JP6616465B2 - Fixed resistor - Google Patents

Description

  The present invention relates to a fixed resistor.

  Conventionally, a fixed resistor using a flat plate resistor element has been used. This type of fixed resistor is, for example, a plate resistor element in which a pair of terminals (20) are mounted in a ceramic case (80) like a fixed resistor (1) shown in Patent Document 1 (see particularly FIG. 1). 10) is stored, and then the ceramic case (80) is filled with a filler (90) and solidified. The pair of terminals (20) project outwardly in a straight line from the narrow outer peripheral side wall of the rectangular parallelepiped ceramic case (80). The fixed resistor (1) is attached to the circuit board by placing the surface (outer peripheral wall) of the ceramic case (80) protruding the terminal (20) on the circuit board. In other words, the fixed resistor (1) is installed upright so that both opposing large-surface areas of the ceramic case (80) rise vertically on the circuit board. For this reason, the height of the fixed resistor (1) from the circuit board becomes high, the problem that the height dimension of the circuit board on which the fixed resistor (1) is mounted cannot be reduced, and the mounting state is unstable. There was a problem of becoming.

  In order to solve the above problem, for example, as shown in Patent Document 2 (see FIGS. 1 to 4 and 6 in particular), a concave storage portion (11) provided on one surface of the case (10) having a large area. The plate resistance element (30) is housed inside, and then the filler (90) is filled and solidified, and the terminals (45) and (47) protruding from the outer peripheral side wall of the case (10) are bent downward. What is necessary is just to use the comprised fixed resistor (1). The fixed resistor (1) is attached to the circuit board (100) by placing the fixed resistor (1) so that the surface filled with the filler (90) faces the surface of the circuit board (100). In other words, the fixed resistor (1) has a large surface of the case (10) facing the circuit board (100), so that the height of the mounted fixed resistor (1) from the circuit board (100) is increased. The height of the circuit board (100) on which the fixed resistor (1) is mounted can be reduced, and the mounting state is stabilized.

JP 2000-150201 A JP 2010-34483 A

However, the fixed resistor (1) described in Patent Document 2 also has the following problems.
That is, in the fixed resistor (1) described in Patent Document 2, the tips of the terminals (45) and (47) are placed toward the side where the plate resistance element (30) is accommodated and the filler (90) is filled. Since it protrudes, the force that prevents this when the terminals (45) and (47) are pulled in the pulling direction (circuit board direction) causes the filler (90) in the recess (11) to peel off. Since it was only the strength to prevent, it could not be said that the pullout strength was strong. In order to increase the pull-out strength, for example, as in the fixed resistor 200 shown in FIG. 9 of the present application, the housing portion 211 of the case 210 is provided on the upper surface side of the case 210, and the plate resistance element 230 is placed in the housing portion 211. In this case, the tip of the terminal 250 attached to the plate resistance element 230 is inserted into the terminal insertion hole 215 provided on the lower surface 213 of the case 210 and protrudes to the lower surface side of the case 210. In this state, the storage portion 211 is stored. What is necessary is just to set it as the structure filled with the filler 270 inside. With this configuration, the pulling strength is high because the lower surface 213 of the case 210 is located below the plate resistor 230 when the terminal 250 is pulled in the pulling direction (downward in FIG. 9).

  However, in the fixed resistor 200 having such a structure, when the fixed resistor 200 is assembled, the terminal 250 attached to the plate resistor element 230 must be inserted into the small terminal insertion hole 215 provided in the case 200 without error. Therefore, there are cases where the insertion is not performed properly, and there is a problem that the assembly workability is poor. In addition, when the inner diameter of the terminal insertion hole 215 is increased, another problem that the filler 270 filled from the gap between the terminal 250 and the terminal insertion hole 215 leaks occurs.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a fixed resistor that can increase the pull-out strength of a terminal and can be easily assembled.

The present invention relates to a fixed resistor mounted on a circuit board and projecting a terminal toward a board facing surface which is a face facing the circuit board. And a filling material filled in the element housing portion of the case, and the resistance element is provided on an outer peripheral side wall adjacent to the substrate facing surface of the case. The terminal is bent at a portion protruding from the resistance element so that the terminal protrudes toward the substrate facing surface side of the case , and the fixed resistor is projected from the upper surface side. In this case, the terminal is within the projected area of the case .
According to the present invention, since the resistance element is inserted from the insertion port provided in the outer peripheral side wall of the case, it is not necessary to provide a small terminal insertion hole in the case and pass the terminal through this. The insertion operation into the element storage portion is facilitated, and the fixed resistor can be easily assembled. Further, the terminal can be easily projected from the surface of the case facing the substrate.
Further, since the wall on the substrate facing surface side of the case is interposed between the terminal projecting from the substrate facing surface of the case and the resistance element, the pulling strength of the projecting terminal can be increased.

