Electric control brake electromagnetic drive device for electric vehicle

Abstract

The utility model discloses a kind of electromagnetism driving devices of electric control brake of electric vehicle, including electromagnet and the brake oil passage and oil cavity of intercommunication being arranged in caliper body.In the caliper body, upper armature and lower armature are movably arranged in the opposite sides of electromagnet, large plunger is connected on the upper armature, small plunger is connected on the lower armature, and the diameter of small plunger is less than the diameter of large plunger and piston;Large return spring acts on large plunger, and small return spring acts on small plunger;Large plunger is arranged on brake oil passage, and small plunger is used for acting with brake oil in oil cavity;One-way stop valve is arranged on brake oil passage, and located between large plunger and oil cavity, for brake oil positive direction conduction, reverse cut-off;Further include pressure relief passage being arranged in caliper body and pressure relief valve being arranged on pressure relief passage, and pressure relief passage is connected with brake oil passage.

Description

Technical Field

[0001] This utility model relates to an electronically controlled braking system for electric vehicles, and more particularly to an electromagnetic drive device in an electronically controlled braking system. Background Technology

[0002] All vehicles require a braking system to brake the vehicle as needed during driving. The main structure of the braking system includes a caliper, which comprises a caliper body. A pair of brake pads are movably mounted on the caliper body. The brake pads are moved by brake fluid, which is pressurized and depressurized by a hydraulic pump. Existing braking systems of this type have relatively high manufacturing costs, and the brake pad response is relatively slow.

[0003] Chinese patent document (authorization announcement number: CN 218093982U) discloses an electromagnet hydraulic brake mechanism, belonging to the technical field of hydraulic brake mechanisms. The structure includes a lower hydraulic brake valve, to which a hydraulic brake oil pipe is fixedly connected. An upper hydraulic brake valve is fixedly connected to the end of the hydraulic brake oil pipe away from the lower valve. A control mechanism is movably connected to the end of the upper hydraulic brake valve away from the hydraulic brake oil pipe. The control mechanism includes a plunger switch fixedly mounted on the upper hydraulic brake valve. The output end of the plunger switch is magnetically connected to an electromagnet control unit. An electromagnet A, an electromagnet B, and an electromagnet mounting plate are sequentially arranged inside the electromagnet mounting base on the side away from the plunger switch. This mechanism allows the operator to quickly switch between releasing and braking states of the hydraulic brake without manual or foot control during operation, simplifying the operation process and greatly increasing operational safety.

[0004] This braking mechanism requires two electromagnets, resulting in relatively poor overall structural compactness and relatively complex control. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide an electric vehicle electronically controlled brake electromagnetic drive device with good overall compact structure.

[0006] To solve the aforementioned technical problem, the present invention provides the following technical solution: an electromagnetic drive device for electric vehicle electronic brakes, comprising an electromagnet disposed within a caliper body and a communicating brake fluid passage and oil chamber. The device is characterized in that an upper armature and a lower armature are movably disposed on opposite sides of the electromagnet within the caliper body. A large plunger is connected to the upper armature, and a small plunger is connected to the lower armature. The diameter of the small plunger is smaller than the diameters of the large plunger and the piston. One end of a large return spring is fixed relative to the electromagnet, and the other end of the large return spring acts on the large plunger. One end of a small return spring is fixed relative to the electromagnet, and the other end of the small return spring acts on the small plunger. The large plunger is disposed in the brake fluid passage, and the small plunger interacts with the brake fluid in the oil chamber. A one-way shut-off valve is installed in the brake fluid passage and located between the large plunger and the oil chamber. It is used to allow the brake fluid to flow in the forward direction and shut off the flow in the reverse direction. It also includes a pressure relief passage located inside the caliper body and a pressure relief valve located on the pressure relief passage, the pressure relief passage being connected to the brake fluid passage.

