JP2019211464A - Current sensor - Google Patents

Abstract

To provide a current sensor with which it is possible to further improve the reliability of current detection.SOLUTION: A current sensor 1 includes a housing 100 equipped with a bus bar, the housing 100 equipped with a bus bar comprising a housing 110 formed with an insulating resin material and a first bus bar 120 and a second bus bar 130 inserted into the housing 110. Furthermore, a recess 116 is formed in the housing 110, and a first exposure part 122c of the first bus bar 120 and a second exposure part 133c of the second bus bar 130 are exposed in this recess 116. A shunt resistor 200, while being accommodated inside of the recess 116, electrically connects the first exposure part 122c and the second exposure part 133c together.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a current sensor.

  In recent years, the types and number of electrical components for automobiles have increased rapidly, and the consumption of in-vehicle batteries has become increasingly severe. For this reason, it has been proposed to attach a current sensor to a battery post formed in the battery. In general, by attaching a current sensor to the battery post, the remaining amount of the battery is monitored and the alternator (generator) is controlled to improve fuel consumption, or the battery is based on the output of the current sensor. The degree of wear (deterioration) of the product is confirmed. As described above, in recent years when the in-vehicle battery is increasingly consumed, there is a demand for monitoring the remaining capacity of the battery for charge / discharge control. In order to meet such demands, a method has been proposed in which a current sensor is attached to the battery post and the degree of battery consumption is detected based on the magnitude of the current detected by the current sensor.

  For this type of current sensor, the current value is calculated using Ohm's law (current = voltage drop / resistance value) from the voltage drop when the current is passed through the shunt resistor and the resistance value of the shunt resistor. A so-called shunt type current sensor is generally known.

  As such a shunt-type current sensor, the one disclosed in Patent Document 1 is known. In Patent Document 1, a bus bar (connection region) connected to the pole of an electrical current supply device, a bus bar (connection region) connected to an electrical consumer, and two bus bars are electrically connected. A current sensor comprising a shunt resistor (measuring section) is disclosed.

  In this patent document 1, the bus bar with shunt resistance is formed by welding each joint portion between each bus bar and the shunt resistance, and the bus bar with shunt resistance is insert-molded in the housing. At this time, the bus bar with the shunt resistor is insert-molded in the housing so that the coupling portion between the shunt resistor and the shunt resistor in each bus bar is embedded in the housing.

Special table 2008-514941 gazette

  However, in the above conventional technique, after the bus bar with shunt resistance is formed, the bus bar with shunt resistance is insert-molded into the housing. A bus bar with a shunt resistor is insert-molded in the housing, so that the shunt resistor and the joint portion of each bus bar with the shunt resistor are embedded in the housing.

  For this reason, the bus bar with shunt resistance is deformed by the pressure of the resin material applied to the bus bar with shunt resistance during insert molding, the force applied to the bus bar with shunt resistance due to thermal expansion and contraction, vibration, etc. of the current sensor. May end up. As described above, when the bus bar with the shunt resistor is deformed, there is a possibility that the current cannot be correctly detected because the shunt resistor and the bus bar are not electrically connected.

  Further, in the above-described conventional technology, friction is generated between the bus bar with the shunt resistor and the housing when the current sensor is thermally expanded / contracted or vibrated, and static electricity may be generated by the friction. When static electricity is generated by friction generated between the bus bar with the shunt resistor and the housing, the static electricity may be noise and affect current detection by the current sensor.

  As described above, in the conventional technique, it is difficult to improve the reliability of current detection by the current sensor.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a current sensor that can further improve the reliability of current detection.

  The current sensor according to the present invention includes a housing formed of an insulating resin material, a first bus bar that is inserted so as to be partially embedded in the housing, and attached to a battery post, and the first bus bar is spaced apart from the first bus bar. A housing with a bus bar having a second bus bar inserted into the housing so as to be partially embedded in the disposed state and connected to a wire harness, and electrically connecting the first bus bar and the second bus bar A shunt resistor connected to the housing, wherein the housing is formed with a recess in which the first exposed portion of the first bus bar is exposed and the second exposed portion of the second bus bar is exposed. A resistor electrically connects the first exposed portion and the second exposed portion while being accommodated in the recess.

  Note that a circuit board to which a potential difference between both ends of the shunt resistor is input may be further provided, and the circuit board may be disposed in the recess.

  Further, a pair of output terminals connected to the circuit board and outputting a potential difference between both ends of the shunt resistor to the circuit board is further provided, and one output terminal of the pair of output terminals is integrated with the first bus bar. The other output terminal may be formed integrally with the second bus bar.

  Moreover, you may make it provide the sealing part sealed with the sealing material softer than the said resin material in the said recessed part.

  Furthermore, a concavo-convex portion is formed in a surface portion corresponding to the concave portion of the surface exposed to the outside of the housing, and the concavo-convex portion is formed in the interval direction between the first exposed portion and the second exposed portion in the concave portion. You may make it comprise the some groove | channel extended along a space | interval in the direction orthogonal to the said space | interval direction.

  The dimension of the shunt resistor in the interval direction may be longer than the dimension in the direction orthogonal to the interval direction.

  ADVANTAGE OF THE INVENTION According to this invention, the current sensor which can improve the reliability of an electric current detection more can be provided.

It is a perspective view which shows typically the battery with which the current sensor concerning one Embodiment is attached. It is a perspective view showing typically the state where the current sensor concerning one embodiment was equipped in the battery post. It is a perspective view showing the current sensor concerning one embodiment typically. 1 is an exploded perspective view schematically showing a current sensor according to an embodiment. It is a figure which shows an example of the manufacturing method of the current sensor concerning one Embodiment, Comprising: It is a perspective view which shows typically the state which has arrange | positioned insert components in the predetermined position. It is a figure which shows an example of the manufacturing method of the current sensor concerning one Embodiment, Comprising: It is a figure which shows typically the state which formed the housing with a bus-bar. It is a figure which shows an example of the manufacturing method of the current sensor concerning one Embodiment, Comprising: It is a figure which shows typically the state which has arrange | positioned shunt resistance to the housing with a bus-bar. It is a perspective view explaining the state in which the 1st bus bar and the 2nd bus bar are electrically connected by shunt resistance. It is sectional drawing which shows typically the state which has arrange | positioned the circuit board in the recessed part of the current sensor concerning one Embodiment. It is sectional drawing which shows typically the state which provided the sealing part in the recessed part of the current sensor concerning one Embodiment. It is a perspective view which shows the uneven | corrugated | grooved part formed in the thermal radiation part of the housing exposed on the surface of the sensor main-body part of FIG. It is the II sectional view taken on the line of FIG. The distribution of the stress caused by the temperature change in the shunt resistance connecting the first bus bar and the second bus bar exposed in the recess of the housing is shown. (A) shows the flow direction of the resin material in the portion forming the recess of the housing. FIG. 6B is a distribution diagram when the direction of the first bus bar and the second bus bar is aligned with each other, and FIG. 5B is a diagram in which the flow direction of the resin material in the portion forming the recess of the housing is orthogonal to the direction of the interval between the first bus bar and the second bus bar It is a distribution map at the time of making it a direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a current sensor having a function as a battery terminal attached to a battery will be exemplified.

