A hydraulic booster cylinder with an overflow structure

Abstract

The present invention provides a hydraulic assist cylinder with an overflow structure, belonging to the field of mechanical technology. It solves the problem of how to relieve pressure in the existing hydraulic assist cylinder. The hydraulic assist cylinder with an overflow structure includes a cylinder block having an oil inlet and an oil return port, a push rod, and a piston body disposed in the cylinder block. The inner end of the push rod extends into the cylinder block. An oil passage hole is formed in the piston body to communicate the oil inlet and the oil return port. An overflow valve core and an overflow spring separated from the push rod are disposed in the oil passage hole. A first sealing portion is provided on the hole wall of the oil passage hole, and a second sealing portion is provided at the inner end of the push rod, and the second sealing portion can abut against the first sealing portion. An overflow hole is further provided at the inner end of the push rod. The overflow valve core is disposed at the inner end of the push rod. The push rod can approach the overflow valve core and push the overflow valve core to compress the overflow spring, and the overflow valve core can block the overflow hole. The hydraulic assist cylinder with an overflow structure has the advantages of good stability and reliability.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical technology and relates to a hydraulic booster cylinder, in particular to a hydraulic booster cylinder with an overflow structure. Background Art

[0002] Existing hydraulic power cylinders generally include a cylinder body, a piston arranged in the cylinder body, and a push rod at the outer end for connecting to the vehicle pedal. The piston separates the cylinder body into an oil inlet chamber and an oil return chamber. The cylinder body is provided with an oil inlet port and an oil return port respectively connected to the oil inlet chamber and the oil return chamber. The piston is also provided with an oil passage that can connect the oil inlet chamber and the oil return chamber. The inner end of the push rod extends into the cylinder body and when the push rod moves inward, the inner end of the push rod can block the oil passage.

[0003] However, when the inner end of the push rod continues to block the oil passage, the pressure in the oil inlet chamber cannot be released, and the oil pressure continues to rise, which will cause the external oil supply equipment to bear an increasingly heavy load. Long-term use can easily shorten the life of the equipment or even cause damage.

[0004] In the face of this problem, conventional technical means adopted by those skilled in the art include:

[0005] 1. Connect an overflow structure between the oil inlet and the oil return port outside the cylinder body, such as the Chinese patent applied for by the applicant - Hydraulic Power Cylinder (application number: 201821990147.X). In this patent, an overflow structure is integrated on the outside of the cylinder body to relieve the oil pressure in the oil inlet chamber when it exceeds a critical value, so as to solve the problem of excessive load in the prior art;

[0006] Second, an overflow structure is separately provided in the piston or push rod in the cylinder body, such as the Chinese patent applied for by the applicant - hydraulic power cylinder with protective structure (its application number is: 201820208126.1; its announcement number is: CN207892921U). In this patent, an overflow structure capable of relieving pressure is added to the piston and push rod in the cylinder body, which can also relieve pressure when the oil pressure in the oil inlet chamber exceeds the critical value, so as to solve the problem of excessive load in the prior art.

[0007] The specific structures of the two overflow structures mentioned above often require a separate pressure relief channel to be opened in the piston or push rod and a valve core and spring to be installed in the pressure relief channel. In the default state, the valve core blocks the pressure relief channel under the elastic force of the spring. At this time, the spring is in a compressed state. When the force exerted by the pressure difference on both sides of the pressure relief channel is greater than the elastic force of the spring, the valve core is pushed open and the pressure relief channel will open to relieve pressure. The working principle of the above-mentioned overflow structure means that when the hydraulic power cylinder is put into use, regardless of whether the vehicle pedal is pressed, the spring is always in a compressed state. Even in some equipment with high pressure relief threshold requirements, the spring needs to be compressed significantly. The long-term compression of the spring will have a significant impact on the service life of the spring itself. After long-term use, it may even cause the elastic force to fail and the pressure relief channel to be easily opened, thereby affecting the normal use of the hydraulic power cylinder.

[0008] Therefore, the overflow structure in the hydraulic booster cylinder requires regular maintenance and replacement. To facilitate replacement, those skilled in the art often prefer solution 1, which involves placing the overflow structure outside the cylinder body to reduce maintenance and replacement costs. However, while the conventional techniques currently available to those skilled in the art can address the pressure relief issue, the overflow structure's replacement cycle is short, and the results are still less than ideal. Summary of the Invention

[0009] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a hydraulic booster cylinder with an overflow structure, thereby solving the problem of how to relieve pressure in the hydraulic booster cylinder.

