JP3224516B2 - Terminal box - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal box particularly suitable for use in electric wiring of explosion-proof equipment.

[0002]

2. Description of the Related Art Conventionally, for example, a plant apparatus in which an electric signal line is arranged in an environment filled with a flammable gas is used when a connection portion of the electric signal line or an electronic component is ignited by contact with an environmental gas. However, it has an explosion-proof structure that does not allow the flame to escape to the outside, and an explosion-proof terminal box is used for its electrical wiring.

FIG. 4 shows an example of such a conventional terminal box.
2 shows a terminal box 50 used for electric wiring of the electropneumatic positioner P. The positioner P opens and closes the air valve by controlling the air pressure for driving the air valve according to the electric signal from the controller. The terminal box 50 of the present example is used for wiring the electric signal. Used.
The terminal box 50 has a box body 51 attached to the positioner P, and a terminal block 52 attached inside the box body 51. The terminal block 52 has a pair of fixed terminals 5 of opposite polarity.
3 and 54 are provided, and the upper fixed terminal 5 in FIG.
3 is a plus pole, and the lower fixed terminal 54 in the figure is a minus pole. These fixed terminals 53, 54
Is connected to the positioner P by an internal electric wire (not shown) wired below the terminal block 52.

On the peripheral wall of the box body 51, first and second two conduit connection ports 51A and 51B are provided at a position shifted by about 90 degrees in the circumferential direction, and these connection ports 51A and 51B are provided with: The cap 55 or the conduit 56 is selectively screwed. In FIG. 4, a cap 55 is screwed onto the first conduit connection port 51A to close the connection port 51A, while the second conduit connection port 5A is closed.
A conduit 56 is screwed to 1B, and a pair of external electric wires 57 and 58 are drawn into the box body 51 through the conduit 56. Further, according to the mounting posture of the positioner P, the cap 55 is screwed to the second conduit connection port 51B, and the connection port 51B
Is closed, and the conduit 5 is connected to the first conduit connection port 51A.
6, the pair of external electric wires 57, 58 can be drawn into the box body 51 through the electric conduit 56.

The external electric wire 57 has a positive pole, and a terminal 57A at the tip thereof is attached to the fixed terminal 53 by a screw 61 and connected thereto. The external electric wire 58 has a negative polarity, and a terminal 58A at the tip thereof is attached to the fixed terminal 54 by a screw 62 and connected thereto. External wires 57, 58
Are connected to a controller (not shown), and the positioner P is connected to these external wires 57 and 58 and the fixed terminal 5.
An electric signal is input from the controller through the switches 3 and 54, and the air pressure for driving the air valve is controlled according to the electric signal.

Next, the operation will be described. In such a terminal box 50, any one of the first and second conduit connection ports 51A and 51B can be selected as a position where the external electric wires 57 and 58 are drawn in according to the mounting posture of the positioner P or the like. In addition, when working on electrical wiring using such a terminal box 50, it is necessary to pay close attention to explosion protection. For example, an electrical connection portion, that is, a connection portion between the internal wiring (not shown) and the fixed terminals 53 and 54,
In addition, it is necessary to avoid wiring in which stress due to external force is concentrated on the connection between the external wires 57 and 58 and the fixed terminals 53 and 54. Therefore, the terminal lengths of the external wires 57 and 58 are varied in advance in consideration of the positional relationship between the terminal block 52 and the conduit connection ports 51A and 51B. For example, when the external electric wires 57 and 58 are drawn through the second conduit connection port 51B as shown in FIG.
1B along the vertical center line in FIG.
In consideration of the positional relationship in which the wires 54 are arranged vertically, the processing length of the terminal of the external wire 57 on the positive pole side is set longer than the external wire 58 on the negative pole side as shown in FIG.

FIG. 6 shows another example of the structure of the terminal box 50 used for electric wiring of the electropneumatic positioner P similar to FIG. 6, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In this example, the fixed terminal 53,
The stress is concentrated on the electrical connection portions between the internal wires 63, 64 on the positioner P side and the fixed terminals 53, 54 by forming the terminal 54 into a substantially L-shaped plane or the terminal block 52 having a complicated shape. You are avoiding that.

[0008]

In the conventional terminal box 50 constructed as described above, the one shown in FIG. 4 first has a conduit connection port 51A, in order to avoid stress concentration at the electrical connection portion. The processing length of the ends of the external wires 57 and 58 has to be changed according to which of the wires 51B the external wires 57 and 58 are drawn from. This is because the positional relationship between the first conduit connection port 51A and the fixed terminals 53 and 54 is different from the positional relationship between the second conduit connection port 51B and the fixed terminals 53 and 54.

