CN114962370B

CN114962370B - Bidirectional variable damping one-way valve

Info

Publication number: CN114962370B
Application number: CN202210351436.XA
Authority: CN
Inventors: 苗国华; 迟峰; ***; 刘淑强
Original assignee: Shandong Lingong Construction Machinery Co Ltd
Current assignee: Shandong Lingong Construction Machinery Co Ltd
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2023-09-22
Anticipated expiration: 2042-04-02
Also published as: CN114962370A

Abstract

The invention discloses a bidirectional variable damping one-way valve, and belongs to the field of engineering machinery. The valve seat I and the valve seat II are respectively provided with a stepped oil duct for oil circulation, the two stepped oil ducts are communicated, a one-way valve core is respectively arranged in the two stepped oil ducts, a valve core oil duct communicated with the stepped oil duct is arranged on the one-way valve core, one opposite ends of the two one-way valve cores are provided with elastic mechanisms, one ends of the two one-way valve cores, which are far away from each other, are respectively provided with a sealing surface matched with the stepped platform of the stepped oil duct, and one side, close to the sealing surface, of the two one-way valve cores is respectively provided with an orifice and more than one oil hole communicated with the stepped oil duct. The invention has simple structure, stable operation and high reliability, can provide corresponding relations between two-way different differential pressures and flow for the one-way valve, thereby realizing accurate control of the speed of the working device and being suitable for the working device with higher operation accuracy requirement. The invention is mainly used for engineering mechanical equipment.

Description

Bidirectional variable damping one-way valve

Technical Field

The invention belongs to the field of engineering machinery, and particularly relates to a bidirectional variable damping one-way valve.

Background

At present, when engineering mechanical equipment is operated, a driver controls the opening degree of a valve core of a main control valve through a pilot handle, so that the speed of an executing element is controlled. Some special equipment, such as pile drivers, building dismantling machines, excavator hoisting working conditions and the like, have high requirements on the operation accuracy of the excavator working device, and meanwhile, the traditional control mode cannot accurately control the speed of the working device, so that safety accidents are easy to cause. The traditional technical scheme is that the purpose of accurate micro-operation is achieved by adding orifices. According to the calculation formula of the flow and pressure relation of the orificeUnder the condition of fixed throttle aperture, the relationship between flow and pressure difference is a fixed corresponding relationship, and the fixed corresponding relationship can not be accurately controlled, such as the corresponding relationship between flow and pressure difference with different requirements under the conditions of ascending and descending of a movable arm.

Disclosure of Invention

The invention aims to solve the technical problems that: the utility model provides a overcome the not enough of prior art, provides a two-way variable damping check valve, its simple structure, steady operation, reliability are high, can provide two-way different differential pressure and flow corresponding relation for the check valve to realize the speed of accurate control working device, be applicable to the higher working device of operation accuracy requirement.

The bidirectional variable damping one-way valve comprises a first valve seat and a second valve seat which are fixedly connected, wherein stepped oil channels for oil circulation are respectively arranged in the first valve seat and the second valve seat, the two stepped oil channels are communicated, a one-way valve core is respectively arranged in the two stepped oil channels, a valve core oil channel communicated with the stepped oil channels is arranged on the one-way valve core, an elastic mechanism is arranged at one opposite end of the two one-way valve cores, a sealing surface matched with the stepped platform of the stepped oil channels is respectively arranged at one end of the two one-way valve cores, which is far away from the two one end of the two one-way valve cores, and an orifice and more than one oil hole which are communicated with the stepped oil channels are respectively arranged at one side of the two one-way valve cores, which is close to the sealing surface. The orifices on the two unidirectional valve cores can be processed into different apertures during processing, so that corresponding relation curves of different flow pressures are provided for the two directions of the unidirectional valve, the unidirectional valve cores can be processed in batches according to different orifice aperture types, and when the unidirectional valve core is used, the unidirectional valve core can be directly replaced according to specific conditions.

Preferably, the throttle hole is communicated with the oil hole, the throttle hole is an axial hole, and the oil hole is a radial hole. The oil flowing direction in the throttle hole is consistent with the stepped oil duct, and the oil flowing direction in the oil hole is perpendicular to the stepped oil duct.

Preferably, the stepped oil duct comprises an oil port, a first hole and a second hole which are coaxially and sequentially communicated, and the sealing surface is matched with a stepped platform between the first hole and the second hole. The elastic mechanism can enable the sealing surfaces of the two unidirectional valve cores to be elastically attached to the hole one, so that the tightness is ensured.

