Bulk cylinder with self-exhausting function

Abstract

The utility model discloses a wheel cylinder with a self-exhausting function, which comprises a pump shell, a gas cavity and a liquid cavity arranged behind the gas cavity and communicated with the gas cavity are arranged in the pump shell, the front end of the gas cavity is open, and the liquid cavity is provided with a liquid cavity liquid inlet hole; the piston rod is arranged in the liquid cavity, and the front end of the piston rod extends into the air cavity; the piston disc is positioned in the air cavity and is fixed at the front end of the piston rod; the liquid cavity liquid inlet hole is located in the position, close to the first sealing assembly, of the top of the liquid cavity. The clutch has the function of automatically exhausting air in the liquid cavity when the piston rod returns, the influence of air residues in the liquid cavity on the stroke of a clutch system is avoided, and thorough separation of the clutch is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of automobile clutch operation, and relates to a clutch slave pump, in particular to a slave pump with a self-exhaust function. Background Art

[0002] The clutch slave cylinder (short for slave cylinder) is an important component of the automobile clutch operating mechanism. Its function is to control the engagement and disengagement of the clutch, thereby cutting off or transmitting the power output of the engine.

[0003] like Figure 1 As shown, the existing sub-pump has an air cavity 110 and a liquid cavity 120 in the pump housing 100. The liquid cavity 120 is located behind the air cavity 110, and the two are coaxially arranged and communicated with each other. A piston rod 210 is provided in the liquid cavity 120. The front end of the piston rod 210 extends into the air cavity 110, and a piston disc 220 is fixed to the front end of the piston rod 210. Seals are provided between the piston rod 210 and the liquid cavity 120, as well as between the piston disc 220 and the air cavity 110. A return spring 230 is also provided in the air cavity 110, located between the piston disc 220 and the rear wall of the air cavity 110. A push rod 300 extending forward is also connected to the front end surface of the piston rod 210. The rear end of the liquid cavity 120 has a liquid inlet 120m. In this existing sub-pump structure, the liquid inlet of the liquid cavity 120 is provided at the tail end of the liquid cavity 120. This results in that when the slave cylinder is installed and fixed in an inclined posture with the air cavity side slightly tilted upward, for example, tilted 5°, the position of the liquid inlet in the liquid cavity 120 is relatively low. When brake fluid is added to the liquid cavity, air will remain in the space above the liquid inlet position in the liquid cavity (i.e., the space above the dotted line a in the figure). This residual air cannot be discharged out of the liquid cavity, which will cause the brake fluid to fill the residual air area when the driver steps on the clutch pedal, consuming part of the volume of brake fluid that should have been used for the movement of the piston rod, thereby reducing the stroke efficiency of the clutch system, reducing the effective stroke, and causing incomplete clutch disengagement. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide an air pump with a self-exhaust function. During the operation of the sub-pump, no air will remain in the liquid cavity, thereby overcoming the shortcomings of the existing technology.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A slave pump with a self-exhaust function, comprising:

[0007] A pump housing, wherein the pump housing has an air cavity and a liquid cavity located behind and communicating with the air cavity, the front end of the air cavity is open, and the liquid cavity has a liquid inlet hole;

[0008] a piston rod, the piston rod being disposed in the liquid cavity and having a front end extending into the air cavity;

[0009] a piston disc, the piston disc being located in the air cavity and fixed to the front end of the piston rod;

[0010] a first sealing assembly, which is provided at the mouth of the liquid cavity and seals the gap between the piston rod and the liquid cavity;

[0011] a second sealing assembly, the second sealing assembly being provided on the circumferential surface of the piston disc and sealing the gap between the piston disc and the air cavity;

[0012] a return spring, the return spring being disposed in the air cavity, with its two ends respectively abutting against the piston disc and the rear wall of the air cavity;

[0013] The liquid inlet hole of the liquid cavity is located at a position on the top of the liquid cavity close to the first sealing component.

