CN113442886A

CN113442886A - Brake master cylinder, hydraulic brake system and vehicle

Info

Publication number: CN113442886A
Application number: CN202010225217.8A
Authority: CN
Inventors: 程佳; 朱晓军; 李俊峰; 郭海
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-03-26
Filing date: 2020-03-26
Publication date: 2021-09-28
Anticipated expiration: 2040-03-26
Also published as: CN113442886B

Abstract

The invention relates to the technical field of hydraulic braking, and discloses a braking master cylinder, a hydraulic braking system and a vehicle. The brake master cylinder comprises a master cylinder body and a piston, wherein a cylinder cavity is formed in the master cylinder body, and the piston can be arranged in the cylinder cavity in a sealing sliding mode and divides the cylinder cavity into a master cylinder front cavity and a master cylinder rear cavity; the main cylinder rear cavity is provided with an oil inlet and an oil outlet; the main cylinder front cavity is provided with a liquid supplementing port and a pressurizing oil port; the piston can close the pressurizing oil port in an unbraked state, and the piston can move toward the rear chamber of the master cylinder to open the pressurizing oil port when receiving driving force from the brake pedal. Because the piston can seal the pressurizing oil port when in an unbraked state, pressurized hydraulic oil can be prevented from directly entering the front cavity of the main cylinder, and the occurrence of error braking is avoided. During braking, the piston moves towards the rear cavity of the main cylinder under the driving of the brake pedal to open the pressurizing oil port, and pressurized hydraulic oil can enter the front cavity of the main cylinder through the pressurizing oil port to provide braking assistance for the piston.

Description

Brake master cylinder, hydraulic brake system and vehicle

Technical Field

The invention relates to the technical field of hydraulic braking, in particular to a braking main cylinder, a hydraulic braking system and a vehicle.

Background

The prior art provides an electronic control hydraulic braking system, including brake master cylinder and energy storage ware, brake master cylinder includes helping hand room and helping hand piston, and the helping hand room has a helping hand hydraulic fluid port that opens always, and the energy storage ware stores the pressure of certain intensity to supply pressure to the helping hand room, be provided with the control valve in the flow path between the helping hand hydraulic fluid port of energy storage ware and helping hand room, the control valve is controlled the oil that supplies with from the energy storage ware to the helping hand room.

The brake master cylinder has certain defects, when the brake master cylinder is not used, if the control valve between the energy accumulator and the boosting oil port is abnormally opened, the pressure in the energy accumulator directly enters the boosting chamber, the wrong brake action is caused, and potential safety hazards exist.

Disclosure of Invention

The invention aims to provide a brake master cylinder which can provide boosting brake during braking, can avoid error braking during non-braking and improves safety performance.

In order to achieve the above object, the present invention provides a brake master cylinder including:

the cylinder comprises a main cylinder body, a cylinder cavity and a cylinder cover, wherein a cylinder cavity is formed in the main cylinder body;

a piston sealingly slidably disposed within the cylinder chamber and dividing the cylinder chamber into a master cylinder front chamber and a master cylinder rear chamber;

the main cylinder rear cavity is provided with an oil inlet and an oil outlet; the master cylinder front cavity is provided with a liquid supplementing port and a pressurizing oil port;

the piston may close the pressurizing oil port in an unbraked state, and the piston may move toward the master cylinder rear chamber to open the pressurizing oil port when receiving a driving force from a brake pedal.

Through the technical scheme, the piston can seal the pressurizing oil port when in the non-braking state, so that pressurized hydraulic oil can be prevented from directly entering the front cavity of the main cylinder, and the occurrence of error braking is avoided. And during braking, the piston moves towards the rear cavity of the main cylinder under the driving of the brake pedal to open the pressurizing oil port, at the moment, pressurized hydraulic oil can enter the front cavity of the main cylinder through the pressurizing oil port to provide braking assistance for the piston, and at the moment, an oil path at the liquid supplementing port of the front cavity of the main cylinder is cut off.