[0010] The purpose of the present invention can be achieved through the following technical solutions:

[0011] A hydraulic booster cylinder with an overflow structure comprises a cylinder body with an oil inlet and an oil return port, a push rod and a piston body arranged in the cylinder body, the inner end of the push rod extends into the cylinder body, and an oil hole is provided in the piston body to connect the oil inlet and the oil return port. It is characterized in that an overflow valve core and an overflow spring separated from the push rod are provided in the oil hole, the hole wall of the oil hole is provided with a sealing part 1, the inner end of the push rod is provided with a sealing part 2, and the sealing part 2 can abut against the sealing part 1, the inner end of the push rod also has an overflow hole, the overflow valve core is provided at the inner end of the push rod, the push rod can approach the overflow valve core and push the overflow valve core to compress the overflow spring, and the overflow valve core can block the overflow hole.

[0012] The hydraulic booster cylinder with an overflow structure has an overflow hole opened at the inner end of the push rod and the position of the overflow valve core is opposite to the inner end of the push rod. When the operator does not step on the pedal, the push rod does not move into the cylinder body, the overflow valve core is separated from the push rod and is not affected by the force of the push rod. The compression of the overflow spring is small or even not compressed. The oil fluid sent into the cylinder body from the oil inlet can flow out through the oil hole and the oil return port. When the operator steps on the pedal, the push rod moves axially into the cylinder body. The first sealing part and the second sealing part abut against each other to form a seal, blocking the oil passing hole. During the movement of the push rod, the inner end of the push rod gradually approaches the overflow valve core and pushes the overflow valve core to compress the overflow spring. And the overflow valve core extends into and blocks the overflow hole under the elastic force of the overflow spring. At this time, both the oil passing hole and the overflow hole are blocked, and the oil pressure on one side of the piston body will gradually increase, thereby assisting in pushing the piston body to move. When the oil pressure on one side of the piston body is too high, the oil pressure acts on the overflow valve core, pushing the overflow valve core to compress the overflow spring and separate from the overflow hole, and the oil fluid can leak out through the overflow hole, realizing the pressure relief of the hydraulic booster cylinder and maintaining the stability of the oil pressure on the oil inlet side of the piston body.

[0013] During this working process, when the pedal is not stepped on, the push rod does not move, and the overflow valve core does not compress the overflow spring, so that the compression of the overflow spring is greatly reduced or even not compressed, that is, the elastic force of the overflow spring at this time is much smaller than the pressure relief critical value. When the pedal is stepped on, the overflow valve core is forced to compress the overflow spring, so that the elastic force of the overflow spring reaches the pressure relief critical value. That is, the overflow spring is only in a state of being greatly compressed when the push rod is working, and in a relatively relaxed state when the push rod is not working, reducing the working time of the continuous compression of the overflow spring, improving the stability and reliability of the use of the overflow spring, reducing the replacement frequency of the overflow spring, and thus reducing the maintenance and replacement cost.

[0014] In the above-mentioned hydraulic booster cylinder with an overflow structure, the first sealing part is annular, and the second sealing part includes a conical sealing surface located outside the inner end of the push rod. The aperture of the first sealing part is larger than the small end diameter of the second sealing part and smaller than the large end diameter of the second sealing part. The conical sealing surface can provide guidance for the inward movement of the push rod and adjust the position of the inner end of the push rod so that the first sealing part and the second sealing part can abut and seal better, ensuring the relative position of the push rod and the overflow valve core to improve the accuracy of the overflow valve core blocking the pressure relief channel, and also avoiding the misalignment of the push rod and the overflow valve core and excessive compression of the overflow spring, ensuring the stability and reliability of the use of the overflow spring.

[0015] As another case, in the above-mentioned hydraulic booster cylinder with an overflow structure, the first sealing part is annular, and the second sealing part includes a stepped surface located outside the inner end of the push rod. The end of the inner end of the push rod can extend into the first sealing part. The push rod can also adopt a stepped structure for sealing. The small end extends into the first sealing part for guidance and support, and the large end is used to abut and seal with the first sealing part.