According to another aspect of the present invention, there is provided a fixed resistor that is placed on a circuit board and projects a terminal toward a board facing surface that is a face facing the circuit board. A case having an element accommodating portion for accommodating an element; and a filler filled in the element accommodating portion of the case; and the resistance element is provided on an outer peripheral side wall adjacent to the substrate facing surface of the case. The terminal is bent at a portion protruding from the resistance element so that the terminal protrudes toward the substrate facing surface side of the case , and further , a side of the side surrounding the insertion opening of the case is inserted. The side on the substrate facing surface side is characterized in that its height position is formed lower than the other sides.

  In addition to the above features, the present invention provides a leg for forming a clearance for air flow between the fixed resistor and the circuit board when the fixed resistor is placed on the circuit board on the board-facing surface of the case. It is characterized by providing a section.

  According to the present invention, the pull-out strength of the terminal can be increased, and at the same time, the fixed resistor can be easily assembled.

It is the perspective view which looked at the fixed resistor 1 from the upper side. It is the perspective view which looked at the fixed resistor 1 from the lower side. FIG. 6 is an explanatory diagram of an assembly method of the fixed resistor 1. It is AA sectional drawing of FIG. It is the perspective view which looked at the case 10 from the upper side. It is the perspective view which looked at the case 10 from the lower side. FIG. 6 is an explanatory diagram of an attachment method for attaching the fixed resistor 1 to the circuit board 100. FIG. 6 is an explanatory diagram of an assembly method of the fixed resistor 1. 2 is a schematic cross-sectional view of a fixed resistor 200. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a fixed resistor 1 according to an embodiment of the present invention as viewed from above, FIG. 2 is a perspective view of the fixed resistor 1 as viewed from below, and FIG. 4 and 4 are cross-sectional views taken along line AA of FIG. As shown in FIG. 3, the fixed resistor 1 includes a resistance element (hereinafter referred to as “plate resistance element”) 50 having a pair of terminals 80, 80 attached to the element storage portion 11 from the insertion port 13 provided in the case 10. The element storage unit 11 is filled with a filler 90 while being inserted and stored. In the following description, “upper” refers to the direction of viewing the fixed resistor 1 placed on the surface of the circuit board 100 (see FIG. 7) described below, and “lower” refers to the opposite direction. And

  FIG. 5 is a perspective view of the case 10 as viewed from above, and FIG. 6 is a perspective view of the case 10 as viewed from below. As shown in these drawings, the case 10 has a rectangular shape with a small thickness in the vertical direction and a large area in the horizontal direction. The case 10 is provided with an element accommodating portion 11 for accommodating the plate resistor element 50 therein. An insertion port 13 connected to the element storage portion 11 is provided on one side wall of the outer periphery. Case 10 is manufactured by firing ceramics. At the four corners of the lower surface of the case 10, leg portions 15 having the same height and made of small protrusions protruding downward are provided. The lower surface of the case 10 provided with the legs 15 is a substrate facing surface 17 on the side facing the circuit substrate 100 described below. In addition, four surfaces adjacent to the substrate facing surface 17 of the case 10 (in other words, surfaces other than the substrate facing surface 17 and the opposite surface facing it) are referred to as outer peripheral side walls.

  Of the four sides around the insertion opening 13 of the case 10, the side 19 on the substrate facing surface 17 side has a lower height than the other three sides. Further, a pair of concave terminal positioning portions 21, 21 into which the bent tip side portions of a pair of terminals 80 described below are respectively inserted are provided at positions near both ends of the side 19. The width dimension of the recessed part which comprises the terminal positioning part 21 is formed in the dimension larger than the diameter dimension of the terminal 80 mentioned below. Further, the distance between the terminal positioning portions 21 is formed substantially the same as the distance between a pair of terminals 80 described below. The positions of the side 19 and the terminal positioning portion 21 whose height position is lower than the other three sides may be changed according to the position where the terminal 80 protrudes. In some cases, the position of the side 19 may be the same height as the other three sides, or may be a position protruding from these three sides. Further, in this example, the terminal positioning portion 21 is configured by a concave portion, but may be any shape as long as the terminal 80 can be positioned, for example, the same surface as the side 19 and only the left and right outer walls. Positioning may be performed.

