JP2018081971A - Press-fit terminal and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press-fit terminal capable of electrically detecting individual buckling irrespective of external appearance.SOLUTION: A press-fit terminal 20 (connector lead) is electrically connected to a target terminal 11 (through hole) to be connected. The press-fit terminal includes: a deformable portion 31 which first deforms by being brought into contact with the target terminal at a time of press-fitting; an energized portion 32 connected to the deformable portion in the press-fitting direction and in electrical contact with the target terminal; and a coating portion 33 covering the surface of the deformable portion in a film shape. The contact resistance between the coating portion and the target terminal has a resistance value larger than the contact resistance between the energized portion and the target terminal.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a press-fit terminal and an electronic device using the press-fit terminal.

  The press-fit terminal joins the two terminals by press-fit when connecting the two terminals. An example of the press-fit terminal is a press-fit terminal. The press-fit terminal is a terminal that is inserted into a through hole formed in the circuit board to ensure electrical connection. The press-fit terminal has a portion whose width is larger than the diameter of the through hole, and this portion is fixed by being elastically deformed by insertion into the through hole and urging the wall surface of the through hole. Realize continuity. That is, the press-fit terminal is press-fitted into the through-hole to realize the fixing and conduction between the terminal and the circuit board.

  By the way, a test for determining whether or not the press-fit terminal is normally inserted into the circuit board is generally performed. At the time of press-fitting the terminal, for example, a load for press-fitting increases due to a shift in the press-fitting position or the insertion angle, and the terminal may buckle. For example, when buckling occurs in a press-fit terminal, a defect can be found because the terminal does not penetrate the through hole and the tip of the terminal does not protrude to the back side of the circuit board. Such an inspection is an inspection based on the appearance. However, there is a case where the circuit board cannot be visually recognized from the outside due to the recent demand for downsizing of electronic devices, and a situation in which buckling cannot be found by the appearance inspection is being developed.

  On the other hand, the connector press-fitting machine described in Patent Document 1 detects the occurrence of buckling by detecting the press-fit load as an electrical signal. Specifically, it is determined that a defect has occurred when the press-fit load is larger than a prescribed reference value.

JP-A-8-330792

  However, in the connector press-fitting machine described in Patent Document 1, in order to detect the press-fitting load that occurs comprehensively for all the pins of the connector, for example, some of the pins are buckled. However, there is a possibility that the reference value is satisfied and a failure determination is not made.

  In addition, in order to identify individual press-fit loads, there is a description to determine by providing a member that deforms according to the press-fit load on the pressure-receiving surface of the terminal. If it is not visible, it cannot be adopted.

  In view of the above problems, an object of the present invention is to provide a press-fit terminal capable of electrically detecting individual buckling regardless of the appearance, and an electronic device using the press-fit terminal.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

  In order to achieve the above object, the present invention is a press-fit terminal that is electrically connected to a target terminal (11a, 46, 56) to be connected, and first contacts and deforms at the time of press-fit. Deformation part (31, 41, 51), current-carrying part (32, 42, 52) connected to the deformation part in the press-fitting direction and in electrical contact with the target terminal, and coating part covering the surface of the deformation part in a film form (33, 43, 53), and the contact resistance between the coating portion and the target terminal is larger than the contact resistance between the energization portion and the target terminal.

  When the press-fit terminal is buckled, the deformed portion and the target terminal come into contact with each other without contacting the current-carrying portion and the target terminal in the press-fit terminal as in normal operation. If the said structure is employ | adopted, since resistance value is detected higher than the conduction | electrical_connection resistance of the object terminal and press-fit terminal in normal time, individual buckling can be electrically detected. For this purpose, it is only necessary to perform an inspection by energization, and therefore, it can be performed with the same equipment as the conventional electrical inspection, and it is not necessary to provide a new inspection equipment.

It is sectional drawing which shows schematic structure of the electronic device concerning 1st Embodiment, and a press-fit terminal. It is sectional drawing which shows the structure before press-fit of a press-fit terminal. It is sectional drawing which shows the structure after the press-fit of a press-fit terminal. It is sectional drawing which shows the structure at the time of buckling generation | occurrence | production of a press-fit terminal. It is sectional drawing which shows schematic structure of the electronic device and press-fit terminal concerning a modification. It is sectional drawing which shows schematic structure of the electronic device and press-fit terminal concerning 2nd Embodiment. It is sectional drawing which shows schematic structure of the electronic device and press-fit terminal concerning 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same or equivalent parts.