  The current sensor 1 according to the present embodiment is attached to a battery 40 as shown in FIG. 1 to detect the charge / discharge current of the battery 40, and the remaining capacity and consumption of the battery 40 depending on the detected charge / discharge current. The degree is detected.

  Examples of the battery 40 include an in-vehicle battery that is disposed in an engine room of a vehicle and supplies electric power to an electrical component (vehicle-mounted component) mounted on the vehicle.

  In the present embodiment, as shown in FIG. 1, the battery 40 has a shape in which a part of a rectangular parallelepiped is cut out. Specifically, two corners adjacent to each other in the upper part of the rectangular parallelepiped are stepped so as to be one step lower than other portions. A substantially rod-shaped battery post 41 made of lead electrodes is formed so as to protrude upward from each of the lower surfaces (terminal mounting surfaces) on the upper surface of the battery 40. The battery post 41 projecting from one (right side in FIG. 1) is a positive battery post and the battery post 41 projecting from the other (left side) terminal mounting surface. 41 is a battery post on the negative electrode side.

  Thus, in this embodiment, the battery 40 in which the wall surface is formed beside the pair of battery posts (the positive side battery post 41 and the negative side battery post 41) is illustrated. However, the shape of the battery is not limited to the shape described above. For example, the battery may have a shape in which a pair of battery posts protrude from the upper surface of a substantially rectangular parallelepiped battery.

  The current sensor 1 according to this embodiment is attached to the battery post 41.

  As shown in FIGS. 2 and 3, the current sensor 1 connects the sensor unit 10 that detects the charge / discharge current of the battery 40, the battery terminal unit 20 attached to the battery post 41, and the wire harness 60. And a connection unit 30.

  Note that FIG. 3 is a diagram in which the current sensor 1 illustrated in FIG. 2 is turned upside down (upside down). That is, the upper side of the current sensor 1 shown in FIG. 2 is the lower side of the current sensor 1 shown in FIG. 4 to 10 are diagrams corresponding to FIG. That is, FIGS. 4 to 10 disclose diagrams in which the upper side of the current sensor 1 shown in FIG. 2 is the lower side.

  The sensor unit 10 shown in FIG. 2 includes a sensor main body 11 that detects the charging / discharging current of the battery 40, a connector part 12 that protrudes integrally to the side of the sensor main body 11 and fits with the mating connector, It has.

  In the following description, as shown in FIG. 2, a direction in which a mating connector (not shown) is fitted to the connector portion 12 may be referred to as a longitudinal direction X of the current sensor 1. Further, the direction orthogonal to the longitudinal direction X may be referred to as the width direction Y of the current sensor 1, and the standing direction of the battery post 41 attached to the battery terminal portion 20 may be referred to as the height direction Z of the current sensor 1.

  The sensor main body 11 includes a case that forms an outer shell, and a current sensor unit that is built in the case.

  Specifically, as shown in FIG. 4, the sensor body 11 includes an extended piece 122 and an output terminal 123 of the first bus bar 120, and an extended piece 133 and an output terminal 134 of the second bus bar 130. ing. Further, the sensor body 11 includes a body housing 111 that holds a part of the first bus bar 120 and a part of the second bus bar 130, and a shunt resistor 200 that electrically connects the first bus bar 120 and the second bus bar 130. And. Further, the sensor body 11 includes a circuit board 300 to which a potential difference between both ends of the shunt resistor 200 is input, and a sealing part 400 that seals the shunt resistor 200 and the circuit board 300. Details of each member constituting the sensor main body 11 will be described later.

  The shunt resistor 200 that electrically connects the first bus bar 120 and the second bus bar 130 is caused to function as a current sensor unit. That is, in this embodiment, the sensor main body 11 is formed by incorporating the shunt resistor 200 that functions as a current sensor in a case constituted by the main body housing 111 and the sealing portion 400.

  Further, as shown in FIG. 2, it is preferable to provide a heat radiating portion 11 a on the surface of the sensor main body 11. The heat radiation part 11a can be formed using a material having a relatively high thermal conductivity such as metal. As an example, it can be formed by arranging a metal plate formed into a corrugated shape so as to be exposed on the surface of the sensor body 11. In addition, a metal plate can be arrange | positioned by various methods, such as fitting by press injection, and integral molding by insert molding. Moreover, you may make it give the function as the thermal radiation part 11a by making the shape of main body housing 111 itself into a waveform.

  If such a heat radiating part 11a is provided, the surface area of the sensor main body part 11 can be increased, and the heat generated in the sensor main body part 11 can be discharged (discharged) to the outside more efficiently. That is, by providing the heat radiating part 11a, the heat radiating property (heat exhausting property) of the sensor main body part 11 can be further improved.

  The connector part 12 is formed in the cylindrical shape opened to one side, and the terminal metal fitting is incorporated in the inside. In the present embodiment, the connector portion 12 is formed by the connector terminal portion 151 of the connector pin 150 and the substantially cylindrical connector housing 113 formed so as to cover the connector terminal portion 151.

  The battery terminal portion 20 is formed on the first bus bar 120, and can be formed by, for example, bending or pressing the first bus bar 120. In the present embodiment, the battery terminal main body 121 of the first bus bar 120 serves as the battery terminal portion 20.

  As shown in FIG. 3, the battery terminal portion 20 includes an insertion portion 21 in which an insertion hole 21a into which the battery post 41 is inserted is formed, and a fixing bolt 51 shown in FIG. And a tightening portion 22 that is tightened with a nut 52.

  And in this embodiment, the internal diameter of the insertion hole 21a can be changed now by the fastening condition of the fastening part 22 of FIG. 3 by the volt | bolt 51 and the nut 52 which are shown in FIG.

  The battery terminal portion 20 can be attached to the battery post 41 as follows, for example. First, as shown in FIG. 2, the battery post 41 is inserted into the insertion hole 21a. And in the state which inserted the battery post 41 in the insertion hole 21a, the fastening part 22 is fastened with the volt | bolt 51 and the nut 52, and the diameter of the insertion hole 21a is reduced. Thus, the battery terminal portion 20 is mounted in a state of being electrically connected to the battery post 41.

  The connection part 30 includes a main body part 31 and a connection terminal part 32 provided so as to protrude from the main body part 31. The connection terminal portion 32 is electrically connected to the battery terminal portion 20. Specifically, the connection terminal portion 32 is electrically connected to the battery terminal portion 20 indirectly via the shunt resistor 200 of FIG. Thus, in the present embodiment, the configuration in which the wire harness 60 and the battery terminal unit 20 are electrically connected via the connection terminal unit 32 is illustrated. However, the wire harness 60 and the battery terminal unit 20 need only be configured to be electrically connected in a state where the wire harness 60 is connected to the connection unit 30 and are electrically connected via the connection terminal unit 32. There is no need to let them. For example, when the wire harness 60 and the battery terminal unit 20 are electrically connected and fastened (fixed) with the connection terminal unit 32 and a nut 72 described later, the connection between the connection terminal unit 32 and the battery terminal unit 20 It is possible to interpose an insulating resin. As described above, the connection terminal portion 32 may not be electrically connected to the battery terminal portion 20.

