Braking system, braking method and vehicle incorporating such a braking system

Abstract

The invention relates to a braking system for a vehicle comprising: - a brake disc (8) having a first flat face (14), - a brake pad (12) fixed to the pad support opposite a first circular portion (20) of the first flat face of the brake disc, - a brake pad displacement device (13) adapted to bring the brake pad against a first circular portion (20) of the first flat face of the brake disc, - an inductor (22, 26) of an electromagnetic retarder adapted to generate eddy currents towards the first flat face (14) of the brake disc, the electromagnetic retarder inductor being arranged opposite a second circular portion (24) of the brake disc. Figure to be published with the abbreviation: Figure 1

Description

Title of the invention: Braking system, braking method and vehicle comprising such a braking system Technical field of the invention

[0001] The braking system according to the invention can be mounted on light vehicles, industrial vehicles, trains and metros. State of the prior art

[0002] Many vehicles are equipped with friction brakes mounted on each of the vehicle's wheels. However, with this type of brake, the friction of the brake linings on the disc causes emissions of polluting particles.

[0003] In addition, the friction of the brake linings on the disc causes a rapid rise in the temperature of the brake linings and the disc. This rise in temperature degrades the performance of the brake. Presentation of the invention

[0004] A first aim of the present invention is to reduce these emissions of polluting particles.

[0005] A second object of the present invention is to use frictionless electromagnetic braking for slowing down and to preserve the important performance of friction braking for safe emergency braking. Summary of the invention

[0006] To this end, the present invention relates to a braking system intended for a vehicle comprising a body, a hub mounted to rotate relative to the body, the hub having an axis of rotation, the braking system comprising: - a brake disc intended to be fixed to the hub, said brake disc having an axis of rotation, a first flat face, a second flat face opposite the first flat face, - a plate holder, - at least one brake pad fixed to the pad support opposite a first circular portion of the first flat face of the brake disc, - a moving device capable of moving the brake pad relative to the brake disc to bring the brake pad against a first circular portion of the first flat face of the brake disc, characterized in that it further comprises at least one inductor of an electromagnetic retarder capable of generating eddy currents towards the first flat face of the brake disc to slow the brake disc, said electromagnetic retarder inductor being arranged opposite a second circular portion of the disc brake.

[0007] 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:

[0008] - the first circular portion is distinct and angularly offset from the second circular portion. - The first circular portion extends over a first angular range, the second circular portion extends over a second angular range, the second angular range is between 100 degrees and 250 degrees. - the first circular portion extends over a first angular range, the second circular portion extends over a second angular range, the first angular range is complementary to the second angular range. -At least a portion of the first flat face of the brake disc is covered by at least a first coating, the first coating being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel. -The material includes one of copper, silver, and gold. -The first coating has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 2 millimeters. -The first coating is covered by a second coating. - The second coating comprises a material from among steel or cast iron. - The second coating has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 1.5 millimeters. - The braking system comprises two inductors and a support caliper suitable for carrying said inductors; said support caliper comprising a first and a second support plate each carrying an inductor, the first support plate being arranged opposite at least a portion of the first flat face of the brake disc, and the second support plate being arranged opposite a portion of the second flat face of the brake disc, the first support plate and the second support plate being fixed to each other. - The first circular portion is delimited by an internal radius, an external radius and a center located on the axis of rotation, the second circular portion is delimited by an internal radius, an external radius, and a center located on the axis of rotation; and in which the internal radius of the first circular portion is greater than or equal to the external radius of the second circular portion. - Only a portion of the first flat face of the brake disc is covered with a first coating, said portion having the shape of a crown having an outer radius substantially equal to the outer radius of the second circular portion, the first coating being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel. - The material includes one of copper, silver, and gold. - The first coating has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 2 millimeters. The invention also relates to a vehicle comprising a body, a fixed hub movable in rotation relative to the body, characterized in that it comprises a braking system as mentioned above, the brake disc being integral in rotation with the hub, said pad support being carried by the body and the first support plate being fixed to the body. The invention also relates to a braking method implemented by a braking system as mentioned above which comprises the following steps: - receiving a braking command; - power supply of at least one inductor of an electromagnetic retarder; - application of said at least one brake pad against the brake disc. Brief description of the figures

[0009] [Fig-1] is a perspective view of a braking system according to a first embodiment of the invention; and

[0010] [Fig.2] is a side view of a flat face of a brake disc of the braking system illustrated in [Fig.l];

[0011] [Fig.3] is a view of a section along a horizontal plane passing through the axis of rotation AA of the hub and the brake disc of the braking system illustrated in [Fig.l];

[0012] [Fig.4] is a view of a section along a horizontal plane passing through the axis of rotation AA of the hub and of a variant of the brake disc of the braking system illustrated in [Fig.l];

[0013] [Fig.5] is a side view of a braking system according to a second embodiment of the invention;

[0014] [Fig.6] is a view of a section along a horizontal plane passing through the axis of rotation AA of the hub and the brake disc of the braking system illustrated in [Fig.5]. Detailed description of the invention

[0015] The present invention relates to a braking system and a vehicle comprising this braking system. The vehicle is for example a motor vehicle, a truck or a heavy goods vehicle, a train carriage or a subway carriage.

