Permanent magnet eddy current brake relief state switching method

Abstract

The present invention provides a permanent magnet eddy current brake relief state switching method, which is used for the state switching control of the permanent magnet eddy current brake system of rail transit, wherein the permanent magnet eddy current brake system includes a permanent magnet, an action mechanism, a protective plate, etc.; the switching method includes the following steps: in the relief state: adjusting the permanent magnet away from the track to weaken the air gap magnetic field between the permanent magnet and the track to the design requirement; in the braking state: adjusting the permanent magnet close to the track to a predetermined position to enhance the air gap magnetic field between the permanent magnet and the track. A method for permanent magnet eddy current braking and relief in the field of rail transit with automatic control and simple structure is proposed, which provides technical support for the application of permanent magnet eddy current brakes in the field of rail transit.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit, and in particular to a method for switching a brake relief state suitable for permanent magnet eddy current braking of rail transit. Background Art

[0002] As a new non-adhesive braking method, eddy current braking has attracted widespread attention for its superior braking performance and non-wear characteristics. Eddy current braking can be divided into electromagnetic eddy current braking and permanent magnet eddy current braking. Compared with electromagnetic eddy current braking, permanent magnet eddy current braking has two main advantages: no excitation power supply is required, which is energy-saving and environmentally friendly; no power supply is required, and there is no risk of brake failure when the power is off.

[0003] Electromagnetic eddy current can switch between braking and release states by energizing and de-energizing the brake. However, due to the self-excitation of the permanent magnet, if no corresponding measures are taken in the non-braking state, braking force will still be generated during the operation of the vehicle, thus affecting the operation of the vehicle. Therefore, it is necessary to design a set of action mechanisms to achieve the switching of the brake release state of the permanent magnet eddy current brake.

[0004] To achieve the switching of the braking and relief states of the permanent magnet eddy current brake, the source of the eddy current must be eliminated. According to the principle of eddy current generation, there are three main ways: first, "eliminate" the field source, that is, no magnetic lines of force pass through the track, and the permanent magnet is magnetically short-circuited; second, there is no relative motion, and the relative stillness of the permanent magnet and the track is achieved; third, the permanent magnet and the track are "separated".

[0005] At present, there is no device for switching the permanent magnet eddy current braking state in the field of rail transportation. Chinese patent CN108430149B discloses a permanent magnet magnetic field adjustment device and a permanent magnet magnetic field adjustment method, which relates to the field of particle accelerators and is used to generate an adjustable uniform magnetic field. The patent achieves magnetic short circuit of the permanent magnet by adding magnetic conductive materials to the corresponding parts of the permanent magnet, but the structure is complex, the degree of automation is low, and the magnetic field cannot be completely shielded. Summary of the invention

[0006] The object of the present invention is to provide a method for switching the brake relief state of a permanent magnet eddy current brake which has a simple structure and is easy to operate.

[0007] In order to achieve the above object, in some embodiments of the present invention, the following technical solutions are provided:

[0008] A permanent magnet eddy current brake relief state switching method is used for state switching control of a permanent magnet eddy current brake system of rail transit, wherein the permanent magnet eddy current brake system includes a permanent magnet, an action mechanism, a protective plate, etc.

[0009] The switching method comprises the following steps:

[0010] In remission:

[0011] Adjust the permanent magnet away from the track to weaken the air gap magnetic field between the permanent magnet and the track;

[0012] In braking state:

[0013] Adjust the permanent magnet close to the track to enhance the air gap magnetic field between the permanent magnet and the track.

[0014] In some embodiments of the present invention, the method of weakening and enhancing the air gap magnetic field between the permanent magnet and the track includes:

[0015] An opening and closing mechanism is arranged between the permanent magnet and the track. When the air gap magnetic field between the permanent magnet and the track is weakened, the opening and closing mechanism is closed. When the air gap magnetic field between the permanent magnet and the track is strengthened, the opening and closing mechanism is opened.