  In the present embodiment, the bolt mounting portion 131 of the second bus bar 130 shown in FIG. 4, the stud bolt 140 for mounting the wire harness, and the connection that holds the stud bolt 140 in a state of being electrically connected to the bolt mounting portion 131. A connecting portion 30 is formed with the side housing 112. Specifically, the main body portion 31 is formed by the bolt mounting portion 131, the head portion 141 of the stud bolt 140, and the connection side housing 112, and the shaft portion 142 of the stud bolt 140 serves as the connection terminal portion 32. The connection terminal portion 32 is formed so that the tip thereof faces upward when the battery terminal portion 20 is attached to the battery post 41.

  As shown in FIG. 2, the conductive portion 63 of the wire harness 60 is electrically connected to the connection terminal portion 32 of the connection portion 30.

  In the present embodiment, the conductive portion 63 is exposed at one end of the wire harness 60, and the conductive portion 63 and the wire harness terminal 61 are electrically connected by caulking and fixing the wire harness terminal 61 to the exposed conductive portion 63. Connected. Note that a load such as an electrical component mounted on the vehicle is electrically connected to the other end of the wire harness 60.

  In the present embodiment, the wire harness terminal 61 has a shape in which the distal end portion 62 is bent at a substantially right angle, and an insertion hole 62 a through which the connection terminal portion 32 is inserted is formed in the distal end portion 62. Yes. As described above, when the wire harness terminal 61 having a shape in which the distal end portion 62 is bent at a substantially right angle is used, when the wire harness terminal 61 is attached to the connection terminal portion 32, the wire harness 60 extends along the side surface of the battery 40. And space saving can be achieved.

  Then, when the distal end portion 62 is fastened with the nut 72 in a state where the connection terminal portion 32 is inserted into the insertion hole 62 a formed in the distal end portion 62, the wire harness terminal 61 is fixed to the connection portion 30, and the wire harness 60. Is electrically connected to the connection terminal portion 32.

  Further, as described above, the connection terminal portion 32 is electrically connected to the battery terminal portion 20. Therefore, if the wire harness terminal 61 is fixed to the connection terminal portion 32 while the battery terminal portion 20 is mounted on the battery post 41, a current flows between the load connected to the other end of the wire harness 60 and the battery 40. It becomes.

  At this time, the connection terminal portion 32 is electrically connected to the battery terminal portion 20 via the shunt resistor 200. Accordingly, the current flowing between the load and the battery 40 passes through the shunt resistor 200 that functions as a current sensor unit.

  If the current sensor 1 having such a configuration is used, the magnitude of the current flowing between the load and the battery 40 can be detected by the current sensor unit, so that the remaining capacity and the degree of wear of the battery 40 can be determined. become.

  The magnitude of the current flowing between the load and the battery 40 can be calculated using the voltage drop that occurs when a current is passed through the shunt resistor 200 and the resistance value of the shunt resistor 200.

  Here, in the present embodiment, the reliability of current detection by the current sensor 1 can be further improved.

  Specifically, the current sensor 1 includes a housing 100 with a bus bar shown in FIG.

  The housing with bus bar 100 includes a first bus bar 120 that is electrically connected to the battery post 41, and a second bus bar 130 that is electrically connected to the conductive portion 63 of the wire harness 60. The first bus bar 120 and the second bus bar 130 are held in the housing 110 formed of an insulating resin material, thereby forming the housing 100 with bus bars.

  In the present embodiment, the bus bar-equipped housing 100 is formed by insert molding with an insulating resin material in a state where the insert parts including the first bus bar 120 and the second bus bar 130 are arranged at predetermined positions. At this time, the insert part is held by the housing 110 in a state where a part thereof is embedded.

  In the present embodiment, the first bus bar 120, the second bus bar 130, the stud bolts 140 for attaching the wire harness, and the four connector pins 150 serve as insert parts that are inserted into the housing 110 during insert molding. .

  The first bus bar 120 has conductivity and rigidity, and can be obtained, for example, by bending or pressing a conductive metal plate having a predetermined shape.

  The first bus bar 120 includes a battery terminal main body 121 attached to the battery post 41 and an extending piece 122 connected to the battery terminal main body 121.

  The battery terminal main body 121 has a substantially U-shaped connecting part that connects the first opposing wall 124 and the second opposing wall 125 facing each other, and the end of the first opposing wall 124 and the end of the second opposing wall 125. 126. The first opposing wall 124 and the second opposing wall 125 can be formed, for example, by folding back a portion that becomes the connecting portion 126 of the conductive metal plate material so as to be substantially U-shaped. Further, in the present embodiment, an insertion hole 124 a is formed in a substantially central portion of the first opposing wall 124, and an insertion hole 125 a is formed in a substantially central portion of the second opposing wall 125. The insertion hole 124a and the insertion hole 125a overlap each other when viewed along the opposing direction of the first opposing wall 124 and the second opposing wall 125. When the battery terminal body 121 is attached to the battery post 41 of FIG. 2, the battery post 41 is inserted through the insertion hole 125a and the insertion hole 124a in this order. Thus, in this embodiment, the 1st opposing wall 124 and the 2nd opposing wall 125 are the insertion parts 21 of the battery terminal part 20 of FIG. 2, and the insertion hole 124a and the insertion hole 125a are the batteries of FIG. It is an insertion hole 21a into which the post 41 is inserted.

  In the present embodiment, a wide portion 124 b that is wider than the second opposing wall 125 is formed on the opposite side of the first opposing wall 124 to the connecting portion 126 side. On the other hand, side walls 125b extending toward the first opposing wall 124 are formed at both ends of the second opposing wall 125 in the width direction. Then, the ends of the pair of side wall portions 125b and 125b are abutted against the wide portion 124b of the first opposing wall 124, whereby the first opposing wall 124 and the second opposing wall 125 are separated by a predetermined distance (the height of the side wall portion 125b). (A), and are opposed to each other in a separated state.

  Further, in the present embodiment, claw portions 124c that are bent along the side wall portion 125b and the second opposite wall 125 are connected to both ends in the width direction of the first opposing wall 124, respectively. The portion 124c is hooked on the second opposing wall 125. By doing so, the second opposing wall 125 is prevented from opening with respect to the first opposing wall 124.

  Further, a notch 127 is formed at the center in the width direction of the battery terminal main body 121 from the insertion hole 124a in the first opposing wall 124 to the insertion hole 125a in the second opposing wall 125 through the substantially U-shaped connecting portion 126. Has been. That is, in this embodiment, the cut 127 is formed so as to communicate with the insertion hole 124a and the insertion hole 125a.

