Brake upper pump with clutch type double-stroke piston

Abstract

A brake upper pump with a clutch type double-stroke piston comprises a brake pump body which is provided with a piston cavity and an oil storage cavity; the brake handle is in running fit with the brake pump body through a pivoting mechanism; the oil pipe assembly is communicated with the piston cavity; the piston push rod assembly comprises a first piston, a second piston and a reset spring; the piston cavity is provided with a large-diameter cavity section, a small-diameter cavity section and a variable-diameter cavity section; the first piston is sleeved with a first oil seal, the second piston is sleeved with a second oil seal, and the radial size of the first oil seal is larger than that of the second oil seal. The first oil seal moves along with the first piston, and the first oil seal is in sealing fit with the inner wall of the large-diameter cavity section. The second oil seal moves along with the second piston, the second oil seal is in non-sealing fit with the inner wall of the large-diameter cavity section, and the second oil seal is in sealing fit with the inner wall of the small-diameter cavity section. The first oil seal and the second oil seal have different displacement expressions in each use stage, and the braking effect is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic brake, in particular to a brake upper pump with clutch type double-stroke piston. BACKGROUND

[0002] Brake, an important part of vehicle safety, the quality of the brake often related to the life safety of the rider, especially for the riders who often need to be in high-speed competition, if the structure and efficiency of the brake are not perfect enough, even if the rider's driving skills are high, it is also impossible to control the bicycle at will, especially at high speed, the impulse and kinetic energy reach the highest value, if the brake cannot be smoothly performed, the life of oneself or others cannot be guaranteed, and it may cause large-scale disaster.

[0003] In the traditional installation process of brake wire of electric vehicles, bicycles, tricycles and other vehicles, steel wire pliers, wrenches and other traditional tools are generally used to tighten with brute force. This traditional steel wire tightening method has many shortcomings and is difficult to operate. For example: the steel wire is easy to slip out of the steel wire pliers or wrench, and it is not easy to adjust the tightness, especially time-consuming and laborious. In order to pursue brake efficiency and accuracy, oil pressure type brakes are widely used in current market tools (such as motor vehicles and bicycles), the principle of which is that one end of a brake oil pipe is combined with the output end of the internal oil way of a brake handle seat, and the other end of the brake oil pipe is combined with a disc brake, which can be pushed by the pressing of the handle to make the oil way inside the oil way. The pressure acts on the disc brake through the brake oil pipe, and the operation of the disc brake is formed.

[0004] As patent document CN100503354C, discloses a bicycle to improve the difference between the front and rear wheel brake actuation of oil pressure disc brake, including a frame, a handle, a front wheel unit, a rear wheel unit, a rear wheel oil pressure handle, a rear wheel disc brake, a rear wheel oil pressure clamp brake device, a rear wheel oil pressure pipe connected between the rear wheel oil pressure handle and the rear wheel oil pressure clamp brake device and having a first inner pipe diameter, and a front wheel oil pressure disc brake unit having a front wheel oil pressure handle, a front wheel disc brake, a front wheel oil pressure clamp brake device, a front wheel oil pressure pipe connected between the front wheel oil pressure handle and the front wheel oil pressure clamp brake device and having a second inner pipe diameter greater than the first inner pipe diameter. When the front and rear wheel oil pressure handles are switched from a release state to a tight state, the front and rear wheel oil pressure clamp brake devices are forced to switch from a release state to a brake state, and the front and rear wheel disc brake pads are clamped at nearly the same time. As described in the above patent, the working principle of the oil brake adopts Pascal's principle. Pascal's principle refers to the pressure acting on a closed fluid that can be transmitted to each part of the container without changing the size. It has the following characteristics: 1. The law is only applicable to fluid mechanics. Because the liquid is flowing, when it is placed in a sealed container, its pressure changes and it will spread the pressure in all directions. The force does not change during transmission. 2. Pascal's law is a basic principle of hydrostatics. Pascal's law shows that in an incompressible static liquid, any point under pressure will be transmitted to the static liquid instantaneously. 3. According to Pascal's law, when pressure acts on a certain piston, it will inevitably cause the same pressure on the other piston. If the area of the second piston is one tenth of the first piston, the pressure applied to the first piston will increase ten times the pressure of the second piston. 4. The basic formula of Pascal's law is: P = F1 / S1 = F2 / S2, i.e. F2 = (S2 / S1)F1.

[0005] Therefore, in the case of selecting the same brake pad piston, if the cross-sectional area of the piston rod (piston oil seal) used is larger, on the one hand, according to Pascal's principle, the pressure acting on the brake pad piston is smaller, resulting in smaller holding force of the brake disc, and the brake effect is poorer; on the other hand, more oil is pushed out per unit distance, and the displacement of the brake pad is larger, so the distance between the brake disc and the brake pad is farther in the initial setting, and the disc clamping phenomenon does not occur. If the cross-sectional area of the piston rod (piston oil seal) used is smaller, on the one hand, according to Pascal's principle, the pressure acting on the brake pad piston is larger, i.e. the pressure generated on the brake pad piston is larger, resulting in larger holding force of the brake disc, and the brake effect is better; on the other hand, less oil is pushed out per unit distance, and the displacement of the brake pad is smaller, so the distance between the brake disc and the brake pad is closer in the initial setting, and the disc clamping phenomenon occurs (i.e. contact friction exists even without using the brake).