[0007] Brake pads are fixed to the piston. A reservoir on the caliper body stores brake fluid. Brake fluid is the medium that transmits force and pressure during braking. The brake fluid passage allows brake fluid to flow from the reservoir to the brake chamber. In the electromagnetic drive device, the electromagnet generates magnetic attraction when energized, causing the upper and lower armatures to overcome the spring force of their respective return springs and move towards the electromagnet. The upper and lower armatures may not ultimately make contact with the electromagnet; as the spring compression increases, a certain distance is maintained between the upper and lower armatures and the electromagnet. The appropriate spring specification can be selected based on actual usage requirements and the electromagnet's operating parameters.

[0008] When the electromagnet is energized, the upper and lower armatures simultaneously drive the large and small plungers to move. The large plunger pushes the brake fluid forward through the one-way valve into the oil chamber, while the small plunger moves, increasing the volume of the oil chamber. When the electromagnet is de-energized, the large and small return springs cause the large and small plungers to move away from the electromagnet, causing the small plunger to push the brake fluid in the oil chamber to achieve braking. After braking is completed, the pressure relief valve is activated, connecting the oil tank and the oil chamber through the pressure relief passage. Once the pressure of the brake fluid in the oil tank and the oil chamber is equal, the pressure relief valve cuts off the pressure relief passage.

[0009] The pressure relief passage allows brake fluid to flow from the oil chamber to the reservoir, while the pressure relief valve controls the opening and closing of this passage. Under normal circumstances, the pressure relief passage is closed by the valve; it only opens when it is necessary to release pressure from the brake fluid in the oil chamber. The duration for which the pressure relief valve opens the passage can be set according to actual conditions and can be determined through testing to find the time required for complete pressure release.

[0010] Furthermore, the caliper body is equipped with an oil reservoir, and the brake fluid passage passes through a large plunger. A one-way structure is provided on the large plunger, through which the brake fluid passage passes. When the large plunger moves towards the electromagnet, the one-way structure closes, cutting off the flow of brake fluid; when the large plunger moves away from the electromagnet, the one-way structure opens, allowing brake fluid to flow from the reservoir towards the oil chamber. Alternatively, the large plunger can be located outside the brake fluid passage, with a one-way shut-off structure upstream of the large plunger. The large plunger communicates with the brake fluid passage and can pressurize the brake fluid within it. By having the brake fluid passage pass through the large plunger and incorporating the one-way structure, the overall structure becomes compact, facilitating the pressurization of the brake fluid and allowing it to smoothly enter the oil chamber.

[0011] Furthermore, a hollow inner core is provided on the electromagnet, through which the brake oil passage passes, and the one-way structure is located between the inner core and the large plunger. The inner core provides a structural basis for the upper and lower armatures and their corresponding springs, and facilitates the installation of the large and small plungers. The overall structure is robust, ensuring smooth operation of the corresponding components.

[0012] Furthermore, the bottom wall of the oil reservoir is provided with a connecting hole, in which the large plunger is slidably and fluid-tightly inserted; an oil hole is provided inside the large plunger, which serves as part of the brake fluid passage. The oil hole generally penetrates the large plunger axially, allowing the large plunger to be directly inserted into the oil reservoir, facilitating the flow of brake fluid from the reservoir into the large plunger, resulting in a simple structure.

[0013] Furthermore, a stop valve needle is protruding from the top of the inner core corresponding to the position of the oil hole. The stop valve needle is used to engage with or disengage from the oil hole, and the stop valve needle and the oil hole constitute the unidirectional structure. This unidirectional structure is convenient to set up, simple in structure, and can well adapt to the movement of the large plunger to cut off and guide the brake fluid, making it convenient for the large plunger to press the brake fluid into the oil chamber.

[0014] Furthermore, a pressurizing chamber is provided on the upper end face of the inner core, and the lower end of the large plunger is slidably inserted into the pressurizing chamber, through which the brake fluid passage passes. Functionally, combined with the aforementioned unidirectional structure, the large plunger can pressurize the brake fluid within the pressurizing chamber, allowing the brake fluid to smoothly enter the oil chamber. Structurally, the large plunger and the inner core can be coaxially arranged, thus achieving good overall structural compactness while ensuring the brake fluid flows as required.

