A magnetorheological fluid step-by-step braking device

Abstract

The invention discloses a magnetorheological fluid step-by-step braking device, comprising a housing and an axle, wherein the housing is surrounded by front and rear bottom plates and side plates to form a cylindrical working chamber, the axle passes through the front and rear bottom plates and is arranged in the working chamber, and the axle is connected to the front and rear bottom plates respectively through bearings, and is characterized in that: a magnetorheological braking unit is arranged in the working chamber. The invention provides two braking structures. One is that a brake disc is arranged in a sealed chamber, and the brake disc is composed of a plurality of discs connected in sequence from large to small, and the combination of the plurality of discs increases the braking surface of the magnetorheological fluid, so that the magnetorheological fluid can be better contacted to strengthen the braking force after magnetic curing. The other is that a motor is used to control the pressurizing protrusion on the conveyor belt, and the pressurizing protrusion moves with the conveyor belt and is pressed onto the first pressurizing rod in sequence. After the first pressurizing rod is subjected to downward pressure, it pushes the pressurizing disc to wrap the brake disc, and its downward pressure makes the multi-stage brake disc stop rotating faster, thereby realizing the increase of the braking force, and is more suitable for new energy vehicles.

Description

Technical Field

[0001] The invention belongs to the field of automobile braking, and in particular relates to a magnetorheological fluid step-by-step braking device. Background Art

[0002] New energy vehicles (NEVs) use unconventional fuels as their power source (or conventional fuels with new onboard power units), integrating advanced technologies in vehicle power control and drive to create advanced technical principles, new technologies, and new structures. Currently, most NEVs still use traditional brakes, employing dry friction braking through physical clamping, which can significantly damage components.

[0003] Magnetorheological fluid (MRF) is widely used in aerospace, machining, construction, and medical fields due to its fast response (milliseconds), low energy consumption, easy control, excellent durability, wide operating temperature range, and long service life. These properties of MRF facilitate the manufacture of braking devices, but current MRF-based braking devices can only utilize its shear stress and generate relatively low braking force, thus failing to meet the braking requirements of large equipment such as new energy vehicles. Patent No. 201310007233.X discloses a MRF brake actuator for electric vehicles, belonging to the field of automotive manufacturing technology. The mechanism comprises, from the inside, a drive shaft, a brake disc, MRF, an outer shell, an electromagnetic coil, a connecting disc, and a support structure. The drive shaft and brake disc are connected by splines, transmitting torque to the wheels. The left and right shells are bolted together to form a single unit. The brake disc is placed parallel to the inner shell and filled with MRF. The electromagnetic coil is supported by an iron core and fixed by bolts evenly spaced on the support, forming a closed magnetic circuit in contact with the outer surface of the shell. The support structure is divided into left and right parts and is fixed to the vehicle body, transmitting the braking force to the vehicle body. Bolts support the electromagnetic coil and also secure the main brake structure. This invention's brake actuator has a simple and compact structure, with dimensions that meet vehicle requirements. It builds pressure in milliseconds and is easily adjustable, meeting the vehicle's braking strength requirements. Although this magnetorheological fluid brake actuator proposes adjusting the braking force by controlling the current, it does not provide a specific implementation plan. Therefore, it can be assumed that this magnetorheological fluid brake actuator does not have the ability to accurately adjust the braking force and braking mode. Summary of the Invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a magnetorheological fluid step-by-step braking device with large braking torque that can meet the braking strength requirements of vehicles.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is:

[0006] A magnetorheological fluid step-by-step braking device comprises a shell and an axle, wherein the shell is surrounded by front and rear bottom plates and side plates to form a cylindrical working chamber, the axle passes through the front and rear bottom plates and is arranged in the working chamber, and the axle is respectively connected to the front and rear bottom plates through bearings, a magnetorheological braking unit is provided in the working chamber, the magnetorheological braking unit comprises an arc-shaped magnetic isolation plate, a first coil, a sealed chamber, a magnetic isolation ring, a second coil and a brake disc, the arc-shaped magnetic isolation plate has two sections, which are symmetrically arranged on the inner side of the side plate, and a first gap is provided between the upper and lower ends corresponding to the two sections of the arc-shaped magnetic isolation plate; the first coil has two sections, which are symmetrically arranged on the inner side of the arc-shaped magnetic isolation plate in an arc-shaped structure, and a second gap is provided between the upper and lower ends corresponding to the two sections of the first coil; the sealed chamber is provided in a cavity surrounded by the two sections of the first coil, and the sealed chamber is formed by an arc-shaped magnetic isolation plate. A cavity for containing magnetorheological fluid is formed by a magnetic conductive plate, a rectangular magnetic isolation sealing plate and a circular magnetic isolation sealing plate. The arc-shaped magnetic conductive plate has two sections, which are symmetrically arranged on the inner side of the first coil, and a third gap is provided between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates; the rectangular magnetic isolation sealing plates have two pieces, which are respectively arranged between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates to seal the third gap; the circular magnetic isolation sealing plates have two pieces, which are respectively arranged at the front and rear ends of the two arc-shaped magnetic conductive plates, and the front and rear circular magnetic isolation sealing plates are respectively fixedly connected to the bottom plates at corresponding positions through the first connecting rod; the magnetic isolation ring, the second coil and the brake disc are arranged in the sealed cavity, the second coil is sleeved on the axle, the brake disc is sleeved on the second coil, and the magnetic isolation ring is sleeved on the axle and is respectively located between the second coil and the front and rear bearings.

