ARRANGEMENT OF PARTS AND METHODS FOR MANUFACTURING SUCH AN ARRANGEMENT

Description

TECHNICAL FIELD

[0001] The present invention relates to an assembly of parts and a method of manufacturing such an assembly. TECHNOLOGICAL BACKGROUND

[0002] Documents US 2012 / 216390, EP 1 361 370 and US 5 251 370 known from the prior art describe assemblies of parts. The PCT international application published under number WO 2006 129 031 A1 describes an assembly of parts of the type comprising: a first part provided with a vertical conduit having a lower part and an upper part, a second part resting on an upper face of the first part and provided with a hole receiving the upper part of the conduit.

[0003] In the previous PCT international application, this assembly is part of a voltage converter intended to be connected to an electrical machine, and to be fixed to a third part, in this case an upper plate of this electrical machine. For this, the upper part of the conduit is folded by riveting against the second part, and a stud is inserted into the conduit and screwed to the upper plate of the electrical machine. Thus, the voltage converter is wedged between the electrical machine and the head of the stud which presses on the riveted upper part of the conduit.

[0004] The previous fixing system has the advantage of being very compact since the fixing of the first and second parts is carried out in the same place as the fixing of the third part.

[0005] The invention aims to provide a more reliable assembly of parts. SUMMARY OF THE INVENTION

[0006] For this purpose, an assembly of parts of the aforementioned type is proposed, characterized in that the second part has, in the hole, a shoulder against which the upper part of the conduit is folded down so as to clamp the second part between the folded down upper part of the conduit and the upper face to fix the second part to the first part.

[0007] Thus, the part assembly is more reliable because the upper part remains inside the hole, so that it is possible to fix the assembly by means of a rod introduced into the hole of the second part and into the conduit of the first part and having an upper end provided with a stop resting on an upper face of the second part, and not on the folded upper part of the conduit since it is located in the hole, under the stop.

[0008] The part assembly further includes: a third part having a hole located below and in the continuity of the conduit, a fixing rod extending successively into the hole of the second part, into the conduit of the first part and into the hole of the third part, the fixing rod having an upper end provided with a stop resting on an upper face of the second part.

[0009] Optionally, the conduit is made of metal.

[0010] Also optionally, the first part is a single block with the duct.

[0011] Optionally also, the first part and the second part are part of a voltage converter, the first part being a heat sink intended to dissipate heat from power components of the voltage converter and the second part being a housing intended to receive an electronic card for controlling the power components.

[0012] Also optionally, the third part is part of an electrical machine connected to the voltage converter.

[0013] A method of manufacturing an assembly of parts according to the invention is also proposed, comprising: obtaining the first part, obtaining the second part, positioning the second part so that the hole in the second part is located above and in continuity with the conduit and receives the projection(s), riveting the projection(s) against the shoulder of the hole in the second part to fix the second part to the first part. obtaining a third part having a hole, positioning the assembly of the first and second parts so that the hole in the third part is located below and in continuity with the conduit, fixing the third part to the assembly of the first and second parts by means of a fixing rod extending successively into the hole in the second part, into the conduit of the first part and into the hole in the third part, the fixing rod having an upper end provided with a stop resting on an upper face of the second part. DESCRIPTION OF FIGURES

[0014] There figure 1 is an electrical diagram of an electrical system comprising a voltage converter implementing the invention. The figure 2 is a three-dimensional view of power modules and a heat sink of the voltage converter of the figure 1 . There figure 3 is a three-dimensional view of the elements of the figure 2 , completed with an electronic control card and an electronic card receiving box. The figure 4 is a three-dimensional section showing a heat sink and housing mounting system. The figure 5 is a sectional view of the fixing system of the figure 4 . There figure 6 is a view similar to the figure 5 , further illustrating the attachment of the voltage converter to an electrical machine. The figure 7 is a block diagram illustrating the successive steps of a method according to the invention for assembling parts. DETAILED DESCRIPTION

[0015] In reference to the figure 1 , an electrical system 100 implementing the invention will now be described.

[0016] The electrical system 100 is for example intended to be installed in a motor vehicle.

[0017] The electrical system 100 firstly comprises an electrical power source 102 designed to deliver a direct voltage U, for example between 20 V and 100 V, for example 48 V. The electrical power source 102 comprises for example a battery.

[0018] The electrical system 100 further comprises an electrical machine 130 comprising several phases (not shown) intended to have respective phase voltages.

[0019] The electrical system 100 further comprises a voltage converter 104 connected between the electrical power source 102 and the electrical machine 130 to perform a conversion between the direct voltage U and the phase voltages.

[0020] The voltage converter 104 firstly comprises a positive bus bar 106 and a negative bus bar 108 intended to be connected to the electrical power source 102 to receive the direct voltage U, the positive bus bar 106 receiving a high electrical potential and the negative bus bar 108 receiving a low electrical potential.

