JPS59159627A - Surge protecting circuit in contact type detecting terminal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surge protection circuit for a contact portion in a control device having a contact type detection end.

Conventionally commonly used sensors for each pole have a mechanical contact, and when this contact comes into contact with an object, the electric potential 'kM' is detected, and based on the signal obtained, Devices that operate the entire control system are common. The above-mentioned contact element is based on a simple connection/disconnection of a contact material (it is not limited to a switch), but also includes an encoder or a potentiometer in which a slider slides on a wiring pattern.

As an example of the above-mentioned conventional device, there is an example of a control circuit for a variable damping force type hydraulic shock absorber for automobiles, etc., and an example of an encoder for detecting the (b) rotation angle position of the motor for adjusting the damping force, which is adopted in this device. We will congratulate you using Figures 1 to 4.

In FIG. 1, reference numeral 1 indicates a changeover switch (in this conventional example, each damping force setting position is divided into three categories: high, medium, and low) for selecting one of the desired damping force setting positions (in this conventional example, each damping force setting position is divided into three categories: high, medium, and low). 2 is a selection reference signal generation circuit that receives one selection signal selected by the selection switch 1 and generates a selection reference signal in accordance with the selection signal; By comparing the selection reference signal outputted from the selection reference signal generation circuit 2 and the output number corresponding to the rotation angle position of the motor 4, which will be described later,
A signal comparison circuit 5 for determining mismatch or coincidence between the selection reference signal and the output signal is a motor drive circuit that operates upon receiving the mismatch or coincidence signals outputted from the signal comparison circuit 3. 4 is a motor that is driven or stopped by the motor drive circuit 5; 6 is a motor that is driven or stopped by the motor drive circuit 5; 6 is the rotation angle of the drive shaft 4a of the motor 4; This is a rotational angle position detection circuit that inputs an output signal corresponding to the position. In addition, when this rotation angle position detection circuit 6 is composed of a predetermined encoder, a signal for converting the contact signal output from this detection (b) path 6 into a digital signal and inputting it to the signal comparison circuit 3 is used. The entire conversion circuit 7 is provided between the rotation angle position detection circuit 6 and the signal comparison circuit 3.

T is a hydraulic shock absorber having a structure in which the motor 4 rotates an adjuster that also serves as a damping car, and its details are described in the second section.
As shown in Fig. 3. In other words, in Figure 2, 9 is made! 11 is filled with a cylinder with one end sealed, and lO is a piston rod extending through the cylinder 9 with the other end sealed. 11 is a piston that is slidably pushed into the cylinder 9, and this piston 11 causes the cylinder 9 to
The interior is divided into two parts, an upper liquid chamber 12 and a lower liquid chamber 13.

This piston 11 has the upper and lower valley fluid chambers 12°1.
A damping force generating means 14 is provided that generates a flow resistance in the number of actuated displacements between the two.

Reference numeral 15 denotes a generally cylindrical stud that connects the piston rod 10 and the piston 11, and the circular part of this stud 15 has a V@crab housing part 16 and a sales adjustment part '6.
An axial through hole 1 that communicates with the inside of the portion 16 and the lower liquid chamber 13.
7 are formed respectively. Further, the cylindrical wall portion 1 of the stud 15
5a, as shown in FIG. 3, which is a sectional view taken along the line ■-■ in FIG. There are four orifices 18, 19, 20 arranged at intervals.

In the adjuster accommodating portion 16 of the stud 15, a w@Toyoko 8 which is rotationally driven by a motor 4 housed in the hollow portion of the piston rod 10 is rotatably housed. An axial through hole n that opens and communicates with the lower Q chamber 13, and this through hole n and the stud 1.
A delay hole which can selectively communicate with any one of the orifices 18, 19 and 20 provided in the opening 5 is formed respectively. The input end of the motor 4 described in ll1j is connected to a motor drive circuit 5 as shown in FIG. It has become.

According to the configuration of the control circuit S and the hydraulic shock absorber T as described above, the vertical movement of the piston rod 1° accompanying the piston 11 causes the through oil passage 5, which constitutes the damping force generating means 14 provided in the piston 11, to 25, one of the upper and lower liquid chambers 12, while receiving resistance from the spring force of 26. By displacing and flowing the working fluid between 13 and 13, it is possible to secure the desired clamping force at 1.