(First embodiment)
First, a schematic configuration of the press-fit terminal and the electronic device according to the present embodiment will be described with reference to FIG.

  The press-fit terminal in the present embodiment is, for example, a press-fit terminal having a needle eye shape. This terminal mediates an electrical connection between a circuit board constituting the engine control electronic device and an external device, for example. The needle eye-shaped press-fit terminal is press-fitted into a through hole provided in the circuit board to establish the connection.

  As shown in FIG. 1, the electronic device 100 includes a circuit board 10 and connector leads 20.

  The circuit board 10 is a printed board having a plurality of through holes 11. An element 12 such as a resistor, a capacitor, or an IC chip is mounted on one surface of the circuit board 10. The circuit board 10 is supported by the base member 14 via the adhesive 13 on the surface opposite to the mounting surface of the element 12. The through hole 11 penetrates from the back surface where the adhesive 13 is not in contact with the mounting surface in the circuit board 10, and a connector lead 20 described later is inserted into the through hole 11. In addition, although the base member 14 in this embodiment is metal, you may be comprised with resin.

  The connector lead 20 has a press-fit terminal 30 at its tip, as shown in the AA cross section in FIG. The connector lead 20 is connected with a press-fit terminal 30 at the tip thereof being press-fitted into the through-hole 11, and the other end is connected to an external device (not shown). That is, the connector lead 20 mediates between the circuit board 10 and the external device. The connector lead 20 is fixed in the connector housing 21 by insert molding or outsert molding. The other end of the connector lead 20 that does not form the press-fit terminal 30 protrudes into a socket portion 21a formed in the connector housing 21, and a plug (not shown) is connected to the socket portion 21a.

  The tip of the connector lead 20 where the press-fit terminal 30 is formed protrudes from the connector housing 21 toward the circuit board 10. The press-fit terminals 30 are arranged corresponding to the positions where the through holes 11 are formed when the mounting surface is viewed from the front. The press-fit of the press-fit terminal 30 into the through hole 11 is realized by the connector lead 20 being pushed toward the circuit board 10 integrally with the connector housing 21. Simultaneously with the press-fitting of the press-fit terminal 30 into the through hole 11, the connector housing 21 contacts the base member 14 to form an internal space, and the circuit board 10 is housed and protected in the internal space formed by the connector housing 21 and the base member 14. Is done.

  The structure around the press-fit terminal 30 and the through-hole 11 to be connected will be described in detail with reference to FIGS. 2 is a cross-sectional view showing a state before the press-fit terminal 30 is press-fitted, and FIG. 3 is a cross-sectional view showing a state after the press-fit terminal 30 is press-fitted.

  As shown in FIG. 2, the inner wall of the through hole 11 in the circuit board 10 is covered with a conductor 11a. The conductor 11a is electrically connected to a wiring (not shown) or the like, and is connected to the press-fit terminal 30 press-fitted into the through hole 11 and the element 12 at the end of the wiring. That is, the conductor 11a corresponds to a target terminal that is a connection target described in the claims. The mounting surface of the circuit board 10 and the back surface thereof are protected by a resist 15.

  The press-fit terminal 30 in the present embodiment is a needle-eye press-fit terminal.

  The press-fit terminal 30 is a portion of the tip end side which is inserted first when press-fitting into the through-hole 11, a portion whose width is smaller than the inner diameter of the through-hole 11, and a conductor on the inner wall of the through-hole 11 first. And a deforming portion 31 including a portion that deforms in contact with 11a. As shown in FIG. 3, the deforming portion 31 is a portion that is located on the distal end side of the press-fit terminal 30, and a portion thereof is deformed in contact with the conductor 11 a constituting the through hole 11.

  The deformed portion 31 is substantially V-shaped in the front cross section, and the acute angle portion advances in the press-fitting direction and is inserted into the through hole 11. When the deformed portion 31 advances and reaches a portion wider than the inner diameter of the through hole 11, the deformed portion 31 is urged by the inner wall of the through hole 11 to be deformed and a press-fitting load is generated. Further advance into the interior. The deformation direction of the deformation portion 31 due to the urging of the through hole 11 is the left-right direction on the paper surface when referring to the front sectional view.

  Further, the press-fit terminal 30 has a current-carrying portion 32 that is connected to the deformable portion 31 in the press-fit direction (insertion direction) of the press-fit terminal 30. The energizing part 32 and the deforming part 31 are formed continuously and integrally. The energizing portions 32 are respectively connected to the two leg portions of the deformable portion 31 opened in a V-shape, and in a state before the press-fit terminal 30 is press-fitted into the through-hole 11, each other than the inner diameter of the through-hole 11. It is in a wide open state.