[0021] The voltage converter 104 further comprises at least one power module 110 comprising one or more phase bus bars 122 intended to be respectively connected to one or more phases of the electrical machine 130, to provide their respective phase voltages.

[0022] In the example described, the voltage converter 104 comprises three power modules 110 each comprising two phase bus bars 122 connected to two phases of the electrical machine 130.

[0023] More specifically, in the example described, the electrical machine 130 comprises two three-phase systems each comprising three phases, and intended to be electrically phase-shifted by 120° relative to each other. Preferably, the first phase bus bars 122 of the power modules 110 are respectively connected to the three phases of the first three-phase system, while the second phase bus bars 122 of the power modules 110 are respectively connected to the three phases of the second three-phase system.

[0024] Each power module 110 comprises, for each phase bus bar 122, a high side switch 112 connected between the positive bus bar 106 and the phase bus bar 122 and a low side switch 114 connected between the phase bus bar 122 and the negative bus bar 108. Thus, the switches 112, 114 are arranged to form a chopping arm, in which the phase bus bar 122 forms a midpoint.

[0025] Each switch 112, 114 comprises first and second main terminals 116, 118 and a control terminal 120 for selectively opening and closing the switch 112, 114 between its two main terminals 116, 118 as a function of a control signal applied thereto. The switches 112, 114 are preferably transistors, for example metal-oxide-semiconductor field effect transistors (MOSFETs) having a gate forming the control terminal 120, and a drain and a source respectively forming the main terminals 116, 118.

[0026] In the example described, the switches 112, 114 each have the shape of a plate, for example substantially rectangular, having an upper face and a lower face. The first main terminal 116 extends on the lower face, while the second main terminal 118 extends on the upper face. In addition, the lower face forms a heat dissipation face.

[0027] The voltage converter 104 further comprises, for each power module 110, a capacitor 124 having a positive terminal 126 and a negative terminal 128 respectively connected to the positive bus bar 106 and to the negative bus bar 108.

[0028] It will be appreciated that the positive bus bar 106, the negative bus bar 108 and the phase bus bars 122 are rigid members designed to carry electrical currents of at least 1 A. They preferably have a thickness of at least 1 mm.

[0029] Furthermore, in the example described, the electric machine 130 has both an alternator and an electric motor function. More specifically, the motor vehicle further comprises a heat engine (not shown) having an output shaft to which the electric machine 130 is connected by a belt (not shown). The heat engine is intended to drive wheels of the motor vehicle via its output shaft. Thus, when operating as an alternator, the electric machine supplies electrical energy to the electrical power source 102 from the rotation of the output shaft. The voltage converter 104 then functions as a rectifier. When operating as an electric motor, the electric machine drives the output shaft (in addition to or instead of the heat engine). The voltage converter 104 then functions as an inverter.

[0030] The electrical machine 130 is for example located in a gearbox or in a clutch of the motor vehicle or in place of the alternator.

[0031] In the following description, the structure and arrangement of elements of the voltage converter 104 and of the electric machine 130 will be described in more detail, with reference to a vertical direction HB, “H” representing the top and “B” representing the bottom.

[0032] In reference to the figure 2 , the voltage converter 104 comprises a heat sink 202 intended to dissipate the heat from the switches 112, 114. The heat sink 202 is preferably made of metal and formed from a single block. The heat sink 202 comprises at least one vertical conduit 203 for attachment to the electrical machine 130, delimiting a rod passage hole, as will be explained later.

[0033] In reference to the figure 3 , the voltage converter 104 further comprises a control module 302, 304 intended to control the switches 112, 114, comprising an electronic card 302 and a housing 304 for receiving the electronic card 302.

[0034] In reference to the figure 4 , each conduit 203 comprises a lower part 401 and an upper part 402 rising, in the example described, from an upper face 404 of the lower part 401. In the example described, the upper part 402 comprises several projections each having the shape of a low wall extending circumferentially around the hole delimited by the conduit 203.

[0035] The housing 304 comprises a main body 406 and hollow inserts 408 fixed to the main body 406. More specifically, the main body 406 has openings in which the hollow inserts 408 are respectively inserted integrally with the main body 406. The hollow inserts 408 are for example made of metal, for example aluminum, and the main body 406 of the housing 304 is for example made of plastic, for example overmolded around the hollow inserts 408. Each hollow insert 408 of the housing 304 rests, in the example described, on the upper face 404 of an associated conduit 203 and is provided with a through hole 409 located above the associated conduit 203, in its continuity, and receiving the upper part 402 of the conduit.

[0036] Furthermore, the hollow insert 408 has, in the hole 409, a shoulder 410 against which the upper part 402 of the conduit 203 is intended to be folded down by riveting to fix the housing 304 to the heat sink 202, by enclosing the shoulder 410 between the folded down upper part 402 and the upper face 404 of the conduit 203.

[0037] The assembly obtained after riveting the upper part 402 of the conduit 203 is illustrated in the figure 5 .

[0038] In reference to the figure 6 , the voltage converter 104 is intended to be mechanically fixed to the electrical machine 130.

