A high-pressure brake assembly for distributed braking, design method and use thereof

Abstract

The present invention discloses a high-pressure brake assembly, design method and use for distributed braking, which belongs to the field of automobile braking technology, and includes a motor drive unit, a mechanical power-assisted self-locking unit and a piston-type pressure output unit that are detachably connected in sequence, wherein the motor drive unit includes a first housing and a motor body fixed inside the first housing; the mechanical power-assisted self-locking unit includes a planetary gear pair and a double-screw nut pair connected to the output end of the motor drive unit, and the double-screw nut pair includes a large nut screw motion pair connected to the output end of the planetary gear pair and a small nut screw motion pair connected to the output end of the motor drive unit, and the lead of the large nut screw motion pair is greater than the lead of the small nut screw motion pair. The high-pressure brake assembly, design method and use for distributed braking are adopted, and braking is performed by multiple motors in conjunction with the mechanical power-assisted self-locking unit, which has a simple control algorithm and can realize a power-off mechanical self-locking function, thereby meeting the requirements of long-term parking.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile braking, and in particular to a high-pressure braking assembly for distributed braking, a design method and a use thereof. Background Art

[0002] In recent years, ESC HCU active boost braking, electro-hydraulic servo braking (EHB) and integrated electro-hydraulic braking (i.e. One-Box braking system, which can integrate ESC's HCU into electro-hydraulic servo braking) superimposed on vacuum power assist have appeared one after another. In particular, the electro-hydraulic servo braking and integrated electro-hydraulic braking that have appeared in recent years, the former, alone or in conjunction with ESC's HCU, can achieve power-assisted braking, autonomous braking and wire-controlled braking that supports brake energy recovery; the latter alone has all of the above functions.

[0003] The above brake systems all use electromagnetic valves to adjust the wheel cylinder pressure to meet the pressure control requirements of ABS / ASR / ESC. Therefore, the existing electro-hydraulic brake devices still have the following deficiencies:

[0004] 1. The ESC hydraulic unit has problems such as the solenoid valve is not suitable for long-term continuous operation, the working life of the plunger pump is difficult to meet, and the plunger pump motor has high noise;

[0005] 2. The sealing of the high-pressure accumulator of EHB is difficult, and there are safety hazards due to the high pressure. In addition, the entire system needs to work frequently to maintain sufficient standing pressure, thus consuming more energy;

[0006] 3. Some electric power assist devices are not self-decoupled and require the cooperation of the ESC hydraulic unit to achieve brake pedal travel simulation and wire control braking, which increases the complexity of the system;

[0007] 4. The internal parts of the solenoid valve are complex, and multiple solenoid valves are required to have very high consistency, which requires extremely high processing accuracy, raising the threshold of the entire wire control brake.

[0008] In summary, the existing brake pressure regulation methods of electro-hydraulic brake devices all belong to flow regulation, and their pressure response dynamic characteristics are poor. Summary of the invention

[0009] The purpose of the present invention is to provide a high-pressure brake assembly, a design method and a use for distributed braking to solve the above-mentioned technical problems.

[0010] To achieve the above-mentioned object, the present invention provides a high-pressure brake assembly for distributed braking, comprising a motor drive unit, a mechanical power-assisted self-locking unit and a piston-type pressure output unit which are detachably connected in sequence, wherein the motor drive unit comprises a first housing and a motor body fixed inside the first housing;

[0011] The mechanical power-assisted self-locking unit includes a planetary gear pair and a double screw-nut pair connected to the output end of the motor drive unit. The double screw-nut pair includes a large nut screw motion pair connected to the output end of the planetary gear pair and a small nut screw motion pair connected to the output end of the motor drive unit. The lead of the large nut screw motion pair is greater than the lead of the small nut screw motion pair.

