Elastic member for electric power

Abstract

The present subject matter relates to an elastic part (102) for an electric power converter. An electric power converter includes a substrate having conductive traces, a module (104) fixed onto the substrate (102) and disposed parallel to the substrate (102), a heat dissipation member (106) in thermal contact with the module (104), and an elastic part (110). The elastic part (110) includes a body (112) that include two branches (114b), each supporting a bearing element (108a). The bearing element (108a) is configured to press the module (104) onto the heat dissipation member in a direction orthogonal to the substrate and in a direction away from the module (104) relative to the substrate. The two branches (114a; 114b) each at least partially include a sloped portion (204b) inclined in a direction towards the module (104).

Description

Title of the Invention: ELASTIC MEMBER FOR ELECTRIC POWERCONVERTERField of Invention

[0001] The present subject matter relates in general to an electrical power converter, and more specifically, relates to an improved fixation of a module in an electric power converter by means of an elastic member.Background

[0002] An electric power converter is a power electronic device or circuitry that converts direct current (DC) to alternating current (AC), and / or vice versa. Such an electric power converter is notably configured to be placed on board a vehicle, for example, with electric or hybrid propulsion. An electric power converter includes electronic components, such as, power semiconductors, capacitors, etc., that generate heat during operation. A heat sink is used to dissipate heat generated by such electronic components. Typically, the electronic components are disposed orthogonal to an electronic board and is pressed against the heat sink. An elastic member is typically used to press the electronic component onto the heat sink for an efficient heat dissipation. Such elastic members are often susceptible to increased compression stresses that may exceed the yield limit of the elastic member. A prolonged exposure to such an environment may lead to plastification of the elastic member, and eventual failure. This issue is particularly prevalent in vehicle applications, where the electric power converters are subjected to prolonged exposure to vibrations and other harsh environmental conditions. The existing elastic member designs do not adequately address this problem, necessitating the development of an improved solution.

[0003] Therefore, the technical solution sought by the present subject matter is how to an improved elastic member design that can withstand the increased compression stresses and vibrations encountered in vehicle applications without compromising its flexibility and heat dissipation capabilities. The improved designshould ensure the reliable and efficient operation of the electric power converter, contributing to the overall performance and safety of electric and hybrid vehicles.Summary of the invention

[0004] The present subject matter seeks to solve the above-mentioned technical problem in conventional housing for electronic devices particularly suitable for automotive applications.

[0005] The present subject matter relates to an electric power converter comprising: a substrate comprising conductive traces; a module comprising at least one electronic component fixed onto the substrate and disposed parallel to the substrate; a heat dissipation member in thermal contact with the module and configured to dissipated heat emitted by said module; an elastic part comprising a body comprising: two branches each supporting a bearing element, wherein the bearing element is configured to press the module onto the heat dissipation member in a direction orthogonal to the substrate and in a direction away from module relative to the substrate, and wherein the two branches each at least partially comprise a sloped portion inclined in a direction towards the module. Accordingly, by virtue of the sloped portion, there is a reduced stress level on the elastic part. Further, there is less strain levels on the bearing element, thereby ensuring the structural integrity of the elastic part is maintained. Moreover, even on exposure to vibrations, the elastic part ensures that the module is held in place without any unintended movements laterally. Accordingly, the module does not deter from the thermal contact that said module maintains with the heat dissipation member.

[0006] According to an aspect of the present subject matter, the two branches each comprise a bend from which the sloped portion extends, the bend being configured to incline said sloped portion at an angle 9 directed towards the module. This angle 9 of the sloped potion facilitates a reaction force that holds the module in place.

[0007] According to an example, the angle 9 is 7 degrees. This provides an optimal contact force achieved to hold the module in place. Moreover, the clamp’s thickness may be reduced for improved flexibility.

[0008] According to an aspect of the present subject matter, the two branches comprise a first branch supporting a first bearing element, and a second branch supporting a second bearing element, wherein the first bearing element and the second bearing element are configured to press the module onto the heat dissipating member. The first bearing element and the second baring element are each supported by the elastic part so that the module is held in place.

[0009] According to an example of the present subject matter, the first branch and the second branch are arranged parallel to one another and separated by a distance. This arrangement ensures that an even distribution of forces is applied to the bearing element which hold the module in place.

