Electrical connection, electrical machine system comprising such an electrical connection, and method for fastening busbars to a support

Abstract

The electrical connection (110) comprises: - a plurality of busbars (202U-W) designed to connect an inverter to an electrical machine, each busbar (202U-W) having two mounting holes (212U-W, 214U-W); - a bracket (216) designed to support the busbars (202U-W), the bracket (216) comprising: • grooves (218U-W) designed to receive the busbars (202U-W) respectively, and · for each groove (218U-W), two fixing pins (220U-W, 222U-W) projecting from a base (306) of the groove (218U-W) and designed to be received respectively in the fixing holes (212U-W, 214U-W) of the busbar (202U-W) received in the groove (218U-W) and to be riveted to fix the busbars (202U-W) to the bracket (216); where each mounting hole (212U-W, 214U-W) is larger than the mounting pin (220U-W, 222U-W) it receives.

Description

Technical FieldThe present invention relates to an electrical connection, an electrical machine system having such an electrical connection and a method for fastening busbars to a holder.The invention can be used in particular in a mobility device. A mobility device is, for example, a motorized agricultural vehicle, a train, an aircraft or else a drone. A motorized agricultural vehicle is, for example, a motor vehicle, a motorcycle, a motorized bicycle or a motorized wheelchair.Prior ArtThe use of busbars for connecting an inverter to phases of an electric machine is known. The connection points of the inverter and / or the connection points of the electric machine may be slightly offset due to tolerances. The busbars, which are rigid electrical conductors, are therefore bent for compensation.In order to insulate the busbars from the environment, the busbars are often injection-molded together. However, due to the bending of the busbars, the overmolding can tear.The object of the invention is to solve at least partially the aforementioned problems.Disclosure of the InventionThe invention relates to an electrical connection comprising:a plurality of bus bars configured to connect an inverter to an electric machine, each bus bar having two mounting holes;a bracket configured to support the bus bars, the bracket comprising:• grooves configured to receive the bus bars, respectively, and• Two fixing pins protruding from a bottom of the groove, each of which is designed to be received in the fixing holes of the busbar received in the groove and to be riveted to the support for fixing the busbars;wherein each mounting hole is larger than the received mounting pin.The invention may also include one or more of the following optional features in any technically possible combination.Optionally, the mounting hole has a circumference that extends at least 0.5 mm away from the mounting pin over the entire circumference.Optionally, the circumference of each mounting hole extends over the entire circumference at most 1.5 mm from the mounting pin and preferably at most 1 mm from the mounting pin.Likewise optionally, the holder comprises two flexible lugs from which the fastening pins each protrude.Also optionally, each tab extends parallel to the bottom of the groove.Also optionally, each tab is cut into the bottom of the groove.Also optionally, the mounting pin protrudes perpendicular to the tab.Likewise optionally, the brackets are made of plastic.Likewise optionally, the holder is made of plastic.Likewise optionally, at least one of the fastening holes, for example both, is circular for each busbar.Also optionally, at least one of the mounting holes is elongated for each busbar, wherein a first dimension is at least 20% longer than a second dimension perpendicular to the first dimension.Likewise optionally, the holder comprises at least one positioning pin for positioning the holder with respect to a housing of the electric machine.The invention also relates to an electric machine system comprising:an electric machine having a plurality of phases;an inverter; andan electrical connection according to the invention.The invention also relates to a method for fixing busbars, which are designed for connecting an inverter to an electric machine, to a holder, comprising: inserting the busbars into corresponding grooves of the holder and, per groove, inserting two fixing pins, which each protrude from a base of the groove, into two fixing holes of the busbar, wherein each fixing hole is larger than the received fixing pin, such that the fixing hole has a circumference which runs at least 0.5 mm away from the fixing pin over the entire circumference.Optionally, the method further comprises riveting the mounting pins to secure the bus bars to the bracket.Likewise optionally, the method comprises, for each busbar, connecting a first connecting section of the busbar to the inverter and a second connecting section of the busbar to the electric machine, for example by screwing or welding.Brief Description of the DrawingsThe invention will be better understood from the following description, given purely by way of example and referring to the accompanying drawings, in which:FIG. 1 is a schematic view of an electric machine system in which the invention may be practiced,FIG. 2 is a three-dimensional view of an electrical connection according to the invention used in the electrical machine system of FIG. 1 ,FIG. 3 is a three-dimensional view of a portion of the electrical connection,FIG. 4 is a plan view of mounting holes and pins,FIG. 5 is a three-dimensional view similar to FIG. 2 after riveting of the fastening pins; andFIG. 