Stem cap to ensure electrical busbar fixation and sealing

Abstract

A rod plug (10) for providing a connection between a first bus bar (4) and a second bus bar (5) in an electrical / electronic housing (66) and for sealing an orifice (60), the rod plug comprising a disc-shaped body (1) having a first axis, a rod (2) extending from a first end (21) adjacent to the body to a second end (22), the rod being extended by a finger (3) from the second end of the rod (22) to a free end (32), the finger being formed as a cylinder of round section, with a diameter smaller than a transverse dimension of the second end of the rod, forming a shoulder (7) at the second end of the rod, capable of pushing, directly or indirectly, the first electrical bus bar against the second electrical bus bar. Abstract figure: Fig. 3

Description

Title of the invention: Stem cap for ensuring electrical bus-bar fixing and sealing

[0001] The present invention generally relates to a stem cap for providing electrical bus bar attachment and sealing relative to an orifice.

[0002] The present invention also relates to an electrical and / or electronic box comprising a connection to be provided between two bus bars and a rod plug to provide the connection between the two bus bars and form a seal with respect to an orifice in the wall of the box.

[0003] We are particularly interested here in electrical and / or electronic boxes through which significant electrical power passes, which requires the installation of conductors called bus bars.

[0004] A busbar is a metal bar, preferably flat, made for example from aluminum or copper.

[0005] In an electrical and / or electronic box, to ensure the electrical power path between the exterior of the box and the interior of the box, use is made on the one hand of a first bus-bar which passes through the wall of the box and which is configured to be coupled to another element exterior to the box, and use is made on the other hand of a second electrical bus-bar internal to the box.

[0006] In this configuration, it is necessary to connect the first bus bar to the second bus bar inside the housing, in an area of ​​the housing where access from the outside can be provided via holes made on the wall of the housing.

[0007] According to a known solution, there is a hole in each of the first and second bus bars, and a screw passes through the two holes in question, this screw being screwed by a socket of a screwing tool which is located outside the housing, the socket coming through a specific orifice to approach and turn the screw in the area of ​​the bus bar holes inside the housing. Then the specific passage orifice for the socket must be sealed hermetically by a plug.

[0008] A large passage hole must therefore be provided for the screwdriver socket. In addition, there are often at least two electrical power paths to be provided and therefore the wall of the housing must have at least two large passage holes for the screwdriver socket.

[0009] In short, the assembly of the first and second bus bars requires two parts (screw and cap) and requires two operations, i.e. screwing and fitting the respective cap.

[0010] In this context, a need has emerged to offer a solution that is less expensive in terms of hardware and faster in terms of process time.

[0011] For this purpose, a rod plug is proposed for ensuring a connection between a first bus bar and a second bus bar in an electrical / electronic box and for ensuring sealing of an orifice provided in a wall of said box, the rod plug comprising: a disc-shaped body having a first axis, a rod (2) extending, parallel to the first axis, from a first end (21) adjacent to the body to a second end (22), the rod being extended by a finger (3) extending, in extension of the rod, from the second end of the rod to a free end, the finger being formed essentially as a cylinder of round or polygonal section, of diameter less than at least one transverse dimension of the second end of the rod, thus forming a shoulder at the second end of the rod, said shoulder being capable of pushing, directly or indirectly, the first bus-bar against the second bus-bar.

[0012] Thanks to these provisions, it is possible to avoid using a screwdriver-type tool to assemble the two bus bars together by screwing. In addition, a single part can provide two functions, i.e., on the one hand, the electrical connection between the two bus bars and, on the other hand, the watertight closure of the access hole to the connection of the bus bars.

[0013] It is noted that preferably the rod and the body can be coaxial, namely share the same axis. However, it is not excluded that the rod is not placed in the center of the disc.

[0014] Note that the disc shape of the body does not exclude the presence of a flat surface, as will be seen at the end of the description.

[0015] The term "ensuring a connection" must at least be understood to mean an electrical contact. Consequently, there must be a minimum contact pressure, and there may even be a strong connection with immobilization thanks to the finger which passes through the holes and which prevents any substantial relative movement of one bus bar relative to the other.

[0016] The bus bar is an electrical bus bar, which allows a current to flow with a high amperage. The bus bar is a flat elongated part with a generally rectangular cross section. The bus bar is made for example of aluminum or copper, or alloys of these metals. Such a bus bar is formed as a strip of metal with a hole at the location of its electrical connection to another part.