[0007] As a further technical solution, the brake disc mentioned above is composed of a plurality of discs connected in sequence from large to small, and a flange is provided on the outer edge of each disc.

[0008] As a further technical solution, each of the above first intervals is provided with a group of transmission pressure mechanisms and a fixed plate, the transmission pressure mechanism is arranged on the outside of the fixed plate, and the fixed plate is fixedly connected to the left and right arc-shaped magnetic isolation plates; the transmission pressure mechanism includes a motor, a conveyor belt, a driving wheel and a plurality of driven components, the driving wheel and the plurality of driven components are arranged horizontally front and back, the driving wheel is arranged on the power output shaft of the motor, and the motor is fixedly connected to any arc-shaped magnetic isolation plate; each group of the driven components includes a driven wheel and a second connecting rod, the driven wheel The wheel is arranged on the second connecting rod, the second connecting rod is fixedly connected to any arc-shaped magnetic isolation plate, the conveyor belt is installed on the driving wheel and the driven wheel for rotation and transmission, and a pressure protrusion is provided on a transmission surface of the conveyor belt; an upper semi-ring pressure plate matching its curvature is provided just above each of the discs, and a lower semi-ring pressure plate matching its curvature is provided just below each of the discs, the upper semi-ring pressure plate and the lower semi-ring pressure plate are both located in a sealed cavity, and the inner edges of the upper semi-ring pressure plate and the lower semi-ring pressure plate are provided with grooves for embedding flanges. In a non-pressurized state, the upper semi-ring pressure plate The lower half-ring pressure plate and the corresponding disc maintain the same first downward pressure distance. After pressurization, the disc is embedded in the annular structure formed by the combination of the corresponding upper half-ring pressure plate and the lower half-ring pressure plate; the top of the upper half-ring pressure plate and the bottom of the lower half-ring pressure plate are respectively fixedly connected to the pressure assembly, and the pressure assembly includes a pressure rod and a return spring, and the pressure rod is connected by a first pressure rod with a larger diameter and a second pressure rod with a smaller diameter. The first pressure rod is located between the conveyor belt and the fixed plate and can be moved up and down to be clamped on the fixed plate. The first pressure rod The top is set as an inclined structure in the front-to-back direction. In the pressurized state, the pressure protrusion of the conveyor belt is pressed against the inclined structure of the first pressure rod; the second pressure rod passes through the rectangular magnetic isolation sealing plate and is connected to the corresponding upper half-ring pressure plate or the lower half-ring pressure plate. The reset spring is located between the fixed plate and the rectangular magnetic isolation sealing plate and is installed on the second pressure rod. The lower part of the reset spring is fixedly connected to the rectangular magnetic isolation sealing plate; the second pressure rod is also provided with a circle of annular limit blocks. When not in the pressurized state, the annular limit blocks abut against the inner side of the rectangular magnetic isolation sealing plate.

[0009] As a further technical solution, the distance that the above-mentioned pressure protrusion pushes the first pressure rod downward is not greater than the first downward distance.

[0010] As a further technical solution, the diameter of the first pressure rod is larger than the diameter of the return spring.

[0011] As a further technical solution, the above-mentioned first pressure rod is clamped to the fixed plate by an elastic clamping assembly which can move up and down. The fixed plate is provided with an inner cavity. The elastic clamping assembly is respectively arranged in the inner cavities on the left and right sides of the first pressure rod. The elastic clamping assembly is horizontally connected in sequence by a telescopic rod, a limit spring and a positioning rod. One end of the telescopic rod extends from the inner cavity. The first pressure rod is overlapped on the protruding ends of the two telescopic rods, and the overlapping surfaces are set to mutually matching inclined structures. The positioning rod is fixedly connected to the inner cavity wall.

[0012] As a further technical solution, a curved heat dissipation pipe is provided between the front and rear base plates and the corresponding circular magnetic isolation sealing plates. One end of the heat dissipation pipe is provided on the side plate of the shell, and the other end of the pipe is connected by a connecting pipe.

[0013] As a further technical solution, the first coil and the second coil are both controlled by a coil current control module, which includes an external controller, a control circuit, and an output circuit including the first coil and the second coil. The external controller is electrically connected to the input end of the control circuit, and the output end of the control circuit is electrically connected to the output circuit. The external controller adopts a PLC or a microcontroller.

