JP2009099509A - Resistor with built-in temperature fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that a conventional resistor with a built-in temperature fuse requires labor and cost when mounted in low-back use and the melt-down of temperature fuse possibly causes the breakage, malfunction or instability of an electric circuit device to which no power is supplied. <P>SOLUTION: In the resistor, a series connecting body consisting of a resistance element 1 and a temperature fuse 2 is stored in a box-shaped ceramic case 3 having an opening portion, lead terminals 1b, 2b of the series connecting body are drawn out of grooves 3b, 3c of the ceramic case 3, and resin type cement 4 is used for sealing the opening portion 3a of the ceramic case. The two lead terminals drawn out of the grooves of the ceramic case are bent at right angle in the same direction. Near the side face of the ceramic case on the side opposed to the two lead terminals, a new lead terminal 5 is provided to be connected to the lead terminal 1a or the lead terminal 2a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resistor with a built-in thermal fuse.

  Resistors with built-in thermal fuses are used for electrical circuit devices to shut down the circuit when abnormal heat is generated due to overcurrent, etc., and to prevent fire accidents as shown in FIGS. 3 (a) and 3 (b). The thing of a simple structure is used widely. (See Patent Document 1 for related literature.)

  3A and 3B, the resistance element 1 and the thermal fuse 2 are juxtaposed and housed in a ceramic case 3 that is box-shaped and has an opening 3a on one side surface. In addition, the lead terminals 1a and 2a on one end side of the resistance element 1 and the thermal fuse 2 are connected, and the lead terminals 1b and 2b on the other end side are formed from grooves 3b and 3c carved on the side surface of the ceramic case 3, respectively. Has been pulled out. The opening of the ceramic case 3 is sealed with a resin type cement 4.

  The principle of operation of the resistor with a built-in thermal fuse having such a structure (hereinafter sometimes simply referred to as “resistor”) is as follows.

When an overcurrent flows, the resistance element is overheated, and a part of the generated heat is transmitted to the adjacent thermal fuse. When the temperature of the thermal fuse rises due to the propagated heat and reaches the fusing temperature, the fuse is blown, and the current is cut off between the two lead terminals 1b, 2b drawn from the ceramic case.
Patent Publication 2007-103687

  When attaching the resistor to the board, conventionally, a method of inserting the lead terminal vertically into the board hole is generally used. As shown in FIG. This limited the reduction in size and height of the circuit device.

  As a countermeasure for reducing the height, a method of attaching a resistor to a substrate by bending a lead terminal at a right angle as shown in FIG. 5 (hereinafter, this mounting method is sometimes referred to as “use of a low profile”) has increased in recent years. However, in such a case, the component main body is greatly shaken with respect to the vibration with the board fixing portion of the lead terminals 1b and 2b as a fulcrum, and in the worst case, the lead terminal may be broken due to metal fatigue or the like. .

  Therefore, when using a low profile, once the resistor is attached to the substrate, an industrial bond or auxiliary component is used near the side surface of the ceramic case 3 facing the lead terminals 1b and 2b shown in FIG. Thus, it is necessary to fix the parts so that they do not vibrate, which causes an increase in assembly man-hours and a stagnant production efficiency.

  Also, in an electrical circuit device, if the temperature fuse is blown due to abnormal heat generation due to overcurrent, etc., control is performed via a resistor, for example, due to the property that no current flows in the circuit after this resistor on the current path. In a circuit where power is supplied to the circuit, when the temperature fuse is blown and the power supply is stopped, the electric circuit device becomes uncontrollable and may cause damage, abnormal operation, instability, and the like.

  The present invention is intended to solve the problems of such a conventional resistor, simplification of assembly when using a low profile, and damage, abnormal operation of the electric circuit device as described above, The object is to provide a resistor that can avoid instability.

  To achieve the above object, according to the present invention, a series connection body of a resistance element and a thermal fuse is accommodated in a box-shaped ceramic case having an opening, and a lead terminal of the series connection body is used as the ceramic case. In a resistor that uses a resin-type cement to seal the ceramic case opening, the two lead terminals drawn from the ceramic case groove are bent at right angles in the same direction. A new lead terminal is provided in the vicinity of the side surface of the ceramic case on the side facing the book lead terminal, and this terminal is electrically connected to the connecting portion of the resistance element and the thermal fuse.

