C-shaped flow channel magnetorheological brake with built-in exciting coil

Abstract

The application discloses a C-shaped flow channel magnetorheological brake with a centrally-arranged excitation coil and belongs to the technical field of mechanical braking. The brake mainly comprises three parts of a magnetorheological braking component, magnetorheological fluid and an excitation coil. The upper end of a contact shaft (6) is connected with a contact shaft sleeve (1) through screw threads, the lower end of the contact shaft is arranged on a braking surface in a cavity formed by a base (4) and an upper end cover (3), the gap between the cavity formed by the upper end cover (3) and the base (4) and the contact shaft (6) is filled with magnetorheological fluid (7), and the excitation coil is arranged in a cavity formed by the base (4) and a lower end cover (5). The magnetorheological brake has the centrally-arranged excitation coil and a C-shaped flow channel around the coil, can effectively increase the turn volume ratio of the excitation coil and the length of the force arm of the braking surface, makes the magnetorheological material output a greater damping torque, improves the torque volume ratio and response speed of the magnetorheological brake, and has the advantages of simple and compact structure, low processing difficulty and suitability for miniaturization.

Description

Technical Field

[0001] This invention relates to the field of magnetorheological brake technology, specifically to the principle and design method of a C-type flow channel magnetorheological brake with a centrally located excitation coil, belonging to the field of mechanical braking technology. Background Technology

[0002] Magnetorheological fluid (MRF) is a novel type of intelligent fluid, primarily composed of a base fluid and magnetic particles suspended within it. When subjected to a working magnetic field, MRF undergoes a rheological effect within milliseconds, reversibly transforming from a liquid to a near-solid state. Applying MRF to mechanical braking systems allows for precise control of the damping torque of the braking system by altering the strength of the working magnetic field through control of the excitation coil current, thereby affecting the MRF's rheological properties.

[0003] Magnetorheological brakes are a novel braking component that integrates magnetic field control technology, mechanical braking technology, and magnetorheological material technology. Traditional brakes rely on friction between different mechanical components to dissipate the energy of the object being braked. In contrast, magnetorheological brakes use magnetorheological fluid as a medium, utilizing the magnetorheological effect induced by a magnetic field to generate a damping torque for braking. This results in less friction and wear on the brake shaft or brake disc, and offers advantages such as simple control and rapid response. While magnetorheological brakes exhibit superior response and control characteristics compared to traditional brakes, they suffer from a lower torque-to-volume ratio and a more complex structure.

[0004] Currently, there are roughly three methods to improve the torque-to-volume ratio of magnetorheological brakes: first, by increasing the turns-to-volume ratio of the excitation coil to improve the magnetic field utilization of the magnetorheological brake; second, by increasing the contact area of ​​the braking surface; and third, by increasing the lever arm length of the main braking surface. Since a smaller inner and outer diameter of the excitation coil results in a smaller volume for the same number of turns, the first method requires reducing the inner and outer diameters of the excitation coil. However, traditional magnetorheological brakes use a structure where the excitation coil wraps around the braking component, which limits the inner and outer diameters of the excitation coil, making it difficult to reduce them. The second method has many implementation methods. The third method requires increasing the distance between the main braking surface and the central axis. Through research and analysis, a novel magnetorheological brake structure was designed, changing the layout of the excitation coil and placing it within a C-shaped magnetorheological flow channel. This simultaneously increases the magnetic field utilization of the magnetorheological brake and the lever arm length of the main braking surface, generating higher torque output per unit volume.

[0005] Patent search revealed the following known technical solution: Application No.: CN201710202425.4, Application Date: 2017.03.30, Authorization Announcement Date: 2018.11.27. This invention relates to a Y-type brake disc magnetorheological brake, which places three coils in the left outer shell, right outer shell and middle cylinder respectively. After applying current in the same direction to the three excitation coils, the three excitation coils form a large magnetic circuit. The placement of the coils can increase the generated magnetic field strength, thereby increasing the braking torque of the brake.

[0006] The aforementioned patent increases the output torque of the brake by increasing the number of excitation coils, but its excitation coils are side-mounted ring coils with a small turns-to-volume ratio and a large number of coils, resulting in a complex structure of the magnetorheological brake, which is not conducive to the miniaturization of the brake and the improvement of the torque-to-volume ratio.

[0007] Patent searches revealed the following known technical solutions: Application No.: CN201410111419.4, Application Date: March 24, 2014, Authorization Announcement Date: August 17, 2016. This invention discloses a high-efficiency magnetorheological braking device, mainly comprising an excitation coil, a rotating shaft, a left end cover, a right end cover, bolts, a magnetic shielding ring, a sealing ring, a braking cylinder, a keyway, and bearings. It is a multi-cylinder structure magnetorheological brake. This invention reduces braking time and the large amount of heat generated during braking through indirect braking via a two-stage reduction mechanism.

[0008] The aforementioned patent solves the overheating problem of magnetorheological brakes during braking. It also improves the sensitivity of magnetorheological brakes and reduces braking time by increasing the contact disc area. However, the complex structure and large size of its braking components result in a small internal excitation coil volume and low magnetic field strength. The technical problem of insufficient torque-to-volume ratio of the magnetorheological brake still exists.

