CN210068405U

CN210068405U - High-pressure two-stage manual hydraulic pump

Info

Publication number: CN210068405U
Application number: CN201920516208.7U
Authority: CN
Inventors: 周黎明
Original assignee: Hubei Rui Precision Machinery Manufacturing Co Ltd
Current assignee: Hubei Rui Precision Machinery Manufacturing Co Ltd
Priority date: 2019-04-17
Filing date: 2019-04-17
Publication date: 2020-02-14
Anticipated expiration: 2029-04-17

Abstract

The utility model provides a pair of manual hydraulic pump of high pressure doublestage, including the pump body, pump head subassembly, high pressure check valve subassembly, low pressure check valve subassembly and low pressure shield assembly, low pressure shield assembly includes end cap, spring, disk seat, cuts off steel ball, response valve rod, case and valve rod cover. When the pressure is lower than a set value, the spring enables the steel ball to be propped against the valve seat, and the partition steel ball and the valve seat form a sealed partition between the low-pressure piston cavity and the discharge channel. When the outlet pressure reaches a certain value, the sensing valve rod pushes the partition steel ball open under the action of the pressure, the partition steel ball and the valve seat are separated from a sealing state, the low-pressure piston cavity is communicated with the discharge channel, and the low-pressure piston is shielded. The utility model provides a manual hydraulic pump of high pressure doublestage is provided with the two-stage piston, and the low pressure is filled the time two-stage piston simultaneous working, has improved the output flow of pump, and low pressure shield assembly shields low pressure piston work when reacing certain pressure.

Description

High-pressure two-stage manual hydraulic pump

Technical Field

The patent of the utility model relates to a manual hydraulic pump of high pressure, a manual hydraulic pump of high pressure doublestage with high, low pressure two-stage piston, especially one kind can respond to outlet pressure, and the manual hydraulic pump of low pressure stage piston is shielded to the automatic selection.

Background

The manual hydraulic pump is a simple and convenient hydraulic power source and is widely applied to the hydraulic field. However, most of manual hydraulic pumps in the current market are single-stage pumps, and the manual hydraulic pumps have the defects of small single-stroke displacement, low output flow, low filling speed and increased labor intensity of operators in use. Certainly, a small number of double-stage hydraulic pumps are available in the market, but the modes that low-pressure stage overflow is performed after a certain pressure is reached, and high-pressure stage output is performed continuously are adopted, so that when the low-pressure stage overflow is caused, a counter-acting force is given to an operator by the low-pressure stage piston and added to a counter-acting force of the high-pressure stage piston, and the operator needs to bear a larger force if keeping a pressing-down posture, so that the operation is relatively laborious. And the overflow pressure cannot be set too high, because too high overflow pressure can cause excessive reaction force, so that the operator cannot complete the corresponding operation, and accordingly, the filling pressure is limited, thereby affecting the capability of the dual-stage pump to reduce the labor intensity of the operator by reducing the pressing times. The utility model provides a manual hydraulic pump of high pressure doublestage has high, low pressure two-stage piston, and two-stage piston simultaneous working when filling the notes can improve the single stroke discharge capacity greatly, improves and fills the notes speed. When the pressure is increased to a certain pressure, the pump can automatically sense and shield the low-pressure piston, the low-pressure piston cavity does not generate pressure any more in the operation process, and only the high-pressure piston works, so that an operator can quickly and easily increase the pressure to the high pressure.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art not enough, and provide one kind can greatly reduced operator intensity of labour, the manual hydraulic pump of raising efficiency. Note that the upper, lower, front, and rear positions described in the present invention are based on the orientations and positional relationships shown in the drawings, and are only for the sake of simplifying the description, and do not imply any particular orientation or configuration of the pump body.

In order to achieve the above purpose, the utility model discloses following technical scheme: a high-pressure two-stage manual pump comprises a pump body, a pump head assembly, a high-pressure check valve assembly, a low-pressure check valve assembly and a low-pressure shielding device. The pump body is of a square structure, the pump head assembly is installed on the pump body, and the high-pressure check valve assembly, the low-pressure check valve assembly and the low-pressure shielding device are inserted into the pump body.