That is, when the external electric wires 57 and 58 are drawn through the second conduit connection port 51B as shown in FIG. 4, it is fixed to the vertical direction in FIG. 4 where the center line of the conduit connection port 51B extends. Since the arrangement direction of the terminals 53 and 54 coincides with each other, as shown in FIG.
The processing length of the terminal 7 may be set to be longer than that of the external electric wire 58 on the minus pole side. However, the first conduit connection port 51
When the external electric wires 57 and 58 are drawn in through A, since the horizontal direction in FIG.
The processing length of the terminals of the external wires 57, 58 must be changed in consideration of the positional relationship, and the external wires 57, 58 shown in FIG.
8 cannot be used as it is. When the processing length of the terminal of the external electric wires 57 and 58 is changed in this manner, there is a problem that work such as stripping of the electric wire covering is required again, which causes deterioration of workability.

On the other hand, in the configuration of FIG. 6, the shape of the terminal block 52 and the fixed terminals 53 and 54 becomes complicated, so that
There has been a problem that the overall size and cost are increased.

[0011] The present invention was to solve the problem as above Symbol
Terminal block with multiple fixed terminals
Built-in, draw in external wires to be connected to its fixed terminals
Terminal box with two connection ports opened in a substantially right angle direction
Then, pull the external electric wire from either of the two connection ports.
Even when writing, changing the end-terminal processing length of the external electric wire
Can be connected to the fixed terminal without
Specific connection portion can avoid stress concentration, Rutotomoni can improve the workability of connecting external wires, it is not necessary to complicate the fixed terminal and the terminal block shape, size of the terminal box itself It is another object of the present invention to obtain a terminal box capable of reducing the cost.

[0012]

A terminal box according to the present invention has a terminal having a plurality of fixed terminals to which an external electric wire is to be connected.
Draw the external wire into the box body with the table mounted inside.
First and second connection ports that can be
Open the core so that it is at an angle of about 90 degrees.
The external electric wire drawn in from one of the connection ports is
In a terminal box connected to a fixed terminal, the first connection port
Through the intersection of the center line of the second connection port and the center line of
On the line that bisects the approximately 90 degree angle formed by those center lines
Connection of an external electric wire at each of the fixed terminals
The parts are arranged .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The terminal box of the present example is an example of application as a terminal box used for electric wiring of the electropneumatic positioner P similar to that of the above-described conventional example.

FIG. 1 is a schematic configuration diagram of a positioner P having a terminal box 10 of the present embodiment. In positioner P, 1
Is a circuit board on which a control circuit is configured by a CPU, a memory, and the like. The electropneumatic converter 2 controls the operating pressure introduced from the air pressure supply source 3 to the pilot relay 4 according to a control signal from the control circuit. The air valve 5 is opened and closed by the air pressure introduced from the pilot relay 4 to the air valve 5, and the opening and closing amount is detected by the angle sensor 6 and fed back. As the angle sensor 6, a potentiometer, an MR (magnetic resistance) sensor, or the like is used.

The terminal box 10 of this embodiment is formed below such a positioner P, and the box body 11 is integrated with the body of the positioner P. A terminal board 12 is mounted inside the box body 11, and a cover 13 is screwed into a lower opening of the box body 11. Terminal box 10
Electrically connects external wires 14 and 15 connected to a controller (not shown) and internal wires 16 and 17 connected to the circuit board 1 as described later. Positioner P
The control circuit on the circuit board 1 controls the electropneumatic converter 2 based on an electric signal input from the controller through the terminal box 10.

FIGS. 2 and 3 show such a terminal box 10.
FIG. 2 is a bottom view for explaining an example of the configuration inside the box body 11 of FIG. Fixed terminals 19 and 20 of opposite poles are arranged on the terminal block 18 so as to be arranged along a virtual straight line L0, and screwing positions of screws 24 and 25 described later are positioned on the straight line L0. I have. The fixed terminal 19 on the upper right side in FIG. 2 has a positive pole, and the fixed terminal 20 on the lower left side in FIG. 2 has a negative pole. These fixed terminals 19 and 20 are connected to internal electric wires 16 and 17 (FIG. 1)
) Is connected to the positioner P side.

The first and second two conduit connection ports (connection ports) 11A and 11B are formed on the peripheral wall of the box body 11 in the circumferential direction.
They are offset by 0 degrees. L1 and L2 are virtual centerlines of these conduit connection ports 11A and 11B, and they form 90 degrees with respect to the intersection P0. The straight line L0 is an angle (90 degrees) formed by the center lines L1 and L2.
Is a bisector. Conduit connection ports 11A, 11B
, The cap 21 or the conduit 22 is selectively screwed, and the threaded portions of the cap 21 and the conduit 22 are set to have a depth L or the like so as to meet explosion-proof standards. I have.

In FIG. 2, the first conduit connection port 11
A is screwed on the cap 21 so that the connection port 11A
Is closed. On the other hand, the conduit 22 is screwed into the second conduit connection port 11 </ b> B, and the pair of external electric wires 14 and 15 is drawn into the inside of the box body 11 through the conduit 22. The inside of the conduit tube 22 through which the external electric wires 14 and 15 are passed is sealed with a sealing material 23. Further, depending on the mounting posture of the positioner P, as shown in FIG. 3, the cap 21 is screwed to the second conduit connection port 11B to close the connection port 11B, while the first conduit pipe is closed. The conduit 22 is screwed to the connection port 11A, and the conduit 2
The pair of external electric wires 14 and 15 can be drawn into the inside of the box main body 11 through 2.

