Socket terminal

Abstract

The purpose of the present invention is to enable easy connection work while obtaining high connection reliability between a pin terminal and a socket terminal. This socket terminal is connected to a pin terminal, and is provided with: a cylindrical part having a cylindrical base part and a plurality of spring contact pieces arranged in the circumferential direction of the cylindrical base part; and an urging member externally fitted to the cylindrical portion, each of the plurality of spring contact pieces extending from the cylindrical base portion in the axial direction of the cylindrical base portion and being elastically deformable in the radial direction of the cylindrical base portion, the urging member urging each of the plurality of spring contact pieces toward the inner circumferential side, and applying a contact pressure from each of the plurality of spring contact pieces against the pin terminal, the urging member urging each of the plurality of spring contact pieces being elastically deformable in the radial direction of the cylindrical base portion. The biasing member is made of a shape memory alloy that memorizes the shape so that the contact pressure is increased by temperature rise.

Description

Technical Field

[0001] The present invention relates to a socket terminal. Background Art

[0002] Patent Document 1 discloses a socket terminal having a barrel that can be mated with a mating pin terminal. Patent Document 1 discloses the following: the barrel of the socket terminal is composed of a base and a plurality of finger-like portions. The plurality of finger-like portions extend from the base in the axial direction of the barrel and are arranged at intervals along the circumference of the barrel. They are elastically flexible in the radial direction of the barrel. An outer spring ring is fitted around the outer circumference of the region of the barrel where the finger-like portions are formed. This outer spring ring applies a force to cause the finger-like portions to decrease in diameter radially inward of the barrel. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-054374 Summary of the Invention Problems to be solved by the invention

[0004] However, in order to improve vibration resistance and suppress contact heating, it is considered necessary to increase the contact pressure at the connection point between the pin terminal and the socket terminal. However, if the contact pressure is increased, the force required for connection will increase, which may deteriorate the connection workability.

[0005] Therefore, an object of the present disclosure is to achieve high connection reliability between a pin terminal and a socket terminal while facilitating the connection work. Solutions to Problems

[0006] The socket terminal of the present invention is connected to the pin terminal and comprises: a cylindrical portion having a cylindrical base and a plurality of spring contact pieces arranged along the circumferential direction of the cylindrical base; and a biasing member externally fitted to the cylindrical portion, wherein the plurality of spring contact pieces each extend from the cylindrical base along the axial direction of the cylindrical base and are elastically deformable in the radial direction of the cylindrical base, the biasing member biasing each of the plurality of spring contact pieces toward the inner circumference, thereby applying contact pressure relative to the pin terminal from each of the plurality of spring contact pieces, and the biasing member being formed of a shape memory alloy that memorizes its shape in such a way as to increase the contact pressure by increasing the temperature. Effects of the Invention

[0007] According to the present invention, high connection reliability between the pin terminal and the socket terminal can be obtained, and the connection work can be easily performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view showing a socket terminal according to the embodiment. Figure 2It is a perspective view showing a socket terminal according to the embodiment. Figure 3 It is an exploded perspective view showing the receptacle terminal. Figure 4 yes Figure 1 Cross-sectional view along line IV-IV. Figure 5 yes Figure 1 VV line cross-sectional view. DETAILED DESCRIPTION

[0009] [Description of Embodiments of the Invention] First, embodiments of the present invention will be described below.

[0010] The socket terminal of the present invention is as follows.

[0011] (1) A socket terminal connected to a pin terminal, comprising: a cylindrical portion having a cylindrical base and a plurality of spring contact pieces arranged along the circumference of the cylindrical base; and a biasing member externally embedded in the cylindrical portion, wherein the plurality of spring contact pieces each extend from the cylindrical base along the axial direction of the cylindrical base and are elastically deformable in the radial direction of the cylindrical base, the biasing member biases each of the plurality of spring contact pieces toward the inner circumference, thereby applying contact pressure relative to the pin terminal from each of the plurality of spring contact pieces, the biasing member being composed of a shape memory alloy, and the shape memory alloy memorizing a shape in such a manner as to increase the contact pressure by increasing the temperature.

[0012] This socket terminal facilitates connection by inserting the pin terminal into the barrel before the temperature rises. Furthermore, the increased temperature after connection increases the contact pressure between the spring contact piece and the pin terminal, thereby achieving high connection reliability. Furthermore, the spring contact pieces are arranged along the circumference of the cylindrical base and surround the outer circumference of the pin terminal. Therefore, heat generated at the connection point between the pin terminal and the barrel is easily transferred to the biasing member. This effectively increases contact pressure, achieving even higher connection reliability.