[0016] In some embodiments of the present invention, the opening and closing mechanism includes: a first side protection plate and a second side protection plate, the first side protection plate and the second side protection plate can be relatively opened and closed;

[0017] When the first side protection plate and the second side protection plate are controlled to open relatively, the air gap magnetic field between the permanent magnet and the track is enhanced;

[0018] When the first side protection plate and the second side protection plate are controlled to be relatively closed, the air gap magnetic field between the permanent magnet and the track is weakened.

[0019] In some embodiments of the present invention, the first side protective plate and the second side protective plate are both made of magnetic conductive materials, and the thickness of the first side protective plate and the second side protective plate satisfies that: when the protective plates are closed, the magnetic field on the track surface is close to the magnetic field of the open environment.

[0020] In some embodiments of the present invention, the method of weakening and enhancing the air gap magnetic field between the permanent magnet and the track includes:

[0021] Rotate the permanent magnet until its magnetizing direction is parallel to the track.

[0022] In some embodiments of the present invention, the method further comprises:

[0023] Arrange an annular magnetic yoke, and arrange the annular magnetic yoke around the periphery of the permanent magnet, wherein the annular magnetic yoke comprises a main body and an open end;

[0024] When the open end of the annular magnetic yoke is controlled to rotate to be opposite to the track, the air gap magnetic field between the permanent magnet and the track is enhanced;

[0025] When the main body of the annular magnetic yoke is controlled to rotate to be opposite to the track, the air gap magnetic field between the permanent magnet and the track is weakened.

[0026] In some embodiments of the present invention, the permanent magnet eddy current braking system further comprises:

[0027] Speed ​​sensor: used to detect the speed of the train;

[0028] Position sensor: used to detect the size of the air gap magnetic field between the permanent magnet and the track;

[0029] Controller: Receives speed data detected by the speed sensor, controls the permanent magnet to approach or move away from the track, and controls to weaken or open the air gap magnetic field between the permanent magnet and the track.

[0030] In some embodiments of the present invention, the controller further determines whether a braking level needs to be applied in combination with the travel speed of the train, and controls the distance between the permanent magnet and the track according to the braking level required.

[0031] In some embodiments of the present invention, the controller further controls the brake level as required to adjust the opening of the opening and closing mechanism.

[0032] In some embodiments of the present invention, the controller further performs brake level control according to needs to adjust the relative angle between the annular yoke opening and the track.

[0033] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0034] 1. Two permanent magnet eddy current braking and relief methods suitable for rail transit are proposed, providing technical support for the application of permanent magnet eddy current brakes in rail transit;

[0035] 2. Both methods can realize automatic control and have simple structure;

[0036] 3. Both methods can achieve multi-level braking force control by controlling the distance between the permanent magnet and the track and the opening degree;

[0037] 4. It has high degree of development and strong applicability. Depending on the drive structure and brake, different structures can be designed according to different application scenarios and fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0039] Figure 1 The schematic diagram of the first implementation structure mitigation structure is shown;

[0040] Figure 2 This is a schematic diagram of the first implementation structure brake structure;

[0041] Figure 3 The schematic diagram of the mitigation structure for the second implementation structure is shown;

[0042] Figure 4 It is a schematic diagram of the second implementation structure brake structure;

[0043] Figure 5 This is a flow chart of brake application control of the present invention;

[0044] In the above figures:

[0045] 1-Permanent magnet;

[0046] 2-Track

[0047] 3- yoke;

[0048] 4- first side protection plate;

[0049] 5- Second side protection plate;

[0050] 6- Magnetization direction of permanent magnet;

[0051] 7- Housing. DETAILED DESCRIPTION

[0052] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] It should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0054] A permanent magnet eddy current brake relief state switching method is used for state switching control of a permanent magnet eddy current brake system of rail transit.

[0055] The structure of the permanent magnet eddy current brake system includes permanent magnets, actuating mechanisms, protective plates, etc. The braking force is applied through the magnetic field between the permanent magnets and the track.

[0056] A braking relief state switching method, which is used to control the application and relief of magnetic braking force between a permanent magnet and a track, comprises the following steps:

[0057] In remission:

[0058] Adjust the permanent magnet 1 away from the track 2 to weaken the air gap magnetic field between the permanent magnet 1 and the track 2;

[0059] In braking state:

[0060] The permanent magnet 1 is adjusted to be close to the track 2 to enhance the air gap magnetic field between the permanent magnet 1 and the track 2 .

