JPH07190232A - Noise absorption circuit - Google Patents

Abstract

PURPOSE:To provide a noise absorption circuit furnished doubly with responsibility and an excessive voltage resistance property at low cost. CONSTITUTION:A serial circuit of a baristor 2 and a diode 5 is connected in parallel with a solenoid coil l and the diode 5 is connected in the reverse direction against the voltage applying direction to the solenoid coil l. When transitors Tr1, Tr2 are off, an electric current flows on a course of baristor 2 diode 5-solenoid coil l, and when counter electromotive voltage generated on the solenoid coil 1 becomes lower than a restriction voltage value of the baristor 2, the electric current is cut off. Suppose transient voltage is generated at the time when the transistors Tr1, Tr2 are on. In this case, the transient voltage is dispersed and applied to the diode 5 and the baristor 2. As the diode 5 is high in a resistance value in its reverse direction and rich in a pressure proof property, too, voltage is never excessively applied to the baristor 2, and even if it is a small capacity, the baristor 2 is never broken.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise absorption circuit suitable for use in a finger control transmission system.

[0002]

2. Description of the Related Art In automobiles, particularly large-sized bus lines, starting and stopping are frequently performed, and gear shifting operations are repeated a considerable number of times during driving. This shift operation is performed by a change lever on the driver's seat, and a long rod is connected to the change lever from the change lever at a distance of about 10 m from the rear portion of the vehicle body, and the shift stage of the transmission is switched via this rod. Therefore, both the operating force and the stroke of the change lever are large, which causes the driver's fatigue.

Therefore, in recent years, instead of connecting the change lever and the transmission with a rod, the change lever unit and the control box are connected by electric wiring, and the change lever unit is connected to the control box in accordance with the operation of the change lever. A finger control in which a position signal is not sent, a shift control signal (shift control signal) is generated in the control box, and the generated shift control signal is sent to the gear shift unit, so that the gear position of the transmission is switched. -A transmission system (hereinafter referred to as FCT) is adopted.

In this FCT, a shift control signal is generated based on the change lever position signal from the change lever unit, and the generated shift control signal is sent from the control box to the gear shift unit. Then, by this shift control signal, the select cylinder in the gear shift unit and the solenoid valve attached to the shift cylinder are selectively driven, the supply state of compressed air from the air tank is switched, and the piston position in the cylinder is switched. As a result, the shift fork of the selective actuation unit moves, and the shift speed of the transmission is switched. If this FCT is used, the gear shifting operation is replaced with a mechanical remote control mechanism by an electric pneumatic control mechanism, and the operating force and shift stroke can be greatly reduced and driving fatigue can be reduced.

[0005]

DISCLOSURE OF THE INVENTION The conventional FCT described above
Since noise is generated when the current supplied to the solenoid coil of the solenoid valve is cut off, a varistor is connected in parallel with the solenoid coil in order to absorb this noise. That is, as shown in the circuit configuration of the main part in FIG. 12, the varistor 2 is connected in parallel to the solenoid coil 1 as a voltage limiting element.

According to this noise absorbing circuit, if the drive circuit 3 turns on the transistors Tr1 and Tr2 in response to an input signal, the transistor Tr1 → the solenoid coil 1
→ Current from the vehicle-mounted battery 4 flows through the path of the transistor Tr2, and the solenoid valve is driven. When the drive circuit 3 turns off the transistors Tr1 and Tr2, a counter electromotive voltage is generated in the solenoid coil 1, a current flows in the path of the varistor 2 → the solenoid coil 1, and the counter electromotive voltage generated in the solenoid coil 1 is It is limited to the limit voltage value of and then gradually becomes smaller. When the counter electromotive voltage generated in the solenoid coil 1 becomes less than the limit voltage value of the varistor 2, the varistor 2
→ The current flowing in the path of the solenoid coil 1 suddenly decreases and the solenoid valve is turned off. That is, the varistor 2
By using, the noise generated by the solenoid coil 1 is absorbed and the transistors Tr1 and Tr are
The electromagnetic valve is turned off at a relatively early time point after the turning off of 2 to ensure quick response.