[0013] (2) In the socket terminal of (1), the cylindrical base may be formed in a cylindrical shape.

[0014] This allows the structure to be easily processed and suitable for connection to a round bar-shaped pin terminal.

[0015] (3) In the receptacle terminal of (2), the inner peripheral portion of each of the plurality of spring contact pieces may include an arcuate contact portion that protrudes toward the outer peripheral side when viewed in a direction along the central axis of the cylindrical base.

[0016] This increases the contact area of the arcuate contact portion with the pin terminal, improving the connection reliability between the pin terminal and the spring contact piece. In addition, the heat of the pin terminal is effectively transferred to the urging member.

[0017] (4) In any one of the socket terminals of (1) to (3), a slit may be present between two adjacent spring contact pieces among the plurality of spring contact pieces, and the biasing member may bias each of the plurality of spring contact pieces in a direction to reduce a gap of the slit.

[0018] In this case, the multiple spring contact pieces can contact the pin terminal while the gap is narrowed due to the applied force of the heated biasing member. This allows the spring contact pieces to contact as much of the pin terminal's circumference as possible, improving the connection reliability between the pin terminal and the spring contact pieces and effectively transferring heat from the pin terminal to the biasing member.

[0019] (5) In the receptacle terminal according to any one of (1) to (4), the biasing member may include a surrounding portion that surrounds the plurality of spring contact pieces from an outer periphery and a clamping and fixing portion that is clamped and fixed to the cylindrical portion.

[0020] Thus, in a state where the urging force before heating is small, it is possible to suppress the urging member from being displaced or falling off relative to the cylindrical portion.

[0021] (6) In any one of the socket terminals of (1) to (5), the urging member may contact a portion of each of the plurality of spring contact pieces closer to the tip side than the center in the extending direction to urge each of the plurality of spring contact pieces toward the inner peripheral side.

[0022] In this case, by urging the spring contact piece at a position away from the base end portion, the urging force of the pin terminal can be increased compared to a case where the urging member urges the base end side of the spring contact piece.

[0023] (7) In any one of the socket terminals of (1) to (6), each of the plurality of spring contact pieces may be in contact with the pin terminal at a position closer to the front end than the center in the extending direction.

[0024] In this case, the portion of the spring contact piece that contacts the pin terminal can be displaced significantly, thereby making it easy to adjust the contact state with respect to the pin terminal through slight deformation of the spring contact piece.

[0025] (8) In any one of the socket terminals of (1) to (7), the spring contact piece may include a base end side region extending from the tubular base and a top end side region extending from the base end side region toward a side away from the tubular base, an inclination angle of the top end side region relative to the central axis of the tubular base being smaller than an inclination angle of the base end side region relative to the central axis of the tubular base, and at least a portion of the top end side region being capable of contacting the pin terminal.

[0026] In this case, the tip side region with a small inclination angle can be brought into contact with the pin terminal with the largest possible contact area, or can be easily positioned as close to the pin terminal as possible.

[0027] (9) In the socket terminal of (8), the urging member may contact the distal end region to urge each of the plurality of spring contact pieces toward the inner peripheral side.

[0028] In this case, the urging member can be arranged near the heat generating portion, heat can be efficiently transferred to the urging member in contact with the distal end side region, and contact pressure can be effectively generated by the urging member.

[0029] (10) In the socket terminal of any one of (1) to (7), the urging member may be a Ni—Ti alloy or a Ni—Ti—Cu alloy.

[0030] Thus, as the temperature rises, the urging member can restore its original shape due to shape memory, and the elastic constant can be increased to increase the contact pressure between the spring contact piece and the pin terminal.

[0031] [Details of Embodiments of the Invention] Specific examples of the socket terminal of the present invention will be described below with reference to the accompanying drawings. The present invention is not limited to these examples but is defined by the claims, and is intended to encompass all modifications within the meaning and scope of the claims.

[0032] [Implementation Method] Hereinafter, the socket terminal according to the embodiment will be described. Figure 1 and Figure 2 It is a perspective view showing the socket terminal 20 . Figure 3 It is an exploded perspective view showing the socket terminal 20 . Figure 4 yes Figure 1 Cross-sectional view along line IV-IV. Figure 5 yes Figure 1 The VV line cross-sectional view. Figure 1 、 Figure 4 and Figure 5 , the pin terminal 10 is indicated by a two-dot chain line.

[0033] Pin terminal 10 is connected to socket terminal 20. For example, socket terminal 20 is connected to a first electrical device via an electrical transmission medium such as a bus bar or wire. Pin terminal 10 is connected to a second electrical device via an electrical transmission medium such as a bus bar or wire. The connection between pin terminal 10 and socket terminal 20 electrically connects the first and second electrical devices.

