A brake-by-wire apparatus for a small vehicle and a braking method thereof

Abstract

The small vehicle brake-by-wire device comprises a brake master cylinder, a brake master cylinder fixing support, a ball head top rod, a locking nut, a U-shaped push rod, a push rod motor fixing main support, a push rod motor fixing secondary support, a first pin shaft, a first split pin, a push rod motor, a second pin shaft, a second split pin, an automatic driving controller, a vehicle controller, a fuse, a five-pin relay and an eight-pin relay. The automatic driving controller sends a pressure building command to the vehicle controller according to the calculated braking demand, the vehicle controller controls the five-pin relay and the eight-pin relay to connect the forward power supply contact according to the received brake hydraulic pressure instruction, and the forward power supply is transmitted to the push rod motor. After receiving the forward power supply, the push rod motor rotates forward, pushes the U-shaped push rod and the ball head top rod forward, the front end of the ball head top rod contacts the inner wall of the brake master cylinder piston, and further pushes the brake master cylinder piston forward and backward, so that the corresponding hydraulic pressure is established in the brake pipeline, and the vehicle is slowed down or even stopped.

Description

TECHNICAL FIELD

[0001] The application relates to a small vehicle brake-by-wire device and a braking method thereof, and belongs to the field of automobile braking systems. BACKGROUND

[0002] With the rapid development of automatic driving technology, the small vehicle brake-by-wire technology is also constantly innovating and iterating, ushering in a new period of rapid development. As the core of the small vehicle brake-by-wire technology, the brake-by-wire technology is a difficult point, and it must be studied in depth to achieve a breakthrough. The small vehicle brake-by-wire device is the carrier of the brake-by-wire technology and the key point of the research content.

[0003] At present, the general small vehicle brake-by-wire device adopts a common electro-hydraulic brake module (such as IBS or EHB) on the market. When the automatic driving controller has a braking demand, specific braking instructions (deceleration or hydraulic pressure instructions) are sent to the electro-hydraulic brake module, and the electro-hydraulic brake module performs corresponding execution and feedbacks the execution. However, this scheme has the following problems: 1. The matching development of the electro-hydraulic brake module requires a large amount of manpower and cost, which is not suitable for the brake-by-wire vehicle development team in the early stage of entrepreneurship; 2. The electro-hydraulic brake module is a driving brake special part and does not have a parking function after parking, so in order to realize the brake-by-wire parking function, the vehicle development needs to additionally install a brake-by-wire parking module; 3. The mass of the electro-hydraulic brake module is about 7-10 kg, and the internal structure is difficult to simplify, which is not conducive to the weight reduction of the small vehicle; 4. The electro-hydraulic brake module occupies a space of about 8-15L, which occupies a large space and is not conducive to the internal arrangement of the small vehicle.

[0004] Therefore, it is necessary to develop a brake-by-wire device which is practical, simple in structure and control, to solve the problems existing in the brake-by-wire of the current small automatic driving vehicle and ensure the orderly development of other vehicle development work. SUMMARY

[0005] The application is to solve the problems existing in the prior art and provides a small vehicle brake-by-wire device and a braking method thereof.

[0006] The application adopts the following technical scheme: a small vehicle brake-by-wire device, comprising a transmission device and a control device;

[0007] The transmission device comprises a brake master cylinder, a brake master cylinder fixing support, a ball head top rod, a locking nut, a U-shaped push rod, a push rod motor fixing main support, a push rod motor fixing auxiliary support, a first pin shaft and a first split pin, and the control device comprises a push rod motor, a second pin shaft, a second split pin, an automatic driving controller, a vehicle controller, a fuse, a five-pin relay and an eight-pin relay;

[0008] The brake master cylinder comprises an oil inlet nozzle, a brake master cylinder piston and a hole elastic stop ring, the oil inlet nozzle is fixed on the oil inlet of the brake master cylinder, the brake master cylinder piston and the hole elastic stop ring are both arranged in the brake master cylinder, and the brake master cylinder piston is located on the inner side of the hole elastic stop ring.