[0014] As a further technical solution, the control circuit includes a power supply VCC, a three-terminal voltage regulator U2, a capacitor C1, a capacitor C2, a chip, and resistors R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10. The three-terminal voltage regulator U2 adopts AMS1117-5v, and the chip adopts L9349LF. The 3rd pin (i.e., the VIN pin) of the three-terminal voltage regulator U2 is connected to the power supply VCC, and the three The 2nd pin of the three-terminal voltage regulator U2 (i.e., the VOUT (TAB) pin) is connected to the VS pin of the chip, and the capacitors C1 and C2 are connected between the 2nd pin (i.e., the VOUT (TAB) pin) and the 1st pin (i.e., the ADJ (GND) pin) of the three-terminal voltage regulator U2; the 4 outputs OUT1, OUT2, OUT3, and OUT4 of the chip correspond to PIN2, PIN9, PIN12, and PIN19 respectively, and the resistors R1, R2, R5, and C1 are directly connected in series with the output channels. Resistor R6 is used for output current sampling. The channel current positive feedback and channel current negative feedback derived from its two ends are connected to the ADC of the external controller to sample the output current data. The control signal inputs corresponding to the 4 outputs are IN1, IN2, IN3, and IN4, and the corresponding pins are PIN17, PIN14, PIN7, and PIN4. The external controller inputs the PWM control signal by connecting to the input pins. Resistors R3, R4, R7, and R8 are pull-down resistors at the signal input end. One end of the pull-down resistor is connected to the control signal input end and the other end is grounded. The EN end, that is, PIN16, is the enable end of the chip, that is, high level is valid. When the external controller outputs a high level, the chip function is activated. R9 is the pull-down resistor at the EN end, connected between EN and GND, and the resistance value is the same as that of the four pull-down resistors R3, R4, R7, and R8. PIN1, PIN10, PIN11, PIN15, PIN20, and PIN21 are circuit grounds.

[0015] As a further technical solution, the above-mentioned output circuit includes capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, freewheeling diode D1, freewheeling diode D2, and a first coil and a second coil. The first coil has a head end connected to the power supply VCC, and a tail end connected to the output channel of the control circuit. The bypass capacitor group consisting of capacitor C3, capacitor C4 and capacitor C5 is connected in parallel at both ends of the power supply; the freewheeling diode D1 is connected in anti-parallel at both ends of the first coil; the second coil has a head end connected to the power supply VCC, and a tail end connected to the output channel of the control circuit. The bypass capacitor group consisting of capacitor C6, capacitor C7 and capacitor C8 is connected in parallel at both ends of the power supply; and the freewheeling diode D2 is connected in anti-parallel at both ends of the second coil.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The product of the present invention has a long service life.

[0018] The present invention utilizes the instantaneous solidification property of magnetorheological fluid after magnetization to wrap the brake disc and apply braking force, which will greatly reduce the degree of wear on the workpiece and extend the service life of the product.

[0019] 2. The product of the present invention has great braking force.

[0020] The present invention provides two braking structures. One is a brake disc set in a sealed cavity. The brake disc is composed of multiple discs connected in sequence from large to small. The combination of multiple discs increases the braking surface of the magnetorheological fluid, thereby better contacting the magnetorheological fluid and strengthening the braking force after magnetic solidification. The other is a pressure-enhancing bump on the conveyor belt controlled by a motor. The pressure-enhancing bump moves with the conveyor belt and is pressed onto the first pressure rod in turn. After the first pressure rod is subjected to downward pressure, it pushes the pressure disc to wrap around the brake disc. The downward pressure causes the multi-stage brake disc to stop rotating faster, thereby increasing the braking force, making it more suitable for new energy vehicles.

[0021] 3. The present invention has the ability to adjust the braking size.

[0022] The present invention adjusts the coil current through an external controller and a control circuit, thereby adjusting the solidification degree of the magnetorheological fluid and achieving the adjustment of the braking force.

[0023] 4. The present invention can increase pressure step by step.

[0024] The present invention provides a plurality of first pressurizing rods, and the pressurizing protrusions pressurize the first pressurizing rods in sequence through a conveyor belt, thereby realizing step-by-step pressurization control.

[0025] 5. The magnetorheological fluid of the present invention is stable during solidification.

[0026] Conventional MR fluid brakes typically feature only one electromagnetic coil, which gradually weakens during magnetic conduction, leading to unstable MR fluid solidification. The present invention incorporates an electromagnetic coil on the outer ring of the MR fluid and on the axle, strengthening the magnetic field and stabilizing the MR fluid's solidification.

[0027] 6. The present invention can keep the performance of magnetorheological fluid unchanged for a long time.

[0028] Because the performance of magnetorheological fluid will begin to decline when the temperature exceeds 90 degrees Celsius, the present invention designs a heat dissipation pipe and a connecting pipe, fills the pipe with coolant, and circulates the coolant through the two ports of the heat dissipation pipe, ensuring that the temperature of the magnetorheological fluid will not be too high and the performance of the magnetorheological fluid will be maintained unchanged for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1This is a schematic diagram of the appearance and structure of a magnetorheological fluid step-by-step braking device of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the heat dissipation pipe of the present invention;

[0031] Figure 3 This is a schematic diagram of the internal side structure of a magnetorheological fluid step-by-step braking device of the present invention;

[0032] Figure 4 This is a schematic diagram of the internal front structure of a magnetorheological fluid step-by-step braking device of the present invention;

[0033] Figure 5 for Figure 4 A magnified view of part A in FIG;

[0034] Figure 6 This is a three-dimensional diagram of the internal structure of a magnetorheological fluid step-by-step braking device of the present invention;

[0035] Figure 7 This is a control principle diagram of the coil current control module of the present invention;

[0036] Figure 8 This is a first coil output circuit diagram of the present invention;

[0037] Figure 9 This is a circuit diagram of the second coil output of the present invention;

[0038] Figure 10 This is a control circuit diagram of the present invention.