[0014] By adopting the above technical solution, since the liquid inlet hole of the liquid cavity is arranged at a position located at the top of the liquid cavity and close to the first sealing assembly, even if the air pump is installed and fixed in an inclined posture with the air cavity side tilted up, the liquid inlet hole of the liquid cavity is close to the highest point of the liquid cavity. In this way, when the piston rod returns, in the process of the liquid cavity discharging the brake fluid outward, the air at the top of the liquid cavity is discharged first, and it has the function of automatic exhaust, avoiding the influence of residual air in the liquid cavity on the stroke of the clutch system and ensuring the complete separation of the clutch.

[0015] In the present invention, the pump housing is further provided with an air inlet located behind the air cavity and an internal air duct connecting the air inlet and the air cavity. The air inlet is provided with an air valve for controlling the gas to enter the air cavity through the air inlet and the internal air duct. The front end of the air inlet is provided with an air inlet hole for the air inlet to drive the air valve. The side of the pump housing is provided with an inlet that is in communication with both the air inlet hole and the liquid cavity hole. By adopting such a technical solution, by introducing brake fluid into the inlet, it is possible to introduce brake fluid into the liquid cavity to drive the piston rod, or to introduce brake fluid into the air inlet to drive the air valve to open so as to introduce compressed air into the air cavity to drive the piston disc, so that the piston rod and the piston disc, driven by the brake fluid and compressed air respectively, jointly drive the slave cylinder to transmit power.

[0016] In the present invention, the first sealing assembly includes a first sealing ring and a second sealing ring. The first sealing ring has a sealing support groove on its end surface facing the liquid inlet hole of the liquid cavity, and the second sealing ring has a sealing support groove on its end surface facing the air cavity. With such a structure, the brake fluid entering the liquid cavity can quickly reach the first sealing ring at the first time, expand the sealing support groove, and then squeeze the inner and outer sealing lips of the first sealing ring to fit tightly with the cylindrical surface of the piston rod and the inner wall of the liquid cavity, respectively, to play a sealing role. The higher the brake fluid pressure in the liquid cavity, the better the sealing effect. In addition, when compressed air enters the air cavity, the compressed air will fill into the sealing support groove of the second sealing ring from the air cavity side, and then squeeze the inner and outer sealing lips of the second sealing ring to fit tightly with the cylindrical surface of the piston rod and the inner wall of the liquid cavity, respectively, to cooperate with the first sealing ring to play a secondary sealing role. The higher the gas pressure in the liquid cavity, the better the sealing effect.

[0017] In the present invention, the second sealing assembly includes a third sealing ring. A sealing ring mounting groove is defined on the circumferential surface of the piston disc, and the third sealing ring is mounted within the sealing mounting groove. The end surface of the third sealing ring facing the rear wall of the air cavity has a sealing support groove. With this structure, compressed air entering the air cavity also fills the sealing support groove of the third sealing ring, thereby squeezing the inner and outer sealing lips of the third sealing ring into close contact with the circumferential surface of the piston disc and the inner wall of the air cavity, respectively, thereby achieving a sealing effect. The higher the gas pressure in the air cavity, the better the sealing effect.

[0018] In the utility model, a gap is formed between the first and second sealing rings. During the reciprocating motion of the piston rod, the sealing effect of the first and second sealing rings creates a closed area in this gap, generating back pressure and causing the piston rod to move unsteadily. To prevent this, a vent is provided in the pump housing connecting this gap with the outside.

[0019] In the present invention, the top of the liquid chamber has a guide groove extending from the liquid inlet hole of the liquid chamber to the first sealing ring. The guide groove can further guide the liquid entering the liquid chamber to the first sealing ring.

[0020] In the present invention, a guide sleeve is fixed within the liquid chamber to fill the gap between the piston rod and the liquid chamber. By filling the gap between the piston rod and the liquid chamber, the guide sleeve guides the movement of the piston rod within the liquid chamber, preventing the piston rod from bouncing during axial movement within the liquid chamber and ensuring smooth axial movement of the piston rod.

[0021] In the present invention, a guide ring is provided on the circumferential surface of the piston disc in front of the third sealing ring, which is conducive to the smooth movement of the piston disc in the air cavity.

[0022] In the present invention, a push rod is connected to the front end of the piston rod. The front end of the piston rod has a ball socket, and the rear end of the push rod has a ball head. The ball head is secured in the ball socket by an elastic clamp, with the large end of the elastic clamp engaging the wall of the ball socket and the small end engaging the ball head. This fixing method does not restrict the ball head from rotating in the ball socket, thereby allowing the push rod to swing appropriately when transmitting force outward.

