TWI577588B - Brake master cylinder - Google Patents

Description

Brake master cylinder

The invention relates to a hydraulic brake device, and aims to provide a pressure increase amount which can gradually increase or decrease the O-ring when the piston reciprocates, thereby making the brake reaction more rapid and sensitive, and obtaining a better operation feeling. Brake master cylinder.

Press, the hydraulic brake device used by locomotives or bicycles should be regarded as one of the most commonly used hydraulic devices. It is known that the conventional brake master cylinders are as shown in Figure 1, which is used to install the brake handlebars. The handle base 11 is provided with an oil storage space 111 for filling hydraulic oil and a main oil cylinder 112 for connecting hydraulic lines (not shown), and an inner brake cylinder 112 is provided with an installed handlebar handlebar. The piston 12 that drives the reciprocating displacement is provided with a ring groove 121 at a portion of the piston 12 that extends into the main sump 112. An O-ring 122 is sleeved at the ring groove 121.

Mainly during the movement of the piston 12 toward the main cylinder 112, the hydraulic oil in the main cylinder 112 is transmitted by the piston 12 through the connected hydraulic line to the brake caliper (not shown) of the wheel, so that the brake caliper is generated on the wheel.挚 Action.

However, in the actual operation of the conventional brake master cylinder, the O-ring 122 always maintains the same pressure-matching amount during the reciprocating process of the piston 12. In order to obtain the proper pressure leakage resistance, the pressure-matching amount of the O-ring 122 must be increased. The design, because the O-ring pressure ratio is proportional to the frictional resistance when moving.

Relatively, the piston 12 must bear the same resistance during the forward or reverse retraction of the hydraulic pressure to the brake caliper, so it will be relatively expensive when the brake action is performed. Force, and when the brake action is completed, the retracting and resetting action of the piston and the driver will be slower, which will not only affect the sensitivity and operation feel of the brake action.

In view of the above, the present invention provides a brake master cylinder capable of gradually increasing or decreasing the pressure distribution of the O-ring when the piston is reciprocatingly displaced, thereby making the braking reaction faster and more sensitive, and obtaining a better operating feel. For its main purpose.

In order to achieve the above object, the brake master cylinder of the present invention is connected to a handle for mounting a brake handle, and an oil storage space for loading hydraulic oil and a main oil cylinder for connecting with the hydraulic pipeline. The main cylinder is internally provided with a piston which can be reciprocally displaced by the mounted handlebar. The piston is provided with a ring groove at least at a portion thereof extending into the main cylinder, and a ring groove is arranged at the ring groove. a first O-ring; the piston is attached to the groove bottom of the ring groove, and at least a buffer portion is formed in a slope shape, the buffer segment is inclined toward one end of the main cylinder; and the ring The distance between the two groove walls of the groove is such that when the piston reciprocates, the first O-ring can be changed relative to the position of the buffer segment, and the piston is reciprocally displaced during the process. The first O-ring produces different degrees of expansion, so that the first O-ring produces different press-fit and pressure leakage resistance.

According to the above technical feature, when the brake master cylinder of the present invention performs the braking action by pressing the driver's handle, the first O-ring is displaced in a direction opposite to the moving direction of the piston due to the reaction force of the hydraulic oil, that is, gradually moving toward the buffer zone. The displacement of the height is gradually increased by the buffer section to the expansion of the first O-ring, so that the first O-ring gradually increases the pressure-matching amount and the pressure leakage resistance; in particular, in the initial state in which the piston moves toward the main cylinder, Since the first O-ring is still in a relatively small amount of press-fit, it is possible to quickly push the piston to transfer the hydraulic oil of the main cylinder to the brake caliper with a relatively small pressing force, thereby achieving a better operating feel; When it is sufficient to cause a smashing action on the wheel, the first O-ring is also fitted to a position where the pressure-matching amount is relatively large, and In order to produce the maximum pressure leakage, and thus achieve a relatively stable and reliable brake swaying effect; and, when the slamming force is pressed against the rider, the first O-ring can be affected by the slope of the buffer zone. Quickly move to the buffer section toward one end of the main cylinder, quickly reduce the pressure distribution and pressure leakage of the first O-ring, so that the piston and the brake handle can be quickly reset, making the brake response faster and more sensitive.