[0016] The vehicle comprises a body 2 shown schematically in [Fig.l], hubs 4 fixed to the body and wheels (not shown) fixed to the hubs. Each hub is rotatable relative to the body around an axis of rotation AA.

[0017] With reference to [Fig.l], the braking system 6 according to a first embodiment of the invention comprises a brake disc 8, a pad support 10 and at least one brake pad 12.

[0018] The brake disc 8 is integral with the hub 4 so that its center is located on the axis of rotation AA. The axis of rotation of the brake disc 8 coincides with the axis of rotation AA.

[0019] The brake disc 8 comprises a first flat lateral face 14 and a second flat lateral face 16 opposite the first flat face. In the illustrated embodiment, the brake disc is perforated to allow heat dissipation.

[0020] In the embodiment shown, the pad support 10 consists of a shell provided with a longitudinal opening 18 through which a portion of the brake disc passes. A portion of the brake disc 8 is arranged in the shell of the brake disc.

[0021] The plate support 10 is fixed to the body 2.

[0022] The pad support 10 contains and carries a first brake pad 12, a second brake pad (not shown) and a moving device 13 capable of moving the brake pads against the brake disc following receipt of a braking command.

[0023] The first brake pad 12 is arranged opposite the first flat face 14 of the brake disc. The second brake pad is arranged opposite the second flat face 16 of the brake disc.

[0024] The brake pads each comprise a sole provided with a lining.

[0025] In particular, the first brake pad 12 is located opposite a first circular portion 20 of the first flat face of the brake disc. In the same way, the second brake pad is located opposite a first circular portion of the second flat face of the brake disc. The first circular portion 20 of the first flat face of the brake disc is shown in [Fig. 2]. The first circular portion of the second flat face of the brake disc is not visible in the figures. The first circular portions extend along an edge of the brake disc over a first angular range a having as its center a point on the axis of rotation AA of the brake disc. The braking system 6 further comprises a first inductor 22 of an electromagnetic retarder arranged opposite the first flat face 14 of the brake disc. The first inductor 22 is capable of generating eddy currents towards this first flat face 14 of the brake disc to slow down the brake disc 8. In particular, the first inductor 22 of the electromagnetic retarder is located in facing a second circular portion 24 of the first flat face 14 of the brake disc.

[0026] The second circular portion 24 extends over a second angular range [3 having as its center a point on the axis of rotation AA of the brake disc.

[0027] For example, the second angular range [3 is between 100 degrees and 250 degrees.

[0028] The first circular portion 20 is distinct and angularly offset from the second circular portion 24. In the embodiment illustrated in [Fig.l], there is no overlap between the first circular portion 20 and the second circular portion 24.

[0029] According to a variant not shown, the first angular range a is complementary to the second angular range [3. In other words, the whole of the first angular range a and the second angular range [3 is substantially equal to 360°.

[0030] In the same way, the braking system 6 further comprises a second inductor 26 of an electromagnetic retarder arranged opposite the second flat face 16 of the brake disc and capable of generating eddy currents towards this second flat face. The second inductor 26 of the electromagnetic retarder is located opposite a second circular portion of the second flat face 16 of the brake disc.

[0031] The inductors 22, 26 comprise electromagnetic coils 30 electrically connected to a power source 32. Only one electrical connection has been shown in [Fig.l]. The other electrical connections have not been shown.

[0032] The electromagnetic coils 30 comprise axial projections surrounded by conductive electrical wires connected to the power source 32. When an electric current is generated by the power source 32, the electromagnetic coils emit a magnetic field towards the brake disc.

[0033] Thus, the brake disc, and in particular the first flat face 14 and the second flat face 16 of the brake disc, constitute armatures of an electromagnetic retarder.

[0034] With reference to [Fig. 3], at least a portion of the first flat face 14 of the brake disc is covered by a first coating 34. In the embodiment shown as an example, the portion of the brake disc covered with the first coating is between the peripheral edge of the brake disc and a dotted line. In practice, the first coating 34 covers at least one crown having a dimension in a radial direction at least equal to the dimension of the second circular portion 24 in the radial direction.

