Brake-by-wire device based on angle module, brake system and brake method

Abstract

The invention discloses a brake-by-wire device based on an angle module, a brake system and a brake method, and belongs to the technical field of vehicle engineering. The brake-by-wire device comprises a brake disc, a plurality of guide fixing rods, a friction assembly, a lead screw nut and a lead screw motor; the brake disc is fixed on the inner side of the hub bearing shell and rotates along with a wheel; the friction assembly is arranged between the brake disc and the steering knuckle; one end of the guide fixing rod is fixed with the hub bearing stator, and the other end of the guide fixing rod is fixed with the steering knuckle; the lead screw nut is fixed to the inner side of the friction assembly. The lead screw motor is fixed to the inner side of the steering knuckle, and the lead screw is in threaded connection with the lead screw nut. A lead screw of the lead screw motor rotates, and then a lead screw nut drives the friction assembly to move along the guide fixing rod. When the friction assembly moves to abut against the inner side face of the brake disc, the brake disc is braked, and when the friction assembly is separated from the inner side face of the brake disc, the brake disc can rotate along with wheels. The invention has the advantages of high space utilization rate, quick braking response, long service life and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle engineering, and relates to a vehicle braking structure, and in particular to a brake-by-wire device, a braking system and a braking method based on an angle module. Background Art

[0002] Traditional vehicle braking systems generally use mechanical friction braking, and their technical paths are mainly divided into two typical structures: hydraulic drive and electromechanical drive. In the hydraulic braking system, the hydraulic cylinder generates axial thrust to drive the piston caliper to clamp the brake disc; while the electromechanical braking system uses an electric motor drive to replace the hydraulic actuator, and converts the motor torque into the caliper clamping force through the reduction mechanism. Despite the differences in driving methods, both types of braking systems require the arrangement of brake actuator components including piston calipers and drive mechanisms on the radial periphery of the brake disc.

[0003] With the rapid development of in-wheel motor technology, the spatial layout of the braking system faces new challenges. Since the stator assembly of the in-wheel motor needs to occupy the core space inside the wheel hub, the traditional caliper brake arranged along the periphery of the brake disc has inherent defects such as excessive axial size and insufficient radial envelope space, which makes it difficult to effectively integrate into the limited structural space of the in-wheel motor. Especially in four-wheel independent steering vehicles, the wheels need to achieve large-angle steering deflection (usually more than ±90°), and the traditional external caliper structure is very easy to interfere with the surrounding components such as suspension components and wheel arch linings during steering, which seriously restricts the freedom of design of the steering system and the optimization of the vehicle space layout.

[0004] At present, the improvement solutions for this technical bottleneck in the industry are mostly focused on the local optimization of the caliper structure. However, due to the inherent structure of traditional brakes, they have not fundamentally solved the core problem of the excessive space occupancy of the brake unit and the coexistence of dynamic interference risks. Summary of the invention

[0005] The present invention provides a brake-by-wire device, a braking system and a braking method based on an angle module to overcome the defects of the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a brake-by-wire device based on an angle module, which is used for wheel braking. The wheel hub motor drives the wheel to rotate through the wheel hub bearing rotor; the kingpin steering gear drives the wheel to steer through the steering knuckle. The brake-by-wire device includes a brake disc, a plurality of guide fixing rods, a friction assembly, a screw nut and a screw motor; the brake disc is fixed to the inner side of the wheel hub bearing housing and rotates with the wheel; the friction assembly is arranged between the brake disc and the steering knuckle; the guide fixing rod passes through the friction assembly, one end is fixed to the wheel hub bearing stator, and the other end is fixed to the steering knuckle; the screw nut is fixed to the inner side of the friction assembly; the screw motor is fixed to the inner side of the steering knuckle, and the screw is threadedly connected to the screw nut; the screw of the screw motor rotates, and the screw nut drives the friction assembly to move along the guide fixing rod; when the friction assembly moves to abut against the inner side of the brake disc, the brake disc is braked, and when the friction assembly is detached from the inner side of the brake disc, the brake disc can rotate with the wheel.