According to the above technical feature, the oil storage space is disposed at an axial position of the handle base relative to the main cylinder, and the handle seat is provided with an oil hole for connecting with the hydraulic line with respect to one end of the main cylinder The handle seat is provided with a mounting hole at one end of the oil storage space; a sleeve corresponding to the main oil cylinder is disposed inside the oil storage space of the handle seat, and the piston has a first portion extending from the one end of the sleeve a two-ring ring; a fixing seat is disposed at the mounting hole of the handle seat, the fixing seat has a positioning sleeve extending into the oil storage space for engaging with the sleeve, and another hole is disposed at a center of the positioning sleeve The piston is connected to the pull rod; the stop seat and the handle base are lined with a leakage stop member, and the leakage stop member integrally extends with a sleeve covering the positioning sleeve of the fixing seat and the sleeve.

According to the above technical feature, the piston is formed with a turning section between the buffer section toward one end of the main cylinder and an adjacent groove wall.

According to the above technical feature, the slope of the buffer segment is between 5 and 50 degrees.

According to the above technical feature, the distance between the two groove walls of the annular groove is greater than the thickness of the first O-ring by at least 0.1 mm.

According to the above technical feature, the piston is formed with a turning section between the buffer section toward one end of the main cylinder and an adjacent groove wall; the slope of the buffer section is between 5 and 50 degrees. And, the distance between the two groove walls of the annular groove is greater than the thickness of the first O-ring by at least 0.1 mm.

The buffer section is in the form of a straight slope.

The buffer section has a beveled shape.

The sleeve end is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged.

The sleeve end is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged; the handle seat is formed at an interface between the main oil cylinder and the oil storage space. The sleeve and the sleeve are inserted into the class.

The front end of the leakage stop member is provided with an outer flange for being sandwiched between the assembly hole and the fixing seat.

The handle base is provided with at least one first oil return hole connected to the oil storage space in the main cylinder for reciprocating the first O ring.

The sleeve is provided with at least one second oil return hole connected to the oil storage space.

The handle is provided at the reciprocating motion of the main cylinder for at least one first oil return hole connected to the oil storage space; the sleeve is provided with at least one second connected to the oil storage space Return oil hole.

A spring is disposed between the main cylinder and the piston.

The handle base is formed at a position where the main oil cylinder is opposite to the first oil return hole, and an oil return section having an inner diameter relatively larger than an outer diameter of the first O-ring is formed.

The piston is provided with a necked section at a position relative to the first O-ring and the second O-ring.

The piston is provided with a ball seat opposite to one end of the fixed seat, and the pull rod is provided with a ball end that is sleeved with the ball seat; the pull rod is pivotally connected to the mounted brake handle through a rotating shaft.

The pull rod is pivotally connected to the installed handlebar handle through a rotating shaft; the rod body of the pull rod is provided with a threaded section, and the rotating shaft is provided with a screw hole for screwing with the threaded section of the pull rod. .