The pump head assembly comprises a pump head, a lifting lug, a pull rod, a lever, a piston rod, a connecting seal ring, a rod isolation seal, a body isolation seal, a high-pressure piston rod seal and a low-pressure piston rod seal. The pump head is a hollow cylinder structure and is connected to the pump body through threads at one end, and a connecting sealing ring is arranged at the root of the threads. The head of pump head screw thread end is provided with a boss, the boss terminal surface with pump body screw thread bottom surface contact location, it is sealed to be provided with body isolation between the boss terminal surface and the pump body. The diameter of the boss is smaller than the small diameter of the pump body thread, and an annular circulation channel is formed between the boss and the pump body. The piston rod penetrates through the hollow cavity of the pump body, and part of the piston rod enters the inner cavity of the pump body. And a rod isolation seal is arranged between the piston rod and the pump head. The piston rod, the pump body and the pump head enclose a piston cavity. The piston cavity is divided into a high-pressure piston cavity and a low-pressure piston cavity by the rod isolation seal and the body isolation seal. The pump head is provided with an inclined hole which is communicated with the low-pressure piston cavity and the annular circulation channel.

The tail section of the piston rod is hinged with the lever through a pin shaft, the middle section of the piston rod penetrates through a hollow cavity of the pump head, and the front section of the piston rod penetrates through the cavity of the pump head and enters an inner cavity of the pump body. Be provided with the guide ring between pump head inner chamber and the piston rod, the guide ring sets up the position that the middle section of piston rod is close to the piston rod end, the guide ring outside is provided with the snap ring, the snap ring restriction guide ring is to the pump head outside activity. And a low-pressure piston seal is arranged between the middle section of the piston rod and the pump body and is arranged on one side of the middle section of the piston rod, which is close to the front section of the piston rod. And a high-pressure piston rod seal is arranged between the front section of the piston rod and the pump head. The body isolation seal is disposed below the high pressure piston rod seal, and the rod isolation seal is between the high pressure piston rod seal and the low pressure piston rod seal. The space formed between the body isolation seal, the pump body, the pump head, the high-pressure piston rod seal and the front section of the piston rod is a high-pressure piston cavity. The space formed between the rod isolation seal, the piston rod, the pump head and the low pressure piston rod seal is a low pressure piston cavity.

Further, the diameter of the front section of the piston rod is smaller than that of the middle section of the piston rod.

The pump body is internally inserted with two check valve groups, namely a high-pressure check valve group and a low-pressure check valve group, and the two check valve groups respectively comprise an inlet check valve and an outlet check valve. The pump body is provided with a low-pressure flow passage hole which is communicated with the low-pressure check valve group and the annular circulation passage, so that the low-pressure check valve is communicated with the low-pressure piston cavity. The low-pressure flow passage hole is formed between an inlet one-way valve and an outlet one-way valve of the low-pressure one-way valve group, the outlet end of the inlet one-way valve is communicated with the low-pressure flow passage hole, and the inlet end of the outlet one-way valve is communicated with the low-pressure flow passage hole. The high-pressure one-way valve is communicated with the high-pressure piston cavity through a high-pressure communication hole in the pump body. The high-pressure communication hole is formed between an inlet one-way valve and an outlet one-way valve of the high-pressure one-way valve group, the outlet end of the inlet one-way valve is communicated with the high-pressure communication hole, and the inlet end of the outlet one-way valve is communicated with the high-pressure communication hole.