[0006] Therefore, it is necessary to further improve the existing brake products. SUMMARY

[0007] In order to overcome the above-mentioned deficiencies of the prior art, the present application provides a brake upper pump with a clutch type double-stroke piston.

[0008] The technical scheme for solving the technical problems of the present application is: a brake upper pump with a clutch type double-stroke piston, a brake pump body, which is provided with a piston cavity and an oil storage cavity, the piston cavity and the oil storage cavity are filled with brake oil, and the oil storage cavity is in communication with the piston cavity through an oil supplementing hole;

[0009] A brake handle is rotatably connected to the brake pump body through a pivoting mechanism;

[0010] An oil pipe assembly is connected to the brake pump body and in communication with the piston cavity;

[0011] A piston push rod assembly includes a first piston and a second piston, and a return spring, the first piston is movably arranged in the piston cavity and is in driving connection with the brake handle through a rotating and pushing mechanism, the second piston is movably arranged in the piston cavity and is located at the front end of the first piston, and the return spring acts on the second piston to make the second piston and the first piston always have a backward movement tendency;

[0012] The piston cavity has at least a large-diameter cavity section, a small-diameter cavity section, and a variable-diameter cavity section between the large-diameter cavity section and the small-diameter cavity section, the junction of the large-diameter cavity section and the variable-diameter cavity section is a first critical point, and the junction of the variable-diameter cavity section and the small-diameter cavity section is a second critical point;

[0013] A first oil seal is arranged on the first piston, and a second oil seal is arranged on the second piston, the radial dimension of the first oil seal is greater than the radial dimension of the large-diameter cavity, the radial dimension of the second oil seal is greater than the radial dimension of the small-diameter cavity and smaller than the radial dimension of the large-diameter cavity, and the radial dimension of the first oil seal is greater than the radial dimension of the second oil seal;

[0014] The first oil seal moves with the first piston, and the first oil seal forms a sealing fit with the inner wall of the large-diameter cavity section when the first oil seal abuts against the inner wall;

[0015] The second oil seal moves with the second piston, when the second oil seal is located in the large-diameter cavity section, there is a gap between the second oil seal and the inner wall of the large-diameter cavity section to form a non-sealing fit, and when the second oil seal is located in the small-diameter cavity section, the second oil seal abuts against the inner wall of the small-diameter cavity section to form a sealing fit.

[0016] Optionally, when the second oil seal is located at the latter part of the variable-diameter cavity section, a gap exists between the second oil seal and the inner wall of the variable-diameter cavity section to form a non-sealing fit; when the second oil seal is located at the former part of the variable-diameter cavity section, the second oil seal abuts against the inner wall of the variable-diameter cavity section to form a sealing fit.

[0017] In a preferred embodiment of the present application, a boost flow channel is formed on the second piston and / or the first piston, and the boost flow channel is in communication with the piston cavity.

[0018] When the first oil seal passes through the oil supplement hole and abuts against the inner wall of the large-diameter cavity section, and the second oil seal abuts against the inner wall of the variable-diameter cavity section / small-diameter cavity section, a closed oil seal cavity is formed between the first oil seal and the second oil seal.

[0019] At this time, the first oil seal and the second oil seal continue to push oil forward, respectively, the displacement of the rotation and push mechanism is L, the oil pushing amount of the first oil seal is Q1, the oil pushing amount of the second oil seal is Q2, and Q1>Q2 is satisfied, the difference ΔQ between the oil pushing amounts of the first oil seal and the second oil seal is Q1-Q2, therefore, the brake oil of ΔQ flows into the boost flow channel, and the boost force of the brake oil of ΔQ in the boost flow channel is applied to the second piston to move forward, so that the second piston has a larger forward displacement ΔL relative to the first piston.

[0020] The displacement of the first piston is L1=L, and the displacement of the second piston is L2=L+ΔL.

[0021] It should be noted that the boost force of the brake oil of ΔQ in the boost flow channel applied to the second piston to move forward is F1, and the boost force of the reset spring acting on the second piston is F2.

[0022] When F1>F2, the boost force F1 makes the second piston have a larger forward displacement ΔL relative to the first piston.

[0023] It should be noted that the effective sealing area of the first oil seal is S1, the effective sealing area of the second oil seal is S2, and ΔQ=(S1-S2)×L.

[0024] The volume of the boost flow channel is ΔV, and the effective boost area of the boost flow channel and the second piston is S3, ΔV=S3×ΔL.

[0025] When the closed oil seal cavity is formed between the first oil seal and the second oil seal, the brake oil of ΔQ all flows into the boost flow channel, so that ΔV=ΔQ in this process, that is, S3×ΔL=(S1-S2)×L, and ΔL=((S1-S2)×L) / S3 is obtained.

[0026] Preferably, the first piston is provided with a guide slot, the rear end of the second piston extends into the guide slot, the second piston can move relative to the guide slot, and the boost channel is in communication with the guide slot.

