Electrical protection device in braking systems

Abstract

The present invention relates to an electrical protection device in braking systems that comprises a ring with a plurality of stabilising perforations; a brush support having a first end and a second end, said brush support being arranged adjacent to the ring and connected to a discharge point; and a brush connected to the first end of the brush support, said brush being in contact with the ring. In accordance with the above, the ring is arranged on a face of a brake disc of the braking system, and said brush is configured to direct stray electric currents from the ring to the discharge point.

Description

[0001] ELECTRICAL PROTECTION DEVICE IN BRAKING SYSTEMS

[0002] TECHNICAL FIELD

[0003] This disclosure relates to electrical protection devices. Specifically, this disclosure relates to eddy current protection devices for protecting components in transmission systems, which may include electromagnetic braking systems.

[0004] DESCRIPTION OF THE STATE OF THE ART

[0005] Metrocables, also known as urban cable cars or cableways, are public transportation systems that use cabins suspended by overhead cables to move between stations. These systems have proven to be effective solutions for improving mobility in urban areas with particular topographical challenges. In recent years, passenger demand for this type of transportation has increased, and consequently, it has become necessary for their drive systems to be more robust, reliable, and powerful.

[0006] An example of this is cable car braking systems. These are components that ensure the safety and speed control of aerial vehicles traveling along the cables. The choice of braking system depends on several factors, including the cable car's operating speed, load capacity, terrain gradient, and safety requirements. Redundancy and backup systems are essential to ensure safety in the event of a component failure. Cable car braking systems are critical to passenger safety and the efficient operation of the system as a whole.

[0007] In accordance with the above, one of the braking systems that has been implemented in metro cables is electric brakes, also known as induction brakes, Faraday brakes, or eddy current brakes. An electric brake is a braking device that uses the electromotive force produced by induced currents or eddy currents in a conductive material when it is in a variable magnetic field, or when the conductive material itself moves in a magnetic field, to stop or hold a moving object in position.

[0008] Unlike conventional mechanical brakes, electric brakes have no parts in direct contact with the object being braked. This minimizes wear and prolongs the system's lifespan. However, the eddy currents used by this braking system transform useful forms of energy, such as kinetic energy, into unwanted heat, which can affect drive system components, for example, causing micro-abrasions on bearing raceways, melting metal surfaces, and / or degrading lubricants.

[0009] In accordance with the above, the state of the art discloses systems for counteracting eddy currents such as those disclosed in patent documents US 7,339,777 B2 and KR 101,876,087 Bl.

[0010] US 7,339,777 B2 describes a grounding system for a rotating shaft, specifically for applications in wind turbines. This system seeks to ground eddy currents passing through a mechanical power transmission shaft that includes: a frame defining a central opening for a rotating shaft, a plurality of grounding fibers secured within the frame, a plurality of fiber clamps positioned with the frame, a plurality of mounting brackets having mounting channels for the frame, and a plurality of installation guides, positioned on the plurality of mounting brackets. The fiber clamps act to urge the plurality of grounding fibers toward the central opening.

[0011] Mounting brackets are configured to be mounted to the motor housing with electrical grounding, such as through bolts and / or studs, and frame portions are retained within the frame mounting channels. Installation guides are configured to properly align the frame and grounding fibers relative to the motor's rotating shaft. KR 101,876,087 B1, for its part, discloses a device mounted on a DC motor that allows eddy currents from rolling elements to be directed to a grounding point to prevent EDM damage to bearings.

[0012] Such a device disclosed in KR 101,876,087 B1 includes: a cover assembly, a lower housing that is coupled to a lid of the cover assembly, a set of magnetic poles arranged in the cover assembly, an armature core with a plurality of coil ends that interact with the magnetic poles, and an armature that includes insulators arranged below and above the armature core, and a brush holder arranged within the housing that contains a brush in selective contact with the poles while they are in rotation.

[0013] However, these documents do not disclose devices that allow eddy currents in braking systems to be directed to prevent them from affecting other components of said systems, and that can also be installed or replaced without the need to disassemble or service the braking system.

[0014] BRIEF DESCRIPTION

[0015] The present disclosure relates to an electrical protection device in braking systems, comprising a ring with a plurality of stabilizing perforations; a brush holder with a first end and a second end, said brush holder being arranged adjacent to the ring and connected to a discharge point; and a brush connected to the first end of the brush holder, said brush being in contact with the ring.