[0023] By adopting the above technical solution, the utility model has the function of automatically exhausting the air in the liquid cavity when the piston rod returns, avoiding the influence of residual air in the liquid cavity on the clutch system stroke and ensuring the complete separation of the clutch. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 It is a schematic diagram of the internal structure of the slave pump in the prior art;

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure of the slave pump of the present utility model;

[0027] Figure 3 This is a front view of the slave pump of the present utility model;

[0028] Figure 4 It is a rear view of the slave pump of the present utility model;

[0029] Figure 5 for Figure 4 Middle AA section view;

[0030] Figure 6 for Figure 4 Middle CC section view;

[0031] Figure 6A for Figure 6 An enlarged view of the air valve in FIG.

[0032] Figure 7 for Figure 4 Middle DD section view;

[0033] Figure 7A for Figure 7 Enlarged view of point E in the middle;

[0034] Figure 7B for Figure 7 Enlarged view of point F in the middle;

[0035] Figure 7C for Figure 7 Enlarged view of point G in the middle;

[0036] Figure 8 for Figure 4 A cross-sectional view in the HH direction in the intake state;

[0037] Figure 8A for Figure 8 Enlarged view at point I in the middle;

[0038] Figure 9 for Figure 4 A cross-sectional view in the exhaust state along the HH direction;

[0039] Figure 9A for Figure 9 Enlarged view of J in the middle;

[0040] Figure 10 for Figure 4 Middle KK section view;

[0041] Figure 10A for Figure 10 Enlarged view of L in the middle;

[0042] Figure 11 for Figure 3 Middle BB section view;

[0043] Figure 12 This is a schematic diagram of the slave cylinder of the present invention being arranged next to the gearbox. DETAILED DESCRIPTION

[0044] like Figures 2 to 6 , combined Figure 7 、 Figure 11 As shown, the slave pump with self-exhaust function of the present invention includes a pump housing 100 , a piston rod 210 , a piston plate 220 , a return spring 230 , a push rod 300 and an air valve 400 .

[0045] The pump housing 100 has an air cavity 110 , a liquid cavity 120 , an air inlet 410 and a liquid inlet 420 therein.

[0046] The liquid cavity 120 is located at the rear of the air cavity 110. The liquid cavity 120 and the air cavity 110 are connected and arranged coaxially. The cross-sectional area of the air cavity 110 is larger than the cross-sectional area of the liquid cavity 120. A cover plate 111 is installed at the front opening of the air cavity 110.

[0047] The piston rod 210 is disposed in the liquid chamber 120 and extends to the air chamber 110 . The piston disc 220 is disposed in the air chamber 110 and fixed to the front end return spring 230 of the piston rod 210 . The return spring 230 is disposed in the air chamber 110 and is located between the piston disc 220 and the rear wall of the air chamber 110 .

[0048] Combine Figure 7AAs shown, there is a gap between the piston rod 210 and the inner wall of the liquid chamber 120. A first sealing assembly 130 is provided in the liquid chamber 120 near the front end of the air chamber 11. A guide sleeve 121 is fixed to the liquid chamber 120 behind the first sealing assembly 130. The piston rod 210 is provided in the liquid chamber 120 and passes through the guide sleeve 121 and the first sealing assembly 130 in sequence and extends into the air chamber 110. The guide sleeve 121 is used to fill the gap between the piston rod 210 and the liquid chamber 120, guides the movement of the piston rod 210 in the liquid chamber 120, avoids the piston rod 210 from jumping when it moves axially in the liquid chamber 120, and ensures the smooth axial movement of the piston rod 210.

[0049] The first sealing assembly 130 is arranged between the liquid chamber 120 and the piston rod 210, and is composed of a first sealing ring 131, a first retaining ring 132, a first retaining spring 133, a second retaining ring 134, a second sealing ring 135, a third retaining ring 136 and a second retaining spring 137 from back to front.

