Drum brake type electromagnetic and friction hybrid braking device for electric vehicle

Abstract

The invention relates to the technical field of electric vehicle drum brakes, and discloses a drum brake type electromagnetic and friction hybrid braking device for an electric vehicle, a friction braking unit of the drum brake type electromagnetic and friction hybrid braking device is provided with a brake drum connected to a power source to rotate, brake pads sequentially arranged in the brake drum and two brake shoes symmetrically arranged, the brake cylinder is arranged between the two brake shoes, and the round drum is arranged on the outer side of the brake drum. The control unit is provided with a voltage regulating module which is connected with and controls the brake handle and the electromagnetic brake unit to control the working state of the controller. The number of the electromagnetic braking units is four, and the electromagnetic braking units are symmetrically arranged on the round drum. The hybrid braking device is simple in structure, high in practicability and high in braking reliability, the response speed and sensitivity of the brake drum and the brake pad can be improved while stable braking is kept, and meanwhile the heat dissipation performance and wear resistance of the whole braking device can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle drum brakes, in particular to a drum brake type electromagnetic and friction hybrid brake device for electric vehicles. Background Art

[0002] The statements in this section merely provide background art related to the present disclosure and do not necessarily constitute prior art.

[0003] The brake device is a device that converts the kinetic energy of a moving vehicle into heat energy to slow down the vehicle. Disc brakes produce braking by clamping the brake disc with friction pads. Drum brakes produce braking by pressing the friction pads against the inside of the rotating brake drum. Both braking methods generate a lot of friction heat. The main disadvantages of using friction brakes alone are: ① Wear: Long-term use of friction brakes will cause wear of the friction material, which needs to be replaced regularly, otherwise the braking force will be reduced and noise may be generated. ② Braking noise: As mentioned above, when the friction coefficient is too high, especially under certain conditions, obvious braking noise may be generated, which not only affects driving comfort, but may also interfere with driving safety. ③ Expansion problem: During braking, due to thermal expansion and contraction, metal parts may expand, resulting in a decrease in the accuracy of the braking system, and long-term high temperature may cause deformation of parts. ④ Winter performance: At low temperatures, the performance of friction materials will decrease, especially on icy roads, and the braking force may be significantly weakened.

[0004] At present, two-wheeled electric vehicles (hereinafter referred to as electric vehicles) have become the mainstream means of transportation for Chinese citizens, which is particularly convenient for short-distance travel. However, the braking principle of electric vehicles is single, and accidents often occur due to braking problems. Electric vehicles use drum brakes, which may have advantages in cost and initial installation, but in the long run, drum brakes may have potential hazards in some aspects: ① The heat dissipation performance of drum brakes is relatively weak. Frequent or high-speed braking may cause the brake pads to overheat, affecting the durability of the braking force, especially in high temperature environments, which may cause brake degradation.

[0005] ② Wear problem: The brake pad material of drum brakes is easy to wear and needs to be replaced regularly, which has high maintenance costs. In addition, asbestos brake pads are controversial in terms of environmental protection.

[0006] ③Control stability: Since the braking force is not linear, the driver may need more delicate operations to maintain stable braking. Novice or impatient drivers may encounter control difficulties.

[0007] ④ Safety hazards: Although it is a safety design in itself, under extreme conditions or long-term high-load use, the drum brake may have insufficient braking force, affecting emergency braking response, especially in urban traffic that requires instantaneous large-scale deceleration. Summary of the invention

[0008] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a drum brake electromagnetic and friction hybrid brake device for electric vehicles, which installs a friction brake unit and an electromagnetic brake unit together and controls them separately through a control unit to achieve hybrid braking. On the one hand, rapid braking can be achieved, and on the other hand, the response speed of the brake drum and brake pads can be improved, thereby improving the sensitivity of the brakes. At the same time, invalid contact can be avoided, and the heat dissipation performance and wear resistance of the brake pads can be improved.

[0009] The technical solution adopted by the present invention is: a drum brake type electromagnetic and friction hybrid brake device for electric vehicles, having: A friction brake unit, the friction brake unit has a brake drum connected to a power source for rotation, a brake pad arranged in sequence in the brake drum and two symmetrically arranged brake shoes, a brake cylinder arranged between the two brake shoes for driving the brake shoe and the brake pad to approach or move away from the inner wall of the brake drum, and a round drum arranged on the outside of the brake drum; and a control unit, the control unit has a pressure regulating module, the pressure regulating module is connected to and controls the brake handle and the electromagnetic brake unit to control the working state; and an electromagnetic brake unit, the electromagnetic brake unit has four, which are symmetrically arranged on the round drum.

