阅读说明：本技术 一种换挡助力气缸 (Gear shifting power-assisted cylinder ) 是由 张少华 李剑强 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种换挡助力气缸,包括主缸筒,主缸筒的左端设置有端盖,端盖上设置有放气孔；主缸筒的右端连接有副缸筒；主缸筒内设置有活塞组件,活塞组件包含中空活塞和伸出中空活塞左端的中空活塞杆,中空活塞的右端连接有中空驱动轴；中空活塞的外侧壁设置有第一环形凹槽,主缸筒的筒壁中部设置有与第一环形凹槽连通的第一进气孔,第一环形凹槽与主缸筒内壁形成环形气体通道,中空活塞上设置有连通第一环形凹槽与中空活塞内部的第二进气孔；中空活塞上设置有分别与左室和右室连通的左出气孔和右出气孔。本发明技术方案相对于现有技术而言,气动换挡助力系统能够使汽车变速器换挡轻便、平稳,换挡操作舒适,减轻驾驶员的工作强度。(The invention discloses a gear shifting power-assisted cylinder which comprises a main cylinder barrel, wherein an end cover is arranged at the left end of the main cylinder barrel, and an air vent is arranged on the end cover; the right end of the main cylinder barrel is connected with an auxiliary cylinder barrel; a piston assembly is arranged in the main cylinder barrel, the piston assembly comprises a hollow piston and a hollow piston rod extending out of the left end of the hollow piston, and the right end of the hollow piston is connected with a hollow driving shaft; the outer side wall of the hollow piston is provided with a first annular groove, the middle part of the cylinder wall of the main cylinder barrel is provided with a first air inlet communicated with the first annular groove, the first annular groove and the inner wall of the main cylinder barrel form an annular gas channel, and the hollow piston is provided with a second air inlet communicated with the first annular groove and the interior of the hollow piston; the hollow piston is provided with a left air outlet hole and a right air outlet hole which are respectively communicated with the left chamber and the right chamber. Compared with the prior art, the pneumatic gear shifting power assisting system has the advantages that the gear shifting of the automobile transmission is light and stable, the gear shifting operation is comfortable, and the working strength of a driver is reduced.)

1. The gear shifting power-assisted cylinder is characterized by comprising a main cylinder barrel (1), wherein an end cover (2) is arranged at the left end of the main cylinder barrel (1), and an air vent (10) is arranged on the end cover (2); the right end of the main cylinder barrel (1) is connected with an auxiliary cylinder barrel (3); a piston assembly (4) is arranged in the main cylinder barrel (1), the piston assembly (4) comprises a hollow piston (401) and a hollow piston rod (402) extending out of the left end of the hollow piston (401), the hollow piston (401) divides the interior of the main cylinder barrel (1) into a left chamber and a right chamber, and the right end of the hollow piston (401) is connected with a hollow driving shaft (5);

a first annular groove (408) is formed in the outer side wall of the hollow piston (401), a first air inlet hole (101) communicated with the first annular groove (408) is formed in the middle of the cylinder wall of the main cylinder barrel (1), an annular gas channel is formed by the first annular groove (408) and the inner wall of the main cylinder barrel (1), and a second air inlet hole (403) communicated with the first annular groove (408) and the interior of the hollow piston (401) is formed in the hollow piston (401);

a left air outlet hole (404) and a right air outlet hole (405) which are respectively communicated with the left chamber and the right chamber are formed in the hollow piston (401);

a control core shaft (6) is arranged in the hollow driving shaft (5); a bidirectional valve assembly (7) is arranged in the hollow piston (401), the control mandrel (6) moves left along the axial direction, the bidirectional valve assembly (7) opens a channel between the interior of the hollow piston (401) and the right chamber, and the hollow piston (401) drives the hollow driving shaft (5) to move left;

the control mandrel (6) moves to the right along the axial direction, the two-way valve assembly (7) opens a channel between the interior of the hollow piston (401) and the left chamber, and the hollow piston (401) drives the hollow driving shaft (5) to move to the right.