[0015] Further, the inner core is in an inverted "convex" shape, so that a convex shoulder is formed between the large end and the small end of the inner core, and one end of the small return spring abuts against the convex shoulder; the pressure cavity is arranged in the large end of the inner core, and one end of the large return spring abuts against the bottom surface of the pressure cavity. Through the shape configuration of the inner core, the arrangement of the large and small return springs is facilitated, which well adapts to the movement requirements of the upper armature and the lower armature.

[0016] Further, the caliper body and the oil storage tank are respectively fixedly connected to opposite side surfaces of the housing, an upper space for the movement of the upper armature is formed between the oil storage tank and the housing, and a lower space for the movement of the lower armature is formed between the housing and the caliper body; two ends of the large plunger are respectively slidably penetrated through the wall bodies of the oil storage tank and the housing that are close to each other, and the small plunger is slidably penetrated through the wall body of the housing facing the caliper body. By arranging the housing and arranging the electromagnet inside the housing, the overall structure has good compactness, which is convenient for the large plunger and the small plunger to generate corresponding motions under the action of the electromagnet and the springs, so as to meet actual working requirements.

[0017] Further, the oil cavity opens toward the housing, the wall body of the housing facing the caliper body sealingly covers the opening of the oil cavity, one end of the inner core abuts against the inner surface of the wall body of the housing, a through hole is arranged on the wall body, the through hole communicates the inside of the inner core with the oil cavity, and the brake oil passage passes through the through hole; the small plunger passes through the wall body. The wall body of the housing is directly used to sealingly cover the opening of the oil cavity, which is beneficial for the small plunger to act on the brake oil in the oil cavity, so that the brake pad can bite and brake the side surface of the brake disc.

[0018] Further, a cut-off cavity is arranged in one end of the inner core facing the oil cavity, a plurality of inclined holes penetrating to the cut-off cavity are arranged on the other end surface of the inner core, a cut-off spring and a cut-off ball are arranged in the cut-off cavity, the cut-off ball is pressed by the cut-off spring to cover the outlets of the inclined holes, and the cut-off ball and the cut-off spring form the one-way cut-off valve. The one-way cut-off valve has simple structure, is convenient to process, is convenient to realize forward conduction and reverse cut-off of brake oil, and has good use stability.

[0019] Compared with existing technologies, this utility model has the following advantages: In this electronically controlled brake electromagnetic drive device, a large plunger is used to pressurize and push the brake fluid into the oil chamber. With the one-way shut-off valve and pressure relief passage cut off, the oil chamber acts as a sealed body. When the small plunger acts on the brake fluid, the brake fluid in the closed state within the oil chamber can transmit the pressure applied by the small plunger to the brake pads, thus providing stable braking to the brake disc. The structure is simple and the operation is reliable. By using a single electromagnet with upper and lower armatures on opposite sides of the electromagnet, combined with corresponding return springs, the overall design is compact, effectively meeting the requirements for brake pad control. It occupies a small volume, is easy to install, and facilitates electronic control.

[0020] The reservoir, housing, and caliper body are rigidly connected together, resulting in a compact structure. This design shortens the brake fluid flow path and accelerates its response. Furthermore, it eliminates the need for external hoses to connect the components, preventing pressure loss due to hose expansion during operation and ensuring smooth brake fluid flow throughout the system. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of the electromagnetic drive device in use, with the electromagnet not activated.

[0022] Figure 2 yes Figure 1 Enlarged view of part A in the image.

[0023] Figure 3 yes Figure 1 Enlarged view of part B in the image.

[0024] Figure 4 This is a cross-sectional view of another operating state of this electromagnetic drive device, in which the electromagnet is energized and started.

[0025] Figure 5 yes Figure 4 Enlarged view of section C in the image.