[0016] According to the above, the ring is arranged on one face of a disc of the braking system, and said brush is configured to conduct electric currents from the ring to the discharge point. BRIEF DESCRIPTION OF THE FIGURES

[0017] FIG. 1 illustrates an electrical protection device in braking systems, comprising a ring with a plurality of stabilizing perforations, disposed on a brake disc; a brush holder disposed adjacent to the ring and connected to a frame.

[0018] FIG. 2 A illustrates a ring like that of FIG. 1, comprising an inner annular section and an outer annular section, wherein the inner annular section has a thickness less than the thickness of the outer annular section.

[0019] FIG. 2B illustrates a ring like that of FIG. 2A, wherein the ring is formed by a first arc and a second arc that are connected to each other, each of said arcs having two longitudinal ends, wherein a longitudinal end of the first arc has a pin, and a longitudinal end of the second arc has a hole into which said pin is inserted.

[0020] FIG. 3 illustrates an electrical protection device in braking systems like that of FIG. 1, in which a brush is connected to the first end of the brush holder. This brush is connected to a position controller.

[0021] FIG. 4 illustrates an electrical protection device in braking systems such as that of FIG. 3, wherein the brake disc is arranged on a shaft that is connected at one end to a motor and at the other end to a reducer.

[0022] DETAILED DESCRIPTION

[0023] The term “transportation system” refers to a coordinated set of components, infrastructure, vehicles, and technologies designed to move people or goods from one place to another. These systems are essential for connectivity and mobility in urban, regional, and global areas. Most transportation systems have a drive system that includes components such as axles, motors, and bearings, and use some type of braking system to control speed, stop when necessary, and ensure the safety of passengers and cargo. The variety of transportation systems and their specific requirements have led to the development of a wide range of braking technologies tailored to each application.

[0024] For example, a braking system may be an electric brake, also known as an induction brake, Faraday brake, or eddy current brake. An electric brake uses the electromotive force produced by induced currents or eddy currents in a conductive material when it is in a changing magnetic field, or when the conductive material itself moves in a magnetic field, to stop the conductive material.

[0025] However, these eddy currents, which create the effect of braking or reducing movement in the system, are also considered stray currents because they can affect the integrity of the traction and braking system. This is because eddy currents transform kinetic energy into unwanted heat, which can affect elements of the traction system, for example, causing micro-abrasions on bearing raceways, melting metal surfaces, and / or degrading lubricants.

[0026] Particularly when a drive system includes components such as a motor with bearings, eddy currents can cause an electroerosion effect on said bearings and increase their temperature. Bearing heating affects the efficiency and lifespan of the bearings, accelerating wear on the bearing surfaces. Furthermore, heating can also be related to lubrication problems; that is, if the quantity of lubricant is insufficient or the quality of the lubricant is inadequate, the bearing can heat up either due to the eddy current itself or due to a combination of the passage of the eddy current and excessive friction. All of this results in material detachment from the bearing, vibrations, degradation of the bearing lubricant, increased noise during motor operation, and ultimately, malfunction and failure of the motor.

[0027] According to the foregoing, the present disclosure relates to an electrical protection device in braking systems, comprising a ring (20) with a plurality of stabilizing perforations (21); a brush support (40) with a first end (41) and a second end (42), said brush support (40) is arranged adjacent to the ring (20) and connected to a discharge point; and a brush (50) connected at the first end (41) of the brush support (40), said brush (50) being in contact with the ring (20).

[0028] Said ring (20) is arranged on a face of a disc of the braking system, and said brush (50) is configured to conduct electric currents from the ring (20) to the discharge point.

[0029] Preferably, the disc is a brake disc (10), but it may also correspond to a ferrule or flywheel connected to the braking system. Hereinafter, only the term “brake disc (10)” will be mentioned, but the technical effects of the device of the present disclosure are applicable to any type of disc in which eddy currents flow.