[0039] Reference numerals:

[0040] 1- axle, 2- bottom plate, 3- side plate, 4- bearing, 5- arc-shaped magnetic isolation plate, 6- first coil, 7- sealed chamber, 701- arc-shaped magnetic conductive plate, 702- rectangular magnetic isolation sealing plate, 703- circular magnetic isolation sealing plate, 8- magnetic isolation ring, 9- second coil, 10- brake disc, 1001- disc, 1002- flange, 11- first connecting rod, 12- fixed plate, 13- motor, 14- conveyor belt, 15- driving wheel, 16- driven wheel, 17- second connecting rod, 18- Pressure bump, 19-upper half-ring pressure plate, 20-lower half-ring pressure plate, 21-groove, 22-pressure rod, 2201-first pressure rod, 2202-second pressure rod, 2203-annular limit block, 23-reset spring, 24-connecting pipe, 25-inner cavity, 26-telescopic rod, 27-limit spring, 28-positioning rod, 29-heat dissipation pipe, 30-external controller, 31-control circuit; a-rear, b-front, c-left, d-right, e-upper, f-lower. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited to the scope of the examples.

[0042] Example 1:

[0043] like Figure 1-6 As shown, a magnetorheological fluid step-by-step braking device includes a housing and an axle 1. The housing is surrounded by front and rear bottom plates 2 and side plates 3 to form a cylindrical working chamber. The axle 1 passes through the front and rear bottom plates 2 and is arranged in the working chamber. The axle 1 is connected to the front and rear bottom plates 2 respectively through bearings 4. A magnetorheological braking unit is provided in the working chamber. The magnetorheological braking unit includes an arc-shaped magnetic isolation plate 5, a first coil 6, a sealed chamber 7, a magnetic isolation ring 8, a second coil 9 and a brake disc 10. The arc-shaped magnetic isolation plate 5 has two sections, which are symmetrically arranged on the inner side of the side plate 3. The magnetic field is isolated to concentrate the magnetic force and prevent the magnetization of the device parts. A first gap is provided between the upper and lower ends of the two arc-shaped magnetic isolation plates 5. The first coil 6 has two sections, which are symmetrically arranged on the inner side of the arc-shaped magnetic isolation plate 5. A second gap is provided between the upper and lower ends of the two sections of the first coil 6. The sealed cavity 7 is provided in the cavity surrounded by the two sections of the first coil 6. The sealed cavity 7 is a cavity for containing magnetorheological fluid surrounded by the arc-shaped magnetic conductive plate 701, the rectangular magnetic isolation sealing plate 702 and the circular magnetic isolation sealing plate 703. , the arc-shaped magnetic conductive plate 701 has two sections, which are symmetrically arranged on the inner side of the first coil 6, and are used to evenly diffuse the magnetic field of the first coil 6, so that the magnetorheological fluid in the sealed cavity 7 is evenly magnetized. A third interval is provided between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates 701; there are two rectangular magnetic isolation sealing plates 702, which are respectively arranged between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates 701, and the third interval is sealed to isolate the magnetic field to avoid affecting the motor 13; the circular magnetic isolation sealing plates 703 have two pieces, respectively The front and rear ends of the two arc-shaped magnetic conductive plates 701 are used to isolate the magnetic field to avoid affecting the outside world. The front and rear circular magnetic isolation sealing plates 703 are fixedly connected to the base plate 2 at the corresponding position through the first connecting rod 11; the magnetic isolation ring 8, the second coil 9 and the brake disc 10 are arranged in the sealed cavity 7, the second coil 9 is sleeved on the axle 1, the brake disc 10 is sleeved on the second coil 9, the magnetic isolation ring 8 is sleeved on the axle 1 and is respectively located between the second coil 9 and the front and rear bearings 4, which are used to isolate the magnetic field and concentrate the magnetic field in the sealed cavity 7.

[0044] The brake disc 10 is composed of a plurality of discs 1001 connected in sequence from large to small, and a flange 1002 is provided on the outer edge of each disc 1001 .

[0045] A group of transmission pressure mechanisms and a fixed plate 12 are provided at each first interval. The transmission pressure mechanism is provided on the outside of the fixed plate 12. The fixed plate 12 is located on the outside of the rectangular magnetic isolation sealing plate 702 and is fixedly connected to the two arc-shaped magnetic isolation plates 5. The fixed plate 12 is fixedly connected to the left and right arc-shaped magnetic isolation plates 5; the transmission pressure mechanism includes a motor 13, a conveyor belt 14, a driving wheel 15 and a plurality of driven components. The driving wheel 15 and the plurality of driven components are arranged horizontally front and back. The driving wheel 15 is provided on the power output shaft of the motor 13, and the motor 13 is fixedly connected to any arc-shaped magnetic isolation plate 5; each group of driven components includes a driven wheel and a second connecting rod. The driven wheel 16 is provided on the second connecting rod 17. The second connecting rod 17 is fixedly connected to any arc-shaped magnetic isolation plate 5. The conveyor belt 14 is installed on the driving wheel 15 and the driven wheel 16 for rotation and transmission. The plurality of driven wheels 16 are used to firmly pressurize the pressure protrusions. A section of the transmission surface of the conveyor belt 14 is provided with a pressure protrusion 18.