[0009] The brake master cylinder is connected with the brake master cylinder fixing support through bolts, the ball head top rod is in contact with the brake master cylinder piston during work and separated from the brake master cylinder piston during non-work, the locking nut is connected with the ball head top rod through threads, the U-shaped push rod is connected with the ball head top rod through threads, the push rod motor is connected with the U-shaped push rod through a first pin shaft and a first split pin, the push rod motor fixed secondary support is connected with the push rod motor through a second pin shaft and a second split pin, and the push rod motor fixed primary support is connected with the push rod motor fixed secondary support through bolts.

[0010] The whole vehicle controller is connected with the five-pin relay and the eight-pin relay through a wire harness hard wire, the fuse is connected with the five-pin relay through the wire harness hard wire, and the push rod motor is connected with the eight-pin relay through the wire harness hard wire.

[0011] The automatic driving controller is connected with the whole vehicle controller through a CAN bus.

[0012] Further, the internal transmission structure of the push rod motor is a worm gear self-locking transmission mechanism.

[0013] Further, the brake master cylinder is selected from a center valve type, a plunger type or a compensation hole type.

[0014] Further, the oil inlet nozzle of the brake master cylinder is selected from a double oil nozzle interface.

[0015] Further, the gap between the ball head top rod and the brake master cylinder piston after separation is between 0.5 and 1.2 mm.

[0016] Further, the front end of the ball head top rod adopts a ball head structure.

[0017] Further, the connection between the ball head top rod and the U-shaped push rod adopts a two-section thread fastening mode.

[0018] Further, the locking nut is additionally installed on the ball head top rod and located at the front end of the U-shaped push rod.

[0019] The application also adopts the following technical scheme: a brake method of a brake-by-wire device for a small vehicle, and the brake-by-wire vehicle braking process is as follows:

[0020] The automatic driving controller sends a pressure building command to the whole vehicle controller according to the calculated braking demand.

[0021] The whole vehicle controller controls the five-pin relay and the eight-pin relay to connect the positive power supply contact according to the received brake hydraulic pressure instruction, and transmits the positive power supply to the push rod motor, and the push rod motor is positively rotated after receiving the positive power supply, and the U-shaped push rod and the ball head top rod are pushed forward, and the front end of the ball head top rod is in contact with the inner wall of the brake master cylinder piston, and the brake master cylinder piston is further pushed and pressed, and the corresponding hydraulic pressure is established in the brake pipeline, and the vehicle is slowed down or even stopped.

[0022] When the brake demand disappears, the whole vehicle controller controls the five-pin relay and the eight-pin relay to connect the reverse power supply contact, and transmits the reverse power supply to the push rod motor, and the push rod motor is reversely rotated after receiving the reverse power supply, and drives the U-shaped push rod and the ball head top rod to move backward, and the front end of the ball head top rod is separated from the inner wall of the brake master cylinder piston, and the hydraulic pressure established in the brake pipeline is released, and the vehicle braking force is eliminated.

[0023] Further, the line control parking brake process is as follows:

[0024] The automatic driving controller sends a vehicle parking instruction to the whole vehicle controller according to the demand.

[0025] The whole vehicle controller executes the parking action process: the whole vehicle controller controls the five-pin relay and the eight-pin relay to connect the positive power supply contact, and transmits the positive power supply to the push rod motor, and the push rod motor is positively rotated after receiving the positive power supply, and the push rod motor stroke reaches a certain position according to the calibrated power-on time, and the power supply is stopped, and the push rod motor maintains the stroke through the internal self-locking structure, so that the vehicle is parked.

[0026] The present application has the following beneficial effects:

[0027] (1) The line control brake device for small vehicles has the functions of line control driving brake and parking brake, has high function integration, and reduces the difficulty and development cost of line control chassis system module development of small automatic driving vehicles.

[0028] (2) The line control brake device for small vehicles has the functions of line control driving brake and parking brake, can receive the instruction sent by the automatic driving controller through the whole vehicle controller, and execute and feedback.

[0029] (3) The line control brake device for small vehicles has the function of line control parking brake, can automatically perform vehicle parking action after the vehicle is parked, and can feedback the state.

[0030] (4) The line control brake device for small vehicles contains a control device and a transmission device, which can be flexibly matched with different types of brake oil storage pots and brake actuators.