The low-pressure shielding device comprises a plug, a spring, a partition steel ball, a valve seat, a valve core sleeve, an induction rod, a limiting ring and an elastic check ring, and the components are arranged on the same axis coincident with the central line of the pump outlet circulation hole. The pump outlet flow hole is a step hole, the valve seat is arranged at the bottom of the step hole and is in contact with the step surface, and a partition sealing ring is arranged between the valve seat and the wall of the step hole. The valve core sleeve is arranged in the pump outlet circulation hole, one end of the valve core sleeve is tightly attached to the valve seat, and a sealing ring is arranged between the valve core sleeve and the wall of the pump outlet circulation hole. The valve seat and the valve core sleeve are both of hollow structures, and the front end of the induction rod penetrates through inner holes of the valve core and the valve seat. And a sealing ring is arranged between the front end of the induction rod and the valve core sleeve. The diameter of the rear end of the induction rod is larger than that of the front end of the induction rod, and the induction rod cannot penetrate through the inner hole of the valve core sleeve. The limiting ring is of a cup-shaped structure, the cup opening faces the valve core sleeve, and the rear end of the induction rod is wrapped in the cup, so that the rear end of the induction rod can only move between the cup bottom of the cup-shaped structure and the valve core sleeve. The cup bottom of the cup-shaped structure faces the outlet port of the pump, and the cup bottom is provided with a small hole, so that the outlet end of the pump can be communicated with the induction rod. And the bottom end of the limiting ring cup is provided with an elastic retainer ring for limiting the movement of the limiting ring. The pump body is equipped with the end cap in the one side of pump mouth dorsad, the end cap adopts threaded connection on the pump body, and is provided with the sealing washer with pump body inner wall between. The one end that the end cap is towards pump export sets up the blind hole, be provided with the spring in the blind hole, spring one end with end cap blind hole ground contact, the other end and cut off the steel ball contact. The partition steel ball is arranged between the valve seat and the spring and is in contact with the valve seat. And a valve seat sealing surface is arranged at the contact part of the valve seat and the partition steel ball.

The low-pressure shielding device comprises a low-pressure shielding device, a pump inlet, a valve seat, a low-pressure shielding device discharge hole, a pump outlet, a pump inlet hole, 4 small holes and a valve seat inner hole, wherein the valve seat outer diameter of the low-pressure shielding device is provided with an annular groove, the annular groove is communicated with the pump inlet through the low-pressure shielding device discharge hole, and the bottom of the annular groove is uniformly distributed. The front section of the induction rod is divided into two sections, namely an induction section and a force transmission section, the force transmission section is close to the partition steel ball, and the induction section is close to the rear end of the induction rod. The diameter of the force transmission section is smaller than that of the inner hole of the valve seat, and an annular flow space is formed between the force transmission section and the inner wall of the valve seat. The annular circulation space may communicate the low-pressure shielding-device discharge hole and the shielding-device communication hole.

The partition sealing ring between the valve seat and the inner wall of the pump is arranged between the low-pressure shielding device discharge hole and the shielding device communication hole, and the sealing surface between the partition steel ball and the valve seat is arranged between the low-pressure shielding device discharge hole and the shielding device communication hole. When the pressure of the pump outlet is lower than the set value of the spring, the low-pressure shielding device discharge hole and the shielding device communication hole are isolated, and the low-pressure piston and the high-pressure piston work simultaneously.

When the pressure of the pump outlet is greater than the set pressure of the spring, the induction rod can move towards the partition steel ball through the valve seat inner hole under the action of pressure and push the partition steel ball open, so that the low-pressure shielding device discharge hole is communicated with the shielding device communication hole, the low-pressure piston cavity is communicated with the pump inlet, and the low-pressure piston is shielded. The diameter of a sealing surface between the valve seat and the partition steel ball is equal to the diameter of an inner hole of the valve seat and larger than the diameter of a sensing section of the sensing rod, so that before the low-pressure shielding device is shielded, the pressure of a low-pressure piston cavity acts on the partition steel ball through a shielding device communication hole when a rocker of the down-pressure pump is pressurized in operation, and meanwhile, the pressure of the low-pressure piston cavity reaches the outlet of the pump through the low-pressure one-way valve bank and acts on the sensing rod. At the moment, the force acting on the separation steel ball is certain to be larger than the force acting on the induction rod, and the separation steel ball cannot be pushed away. Therefore, the low-pressure piston is prevented from being shielded in the process of pressurizing the force by the operator, and the phenomenon that the operator falls down due to the fact that the counterforce of the pump is suddenly reduced in the process of pressurizing the force by the operator is avoided.