[0034] The socket terminal 20 and the pin terminal 10 may also be a combination of terminals for connecting power lines. For example, the socket terminal 20 is connected to the power source 18, and the pin terminal 10 is connected to the load 19 (see Figure 4 The pin terminal 10 is connected to the socket terminal 20, thereby electrically connecting the power source 18 and the load 19. In this case, a current suitable for operating the load 19 flows through the contact portion between the socket terminal 20 and the pin terminal 10. Depending on the type of load 19, such as a motor, a large current flows through this contact portion.

[0035] The socket terminal 20 includes a cylindrical portion 40 and a biasing member 50. The socket terminal 20 may be connected to the pin terminal 10 in a state housed in a resin housing H (see FIG. Figure 2 ).

[0036] In this embodiment, the barrel 40 is part of the terminal body 30. The terminal body 30 is formed, for example, by stamping a sheet of metal. The terminal body 30 is the portion that serves as the current path, and therefore is preferably formed from a metal having greater electrical conductivity than the biasing member 50. The terminal body 30 is formed, for example, from a copper plate or a copper alloy plate. The surface of the terminal body 30 may also be plated with a coating such as tin.

[0037] The terminal body 30 includes a barrel portion 40 and a wire connecting portion 32. The barrel portion 40 and the wire connecting portion 32 are connected in a straight line. Alternatively, the barrel portion 40 and the wire connecting portion 32 may be connected in a curved manner.

[0038] The exposed core portion of the wire W is crimped and connected to the wire connection portion 32. The wire connection portion may also be a structure in which a round terminal of the end of the wire W is connected by screw fastening or the like. The wire connection portion may also be a structure in which the end of the wire is connected by welding, soldering, or the like.

[0039] When a bus bar or the like is connected to a socket terminal, the socket terminal may include a bus bar connection portion that can be connected to the bus bar by screw fastening, welding, etc., instead of a wire connection portion. When a socket terminal and an electrical transmission medium are connected via a terminal, the socket terminal may include a terminal connection portion instead of a wire connection portion.

[0040] The cylindrical portion 40 includes a cylindrical base portion 42 and a plurality of spring contact pieces 44 .

[0041] The cylindrical base 42 is formed into a cylindrical shape. For example, the cylindrical base 42 is formed into a cylindrical shape, more specifically, a short cylindrical shape in which the axial length is smaller than the outer diameter. The cylindrical base 42 is formed, for example, by plastically deforming a strip of metal plate into a circular shape with both ends butted together. The wire connector 32 is connected to the middle portion of the strip of metal plate that constitutes the cylindrical base 42.

[0042] The cylindrical base portion is not necessarily a cylindrical shape. The cylindrical base portion 42 may be an elliptical cylindrical shape, or a polygonal cylindrical shape such as a triangular cylindrical shape or a quadrilateral cylindrical shape.

[0043] The plurality of spring contact pieces 44 are arranged along the circumferential direction of the cylindrical base 42. In this embodiment, the cylindrical portion 40 has three spring contact pieces 44. The cylindrical portion may also have two or four or more spring contact pieces.

[0044] The plurality of spring contact pieces 44 extend from the cylindrical base 42 in the axial direction of the cylindrical base 42. The plurality of spring contact pieces 44 do not need to be parallel to the axial direction of the cylindrical base 42. The plurality of spring contact pieces 44 only need to extend in the axial direction of the cylindrical base 42 within a range that allows the pin terminal 10 to be inserted and retained in the space surrounded by the plurality of spring contact pieces 44.

[0045] Furthermore, the spring contact piece 44 is elastically deformable in the radial direction of the cylindrical base 42. The base end of the spring contact piece 44 is connected to the end of the cylindrical base 42 opposite the wire connection portion 32. The spring contact piece 44 is in the shape of a plate, with the radial thickness of the cylindrical base 42 being smaller than the circumferential width of the cylindrical base 42. The spring contact piece 44 is elastically deformable inwardly and radially along the cylindrical base 42, with the connection portion with the cylindrical base 42 serving as the support portion.

[0046] In addition, slits S are present between the plurality of spring contact pieces 44. The plurality of spring contact pieces 44 can be elastically deformed inward and outward while the width of the slits S is changed.

[0047] The slit S can have a uniform width or a nonuniform width along the central axis of the cylindrical base 42. In this embodiment, the width of the slit S gradually decreases from the base end toward the tip end of the spring contact piece 44. This minimizes the gap between the arcuate contact portions 44F, described later.