For example, after the brake master cylinder is applied to a hydraulic brake system, during normal braking, hydraulic pressure in the front cavity of the master cylinder is connected with the liquid storage pot through the liquid supplementing port, so that in the process of stepping on a brake pedal and releasing the brake pedal, the pressure in the front cavity of the master cylinder cannot change suddenly, and the feeling of the brake pedal and the braking force cannot be influenced additionally. When the boosting oil port abnormally leads high-pressure oil to enter the boosting oil port, the high-pressure oil at the boosting oil port cannot enter the front cavity of the main cylinder due to the sealing effect of the piston, active forced braking cannot be caused, and the high-pressure oil can enter the front cavity of the main cylinder only when the brake pedal is stepped on by a foot to push the piston to cause the sealing of the boosting oil port to be opened. For example, when the motor fails or the brake system is powered off and enters the mechanical standby brake mode, and a driver steps on the brake pedal, the piston is pushed to move, the pressure boosting oil port on the front cavity of the main cylinder is opened, and hydraulic oil in the hydraulic energy accumulator enters the front cavity of the main cylinder through the pressure boosting oil port, so that when the brake system is powered off and the motor fails, brake assistance is provided for the step-on brake pedal, the requirement of output brake force on input pedal force is reduced, and the brake reliability and the driving safety of the hydraulic brake system in the mechanical standby brake mode are ensured.

Further, the piston includes a large diameter section and a small diameter section for connection with a brake pedal, the large diameter section and an inner peripheral surface of the cylinder chamber are sealingly slidably fitted, and the small diameter section is located in the master cylinder front chamber and forms an annular space with the inner peripheral surface of the master cylinder front chamber.

Furthermore, a first sealing leather cup and a second sealing leather cup which are axially arranged at intervals are arranged between the outer peripheral surface of the large-diameter section and the inner peripheral surface of the cylinder cavity, wherein the first sealing leather cup and the second sealing leather cup are positioned on two axial sides of the pressurizing oil port in an unbraked state.

Still further, the first sealing cup and the second sealing cup respectively comprise an outer lip and an inner lip which are arranged at intervals in the radial direction, an interval opening is formed between the outer lip and the inner lip, and the interval opening faces the pressurizing oil port.

Furthermore, a piston ring groove close to the small-diameter section is formed in the outer peripheral surface of the large-diameter section, a side wall of the piston ring groove, facing the small-diameter section, serves as a groove shoulder, one side of the groove shoulder serves as the small-diameter section, the other side of the groove shoulder serves as the piston ring groove, and the first sealing leather cup is arranged in the piston ring groove.

Further, a third sealing cup axially spaced from the second sealing cup is disposed between an outer circumferential surface of an end portion of the large-diameter section facing the rear chamber of the master cylinder and an inner circumferential surface of the cylinder chamber.

Still further, the third seal cup includes radially spaced apart outer and inner lips, respectively, forming a spaced opening therebetween facing the master cylinder rear chamber.

Furthermore, a first annular groove, a second annular groove and a third annular groove which are axially spaced are formed on the inner circumferential surface of the cylinder cavity, and the first annular groove and the second annular groove are positioned on two axial sides of the pressurizing oil port; the first sealing leather cup is arranged in the first annular groove, the second sealing leather cup is arranged in the second annular groove, and the third sealing leather cup is arranged in the third annular groove.

In addition, the master cylinder further comprises a spring; axial holes are respectively formed on two axial end faces of the piston; a push rod axially penetrates out of the front cavity of the main cylinder and is used for connecting a brake pedal is arranged in one axial hole; one end of the spring is accommodated and positioned in the other axial hole, and the other end of the spring is connected to the main cylinder end cover of the main cylinder body.

Furthermore, the present application provides a hydraulic brake system provided with the master cylinder as described in any of the above. As described above, the braking performance and safety performance of the hydraulic braking system are effectively improved.

Drawings

FIG. 1 is a schematic cross-sectional view of a brake master cylinder according to an embodiment of the present invention, showing a piston sealing a pressurizing oil port when not braking;

FIG. 2 is a schematic perspective view of the piston of FIG. 1;

FIG. 3 is a schematic cross-sectional view of another master cylinder of the present invention, showing the piston sealing the pressurizing oil port when not braking;

FIG. 4 is a schematic perspective view of the piston of FIG. 3;

FIG. 5 is a schematic illustration of a hydraulic brake system according to an embodiment of the present invention;

FIG. 6 is a schematic perspective view of a sealing cup according to the present invention;

FIG. 7 is a schematic cross-sectional view of FIG. 6;

fig. 8 is an enlarged view of a portion of the structure of fig. 7.