[0046] An upper semi-ring pressure plate 19 matching its curvature is provided directly above each disc 1001, and a lower semi-ring pressure plate 20 matching its curvature is provided directly below. Both the upper semi-ring pressure plate 19 and the lower semi-ring pressure plate 20 are located in the sealed cavity, and the inner edges of the upper semi-ring pressure plate 19 and the lower semi-ring pressure plate 20 are provided with a groove 21 for embedding the flange 1002. In the non-pressurized state, the upper semi-ring pressure plate 19 and the lower semi-ring pressure plate 20 maintain the same first downward pressure distance L1 with the corresponding disc 1001. After pressurization, the disc 1001 is embedded in the annular structure formed by the combination of the corresponding upper semi-ring pressure plate 19 and the lower semi-ring pressure plate 20; the top of the upper semi-ring pressure plate 19 and the bottom of the lower semi-ring pressure plate 20 are respectively fixedly connected to the pressure assembly, which includes a pressure rod and a return spring 23. The pressure rod 22 consists of a first pressure rod 2201 with a larger diameter and a second pressure rod 220 with a smaller diameter. The pressure rod 2202 is connected up and down. The first pressure rod 2201 is located between the conveyor belt 14 and the fixed plate 12 and can be moved up and down to be clamped on the fixed plate 12. The top of the first pressure rod 2201 is set to a slope structure in the front and back directions. In the pressurized state, the pressure protrusion 18 of the conveyor belt 14 is pressed on the slope structure of the first pressure rod 2201; the second pressure rod 2202 passes through the rectangular magnetic isolation sealing plate 702 and is connected to the corresponding upper half-ring pressure disk 19 or the lower half-ring pressure disk 20. The reset spring 23 is located between the fixed plate 12 and the rectangular magnetic isolation sealing plate 702 and is installed on the second pressure rod 2202. The lower part of the reset spring 23 is fixedly connected to the rectangular magnetic isolation sealing plate 702; the second pressure rod 2202 is also provided with a circle of annular limit blocks 2203. When not in the pressurized state, the annular limit blocks 2203 abut against the inner side of the rectangular magnetic isolation sealing plate 702. The distance that the pressure projection 18 pushes the first pressure rod 2201 downward is not greater than the first downward pressure distance L1. If it is greater than the first downward pressure distance L1, excessive wear will occur on the upper half-ring pressure plate 19, the lower half-ring pressure plate 20, and the brake disc 10. Only when the pressure projection 18 pushes the first pressure rod 2201 downward by a distance not greater than the first downward pressure distance L1 can the upper half-ring pressure plate 19 and the lower half-ring pressure plate 20 generate downward pressure on the brake disc 10 without excessive wear. The diameter of the first pressure rod 2201 is greater than the diameter of the return spring 23, so that it can be reset by the return spring 23 after completing the downward pressure.The first pressure rod 2201 is movably attached to the fixed plate 12 via an elastic snap-fit ​​assembly. The fixed plate 12 has an inner cavity 25. The elastic snap-fit ​​assembly is located in the inner cavity 25 on the left and right sides of the first pressure rod 2201. The elastic snap-fit ​​assembly is horizontally connected in sequence by a telescopic rod 26, a limit spring 27, and a positioning rod 28. One end of the telescopic rod 26 extends from the inner cavity 25. The first pressure rod 2201 overlaps the extended ends of the two telescopic rods 26. The overlapping surfaces are configured as mutually matching inclined surfaces. This facilitates pushing the telescopic rods 26 apart when the first pressure rod 2201 is pressed downward, and the telescopic rods 26 can better support the first pressure rod 2201. The positioning rod 28 is fixedly connected to the wall of the inner cavity 25. A curved heat dissipation pipe 29 is provided between each of the front and rear base plates 2 and the corresponding circular magnetic isolation sealing plate 703. One end of the heat dissipation pipe 29 is located on the housing side plate 3, and the other end of the pipe is connected by a connecting pipe 24.

[0047] Example 2:

[0048] like Figure 6 As shown, based on Example 1, the first coil 6 and the second coil 9 of the present invention are both controlled by a coil current control module, which includes an external controller 30, a control circuit 31 and an output circuit including the first coil 6 and the second coil 9. The external controller 30 is electrically connected to the input end of the control circuit 31, and the output end of the control circuit 31 is electrically connected to the output circuit; the external controller 30 adopts a PLC or a microcontroller.