6 is a flow diagram of a method for fastening busbars to a holder.DETAILED DESCRIPTIONReferring now to FIG. 1, an electric machine system 100 in which the invention may be practiced will be described. The electric machine system 100 is configured for use in a mobility device, for example.The electric machine system 100 initially comprises an electric machine 102 having a plurality of phases 104 U, 104V, 104W.The electric machine system 100 further comprises a DC voltage source 106, such as a battery.The electric machine system 100 further comprises an inverter 108 configured to provide the phase voltages U, V, W from the DC voltage source 106.The electric machine system 100 further comprises an electrical connection 110.Referring now to FIG. 2, the electrical connection 110 will be described in more detail.The electrical connection 110 first comprises a plurality of busbars 202 U, 202V, 202W, which are designed to connect the inverter 108 to the phases 104 U-W of the electrical machine 102 in order to conduct the phase voltages U, V, W from the inverter 108 to the corresponding phases 104 U-W of the electrical machine 102. Each bus bar 202 U-W is a rigid, for example bent, ribbon made of an electrically conductive material such as copper.For connection, each bus bar 202 U-W comprises a first connection portion 204 U, 204V, 204W, configured to be connected to the inverter 108, and a second connection portion 206 U, 206V, 206W, configured to be connected to the corresponding phase 104 U-W of the electric machine 102. The connection to the inverter 108 and / or to the phases 104 U-W is effected, for example, by screwing or welding. In the case of screwing, the connecting portion 204 U-W, 206U-W includes, for example, a screw hole 208 U, 208V, 208W, 210U, 210V, 210W.Each busbar 202 U-W further comprises two fastening holes 212 U, 212V, 212W, 214U, 214V, 214W, which are arranged, for example, on the strip between the two connecting portions 204 U-W, 206U-W.The electrical connection 110 further comprises a bracket 216 configured to support the bus bars 202 in U-W fashion. The bracket 216 includes grooves 218U, 218V, 218W configured to receive the bus bars 202 in U-W respectively. The bracket 216 further includes, for each groove 218 U-W, two mounting pins 220 U, 220V, 220W, 222U, 222V, 222W, protruding from a bottom (not shown in FIG. 2 ) of the groove 218 U-W and configured to be respectively received in the mounting holes 212 U-W, 214U-W of the bus bar 202 U-W received in the groove 218 U-W.For example, the holder 216 further comprises at least one positioning pin 224, 226 for positioning the holder 216 with respect to a housing (not shown) of the electric machine 102.The bracket 216 is made of an electrically non-conductive material such as plastic.For example, as can be seen with reference to FIG. 3, the bracket 216 includes, for each groove 218 U-W, two flexible tabs 302, 304 from which the pins each protrude, for example at right angles to the tab 302, 304.Each tab 302, 304 preferably extends parallel to the base, associated reference numeral 306 in FIG. 3, of the groove 218 U-W. For example, each tab 302, 304 is cut into the bottom 306 of the groove 218 in U-W fashion.The tabs 304, 306 are preferably made of plastic to be flexible.Referring to FIG. 4, each mounting hole 212 U-W, 214U-W is larger than the received mounting pin 220 U-W, 222U-W, such that the mounting hole 212 U-W, 214U-W has a perimeter that extends over the entire perimeter at least 0.5 mm and at most 1 mm from the received mounting pin 220 U-W, 222U-W.For each busbar 202 U-W at least one of the mounting holes is, for example, circular (mounting hole 214 U-W in the figures) and / or at least one of the mounting holes is elongate (mounting hole 212 U-W in the figures). The elongated mounting hole has a first dimension d1 that is at least 20% longer than a second dimension d2 perpendicular to the first dimension d1.The circular fastening hole has a circumference which runs at a distance d between 0.6 mm and 0.7 mm.Referring to FIG. 5, the attachment pins 220 U-W are configured to be riveted to attach the bus bars 202 U-W to the bracket 216.Referring to FIG. 6, a method 600 for securing the bus bars 202 U-W to the bracket 216 first includes a step 602 of inserting the bus bars 202 U-W into the grooves 218 U-W of the bracket 216, respectively. During this step, for each groove 218 U-W the two fixing pins are inserted into the two fixing holes 212 U-W respectively.During a step 604, the fastening pins 220 are U-W, 222U-W riveted to fasten the busbars 202 U-W to the holder 216.During a step 606, for each busbar 202 U-W the first connection portion 204 is connected in U-W to the inverter 108 and the second connection portion 206 is connected in U-W to the electric machine 102, for example by screwing or welding.As a result, the invention allows some movement of each bus bar on the groove base 306 with respect to the bracket 116 (in directions X, Y in FIG. 3 ). In addition, the use of the flexible tabs 304, 306 allows some movement perpendicular to the groove base 306 (in the direction Z in FIG. 3 ).It should also be noted that the invention is not limited to the above-described embodiments. It will be readily apparent to those skilled in the art that various modifications may be made to the above-described embodiments in view of the teachings just disclosed.The terms used in the above detailed description of the invention are not to be construed as limiting the invention to the embodiments set forth in the present specification, but must be interpreted to include all equivalents predicted to be apparent to those skilled in the art by applying its general knowledge to the implementation of the teachings just disclosed.