Description of the reference numerals

1-main cylinder body, 2-piston, 3-main cylinder front chamber, 4-main cylinder rear chamber, 5-push rod, 6-fluid infusion port, 7-pressure boosting oil port, 8-large diameter section, 9-small diameter section, 10-annular interval, 11-first sealing leather cup, 12-second sealing leather cup, 13-third sealing leather cup, 14-groove shoulder, 15-spring, 16-main cylinder end cover, 17-oil outlet, 18-piston annular groove, 19-push rod sealing ring, 20-brake pedal, 21-main cylinder pressure boosting control valve, 22-brake pump, 23-hydraulic accumulator, 24-accumulator oil supply one-way valve, 25-hydraulic accumulator pressure sensor, 26-oil return control valve, 27-pressure medium storage container, 28-solenoid valve, 29-annular body, 30-axial channel, 31-outer lip, 32-inner lip, 33-spacing space, 34-end face, 35-buffer recess, 36-radial outer side, 37-radial inner side, 38-primary seal lip, 39-secondary seal lip, 40-cavity, 41-axial flat face section, 42-first axial slope section, 43-second axial slope section, 44-radial flat face section, 45-outer peripheral face recess, 46-outer peripheral face axial flat face section.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Referring to the structures shown in fig. 1, 2, 3 and 4, the brake master cylinder provided by the invention comprises a master cylinder body 1 and a piston 2, wherein a cylinder cavity is formed in the master cylinder body 1, the piston 2 is arranged in the cylinder cavity in a sealing and sliding manner and divides the cylinder cavity into a master cylinder front chamber 3 and a master cylinder rear chamber 4, the master cylinder rear chamber 4 is provided with an oil inlet and an oil outlet for connecting with a brake oil path, the master cylinder front chamber 3 is provided with a fluid supplementing port 6 and a pressurizing oil port 7, the piston 2 can seal the pressurizing oil port 7 in an unbraked state, and the piston 2 can move towards the master cylinder rear chamber 4 to open the pressurizing oil port 7 when being subjected to a driving force from a brake pedal.

In the technical scheme, the piston can seal the pressurizing oil port in the non-braking state, so that pressurized hydraulic oil can be prevented from directly entering the front cavity of the main cylinder, and the occurrence of error braking is avoided. And during braking, the piston moves towards the rear cavity of the main cylinder under the driving of the brake pedal to open the pressurizing oil port, at the moment, pressurizing hydraulic oil can enter the front cavity of the main cylinder through the pressurizing oil port to provide braking assistance for the piston, and at the moment, an oil path at the liquid supplementing port of the front cavity of the main cylinder is cut off, so that the braking effect is improved.

In the master cylinder of the present invention, the piston 2 may be a cylinder having an equal diameter. Or, in an alternative embodiment, as shown in fig. 1-4, the piston 2 has two structural forms, the piston 2 includes a large diameter section 8 and a small diameter section 9 for connecting with a brake pedal, the large diameter section 8 and the inner circumferential surface of the cylinder cavity can be matched in a sealing sliding way, the small diameter section 9 is positioned in the master cylinder front cavity 3 and forms an annular space 10 with the inner circumferential surface of the master cylinder front cavity 3, and in this case, the annular space 10 also belongs to a part of the master cylinder front cavity 3. Thus, for the pressurizing oil port 7 at the same position, compared with the piston 2 of the cylinder with the same diameter, the annular gap 10 can effectively shorten the stroke of the piston 2 for opening the pressurizing oil port 7, and is easier to provide the boosting brake. Of course, for the piston 2 of the equal-diameter cylinder, the pressurizing oil port 7 may be disposed near the end of the piston 2 facing the master cylinder front chamber 3, so that the piston 2 of the equal-diameter cylinder moves for a short stroke under the driving of the brake pedal to open the pressurizing oil port 7. In addition, the reduced portion of the small diameter section 9 relative to the large diameter section 8 also reduces the weight of the piston 2, which further reduces the weight of the master cylinder.