[0007] In the present invention, the inner side and the outer side refer to the direction toward the center of the vehicle as the inner side and the direction away from the center of the vehicle as the outer side based on the entire vehicle.

[0008] Furthermore, the friction assembly includes a friction disc and a plurality of friction plates; the plurality of friction plates are fixed on the outer side of the friction disc; the screw nut is fixed on the inner side of the friction disc; the plurality of friction plates move synchronously with the screw nut through the friction disc; when the plurality of friction plates move to abut against the inner side of the brake disc, the brake disc is braked, and when the plurality of friction plates detach from the inner side of the brake disc, the brake disc can rotate with the wheel.

[0009] Furthermore, it also includes a rotary transformer; the rotary transformer is fixed on the inner side of the hub bearing stator to detect the position of the hub bearing rotor, thereby obtaining the rotation speed of the wheel.

[0010] Furthermore, the brake disc is annular and is sleeved around the wheel hub bearing stator; the friction disc is annular and is sleeved around the rotary transformer; a flange is fixed circumferentially to the lead screw nut, which is fixed to the inner side of the friction disc through the flange, and the guide fixing rod passes through the flange; the lead screw nut passes inwardly through the center of the steering knuckle; the lead screw motor is equipped with a lead screw motor support frame, which is fixed to the center of the inner side of the steering knuckle through the lead screw motor support frame and is located on the inner side of the lead screw nut.

[0011] Furthermore, a ball is provided between the screw nut and the thread of the screw.

[0012] Furthermore, the screw motor is an electromagnetic brake motor. When the screw motor is powered off, the screw is firmly locked by electromagnetic braking to prevent the screw motor from sliding down naturally due to the workload or moving horizontally due to external force, and keep the work stopped in place; after power is turned on, the screw is released in time without affecting the normal operation of the screw motor.

[0013] In a second aspect, the present invention also provides a vehicle braking system, including a hub motor braking unit, the hub motor braking unit includes a hub motor, the hub motor is connected to the battery of the vehicle, and can achieve regenerative braking, recovering energy while braking, and the recovered energy can charge the battery; the braking system also includes the above-mentioned wire-controlled braking device based on the angle module; the wire-controlled braking device achieves mechanical friction braking by moving the friction component.

[0014] Furthermore, the hub motor braking unit also includes a capacitor and an energy release component; the hub motor is connected to the capacitor, and the energy recovered by the motor braking can charge the capacitor; the capacitor charges the energy release component, and the energy release component releases energy.

[0015] Furthermore, the energy release component includes the vehicle's PTC, water tank, water pump, pipeline and fan; the water tank and the water pump are connected by pipelines to form a cooling circuit, and the coolant circulates in the cooling circuit through the water pump; the PTC heats the coolant in the pipeline; the fan dissipates heat from the coolant in the water tank; the capacitor supplies power to the water pump, PTC and fan.

[0016] In a third aspect, the present invention also provides a braking method for the above-mentioned vehicle braking system: when the speed of the wheel is in the constant torque zone of the hub motor, mechanical friction braking is performed through the wire control braking device; when the speed of the wheel is in the constant power zone of the hub motor: if the SOC is lower than the braking energy recovery limit, the energy recovered by the motor braking is used to charge the vehicle's battery; if the SOC is higher than the braking energy recovery limit, the energy recovered by the motor braking is used to charge the capacitor, and at the same time, the water pump drives the coolant to circulate in the cooling circuit, the PTC heats the coolant in the pipeline, and the fan dissipates heat from the coolant in the water tank; if the SOC is higher than the braking energy recovery limit and the capacitor reaches its rated capacitance, mechanical friction braking is performed through the wire control braking device.

[0017] The beneficial effects of the present invention are as follows: the present invention provides a brake-by-wire device based on an angle module, which realizes the arrangement of a brake-by-wire system in the limited space of the angle module, effectively improves the space utilization of the angle module, and shortens the braking response time compared to hydraulic drive. Specifically, the present invention arranges the driving part of the brake-by-wire device in the center of the brake disc, and arranges the friction plate and the friction disc at the edge of the brake disc to generate a braking force by friction, so that the brake-by-wire device can be installed inside the wheel hub motor, thereby improving the space utilization of the wheel.