The brake master cylinder of the present invention is connected to a handlebar for mounting a handlebar handlebar An oil storage space for loading hydraulic oil and a main oil cylinder connected to the hydraulic pipeline are provided, and a piston which can be reciprocally displaced by the installed handlebar is provided inside the main cylinder, the piston system is at least in its opposite a ring groove is formed in the ring extending into the main oil cylinder, and a first O-ring is sleeved in the ring groove; the piston is attached to the bottom of the groove of the ring groove, and at least one beveled surface is formed. a buffer segment that is inclined toward one end of the main cylinder; and a distance between the two groove walls of the ring groove is adapted to be changed by the first O-ring when the piston reciprocates Relative to the position of the buffer zone; the oil storage space is disposed at an axial position of the handle base relative to the main cylinder, and the handle seat is provided with an oil hole for the end of the main cylinder a hydraulic pipe connection, the handle base is provided with a mounting hole at one end of the oil storage space; a sleeve corresponding to the main oil cylinder is disposed inside the oil storage space of the handle seat, and the piston extends into the sleeve One end is provided with a second O-ring; the mounting hole of the handle is provided a fixing seat having a positioning sleeve extending into the oil storage space for engaging with the sleeve, and a pull rod connected to the piston is disposed at a center of the positioning sleeve; the fixing seat and the handle Between the seats is provided with a leakage stop element, the leakage stop element integrally extends with a sleeve covering the positioning sleeve of the fixing seat and the sleeve; the piston is tied to the buffer section toward one end of the main cylinder a turn-over section is formed between the adjacent groove walls; the sleeve end is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged; the handle is seated in the main cylinder Forming a joint with the sleeve and the sleeve; the front end of the leak stop member is provided with an outer flange for being relatively sandwiched between the assembly hole and the mount Providing at least one first oil return hole connected to the oil storage space at the reciprocating motion of the main cylinder for the first O-ring; the sleeve is provided with at least one connected to the oil storage space a second oil return hole; a spring is disposed at a position between the main cylinder of the handle and the piston The handlebar is formed at a position opposite to the first oil return hole of the main cylinder to form an oil return section having an inner diameter relatively larger than an outer diameter of the first O-ring: the piston is opposite to the first O-ring a necking section is disposed at a position between the second O-ring: the piston is provided with a ball seat opposite to one end of the fixing base, and the rod is provided with a ball end that is sleeved with the ball seat; Through a rotating shaft and installed 煞 The driver is pivotally connected; the rod body of the pull rod is provided with a threaded section, and the rotating shaft is provided with a screw hole for screwing with the threaded section of the rod.

Specifically, the brake master cylinder disclosed in the present invention can produce the following effects:

1. When the piston reciprocates, it can gradually increase or decrease the pressure distribution of the O-ring, so that the braking reaction is faster and more sensitive.

2. When the piston reciprocates, it can gradually increase or decrease the pressure distribution of the O-ring, thereby achieving a better operating feel.

3. It is still possible to use the passage formed by the assembly hole, and sequentially put the piston, the sleeve and the leakage preventing component into the main cylinder and the oil storage space of the handle base, and finally install the fixing seat with the tie rod on the handle. At the assembly hole of the seat, the assembly of the overall brake master cylinder can be completed quickly.

4. Under the action of the leakage preventing component, the hydraulic oil can be prevented from leaking through the assembly hole, the hydraulic oil can be prevented from leaking from the joint between the sleeve and the positioning sleeve, and the hydraulic oil can be prevented from being pulled by the second O-ring. The outer leakage of the wearing device can produce a better sealing effect on the hydraulic oil.

11‧‧‧handle

111‧‧‧ oil storage space

112‧‧‧Main cylinder

12‧‧‧Piston

121‧‧‧ Ring groove

122‧‧‧O-ring

20‧‧‧煞 rider

30‧‧‧handle

31‧‧‧ oil storage space

311‧‧‧Assembly holes

32‧‧‧Main cylinder

321‧‧‧ oil hole

322‧‧‧Return section

33‧‧‧ sleeve

331‧‧‧second oil hole

332‧‧‧ Ring groove

34‧‧‧ fixed seat

341‧‧‧ positioning sleeve

35‧‧‧ lever

351‧‧‧ ball end

352‧‧‧ thread section

36‧‧‧ leak-stop components

361‧‧‧ casing

3611‧‧‧ inner flange

37‧‧‧First oil hole

40‧‧‧Piston

41‧‧‧ Ring groove

411‧‧‧Buffer segment

412‧‧‧ turning section

42‧‧‧First O-ring

43‧‧‧Second O-ring

44‧‧‧neck section

45‧‧‧ tee

50‧‧‧ Spring

60‧‧‧ shaft

61‧‧‧ screw holes

Figure 1 is a partial enlarged cross-sectional view of a conventional brake master cylinder.

Figure 2 is a cross-sectional view showing the structure of a brake master cylinder according to a preferred embodiment of the present invention.