In addition, the sealing between the outer peripheral surface of the large-diameter section 8 and the inner peripheral surface of the cylinder cavity can be realized by various structures. For example, in one embodiment, as shown in fig. 1 and 3, a first sealing cup 11 and a second sealing cup 12 are arranged between the outer circumferential surface of the large-diameter section 8 and the inner circumferential surface of the cylinder cavity at an axial interval, wherein the first sealing cup 11 and the second sealing cup 12 are located on both axial sides of the pressurizing oil port 7 in the non-braking state. Thus, in the unbraked state, the first packing cup 11 may further prevent the flow of pressurized hydraulic oil into the front master cylinder chamber 3, while the second packing cup 12 may further prevent the flow of pressurized hydraulic oil into the rear master cylinder chamber 4.

In addition, as shown in fig. 1 and 3, the first sealing cup 11 and the second sealing cup 12 respectively include an outer lip and an inner lip which are radially spaced apart from each other, and a spaced opening is formed between the outer lip and the inner lip, and the spaced opening faces the pressurizing oil port 7. Like this, utilize the interval opening between outer lip and the interior lip, can avoid first sealed leather cup 11 and second sealed leather cup 12 to be by transition extrusion deformation, promote life to further promote sealed effect. Of course, it should be understood that the first and

second seal cups

11, 12 may have other configurations, for example, the first and

second seal cups

11, 12 may be directly a seal ring having a square block shape in cross section.

Further, the first seal cup 11 may have an arrangement, for example, as shown in fig. 1 and 2, a piston ring groove 18 is formed on the outer peripheral surface of the large diameter section 8 adjacent to the small diameter section 9, a side wall of the piston ring groove 18 facing the small diameter section 9 is a groove shoulder 14, a side wall of the groove shoulder 14 is the small diameter section 9, and the other side wall is the piston ring groove 18, and the first seal cup 11 is disposed in the piston ring groove 18. Thus, the first seal cup 11 can be stably and reliably held in the piston ring groove 18 by the positioning restriction of the groove shoulder 14 even after a long period of use, and reliable sealing performance can be ensured.

As shown in fig. 1 and 3, a third packing cup 13 is provided between the outer circumferential surface of the end portion of the large diameter section 8 facing the master cylinder rear chamber 4 and the inner circumferential surface of the cylinder chamber, and is axially spaced from the second packing cup 12. In this way, the third packing cup 13 and the second packing cup 12 together can further prevent the hydraulic oil in the rear chamber of the main cylinder from entering the front chamber of the main cylinder and the pressurizing oil port during the movement of the piston.

Similarly, the third packing cup 13 includes radially spaced outer and inner lips, respectively, forming a spaced opening therebetween facing the master cylinder rear chamber 4. Like this, utilize the interval opening between outer lip and the interior lip, can avoid third seal leather cup 13 by the excessive extrusion deformation, promote life to further promote sealed effect.

In addition, in one embodiment, as shown in fig. 3, a first annular groove, a second annular groove and a third annular groove are formed on the inner circumferential surface of the cylinder cavity at intervals in the axial direction, and the first annular groove and the second annular groove are located on two sides of the pressurizing oil port 7 in the axial direction; wherein, the first sealing leather cup 11 is arranged in the first annular groove, the second sealing leather cup 12 is arranged in the second annular groove, and the third sealing leather cup 13 is arranged in the third annular groove. Therefore, the piston ring-shaped groove 18 can be prevented from being formed on the large-diameter section of the piston, and the convenience of piston machining is improved.