  And the connection part 126 is divided | segmented into the 1st connection part 126a and the 2nd connection part 126b by this notch 127. FIG. By forming such a cut 127, the insertion hole 124a and the insertion hole 125a are configured such that the inner diameter can be enlarged or reduced. That is, the insertion hole 124 a and the insertion hole 125 a are reduced in diameter by reducing the width of the cut 127.

  Moreover, the bolt 51 and the nut 52 for reducing the width | variety of the notch 127 are arrange | positioned at the 1st connection part 126a and the 2nd connection part 126b. Specifically, the shaft portion of the bolt 51 is inserted inside the first connection portion 126 a and the inside of the second connection portion 126 b, and the nut 52 is screwed into the shaft portion of the bolt 51. Then, by tightening the nut 52, the distance between the first connecting portion 126a and the second connecting portion 126b (the width of the notch 127) is shortened so that the insertion hole 124a and the insertion hole 125a are reduced in diameter. Thus, in this embodiment, the 1st connection part 126a and the 2nd connection part 126b are the clamping parts 22. FIG.

  The extending piece 122 is connected to the end of the first opposing wall 124 opposite to the connecting portion 126 side, and includes a flat portion 122b. The flat portion 122b is connected to the first opposing wall 124 (wide portion 124b) via the bent portion 122a, and is disposed in a state offset in the vertical direction with respect to the first opposing wall 124.

  Further, an output terminal 123 is integrally formed at the end of the flat portion 122b opposite to the connecting portion 126 side. The output terminal 123 is connected to the circuit board 300 and is used to output a potential difference between both ends of the shunt resistor 200 to the circuit board 300.

  Similarly to the first bus bar, the second bus bar 130 has conductivity and rigidity. For example, the second bus bar 130 can be obtained by bending or pressing a conductive metal plate having a predetermined shape.

  The second bus bar 130 includes a bolt attachment portion 131 to which the stud bolt 140 is attached, an extension piece 133 that is arranged with the bolt attachment portion 131 offset in the vertical direction, and the bolt attachment portion 131 and the extension piece 133. And a bent portion 132 that connects the two.

  The bolt mounting portion 131 has a substantially flat plate shape, and an insertion hole 131a through which the shaft portion 142 of the stud bolt 140 is inserted is formed in a substantially central portion. Further, an extended piece 131b having a shape bent substantially at a right angle is formed at the end of the bolt mounting portion 131. The extended piece 131b is a portion embedded in the resin material forming the housing 110, and is provided to increase the strength of the housing 110.

  The extended piece 133 has a substantially flat plate shape, and in the state in which the housing 100 with a bus bar is formed, the opposed portion 133a where the flat portion 122b and the end faces face each other is opposite to the bent portion 132 side of the opposed portion 133a. And an extended portion 133b that is connected to the end portion on the side. Note that the tip of the extended portion 133b is also a portion embedded in the resin material that forms the housing 110, and is provided to increase the strength of the housing 110.

  In addition, in the state where the housing 100 with bus bar is formed, an output terminal 134 is integrally formed at an end portion of the facing portion 133a on the flat portion 122b side. The output terminal 134 is connected to the circuit board 300 together with the output terminal 123, and is used to output a potential difference between both ends of the shunt resistor 200 to the circuit board 300.

  It is preferable that the surface of the first bus bar 120 and the surface of the second bus bar 130 be plated with tin. This facilitates soldering on the surface of the bus bar.

  In the present embodiment, the stud bolt 140 has conductivity, and is electrically connected to the wire harness terminal 61. That is, the stud bolt 140 is fixed in a state where it is electrically connected to the bolt mounting portion 131 of the second bus bar 130. Specifically, the shaft portion 142 of the stud bolt 140 is inserted into the insertion hole 131a of the bolt mounting portion 131, and the head 141 is brought into contact with the peripheral portion of the insertion hole 131a in the bolt mounting portion 131. By doing so, the stud bolt 140 is fixed in a state of being electrically connected to the bolt mounting portion 131.

  In addition, the wire harness terminal 61 should just be electrically connected with the 2nd bus-bar 130, when the front-end | tip part 62 is fastened (fixed) using the stud bolt 140 and the nut 72. FIG. That is, the wire harness terminal 61 need not be electrically connected to the second bus bar 130 via the stud bolt 140 or the nut 72. For example, an insulating portion such as a resin may be interposed between the wire harness terminal 61 and the nut 72 or between the second bus bar 130 and the stud bolt 140.

  The connector pin 150 is a member for electrically connecting the circuit board 300 to the mating connector, and has a shape obtained by bending a rod-shaped conductive member. Specifically, the connector pin 150 includes a connector terminal portion 151 that is conductively connected to the terminal fitting of the mating connector, a circuit board side terminal portion 152 that is conductively connected to the circuit board 300, and the connector terminal portion 151 and the circuit board. A connecting portion 153 that connects the side terminal portion 152. And in the state which formed the housing 100 with a bus bar, at least one part of the connection part 153 is embed | buried under the housing 110. FIG. That is, the connector pin 150 is held by the housing 110 so as to penetrate the housing 110.

  And as above-mentioned, such an insert component is hold | maintained at the housing 110 in the state embedded partially.

  In this embodiment, the housing 110 constitutes a main body housing 111 that constitutes a part of the outline of the sensor main body part 11, a connection-side housing 112 that constitutes a part of the connection part 30, and a part of the connector part 12. Connector housing 113.

  The main body housing 111 is formed to have a recess 116 at the center, and has a substantially square box shape. The main body housing 111 includes a back wall 115 located on the back side with respect to the opening 116a of the recess 116, and a peripheral wall 114 provided continuously over the entire outer periphery of the back wall 115 ( (See FIG. 6). A recess 116 is defined by the inner surface 114 a of the peripheral wall 114 and the inner surface 115 a of the back wall 115.

  Further, in the present embodiment, a stepped portion 111a having a substantially L shape between the inner surface 115a of the back wall 115 and the opening 116a in the main body housing 111 when the back wall 115 is viewed from the opening 116a side. Is formed. By forming such a stepped portion 111a, a part of the recess 116 is a recess having a deeper depth than other parts.

  Further, with the housing 100 with bus bar formed, a part of the flat part 122b of the first bus bar 120, a part of the facing part 133a of the second bus bar 130, the tips of the output terminals 123 and 134, and the circuit board side terminal part 152. The front end of each is exposed to the recess 116.

  Specifically, the main body housing 111 is formed so that a part of the flat part 122b and a part of the facing part 133a are exposed to a deep part in the recess 116. Therefore, in this embodiment, a part of the flat part 122b is the first exposed part 122c exposed to the concave part 116, and a part of the facing part 133a is the second exposed part 133c exposed to the concave part 116. .