Compared with the prior art, the utility model discloses there is following advantage:

the utility model discloses have high-low pressure two-stage piston, two-stage piston simultaneous working when filling the notes can improve the single stroke discharge capacity greatly, improves and fills notes speed. When the pressure is increased to a certain pressure, the pump can automatically sense and shield the low-pressure piston, the low-pressure piston cavity does not generate pressure any more in the operation process, and only the high-pressure piston works, so that an operator can quickly and easily increase the pressure to the high pressure. Greatly reducing the labor intensity of operators and improving the labor efficiency.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a cross-sectional view of the high-pressure two-stage manual hydraulic pump according to the present invention; the whole and pump head components are schematically shown in structure;

FIG. 2 is a schematic structural view of the high pressure check valve assembly and the low pressure check valve assembly of the present invention;

fig. 3 is a schematic structural view of the low-voltage shielding device of the present invention;

FIG. 4 is a schematic structural view of the high-pressure flow passage hole and the low-pressure flow passage hole of the present invention;

fig. 5 is a schematic structural view of the one-way valve inlet flow passage hole of the present invention.

In the figure: the pump body 1, the pump head assembly 2, the high-pressure check valve assembly 3, the low-pressure check valve assembly 4, the low-pressure shield 5, the inlet end 101, the outlet end 102, the shield communication hole 103, the low-pressure shield bleed hole 104, the pump inlet flow passage hole 105, the T-shaped pin 106/120, the check valve inlet flow passage hole 107/108, the high-pressure flow passage hole 109, the low-pressure flow passage hole 110, the inclined hole 111, the check valve outlet flow passage hole 113/114/115, the plug 116/118/119, the seal 112/117/121/122, the lifting lug 201, the pull rod 202, the lever 203, the piston rod 204, the pump head 205, the rod isolation seal 206, the connecting seal ring 207, the high-pressure piston rod seal 208, the body isolation seal 209, the high-pressure piston cavity 210, the low-pressure piston cavity 211, the pin shaft 212, the low-pressure piston rod seal 213, the guide ring, Valve seat 303, steel ball 304, guide sleeve 305, spring 306, outlet check valve 307, valve seat 308, steel ball 309, guide sleeve 310, spring 311, threaded ring 312, seal 313/314, socket cap set screw 315, inlet check valve 401, seal 402, valve seat 403, steel ball 404, guide sleeve 405, spring 406, outlet check valve 407, valve seat 408, steel ball 409, guide sleeve 410, spring 411, threaded ring 412, seal 413/414, socket cap set screw 415, plug 501, spring 502, plug seal 503, steel ball 504, seal 505/508/510, sensing rod 506, valve seat 507, valve core sleeve 509, limit ring 511, and orifice retainer 512.

Detailed Description

In order to more fully understand the technical content of the present invention, the technical solution of the present invention will be further described and explained with reference to the specific embodiments.

As shown in fig. 1: a manual two-stage hydraulic pump comprises a pump body 1, a pump head assembly 2, a high-pressure check valve assembly 3, a low-pressure check valve assembly 4 and a low-pressure shielding device 5. The pump body 1 is a square structure, the pump head assembly 2 is installed on the pump body 1, and the high-pressure check valve assembly 3, the low-pressure check valve assembly 4 and the low-pressure shielding device 5 are inserted into the pump body 1. The lifting lug 201 of the pump head assembly 2 is connected with the pump body 1 through threads, one end of the pull rod 202 is connected with the lifting lug 201 through a pin shaft 212, and the other end of the pull rod is connected with one end of the lever 203 through the pin shaft 212.

Further, the pump head 205 is a hollow cylinder structure, and is connected to the pump body 1 through a thread at one end, and a connection sealing ring 207 is disposed at the root of the thread. The head of the screw thread end of the pump head 205 is provided with a boss, the boss end face is in contact with the bottom face of the pump body screw thread for positioning, and a body isolation seal 209 is arranged between the boss end face and the pump body 1. The diameter of the boss is smaller than the small diameter of the pump body thread, and an annular circulation channel is formed between the boss and the pump body. The piston rod 204 passes through the hollow cavity of the pump body and partially enters the inner cavity of the pump body 1. A rod isolation seal 206 is provided between the piston rod 204 and the pump head 205. The piston rod 204, pump body and pump head 205 enclose a piston chamber. The piston chamber is divided into two parts, a high pressure piston chamber 210 and a low pressure piston chamber 211 by the rod isolation seal 206 and the body isolation seal 209. The pump head 205 is provided with an inclined hole 111, and the inclined hole 111 communicates the low pressure piston chamber 211 and the annular flow passage.