[0061] In order to achieve the above adjustment purpose, the permanent magnet 1 needs to be installed on the lifting mechanism. When the distance between the permanent magnet 1 and the track 2 needs to be adjusted, the lifting mechanism is controlled to move and the permanent magnet 1 is controlled to move up and down. When the permanent magnet 1 is close enough to the track, a sufficiently strong air gap magnetic field is generated between the permanent magnet 1 and the track to generate a magnetic braking force.

[0062] Two methods of weakening and strengthening the air gap magnetic field between the permanent magnet 1 and the track 2 are further provided.

[0063] The first implementation method, structure reference Figure 1 and Figure 2 .

[0064] In some embodiments of the present invention, the method of weakening and strengthening the air gap magnetic field between the permanent magnet 1 and the track 2 includes:

[0065] An opening and closing mechanism is provided between the permanent magnet 1 and the track 2. When the air gap magnetic field between the permanent magnet 1 and the track 2 is weakened, the opening and closing mechanism is closed. When the air gap magnetic field between the permanent magnet 1 and the track 2 is strengthened, the opening and closing mechanism is opened.

[0066] The opening and closing mechanism can form an opening. When the opening is open, the magnetic force lines of the permanent magnet 1 can pass through the opening and act on the track 2. When the opening is closed, the transmission path between the magnetic force lines and the track 2 is closed. The application of the magnetic braking force is controlled by opening and closing the opening.

[0067] In this implementation structure, the permanent magnet magnetization direction 6 is always perpendicular to the track 2 and upward. The yoke 4 is arranged on the upper part of the permanent magnet 1. The yoke 4 can be made of magnetic conductive material or non-magnetic conductive material according to the arrangement of the permanent magnet 2 of the permanent magnet eddy current brake.

[0068] As an implementation form of the opening and closing mechanism, in some embodiments of the present invention, the opening and closing mechanism includes: a first side protection plate 4 and a second side protection plate 5, the first side protection plate 4 and the second side protection plate 5 can be relatively opened and closed;

[0069] When the first side protection plate 4 and the second side protection plate 5 are controlled to open relatively, the air gap magnetic field between the permanent magnet 1 and the track 2 is enhanced;

[0070] When the first side protection plate 4 and the second side protection plate 5 are controlled to be relatively closed, the air gap magnetic field between the permanent magnet 1 and the track 2 is weakened.

[0071] As shown in the accompanying drawings, in this embodiment, the first side protection plate 4 and the second side protection plate 5 are both L-shaped, arranged opposite to each other, and are respectively installed on the rotating mechanism. By controlling the rotation of the first side protection plate 4 and the second side protection plate 5, the opening between the two protection plates is adjusted. The protection plate mechanism and the permanent magnet 1 are installed together on the lifting mechanism and can be lifted and lowered synchronously. The permanent magnet 1 is located in the enclosed space formed by the two protection plates. The execution control mechanism can control the rotation of the protection plate.

[0072] In some embodiments of the present invention, the first side protection plate 4 and the second side protection plate 5 are both made of magnetic conductive materials, and the thickness of the first side protection plate and the second side protection plate satisfies that when the protection plates are closed, the magnetic field on the track surface is close to the open environment magnetic field, reaching a short circuit state.

[0073] In the braking state, the first side protection plate 4 rotates to the left, and the second side protection plate 5 rotates to the right, and the opening between the two is opened. At the same time, the action mechanism drives the permanent magnet 1 to descend, so that the air gap between the permanent magnet 1 and the track 2 is reduced to the set value, and the air gap magnetic field between the permanent magnet 1 and the track 2 is enhanced. At this time, the permanent magnet 1 and the track 2 are facing each other, and the magnetic lines of force generated by the permanent magnet 1 pass through the track, generating eddy currents during the movement of the vehicle body, and then generating braking force. At the same time, the requirements of different levels of braking force are achieved by controlling the size of the air gap between the permanent magnet 1 and the track 2.