[0026] In the diagram, 1. Controller; 2. Oil reservoir; 3. Upper armature; 4. Housing; 5. Small plunger; 6. Oil chamber; 7. Brake disc; 8. Brake pad; 9. Piston; 10. Caliper body; 11. Brake fluid passage; 12. Lower armature; 13. Pressure relief passage; 14. Moving block; 15. Pressure relief electromagnet; 16. Pressure relief seat; 17. Pressure relief spring; 18. Large plunger; 181. Oil hole; 19. Stop valve needle; 20. Electromagnet; 21. Stop bead; 22. Through hole; 23. Stop spring; 24. Inner core; 241. Angled hole; 25. Large return spring; 26. Pressurization chamber; 27. Small return spring. Detailed Implementation

[0027] Refer to the accompanying drawings in the instruction manual. Figure 1 This electromagnetic drive device needs to be applied to the existing braking system of electric vehicles, which is a disc brake. The braking system structure includes a caliper body 10, shown in the figure as a single piece. The caliper body 10 has an oil chamber 6 for introducing brake fluid. Alternatively, the caliper body 10 can be two pieces, each with a small chamber for introducing brake fluid. The two chambers can be connected by a pipe to form a single oil chamber 6. The caliper body 10 has a brake port communicating with the outside. A brake pad 8 is located on each opposite side of the brake port, movably mounted on the caliper body 10. A brake gap is formed between the two brake pads 8 for the brake disc 7 to extend into. A piston 9 is connected to the back of each brake pad 8. A mounting cavity is located within the caliper body 10 corresponding to the position of the piston 9, with each piston 9 movably mounted within one mounting cavity. The mounting cavity is connected to the oil cavity 6. Under the push of brake fluid, the piston 9 can drive the respective brake pads 8 to move, thereby changing the size of the gap between the two brake pads 8, so that the brake pads 8 abut against the side of the brake disc 7 to achieve braking, or the brake pads 8 disengage from the brake disc 7 to release the braking.

[0028] Figure 1 , 4 As shown in the figure, the structure of this electromagnetic drive device also includes an oil storage tank 2, which is a sealed metal shell structure, and is used to store brake fluid.

[0029] A metal housing 4 is provided between the caliper body 10 and the oil tank 2. The housing 4 and the oil tank 2 are fixedly connected by flanges and bolts. The housing 4 and the caliper body 10 can be welded or fixedly connected by flanges.

[0030] An electromagnetic drive device, including an electromagnet 20, is installed inside the housing 4. An upper space is formed between the oil reservoir 2 and the housing 4, and a lower space is formed between the housing 4 and the caliper body 10. An upper armature 3 is movably disposed in the upper space, and a lower armature 12 is movably disposed in the lower space. The upper armature 3 and lower armature 12 are generally made of iron. When the electromagnet 20 is energized, the magnetic force generated by the electromagnet 20 acts simultaneously on the upper armature 3 and lower armature 12, causing them to move simultaneously towards the electromagnet 20. When the electromagnet 20 is de-energized, the magnetic force disappears, and after the brake disc 7 rotates, the brake disc 7 pushes away the brake pads 8 because the piston 9 is not compressed. A large plunger 18 is connected to the upper armature 3, and a small plunger 5 is connected to the lower armature 12. The diameter of the small plunger 5 is smaller than the diameter of the large plunger 18. The ratio of the outer diameters of the large plunger 18 and the small plunger 5 is between 5 and 6. The outer diameter of the small plunger 5 is smaller than the outer diameter of the piston 9, and the ratio of the outer diameters of the small plunger 5 to the piston 9 is between 18 and 20. One end of the large return spring 25 is fixed relative to the electromagnet 20, and the other end of the large return spring 25 acts on the large plunger 18. One end of the small return spring 27 is fixed relative to the electromagnet 20, and the other end of the small return spring 27 acts on the small plunger 5.