[0018] The present invention also provides a braking system that has both driving braking and parking braking functions. The braking function is performed by a braking method, which can reduce unnecessary wear of the friction plate, extend the service life of the friction plate, and reduce the energy loss of the vehicle. Specifically, during the braking process, the energy recovered by the wheel hub motor braking is used for coolant circulation, PTC heating of the coolant, and heat dissipation of the coolant, thereby increasing the proportion of the motor braking function of the wheel hub motor, thereby avoiding the problem of thermal decay of the friction disc and ultimately causing brake failure due to long-term mechanical friction braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the structure of a brake-by-wire device based on an angle module; Figure 2 It is a structural exploded diagram of a brake-by-wire device based on an angle module (excluding the guide fixing rod); Figure 3 It is a cross-sectional view of a brake-by-wire device based on a corner module; Figure 4 It is a schematic diagram of the structure of some wheel hub motor brake units; The marks in the accompanying drawings are: 11, wheel hub bearing rotor; 12, rim connecting bolt; 13, wheel hub bearing housing; 14, wheel hub bearing stator; 2, steering knuckle; 3, brake disc; 4, guide fixing rod; 5, friction assembly; 51, friction disc; 52, friction plate; 6, screw nut; 61, flange; 7, screw motor; 71, screw motor support frame; 8, rotating transformer; 91, capacitor; 92, PTC; 93, water tank; 94, water pump; 95, pipeline; 96, fan. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0021] like Figure 1~Figure 3 As shown, this embodiment provides a brake-by-wire device based on an angle module for wheel braking, which is arranged on the wheel hub bearing and the steering knuckle 2 of the wheel.

[0022] The hub motor drives the wheel to rotate through the hub bearing rotor 11. Specifically, a plurality of rim connecting bolts 12 are fixed on the hub bearing rotor 11, and the rim connecting bolts 12 pass through the hub bearing housing 13 to connect the hub motor rotor to the rim of the wheel. The wheel, the hub motor hub bearing and the connection method are all prior art and will not be described in detail. The kingpin steering gear drives the wheel to steer through the steering knuckle 2. Specifically, the kingpin steering gear housing is connected to the suspension, and the output shaft is fixed to the steering knuckle 2. The output shaft drives the steering knuckle 2 to rotate and then drives the angle module to achieve steering. The lower end of the steering knuckle 2 is connected to the suspension through a ball head.

[0023] like Figure 1~Figure 3As shown, the brake-by-wire device includes a brake disc 3 , a plurality of guide and fixing rods 4 , a friction assembly 5 , a screw nut 6 and a screw motor 7 .

[0024] The brake disc 3 is fixed to the inner side of the wheel hub bearing housing 13 and rotates with the wheel. The friction assembly 5 is arranged between the brake disc 3 and the steering knuckle 2. The guide fixing rod 4 passes through the friction assembly 5, one end of which is fixed to the wheel hub bearing stator 14 that does not rotate with the wheel, and the other end is fixed to the steering knuckle 2. That is, the guide fixing rod 4 fixes the steering knuckle 2 to the wheel hub bearing stator 14, transmits the wheel force to the steering knuckle 2, and then transmits it to the suspension through the kingpin steering gear housing and the ball head. The friction assembly 5 can move along the guide fixing rod 4.

[0025] The screw nut 6 is fixed on the inner side of the friction assembly 5. The screw motor 7 is fixed on the inner side of the steering knuckle 2, and the screw is threadedly connected to the screw nut 6. When the screw of the screw motor 7 rotates, the screw nut 6 drives the friction assembly 5 to move along the guide fixing rod 4. When the friction assembly 5 moves to abut against the inner side of the brake disc 3, the brake disc 3 is braked; when the friction assembly 5 is separated from the inner side of the brake disc 3, the brake disc 3 can rotate with the wheel.