[0049] The external controller 30 can be controlled by various PLCs, microcontrollers or other controllers. The present invention takes the mature Arduino development board as the controller control channel 1 for output as an example; the development board digital signal output port 9 is used as the output port of the PWM control signal, and is connected to the signal input port 1 ( Figure 10 Connect the digital signal port 10 of the development board to the enable terminal of the control circuit 31 ( Figure 10 The Arduino development board's analog signal port A0 is connected to the current sampling output port of the control circuit 31. The internal ADC reads the voltage across the sampling resistor to obtain current information.

[0050] Because the maximum operating current required by the magnetorheological brake is 3A, the control circuit 31 uses the STMicroelectronics power control chip L9349LF as its core component. Its maximum load current is 5A, fully meeting the control requirements of the magnetorheological brake. The chip operates at a voltage of 4.5 to 32V and has four independently controllable output channels. By controlling the duty cycle of the input PWM signal, the load current, and thus the brake, can be easily controlled.

[0051] Figure 10 U2 in the figure is a three-terminal voltage regulator that converts the power supply VCC to 5V to power the chip's logic circuits. VIN, VOUT (TAB), and ADJ (GND) are its power input, 5V output, and ground pins, respectively. Pin 3 (i.e., the VIN pin) is connected to the power supply VCC. VOUT (TAB) is connected to the chip's VS pin (PIN5) to power the chip's logic circuits. Capacitors C1 and C2 are filter capacitors for the chip's 5V logic power supply and are connected across VOUT (TAB) and ADJ (GND) of the three-terminal voltage regulator U2. The capacitances of capacitors C1 and C2 are 100uF and 0.1uF, respectively.

[0052] The chip's four outputs, OUT1 (5A), OUT2 (5A), OUT3 (3A), and OUT4 (3A), correspond to PIN2, PIN9, PIN12, and PIN19, respectively. Resistors R1, R2, R5, and R6 are connected directly in series with the output channels, serving as output current sampling resistors with a resistance of 0.1 ohms. The positive and negative current feedback signals for the channel (channel number) are connected to the ADC of an external controller 30 to sample the output current data, corresponding to a range of 100mV / 1A. The control signal inputs corresponding to the four outputs are IN1, IN2, IN3, and IN4, corresponding to pins PIN17, PIN14, PIN7, and PIN4. The external controller 30 receives PWM control signals via these input pins, controlling the output channel current by varying the PWM signal's duty cycle. A higher duty cycle results in a higher output current. Resistors R3, R4, R7, and R8 are 10 kilo-ohm pull-down resistors for the signal input. One end of the pull-down resistor is connected to the control signal input, and the other end is grounded. This prevents the chip from erroneously turning on when no signal input is present and encountering interference. EN (PIN16) is the chip enable terminal (active high), determining whether the chip is active. When the external controller 30 outputs a high level, the chip function is activated. Resistor R9 is a pull-down resistor for EN, connected between EN and GND. Its resistance is the same as the other four pull-down resistors, ensuring the chip does not erroneously turn on when no signal input is present. PIN1, PIN10, PIN11, PIN15, PIN20, and PIN21 are circuit grounds.

[0053] Table 1 is the pin function table of the chip and three-terminal regulator U2

[0054]

[0055]

[0056] like Figure 7 As shown, the first coil 6 is connected to the power supply VCC at its head end and to the circuit output channel at its tail end. A bypass capacitor bank consisting of three 10uF capacitors, C3, C4, and C5, is connected in parallel across the power supply to improve the brake's transient response. A freewheeling diode D1 is connected in antiparallel across the first coil 6 of the magnetorheological brake to prevent the induced electromotive force from rapidly switching from the braking to the non-braking state, potentially causing circuit breakdown and improving safety and stability. The current in the first coil 6 is regulated by an external controller 30.

[0057] like Figure 8 As shown, the leading end of the second coil 9 is connected to the power supply VCC, and the trailing end is connected to the circuit output channel. A bypass capacitor bank consisting of three 10uF capacitors, C6, C7, and C8, is connected in parallel across the power supply to enhance the brake's transient response. A freewheeling diode D2 is connected in antiparallel across the second coil 9 of the magnetorheological brake to prevent the induced electromotive force from rapidly switching from the braking to the non-braking state, potentially damaging the circuit and improving safety and stability. The current in the second coil 9 is regulated by an external controller 30.