However, in this noise absorption circuit,
It has a good responsiveness, but has the drawback of being weak against external excessive voltage. For example, when the in-vehicle battery 4 is charged from the alternator and a large load is removed,
The voltage at the terminals may rise sharply and the overvoltage condition may continue for some time. Such an excessive voltage causes the transistor Tr
If it occurs when 1 and Tr2 are turned on, the varistor 2 is destroyed. A large-capacity varistor 2 may be used, but the varistor 2 is not available as a commercial product at present and is a custom-made product, which increases the cost. In addition, its outer shape is large and requires a large installation space.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a noise absorbing circuit having both responsiveness and withstand voltage resistance at low cost. .

[0009]

In order to achieve such an object, a first invention (the invention according to claim 1) of the invention is to serially connect a diode and a voltage limiting element in parallel with a solenoid coil of an electromagnetic valve. In the circuit, the diode is connected in the direction opposite to the direction of voltage application to the solenoid coil. The second invention (the invention according to claim 2) is
A circuit in which a first diode, a voltage limiting element, and a second diode are connected in series in parallel to the first to Nth solenoid coils, and the first and second diodes are connected in the direction of voltage application to the solenoid coil. On the other hand, they are connected in the opposite direction and commonly for the voltage limiting element.

[0010]

Therefore, according to the first aspect of the invention, the current flows through the path of the voltage limiting element (diode) → the diode (voltage limiting element) → the solenoid coil, and the noise generated in the solenoid coil is absorbed. According to the second invention, the first diode → the voltage limiting element (common) → the second diode
Current from the diode → solenoid coil path,
Noise generated in the first to Nth solenoid coils is absorbed.

[0011]

EXAMPLES The present invention will now be described in detail based on examples. FIG. 3 is a system configuration diagram showing an embodiment of an FCT (finger control transmission system) to which the present invention is applied. In the figure, 10 is a change lever unit (hereinafter referred to as CLU), 11
Is a control box (hereinafter referred to as ECU), 12
Is a gear shift unit (hereinafter, referred to as GSU), 13 is a transmission, 14 is an engine, 15 is an air tank, 16 is an emergency switch box (hereinafter,
EMS), 17 is a clutch pedal, S1 is a first clutch switch for detecting the start of depression of the clutch pedal 17, S2 is a second clutch switch for detecting completion of depression of the clutch pedal 17, and 18 is a three-way solenoid valve. , 19 is a reducing valve for pressure reduction, and 20 is a display unit.

As shown in FIG. 4, the CLU 10 operates the change lever 10-1 to operate the forward 5 speeds (“1”, “2”, “3”, “4”,
"5"), reverse 1st step ("R"), neutral ("N")
1), "N2", "N3"), and a change lever position signal G corresponding to each position. That is, if the change lever 10-1 is in the "N1" position, the sensors SiB and Se provided in the CLU 10 are attached.
When A is turned on, a change lever position signal G indicating the position “N1” is sent to the ECU 11. Then, when the change lever 10-1 is moved from the position "N1" to the positions "N2" and "N3" in the select direction, the sensors SeB and SeC are turned on and the position "N2",
The change lever position signal G indicating “N3” is transmitted to the ECU 11
Sent to. If the change lever 10-1 is moved from the position "N3" in the shift direction to the position "5", the sensor SiC is turned on. Therefore, the change lever position signal G indicating the position "5" is sent to the ECU 11
Sent to. FIG. 5 shows a correspondence relationship between each position of the change lever 10-1 and the operating states (on states) of the sensors SiA to SiC and SeA to SeC.

The ECU 11 controls the rotation state N of the engine 14.
Based on the change lever position signal G from the CLU 10, the engine rotation state Ne and the vehicle speed V are input.
The shift control signal S is generated in consideration of the above information, and the generated shift control signal S is sent to the GSU 12. In addition, EC
In U11, the change lever position signal G indicates the position "N".
If the signals are "1", "N2", and "N3" (neutral signals), a drive signal is sent to the three-way solenoid valve 18, and compressed air from the air tank 15 is sent to the CLU 10. With the compressed air passing through the three-way solenoid valve 18, the CLU 10
At, the reaction force with respect to the change lever 10-1 is generated.