[0048] The pin terminal 10 is in the shape of a round rod. The tip of the pin terminal 10 may also have a shape that tapers toward the tip, such as a hemispherical shape. The portion of the pin terminal 10 closer to the base end than the tip, where the diameter varies, is a main body portion continuous with a portion of the same diameter. For example, the pin terminal 10 may be a plated copper or copper alloy body.

[0049] The inner diameter of the cylindrical base 42 is larger than the outer diameter of the pin terminal 10. Figure 5 ) The diameter of the imaginary circle for connection at the nearest portion is smaller than the outer diameter of the pin terminal 10.

[0050] When the pin terminal 10 is inserted into the barrel 40 from the top end, the top end of the pin terminal 10 contacts the inner periphery of the multiple spring contact pieces 44. This causes the multiple spring contact pieces 44 to elastically deform outward. When the pin terminal 10 and the receptacle terminal 20 are connected, the main body of the pin terminal 10 contacts the inner periphery of the spring contact pieces 44. When the terminals 10 and 20 are connected, the multiple spring contact pieces 44 apply force to the pin terminal 10 due to the elastic force of the multiple spring contact pieces 44, which tend to return to their original shape.

[0051] The multiple spring contact pieces 44 can contact the pin terminal 10 at a position closer to the tip than the center of their extension direction. The inner circumference of each of the multiple spring contact pieces 44 includes an arcuate contact portion 44F that bulges outward when viewed along the central axis X of the cylindrical base 42. In this embodiment, when viewed along the central axis X, the spring contact piece 44 has an arcuate shape with the central axis X as the center of curvature. Therefore, when viewed along the central axis X, the inner circumference of the spring contact piece 44 has an arcuate shape with the central axis X as the center of curvature. The spring contact piece 44 has an arcuate edge formed at the tip, closest to the central axis X; this arcuate edge serves as the arcuate contact portion 44F. The portion of the spring contact piece 44 closer to the base than the arcuate contact portion 44F can also contact the pin terminal 10.

[0052] The spring contact piece 44 includes a base end side region R1 and a tip end side region R2 (see Figure 4 The proximal region R1 is a region extending from the cylindrical base 42 toward the distal end of the cylindrical portion 40. The distal region R2 is a region extending from the proximal region R1 toward a side away from the cylindrical base 42, that is, toward the distal end of the cylindrical portion 40.

[0053] The inclination angle θ2 of the distal region R2 relative to the central axis X is smaller than the inclination angle θ1 of the proximal region R1 relative to the central axis X. In other words, the distal region R2 is closer to a parallel position relative to the central axis X than the proximal region R1. Thus, the proximal region R1 allows the distal region R2 to be positioned close to the inner circumference of the pin terminal 10. Furthermore, the proximal region R1 allows the maximum possible area of the inner circumference of the proximal region R1 to contact the pin terminal 10 or to be positioned extremely close to the pin terminal 10.

[0054] The biasing member 50 is externally fitted to the cylindrical portion 40. The biasing member 50 biases the plurality of spring contact pieces 44 inward, exerting contact pressure on the pin terminal 10. Specifically, the spring contact pieces 44 are pressed against the pin terminal 10 by the biasing force of their own elastic force and the biasing force of the biasing member 50.

[0055] More specifically, the urging member 50 includes a surrounding portion 52 and a clamping and fixing portion 58. The urging member 50 is formed by, for example, punching a single metal plate.

[0056] The surrounding portion 52 is configured to surround the plurality of spring contact pieces 44 from its outer periphery. More specifically, the surrounding portion 52 includes a semi-cylindrical middle portion 52a and extended portions 52b extending from both ends of the middle portion 52a. The extended portions 52b are shaped so as to gradually taper from the middle portion 52a and are, in this case, trapezoidal.

[0057] The extended portion 52 b is connected to both ends of the intermediate portion 52 a , and the annular surrounding portion 52 is formed by the intermediate portion 52 a and the two extended portions 52 b .

[0058] Partial protrusions 52p are formed on each of the intermediate portion 52a and the two extended portions 52b. The partial protrusions 52p are, for example, hemispherical protrusions protruding toward the inner circumference of the surrounding portion 52. The plurality of partial protrusions 52p are formed at positions capable of contacting the plurality of spring contact pieces 44 from the outer circumference. The plurality of partial protrusions 52p are capable of contacting the outer circumferences of the plurality of spring contact pieces 44 in a one-to-one correspondence.