  Further, the main body housing 111 is formed so that the tips of the output terminals 123 and 134 and the tip of the circuit board side terminal portion 152 protrude from the stepped portion 111a toward the opening 116a (exposed to a recess having a shallow depth). ing.

  Accordingly, the shunt resistor 200 is accommodated in a deep recess among the recesses 116, and the circuit board 300 is accommodated in a recess having a shallow depth.

  As described above, in the present embodiment, the recess defined by the inner surface 115 a of the back wall 115 of the recess 116 is the first recess 117 that houses the shunt resistor 200. And the recessed part defined by the level | step-difference part 111a among the recessed parts 116 becomes the 2nd recessed part 118 which accommodates the circuit board 300 (refer FIG. 10).

  In the present embodiment, as shown in FIGS. 4 and 10, a plurality of ribs 111 b are provided in the recess 116. The plurality of ribs 111b are provided to prevent peeling of the sealing portion 400 formed by injecting a sealing material into the recess 116 or to improve the adhesion by the sealing portion 400. is there. Further, a part of the plurality of ribs 111b is formed so as to protrude toward the opening 116a between the output terminal 123 and the output terminal 134 or between the adjacent circuit board side terminal portions 152. ing. As shown in FIG. 10, when the circuit board 300 is accommodated in the second recess 118, the circuit board 300 is placed on the rib 111b protruding toward the opening 116a.

  The connection-side housing 112 has a substantially rectangular parallelepiped shape, and includes a peripheral wall 112 a that is connected to the side of the main body housing 111 on one side. The connection-side housing 112 includes a fixing portion 112b that is formed inside the peripheral wall 112a and fixes the bolt attachment portion 131 and the stud bolt 140 in an electrically connected state. In the present embodiment, the bolt mounting portion 131 and the head 141 of the stud bolt 140 fixed to the bolt mounting portion 131 are embedded in the fixing portion 112b. The fixing portion 112b only needs to be fixed in a state where the bolt mounting portion 131 and the stud bolt 140 are electrically connected, and fixes the entire bolt mounting portion 131 and the entire head 141. It is not necessary to embed in the part 112b.

  The connector housing 113 has a substantially cylindrical shape and is connected to the main body housing 111. Specifically, the connector housing 113 is formed so as to protrude outward from a side adjacent to the side of the main body housing 111 where the connection side housing 112 is connected. As described above, in the present embodiment, the connection-side housing 112 and the connector housing 113 project from the main body housing 111 so as to extend in directions intersecting with each other.

  In this embodiment, the connector terminal portion 151 of the connector pin 150 is covered with the connector housing 113 in a state where the housing 100 with bus bar is formed. The connector housing 113 and the connector terminal portion 151 form a connector portion 12 that fits into the mating connector.

  The housing 100 with a bus bar having such a configuration can be formed as follows, for example.

  First, the insert parts including the first bus bar 120 and the second bus bar 130 are held by a mold or the like (not shown) and arranged so as to be in the state shown in FIG. That is, the first bus bar 120 and the second bus bar 130 are arranged so as to be completely separated from each other. Specifically, the first bus bar 120 and the second bus bar 130 are arranged so that the end surface of the flat portion 122b and the end surface of the facing portion 133a are opposed to each other. At this time, it is preferable that the surface of the flat portion 122b and the surface of the facing portion 133a are substantially the same plane.

  Further, the shaft portion 142 of the stud bolt 140 is inserted into the insertion hole 131 a formed in the bolt mounting portion 131 of the second bus bar 130, and the head 141 is brought into contact with the bolt mounting portion 131. At this time, the shaft portion 142 is inserted into the insertion hole 131a so as to protrude to the side opposite to the opening 116a side of the recess 116 formed in the main body housing 111.

  Then, the four connector pins 150 are arranged above the facing portion 133a (on the opening 116a side) in a state of being separated from the first bus bar 120, the second bus bar 130, and the stud bolt 140. At this time, the four connector pins 150 are arranged so that the connector terminal portion 151 faces sideward and the circuit board side terminal portion 152 faces upward (opening 116a side), and each of the four connector pins 150 is another connector pin 150. Are arranged in a separated state.

  Next, the insert 110 is insert-molded in a state where the insert parts are arranged as shown in FIG. 5 to form the housing 110 in which the insert parts are inserted. Specifically, the housing 110 into which insert parts are inserted is formed by injecting a molten insulating resin material into a cavity formed in a mold (not shown). As an insulating resin material forming the housing 110, for example, polyphenylene sulfide resin (PPS resin) having a melting point higher than that of solder can be used. Moreover, you may make it raise the intensity | strength of the housing 110 by mixing a glass filler etc. with an insulating resin material.

  In this way, the housing 100 with a bus bar shown in FIG. 6 is formed. The first bus bar 120 and the second bus bar 130 are inserted in a state where the first exposed portion 122c and the second exposed portion 133c are connected, and then the connected portion is cut to obtain the first exposed portion 122c. The second exposed portion 133c may be formed. By so doing, the flatness of the first exposed portion 122c and the second exposed portion 133c can be increased.

  Then, after forming the housing 100 with the bus bar, the first exposed portion 122c of the first bus bar 120 and the second exposed portion 133c of the second bus bar 130 while the shunt resistor 200 is accommodated in the first concave portion 117 (the concave portion 116). (See FIG. 7). By doing so, the first bus bar 120 and the second bus bar 130 inserted and held in the housing 110 in a state of being spaced apart from each other are electrically connected (see FIG. 8).

  The shunt resistor 200 is a resistor that has a relatively small change in resistance value due to a temperature change. Therefore, by using the shunt resistor 200, it is possible to obtain the current sensor 1 that is not easily affected by temperature changes.

  In the present embodiment, a surface mount type (chip shunt resistor) is used as the shunt resistor 200. As such a shunt resistor 200, a conventionally known shunt resistor can be used.

  Such a shunt resistor 200 is mounted on the first bus bar 120 and the second bus bar 130 by solder. Thus, if the surface mount type shunt resistor 200 is mounted using solder, it is not necessary to access the shunt resistor 200 from the back when connecting the shunt resistor 200 to the bus bar, and the shunt resistor 200 can be more easily attached to the bus bar. Can be connected. In addition, since the opening (the opening 116a of the recess 116) can be only on one side, the sealing material can be easily injected and the sealing part 400 can be formed more easily.

  Furthermore, in the present embodiment, the first recess 117 in which the shunt resistor 200 is accommodated is formed to be slightly larger than the shunt resistor 200. That is, the shunt resistor 200 is surrounded by the inner surface 114a that defines the first recess 117 in a state where the shunt resistor 200 is accommodated in the first recess 117. In this way, when the shunt resistor 200 is soldered to the first exposed portion 122c and the second exposed portion 133c, the solder is blocked by the inner surface 114a, and the soldering can be performed more reliably. Further, since the displacement of the shunt resistor 200 is suppressed by the inner surface 114a, an error due to the connection displacement of the shunt resistor 200 can be reduced.