[0074] In the relief state, the actions are opposite, the first side protection plate 4 and the second side protection plate 5 are closed, and the permanent magnet 1 rises to weaken the air gap magnetic field. Specifically, at this time, the magnetic lines of force generated by the permanent magnet 1 form a magnetic short circuit with itself through the protection plate, and no magnetic lines of force pass through the track 2, so no eddy current is generated, and no braking force is generated. At the same time, under the control of the action mechanism, the air gap between the protection plate and the track 2 has a certain height and remains constant, preventing the friction between the track and the protection plate caused by bumps during the movement of the vehicle.

[0075] In addition, in the relief state, the protective plate is closed, which can protect the permanent magnet 1 and prevent ferromagnetic materials from being adsorbed to the permanent magnet 1. At the same time, it prevents flying stones from hitting the permanent magnet, causing the performance of the permanent magnet to deteriorate, thereby affecting the braking performance.

[0076] The second implementation method, structure reference Figure 3 and Figure 4 .

[0077] In some embodiments of the present invention, the method of weakening and strengthening the air gap magnetic field between the permanent magnet 1 and the track 2 includes:

[0078] The permanent magnet 1 is rotated until the magnetization direction 6 of the permanent magnet is parallel to the track 2 .

[0079] In this embodiment, the permanent magnet 1 is not only installed on the lifting mechanism, but also installed on the rotating mechanism.

[0080] In the relief state, the vehicle runs normally, the magnetization direction 6 of the permanent magnet rotates to be parallel to the track, and the permanent magnet 1 is lifted to the set value. During the lifting process, the weak magnetic field of the permanent magnet is attenuated by the magnetic yoke and is opposite to the track. At this time, the magnetic density of the track surface is close to the ambient magnetic field, so no braking force is generated;

[0081] In the braking state, the permanent magnet is driven by the action mechanism to rotate the permanent magnet 1 90° counterclockwise or clockwise (depending on the direction of the relief state), and the magnetization direction of the permanent magnet 1 rotates to be perpendicular to the track 2. At the same time, the permanent magnet 2 is lowered to the set distance from the track so that the strong magnetic field is facing the track, thereby generating the braking force required for braking.

[0082] In some embodiments of the present invention, the method further comprises:

[0083] An annular yoke 4 is provided to surround the permanent magnet, and the annular yoke 4 comprises a main body and an open end. The yoke can also be made of a magnetic conductive material or a non-magnetic conductive material according to the arrangement of the permanent magnets of the permanent magnet eddy current brake.

[0084] When the open end of the annular magnetic yoke 4 is controlled to rotate to be opposite to the track, the air gap magnetic field between the permanent magnet 1 and the track 2 is enhanced;

[0085] When the main body of the annular yoke 4 is controlled to rotate to be opposite to the track, the air gap magnetic field between the permanent magnet 1 and the track 2 is weakened.

[0086] In this implementation structure, the annular yoke 4 is mounted on a rotating mechanism that is independent of the rotating mechanism of the permanent magnet 1, and the position of the opening of the annular yoke 4 determines whether the magnetic lines of force can pass through the yoke 4 and act on the track 2. When the opening is completely or partially opposite to the track 2, the air gap magnetic field between the permanent magnet 1 and the track 2 can be enhanced.

[0087] In the braking state, the permanent magnet is driven by the rotating action mechanism, the magnetization direction of the permanent magnet 1 rotates to be perpendicular to the track 2, and the yoke 4 is rotated at the same time until the opening is opposite to the track 2. At the same time, the permanent magnet 2 is lowered to a set distance from the track 2 so that the strong magnetic field is facing the track, thereby generating the braking force required for braking.

[0088] In the release state, the action is opposite, which will not be described in detail. At this time, the magnetic lines of force generated by the permanent magnet 1 form a magnetic short circuit with itself through the yoke 4, and no magnetic lines of force pass through the track 2, so no eddy current is generated, and no braking force is generated.