Fig. 3 is a partially enlarged cross-sectional view showing the piston portion of the brake master cylinder of the present invention in a normal state.

Fig. 4 is a schematic view showing the action of the brake master cylinder of the present invention in the pressing state of the brake handlebar.

Fig. 5 is a partially enlarged cross-sectional view showing the piston portion of the brake master cylinder of the present invention in a pressed state of the brake handlebar.

Fig. 6 is a comparison diagram of the piston actuation resistance, the O-ring pressure-matching amount and the handle actuation curve of the brake master cylinder and the conventional brake master cylinder of the present invention.

Figure 7 is a partially enlarged cross-sectional view showing the piston in the annular groove portion of the second embodiment of the present invention.

Figure 8 is a partially enlarged cross-sectional view showing the piston in the annular groove portion of the third embodiment of the present invention.

Figure 9 is a partially enlarged cross-sectional view showing the piston in the annular groove portion of the fourth embodiment of the present invention.

The invention mainly provides a brake master cylinder capable of gradually increasing or decreasing the pressure distribution of the O-ring when the piston reciprocates, thereby making the braking reaction more rapid and sensitive, and obtaining a better operating feel. For a clear understanding of the drawings and the detailed description of the embodiments.

2 is a cross-sectional view showing the structure of a brake master cylinder according to a preferred embodiment of the present invention, and FIG. 3 is a partially enlarged cross-sectional view showing the piston portion of the brake master cylinder of the present invention in a normal state, and the brake master cylinder of the present invention is used in one embodiment. An oil storage space 31 for loading hydraulic oil and a main oil cylinder 32 for connecting with a hydraulic line (not shown) are connected to the handlebar 30 of the driver's handlebar 20, and a main cylinder 32 is provided inside the main cylinder 32. The mounted handlebar 20 drives a reciprocating displacement piston 40. The piston 40 is provided with a ring groove 41 at least at a portion thereof extending into the main cylinder 32, and a first sleeve is disposed at the ring groove 41. O ring 42; characterized by:

The piston 40 is fastened to the bottom of the groove of the annular groove 41, and at least one buffered section 411 is formed. The buffer section 411 is inclined toward one end of the main cylinder 32; and the two of the annular grooves 41 The distance between the groove walls is such that when the piston 40 is reciprocally displaced, the first O-ring 42 can be changed relative to the position of the buffer zone 411 by the reciprocating displacement of the piston 40. The first O-ring 42 produces different degrees of expansion, so that the first O-ring 42 produces different press-fit and pressure leakage resistance.

In principle, the brake master cylinder of the present invention can be used in the handlebar 30 when in use. A suitable handlebar handle 20 is mounted thereon, and the handlebar handle 30 is attached to the rider or bicycle rider (not shown), and the main cylinder 32 and the brake caliper are formed through hydraulic lines (not shown). Figure omitted) oil circuit connection.

In the normal state, the first O-ring 42 is subjected to the slope of the buffer section 411, and is stopped at the buffer section 411 toward one end of the main cylinder 32. As shown in FIGS. 4 and 5, by pressing the brake handlebar 20 During the braking operation, during the movement of the piston 40 toward the main cylinder 32, the first O-ring 42 is displaced in a direction opposite to the moving direction of the piston 40 by the reaction force of the hydraulic oil, that is, gradually moving toward the buffer section 411. When the displacement is high, the expansion of the first O-ring 42 is gradually increased by the buffer section 411, so that the first O-ring 42 gradually increases the press-fit amount and the pressure leakage resistance.

In particular, in the initial state in which the piston 40 is moved toward the main cylinder 32, since the first O-ring 42 is still in a relatively small amount of press-fit amount, the piston 40 can be quickly pushed with a relatively small pressing force to move the main cylinder 32. The hydraulic oil is transferred to the brake caliper for better handling (as shown in Figure 6); when the piston 40 is moved to deliver sufficient hydraulic oil to the brake caliper to cause the brake caliper to smash the wheel ( That is, when the piston 40 is moved enough to cause a smashing action on the wheel, the first O-ring 42 is also fitted to a position where the pressure-matching amount is relatively large, and the pressure-matching amount generated by the first O-ring 42 is greater than the hydraulic oil. The pressure, as shown in Fig. 6, is that the handle stroke is 6mm, and the pressure of the first O-ring 42 is increased from 20% to 90%. At this time, the maximum pressure leakage can be generated, and the relative pressure is relatively high. Stable and reliable braking effect.

