Contact element with shape memory material

Abstract

The invention relates to an electrical contact element for mating with a mating contact (20), comprising at least one elastically deflectable spring element (14), which has at least one contact point (18) for contacting the mating contact and is designed to generate a contact force (96) acting on the mating contact during operation, according to the invention, at least one section (22) made of a shape memory material is integrated into at least one contact element, which can be converted from a first shape into a second shape depending on the temperature, the at least one contact point of the contact element in the unstressed state is in a first contact position in a first shape of the section made of the shape memory material and in a second contact position in a second shape of the section made of the shape memory material. The contact element according to the present invention can reliably hold the mating contact even under difficult environmental conditions to provide low contact resistance and to be easily mated with the mating contact.

Description

Technical Field

[0001] The present invention relates to an electrical contact element for mating with a mating contact, and to a contact assembly comprising such a contact element and a mating plug. The present invention also relates to a method for automatically fixing an electrical contact assembly. Background Art

[0002] Contact elements are used in electrical plug connectors, for example, to establish electrical contact together with a mating contact. The contact elements usually have a spring element, which generates a contact force on the mating contact when the contact element and the mating contact are plugged together. The contact force is intended on the one hand to fix the mating contact in the socket and on the other hand to ensure a low contact resistance between the mating contact and the spring element and / or the spring element and the socket. For contact elements that are used in environments with high temperature fluctuations and / or strong vibrations, the contact force should be as high as possible.

[0003] However, high contact forces have disadvantages. For example, high contact forces are associated with high insertion forces that must be overcome when inserting or removing the mating contact. High insertion forces make it difficult to insert and / or remove the mating contact, especially under unfavorable conditions, such as in ergonomically unfavorable positions. In addition, high contact forces lead to increased wear of the contact elements and / or the mating contact due to high material removal. Summary of the invention

[0004] The problem underlying the present invention is therefore to provide a contact element which can reliably hold a mating contact even under difficult ambient conditions, which contact element has a low contact resistance and which is easy to mate with a mating contact.

[0005] The problem is solved by an electrical contact element for mating with a mating contact,

[0006] the contact element having at least one resiliently deflectable spring element, which has at least one contact point for contacting the mating contact and is designed to generate a contact force on the mating contact during operation,

[0007] At least one section made of shape memory material is integrated into the at least one contact element, the at least one section being able to transform from a first shape into a second shape depending on temperature,

[0008] The at least one contact point in the unstressed state of the contact element is located at a first contact position in the first shape of the shape memory material and is located at a second contact position in the second shape of the shape memory material.

[0009] An electrical contact element that provides two different contact positions depending on the temperature makes it possible to generate the contact force between the contact element and the mating contact as required. In this way, the contact force and therefore the insertion force between the contact element and the mating contact can be kept low during mating, in particular the same as or lower than a mating system without shape memory material. This makes assembly easier, in particular under ergonomically difficult conditions. If the temperature rises during operation of the electrical contact element, which also occurs, for example, under heavy mechanical stress and due to friction caused by vibrations, the shape memory material transforms into its second shape. As a result, the contact position of the shape memory material shifts, which leads to an increase in the contact force between the contact element and the mating contact. This ensures that the mating contact is securely seated in the contact element during operation. Therefore, the contact element has the advantage of being easy to install and ensuring that the mating contact is securely seated exactly when required during operation.

[0010] The above invention can be further improved by the following features, each of which is preferred and can be combined with each other as desired.

[0011] The shape memory material can be at least one material selected from the group consisting of shape memory alloys (e.g., NiTi, NiTiCu, FeMnSi, CuZn, CuZnAl, CuAlNi, ZnAuCu, FeNiAl), shape memory ceramics (e.g., zirconium (IV) oxide, bismuth iron oxide, vanadium (IV) oxide) and / or shape memory polymers (e.g., phase-separated linear (multi) block copolymers, amorphous polynorbornene, thermally cross-linked poly(ethylene-co-vinyl acetate), acrylates, cross-linked copolymers of caprolactone and glycolic acid).

[0012] The shape memory material can have a predetermined switching temperature, exceeding which causes the shape memory material section to change from a first shape to a second shape. Preferably, the switching temperature can be adapted to the application, in particular to the temperatures occurring in the respective contact element under predetermined currents and / or vibrations. Preferably, the at least one section of the contact element made of shape memory material can have its first shape at room temperature.

[0013] The section made of shape memory material can represent only one section of the contact element or several sections spaced apart from one another. The section made of shape memory material can also be a coating. In particular, the coating can be located on the at least one spring element and / or can be a region between the contact point and the base body of the contact element, on which the at least one spring element is located. This region can extend over the entire cross section of the contact element or only over a part of the cross section of the contact element.

[0014] In one configuration, the contact element can also be made completely of a shape memory material. For example, the contact element can consist only of a spring element.

[0015] According to another embodiment, at least one of the at least one sections made of shape memory material can have a one-way memory effect. In particular, the second shape can be irreversible, so that the first state of the shape memory material cannot be restored after the conversion to the second state. This configuration has the advantage that the contact element that has been converted to the second shape of the shape memory material cannot be converted again (in particular not unintentionally) to the first shape of the shape memory material. This ensures that, for example, the contact element in the second shape remains dimensionally stable even under the influence of fluctuating operating conditions (e.g. temperature, vibrations, current). In addition, the contact element of this embodiment provides the possibility of establishing a fixed, in particular non-detachable connection with the second element.

[0016] According to another aspect, at least one of the at least one sections made of shape memory material can have a two-way memory effect. As a result of the two-way memory effect, at least one section of the contact element made of shape memory material can be reversibly deformed between a first shape and a second shape. In particular, this deformation can be reversible, depending on the temperature. Due to the reversible convertibility between the first shape and the second shape of the section, the contact element can be reused. If the contact element is used together with a mating contact, the connection can be designed to be reversible and detachable without damage.

[0017] Furthermore, at least one section may be made of a shape memory material having a one-way memory effect, and at least one other section may be made of a shape memory material having a two-way memory effect.

[0018] According to another preferred embodiment, the contact element may have a socket for inserting the mating contact, and at least one spring element may be movable toward the socket in a second shape relative to the first shape. This configuration allows the mating contact to be inserted into the contact element, whereby a mechanical and / or electrical connection may be established between the mating contact and the contact element. Due to the mobility of the spring element toward the socket, the contact element may exert a contact force on the mating contact, which generally improves the stability of the mating or connection of the mating contact in the contact element.

[0019] In the second shape of the shape memory material, the clear width of the socket may be smaller than the clear width in the first shape of the shape memory material. If a mating contact according to this embodiment is inserted into a contact element, the section of the contact element made of shape memory material is in the first shape, the insertion process is facilitated because the clear width of the socket is greater than the clear width of the section made of shape memory material when it is in the second shape.

[0020] According to another preferred embodiment, the contact element in the first shape can have smaller outer dimensions than the contact element in the second shape. Such a contact element is particularly easy to install in the first shape - for example, if the contact element is to be inserted into a socket - while a tight fit of the contact element can be achieved after reaching the second shape.

[0021] In the first shape, the contact element can have a larger inner diameter than in the second shape. However, the inner diameter of the contact element in the first shape can also be smaller than the inner diameter in the second shape. The inner diameter can be understood, for example, as the smallest distance in the radial direction between two points of the contact element, which are spaced closest to the longitudinal axis of the contact element.

[0022] According to another embodiment, the at least one spring element may be formed by a tongue which is punched out of the remaining contact element.Such a contact element may be manufactured cost-effectively, in particular as part of an automated production process.

[0023] According to another aspect, the contact element can be designed to automatically deform from a first shape to a second shape when the current flowing through the contact element exceeds a predetermined minimum value. The shape of such a contact element can be easily adjusted by applying a current, which enables a controlled control system. Furthermore, depending on the current flow, the contact element can automatically deform into a preferred shape for the corresponding current flow, which improves performance.

[0024] The contact element can also be designed to deform from the second shape to the first shape if the current flowing through the contact element drops below a predetermined limit value. In this case, the limit value can be less than or greater than the minimum value. The minimum value and / or the limit value can correspond to the temperature of the contact element, which can in particular be predetermined.

[0025] According to a further preferred embodiment, the contact element may be a contact element from the following contact element group:

[0026] - radial springs, which are bent into rings;

[0027] - Crown spring;

[0028] - shielding sleeve;

[0029] - contact pins;

[0030] - Crimp plug or crimp socket;

[0031] - A clamp or an insert for a clamp.

[0032] The contact element according to this embodiment can be flexibly adapted to different applications and fields of use. For example, the type of contact element can be selected according to many criteria, such as the required contact force, manufacturing costs, assembly effort, mechanical load capacity or availability.

[0033] In the case of a helical spring bent into a loop, the entire contact element may represent a resiliently deflectable spring element.The contact points for contacting the mating contact may be those points on the radial spring which are furthest inwards in the radial direction.

[0034] The crown spring may have a spring element extending from a ring in the axial direction. In particular, the spring element may extend in the axial direction between two rings that are opposite to each other in the longitudinal direction of the crown spring. Furthermore, there may also be several spring elements distributed in the circumferential direction around the central receptacle. In particular, the spring element may have a concave or convex shape in the longitudinal direction.

[0035] The shielding sleeve may be a substantially cylindrical component on which a plurality of spring elements are arranged spaced apart from one another in the circumferential direction. The spring elements may be deflected inwardly in the radial direction and / or deflected outwardly in the radial direction. Preferably, the spring elements of the shielding sleeve are integrally formed with the substantially cylindrical body of the shielding sleeve. At least one spring element of the shielding sleeve may also have a region that is curved in the radial direction. In particular, the curvature may be concave or convex.

[0036] The spring element of the contact pin can extend along the longitudinal axis of the contact pin and be bent relative to the longitudinal axis of the contact pin. The bend is preferably convex, however it can also be concave. The contact pin can have a plurality of spring elements protruding from the contact pin at intervals from each other in the circumferential direction of the contact pin.

[0037] If the contact element is a clamp or an insert for a clamp, the spring element can be formed by legs or arms that are opposite to each other with respect to the longitudinal axis of the contact element. The legs or arms can be designed to be elastically deflectable inwardly in the radial direction and / or outwardly in the radial direction. In particular, when at least one segment made of shape memory material changes from a first shape to a second shape or from a second shape to a first shape, the legs or arms can perform a clamping movement directed inwardly in the radial direction or outwardly in the radial direction.

[0038] According to another aspect, a contact assembly can be provided, which has a contact element and a mating contact plugged together with the contact element, wherein the contact force exerted by the contact element on the mating contact in the first shape can be smaller than the contact force in the second shape. During operation, different contact forces between the contact element and the mating contact may be required or preferred, for example, depending on the vibrations, temperature or currents that occur. Since the contact forces exerted in the two shapes of the contact element are different, the contact forces can be set as required. As a result, for example, the material load is reduced and the durability is increased.

[0039] According to another preferred embodiment, the surface area of ​​the contact surface where the contact element and the mating contact come into contact can be smaller in the first shape than in the second shape. When the contact element and the mating contact move relative to each other, the reduction in the surface area of ​​the contact surface reduces the friction between the contact element and the mating contact. Therefore, such a contact assembly facilitates the alignment of the contact element relative to the mating contact and reduces wear. In addition, since the contact force is distributed over a larger contact surface than in the first shape, the surface pressure and thus the material load can be reduced in the second shape.

[0040] According to another embodiment, the contact assembly may have a first intended operating state for conducting current between the contact element and the mating contact and a second intended operating state for conducting current between the contact element and the mating contact, wherein when the contact element is in a first shape, the contact assembly is in the first operating state, and when the contact element is in a second shape, the contact assembly is in the second operating state.

[0041] In particular, the intended operating state can be achieved by using the contact assembly or contact element according to the intended use. For example, the intended use is defined in the Machinery Directive 2006 / 42 / EC. In addition, the intended use of the contact assembly or contact element is clearly and understandably specified in the technical documentation and / or operating instructions of the contact assembly or contact element based on legal requirements.

[0042] In the first expected operating state, the contact assembly may be fully mated and / or complete. In particular, the contact assembly may be fully functional in the first expected operating state. In the second operating state, the contact force may be increased compared to the first operating state. In addition, the contact force in the first operating state may correspond to the contact force of a contact element not equipped with a shape memory material.

[0043] According to another preferred embodiment, a group with a plurality of contact elements can be provided, wherein the group can have a first contact element and a second contact element, the first contact element having a section made of a shape memory material in a first configuration, the second contact element having a section made of a shape memory material in a second configuration different from the first configuration, wherein the first contact element and the second contact element have the same configuration except for the section made of the shape memory material. The differently shaped sections allow the contact elements to be flexibly adapted to different requirements. At the same time, the manufacturing costs of this group with a plurality of contact elements are limited, because, except for the sections, the contact elements do not differ in structure.

[0044] The first contact element may have a different transition temperature than the second contact element, at which transition temperature the segment changes from the first shape to the second shape.

[0045] At least one section made of shape memory material can be plastically deformed, for example as a tongue bent out of the plane of the metal sheet, as a crimping part (crimping wing) of a crimping connection or as a bending spring. In this case, the change from the first shape to the second shape also increases the contact force.

[0046] According to another aspect, a method for automatically fixing an electrical contact assembly can be provided, the electrical contact assembly comprising a contact element and a mating contact mating with the contact element, wherein the contact element can comprise at least one shape memory material segment, which automatically deforms from a first shape into a second shape when the temperature increases due to vibrations and / or current flow between the contact element and the mating contact, wherein in the first shape, the contact force applied by the contact element on the mating contact is lower than the contact force in the second shape. Under the influence of vibrations, there is a risk that the mating contact will detach from the contact element or that the quality of the electrical connection between the mating contact and the contact element will deteriorate. The transition of the segment from the first shape to the second shape triggered by the temperature increase during operation can increase the contact force, which tightens the fit of the mating contact in the contact element, thereby improving the quality of the electrical connection. In addition, an unintentional loosening of the connection is prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the following, the present invention is explained in more detail by the embodiments with reference to the accompanying drawings. If the technical effects associated with the individual features according to the above-described embodiments are not important, the individual features may be omitted in the following embodiments. On the contrary, if the technical effects associated with the features described above but not present in the following embodiments are important for a specific application, the features may be added to the embodiments.

[0048] In the following, the same reference numerals are used for elements that correspond to one another in terms of structure and / or function.

[0049] In the attached picture:

[0050] Figure 1 is a schematic perspective view of a contact element according to a possible embodiment;

[0051] Figure 2 yes Figure 1 A schematic cross-sectional view of a contact element;

[0052] Figure 3 is a schematic perspective view of a contact element in a possible configuration as a radial spring contact;

[0053] Figure 4 is a schematic perspective view of a contact element in a possible configuration as a crown spring;

[0054] Figure 5 is a schematic perspective view of a contact element in another possible configuration as a crown spring;

[0055] Figure 6 is a schematic perspective view of a contact element in a possible configuration as a shielding sleeve;

[0056] Figure 7 is a schematic perspective view of a contact element in a possible configuration as a contact pin;

[0057] Figure 8 is a schematic perspective view of a set of a plurality of contact elements according to a possible embodiment;

[0058] Fig. 9 is a schematic perspective view of a contact element as a crimp contact in a possible embodiment;

[0059] Fig.10 is a schematic perspective view of a contact assembly according to a possible embodiment;

[0060] Fig.11 yes Fig.10 A schematic cross-sectional view of a contact assembly. DETAILED DESCRIPTION

[0061] In the following, reference Figure 1 and Figure 2 The electrical contact elements are described by way of example.

[0062] Figure 1 and Figure 2The electrical contact element 1 is shown in a stress-free state 2. The contact element 1 is designed as a clamp 4 having two legs 8 arranged symmetrically opposite one another with respect to a longitudinal axis 6 of the contact element 1. The distance 10 between the legs 8 in a radial direction 12 varies along the longitudinal axis 6 of the contact element 1. In the embodiment shown, the legs 8 each serve as a spring element 14, which can be elastically deflected in the radial direction 12. If the legs 8 or the spring elements 14 are deflected outwardly 66 in the radial direction, the legs 8 or the spring elements 14 move away from one another, and if the legs 8 or the spring elements 14 are deflected inwardly 16 in the radial direction, the legs 8 or the spring elements 14 move towards one another.

[0063] In the embodiment shown, each spring element 14 has a contact point 18 which is arranged for contact with a mating contact 20 (see Fig.10 A total of four contact points 18 are arranged on the contact element 1 , which are located opposite one another with respect to the longitudinal axis 6 of the contact element 1 and project inwardly in the radial direction 16 .

[0064] The contact element 1 also has two sections made of a shape memory material 22. In this case, the shape memory material may include at least one material from the group of shape memory alloys, shape memory ceramics and shape memory polymers. In the embodiment shown, the sections 22 are each arranged at a contact point 18. Figure 1 As shown, the shape memory material section 22 is in a first shape 24 and the contact point 18 is at a first contact location 26 .

[0065] Depending on the temperature, the segment 22 can be transformed from the first shape 24 to the second shape 28, which is Figure 2 In the cross-sectional view shown schematically and purely by way of example by a dashed outline, in the second shape 28, the contact point 18 of the contact element 1 is located at a second contact position 30. In the embodiment shown, the contact point 18 in the second shape 28 of the segment 22 is located further inwards in the radial direction 16, i.e. closer to the longitudinal axis 6 of the contact element 1, than the contact point 18 in the first shape 24.

[0066] According to a possible embodiment, the entire contact element 1 or the entire spring element 14 can be made of a shape memory material, or the section 22 made of a shape memory material can extend over the entire contact element 1 or the entire spring element 14. In particular, when the section 22 made of a shape memory material is transformed from its first shape 24 to its second shape 28, the spring element 14 can be elastically deflected in the radial direction 16 inwards. This allows the legs 8 of the clamp 4 to perform a clamping movement in the radial direction 16 inwards.

[0067] The contact element 1 further has an outer dimension 32. The outer dimension 32 denotes the distance in the radial direction 16 between the points of the spring element 14 or the legs 8 of the clamp 4 which are furthest from the longitudinal axis 6 of the contact element 1. In the embodiment shown, the outer dimension 32 of the contact element 1 does not decrease when the contact element 1 is transformed from the first shape 24 to the second shape 28. However, according to another embodiment, the contact element 1 in the first shape 24 may also have an outer dimension 32 which is smaller or larger than in the second shape 28.

[0068] The contact element 1 may also have a socket 34. The socket 34 may represent an opening 36 located at an axial end 38 of the contact element 1. The mating contact 20 (see Fig.10 ) The contact element 1 can be inserted or pulled out via the socket 34 or the opening 36 along the longitudinal axis 6 of the contact element 1 .

[0069] As shown below, the contact element 1 is not fixed to Figure 1 and Figure 2 Instead, the contact element 1 can be designed as, for example, a radial spring 40 bent into a ring, a crown spring 42 , a shield sleeve 44 , a contact pin 46 , a crimping plug 48 or a crimping socket 50 , a clamp 8 or an insert 52 for the clamp 8 .

[0070] These various configurations of the contact elements are described in detail below.

[0071] according to Figure 3 In the embodiment shown, the contact element 1 is designed as a radial spring 40, which is bent into a ring or annulus. In the embodiment shown, the entire contact element 1 represents an elastically deflectable spring element 14. The contact points 18 for contacting the mating contact 20 can be, for example, those points of the radial spring 40 that are farthest inward in the radial direction 16. Figure 3 As shown, the contact point 18 can be arranged on the inner contour 56 of the radial spring 40. The inner contour 56 is Figure 3 In the embodiment shown, the segment 22 made of shape memory material is arranged at the contact point 18. However, according to another embodiment, the entire radial spring 40 can also be made of shape memory material, or the segment 22 can extend over the entire radial spring 40.

[0072] In the embodiment shown, the mating contact 20 is inserted into the contact element 1 or the radial spring 40. The mating contact 20 and the contact element 1 or the radial spring 40 form a contact assembly 92. The mating contact 20 is in contact with the contact point 18 of the contact element 1 or the radial spring 40, so that the outer side 98 of the cylindrical mating contact 20 extends along the inner contour 56 of the radial spring 40. The contact element 1 or the radial spring 40 exerts a contact force 96 acting inwardly in the radial direction on the outer side 98 of the mating contact 20.

[0073] During operation, the shape memory material section 22 changes from the first shape 24 to the second shape 28. The changeover can be initiated, for example, by a temperature increase of the contact element 1 or the radial spring 40, by a current flow between the contact element 1 or the radial spring 40 and the mating contact 20, or by vibrations and / or friction between the contact element 1 or the radial spring 40 and the outer side 98 of the mating contact 20.

[0074] By converting the section 22 made of shape memory material from the first shape 24 to the second shape 28, the contact element 1 or the radial spring 40 has a tendency to deform inwardly in the radial direction 16. Since this deformation is resisted by the mating contact 20, the contact force 96 between the contact element 1 or the radial spring 40 and the outer side 98 of the mating contact 20 increases.

[0075] according to Figure 4 and Figure 5 In the embodiment shown, the contact element 1 can also be designed as a crown spring 42. The crown spring 42 has a substantially cylindrical shape, and an annular section 60 is arranged at the axial end 58 of the crown spring 42. Between the annular sections 60, a plurality of spring elements 14 extend along the longitudinal axis 64 of the crown spring 42, and the plurality of spring elements 14 are arranged adjacent to each other in the circumferential direction 62. Figure 4 In the embodiment shown, the spring element 14 of the crown spring 42 is curved concavely relative to the longitudinal axis 64 of the crown spring 42, while Figure 5 In the embodiment shown, the spring element 14 of the crown spring 42 extends helically about the longitudinal axis 64 of the crown spring 42. Furthermore, the spring element 14 of the crown spring 42 can be curved convexly—at least partially—relative to the longitudinal axis 64 of the crown spring 42. Figure 4 and Figure 5 In the embodiment shown, the shape memory material section 22 extends over the entire spring element 14. The spring elements 14 each have a contact point 18 which is located in the center of each spring element 14 relative to the longitudinal axis 64 of the crown spring 42.

[0076] exist Figure 4 and Figure 5 In each case, a contact assembly 92 is shown, which comprises a mating contact 20 which is inserted into a contact element 1 or a crown spring 42. The outer side 98 of the mating contact 20 is schematically shown as a dashed line. The mating contact 20 is in contact with the contact point 18 of the contact element 1 or the crown spring 42. The contact element 1 or the crown spring 42 causes a contact force 96 which acts on the outer side 98 of the mating contact 20 in the radial direction 16 inwards.

[0077] In operation, the shape memory material section 22 or the spring element 14 changes from the first shape 24 to the second shape 28. The changeover can be initiated, for example, by a temperature increase of the contact element 1 or the crown spring 42, by a current flow between the contact element 1 or the crown spring 42 and the mating contact 20, or by vibrations and / or friction between the contact element 1 or the crown spring 42 and the outer side 98 of the mating contact 20.

[0078] By converting the shape memory material section 22 from the first shape 24 to the second shape 28, the spring element 14 has a tendency to deform in radial direction inwards 16. Since this deformation is resisted by the mating contact 20, the contact force 96 between the contact element 1 or the crown spring 42 and the outer side 98 of the mating contact 20 increases.

[0079] from Figure 6 As can be seen in the figure, the contact element 1 can be designed as a shielding sleeve 44. The shielding sleeve 44 shown is a substantially cylindrical component on which a plurality of spring elements 14 are arranged spaced apart from each other in the circumferential direction 62. The spring elements 14 can be deflected inwardly 16 in the radial direction and / or outwardly 66 in the radial direction. Preferably, the spring elements 14 of the shielding sleeve 44 are formed integrally with the substantially cylindrical body 68 of the shielding sleeve 44. Therefore, in the embodiment shown, the spring elements 14 of the contact element 1 represent tongues 70 punched out of the contact element 1 or the shielding sleeve 44, in particular tongues 70 punched out of the body 68 of the shielding sleeve 44. According to another embodiment, the spring elements 14 can also be connected to the shielding sleeve 44 or the contact element 1 in a form-fitting, force-fitting or other material-fitting manner. At least one spring element 14 of the shielding sleeve 44 can also have a section 71 bent in the radial direction. In particular, the bend can be concave or convex. In the exemplary embodiment shown, the contact point 18 of the contact element 1 or the shielding sleeve 44 is arranged on the outer side of the section 71. Furthermore, the section 22 made of shape-memory material extends over the entire spring element 14 or the tongue 70.

[0080] Figure 6 Also shown is a contact assembly 92, which includes a mating contact 20 and a shielding sleeve 44 inserted into the mating contact 20. In operation, in particular under the influence of temperature increase, current flow and vibrations, the segment 22 made of shape memory material or the spring element 14 is transformed from the first shape 24 to the second shape 28. As a result, the spring element 14 has a tendency to deform outwards 66 in the radial direction. Since the mating contact 20 (indicated by the dashed line) prevents this deformation, the contact force 96 between the contact element 1 or the shielding sleeve 44 and the inner side 110 of the mating contact 20 increases. As a result, the fit of the shielding sleeve 44 in the mating contact 20 is tighter in the second shape than in the first shape.

[0081] exist Figure 7 In the embodiment shown, the contact element 1 is designed as a contact pin 46. The contact pin 46 shown is essentially rod-shaped and has a press-fit section 74 at one axial end 72. The press-fit section 74 has two base portions 76 spaced apart along the longitudinal axis 78 of the contact pin 46, between which a plurality of spring elements 14 extend. The spring elements 14 are arranged side by side along the circumferential direction 62 and extend along the longitudinal axis 78 of the contact pin 46. In the embodiment shown, the spring elements 14 are convex relative to the longitudinal axis 78 of the contact pin 46 or are bent outwards 66 in the radial direction. Furthermore, the spring elements 14 can also be concave or not bent at all.

[0082] exist Figure 7 In the embodiment shown, the sections 22 made of shape-memory material are those sections of the spring element 14 which are spaced furthest apart from the longitudinal axis 78 of the contact pin 46 in the radial direction 66. According to further configurations, however, at least one spring element 14 can also be made completely of shape-memory material, or the section 22 made of shape-memory material can extend over at least one entire spring element 14. Furthermore, the entire contact pin 46 can also be made of shape-memory material, or the section 22 made of shape-memory material can extend over the entire contact pin 46.

[0083] The press-fit section 74 of the contact element 1 or the contact pin 46 can be used, for example, to establish a force-fit connection, in particular a press-fit, between the contact element 1 or the contact pin 46 and a component, such as a PCB. For this purpose, the press-fit section 74 of the contact pin 46 or the contact element 1 can be inserted into the PCB when the section 22 made of shape memory material is in the first shape 24. After the insertion, the section 22 can be converted into the second shape 28. The conversion of the section 22 from the first shape 24 to the second shape 28 can be initiated, for example, by a temperature change or by applying an electric current to the contact element 1 or by vibration.

[0084] As a result of the transition from the first shape 24 to the second shape 28, the spring element 14 is deformed in the radial direction outwards 66. This causes the contact point 18 to be displaced from the first contact position 26 to the second contact position 30, which is spaced further away from the longitudinal axis 6 of the contact element 1 or the longitudinal axis 78 of the contact pin 46 in the radial direction outwards 66 than the first contact position 26. Figure 7 In FIG. 2 , the section 22 in the second shape 28 or the contact point 18 of the spring element 14 at the second contact position 30 is schematically indicated as a dashed line.

[0085] like Figure 8As shown, a group 80 with a plurality of contact elements 1 can also be provided. In the embodiment shown, the contact element 1 represents a contact pin 46, which is arranged parallel to each other and connected to each other via a bridge 82. However, the contact pins 46 can also be connected to each other in other ways or not at all. The group 80 can also include a first contact element 84 and a second contact element 86, which have the same construction except for the shape memory material section 22. In particular, the first contact element 84 can have a plurality of sections 88 manufactured in a first construction, and the second contact element 86 can have a plurality of sections 90 manufactured in a second construction.

[0086] like Fig. 9 As shown, the contact element 1 can also be designed as a crimping plug 48 or a crimping socket 50. The crimping socket 50 can have crimping wings 106 extending tangentially to the substantially cylindrical shape of the crimping socket 50. During the crimping process, the crimping wings 106 can be deformed along the circumferential direction 62 and thus, for example, grip around a mating contact 20 (not shown) (e.g., a cable) inserted into the crimping socket. In the embodiment shown, the crimping socket 50 has a plurality of shape memory material sections 22 spaced apart along the longitudinal axis 6. The shape memory material sections 22 extend along the circumferential direction 62 and on the inner side 108 of the crimping socket 50.

[0087] During operation, in particular due to temperature increase, current flow and / or vibrations, the shape memory material section 22 transforms from the first shape 24 to the second shape 28. As a result, the crimping wings 106 of the crimping socket 50 deform and grip around the mating contact 20. Since the mating contact 20 cannot - or can only partially yield to the deformation in the case where the mating contact 20 is designed, for example, as a cable with an elastic jacket, the contact force 96 between the mating contact 20 and the crimping wings increases.

[0088] In the following, reference Fig.10 and Fig.11 The structure and function of the contact assembly 92 are described.

[0089] The contact assembly 92 includes a mating contact 20 and a contact element 1, which in the embodiment shown corresponds to Figure 1The clamp 4 shown in . The mating contact 20 is fully inserted into the contact element 1 or is mated with the contact element 1. The longitudinal axis 6 of the contact element 1 extends along the longitudinal axis 94 of the mating contact 20, and the mating contact 20 penetrates the socket 34 or the opening 36 of the contact element 1. The section 22 of the contact element 1 made of shape memory material is located in the first shape 24. The spring element 14 generates a contact force 96, which acts on the outer side 98 of the mating contact 20 in the radial direction 16 inward. The contact point 18 of the spring element 14 is in contact with the outer side 98 of the mating contact 20. In particular, the contact element 1 and the mating contact 20 can be in contact at the contact surface 100, such as at Fig.11 It can be clearly seen in.

[0090] During operation, current flows between the contact element 1 and the mating contact 20. In addition, the contact assembly 1 may be subjected to vibrations and mechanical stresses during operation, which cause friction between the contact element 1 and the mating contact 20. According to a possible embodiment, when current flows and the contact element 1 is in the first shape 24, the contact assembly 92 may be in the first intended operating state 102. Fig.10 The contact assembly 92 is shown in a first intended operating state 102 .

[0091] During operation, in particular in the first intended operating state 102, heat is generated between the mating contact 20 and the contact element 1 due to current flow and / or vibrations. As a result, the temperature of the contact element 1 increases. After a certain temperature increase or when a transition temperature is reached, at least one shape memory material segment 22 is transformed from the first shape 24 to the second shape 28 (at Figure 2 best seen in ).

[0092] According to a possible embodiment, if the current flowing through the contact assembly 1 exceeds a minimum value, the contact element 1 may also automatically deform from the first shape 24 to the second shape 28. The minimum value may be predetermined.

[0093] Due to the transformation of the segment 22 from the first shape 24 to the second shape 28, the spring element 14 has a tendency to deflect inwardly 16 in the radial direction. In particular, the contact point 18 attempts to move from the first contact position 26 to the second contact position 30. However, since the contact element 1 is not in the unstressed state 2 and the deflection of the spring element 14 inwardly 16 in the radial direction is blocked by the inserted mating contact 20, the contact force 96 between the mating contact 20 and the contact element 1 increases. After the transformation of the contact element 1 into the second shape 28, the contact assembly 92 may in particular be in the second expected state 104. The mating contact 20 may have a tighter fit in the contact element 1 in the second shape 28 than in the first shape 24.

[0094] If the segment 22 has a two-way memory effect, the segment 22 can be switched again from the second shape 28 to the first shape 24. The switch can be initiated, for example, by a change in temperature, a change in current or as a result of vibrations.

[0095] Reference Mark

[0096] 1Contact element

[0097] 2 No force state

[0098] 4. Fixture

[0099] 6 Longitudinal axis of contact element

[0100] 8 Legs

[0101] 10 Distance between legs

[0102] 12 Radial direction

[0103] 14 Spring element

[0104] 16 radial direction inward

[0105] 18 contact points

[0106] 20 Mating contacts

[0107] 22 Segments made of shape memory material

[0108] 24 First Shape

[0109] 26 First contact position

[0110] 28 Second Shape

[0111] 30 Second contact position

[0112] 32 External dimensions

[0113] 34 sockets

[0114] 36 openings

[0115] 38 Axial end of contact element

[0116] 40 Radial spring bent into a ring

[0117] 42 crown spring

[0118] 44 shielding sleeve

[0119] 46 contact pins

[0120] 48 crimp plug

[0121] 50 crimp socket

[0122] 52Plugins for fixtures

[0123] 54 ring

[0124] 56 Inner contour

[0125] 58 Axial end of crown spring

[0126] 60 ring segments

[0127] 62 Circumferential direction

[0128] 64 Longitudinal axis of crown spring

[0129] 66 radial direction outward

[0130] 68 shielding sleeve body

[0131] 70 tongue piece

[0132] 71 Section of shielding sleeve

[0133] 72 Axial end of contact pin

[0134] 74 Press-fit section

[0135] 76 base part

[0136] 78 longitudinal axis of contact pin

[0137] 80 groups

[0138] 82 bridge

[0139] 84 first contact element

[0140] 86 Second contact element

[0141] 88 Segment manufactured in first configuration

[0142] 90 Segment manufactured in second configuration

[0143] 92 contact assembly

[0144] 94 longitudinal axis of mating contact

[0145] 96 Contact force

[0146] 98 Outer side of mating contact

[0147] 100 contact surface

[0148] 102 First expected operating state

[0149] 104 Second expected operating state

[0150] 106 crimping wings

[0151] 108 crimping socket inside

[0152] 110 The inner side of the mating contact.

Claims

1. An electrical contact element (1) for mating with a mating contact (20), The contact element (1) has at least one resiliently deflectable spring element (14), the spring element (14) having at least one contact point (18) for contacting the mating contact (20) and being designed to generate a contact force (96) acting on the mating contact (20) during operation, at least one section (22) made of a shape memory material, which is integrated into the at least one contact element (1) and can be transformed from a first shape (24) into a second shape (28) depending on temperature, in, The at least one contact point (18) of the contact element (1) in a stress-free state (2) is in a first contact position (26) in a first shape (24) of the section (22) made of shape memory material, and in a second contact position (30) in a second shape (28) of the section (22) made of shape memory material (22).

2. The contact element (1) according to claim 1, in, At least one of the at least one sections (22) made of shape memory material has a one-way memory effect.

3. The contact element (1) according to claim 1 or 2, in, At least one of the at least one sections (22) made of shape memory material has a two-way memory effect.

4. The contact element (1) according to any one of claims 1 to 3, in, The contact element (1) has a socket (34) for inserting the mating contact (20), and the at least one spring element (14) in the second shape (28) moves towards the socket (34) relative to the first shape (24).

5. The contact element (1) according to any one of claims 1 to 4, in, The outer dimensions (32) of the contact element (1) in the first shape (24) are smaller than the outer dimensions in the second shape (28).

6. The contact element (1) according to any one of claims 1 to 5, wherein: The at least one spring element (14) is formed by a tongue (70) punched out of the remaining contact element (1).

7. The contact element (1) according to any one of claims 1 to 6, wherein: The contact element (1) is configured to automatically deform from the first shape (24) to the second shape (28) when a current flowing through the contact element (1) exceeds a predetermined minimum value.

8. The contact element (1) according to any one of claims 1 to 7, wherein: The contact element (1) is a contact element (1) from the following group of contact elements (1): - a radial spring bent into a ring (40); - a crown spring (42); - a shielding sleeve (44); - a contact pin (46); - a crimping plug (48) or a crimping socket (50); A clamp (4) or an insert (52) for a clamp (4).

9. A contact assembly (92) comprising a contact element (1) according to any one of claims 1 to 8 and a mating contact (20) mating with the contact element (1), wherein: A contact force (96) exerted by the contact element (1) on the mating contact (20) is smaller in the first shape (24) than in the second shape (28).

10. The contact assembly (92) of claim 9, wherein: In the first shape (24), the area of ​​the contact surface (100) where the contact element (1) and the mating contact (20) come into contact is smaller than that in the second shape (28).

11. The contact assembly (92) according to claim 9 or 10, in, The contact assembly (92) has a first intended operating state (102) for conducting current between the contact element (1) and the mating contact (20) and a second intended operating state (104) for conducting current between the contact element (1) and the mating contact (20), wherein when the contact element (1) is in the first shape (24), the contact assembly (92) is in the first operating state (102), and when the contact element (1) is in the second shape (28), the contact assembly (92) is in the second operating state (104).

12. A group (80) comprising a plurality of contact elements (1) according to any one of claims 1 to 8, in, The set (80) includes a first contact element (84) having a section (88) made of a shape memory material in a first configuration, and a second contact element (86) having a section (90) made of a shape memory material in a second configuration different from the first configuration, Therein, apart from the shape memory material sections (80, 90), the first contact element (84) and the second contact element (86) have the same design.

13. A method for automatically fixing an electrical contact assembly (92), the electrical contact assembly (92) having a contact element (1) and a mating contact (20) mating with the contact element (1), in, The contact element (1) has at least one section (22) made of shape memory material, and when the temperature increases due to vibrations and / or current flow between the contact element (1) and the mating contact (20), the at least one section (22) automatically deforms from a first shape (24) to a second shape (28), wherein the contact force (96) applied by the contact element (1) on the mating contact (20) is lower in the first shape (24) than in the second shape (28).

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