[0059] The inner diameter of the imaginary circle connecting the inner circumference tops of the plurality of partial protrusions 52p is smaller than the outer diameter of the imaginary circle passing through the outermost circumference of the portion of the plurality of spring contact pieces 44 to which the surrounding portion 52 is attached. Therefore, when the surrounding portion 52 is in contact with the plurality of spring contact pieces 44, the surrounding portion 52 is elastically deformed, expanding relative to its initial state. The elastic force of the surrounding portion 52, which attempts to restore its original shape, pushes the plurality of spring contact pieces 44 inward. The urging member 50 applies force to the plurality of spring contact pieces 44 in a direction that narrows the gap of the slit S.

[0060] In addition, the partial protrusion 52p is not necessarily required to be formed.

[0061] The biasing member 50 contacts the portion of the spring contact piece 44 closer to the tip than the center of extension, biasing the spring contact pieces 44 inward. The surrounding portion 52 is located on the outer periphery of the tip region R2 of the spring contact pieces 44. The surrounding portion 52 contacts the outer periphery of each tip region R2, biasing the spring contact pieces 44 inward. Therefore, heat generated at the contact point between the tip region R2 and the pin terminal 10 is effectively transferred to the surrounding portion 52.

[0062] The clamping and fixing portion 58 is a portion that is clamped and fixed to the cylindrical portion 40. In the present embodiment, the clamping and fixing portion 58 extends from the surrounding portion 52 toward the base end portion of one spring contact piece 44.

[0063] More specifically, the tightening and fixing portion 58 extends from the middle portion 52a of the surrounding portion 52. The tightening and fixing portion 58 extends along the outer peripheral surface of a spring contact piece 44 and reaches the base end portion of the spring contact piece 44. A holding portion 58b is provided at the top end portion of the tightening and fixing portion 58, and the holding portion 58b has holding pieces 58a extending to both sides. The pair of holding pieces 58a pass through the two side surfaces of the base end portion of the spring contact piece 44 and are bent in a manner facing the inner peripheral side, and the tightening and fixing portion 58 is tightened and fixed to the spring contact piece 44. A protrusion 44a protruding laterally can also be formed on the top end side of the spring contact piece 44 relative to the holding piece 58a. The protrusion 44a can limit the holding piece 58a from being displaced toward the top end side of the spring contact piece 44. The tightening and fixing portion can also be tightened and fixed to the cylindrical base.

[0064] The holding portion 58b and the surrounding portion 52 are connected by a central connecting piece 59a extending from the holding portion 58b toward the middle portion 52a, and a pair of side connecting pieces 59b extending from the holding portion 58b toward both ends of the middle portion 52a. An opening is formed between the central connecting piece 59a and the pair of side connecting pieces 59b. This reduces the thermal capacity of the urging member 50, effectively increasing its temperature.

[0065] The urging member 50 is made of a shape memory alloy that memorizes its shape so that the contact pressure between the spring contact piece 44 and the pin terminal 10 increases as the temperature rises.

[0066] The temperature before the contact pressure increases is, for example, the temperature at which the pin terminal 10 and the socket terminal 20 are connected, and is, for example, room temperature. Room temperature is, for example, 25°C ± 15°C. Hereinafter, when referring to temperatures, the temperature is expressed in degrees Celsius.

[0067] The temperature at which the contact pressure increases is a temperature higher than the temperature at which the pin terminal 10 and the socket terminal 20 are connected. The temperature at which the contact pressure increases may be, for example, a temperature exceeding room temperature. The temperature at which the contact pressure increases may be, for example, a temperature obtained by adding the effects of heating due to Joule heat, etc., to the ambient temperature in which the socket terminal 20 is used. The temperature at which the contact pressure increases may be, for example, a temperature of 50°C or higher.

[0068] That is, the urging member 50 may memorize the shape so that the contact pressure increases by increasing the temperature from the temperature range of 25 degrees ± 15 degrees to 50 degrees or higher.

[0069] Regarding the shape memory, it is sufficient that the shape is memorized so that the contact pressure is increased by changing the shape or the physical property value due to temperature increase.

[0070] For example, the virtual circle connecting the innermost portions of the plurality of spring contact pieces 44 of the biasing member 50 is defined as the minimum virtual circle. Here, the virtual circle connecting the inner circumference tips of the plurality of partial protrusions 52p is defined as the minimum virtual circle. It is considered that the shape is memorized such that the diameter of the minimum virtual circle after the contact pressure increases is smaller than the diameter of the minimum virtual circle at the temperature before the contact pressure increases. In other words, the surrounding portion 52 memorizes its shape such that the minimum virtual circle decreases with increasing temperature.

