blower fan fitted to the electromagnetic clutch thicker, there is a problem in that the electromagnetic clutch becomes larger and weighs more.

``Problems to be Solved by the Inventionj'' The present invention has been made to solve the above-mentioned problems, and is an electromagnetic clutch that aims to reduce the peak torque when engaging the electromagnetic clutch, improve reliability, and reduce weight. An object of the present invention is to provide a clutch activation control method and device.

"Means and effects for solving the problem" A start control method of the present invention in accordance with the above object is a start control method of an electromagnetic clutch that connects a rotating engine and a load driven by the engine, in which a start signal of the electromagnetic clutch is The electromagnetic clutch is operated intermittently until the rotational speed of the load rises to a required minute difference between the rotational speed of the engine and the rotational speed of the load, and the rotational speed of the load and the engine are maintained at the desired rotational speed. It is characterized in that the electromagnetic clutch is brought into a connected state when the rotational speed difference is within a slight difference.

According to the startup control method of the present invention, the load is gradually accelerated while the electromagnetic clutch is engaged and engaged, and the electromagnetic clutch is engaged after the load rotation speed reaches a state where there is almost no difference from the engine rotation speed. Therefore, the peak torque of the electromagnetic clutch is significantly reduced.

The start control device of the present invention includes an oscillation circuit that outputs an on/off pulse signal when a start signal for an electromagnetic clutch is generated, and an oscillation circuit that outputs an on/off pulse signal when a start signal for an electromagnetic clutch is generated. A timer that outputs an off signal for a predetermined time until the rotation speed reaches a required minute difference in rotation speed, and generates an on signal after the predetermined time, and when both the oscillation circuit and the timer signals are off. comprises a logic circuit that outputs an off signal and outputs an on signal when either of the two signals is on, and a power transistor that amplifies the output signal of the logic circuit; The present invention is characterized in that the clutch is operated on and off, and after the predetermined time period, the electromagnetic clutch is brought into a connected state.

When the start control device of the present invention having the above configuration is used, when a start signal for the electromagnetic clutch is generated, a pulse signal is generated from the oscillation circuit and applied to the power transistor via the logic circuit, so that the pulse signal is applied to the power transistor. The signal is amplified by the transistor and supplied to the electromagnetic clutch. As a result, the electromagnetic clutch operates intermittently for a predetermined period of time, the load is gradually accelerated, and when the load reaches a rotational speed that is almost the same as the engine rotational speed, the timer on signal is amplified by the transistor and the electromagnetic clutch is activated. By applying the force to the clutch, the electromagnetic clutch is brought into a connected state.

In the above startup control device, if a Zener diode is connected between the collector and emitter of the transistor,
The surge voltage when the electromagnetic clutch is disengaged is bypassed by the Zener diode, the transistor is protected from the surge voltage, and the electromagnetic clutch disengages better than when a reverse polarity diode is connected in parallel with the electromagnetic clutch.

Another start-up control device of the present invention includes an energizing means that can turn on and off the energization of the electromagnetic clutch, an oscillator that turns on and off the electromagnetic clutch via the energizing means, and a first rotational speed sensor that detects the rotational speed of the engine. and a second rotation speed sensor that detects the rotation speed of the load, and a differential amplifier that generates an output signal when the difference between the two rotation speeds reaches a required minute difference in rotation speed. The present invention is characterized in that the electromagnetic clutch is brought into a connected state via the energizing means when the difference is within a required minute rotational speed difference. According to this configuration, the electromagnetic clutch is operated intermittently at first, the load is gradually accelerated, and when it is detected that there is actually almost no difference between the rotational speed of the load and the engine rotational speed, the electromagnetic clutch is engaged. be put into a state.

"Embodiment" Next, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

In FIG. 1, an oscillation circuit 21 outputs an on/off pulse signal as shown in FIG. 2, and is connected to a power source B via a switch 24 or a relay in the illustrated path. The timer 22 outputs an off signal for a predetermined time A after the switch 24 is turned on, and outputs an on signal after a predetermined time A. The OR circuit 23 outputs a signal that is the logical sum of the signals output from the oscillation circuit 21 and the timer 22, and
6 to the base-emitter path of the power transistor 27. A Zener diode 2 is connected between the collector and emitter of the power transistor 27.
8 are connected. An electromagnetic clutch 3 is connected in series with the collector/emitter of the power transistor 27, and the electromagnetic clutch 3 is further connected to the power source B via a switch 24.
It is connected to the. The electromagnetic clutch 3 is attached to a double-shaft motor 4 as shown in FIG.