[0010] In this solution, each electromagnetic brake unit comprises: a stainless steel shell, an iron core and a coil encapsulated therein in sequence, an aluminum alloy outer cover buckled on the stainless steel shell, and a coil lead for connecting to a voltage regulating module.

[0011] In this embodiment, at least one return spring 9 is provided between the two brake shoes of the friction brake unit, and an even symmetrical number of two, four, six, etc. can also be provided to improve its restoring ability, further reduce the friction between the brake pad and the brake shoe, and thereby improve the heat dissipation capacity of the brake device.

[0012] In this solution, the voltage regulating module has: a power supply terminal for connecting to the vehicle battery to obtain power, an output terminal for connecting each coil lead, and a control terminal; wherein: the AV and GND ends of the control terminal are connected in parallel to the variable resistance trigger of the brake handle and the switch tube drive circuit to drive the switch tube k2, and the variable resistance trigger and the switch tube k2 are connected in parallel and then connected in series with a fixed resistor, and the switch tube k2 is also connected to the pulse generating module, and one end of the switch tube drive circuit and the pulse generating module is also connected in series with a normally open contact k1 for controlling the conduction of the pulse generating module and the switch tube drive circuit. electrical state; at the same time, when the brake handle has been pulled to the limit, the limit switch contacts the handlebar, closing the normally open contact k1. When the switch tube k2 is turned on, it is used to short-circuit the variable resistance trigger, so that the voltage between the output terminal a and the output terminal b of the variable resistance trigger is zero, thereby making the voltage across AV and GND of the voltage regulating module zero, and finally making the output voltage of the voltage regulating module zero; when the switch tube k2 is disconnected, the voltage across AV and GND of the voltage regulating module is the divided voltage of the variable resistance trigger in the circuit; when the switch tube k2 is continuously turned on and off at a certain frequency under the action of the pulse signal, an electromagnetic pulse brake will be formed.

[0013] In the present solution, the brake handle is connected to a variable resistance trigger, which comprises: a circular rheostat having an output end a and an output end b; a pull rod with one end connected to the center of the circular rheostat; and a spring with one end fixed to the other end of the pull rod to reset the pull rod. In a specific implementation, one end of the spring is fixedly connected to the pull rod, and the other end is fixed at a position that ensures that the pull rod can be opened to change its position between the output end a and the output end b of the circular rheostat and can be reset normally.

[0014] In this solution, the normally open contact k1 is a limit switch connected to the brake handle, that is, the normally open contact k1 of the limit switch corresponds to k1 in the figure. When the brake handle has been pulled to the limit, the limit switch will contact the handlebar and the normally open contact k1 will close.

[0015] In this solution, the control unit is arranged near the mounting hole of the brake handle close to the front of the electric vehicle.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) High reliability, high heat dissipation and long life: The friction brake unit and the electromagnetic brake unit are installed together and controlled separately by the control unit. Compared with a single friction brake, the combination of electromagnetic brake and friction brake has a longer service life and lower failure rate, reducing maintenance requirements.

[0017] (2) Environmental protection and economy: The electromagnetic brake unit can share the vehicle's braking load, extend the life of the friction brake, reduce maintenance costs, and is conducive to energy conservation and emission reduction, which is in line with the trend of green travel.

[0018] (3) Simple structure and strong practicality. Although the initial purchase cost is high, compared with traditional friction brakes, it has stronger braking effect, improved driving comfort and greater reliability.

[0019] (4) Fast response speed: When rapid braking is required, the electromagnetic brake can quickly adjust the braking force to ensure dynamic performance and safety.

