JPH0236287Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a circuit protection device, in particular, it mounts circuit components on a circuit board to form a predetermined circuit, and also mounts the circuit board inside an outer case. This invention relates to a circuit protection device that is inserted into a circuit and sealed with resin.

〓Summary of the invention〓 The present invention provides a holder for holding circuit components arranged so as to face the outer surface of the resin enclosing the circuit board, supports the legs of this holder by the circuit board, and supports the circuit board. The circuit component is held on the holder in a state separated from the circuit board, and the circuit component facing the outer surface of the encapsulating resin can be reliably positioned.

<Prior Art> For example, in order to protect the control circuit of an engine generator, a protection device as shown in FIG. 6 has been conventionally used. That is, the control circuit is formed on a printed wiring board, this board is inserted into an exterior case 60, and this board is further sealed with resin 61. In this case, circuit components such as the variable resistor 62 for later adjustment need to be exposed on the outer surface of the resin 61, so as shown in FIG. It is installed in a floating state, and the lead leg 64 of the variable resistor 62
By inserting the tube 65 into the circuit board 63, the circuit board 63 is held apart from the tube 65.

Problems to be Solved by the Invention According to such a conventional structure for supporting the variable resistor 62, the elasticity of the tube 65 makes the length of the tube 65 unstable at the time of installation.
It is difficult to insert the tube 65 into the board 63 and attach it to the board 63. Further, since the component 62 freely moves left and right even after being attached to the board 63, it is necessary to adjust its position before injecting the resin 61, and the position of the component 62 is not stable even after the resin 61 is injected. Furthermore, there is a possibility that the legs 64 of the variable resistor 62 may be severed due to external force being applied while the printed wiring board 63 on which the circuit components are mounted is being transported.

The present invention has been developed in view of these problems, and is particularly designed to facilitate the installation of components that are held apart from the circuit board, and to ensure that their positions are determined. It is an object of the present invention to provide a circuit protection device that reliably prevents the legs of a motor from being severed.

〓Means for solving the problem〓 In this invention, circuit components are mounted on a circuit board to form a predetermined circuit, and the circuit board is inserted into an outer case and sealed with resin. In the apparatus, a holder for holding circuit components arranged to face the outer surface of the resin is provided, legs of the holder are supported by the circuit board, and the circuit components on the holder are held by the circuit board. It is designed to be held away from the

〓Effect〓 Therefore, according to the present invention, it is possible to securely hold circuit components that are placed facing the outer surface of the resin in a state away from the circuit board using the holder, thereby eliminating the above-mentioned drawbacks of the conventional method. becomes possible to eliminate.

〓Example〓 The present invention will be described below with reference to an illustrated example.
FIG. 5 shows a control circuit for an engine generator according to an embodiment of the present invention. In this circuit, the voltage generated by the exciter coil 3 is rectified by a full-wave rectifier 10 and smoothed by a capacitor 21 to become a DC voltage. This DC voltage is supplied to a field coil 2 connected in series with a control circuit 4 consisting of Darlington-connected transistors 7 and 8. The field current flowing through the field coil 2 generates an output voltage at the terminals U, V, and W of the output coil 1, but an intermediate tap is provided from the middle of the output coil to detect fluctuations in the output voltage. The voltage generated at these intermediate taps is output as a DC detection voltage from the detection circuit 6 having a full-wave rectifier 11, a resistor 20, and a capacitor 24.

This voltage is input to the second control circuit 5 that controls the control circuit 4, and the voltage at point A is determined by the resistance values of the three resistors 17, 18, and 19. Therefore, the fluctuation of the output voltage generated in the output coil 1 is caused by the resistor 1 connected in series.
Appears at both ends of 8 and 19. The voltage at point A divided by the resistors 18 and 19 is applied to the transistor 9 via the constant voltage diode 12. By controlling the current flowing through the control circuit 4, that is, the field current flowing through the field coil 2, by the operation of the transistor 9, the voltage between the terminals of the output coil 1 is maintained at a substantially constant voltage.

Furthermore, this control circuit includes a base voltage applying circuit 25.
It is equipped with The U-phase positive voltage input to the detection circuit 6 charges a capacitor 37 via a resistor 36 and a diode 29. The charging voltage charged in the capacitor 37 is discharged through the variable resistor 31, the resistor 35, and the gate and cathode of the thyristor 26. Whether the thyristor 26 is conductive or not depends on W connected to the anode side of the thyristor 26.
It depends on the half-wave rectified voltage of the phase and the discharge characteristics of the capacitor 37.

If the capacitor 37 completes discharging before the W-phase half-wave rectified voltage rises, that is, before the positive voltage is applied to the anode side of the thyristor 26,
Thyristor 26 cannot conduct. Furthermore, before the discharge of the capacitor 37 is completed, that is, while a discharge current sufficient to conduct the thyristor 26 is flowing to the gate of the thyristor 26, the W-phase detection voltage becomes positive and is applied to the anode side of the thyristor 26. When this occurs, the thyristor 26 becomes conductive.
The operation of this thyristor 26 is determined by the rotational speed of the generator.