[0031] A brake fluid passage 11 is provided between the oil reservoir 2 and the oil chamber 6. The brake fluid passage 11 extends through multiple structures, connecting the oil reservoir 2 and the oil chamber 6. A large plunger 18 is positioned on the brake fluid passage 11, and a small plunger 5 interacts with the brake fluid in the oil chamber 6. A one-way shut-off valve is provided on the brake fluid passage 11, located between the large plunger 18 and the oil chamber 6, used to allow forward flow and reverse shut-off of the brake fluid. Under the magnetic attraction generated by the electromagnet 20, the large plunger 18 pressurizes the brake fluid in the brake fluid passage 11, causing the brake fluid to flow forward through the one-way shut-off valve. Figure 1 The diagram shows that after the electromagnet 20 is de-energized, the small plunger 5, under the action of the small return spring 27, pushes the brake fluid towards the oil chamber 6. This causes the brake fluid in the oil chamber 6 to push the piston 9, which in turn moves the brake pads 8 against the side of the brake disc 7, achieving braking. At the one-way valve position, the small plunger 5 pushes the brake fluid in the reverse direction, causing the one-way valve to cut off the brake fluid passage 11. At this time, the oil chamber 6 is essentially a closed space. The pressure applied by the small plunger 5 to the brake fluid is directly and equally reflected on the piston 9. Since the outer diameter of the piston 9 is much larger than the outer diameter of the small plunger 5, the piston 9 receives relatively greater pressure, thus pushing the brake pads 8 towards the brake disc 7, achieving braking of the brake disc 7.

[0032] A pressure relief device is also provided between the oil chamber 6 and the oil storage tank 2. The pressure relief device includes a pressure relief passage 13 and a pressure relief valve installed on the pressure relief passage 13. The pressure relief passage 13 is located inside the walls of the caliper body 10 and the housing 4, and connects the oil chamber 6 and the interior of the oil storage tank 2. The pressure relief valve includes a pressure relief electromagnet 15 and a movable block 14 installed in the pressure relief seat 16. The pressure relief seat 16 is fixed to the caliper body 10 on the outside of the housing 4. The pressure relief device is activated after the brake is applied. When the pressure relief electromagnet 15 is energized, it generates a magnetic attraction force that acts on the movable block 14, causing the movable block 14 to disengage from the position where the pressure relief passage 13 is cut off. After the electromagnet 20 is de-energized, the pressure relief spring 17 pressing on the movable block 14 forces the movable block 14 to stabilize in the position where the pressure relief passage 13 is cut off.

[0033] When doing the work, see Figure 4 , 5 When electromagnet 20 is energized, the upper armature 3 and lower armature 12 simultaneously drive the large plunger 18 and the small plunger 5 to move. The large plunger 18 pushes the brake fluid forward through the one-way valve into the oil chamber 6. The small plunger 5 moves, increasing the volume of the oil chamber 6 to facilitate the entry of brake fluid. When electromagnet 20 is de-energized, under the action of the large return spring 25 and the small return spring 27, the large plunger 18 and the small plunger 5 move away from electromagnet 20, causing the small plunger 5 to push the brake fluid in the oil chamber 6 to achieve braking. After braking is complete, the pressure relief valve activates, connecting the pressure relief passage 13 to the oil reservoir 2 and the oil chamber 6. Once the brake fluid pressure in both the oil reservoir 2 and the oil chamber 6 is equal, the pressure relief valve cuts off the pressure relief passage 13.

[0034] The brake fluid passage 11 passes through the large plunger 18 at its axial position. A one-way structure is provided on the large plunger 18, and the brake fluid passage 11 passes through this one-way structure. See also... Figure 5 Under the magnetic attraction generated by electromagnet 20, the large plunger 18 moves towards electromagnet 20, achieving unidirectional structural closure and cutting off the flow of brake fluid, so that the large plunger 18 can pressurize the brake fluid. See also Figure 2 After the electromagnet 20 is de-energized, the large plunger 18 moves away from the electromagnet 20, causing the one-way structure to open, thereby allowing the brake fluid to flow from the reservoir 2 to the oil chamber 6.