[0012] Preferably, the planetary gear pair comprises an inner gear ring fixed inside the first housing, a sun gear arranged concentrically with the inner gear ring, and a plurality of planetary gears respectively meshing with the sun gear and the inner gear ring, the rotating shafts of the plurality of planetary gears are all rotatably connected with a retainer, and the retainer is arranged on a side of the planetary gear away from the motor body;

[0013] The large nut screw motion pair includes a large screw integrally connected to one end of the retaining frame away from the motor body and a large nut threadedly connected to the outer circumference of the large screw, and the large screw is a multi-start screw structure;

[0014] The small nut-screw motion pair includes a small screw fixedly connected to the rotor output shaft of the motor body, the small screw passes through the sun gear and is threadedly connected to the small nut, and the small screw is a single-start screw structure;

[0015] One end of the large nut away from the motor body and one end of the small nut away from the motor body are both aligned with the power input end of the piston type pressure output unit;

[0016] The small nut and the large nut are both axially slidably connected with the fixed disk via a stop pin.

[0017] Preferably, the piston-type pressure output unit comprises a thrust plate with one side aligned with the large nut and the small nut respectively, a piston fixedly connected to the other side of the thrust plate, and a piston cylinder, the piston is slidably arranged inside the piston cylinder, and a return spring is arranged between the piston and the inner wall of the piston cylinder;

[0018] The large nut and the small nut are aligned with the thrust plate through the push rod, and a Y-shaped sealing ring and a limit plate are arranged in sequence between the push rod of the large nut and the thrust plate;

[0019] The piston cylinder is provided with an oil inlet and an oil outlet respectively, and the oil inlet and the oil outlet are respectively arranged at two ends of the piston.

[0020] Preferably, the piston-type pressure output unit is integrated on the second housing, and the second housing is detachably connected to the first housing via a countersunk screw;

[0021] A fixing plate is fixed inside the second shell.

[0022] Preferably, the motor body is a hollow shaft motor, and the rotor output shaft of the hollow shaft motor is fixedly connected to the small lead screw via a locking nut.

[0023] The design method of a high-pressure brake assembly for distributed braking includes the design of the relationship between the friction angle and the equivalent friction angle of the large nut-screw motion pair and the small nut-screw motion pair and the piston stroke design;

[0024] Among them, the design method of the relationship between the friction angle and the equivalent friction angle of the large nut screw motion pair and the small nut screw motion pair is as follows:

[0025] The friction angle of the large nut-screw motion pair is set to λ1, and the equivalent friction angle is ρv 1 ; and set the friction angle of the small nut screw motion pair to λ2, and the equivalent friction angle to ρ v2 ; Then λ2>ρ v2 >ρv 1 >λ1;

[0026] The piston stroke design method is as follows:

[0027] When the piston stroke is set to Sm, there is an initial position stroke difference ΔS=Sm / v1×v2-Sm>0 between the large nut screw motion pair and the small nut screw motion pair, so that when the piston stroke is less than Sm, the large nut screw motion pair is used to assist braking; when the piston stroke is greater than Sm, the small nut screw motion pair is used to achieve self-locking parking.

[0028] Preferably, the calculation formula of friction angle and equivalent friction angle is as follows:

[0029] λ1=arctan(i1p1 / (πD1) (1);

[0030] ρ v 1 = arctan(f1 / cos(β1) (2);

[0031] λ2=arctan(i2p2 / (πD2) (3);

[0032] ρ v 2 = arctan(f2 / cos(β2) (4);

[0033] Wherein, i1 and i2 are the number of heads of the large screw and the small screw respectively, p1 and p2 are the leads of the large screw and the small screw respectively, D1 and D2 are the middle diameters of the large nut screw motion pair and the small nut screw motion pair respectively, f1 and f2 are the friction coefficients of the large nut screw motion pair and the small nut screw motion pair respectively, β1 and β2 are the tooth side angles of the large nut screw motion pair and the small nut screw motion pair respectively.