And, when the pressing force of the handlebar 20 is loosened, the piston 40 can be displaced away from the retracting direction of the main cylinder 32 under the action of the springs of the brake caliper or the rest of the spring in the oil passage. The O-ring 42 can be moved by the slope of the buffer section 411 to quickly move to the buffer section 411 toward one end of the main cylinder 32. As shown in FIGS. 2 and 3, the press-fit amount of the first O-ring 42 is rapidly lowered. And the pressure leakage, the piston 40 and the brake driver 20 can be quickly reset, so that the brake response is faster and more sensitive.

In the implementation of the brake master cylinder of the present invention, the oil storage space 31 is provided in the hand With respect to the axial position of the seat 30 relative to the main cylinder 32, the handle base 30 is provided with an oil outlet 321 at one end of the main cylinder 32 for connection with a hydraulic line. The handle base 30 is opposite to the reservoir. One end of the oil space 31 is provided with a mounting hole 311. The oil storage space 31 of the handle base 30 is internally provided with a sleeve 33 that engages with the main oil cylinder 32. The piston 40 is opposite to one end of the sleeve 33 and is provided with a second portion. The O-ring 43 is provided with a fixing seat 34 at the mounting hole 311 of the handle holder 30. The fixing seat 34 has a positioning sleeve 341 extending into the oil storage space 31 for engaging with the sleeve 33. A pull rod 35 connected to the piston 40 is disposed at a center of the 341. The retaining seat 34 and the handle base 30 are lined with a leakage stop member 36. The leakage stop member 36 integrally extends to the fixed seat 34. The positioning sleeve 341 and the sleeve 361 covered by the sleeve 33.

In the above configuration, the piston 40, the sleeve 33 and the leakage preventing member 36 are sequentially placed into the main cylinder 32 of the handle base 30 and the oil storage space 31 by using the passage formed by the fitting hole 311, and finally The fixing seat 34 provided with the tie rod 35 is mounted on the fitting hole 311 of the handle base 30, so that the assembly of the integral brake master cylinder can be completed quickly; and the hydraulic oil can be prevented from passing through the assembly hole under the action of the leakage preventing member 36. The outer leakage of the 311 prevents the hydraulic oil from leaking from the joint between the sleeve 33 and the positioning sleeve 341, and prevents the hydraulic oil from leaking from the through portion of the rod 35 under the action of the second O-ring 43 to generate hydraulic oil. Good sealing effect.

The end of the sleeve 361 may be further provided with an inner flange 3611. The outer periphery of the sleeve 33 is provided with a ring groove 332 for the inner flange 3611 to be engaged. The edge of the sleeve 33 is provided with a ring groove 332 for the inner flange 3611 to be engaged, and the handle base 30 can be fitted to the main oil cylinder 32 and the oil storage space 31. A joint is formed in the joint portion for inserting the sleeve 33 and the sleeve 361 to strengthen the joint effect of the sleeve 33 and the sleeve 361. As a result, the front end of the leak stop member 36 may be provided with a relative clamping. The outer flange between the mounting hole 311 and the fixing seat 34 ensures the sealing effect between the fixing seat 34 and the fitting hole 311.

The handle base 30 can be reciprocated by the first O-ring 42 in the main cylinder 32 The movable portion is provided with at least one first oil return hole 37 connected to the oil storage space 31; the sleeve 33 may also be provided with at least one second oil return hole 331 connected to the oil storage space 31; of course, the whole The brake master cylinder is provided with at least one first oil return hole 37 connected to the oil storage space 31, and the sleeve 33 on the main cylinder 32 for reciprocating the first O-ring 42 Preferably, a structural form of at least one second oil return hole 331 connected to the oil storage space 31 is provided.