[0026] Specifically, the friction assembly 5 includes a friction disc 51 and a plurality of friction plates 52. The plurality of friction plates 52 are fixed to the outer side of the friction disc 51. The screw nut 6 is fixed to the inner side of the friction disc 51. The plurality of friction plates 52 move synchronously with the screw nut 6 through the friction disc 51. When the plurality of friction plates 52 move to abut against the inner side of the brake disc 3, the brake disc 3 is braked; when the plurality of friction plates 52 are separated from the inner side of the brake disc 3, the brake disc 3 can rotate with the wheel.

[0027] The brake disc 3 is annular and is sleeved around the hub bearing stator 14. The friction disc 51 is annular and is sleeved around the rotary transformer 8. Figure 2 As shown, a flange 61 is fixed to the circumference of the screw nut 6, which is fixed to the inner side of the friction plate 51 through the flange 61, and the guide fixing rod 4 passes through the flange 61. The relative position of the friction plate 51 and the screw nut 6 is ensured to remain unchanged by the flange 61, and the axial movement is achieved on the guide fixing rod 4. The screw nut 6 passes through the center of the steering knuckle 2 inwardly. The screw motor 7 is equipped with a screw motor support frame 71, which is fixed to the center of the inner side of the steering knuckle 2 through the screw motor support frame 71 and is located on the inner side of the screw nut 6.

[0028] Preferably, a ball is provided between the thread of the screw nut 6 and the screw rod, and the ball reduces the friction between the screw nut 6 and the screw rod, making the axial movement of the screw nut 6 smoother.

[0029] The brake-by-wire device also includes a rotary transformer 8. The rotary transformer 8 is fixed to the inner side of the hub bearing stator 14, and detects the position of the hub bearing rotor 11, thereby obtaining the rotation speed of the wheel. The friction disc 51 is provided with a rotary transformer harness hole, and the harness of the rotary transformer 8 passes through the rotary transformer harness hole on the friction disc 51 and is connected to the MCU (hub motor control unit).

[0030] The screw motor 7 is an electromagnetic brake motor. When the screw motor 7 is powered off, the screw is firmly locked by electromagnetic braking to prevent the screw motor 7 from sliding down naturally due to the working load or moving horizontally due to external force when the power is off, and keep the working stop position state. After the power is turned on, the screw is released in time without affecting the normal operation of the screw motor 7.

[0031] When the VCU (vehicle control unit) issues a braking command, the screw motor 7 drives the screw to rotate, and the screw nut 6 converts the rotational motion of the screw into axial linear motion of the screw nut 6, thereby driving the friction disc 51 to move axially. When the friction plate 52 on the friction disc 51 contacts the brake disc 3 and is axially squeezed under the drive of the screw motor 7, a braking effect is achieved.

[0032] This embodiment also provides a vehicle braking system, including the above-mentioned wire control brake device and a hub motor brake unit. The wire control brake device realizes mechanical friction braking by moving the friction component 5. The hub motor brake unit includes a hub motor. The hub motor is connected to the battery of the vehicle and can realize regenerative braking, that is, energy is generated while braking, and the energy is recovered, and the recovered energy can charge the battery of the vehicle. The regenerative braking of the hub motor is a prior art and will not be described in detail.

[0033] like Figure 4 As shown, the wheel hub motor brake unit also includes a capacitor 91 fixed on the suspension and an energy release component. The wheel hub motor is connected to the capacitor 91, and the energy recovered by the motor braking can charge the capacitor 91. The capacitor 91 charges the energy release component, and the energy release component releases energy.

[0034] like Figure 4 As shown, specifically, the energy release component includes a vehicle PTC (positive temperature coefficient thermistor) 92, a water tank 93, a water pump 94, a pipe 95 and a fan 96. The water tank 93 and the water pump 94 are connected through the pipe 95 to form a cooling circuit, and the coolant circulates in the cooling circuit through the water pump 94. The PTC 92 heats the coolant in the pipe 95. The fan 96 dissipates the coolant in the water tank 93. The capacitor 91 supplies power to the water pump 94, the PTC 92 and the fan 96.