[0035] Preferably, at least a portion of the second flat face 16 of the brake disc is covered by the first coating 34.

[0036] Alternatively, the entire first flat face and / or second face is covered with the first coating.

[0037] The first coating 34 is made of a material having high electromagnetic conductivity so as to promote the propagation of electromagnetic fields in the brake disc.

[0038] In particular, the first coating 34 is made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel.

[0039] This material is for example copper, silver or gold.

[0040] Preferably, the first coating 34 has a thickness of between 1 millimeter and 3 millimeters. More preferably, the first coating 34 has a thickness of between 1 millimeter and 2 millimeters.

[0041] In the same way, at least a portion of the second flat face 16 of the brake disc is covered by the first coating 34.

[0042] Advantageously, this first coating 34 increases the effectiveness of braking by electromagnetic retarders because it promotes the propagation of eddy currents in the brake disc.

[0043] According to an alternative embodiment of the brake disc shown in [Fig.4], the first coating 34 is covered by a second coating 36.

[0044] The second coating 36 comprises a material from among a steel or a cast iron.

[0045] The second coating 36 has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 1.5 millimeters.

[0046] Alternatively, the entire first flat face and / or second flat face is covered with the first coating.

[0047] Advantageously, the second coating makes it possible to protect the first coating from wear generated by the friction of the brake pad lining against the flat faces of the brake disc.

[0048] The braking system 6 comprises a support caliper 38 suitable for carrying the first 22 and the second 26 inductors. The support caliper 38 comprises a first 40 and a second 42 support plate each carrying an inductor.

[0049] The first support plate 40 arranged opposite and at a short distance from at least a portion of the first flat face 14 of the brake disc. Electromagnetic coils 30 are fixed to the first support plate.

[0050] The second support plate 42 is arranged opposite and at a short distance from a portion of the second flat face 16 of the brake disc. Electromagnetic coils 30 are fixed to the second support plate. The first support plate and the second support plate are fixed to each other the other by fixing rods 44 extending in a direction parallel to the axis of rotation AA.

[0051] With reference to [Fig. 5], the braking system 46 according to a second embodiment is similar to the braking system 6 according to the first embodiment. The same elements have been referenced by the same references and will not be described in detail a second time.

[0052] The braking system 46 comprises a brake disc 8, a pad support 10 carrying brake pads 12 and a device 13 for moving the brake pads.

[0053] The brake disc 8 comprises a first flat face 48 and a second opposite flat face 49.

[0054] In this embodiment, the first brake pad 12 is located opposite a first circular portion 50 of the first flat face of the brake disc.

[0055] The first circular portion 50 is delimited by an internal radius RII, an external radius RE1 and a center 0 located on the axis of rotation AA.

[0056] The braking system 46 further comprises a first inductor 52 of an electromagnetic retarder arranged opposite the first flat face 48 of the brake disc. The first inductor 52 is capable of generating eddy currents towards this first flat face 48 of the brake disc to slow down the brake disc 8. In particular, the first inductor 52 of the electromagnetic retarder is located opposite a second circular portion 54 of the first flat face of the brake disc.

[0057] The second circular portion 54 is delimited by an internal radius RI2 and an external radius RE2. The second circular portion 54 is concentric with the first circular portion 50. In this embodiment, the internal radius RII of the first circular portion 50 is greater than the external radius RE2 of the second circular portion 54. In other words, the first circular portion 50 is arranged in a crown which encircles the second circular portion 54.

[0058] In this embodiment, only a central portion of the first flat face of the brake disc is covered with the first coating 34.

[0059] This central portion has the shape of a crown having an inner radius RI2 substantially equal to the radius of the hub 4 and an outer radius substantially equal to the outer radius RE2 of the second circular portion. The first coating 34 is made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel. This material comprises one of copper, silver and gold.

[0060] Thus, the brake pads are not applied to the same portion of the brake disc as the eddy currents, even when the wheel is rotating.

[0061] Advantageously, the first coating 34 is not damaged by the friction of the brake pad lining.

[0062] Alternatively, the first coating 34 is covered by a second coating 36. The second face of the brake disc is identical to the first flat face and will not be described a second time.

[0063] This braking system 46 is suitable for vehicles having large diameter brake discs such as heavy goods vehicles or train or metro cars.