Upon receiving the shift control signal S from the ECU 11, the GSU 12 switches the gear stage of the transmission 13. FIG. 6 is a diagram showing a configuration of a main part of the GSU 12. In the figure, 4-1 is a shift cylinder, 4-2 is a select cylinder, and 4-3 is a selection operating unit. Solenoid valves MVA and MVB are attached to the shift cylinder 4-1.
Electromagnetic valves MVC and MVD are attached to the select cylinder 4-2. The shift control signal S from the ECU 11 is given to the solenoid valves MVA to MVD. The shift control signal S selectively drives the solenoid valves MVA to MVD to switch the supply status of the compressed air from the air tank 15 and shift cylinder 4-1 and select cylinder 4-.
The positions of the pistons 4-12 and 4-22 in 2 are switched, the shift fork (not shown) in the selection actuating unit 4-3 moves, and the shift speed of the transmission 13 is switched. FIG. 5 shows the correspondence relationship between each position of the change lever 10-1 and the driving state (ON state) of the solenoid valves MVA to MVD.

The shift cylinder 4-1 and the select cylinder 4-2 have sensors SiA 'to SiC' and SeA 'to Se for detecting the positions of their pistons 4-12 and 4-22.
C'is arranged. This sensor SiA '~ Si
The detection status of the piston positions C ′, SeA ′ to SeC ′ is given to the ECU 11 as a gear position detection signal GP.
The ECU 11 compares the gear position detection signal GP with the change lever position signal G, and if the position shifted by the change lever 10-1 and the actually switched gear position match, the ECU 11 sends the signal to the three-way solenoid valve 18. A drive stop signal (shift completion feedback signal) is sent to shut off the supply of compressed air from the air tank 15 to the CLU 10. As a result, the reaction force to the change lever 10-1 disappears, and it is possible to feel that the shift operation to the desired position is completed. The gear position detection signal GP from the GSU 12 is also given to the display unit 20. As a result, the current gear position is displayed on the display unit 20.

The EMS 16 includes a CLU 10, an ECU 11,
Change lever 10- due to abnormality in electrical signal system such as wiring
This is an emergency gear shift control device that allows the GSU 12 to be directly driven to switch the gear stage of the transmission 13 when gear shifting is not possible even if 1 is operated. This EMS1
6 is provided with rotary switches 16-1 and 16-2 as shown in the front view of FIG. The rotary switch 16-1 is for forward movement, the rotary switch 16-2 is for backward movement, and is normally in the OFF position.

When the rotary switch 16-1 is rotated one step clockwise from the OFF position, the EMS 16 causes the ECU
The control stop signal E for preventing the transmission of the shift control signal S from 11 is transmitted, and the shift control signal S ′ according to an arbitrary neutral position is generated. The shift control signal S ′ is supplied to the GSU 12 instead of the shift control signal S. When the rotary switch 16-1 is further rotated clockwise by one stage, the shift control signal S ′ corresponding to the position “N2” is generated, and when it is rotated by another stage, the shift control signal S corresponding to the position “2” is generated. 'Is generated. The shift control signal S ′ from the EMS 16 causes the GS
The solenoid valves MVA to MVD in U12 are selectively driven, and the gear position of the transmission 13 is set to the forward second speed position. As a result, it is possible to take a second start without using the CLU 10. Rotary switch 16-
By operating 2, the rotary switch 16-1 can be moved backward without using the CLU 10 as in the case of the rotary switch 16-1.

[Embodiment 1] In the FCT constructed and operated as described above, the solenoid valves MVA to M in the GSU 12 are
A series circuit of a varistor and a diode is connected in parallel to the solenoid coil of a solenoid valve such as the VD or the three-way solenoid valve 18. That is, as shown in FIG. 1 which is a circuit configuration of a main part of the conventional circuit (FIG. 12), a series circuit of a varistor 2 and a diode 5 is connected in parallel with a solenoid coil 1 of a solenoid valve. Are connected in the direction opposite to the direction of voltage application to the solenoid coil 1.