2. The gear shifting power-assisted cylinder according to claim 1, characterized in that the bidirectional valve assembly (7) comprises a double-layer sleeve (701), a partition plate is arranged between an inner cylinder and an outer cylinder of the double-layer sleeve (701), the double-layer sleeve (701) is slidably sleeved on the operating mandrel (6), a left spring (702) is sleeved on the left side of the double-layer sleeve (701), and a left sealing ring (703) is sleeved on the left end of the left spring (702); a right spring (704) is sleeved on the right side of the double-layer sleeve (701), and a right sealing ring (705) is sleeved on the right end of the right spring (704); the inner wall of the hollow piston (401) is provided with a left sealing ring (406) which is abutted against the left sealing ring (703), and the inner wall of the hollow piston (401) is provided with a right sealing ring (407) which is abutted against the right sealing ring (705); the control core shaft (6) is fixedly connected with a left top ring (8) positioned on the left side of the left sealing ring (703) and a right top ring (9) positioned on the right side of the right sealing ring (705); the distance between the right end of the left top ring (8) and the left end of the right top ring (9) is larger than the distance between the left sealing ring (406) and the right sealing ring (407).

3. The gear shifting assisting cylinder according to claim 1, wherein three circles of second annular grooves (501) are formed in the hollow driving shaft (5) inside the auxiliary cylinder barrel (3), a mounting hole (301) along the radial direction of the middle second annular groove (501) is formed in the auxiliary cylinder barrel (3), a support spring (302) and a support pillar (303) are sequentially arranged in the mounting hole (301) from outside to inside, and one end, in contact with the annular grooves, of the support pillar (303) is spherical.

4. The shift boosting cylinder according to claim 1, characterized in that the center of the operating mandrel (6) is provided with a blind exhaust hole (601) extending from the left end to the right top ring (9), and the side wall of the blind exhaust hole (601) is provided with an exhaust hole (602) arranged on the operating mandrel (6) and communicated with the left chamber and the right chamber.

5. Gear shift assistance cylinder according to claim 2, characterised in that the left top ring (8) and the right top ring (9) are each fixed on the operating spindle (6) by means of a spring collar.

6. Gear assisted power cylinder according to claim 2, characterized in that the left sealing ring (406) is formed integrally with the hollow piston (401) and the right sealing ring (407) is fixedly connected to the inner wall of the hollow piston (401) by means of a spring collar.

7. Gear shift aid cylinder according to claim 1, characterised in that the right end of the hollow piston (401) is provided with an internal thread and the left end of the hollow drive shaft (5) is provided with an external thread matching the internal thread, the hollow piston (401) being in threaded connection with the hollow drive shaft (5).

8. The shift boosting cylinder according to claim 1, characterized in that a small sealing ring (11) matched with the operating mandrel (6) is arranged inside the hollow driving shaft (5), a first oil seal (12) is arranged outside the small sealing ring (11), and the first oil seal (12) is clamped and fixed in the hollow driving shaft (5) through a spring collar (13); a large sealing ring (14) matched with the hollow driving shaft (5) is arranged in the auxiliary cylinder barrel (3), a second oil seal (15) is arranged outside the large sealing ring (14), and the second oil seal (15) is clamped and fixed in the auxiliary cylinder barrel (3) through a spring clamp (13).

9. The shift boosting cylinder according to claim 8, wherein the small sealing ring (11) and the large sealing ring (14) are made of polytetrafluoroethylene.

10. The gear shifting power-assisted cylinder according to claim 1, further comprising four bolts, wherein the end cover (2), the main cylinder barrel (1) and the auxiliary cylinder barrel (3) are connected into a whole through the four bolts.

Technical Field

The invention relates to the field of automobile gearboxes, in particular to a gear shifting assisting cylinder.