[0050] The front end of the liquid chamber 120 has a stop step 120a near the guide sleeve 121, a first retaining groove 120b in the middle, and a second retaining groove 120c near the liquid chamber outlet. A first retaining spring 133 is embedded in the first retaining groove 120b, and a second retaining spring 137 is embedded in the second retaining groove 120c. A first retaining ring 132 and a second retaining ring 134 are disposed on the front and rear sides of the first retaining spring 133, respectively. A third retaining ring 136 is disposed on the rear side of the second retaining ring 137. A first sealing ring 132 is secured between the stop step 120a and the first retaining ring 132, and a second sealing ring 135 is secured between the second retaining ring 134 and the third retaining ring 136.

[0051] In this embodiment, the first sealing ring 131 has a sealing support groove 130a on its end surface facing the rear of the liquid chamber 120. The second sealing ring 135 also has a sealing support groove 130a on its end surface facing the air chamber 110. This arrangement offers the advantage that, upon entry of brake fluid into the liquid chamber 120, the pressured brake fluid quickly and immediately fills the sealing support groove 130a of the first sealing ring 131, thereby forcing the inner and outer sealing lips of the first sealing ring 131 to adhere tightly to the cylindrical surface of the piston rod 210 and the inner wall of the liquid chamber 120, respectively, thereby achieving a sealing effect. Furthermore, the higher the brake fluid pressure within the liquid chamber 120, the better the sealing effect. Similarly, when compressed air enters the air cavity 110, the compressed air will fill into the sealing expansion groove 130a of the second sealing ring 135 from the side of the air cavity 100, and then squeeze the inner and outer sealing lips of the second sealing ring 135 to fit tightly with the cylindrical surface of the piston rod 210 and the inner wall of the liquid cavity 120 respectively, cooperating with the first sealing ring to play a secondary sealing role, and the higher the gas pressure in the air cavity 110, the better the sealing effect.

[0052] A gap 122 is defined between the first sealing ring 131 and the second sealing ring 135. During the reciprocating motion of the piston rod 210, the sealing effect of the first and second sealing rings 131, 135 creates a sealed area within this gap, generating back pressure and causing the piston rod 210 to move unsteadily. To prevent this, the pump housing 100 includes a vent 120e connecting this sealed area 122 to the outside world.

[0053] Combine Figure 7C As shown, a second sealing assembly is provided on the circumferential surface of the piston disc 220. This second sealing assembly comprises a first groove 221 provided on the circumferential surface of the piston disc 220 and a third sealing ring 141 disposed within the first groove 221. The third sealing ring 141 is used to seal between the piston disc 220 and the circumferential inner wall of the air cavity 110. The sealing support groove 130a of the third sealing ring 141 faces the rear of the air cavity 110. This allows compressed air entering the air cavity 110 to flow into the sealing support groove 130a of the third sealing ring 141, thereby forcing the inner and outer sealing lips of the third sealing ring 141 into close contact with the circumferential surface of the piston disc 220 and the inner wall of the air cavity 110, respectively, thereby achieving a sealing effect. Furthermore, a second groove 222 is provided on the circumferential surface of the piston disc 220, forward of the first groove 221. A guide ring 142 is disposed within this second groove 222. The gap between the guide ring 142 and the air cavity 110 is very small, which can help the piston disc 220 move smoothly in the air cavity 110 .

[0054] Combine Figure 7B As shown, the front end face of the piston rod 210 is also provided with a ball socket 211. The push rod 300 passes through the cover plate 111, and its rear end has a semicircular ball head 301. The ball head 301 is installed in the ball socket 211 and is fixed by an elastic clip 302. The elastic clip 302 is a conical tubular structure that allows the ball head 301 to pass through. Its large end 302a is stuck on the hole wall of the ball socket 311, and the small end 302b is stuck on the ball head 301, fixing the ball head 301 to prevent the ball head 301 from falling out of the ball socket. In addition, this fixing method will not limit the rotation of the ball head 301 in the ball socket 211, thereby allowing the push rod 300 to swing appropriately when transmitting force outward.

[0055] For example Figure 7 and Figure 8 As shown, one end of return spring 230 abuts against a positioning groove 231 on the inner surface of piston plate 220, while the other end abuts against the rear wall of air chamber 110 and is positioned by a raised platform 232 protruding from the rear wall and surrounding the fluid chamber. The function of return spring 230 is to balance the reaction force of the clutch pressure plate when there is no compressed air in air chamber 110 and no brake fluid in fluid chamber 120, ensuring that piston plate 220 always returns to its initial position in air chamber 110.