According to this noise absorbing circuit, when the drive circuit 3 turns on the transistors Tr1 and Tr2 in response to the input signal, the transistor Tr1 → the solenoid coil 1
→ Current from the vehicle-mounted battery 4 flows through the path of the transistor Tr2, and the solenoid valve is driven. When the drive circuit 3 turns off the transistors Tr1 and Tr2, a counter electromotive voltage is generated in the solenoid coil 1, and a current flows in the path of the varistor 2 → diode 5 → solenoid coil 1, and the counter electromotive voltage generated in the solenoid coil 1 is , Is limited to the limit voltage value of the varistor 2, and then gradually decreases. Solenoid coil 1
When the counter electromotive voltage generated at 1 becomes equal to or lower than the limit voltage value of the varistor 2, the current flowing in the path of the varistor 2 → diode 5 → solenoid coil 1 decreases sharply and the solenoid valve is turned off. That is, by using the varistor 2,
The noise generated by the solenoid coil 1 is absorbed, and the solenoid valve is turned off at a relatively early time point after the transistors Tr1 and Tr2 are turned off, so that quick response is secured.

Here, assume that a large load is removed when the vehicle-mounted battery 4 is charged from the alternator. In this case, the voltage of the + terminal of the vehicle-mounted battery 4 may rise sharply and the transient voltage state may continue for a while. Now, such an excessive voltage causes the transistor Tr1,
It is assumed that this occurs when Tr2 is on. In this case, the transient voltage is distributed and applied to the diode 5 and the varistor 2 connected in series. Here, the diode 5 has a high resistance value in the opposite direction and has a high withstand voltage. Therefore, the voltage is not excessively applied to the varistor 2, and the varistor 2 is not destroyed even with a small capacity.

[Embodiment 2] In Embodiment 1, the path of noise absorption is in the order of varistor 2 → diode 5 → solenoid coil 1. However, as shown in FIG.
-> Varistor 2-> The path of solenoid coil 1 may be used. [Third Embodiment] The varistor 2 in the first and second embodiments is shown in FIG.
A Zener diode 6 may be used as shown in FIG.

[Embodiment 4] FIG. 2 is a circuit diagram of a main portion showing another embodiment of the noise absorbing circuit according to the present invention. In this embodiment, a circuit in which a first diode, a varistor, and a second diode are connected in series in this order to the solenoid coil of each solenoid valve is connected in parallel with the varistor being shared. That is, the solenoid coil 1-1
A circuit in which a diode 5-11, a varistor 2 ', and a diode 5-12 are serially connected in parallel in parallel with the diode 5-11 and 5-12 in the opposite direction to the voltage application direction to the solenoid coil 1-1. On the other hand, the varistor 2'is shared and the diode 5-n1, the varistor 2 ', and the diode 5 are connected in parallel to the solenoid coil 1-n.
-N2 are connected in series in the order of the diode 5-n
1 and 5-n2 are connected in a direction opposite to the direction of voltage application to the solenoid coil 1-n.

In the case of this embodiment, if the drive circuit 3'turns off the transistors Tr11 and Tr12, a current flows through the route of diode 5-11 → varistor 2 '→ diode 5-12 → solenoid coil 1-1, The counter electromotive voltage generated in the solenoid coil 1-1 is limited to the limiting voltage value of the varistor 2 ', and then gradually decreases. When the counter electromotive voltage generated in the solenoid coil 1-1 becomes less than the limit voltage value of the varistor 2 ', the diode 5-11 → the varistor 2' →
The current flowing in the path from the diode 5-12 to the solenoid coil 1-1 is rapidly reduced, and the solenoid valve is turned off.

Further, the drive circuit 3'is constituted by the transistor Trn.
1 and Trn2 are turned off, diode 5-n1 → varistor 2 '→ diode 5-n2 → solenoid coil 1
The counter electromotive voltage generated in the solenoid coil 1-n due to the current flowing through the -1n path is limited to the limit voltage value of the varistor 2 ', and then gradually decreases. When the counter electromotive voltage generated in the solenoid coil 1-n becomes equal to or lower than the limit voltage value of the varistor 2 ', the current flowing through the path of the diode 5-n1 → varistor 2' → diode 5-n2 → solenoid coil 1-n It decreases sharply and the solenoid valve is turned off.

