Eddy current apparatus

Abstract

The invention relates to an eddy current device comprising a stator assembly and a rotor assembly adapted to pivot relative to the stator assembly about an axis of rotation, the stator assembly having an annular support (14); the annular support comprising: - a pole core (16) having an internal cavity (18) and a hole (19) opening into the internal cavity, - a pole flare comprising a through hole (28), - a nut (34) housed in the internal cavity (18), and a fixing screw (32) adapted to fix at least one pole flare to the pole core (16); the fixing screw (32) passing through the through hole (28), the hole (19) of the pole core and being screwed into the nut (34). Figure to be published with the abbreviation: Figure 3

Description

Title of the invention: Eddy current apparatus

[0001] The invention relates to an eddy current device and, in particular, to an electromagnetic retarder. Such an electromagnetic retarder makes it possible to supplement the braking systems of vehicles of any category, and in particular land motor vehicles such as trains, heavy goods vehicles or even utility vehicles, for which they are particularly advantageous. State of the prior art

[0002] Eddy current devices comprise a stator assembly and a rotor assembly capable of pivoting relative to the stator assembly about an axis of rotation. To reduce production costs, it is desirable to manufacture a portion of the stator assembly from laminated sheet metal or sintered material. However, laminated sheet metal and sintered materials have poor resistance to the high temperatures induced by radiation from the rotor. Indeed, under the effect of heat, the sheets of the sheet metal detach from each other. Furthermore, it is not possible to drill a hole in a direction perpendicular to the laminated sheets. Presentation of the invention

[0003] It is desirable to allow the manufacture of an annular support made of laminated sheet metal or sintered material which is resistant to radiation induced by the rotor and which lasts over time. Summary of the invention

[0004] The present invention relates to an eddy current apparatus comprising a stator assembly and a rotor assembly capable of pivoting relative to the stator assembly around an axis of rotation, the stator assembly comprising an annular support; the annular support comprising: - at least one polar core comprising an interior cavity and a hole opening into the interior cavity, - at least one polar expansion comprising a through hole, - at least one nut housed in the interior cavity, and at least one fixing screw suitable for fixing the at least one polar expansion to said at least one polar core; said at least one fixing screw passing through the through hole, the hole of the polar core and being screwed into said at least one nut. Advantageously, the creation of an internal cavity containing a nut makes it possible to fix the pole shoes reliably and durably on an annular support made of laminated sheet metal or sintered material. The use of a tapped hole generates design problems and aging problems, including an ef frying of the annular support and a separation of the polar expansions with aging.

[0005] The features set out in the following paragraphs may optionally be implemented. They may be implemented independently of one another or in combination with one another: - the inner cavity comprises an inner wall, the nut abutting a portion of said inner wall, and wherein the ratio between a surface area of ​​the hole in the polar core and the surface area of ​​the nut abutting the inner wall is between 1.05 and 1.3. - the through hole comprises an enlargement, and in which the at least one fixing screw comprises a head; said head being housed in said enlargement.

[0006] - the at least one polar expansion comprises an inner main face and an outer main face; the through hole extending in a direction perpendicular to the inner main face of the at least one polar expansion. - the annular support is made of laminated sheet metal. - the annular support is made of sintered material. - at least one polar expansion is made of solid steel.

[0007] - the at least one nut is made of solid steel. Brief description of the figures

[0008] [Fig. 1] is a perspective view of an eddy current apparatus according to the present invention;

[0009] [Fig.2] is a perspective view of a stator assembly according to the invention; and

[0010] [Fig.3] is a perspective and sectional view of the stator assembly illustrated in the [Fig.2], Detailed description of the invention

[0011] The eddy current apparatus 2 according to the invention is described below in its preferred, but non-limiting, application to an eddy current retarder.

[0012] The eddy current device 2 can also be implemented in an electromagnetic retarder and generator assembly.

[0013] The eddy current apparatus 2 comprises a rotor assembly 4 and a stator assembly 6. The rotor assembly is fixed by means of an intermediate piece on a transmission shaft of a vehicle equipped with the retarder. The rotor assembly 4 comprises an armature sleeve 8, a hub 10 and bent arms 12 which connect the armature sleeve to the hub. The hub is capable of pivoting about an axis of rotation XX.

[0014] The stator assembly 6 according to the first embodiment comprises an annular support 14, inductor coils 20 and pole shoes 22.