[0010] According to an example of the present subject matter, the first branch and the second branch each comprise a perforation into which the first bearing element and the second bearing element respectively are fitted. Thus, the positioning and fixing of the first bearing element and the second bearing element is facilitated.

[0011] According to an aspect of the present subject matter, the elastic part is disposed on a face of the substrate opposite the face on which the module is disposed. This arrangement allows for improved space management within the electric power converter. Further, the electric power converter may be of smaller size.

[0012] According to an example of the present subject matter, the elastic part is fixed to the heat dissipation member by means of a fastener. Thus, the elastic part is fixed from unintentional movements upon exposure to vibrations, whilst ensuring the bearing element is supported and the module is held in place.

[0013] According to an example of the present subject matter, the body comprises a hole through which the fastener is passed. Thus, the elastic part is held in place within the electric power converter.

[0014] According to an example of the present subject matter, the elastic part comprises a positioning tab received in a receiving hole formed in the substrate, said positioning tab configured to position said elastic part. Thus, the positioning of the elastic part is facilitated on the substrate.

[0015] According to an aspect of the present subject matter, the first bearing element and the second bearing element each pass through the substrate and is pressed directly onto the module. Thus, assembly is facilitated as the elastic part and the first bearing element and the second bearing element are installed without the risk of damaging the module disposed on the other face of the substrate. Further, the electric power converter is made to be compact.

[0016] According to an example of the present subject matter, the body comprises a boss. The boss provides increased stiffness to the body, thereby making the elastic part rigid.

[0017] According to an example of the present subject matter, the electric power converter is configured to be placed on board a vehicle, and operates as a DC-DC converter, an electric charger, or an inverter. The electric power converter forming an inverter is installed, for instance, with a rotary machine that includes a rotor and a stator. Advantageously, the rotary machine can form an alternator, an alternatorstarter, reversible machine, or an electric motor.Brief description of drawings

[0018] The features, aspects, and advantages of the present invention will be better understood with regard to the following description and accompanying figures. The description refers to the annexed drawings, wherein:

[0019] FIG. 1 A is an exploded view of an electric power converter, configured in accordance with the present subject matter;

[0020] FIG. IB is an assembled view of the electric power converter, configured in accordance with the present subject matter;

[0021] FIG. 2A is an isometric view of an elastic part for use in the electric power converter, configured in accordance with the present subject matter;

[0022] FIG. 2B is a side view of the elastic part shown in FIG. 2A, configured in accordance with the present subject matter;

[0023] FIG. 2C is a side view of the elastic part assembled in the electric power converter, configured in accordance with the present subject matter; and

[0024] FIG. 3 illustrates an isometric view of an elastic part for use in an electric power converter, configured in accordance with an example of the present subject matter.

[0025] The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and / or examples consistent with the description; however, the description is not limited to the examples and / or examples provided in the drawings.Detailed Description

[0026] In the description that follows, reference is made to accompanying drawings, which form part thereof, and in which is shown by way of illustration specific implementations in which the invention maybe practiced. These implementations are described in sufficient detail to enable that skilling in the art to practice the invention, and it is to be understood that the implementations may be combined, or that other implementations may be utilized, and that structural and logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0027] The various orientations depicted in the accompanying figures are provided as examples to facilitate a clearer understanding of the invention. The directions indicated by arrows Z, X, and Y are mutually perpendicular to one another.

[0028] FIG. 1A illustrates an exploded view of an electric power converter 100, configured in accordance with the present subject matter. FIG. IB is an assembled view of the electric power converter 100. The description that follows pertain to the aforementioned figures.

[0029] According to the present subject matter, an electric power converter 100 includes a substrate 102 having conductive traces, at least one electronic component 104a fixed to the substrate 102, a heat dissipation member 106 in thermal contact with the module 104, and an elastic part 110. The module 104 includes at least one electronic component 105a, 105b, 105c, 105d disposed parallel to the substrate 102. The heat dissipation member 106 is configured to dissipate heat emitted by said module 104. The elastic part 110 includes a body 112 having two branches 114a, 114b. The two branches 114a, 114b each support a bearing element 108a, 108b. The bearing element 108a, 108b is configured to press the module 104 onto the heat dissipation member 106 in a direction orthogonal to the substrate 102 and away from said substrate 102. Further, the two braches 114a, 114b at least partially includes a sloped portion. The sloped portion of the two branches 114a, 114b are inclined in a direction towards the module 104.