[0020] To sum up, the drum brake type electromagnetic and friction hybrid braking device for electric vehicles of the present invention, on the one hand, has a simple structure, strong practicality, and high braking reliability; on the other hand, while maintaining stable braking, it can improve the response speed of the brake drum and brake pads, thereby improving the sensitivity of the brake, and at the same time can avoid invalid contact, thereby improving the heat dissipation performance and wear resistance of the brake pads and the entire braking device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a single-wheel external hybrid drum brake device; Figure 2 This is a schematic diagram of the handbrake; Figure 3 It is a schematic diagram of the electromagnetic brake unit; Figure 4 is a schematic diagram of a control unit; Figure 5 This is the schematic diagram of the variable resistance trigger; Figure 6 It is a schematic diagram of the structure of the variable resistance trigger; Figure 7 It is a schematic diagram of a single-wheel internal hybrid drum brake device; Figure 8 for Figure 1 Side view of Brake handle, 11-limit switch, 12-mounting hole; Friction brake unit, 21-brake drum, 22-brake pad, 23-brake shoe, 24-brake cylinder, 25-round drum, 26-return spring, 27-guide block; 30-control unit, 31-voltage regulating module, 32-pulse generating module, 33-switching tube driving circuit, 34-fixed resistor; 40-electromagnetic brake unit, 41-stainless steel housing, 42-iron core, 43-coil, 44-aluminum alloy outer cover, 45-coil lead wire; 50-variable trigger, 51-round variable resistor, 52-pull rod, 53-spring. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0023] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right" and the like indicate positions or positional relationships based on the positions 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 combination or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, in the description of the embodiments of the present invention, the device positional relationships such as "up", "down", "front", "back", "left", "right" and the like in all the drawings are based on the positions or positional relationships shown in the accompanying drawings. Figure 1 As standard.

[0024] like Figure 1 and Figure 8 As shown, the drum brake type electromagnetic and friction hybrid brake device for electric vehicles has: A friction brake unit 20, the friction brake unit 20 has a brake drum 21 connected to a power source for rotation, a brake pad 22 arranged on the brake drum 21 in sequence and two brake shoes 23 arranged symmetrically, and a brake cylinder 24 arranged between the two brake shoes 23 for driving the brake shoes 23 and the brake pad 22 to approach or move away from the inner wall of the brake drum 21, and a round drum 25 arranged on the outer side of the brake drum 21; and a control unit 30, the control unit 30 has a pressure regulating module 31, the pressure regulating module 31 is connected to and controls the brake handle 10 and the electromagnetic brake unit 40 to be in a controller working state; and an electromagnetic brake unit 40, the electromagnetic brake unit 40 has four, and is symmetrically arranged on the round drum 25. The hybrid brake device centrally installs the friction brake unit 20 and the electromagnetic brake unit 40 together, and controls them respectively through the control unit 30, which can realize rapid braking on the one hand, and improve the corresponding speed of the brake drum 21 and the brake pad 22 on the other hand, thereby improving the sensitivity of the brake, and can avoid invalid contact, and improve the heat dissipation performance and wear resistance of the brake pad.

[0025] In a specific implementation process, the end faces of the four electromagnetic brake units 40 may not be in contact with the brake drum 21 , so the heat dissipation effect is better.

[0026] In at least one embodiment, Figure 3As shown, each electromagnetic brake unit 40 comprises: a stainless steel shell 41, and an iron core 42 and a coil 43 encapsulated therein in sequence, and an aluminum alloy outer cover 44 fastened to the stainless steel shell 41, and a coil lead 45 for connecting to the voltage regulating module 31, so as to realize efficient connection to the control unit 20 and better realize electromagnetic braking. In addition, it should be noted that the power supply of the electromagnetic brake unit 40 comes from the vehicle battery.

[0027] In at least one embodiment, Figure 1 and Figure 7 As shown, at least one return spring 26 is provided between the two brake shoes 23 of the friction brake unit 20, and an even symmetrical number of two, four, six, etc. can also be provided to improve its restoring ability, further reduce the friction between the brake pad and the brake shoe, and thus improve the heat dissipation capacity of the brake device.