  As shown in FIG. 3, the energization part 32 after press-fitting is pressed into contact with the conductor 11 a constituting the through hole 11. In the state where the connector lead 20 and the circuit board 10 are connected as shown in FIG. 1, the press-fit terminal 30 is in the state shown in FIG. That is, the current-carrying portion 32 is in contact with the conductor 11a and is electrically connected.

  It is preferable that the deformation | transformation part 31 and the electricity supply part 32 are comprised with the material which has the spring property and electroconductivity which concern on a deformation | transformation, for example, can employ | adopt phosphor bronze, for example.

  Further, the press-fit terminal 30 has a coating portion 33 that covers the deformation portion 31 in a film shape. The coating part 33 in this embodiment is formed so that the deformation | transformation part 31 may be covered over the whole surface. The coating portion 32 is made of a material having a higher electrical resistivity than the deformable portion 31 and the energizing portion 32, and has a higher contact resistance when contacting the conductor 11a than when the coating portion 33 is not formed. ing.

  Any material can be used for the coating portion 33 as long as the contact resistance with the conductor 11a is larger than that of the energization portion 32. In other words, in addition to an insulator such as a resin or a fibrous material, metal plating having a higher electrical resistivity than the energizing portion 32 can be employed for the coating portion 33. Specifically, for resins, natural resins such as shellac and rosin, synthetic resins such as polyethylene, vinyl chloride, polystyrene, polyester, phenol, melamine, epoxy, and silicone, natural rubber, butyl rubber, ethylene propylene rubber, and silicone A rubber-based material such as rubber, a coil varnish produced by dissolving the above resin in a solvent, or an enamel varnish can be employed. Moreover, if it is metal plating, Ni plating, Al plating, Cr plating, Cu oxide plating, etc. are employable. In addition, when employ | adopting metal plating, it is preferable that it is passive. Furthermore, organic fiber materials such as paper, cotton yarn, silk and polyester, and nylon may be employed.

  Next, with reference to FIG. 3 and FIG. 4, the effect by employ | adopting the press-fit terminal 30 and the electronic device 100 which concern on this embodiment is demonstrated.

  The coating portion 33 is not covered on the surface of the energization portion 32. Therefore, when the press-fit terminal 30 is normally press-fitted into the through-hole 11 without buckling, the current-carrying portion 32 directly contacts the conductor 11a as shown in FIG. Can be ensured.

  By the way, when the buckling occurs in the press-fit terminal 30, the connector lead 20 is bent as shown in FIG. Although the bending direction depends on the bending moment of the connector lead 20, it is known that the frequency of bending is high in the direction perpendicular to the deformation direction of the deforming portion 31 and the energizing portion 32. This direction is the depth direction of the paper surface of the front cross-sectional view shown in FIG. In addition, buckling mostly occurs when a press-fitting load begins to be applied after the deformed portion 31 comes into contact with the conductor 11a of the through hole 11, and buckling rarely occurs after press-fitting progresses.

  As described above, assuming that buckling has occurred at the time when the press-fit load is applied after the deformable portion 31 contacts the conductor 11a of the through hole 11, the connector lead 20 buckles as shown in FIG. At this time, only the coating portion 33 covering the deformable portion 31 contacts the conductor 11a.

  As described above, the contact resistance between the coating portion 33 and the conductor 11a as the target terminal has a higher resistance value than the contact resistance between the energization portion 32 and the conductor 11a. Therefore, for example, when a constant voltage is applied between the connector lead 20 and the conductor 11a, the current flowing between the connector lead 20 and the conductor 11a is normally in contact with the energizing portion 32 and the conductor 11a as shown in FIG. Compared to the case, the current value when buckling occurs as shown in FIG. Thus, the buckling of the single press-fit terminal 30 can be detected electrically.

  Usually, after the connector lead 20 and the circuit board 10 are connected, it is common to perform an electrical continuity test. However, the conventional method does not include the coating portion 33 provided in the press-fit terminal 30 of this embodiment. In the configuration, even if buckling occurs, conduction may be established, so that buckling cannot be found. On the other hand, if the press-fit terminal 30 and the electronic device 100 according to the present embodiment are employed, the occurrence of buckling can be detected based on the magnitude of the contact resistance. Further, this inspection can be performed with the same equipment as the normal continuity inspection, and it is not necessary to provide a new inspection equipment.