[0016] In the aforementioned hydraulic booster cylinder with an overflow structure, the wall of the oil hole further comprises an inlet and an outlet. The inlet connects the oil hole with the oil inlet, and the outlet connects the oil hole with the oil return port. The overflow valve core and overflow spring are located on one side of the outlet, while the inlet is located on the other side of the outlet. The overflow valve core, overflow spring, and inlet are located on either side of the outlet, respectively, so that oil entering the oil hole from the inlet and exiting the oil hole from the outlet does not pass through the overflow valve core, thereby reducing the impact on the overflow valve core and the overflow spring, and ensuring the stability and reliability of the overflow spring during subsequent use.

[0017] In the aforementioned hydraulic booster cylinder with an overflow structure, the oil hole has a protruding, annular shoulder on its sidewall, the outlet hole is formed on the shoulder, and the overflow valve core has a protruding, annular shoulder on its exterior that abuts against the shoulder. The arrangement of the shoulder and the shoulder ensures that the overflow valve core can abut stably against the shoulder, preventing the overflow valve core itself or shaking during oil flow. This prevents noise generation and reduces the impact on the overflow spring, ensuring the stability and reliability of the overflow spring during use.

[0018] In the aforementioned hydraulic booster cylinder with an overflow structure, the overflow hole comprises a first pressure relief hole radially extending through the sidewall of the inner end of the push rod, and a second pressure relief hole axially extending therethrough. One end of the second pressure relief hole communicates with the middle portion of the first pressure relief hole, and the other end of the second pressure relief hole is formed on the end surface of the inner end of the push rod. The overflow valve core faces the end of the push rod and is positioned opposite the second pressure relief hole. This arrangement of the first and second pressure relief holes not only facilitates opening but also increases the amount of oil flowing through the first pressure relief hole, thereby accelerating the pressure relief process.

[0019] In the aforementioned hydraulic booster cylinder with a relief structure, the relief valve core has a tapered guide surface on the outer side of one end facing the push rod. The end of the relief valve core can partially extend into the end of the relief hole, causing the guide surface to abut and seal against the inner wall of the relief hole. The guide surface on the relief valve core provides guidance for the relief valve core to extend into the end of the relief hole and achieve sealing, thereby improving sealing accuracy. Combined with the tapered sealing surface on the inner end of the push rod, this further improves the sealing accuracy of the relief valve core against the relief hole.

[0020] In another embodiment, in the aforementioned hydraulic booster cylinder with an overflow structure, the overflow valve core includes a ball support and a steel ball. The ball support has a concave spherical hole, and the steel ball is partially disposed within the hole. The steel ball-type overflow valve core can be well embedded in the overflow hole and achieve a circumferential seal.

[0021] In the above-mentioned hydraulic power cylinder with an overflow structure, the push rod includes a sealing valve core, a telescopic spring, and rod one and rod two, both of which are rod-shaped. The outer end of rod one extends out of the cylinder body, and the inner end of rod one is sleeved on the outside of the outer end of rod two. The telescopic spring is arranged between rod one and rod two, and rod one and rod two can move toward each other and compress the telescopic spring. The sealing valve core is fixedly connected to the inner end of rod two, and the above-mentioned sealing part two and the overflow hole are both located on the sealing valve core.

[0022] As another case, in the above-mentioned hydraulic booster cylinder with an overflow structure, the push rod is an integrated structure.

[0023] Compared with the existing technology, the overflow spring in the hydraulic power cylinder with an overflow structure is only in a greatly compressed state when the push rod is working, and is in a relatively relaxed state when the push rod is not working, which reduces the working time of the overflow spring being continuously compressed, improves the stability and reliability of the use of the overflow spring, reduces the replacement frequency of the overflow spring, and thus reduces the maintenance and replacement costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic cross-sectional view of the hydraulic booster cylinder with an overflow structure.

[0025] Figure 2 This is a partial enlarged view of the hydraulic power cylinder with overflow structure.

[0026] Figure 3 This is a partial enlarged view of the hydraulic booster cylinder with an overflow structure after the push rod moves inward.