[0089] In some embodiments of the present invention, the permanent magnet eddy current braking system further comprises:

[0090] Speed ​​sensor: used to detect the speed of the train;

[0091] Position sensor: used to detect the relative position between the permanent magnet and the track;

[0092] Controller: Receives speed data detected by the speed sensor, controls the permanent magnet to approach or move away from the track, and controls to weaken or strengthen the air gap magnetic field between the permanent magnet and the track.

[0093] Specifically, the controller can control the lifting mechanism of the permanent magnet, the rotating mechanism of the permanent magnet, the rotating mechanism of the annular magnetic yoke, and the opening and closing control mechanism of the protective plate.

[0094] In some embodiments of the present invention, the controller further determines whether a braking level needs to be applied in combination with the travel speed of the train, and controls the distance between the permanent magnet and the track according to the required braking level.

[0095] The distance and effective area between the permanent magnet 1 and the track 2 can affect the strength of the air gap magnetic field, and further affect the braking level.

[0096] In some embodiments of the present invention, the controller further controls the brake level as required to adjust the opening of the opening and closing mechanism. When the brake level is high, the opening of the opening and closing mechanism is large, and when the brake level is low, the opening of the opening and closing mechanism is small. The opening of the opening and closing mechanism mentioned here refers to the size of the opening between the first side guard plate 4 and the second side guard plate 5.

[0097] In some embodiments of the present invention, the controller further controls the braking level as required to adjust the relative angle between the annular yoke opening and the track. The relative angle described here refers to the relative degree between the annular yoke and the track, which reflects the number of magnetic lines of force allowed to pass through. For example, if the opening is completely opposite to the track 2, all the magnetic lines of force can pass through, corresponding to a larger braking level. If the opening deviates from the central axis, some of the magnetic lines of force can pass through, corresponding to a smaller braking level.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A permanent magnet eddy current brake relief state switching method, used for state switching control of a permanent magnet eddy current brake system for rail transit, characterized in that: The permanent magnet eddy current braking system comprises a permanent magnet; The switching method comprises the following steps: In remission: Adjust the permanent magnet away from the track to weaken the air gap magnetic field between the permanent magnet and the track; In braking state: Adjust the permanent magnet close to the track to enhance the air gap magnetic field between the permanent magnet and the track; The permanent magnet eddy current braking system further comprises: Speed ​​sensor: used to detect the speed of the train; Position sensor: used to detect the relative position between the permanent magnet and the track; Controller: receives speed data detected by the speed sensor, and controls the permanent magnet to move closer to or farther from the track, thereby controlling the weakening or strengthening of the air gap magnetic field between the permanent magnet and the track; The controller further determines the braking level to be applied in combination with the travel speed of the train, and controls the distance between the permanent magnet and the track according to the braking level as required; An opening and closing mechanism is arranged between the permanent magnet and the track, wherein the opening and closing mechanism comprises: a first side protection plate and a second side protection plate, and the first side protection plate and the second side protection plate can be relatively opened and closed; The first side protection plate and the second side protection plate are both made of magnetic conductive material, and the thickness of the first side protection plate and the second side protection plate satisfies that: when the protection plates are closed, the magnetic field on the track surface is close to the magnetic field of an open environment.

2. The permanent magnet eddy current brake relief state switching method according to claim 1 is characterized in that: Methods for weakening and strengthening the air gap magnetic field between the permanent magnet and the track include: When the air gap magnetic field between the permanent magnet and the track is weakened, the opening and closing mechanism is closed, and when the air gap magnetic field between the permanent magnet and the track is strengthened, the opening and closing mechanism is opened.

3. The permanent magnet eddy current brake relief state switching method according to claim 2, characterized in that: When the first side protection plate and the second side protection plate are controlled to open relatively, the air gap magnetic field between the permanent magnet and the track is enhanced; When the first side protection plate and the second side protection plate are controlled to be relatively closed, the air gap magnetic field between the permanent magnet and the track is weakened.

4. The method for switching the permanent magnet eddy current brake relief state according to claim 2 or 3, characterized in that: The controller further controls the brake level as required to adjust the opening of the opening and closing mechanism.

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