[0017] Before insertion of the rod plug, the two respective end portions of the bus bars are in a slight cantilever configuration, the insertion of the finger and the pushing of the rod cause the two bus bars to flex towards the inside of the housing, the resilience of the second bus bar may be greater than that of the first bus bar or well the second bus bar can have a stroke limited by another element. Consequently, the shoulder comes to exert a mechanical pressure which leads to ensuring an intimate electrical contact between the two bus bars.

[0018] Advantageously, as will be seen later, in the housing wall, the diameter of the orifice necessary for the placement of the proposed rod plug is smaller than the diameter necessary for the passage of the screwdriver socket.

[0019] According to one embodiment, the free end of the finger has a rounded, chamfered or conical tip.

[0020] As a result, insertion of the rod and finger into the holes is facilitated, even if the alignment is not perfect. Advantageously, insertion of the finger recenters the two holes and realigns the positions of the two busbar end portions.

[0021] According to one embodiment, the stem cap is made of synthetic plastic material, based on a polymer such as polyamide, polyethylene, or any other polymer suitable for the mechanical strength and electrical insulation requirements for this part.

[0022] According to one embodiment, the body comprises a peripheral edge with clipping lugs and a support collar.

[0023] The lugs retract when a user pushes the rod cap towards the inside of the electrical box. Said lugs return to their rest position after having passed the thickness of the wall edge and then anchor there, preventing the cap from returning backward.

[0024] According to one embodiment, there is provided, at the end of the rod, an elastic pressure device configured to clamp together at least the first and second bus bars.

[0025] The elastic pressure device may typically be a plastic pin, or a plastic elastic clip.

[0026] According to one embodiment, the pressurizing device comprises two tabs which embrace the two bus bars, and which each have an inclined distal portion capable of causing the device to move apart simultaneously with the insertion of the stem cap, before they return to a closed position in contact with the first and second bus bars, after passing beyond the second bus bar.

[0027] According to one embodiment, a spring and a support washer are provided, the spring being interposed between the shoulder and the support washer, the support washer being configured to press on the first bus bar.

[0028] This results in pressurization with well-calibrated pre-stressing.

[0029] According to one embodiment, the body comprises an annular groove open radially outwards in which an O-ring is arranged.

[0030] This provides effective sealing at the interface between the body of the plug and the orifice in the housing wall.

[0031] According to one embodiment, the body is provided on its outer peripheral edge with a screw thread configured to cooperate with a complementary screw thread provided in the orifice.

[0032] This results in well-calibrated pressure and good value for money. Note that the screwing function remains compatible with the presence of an O-ring.

[0033] According to one embodiment, the finger is equipped with a fir pin. Advantageously, the teeth of the fir pin are anchored behind the second bus bar. This provides an assembly by sandwiching between the shoulder and at least one pair of teeth of the fir pin. This solution offers excellent value for money.

[0034] The present invention also relates to an electrical / electronic box comprising at least a first bus bar with a first hole, a second bus bar with a second hole, the first and second holes being substantially coaxial, a casing with at least one orifice, preferably round, located opposite the first and second holes, and a stem cap as presented and defined above, the finger being inserted into the first hole and into the second hole, the shoulder directly or indirectly pressing the first bus bar against the second bus bar, and the body hermetically closing the orifice.

[0035] According to one embodiment, the orifice has an orifice diameter at most equal to three times the diameter of the finger.

[0036] This allows a significant reduction in the diameter of the holes, and a gain in size and weight of the electronic box.

[0037] We can typically have the diameter of the finger D3 = 6 mm.

[0038] The orifice diameter D6 can typically be between 12 and 14 mm, preferably less than 18 mm, whereas a diameter of at least 20 mm is generally required to fit a screwdriver socket capable of gripping an M6 screw with a hexagonal screw head.

[0039] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] illustrates in sectional view a first example of the production of a rod plug ensuring the connection between two bus bars and a seal at the level of the housing wall; - [Fig.2] illustrates in profile view the stem cap of [Fig.l]; - [Fig.3] illustrates in sectional view a second example of the production of a rod cap ensuring the connection between two bus bars and a seal at the level of the housing wall, with a cap screwing function; - [Fig.4] illustrates in sectional view a third example of the production of a rod cap ensuring the connection between two bus bars and a seal at the level of the housing wall, with a finger in the shape of a fir tree pin; - [Fig.5] illustrates in sectional view a fourth example of the production of a rod cap ensuring the connection between two bus bars and a seal at the level of the housing wall, with a pressure spring and a support washer; - [Fig.6] illustrates in sectional view a fifth example of the production of a rod cap ensuring the connection between two bus bars and a seal at the level of the housing wall, with an elastic clipping pin; - [Fig.7] illustrates in perspective view the stem cap of [Fig.l]; - [Fig.8] illustrates in top view a part of an electrical power box in an area where two pairs of bus bars are connected together by means of two plugs formed according to the present invention; - [Fig.9] illustrates in top view a particular example of an area where two pairs of bus bars are connected together by means of two plugs formed according to the fifth embodiment.