[0071] Furthermore, for example, the urging member 50 may memorize its shape so that the spring load can be increased by increasing the elastic coefficient, which is an example of a physical property value, due to temperature increase.

[0072] The shape memory alloy may be, for example, a Ni-Ti alloy or a Ni-Ti-Cu alloy. Ni-Ti alloy or Ni-Ti-Cu alloy changes shape as the temperature rises from 25°C ± 15°C to 50°C or higher, further increasing the elastic modulus to memorize the shape. This temperature increase can increase the force with which the urging member 50 urges the spring contact piece 44 inward.

[0073] Furthermore, the shape memory alloy may be an alloy other than the Ni—Ti alloy or the Ni—Ti—Cu alloy.

[0074] The operation of the socket terminal 20 will be described.

[0075] In the initial state, the urging member 50 is attached to the outer periphery of the cylindrical portion 40. Furthermore, before the temperature rises (e.g., at room temperature), the urging member 50 opens so that the diameter of the smallest imaginary circle increases. Therefore, the urging member 50 can be easily attached to the outer periphery of the cylindrical portion 40.

[0076] like Figure 1As shown, the pin terminal 10 is inserted and connected to the barrel 40 from its top end side. Then, the top end of the pin terminal 10 contacts the innermost portion of the plurality of spring contact pieces 44, and here contacts the arcuate contact portion 44F of the inner periphery of the top end side region R2. The plurality of spring contact pieces 44 are stretched outward to form a space between the plurality of spring contact pieces 44 into which the pin terminal 10 can be inserted. At this time, the force F1 based on the spring load of the spring contact piece 44 itself and the force F2 based on the spring load of the biasing member 50 act on the arcuate contact portion 44F of the spring contact piece 44 (see Figure 5 Therefore, during the insertion operation of the pin terminal 10, a contact pressure based on the resultant force of the force F1 and the force F2 acts between the spring contact piece 44 and the pin terminal 10. Therefore, a friction force proportional to the resultant force of the force F1 and the force F2 acts between the spring contact piece 44 and the pin terminal 10.

[0077] The force F2 is smaller than the force F3 after the temperature rises. Therefore, the force required to connect the pin terminal 10 can be reduced. Furthermore, by reducing the contact pressure during the connection operation, plating wear on the pin terminal 10 and the spring contact piece 44 can be suppressed. Consequently, when the pin terminal 10 and the spring contact piece 44 are connected, the plating's function of preventing oxidation and corrosion is utilized, resulting in high connection reliability.

[0078] Even when the pin terminal 10 is inserted and the temperature is normal, contact pressure due to the combined force of the force F1 and the force F2 acts between the pin terminal 10 and the spring contact piece 44 .

[0079] When the socket terminal 20 is used as a relay connection point of the circuit, it can be considered that the power supply 18 is electrically connected to one of the socket terminal 20 and the pin terminal 10, and the load 19 is electrically connected to the other. Therefore, current flows through the socket terminal 20 and the pin terminal 10.

[0080] When current flows through the socket terminal 20 and the pin terminal 10, the socket terminal 20 and the pin terminal 10 heat up due to Joule heat. It is also considered that the contact area between the socket terminal 20 and the pin terminal 10 is prone to heating due to Joule heat. The heat from the socket terminal 20 and the pin terminal 10 is transferred to the biasing member 50, causing the biasing member 50 to also heat up. As a result, the biasing member 50 deforms into a memorized shape, or the physical properties such as the elastic modulus of the biasing member 50 change, increasing the spring load of the biasing member 50. As a result, the force F3 applied by the biasing member 50 is greater than the aforementioned force F2. Consequently, the contact pressure between the pin terminal 10 and the spring contact piece 44 also increases. As a result, the socket terminal 20 and the pin terminal 10 maintain stable contact even under vibration. Furthermore, the electrical resistance between the socket terminal 20 and the pin terminal 10 is reduced, which can suppress excessive heating at the contact area.

[0081] For example, when the socket terminal 20 is used in a power supply circuit or a circuit to which a high voltage is applied, heat generation due to Joule heat can be expected. The high voltage is, for example, 60V or higher, more preferably 90V or higher.

[0082] However, the socket terminal 20 can also be applied to a signal circuit or a circuit to which a low voltage is applied.

[0083] The temperature of the urging member 50 may be increased by heat other than Joule heat in the socket terminal 20 and the pin terminal 10. For example, the temperature of the urging member 50 may be increased by heat from a control device or drive circuit around the socket terminal 20, heat from an internal combustion engine, or heat from a battery.