[0030] Particularly, when the brake disc (10) is stopped by the action of the electromotive force generated by the induced currents or Foucault currents present in the brake disc (10), the brush (50) which is in contact with the ring (20) arranged on the brake disc (10), conducts the eddy currents from the ring (20) towards the brush support (40), preventing these currents from moving to other elements of the braking system and the traction system, and subsequently redirecting them towards the discharge point.

[0031] For the purposes of this disclosure, the discharge point shall be understood to be any point where the eddy currents of the brake disc (10) are conducted. Said discharge point is selected from the group consisting of: a ground point, a capacitor such as, for example, a battery, other equivalent current discharge systems known to a person moderately versed in the subject matter, or a combination of the above.

[0032] Also, for the understanding of the present disclosure, in transportation systems, the traction or rotation system refers to the set of parts, elements, mechanisms and devices that provide the force or impulse necessary to move and stop a vehicle. That is, the traction system indicated above generates and transmits movement and is connected to a braking system to stop said movement. For example, the traction system can be a system consisting of a motor (80) connected to a reducer (90) or it can include a motor that does not require a reducer. In one embodiment of the present disclosure, the reducer (90) can be connected to a traction system of an overhead cable transportation system.

[0033] The motor may be selected from the group consisting of alternating current motors (e.g. three-phase synchronous motors, synchronized asynchronous motors, motors with a permanent magnet rotor, single-phase motors, two-phase motors, motors with a wound auxiliary starter and with a capacitor), direct current motors (e.g. series excitation motors, parallel excitation motors, compound excitation motors), combustion engines, motors with a wound auxiliary starter, equivalent motors that are known to a person moderately versed in the art and combinations of the above.

[0034] Furthermore, the reducer (90) may be a speed reducer selected from the group consisting of: worm gear speed reducers, gear speed reducers, cycloidal reducers, planetary speed reducers, internal gear reducers, external gear reducers, equivalent reducers that are known to a person moderately versed in the matter and combinations of the above. Particularly, the brake disc (10) is an element of the braking system that is connected to an element of a traction system that is selected from the group consisting of: a motor (80), a reducer (90), a joint such as a cardan joint, and combination of the above. In addition, said brake disc (10) is configured with the braking system to allow braking of the traction system.For example, when a motor shaft (80) is connected to the brake disc (10), said braking system allows the speed of the brake disc (10) to be reduced or stopped and therefore, allows the speed of the motor shaft (80) to be reduced.

[0035] Such a braking system of the present disclosure may be an electric brake system as indicated above or an electromagnetic brake system. Both electric brakes and electromagnetic brakes employ electromagnetic fields, but electromagnetic brakes ultimately rely on friction, whereas electric brakes utilize the electromotive force generated by eddy currents directly. An eddy current creates a magnetic field that opposes the change in the magnetic field that created it, and thus eddy currents react against the source of the magnetic field. The stronger the applied magnetic field, or the greater the conductivity of the conductor, or the greater the relative speed of movement, the greater the eddy currents and opposing fields generated.

[0036] Unlike conventional mechanical brakes where brake pads are in direct contact with a brake disc, electric brakes do not have any parts in direct contact with the brake disc (10), which makes it possible to minimize wear on both the brake disc (10) and other components of the braking system, and therefore makes it possible to prolong its useful life. Another technical effect of the braking system of the present disclosure being an electric brake is to allow precise control of the braking force compared to other braking systems, because the stronger the applied magnetic field, or the greater the conductivity of the brake disc (10), or the greater the relative speed of movement, the greater the eddy currents and opposing fields generated, that is, the braking force.Furthermore, this type of brakes can have a rapid response since the braking force is applied almost instantaneously when the eddy currents are generated in the brake disc (10).

[0037] However, it is important to clarify that the device of the present invention can conduct eddy currents caused and originating from any source, which travel through a disc.

[0038] On the other hand, the ring (20) is an element with an external diameter and an internal diameter corresponding to a central perforation through which an axis of a traction system passes, such as, for example, the axis of a motor (80) or a reducer (90). Said ring (20) can be made of a conductive material and transfers the eddy currents from the brake disc (10) to the brush (50) and to the discharge point. Without this ring (20) the eddy currents would move towards elements of the traction system, such as bearings, and would generate heating and damage, such as those mentioned above.