That is, in this embodiment, the number of varistor provided for the solenoid coils 1-1 to 1-n is one, and the noise generated from the solenoid coils 1-1 to 1-n can be absorbed at low cost. it can. In this case, as in the case of the first embodiment, the diodes 5-11 and 5-12 to 5-5 are used.
It goes without saying that -n1,5-n2 ensures the withstand voltage resistance. In this embodiment, since it is considered that the solenoid coils 1-1 to 1-n are turned off at the same time, the varistor 2'has a larger capacity than the varistor 2 shown in the first embodiment. ing. [Fifth Embodiment] Although the varistor 2'is used as the voltage limiting element in the fourth embodiment, a Zener diode 6'may be used as shown in FIG.

[0026]

As is apparent from the above description,
According to the first aspect of the present invention, since the series circuit of the voltage limiting element and the varistor is connected in parallel to the solenoid coil of the solenoid valve, the diode is connected in the direction opposite to the direction of voltage application to the solenoid coil. The voltage limiting element ensures fast response and the diode ensures transient voltage resistance. Therefore, without using a large-capacity voltage limiting element, that is, at low cost, responsiveness and transient voltage resistance can be obtained. It becomes possible to have both. Further, according to the second aspect of the invention, a circuit in which the first diode, the voltage limiting element, and the second diode are connected in series in parallel to the first to Nth solenoid coils is provided in the first and second circuits. Since the diode is connected in the direction opposite to the direction in which the voltage is applied to the solenoid coil and the voltage limiting element is commonly used, in addition to the effect of the first aspect of the invention, noise generated from a large number of solenoid coils with a single varistor is provided. The effect that absorption can be performed at low cost is exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a noise absorption circuit according to the present invention (first
(Embodiment) FIG.

FIG. 2 is a circuit configuration diagram of a main part showing another embodiment (fourth embodiment) of the noise absorbing circuit.

[Fig. 3] FCT (Finger Control Transmission System) to which this noise absorption circuit is applied
It is a figure which shows one Example.

[Figure 4] CLU (change lever unit) in FCT
FIG. 6 is a diagram showing a shift pattern in FIG.

FIG. 5 is a diagram showing a correspondence relationship between a position of a change lever in a CLU and operating states of respective sensors and a corresponding relationship between operating states of respective solenoid valves in a GSU (gear shift unit).

FIG. 6 is a diagram showing a main part of a GSU in FCT.

FIG. 7 is a front view of an EMS (emergency switch box) in FCT.

FIG. 8 is a circuit configuration diagram of essential parts showing another embodiment (second embodiment) of the noise absorbing circuit according to the present invention.

FIG. 9 is a circuit configuration diagram of essential parts showing another embodiment (third embodiment) of the noise absorbing circuit.

FIG. 10 is a circuit configuration diagram of essential parts showing another embodiment (fourth embodiment) of the noise absorbing circuit.

FIG. 11 is a circuit configuration diagram of a main part showing another embodiment (fifth embodiment) of the noise absorbing circuit.

FIG. 12 is a circuit configuration diagram of a main part showing a conventional noise absorption circuit.

[Explanation of symbols]

 1 Solenoid coil 2 Varistor 3 Drive circuit 4 Vehicle battery 5 Diode Tr1, Tr2 Transistor 6 Zener diode

Claims (2)

[Claims] 1. A series circuit of a diode and a voltage limiting element is connected in parallel to a solenoid coil of an electromagnetic valve, the diode being connected in a direction opposite to a direction in which a voltage is applied to the solenoid coil. Noise absorption circuit. 2. A circuit in which a first diode, a voltage limiting element, and a second diode are connected in series in parallel to the first to Nth solenoid coils to connect the first and second diodes to the solenoid. A noise absorbing circuit, which is connected in a direction opposite to a direction in which a voltage is applied to the coil, and is also shared by the voltage limiting element.