Further, the diameter of the front section of the piston rod 204 is smaller than the diameter of the middle section of the piston rod.

Further, two check valve sets, namely a high-pressure check valve set 3 and a low-pressure check valve set 4, are inserted into the pump body 1, and each check valve set comprises an inlet check valve 301/401 and an outlet check valve 307/407. The pump body is provided with a low-pressure flow passage hole 110, and the low-pressure flow passage hole 110 is communicated with the low-pressure check valve group 4 and the annular circulation channel, so that the low-pressure check valve group 4 is communicated with the low-pressure piston cavity 211. The low pressure flow passage hole 110 is provided between an inlet check valve 401 and an outlet check valve 407 of the low pressure check valve group 4, an outlet end of the inlet check valve 401 is communicated with the low pressure flow passage hole 110, and an inlet end of the outlet check valve 407 is communicated with the low pressure flow passage hole 110. The high-pressure check valve group 4 is communicated with the high-pressure piston cavity 210 through a high-pressure communication hole 109 on the pump body. The high-pressure communication hole 109 is arranged between an inlet check valve 301 and an outlet check valve 307 of the high-pressure check valve group 3, the outlet end of the inlet check valve 301 is communicated with the high-pressure communication hole 109, and the inlet end of the outlet check valve 307 is communicated with the high-pressure communication hole 109.

Further, the low-pressure shielding device 5 comprises a plug 501, a spring 502, a steel ball 504, a valve seat 507, a valve core sleeve 509, an induction rod 506, a limiting ring 511 and a circlip 512, which are arranged on the same axis which is coincident with the central line of the pump outlet flow hole. The pump outlet flow hole is a step hole, the valve seat 507 is arranged at the bottom of the step hole and is in contact with the step surface, and a partition sealing ring 505 is arranged between the valve seat 507 and the wall of the step hole. The valve core sleeve 509 is arranged in the pump outlet flow hole, one end of the valve core sleeve is tightly attached to the valve seat 507, and a sealing ring 508 is arranged between the valve core sleeve 509 and the wall of the pump outlet flow hole. The valve seat 507 and the valve core sleeve 509 are both hollow structures, and the front section of the induction rod 506 is arranged in inner holes of the valve core sleeve 509 and the valve seat 507 in a penetrating mode. A sealing ring 510 is arranged between the front section of the sensing rod 506 and the valve core sleeve 509. The sensing rod 506 has a larger diameter at the rear end than at the front end and cannot pass through the bore of the valve core sleeve 509. The limiting ring 511 is a cup-shaped structure, the cup opening faces the valve core sleeve 509, and the rear end of the induction rod 506 is enveloped in the cup, so that the rear end of the induction rod can only move between the cup bottom of the cup-shaped structure and the valve core sleeve 509. The cup bottom faces the pump outlet port, and a small hole is formed in the cup bottom, so that the pump outlet end 102 can be communicated with the induction rod 506. The bottom end of the limiting ring 511 is provided with an elastic retainer ring 512 for limiting the movement of the limiting ring 511. The pump body is equipped with end cap 501 in the one side of pump mouth dorsad, end cap 501 adopts threaded connection on the pump body 1, and is provided with sealing washer 503 between the pump body inner wall. The one end that end cap 501 is towards pump export sets up the blind hole, be provided with spring 502 in the blind hole, spring 502 one end with end cap blind hole ground contact, the other end with cut off steel ball 504 contact. The blocking steel ball 504 is disposed between the valve seat 507 and the spring 502, and is in contact with the valve seat 507. And a valve seat sealing surface is arranged at the contact part of the valve seat 507 and the partition steel ball 504.