On the other hand, if an arbitrary damping force setting position is selected depending on the driving condition of the vehicle, for example, the intermediate reduction force setting position f as shown in FIG. A selection reference signal corresponding to the selection signal is output from the selection reference signal generation circuit 2. This selection reference signal is connected to a signal comparison circuit 3, and in addition to the selection reference signal, this comparison circuit 3 also receives the current value of the drive shaft 4a provided in the motor 4 from the rotation angle position detection enclosure 6. Since the rotational position detection signal indicating the rotational angular position is converted into a digital value by the signal conversion circuit 7 and input, these two S numbers are compared in this signal comparison circuit. This signal ratio soft circuit 3 outputs a match signal when the two signals match, and a mismatch signal when they do not match. Therefore, the motor drive circuit 5 is operated by these signals. In other words, when the coincidence signal is input to the motor drive circuit 5, this motor drive circuit 5
The supply of drive force to the motor 4 is stopped, and therefore the rotation of the motor 4 is stopped. On the other hand, if a mismatch signal is input to the motor drive circuit 5, the drive current is transferred from the motor drive circuit 5 to the motor 4 in response to this mismatch signal.
Therefore, the motor 4 continues to rotate until the output signal from the signal comparison circuit 3 becomes a matching signal. In this way, the adjuster 8 is inserted into the orifice 19 provided in the stud 15 for medium damping force setting selected by the changeover switch
The communication hole n will be in open communication. For this reason, the upper and lower liquid chambers 12. , 13 is bypass-passed through the orifice 19, thereby adjusting the damping force obtained by the damping force generating means 14 to ensure the full desired damping force. be able to.

A specific example of the rotational chromaticity position detection circuit 6 forming a part of the control circuit B having the above configuration will be described with reference to FIG. That is, the figure shows an example of a conductive pattern that constitutes the entire structure of a normal encoder, in which a first conductive pattern 31 is placed on an insulating substrate.
, the second conductive pattern 32 and the common conductive pattern 32 are formed concentrically, and a contact holder extends from the center point 0 so as to cover each of the above patterns, and the center point 01 is the center of rotation. Due to the rotational driving force of the motor 4, the contact piece rotates while slidingly contacting each of the patterns 31, 32, and 33. A is an electrode of the first conductive pattern 31, B is an electrode of the second conductive pattern 32, and C is an electrode of the common conductive pattern 33. Now, the rotation area of the contactor (ra p b
Let's consider dividing it into four areas, ec and d. And when the contact element is in contact with the 1st or 24m pattern,
1", electrodes A and B when non-contact is "o"
The signals obtained are shown in Table 1.

As can be seen from Table 1, when the contacts A are in the same area, the same signal is always sent to the electrode A, regardless of the slight difference in their angular positions.

The rotational angle position of the motor 4 indicated by θσ is divided into four inertia areas, converted to a digital value by the signal conversion circuit 7, and then input to the signal comparison circuit 3.

In the above configuration, the power source for driving loads such as motors is usually dedicated to the battery or generator installed in the vehicle, but this is likely to occur while the vehicle is running (and is adversely affected by high voltage surges unique to vehicles). However, this high voltage surge mainly causes contact failures in the encoder etc. In the above example, the first conductive pattern 31, the second conductive pattern 32 and the common 4T pattern or these conductive patterns 31, 32 ,3
The contact portions of the contacts 3 that come into contact with each other are susceptible to breakdown due to the surge current, leading to poor contact and resulting in operational problems. In order to protect all contacts from such high voltage surges, conventional methods have generally been used to absorb surges by inserting filter paths using capacitors, coils, resistors, etc. If such a circuit element is inserted, the operation time will be delayed due to the influence of the inherent time constant, and the time loss during switching will cause the operation of the entire device to slow down.

An object of the present invention is to provide a device that can prevent the contact degradation in the conventional contact type detection terminal as described above, and can significantly increase the response speed of the control system without delaying the operating time. In order to achieve this purpose, the fpJ shoulder contact type detection terminal is configured to be separated from the power supply line and the ground line, and a first Zener diode is connected between the power supply line connected to the detection terminal and the ground. A second Zener diode having approximately the same standard value as the first Zener diode is placed between the output line connected from the detection terminal to the control signal output terminal side and the ground. The main focus of this invention is to provide a surge protection circuit for a contact type detection end, which is characterized by the following features:

Embodiments of the present invention will be explained below with reference to the drawings.

That is, in FIG. 5, 41 conceptually indicates a contact type detection terminal, and in this example, a switch piece 42 and a protective resistor 43
(R1 and the metal fittings are facing down. The protective resistor 43 is connected to the switch piece 4.
2, or a fixed resistance inserted from the outside, and has the function of protecting the contact material from overcurrent when the switch is turned on.

Reference numeral 44 indicates a control system, and the detection terminal 41 senses the signal from the signal output terminal 45, and the ``fc11L energy signal full energy signal full output is the battery isoelectricity w147 is the bleeder resistance. It is configured to be disconnected from the power supply line E and the ground line/G by lines XX' and 2-in Y-Y'. 481t first
A Zener diode z1 is connected in the opposite direction between the one source line connected to the detection end 41 and the ground.