[0009] The above search results show that the above technical solutions do not affect the novelty of the present invention; and the combination of the above patent documents does not destroy the inventiveness of the present invention. Summary of the Invention

[0010] To address the aforementioned problems, this invention discloses a C-type flow channel magnetorheological brake with a centrally located excitation coil. The technical problem to be solved is the insufficient torque-to-volume ratio of the magnetorheological brake. This actuator has the following advantages: (1) small structural size; (2) large torque-to-volume ratio; (3) fast response speed; (4) mature manufacturing process and simple and easy-to-implement working principle; (5) reliable operation and strong applicability.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] This invention discloses a C-type flow channel magnetorheological brake with a centrally located excitation coil, having an outer diameter of Φ23mm. It mainly consists of three parts: a magnetorheological braking component, a magnetorheological fluid, and an excitation coil. The magnetorheological braking component includes a contact shaft sleeve (1), a deep groove ball bearing (2), an upper end cover (3), a base (4), a lower end cover (5), and a contact shaft (6). The contact shaft (6) is placed in the cavity formed by the upper end cover (3) and the base (4), and the gap between the cavity formed by the upper end cover (3) and the base (4) and the contact shaft (6) is filled with magnetorheological fluid (7). The excitation coil (8) is placed in the cavity formed by the base (4) and the lower end cover (5).

[0013] The C-type flow channel magnetorheological brake with the excitation coil in the center generates a working magnetic field after a control current is applied to the excitation coil. The magnetic field passes through the C-type flow channel inside the brake, causing the magnetorheological fluid inside to undergo a rheological effect, thereby applying a damping torque to the contact shaft and reducing the contact shaft speed.

[0014] Beneficial effects

[0015] 1. The C-type flow channel magnetorheological brake with a centrally located excitation coil disclosed in this invention adopts a centrally located excitation coil layout, which improves the turns-to-volume ratio of the excitation coil. Under the same volume and current, the excitation coil can provide a stronger working magnetic field, enabling the magnetorheological material to provide a larger damping torque.

[0016] 2. The C-type flow channel magnetorheological brake with a centrally located excitation coil disclosed in this invention adopts a C-type flow channel design, which increases the lever arm length and contact area of ​​the main braking surface of the contact shaft, resulting in a high torque-to-volume ratio and fast response speed.

[0017] 3. Magnetorheological fluids exhibit rheological effects under the influence of a magnetic field, with a rapid response speed on the order of milliseconds.

[0018] 4. Compared with traditional brakes, the present invention is small in size, simple and compact in structure, easy to manufacture, and suitable for miniaturization. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a C-type flow channel magnetorheological brake with the excitation coil in the middle.

[0020] Among them: 1-contact shaft sleeve, 2-deep groove ball bearing, 3-upper end cover, 4-base, 5-lower end cover, 6-contact shaft, 7-magnetorheological fluid, 8-excitation coil. Detailed Implementation

[0021] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.

[0022] Example 1:

[0023] This embodiment describes a C-type flow channel magnetorheological brake with the excitation coil in the center, such as... Figure 1 As shown, it mainly consists of three parts: a magnetorheological braking component, a magnetorheological fluid, and an excitation coil.

[0024] The upper end of the contact shaft (6) is connected to the contact shaft sleeve (1) by a thread. The lower end of the contact shaft is placed in the cavity formed by the base (4) and the upper end cover (3). Magnetorheological fluid (7) fills the cavity formed by the base, the upper end cover and the gap between the contact shaft. The upper end cover has a circular through hole for draining or adding magnetorheological fluid. The braking surface of the contact shaft includes two disc-shaped braking surfaces and two annular braking surfaces. The two annular braking surfaces parallel to the central axis have a larger working area and lever arm length than the disc-shaped braking surfaces and are the main braking surfaces. The lever arm length of the annular braking surfaces is close to the outer radius of the brake and has high torque output efficiency. The deep groove ball bearing (2) is sleeved on the upper end of the contact shaft and installed in the groove of the upper end cover (3) to support the rotation and limit the position of the contact shaft.

[0025] The base adopts a C-shaped flow channel, and a groove is provided at the lower end of the base. An excitation coil (8) is installed in the cavity formed by the base and the lower end cover (5), and the excitation coil is placed in the C-shaped flow channel. After the excitation coil is turned on, it generates a working magnetic field. The working magnetic field passes through the magnetorheological fluid, causing the magnetorheological fluid to undergo a rheological effect. The damping torque of the magnetorheological fluid on the contact shaft increases, thereby reducing the rotational speed of the contact shaft and achieving a braking effect.

[0026] Finally, it should be noted that the above detailed description further elaborates on the purpose, technical solution, and beneficial effects of the invention, with the aim of helping to further understand the invention. It should be understood that the above description is only a specific embodiment of the invention and is not intended to limit the scope of protection of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A magnetorheological brake of the C-channel type with centrally located field coils, characterized in that: The magnetorheological brake includes a magnetorheological brake component, a magnetorheological fluid and an excitation coil; the magnetorheological brake component includes a contact shaft sleeve, a deep groove ball bearing, an upper end cover, a base, a lower end cover and a contact shaft, the upper end cover is processed with a circular through hole for discharging or adding the magnetorheological fluid, the deep groove ball bearing is sleeved on the upper end of the contact shaft for supporting the rotation and limiting the contact shaft, the deep groove ball bearing is installed in the groove of the upper end cover, the upper end of the contact shaft is connected with the contact shaft sleeve through screw threads, the lower end brake surface of the contact shaft is arranged in the cavity formed by the base and the upper end cover, the magnetorheological fluid is filled in the gap between the cavity formed by the base and the upper end cover and the contact shaft, the base adopts a C-shaped flow channel, the lower end is provided with a groove, the excitation coil is installed in the cavity formed by the base and the lower end cover, the excitation coil is arranged in the C-shaped flow channel, so that the working magnetic field generated after the excitation coil is electrified passes through the magnetorheological fluid, when the magnetorheological fluid is stimulated to generate rheological effect by the working magnetic field, the disc type brake surface and the ring type brake surface at the lower end of the contact shaft are acted on by the damping torque of the magnetorheological fluid, the ring type brake surface is the main brake surface for outputting the main damping torque, so that the rotation speed of the contact shaft is reduced.

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