Furthermore, an annular groove is arranged on the outer diameter of the valve seat 507 of the low-pressure shielding device 5, the annular groove is communicated with a pump inlet through a low-pressure shielding

device discharge hole

104, and 4 small holes are uniformly distributed in the radial direction of the bottom of the annular groove and communicated with an inner hole of the valve seat 507. The front section of the induction rod 506 is divided into two sections, namely an induction section and a force transmission section, the force transmission section is close to the partition steel ball 504, and the induction section is close to the rear end of the induction rod 506. The diameter of the force transmission section is smaller than that of the inner hole of the valve seat 507, and an annular flow space is formed between the force transmission section and the inner wall of the valve seat 507. The annular flow space may communicate the low-pressure shield discharge hole 104 and the shield communication hole 103.

Further, a partition seal 505 between the valve seat 507 and the pump inner wall is provided between the low pressure shield drain hole 104 and the shield communication hole 103, and a seal surface between the partition steel ball 504 and the valve seat 507 is provided between the low pressure shield drain hole 104 and the shield communication hole 103. When the pump outlet pressure is lower than the set value of the spring, the low-pressure shielding device discharge hole 104 and the shielding device communication hole 103 are isolated, and the low-pressure piston and the high-pressure piston work simultaneously.

In the use process, the manual upward-pulling lever 203 drives the piston rod 204 to move upwards, the pressure of the high-pressure cavity 210 and the low-pressure cavity 211 is reduced, the inlet check valve of the high-pressure/low-pressure check valve set 3/4 is opened, and a medium enters the piston cavity through the check valve inlet flow passage hole 107/108 to finish medium suction. When the lever 203 is manually pressed down, the piston rod 204 is driven to move downwards, the pressure of the piston cavity 210/211 is increased, the outlet check valve of the high-pressure/low-pressure check valve set 3/4 is opened, the inlet check valve is closed, and a medium enters the pump outlet end 102 through the check valve outlet flow passage hole 113/114/115 and flows out, so that the medium is discharged.

When the pressure of the pump outlet 102 is lower than a set value, the spring 502 pushes the steel ball 504 against the valve core 507, and the separation steel ball 504 and the valve seat 507 form a seal to separate the low-pressure piston cavity 211 and the discharge passage 104. When the pressure of the pump outlet 102 reaches a certain value, the sensing rod 506 pushes away the separation steel ball 504 under the action of the pressure, the separation steel ball 504 and the valve seat 507 are separated from a sealing state, the low-pressure piston cavity 211 is communicated with the discharge passage 104, and the low-pressure piston is shielded. When the pressure of the pump outlet 102 exceeds a certain limit value, the sensing rod 506 of the low-pressure shielding device 5 pushes the steel ball 504 to move under the action of the outlet pressure, and when the steel ball 504 is separated from the sealing surface of the valve core 507, the shielding device communication hole 103 is communicated with the inner cavity of the valve core 507. Meanwhile, the shield communication hole 103 communicates with the low pressure flow channel hole 110. When the piston rod 204 moves downwards, the pressure in the low pressure piston cavity 211 increases to force the medium to enter the inner cavity of the valve core 507 of the low pressure shielding device 5 through the shielding device communicating hole 103, then enter the shielding device discharge hole 104 through the annular communicating gap between the sensing rod 506 and the inner cavity of the valve core 507, and finally communicate with the pump inlet flow passage hole 105 and the inlet end 101, and the pressure in the low pressure piston cavity 211 is directly discharged, and the low pressure piston is shielded.

The utility model discloses to use the manual hydraulic pump of single stroke one-level piston, optimize the structure and upgrade for the doublestage hydraulic pump that uses high-low pressure two-stage piston work, two-stage piston simultaneous working when the low pressure is filled the notes has improved greatly and has filled notes efficiency, has reduced operating personnel's operation intensity of labour.

The above description is only for the purpose of illustrating the technical content of the present invention by way of example, so as to facilitate the understanding of the reader, but does not represent that the embodiments of the present invention are limited thereto, and any technical extension or re-creation according to the present invention is protected by the present invention.