[0034] Preferably, the piston stroke Sm design formula is as follows:

[0035] n2=1+Zb / Za (5);

[0036] v2=i2p2 / n2 (6);

[0037] v1=p2 (7);

[0038] Where n2 is the speed ratio of the planetary gear pair; Zb is the number of teeth on the inner ring; Za is the number of teeth on the sun gear; v1 is the moving speed of the large nut-screw motion pair, in mm / r; v1 is the moving speed of the small nut-screw motion pair, in mm / r.

[0039] An application of a high-pressure brake assembly for distributed braking on four wheel cylinders of a vehicle.

[0040] The four high-pressure brake assemblies for distributed braking are respectively used on four wheel cylinders of a vehicle.

[0041] Therefore, the present invention adopts the above-mentioned high-pressure brake assembly, design method and use for distributed braking, which has the following beneficial effects:

[0042] 1. Avoid electromagnetic control and achieve braking through multi-motor control, making the control algorithm simpler;

[0043] 2. Modular design: The whole unit is split into motor drive unit, mechanical power-assisted self-locking unit and pressure output unit. Each part can be replaced independently based on product requirements, which is applicable to a wide range of scenarios;

[0044] 3. Through assembly and combination, it can not only meet the braking needs of unmanned logistics vehicles, but also can be used in combination to meet the braking needs of large-tonnage ordinary passenger vehicles. Even just by adjusting the motor power, it can meet the braking needs of large-tonnage commercial vehicles.

[0045] 4. In addition to meeting the requirements of the high-voltage braking unit, a power-off mechanical self-locking parking device can be implemented to meet the requirements of long-term parking without worrying about current overheating, which is safer.

[0046] 5. Design the calculation relationship between the friction angle λ and the equivalent friction angle ρv of the two screw nut pairs and the calculation method of the master cylinder stroke, making the final result more scientific and reliable.

[0047] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a cross-sectional view of a high-pressure brake assembly for distributed braking of the present invention;

[0049] Figure 2 It is a structural schematic diagram of a mechanical power-assisted self-locking unit of a high-pressure brake assembly for distributed braking according to the present invention;

[0050] Figure 3 It is a structural schematic diagram of a retainer of a high-pressure brake assembly for distributed braking according to the present invention;

[0051] Figure 4 The figure is an appearance diagram of a high-pressure brake assembly for distributed braking according to the present invention.

[0052] Reference numerals

[0053] 1. Motor drive unit; 11. Motor body; 12. Rotor output shaft; 2. Mechanical power-assisted self-locking unit; 21. Sun gear; 22. Planetary gear; 23. Internal gear ring; 24. Small lead screw; 25. Cage; 26. Large lead screw; 27. Large nut; 28. Small nut; 29. ​​Push rod; 3. Piston pressure output unit; 31. Thrust plate; 32. Piston; 33. Piston cylinder; 34. Reset spring; 35. Oil inlet; 36. Oil outlet; 4. Second housing; 5. Fixed plate; 6. First housing; 7. Mounting seat. DETAILED DESCRIPTION

[0054] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0056] Since the dynamic characteristics of pressure response of circulation regulation are not as good as those of variable capacity regulation, four-wheel brake pressure variable capacity regulation is adopted.

[0057] Based on the above analysis, the present invention is designed as follows: Figure 1-Figure 4As shown, a high-pressure brake assembly for distributed braking includes a motor drive unit 1, a mechanical power-assisted self-locking unit 2 (used to increase the thrust of the piston 32 of the piston pressure output unit 3 by increasing the output torque of the motor drive unit 1) and a piston pressure output unit 3, which are detachably connected in sequence. The motor drive unit 1 includes a first shell 6 and a motor body 11 fixed inside the first shell 6; wherein the mechanical power-assisted self-locking unit 2 includes a planetary gear pair and a double-screw nut pair connected to the output end of the motor drive unit 1, and the double-screw nut pair includes a large nut screw motion pair connected to the output end of the planetary gear pair and a small nut screw motion pair connected to the output end of the motor drive unit 1, and the lead of the large nut screw motion pair is greater than the lead of the small nut screw motion pair.