Background

The function of the vehicle transmission is to change the torque and the rotation speed of the engine according to the requirements of the vehicle under different driving conditions, so that the vehicle has proper traction and speed, and simultaneously, the engine is kept to work in the most favorable working condition range, so that the vehicle has high dynamic performance and economic performance indexes. This is especially true for the critical component transmission assemblies of trucks. In the early mechanical transmission, the shifting mode is generally realized by adopting a slipping gear or a meshing sleeve, so that inconvenience is brought to operation, the clutch is manually stepped when the gear is shifted, and the rotating speed of the engine is regulated (the rotating speed of the engine is required to be reduced when the gear is shifted upwards, and the rotating speed of the engine is required to be increased when the gear is shifted downwards, namely the rotating speed of the engine is required to be increased, namely the accelerator is retracted or the accelerator is rolled up) to control the rotating speeds of an input end and an output end to achieve synchronization, so that the labor intensity and the tension of a driver are increased. In order to ensure that the end part of a gear is not impacted when the transmission needs to shift gears during the running of an automobile, and the gear is convenient, flexible and quick to operate, a lock pin type synchronizer or a lock ring type synchronizer is adopted in mechanical transmissions on modern automobiles, so that the acceleration and the running safety of the automobile can be improved. At present, synchronizers of various types of structures adopt a friction principle, namely, a certain friction force is generated on a friction conical surface of the synchronizer so as to obtain a certain friction torque to overcome the rotational inertia of an input end part, so that the rotating speeds of an input end and an output end reach a synchronous state in the shortest time, and light gear shifting and quick gear shifting are facilitated. The friction force and the friction torque to be generated on the friction conical surface of the synchronizer are obtained by the gear shifting force applied by a driver, the gear shifting force applied by the driver is large, the friction force and the friction torque generated between the friction conical surfaces of the synchronizer are large, the synchronization time and the gear shifting time are short, and therefore quick gear shifting can be achieved, otherwise, the rotating speeds of the input end and the output end cannot reach a synchronization state in a short time, and therefore quick gear shifting cannot be achieved, and the gear shifting time is prolonged. The long gear shifting time directly influences the acceleration and dynamic performance of the automobile and influences the normal running of the automobile. However, in the mechanical transmission configured for modern heavy-duty vehicles, because the input torque, the speed ratio and the gear are all larger and more than those of a transmission of a lighter vehicle, the transmission has more internal requirements and mass, and the rotational inertia of the input end of the synchronizer is increased greatly, so that when the transmission needs to be shifted during the running of the heavy-duty vehicle, a driver needs to apply a larger shifting force (the heavy-duty vehicle transmission generally has a force of about 5 kilograms) to achieve the purpose of fast shifting. However, in the whole driving process of the automobile, in order to adapt to various road conditions and working conditions, the gear shifting of the transmission is very frequent, and then the driver also frequently uses 5 kilograms of force to deal with the gear shifting, so that the labor intensity of the driver is inevitably increased, the driver is always in a fatigue state, and the automobile is extremely unsafe to drive.

Therefore, how to design a shift assisting device is a technical problem which needs to be solved by those skilled in the art at present.

Disclosure of Invention

In order to solve the technical problems, the invention mainly aims to provide a gear shifting assisting cylinder which can assist a driver in gear shifting operation of an automobile so as to reduce the gear shifting force of the driver and save the driver labor.

In order to achieve the above object, the present invention adopts the following technical solutions.

A gear shifting power-assisted cylinder comprises a main cylinder barrel, wherein an end cover is arranged at the left end of the main cylinder barrel, and an air vent is formed in the end cover; the right end of the main cylinder barrel is connected with an auxiliary cylinder barrel; a piston assembly is arranged in the main cylinder barrel, the piston assembly comprises a hollow piston and a hollow piston rod extending out of the left end of the hollow piston, the hollow piston divides the interior of the main cylinder barrel into a left chamber and a right chamber, and the right end of the hollow piston is connected with a hollow driving shaft; the outer side wall of the hollow piston is provided with a first annular groove, the middle part of the cylinder wall of the main cylinder barrel is provided with a first air inlet communicated with the first annular groove, the first annular groove and the inner wall of the main cylinder barrel form an annular gas channel, and the hollow piston is provided with a second air inlet communicated with the first annular groove and the interior of the hollow piston; the hollow piston is provided with a left air outlet hole and a right air outlet hole which are respectively communicated with the left chamber and the right chamber; a control core shaft is arranged in the hollow driving shaft; a bidirectional valve component is arranged in the hollow piston, the control mandrel moves left along the axial direction, the bidirectional valve component opens a channel between the interior of the hollow piston and the right chamber, and the hollow piston drives the hollow driving shaft to move left; the control core shaft moves rightwards along the axial direction, the two-way valve component opens a channel between the interior of the hollow piston and the left chamber, and the hollow piston drives the hollow driving shaft to move rightwards.

Further, the two-way valve assembly comprises a double-layer sleeve, a partition plate is arranged between an inner cylinder and an outer cylinder of the double-layer sleeve, the double-layer sleeve is slidably sleeved on the control core shaft, a left spring is sleeved on the left side of the double-layer sleeve, a left sealing ring is sleeved at the left end of the left spring, a right spring is sleeved on the right side of the double-layer sleeve, and a right sealing ring is sleeved at the right end of the right spring; the inner wall of the hollow piston is provided with a left sealing ring which is abutted against the left sealing ring, and the inner wall of the hollow piston is provided with a right sealing ring which is abutted against the right sealing ring; the control core shaft is fixedly connected with a left top ring positioned on the left side of the left sealing ring and a right top ring positioned on the right side of the right sealing ring; the distance between the right end of the left top ring and the left end of the right top ring is larger than the distance between the left sealing ring and the right sealing ring.