[0064] According to the present invention, during a braking command, the electromagnetic retarders are first powered by the power source 32 until the wheel has reached a predefined speed, then the brake pads are actuated. For this purpose, the displacement device 13 shown schematically, applies the lining of the brake pad against the flat face of the brake disc and causes friction braking.

Claims

Claims

1. Braking system (6; 46) intended for a vehicle comprising a body (2), a hub (4) mounted so as to be able to rotate relative to the body, the hub (4) having an axis of rotation (AA), the braking system comprising: - a brake disc (8) intended to be fixed to the hub, said brake disc (8) having an axis of rotation, a first flat face (14; 48), a second flat face (16; 49) opposite the first flat face, - a pad support (10), - at least one brake pad (12) fixed to the pad support opposite a first circular portion (20; 50) of the first flat face of the brake disc, - a displacement device (13) capable of moving the brake pad relative to the brake disc to bring the brake pad against a first circular portion (20) of the first flat face of the brake disc, characterized in that it further comprises at least one inductor (22, 26;52) an electromagnetic retarder capable of generating eddy currents towards the first flat face (14; 48) of the brake disc to slow down the brake disc, said electromagnetic retarder inductor being arranged opposite a second circular portion (24; 54) of the brake disc.;

2. A braking system (6) according to claim 1, wherein the first circular portion (20) is distinct and angularly offset from the second circular portion (24).

3. Braking system (6) according to any one of claims 1 and 2, wherein the first circular portion (21) extends over a first angular range (a), the second circular portion (24) extends over a second angular range (|3), the second angular range (|3) is between 100 degrees and 250 degrees.

4. Braking system (6) according to any one of claims 1 and 2, in which the first circular portion (21) extends over a first angular range (a), the second circular portion (24) extends over a second angular range (|3), the first angular range (a) is complementary to the second angular range (|3).

5. A braking system (6) according to any one of claims 1 to 4, wherein at least a portion of the first planar face (14) of the brake disc is covered by at least a first coating (34), the first coating (34) being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel.

6. A braking system (6) according to claim 5, wherein said material comprises one of copper, silver and gold.

7. Braking system (6) according to any one of claims 5 and 6, wherein said first coating (34) has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 2 millimeters.

8. A braking system (6) according to any one of claims 5 to 7, wherein said first coating (34) is covered by a second coating (36).

9. A braking system (6) according to claim 8, wherein the second coating (36) comprises one of a steel or a cast iron material.

10. Braking system (6) according to any one of claims 8 and 9, wherein the second coating (36) has a thickness of between 1 millimeter and 3 millimeters, and preferably of between 1 millimeter and 1.5 millimeters.

11. Braking system (6) according to any one of claims 1 to 10, which comprises two inductors (22, 26) and a support bracket (38) suitable for carrying said inductor (22, 26); said support bracket comprising a first (40) and a second (42) support plate each carrying an inductor (22, 26), the first support plate (40) being arranged opposite at least a portion of the first flat face (14) of the brake disc, and the second support plate (42) being arranged opposite a portion of the second flat face (16) of the brake disc, the first support plate and the second support plate being fixed to each other.

12. Braking system (46) according to claim 1, wherein the first circular portion (50) is delimited by an internal radius (RII), an external radius (RE1) and a center (0) located on the axis of rotation (AA), the second circular portion (54) is delimited by an internal radius (RI2), an external radius (RE2), and a center (0) located on the axis of rotation (AA); and wherein the internal radius (RII) of the first circular portion (50) is greater than or equal to the external radius (RE2) of the second circular portion (54).

13. Braking system (46) according to claim 12, in which only a portion of the first flat face of the brake disc is covered with a first coating (34), said portion having the shape of a crown having an outer radius substantially equal to the outer radius (RE2) of the second circular portion, the first coating (34) being made of a material having an electromagnetic conductivity greater than the electromagnetic conductivity of steel.

14. The braking system (46) of claim 13, wherein said material comprises one of copper, silver, and gold.

15. A braking system (46) according to any one of claims 13 and 14, wherein said first coating (34) has a thickness of between 1 millimeter and 3 millimeters, and preferably between 1 millimeter and 2 millimeters.

16. Vehicle comprising a body (2), a hub (4) fixed and movable in rotation relative to the body, characterized in that it comprises a braking system according to any one of claims 1 to 15, the brake disc (8) being integral in rotation with the hub (4), said pad support (10) being carried by the body and the first support plate (40) being fixed to the body.

17. Braking method implemented by a braking system according to any one of claims 1 to 15 which comprises the following steps; - receiving a braking command: - supplying the at least one inductor of an electromagnetic retarder (22, 26; 52); - applying said at least one brake pad (12) against the brake disc (8).

Images