49 is a second Zener diode z2, and the output line 0 connected from the detection terminal 41 to the signal output terminal 45 side
and ground in the opposite direction. M+Jk The first Zener diode 48 and the second Zener diode 49 must be made of components having substantially the same standard im'ii. Note that (capital) is a resistor for signal output.

To briefly explain the operation of the surge protection circuit according to the present invention, first, when a surge having a busis voltage is applied between the X-X' line or the Y-Y' line and the ground, the first Zener Due to the surge absorption effect of the diode 48 and the second Zener diode 49, the potentials at both ends X' and Y' of the detection end 41 become the same potential. That is, if it is assumed that the Zener voltages of the first and second Zener diodes 48 and 49 are equal, even if the switch piece 42 of the detection terminal 41 is disconnected, the surge current will not flow through the switch piece. The contact portion of No. 42 does not cause a failure situation based on the t-sect.

However, the first and second Zener diodes 4
It is practically impossible to use equal components, and it is impossible for the Zener voltages of both Zener diodes to have a slight difference. The Zener voltage of the Zener diode 48 of the younger brother 1 is Vz5, the voltage of the second Zener diode 490 is vz, and vzl>v
In the case of z2, considering all aspects, the surge current S obtained by will flow to the detection end 41. Conversely, if we consider the case where vzl<vz2, it is surprising that the surge current does not flow to the detection terminal 41 at all, but entirely flows to the first Zener diode 48 side.

Next, considering the case where a surge with a negative voltage is applied between the X-X' line or the Y-Y' line and the ground, this negative voltage surge is applied to the first and second Zener diodes 48 and 49, respectively. against Jl
The current flows in the direction of the lIi force and flows to the ground, and no surge current flows to the detection end 41.

From the above results, the magnitude relationship between the Zener voltage vz of the first and second Zener diodes 48 and 4.9 and vz,6 is as follows: vzl>vz, or VZt<VZzteh
Only in this case, a surge current of 1 will flow through the detection end 41 rather than the surge current of 1 obtained by the formula. Therefore, the maximum allowable current p of the detection end 41 is p>I
1, even if the surge current 8 is repeatedly applied to the detection end 41, there is no risk of current destruction noise occurring at the contact portion.

The maximum permissible current Hp of the detection terminal 41 can be determined by the specific resistance value determined by the selection of the contact material or by the inserted fixed resistance Rs.

As explained in detail above, according to the present invention, the current caused by the harness between the contact type detection end and the control system is basically applied to the droplet portion that constitutes the entire detection end. Since it can be set so that even if a primary surge current is applied, it will be smaller than the maximum allowable current Ip of the detection terminal, there is an advantage that contact failure will hardly occur. The life of the detection end is extended,
Improved reliability. jl! Since contact protection circuit components such as capacitors and coils are not attached to the conventional circuit, there is no delay in operating time due to the time constants of these components.
l? Since it is possible to speed up the response speed of the lI control system,
In particular, in the case of the reduced pressure relaxation device shown in the embodiment, any desired relaxation characteristics can be quickly obtained and the running performance of the vehicle can be improved. In addition, since the main components of the surge protection circuit are two Zener diodes of the same standard, the circuit configuration is easy and the cost can be reduced. It is highly effective when applied to the surge protection circuit of equipment that connects the terminal and control system with a harness.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional control circuit for a variable damping force type hydraulic shock absorber, Fig. 2 is a sectional view of main parts showing the configuration of the hydraulic shock absorber, and Fig. 3 is a line ■-m in Fig. 2. A cross-sectional view along
FIG. 4 is a plan view of a conductive pattern showing an example of a conventional rotation angle position detection device, and FIG. 5 is a circuit diagram showing an example of a surge protection circuit in a contact type detection end according to the present invention. 41...Detection end, 42...Switch piece, 43...
Protective resistor, shrine...control system, 45...signal output terminal,
46...Power supply, 47...Bleeder resistance, 48...
・First Zener diode, 49... Second Zener diode, Blade... Resistor for signal output.

Claims (1)

[Claims] (1) Has a contact type detection end with a specific resistance value,
In a control device that operates a control system based on an electrical signal sensed by the detection end, a curved contact type detection end is cut out from a power supply line and a ground line, and four connections are made to the detection end. A first Zener diode is disposed between the power supply line and the ground, and the first Zener diode is connected between the output line connected from the detection end to the control signal output terminal side and the ground. A surge protection circuit at a contact type detection end characterized by the provision of a second Zener diode with a full tolerance value.