The first, second and third packing cups may have a variety of configurations, for example, in one particular configuration, with reference to the configurations shown in fig. 6, 7 and 8, the packing cups include an annular body 29, the annular body 29 including an axial passage 30 for sealing engagement with the piston, one axial end of the annular body 29 including an outer lip 31 and an inner lip 32 spaced apart in a radial direction, the outer lip 31 and the inner lip 32 having a spacing space 33 therebetween; a buffer recess 35 is formed on an end surface 34 of the other axial end of the annular body 29. Since the end surface 34 of the other axial end of the annular body 29 is formed with a buffer recess 35, in use, the sealing cup is disposed in an annular groove in the mounting base member such as the main cylinder 1, while the piston is axially displaceable through the axial passage 30, in which case the inner lip 32 is pressed radially by the piston, the inner lip 32 will be pressed towards the outer lip 31 so that the spacing space 33 is reduced, since the annular body 29 has the buffer recess 35 between the end surface 34 at the other axial end thereof and the axial side surface of the annular groove, the buffer recess 35 allows the annular body 29 to be axially deformed toward the other axial end thereof, thereby reducing stress concentration of the annular body 29, even after long-term use, the annular body 29 is not damaged due to excessive concentration of internal stress caused by repeated extrusion, so that the service life of the sealing leather cup is effectively prolonged.

In the radial direction on the end face 34, the buffer recess 35 may extend from the middle of the end face 34 by the same amount in the radial direction inwardly and outwardly, so that the end face 34 retains a radially outer region and a radially inner region. Alternatively, as shown in fig. 6 and 8, the radially outer side edge 36 of the buffer recess 35 is spaced from the outer circumferential surface of the annular body 29 to form a radially outer edge region, which can abut against the axially side surface of the annular groove in practical use, while the radially inner side edge 37 of the buffer recess 35 is in contact with the inner circumferential surface of the axial passage 30, that is, the buffer recess 35 extends radially inward up to the inner circumferential surface of the axial passage 30 to form a connecting edge with the inner circumferential surface of the axial passage 30, which facilitates the deformation and extension of the annular body 29 toward the buffer recess 35 after the radial compression of the packing cup.

In addition, the cross section of the buffering concave part 35 may have various shapes, for example, a rectangular shape, a triangular shape or a semicircular shape, or any other shape, for example, as shown in fig. 8, the buffering concave part 35 is an arc-shaped concave part extending in the radial direction, so that the arc-shaped concave part can effectively reduce stress concentration when the ring-shaped body is pressed while ensuring the strength of both radial side walls of the buffering concave part 35, so that the ring-shaped body 29 is not easily damaged, and the service life is prolonged.

On the end surface 34, the buffer concave portion 35 may be a circumferentially extending groove section, for example, a plurality of circumferentially extending groove sections arranged at intervals are formed on the end surface 34, each circumferentially extending groove section forms the buffer concave portion 35, of course, the circumferential interval between the respective circumferentially extending groove sections may be set to be small, so as to enlarge the circumferentially extending distance of the circumferentially extending groove sections as much as possible, and improve the buffer effect. Alternatively, as shown in fig. 6, the buffer recess 35 extends along the circumferential direction of the ring body 29 to form an annular buffer recess, so that the buffer can be formed in the entire circumferential direction, for example, the circumferential direction, to further enhance the buffer effect.

In addition, the buffer recesses 35 may occupy respective regions of the end surface 34 as desired, for example, the buffer recesses 35 may occupy half the region of the end surface 34. Alternatively, in order to enhance the cushioning effect, as shown in fig. 8, the cushioning concave portion 35 occupies more than one-half of the area of the end surface 34, for example, the radially outer side 36 of the cushioning concave portion 35 radially exceeds the central portion of the end surface 34. In this way, the buffer recess 35 will further enlarge the buffer space between the end surface 34 and the annular groove axial side surface 25, thereby increasing the buffer effect and further reducing the stress concentration of the annular body.

Furthermore, the sealing fit of the inner peripheral surface of the axial passage 30 of the annular body 29 against the piston can be achieved by various structures, for example, a convex ring with a semicircular cross section is radially inwardly projected on the inner peripheral surface of the axial passage 30 of the annular body 29, and the convex ring can be pressed against the outer peripheral surface of the piston.