[0035] A hollow inner core 24 is provided at the axial position of the electromagnet 20, and the position of the inner core 24 relative to the electromagnet 20 is fixed. The inner core 24 is hollow, and the brake oil passage 11 passes through the inner core 24. The large plunger 18 is of a "convex" shape, and the upper armature 3 is sleeved and fixed on the outer peripheral surface of the small-head end of the large plunger 18. A connecting hole is provided on the bottom wall of the oil storage tank 2, and the small-head end of the large plunger 18 is slidably and liquid-tightly inserted into the connecting hole. An oil hole 181 is provided at the axial position of the large plunger 18, the oil hole 181 penetrates the large plunger 18 in the axial direction of the large plunger 18, and the oil hole 181 serves as a part of the brake oil passage 11. A shut-off valve needle 19 is protruding provided on the top of the inner core 24 at a position corresponding to the oil hole 181. The shut-off valve needle 19 may be integrated with the inner core 24. As shown in the figure, the shut-off valve needle 19 is inserted and fixed in an insertion hole provided on the upper end surface of the inner core 24. After the upper armature 3 pushes the large plunger 18 to move toward the inner core 24 under the action of the magnetic attraction force of the electromagnet 20, the shut-off valve needle 19 will be inserted into the oil hole 181, and the shut-off valve needle 19 will block the flow of brake oil from the oil storage tank 2 to the inner core 24. After the large plunger 18 moves toward the oil storage tank 2 under the action of the large return spring 25, a gap is formed between the outer end of the shut-off valve needle 19 and the oil hole 181, and brake oil will pass through the gap and enter the large-head end of the large plunger 18 from the oil hole 181. The shut-off valve needle 19 and the oil hole 181 constitute the one-way structure, and the opening and closing of the one-way structure is realized along with the axial movement of the large plunger 18.

[0036] A sunken pressure chamber 26 is provided on the upper end surface of the inner core 24, the large-head end of the large plunger 18 is slidably inserted into the pressure chamber 26, liquid sealing is generally formed between the outer peripheral surface of the large-head end of the large plunger 18 and the inner peripheral surface of the pressure chamber 26, and the brake oil passage 11 passes through the pressure chamber 26. The inner core 24 is of an inverted "convex" shape, so that a convex shoulder is formed between the large-head end and the small-head end of the inner core 24, and one end of the small return spring 27 abuts against the convex shoulder. The lower armature 12 is sleeved on the small-head end of the inner core 24 with a gap, and the other end of the small return spring 27 abuts against the lower armature 12. A mounting cavity is provided on the end surface of the large-head end of the large plunger 18, the shut-off valve needle 19 is inserted into the mounting cavity, the large return spring 25 is sleeved on the outer periphery of the shut-off valve needle 19, the pressure chamber 26 is provided in the large-head end of the inner core 24, one end of the large return spring 25 abuts against the bottom surface of the pressure chamber 26, and the other end abuts against the bottom surface of the mounting cavity.

[0037] The oil chamber 6 opens towards the housing 4, and the wall of the housing 4 sealingly covers the opening of the oil chamber 6 towards the caliper body 10. One end of the inner core 24 abuts against the inner surface of the wall of the housing 4. A through hole 22 is provided on the wall, which connects the interior of the inner core 24 and the oil chamber 6. The brake fluid passage 11 passes through the through hole 22. The two ends of the large plunger 18 slide through the oil reservoir 2 and the adjacent walls of the housing 4, respectively. The small plunger 5 is vertically connected to the lower armature 12, extends towards the oil chamber 6, and slides through the wall of the housing 4 towards the caliper body 10. The small plunger 5 is liquid-sealed with the wall, and the outer end of the small plunger 5 extends into the oil chamber 6.

[0038] A recess is provided on the wall of the housing 4 facing the oil cavity 6, protruding towards the oil cavity 6. The small end of the inner core 24 is liquid-sealed against the inner bottom surface of the recess, and the through hole 22 is provided on the bottom surface of the recess. A stop cavity is provided in one end of the inner core 24 facing the oil cavity 6, and several oblique holes 241 penetrating into the stop cavity are provided on the other end face of the inner core 24. The upper end face of the stop cavity is a concave spherical surface, and the outlets of these oblique holes 241 are relatively concentrated on the concave spherical surface. A stop spring 23 and a stop bead 21 are provided in the stop cavity. The diameter of the stop bead 21 is the same as the inner diameter of the concave spherical surface. One end of the stop spring 23 abuts against the bottom surface of the recess, and the other end of the stop spring 23 abuts against the stop bead 21. Under the pressure of the stop spring 23, the stop bead 21 unilaterally covers the outlet of the oblique hole 241, and the stop bead 21 and the stop spring 23 form the one-way stop valve.