(Modification)
The press-fit terminal 30 in the first embodiment is an example in which the coating portion 33 is formed only on the surface of the deformable portion 31, but the coating portion 33 may be coated with at least the surface of the deforming portion 31, As long as it is a part excluding the energization part 32 in which electrical contact with the conductor 11a is essential, the film part 33 may be additionally formed.

  As shown in FIG. 5, the coating portion 33 may be formed over the entire surface of the connector lead 20 exposed from the connector housing 21 including the deformable portion 31 except the energizing portion 32 of the press-fit terminal 30.

  Depending on the form of buckling, the connector lead 20 on the opposite side of the deformable portion 31 with respect to the energizing portion 32 may come into contact with the conductor 11a. Since the coating portion 33 covers the portion excluding the energizing portion 32 as in this modification, the contact resistance can be increased even for such a form of buckling. Can be detected.

  Note that the connector lead 20 and thus the press-fit terminal 30 according to this modification have a larger covering area of the coating portion 33 than the press-fit terminal 30 described in the first embodiment. When realizing electrical detection of buckling at low cost, it is preferable to employ the press-fit terminal 30 and the electronic device 100 in the first embodiment.

(Second Embodiment)
In 1st Embodiment and its deformation | transformation part, although the press-fit terminal 30 demonstrated the example which is a press-fit terminal, a press-fit terminal is not limited to a press-fit terminal.

  As shown in FIG. 6, the press-fit terminal 40 in this embodiment is a so-called tuning fork terminal. The press-fit terminal 40 as a tuning fork terminal has a structure in which one end is fixed to the circuit board 10, the other end has a deformed portion 41 and a current-carrying portion 42, and a film portion 43 is formed on the surface of the deformed portion 41.

  This will be specifically described. As shown in FIG. 6, one end of the press-fit terminal 40 is inserted into the through hole 11 formed in the circuit board 10, and is electrically connected to the conductor 11 a through the solder 45. The press-fit terminal 40 is extended and bent at a substantially right angle on the other end side with respect to a portion on one end side inserted into the through hole 11. The portion bent substantially at a right angle is mounted on the circuit board 10 while being inserted into the resin housing 44 for the purpose of ensuring strength and stability.

  The tip portion extending along the mounting surface of the circuit board 10 is divided into two parts. The bifurcated portion has elasticity so that another member can be sandwiched in the thickness direction of the circuit board 10. For example, as shown in FIG. 6, an external terminal 46 extending from the outside of the circuit board 10 can be held. In the present embodiment, the external terminal 46 corresponds to a target terminal that is a connection target described in the claims.

  The press-fit terminal 40 has a deformed portion 41 as a portion that first contacts when the external terminal 46 is press-fitted, and an energization portion 42 that establishes electrical contact with the external terminal 46 after press-fit. The opposing distance between the two deformation portions 41 is smaller than the diameter of the external terminal 46. In addition, the opposing distance between the two energization portions 42 is smaller than the diameter of the external terminal 46. Thereby, when the external terminal 46 contacts the deformation | transformation part 41 at the time of press fit, a press fit load will be produced.

  The press-fit terminal 40 has a coating portion 43 on the surface of the deformable portion 41. As in the first embodiment, the coating portion 43 is made of a material having a higher electrical resistivity than the deformation portion 41 and the energization portion 42, and the coating portion 43 is not formed when contacting the external terminal 46. The contact resistance is larger than that in FIG.

  In the present embodiment, buckling can occur in the external terminal 46 as the target terminal. When the press-fit terminal 40 according to the present embodiment is employed, when buckling occurs in the external terminal 46 during press-fit, the external terminal 46 contacts only the coating portion 43 and does not contact the energizing portion 42. That is, as in the first embodiment, when buckling occurs, the contact resistance between the press-fit terminal 40 and the external terminal 46 is detected larger than when the press-fit is completed normally. Therefore, the buckling of the corresponding external terminal 46 can be electrically detected for each press-fit terminal 40.

(Third embodiment)
The press-fit terminal includes a press-fit terminal and a tuning fork terminal, as well as a press-fit terminal. As shown in FIG. 7, the press-fit terminal 50 in the present embodiment is press-fitted into a hole 56 a provided in the bus bar 56 to establish electrical connection and fixation. In the present embodiment, the bus bar 56, and thus the hole 56 a, corresponds to a target terminal to be connected, and the press-fit terminal 50 includes a deformable portion 51, a current-carrying portion 52, and a coating portion 53.