[0031] (5). The small-sized vehicle brake-by-wire device has simple hardware structure, relatively small mass and volume, and is convenient for vehicle weight reduction and arrangement.

[0032] (6). The small-sized vehicle brake-by-wire device has simple principle and control circuit, and does not need large manpower development investment, so that the vehicle development cycle and cost investment can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a partial structure schematic view of the small-sized vehicle brake-by-wire device.

[0034] Figure 2 It is another partial structure schematic view of the small-sized vehicle brake-by-wire device.

[0035] Figure 3 It is a control device schematic view. Figure 1

[0036] Figure 4 It is a control device schematic view. DETAILED DESCRIPTION

[0037] The application will be further described below in combination with the drawings.

[0038] As Figure 1 described, the small-sized vehicle brake-by-wire device comprises a transmission device and a control device, wherein the transmission device comprises a brake master cylinder 1, a brake master cylinder fixing support 2, a ball head top rod 3, a locking nut 4, a U-shaped push rod 5, a push rod motor fixing main support 6, a push rod motor fixing auxiliary support 7, a first pin shaft 9 and a first split pin 10, and the control device comprises a push rod motor 8, a second pin shaft 11, a second split pin 12, an automatic driving controller 100, a vehicle controller 200, a fuse 21, a five-pin relay 22 and an eight-pin relay 23.

[0039] The brake master cylinder 1 comprises an oil inlet nozzle 1-1, a brake master cylinder piston 1-2 and a hole elastic retainer 1-3, the oil inlet nozzle 1-1 is fixed on the oil inlet of the brake master cylinder 1, the brake master cylinder piston 1-2 and the hole elastic retainer 1-3 are both built-in in the brake master cylinder 1, the brake master cylinder piston 1-2 is located inside the hole elastic retainer 1-3, and in working, the two are separated and not in contact, and in non-working, the two are in contact.

[0040] ​Brake master cylinder 1 and brake master cylinder fixed support 2 are connected by bolts, ball head top rod 3 and brake master cylinder piston 1-2 are in contact during work and separated during non-work. Locking nut 4 is connected with ball head top rod 3 through thread, U-shaped push rod 5 is connected with ball head top rod 3 through thread, push rod motor 8 is connected with U-shaped push rod 5 through first pin shaft 9 and first open end pin 10, push rod motor fixed secondary support 7 is connected with push rod motor 8 through second pin shaft 11 and second open end pin 12, push rod motor fixed primary support 6 is connected with push rod motor fixed secondary support 7 through bolts.

[0041] Whole vehicle controller 200 is connected with five-pin relay 22 and eight-pin relay 23 through wire harness hard wire, fuse 21 is connected with five-pin relay 22 through wire harness hard wire, push rod motor 8 is connected with eight-pin relay 23 through wire harness hard wire.

[0042] Automatic driving controller 100 is connected with whole vehicle controller 200 through CAN bus.

[0043] Push rod motor 8 selects market general parts, and relative to specific vehicle models, 12V, 24V, 36V or 48V can be selected according to the whole vehicle power supply voltage; different push rod motor 8 total stroke, travel speed and thrust can be selected according to the brake system required liquid amount state and hydraulic pressure value demand.

[0044] The internal transmission structure of push rod motor 8 is a worm gear self-locking transmission mechanism, or other transmission mechanisms with self-locking function.

[0045] Brake master cylinder 1 can select center valve type, plunger type or compensation hole type. Among them, the selection of brake master cylinder 1 stroke should form a matching relationship with the stroke of push rod motor 8 to avoid the risk of push rod motor 8 stalling during travel.

[0046] The inlet nozzle 1-1 of the brake master cylinder 1 is preferably selected as a double oil nozzle interface, which can adapt to a double-channel or single-channel brake oil storage pot.

[0047] The installation of the elastic retainer 1-3 on the hole of the brake master cylinder 1 can avoid the accidental falling problem caused by the joint action of the brake master cylinder piston 1-2 and the ball head top rod 3 under the combined action of the brake pipeline hydraulic pressure and the brake master cylinder piston return spring after the continuous linkage, ensuring the reliability and durability of brake execution.