  Then, after the shunt resistor 200 is mounted on the first exposed portion 122c and the second exposed portion 133c, the circuit board 300 is accommodated in the second recessed portion 118 (recessed portion 116).

  The circuit board 300 has a substantially square shape, and an amplifier circuit or the like that amplifies the voltage (potential difference) of the shunt resistor 200 input to the circuit board 300 is formed by mounting various electronic components. Note that illustration of electronic components mounted on the circuit board 300 is omitted. Further, the circuit board 300 is formed with an insertion hole 310 through which the tip of the circuit board side terminal portion 152 is inserted, and an insertion hole 320 through which the tips of the output terminals 123 and 134 are inserted.

  Therefore, the circuit board 300 is placed on the rib 111b in a state where the tip of the circuit board side terminal portion 152 is inserted into the insertion hole 310 and the tips of the output terminals 123 and 134 are inserted into the insertion holes 320, respectively. As a result, the second recess 118 is accommodated. At this time, it is preferable that the entire shunt resistor 200 is covered with the circuit board 300 (the entire shunt resistor 200 overlaps the circuit board 300 in the vertical direction). In this way, the shunt resistor 200 and the circuit board 300 can be accommodated in the recess 116 without enlarging the recess 116.

  Then, the circuit board side terminal portion 152 and the output terminals 123 and 134 are soldered (mounted) to the circuit board 300 in a state where the circuit board 300 is accommodated in the second recess 118.

  The mounting of the shunt resistor 200 and the mounting of the circuit board 300 (soldering of the circuit board side terminal portion 152 and the output terminals 123 and 134 to the circuit board 300) are performed at a time by, for example, reflow soldering. May be. At this time, electronic components can be mounted on the circuit board 300 at the same time.

  Thereafter, the sealing portion 400 is formed by filling the recess 116 with a sealing material softer than the resin material forming the housing 110. As such a sealing material, for example, an elastic and adhesive urethane resin can be used. The recess 116 in which the shunt resistor 200 and the circuit board 300 are accommodated is sealed with a sealing material so that the interface is adhered, and the waterproof / dustproof effect can be enhanced and the generation of static electricity can be suppressed. It becomes like this.

  In the present embodiment, when the current sensor 1 is mounted on the battery post 41, the recess 116 is formed so that the opening 116a opens downward. Therefore, when the current sensor 1 is attached to the battery post 41, the surface of the sealing portion 400 faces downward. Therefore, even if water enters the recess 116, the water can be drained without accumulating in the recess 116.

  And the current sensor 1 concerning this embodiment will be formed by forming the sealing part 400. FIG. In addition, the manufacturing method of the current sensor 1 mentioned above is an example, and it is also possible to manufacture the current sensor 1 by another method.

  As described above, the current sensor 1 according to the present embodiment includes the housing 100 with a bus bar. The housing with bus bar 100 includes a housing 110 formed of an insulating resin material, and a first bus bar 120 inserted so as to be partially embedded in the housing 110. Further, the bus bar-equipped housing 100 includes a second bus bar 130 that is disposed so as to be separated from the first bus bar 120 and is inserted so as to be partially embedded in the housing 110.

  Further, the current sensor 1 includes a shunt resistor 200 that electrically connects the first bus bar 120 and the second bus bar 130.

  In addition, the housing 110 is formed with a recess 116 in which the first exposed portion 122c of the first bus bar 120 is exposed and the second exposed portion 133c of the second bus bar 130 is exposed.

  The shunt resistor 200 electrically connects the first exposed portion 122c and the second exposed portion 133c while being accommodated in the recess 116.

  In this way, the shunt resistor 200 can be connected to the first bus bar 120 and the second bus bar 130 after the housing 100 with bus bars is formed by insert molding. Accordingly, the pressure of the resin material is not applied to the joint portion between the shunt resistor 200 and the bus bar (the first bus bar 120 or the second bus bar 130) as in the case of insert molding the bus bar with the shunt resistor.

  As a result, it is possible to suppress the deformation of the shunt resistor 200 or the joint between the shunt resistor 200 and the bus bar, and to suppress the electrical connection between the shunt resistor 200 and the bus bar. it can. That is, the shunt resistor 200 and the bus bar can be electrically connected more reliably.

  Further, the shunt resistor 200 is accommodated in the recess 116 formed in the housing 110. Therefore, it is possible to suppress the force generated in the housing 110 due to the thermal expansion / contraction of the housing 110 or the vibration of the current sensor 1 from being transmitted directly to the shunt resistor 200 or the junction between the shunt resistor 200 and the bus bar. As a result, the shunt resistor 200 and the bus bar can be more reliably electrically connected. In addition, since insert molding can be prevented in a state where the shunt resistor 200 is connected to the first bus bar 120 and the second bus bar 130, the molding pressure and the stress of thermal expansion and contraction applied during molding are affected by the shunt resistance. It can be prevented from being added to 200.

  Furthermore, it is possible to suppress the occurrence of friction between the housing 110 and the shunt resistor 200 when the housing 110 is thermally expanded or contracted or when the current sensor 1 vibrates. As a result, generation of static electricity is suppressed and noise of the current sensor 1 can be reduced. For example, when an elastic and adhesive resin is used as a sealing material for forming the sealing portion 400, the sealing portion 400 is in close contact with the shunt resistor 200 in a state of having elasticity. Therefore, the sealing portion 400 moves together with the shunt resistor 200 at the time of thermal expansion / contraction or vibration of the current sensor 1. As described above, the sealing unit 400 moves together with the shunt resistor 200, so that the generation of friction is suppressed, and the generation of static electricity due to the friction can be suppressed.

  Thus, according to the present embodiment, the current sensor 1 that can further improve the reliability of current detection can be obtained.

  Further, if the shunt resistor 200 is connected to the first bus bar 120 and the second bus bar 130 after the housing 100 with bus bars is formed by insert molding, the shunt resistor 200 is prevented from being deteriorated by insert molding. be able to. Further, if the shunt resistor 200 is mounted after insert molding the housing 100 with bus bar, the mounting shape of the shunt resistor 200 can be formed in advance in the housing 110, and the shunt resistor 200 can be mounted more easily. be able to.

  In the present embodiment, the current sensor 1 further includes a circuit board 300 to which a potential difference between both ends of the shunt resistor 200 is input. The circuit board 300 is disposed in the recess 116.

  By doing so, it is not necessary to separately form a recess for housing the shunt resistor 200 and a recess for housing the circuit board 300 in the housing 110, and the configuration can be simplified.

  In the present embodiment, the current sensor 1 further includes a pair of output terminals 123 and 134 that are connected to the circuit board 300 and output a potential difference between both ends of the shunt resistor 200 to the circuit board 300.

  One output terminal 123 of the pair of output terminals 123 and 134 is formed integrally with the first bus bar 120, and the other output terminal 134 is formed integrally with the second bus bar 130.