Alternatively, as shown in fig. 8, a main seal lip ring 38 and a plurality of sub seal lip rings 39 are formed on the inner circumferential surface of the axial passage 30, wherein the main seal lip ring 38 is for contacting the outer circumferential surface of the piston, and the main seal lip ring 38 protrudes radially inward. For example, the primary seal lip ring 38 may be used to contact the outer periphery of the piston. By moving the seal to function primarily as a high pressure seal and a vacuum seal. The surface of the primary seal lip 38 may be a circular arc surface that is more easily in sliding sealing contact with the outer peripheral surface of the piston. While a plurality of sub seal lip rings 39 for contacting the outer peripheral surface of the piston and arranged at an axial interval, for example, may be formed in an undulating profile in which, as shown in fig. 8, a cavity 40 is formed between adjacent sub seal lip rings 39, and the plurality of sub seal lip rings 39 are located between the main seal lip ring 38 and the end surface 34 of the other axial end of the annular body 29. For example, the plurality of secondary sealing lip rings 39 may contact the outer circumferential surface of the piston to make the cavity 40 form an annular cavity for confining brake fluid, and the annular cavity mainly stores lubricating grease, thereby improving the lubricating effect, reducing the friction force generated by the relative motion of the piston and the sealing cup, improving the transmission efficiency, and simultaneously scraping the brake fluid to prevent the oil leakage on the surface of the piston.

Of course, the sizes of the plurality of secondary seal lip rings 39 may be different from each other, for example, the outer diameter of each secondary seal lip ring 39 is arranged in order from large to small along the axial direction, but each secondary seal lip ring 39 is in press contact with the outer circumferential surface of the piston after the piston is fitted.

Alternatively, as shown in fig. 8, the plurality of secondary seal lips 39 are identical arc-shaped lips and are arranged in sequence at equal intervals, for example, may form a wave shape like a sine curve. Of course, a plurality of secondary seal lip rings 39 may be formed on the axially flat surface sections of the inner peripheral surface of the axial passage 30. Alternatively, as shown in fig. 8, the inner peripheral surface of the axial passage 30 includes an axial straight surface section 41, a first axially inclined surface section 42 and a second axially inclined surface section 43 extending radially inwardly at an inclination, wherein one end of the first axially inclined surface section 42 and the axial straight surface section 41 are connected to form the primary seal lip 38; for example, one end of the first axially-inclined surface section 42 and the axially-straight surface section 41 are connected by a radially-straight surface section 44 or by other inclined surface sections or arcuate surface sections, while the second axially-inclined surface section 43 is located between the first axially-inclined surface section 42 and the end surface 34 of the axially-other end of the annular body 29, and a plurality of secondary seal lip rings 39 are formed on the second axially-inclined surface section 43. Thus, after the plurality of secondary seal lip rings 39 are brought into contact with the outer peripheral surface of the piston, for example, the piston, due to the inclination action of the second axially inclined surface section 43, the pressing force between the secondary seal lip ring 39 at the inclined high position of the second axially inclined surface section 43 and the outer peripheral surface of the piston is greater than the pressing force between the secondary seal lip ring 39 at the inclined low position of the second axially inclined surface section 43 and the outer peripheral surface of the piston, for example, the pressing force between each secondary seal lip ring 39 and the outer peripheral surface of the piston is gradually reduced from the high position to the low position of the second axially inclined surface section 43, so that the secondary seal lip ring 39 with a large pressing force can further scrape the brake fluid and prevent oil leakage from the surface of the piston, and the secondary seal lip ring 39 with a small pressing force can increase the axial moving speed of the piston, so that the piston is relatively easy to move axially.

In one embodiment, the inner circumferential surface of the axial passage 30 is formed by an axial straight surface section 41, a first axial inclined surface section 42, and a second axial inclined surface section 43.

Of course, the angle C between the first and second axially sloping

surface sections

42, 43 may have any desired angle, for example, the angle C is greater than 0 ° and less than 10 °, preferably 2-5 °, more preferably 3 °. Of course, the angle C may be 0 °, in which case the first and second axially sloping

surface sections

42, 43 will form a continuously obliquely extending sloping plane.