[0039] Said ring (20) can have an external diameter smaller than the diameter of the brake disc (10), which allows its size and weight to be reduced, without reducing its capacity to conduct eddy currents towards the brush (50). In addition, the fact that the diameter of the ring (20) is smaller compared to the brake disc (10), makes it easier for the assembly and maintenance of said ring (20) to be carried out by only one operator, who can carry its weight. On the other hand, the fact that the ring (20) is in direct contact with the brake disc (10) ensures that the eddy currents are directed to the ring (20) and finally to the discharge point, and do not move towards other elements of the traction system. In addition, the fact that the ring (20) is the element that is in contact with the brush (50), prevents the brake disc (10) from rubbing against another element of the electrical protection device and becoming damaged or worn.

[0040] On the other hand, the ring (20) may be made of a different material than the brake disc (10), so that it is lighter and facilitates the conduction of eddy currents. Furthermore, with reference to FIG. 2A and FIG. 2B , and in accordance with the above, the ring (20) has a plurality of stabilizing perforations (21). Said stabilizing perforations (21) allow the weight of the ring (20) to be reduced, which facilitates its transport, and also facilitates its assembly on a brake disc (10). Additionally, said stabilizing perforations (21) are arranged around the ring (20) symmetrically and / or in such a way as to compensate for the weight generated or reduced due to the perforations or fixing elements required to connect the brake disc (10) with said ring (20).The above allows that, when the ring (20) rotates in a manner integral with the brake disc (10), the centroid of the ring (20) is the central point of the ring (20), which prevents eccentric stresses from being generated in the axis of a mechanism of the traction system such as, for example, the axis of a motor (80) that could cause a malfunction of the latter. If the above were not fulfilled and said stabilization perforations (21) were arranged asymmetrically in the ring (20), said ring (20) would have areas of greater weight, which would form unwanted radial stresses in the axis of a traction system that is connected to the brake disc (10).

[0041] On the other hand, the stabilization perforations (21) of the ring (20) can be oblong through perforations, which allows reducing the weight of the ring (20) and in turn prevents the torque required for the axis of the traction system to rotate from increasing considerably.

[0042] On the other hand, referring to FIG. 1, the electrical protection device in braking systems of the present disclosure may comprise a support disc (30), connected to a surface of the brake disc (10), wherein the ring (20) is connected to said support disc (30). The fact of including said support disc (30) allows the ring (20) to be replaced to put another one of other dimensions, without the need to make additional perforations or modifications to the brake disc (10).

[0043] In one embodiment of the present disclosure and referring to FIG. 2A and FIG. 2B , the ring (20) may comprise an inner annular section (22) and an outer annular section (23), wherein the inner annular section (22) has a thickness less than the thickness of the outer annular section (23). Accordingly, the inner annular section (22) may form a cavity, wherein the support disc (30) may engage with the ring (20). That is, the inner annular section (22) forms a cavity that may have a shape integral with the contour of the support disc (30), which allows said support disc (30) to be inserted into the inner annular section (22).

[0044] Additionally, and referring to FIG. 2B , the ring (20) may be formed by a first arch (24) and a second arch (25) that are connected to each other. The fact that the ring (20) is formed by different arches connected to each other, allows the different parts of the ring (20) to be installed on the brake disc (10) without the need to disassemble the braking system and the traction system. That is, the first arch (24) can be connected to the brake disc (10) and then, the second arch (25) can be connected.

[0045] The first arch (24) and the second arch (25) can be connected to each other by means of connection means selected from the group consisting of: screws, bolts, pin-wedges, bolts, nuts, rivets, studs, pins, wedges, clamps, pins, equivalent elements known to a person moderately versed in the subject or a combination of the above.

[0046] For example, referring again to FIG. 2B , when the ring (20) is formed by a first arch (24) and a second arch (25) that are connected to each other, each of said arches has two longitudinal ends, where a longitudinal end of the first arch (24) has a pin (27), and a longitudinal end of the second arch (25) has a hole (26) where said pin (27) is inserted. The fact that the first arch (24) and the second arch (25) of the ring (20) are connected by a pin (27) inserted into a hole (26) of one of said arches, is that it reduces the assembly time of the ring (20) on the brake disc (10), while ensuring that both arches are correctly aligned and do not unbalance the traction system. For its part, referring to FIG. 3, the brush (50) is a device that allows a sliding electrical connection to be established in rotating devices such as electric motors and generators.In particular, the brush (50) is in frictional contact with the ring (20). When the brake disc (10) rotates, and therefore the ring (20) also rotates, the brush (50) maintains electrical contact with the surface of the ring (20), allowing the flow of eddy currents from the brake disc (10) to the brush (50).