Claims

1. The utility model provides a manual hydraulic pump of high pressure doublestage, its characterized in that, includes the pump body, pump head subassembly, high pressure check valve subassembly, low pressure check valve subassembly and low pressure shield assembly, the pump body is the tetragonal structure, and the pump head subassembly is installed on the pump body, high pressure check valve subassembly, low pressure shield assembly cartridge are internal at the pump, shield assembly intercommunicating pore, low pressure shield assembly discharge flow path hole, pump inlet flow path hole, check valve inlet flow path hole, high pressure flow path hole, low pressure flow path hole and check valve outlet flow path hole have been seted up to pump body inside.

2. The high pressure dual stage manual hydraulic pump of claim 1, wherein: the pump head component comprises a pump head, a lifting lug, a pull rod, a lever, a piston rod, a connecting seal ring, a rod isolation seal, a body isolation seal, a high-pressure piston rod seal and a low-pressure piston rod seal, the pump head is of a hollow cylinder structure and is connected to the pump body through a thread at one end, the root of the thread is provided with a connecting seal ring, the head of the threaded end of the pump head is provided with a boss, the end surface of the boss is in contact positioning with the bottom surface of the pump body thread, a body isolation seal is arranged between the end surface of the boss and the pump body, the diameter of the boss is smaller than the small diameter of the pump body thread, an annular circulation channel is formed between the piston rod and the pump body, the piston rod penetrates through the hollow cavity of the pump body, part of the piston rod enters the inner cavity of the pump body, a rod isolation seal is arranged between the piston rod and the pump head, the piston rod, the pump body and the pump head enclose a piston cavity, the piston cavity is divided into a high-pressure piston cavity and a low-pressure piston cavity by the rod isolation seal and the body isolation seal.

3. The high pressure dual stage manual hydraulic pump of claim 2, wherein: the piston rod end and the lever are hinged through a pin shaft, the middle section of the piston rod penetrates through the hollow cavity of the pump head, the front section of the piston rod penetrates through the cavity of the pump head and enters the inner cavity of the pump body, a guide ring is arranged between the inner cavity of the pump head and the piston rod and is arranged at a position, close to the piston rod end, of the middle section of the piston rod, a snap ring is arranged on the outer side of the guide ring and limits the guide ring to move towards the outer side of the pump head, a low-pressure piston seal is arranged between the middle section of the piston rod and the pump body and is arranged on one side, close to the middle section of the piston rod front section, a high-pressure piston rod seal is arranged between the piston rod front section of the piston rod and the pump body, a, The pump head, the high-pressure piston rod seal and the space formed between the front sections of the piston rods are high-pressure piston cavities, and the space formed between the rod isolation seal, the piston rods, the pump head and the low-pressure piston seal is a low-pressure piston cavity.

4. The high pressure dual stage manual hydraulic pump of claim 3, wherein: the pump head is provided with an inclined hole which is communicated with the low-pressure piston cavity and the annular circulation channel.

5. The high pressure dual stage manual hydraulic pump of claim 3, wherein: the diameter of the front section of the piston rod is smaller than that of the middle section of the piston rod.

6. The high pressure dual stage manual hydraulic pump of claim 4, wherein: the pump body interpolation is equipped with two check valves of high pressure check valve group and low pressure check valve group, two check valve groups all include entry check valve and export check valve, be provided with low pressure runner hole on the pump body, low pressure runner hole intercommunication low pressure check valve group with annular circulation passageway, and then make low pressure check valve with low pressure piston chamber intercommunication, high pressure check valve pass through a intercommunicating pore on the pump body with high pressure piston chamber intercommunication.