[0039] For this purpose, the electric machine 130 has holes 602 respectively located below and in the continuity of each conduit 203 of the heat sink 202. A rod 604 extends successively into the hole 409 of the housing 304, into the hole delimited by the conduit 203 of the heat sink 202 and into the hole 602 of the electric machine 130. The rod 604 is provided with a lower end fixed to the electric machine 130, for example screwed into the hole 602. The rod 604 further has an upper end having a stop 606 resting on an upper face 608 of the insert 408, this upper face 608 being located above the shoulder 410. Thus, the housing 304 and the heat sink 202 are wedged between the electric machine 130 and the stop 606.

[0040] The stop 606 presses on the upper face 608 which has a harder and more regular surface than the folded upper part 402 of the conduit 203. Thus, the stop 606 is more stable than if it pressed on the folded upper part 402 of the conduit 203.

[0041] The rod 604 and the stop 606 are for example formed by a screw, the head of the latter, possibly completed with a washer, forming the stop 606. Alternatively, the stop 606 could be formed by a nut screwed onto the upper end of the rod 604.

[0042] In reference to the figure 7 , a method of assembling 700 parts will now be described.

[0043] In a step 702, the heat sink 202 is obtained.

[0044] During a step 704, the housing 304 is obtained.

[0045] During a step 706, the housing 304 is placed so that, on the one hand, the hole 409 of each hollow insert 408 is located above the associated conduit 203, in its continuity, and receives the upper part 402 of the conduit 203 and, on the other hand, each hollow insert 408 rests on the upper face 404 of the associated conduit 203.

[0046] In a step 708, the upper portion 402 of the conduit 203 is riveted against the shoulder 410 to secure the housing 304 to the heat sink 202, as illustrated in the figure 5 .

[0047] During a step 710, the switches 112, 114 are electrically connected to the electronic card 302. Step 710 may also include other operations, such as for example: resinating the PCB (acronym for "Printed Circuit Board") housing, installing a cover, etc.

[0048] During a step 712, the voltage converter 104 is transported to the mounting location on the electrical machine 130.

[0049] During a step 714, the electric machine 130 is obtained.

[0050] During a step 716, the voltage converter 104 is fixed on the electric machine 130 by means of a rod extending successively in the hole 409 of the housing 304, in the conduit 203 of the heat sink 202 and in the hole 602 of the electric machine 130 and of a stop located on an upper end of the rod and resting on the upper face 608 of the insert 408, as illustrated in the figure 6 .

[0051] The present invention is not limited to the embodiment described above, but is instead defined by the following claims. It will indeed be apparent to those skilled in the art that modifications may be made thereto.

Claims

1. Assembly of parts comprising: - a first part (202) provided with a vertical conduit (203) having a lower part (401) and an upper part (402), - a second part (304) resting on an upper face (404) of the first part (202) and provided with a hole (409) receiving the upper part (402) of the conduit (203), - a third part (130) having a hole (602) located below and in line with the conduit (203), and - a fixing rod (604) extending successively into the hole (409) of the second part (304), into the conduit (203) of the first part (202) and into the hole (602) of the third part (130), the fastening rod (604) having an upper end provided with a stop (606) resting on an upper face (608) of the second part (304), and in that the second part (304) has, in the hole (409), a shoulder (410) against which the upper part (402) of the conduit (203) is folded down so as to clamp the second part (202) between the foldeddown upper part (402) of the conduit (203) and the upper face (404) to fix the second part (304) to the first part (202).

2. Assembly of parts according to claim 1, wherein the conduit (203) is made of metal.

3. Assembly of parts according to claim 1 or 2, wherein the first part (202) is integral with the conduit (203).

4. Assembly of parts according to any of claims 1 to 3, wherein the first part (202) and the second part (304) are part of a voltage converter (104), the first part (202) being a heat sink for dissipating heat from power components (112, 114) of the voltage converter (104) and the second part (304) being a housing for receiving an electronic control board (302) for the power components (112, 114).

5. Assembly of parts according to the previous claim, wherein the third part (130) is part of an electric machine (130) connected to the voltage converter (104).

6. Method of manufacturing an assembly of parts according to any of claims 1 to 5, comprising: - obtaining the first part (202), - obtaining the second part (304), - positioning the second part (304) so that the hole (409) in the second part (304) is located above and in line with the conduit (203) and receives the upper part (402) of the conduit (203), - riveting the upper part (402) of the conduit (203) against the shoulder (410) of the second part (304) to secure the second part (304) to the first part (202), - obtaining a third part (130) having a hole (602), - positioning the assembly of the first and second parts (202, 304) so that the hole (602) of the third part (130) is located below and in line with the conduit (203), - fixing the third part (130) by means of a fixing rod (604) extending successively into the hole (409) of the second part (304), into the conduit (203) of the first part (202) and into the hole (602) of the third part (130), the fixing rod (604) having an upper end provided with a stop (606) resting on an upper face (608) of the second part (304).