Furthermore, a hollow driving shaft located inside the auxiliary cylinder barrel is provided with three circles of second annular grooves, the auxiliary cylinder barrel is provided with a mounting hole along the radial direction of the middle second annular groove, a support spring and a support are sequentially arranged in the mounting hole from outside to inside, and one end, contacting with the annular grooves, of the support is spherical.

Furthermore, the center of the control core shaft is provided with an exhaust blind hole extending from the left end to the right top ring, and the side wall of the exhaust blind hole is provided with an exhaust hole communicated with the left chamber and the right chamber on the control core shaft.

Furthermore, the left top ring and the right top ring are fixed on the control core shaft through spring collars.

Furthermore, the left sealing ring and the hollow piston are integrally formed, and the right sealing ring is fixedly connected to the inner wall of the hollow piston through a spring retainer ring.

Further, the right-hand member of cavity piston is provided with the internal thread, and the left end of cavity drive shaft is provided with the external screw thread that matches with the internal thread, cavity piston and cavity drive shaft threaded connection.

Furthermore, a small sealing ring matched with the control core shaft is arranged in the hollow driving shaft, a first oil seal is arranged outside the small sealing ring, and the first oil seal is fixedly clamped in the hollow driving shaft through a spring retainer ring; a large sealing ring matched with the hollow driving shaft is arranged in the auxiliary cylinder barrel, a second oil seal is arranged outside the large sealing ring, and the second oil seal is fixedly clamped in the auxiliary cylinder barrel through a spring retainer ring.

Furthermore, the small sealing ring and the large sealing ring are made of polytetrafluoroethylene.

Furthermore, the end cover, the main cylinder barrel and the auxiliary cylinder barrel are connected into a whole through the four bolts.

Compared with the prior art, the pneumatic gear shifting power assisting system has the advantages that the gear shifting of the automobile transmission is light and stable, the gear shifting operation is comfortable, and the working strength of a driver is reduced.

Drawings

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

FIG. 1 is a perspective view of one embodiment of a shift assist cylinder of the present invention;

FIG. 2 is a schematic cross-sectional view of an embodiment of the shift assist cylinder of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a perspective view of the piston assembly and the bi-directional valve assembly;

FIG. 5 is a cross-sectional schematic view of the piston assembly and the bi-directional valve assembly;

in the above figures:

1, a main cylinder barrel; 101 a first air inlet hole; 2, end cover;

3, auxiliary cylinder barrels; 301 mounting holes; 302 a top post spring; 303, jacking a column;

4 a piston assembly; 401 a hollow piston; 402 a hollow piston rod; 403 second intake holes; 404 left air outlet hole; 405 a right air outlet; 406 a left sealing ring; 407 right sealing ring; 408 a first annular groove;

5 a hollow drive shaft; 501 a second annular groove;

6 operating the mandrel; 601 an exhaust blind hole; 602 exhaust holes;

7 a two-way valve assembly; 701 a double-layer sleeve; 702 a left spring; 703 a left sealing ring; 704 a right spring; 705 a right sealing ring;

8, a left top ring; 9, a right top ring; 10, air bleeding holes; 11 small sealing rings; 12 a first oil seal; 13 a spring collar; 14 large sealing rings; 15 second oil seal.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The invention can be implemented in a number of ways different from those described herein and similar generalizations can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