Preferably, the unidirectional valve core is arranged at Kong Erna, the unidirectional valve core further comprises an outer circular surface and an end surface, the end surface is arranged at one end far away from the sealing surface, and a plurality of pressure equalizing grooves are formed in the outer circular surface. The outer circular surface and the second hole can slide relatively, the outer circular surface plays a role in guiding, and the pressure equalizing groove ensures that the circumferential pressure in the second hole is equalized without clamping the valve.

Preferably, the spool oil channels are axial holes, the spool oil channels are arranged in the unidirectional spools, the spool oil channels are respectively communicated with the throttling holes and the oil holes, and the elastic mechanism is arranged in the spool oil channels of the two unidirectional spools.

Preferably, the opposite ends of the two unidirectional valve cores are provided with mounting seats, two ends of the elastic mechanism are respectively matched with the two mounting seats, and the outer circular surface of the unidirectional valve core is provided with more than one valve core oil passage through milling grooves. The valve core oil duct is manufactured in a groove milling mode, and processing is convenient.

Preferably, a check ring is arranged between the two unidirectional valve cores, a through hole is arranged on the check ring, the elastic mechanism is a spring, and the elastic mechanism penetrates through the through hole. The check ring is additionally arranged, the check ring plays a limiting role, the check valve core in the second valve seat can be prevented from entering the stepped oil duct in the first valve seat, and the limit opening positions of the two check valve cores are limited, so that the coaxiality requirement of the stepped oil ducts on two sides is reduced, the processing and assembling difficulty is reduced, the production cost is reduced, and the reliability is enhanced.

Preferably, a check ring is arranged between the two unidirectional valve cores, elastic mechanisms are respectively arranged on two sides of the check ring, each elastic mechanism is a spring, one end of each elastic mechanism abuts against the corresponding check ring, the other end of each elastic mechanism is matched with the corresponding unidirectional valve core, and more than one through hole communicated with the two stepped oil channels is formed in the check ring. Springs are respectively arranged on two sides of the check ring, and different opening pressures of the two unidirectional valve cores can be set through the two springs.

Preferably, one end of the second valve seat, which is close to the first valve seat, is provided with a step positioning hole coaxial with the step oil duct, the step positioning hole comprises a large positioning hole and a small positioning hole, an internal thread is arranged in the small positioning hole, the first valve seat is provided with a large shaft surface and a small shaft surface coaxial with the step oil duct, the small shaft surface is provided with an external thread matched with the internal thread, the large shaft surface is matched with the large positioning hole to position so as to ensure the coaxiality of the second holes on the two valve seats, sealing grooves are respectively arranged on the large shaft surface and the outer end surface of the first valve seat, which is close to the second valve seat, and sealing pieces are arranged in the sealing grooves.

Preferably, one end of the valve seat I, which is close to the valve seat II, is provided with a step positioning table coaxial with the step oil duct, the step positioning table comprises a large positioning table and a small positioning table, one end of the large positioning table, which is far away from the valve seat II, is provided with a sealing groove, a sealing element is arranged in the sealing groove, the outer circle of the large positioning table is provided with an external thread, the valve seat II is internally provided with a positioning hole I and a positioning hole II which are coaxial with the step oil duct, the positioning hole I is internally provided with an internal thread matched with the external thread, and the positioning hole II is matched with the small positioning table for positioning. So as to ensure the coaxiality of the second holes on the two valve seats.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, two unidirectional valve cores with different orifice diameters are additionally arranged in the unidirectional valve, and two different flow and pressure difference corresponding relations can be provided for two sides of the unidirectional valve, so that the flow and speed corresponding relations of two conditions of lifting and lowering the movable arm are accurately controlled, and the purpose of accurate micro-operation is achieved;

2. the sealing surface of the inclined surface structure is additionally arranged on the one-way valve, and the sealing surface is elastically attached to the stepped platform of the stepped oil duct through the elastic mechanism, so that the sealing performance of the one-way valve core is improved on the basis of reducing the processing difficulty;

3. the check ring is additionally arranged in the check valve, the check ring can play a limiting role, the check valve core in the second valve seat is prevented from entering the stepped oil duct in the first valve seat, and the limit opening positions of the two check valve cores are limited, so that the coaxiality requirement of the stepped oil ducts at two sides is reduced, the processing and assembling difficulties are reduced, the production cost is reduced, and the reliability of the check valve is enhanced.