[0048] After the separation of the ball head top rod 3 and the brake master cylinder piston 1-2, the gap should be kept between 0.5-1.2mm to avoid residual hydraulic pressure in the brake pipeline and the brake oil cannot be effectively returned to the storage pot.

[0049] The front end of the ball head top rod 3 adopts a ball head structure to make the pushing pressure between the ball head top rod 3 and the brake master cylinder piston 1-2 more fully and uniformly.

[0050] The connection between the ball head top rod 3 and the U-shaped push rod 5 adopts a two-section threaded fastening mode, so as to avoid radial inclination of the ball head top rod 3 during force movement.

[0051] The locking nut 4 is additionally installed on the ball head top rod 3 and located at the front end of the U-shaped push rod 5, so as to avoid axial movement of the ball head top rod 3 during force movement.

[0052] The connection between the U-shaped push rod 5 and the push rod of the push rod motor 8 adopts a transition fit, so that the U-shaped push rod 5 and the push rod of the push rod motor 8 are connected in a straight line and do not produce large radial movement.

[0053] The push rod motor 8 is fixed by the push rod motor fixed main support 6 and the push rod motor fixed auxiliary support 7, so as to facilitate installation and disassembly of the push rod motor 8.

[0054] The push rod motor 8 and the push rod motor fixed auxiliary support 7 are connected by the first pin shaft 9 and the first split pin 10, and the push rod motor 8 and the U-shaped push rod 5 are connected by the second pin shaft 11 and the second split pin 12, so as to facilitate installation and disassembly.

[0055] The installation of the control circuit fuse 21 can effectively protect the brake-by-wire device and avoid occasional risks generated during testing and use.

[0056] The overall space occupation volume of the brake-by-wire device is about 3.5-4.5L, and the mass is 3-4kg, which belongs to the use category of small automatic driving vehicles, specifically small unmanned delivery vehicles / selling vehicles, cleaning vehicles, washing vehicles, low-speed interactive robots and the like.

[0057] The line braking process of the brake-by-wire device for small vehicles is as follows:

[0058] The automatic driving controller 100 sends a pressure building command to the vehicle controller 200 according to the calculated braking demand.

[0059] The whole vehicle controller 200 controls the five-pin relay 22 and the eight-pin relay 23 to connect the positive power supply contact, and transmits the positive power supply to the push rod motor 8 according to the received brake hydraulic pressure instruction. After receiving the positive power supply, the push rod motor 8 rotates in the positive direction, pushes the U-shaped push rod 5 and the ball head top rod 3 to move forward, the front end of the ball head top rod 3 contacts the inner wall of the brake master cylinder piston 1-2, and further pushes the brake master cylinder piston 1-2 to move forward and backward, so that the corresponding hydraulic pressure is established in the brake pipeline, and the vehicle is slowed down or even stopped. When the brake demand disappears, the whole vehicle controller 200 controls the five-pin relay 22 and the eight-pin relay 23 to connect the reverse power supply contact, and transmits the reverse power supply to the push rod motor 8. After receiving the reverse power supply, the push rod motor 8 rotates in the reverse direction, drives the U-shaped push rod 5 and the ball head top rod 3 to move backward, and the front end of the ball head top rod 3 is separated from the inner wall of the brake master cylinder piston 1-2, so that the hydraulic pressure established in the brake pipeline is removed, and the vehicle braking force is eliminated.

[0060] The wire control parking brake process of the wire control brake device for small vehicles is as follows:

[0061] The automatic driving controller 100 sends a vehicle parking instruction to the whole vehicle controller 200 according to the demand, or the whole vehicle controller 200 actively controls the wire control brake device to perform the vehicle parking action according to the monitored vehicle parking power-off state.

[0062] The whole vehicle controller 200 performs the parking action process: the whole vehicle controller 200 controls the five-pin relay 22 and the eight-pin relay 23 to connect the positive power supply contact, and transmits the positive power supply to the push rod motor 8. After receiving the positive power supply, the push rod motor 8 rotates in the positive direction, and the push rod motor 8 stops supplying power after the stroke reaches a certain position according to the specified power-on time, so that the vehicle is parked.