[0058] Specifically, the planetary gear pair includes an inner gear ring 23 fixed inside the first housing 6, a sun gear 21 arranged concentrically with the inner gear ring 23, and a plurality of planetary gears 22 respectively meshing with the sun gear 21 and the inner gear ring 23. The rotating shafts of the plurality of planetary gears 22 are rotatably connected with a retainer 25, and the retainer 25 is arranged on the side of the planetary gear 22 away from the motor body 11; the large nut and lead screw motion pair includes a large lead screw 26 integrally connected to one end of the retainer 25 away from the motor body 11, and a large nut 27 threadedly connected to the outer circumferential side of the large lead screw 26. The lever 26 is a multi-start screw structure; the small nut-screw motion pair includes a small screw 24 fixedly connected to the rotor output shaft 12 of the motor body 11, and the small screw 24 is threadedly connected to the small nut 28 after passing through the sun gear 21, and the small screw 24 is a single-start screw structure; the end of the large nut 27 away from the motor body 11 and the end of the small nut 28 away from the motor body 11 are both aligned with the power input end of the piston-type pressure output unit 3; the small nut 28 and the large nut 27 are both axially slidably connected to the fixed plate 5 via a stop pin, which is used to limit the rotation of the large nut 27 and the small nut 28.

[0059] The piston-type pressure output unit 3 includes a thrust plate 31, one side of which is aligned with the large nut 27 and the small nut 28 respectively, a piston 32 fixedly connected to the other side of the thrust plate 31, and a piston cylinder 33. The piston 32 is slidably arranged inside the piston cylinder 33, and a return spring 34 is arranged between the piston 32 and the inner wall of the piston cylinder 33; the large nut 27 and the small nut 28 are aligned with the thrust plate 31 through a push rod 29, and a Y-shaped sealing ring and a limit plate are also arranged in sequence between the push rod 29 of the large nut 27 and the thrust plate 31, which are used to limit the initial position of the large nut 27, so that there is an initial stroke difference between the large nut 27 and the small nut 28, so that the large nut 27 first contacts the thrust plate 31 for power-assisted braking until the set stroke of the piston 32 is reached, and then the nut is used for self-locking; the piston cylinder 33 is respectively provided with an oil inlet 35 and an oil outlet 36, and the oil inlet 35 and the oil outlet 36 are respectively arranged at both ends of the piston 32.

[0060] The piston-type pressure output unit 3 is integrated on the second housing 4 , and the second housing 4 is detachably connected to the first housing 6 via a countersunk screw; a fixing plate 5 is fixed inside the second housing 4 .

[0061] In this embodiment, mounting seats 7 are fixed on the first shell 6 and the second shell 4 for mounting them on the vehicle body.

[0062] The motor body 11 is a hollow shaft motor, and the rotor output shaft 12 of the hollow shaft motor is fixedly connected to the small lead screw 24 via a locking nut. The hollow shaft motor can reduce the size of the device.

[0063] Working principle: After the motor body 11 is energized, it drives the rotor output shaft 12 to rotate, and then drives the small screw 24 to rotate. The small screw 24 drives the sun gear 21 to rotate, drives the planetary gear 22 to rotate around the sun gear 21, and then drives the retaining frame 25 to rotate. The retaining frame 25 drives the large screw 26 to rotate, thereby driving the large nut 27 to move axially along the large screw 26 under the action of the multi-start thread. At the same time, the small screw 24 rotates, and drives the small nut 28 to move axially along the small screw 24 under the action of the single-start thread. In this process, the large nut 27 is used to push the thrust plate 31, and then push the piston 32 to extend, compressing the hydraulic oil entering the piston cylinder 33. The compressed hydraulic oil enters the wheel cylinder through the oil outlet 36 to achieve power-assisted braking. Until the stroke of the piston 32 reaches the designed stroke, the small nut 28 pushes the thrust plate 31 (the thrust plate 31 is out of contact with the large nut 27), and the power-off self-locking is achieved.