In addition, as shown in fig. 8, the outer peripheral surface of the annular main body 1 includes an axially extending outer peripheral surface axial straight surface section 46 and an outer peripheral surface concave portion 45, as shown in fig. 5, after the annular main body 1 is disposed in the annular groove, the outer peripheral surface axial straight surface section 46 can be pressed against the groove bottom surface of the annular groove, but due to the outer peripheral surface concave portion 45, a cavity is formed between the outer peripheral surface of the annular main body 1 and the groove bottom surface of the annular groove, and when the annular main body 29 is extruded and deformed, the cavity can provide a deformation space for the annular main body 29, so that the internal stress concentration when the sealing cup is extruded and deformed is further reduced, the damage to the sealing cup is reduced, and the service life is prolonged.

Further, as shown in fig. 6 and 8, the master cylinder further includes a spring 15; axial holes are respectively formed in two axial end faces of the piston 2, and the two axial holes can reduce the weight of the piston 2; a push rod 5 axially penetrates out of the main cylinder front cavity 3 for connecting a brake pedal is arranged in one axial hole, the push rod 5 can be matched with the main cylinder body 1 in a sealing and sliding mode through a push rod sealing ring 19, one end of a spring 15 is contained and positioned in the other axial hole, and the other end of the spring 15 is connected to a main cylinder end cover 16 of the main cylinder body 1.

In addition, in the master cylinder of the present application, the master cylinder rear chamber 4 may have one, two, or three or more if necessary.

Finally, the present application provides a hydraulic brake system provided with the master cylinder as described above. As above, the braking performance and the safety performance of the hydraulic braking system are effectively improved.

In the hydraulic brake system shown in fig. 5, the brake master cylinder has two master cylinder rear chambers 4, and the two master cylinder rear chambers 4 are connected to brake oil passages through respective oil outlets 17. The fluid replenishing port 6 is connected to a pressure medium storage container 27 such as a fluid reservoir through a solenoid valve 28, and the pressurizing port 7 is connected to the hydraulic accumulator 23 through a master cylinder pressurizing control valve 21.

When the hydraulic braking system is normal, the brake pedal 20 pushes the piston 2 to move forward through the push rod 5, oil between the pressurizing oil port 7 and the hydraulic accumulator 23 is cut off by the master cylinder pressurizing control valve 21, and a pipeline between the fluid supplementing port 6 and the liquid storage pot is communicated, so that when the push rod pushes the piston to move forward, the volume of the master cylinder front cavity 3 is continuously increased, and the master cylinder front cavity 3 can supplement fluid through the fluid supplementing port 6 continuously, and the master cylinder front cavity 3 cannot generate negative pressure. At this time, the motor M drives the brake pump 22 to push hydraulic oil in the pressure chamber of the brake pump 22 into the wheel cylinder through the brake oil path.

When the braking system is powered off or the motor fails, the master cylinder pressure-increasing control valve 21 is opened to communicate the pipeline between the pressure-increasing oil port 7 and the hydraulic energy accumulator 23, when the brake pedal is stepped on by a foot, the push rod pushes the piston to move forwards, the pressure-increasing oil port 7 is conducted at the moment, high-pressure oil in the hydraulic energy accumulator 23 enters a front cavity of the master cylinder through the pressure-increasing oil port 7, the force of the high-pressure oil and the push rod jointly acts on the piston 2 to push the piston 2 to move forwards, and therefore the failure assisting effect is achieved, and the problems that when the motor or the braking system is powered off, the braking force is totally determined by the pedal force, the pedal is hard and the like are solved.

Additionally, in FIG. 5, the hydraulic accumulator pressure sensor 25 may feed back a pressure signal from the hydraulic accumulator 23 to a controller of the hydraulic brake system, resulting in regulation and control of the pressure of the hydraulic accumulator 23.

The hydraulic accumulator 23 can be replenished with pressure oil by the brake pump 22, for example, the hydraulic accumulator pressure sensor 25 sends the pressure state value of the hydraulic accumulator to the controller of the hydraulic brake system, if the monitored value is less than the system initial specification requirement, the oil return control valve 26 is closed by energization, the master cylinder pressure increasing control valve 21 is closed by energization, the solenoid valves POV2 and DFL are opened by energization, the solenoid valve HFL is opened by deenergization, the solenoid valve SMV1 is closed by energization, so that the pipeline between the brake pump 22 and the hydraulic accumulator 23 is communicated, and thus, the pressurized hydraulic oil in the brake pump 22 enters the hydraulic accumulator 23 through the solenoid valve POV2, the solenoid valve HFL, the solenoid valve DFL and the accumulator oil supply check valve 24.