[0063] The push rod motor 8 positive and negative rotation control principle: the whole vehicle controller 200 controls the corresponding contacts of the relay through the low-side output pin, so as to realize the positive power supply, reverse power supply and stop power supply of the push rod motor 8, and make the push rod motor 8 rotate in the positive direction, reverse direction and stop rotating.

[0064] The positive power supply process of the push rod motor 8 is described: the whole vehicle controller 200 controls the pin 200-1 to output in the low side, so that the electromagnetic coil between the pin 22-4 and the pin 22-5 of the five-pin relay 22 is electrified to generate magnetic force, attract the contact, and then connect the pin 22-1 and the pin 22-2 of the five-pin relay 22 to supply 24V+ power to the pin 23-6 of the eight-pin relay 23.

[0065] The whole vehicle controller 200 controls the foot 200-1 to output low edge, and controls the foot 200-2 to output low edge at the same time, so that the electromagnetic coil between the foot 23-7 and the foot 23-8 of the eight-pin relay 23 is electrified to generate magnetic force, the contact is attracted, and then the foot 23-1 and the foot 23-6, the foot 23-2 and the foot 23-5 of the eight-pin relay 23 are connected at the same time, 24V+ electricity and 24V-electricity are supplied to the end of the push rod motor 8 in the forward direction, and the push rod motor is realized.

[0066] The process of reverse power supply of the push rod motor is described: the whole vehicle controller 200 controls the foot 200-1 to output low edge, so that the electromagnetic coil between the foot 22-4 and the foot 22-5 of the five-pin relay 22 is electrified to generate magnetic force, the contact is attracted, and then the foot 22-1 and the foot 22-2 of the five-pin relay 22 are connected, and 24V+ electricity is supplied to the foot 23-6 of the eight-pin relay 23.

[0067] The whole vehicle controller 200 controls the foot 200-1 to output low edge, and controls the foot 200-2 to output low edge at the same time, so that the electromagnetic coil between the foot 23-7 and the foot 23-8 of the eight-pin relay 23 is electrified to generate magnetic force, the contact is attracted, and then the foot 23-1 and the foot 23-6, the foot 23-2 and the foot 23-5 of the eight-pin relay 23 are connected at the same time, 24V+ electricity and 24V-electricity are supplied to the end of the push rod motor 8 in the forward direction, and the push rod motor is realized.

[0068] The process of stopping power supply of the push rod motor is described: the whole vehicle controller 200 controls the foot 200-1 to output low edge, so that the electromagnetic coil between the foot 22-4 and the foot 22-5 of the five-pin relay 22 is not electrified, the contact is in a natural state, the foot 22-1 and the foot 22-2 of the five-pin relay 22 are not connected, and 24V+ electricity is not supplied to the foot 23-6 of the eight-pin relay 23. Therefore, the push rod motor 8 cannot obtain power supply at this time, and is in a natural locking state.

[0069] The push rod stroke control method of the push rod motor 8: the push rod stroke of the push rod motor 8 is determined, and the control of the push rod stroke is realized by controlling the power supply time of the whole vehicle controller 200.

[0070] The relationship between the push rod stroke of the push rod motor 8 and the brake pipe hydraulic pressure: relative to a specific vehicle model, the brake pipe and the brake actuator are determined, and the required liquid amount state corresponding to the brake pipe hydraulic pressure value is within a certain theoretical range. According to the relationship between the push rod stroke of the push rod motor 8 and the liquid output of the brake master cylinder 1, the relationship curve between the push rod stroke of the push rod motor 8 and the brake pipe hydraulic pressure is calibrated:

[0071] The empirical formula of the relationship between the push rod stroke and the brake pipe hydraulic pressure:

[0072]

[0073] In the formula:

[0074] P: brake pipe pressure, Pa;

[0075] AV1, AV2: hydraulic pressure required amount of the first and second pipe, mm 3 ;

[0076] K: relationship coefficient between required amount and brake pipe pressure, Pa / mm 3 ;

[0077] S z , S 01 : push rod motor push rod stroke, push rod motor working idle stroke, mm;

[0078] d m : brake master cylinder diameter, mm.