[0027] In the figure, 1. cylinder body; 11. oil inlet chamber; 12. oil return chamber; 13. oil inlet port; 14. oil return port; 2. piston body; 21. oil hole; 21a. liquid inlet hole; 21b. liquid outlet hole; 23. shoulder; 23a. sealing part 1; 3. push rod; 31. overflow hole; 31a. pressure relief hole 1; 31b. pressure relief hole 2; 32. sealing surface; 33. rod 1; 34. rod 2; 35. telescopic spring; 36. sealing valve core; 4. overflow valve core; 41. boss; 42. guide surface; 5. overflow spring. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0029] like Figure 1 and Figure 2As shown, the hydraulic booster cylinder with an overflow structure includes a cylinder body 1 having an oil inlet 13 and an oil return port 14, a piston body 2 disposed within the cylinder body 1, and a push rod 3. The piston body 2 separates the cylinder body 1 into an oil inlet chamber 11 connected to the oil inlet 13 and an oil return chamber connected to the oil return port 14. The piston body 2 includes an oil passage hole 21 that connects the oil inlet chamber 11 and the oil return chamber 12. The inner end of the push rod 3 extends into the cylinder body 1, and the outer end extends out of the cylinder body 1. When the push rod 3 moves axially into the cylinder body 1, the inner end of the push rod 3 can block the oil passage hole 21. In this embodiment, the piston body 2 includes a piston body, a rod-shaped piston rod, and a locking cap. The piston rod is disposed within the body and fixed to the body. The oil passage hole 21 is an inner hole axially opened in the piston rod. The inner end of the push rod 3 extends into the piston rod from the outer end of the piston rod. The locking cap is threadedly connected to the inner end of the piston rod, and a seal is formed between the locking cap and the inner end of the piston rod.

[0030] A relief valve core 4 and a relief spring 5 are disposed within the oil passage 21. The relief valve core 4 is located between the relief spring 5 and the push rod 3, and the relief valve core 4 is directly opposite the inner end of the push rod 3. A liquid inlet hole 21a, which communicates with the oil inlet chamber 11, and a liquid outlet hole 21b, which communicates with the oil return chamber 12, are formed through the wall of the oil passage 21. The relief valve core 4 and the relief spring 5 are located on one side of the liquid outlet hole 21b, and the liquid inlet hole 21a is located on the other side of the liquid outlet hole 21b.

[0031] Specifically, the oil hole 21 has a protruding, annular shoulder 23 on its sidewall. The liquid outlet 21b is radially located in the middle of the shoulder 23. The relief valve core 4 and the push rod 3 are located on either side of the shoulder 23. The end of the shoulder 23 facing the push rod 3 forms a sealing portion 23a. The relief valve core 4 has a protruding, annular shoulder 41 on its outer side, which abuts against the end surface of the shoulder 23. The end of the relief valve core 4 facing the push rod 3 extends through the shoulder 23, leaving a gap between the outer wall of the relief valve core 4 and the inner wall of the shoulder 23 for oil to pass through. In this embodiment, the overflow valve core 4 has a cylindrical guide portion at the end facing the overflow spring 5. The overflow spring 5 is sleeved on the outside of the guide portion. One end of the overflow spring 5 abuts against the piston body 2, and the other end abuts against the shoulder 41. The end of the overflow valve core 4 facing the push rod 3 is cylindrical and has a conical guide surface 42 on the outside of its end. Of course, the overflow valve core 4 can be replaced as needed. For example, the overflow valve core 4 includes a ball core bracket and a steel ball. The ball core bracket has a concave spherical recess, and the steel ball is partially disposed in the recess.

[0032] The inner end of the push rod 3 is also provided with an overflow hole 31 that can connect the oil inlet chamber 11 and the oil return chamber 12. One of the ports of the overflow hole 31 is opposite to the overflow valve core 4. When the push rod 3 moves into the cylinder body 1, it can approach and push the overflow valve core 4 to compress the overflow spring 5, and the overflow valve core 4 can rest on the port of the overflow hole 31 and block the overflow hole 31.