  On the inner peripheral surface of the element storage portion 11 of the case 10, the insertion of the plate resistance element 50 is guided in the direction along the insertion direction B of the plate resistance element 50 described below, and the positioning of the plate resistance element 50 in the thickness direction is guided. Guide / positioning projections 23 are provided at three locations. The two guide / positioning projections 23 are provided at the left and right end positions of the inner peripheral surface on the upper surface side in the element housing portion 11, and the other guide / positioning projection 23 is disposed on the lower surface side in the element housing portion 11. It is provided at the center position of the inner peripheral surface. That is, the upper and lower guide / positioning protrusions 23 are provided alternately. Each guide / positioning protrusion 23 is formed in a substantially rectangular shape elongated in the insertion direction B, and an end surface on the insertion port 13 side is a tapered surface 25. Each taper surface 25 is inclined so as to recede toward the back side (direction in which the resistance element 50 is inserted) of the element storage portion 11 as it protrudes from the inner peripheral surface of the element storage portion 11. Further, as shown in FIG. 4, the height dimension of the upper and lower guide / positioning projections 23 is such that when the planar plate resistance element 50 is accommodated between them, the plate resistance element 50 is in the thickness direction of the element accommodating portion 11. It is formed in the dimension positioned at the approximate center position.

  As shown in FIG. 3, the plate resistance element 50 is configured by providing a plurality of linear or dotted resistance value adjustment notches 51 in a substantially rectangular resistance plate. The shape of the resistance value adjusting notch 51 is not limited to the shape shown in FIG. 3, and may be formed in various other shapes. As a material of the resistance plate constituting the plate resistance element 50, various resistance materials such as a copper nickel alloy, a nickel chromium alloy, and an iron chromium alloy can be used.

  In the vicinity of the left and right sides of the plate resistor element 50, a pair of terminals 80, 80 are attached in parallel by spot welding or the like. Both terminals 80, 80 are bent at a portion protruding from one side of the plate resistance element 50, with the tip side portion bent at a right angle. The bending direction of the terminal 80 is the side 19 side of the case 10, that is, the substrate facing surface 17 side. As a material of the terminal 80, for example, copper, iron, or other conductive material is used.

The filler 90 is composed of a heat-resistant insulating material, and in this embodiment, heat-resistant silicon cement (silica [SiO ₂ ] and silicon varnish [silicon resin] made into a paste form with a solvent [xylene or the like]) is used. .

  In order to manufacture the fixed resistor 1, as shown in FIG. 3, the plate resistor element 50 is inserted into the element housing portion 11 of the case 10 from the insertion port 13. At this time, the plate resistance element 50 is smoothly inserted between the three guide / positioning protrusions 23 by the tapered surfaces 25 of the three guide / positioning protrusions 23. At the same time, as shown in FIG. 4, the plate resistance element 50 is positioned at a substantially central position in the thickness direction in the element housing portion 11 by the three guide / positioning projections 23. That is, the guide / positioning protrusion 23 guides the insertion of the plate resistance element 50 to smoothly insert the plate resistance element 50 into the element housing portion 11 of the case 10 and positions the plate resistance element 50 in the thickness direction.

  Then, the bent base end portions of the pair of terminals 80 are respectively inserted into the pair of terminal positioning portions 21. By inserting the terminal 80 into the terminal positioning portion 21, the plate resistor element 50 can be easily positioned in the insertion direction (depth direction of the element storage portion 11) and in the left-right direction. At the same time, both terminals 80, 80 protrude outward from the substrate facing surface 17 side of the case 10. As described above, the terminal 80 is bent at the portion protruding from the plate resistance element 50, and the bent tip side portion of the terminal 80 is positioned at the terminal positioning portion 21, so that the terminal 80 can be easily separated from the board facing surface 17 of the case 10. The terminal 80 and the plate resistance element 50 fixed to the terminal 80 can be positioned at the same time.

  And the filling material 90 is filled in the element accommodating part 11 with an automatic filling machine, for example. At this time, the filling amount of the filler 90 is up to the innermost part of the terminal positioning portion 21 (the bottom surface 21a in FIG. 3), as shown in FIG. This is to prevent the filled filler 90 from protruding from the terminal positioning portion 21 to the outside of the case 10. Then, the surface of the filled filler 90 is pressed with a pressing member (not shown) to flatten the surface. When the entire case 10 filled with the filler 90 is heated (for example, 180 ° C., 1 hour) to solidify the filler 90, the fixed resistor 1 shown in FIGS. 1 and 2 is completed. The above assembling procedure is an example, and it goes without saying that the assembly may be performed using other various assembling procedures.

  FIG. 7 is an explanatory view of an attachment method for attaching the fixed resistor 1 configured as described above to the circuit board 100. As shown in the figure, the fixed resistor 1 is placed on the circuit board 100 with the board facing surface 17 from which the terminals 80 protrude facing down. At this time, the lower surface of each leg portion 15 of the fixed resistor 1 abuts on the circuit board 100, thereby forming a gap for air circulation between the fixed resistor 1 and the surface of the circuit board 100. At the same time, the pair of terminals 80, 80 are inserted into the pair of terminal insertion holes 101, 101 provided in the circuit board 100, and the terminals 80, 80 protruding from the lower surface of the circuit board 100 are inserted into the terminals on the lower surface of the circuit board 100. It is fixed by soldering or the like to a terminal mounting pattern (not shown) provided around the holes 101 and 101. Thereby, the attachment of the fixed resistor 1 to the circuit board 100 is completed. The fixed resistor 1 attached to the circuit board 100 has a large area of the case 10 facing the circuit board 100 side, so that the height dimension of the mounted fixed resistor 1 from the circuit board 100 can be reduced and fixed. The height of the circuit board 100 on which the resistor 1 is mounted can be reduced, and the mounting state is stabilized.