Referring to fig. 1 and 2, a shift boosting cylinder includes a main cylinder barrel 1, an end cover 2 is disposed at a left end of the main cylinder barrel 1, and an air vent 10 is disposed on the end cover 2; the right end of the main cylinder barrel 1 is connected with an auxiliary cylinder barrel 3; a piston assembly 4 is arranged in the main cylinder barrel 1, the piston assembly 4 comprises a hollow piston 401 and a hollow piston rod 402 extending out of the left end of the hollow piston 401, the hollow piston 401 divides the interior of the main cylinder barrel 1 into a left chamber and a right chamber, and the right end of the hollow piston 401 is connected with a hollow driving shaft 5; a first annular groove 408 is formed in the outer side wall of the hollow piston 401, a first air inlet 101 communicated with the first annular groove 408 is formed in the middle of the cylinder wall of the main cylinder barrel 1, an annular air channel is formed between the first annular groove 408 and the inner wall of the main cylinder barrel 1, and a second air inlet 403 communicated with the first annular groove 408 and the interior of the hollow piston 401 is formed in the hollow piston 401; the hollow piston 401 is provided with a left air outlet 404 and a right air outlet 405 which are respectively communicated with the left chamber and the right chamber; a control core shaft 6 is arranged in the hollow driving shaft 5; a two-way valve assembly 7 is arranged in the hollow piston 401, the control mandrel 6 moves leftwards along the axis, the two-way valve assembly 7 opens a channel between the inside of the hollow piston 401 and the right chamber, and the hollow piston 401 drives the hollow driving shaft 5 to move leftwards; the operating mandrel 6 moves to the right along the axial direction, the two-way valve assembly 7 opens a channel between the interior of the hollow piston 401 and the left chamber, and the hollow piston 401 drives the hollow driving shaft 5 to move to the right.

In the above embodiment, the operating spindle 6 is connected to the shift rocker arm, and the hollow drive shaft 5 is connected to the transmission. A two-way valve assembly 7 is provided within the hollow piston 401. The control mandrel 6 moves leftwards along the axial direction, an air channel between the hollow piston 401 and the right chamber can be opened, and compressed air enters the right chamber through the right air outlet 405, so that the hollow piston 401 is driven to move leftwards, and the hollow driving shaft 5 is driven to move leftwards. Similarly, the control core shaft 6 moves rightwards along the axial direction, and can drive the hollow driving shaft 5 to move rightwards. In the above process, the driver inputs a small force to the steering spindle 6, and finally outputs a large force in the same direction from the hollow drive shaft 5.

Further, referring to fig. 4 and 5, the bidirectional valve assembly 7 includes a double-layer sleeve 701, a partition plate is disposed between an inner cylinder and an outer cylinder of the double-layer sleeve 701, the double-layer sleeve 701 is slidably sleeved on the operating spindle 6, a left spring 702 is sleeved on the left side of the double-layer sleeve 701, a left sealing ring 703 is sleeved on the left end of the left spring 702, a right spring 704 is sleeved on the right side of the double-layer sleeve 701, and a right sealing ring 705 is sleeved on the right end of the right spring 704; the inner wall of the hollow piston 401 is provided with a left sealing ring 406 which is abutted against the left sealing ring 703, and the inner wall of the hollow piston 401 is provided with a right sealing ring 407 which is abutted against the right sealing ring 705; a left top ring 8 positioned on the left side of the left sealing ring 703 and a right top ring 9 positioned on the right side of the right sealing ring 705 are fixedly connected to the control mandrel 6; the distance between the right end of the left top ring 8 and the left end of the right top ring 9 is greater than the distance between the left seal ring 406 and the right seal ring 407.

In the above embodiment, the interior of the hollow piston 401 employs the two-way valve assembly 7 to achieve selective communication between the hollow piston 401 and the left or right chamber. The left side of the double-layer sleeve 701 is provided with a left spring 702 and a left sealing ring 703, the right side is provided with a right spring 704 and a right sealing ring 705, the inside of the hollow piston 401 is provided with a left sealing ring 406 matched with the left sealing ring 703, and the hollow piston is further provided with a right sealing ring 407 matched with the right sealing ring 705.

The working principle is as follows:

in a non-working state, under the action of the left spring 702 and the right spring 704, the left sealing ring 703 is in contact with the left sealing ring 406, the right sealing ring 705 is in contact with the right sealing ring 407, a closed space is formed inside the hollow piston 401, the left chamber and the right chamber are both communicated with the atmosphere, the inside of the hollow piston 401 is balanced, and the hollow piston 401 does not move leftwards or rightwards.

The working state is as follows: when the control mandrel 6 moves leftwards, the right top ring 9 pushes the right sealing ring 705 to separate the right sealing ring 705 from the right sealing ring 407, the interior of the hollow piston 401 is communicated with the right chamber, and compressed gas enters the right chamber to drive the hollow piston 401 to move leftwards and drive the hollow driving shaft 5 to move leftwards; similarly, the control mandrel 6 moves to the right to drive the hollow piston 401 to move to the right, and the hollow driving shaft 5 is driven to move to the right.