7. The high pressure dual stage manual hydraulic pump of claim 1, wherein: the low-pressure shielding device comprises a plug, a spring, a steel ball, a valve seat, a valve core sleeve, an induction rod, a limiting ring and an elastic retainer ring, the components are arranged on the same axis coincident with the central line of the pump outlet circulation hole, the pump outlet circulation hole is a step hole, the valve seat is arranged at the bottom of the step hole and is contacted with the step surface, a separation sealing ring is arranged between the valve seat and the hole wall of the step hole, the valve core sleeve is arranged in the pump outlet circulation hole, one end of the valve core sleeve is tightly attached to the valve seat, a sealing ring is arranged between the valve core sleeve and the hole wall of the pump outlet circulation hole, the valve seat and the valve core sleeve are both of a hollow structure, the front end of the induction rod is arranged in inner holes of the valve core sleeve and the valve seat in a penetrating manner, a sealing ring is arranged between the front section of the induction rod and, the cup mouth faces to the valve core sleeve, the rear end of the induction rod is enveloped in the cup, so that the rear end of the induction rod can only move between the cup bottom of the cup-shaped structure and the valve core sleeve, the cup bottom of the cup-shaped structure faces the outlet port of the pump, the cup bottom is provided with a small hole, so that the outlet end of the pump can be communicated with the induction rod, the bottom end of the limiting ring cup is provided with an elastic retainer ring for limiting the movement of the limiting ring, a plug is arranged on one surface of the pump body, which is back to the outlet of the pump, the plug is connected on the pump body by screw threads, a sealing ring is arranged between the pump body and the inner wall of the pump body, a blind hole is arranged at one end of the choke plug facing the outlet of the pump, a spring is arranged in the blind hole, one end of the spring is contacted with the ground of the blind hole of the plug, the other end of the spring is contacted with the partition steel ball, the partition steel ball is arranged between the valve seat and the spring and is in contact with the valve seat, and a valve seat sealing surface is arranged at the position, in contact with the partition steel ball, of the valve seat.

8. The high pressure dual stage manual hydraulic pump of claim 7, wherein: the annular groove is arranged on the outer diameter of a valve seat of the low-pressure shielding device and communicated with a pump inlet through a low-pressure shielding device discharge hole, 4 small holes are uniformly distributed in the radial direction of the bottom of the annular groove and communicated with a valve seat inner hole, the front section of the sensing rod is divided into two sections, a sensing section and a force transmission section, the force transmission section is close to the partition steel ball, the sensing section is close to the rear end of the sensing rod, the diameter of the force transmission section is smaller than that of the valve seat inner hole, an annular circulation space is formed between the sensing section and the inner wall of the valve seat, and the annular circulation space can be communicated with the low-pressure shielding device discharge hole and the shielding.

9. The high pressure dual stage manual hydraulic pump of claim 7 or claim 8, wherein: the partition sealing ring between the valve seat and the inner wall of the pump is arranged between the low-pressure shielding device discharge hole and the shielding device communicating hole, the sealing surface between the partition steel ball and the valve seat is arranged between the low-pressure shielding device discharge hole and the shielding device communicating hole, when the pressure of the pump outlet is lower than the set value of the spring, the low-pressure shielding device discharge hole and the shielding device communicating hole are partitioned, and the low-pressure piston and the high-pressure piston work simultaneously.

10. The high pressure dual stage manual hydraulic pump of claim 7 or claim 8, wherein: the diameter of the inner hole of the valve seat is larger than the diameter of the induction section of the induction rod, when the pressure of the outlet of the pump is larger than the set pressure of the spring, the induction rod can move to the partition steel ball through the inner hole of the valve seat under the action of pressure and push away the partition steel ball, so that the discharge hole of the low-pressure shielding device is communicated with the communication hole of the shielding device, the cavity of the low-pressure piston is communicated with the inlet end of the pump, the diameter of a sealing surface between the valve seat and the partition steel ball is equal to the diameter of the inner hole of the valve seat and is larger than the diameter of the induction section of the induction rod, the pressure of the cavity of the low-pressure piston acts on the partition steel ball through the communication hole of the shielding device when the rocker of the lower pressure pump is pressurized in operation before the low-pressure shielding device is shielded, meanwhile, the pressure of the cavity of, the partition steel ball can not be pushed away, so that the low-pressure piston is prevented from being shielded in the process of pressurizing the force by an operator, and the phenomenon that the operator falls down due to the fact that the counterforce of the pump is suddenly reduced in the process of pressurizing the force by the operator is avoided.