[0056] Combine Figure 2 、 Figure 7 and Figure 12 As shown, the air inlet 410 is arranged parallel to the liquid chamber 120. Figure 6A As shown, the air valve 400 is installed in the air inlet duct 410 and includes a valve seat 401 , a sealing plug 402 , a cylinder 403 , a first spring 404 , a valve core 406 , a second spring 407 and an end cover 408 .

[0057] Recombination Figure 8 and Figure 8A As shown, the valve seat 401 and the cylinder 403 are fixed in the air inlet duct 410 by pressing the end cover. The valve seat 401 divides the air inlet duct 410 into a front chamber 410a and a rear chamber 410b. The sealing plug 402 is located in the rear chamber 410b, and its plug portion initially seals the valve seat opening 401a of the valve seat 401. The cylinder 403 is located behind the sealing plug 402. The plunger portion of the sealing plug 402 is located in the cylinder 403, and the two are sealed by a fourth sealing ring 403a. The sealing plug 402 can move axially forward and backward under the guidance of the cylinder 403. The first spring 404 is mounted on the cylinder 403 and is located between the flange at the rear end of the cylinder 403 and the plug portion of the sealing plug 402. The valve core 406 is arranged in the front cavity 410a, and the rear end of the valve core 406 has a head 406a that can pass through the valve seat opening 401a, and the second spring 407 is arranged between the valve seat 401 and the valve core 406. Under the elastic action of the second spring 407, in the initial state, there is a gap between the valve core 406 and the valve seat 401. The valve core 406 has an air passage 406b extending from the rear end face of the head 406a to the interior and a lateral air passage 406c connected from the air passage 406b to the side surface of the valve core 406. The position corresponding to the lateral air passage 406c in the front cavity 410a is provided with an exhaust channel 411a connected to the outside. The valve core 406 is provided with a fifth sealing ring 406d (such as Figure 6A A sealing gasket 402a is provided on the front end of the plug portion of the sealing plug 402, which provides a seal when in contact with the valve seat opening 401a of the valve seat 401 or the head portion 406a of the valve core 406. A fourth sealing ring 403a is provided on the circumferential surface of the plunger portion of the sealing plug 401.

[0058] Combined with Figure 2 As shown, the rear end of the air inlet 410 has an air inlet interface 405 that is horizontal and perpendicular to the air inlet 410. The air inlet interface 405 is connected to the rear cavity 410b. The air inlet interface 405 is used to connect to a high-pressure air source.

[0059] Combine Figure 2 、 Figure 10 and Figure 10A As shown, an air hole 411 b is provided in the front cavity 410 a near the valve seat 401 , and an internal air passage 411 extending from the air hole 411 b to the rear wall of the air cavity 110 is provided in the pump housing 100 .

[0060] Combine Figure 2 and Figure 11 As shown, the pump housing 100 also has a liquid inlet 420. The liquid inlet 420 is horizontally perpendicular to the air inlet 410 and intersects with the air inlet 410 and the liquid cavity 120, respectively, and then forms an air inlet liquid inlet hole 421 (as shown in FIG. Figure 6A As shown in FIG), a liquid inlet hole 422 is formed at the top of the liquid cavity 120 near the guide sleeve 121 (as shown in FIG). Figure 7A shown).

[0061] Since the air inlet duct 410 is parallel to the liquid chamber 120 and does not tilt upward, the slave pump can be arranged at multiple locations beside the transmission. Figure 12 As shown, the slave cylinder 001 can be arranged at the upper left corner, the left side, and the bottom of the gearbox 002.

[0062] For example Figure 6A As shown, a blocking step 410c is provided in the middle of the front chamber 410a to prevent the valve core 406 from moving to the bottom of the front end of the front chamber 410a. Thus, with the blocking step 410 preventing the valve core 406 from moving to the bottom of the front end of the front chamber 410a, a gap always exists between the front end of the valve core 406 and the bottom of the front chamber 410a when the valve core 406 is in the initial state. This gap allows brake fluid to smoothly enter the front chamber 410a from the intake port 421.