[0028] In at least one embodiment, Figure 4 As shown, the voltage regulating module 31 has: a power terminal for connecting to the vehicle battery to obtain power, an output terminal for connecting each coil lead 45, and a control terminal; the AV and GND2 ends of the control terminal are connected in parallel to the variable resistance trigger of the brake handle 10 and the switch tube driving circuit 33 to drive the switch tube k2, combined with Figure 1 , Figure 7 and Figure 4 At the same time, the variable resistance trigger 50 and the switch tube k2 are connected in parallel and then in series with the fixed resistor 34, and the switch tube k2 is also connected to the pulse generating module 32, and the normally open contact k1 is also connected in series at one end of the switch tube driving circuit 33 and the pulse generating module 32, which is used to control the power-on state of the pulse generating module 32 and the switch tube driving circuit 33; at the same time, when the brake handle 10 has been pulled to the limit, the limit switch 11 contacts the handlebar to close the normally open contact k1, and when the switch tube k2 is turned on, it is used to short-circuit the variable resistance trigger 50, so that the voltage between the output end a and the output end b of the variable resistance trigger 50 is zero, so that the voltage between the AV and GND2 ends of the voltage regulating module is zero, and finally the output voltage of the voltage regulating module is zero; when the switch tube k2 is disconnected, the voltage between the AV and GND2 ends of the voltage regulating module is the divided voltage of the variable resistance trigger in the circuit; when the switch tube k2 is continuously turned on and off at a certain frequency under the action of the pulse signal, an electromagnetic pulse braking will be formed.

[0029] In the specific implementation process, the pulse generating module 32 can adopt the common N555 pulse generating module on the market, and the voltage regulating module 31 can purchase a ready-made DC-DC module on the market, such as a voltage regulating module with a voltage of 13-100V input and 5-48V output; the selection of the switch tube driving circuit 33 needs to be determined according to the selection of the switch tube k2. If k2 is a MOSFET tube, the MOSFET driving module of Shenzhen Mingyuan Dingye Technology can be selected.

[0030] The power terminal of the voltage regulator module 31 is connected to the vehicle battery, and the output terminal is connected to Figure 3 The coil lead 45 is used to supply power to each electromagnetic brake unit 40. In order to ensure the safety of the coil 43, a current limiting resistor of about 5 ohms needs to be connected in series in the power supply circuit of the coil 43.

[0031] In at least one embodiment, Figure 2 As shown, the brake handle 10 is connected to a variable resistance trigger 50. Figure 6 As shown, the variable resistor trigger 50 comprises: a circular variable resistor 51 having an output terminal a and an output terminal b; a pull rod 52 with one end connected to the center of the circular variable resistor 51; and a spring 53 with one end fixed to the other end of the pull rod 52 to reset the pull rod 52. In a specific implementation, one end of the spring 53 is fixedly connected to the pull rod 52, and the other end is fixed to a position that ensures that the pull rod 52 can be opened to change its position between the output terminal a and the output terminal b of the circular variable resistor 51, and can be reset normally.

[0032] In at least one embodiment, see Figure 2 The normally open contact k1 is connected to the limit switch 11 on the brake handle 10, that is, the normally open contact k1 of the limit switch 11 corresponds to Figure 5 In k1, when the brake handle 10 has been pulled to the limit, the limit switch 11 will contact the handlebar and the normally open contact k1 will close.

[0033] like Figure 5 , Figure 6 As shown, the variable resistance trigger 50 is essentially a variable resistor, and can adopt the RV24YN20S potentiometer commonly available in the market. Figure 5 The output terminal a and the variable resistor output terminal b correspond to Figure 6 When the driver gradually tightens the variable resistance trigger 50 with his finger, the circular variable resistor 51 rotates with the pull rod 52, and the resistance between a and b gradually increases from zero; when the driver releases his finger, the pull rod 52 returns to its original position under the action of the spring 53, and the resistance between a and b returns to zero.

[0034] When the electric vehicle is running normally and the driver does not touch the variable resistance trigger 50 and the brake handle 10, no braking occurs; when the driver lightly holds the variable resistance trigger with his index finger and does not tighten the brake handle 10, the system will gradually increase the electromagnetic braking as the tightening degree of the variable resistance trigger gradually increases; if the driver tightens the brake handle with his fingers, the friction brake will be put into use; if the driver tightens the variable resistance trigger 50 and the brake handle 10 at the same time, the electromagnetic brake unit 40 and the friction brake unit 20 will be put into use at the same time; when the driver has pulled the brake handle 10 to the limit, that is, the brake handle 10 has touched the handlebar and caused the limit switch 11 to be triggered, the friction brake unit 20 and the electromagnetic brake unit 40 work at the same time, and the electromagnetic brake unit 40 is periodically energized for electromagnetic braking.

[0035] In at least one embodiment, the control unit 30 is disposed near the brake handle 10 and near the mounting hole 12 of the front of the electric vehicle. Figure 2 It can be shown that the connection structure is more convenient to control.