  Thus, by forming the output terminals 123 and 134 directly on the bus bar (the first bus bar 120 or the second bus bar 130), more accurate voltage data can be transmitted.

  In the present embodiment, the shunt resistor 200 is directly soldered to the bus bar (the first bus bar 120 or the second bus bar 130). Therefore, the cost can be reduced compared to the case where the shunt resistor 200 is mounted on the circuit board 300, and the current can be increased.

  In the present embodiment, a sealing portion 400 that is sealed with a sealing material softer than the resin material is provided in the recess 116.

  In this way, the waterproof / dustproof effect can be enhanced, and the generation of static electricity can be suppressed.

  By the way, when the housing 110 is thermally expanded and contracted due to a temperature change, the first bus bar 120 and the second bus bar 130 held by the housing 110 move. By this movement, the distance between the first exposed portion 122c of the first bus bar 120 and the second exposed portion 133c of the second bus bar 130 changes according to the coefficient of thermal expansion of the insulating resin material that is the material of the housing 110. .

  On the other hand, when a temperature change occurs in the shunt resistor 200 in which both ends are soldered to the first exposed portion 122c and the second exposed portion 133c, thermal expansion and contraction according to the thermal expansion coefficient of the metal material used for the shunt resistor 200 occurs. This occurs in the shunt resistor 200.

  Here, the thermal expansion coefficient differs between the resin material of the housing 110 and the metal material of the shunt resistor 200. For this reason, the housing 110 and the shunt resistor 200 are thermally expanded at different thermal expansion rates in the interval direction between the first exposed portion 122c of the first bus bar 120 and the second exposed portion 133c of the second bus bar 130 when the temperature changes. Shrink.

  As a result, the first exposed portion 122c and the second exposed portion 133c and the second exposed portion 133c are soldered to the shunt resistor 200 according to the difference in thermal expansion coefficient between the housing 110 and the shunt resistor 200. Stress in the direction of the distance from the exposed portion 133c is generated.

  By the way, when glass filler etc. are mixed with the resin material of the housing 110, the thermal expansion coefficient of the housing 110 becomes relatively low in the fiber direction of the glass filler mixed with the resin material, and in other directions. Relatively high. Therefore, the difference in thermal expansion coefficient between the housing 110 and the shunt resistor 200 is relatively small in the fiber direction of the glass filler in the resin material and relatively large in the other directions.

  For this reason, when the fiber direction of the glass filler in the resin material is aligned with the interval direction between the first exposed portion 122c and the second exposed portion 133c, the difference in thermal expansion coefficient between the housing 110 and the shunt resistor 200 in the interval direction. Becomes smaller. Then, the stress in the interval direction between the first exposed portion 122c and the second exposed portion 133c, which is generated at the soldered portion of the shunt resistor 200, is reduced. Incidentally, the fiber direction of the glass filler is the direction along the flow direction of the resin material in the mold (not shown) when the bus bar-equipped housing 100 is formed by insert molding.

  The thermal expansion coefficient of the housing 110 formed by insert molding is relatively small in the flow direction of the resin material at the time of insert molding, even if the resin material does not contain a glass filler. May be large.

  Therefore, in this embodiment, the flow direction of the resin material of the housing 110 is devised at the time of insert molding of the housing 100 with bus bars. Hereinafter, the flow direction of the resin material during insert molding will be described.

  First, as shown in FIG. 6, the first exposed portion 122 c of the first bus bar 120 and the second exposed portion 133 c of the second bus bar 130 are exposed in the recess 116 of the housing 110, and are formed on the inner surface 115 a of the back wall 115. Are arranged along. The back wall 115 of the recess 116 is in a front-to-back positional relationship with the sensor body 11 of FIG. 2 provided on the surface of the housing 110.

  As described at the beginning of the present embodiment, the corrugated heat dissipating portion 11a is exposed on the surface of the sensor main body 11 of FIG. The waveform of the heat radiating portion 11a can be configured by arranging a corrugated metal plate in a portion exposed on the surface of the sensor main body portion 11, and the shape of the main body housing 111 of the portion can also be configured as a waveform. .

  In either case, when the housing 100 with bus bars is formed by insert molding, a portion of the surface of the housing 110 that is exposed on the surface of the sensor main body 11 is exposed to the heat radiating portion 11a as shown in FIGS. It is necessary to form the concavo-convex portion 160 corresponding to the waveform.

  11 is a perspective view of the current sensor 1 showing the concavo-convex portion 160 formed on the heat radiating portion 11a of the housing 110 exposed on the surface of the sensor main body 11, and FIG.

  As shown in FIG. 11, the concavo-convex portion 160 has a plurality of straight grooves 161. Each groove 161 extends along the longitudinal direction X of the current sensor 1 and is arranged side by side at equal intervals in the width direction Y of the current sensor 1 (corresponding to a direction orthogonal to the interval direction in the claims). ing. And in this embodiment, each groove | channel 161 is extended in the longitudinal direction X of the current sensor 1, and the space | interval of the 1st exposed part 122c and the 2nd exposed part 133c exposed to the recessed part 116 of the housing 110 shown in FIG. Aligned in the same direction as direction W.

  For this reason, a portion of the mold (not shown) that uses the housing 100 with bus bars for insert molding, where the concave and convex portion 160 is formed on the surface of the housing 110, has a cross-section with an inverted shape of the cross-sectional shape of each groove 161 shown in FIG. A plurality of projecting pieces (not shown) are formed side by side. Therefore, as shown in FIG. 11, each groove 161 extends in the flow direction α when the resin material of the housing 110 filled in the cavity (not shown) of the mold flows through the formation portion of the uneven portion 160. The current sensor 1 is regulated in the longitudinal direction X.

  Note that a gate arrangement area 170 surrounded by a one-dot chain line in FIG. 11 indicates a range of positions of the filling gate of the resin material provided in the mold. Even if the position of the filling gate of the mold is offset in the width direction Y of the current sensor 1 with respect to the uneven portion 160 within the range of the gate arrangement area 170, the flow direction α of the resin material in the formation portion of the uneven portion 160 Remains unchanged in the longitudinal direction X of the current sensor 1.

  In addition, the resin material that flows in the portion forming the main body housing 111 around the concavo-convex portion 160 is also guided by the resin material that flows while the formation portion of the concavo-convex portion 160 is regulated by the groove 161, and thus the longitudinal direction of the current sensor 1. Flow to X. Therefore, the main body housing 111 of the housing 110 having the recess 116 in which the first exposed portion 122 c of the first bus bar 120 and the second exposed portion 133 c of the second bus bar 130 are exposed is along the longitudinal direction X of the current sensor 1. It is formed of a resin material that flows in the flow direction α.

  Here, the flow direction α of the resin material forming the recess 116 of the main body housing 111 in the mold, the first exposed portion 122c of the first bus bar 120 and the second exposed portion of the second bus bar 130 to which the shunt resistor 200 is connected. The relationship with the space | interval direction W (refer FIG. 6) of the part 133c is demonstrated.