[0040] In the various figures, the same references designate identical or similar elements. For reasons of clarity of the description, certain elements are not necessarily represented to scale.

[0041] In [Fig.8] is shown a portion of electrical / electronic box 66 in which electrical power passes in the form of significant currents. Here in the example illustrated, there are two electrical paths, for example a positive path VI and a negative path V2.

[0042] One or more electrical / electronic boxes of this type may be found in an electric or hybrid vehicle.

[0043] The wall of the housing is marked 6. The housing can be made of aluminum alloy or even of high mechanical performance plastic material. The structural envelope of the housing is called the casing.

[0044] The first electrical path VI comprises a first internal bus bar 81 intended to be connected to a second bus bar 83 which passes through the wall 6 in a connector member 65.

[0045] The second electrical path V2 comprises a first internal bus bar 82 intended to be connected to a second bus bar 84 which passes through the wall 6 in the connector member 65.

[0046] The second electrical channel V2 illustrates a configuration where the end portions of the bus bars to be connected have axes which are not aligned, whereas the axes of the bus bars of the first channel V1 are aligned.

[0047] In [Fig.8], a stem plug according to the invention is inserted into the access orifice corresponding to the first electrical channel while it is not present in the access orifice 60 corresponding to the second electrical channel.

[0048] In [Fig. 1], a first bus bar 4 and a second bus bar 5 are shown, which correspond for example respectively to the first bus bar 81 and the second bus bar 83 discussed above with respect to [Fig. 8]. The first and second bus bars are shown in profile, their respective thicknesses E4 and E5 can be seen. Each end of the bus bar to be assembled is pierced with a hole. More precisely, the first bus bar 4 comprises a first hole 41 and the second bus bar 5 comprises a second hole 52.

[0049] The first hole 41 and the second hole 52 each have a diameter of 6 to 7 mm in the typical example presented.

[0050] The first bus bar 4 is the bus bar closest to the outside, i.e. the one that is encountered first by the stem of the plug. Depending on the circumstances, it may be either the internal bus bar or the external bus bar.

[0051] The second bus bar 5 is the bus bar furthest from the outside, i.e. the one encountered second by the stem of the plug. It can be either the internal bus bar or the external bus bar.

[0052] The second busbar 5 may be supported by a stop or its bending movement when pushed in response to insertion of the rod is limited by a stop-forming element or an elastic travel limit.

[0053] The width L4 is generally between 10 mm and 20 mm. The thicknesses E4 and E5 are generally between 2 mm and 5 mm.

[0054] In [Fig. 1], we find in section the wall 6 of the housing at the place where the orifice 60 is located. We note that an orifice edge 64 is provided in the casting of the housing which is thicker than the wall in the current section.

[0055] The orifice 60 is a round orifice, with an internal diameter D6. The axis of the orifice, called the first axis, is denoted A. D6 is generally between 12 mm and 20 mm. Preferably, D6 is less than 18 mm.

[0056] Turning to Figures 1, 2 and 7, the proposed stem cap, referenced 10, comprises a disc-shaped body 1 which is centered on the first axis A.

[0057] The dimension of the body along the axis A is noted Ll, it can be between 2 mm and 5 mm for example.

[0058] The body 1 comprises an annular groove 17 open radially outwards in which an O-ring 16 is arranged.

[0059] The body 1 comprises a peripheral edge with clipping lugs 9 and a support collar 8.

[0060] When the stem plug 10 is inserted into its position, i.e. from left to right in the figures, the lugs 9 flex as they pass the orifice rim 64 and the insertion movement continues and the plug advances until the collar 8 comes to bear on the outside of the orifice rim 64. The lugs 9 have then passed the opposite side of the orifice edge, they elastically return to their resting shape and thus lock the position of the body of the plug 1 relative to the wall 6.

[0061] The stem cap 10 comprises a stem 2 which extends from a first end 21 adjacent to the body 1 to a second end 22.

[0062] The rod 2 extends parallel to A, here the rod and the body are coaxial.

[0063] The dimension of the rod along the axis A is noted L2, it can be between 10 mm and 40 mm for example.