Furthermore, the invention provides a vehicle provided with a hydraulic brake system as described above.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A brake master cylinder, comprising:

the cylinder comprises a main cylinder body (1), wherein a cylinder cavity is formed in the main cylinder body (1);

a piston (2), wherein the piston (2) is arranged in the cylinder cavity in a sealing sliding manner and divides the cylinder cavity into a main cylinder front cavity (3) and a main cylinder rear cavity (4);

the main cylinder rear cavity (4) is provided with an oil inlet and an oil outlet; the master cylinder front cavity (3) is provided with a liquid supplementing port (6) and a pressurizing oil port (7);

the piston (2) can close the pressurizing oil port (7) in an unbraked state, and the piston (2) can move toward the master cylinder rear chamber (4) to open the pressurizing oil port (7) when receiving a driving force from a brake pedal.

2. A brake master cylinder according to claim 1, wherein the piston (2) includes a large diameter section (8) and a small diameter section (9) for connection with a brake pedal, the large diameter section (8) and an inner peripheral surface of the cylinder chamber are sealingly slidably fitted, and the small diameter section (9) is located in the master cylinder front chamber (3) and forms an annular space (10) with the inner peripheral surface of the master cylinder front chamber (3).

3. The master cylinder according to claim 2, characterized in that a first sealing cup (11) and a second sealing cup (12) are axially spaced apart from each other between the outer circumferential surface of the large diameter section (8) and the inner circumferential surface of the cylinder cavity, wherein the first sealing cup (11) and the second sealing cup (12) are located on both axial sides of the pressurizing oil port (7) in the non-braking state.

4. A brake master cylinder according to claim 3, characterized in that the first and second sealing cups (11, 12) respectively comprise radially spaced outer and inner lips, forming a spaced opening therebetween facing the pressure-increasing oil port (7).

5. The master cylinder according to claim 3, wherein a piston ring groove (18) is formed on the outer peripheral surface of the large diameter section (8) adjacent to the small diameter section (9), a side wall of the piston ring groove (18) facing the small diameter section (9) serves as a groove shoulder (14), a side wall of the groove shoulder (14) serves as the small diameter section (9) and the piston ring groove (18), and the first seal cup (11) is disposed in the piston ring groove (18).

6. A brake master cylinder according to claim 3, characterized in that a third sealing cup (13) is arranged between the outer circumferential surface of the end of the large-diameter section (8) facing the master cylinder rear chamber (4) and the inner circumferential surface of the cylinder chamber, axially spaced from the second sealing cup (12).

7. A brake master cylinder according to claim 6, characterized in that the third sealing cup (13) comprises an outer lip and an inner lip, respectively, arranged radially at a distance from each other, forming a spaced opening therebetween, said spaced opening facing the master cylinder rear chamber (4).

8. The brake master cylinder according to claim 6, wherein first, second and third axially spaced annular grooves are formed on an inner peripheral surface of the cylinder chamber, the first and second annular grooves being located on both axial sides of the pressurizing oil port (7);

wherein the content of the first and second substances,

first sealed leather cup (11) set up in the first ring channel, second sealed leather cup (12) set up in the second ring channel, third sealed leather cup (13) set up in the third ring channel.

9. The master cylinder according to any one of claims 1 to 8, further comprising a spring (15);

axial holes are respectively formed on two axial end faces of the piston (2);

a push rod (5) axially penetrates out of the master cylinder front chamber (3) and is used for connecting a brake pedal is arranged in one axial hole;

one end of the spring (15) is accommodated and positioned in the other axial hole, and the other end of the spring (15) is connected to a main cylinder end cover (16) of the main cylinder body (1).

10. A hydraulic brake system, characterized in that it is provided with a master cylinder according to any of claims 1-9.

11. A vehicle characterized in that the vehicle is provided with the hydraulic brake system according to claim 10.