When the engine speed is low, the discharge voltage charged in the capacitor 37 starts discharging as the positive voltage of the U phase decreases, and ends this discharging at a predetermined time. Then, a W-phase voltage appears on the anode side of the thyristor 26. Therefore, in this case, the thyristor 26 will not become conductive. When the thyristor 26 is non-conductive, the W-phase positive detection voltage applied to the anode side of the thyristor 26 is applied to the base of the transistor 9 via the resistor 32, the constant voltage diode 27, the light emitting diode 39, and the diode 28. It becomes like this. As a result, the light emitting diode 39 performs a light emitting operation to notify the user of the light emitting operation. In this case, the base current of the transistor 9 increases compared to when it flows only from the output voltage detection circuit 6 through the constant voltage diode 12, and the time during which the transistor 9 is turned on increases. Therefore, the non-conducting state of the control circuit 4 increases, and the field current flowing into the field coil 2 is suppressed.

As the engine speed increases, the period of one rotation becomes shorter, so the thyristor 26
A W-phase positive detection voltage is now applied to the anode side of the W-phase. By applying this voltage, the thyristor 26 becomes conductive, and the W-phase half-wave rectified voltage applied to the anode side of the thyristor 26 is applied to the thyristor 26.
6 through the anode and cathode to the ground line. Therefore, the base current flowing into the transistor 9 becomes only the current flowing from the detection circuit 6 through the constant voltage diode 12, and as a result, the time during which the control circuit 4 is conducted becomes longer. The field current applied to will be increased.

Next, to explain the protection device for such a control circuit, as shown in Figs. 1 and 2,
This control circuit is formed by mounting circuit components on a printed wiring board 45,
Moreover, this printed wiring board 45 is housed in an exterior case 46 made of synthetic resin. Furthermore, a resin 47 is injected into the outer case 46, thereby enclosing and protecting the circuits on the printed wiring board 45. Therefore, it becomes possible to reliably protect the control circuit of the engine generator.

The variable resistors 31 and 38 that adjust the discharge time constant of the capacitor 37 and the voltage at point A must both be exposed on the outer surface of the resin 47, so that they can be adjusted later. Become. Furthermore, the light emitting diode 39 for indicating non-conduction of the thyristor 26 also needs to be exposed on the outer surface of the resin 47. Accordingly, such parts are mounted on a holder 48 shown in FIGS. 1-4.

A recess 49 is formed on the holder 48,
As shown in FIG. 3, variable resistors 31 and 38 are held within these recesses 49. Note that the lead legs of these variable resistors 31 and 38 extend downward and penetrate the printed wiring board 45.
It is designed to be soldered to the wiring pattern on the back side. Further, a claw 51 is formed at the tip of the leg portion 50 of the holder 48, and the claw 51 is adapted to be engaged with an engagement hole 52 of the printed wiring board 45, whereby the holder 48 is It is designed to be securely held on the printed wiring board 45.
Therefore, the parts 31, 38, 39 on the holder 48 are separated from the printed wiring board 45 while the resin 47
It will be held so that it faces the outer surface of the Note that the fixing of the holder 48 to the printed wiring board 45 is not limited to the above-mentioned claws 51. For example, screw holes may be formed at the tips of the legs 50 and the holder 48 may be fixed with one or several screws. good.

Therefore, according to the circuit protection device according to this embodiment, there is no need to attach tubes to the lead legs of the components 31, 38, and 39, and there is no difficulty in attaching them to the printed circuit board 45. Further, since these parts 31, 38, and 39 are held by the holder 48, these parts will not move before the resin 47 is injected, and their positioning will be ensured. In addition, when transporting the printed circuit board 45, these parts 31, 3
It is possible to reliably prevent an accident in which force is applied to the lead legs 8 and 39 and the lead legs are cut off.
Further, the holder 48 that holds such parts can be used as a guide means for the lead wires to be drawn out, thereby making it possible to fix the position at which the lead wires are drawn out.

〓Effects of the invention〓 As described above, the present invention provides a holder for holding circuit components arranged so as to face the outer surface of the resin.
The legs of this holder are supported by the circuit board, and the circuit components on the holder are held apart from the circuit board. Therefore, according to such a configuration, it is possible to easily attach the circuit components arranged so as to face the outer surface of the resin, and to ensure their positioning.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a protection device for a control circuit of an engine generator according to an embodiment of the present invention;
is a longitudinal sectional view of the same, Fig. 3 is an enlarged sectional view of the main part showing the holding of the variable resistor, Fig. 4 is an enlarged longitudinal sectional view showing the installation of the holder, Fig. 5 is a circuit diagram of the control circuit, and Fig. 6 is an enlarged sectional view of the main part. FIG. 7 is a perspective view of the external appearance of a conventional protection device, and a vertical cross-sectional view of a main part showing the support structure of the variable resistor. In addition, in the symbols used in the drawings, 31...variable resistor, 38...variable resistor, 39...light emitting diode, 45...printed wiring board, 46...exterior case, 47...resin, 48...holder, 50 ……
Leg portions, 51...claws, 52...engaging holes.

Claims (1)

[Scope of utility model registration request] In an apparatus in which circuit components are mounted on a circuit board to form a predetermined circuit, and the circuit board is inserted into an exterior case and sealed with resin, the circuit board is arranged so as to face the outer surface of the resin. a holder for holding a circuit component, the legs of the holder are supported by the circuit board;
A circuit protection device characterized in that the circuit components on the holder are held in a state separated from the circuit board.