[0064] In the example illustrated, the rod 2 is of round section, but it could be of polygonal section. The diameter of the rod, denoted D2, can in practice be between 8 mm and 10 mm.

[0065] The rod is extended by a finger 3 which extends from the second end of the rod 22 to a free end 32 of the finger.

[0066] The diameter of the finger noted D3, can in practice be between 5 mm and 6 mm.

[0067] The dimension of the finger along the axis A is noted L3, we will see that this length depends strongly on the exemplary embodiments presented in the remainder of this disclosure.

[0068] Of course, the dimensions stated above must be adapted according to the diameter of the holes drilled in the bus bars.

[0069] The free end of the finger 32 has a rounded, chamfered or conical tip to facilitate insertion of the finger into the first and second holes 41, 52.

[0070] In the example illustrated, finger 3 is of round section, but it could be of polygonal section.

[0071] The finger 3 has a diameter smaller than at least one transverse dimension of the second end 22 of the rod 2, which forms a shoulder 7 at the second end of the rod.

[0072] In the first embodiment illustrated in Figures L 2 and 7, the rod plug 10 pushes against the two bus bars, each of which has a certain elasticity. More precisely, before the rod and its finger are inserted into the holes of the bus bars, the bus bars are at rest in a position closer to the orifice and the wall than after the insertion of the rod plug. In addition, the second bus bar 5 has a higher resilience than the first bus bar 4.

[0073] Therefore, when the stem plug 10 is inserted, the shoulder 7 pushes the two bus bars. The first bus bar 4 being more flexible than the second, this causes a positive pressure contact between the first bus bar 4 and the second bus bar 5.

[0074] The end of the finger 32 may protrude from the hole of the second bus bar, i.e. go beyond the thickness E5. Alternatively, the end of the finger 32 may remain below it, it is not necessary that it exceeds in the first embodiment.

[0075] The stem cap 10 is made of synthetic plastic material, based on a polymer such as polyamide, polyethylene, or any other polymer suitable for the mechanical strength and electrical insulation requirements for this part. The material in question may be loaded with fibers.

[0076] In a second embodiment illustrated in [Fig. 3], a screwing function of the body of the plug is provided relative to the thick edge 64' of the orifice 60 in the wall. For this purpose, a helical thread is provided on the radially outer peripheral edge of the body of the plug, which cooperates with opposite shapes, either a complementary helical thread in the orifice, or simple pins provided in the wall directed towards the axis of the edge 64'. The face pitch may correspond to 1 / 4 turn or 1 / 2 turn to carry out the necessary screwing.

[0077] A bayonet movement type kinematics is also not excluded.

[0078] Note that the O-ring 16 is placed on the inside relative to the helical thread.

[0079] It is noted that in this configuration, it is not necessary to have lugs or other clipping elements; it is the screwing function which ensures the final insertion movement and the mechanical retention of the body of the plug in the orifice 60.

[0080] It should be understood that anything not specifically commented on in the second exemplary embodiment should be considered identical or similar to what was presented for the first exemplary embodiment.

[0081] In a third embodiment illustrated in [Fig.4], a fir-tree pin 33 is provided at the end of the finger. In this configuration, the body of the plug is identical to what was presented for the first embodiment. On the other hand, the end of the finger differs because it must necessarily penetrate beyond the thickness of the second bus-bar with the harpoon shapes of the fir-tree pin which buttress on the inner side.

[0082] The fir-tree pin 33 comprises a plurality of teeth 37 arranged axially one behind the other so that the gripping function can adapt to several thicknesses. At least one of these teeth 37 is anchored behind the second bus bar.

[0083] The length L3 can typically be between 10 millimeters and 20 millimeters here.

[0084] It should be understood that anything not specifically commented on in the third exemplary embodiment should be considered identical or similar to what has been presented for the other exemplary embodiments already commented on.

[0085] In a fourth embodiment illustrated in [Fig.5], a spring pressure system is provided.

[0086] In this configuration, the body of the cap is identical to what has been presented for the first example of realization. On the other hand, the length of the rod here L20 is less than L2. In compensation, the length of the finger is greater.

[0087] A spring 34 and a support washer 35 are provided. The free end of the finger is provided with at least one hook 36.

[0088] The spring 34 is a metal helical type spring working in compression, it is mounted around the finger. The spring is interposed between the shoulder 7' and the support washer 35. The support washer 35 is supported on the first bus-bar 4 around the hole 41, it plays the role of the shoulder already seen in the first and second embodiments. The support washer 35 is a metal washer, very common and inexpensive just like the spring 34. The spring 34 support washer 35 are pre-assembled and cleverly held in place by the hooks 36, before assembly on the bus-bars.