[0084] According to the socket terminal 20 constructed as described above, the biasing member 50 biases the plurality of spring contact pieces 44 toward the inner circumference, thereby applying contact pressure relative to the pin terminal 10. Furthermore, the biasing member 50 is made of a shape memory alloy that memorizes its shape in such a way that the contact pressure increases as the temperature rises. Therefore, by inserting and connecting the pin terminal into the barrel 40 before the temperature rises, the connection operation can be easily performed under relatively low contact pressure conditions. This makes it possible to easily perform the connection operation with a relatively low insertion force. Furthermore, plating wear of the socket terminal 20 and the pin terminal 10 during connection can be suppressed. Therefore, when the socket terminal 20 and the pin terminal 10 are connected, the plating function is utilized to ensure the reliability of the connection between the two.

[0085] Furthermore, the increased temperature after connection increases the contact pressure between the spring contact pieces 44 and the pin terminal 10, thereby achieving high connection reliability. Furthermore, multiple spring contact pieces 44 are arranged along the circumference of the cylindrical base 42, surrounding the outer periphery of the pin terminal 10. Therefore, heat generated in the pin terminal 10 and the cylindrical portion 40 is easily transferred to the biasing member 50 via the circumferentially arranged spring contact pieces 44. This effectively increases contact pressure, achieving even higher connection reliability.

[0086] Furthermore, when the temperature returns to normal, the contact pressure between the socket terminal 20 and the pin terminal 10 returns to a relatively low state, so that maintenance involving insertion and removal of the pin terminal 10 with respect to the socket terminal 20 can be easily performed.

[0087] For example, increasing the spring load on the terminal to improve vibration resistance and suppress heat generation at the contact points is a possibility. This would increase the force required for connection, potentially compromising connection workability. To improve connection workability, incorporating a lever that utilizes the principle of leverage or a structure that leverages the tightening force of bolts is being considered. These options could lead to increased weight, size, and complexity.

[0088] According to the socket terminal 20, the ease of connection work and the connection reliability can be improved while suppressing the increase in weight, size and size. In addition, the socket terminal 20 can also be applied to the connection structure using the above-mentioned rod or bolt.

[0089] Furthermore, if the cylindrical base 42 is formed into a cylindrical shape and the plurality of spring contact pieces 44 are arranged circumferentially via the cylindrical base 42 , a shape suitable for connection to the round rod-shaped pin terminal 10 can be formed that is easy to process.

[0090] Furthermore, if the inner periphery of the spring contact piece 44 includes an arcuate contact portion 44F that bulges outward when viewed along the center axis X, the contact area of the arcuate contact portion with the pin terminal 10 can be increased. This improves the connection reliability between the pin terminal and the spring contact piece. Furthermore, heat is easily transferred from the pin terminal 10 to the biasing member 50 via the spring contact piece 44, effectively increasing the temperature of the biasing member 50.

[0091] Furthermore, the biasing member 50 biases the multiple spring contact pieces 44 in a direction that narrows the gap of the slit S. This allows the spring contact pieces 44 to smoothly elastically deform inward and outward directions through the slit S. Furthermore, with the biasing member 50 biasing the spring contact pieces 44 and the slit S narrowed, the multiple spring contact pieces 44 can contact the pin terminal 10. This allows the spring contact pieces 44 to contact as much of the entire circumference of the pin terminal 10 as possible. This improves the connection reliability between the pin terminal 10 and the spring contact pieces 44. Furthermore, by narrowing the slit S, heat is easily transferred from the pin terminal 10 to the biasing member 50 via the spring contact pieces 44, effectively increasing the temperature of the biasing member 50.

[0092] Furthermore, the urging member 50 includes the clamping portion 58 clamped and fixed to the cylindrical portion 40 . Therefore, even when the force of the surrounding portion 52 is relatively small before heating, the urging member 50 is prevented from shifting or falling off relative to the cylindrical portion 40 .

[0093] Furthermore, the urging member 50 contacts the distal end of the spring contact pieces 44 and urges the spring contact pieces 44 inward. This increases the biasing force of the pin terminal 10 compared to when the urging member urges the base end of the spring contact pieces.

[0094] Furthermore, the multiple spring contact pieces 44 can contact the pin terminal 10 near the center of their extension direction, closer to the tip. Here, the arcuate contact portion 44F is located at the tip of the spring contact piece 44. The spring contact piece 44 elastically deforms by swinging about its base end. Therefore, compared to a case where the contact portion with the pin terminal is located near the base end of the spring contact piece, the arcuate contact portion 44F of the spring contact piece 44 that contacts the pin terminal 10 can be displaced more significantly. Thus, the contact state with the pin terminal 10 can be easily adjusted by slightly deforming the spring contact piece 44.