[0015] The annular support 14 is fixed with suitable means to the chassis of the vehicle or to the gearbox housing of the vehicle. The axis of the annular support 14 is coaxial with the axis of rotation XX.

[0016] The annular support 14 can be made of laminated sheet metal or sintered material.

[0017] The annular support 14 is provided with internal openings 15 and peripheral polar cores 16. The internal openings 15 extend parallel to the axis of rotation XX. They are through openings. They form a magnetic barrier and allow the annular support to cool.

[0018] The polar cores 16 are distributed at regular intervals along a circle centered on a center O of the rotation axis X. The polar cores have respective axes Y perpendicular to the rotation axis XX.

[0019] With reference to [Fig. 3], the polar cores 16 comprise an interior cavity 18, a hole 19 opening into the interior cavity.

[0020] The inductor coils 20 are shown only in [Fig.l]. The inductor coils 20 are arranged around the pole cores 16.

[0021] The polar expansions 22 are fixed on the free ends of the polar cores 16. The polar expansions 22 serve to immobilize the inductor coils 20 relative to the polar cores 16. The polar expansions also ensure good distribution of the magnetic flux in the induced sleeve 8 and therefore efficient generation of eddy currents.

[0022] Preferably, the polar expansions are made of solid steel so as to protect the annular support 14 from the radiation of the induced sleeve 8.

[0023] The polar expansions comprise an outer main face 24, an opposite inner main face 25 and four side faces 26.

[0024] The outer main face 24 is slightly rounded. The inner main face 25 is opposite the outer main face. The inner main face 25 is flat.

[0025] The polar expansions 22 comprise at least one through hole 28 extending perpendicular to the inner main face 24. The through hole 28 comprises an enlargement 30 at one of its ends. The enlargement 30 opens onto a main face.

[0026] The stator assembly 6 further comprises fixing screws 32 and nuts 34 suitable for fixing the polar expansions 22 to the polar cores 16.

[0027] The fixing screws 32 comprise a head 36 and a rod 38 threaded at least at its end.

[0028] The nuts 34 are made of solid steel.

[0029] The nuts 34 are housed in the interior cavities 18 of the polar cores.

[0030] Each nut 34 rests against a portion of an inner wall 40 of the inner cavity. The inner wall 40 is arranged in a plane substantially parallel to the inner main face 24 of the polar expansions.

[0031] Advantageously, the production of an internal cavity containing a nut makes it possible to fix the polar expansions in a durable manner on a support in which the use of a tapped hole generates problems of crumbling and detachment with age.

Claims

Claims

1. Eddy current apparatus (2) comprising a stator assembly (6) and a rotor assembly (4) capable of pivoting relative to the stator assembly about an axis of rotation (XX), the stator assembly (6) comprising an annular support (14); the annular support (14) comprising: - at least one polar core (16) comprising an interior cavity (18) and a hole (19) opening into the interior cavity, - at least one polar expansion (22) comprising a through hole (28), - at least one nut (34) housed in the interior cavity (18), and at least one fixing screw (32) capable of fixing the at least one polar expansion (22) to said at least one polar core (16); said at least one fixing screw (32) passing through the through hole (28), the hole (19) of the polar core and being screwed into said at least one nut (34).

2. An eddy current apparatus (2) according to claim 1, wherein the inner cavity (18) comprises an inner wall (40), the nut (34) abutting a portion of said inner wall, and wherein the ratio of an area of ​​the hole (19) of the pole core to the area of ​​the nut (34) abutting the inner wall is between 1.05 and 1.

3.

3. An eddy current apparatus (2) according to any one of claims 1 and 2, wherein the through hole (28) comprises an enlargement (30), and wherein the at least one fixing screw (32) comprises a head (36); said head (36) being housed in said enlargement (30).

4. An eddy current apparatus (2) according to any one of claims 1 to 3, wherein the at least one pole shoe (22) comprises an inner main face (24) and an outer main face (25); the through hole (28) extending in a direction perpendicular to the inner main face (24) of the at least one pole shoe.

5. Eddy current apparatus (2) according to any one of claims 1 to 4, wherein the annular support (14) is made of laminated sheet metal.

6. An eddy current apparatus (2) according to any one of claims 1 to 4, wherein the annular support (14) is made of

7. sintered material. Eddy current apparatus (2) according to any one of claims 1 to 6, wherein the at least one pole shoe (22) is made of solid steel.

8. An eddy current apparatus (2) according to any one of claims 1 to 7, wherein the at least one nut (34) is made of solid steel.

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