So that the hydraulic oil in the oil storage space 31 can automatically fill the hydraulic line of the front end of the first O-ring 42 via the first oil return hole 37 in a state where the piston 40 is completely retracted, without causing the brake oil to be braked. The piece wears to return the rider 20 to a predetermined angle and maintains the desired braking effect, and allows hydraulic oil to enter the sleeve 33 through the second oil return hole 331 to increase the piston 40 and the sleeve 33. Lubrication effect.

Furthermore, a spring 50 may be disposed between the main cylinder 32 and the piston 40, and the spring 50 may be used to generate a force for the piston 40 to be retracted and resetted when the knight releases the handlebar. With a relatively more active and reliable means, the piston is retracted and the rider's handle that is coupled to the piston is returned to a predetermined angle.

Moreover, the handle base 30 can form an oil return section 322 having an inner diameter relatively larger than the outer diameter of the first O-ring 42 at a position where the main oil cylinder 32 is opposite to the first oil return hole 37, so as to be opposite. Speeding up the passage of the first O-ring 42 through the first oil return hole 37; and the piston 40 may be provided with a necking at a position relative to the first O-ring 42 and the second O-ring 43 Section 44, the necking section 44 can be utilized to contain hydraulic oil to increase the lubrication of the reciprocating motion of the piston 40.

For example, the piston 40 can also be provided with a ball seat 45 at one end thereof opposite to the fixing base 34. The rod 35 is provided with a ball end 351 which is sleeved with the ball seat 45; the rod 35 is transmitted through a rotating shaft. 60 is pivotally connected to the installed cymbal driver 20; and, in the structural form in which the lever 35 is pivotally connected to the mounted cymbal driver 20 via a rotating shaft 60, the lever 35 is provided on the shaft There is a thread section 352, and the shaft 60 is provided with a screw for the rod 35 The threaded hole 61 of the tooth section 352 is screwed so that the angle of the handlebar 20 is adjusted by rotating the lever 35.

It is worth mentioning that, in the embodiment shown in Figures 2 to 5, the piston 40 is formed between the buffer section 411 toward one end of the main cylinder 32 and its adjacent groove wall. There is a turning section 412; of course, the piston 40 can also be shown in the structural form of only the buffer section 411 at the bottom of the groove of the ring groove 41 as shown in Figs. 8 and 9.

Moreover, the piston 40 forms a turning section 412 between the buffer section 411 toward one end of the main cylinder 32 and its adjacent groove wall; in practice, the slope of the buffer section 411 is between Preferably, between 5 and 50 degrees; and the distance between the two groove walls of the annular groove 41 is greater than the thickness of the first O-ring 42 of at least 0.1 mm.

Similarly, the piston 40 forms a turning section 412 between the buffer section 411 toward one end of the main cylinder 32 and its adjacent groove wall, and the buffer section 411 can be as shown in FIG. Or a straight beveled shape as shown in Fig. 8; or a beveled shape of the protuberances as shown in Figs. 7 and 9.

Compared with the conventional conventional structure, the brake master cylinder disclosed in the present invention can produce the following effects:

1. When the piston reciprocates, it can gradually increase or decrease the pressure distribution of the O-ring, so that the braking reaction is faster and more sensitive.

2. When the piston reciprocates, it can gradually increase or decrease the pressure distribution of the O-ring, thereby achieving a better operating feel.

3. It is still possible to use the passage formed by the assembly hole, and sequentially put the piston, the sleeve and the leakage preventing component into the main cylinder and the oil storage space of the handle base, and finally install the fixing seat with the tie rod on the handle. At the assembly hole of the seat, the assembly of the overall brake master cylinder can be completed quickly.

4. Under the action of the leakage preventing component, the hydraulic oil can be prevented from leaking through the assembly hole, the hydraulic oil can be prevented from leaking from the joint between the sleeve and the positioning sleeve, and the hydraulic oil can be prevented from being pulled by the second O-ring. The outer leakage of the wearing device can produce a better sealing effect on the hydraulic oil.