[0047] Said brush (50) also comprises a connection terminal (51) connected to the brush support (40). When the brake disc (10) is rotating and its speed is being reduced by the action of a brake exerted by the eddy currents, the resulting eddy electric currents that are transmitted to the ring (20) are conducted from the brush (50) towards the brush support (40) which is connected to the discharge point, by means of the connection terminal (51). Said connection terminal (51) can be an electrical conductor connected to the brush support (40).

[0048] On the other hand, and referring to FIG. 3, in one embodiment of the present disclosure, a second brush (52) can be connected at an intermediate point between the first end (41) and the second end (42) of the brush holder (40), wherein said second brush (51) is in contact with the ring (20). Referring to FIG. 3, the fact that a second brush (52) is connected to the brush holder (40) in contact with the ring (20), allows both the brush (50) that would correspond to a first brush (50), and the second brush (52) to conduct a greater amount of eddy currents from the brake disc (10) towards the discharge point, which reduces the eddy currents that are transmitted to the traction system.According to the above, having at least two brushes (50, 51) in contact with the ring (20) allows reducing the currents that enter the components such as bearings, which allows them not to suffer damage or overheat due to said currents, as explained above.

[0049] On the other hand, referring to FIG. 1, the brush holder (40) can be a bar made of an electrically conductive material, which allows the current to be transmitted from the brush (50) to a discharge point, and which has, as previously stated, a first end (41) adjacent to the ring (20) and a second end (42). The brush (50) is arranged at the first end (41) of said brush holder (40). According to the above, the brush (50) is located between the ring (20) and the brush holder (40), which allows the brush (50) to be in contact with the ring (20).

[0050] In one embodiment of the present disclosure, and referring to FIG. 3 , when the device of the present disclosure has a first brush (50) and a second brush (52), the brush holder (40) may be an elongated plate with a first section and a second section, where the first section has an arc shape, and the second section may have another different shape. When the brush holder (40) has said first section in the shape of an arc, at one point of the arc the first brush (50) is connected while at another point of said arc the second brush (52) is connected, and the second section of the brush holder (40) is connected to the discharge point.

[0051] On the other hand, and in accordance with any of the previously described embodiments, and with reference to FIG. 1, FIG. 3, and FIG. 4, the brush holder (40) can be connected to a structure (70) corresponding to the discharge point. The fact that the structure (70) corresponds to a discharge point provides a safe route for the current to flow to the ground when said discharge point corresponds to a ground point, avoiding the risk of electric shocks to operators.

[0052] Said structure (70) can be made of a conductive material, which allows the electric current that passes through the brush holder (40) to move towards the structure (70). In addition, said structure (70) can be arranged on a support surface, which allows the brush holder (40) connected to said structure (70), and the brush (50) itself to remain stable as the brake disc (10) and the ring (20) rotate. In said embodiment, and referring to FIG. 3, the brush holder (40) can be removably connected to the structure (70), which allows exchanging between different brush holders (40) to put others with other shapes, or to carry out changes of parts or maintenance according to the requirements.

[0053] The structure (70) may be made up of plates, sheets or plates, bars or profiles with a cross section in the shape of an I, a C shape, a T shape, profiles with a cross section with a shape that is selected from the group consisting of squares, triangles, circles, rectangles, pentagons, trapezoids, ellipses, rhombuses, hexagons, heptagons, octagons, decagons and combinations of the above.

[0054] Likewise, the material of the structure (70) is preferably a metal that can be selected from the group consisting of carbon steel, iron castings, galvanized iron, chromium steels, chromium-nickel steels, chromium-nickel-titanium steels, nickel-chromium-molybdenum-tungsten alloy, ferrous chromium-molybdenum alloys, 301 stainless steel, 302 stainless steel, 304 stainless steel, 316 stainless steel, 405 stainless steel, 410 stainless steel, 430 stainless steel, 442 stainless steel, manganese alloy steel, aluminum, materials permitted to be worked with food, and combinations of the above.