[0027] It is worth mentioning that the second piston and the first piston form at least an engaging position state and a separation position state relative to each other.

[0028] When the second piston and the first piston are in the engaging position state, the second piston abuts against the first piston, at this time, the brake handle is pinched, and the second piston and the first piston move forward synchronously.

[0029] When the second piston and the first piston are in the separation position state, the second piston is separated from the first piston, at this time, the brake handle is pinched, and the second piston and the first piston move forward asynchronously.

[0030] In the preferred embodiment of the present application, the front end of the first piston is provided with a driving end face, the second piston is provided with a force receiving part, when the driving end face abuts against the force receiving part, the second piston and the first piston are in the engaging position state, and when the driving end face is separated from the force receiving part, the second piston and the first piston are in the separation position state.

[0031] In the preferred embodiment of the present application, the first piston is provided with a first oil seal groove, and the first oil seal is embedded in the first oil seal groove, so that the first oil seal moves synchronously with the first piston.

[0032] The second piston is provided with a second oil seal groove, and the second oil seal is embedded in the second oil seal groove, so that the second oil seal moves synchronously with the second piston.

[0033] In the preferred embodiment of the present application, the piston push rod assembly further comprises a piston sleeve, the piston sleeve is arranged in the piston cavity, and the piston sleeve is provided with a driving hole.

[0034] The rotating and pushing mechanism at least partially extends into the driving hole from the rear to the front, the first piston at least partially extends into the driving hole from the front to the rear, and the front end of the rotating mechanism abuts against the rear end of the first piston and forms a transmission cooperation.

[0035] An inner sealing ring is arranged between the outer wall of the first piston and the inner wall of the piston sleeve, and an outer sealing ring is arranged between the outer wall of the piston sleeve and the inner wall of the piston cavity.

[0036] The present application has the following beneficial effects:

[0037] I. The first piston (first oil seal) and the second piston (second oil seal) have different displacement amounts in each use stage: the first stage of pinching the brake handle, the oil path between the piston cavity in front of the first oil seal and the brake lower pump is closed, at this time pinching the brake handle does not have the brake effect. The second stage of pinching the brake handle, the oil path between the piston cavity in front of the first oil seal and the brake lower pump is closed, at this time pinching the brake handle will push brake oil to the brake lower pump by the first oil seal, and more brake oil can be pushed out under the same displacement amount, so that faster brake response can be obtained in this stage, and good braking effect is achieved. The third stage of pinching the brake handle, the pushing oil amount of the first oil seal is greater than that of the second oil seal, the excess pushing oil amount will enter the gap between the first piston and the second piston and apply a boost force (provided by brake oil) to the second piston to separate the second piston from the first piston, and the second piston has a greater forward displacement amount relative to the first piston, so that the user can push more brake oil to the brake lower pump with less force in the later stage of pinching the brake handle, thereby achieving more obvious braking effect, and because the effective sealing area of the second oil seal is smaller, the user feels weaker wall collision when pinching the brake handle, thereby having a more linear hand feeling in the entire brake process.

[0038] II. The greater the pinching amount of the brake handle in the third stage, the more pushing oil amount of the first oil seal than the second oil seal, so the separation distance between the second piston and the first piston is greater, and the displacement amount of the second piston (second oil seal) is greater, thereby achieving more obvious braking effect.

[0039] III. Having a variable force arm fulcrum: in each use stage, the force arm performance is different, specifically: in the second stage, the fulcrums of the power arm and the resistance arm are the same, both located at the first oil seal, at this time the force required to pinch the brake handle is consistent with that of the conventional single-piston brake upper pump; the difference is that in the third stage, the fulcrum of the power arm is still at the first oil seal, and the fulcrum of the resistance arm is switched to the second oil seal, so compared with the prior art (the fulcrums of the power arm and the resistance arm are at the same position), the user pinches the brake handle with less force under the condition of outputting the same brake force to the brake lower pump, that is, in the third stage, more energy-saving is achieved under the condition of obtaining the same brake effect. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structural schematic diagram of the present application.

[0041] Figure 2 is a split schematic diagram of the present application.

[0042] Figure 3 is an exploded view of the piston push rod assembly.

[0043] Figure 4 is a structural schematic diagram of the first piston and the second piston,

[0044] Figure 5 is a partial structure sectional view of the brake pump body.

[0045] Figure 6 is a contrast schematic view of the second piston and the first piston in the engaged position state and the separated position state.

[0046] Figure 7 is a vertical sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the first stage).

[0047] Figure 8 is a horizontal sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the first stage).

[0048] Figure 9 is a vertical sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the second stage).

[0049] Figure 10 is a horizontal sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the second stage).

[0050] Figure 11 is a vertical sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the third stage).

[0051] Figure 12 is a horizontal sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the third stage).

[0052] Figure 13 is another position vertical sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the third stage).

[0053] Figure 14 is another position horizontal sectional view and a partial structure enlarged schematic view of the present invention (the piston push rod assembly displacement amount is in the third stage).