[0064] The design method of a high-pressure brake assembly for distributed braking includes the design of the relationship between the friction angle and the equivalent friction angle of the large nut-screw motion pair and the small nut-screw motion pair and the stroke design of the piston 32;

[0065] Among them, the design method of the relationship between the friction angle and the equivalent friction angle of the large nut screw motion pair and the small nut screw motion pair is as follows:

[0066] The friction angle of the large nut-screw motion pair is set to λ1, and the equivalent friction angle is set to ρ v1 ; and set the friction angle of the small nut screw motion pair to λ2, and the equivalent friction angle to ρ v2 ; then λ2>ρ v2 >ρ v1 >λ1;

[0067] The calculation formulas for friction angle and equivalent friction angle are as follows:

[0068] λ1=arctan(i1p1 / (πD1) (1);

[0069] ρ v 1 = arctan(f1 / cos(β1) (2);

[0070] λ2=arctan(i2p2 / (πD2) (3);

[0071] ρ v 2 = arctan(f2 / cos(β2) (4);

[0072] Wherein, i1 and i2 are the number of heads of the large screw 26 and the small screw 24 respectively, p1 and p2 are the leads of the large screw 26 and the small screw 24 respectively, D1 and D2 are the middle diameters of the large nut screw motion pair and the small nut screw motion pair respectively, f1 and f2 are the friction coefficients of the large nut screw motion pair and the small nut screw motion pair respectively, β1 and β2 are the tooth side angles of the large nut screw motion pair and the small nut screw motion pair respectively.

[0073] The stroke design method of piston 32 is as follows:

[0074] When the stroke of the piston 32 is set to Sm, there is an initial position stroke difference ΔS=Sm / v1×v2-Sm>0 between the large nut screw motion pair and the small nut screw motion pair, so that when the stroke of the piston 32 is less than Sm, the large nut screw motion pair is used to assist braking; when the stroke of the piston 32 is greater than Sm, the small nut screw motion pair is used to achieve self-locking parking.

[0075] The design formula for piston 32 stroke Sm is as follows:

[0076] n2=1+Zb / Za (5);

[0077] v2=i2p2 / n2 (6);

[0078] v1=p2 (7);

[0079] Where n2 is the speed ratio of the planetary gear pair; Zb is the number of teeth of the inner ring gear 23; Za is the number of teeth of the sun gear 21; v1 is the moving speed of the large nut-screw motion pair, in mm / r; v1 is the moving speed of the small nut-screw motion pair, in mm / r.

[0080] Based on the tonnage and brake fluid volume requirements of different vehicle models, a high-pressure brake assembly for distributed braking is applied to four wheel cylinders of a vehicle.