[0055] On the other hand, and referring to FIG. 3, the brush (50) can be connected to a position regulator (60), where said position regulator (60) exerts pressure on the brush (50) that ensures permanent contact between the brush (50) and the ring (20). Considering that the brush (50) is in contact with the ring (20) to conduct the eddy currents of the brake disc (10) to the discharge point. Said position regulator (60) allows that as the material of the brush (50) wears down due to friction with the ring (20), the brush (50) moves and gets closer to the ring (20) so that they are always in contact.

[0056] Said position regulator (60) may be a device made up of different elements such as a spiral spring configured to press and correctly position the brush (50) against the ring (20). Example

[0057] An electrical protection device was developed in electric braking systems with the following characteristics:

[0058] - A brake disc (10) with a diameter of 700mm;

[0059] - a ring (20) with 6 stabilizing perforations (21) having an oblong shape. Said ring (20) is formed by a first arch (24) and a second arch (25) that are connected to each other, each of said arches having two longitudinal ends; wherein a longitudinal end of the first arch (24) has a pin (27), and a longitudinal end of the second arch (25) has a hole (26) where said pin (27) is inserted;

[0060] - a brush holder (40) which is connected to a structure (70) corresponding to the discharge point. Said brush holder (40) corresponds to an oblong plate with a first end (41) and a second end (42), said brush holder (40) being arranged adjacent to the ring (20) and connected to the structure (70) corresponding to the discharge point;

[0061] - a graphite brush (50) with a connection terminal (51), connected to the brush holder (40), said brush (50) being in contact with the ring (20);

[0062] - a position regulator (60) using a spiral spring connected to the brush (50).

[0063] Said device allowed the eddy currents originating in the brake disc (10) when it stopped to be conducted to ground, that is to say to the structure (70), and in this way the eddy currents did not move towards other elements of the traction system, such as the bearings, causing damage due to heating or electroerosion.

[0064] It should be understood that this disclosure is not limited to the described and illustrated modalities, since as will be evident to a person skilled in the art, there are possible variations and modifications that do not depart from the spirit of the invention, which is only defined by the following claims.

Claims

CLAIMS 1. An electrical protection device in braking systems, comprising: a ring (20) with a plurality of stabilizing perforations (21); a brush support (40) with a first end (41) and a second end (42), said brush support (40) being arranged adjacent to the ring (20) and connected to a discharge point; and a brush (50) connected at the first end (41) of the brush support (40), said brush (50) being in contact with the ring (20); wherein the ring (20) is arranged on a face of a disc of the braking system, and wherein said brush (50) is configured to conduct electric currents from the ring (20) to the discharge point.

2. The device of Claim 1, wherein the ring (20) comprises an inner annular section (22) and an outer annular section (23), wherein the inner annular section (22) has a thickness less than the thickness of the outer annular section (23).

3. The device of Claim 2, wherein the disk is connected to a support disk (30), and said support disk (30) engages the inner annular section (22) of the ring (20).

4. The device of Claim 1, wherein the ring (20) is formed by a first arc (24) and a second arc (25) that are connected to each other, each of said arcs having two longitudinal ends; wherein a longitudinal end of the first arc (24) has a pin (27), and a longitudinal end of the second arc (25) has a hole (26) into which said pin (27) is inserted.

5. The device of Claim 1, wherein the stabilizing perforations (21) of the ring (20) are oblong through perforations.

6. The device of Claim 1, wherein a second brush (52) is connected at an intermediate point between the first end (41) and the second end (42) of the brush holder (40), said second brush (52) being in contact with the ring (20).

7. The device of Claim 1, wherein the brush (50) is connected to a position regulator (60), wherein said position regulator (60) exerts a pressure on the brush (50) that ensures permanent contact between the brush (50) and the ring (20).

8. The device of Claim 1, wherein the brush holder (40) is connected to a structure (70) corresponding to the discharge point.

9. The device of Claim 1, wherein the braking system is an electric brake and the disc is a brake disc (10).

10. The device of Claim 1, wherein the disc is connected to an element of a traction system that is selected from the group consisting of: a motor (80), a reducer (90), a joint such as a cardan joint, and a combination of the above.

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