[0054] In the figure: 1, brake pump body; 11, piston cavity; 111, large diameter cavity section; 12a, first critical point; 112, variable diameter cavity section; 23a, second critical point; 113, small diameter cavity section; 12, oil storage cavity; 123, oil supplement hole; 13, oil seal cavity; 14, connecting hole; 2, brake handle; 21, pivoting mechanism; 22, rotating pushing mechanism; 3, oil pipe assembly; 4, piston push rod assembly; 412a, engagement position state; 412b, separation position state; 41, first piston; 411, guide groove; 412, driving end face; 413, first oil seal groove; 42, second piston; 421, boost flow channel; 422, force receiving part; 423, second oil seal groove; 43, return spring; 44, first oil seal; 45, second oil seal; 4a, sealing fit; 4b, non-sealing fit; 46, piston cylinder sleeve; 461, driving hole; 462, fastener; 463, limiting groove; 6, inner sealing ring; 7, outer sealing ring. DETAILED DESCRIPTION

[0055] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0056] REFERENCE Figures 1-14The utility model provides a brake pump with clutch type double stroke piston, brake pump body 1 is provided with piston cavity 11 and oil storage cavity 12, piston cavity 11 and oil storage cavity 12 are filled with brake oil, and oil storage cavity 12 is communicated with piston cavity 11 through oil supplementing hole 123, brake handle 2 is rotatably connected with brake pump body 1 through pivot mechanism 21, oil pipe assembly 3 is connected to brake pump body 1 and is communicated with piston cavity 11, piston push rod assembly 4 includes first piston 41 and second piston 42, reset spring 43, first piston 41 is movably arranged in piston cavity 11, and first piston 41 is connected with brake handle 2 through rotation push mechanism 22, second piston 42 is movably arranged in piston cavity 11, and second piston 42 is located at the front end of first piston 41, reset spring 43 acts on second piston 42, so that second piston 42 and first piston 41 always have the movement tendency of moving back (if second piston 42 retreats, second piston 42 reengages with first piston 41 and makes first piston 41 also retreat under the elastic force of reset spring 43). It needs to be particularly emphasized that first piston 41 and second piston 42 do not have fixed relationship, so second piston 42 and first piston 41 can realize relative displacement. On the other hand, it should be understood that first piston 41 always has the same forward displacement with rotation push mechanism 22, when the initial section of brake handle 2 is pinched, second piston 42 and first piston 41 are engaged (abut) at this time, and second piston 42 and first piston 41 (rotation push mechanism 22) have the same forward displacement, when the middle and rear section of brake handle 2 is pinched, second piston 42 and first piston 41 are separated at this time, and second piston 42 and first piston 41 (rotation push mechanism 22) have different forward displacements.

[0057] The prior art generally only has a single piston, and the utility model has at least two pistons (first piston 41 and second piston 42), and in order to adapt to the function of the multi-piston structure, the specific structure also includes:

[0058] I. Refer to Figure 5 Piston cavity 11 has at least large-diameter cavity section 111, small-diameter cavity section 113 and variable-diameter cavity section 112 between large-diameter cavity section 111 and small-diameter cavity section 113, the junction of large-diameter cavity section 111 and variable-diameter cavity section 112 is first critical point 12a, and the junction of variable-diameter cavity section 112 and small-diameter cavity section 113 is second critical point 23a, and the radial dimension of variable-diameter cavity section 112 gradually decreases from the rear (first critical point 12a) to the front (second critical point 23a) to realize the structure transition.

[0059] II. Refer to Figure 3 , Figure 4 , Figure 6The first piston 41 is sleeved with a first oil seal 44, and the second piston 42 is sleeved with a second oil seal 45. More specifically, the radial dimension of the first oil seal 44 is greater than the radial dimension of the large-diameter cavity, the radial dimension of the second oil seal 45 is greater than the radial dimension of the small-diameter cavity and less than the radial dimension of the large-diameter cavity, and the radial dimension of the first oil seal 44 is greater than the radial dimension of the second oil seal 45. It should be noted that the oil seal with a larger radial dimension can push out more brake oil under the same displacement.

[0060] It should be noted that the first oil seal 44 and the second oil seal 45 can also be replaced by other sealing elements, and the first oil seal 44 can be integrally formed with the first piston 41 (using materials such as rubber), or can be formed in separate parts. The second oil seal 45 can be integrally formed with the second piston 42 (using materials such as rubber), or can be formed in separate parts, which is not specifically limited here.

[0061] Regarding the first oil seal 44, the first oil seal 44 moves with the first piston 41, and the first oil seal 44 forms a sealing fit 4a when it abuts against the inner wall of the large-diameter cavity section 111. Therefore, during the movement of the first piston 41, the first oil seal 44 always has the effect of pushing oil forward.

[0062] Regarding the second oil seal 45, the second oil seal 45 moves with the second piston 42. When the second oil seal 45 is located in the large-diameter cavity section 111, there is a gap between the second oil seal 45 and the inner wall of the large-diameter cavity section 111 to form a non-sealing fit 4b. During the movement of the second piston 42 at this stage, the second oil seal 45 does not have the effect of pushing oil forward. When the second oil seal 45 is located in the small-diameter cavity section 113, the second oil seal 45 abuts against the inner wall of the small-diameter cavity section 113 and forms a sealing fit 4a. During the movement of the second piston 42 at this stage, the second oil seal 45 has the effect of pushing oil forward.