The role of the Zener diode 28 is to
Its purpose is to absorb surge voltage during FF operation. That is, when the clutch 3 is OFF, a surge voltage of several hundred V is generated across the clutch 3, and the Zener diode 2
8, this surge voltage would be applied between the collector and emitter of the transistor 27, damaging the transistor 27, but by using a Zener diode with a Zener voltage lower than the withstand voltage of the transistor 27, the transistor The current bypassing 27 protects transistor 27.

Further, as another method of absorbing the surge voltage, there is a structure in which a diode 29 is provided in parallel with the electromagnetic clutch 3 as in another embodiment shown in FIG. 5, but the circuit shown in FIG. If this happens, the electromagnetic clutch 3 will become difficult to disengage, so it is better to use the circuit shown in FIG.

In FIG. 4, the rotational speed of the sub-engine 1 is controlled to be almost constant when the electromagnetic clutch 3 is started, and the rotational speed of the proa fan 6 and the rotational speed of the engine 1 are controlled by the intermittent operation of the electromagnetic clutch 3. A predetermined time A at which the rotational difference becomes a minute rotational difference is measured at the time of trial production and set in the timer 22 in advance. In addition, in FIG. 4, the compressor 2 can be connected to the sub-engine 1 via another electromagnetic clutch as described later. 5 is a universal shaft, 7
is a V-belt, 8 is a capacitor fan, 9 is a capacitor
The radiator 10 is a cooler case. 12 is an outer wall as described later.

"Operation" In the above configuration, when the start signal of the electromagnetic clutch 3 enters the oscillation circuit 21 by turning on the switch 24,
The oscillation circuit 21 outputs a pulse signal that turns on and off at intervals as shown in FIG. timer 2
2, even if the switch 24 is turned on, A is turned off for a predetermined period of time.
In order to generate a signal, the OR circuit 23 judges two signals from the oscillation circuit 21 and the timer 22, and turns off both signals.
By outputting an OFF signal when either signal is ON, and outputting an ON signal when either signal is ON, a pulse signal similar to that shown in FIG. 2 is generated on the output side of the OR circuit 23. O
The pulse signal generated from the R circuit 23 is amplified by the power transistor 27 and supplied to the electromagnetic clutch 3. As a result, the electromagnetic clutch 3 operates intermittently (chopping) for a predetermined time A, and the blower fan 6 is gradually accelerated by the rotating engine 1 shown in FIG. The number of rotations is almost the same as the rotation speed of the engine 1, for example, there is a minute difference in the rotation speed of about 100 rpm, and at the same time, the timer 22 generates a continuous ON signal, so the OR
This ON signal is applied to the base of the transistor 27 via the circuit 23, and the electromagnetic clutch 3 is continuously energized by the conduction of the transistor 27, and the blower fan 6 is connected to the engine 1. For this reason, as shown in Fig. 3(a), in the past, a large transient peak torque occurred during connection, but in this embodiment, a chopping operation is performed as shown in Fig. 3(b). The peak torque at the time is significantly reduced.

"Other Embodiments" If the above embodiment is adopted in a dry electromagnetic clutch, an intermittent "click, click" sound will be generated during chopping operation. This can be reduced by adding powdered MNlt material to the contact surface.

Another embodiment for reducing intermittent noise is shown in FIG.
FIG. 6 is a cross-sectional view showing the details of part B in FIG. 4, showing the structure of the electromagnetic clutch 3 that connects and disconnects the sub-engine 1 and the compressor 2. 101, a rotor 102 that rotates together with the rotating shaft 2a of the compressor 2, and a joint 103 that has a clutch plate 103a and is connected to the engine flywheel 11.
This electromagnetic clutch 3 is sealed by a housing 100 and is sound-insulated so that intermittent noise does not leak outside.

In addition, as another example for reducing intermittent noise,
As shown in FIG. 4, the entire air conditioner may be sealed by the outer wall 12 of the sub-engine type bus air conditioner.

Furthermore, depending on the transmission torque of the device using the electromagnetic clutch, the engine speed, etc., the O
By selecting the FF time and ON time as well as the chopping operation time, the reliability of the electromagnetic clutch as a whole can be improved without reducing the life of the clutch plate. For example, the reliability of the electromagnetic clutch as a whole can be improved. When it is large, the ON time is shortened compared to the OFF time in the chopping operation, and the chopping operation time is lengthened.