In summary, the present invention provides a preferred and feasible brake master cylinder, and an application for an invention patent according to the law; the technical content and technical features of the present invention have been disclosed above, but those skilled in the art may still be based on the present invention. The disclosure is made without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims

30‧‧‧handle

31‧‧‧ oil storage space

32‧‧‧Main cylinder

322‧‧‧Return section

33‧‧‧ sleeve

331‧‧‧second oil hole

332‧‧‧ Ring groove

35‧‧‧ lever

351‧‧‧ ball end

361‧‧‧ casing

3611‧‧‧ inner flange

37‧‧‧First oil hole

40‧‧‧Piston

41‧‧‧ Ring groove

411‧‧‧Buffer segment

412‧‧‧ turning section

42‧‧‧First O-ring

43‧‧‧Second O-ring

44‧‧‧neck section

45‧‧‧ tee

50‧‧‧ Spring

Claims (19)

The utility model relates to a brake master cylinder, which is connected with a storage space for loading hydraulic oil and a main oil cylinder for connecting with a hydraulic pipeline, and a main oil cylinder connected to the hydraulic pipeline is provided on the handle base for installing the brake handlebar. The mounted handlebar handles a reciprocating displacement piston, the piston is provided with a ring groove at least at a portion thereof extending into the main cylinder, and a first O-ring is sleeved at the ring groove; The piston is at the bottom of the groove of the annular groove, and at least a buffer portion is formed in a slope shape, the buffer segment is inclined downward toward one end of the main cylinder, and the piston is attached to the buffer cylinder toward the main cylinder Forming a turning section between one end and the adjacent groove wall; the slope of the buffer section is between 5 and 50 degrees; and the distance between the two groove walls of the ring groove is greater than the The thickness of the first O-ring is at least 0.1 mm; the distance between the two groove walls of the ring groove is such that when the piston is reciprocally displaced, the first O-ring can be changed relative to the position of the buffer segment , the first O-ring is different during the reciprocating displacement of the piston The degree of expansion causes the first O-ring to produce different press-fit and pressure leakage resistance. The brake master cylinder according to claim 1, wherein the oil storage space is disposed at an axial position of the handle base relative to the main cylinder, and the handle seat is provided with an oil with respect to one end of the main cylinder. The hole is connected to the hydraulic pipeline, and the handle seat is provided with a mounting hole at one end of the oil storage space; a sleeve corresponding to the main oil cylinder is disposed inside the oil storage space of the handle seat, and the piston extends into the sleeve One end of the sleeve is provided with a second O-ring; a fixing seat is arranged at the mounting hole of the handle, the fixing seat has a positioning sleeve extending into the oil storage space for engaging with the sleeve, and the positioning sleeve is further The center of the rod is provided with a pull rod connected to the piston; the fixing seat is lined with the handle base A leakage stop member integrally extends with a sleeve covering the positioning sleeve of the fixing seat and the sleeve. A brake master cylinder according to claim 1 or 2, wherein the piston is formed with a turning section between the buffer section toward one end of the main cylinder and an adjacent groove wall. The brake master cylinder according to claim 1 or 2, wherein the buffer section has a slope of between 5 and 50 degrees. The brake master cylinder of claim 1 or 2, wherein the distance between the two groove walls of the annular groove is greater than the thickness of the first O-ring by at least 0.1 mm. The brake master cylinder according to claim 1 or 2, wherein the buffer section has a straight slope shape. The brake master cylinder according to claim 1 or 2, wherein the buffer section has a beveled shape. The brake master cylinder according to claim 2, wherein the sleeve end is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged. The brake master cylinder of claim 2, wherein the sleeve end is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged; the handle is seated on the main A joint between the cylinder and the oil reservoir space is formed for the sleeve and the sleeve to be inserted. The brake master cylinder according to claim 2, wherein the front end of the leakage stop member is provided with an outer flange for being sandwiched between the fitting hole and the fixing seat. The brake master cylinder according to claim 2, wherein the handle base is provided with at least one first oil return hole connected to the oil storage space in the main cylinder for reciprocating the first O-ring. The brake master cylinder according to claim 2, wherein the sleeve is provided with at least one second oil return hole connected to the oil storage space. The brake master cylinder according