[0063] The function of the oil seal is consistent with that in the prior art, and it can seal and prevent leakage when the piston is pushed forward, so as to push the brake oil out of the brake pump. The difference is that the present application has a double oil seal structure to adapt to the double piston structure scheme.

[0064] The above is the basic structure scheme of the present application. According to the order of displacement of the piston push rod assembly 4 from small to large, the unique performance brought by the distinguishing features is at least:

[0065] First stage: refer to Figures 7-8, the first oil seal 44 is not through the oil supplement hole 123, and the piston cavity 11 in front of the first oil seal 44 is kept in communication with the oil storage cavity 12, that is, the oil passage between the piston cavity 11 in front of the first oil seal 44 and the brake lower pump is not closed, and at this time the brake handle 2 does not have a brake effect.

[0066] The second stage: refer to Figures 9-10 , continue to pinch the brake handle 2, the first oil seal 44 passes through the oil supplement hole 123 and the second oil seal 45 has not yet abuts with the inner wall of the piston cavity 11 (small diameter cavity section 113), and after the piston push rod assembly 4 completes the empty stroke (free stroke), the piston cavity 11 in front of the first oil seal 44 is disconnected with the oil storage cavity 12, that is, the oil passage between the piston cavity 11 in front of the first oil seal 44 and the brake lower pump is closed, and at this time pinching the brake handle 2 will push brake oil to the brake lower pump by the first oil seal 44 and have a brake effect.

[0067] The third stage: refer to Figures 11-12 , continue to pinch the brake handle 2, the second oil seal 45 abuts with the inner wall of the small diameter cavity section 113 and forms a sealing fit 4a, at this time the oil passage between the piston cavity 11 in front of the second oil seal 45 and the brake lower pump is closed, and pinching the brake handle 2 will push brake oil to the brake lower pump by the second oil seal 45 and have a brake effect.

[0068] It needs to be further clarified that in the third stage, a relatively closed oil seal cavity 13 has been formed between the first oil seal 44 and the second oil seal 45, that is, the brake oil between the first oil seal 44 and the second oil seal 45 cannot flow to the front side of the second oil seal 45. Based on the aforementioned oil pushing amount principle (under the same movement amount, the brake oil pushed forward has a larger oil amount), therefore, the oil pushing amount of the first oil seal 44 is greater than that of the second oil seal 45. And the brake oil is a liquid, and under the working condition of pinching the brake handle 2, the liquid compression of the brake oil itself can be ignored, therefore, the excess oil pushing amount of the first oil seal 44 will enter the gap between the first piston 41 and the second piston 42 and apply a forward thrust (provided by the brake oil) to the second piston 42 to separate the second piston 42 from the first piston 41, and the second piston 42 has a greater forward displacement relative to the first piston 41. On the other hand, refer to Figures 13-14 , the greater the amount of pinching the brake handle 2 in the third stage, the more the excess oil pushing amount of the first oil seal 44 than the second oil seal 45, and therefore the separation distance between the second piston 42 and the first piston 41 is greater.

[0069] From another perspective, the force arm performance of the present application is different in each use stage, specifically: in the second stage, the fulcrum of the power arm and the resistance arm are the same, both located at the first oil seal 44, at this time the force required to pinch the brake handle 2 is consistent with the force of the conventional single-piston brake pump; the difference is that in the third stage, the fulcrum of the power arm is still at the first oil seal 44, and the fulcrum of the resistance arm is switched to the second oil seal 45, so compared with the prior art (the fulcrums of the power arm and the resistance arm are at the same position), in the case of outputting to the brake pump to obtain the same brake force, the user pinches the brake handle 2 with less force, that is, in the third stage, it is more labor-saving to obtain the same brake effect.

[0070] Regarding the relationship between the first piston 41 and the second piston 42 in each stage, the specific explanation is as follows: Figure 6 , the second piston 42 and the first piston 41 form at least an engaged position state 412a and a separated position state 412b with each other; when the second piston 42 and the first piston 41 are in the engaged position state 412a, the second piston 42 abuts against the first piston 41, at this time pinching the brake handle 2, the second piston 42 and the first piston 41 move forward synchronously; when the second piston 42 and the first piston 41 are in the separated position state 412b, the second piston 42 is separated from the first piston 41, at this time pinching the brake handle 2, the second piston 42 and the first piston 41 move forward asynchronously.

[0071] Embodiment Two

[0072] In this embodiment, as a further supplement to the structure of Embodiment One, referring to Figures 11-12 , when the second oil seal 45 is located at the rear part of the variable-diameter cavity section 112, there is a gap between the second oil seal 45 and the inner wall of the variable-diameter cavity section 112 to form a non-sealing fit 4b; when the second oil seal 45 is located at the front part of the variable-diameter cavity section 112, the second oil seal 45 abuts against the inner wall of the variable-diameter cavity section 112 and forms a sealing fit 4a.