[0063] When the driver steps on the clutch pedal, the clutch pedal will control the main pump in the vehicle clutch system to output brake fluid. The brake fluid enters the front cavity 410a of the intake duct 410 through the intake duct liquid inlet hole 421 through the liquid inlet channel 420 and enters the liquid cavity 120 through the liquid cavity liquid inlet hole 422.

[0064] When the brake fluid enters the front chamber 410a of the intake passage 410, it drives the valve core 406 to push open the sealing plug 402, separate it from the valve seat 401, and open the valve seat port 401a, so that the rear chamber 410b and the front chamber 410a are connected. At this time, the compressed air in the rear chamber 410b enters the front chamber 410a through the valve seat port 410b, and enters the air chamber 110 from the air hole 411b through the internal air passage 411 (that is, at this time, the intake interface 405, the rear chamber 410b, the valve seat port 401a of the valve seat 401, the front chamber 410a, the air hole 411, and the internal air passage 411 connected in sequence form an intake passage, as shown in FIG. Figure 8A and Figure 10AAs shown by the middle arrow, the piston disc 220 in the air chamber 110, under the action of the compressed air, and the piston rod 110 in the liquid chamber 120, under the action of the brake fluid, move forward together, driving the push rod 300 forward, thereby driving the clutch pressure plate and driven plate to separate. As the valve core 406 pushes open the sealing plug 402, the sealing plug 402 simultaneously blocks the opening of the central air passage 406b, preventing the compressed air that has flowed into the front chamber 410a from leaking out of the central air passage 406b.

[0065] When the driver releases the clutch pedal, the clutch pedal no longer controls the master pump's output of brake fluid to the slave pump, and the brake fluid in both the front chamber 410a and the fluid chamber 120 loses pressure. Consequently, the valve core 406 in the intake duct 410, under the action of the second spring 407, returns to its initial position. The sealing plug 402, under the action of the first spring 404, returns to the initial sealing position of the valve seat opening 401a of the valve seat 401, thus severing the connection between the rear chamber 410b and the front chamber 410a. Simultaneously, the push rod 300, under the reaction force of the clutch pressure plate, drives the piston rod 210 and piston plate 220 back together. During the retraction process, the piston rod 210 discharges the brake fluid in the liquid chamber from the liquid chamber inlet hole 422 via the liquid inlet channel 420 back to the main pump, and the piston plate 220 discharges the gas in the air chamber 110 through the internal air channel 411, the air hole 411b, the gap between the valve core 406 and the valve seat 401, the middle air channel 406b, the lateral air channel 406c, and the exhaust channel 411a to the outside of the slave pump (that is, at this time, the internal air channel 411, the air hole 411b, the gap between the valve core 406 and the valve seat 401, the middle air channel 406b, the lateral air channel 406c, and the exhaust channel 411a are connected in sequence to form an exhaust channel, as shown in FIG. Figure 9 、 Figure 9A arrows).

[0066] From the above description, it can be seen that the air valve 400 of the utility model can automatically switch between intake and exhaust according to whether brake fluid is introduced, and the switching is fast and reliable without any blowby problem.

[0067] For example Figure 8A As shown, an exhaust hole 402b extending from the rear end face to the front end face is further provided in the sealing plug 402. When the valve core 406 abuts the sealing plug 402, the exhaust hole 402b interfaces with the central air passage 406b, allowing the interior of the cylinder 403 to communicate with the outside via the exhaust hole 402b, the central air passage 406b, the lateral air passage 406c, and the exhaust passage 411a. This solves the problem of back pressure caused by the formation of a closed space inside the cylinder 403 when the sealing plug 402 moves back and forth, thereby preventing the travel of the sealing plug 401 from being affected.