"Effects" As described above, the startup control method of the present invention operates the electromagnetic clutch intermittently when the electromagnetic clutch is engaged,
Since the electromagnetic clutch is brought into engagement when the load is gradually accelerated to a predetermined minute difference between the engine rotational speed and the engine rotational speed, the peak torque of the electromagnetic clutch during an engagement transition is significantly reduced. This reduction in peak torque improves the reliability of the electromagnetic clutch,
Alternatively, the diameter of the electromagnetic clutch shaft hole can be reduced, and the electromagnetic clutch can be made smaller and lighter.

Furthermore, the activation control device of the present invention is constituted by an oscillation circuit, a timer, and a logic circuit, and can implement the method of the present invention with a simple structure. However, the start control method of the present invention mainly includes a rotation speed sensor that detects the rotation speed of the engine and the load, and a differential amplifier that determines that there is actually a slight difference between the two rotation speeds. It may be implemented by a start control device, and can be widely applied even when the engine model and load type are different.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a startup control device implementing the method of the present invention, FIG. 2 is a waveform diagram showing pulses generated by the oscillation circuit in this embodiment, and FIGS. 3(a) and (b) ) is a characteristic diagram showing how the peak torque decreases due to intermittent operation (chopping operation) of the electromagnetic clutch, Fig. 4 is a plan view showing the bus air conditioner in this embodiment, and Fig. 5 is a diagram showing another embodiment. FIG. 6 is a sectional view showing still another embodiment. 110. Sub-engine, 2.1. compressor, 2
a, compressor rotating shaft, 3, magnetic clutch, 4101 double-shaft motor, 610. Prowafan, 900. Condenser radiator, 12°1.
Outer wall, 21, oscillation circuit, 22, timer,
23. OR circuit, 24, switch, 27. ,,
power transistor, 28. , Zener diode 29 , Diode 100 , Housing 101 , Stator 102. ,,rotor, 103,,,joint, 103a,,,clutch plate. Figure 1 10B Figure 4 Figure 5 Figure 18 Figure 6

Claims (4)

[Claims] (1) In a method for starting control of an electromagnetic clutch that connects a rotating engine and a load driven by the engine,
The electromagnetic clutch is operated intermittently until the rotational speed of the load increases to a required minute difference between the rotational speed of the engine and the rotational speed of the load. 1. A method for controlling start-up of an electromagnetic clutch, characterized in that the electromagnetic clutch is brought into a connected state when the rotational speed of the electromagnetic clutch becomes within a required minute rotational speed difference. (2) In a start control device for an electromagnetic clutch that connects a rotating engine and a load driven by the engine,
An oscillation circuit that outputs an on/off pulse signal when an electromagnetic clutch start signal is generated, and an oscillation circuit that outputs an on/off pulse signal when the electromagnetic clutch start signal is generated, and the load rotation speed and the engine rotation speed are adjusted to the required minute rotation speed. An off signal is output for a predetermined time until the difference is reached, and after the predetermined time, an off signal is output when both the timer that generates the on signal, the oscillation circuit, and the timer are off, and the off signal is output. It includes a logic circuit that outputs an on signal when either of the two signals is on, and a power transistor that amplifies the output signal of the logic circuit, and the transistor operates the electromagnetic clutch intermittently for the predetermined period of time. An electromagnetic clutch activation control device characterized in that the electromagnetic clutch is brought into a connected state after a certain period of time. (3) The electromagnetic clutch activation control device according to claim 2, characterized in that a Zener diode is connected between the collector and emitter of the transistor. (4) In a start control device for an electromagnetic clutch that connects a rotating engine and a load driven by the engine,
energizing means capable of turning on and off energization of the electromagnetic clutch;
An oscillator that turns on and off the electromagnetic clutch via this energizing means, a first rotation speed sensor that detects the engine rotation speed, and a second rotation speed sensor that detects the load rotation speed, and a difference between the two rotation speeds. and a differential amplifier that generates an output signal when a required minute rotation speed difference is reached, and connects the electromagnetic clutch via the energizing means when the rotation speed difference between the two sensors becomes within the required minute rotation speed difference. A starting control device for an electromagnetic clutch, characterized by: