Spring contact pin

Abstract

The invention relates to a spring contact pin (1) for the electrically conductive contact of a contact partner, comprising a sleeve-shaped housing (2) and a contact element (3) mounted in the housing (2) in a longitudinally displaceable manner, the contact element (3) having a piston (6) located at least in some regions in the housing (2) and a contact head (4) located outside the housing (2) and having a contact surface (5) for the contact partner, wherein a spring element (14), in particular a coil spring, is arranged in the housing (2), the spring element (14) being arranged in such a way that the contact element (3) can be elastically pressed into the housing (2). According to the invention, the piston (6) is designed as a hollow piston in a tubular manner, and the contact surface (5) of the contact head (4) is designed in a closed manner.

Description

Field of the Invention

[0001] The present invention relates to a spring contact pin for electrically contacting a contact mating part, having a sleeve-shaped housing and a contact element longitudinally movably supported in the housing, the spring contact pin having a piston at least partially located in the housing and a contact head outside the housing, the contact head having a contact surface for contacting the contact mating part, wherein a spring element, in particular a helical spring, is arranged in the housing in such a way that the contact element can be elastically inserted (einfedern) into the housing. Background Art

[0002] Such conventional spring contact pins are used, for example, for checking the functionality of electrical or electronic components, such as printed circuit boards or the like, wherein the spring contact pin prevents overloading of the contact site by being elastically inserted into the housing. If a plurality of spring contact pins are used side by side, all contact sites of the opposing contact mating parts can be reliably contacted, since the spring contact pins can optimally compensate for tolerances by elastic insertion of the respective contact elements. Therefore, spring contact pins are manufactured and used in large quantities. Here, the spring contact pins also suffer from mechanical wear, which occurs when the contact element is elastically inserted into the housing. In particular, when the piston is pushed into the housing against the force of the spring element, wear occurs due to friction between the contact elements (in particular the piston, the spring element and the housing) against each other. However, reliable and durable contact between the piston and the housing is advantageous for the electrical conductivity of the spring contact pin. These individual components of the spring contact pin are generally constructed to be electrically conductive and optionally provided with an electrically conductive coating in order to provide the lowest possible resistance. The mechanical and electrical functions or malfunction functions can affect each other here. Wear of the mechanical structure is also always associated with damage to the surface and its possible coating or hardening (such as in the form of a noble metalization). This results in a loss of contact performance and an increase in resistance. In addition, wear particles accumulate, which damage the mechanical and electrical functions. In order to avoid tribocorrosion, it is known, for example, to provide a protective layer on the contact site or to introduce a lubricant, for example. Summary of the Invention

[0003] It is an object of the present invention to provide an improved spring contact pin which has a longer service life than known spring contact pins by reduced wear without affecting the electrical conductivity here.

[0004] The object of the present invention is achieved by a spring contact pin having the features of claim 1. This has the advantage that the wear of the spring contact pin is reduced by simple structural measures without adversely affecting the electrical conductivity of the spring contact pin and thus its functional ability, and on the contrary, the electrical conductivity is increased by constructing the spring contact pin according to the invention.

[0005] According to the present invention, this is achieved in such a way that the piston is constructed in a tubular manner as a hollow piston, and the contact surface of the contact head is constructed as a closed structure. By constructing the piston as a hollow piston, that is, the piston is constructed in a tubular or sleeve shape, the mass of the contact element is reduced, so that the mass to be moved during the conversion process is also reduced accordingly. Thereby, the spring element can be designed with a reduced spring force, thereby reducing the force acting on the spring contact pin during the contact process. This also reduces the contact force and thus reduces the wear in the spring contact pin. Thus, the above advantages are achieved. By constructing the contact head or its contact surface in a closed manner, the tubular construction of the piston does not cause any adverse effects when contacting the contact mating part. In the overall tubular construction of the contact element, the contact head is always provided with an opening that is generated during the forming of the contact element for constructing the contact head. By adopting a closed construction, the structural accuracy of the contact element or the spring contact pin itself can be significantly improved, and a reliable electrical contact or a reliable conductive connection is always established.

[0006] Preferably, the contact head is constructed as a solid element or a solid body, that is, it does not have a cavity. In addition, the contact head according to the present invention has a plug section that is axially inserted into the piston. Through this two-piece construction of the contact element, the tubular piston can be manufactured independently of the contact head. This provides advantages both in terms of the manufacturing method and in terms of the variability of the construction of the contact element. Therefore, a plurality of different contact heads can be connected to one and the same piston. Thus, in particular, a spring contact pin system is provided that has a plurality of pistons and contact heads, wherein at least two of the contact heads are constructed differently. Thereby, a person skilled in the art can select between suitable contact heads during assembly, for example, according to the contact mating part to be contacted or other boundary conditions.

[0007] The piston is preferably constructed as a deep-drawn part. Due to the two-piece construction of the contact element, it is possible to also use the well-known technology of deep drawing for the piston. The deep drawing process itself is known and has been verified for decades in similar cases of forming parts. By the deep drawing process, particularly narrow tolerances can be selected, which ensure an improved interaction between the contact element, especially the piston, and the housing. In addition, by constructing the hollow piston, especially in the form of a deep-drawn part, the wall of the hollow piston can be constructed very thin without causing a critical loss in the stability or load-bearing capacity of the contact element. Therefore, compared with a solid piston, the material usage of this structure is reduced several times.

[0008] Furthermore, it is preferably provided that, in order to electrically and mechanically connect to the piston, the plug section is held in / on the piston in a force-fitting, form-fitting, and / or material-bonding manner. Thus, the piston and the contact head are firmly connected to each other, so that even during operation or during the test process, the reliable engagement of the spring contact pin, especially the contact element, is ensured.

[0009] Particularly preferably, the plug section is held in / on the piston by pressing, flanging, crimping, fusion welding and / or soldering. This results in a permanently secure connection between the piston and the contact head with advantageous electrical conductivity.

[0010] According to a preferred refinement of the invention, the piston has a cross-sectional narrowing between its ends, wherein the spring element extends into the piston and is axially supported on the one hand on the cross-sectional narrowing and on the other hand on the end of the housing facing away from the piston. Thus, the spring element is axially preloaded between the end of the housing and the piston, wherein the spring element is supported on the cross-sectional narrowing of the piston for this purpose. The cross-sectional narrowing is not located on one of the ends, but between the ends of the piston, so that the spring element extends into the piston, wherein the tubular shape of the piston enables easy accommodation of the spring element. The advantage of the local arrangement of the spring element inside the piston is that the individual parts of the spring element are not guided by the housing, but only by the piston. Thereby, wear or friction is not generated on these parts of the spring element in the interaction with the housing either. Thereby, the housing contact area that would otherwise come into contact during the movement of the piston can also be effectively protected against excessive wear.

[0011] Furthermore, it is preferably provided that the cross-sectional narrowing of the piston is arranged closer to the head than the end of the piston facing the housing end in terms of the axial extension. This results in that, when viewed in the axial extension direction, a part of the spring element is guided into the piston along its axial extension, thereby reducing wear. Here, the spring force is not affected.

[0012] Preferably, the spring element has at least one rigid spring element section. Elastic deformation of the spring element during contact is avoided in the rigid spring element section. In this regard, the rigid spring element section is understood as a section of the spring element in its longitudinal extension, in which section compression along the longitudinal extension is not possible or hardly possible. Furthermore, deformation transverse to the longitudinal extension is at least substantially prevented by the rigid construction, so that the spring element does not bend or flex laterally either in the rigid spring element section. Thus, a region of the spring element is defined by the rigid spring element section, which region does not exert a spring force on the one hand during inspection and on the other hand prevents deformation of the spring element. By advantageously placing the rigid spring element section, for example, wear in the region where the spring element transitions from the housing to the contact piston can be reduced.

[0013] Preferably, the rigid spring element section is at least substantially located between the piston and the housing end. At least in the non-operating state of the spring contact pin, when observed over the longitudinal extent of the spring element, the rigid spring element section is completely located between the piston and the housing end. Thereby, elastic pressing-in is achieved and ensured by the elastic element section, which is especially retained within the housing. By placing the rigid spring element section outside the piston or at least substantially outside the piston, the following effect is achieved: the spring element is deformed there in a manner that reduces or avoids contact (especially frictional contact) between the spring element and the housing or the inner wall of the housing. The larger the spring element section of the spring element within the piston, the lower the overall wear of the spring contact pin. Here, the outer diameter of the rigid spring element section is preferably smaller than the inner diameter of the housing, such that contact, especially frictional contact, between the rigid spring element section and the housing is avoided. Thereby, frictional contact of the spring contact pin is especially limited to the interaction between the housing and the piston.

[0014] Preferably, the piston has an inlet ramp for the spring element at its end facing the housing. Thereby, the accommodation of the elastic element into the piston over its longitudinal extent is simplified during elastic pressing-in. Herein, wear is especially prevented, and especially jamming or tilting of the spring element on the end side of the piston facing the housing end is also prevented. More precisely, by means of the inlet ramp, the spring element can be centered or introduced into the piston.

[0015] Furthermore, it is preferably provided that the housing end of the housing forms an axial stop for the spring element via plastic deformation, especially bending. Through the advantageous configuration of the housing end, simple assembly of the spring contact pin can be achieved. Especially during assembly, the housing end is not yet bent, so that the contact element can be pushed in or inserted into the housing from the rear, i.e., through the housing end. Subsequently, the housing end is plastically deformed in order to provide an axial stop for the spring element and in order to prevent the piston from being pushed out of the housing in the direction of the housing end. Herein, a reliable, space-saving and easily assembled structural improvement can be achieved in a simple and cost-effective manner.

[0016] According to a preferred refinement of the invention, the housing has a cross-sectional narrowing forming a step at its end facing away from the housing end, wherein the step is configured as an axial stop for the piston, which axial stop resists the force of the spring element. Thus, the piston is longitudinally movably held between the spring element supported on the housing end and the axial stop. Thus, the piston is also not pushed out by the spring element on the side of the housing facing away from the housing end by the spring element. Through this simple configuration, the spring contact pin is cost-effective and less prone to failure.

[0017] In particular, the cross-sectional narrowing of the housing is manufactured by a deep-drawing process. In particular, the housing as a whole is manufactured by a deep-drawing process. Thereby, the housing can be mass-produced in a simple and precise manner.

[0018] According to a preferred refinement of the invention, the length of at least the distance of the piston located in the housing is equal to the length of the housing minus the maximum allowable spring travel of the spring element and minus a predeterminable tolerance value. Thus, the piston extends almost completely through the housing. Since the spring element extends inside the piston, this has no adverse effect on the spring travel. However, due to the piston being constructed longer compared to the housing, an improved support of the piston in the housing is ensured, and at the same time the electrical connection between the housing and the piston is improved. Since the spring travel and the predeterminable tolerance value are taken into account when defining the length of the piston, it is ensured that the desired minimum or maximum spring travel is always achieved.

[0019] The end of the spring element facing the housing is preferably widened. Thereby, an improved support of the spring element on the housing end is provided. In particular, the housing end is post-deformed by a deformation process for constructing an axial stop as described before, whereby an opening is retained in the housing end. The wider the spring element is constructed at the location where it is supported on the housing end, the less likely it is for the spring element to enter the opening and get stuck therein and / or be jammed therein. Thus, the widening of the spring element results in an improved support.

[0020] Furthermore, it is preferably provided that the spring element has a longitudinal section outside the piston, and the outer diameter of the spring element widens in the direction of the housing end along this longitudinal section, so that the spring element abuts against the inner wall of the housing outside the piston. In this case, the spring element is radially guided through the piston inside the piston and is radially guided through the housing outside the piston, thereby ensuring a particularly reliable, bending-preventing guidance of the spring element. However, the wear between the spring element and the housing still increases.

[0021] Therefore, according to an alternative embodiment of the invention, this longitudinal section is particularly preferably constructed as a rigid spring element section. Thus, the rigid spring element section is located outside the piston. Since the spring element section is constructed as rigid, no relative movement occurs between the spring element section or the coils of the helical spring and the housing during the spring compression process. Instead, the spring mainly remains in the piston and less or not in the housing. The spring function is particularly ensured by the section of the spring element located inside the piston. In addition, the advantage resulting therefrom is that lateral bending or kinking of the elastic element is prevented. Preferably, the rigid spring element section is formed in such a way that the coils of the helical spring abut against each other axially, thereby preventing compression in the axial direction, because the abutting coils act as a continuous rod.

[0022] According to a preferred refinement of the invention, the piston has a cross-section narrowing at its end facing the housing, on which the spring element is supported. Different from the cross-section narrowing between the two ends of the piston, according to this embodiment, the spring element does not extend into the piston. Although the spring contact pin still has advantages in terms of weight reduction, spring force reduction, and wear reduction between the piston and the housing, since the elastically deformable part of the spring element is located outside the piston, slightly increased wear will occur. Nevertheless, the spring element can thus be manufactured at lower cost, because for example the length of the spring element can be reduced compared to the aforementioned embodiment.

[0023] According to this embodiment, the cross-section narrowing preferably has a centering inclined surface for centering the spring element between the piston and the housing. Thus, the spring element is centered or clamped radially between the piston and the housing, ensuring reliable guidance of the spring element and the piston in the housing. The centering inclined surface particularly has an inner diameter smaller than the inner diameter of the spring element, so that the centering inclined surface can be partially introduced into the spring element.

[0024] Furthermore, it is preferably provided that the spring element has a diameter narrowing at its end facing the piston to center the spring element on the piston. Thus, according to an alternative embodiment, the spring element partially enters into the piston in order to be centered therein. The above-mentioned advantages regarding centering are thereby obtained. Description of the Drawings

[0025] Other advantages and preferred features and combinations of features particularly result from the previous description and from the claims. The invention will be explained in detail below with the aid of the drawings. For this purpose, it is shown:

[0026] Figures 1A to 1E A first embodiment of an advantageous spring contact pin is shown,

[0027] Figure 2 A second embodiment of the spring contact pin is shown,

[0028] Figure 3A and Figure 3B A third embodiment of the spring contact pin is shown,

[0029] Figure 4 A fourth embodiment of the spring contact pin is shown,

[0030] Figure 5 A fifth embodiment of the spring contact pin is shown,

[0031] Figure 6 A sixth embodiment of the spring contact pin is shown,

[0032] Figure 7Shows a seventh embodiment of a spring contact pin,

[0033] Figure 8 shows an eighth embodiment of a spring contact pin, and

[0034] Figure 9A and Figure 9B show a ninth embodiment of a spring contact pin in simplified longitudinal sectional views, respectively. Detailed Description

[0035] Figure 1A Shows in a simplified longitudinal sectional view a favorable spring contact pin 1 having a sleeve-shaped housing 2 also referred to as a shell and a contact element 3 longitudinally movably supported in the housing 2. The contact element 3 has a contact head 4 with a closed contact surface 5 on the end side, which contact surface 5 is configured for electrically contacting a contact mating part by contact. For this purpose, the contact head 4 is manufactured as a solid element or solid body (i.e., without cavities), such that the contact surface 5 is also configured in a closed manner. According to this embodiment, the contact surface 5 is configured as spherical. In principle, the contact surface 5 can also have other shapes, such as concave, pointed, conical, star-shaped or fork-shaped.

[0036] Furthermore, the contact element 3 has a piston 6 which is fixedly connected to the contact head 4. The piston 6 is configured as a hollow piston and is configured as tubular for this purpose. Thus, the piston 6 is also configured as sleeve-shaped and has only a thin wall, wherein the wall of the piston 6 is preferably thinner than the wall of the sleeve-shaped housing 2. As Figure 1A shown, the piston 6 extends far into the housing 2 such that the piston extends at least over half of the longitudinal extent of the housing and preferably extends beyond this extent. Here, the piston 6 has a section 7 facing the contact head 4 and a section 8 assigned to the housing, wherein the section 8 is completely located inside the housing 2 and the section 7 projects from the housing at least in the unoperated state.

[0037] Figure 1B Shows an enlarged view of the spring contact pin 1 in the region of the spring contact pin 1 where the piston 6 enters the housing 2. The housing 2 is configured to be open at its end facing the contact head 4 and has a cross-sectional narrowing 9. Here, this cross-sectional narrowing 9 is achieved by a flange 10 of the housing 2.

[0038] The piston 6 also has a cross-sectional narrowing 11 over its longitudinal extent, such that the section 7 has a smaller outer diameter than the section 8 of the piston 6. Due to the cross-sectional narrowing 11 and the consequent different outer diameters of the piston 6, a step is produced in the piston 6, which forms an axial stop 12. Here, the outer diameter of the section 8 is greater than the inner diameter of the cross-sectional narrowing 9 of the housing 2, such that the axial stop 12 interacts in a form-fitting manner with the cross-sectional narrowing 9 in the direction of the contact head 4, thereby preventing the piston 6 from moving out of the housing 2 in the direction of the contact head 4.

[0039] According to this embodiment, as Figure 1A shown, the contact head 4 is configured as an element separate from the contact piston 6. To this end, the contact head 4 has a plug section 13 that is inserted into the section 7 of the piston 6. The plug section 13 and the section 7 are in particular always the same and are configured to match or be compatible with each other. In particular, the plug section 13 is axially pressed into the piston 6 such that the contact head 4 is held on the piston 6 by an interference fit. Optionally, the contact head 4 is additionally connected to the piston 6 by welding, brazing or form-fittingly, for example by flanging or deformation. By means of the two-piece construction of the piston with the separate contact head 4 and piston 6, it is ensured that the spring contact pin can be simply adapted to different boundary conditions and / or contact mating parts. Thus, contact heads 4 with different contact surfaces 5, in particular differently shaped contact surfaces 5, can be provided, and the contact heads 4 can be connected to the piston 6. The assembly of the selected contact head 4 with the piston 6 is preferably effected when the piston 6 has already been assembled in the housing 2. Alternatively, the assembly is carried out before the piston 6 is assembled in the housing 2. In a system of spring contact pins or contact elements having a plurality of pistons 6 and contact heads 4, in particular, the pistons 6 are identically configured and a plurality of different contact heads 4 are provided, such that by combining a specific contact head 4 with one of the pistons 6, the desired spring contact pin can be manufactured at low cost. Alternatively or additionally, a plurality of pre-assembled pin assemblies are provided, each of which consists of a piston 6 and a contact head 4 that has already been fixed thereto, where the contact heads can be configured identically or differently.

[0040] The spring contact pin 1 further has a spring element 14 in the form of a helical spring. The preloading of the helical spring 14 between the housing 2 and the contact element 3 causes the helical spring 14 to press the contact element 3 together with the contact head 4 out of the housing 2, or to press the axial stop 12 against the cross-section narrowing 11 of the housing 2. For this purpose, one end of the spring element 14 is supported on the housing end 15 of the housing 2 facing away from the contact head 4. The spring element 14 is supported at its other end on the contact element 3, in particular on the piston 6. For this purpose, according to the present embodiment, it is provided that the outer diameter of the spring element 14 is smaller than the inner diameter of the contact piston 6, so that the spring element 14 extends into the piston 6. In particular, the cross-section narrowing 11 forms an axial stop 16 for the spring element 14, so that the spring element 14 is axially supported on the inner side of the piston 6 on the cross-section narrowing 11. Thus, in the unoperated or elastically pressed-in state, as in Figure 1B shown, the spring element 14 extends over almost the entire length of the housing 2 and over the entire length of the section 8 of the piston 6.

[0041] Figure 1C An enlarged detail view of the spring contact pin 1 in the region of the housing end 15 is shown. The spring element 14 preferably has two longitudinally different sections. According to the present embodiment, the longitudinal section 14_1 located inside the piston 6 in the unoperated state is configured to be elastically or elastically deformable. The longitudinal section 14_2 located outside the piston 6 is rigidly configured so that the piston cannot be elastically pressed in. This is exemplified in Figure 1A and Figure 1C by the helical turns of the helical spring abutting each other in the longitudinal section 14_2, while the helical turns in the longitudinal section 14_1 are arranged axially spaced apart from each other and thus allow axial elastic pressing in.

[0042] By configuring the longitudinal section 14_2 of the spring element 14 protruding from the piston 6 to be rigid, no movement and no radial contact occur between the longitudinal section 14_2 and the inner side of the housing 2 during the elastic pressing-in of the contact element 3 during the inspection process, and thus no friction and wear occur. The elastic pressing-in only occurs inside the piston 6. This has the advantage that, on the one hand, the wear of the spring contact pin 1 is generally reduced and wear is prevented in particular in the region of the electrically conductive contact site between the piston 6 and the housing 2 by the spring element 14. During operation, only the piston 6 and the housing 2 rub against each other, thereby generally reducing wear and thus generally increasing the service life of the spring contact pin 1. By extending the spring element 14 into the piston 6 and axially supporting it there, a particularly long guide surface between the piston 6 and the housing 2 is ensured, which ensures precise guidance of the contact element 3 with little friction. In addition, a reliable electrical connection between the housing 2 and the contact element 3 is ensured by the long contact surface.

[0043] Figure 1D shows the spring contact pin 1 in the elastically pressed-in state, i.e., when the contact element 3 is elastically pressed into the housing 2 against the force of the spring element 14. Here, the spring travel is defined either by the spring element 14 itself or by the length of the piston 6, which abuts against the housing end 15 of the housing 2. Due to the rigid construction of the longitudinal section 14_2, this longitudinal section extends partially or mostly into the piston 6 depending on the length of the piston 6 construction and the length enabling the movement travel, such that the longitudinal section 14_1 is completely inside the piston and is compressed there, as shown in Figure 1B as shown.

[0044] Figure 1E shows an enlarged view of the spring contact pin 1 in the elastically pressed-in state in the region of the housing end 15. The piston 6 has an inlet bevel 17 for the spring element 14 at the free end of the section 8. Thus, during elastic pressing-in, the spring element 14 is advantageously introduced into the piston 6, reliably preventing the piston 6 from jamming on the spring element 14 or otherwise getting stuck.

[0045] Due to the advantageous construction of the elastic contact pin 1, a significantly narrower guiding gap is achieved by the combination of two deep-drawn parts (piston 6 and housing 2) inserted into each other acting as a sliding guide, because deep-drawn parts have an accuracy improvement factor of about 3 in terms of the actually achievable diameter tolerance compared to turned parts. Thus, the effective contact area between the piston 6 and the housing 2 is significantly increased, reducing the surface pressure and thus directly reducing frictional wear. The overall material usage is reduced several times, in particular, the weight to be moved of the contact element 3 is reduced and the material cost is reduced. Since the contact head 4 and the piston 6 are constructed as separate elements, there is especially the advantage that the coating thicknesses of the two parts can be set independently of each other, and likewise, for example, the coating material and the coating technique can be set independently of each other. The base materials can also be selected and used independently of each other. Here, non-conventional manufacturing techniques can also be implemented, especially for the manufacturing of the contact head 4, and relatedly, new head shapes can be achieved.

[0046] The residual wear caused by the spring element 14 inside the piston 6 is not likely to cause interference because it does not affect the electrical function of the spring contact pin 1, especially the contact surface function. Therefore, although there is still some wear, this wear is separated from the important functional areas or contact areas between the housing 2 and the piston 6. Avoidance of wear in a conventional spring contact pin is also achieved by a favorable construction, in which the spring element is pre-tensioned relative to the free end of the piston. In addition, in a conventional design, wear also occurs in the functionally important guiding areas of the piston 6 and the housing 2 and remains there. Since the wear is now transferred into the piston 6 by the spring element 14 extending into the piston 6, the wear also remains essentially within the piston 6 and does not or does not reach the contact site between the piston 6 and the housing 2 as quickly, whereby the service life of the spring contact pin 1 is further increased. In addition, the rigid longitudinal section 14_2 of the spring element 14 results in fewer transverse forces acting on the piston 6, whereby the service life of the spring contact pin is further increased by reducing the frictional force.

[0047] Advantageously, the piston 6 and the housing 2 have favorable coatings for increasing the conductivity and / or for reducing wear. Here, the coating can be, for example, an electroplated noble metal metallization or the like.

[0048] Figure 2 A second embodiment of the spring contact pin 1 is shown, which differs from the first embodiment in that the spring element 14 does not have a constant diameter as in the previous embodiment. Instead, as shown in Figure 2 the diameter of the spring element 14, or the helical spring, widens towards the housing end 15, so that the spring element 14 is constructed wider at its end facing the housing end 15. Thereby, even if the housing end has a remaining opening 18, especially determined by manufacturing, as shown in this embodiment, it is ensured that the spring element 14 reliably, especially axially centered, abuts against the housing end 15. The housing 2 and the piston 6 are both advantageously constructed as deep-drawn parts. Thereby, in particular, different cross-sections or diameters of the piston 6 in the sections 7 and 8 can be achieved in a favorable manner. Thereby, the housing 2 can also be manufactured cost-effectively and precisely. According to the first two embodiments, the housing end 15 has been deformed by the deep-drawing process such that it forms an axial stop for the spring element 14. Then, the flanging 10 is manufactured to form a cross-section narrowing 9 at the opposite end.

[0049] According to an alternative embodiment, as shown in Figure 3A and Figure 4 B, in the deep-drawing process, the cross-section narrowing 9 is manufactured in a stepped shape. The housing end 15 is open or constructed without a narrowing after the deep-drawing process, as shown in Figure 3A Therefore, now the contact element 3 is inserted from the side of the housing end 15, such as byFigure 3A is first axially pushed in as shown by arrow 19 in the section 7. Immediately thereafter or simultaneously, the spring element 14 is introduced or pushed into the housing 2 starting from the housing end 15. Immediately thereafter, the housing end 15 is plastically deformed so that the cross-section of the housing 2 narrows or decreases at the housing end 15, as shown in Figure 3B . For this purpose, the end is bent inwards, as shown by arrow 20 in Figure 3A and Figure 3B . In particular, flanging is involved here. The deformation preferably lies on or near the housing end so that as little structural space length as possible is lost. Immediately thereafter, the piston 6 is positively held in the housing 2 by means of the spring element 14 against loss. For final assembly, the contact head 4 is subsequently also assembled on the piston 6. If the outer diameter of the contact head 4 is only as large as the outer diameter of the piston 6 in the section 7, then the contact head 4 can also be assembled on the piston 6 before the piston 6 is assembled in the housing 2 and can move through the housing 2 together with the piston 6.

[0050] Figure 4 Another fourth embodiment of the spring contact pin 1 is shown in an enlarged longitudinal sectional view. The difference between this embodiment and the foregoing embodiment is that the rigid longitudinal section 14_2 is not arranged at the end of the spring element 14, but is constructed (viewed along the longitudinal extent of the spring element 14) between two elastic longitudinal sections 14_1 and 14_2. Here, the rigid longitudinal section 14_2 is in a region in the non-operated state of the spring contact pin 1 in which the spring element 14 enters the piston 6. Thereby, the spring element 14 is reinforced in the transition region, so that the spring element is prevented from skewing or tipping when the piston 6 is elastically pressed in and thus when pushed onto the spring element 14. Since the subsequent elastic longitudinal section 14_3 leading to the housing end 15 is also compressible or elastically deformable, the spring travel is increased compared to the above embodiment and the spring element 14 is matched to the inner diameter of the housing 2.

[0051] Figure 5 A fifth embodiment of the spring contact pin 1 is shown, which differs from the foregoing embodiment in that the rigid longitudinal section 14_2 is completely located within the section 8 of the piston 6 in the elastically decoupled state or non-operated state of the spring contact pin 1. Therefore, compared to the embodiment of FIG. 1, the rigid longitudinal section and the elastic longitudinal section of the spring element 14 are exchanged. Here, it is preferably provided that the diameter of the spring element 14 increases in the elastic section so that the spring element 14 radially abuts against the inner side of the housing 2 in the elastic region in order to be optimally guided there.

[0052] Preferably, at least in Figures 4 to 6In the embodiment, the diameter change of the spring element 14 is achieved by means of a tapered transition length section respectively. Thereby, the sudden mechanical stress in the spring element 14 is reduced. Furthermore, preferably, the first contact point of the spring element 14 on the housing 2 is axially further away from the piston guide device. Thereby, the wear area is shortened.

[0053] Figure 6 The sixth embodiment of the spring contact pin 1 is shown, which is different from the foregoing embodiments in that the spring element 14 does not have a rigid longitudinal section. However, as shown in the fifth embodiment, the spring element 14 has a diameter widening in the longitudinal section of the spring element 14, and this longitudinal section is radially guided in the housing 2. Here, the widening of the diameter is axially spaced from the piston 6, so that when the contact element 3 is elastically pressed in, other regions of the longitudinal section of the spring element 14 with a reduced diameter can first enter into the piston 6.

[0054] Figure 7 Another embodiment of the spring contact pin 1 is shown, which is different from the foregoing embodiments in that the spring element 14 is supported on the end of the piston 6 facing the housing end 15 and does not enter into the piston. For this purpose, the spring element 14 has a diameter reduction at its end facing the piston 6, so that only the end of the spring element 14 enters into the piston 6 and thereby centers the piston 6. The lead-in bevel 17 of the piston 6 acts concentrically on the spring element 14 and the piston 6 with the turns of the helical spring here.

[0055] Figure 8 The eighth embodiment of the spring contact pin 1 is shown, which is different from the foregoing embodiments in that the piston 6 has a diameter reduction, in particular a plastic deformation, at its end facing the housing end 15, similar to the diameter reduction of the housing end 15, wherein the helical spring 14 has a constant diameter, and the inner diameter of the narrowed portion at the piston end is configured to be smaller than the inner diameter of the spring element 14 of the helical spring. Thereby, the helical spring 14 is guided between the narrowed end 21 and the inner side of the housing 2 with its turns, and centering is also achieved thereby. However, here, the piston 6 enters into the spring element 14 instead of being otherwise hindered, such as in Figure 7 the embodiment.

[0056] Figure 9A and Figure 9B The ninth embodiment of the spring contact pin 1 is shown, in this regard, which corresponds to the embodiments of Figure 7 and Figure 8 , wherein the spring element 14 is supported on the end of the piston 6 facing the housing end 15. However, different from the foregoing embodiments, the spring element 14 is directly supported on the undeformed, flat end wall of the cylindrical section 8 of the piston 6, as shown in the detail view of Figure 9B .

Claims

1. A spring contact pin (1) for electrically contacting a contact mating part, having a sleeve-shaped housing (2) and a contact element (3) longitudinally displaceably supported in the housing (2), the contact element having a piston (6) at least partially located in the housing (2) and a contact head (4) located outside the housing (2) with a contact surface (5) for contacting the contact mating part, wherein, A spring element (14), in particular a helical spring, is arranged in the housing (2) in such a way that the contact element (3) can be elastically pressed into the housing (2), characterized in that the piston (6) is tubularly configured as a hollow piston and the contact surface (5) of the contact head (4) is configured in a closed manner.

2. The spring contact pin according to claim 1, wherein, The contact head (4) is configured as a solid body and has a plug section (13) axially inserted into the piston (6).

3. The spring contact pin according to any one of the preceding claims, characterized in that The piston (6) is configured as a deep-drawn part.

4. The spring contact pin according to any one of the preceding claims, characterized in that, The plug section (13) is held in the piston (6) in a force-fitting, form-fitting and / or material-fitting manner for electrical and mechanical connection to the piston (6).

5. The spring contact pin according to claim 3, wherein The plug section (13) is held in the piston (6) by pressing, flanging, crimping, fusion welding and / or soldering.

6. The spring contact pin according to any one of the preceding claims, characterized in that, The piston (6) has a cross-section narrowing (11) between its ends, and the spring element (14) extends into the piston (6) and is axially supported on the cross-section narrowing (11) on the one hand and on the housing end (15) on the other hand.

7. The spring contact pin according to any one of the preceding claims, characterized in that The cross-section narrowing (11) of the piston (6) is arranged closer to the contact head (4) than the end of the piston (6) facing the housing end (15) when observed over the axial extension of the piston (6).

8. The spring contact pin according to any one of the preceding claims, characterized in that, The spring element (14) has at least one rigid spring element section (14_2).

9. The spring contact pin according to any one of the preceding claims, characterized in that The rigid spring element section (14_2) is at least substantially located between the piston (6) and the housing end (15).

10. The spring contact pin according to any one of the preceding claims, characterized in that, The outer diameter of the rigid spring element section (14_2) is smaller than the inner diameter of the housing (2).

11. The spring contact pin according to any one of the preceding claims, characterized in that, The piston (6) has an inlet bevel (17) for the spring element (14) at its end facing the housing end (15).

12. The spring contact pin according to any one of the preceding claims, characterized in that, The housing end (15) is plastically deformed, in particular bent, to form an axial stop for the spring element (14).

13. The spring contact pin according to any one of the preceding claims, characterized in that, The housing (2) has a cross-section narrowing (9) forming a step at its end facing away from the housing end (15), wherein the step is configured as an axial stop (12) for the piston (6) against the force of the spring element (14).

14. The spring contact pin according to the preceding claim, characterized in that, The cross-section narrowing (9) of the housing (2) is formed by flanging or by a deep-drawing process.

15. The spring contact pin according to any one of the preceding claims, characterized in that, The length of at least the section of the piston (6) located in the housing (2) corresponds to the length of the housing (2) minus the maximum allowable spring travel of the spring element (14) and minus a predefined tolerance value.

16. The spring contact pin according to any one of the preceding claims, characterized in that, The end of the spring element (14) facing the housing end (15) is widened.

17. The spring contact pin according to any one of the preceding claims, characterized in that, The spring element (14) has a longitudinal section outside the piston (6), and the outer diameter of the spring element (14) widens along the longitudinal section in the direction of the housing end (15) such that the spring element (14) abuts against the inner side of the housing (2) outside the piston (6).

18. The spring contact pin according to any one of the preceding claims, characterized in that, The longitudinal section constitutes a rigid longitudinal section (14_2) of the spring element (14).

19. The spring contact pin according to any one of the preceding claims, characterized in that, The piston (6) has a cross-section narrowing (21) at its end facing the housing (2), and the spring element (14) is supported on the cross-section narrowing (21).

20. The spring contact pin according to claim 19, characterized in that, The cross-section narrowing (21) forms a centering inclined surface for centering the spring element (14) between the piston (6) and the housing (2).

21. The spring contact pin according to any one of the preceding claims, characterized in that, The spring element (14) has a diameter reduction (22) at its end facing the piston (6) to center the spring element (14) on the piston (6).

Images