  The thermal expansion coefficient of the recess 116 of the main body housing 111 formed by flowing the resin material in the mold is relatively low in the flow direction α of the resin material and relatively high in the direction orthogonal to the flow direction α. . Therefore, the difference in coefficient of thermal expansion between the recess 116 of the main body housing 111 and the shunt resistor 200 is relatively small in the flow direction α of the resin material and relatively large in the direction orthogonal to the flow direction α.

  Therefore, in this embodiment, the flow direction α of the resin material in the formation portion of the main body housing 111 having the recess 116 is defined as the interval direction W between the first exposed portion 122c and the second exposed portion 133c exposed to the recess 116 (FIG. 6). See). This interval direction W is the same direction as the longitudinal direction of the current sensor 1 in which the groove 161 extends.

  When the main body housing 111 having the recess 116 is formed of a resin material in which the flow direction α is aligned with the interval direction W between the first exposed portion 122c and the second exposed portion 133c, the coefficient of thermal expansion between the main body housing 111 and the shunt resistor 200 is formed. Is the smallest in the interval direction W described above.

  Therefore, the stress (shearing stress) in the interval direction W generated at the soldering locations on the first exposed portion 122c and the second exposed portion 133c of the shunt resistor 200 due to the difference in coefficient of thermal expansion when the temperature changes is shown in FIG. As shown in the distribution diagram of), both values are small to medium.

  For comparison, the flow direction α of the resin material in the formation portion of the body housing 111 having the recess 116 is aligned with the width direction Y of the current sensor 1 orthogonal to the longitudinal direction X of the current sensor 1 in which the groove 161 extends. Consider the case.

  When the main body housing 111 having the recess 116 is formed of a resin material in which the flow direction α is aligned with the width direction Y of the current sensor 1, the difference in thermal expansion coefficient between the main body housing 111 and the shunt resistor 200 is the width of the current sensor 1. It becomes the smallest in the direction Y. In other words, the difference in coefficient of thermal expansion between the main body housing 111 and the shunt resistor 200 is greatest in the interval direction W between the first exposed portion 122c and the second exposed portion 133c.

  Therefore, when the main body housing 111 and the shunt resistor 200 are thermally expanded and contracted due to a temperature change, there is a large difference in the amount of thermal expansion and contraction between the first exposed portion 122c and the second exposed portion 133c in the interval direction W. .

  Then, due to the difference in thermal expansion and contraction amount between the two, the stress (shear stress) in the interval direction W generated in the soldered portion of the shunt resistor 200 with respect to the first exposed portion 122c and the second exposed portion 133c is shown in FIG. As shown in the distribution diagram of FIG. If the stress (shear stress) generated at the soldering location of the shunt resistor 200 is large, the shunt resistor 200 is deformed and the current detection accuracy using the shunt resistor 200 is lowered, and the reliability of current detection cannot be maintained. End up.

  On the other hand, in this embodiment, the flow direction α of the resin material is aligned with the interval direction W between the first exposed portion 122c and the second exposed portion 133c, and the thermal expansion / contraction amount in the interval direction W due to the temperature change is set. A big difference is not made.

  For this reason, the stress (shear stress) in the interval direction W generated at the soldered portion of the shunt resistor 200 is suppressed to a small value as shown in FIG. In addition, the reliability of current detection can be further improved.

  4-7, in the current sensor 1 of this embodiment, the shunt resistor 200, the first exposed portion 122c, and the second exposed portion 133c are soldered at both ends in the longitudinal direction β of the shunt resistor 200. I attached. Therefore, the shunt resistor 200 is thermally expanded and contracted due to a temperature change as compared with the case where both ends of the shunt resistor 200 in the width direction γ orthogonal to the longitudinal direction β are soldered to the first exposed portion 122c and the second exposed portion 133c. When this occurs, the stress generated at the soldering point increases.

  Therefore, in this embodiment, the resin material of the formation part of the main body housing 111 is caused to flow in the interval direction W between the first exposed portion 122c and the second exposed portion 133c, and the coefficient of thermal expansion of the main body housing 111 is changed in the interval direction W. The thermal expansion coefficient of the shunt resistor 200 was approached most closely. Thereby, even if the shunt resistor 200, the first exposed portion 122c, and the second exposed portion 133c are soldered at both ends in the longitudinal direction β of the shunt resistor 200, a configuration in which the magnitude of the stress generated at the soldered portion is suppressed as much as possible. Can be realized.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, in the above embodiment, the output terminal 123 is integrally formed with the first bus bar 120 and the other output terminal 134 is integrally formed with the second bus bar 130. The output terminal may be formed as a separate component from the two bus bars.

  Further, the specifications (shape, size, layout, etc.) of the housing, the first and second bus bars, and other details can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Current sensor 11a Radiating part 41 Battery post 60 Wire harness 100 Housing with bus bar 110 Housing 116 Recessed part 120 First bus bar 122c First exposed part 123 Output terminal 130 Second bus bar 133c Second exposed part 134 Output terminal 160 Uneven part 161 Groove 200 Shunt resistor 300 Circuit board 400 Sealing portion X Current sensor longitudinal direction Y Current sensor width direction (direction orthogonal to the interval direction)
Z Current sensor height direction W Spacing direction between the first exposed portion and the second exposed portion

Claims (6)

A housing formed of an insulating resin material, a first bus bar inserted so as to be partially embedded in the housing, and attached to a battery post, and the housing in a state of being spaced apart from the first bus bar A second bus bar that is inserted so as to be partially embedded in and connected to the wire harness, and a housing with a bus bar,
A shunt resistor for electrically connecting the first bus bar and the second bus bar;
With
The housing is formed with a recess in which the first exposed portion of the first bus bar is exposed and the second exposed portion of the second bus bar is exposed,
A current sensor, wherein the shunt resistor electrically connects the first exposed portion and the second exposed portion in a state of being accommodated in the recess. A circuit board to which a potential difference between both ends of the shunt resistor is input;
The current sensor according to claim 1, wherein the circuit board is disposed in the recess. A pair of output terminals connected to the circuit board and outputting a potential difference between both ends of the shunt resistor to the circuit board;
The one output terminal of the pair of output terminals is formed integrally with the first bus bar, and the other output terminal is formed integrally with the second bus bar. The current sensor described.   The current sensor according to claim 1, wherein a sealing portion sealed with a sealing material softer than the resin material is provided in the recess.   A concavo-convex portion is formed in a surface portion corresponding to the concave portion of the surface exposed to the outside of the housing, and the concavo-convex portion is formed in the interval direction between the first exposed portion and the second exposed portion in the concave portion. The current sensor according to any one of claims 1 to 4, wherein a plurality of grooves extending along the gap are arranged at intervals in a direction orthogonal to the interval direction.   The current sensor according to claim 5, wherein the shunt resistor is formed such that a dimension in the interval direction is longer than a dimension in a direction orthogonal to the interval direction.

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