[0081] Based on the tonnage and brake fluid volume requirements of different vehicle models, four high-pressure brake assemblies for distributed braking are respectively applied to four wheel cylinders of the vehicle.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-pressure brake assembly for distributed braking, characterized in that: It includes a motor drive unit, a mechanical power-assisted self-locking unit and a piston-type pressure output unit which are detachably connected in sequence, and the motor drive unit includes a first shell and a motor body fixed inside the first shell; The mechanical power-assisted self-locking unit includes a planetary gear pair and a double lead screw nut pair connected to the output end of the motor drive unit, the double lead screw nut pair includes a large nut lead screw motion pair connected to the output end of the planetary gear pair and a small nut lead screw motion pair connected to the output end of the motor drive unit, the lead of the large nut lead screw motion pair is greater than the lead of the small nut lead screw motion pair; The planetary gear pair includes an inner gear ring fixed inside the first housing, a sun gear arranged concentrically with the inner gear ring, and a plurality of planetary gears respectively meshing with the sun gear and the inner gear ring, wherein the rotating shafts of the plurality of planetary gears are rotatably connected with a retainer, and the retainer is arranged on a side of the planetary gear away from the motor body; The large nut screw motion pair includes a large screw integrally connected to one end of the retaining frame away from the motor body and a large nut threadedly connected to the outer circumference of the large screw, and the large screw is a multi-start screw structure; The small nut-screw motion pair includes a small screw fixedly connected to the rotor output shaft of the motor body, the small screw passes through the sun gear and is threadedly connected to the small nut, and the small screw is a single-start screw structure; One end of the large nut away from the motor body and one end of the small nut away from the motor body are both aligned with the power input end of the piston type pressure output unit; The small nut and the large nut are both axially slidably connected to the fixed disk via a stop pin; The piston type pressure output unit comprises a thrust plate with one side aligned with the large nut and the small nut respectively, a piston fixedly connected to the other side of the thrust plate, and a piston cylinder, wherein the piston is slidably arranged inside the piston cylinder, and a return spring is arranged between the piston and the inner wall of the piston cylinder; The large nut and the small nut are aligned with the thrust plate through the push rod, and a Y-shaped sealing ring and a limit plate are arranged in sequence between the push rod of the large nut and the thrust plate; The piston cylinder is provided with an oil inlet and an oil outlet respectively, and the oil inlet and the oil outlet are respectively arranged at two ends of the piston.

2. A high-pressure brake assembly for distributed braking according to claim 1, characterized in that: The piston-type pressure output unit is integrated on the second housing, and the second housing is detachably connected to the first housing via a countersunk screw; A fixing plate is fixed inside the second shell.

3. A high-pressure brake assembly for distributed braking according to claim 1, characterized in that: The motor body is a hollow shaft motor, and the rotor output shaft of the hollow shaft motor is fixedly connected with a small lead screw via a locking nut.

4. A design method for a high-pressure brake assembly for distributed braking as described in any one of claims 1 to 3, characterized in that: Including the design of the relationship between the friction angle and the equivalent friction angle of the large nut screw motion pair and the small nut screw motion pair, as well as the piston stroke design; Among them, the design method of the relationship between the friction angle and the equivalent friction angle of the large nut screw motion pair and the small nut screw motion pair is as follows: The friction angle of the large nut-screw motion pair is set to , the equivalent friction angle is ; and set the friction angle of the small nut screw motion pair to , the equivalent friction angle is ; then there is ; The piston stroke design method is as follows: Set the piston stroke to , there is an initial position travel difference between the large nut screw motion pair and the small nut screw motion pair , when the piston stroke is less than When the piston stroke is greater than When the vehicle is in a locked state, a small nut and screw motion pair is used to achieve self-locking parking.

5. The design method of a high-pressure brake assembly for distributed braking according to claim 4 is characterized in that: The calculation formulas for friction angle and equivalent friction angle are as follows: （1）； （2）； （3）； （4）； In the formula, , are the number of heads of the large and small screws, respectively. , are the leads of the large and small lead screws, , are the middle diameters of the large nut-screw motion pair and the small nut-screw motion pair, , are the friction coefficients of the large nut-screw motion pair and the small nut-screw motion pair, , They are the tooth side angles of the large nut-screw motion pair and the small nut-screw motion pair respectively.

6. The design method of a high-pressure brake assembly for distributed braking according to claim 4 is characterized in that: Piston stroke The design formula is as follows: （5）； （6）； （7）； In the formula, is the speed ratio of the planetary gear pair; is the number of teeth on the inner ring gear; is the number of sun gear teeth; is the moving speed of the large nut-screw motion pair, in mm / r; It is the movement speed of the small nut-screw motion pair, and the unit is mm / r.

7. Application of a high-pressure brake assembly for distributed braking as described in any one of claims 1 to 3 on four wheel cylinders of a vehicle.

8. Application of four high-pressure brake assemblies for distributed braking as described in any one of claims 1 to 3 on four wheel cylinders of a vehicle respectively.

Images