Drawings

FIG. 1 is a schematic diagram of the present invention;

fig. 2 is a schematic structural view of embodiment 1;

fig. 3 is a schematic structural view of embodiment 2;

FIG. 4 is a schematic structural view of the check valve cartridge in embodiment 2 and embodiment 3;

FIG. 5 is a schematic diagram of the cooperation of the check valve core and the retainer ring when the check valve core is in the extreme open position;

fig. 6 is a schematic structural view of embodiment 3;

fig. 7 is a schematic structural view of embodiment 4;

FIG. 8 is a front view of the one-way valve cartridge of example 4;

FIG. 9 is a left side view of the one-way valve cartridge of example 4;

FIG. 10 is a schematic diagram of the first and second valve seats in embodiment 5;

FIG. 11 is a schematic structural view of embodiment 6;

fig. 12 is a schematic diagram of the structures of the first valve seat and the second valve seat in embodiment 6.

In the figure, 1, a valve seat I; 101. an oil port; 102. a first hole; 103. a second hole; 1001. a large axial surface; 1002. sealing grooves; 1003. a minor axial surface; 1004. a large positioning table; 1005. a small positioning table; 2. a one-way valve core; 201. an outer circumferential surface; 202. a pressure equalizing groove; 203. sealing surfaces; 204. an end face; 205. a valve core oil passage; 206. an orifice; 207. an oil hole; 208. a mounting base; 3. a seal; 4. an elastic mechanism; 5. a retainer ring; 51. a through hole; 6. a valve seat II; 601. a large positioning hole; 602. a small positioning hole; 603. positioning holes I; 604. and a positioning hole II.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

example 1

As shown in fig. 2, the bidirectional variable damping check valve comprises a first valve seat 1 and a second valve seat 6 which are fixedly connected, the first valve seat 1 and the second valve seat 6 can be fixedly connected through threads or flanges, stepped oil channels for oil circulation are respectively arranged in the first valve seat 1 and the second valve seat 6, the two stepped oil channels are communicated, a check valve core 2 is respectively arranged in the two stepped oil channels, a valve core oil channel 205 communicated with the stepped oil channels is arranged on the check valve core 2, an elastic mechanism 4 is arranged at one end of the two check valve cores 2 opposite to each other, a sealing surface 203 matched with the stepped platform of the stepped oil channels is respectively arranged at one end of the two check valve cores 2, an orifice 206 and an oil hole 207 which are respectively communicated with the stepped oil channels are respectively arranged at one side of the two check valve cores 2 close to the sealing surface 203, and the oil holes 207 can be one or a plurality of.

As shown in fig. 1, the orifices 206 on the two unidirectional valve cores 2 can be processed into different apertures during processing, and the calculation formula is calculated according to the flow rate and pressure relationship of the orificesWherein A is the cross-sectional area of the orifice, Q is the flow, C is the throttling coefficient, deltaP is the pressure difference between the front and the back of the orifice, ρ is the density, thus providing different flow pressure corresponding relation curves for the two sides of the check valve, the check valve core 2 can be processed in batches according to different aperture types of the orifice 206, and when in use, the check valve core 2 can be directly replaced according to specific conditions.

Example 2

As shown in fig. 4, the throttle hole 206 communicates with the oil hole 207, the throttle hole 206 is an axial hole, and the oil hole 207 is a radial hole, that is, the oil flowing direction in the throttle hole 206 is consistent with the stepped oil passage, and the oil flowing direction in the oil hole 207 is perpendicular to the stepped oil passage. As shown in fig. 3, the stepped oil duct includes an oil port 101, a hole one 102 and a hole two 103 which are coaxially and sequentially communicated, and a sealing surface 203 is matched with a stepped platform between the hole one 102 and the hole two 103. The elastic mechanism 4 can enable the sealing surfaces 203 of the two unidirectional valve cores 2 to be elastically attached to the first hole 102, so that the tightness is ensured.