[0058] When the car is driving normally, the motor 13, the first coil 6 and the second coil 9 are not energized, the magnetorheological fluid is in a liquid state, and the entire magnetorheological fluid step-by-step braking device rotates with the axle 1; when the car brakes, the first coil 6 and the second coil 9 are energized, causing the magnetorheological fluid to instantly turn into a solid state. After solidification, the magnetorheological fluid generates a braking force that prevents the brake disc 10 from rotating. The brake disc 10 is connected to the axle 1, thereby preventing the axle 1 from rotating, thereby achieving braking. The motor 13 can also be started at the same time, and the motor 13 drives the driving wheel 15 to rotate, and then the conveyor belt 14 rotates together with the transmission wheel, and the pressure protrusion 18 presses the first pressure rod 2201 step by step as the conveyor belt 14 rotates, and multiple transmission wheels firmly press the pressure protrusion 18 downward, and the first pressure rod 2201 breaks away from the telescopic rod 26 and presses down to push the second pressure rod 2202, the limit spring 27 is compressed, and the return spring 23 is compressed by the first pressure rod 2201, and the second pressure rod 2202 pushes the upper and lower semi-ring pressure plates 20 to pressurize the brake disc 10, realizing boost braking; after braking, the starting motor 13 moves the pressure protrusion 18 out of the first pressure rod 2201, the return spring 23 is restored, and the first pressure rod 2201 is pushed upward, and the first pressure rod 2201 is re-connected to the telescopic rod 26, the limit spring 27 is restored, and the upper and lower semi-ring pressure plates 20 leave the brake disc 10.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "front", "back", "left", "right", "up", "down", "head", "tail", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention. It should also be noted that, unless otherwise clearly specified and limited, terms such as "connected" and "connect" should be understood in a broad sense, for example, it can be a fixed connection; it can be a detachable connection; it can also be a point connection; it can be a direct connection; it can be an indirect connection through an intermediate medium, so that the internals of the two elements can be connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The device connection methods not fully described in the present invention are all understood according to the conventional connection methods in the field.

[0060] The above embodiments are only specific examples to further illustrate the purpose, technical solutions and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent replacements, improvements, etc. made within the scope of the present invention are included in the scope of protection of the present invention.

Claims

1. A magnetorheological fluid step-by-step brake device, comprising a housing and an axle, wherein the housing is surrounded by front and rear bottom plates and side plates to form a cylindrical working chamber, the axle passes through the front and rear bottom plates and is arranged in the working chamber, and the axle is connected to the front and rear bottom plates respectively through bearings, characterized in that: A magnetorheological brake unit is provided in the working chamber, and the magnetorheological brake unit includes an arc-shaped magnetic isolation plate, a first coil, a sealed chamber, a magnetic isolation ring, a second coil and a brake disc. The arc-shaped magnetic isolation plate has two sections, which are symmetrically arranged on the inner side of the side plate, and a first gap is provided between the upper and lower ends corresponding to the two sections of the arc-shaped magnetic isolation plate; the first coil has two sections, which are arc-shaped and symmetrically arranged on the inner side of the arc-shaped magnetic isolation plate, and a second gap is provided between the upper and lower ends corresponding to the two sections of the first coil; the sealed chamber is provided in a cavity surrounded by the two sections of the first coil, and the sealed chamber is a cavity for containing magnetorheological fluid surrounded by an arc-shaped magnetic conductive plate, a rectangular magnetic isolation sealing plate and a circular magnetic isolation sealing plate, and the arc-shaped magnetic conductive plate There are two sections, which are symmetrically arranged on the inner side of the first coil, and a third interval is provided between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates; there are two rectangular magnetic isolation sealing plates, which are respectively arranged between the upper and lower ends corresponding to the two arc-shaped magnetic conductive plates to seal the third interval; there are two circular magnetic isolation sealing plates, which are respectively arranged at the front and rear ends of the two arc-shaped magnetic conductive plates, and the front and rear circular magnetic isolation sealing plates are respectively fixedly connected to the bottom plates at corresponding positions through the first connecting rod; the magnetic isolation ring, the second coil and the brake disc are arranged in a sealed cavity, the second coil is sleeved on the axle, the brake disc is sleeved on the second coil, and the magnetic isolation ring is sleeved on the axle and is respectively located between the second coil and the front and rear bearings; The brake disc is composed of a plurality of discs connected in sequence from large to small, and a flange is provided on the outer edge of each disc; A group of transmission pressure mechanisms and a fixed plate are provided at each of the first intervals, the transmission pressure mechanism is provided on the outside of the fixed plate, and the fixed plate is fixedly connected to the left and right arc-shaped magnetic isolation plates; the transmission pressure mechanism comprises a motor, a conveyor belt, a driving wheel and a plurality of driven components, the driving wheel and the plurality of driven components are arranged horizontally front and back, the driving wheel is provided on the power output shaft of the motor, and the motor is fixedly connected to any arc-shaped magnetic isolation plate; each group of the driven components comprises a driven wheel and a second connecting rod, the driven wheel is provided on the second connecting rod, the second connecting rod is fixedly connected to any arc-shaped magnetic isolation plate, the conveyor belt is installed on the driving wheel and the driven wheel for rotation and transmission, and a pressure protrusion is provided on a section of the transmission surface of the conveyor belt; Each of the discs is provided with an upper semi-ring pressure disc that matches its curvature directly above, and a lower semi-ring pressure disc that matches its curvature directly below, and the upper semi-ring pressure disc and the lower semi-ring pressure disc are both located in the sealed cavity, and the inner edges of the upper semi-ring pressure disc and the lower semi-ring pressure disc are provided with grooves for embedding flanges. In the non-pressurized state, the upper semi-ring pressure disc and the lower semi-ring pressure disc maintain the same first downward pressure distance with the corresponding disc, and after pressurization, the disc is embedded in the annular structure formed by the combination of the corresponding upper semi-ring pressure disc and the lower semi-ring pressure disc; the top of the upper semi-ring pressure disc and the bottom of the lower semi-ring pressure disc are respectively fixedly connected to the pressure assembly, and the pressure assembly includes a pressure rod and a return spring, and the pressure rod is connected by a first pressure rod with a larger diameter and a second pressure rod with a smaller diameter, and the first pressure rod is positioned The first pressure rod is clamped on the fixed plate between the conveyor belt and the fixed plate and can move up and down. The top of the first pressure rod is set to an inclined structure in the front-to-back direction. In the pressurized state, the pressure protrusion of the conveyor belt is pressed on the inclined structure of the first pressure rod; the second pressure rod passes through the rectangular magnetic isolation sealing plate and is connected with the corresponding upper half ring pressure disk or lower half ring pressure disk. The reset spring is located between the fixed plate and the rectangular magnetic isolation sealing plate and is installed on the second pressure rod, and the lower part of the reset spring is fixedly connected to the rectangular magnetic isolation sealing plate; the second pressure rod is also provided with a circle of annular limit blocks. When not in the pressurized state, the annular limit blocks abut against the inner side of the rectangular magnetic isolation sealing plate, and the pressure protrusion pushes the first pressure rod downward by a distance not greater than the first downward distance; the diameter of the first pressure rod is greater than the diameter of the reset spring; The first pressure rod is movably clamped to the fixed plate by an elastic clamping assembly, and the fixed plate is provided with an inner cavity. The elastic clamping assembly is respectively arranged in the inner cavities on the left and right sides of the first pressure rod. The elastic clamping assembly is horizontally connected in sequence by a telescopic rod, a limit spring and a positioning rod. One end of the telescopic rod extends out of the inner cavity. The first pressure rod is overlapped on the extended ends of the two telescopic rods, and the overlapping surfaces are set as mutually matching inclined structures. The positioning rod is fixedly connected to the inner cavity wall.