[0073] Through the cooperation of the second oil seal 45 and the variable-diameter cavity section 112, the second stage can be ended early and the third stage can be started early. The specific size is determined according to the variable-diameter cavity section 112, the small-diameter cavity section 113 and the second oil seal 45, which is not specially limited here.

[0074] Embodiment Three

[0075] On the basis of any structure of Embodiment One and Embodiment Two, this embodiment provides more detailed structural explanations, as follows:

[0076] I. Referring to Figure 4 , Figure 8 , Figure 10 ,Figure 12 、 Figure 14 The second piston 42 and / or the first piston 41 are provided with a boosting channel 421, which is in communication with the piston chamber 11. That is, in the third stage, the excess oil produced by the first oil seal 44 relative to the second oil seal 45 will flow through the boosting channel 421 into the gap between the first piston 41 and the second piston 42, applying a forward boosting force (provided by the brake fluid) to the second piston 42. The specific operating principle is as follows:

[0077] Reference Figure 11 、 Figure 13 When the first oil seal 44 passes through the oil replenishing hole 123 and abuts against the inner wall of the large-diameter cavity section 111, and the second oil seal 45 abuts against the inner wall of the variable-diameter cavity section 112 / small-diameter cavity section 113, a closed oil seal cavity 13 is formed between the first oil seal 44 and the second oil seal 45. At this time, the brake handle 2 continues to be squeezed, and the first oil seal 44 and the second oil seal 45 push oil forward respectively. The displacement of the push-pushing mechanism 22 is L, the oil pushing amount of the first oil seal 44 is Q1, and the oil pushing amount of the second oil seal 45 is Q2, and Q1>Q2 is satisfied. The difference in the oil pushing amount between the first oil seal 44 and the second oil seal 45 is △Q=Q1-Q2. Therefore, △Q of brake oil flows into the boosting channel 421, and the △Q of brake oil in the boosting channel 421 applies a forward boosting force to the second piston 42, so that the second piston 42 has a larger forward displacement △L relative to the first piston 41.

[0078] The displacement of the first piston 41 is L1 = L, and the displacement of the second piston 42 is L2 = L + ΔL. In other words, when the brake handle 2 is squeezed in the third stage, the second piston 42 will achieve a greater displacement than the first piston 41, and the second oil seal 45 will also achieve a greater displacement than the first oil seal 44. This allows the user to achieve greater braking force with less force in the third stage, while also reducing the feeling of hitting the wall.

[0079] Second, it should be noted that the brake fluid ΔQ in the boosting channel 421 applies a forward boosting force F1 to the second piston 42, and the boosting force F2 to the second piston 42 by the return spring 43 is F2. When F1>F2, the boosting force F1 causes the second piston 42 to have a greater forward displacement ΔL relative to the first piston 41. If F2>F1, the second piston 42 cannot be separated from the first piston 41; the two remain in contact, thereby maintaining synchronous motion.

[0080] 3. It should be noted that, with reference to Figure 12 、 Figure 14In the third stage, the second piston 42 has more displacement amount relative to the first piston 41, and is also associated with the effective sealing area of the first oil seal 44 and the second oil seal 45. Specifically, the effective sealing area of the first oil seal 44 is S1, the effective sealing area of the second oil seal 45 is S2, and ΔQ=(S1-S2)×L; the volume of the boost flow channel 421 is ΔV, and the effective boost area of the boost flow channel 421 and the second piston 42 is S3, ΔV=S3×ΔL; when the closed oil seal cavity 13 is formed between the first oil seal 44 and the second oil seal 45, all of the brake oil of ΔQ flows into the boost flow channel 421, so that ΔV=ΔQ in this process, that is, S3×ΔL=(S1-S2)×L, and ΔL=((S1-S2)×L) / S3 is obtained.

[0081] Embodiment Four

[0082] On the basis of any of the preceding embodiments, the present embodiment provides a more preferred structural scheme, specifically:

[0083] I. Preferred guide structure of the first piston 41 and the second piston 42: refer to Figure 4 , Figures 7-14 The first piston 41 is provided with a guide groove 411, the rear end of the second piston 42 extends into the guide groove 411, the second piston 42 can move relative to the guide groove 411, and the boost flow channel 421 is in communication with the guide groove 411. The guide groove 411 is provided, which can play a guiding role for the second piston 42 to prevent the second piston 42 from deviating from its normal movement path; secondly, in the present embodiment, the guide groove 411 can also be understood as belonging to a part of the boost flow channel 421, which can be used to accommodate the excess oil pushing amount of the first oil seal 44 than the second oil seal 45.

[0084] II. Preferred transmission structure of the first piston 41 and the second piston 42: refer to Figure 4 , Figures 7-14 The front end of the first piston 41 has a driving end face 412, the second piston 42 has a force receiving portion 422, when the driving end face 412 abuts against the force receiving portion 422, the second piston 42 and the first piston 41 are in the engaged position state 412a; when the driving end face 412 is separated from the force receiving portion 422, the second piston 42 and the first piston 41 are in the separated position state 412b. The cooperation of the driving end face 412 and the force receiving portion 422 can make the first piston 41 and the second piston 42 have more stable contact effect and movement performance when abutting.