[0089] The support pressure is well calibrated, it remains stable over time and in life, it is defined by the stiffness of the spring.

[0090] It is noted that the shoulder 7 of the rod here provides indirect support relative to the first bus-bar 4, which justifies the generically expressed expression “being capable of directly or indirectly pushing the first bus-bar 4 against the second bus-bar”.

[0091] Here too, the end of the finger penetrates beyond the thickness of the second and a hook / harpoon 36 is provided which is braced on the inner side behind the hole 52.

[0092] It should be understood that anything not specifically commented on in the fourth exemplary embodiment should be considered identical or similar to what has been presented for the other exemplary embodiments already commented on.

[0093] In a fifth embodiment illustrated in [Fig.6], a pressure clip 12 is provided.

[0094] The elastic pressure device may typically be a plastic pin, or a plastic elastic clip.

[0095] According to the illustrated embodiment, the pressurizing device comprises a base 19 fixed in a groove 74 provided between the rod and the finger. From this base extend two elastic tabs 15 which embrace the two bus bars.

[0096] Each leg 15 comprises a distal portion 13 inclined relative to the axis A (flared) capable of causing the device to move apart simultaneously with the insertion of the stem cap 10.

[0097] When the legs return to their closed position after the second busbar has passed, the bent portion 14 comes to bear behind the second busbar 5.

[0098] Generally any resilient pressurizing device configured to clamp together at least the first and second bus bars may be suitable.

[0099] This elastic clamp configuration is particularly suitable for the case where the axes bus bars to be connected are aligned.

[0100] Angular indexing of the pressurizing clip relative to the rod 2 and the finger 3 of the rod cap may be provided. For this purpose, the groove 74 may be provided with one or two flats which provide an indexing and anti-rotation function of the clamp relative to the rod.

[0101] Furthermore, similarly, as illustrated in [Fig.9], a flat 47 (or two) may be provided on the wall orifices, in order to impose a particular orientation of the plug at the time of insertion along the axis A.

Claims

Claims

1. A rod plug (10) for providing a connection between a first bus bar (4) and a second bus bar (5) in an electrical / electronic housing (66) and for sealing an orifice (60) provided in a wall (6) of said housing, the rod plug comprising a disc-shaped body (1) having a first axis (A), a rod (2) extending, parallel to the first axis, from a first end (21) adjacent to the body to a second end (22), the rod being extended by a finger (3) extending, as an extension of the rod, from the second end of the rod (22) to a free end (32), the finger being formed essentially as a cylinder of round or polygonal section, with a diameter smaller than at least one transverse dimension of the second end of the rod, thus forming a shoulder (7) at the second end of the rod, said shoulder being capable of pushing, directly or indirectly,the first busbar (4) against the second busbar.,

2. A stem cap according to claim 1, wherein the free end of the finger (32) has a rounded, chamfered or tapered tip.

3. A stem cap according to any one of claims 1 to 2, wherein the body comprises a peripheral rim with clipping lugs (9) and a support collar (8).

4. A stem cap according to any one of claims 1 to 3, wherein there is provided at the end of the stem an elastic pressure device configured to clamp together at least the first and second bus bars (4, 5).

5. A stem cap according to any one of claims 1 to 3, wherein a spring (34) and a support washer (35) are provided, the spring being interposed between the shoulder (7) and the support washer, the support washer being configured to press on the first busbar (4).

6. A stem cap according to any one of claims 1 to 5, wherein the body comprises an annular groove (17) open radially outwards in which an O-ring (16) is disposed.

7. A stem cap according to any one of claims 1 to 3, wherein the body is provided on its outer peripheral edge with a thread screw thread (18) configured to cooperate with a complementary screw thread provided in the orifice.

8. A stem cap according to any one of claims 1 to 3, wherein the finger is equipped with a fir tree pin (33).

9. An electrical / electronic box (66) comprising at least a first bus bar (4) with a first hole (41), a second bus bar (5) with a second hole (52), the first and second holes being substantially coaxial, a casing with at least one orifice (60) located opposite the first and second holes, and a stem cap (10) according to any one of claims 1 to 8, the finger (3) being inserted into the first hole and into the second hole, the shoulder (7) directly or indirectly pressing the first bus bar (4) against the second bus bar (5), and the body (1) hermetically sealing the orifice (60).

10. Electrical / electronic box according to claim 9, in which the orifice (60) has an orifice diameter (D6) at most equal to 3 times the diameter (D3) of the finger.

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