  This will be specifically described. As shown in FIG. 7, the press-fit terminal 50 has a bowl-like shape with the tip divided into two. At each of the bifurcated tips, a deformed portion 51 that first comes into contact with the bus bar 56 when the press-fit terminal 50 is inserted into a hole portion 56a described later, and a deformable portion 51 in the press-fit direction of the press-fit terminal 50 are connected. In addition, a current-carrying part 52 having a diameter larger than that of the hole part 56a and a film part 53 that covers the surface of the deformable part 51 are formed.

  A part of the bus bar 56 as the target terminal is inserted into the through hole 11 of the circuit board 10 and is electrically connected by the solder 55. In this embodiment, the bus bar 56 is connected and fixed to the two circuit boards 10, and two hole portions 56 a into which the press-fit terminals 50 are to be press-fitted are formed at substantially the center of the bus bar 56 that mediates the two circuit boards 10. ing. As shown in FIG. 7, a portion of the bus bar 56 that extends from the circuit board 10 and connects the two circuit boards 10, except for a portion near the hole 56 a, is inserted into the resin housing 54. Has been. The resin housing 54 is partially removed in the vicinity of the hole 56a, so that the hole 56a is exposed to the outside.

  When the press-fit terminal 50 is press-fitted, when the advancement proceeds to a portion having a diameter larger than the hole portion 56a in the deformable portion 51, the deformable portion 51 comes into contact with the hole portion 56a. This causes a press-fit load. Then, by further advancing, the inner wall surface of the hole 56a and the energizing portion 52 come into contact with each other to establish an electrical connection.

  The press-fit terminal 50 has a coating portion 53 on the surface of the deformable portion 51. The film part 53 is made of a material having a higher electrical resistivity than the deformed part 51 and the energization part 52, as in the first and second embodiments, and the film part 53 is formed upon contact with the bus bar 56. Compared with the case where it is not carried out, it is in the state where contact resistance is large.

  In the present embodiment, buckling can occur in the press-fit terminal 50. When the press-fit terminal 50 according to the present embodiment is employed, when the press-fit terminal 50 is buckled during press-fit, the inner wall of the hole portion 56a contacts only the coating portion 53 and does not contact the energizing portion 52. That is, as in the first embodiment, when buckling occurs, the contact resistance between the press-fit terminal 50 and the bus bar 56 is detected larger than when the press-fit is completed normally. Therefore, buckling can be electrically detected for each press-fit terminal 50.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The press-fit terminal method is not limited to the press-fit method, tuning fork method, and press-contact method described in each embodiment.

  Moreover, the material which comprises the film parts 33, 43, and 53 is not limited to the illustrated material, If arbitrary contact resistance with an object terminal is larger than a corresponding electricity supply part, arbitrary materials can be used.

  Further, in each of the above-described embodiments, an example in which a constant voltage is applied and a current value is detected is shown as a buckling inspection method, but the present invention is not limited to this. For example, the voltage value generated at the press-fit terminal by applying a constant current may be detected, or the contact resistance may be directly detected. Further, if the appearance inspection is performed together with the electrical inspection in an environment where the appearance inspection is possible, the occurrence of buckling can be detected more reliably.

DESCRIPTION OF SYMBOLS 10 ... Circuit board, 11 ... Through hole, 20 ... Connector lead, 30 ... Press-fit terminal (press fit terminal), 31 ... Deformation part, 32 ... Current supply part, 33 ... Film part

Claims (7)

A press-fit terminal electrically connected to a target terminal (11a, 46, 56) to be connected;
Deformation portions (31, 41, 51) that first deform upon contact with the target terminal during press-fitting,
Current-carrying parts (32, 42, 52) connected to the deforming part in the press-fitting direction and in electrical contact with the target terminal
A coating part (33, 43, 53) for covering the surface of the deformation part in a film form,
The contact resistance between the coating portion and the target terminal is a press-fit terminal having a larger resistance value than the contact resistance between the energization portion and the target terminal.   The press-fit terminal according to claim 1, wherein the coating portion is an insulator.   The press-fit terminal according to claim 2, wherein the insulator is a resin.   The press-fit terminal according to claim 1, wherein the coating portion is a plating layer.   The press-fit terminal according to claim 4, wherein the plating layer is passive.   The press-fit terminal according to any one of claims 1 to 5, wherein the deformable portion and the energization portion have a needle eye shape. The press-fit terminal (30, 40, 50) according to any one of claims 1 to 6,
An electronic device comprising: a circuit board (10) to which the press-fit terminal is electrically connected.

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