[0030] The module 104 is, for instance, soldered to the substrate 102. The at least one electronic component 105a, 105b, 105c, 105d each may include a plurality of pins (shown in FIG. 2C with reference 208) which are only disposed on one side of said at least one electronic component 105a, 105b, 105c, 105d and are bent and soldered to the substrate 102. The at least one electronic component 105a, 105b, 105c, 105d may include, for instance, between two and five pins. The at least one electronic component 105a, 105b, 105c, 105d is, for instance, a transistor or a diode. In the example shown in FIGs. 1 A and IB, the electric power converter 100 includes four electronic components 105a, 105b, 105c, 105d all identical to oneanother. The substrate 102 is a printed circuit board (PCB) for instance, and may include other electrical or electronic components which are not shown in the figures. According to an aspect of the present subject matter, the module 104, particularly the electronic components 105a, 105b, 105c, 105d form a voltage rectifier bridge for converting alternating voltage generated by phases of a stator into a direct voltage and / or, conversely, for converting a direct voltage into an alternating voltage for powering the phases of the stator.

[0031] The heat dissipation member 106 is configured to dissipate heat emitted by the module 104. For example, the heat dissipation member 106 is made of metal, preferably aluminum based.

[0032] According to an aspect of the present subject matter, the elastic part 110 is disposed on a face of the substrate 102 opposite the face on which the module 104 is disposed. According to another aspect, the elastic part 110 is fastened to the heat dissipating member 106 by a fastener 109, such as a screw. Thus, in the aforementioned aspect, the elastic part 110 is fastened to the heat dissipation member 106 by a fastener 109 so as to hold together the elastic part 110, the substrate 102, and the heat dissipation member 106. The fastener 109 passes through a hole in the elastic part 110.

[0033] According to an aspect of the present subject matter, the substrate 102 includes a means for positioning the elastic part 110. For example, the substrate 102 includes a receiving hole (not shown) for receiving a positioning tab 116a, 116b formed on the elastic part 110, the positioning tab 116a, 116b being formed for positioning the elastic part 110. In the example shown in figures, the elastic part 110 includes two positioning tabs 116a, 116b with the substrate 102 thus provided with two receiving holes receiving the two positioning tabs 116a, 116b. The elastic part 110 supports the bearing element 108a, 108b with the bearing element 108a, 108b pressing onto the module 104 in a direction orthogonal to the substrate 102 and in a direction away from the module 104 relative to the substrate 102, as shown in FIG. 1 A by arrow Z. Arrow Z represents the vertical direction that aligns withthe assembly orientation of the various components, i.e., the elastic part 110, the module 104, the substrate 102, and the heat dissipation member 106, of the electric power converter 100.

[0034] According to an example of the present subject matter, the elastic part 110 is made of metal, such as, stainless steel. The body 112 includes two branches 114a, 114b that form two free ends. When viewed in the top view, the body 112 is U- shaped. Each branch 114a, 114b of the body 112 forms a branch of the U shape. A first branch 114a of the body 112 supports a first bearing element 108a, and a second branch 114b of the body 112 supports a second bearing element 108b. The first bearing element 108a and the second bearing element 108b are identical and are disposed in a similar manner. The elastic part 110 supports the first bearing element 108a and the second bearing element 108b, with the aforementioned first and second bearing elements 108a, 108b pressing onto the module 104 in a direction orthogonal to the substrate 102 and in a direction away from the module 104 relative to the substrate 102, shown by arrow Z. The first bearing element 108a is configured to press the electronic component 105a onto the heat dissipation member 106. The second bearing element 108b is configured to press the electronic component 105b onto the heat dissipation member 106. To this end, the first bearing element 108a and the second bearing element 108b each pass through the substrate 102, for example, via a hole in the substrate 102, and presses directly onto the electronic components 105a, 105b respectively.

[0035] In the example shown in FIGs. 1 A and IB, an additional elastic part 118 is provided, configured in the same manner as the elastic part 110 to support bearing elements 108c and 108d that are configured to press the electronic components 105c and 105d respectively, onto the heat dissipation member 106. Similar more elastic parts similar to elastic part 110 may be provided depending on the number of electronic components provided. In the example shown in figures, the elastic part 110 and the additional elastic part 118 is arranged and aligned in a direction indicated by arrow Y. Accordingly, the electronic components 105a, 105b, 105c, and 105d are arranged and aligned in the direction indicated by arrow Y. Similarly,to push the aforementioned electronic components 105a, 105b, 105c, 105d, the bearing elements 108a, 108b, 108c, 108d are arranged and aligned in the direction indicated by arrow Y.