The unidirectional valve core 2 is disposed in the second hole 103, as shown in fig. 4, the unidirectional valve core 2 further includes an outer circular surface 201 and an end surface 204, the end surface 204 is disposed at one end far away from the sealing surface 203, and a plurality of equalizing grooves 202 are disposed on the outer circular surface 201. The outer circular surface 201 and the second hole 103 can slide relatively, the outer circular surface 201 plays a guiding role, and the pressure equalizing groove 202 ensures that the circumferential pressure in the second hole 103 is equalized without blocking a valve.

The spool oil passages 205 are axial holes, and the spool oil passages 205 are provided in the one-way spool 2, the spool oil passages 205 are respectively communicated with the throttle holes 206 and the oil holes 207, and the elastic mechanism 4 is provided in the spool oil passages 205 of the two one-way spools 2. A check ring 5 is arranged between the two unidirectional valve cores 2, a through hole 51 is arranged on the check ring 5, the elastic mechanism 4 is a spring, the spring passes through the through hole 51, and two ends of the spring are respectively propped against inner end surfaces 204 of valve core oil channels 205 in the two unidirectional valve cores 2; the other steps are the same as in example 1.

The check ring 5 is additionally arranged, the check ring 5 plays a limiting role, the check valve core 2 in the valve seat II 6 can be prevented from entering the stepped oil duct in the valve seat I1, and the limit opening positions of the two check valve cores 2 are limited, so that the coaxiality requirements of the stepped oil ducts on two sides are reduced, the processing and assembling difficulty is reduced, the production cost is reduced, and the reliability is enhanced.

Example 3

As shown in fig. 6, a check ring 5 is arranged between two unidirectional valve cores 2, a check ring groove is arranged on the inner side wall of a hole two 103 on a valve seat 1 or a valve seat two 6, the check ring 5 is arranged in the check ring groove, two sides of the check ring 5 are respectively provided with an elastic mechanism 4, one end of the elastic mechanism 4 is propped against the check ring 5, the other end of the elastic mechanism 4 is propped against the inner end surface 204 of a valve core oil duct 205 in the unidirectional valve core 2, and one or more through holes 51 communicated with two stepped oil ducts are arranged on the check ring 5. Elastic mechanisms 4 are respectively arranged on two sides of the check ring 5, and different opening pressures can be set for the two unidirectional valve cores 2 through the two elastic mechanisms 4; the other steps are the same as in example 2.

Example 4

As shown in fig. 7 to 9, opposite ends of the two unidirectional valve spools 2 are respectively provided with a mounting seat 208, two ends of the elastic mechanism 4 are respectively matched with the two mounting seats 208, the outer circular surface 201 of the unidirectional valve spool 2 is provided with one or more valve spool oil passages 205 through milling grooves, in this embodiment four valve spool oil passages 205 are provided, and the valve spool oil passages 205 in this embodiment are communicated with the oil hole 207 through the second hole 103. The valve core oil duct 205 is manufactured in a groove milling mode, so that the processing is more convenient. In this embodiment, the structure of the unidirectional valve core 2 is changed, so that the outer circumferential surface 201 of the unidirectional valve core 2 is changed into a square-like structure after milling grooves, thereby being convenient for oil circulation, and the other is the same as that of embodiment 2 or embodiment 3.

Example 5

As shown in fig. 2 and 10, one end of the second valve seat 6, which is close to the first valve seat 1, is provided with a stepped positioning hole coaxial with the stepped oil duct, the stepped positioning hole comprises a large positioning hole 601 and a small positioning hole 602, an internal thread is arranged in the small positioning hole 602, the first valve seat 1 is provided with a large shaft surface 1001 and a small shaft surface 1003 coaxial with the stepped oil duct, the small shaft surface 1003 is provided with an external thread matched with the internal thread, the large shaft surface 1001 is matched with the large positioning hole 601 to position so as to ensure the coaxiality of the second holes 103 on the two valve seats, sealing grooves 1002 are respectively arranged on the outer end surfaces of the large shaft surface 1001 and the first valve seat 1, which are close to the second valve seat 6, and sealing pieces 3 are arranged in the sealing grooves 1002. In this embodiment, the retainer 5 is omitted, and the problem of ensuring coaxiality is achieved by the matching relationship between the first valve seat 1 and the second valve seat 6 through the shaft hole, otherwise the same as in embodiment 1 or embodiment 2 or embodiment 3 or embodiment 4.