2. A magnetorheological fluid step-by-step braking device according to claim 1, characterized in that: A curved heat dissipation pipe is provided between the front and rear bottom plates and the circular magnetic isolation sealing plates in corresponding positions. One end of the heat dissipation pipe is provided on the side plate of the shell, and the other end of the pipe is connected by a connecting pipe.

3. The magnetorheological fluid step-by-step braking device according to claim 1, characterized in that: The first coil and the second coil are both controlled by a coil current control module, which includes an external controller, a control circuit and an output circuit including the first coil and the second coil. The external controller is electrically connected to the input end of the control circuit, and the output end of the control circuit is electrically connected to the output circuit. The external controller adopts a PLC or a microcontroller.

4. A magnetorheological fluid step-by-step braking device according to claim 3, characterized in that: The control circuit includes a power supply VCC, a three-terminal voltage regulator U2, a capacitor C1, a capacitor C2, a chip, and resistors R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10. The three-terminal voltage regulator U2 adopts AMS1117-5v, and the chip adopts L9349LF. Pin 3 of the three-terminal voltage regulator U2 is connected to the power supply VCC, and pin 2 of the three-terminal voltage regulator U2 is connected to the VS pin of the chip. The capacitor C1 and the capacitor C2 are connected between pin 2 and pin 1 of the three-terminal voltage regulator U2; the 4 outputs OUT1, OUT2, OUT3, and OUT4 of the chip correspond to PIN2, PIN9, PIN12, and PIN19 respectively, and the resistors R1, R2, R5, and R6 are directly connected in series with the output channel for output current sampling, and the channel current positive feedback and channel current negative feedback drawn from both ends are connected to the ADC of the external controller to sample the output current data; The control signal inputs corresponding to the 4 outputs are IN1, IN2, IN3, and IN4, and the corresponding pins are PIN17, PIN14, PIN7, and PIN4; the external controller inputs the PWM control signal by connecting to the input pins; resistors R3, R4, R7, and R8 are pull-down resistors at the signal input end, and one end of the pull-down resistor is connected to the control signal input end and the other end is grounded; the EN end, i.e., PIN16, is the enable end of the chip, i.e., a high level is valid. When the external controller outputs a high level, the chip function is activated. Resistor R9 is a pull-down resistor at the EN end, connected between EN and GND, and its resistance value is the same as that of the four pull-down resistors of resistors R3, R4, R7, and R8; PIN1, PIN10, PIN11, PIN15, PIN20, and PIN21 are circuit grounds.

5. A magnetorheological fluid step-by-step braking device according to claim 4, characterized in that: The output circuit includes capacitor C3, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, freewheeling diode D1, freewheeling diode D2, a first coil and a second coil. The first coil has a head end connected to a power supply VCC, and a tail end connected to an output channel of a control circuit. A bypass capacitor group consisting of capacitors C3, C4 and C5 is connected in parallel at both ends of the power supply; a freewheeling diode D1 is connected in reverse parallel at both ends of the first coil; the second coil has a head end connected to a power supply VCC, and a tail end connected to an output channel of a control circuit. A bypass capacitor group consisting of capacitors C6, C7 and C8 is connected in parallel at both ends of the power supply; and a freewheeling diode D2 is connected in reverse parallel at both ends of the second coil.

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