[0036] According to an aspect of the present subject matter, the first bearing element 108a and the second bearing element 108b are snap fitted onto the elastic part 110. The two branches 114a, 114b are provided with a perforation each through which the bearing elements 108a, 108b is fitted. In an example, the first and second bearing elements 108a, 108b are made of thermoplastic material. Alternatively, in another example, the first and second bearing elements 108a, 108b are overmolded onto the elastic part 110. In yet another example, the first and second bearing elements 108a, 108b and the elastic part 110 form a single piece, preferably made of plastic and / or metal.

[0037] FIG. 2A illustrates an isometric view of the elastic part 110 configured in accordance with the present subject matter. FIG. 2B illustrate a side view of the elastic part 110 shown in FIG. 2A. FIG. 2C illustrates an isometric view of the elastic part 110, configured in accordance with an example of the present subject matter. As described previously, the elastic part 110 includes the body 112, from which two branches are formed: the first branch 114a and the second branch 114b each being provided at least partially with a sloped portion 204a, 204b. The first branch 114a and the second branch 114b are arranged parallel to one another and separated by some distance greater than zero. The first branch 114a and the second branch 114b extend in the direction indicated by arrow X. The elastic part 110 includes two positioning tabs 116a and 116b while the substrate is provided with two receiving holes to receive said positioning tabs 116a and 116b. The elastic part includes a hole 204 through which the fastener 109 is passed as shown in FIGs. 1 A and IB. Further, the two branches 114a, 114b are provided with a perforation 206a, 206b each through which the bearing element 108a, 108b is fitted. Particularly, the first branch 114a and the second branch 114b are provided with a first perforation 206a and a second perforation 206b respectively. The first bearing element 108a issnap fitted via the first perforation 206a; and the second bearing element 108b is snap fitted via the second perforation 206b.

[0038] According to an aspect of the present subject matter, the body 112 may be substantially flat and configured to lie in one plane parallel to X-Y plane defined by arrows X and Y. Alternatively, the body 112 may be provided with an uneven surface (shown in FIG. 3). According to the present subject matter, the two branches 114a, 114b each branch off from the body 112 along the same plane, i.e., X-Y plane. The sloped portion 204a, 204b however inclines in a direction towards the module 104. The two branches 114a, 114b each have the sloped portion 204a, 204b beginning from a bend 200a, 200b that facilitates the sloped portion 204a, 204b to incline. Particularly, the first branch 114a includes a first sloped portion 204a inclined from a first bend 200a; and the second branch 114b includes a second sloped portion 204b inclined from a second bend 200b. Both first bend 200a and second bend 200b are preferably inclined in an angle 0 degrees with respect to a direction shown by arrow X (shown in FIG. 2B) and towards direction shown by arrow Z*, the arrow X being perpendicular to the arrow Z, and the arrow Z* indicating a direction towards the module 104.

[0039] According to an aspect of the present subject matter, the bends 200a, 200b are a start point for an inclination of the two branches 114a, 114b. Specifically, the first branch 114a branches off from the body 112 at a first bend 200a; and the second branch 114b branches off from the body 112 at a second bend 200b. In an example, both the first bend 200a and the second 200b are configured to incline the first sloped portion 204a and second sloped portion 204b respectively towards the direction shown by arrow Z*. Further, in said example, the angle of inclination for both the first sloped portion 204a and the second sloped portion 204b is the same. Alternatively, the first sloped portion 204a and the second sloped portion 204b are different as per requirement. Preferably, in the example where the angle is same for the first sloped portion 204a and the second first sloped portion 204b, the angle 9 degrees equals 7 degree.

[0040] FIG. 3 illustrates an elastic part 300 configured in accordance with an example of the present subject matter. The elastic part 300 resembles the elastic part 110 in every way except that the body 112 of elastic part 110 is substantially flat while the elastic part 300 has a body 302 with an uneven surface. Particularly, this uneven surface is a boss 304. This boss 304 can be obtained, for instance, by stamping the elastic part during manufacturing process.