  As described above, according to the fixed resistor 1, since the plate resistor element 50 is inserted from the insertion port 13 provided on the outer peripheral side wall of the case 10, a small terminal insertion hole is provided in the case 10 to provide a terminal 80. Therefore, the plate resistor 50 can be easily inserted into the element housing 11 and the fixed resistor 1 can be easily assembled.

  Further, since the wall on the substrate facing surface 17 side of the case 10 is interposed between the terminal 80 projecting from the substrate facing surface 17 of the case 10 and the plate resistance element 50, the pulling strength of the projecting terminal 80 can be increased. .

  By the way, in the case of the fixed resistor described in the above-mentioned Patent Document 2, a filling material is filled in a storage portion having a wide opening provided on the bottom surface side of the case. Then, the surface of the filled material is pressed with a pressing member to flatten the surface, but since the pressing area is wide, the pressing force per unit area cannot be increased and it is difficult to make it flat. It was. On the other hand, in the case of the present embodiment, as described above, when the fixed resistor 1 is manufactured, as shown in FIG. 3, the insertion port 13 provided on the outer peripheral side wall having a small area of the case 10 faces upward. Since the filling material 90 is filled from the insertion port 13, the area of the filling material pressed by the pressing member with a pressing member is flat. For this reason, the pressing force per unit area of the surface of the filler 90 can be increased, and the surface can be easily planarized.

  Further, when the fixed resistor 1 is manufactured, as shown in FIG. 3, the fixed resistor 1 is installed so that the insertion port 13 of the case 10 faces upward, and the filling material 90 is filled in such a standing state. The (filler filling step) is the same as the filling method of the filler in the fixed resistor of the type standing on the circuit board shown in Patent Document 1. Therefore, the fixed resistor manufacturing equipment according to the present invention and the fixed resistor manufacturing equipment of the type that is installed on the circuit board can be the same equipment. Cost can be reduced.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, although the number of terminals is two in the above example, other various numbers may be used. In the above example, an example of the plate resistance element used in the present invention is shown. However, a plate resistance element having another structure may be used, and a resistance element other than the plate resistance element may be used. The fixed resistor according to the present invention may be used as a thermal fuse, a heater, or the like. In this case, a resistance element for a thermal fuse or a heater is used as the resistance element. It goes without saying that the shape and structure of each part such as the case, the terminal positioning part, and the guide / positioning protrusion can be variously changed, and the terminal positioning part and the guide / positioning protrusion may be omitted in some cases.

DESCRIPTION OF SYMBOLS 1 Fixed resistor 10 Case 11 Element accommodating part 13 Insertion port 17 Board | substrate opposing surface 19 Side | side of board | substrate opposing surface side 21 Terminal positioning part 23 Guide and positioning protrusion 50 Plate resistance element (resistance element)
80 Terminal 90 Filler 100 Circuit board

Claims (3)

In the fixed resistor which is placed on the circuit board and protrudes the terminal toward the board facing surface side which is the face facing the circuit board,
A resistance element to which the terminal is attached;
A case having an element storage portion for storing the resistance element;
A filler filled in the element storage portion of the case;
Comprising
The resistance element is inserted from an insertion port provided in an outer peripheral side wall adjacent to the substrate facing surface of the case,
And the terminal is bent at a portion protruding from the resistance element so that the terminal protrudes toward the substrate facing surface side of the case ,
Furthermore, when the fixed resistor is projected from the upper surface side, the terminal is within the projected area of the case . In the fixed resistor which is placed on the circuit board and protrudes the terminal toward the board facing surface side which is the face facing the circuit board,
A resistance element to which the terminal is attached;
A case having an element storage portion for storing the resistance element;
A filler filled in the element storage portion of the case;
Comprising
The resistance element is inserted from an insertion port provided in an outer peripheral side wall adjacent to the substrate facing surface of the case,
And the terminal is bent at a portion protruding from the resistance element so that the terminal protrudes toward the substrate facing surface side of the case,
Furthermore , the fixed resistor is characterized in that the side on the substrate facing surface side among the sides surrounding the insertion opening of the case is formed to be lower in height than the other sides. The fixed resistor according to claim 1 or 2 ,
A fixed portion characterized in that a leg portion is provided on the board-facing surface of the case to form a gap for air flow between the fixed resistor and the circuit board when the fixed resistor is placed on the circuit board. Resistor.

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