[0033] Among them, there is a gap between the outer wall of the push rod 3 and the side wall of the oil passage hole 21. The overflow hole 31 includes a first pressure relief hole 31a that penetrates radially through the side wall of the inner end of the push rod 3 and a second pressure relief hole 31b that is axially provided. One end of the second pressure relief hole 31b is connected to the middle of the first pressure relief hole 31a, and the other end of the second pressure relief hole 31b is opened on the end face of the inner end of the push rod 3. One end of the overflow valve core 4 facing the push rod 3 is opposite to the position of the second pressure relief hole 31b and can partially extend into the second pressure relief hole 31b, and is in sealing contact with the inner wall of the second pressure relief hole 31b by the guide surface 42. On the outer side of the inner end of the push rod 3, there is also a conical sealing surface 32 serving as the second sealing part, and this sealing surface 32 can abut against the first sealing part 23a of the shoulder 23 to form a seal. In this embodiment, the push rod 3 includes a sealing valve core 36, a telescopic spring 35, and a first rod 33 and a second rod 34 that are both rod-shaped. The outer end of the first rod 33 extends out of the cylinder block 1, the inner end of the first rod 33 is sleeved outside the outer end of the second rod 34, the telescopic spring 35 is arranged between the first rod 33 and the second rod 34, and the first rod 33 and the second rod 34 can move towards each other and compress the telescopic spring 35. The sealing valve core 36 is fixedly connected to the inner end of the second rod 34, and both the sealing surface 32 and the overflow hole 31 are located on the sealing valve core 36. If necessary, the push rod 3 can also be designed as an integral structure.

[0034] After the hydraulic booster cylinder with an overflow structure is installed on the machine, when the operator does not step on the pedal, the push rod 3 moves outwards under the elastic force of the return spring, the overflow valve core 4 is separated from the push rod 3, the overflow valve core 4 is not affected by the force of the push rod 3 and does not compress the overflow spring 5, the compression amount of the overflow spring 5 is small or even not compressed, and the overflow valve core 4 is blocked by the shoulder 23 at one end of the oil passage hole 21. The oil fluid enters the oil inlet cavity 11 from the oil inlet 13 of the cylinder block 1, then flows out to the oil return cavity 12 through the liquid inlet hole 21a, the oil passage hole 21, and the liquid outlet hole 21b, and returns to the fuel tank from the oil return port 14.

[0035] As Figure 3 shown, when the operator steps on the pedal, it pushes the push rod 3 to move axially into the cylinder block 1 until the sealing surface 32 at the inner end of the push rod 3 abuts against the first sealing part 23a of the shoulder 23 and forms a seal between the two, blocking the oil passage hole 21. During the movement of the push rod 3, the inner end of the push rod 3 gradually approaches the overflow valve core 4, and the end of the overflow valve core 4 also gradually extends into the second pressure relief hole 31b and forms a seal by abutting against the inner wall of the second pressure relief hole 31b through the guide surface 42. The push rod 3 continues to be pushed inwards until it abuts against the shoulder 23. At this time, the overflow valve core 4 is compressed by the force applied by the inner end of the push rod 3 and moves inwards by compressing the overflow spring 5. The overflow valve core 4 tightly abuts against the second pressure relief hole 31b of the push rod 3 by the elastic force of the overflow spring 5 to achieve sealing and block the overflow hole 31. At this time, both the oil passage hole 21 and the overflow hole 31 are blocked, and the oil pressure on the side of the oil inlet cavity 11 will gradually increase, thereby assisting in pushing the piston body 2 to move.

[0036] When the oil pressure on one side of the oil inlet chamber 11 is too high, the oil pressure acts on the overflow valve core 4 through the second pressure relief hole 31b, pushing the overflow valve core 4 away from the push rod 3 and compressing the overflow spring 5. The oil on one side of the oil inlet chamber 11 can then be discharged to the oil return chamber 12 through the overflow hole 31, the oil passage hole 21, and the liquid outlet hole 21b, realizing the pressure relief on one side of the oil inlet chamber 11 of the hydraulic assist cylinder and maintaining the stable oil pressure on one side of the oil inlet chamber 11.

[0037] In addition to the above solution, the second sealing portion at the inner end of the push rod 3 may further include a stepped surface located outside the inner end of the push rod 3, that is, the push rod 3 has a stepped structure with a smaller inner end and a larger outer end. The diameter of the inner end of the push rod 3 is smaller than the inner hole diameter of the shoulder 23, while the outer diameter at the stepped surface of the push rod 3 is larger than the inner hole diameter of the shoulder 23, and the sealing is achieved by the abutment of the stepped surface against the first sealing portion 23a.