[0041] According to the present subject matter, the electric power converter 100 (shown in FIGs. 1A and IB, previously described, is configured to be placed on board a vehicle, and forms a DC-DC converter configured to convert a voltage between a high-voltage power supply battery and a low-voltage power supply battery. The low voltage ranges between 5 and 50 volts. The high voltage ranges between 220 and 1500 volts.

[0042] Alternatively, the electric power converter 100 forms an electric charger configured to convert a voltage between an electric network outside the vehicle and a power supply battery of the vehicle.

[0043] In yet another alternate configuration, the electric power converter 100 forms an inverter configured so as to power a rotary machine driving the vehicle from a power supply battery, the inverter being configured to convert direct current supplied by the power supply battery into alternating current for powering the rotary machine, and vice versa. In an example, the electric power converter 100 forming an inverter is mounted in a rotary machine that includes a rotor and a stator. This rotary machine can form an alternator, an alternator- starter, a reversible machine, or an electric motor.

[0044] Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, will become apparent to persons skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications can be made without departing from the scope of the present subject matter is defined.

Claims

We Claim:

1. An electric power converter (100) comprising: a substrate (102) comprising conductive traces; a module (104) comprising at least one electronic component (105a; 105b; 105c; 105d) fixed onto the substrate (102) and disposed parallel to the substrate (102); a heat dissipation member (106) in thermal contact with the module (104) and configured to dissipated heat emitted by said module (104); an elastic part (110; 118; 300) comprising a body (102; 302) comprising: two branches (114a; 114b) each supporting a bearing element (108a; 108b; 108c; 108d), wherein the bearing element (108a; 108b; 108c; 108d) is configured to press the module (104) onto the heat dissipation member (106) in a direction orthogonal to the substrate (102) and in a direction away from module (104) relative to the substrate (102), and wherein the two branches (114a; 114b) each at least partially comprise a sloped portion (204a; 204b) inclined in a direction towards the module (104).

2. The electric power converter (100), as claimed in claim 1, wherein the two branches (114a; 114b) each comprise a bend (200a; 200b) from which the sloped portion (204a; 204b) extends, the bend (200a; 200b) being configured to incline said sloped portion (204a; 204b) at an angle 9 directed towards the module (104).

3. The electric power converter (100), as claimed in the preceding claim, wherein the angle 9 is 7 degrees.

4. The electric power converter (100), as claimed in claim 1, wherein the two branches (114a; 114b) comprise a first branch (114a) supporting a first bearing element (108a), and a second branch (114b) supporting a second bearing element (108b), wherein the first bearing element (108a) and the second bearing element (108b) are configured to press the module (114) onto the heat dissipating member (106).

5. The electric power converter (100), as claimed in the preceding claim, wherein the first branch (114a) and the second branch (114b) are arranged parallel to one another and separated by a distance.

6. The electric power converter (100), as claimed in the preceding claim, wherein the first branch (114a) and the second branch (114b) each comprise a perforation (206a; 206b) into which the first bearing element (108a) and the second bearing element (108b) respectively are fitted.

7. The electric power converter (100), as claimed in the preceding claim, wherein the elastic part (110; 118; 300) is disposed on a face of the substrate (102) opposite the face on which the module (104) is disposed.

8. The electric power converter (100) as claimed in any one of the preceding claims, wherein the elastic part (110; 118; 300) is fixed to the heat dissipation member (106) by means of a fastener (109).

9. The electric power converter (100), as claimed in the preceding claim, wherein the body (102; 302) comprises a hole (204) through which the fastener (109) is passed.

10. The electric power converter (100) as claimed in any one of the preceding claims, wherein the elastic part (110; 118; 300) comprises apositioning tab (116a; 116b) received in a receiving hole formed in the substrate (102) , said positioning tab (116a; 116b) configured to position said elastic part (110; 118; 300).

11. The electronic power converter (100) as claimed in any one of the preceding claims, wherein the first bearing element (108a) and the second bearing element (108b) each pass through the substrate (102) and is pressed directly onto the module (104).

12. The electronic power converter (100) as claimed in any one of the preceding claims, wherein the body (102; 302) comprises a boss (304).

13. The electric power converter (100) as claimed in any of the preceding claims, is configured to be place on board a vehicle, and operates as a DC-DC converter, an electric charger, or an inverter.

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