[0095] Furthermore, the spring contact piece 44 includes a base region R1 and a tip region R2. The tip region R2 has an inclination angle θ2 that is smaller than the inclination angle θ1 of the base region R1. At least a portion of the tip region R2 contacts the pin terminal 10. Therefore, the tip region R2, with its smaller inclination angle θ1, can contact the pin terminal 10 with the largest possible contact area, or the tip region R2 can be positioned as close to the outer circumference of the pin terminal 10 as possible. This effectively transfers heat generated by the pin terminal 10 to the biasing member 50 via the barrel 40. This facilitates increasing the biasing force of the biasing member 50.

[0096] Furthermore, the urging member 50 contacts the distal region R2 and urges the spring contact pieces 44 inward. Therefore, heat is efficiently transferred to the urging member 50 in contact with the distal region R2, and the urging member 50 can effectively generate contact pressure.

[0097] In addition, if the urging member 50 is made of Ni—Ti alloy or Ni—Ti—Cu alloy, it can restore its original shape due to shape memory when heated, and can increase its elastic modulus to increase the contact pressure between the socket terminal 20 and the pin terminal 10 .

[0098] Furthermore, the configurations described in the above-mentioned embodiment and the various modifications can be appropriately combined as long as they do not contradict each other. Description of Reference Numerals

[0099] 10-pin terminal 18 Power Supply 19 Load 20 socket terminals 30 terminal body 32 Wire connection 40 barrel 42 tubular base 44 Spring contact piece 44F arc contact part 44a tab 50 Force-applying member 52 Encirclement 52a Middle part 52b extension 52p partial protrusion 58 tightening fixing part 58a Holding piece 58b Holding part 59a Central connecting piece 59b Side connecting piece F1, F2, F3 forces H housing R1 proximal region R2 apical region S slit W Wire X center axis θ1 Inclination angle of the base end region θ2: Inclination angle of the distal end region

Claims

1. A socket terminal connected to a pin terminal, comprising: a cylindrical portion having a cylindrical base and a plurality of spring contact pieces arranged along a circumference of the cylindrical base; and A force-applying member is externally embedded in the cylindrical portion, Each of the plurality of spring contact pieces extends from the cylindrical base along the axial direction of the cylindrical base and is elastically deformable in the radial direction of the cylindrical base. The urging member urges each of the plurality of spring contact pieces toward the inner peripheral side, so that each of the plurality of spring contact pieces applies contact pressure to the pin terminal. The urging member is made of a shape memory alloy that memorizes its shape so as to increase the contact pressure as the temperature rises.

2. The socket terminal according to claim 1, wherein The cylindrical base is formed in a cylindrical shape.

3. The socket terminal according to claim 2, wherein: The inner peripheral portion of each of the plurality of spring contact pieces includes an arc-shaped contact portion that bulges toward the outer peripheral side when viewed in a direction along the central axis of the cylindrical base.

4. The socket terminal according to any one of claims 1 to 3, wherein: There is a slit between two adjacent spring contact pieces among the plurality of spring contact pieces, The urging member urges each of the plurality of spring contact pieces in a direction in which a gap of the slit is reduced.

5. The socket terminal according to any one of claims 1 to 3, wherein: The urging member includes a surrounding portion that surrounds the plurality of spring contact pieces from an outer periphery and a clamping and fixing portion that is clamped and fixed to the cylindrical portion.

6. The socket terminal according to any one of claims 1 to 3, wherein: The urging member contacts a portion of each of the plurality of spring contact pieces closer to the distal end than the center in the extending direction to urge each of the plurality of spring contact pieces toward the inner peripheral side.

7. The socket terminal according to any one of claims 1 to 3, wherein: Each of the plurality of spring contact pieces can be brought into contact with the pin terminal at a position closer to the distal end than the center in the extending direction.

8. The socket terminal according to any one of claims 1 to 3, wherein: The spring contact piece includes a base end region extending from the cylindrical base portion and a top end region extending from the base end region toward a side away from the cylindrical base portion. The inclination angle of the distal end region relative to the central axis of the tubular base is smaller than the inclination angle of the proximal end region relative to the central axis of the tubular base. At least a portion of the tip side region is contactable with the pin terminal.

9. The socket terminal according to claim 8, wherein: The urging member contacts the distal end region to urge each of the plurality of spring contact pieces toward the inner peripheral side.

10. The socket terminal according to any one of claims 1 to 3, wherein: The urging member is a Ni-Ti alloy or a Ni-Ti-Cu alloy.

Images