to claim 2, wherein the handle is provided in the main cylinder for reciprocating the first O-ring, and at least one first oil return hole connected to the oil storage space is provided; At least one second oil return hole connected to the oil storage space is provided. The brake master cylinder according to claim 1 or 2, wherein a spring is disposed between the master cylinder and the piston. The brake master cylinder according to claim 11, wherein the handle base is formed at a position where the main oil cylinder is opposite to the first oil return hole, and an oil return section having an inner diameter relatively larger than an outer diameter of the first O-ring is formed. . The brake master cylinder of claim 2, wherein the piston is provided with a necked section at a position relative to the first O-ring and the second O-ring. The brake master cylinder of claim 2, wherein the piston is provided with a ball seat opposite to one end of the fixed seat, the pull rod is provided with a ball end that is sleeved with the ball seat; the pull rod is transmitted through a rotating shaft The installed rider handles the pivotal connection. The brake master cylinder according to claim 2, wherein the pull rod is pivotally connected to the installed brake handle through a rotating shaft; the rod body of the pull rod is provided with a threaded section, and the rotating shaft is provided with a A threaded hole in which the threaded portion of the tie rod is screwed. The utility model relates to a brake master cylinder, which is connected with a storage space for loading hydraulic oil and a main oil cylinder for connecting with a hydraulic pipeline, and a main oil cylinder connected to the hydraulic pipeline is provided on the handle base for installing the brake handlebar. The mounted rider handles a reciprocating displacement piston that is at least a ring groove is disposed in the ring portion of the main oil cylinder, and a first O-ring is sleeved at the ring groove. The piston is attached to the groove bottom of the ring groove, and at least one of the ring holes is formed. a beveled buffer segment that is inclined toward one end of the main cylinder; and a distance between the two groove walls of the annular groove is available for the first O when the piston reciprocates The ring changes its position relative to the buffer section; the oil storage space is disposed at an axial position of the handle base relative to the main cylinder, and the handle seat is provided with an oil hole with respect to one end of the main cylinder Provided for connection with a hydraulic pipe, the handle seat is provided with a mounting hole at one end of the oil storage space; a sleeve corresponding to the main oil cylinder is disposed inside the oil storage space of the handle seat, and the piston extends into the sleeve One end of the cylinder is provided with a second O-ring; a fixing seat is arranged at the mounting hole of the handle, the fixing seat has a positioning sleeve extending into the oil storage space for engaging with the sleeve, and the positioning sleeve is further The center is provided with a pull rod connected to the piston; the fixed seat and the handle seat The lining is provided with a leakage stop member integrally extending with a sleeve covering the positioning sleeve of the fixing seat and the sleeve; the piston is tied to the groove adjacent to the one end of the main cylinder Forming a turning section between the walls; the end of the sleeve is provided with an inner flange, and the outer ring of the sleeve is provided with a ring groove for the inner flange to be engaged; the handle is seated in the main cylinder and the storage a joint of the oil space is formed with a sleeve for inserting the sleeve and the sleeve; the front end of the leakage stop member is provided with an outer flange for being sandwiched between the assembly hole and the fixing seat; the hand Providing at least one first oil return hole connected to the oil storage space at the reciprocating motion of the main cylinder for the first O-ring; the sleeve is provided with at least one second connection connected to the oil storage space An oil hole; a spring is disposed at a position between the main cylinder of the handle and the piston; the handle is formed at a position where the main oil cylinder is opposite to the first oil return hole, and an inner diameter is relatively larger than the first An oil return section of the outer diameter of the O-ring: the piston is between the first O-ring and the second O-ring There is a counter at the constriction Segment: the piston is provided with a ball seat opposite to one end of the fixed seat, the pull rod is provided with a ball end that is sleeved with the ball seat; the pull rod is pivotally connected to the mounted handlebar through a rotating shaft; The rod body of the drawbar is provided with a threaded section, and the rotating shaft is provided with a screw hole for screwing with the threaded section of the pull rod.