Example 6

As shown in fig. 11 and 12, one end of the first valve seat 1, which is close to the second valve seat 6, is provided with a step positioning table coaxial with the step oil duct, the step positioning table comprises a large positioning table 1004 and a small positioning table 1005, one end of the large positioning table 1004, which is far away from the second valve seat 6, is provided with a sealing groove 1002, a sealing element 3 is arranged in the sealing groove 1002, the outer circle of the large positioning table 1004 is provided with an external thread, the second valve seat 6 is internally provided with a first positioning hole 603 and a second positioning hole 604 which are coaxial with the step oil duct, an internal thread matched with the external thread is arranged in the first positioning hole 603, and the second positioning hole 604 is matched with the small positioning table 1005 to be positioned so as to ensure the coaxiality of the second holes 103 on the two valve seats. In this embodiment, the retainer 5 is omitted, and the problem of ensuring coaxiality is achieved by the matching relationship between the first valve seat 1 and the second valve seat 6 through the shaft hole, otherwise the same as in embodiment 1 or embodiment 2 or embodiment 3 or embodiment 4.

The working process of the invention comprises the following steps:

for ease of explanation, the check valve element in the first valve seat 1 is denoted as a check valve element 21, the orifice on the check valve element 21 is denoted as an orifice a, and the check valve element in the second valve seat 6 is denoted as a check valve element 22, and the orifice on the check valve element 22 is denoted as an orifice b.

As shown in fig. 5, when hydraulic oil enters the second valve seat 6, the hydraulic oil enters the first hole 102 through the oil port 101 on the second valve seat 6, and when the oil pressure reaches the preset opening pressure of the elastic mechanism 4, the second check valve core 22 is opened, and the second check valve core 22 is matched with the second hole 103 through the outer circular surface 201 to perform relative movement to the left side. When the end face 204 is attached to the right end face of the 5 check ring, the second check valve core 22 reaches the opening stateAt the maximum position, as shown in fig. 5, the outer circular surface 201 does not enter the second hole 103 in the first valve seat 1, so that the coaxiality requirement of the first valve seat 1 and the second hole 103 in the second valve seat 6 is reduced, the processing and assembling difficulties are reduced, the cost is reduced, and the reliability is enhanced. The hydraulic oil hole I102 and the hole II 103 sequentially enter the oil hole 207 and the valve core oil channel 205 and then enter the valve core oil channel 205 in the one-way valve core I21, at the moment, under the action of spring force and oil pressure, the sealing surface 203 on the one-way valve core I21 is in a fit sealing state with the hole I102 on the valve seat I1, hydraulic oil enters the hole I102 through the orifice a, finally flows out through the oil hole 101, and at the moment, according to the formula relationWherein A1 is the cross-sectional area of the orifice a, and a corresponding relation 1 between differential pressure and flow is formed. The oil ports 101 on the first valve seat 1 and the second valve seat 6 are fixedly connected with other parts.

When hydraulic oil enters the first valve seat 1, the principle is the same as above, the hydraulic oil enters the first valve seat 102 through the oil port 101, when the oil pressure reaches the preset opening pressure of the elastic mechanism 4, the first unidirectional valve core 21 in the first valve seat 1 is opened, the first unidirectional valve core 21 is matched with the second valve seat 103 through the outer circular surface 201, the first unidirectional valve core 21 moves relatively to the right side, the outer circular surface 201 plays a guiding role, and the pressure equalizing groove 202 ensures that the first unidirectional valve core 21 is balanced in circumferential pressure and does not clamp the valve. When the end surface 204 is attached to the left end surface of the retainer 5, the first check valve element 21 reaches the maximum opening position. At this time, the hydraulic oil enters the hole two 103, the oil hole 207 on the one-way valve core one 21 and the valve core oil channel 205 in sequence through the hole one 102, then enters the valve core oil channel 205 on the one-way valve core two 22, at this time, under the action of spring force and oil pressure, the sealing surface 203 on the one-way valve core two 22 and the hole one 102 on the valve seat two 6 are in a fitting sealing state, the hydraulic oil enters the hole one 102 through the throttle b on the one-way valve core two 22, finally flows out through the oil port 101 on the valve seat two 6, at this time according to the formula relationWherein A2 is the cross-sectional area of the orifice b on the second unidirectional valve core 22, and forms a corresponding relationship 2 between differential pressure and flow.