[0039] This electromagnetic drive device is used in electric vehicles. The electromagnet 20 housed in the housing 4 and the pressure relief electromagnet 15 housed in the pressure relief seat 16 are both electrically connected to the vehicle's controller 1. The controller 1 is communicatively connected to the brake handle or brake pedal. Taking an electric vehicle as an example, when braking is required, the brake handle rotates, and the controller 1 receives a signal to energize the electromagnet 20. The electromagnet 20 generates a magnetic attraction force, and the upper armature 3 and lower armature 12 overcome the elastic forces of the large return spring 25 and the small return spring 27, respectively, and move towards the electromagnet 20. This causes the large plunger 18 to move towards the inner core 24. Since the gap between the outer end of the stop valve needle 19 and the large plunger 18 is relatively small, the stop valve needle 19 quickly inserts into the oil hole 181, pressurizing the brake fluid in the pressurization chamber 26. After being pressurized, the brake fluid enters the oblique hole 241 of the inner core 24. The brake fluid pushes aside the obstruction of the oblique hole 241 by the stop bead 21 and enters the inner core 24, eventually passing through the through hole 22 and entering the oil chamber 6. Simultaneously, the small plunger 5 moves towards the inner core 24 under the drive of the lower armature 12. The movement of the small plunger 5 increases the volume of the oil chamber 6, which also promotes the entry of brake fluid into the oil chamber 6. In practical applications, when emergency braking is required, as the brake lever deflection angle increases, the current supplied by the controller 1 to the electromagnet 20 decreases, causing the magnetic attraction force generated by the electromagnet 20 to decrease rapidly. The large return spring 25 quickly pushes the large plunger 18 towards the oil reservoir 2, and the small return spring 27 moves towards the oil chamber 6. At this time, the stop bead 21 quickly covers the outlet of the oblique hole 241, and the oil chamber 6 becomes a completely sealed structure. The pressure applied to the brake fluid by the small plunger 5 is quickly transmitted to the piston 9. Under the same pressure, the piston 9 will be subjected to a large thrust, which will quickly drive the brake pad 8 to abut against the brake disc 7 to achieve emergency braking. When slight braking is required, the brake lever deflects at a relatively small angle and quickly returns to its original position. The electromagnet 20, after being energized, quickly de-energizes, thus reducing the amount of brake fluid entering the oil chamber 6. This also reduces the movement of the small plunger 5 and, consequently, the movement of the piston 9, allowing the brake pads 8 to make slight contact with the brake disc 7. The pressure relief passage 13 remains normally closed; that is, under the action of the pressure relief spring 17, the movable block 14 remains in the closed state. After each braking operation, the controller 1 commands the pressure relief electromagnet 15 to activate once. The activation time can be determined based on the deflection angle of the brake lever or the braking time. The magnetic force generated by the pressure relief electromagnet 15 causes the movable block 14 to move, thus opening the closed position. Brake fluid then flows from the oil chamber 6 through the pressure relief passage 13 into the oil reservoir 2. The pressure relief electromagnet 15 has a relatively long start-up time to allow the brake fluid to flow in the pressure relief passage 13 and achieve pressure balance between the brake fluid in the reservoir 2 and the oil chamber 6. The pressure relief time can be determined in actual application or theoretical design stages.After the pressure is released, the pressure relief electromagnet 15 will be de-energized, thus cutting off the pressure relief passage 13. When the electric vehicle is stationary or in use and braking is not required, the brake fluid will automatically adjust its flow throughout the braking system. The brake fluid will enter the pressure chamber 26 through the gap between the large plunger 18 and the shut-off valve needle 19, so that it can be pressurized by the large plunger 18 when the brake is activated next time.