[0035] This embodiment also provides a braking method for the above vehicle braking system, which is specifically as follows: When the wheel speed is in the constant torque zone of the wheel hub motor, mechanical friction braking is performed through the wire control brake device. That is, when the vehicle speed is low, only mechanical friction braking is performed, and the VCU calculates the torque of the screw motor 7 and implements separate mechanical friction braking control for each wheel, thereby avoiding the problem of motor braking resulting in large braking torque due to the large torque of the motor external characteristic curve when the rotor speed is low, which in turn leads to poor comfort for passengers.

[0036] When the wheel speed is in the constant power range of the hub motor: If the SOC (battery state of charge) is lower than the braking energy recovery limit, the energy recovered by the motor braking is used to charge the vehicle's battery.

[0037] If the SOC is higher than the braking energy recovery limit, the energy recovered by the motor braking charges the capacitor 91, and at the same time, the water pump 94 drives the coolant to circulate in the cooling circuit, the PTC 92 heats the coolant in the pipeline 95, and the fan 96 dissipates the heat of the coolant in the water tank 93. That is, the energy recovered by the motor braking is released through the capacitor 91 and the energy release component to reduce the mechanical friction braking of the wire control brake device, and avoid the brake failure caused by the thermal decay of the friction disc 51 during long-term mechanical friction braking.

[0038] If the SOC is higher than the brake energy recovery limit and the capacitor 91 reaches its rated capacity, mechanical friction braking is performed through the wire control brake device. Under such working conditions, the brake disc 3 is prone to thermal decay, and reasonable braking distribution is required. Specifically: when the VCU does not receive a signal for a large-angle steering of the steering wheel, that is, by default, only braking is required on a large turning radius or a straight track, and the two diagonal wheels are controlled as a group. The VCU controls the two groups of wheels to perform mechanical friction braking alternately. When the brake disc 3 of one group of wheels thermally decays, the other group of wheels is controlled to brake; when the VCU receives a steering wheel angle signal, that is, when the vehicle brakes and turns, the VCU controls the two front wheels and the two rear wheels as a group, and controls the two groups of wheels to perform mechanical friction braking alternately. One group of wheels brakes and the other group of wheels turns. When the brake disc 3 of one group of wheels thermally decays, the group of wheels is controlled to turn and the other group of vehicles brakes.

[0039] When both the motor brake and the mechanical friction brake fail, the VCU achieves braking and steering redundancy by controlling the steering of the wheels.

[0040] When performing driving braking: When the VCU does not receive a signal for a large steering angle of the steering wheel, that is, by default, braking is only required on a large turning radius or a straight track, the VCU controls the front and rear wheels to turn inward at the same time. The greater the inward turning angle, the more obvious the braking effect. When the VCU receives a steering wheel angle signal, the VCU controls the front wheels to turn inward, and the rear wheels maintain the steering function to provide the required side force for the vehicle.

[0041] When parking brake is applied: VCU controls the front wheels to rotate outwards and the rear wheels to rotate inwards to achieve parking.

[0042] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0043] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0044] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A brake-by-wire device based on an angle module, used for wheel braking; a wheel hub motor drives the wheel to rotate via a wheel hub bearing rotor (11); a kingpin steering gear drives the wheel to steer via a steering knuckle (2); characterized in that: The wire-controlled brake device comprises a brake disc (3), a plurality of guide fixing rods (4), a friction assembly (5), a screw nut (6) and a screw motor (7); The brake disc (3) is fixed to the inner side of the wheel hub bearing housing (13) and rotates with the wheel; The friction component (5) is arranged between the brake disc (3) and the steering knuckle (2); The guide fixing rod (4) passes through the friction assembly (5), one end of which is fixed to the wheel hub bearing stator (14), and the other end of which is fixed to the steering knuckle (2); The screw nut (6) is fixed on the inner side of the friction assembly (5); The screw motor (7) is fixed on the inner side of the steering knuckle (2), and the screw is threadedly connected to the screw nut (6); The screw of the screw motor (7) rotates, and the screw nut (6) drives the friction component (5) to move along the guide fixing rod (4); when the friction component (5) moves to abut against the inner side of the brake disc (3), the brake disc (3) is braked, and when the friction component (5) is separated from the inner side of the brake disc (3), the brake disc (3) can rotate with the wheel.