Claims

An electrical connection (110) comprising: - a plurality of busbars (202 U-W), configured to connect an inverter (108) to an electrical machine (102), each busbar (202 U-W) having two mounting holes (212 U-W, 214U-W) ; - a bracket (216) configured to support the busbars (202 U-W) the bracket (216) comprising: • grooves (218 U-W), configured to receive the busbars (202 U-W) respectively, and • for each groove (218 U-W), two mounting pins (220 U-W, protruding from a base (306) of the groove (218 U-W), 222_ner 11_) configured to be respectively received in the fastening holes (212 U-W, 214U-W) of the bus bar (202 U-W) received in the groove (218 U-W) and riveted to fasten the bus bars (202 U-W) to the bracket (216); wherein each fastening hole (212 U-W, 214U-W) is larger than the received fastening pin (220 U-W, 222U-W).The electrical connection (110) of claim 1, wherein the mounting hole (212 U-W, 214U-W) has a perimeter that extends at least 0.5 mm away from the mounting pin (220 U-W, 222U-W) over the entire perimeter.The electrical connection (110) according to claim 1 or 2, wherein the perimeter of each fixing hole (212 U-W, 214U-W) extends over the entire perimeter at most 1.5 mm from the fixing pin (220 U-W, 222U-W) and preferably at most 1 mm from the fixing pin (220 U-W, 222U-W).The electrical connection (110) of any of claims 1 to 3, wherein the bracket (216) comprises two flexible tabs (304, 306) from which the mounting pins (220 U-W, 222U-W) respectively protrude.The electrical connection (110) of claim 4, wherein each tab (304, 306) extends parallel to the bottom (306) of the groove (218 U-W).The electrical connection (110) of claim 4 or 5, wherein each tab (304, 306) is cut into the bottom (306) of the groove (218 U-W).The electrical connection (110) of any of claims 4 to 6, wherein the mounting pin (220 projects U-W, 222U-W) perpendicular to the tab (304, 306).The electrical connection (110) of any of claims 4 to 7, wherein the tabs (304, 306) are made of plastic.The electrical connection (110) of any of claims 1 to 8, wherein the bracket (216) is made of plastic.The electrical connection (110) according to any one of claims 1 to 9, wherein for each busbar (202 U-W) at least one of the mounting holes (212 U-W, 214U-W), for example both are circular or elongated, wherein a first dimension (D1) is at least 20% longer than a second dimension (D2) perpendicular to the first dimension (D1).The electrical connection (110) according to any one of claims 1 to 10, wherein the holder (216) comprises at least one positioning pin (224, 226) for positioning the holder (216) with respect to a housing of the electric machine (102).An electric machine system (100) comprising: - an electric machine (102) having a plurality of phases (104 U-W); - an inverter (108); and - an electrical connection (110) according to any one of claims 1 to 11.

Images