Claims

1. An electromagnetic drive device for electric vehicle electronic brakes, comprising an electromagnet disposed within the caliper body and a communicating brake fluid passage and fluid chamber, characterized in that, An upper armature and a lower armature are respectively movably arranged on opposite sides of the electromagnet within the caliper body, a large plunger is connected to the upper armature, a small plunger is connected to the lower armature, and the diameter of the small plunger is smaller than that of the large plunger and the piston; one end of the large return spring is fixed relative to the position of the electromagnet, and the other end of the large return spring acts on the large plunger; one end of the small return spring is fixed relative to the position of the electromagnet, and the other end of the small return spring acts on the small plunger; the large plunger is arranged on the brake oil passage, and the small plunger is configured to act on the brake oil in the oil cavity; The one-way stop valve is arranged on the brake oil passage and located between the large plunger and the oil cavity, and is configured to conduct brake oil in the forward direction and cut off brake oil in the reverse direction; The invention further comprises a pressure relief passage arranged in the caliper body and a pressure relief valve arranged on the pressure relief passage, wherein the pressure relief passage is connected with the brake oil passage.

2. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 1, characterized in that, An oil storage tank is arranged on the caliper body, the brake oil passage passes through the large plunger, a one-way structure is arranged on the large plunger, the brake oil passage passes through the one-way structure, when the large plunger moves toward the electromagnet, the one-way structure is closed to cut off the flow of brake oil; when the large plunger moves away from the electromagnet, the one-way structure is opened to conduct the flow of brake oil from the oil storage tank to the oil cavity.

3. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 2, characterized in that, A hollow inner core is arranged on the electromagnet, the brake oil passage passes through the inner core, and the one-way structure is arranged between the inner core and the large plunger.

4. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 3, characterized in that, A connection hole is arranged on the bottom wall of the oil storage tank, the large plunger is slidably and liquid-tightly inserted into the connection hole; an oil hole is arranged in the large plunger, and the oil hole serves as a part of the brake oil passage.

5. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 4, characterized in that, A stop valve pin is protruding arranged at a position corresponding to the oil hole on the top of the inner core, the stop valve pin is configured to be inserted into the oil hole or disengaged from the oil hole, and the stop valve pin and the oil hole form the one-way structure.

6. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 3, 4 or 5, characterized in that, A pressurizing cavity is arranged on the upper end face of the inner core, the lower end of the large plunger is slidably inserted into the pressurizing cavity, and the brake oil passage passes through the pressurizing cavity.

7. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 6, characterized in that, The inner core is in an inverted "convex" shape, so that a convex shoulder is formed between the large end and the small end of the inner core, one end of the small return spring abuts against the convex shoulder; the pressurizing cavity is arranged in the large end of the inner core, and one end of the large return spring abuts against the bottom surface of the pressurizing cavity.

8. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 7, characterized in that, The caliper body and the oil storage tank are respectively fixedly connected to opposite side surfaces of the housing, an upper space for the upper armature to move is formed between the oil storage tank and the housing, and a lower space for the lower armature to move is formed between the housing and the caliper body; two ends of the large plunger respectively slidably penetrate through the adjacent wall bodies of the oil storage tank and the housing, and the small plunger slidably penetrates through the wall body of the housing facing the caliper body.

9. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 8, characterized in that, The oil cavity opens toward the housing, the wall body of the housing facing the caliper body hermetically covers the opening of the oil cavity, one end of the inner core abuts against the inner surface of the wall body of the housing, a through hole is arranged on the wall body, the through hole communicates the inside of the inner core with the oil cavity, and the brake oil passage passes through the through hole; the small plunger passes through the wall body.

10. The electric vehicle electronically controlled brake electromagnetic drive device according to claim 3, 4 or 5, characterized in that, A stop cavity is arranged in one end of the inner core facing the oil cavity, a plurality of inclined holes penetrating to the stop cavity are arranged on the other end face of the inner core, a stop spring and a stop ball are arranged in the stop cavity, under the pressing of the stop spring, the stop ball is configured to cover the outlets of the inclined holes, and the stop ball and the stop spring form the one-way stop valve.

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