Claims

1. A bidirectional variable damping one-way valve is characterized in that: including fixed connection's disk seat one (1) and disk seat two (6), be equipped with the ladder oil duct that supplies the fluid circulation in disk seat one (1) and disk seat two (6) respectively, two ladder oil ducts are linked together, be equipped with one-way case (2) in two ladder oil ducts respectively, be equipped with on one-way case (2) with the case oil duct (205) of ladder oil duct intercommunication, the one end that two one-way cases (2) are relative is equipped with elastic mechanism (4), the one end that two one-way cases (2) kept away from is equipped with respectively with ladder platform complex sealing surface (203) of ladder oil duct, one side that is close to sealing surface (203) on two one-way cases (2) is equipped with orifice (206) and more than one oilhole (207) that are linked together with the ladder oil duct respectively.

2. The bi-directional variable damping check valve according to claim 1, wherein: the throttle hole (206) is communicated with the oil hole (207), the throttle hole (206) is an axial hole, and the oil hole (207) is a radial hole.

3. The bi-directional variable damping check valve according to claim 1, wherein: the stepped oil duct comprises an oil port (101), a first hole (102) and a second hole (103) which are coaxially and sequentially communicated, and a sealing surface (203) is matched with a stepped platform between the first hole (102) and the second hole (103).

4. A bi-directional variable damping check valve according to claim 3, wherein: the one-way valve core (2) is arranged in the second hole (103), the one-way valve core (2) further comprises an outer circular surface (201) and an end surface (204), the end surface (204) is arranged at one end far away from the sealing surface (203), and a plurality of pressure equalizing grooves (202) are formed in the outer circular surface (201).

5. The bi-directional variable damping check valve according to claim 4, wherein: the spool oil duct (205) is an axial hole, the spool oil duct (205) is arranged in the unidirectional spool (2), the spool oil duct (205) is respectively communicated with the throttle hole (206) and the oil hole (207), and the elastic mechanism (4) is arranged in the spool oil duct (205) of the two unidirectional spools (2).

6. The bi-directional variable damping check valve according to claim 4, wherein: two opposite ends of the unidirectional valve core (2) are provided with mounting seats (208), two ends of the elastic mechanism (4) are respectively matched with the two mounting seats (208), and more than one valve core oil duct (205) is arranged on the outer circular surface (201) of the unidirectional valve core (2) through milling grooves.

7. The bi-directional variable damping check valve according to any one of claims 1-6, wherein: a check ring (5) is arranged between the two unidirectional valve cores (2), a through hole (51) is arranged on the check ring (5), and the elastic mechanism (4) passes through the through hole (51).

8. The bi-directional variable damping check valve according to any one of claims 1-6, wherein: a check ring (5) is arranged between the two unidirectional valve cores (2), elastic mechanisms (4) are respectively arranged on two sides of the check ring (5), one ends of the two elastic mechanisms (4) are propped against the check ring (5), the other ends of the elastic mechanisms (4) are matched with the unidirectional valve cores (2), and more than one through hole (51) communicated with the two stepped oil channels is formed in the check ring (5).

9. The bi-directional variable damping check valve according to any one of claims 1-6, wherein: the one end that is close to disk seat one (1) on disk seat two (6) is equipped with the ladder locating hole coaxial with the ladder oil duct, and the ladder locating hole includes big locating hole (601) and little locating hole (602), is equipped with the internal thread in little locating hole (602), is equipped with on disk seat one (1) with the coaxial big axial face (1001) of ladder oil duct and little axial face (1003), be equipped with on little axial face (1003) with internal thread complex external screw thread, big axial face (1001) and big locating hole (601) cooperation location are equipped with seal groove (1002) on the outer terminal surface that is close to disk seat two (6) in big axial face (1001) and disk seat one (1) respectively, install sealing member (3) in seal groove (1002).

10. The bi-directional variable damping check valve according to any one of claims 1-6, wherein: the one end that disk seat one (1) is close to disk seat two (6) is equipped with the ladder location platform coaxial with the ladder oil duct, the ladder location platform includes big location platform (1004) and little location platform (1005), the one end of far away disk seat two (6) on big location platform (1004) is equipped with seal groove (1002), be equipped with sealing member (3) in seal groove (1002), the excircle of big location platform (1004) is equipped with the external screw thread, be equipped with in disk seat two (6) with coaxial locating hole one (603) and locating hole two (604) of ladder oil duct, be equipped with in locating hole one (603) with external screw thread complex internal screw thread, locating hole two (604) are fixed a position with little location platform (1005) cooperation.