[0036] In at least one embodiment, a vertical guide block 27 is provided at the center between the two brake shoes 23 to ensure that the two brake shoes 23 move along a fixed straight line under the action of hydraulic pressure, thereby reducing friction on the brake pads and thus reducing the heat dissipation burden.

[0037] In at least one embodiment, the drum 25 can be arranged on the outside or inside of the electromagnetic brake unit 40. Figure 1 In the embodiment shown, the drum 25 is placed outside the electromagnetic brake unit 40, which has a good heat dissipation effect and does not require modification of the original drum brake.

[0038] like Figure 7 As shown, the hybrid drum brake device can be built-in, and the electromagnetic brake unit 40 is built-in in the internal space of the brake drum 21 and is installed on the guide block 27 respectively. This built-in method saves space, but the heat dissipation effect is relatively poor, and the original drum brake needs to be modified. The specific modification is that the electromagnetic brake unit 40 needs to pass through the brake shoe 23 and the brake pad 22.

[0039] You can choose one of the above two methods, and the rest of the components such as the brake handle and control unit are the same. The main difference between the two is that the external method can place more electromagnetic brake units and has good heat dissipation, but it will increase the volume; the internal method will reduce the number of electromagnetic brake units, the volume is relatively small, and the heat dissipation is not as good as the external method.

[0040] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A drum brake type electromagnetic and friction hybrid brake device for electric vehicles, characterized in that: have: A friction brake unit (20), the friction brake unit (20) comprising a brake drum (21) connected to a power source for rotation, a brake pad (22) sequentially arranged in the brake drum (21) and two symmetrically arranged brake shoes (23), and a brake cylinder (24) arranged between the two brake shoes (23) for driving the brake shoes (23) and the brake pad (22) to approach or move away from the inner wall of the brake drum (21); and Drum (25); and A control unit (30), the control unit (30) having a voltage regulating module (31), the voltage regulating module (31) being connected to and controlling the brake handle (10) and the electromagnetic brake unit (40) to be in a controller working state; and An electromagnetic braking unit (40), wherein the electromagnetic braking units (40) have four and are symmetrically arranged on the drum (25).

2. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 1, characterized in that: Each of the electromagnetic braking units (40) has: stainless steel housing (41), and An iron core (42) and a coil (43) are sequentially encapsulated therein, and an aluminum alloy outer cover (44) buckled onto the stainless steel outer shell (41), and A coil lead (45) is used to connect to the voltage regulating module (31).

3. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 2, characterized in that: At least one return spring (26) is provided between the two brake shoes (23) of the friction brake unit (20).

4. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 3, characterized in that: The voltage regulating module (31) comprises: The power terminal for connecting to the vehicle battery to obtain power, and Connect each coil lead (45) to the output terminal, and Control terminal; Wherein: the AV and GND2 ends of the control end are connected in parallel to the variable resistance trigger of the brake handle (10) and the switch tube drive circuit (33) to drive the switch tube k2, and the variable resistance trigger (50) and the switch tube k2 are connected in parallel and then connected in series with the fixed resistor (34), and the switch tube k2 is also connected to the pulse generation module (32); and a normally open contact k1 is also connected in series at one end of the switch tube drive circuit (33) and the pulse generation module (32) to control the power-on state of the pulse generation module (32) and the switch tube drive circuit (33).

5. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 4, characterized in that: The brake handle (10) is connected to a variable resistance trigger (50), and the variable resistance trigger (50) has: a circular varistor (51) having an output terminal a and an output terminal b; and A pull rod (52) having one end connected to the center of the circular rheostat (51); and A spring (53) having one end fixed to the other end of the pull rod (52) for returning the pull rod (52) to its original position.

6. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 5, characterized in that: The normally open contact k1 is a limit switch (11) connected to the brake handle (10).

7. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 5, characterized in that: The control unit (30) is arranged on the brake handle (10) near the mounting hole (12) on the front of the electric vehicle.

8. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 5, characterized in that: A vertical guide block (27) is respectively arranged at the center portion between the two brake shoes (23).

9. The drum brake type electromagnetic and friction hybrid brake device for electric vehicles according to claim 5, characterized in that: The drum (25) is arranged on the outside or inside of the electromagnetic brake unit (40).

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