  By soldering the newly provided lead terminal and two conventional lead terminals drawn out of the ceramic case from the connection part of the resistance element and the thermal fuse, the resistor has at least three points on the board when used in low profile Fixed. That is, in FIG. 1 showing the resistor of the present invention, the newly provided lead terminal 5 and lead terminals 1b and 2b are fixed to the substrate. As shown in FIG. 2, the fixing form is stably fixed on the substrate 6, so that fixing work using industrial bonds and auxiliary parts is not required, and the attachment to the substrate can be simplified.

  Further, for example, the following usage method can be devised by utilizing the newly provided lead terminal drawn out of the ceramic case from the connecting portion of the resistance element and the thermal fuse. In the lead terminals 1b, 2b and 5 shown in FIG. 1, if the lead terminal 1b is used as an input and a circuit requiring constant power is connected to the lead terminal 5 and a circuit to be cut off at the time of abnormality is connected to the lead terminal 2b, Even if the thermal fuse is blown and the lead terminals 1b and 2b are cut off, the lead terminals 1b and 5 are connected via the resistance element so that power can be continuously supplied. While taking advantage of the original function, it is possible to avoid breakage, abnormal operation, and instability of the electric circuit device, and it is possible to easily construct a multi-function and high added value electric circuit device.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  1A, 1B, and 1C are examples of embodiments of the present invention.

  The resistance element 1 and the thermal fuse 2 are juxtaposed and housed in a ceramic case 3 that is box-shaped and has an opening 3a on one side surface. The opening 3 a is sealed with a resin type cement 4.

  The lead terminals 1a and 2a on one end side of the resistance element 1 and the thermal fuse 2 are connected, and a lead terminal 5 is further connected to 1a. The lead terminal 5 is connected to the opening surface from the opening 3a of the ceramic case 3. It is drawn out of the resin type cement 4 in the vertical direction. The lead terminals 1 b and 2 b on the other end side of the resistance element 1 and the thermal fuse 2 are drawn out from the grooves 3 b and 3 c carved in the side surface of the ceramic case 3 so as to be in the same direction as the axial direction of the lead terminal 5. , Each is bent.

  The connection of the lead terminal 5 is not limited to the lead terminal 1a but may be connected to the lead terminal 2a, and the connection position is not limited in the range of the lead terminals 1a and 2a. The connection method may be any of welding, soldering, and caulking.

  Also, a plurality of lead terminals 5 having the same shape may be provided. In this case, as long as at least one lead terminal 5 is connected to the lead terminal 1a or the lead terminal 2a, the other is not necessarily connected. That is, the lead terminal that is not connected to either of the lead terminals 1a and 2a functions only for fixing the resistor, and the lead terminal connected to the lead terminal 1a or 2a is for solving the problems in the present invention. Functions as a means.

  Further, the method of pulling out the lead terminal 5 from the ceramic case 3 is not limited to pulling out from the ceramic case opening 3a, but the same method as the lead terminal 1b or 2b, that is, a groove is formed on either side of the ceramic case 3. A method of chopping and pulling out from this groove may be used.

(A) is a partially broken front view of the resistor with a built-in thermal fuse of the present invention, (b) is a perspective view of (a) (no breakage), (c) is (a) or (b) The perspective view of the serial connection body of the resistance element and thermal fuse which are used for is shown. (A) is the perspective view of the state which attached the temperature fuse built-in type resistor of this invention to the board | substrate, (b) shows the side view. (A) is a front view of a conventional resistor with a built-in thermal fuse, and is a partially broken view, and (b) is a perspective view (no breakage). The perspective view of the state which attached the conventional temperature fuse built-in type resistor to the board | substrate by the general method is shown. (A) is the perspective view of the state which attached the conventional resistor with a built-in temperature fuse to the board | substrate by low profile use, (b) shows the side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resistive element 1a Resistive element lead terminal 1b Resistive element lead terminal 2 Thermal fuse 2a Thermal fuse lead terminal 2b Thermal fuse lead terminal 3 Ceramic case 4 Resin-type cement 5 Lead terminal 6 Substrate

Claims (1)

  A series connection body of a resistance element and a thermal fuse is accommodated in a box-shaped ceramic case having an opening, and a lead terminal of the series connection body is drawn out from a groove provided in the ceramic case, thereby sealing the ceramic case opening. Therefore, in the resistor using resin-type cement, the two lead terminals drawn out from the groove of the ceramic case are bent at right angles in the same direction, respectively, and near the side surface of the ceramic case on the side facing the two lead terminals And a new lead terminal, and this terminal is electrically connected to the connecting portion of the resistance element and the thermal fuse.

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