2. The brake-by-wire device based on the corner module according to claim 1, characterized in that: The friction assembly (5) comprises a friction disc (51) and a plurality of friction plates (52); A plurality of friction plates (52) are fixed on the outer side surface of the friction plate (51); The screw nut (6) is fixed to the inner side of the friction plate (51); The plurality of friction plates (52) move synchronously with the screw nut (6) via the friction disc (51); when the plurality of friction plates (52) move to abut against the inner side surface of the brake disc (3), the brake disc (3) is braked; when the plurality of friction plates (52) are detached from the inner side surface of the brake disc (3), the brake disc (3) can rotate with the wheel.

3. The brake-by-wire device based on the corner module according to claim 2, characterized in that: Also includes a rotary transformer (8); The rotary transformer (8) is fixed on the inner side of the wheel hub bearing stator (14) to detect the position of the wheel hub bearing rotor (11).

4. The brake-by-wire device based on the corner module according to claim 3, characterized in that: The brake disc (3) is annular and is sleeved around the wheel hub bearing stator (14); The friction disk (51) is annular and is sleeved around the rotary transformer (8); A flange (61) is fixed to the circumference of the screw nut (6), and is fixed to the inner side surface of the friction plate (51) through the flange (61), and the guide fixing rod (4) passes through the flange (61); the screw nut (6) passes inward through the center of the steering knuckle (2); The screw motor (7) is equipped with a screw motor support frame (71), which is fixed at the center of the inner side of the steering knuckle (2) through the screw motor support frame (71) and is located on the inner side of the screw nut (6).

5. The brake-by-wire device based on the corner module according to claim 1, characterized in that: A ball is provided between the screw nut (6) and the thread of the screw.

6. The brake-by-wire device based on the corner module according to claim 1, characterized in that: The screw motor (7) is an electromagnetic brake motor.

7. A vehicle braking system, comprising a wheel hub motor braking unit, the wheel hub motor braking unit comprising a wheel hub motor, the wheel hub motor being connected to a vehicle battery, capable of achieving regenerative braking, recovering energy while braking, and the recovered energy being capable of charging the battery; characterized in that: The braking system also includes a brake-by-wire device based on an angle module as described in any one of claims 1 to 6; the brake-by-wire device achieves mechanical friction braking by moving a friction component (5).

8. The vehicle braking system according to claim 7, characterized in that: The hub motor brake unit also includes a capacitor (91) and an energy release component; The wheel hub motor is connected to the capacitor (91), and the energy recovered by the motor braking can charge the capacitor (91); The capacitor (91) charges the energy-releasing component, and the energy-releasing component releases energy.

9. The vehicle braking system according to claim 8, characterized in that: The energy release assembly includes a vehicle PTC (92), a water tank (93), a water pump (94), a pipeline (95), and a fan (96); The water tank (93) and the water pump (94) are connected via a pipeline (95) to form a cooling circuit, and the coolant circulates in the cooling circuit via the water pump (94); The PTC (92) heats the coolant in the pipeline (95); The fan (96) dissipates heat from the coolant in the water tank (93); The capacitor (91) supplies power to the water pump (94), the PTC (92) and the fan (96).

10. The braking method of a vehicle braking system according to claim 9, characterized in that: When the rotation speed of the wheel is in the constant torque zone of the wheel hub motor, mechanical friction braking is performed through the wire control brake device; When the wheel speed is in the constant power range of the hub motor: If the SOC is lower than the braking energy recovery limit, the energy recovered by the motor braking is used to charge the vehicle's battery; If the SOC is higher than the braking energy recovery limit, the energy recovered by the motor braking charges the capacitor (91), and at the same time the water pump (94) drives the coolant to circulate in the cooling circuit, the PTC (92) heats the coolant in the pipeline (95), and the fan (96) dissipates the heat of the coolant in the water tank (93); If the SOC is higher than the braking energy recovery limit and the capacitor (91) reaches its rated capacity, mechanical friction braking is performed through the wire control brake device.

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