[0085] III. Preferred assembly structure of the first oil seal 44 and the second oil seal 45: refer to Figure 4 , Figure 6The first piston 41 is provided with a first oil seal 44 slot 413, and the first oil seal 44 is embedded in the first oil seal 44 slot 413, so that the first oil seal 44 moves synchronously with the first piston 41; the second piston 42 is provided with a second oil seal 45 slot 423, and the second oil seal 45 is embedded in the second oil seal 45 slot 423, so that the second oil seal 45 moves synchronously with the second piston 42.

[0086] Four, a more preferred structure of the piston push rod assembly 4: refer to Figure 3 、 Figures 7-14 The piston push rod assembly 4 further comprises a piston sleeve 46, the piston sleeve 46 is arranged in the piston cavity 11, and the piston sleeve 46 has a driving hole 461; the rotation and push mechanism 22 at least partially extends into the driving hole 461 from back to front, the first piston 41 at least partially extends into the driving hole 461 from front to back, and the front end of the rotation mechanism abuts against the rear end of the first piston 41 and forms a transmission fit. Through the arrangement of the piston sleeve 46, on the one hand, the first piston 41 and the second piston 42 can be protected; on the other hand, it is convenient for disassembly and maintenance in the later period.

[0087] Further, refer to Figure 7 、 Figure 9 、 Figure 11 The brake pump body 1 is provided with a connecting hole 14 (preferably a threaded fit), the piston sleeve 46 is provided with a limiting slot 463, and the fastener 462 extends into the limiting slot 463 from the side through the connecting hole 14, so as to realize the connection between the piston sleeve 46 and the brake pump body 1.

[0088] Five, a preferred sealing structure of the piston push rod assembly 4: refer to Figure 3 、 Figure 6 、 Figure 7 、 Figure 9 、 Figure 11 、 Figure 13 An inner sealing ring 6 is arranged between the outer wall of the first piston 41 and the inner wall of the piston sleeve 46, and an outer sealing ring 7 is arranged between the outer wall of the piston sleeve 46 and the inner wall of the piston cavity 11. Through the arrangement of the inner sealing ring 6 and the outer sealing ring 7, a double sealing effect is achieved, which can better reduce the probability of oil seepage and leakage of the piston push rod assembly 4 during use.

[0089] The above is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent structural change made according to the technical essence of the present application to the above embodiment are still within the protection scope of the technical solution of the present application.

Claims

1. A brake on-pump with clutch type double stroke piston, the brake pump body (1) is provided with a piston cavity (11) and an oil storage cavity (12), the piston cavity (11) and the oil storage cavity (12) are filled with brake oil, and the oil storage cavity (12) is communicated with the piston cavity (11) through an oil supplement hole (123); a brake handle (2) is rotatably connected with the brake pump body (1) through a pivot mechanism (21); an oil pipe assembly (3) is connected to the brake pump body (1) and communicated with the piston cavity (11); a piston push rod assembly (4) comprises a first piston (41), a second piston (42) and a return spring (43), the first piston (41) is movably arranged in the piston cavity (11), and the first piston (41) is drivingly connected with the brake handle (2) through a rotation and push mechanism (22); the second piston (42) is movably arranged in the piston cavity (11), and the second piston (42) is located at the front end of the first piston (41); the return spring (43) acts on the second piston (42) to make the second piston (42) and the first piston (41) always have a backward movement trend; characterized in that the piston cavity (11) has at least a large-diameter cavity section (111), a small-diameter cavity section (113) and a variable-diameter cavity section (112) between the large-diameter cavity section (111) and the small-diameter cavity section (113), the junction of the large-diameter cavity section (111) and the variable-diameter cavity section (112) is a first critical point (12a), and the junction of the variable-diameter cavity section (112) and the small-diameter cavity section (113) is a second critical point (23a); a first oil seal (44) is sleeved on the first piston (41), and a second oil seal (45) is sleeved on the second piston (42); the radial dimension of the first oil seal (44) is greater than the radial dimension of the large-diameter cavity, the radial dimension of the second oil seal (45) is greater than the radial dimension of the small-diameter cavity and less than the radial dimension of the large-diameter cavity, and the radial dimension of the first oil seal (44) is greater than the radial dimension of the second oil seal (45); the first oil seal (44) moves with the first piston (41), and the first oil seal (44) forms a sealing fit (4a) with the inner wall of the large-diameter cavity section (111) when the first oil seal (44) abuts against the inner wall of the large-diameter cavity section (111); the second oil seal (45) moves with the second piston (42); when the second oil seal (45) is located in the large-diameter cavity section (111), there is a gap between the second oil seal (45) and the inner wall of the large-diameter cavity section (111) to form a non-sealing fit (4b); when the second oil seal (45) is located in the small-diameter cavity section (113), the second oil seal (45) abuts against the inner wall of the small-diameter cavity section (113) and forms a sealing fit (4a).

2. The brake apply pump with clutching bi-stroke piston of claim 1 wherein: When the second oil seal (45) is located at the rear part of the variable-diameter cavity section (112), a gap exists between the second oil seal (45) and the inner wall of the variable-diameter cavity section (112) to form a non-sealing fit (4b); when the second oil seal (45) is located at the front part of the variable-diameter cavity section (112), the second oil seal (45) abuts against the inner wall of the variable-diameter cavity section (112) to form a sealing fit (4a).