[0038] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways of substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A hydraulic booster cylinder with an overflow structure, comprising a cylinder block (1) having an oil inlet (13) and an oil return port (14), a push rod (3), and a piston body (2) disposed within the cylinder block (1). The inner end of the push rod (3) extends into the cylinder block (1). An oil passage hole (21) is formed within the piston body (2) to communicate the oil inlet (13) and the oil return port (14). It is characterized in that, An overflow valve core (4) and an overflow spring (5) separated from the push rod (3) are arranged in the oil passing hole (21). A first sealing part (23a) is provided on the pore wall of the oil passing hole (21). The inner end of the push rod (3) has a second sealing part, and the second sealing part can abut against the first sealing part (23a). The inner end of the push rod (3) also has an overflow hole (31). The overflow valve core (4) is arranged at the inner end of the push rod (3). The push rod (3) can approach the overflow valve core (4) and push the overflow valve core (4) to compress the overflow spring (5). The overflow valve core (4) can block the overflow hole (31). A liquid inlet hole (21a) and a liquid outlet hole (21b) are also formed in the pore wall of the oil passing hole (21). The liquid inlet hole (21a) can communicate the oil passing hole (21) with the oil inlet (13). The liquid outlet hole (21b) can communicate the oil passing hole (21) with the oil return port (14). The overflow valve core (4) and the overflow spring (5) are located on one side of the liquid outlet hole (21b), and the liquid inlet hole (21a) is located on the other side of the liquid outlet hole (21b). A shoulder (23) protruding in a ring shape is provided on the side wall of the oil passing hole (21). The liquid outlet hole (21b) is formed in the shoulder (23). A shoulder (41) protruding in a ring shape is provided on the outer side of the overflow valve core (4), and the shoulder (41) can abut against the shoulder (23).

2. The hydraulic assist cylinder with an overflow structure according to claim 1, characterized in that, The first sealing part (23a) is in a ring shape. The second sealing part includes a conical sealing surface (32) located on the outer side of the inner end of the push rod (3). The aperture of the first sealing part (23a) is larger than the small end diameter of the second sealing part and smaller than the large end diameter of the second sealing part.

3. The hydraulic assist cylinder with an overflow structure according to claim 1, characterized in that, The first sealing part (23a) is in a ring shape. The second sealing part includes a stepped surface located on the outer side of the inner end of the push rod (3). The end of the inner end of the push rod (3) can extend into the first sealing part (23a).

4. A hydraulic booster cylinder with an overflow structure according to claim 1 or 2 or 3, characterized in that, The overflow hole (31) includes a first pressure relief hole (31a) penetrating through the side wall of the inner end of the push rod (3) in the radial direction and a second pressure relief hole (31b) formed in the axial direction. One end of the second pressure relief hole (31b) is communicated with the middle of the first pressure relief hole (31a), and the other end of the second pressure relief hole (31b) is formed on the end surface of the inner end of the push rod (3). The end of the overflow valve core (4) facing the push rod (3) is opposite to the position of the second pressure relief hole (31b).

5. A hydraulic assist cylinder with an overflow structure according to claim 1 or 2 or 3, characterized in that, A conical guiding surface (42) is provided on the outer side of the end of the overflow valve core (4) facing the push rod (3). The end of the overflow valve core (4) can partially extend into the port of the overflow hole (31) and make the guiding surface (42) abut against and seal the inner wall of the overflow hole (31).

6. A hydraulic booster cylinder with an overflow structure according to claim 1 or 2 or 3, characterized in that The overflow valve core (4) includes a ball core support and a steel ball. A concave spherical hole is provided on the ball core support, and the steel ball is partially arranged in the hole.

7. A hydraulic booster cylinder with an overflow structure according to claim 1 or 2 or 3, characterized in that The push rod (3) includes a sealing valve core (36), a telescopic spring (35), and a first rod (33) and a second rod (34) both in a rod shape. The outer end of the first rod (33) extends out of the cylinder block (1), and the inner end of the first rod (33) is sleeved outside the outer end of the second rod (34). The telescopic spring (35) is arranged between the first rod (33) and the second rod (34), and the first rod (33) and the second rod (34) can move towards each other and compress the telescopic spring (35). The sealing valve core (36) is fixedly connected to the inner end of the second rod (34), and the above-mentioned second sealing part and the overflow hole (31) are both located on the sealing valve core (36).

8. A hydraulic booster cylinder with an overflow structure according to claim 1 or 2 or 3, characterized in that, The push rod (3) is of an integral structure.

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