[0068] like Figure 7 and Figure 7AAs shown, the liquid chamber inlet hole 422 is located at the top of the liquid chamber 120 and is disposed near the guide sleeve 121, that is, near the first sealing ring 131 of the sealing assembly 130. A guide groove 422a is also disposed at the top of the liquid chamber 120, extending from the liquid chamber inlet hole 422 to the first sealing ring 131. Because the liquid chamber inlet hole 422 is close to the first sealing ring 131 and the guide groove 422a has a diversion function, the brake fluid flowing in through the liquid chamber inlet hole 422 will first and quickly flow to the first sealing ring 131, initially expanding the first sealing ring 131 to quickly seal the piston rod 210 and improve the sealing effect. Setting the liquid inlet hole 422 at the top of the liquid cavity 120 is conducive to the automatic discharge of air in the liquid cavity 120, and has the function of automatic exhaust. There will be no air residue in the liquid cavity. Therefore, when the clutch pedal is stepped on to add brake fluid, there is no air residue area in the liquid cavity that needs to be filled with the added brake fluid first. The brake fluid will directly drive the piston rod, avoiding the influence of the residual air in the liquid cavity on the clutch system stroke, thereby ensuring the accuracy of the slave cylinder transmission control and the complete separation of the clutch.

[0069] Therefore, it can be seen from the above detailed description that the utility model has the function of automatically exhausting the air in the liquid chamber when the piston rod returns, avoiding the influence of residual air in the liquid chamber on the clutch system stroke and ensuring complete clutch separation.

Claims

1. A slave pump with a self-exhaust function, comprising: A pump housing, wherein the pump housing has an air cavity and a liquid cavity located behind and communicating with the air cavity, the front end of the air cavity is open, and the liquid cavity has a liquid inlet hole; a piston rod, the piston rod being disposed in the liquid cavity and having a front end extending into the air cavity; a piston disc, the piston disc being located in the air cavity and fixed to the front end of the piston rod; a first sealing assembly, which is provided at the mouth of the liquid cavity and seals the gap between the piston rod and the liquid cavity; a second sealing assembly, the second sealing assembly being provided on the circumferential surface of the piston disc and sealing the gap between the piston disc and the air cavity; a return spring, the return spring being disposed in the air cavity, with its two ends respectively abutting against the piston disc and the rear wall of the air cavity; The feature is that the liquid inlet hole of the liquid cavity is located at a position at the top of the liquid cavity close to the first sealing component.

2. The slave pump with self-exhaust function according to claim 1, characterized in that: The pump housing is also provided with an air intake duct located behind the air cavity and an internal air duct connecting the air intake duct and the air cavity. The air intake duct is provided with an air valve for controlling the gas to enter the air cavity through the air intake duct and the internal air duct. The front end of the protected air intake duct has an air intake duct liquid inlet hole for entering brake fluid to drive the air valve. The side of the pump housing is provided with a liquid inlet duct that is connected to both the air intake duct liquid inlet hole and the liquid cavity liquid inlet hole.

3. The slave pump with self-exhaust function according to claim 1, characterized in that: The first sealing assembly includes a first sealing ring and a second sealing ring. The first sealing ring has a sealing support groove on its end surface facing the liquid inlet of the liquid cavity, and the second sealing ring has a sealing support groove on its end surface facing the air cavity.

4. The slave pump with self-exhaust function according to claim 1, characterized in that: The second sealing assembly includes a third sealing ring. A sealing ring installation groove is provided on the circumferential surface of the piston disc. The third sealing ring is installed in the sealing installation groove. The end surface of the third sealing ring facing the rear wall of the air cavity has a sealing support groove.

5. The slave pump with self-exhaust function according to claim 3, characterized in that: There is a space between the first sealing ring and the second sealing ring, and there is a ventilation channel in the pump housing that connects the space with the outside.

6. The slave pump with self-exhaust function according to claim 3, characterized in that: The top of the liquid cavity is provided with a guide groove extending from the liquid inlet hole of the liquid cavity to the first sealing ring.

7. The slave pump with self-exhaust function according to claim 3, characterized in that: A guide sleeve for filling the gap between the piston rod and the liquid chamber is fixed behind the first sealing ring in the liquid chamber.

8. The slave pump with self-exhaust function according to claim 4, characterized in that: A guide ring is provided on the circumferential surface of the piston disc in front of the third sealing ring.

9. The slave pump with self-exhaust function according to claim 1, characterized in that: A push rod is connected to the front end surface of the piston rod, and the front end surface of the piston rod has a ball socket. The rear end of the push rod has a ball head, and the ball head is fixed in the ball socket by an elastic clip. The large end of the elastic clip is clamped on the inner wall of the ball socket, and the small end is clamped on the ball head.

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