3. A brake apply pump having a clutching double stroke piston according to claim 1 or 2, characterized in that: The second piston (42) or / and the first piston (41) is provided with a boost flow channel (421) which is in communication with the piston cavity (11); When the first oil seal (44) passes through the oil supplement hole (123) and abuts against the inner wall of the large-diameter cavity section (111), and the second oil seal (45) abuts against the inner wall of the variable-diameter cavity section (112) / small-diameter cavity section (113), an enclosed oil seal cavity (13) is formed between the first oil seal (44) and the second oil seal (45); At this time, the first oil seal (44) and the second oil seal (45) continue to push oil forward, the displacement of the rotation and push mechanism (22) is L, the oil pushing amount of the first oil seal (44) is Q1, the oil pushing amount of the second oil seal (45) is Q2, and Q1>Q2 is satisfied, the difference ΔQ between the oil pushing amounts of the first oil seal (44) and the second oil seal (45) is Q1-Q2, therefore the brake oil of ΔQ flows into the boost flow channel (421), and the boost force of the brake oil of ΔQ in the boost flow channel (421) is applied to the second piston (42) to move forward, so that the second piston (42) has a larger forward displacement ΔL relative to the first piston (41); The displacement of the first piston (41) is L1=L, and the displacement of the second piston (42) is L2=L+ΔL.

4. The brake apply pump with clutching bi-stroke piston of claim 3 wherein: The boost force of the brake oil of ΔQ in the boost flow channel (421) is F1, and the boost force of the reset spring (43) acting on the second piston (42) is F2; When F1>F2, the boost force F1 makes the second piston (42) have a larger forward displacement ΔL relative to the first piston (41).

5. The brake apply pump with clutching bi-stroke piston of claim 4 wherein: The effective sealing area of the first oil seal (44) is S1, the effective sealing area of the second oil seal (45) is S2, and ΔQ=(S1-S2)×L; The volume of the boost flow channel (421) is ΔV, and the effective boost area of the boost flow channel (421) and the second piston (42) is S3, ΔV=S3×ΔL; When the enclosed oil seal cavity (13) is formed between the first oil seal (44) and the second oil seal (45), all the brake oil of ΔQ flows into the boost flow channel (421), so that ΔV=ΔQ in this process, that is, S3×ΔL=(S1-S2)×L, and ΔL=((S1-S2)×L) / S3 is obtained.

6. The brake apply pump with clutching bi-stroke piston of claim 3 wherein: The first piston (41) is provided with a guide groove (411), the rear end of the second piston (42) extends into the guide groove (411), the second piston (42) can move relative to the guide groove (411), and the boost channel (421) is communicated with the guide groove (411).

7. The brake apply pump with clutching bi-stroke piston of claim 1 or 2, wherein: The second piston (42) and the first piston (41) form at least an engaging position state (412a) and a separation position state (412b) relative to each other; When the second piston (42) and the first piston (41) are in the engaging position state (412a), the second piston (42) abuts against the first piston (41), at this time, the brake handle (2) is pinched, and the second piston (42) and the first piston (41) move forward synchronously; When the second piston (42) and the first piston (41) are in the separation position state (412b), the second piston (42) is separated from the first piston (41), at this time, the brake handle (2) is pinched, and the second piston (42) and the first piston (41) move forward asynchronously.

8. The brake apply pump with clutching bi-stroke piston of claim 7 wherein: The front end of the first piston (41) is provided with a driving end face (412), the second piston (42) is provided with a force receiving part (422), when the driving end face (412) abuts against the force receiving part (422), the second piston (42) and the first piston (41) are in the engaging position state (412a), and when the driving end face (412) is separated from the force receiving part (422), the second piston (42) and the first piston (41) are in the separation position state (412b).

9. The brake apply pump with clutching bi-stroke piston of claim 1 wherein: The first piston (41) is provided with a first oil seal (44) groove (413), and the first oil seal (44) is embedded in the first oil seal (44) groove (413), so that the first oil seal (44) moves synchronously with the first piston (41); The second piston (42) is provided with a second oil seal (45) groove (423), and the second oil seal (45) is embedded in the second oil seal (45) groove (423), so that the second oil seal (45) moves synchronously with the second piston (42).

10. The brake apply pump with clutching bi-stroke piston of claim 1 wherein: The piston push rod assembly (4) further comprises a piston sleeve (46), the piston sleeve (46) is arranged in the piston cavity (11), and the piston sleeve (46) is provided with a driving hole (461); The rotation and push mechanism (22) at least partially extends into the driving hole (461) from rear to front, the first piston (41) at least partially extends into the driving hole (461) from front to rear, and the front end of the rotation mechanism abuts against the rear end of the first piston (41) and forms a transmission cooperation; An inner sealing ring (6) is arranged between the outer wall of the first piston (41) and the inner wall of the piston sleeve (46), and an outer sealing ring (7) is arranged between the outer wall of the piston sleeve (46) and the inner wall of the piston cavity (11).

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