[0079] The above only is the preferred embodiment of the present application, it should be pointed out that, for the ordinary skilled in the art, without departing from the principles of the present application can also be made several improvements, these improvements should also be considered as the protection scope of the present application.

Claims

1. A brake method of a small vehicle brake-by-wire device, the small vehicle brake-by-wire device comprising a transmission device and a control device; the transmission device comprising a brake master cylinder (1), a brake master cylinder fixing support (2), a ball head top rod (3), a locking nut (4), a U-shaped push rod (5), a push rod motor fixing main support (6), a push rod motor fixing secondary support (7), a first pin shaft (9), and a first split pin (10), and the control device comprising a push rod motor (8), a second pin shaft (11), a second split pin (12), an automatic driving controller (100), a vehicle control unit (200), a fuse (21), a five-pin relay (22), and an eight-pin relay (23); the brake master cylinder (1) comprising an oil inlet nozzle (1-1), a brake master cylinder piston (1-2), and a hole elastic retainer (1-3), the oil inlet nozzle (1-1) being fixed to the oil inlet of the brake master cylinder (1), the brake master cylinder piston (1-2) and the hole elastic retainer (1-3) being both built-in the brake master cylinder (1), and the brake master cylinder piston (1-2) being located inside the hole elastic retainer (1-3); the brake master cylinder (1) is connected with the brake master cylinder fixing support (2) through a bolt, the ball head top rod (3) is in contact with the brake master cylinder piston (1-2) when working and separated when not working, the locking nut (4) is connected with the ball head top rod (3) through a thread, the U-shaped push rod (5) is connected with the ball head top rod (3) through a thread, the push rod motor (8) is connected with the U-shaped push rod (5) through the first pin shaft (9) and the first split pin (10), the push rod motor fixing secondary support (7) is connected with the push rod motor (8) through the second pin shaft (11) and the second split pin (12), and the push rod motor fixing main support (6) is connected with the push rod motor fixing secondary support (7) through a bolt; The whole vehicle controller (200) is connected with the five-pin relay (22) and the eight-pin relay (23) through a wire harness hard wire, the fuse (21) is connected with the five-pin relay (22) through a wire harness hard wire, and the push rod motor (8) is connected with the eight-pin relay (23) through a wire harness hard wire, characterized in that: the line control parking brake process is as follows: the vehicle control unit (200) controls the five-pin relay (22) and the eight-pin relay (23) to connect the positive power supply contact according to the received brake hydraulic pressure instruction and the calibrated power-on time, and transmits the positive power supply to the push rod motor (8), the push rod motor (8) is positively rotated after receiving the positive power supply, pushes the U-shaped push rod (5) and the ball head top rod (3) forward, the front end of the ball head top rod (3) is in contact with the inner wall of the brake master cylinder piston (1-2), and further pushes the brake master cylinder piston (1-2) to establish the corresponding hydraulic pressure in the brake pipeline, so as to realize the vehicle deceleration or even parking; when the brake demand disappears, the vehicle control unit (200) controls the five-pin relay (22) and the eight-pin relay (23) to connect the reverse power supply contact, and transmits the reverse power supply to the push rod motor (8), the push rod motor (8) is reversely rotated after receiving the reverse power supply, drives the U-shaped push rod (5) and the ball head top rod (3) to move backward, the front end of the ball head top rod (3) is separated from the inner wall of the brake master cylinder piston (1-2), the hydraulic pressure established in the brake pipeline is removed, and the vehicle brake force is eliminated; the line control parking brake process is as follows: The whole vehicle controller (200) executes the parking action process: the whole vehicle controller (200) controls the five-pin relay (22) and the eight-pin relay (23) to make the forward power supply contact connected, and transmits the forward power supply to the push rod motor (8), the push rod motor (8) is positively rotated after receiving the forward power supply, and the power supply is stopped after the stroke of the push rod motor (8) reaches a certain distance according to the calibrated power-on time, and the push rod motor (8) keeps the stroke through the internal self-locking structure, so that the vehicle is parked.

2. The brake method for a small-sized vehicle brake-by- wire apparatus according to claim 1, characterized by: The connection between the ball head top rod (3) and the U-shaped push rod (5) adopts a two-section threaded fastening mode.

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