The external electric wire 14 has a positive pole, and a terminal 14A at the tip thereof is attached to the fixed terminal 19 by a screw 24 and connected thereto. The external electric wire 15 has a negative pole, and a terminal 15A at the tip thereof is attached to the fixed terminal 20 by a screw 25 and connected thereto.

Next, the operation will be described. Terminal box 10
Is the first, depending on the mounting posture of the positioner P, etc.
Either of the second conduit connection ports 11A and 11B can be arbitrarily selected as the position where the external electric wires 14 and 15 are drawn. At this time, since the straight line L0 is a bisector of the angle formed by the center lines L1 and L2, the positional relationship between the first conduit connection port 11A and the fixed terminals 19 and 20 and the second conduit The positional relationship between the connection port 11B and the fixed terminals 19 and 20 is symmetric with respect to the straight line L0. Therefore, the case where the external electric wires 14 and 15 are drawn in from the first conduit connection port 11A and the case where the external electric wires 14 and 15 are drawn from the second conduit connection port 11B.
When the wire 5 is pulled in, the concentration of stress at the electrical connection portion can be avoided without changing the processing length of the terminals of the external wires 14 and 15.

In the case of this example, the external electric wire 14 on the positive pole side
Are set longer than the external wires 15 on the negative pole side, so that these external wires 14, 15
Is drawn in from either of the first and second conduit connection ports 11A and 11B, it is possible to avoid stress concentration at the electrical connection portion. As described above, since there is no need to change the processing length of the terminals of the external electric wires 14 and 15, the workability of wiring is improved.

Further, it is possible to avoid the stress concentration at the electrical connection portion without particularly complicating the shapes of the terminal block 18 and the fixed terminals 19 and 20, thereby reducing the size of the terminal box 10 as a whole. The price can be reduced.

The terminal box of the present invention is not specific only to the electric wiring of the positioner P, for example, industrial transmitters like site type used in a severe working environment, as terminal box for various electrical appliances Can be widely applied.

[0024]

As described above , according to the present invention, a plurality of
Built-in terminal block with fixed terminals
First and second enabling the external wires to be drawn in
In a terminal box having a connection port formed at an angle of about 90 degrees,
The center line of the first connection port and the center line of the second connection port
Pass through the intersection and make an angle of approximately 90 degrees between
On the dividing line, the outside of each of the fixed terminals
Since the connection part of the external electric wire is configured to be arranged, the first
The external wire from the connection port to the external wire connection of the fixed terminal
Pull-in length and external wire of fixed terminal from second connection port
Approximately equal the lead-in length of the external wire to the connection
be able to. For this reason, connect the external electric wire from the first connection port.
External between the case of pulling in and the case of pulling in from the second connection port
Without changing the terminal treatment length of the wire,
External wires can be easily connected,
The stress concentration on the electrical connection can be avoided,
There is an effect that connection workability of the external electric wire is improved. I
The fixed terminals and terminal blocks need to have a special shape and configuration.
There is no need to reduce the size and cost of the terminal box itself.
There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a positioner that can be equipped with a terminal box of the present invention.

FIG. 2 is a partially cutaway bottom view of a main part of the terminal box according to the embodiment of the present invention in a state where external electric wires are connected.

FIG. 3 is a bottom view of a main part in another connection state of the external wires of the terminal box according to the embodiment of the present invention.

FIG. 4 is a bottom view of an essential part for explaining an example of a conventional terminal box.

FIG. 5 is a plan view of a terminal portion of the external electric wire of FIG. 4;

FIG. 6 is a partially cutaway bottom view for explaining another example of the conventional terminal box.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Terminal box 11 Box main body 11A 1st conduit connection port (1st connection port) 11B 2nd conduit pipe connection port (2nd connection port) 12 Terminal board 13 Cover 14, 15 External electric wire 16, 17 Inside Wire 18 Terminal block 19, 20 Fixed terminal 21 Cap 22 Conduit tube 23 Seal material 24, 25 Screw L1, L2 Center line L0 Straight line (bisector)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 5/22 H02K 5/136

Claims (1)

(57) [Claims] 1. A terminal block having a plurality of fixed terminals such as different poles.
Is attached to the inside of the box body and the peripheral wall of this box body.
Provided, wherein the external wire to be connected to the each fixed terminal
First and second connection ports to be retractable into the box body
And connecting the first and second connection ports to respective center lines.
Center but is opened so that the angle of approximately 90 degrees, in the terminal box for connecting the Kigai section wires before drawn that from one of the connection port prior Symbol fixed terminal, said first connection port Line and center line of the second connection port
Through the intersection of
On each of the fixed terminals on a line bisecting
A terminal box in which a connection portion of an external electric wire is arranged.