Furthermore, three circles of second annular grooves 501 are arranged on the hollow driving shaft 5 inside the auxiliary cylinder barrel 3, a mounting hole 301 along the radial direction of the second annular groove 501 in the middle is arranged on the auxiliary cylinder barrel 3, a support spring 302 and a support 303 are sequentially arranged in the mounting hole 301 from outside to inside, and one end, in contact with the annular grooves, of the support 303 is spherical.

In the above embodiment, three circles of the second annular grooves 501 are provided in the hollow drive shaft 5, the top post 303 having a spherical head is mounted on the sub-cylinder 3, and the top post spring 302 is provided at the rear of the top post 303. When the hollow driving shaft 5 passes through two adjacent second annular grooves 501, the large resistance needs to be overcome, and when the hollow driving shaft 5 enters the second annular grooves 501, the small force is needed, so that the hollow driving shaft 5 has corresponding vibration hand feeling in the moving process, and a driver can know whether the hollow driving shaft 5 is moved in place or not by the hand feeling.

Further, the center of the control core shaft 6 is provided with an exhaust blind hole 601 extending from the left end to the right top ring 9, and the side wall of the exhaust blind hole 601 is provided with an exhaust hole 602 communicated with the left chamber and the right chamber on the control core shaft 6.

In the above embodiment, the left end of the control core shaft 6 is provided with the blind exhaust hole 601 extending to the right top ring 9, the side wall of the blind exhaust hole 601 is provided with the exhaust hole 602 communicating the left chamber and the right chamber, and the end cover 2 of the main cylinder barrel 1 is provided with the air release hole 10, so that the left chamber and the right chamber can be kept communicating with the atmosphere and in a low pressure state. When the control mandrel 6 opens the gas passage between the hollow piston 401 and the left or right chamber, the hollow piston 401 is driven to move in the opposite direction by the instantaneous high pressure in the left or right chamber.

Further, the left top ring 8 and the right top ring 9 are fixed on the control core shaft 6 through spring collars. In the above embodiment, the left top ring 8 and the right top ring 9 are mounted on the control core shaft 6 through spring collars, sealing rings are arranged at the joints, and the sealing rings are sleeved on the left top ring 8 and the right top ring 9.

Further, the left sealing ring 406 is integrally formed with the hollow piston 401, and the right sealing ring 407 is fixedly connected to the inner wall of the hollow piston 401 through a spring collar.

In the above embodiment, the left sealing ring 703 may be integrally formed with the hollow piston 401 for convenience of assembly, and then, for assembly, the right sealing ring 705 needs to be detachably connected to the hollow piston 401.

Further, the right end of the hollow piston 401 is provided with an internal thread, the left end of the hollow driving shaft 5 is provided with an external thread matched with the internal thread, and the hollow piston 401 is in threaded connection with the hollow driving shaft 5.

Further, referring to fig. 2 and 3, a small seal ring 11 matched with the operation core shaft 6 is arranged inside the hollow driving shaft 5, a first oil seal 12 is arranged outside the small seal ring 11, and the first oil seal 12 is clamped and fixed inside the hollow driving shaft 5 through a spring collar 13; a large sealing ring 14 matched with the hollow driving shaft 5 is arranged in the auxiliary cylinder barrel 3, a second oil seal 15 is arranged outside the large sealing ring 14, and the second oil seal 15 is clamped and fixed in the auxiliary cylinder barrel 3 through a spring clamping ring 13.

Furthermore, the small sealing ring 11 and the large sealing ring 14 are made of polytetrafluoroethylene.

In the above embodiment, the small seal ring 11 made of polytetrafluoroethylene is mounted on the inner side of the first oil seal 12, so that the sealing performance between the control core shaft 6 and the hollow driving shaft 5 is improved; the sealing performance between the hollow driving shaft 5 and the auxiliary cylinder 3 is improved by installing the large seal ring 14 made of polytetrafluoroethylene on the inner side of the second oil seal 15. The product showed no oil leakage after 1617628 tests.

Furthermore, the end cover 2, the main cylinder barrel 1 and the auxiliary cylinder barrel 3 are connected into a whole through the four bolts.

Although the present invention has been described in detail in this specification with reference to specific embodiments and illustrative embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto based on the present invention. Accordingly, such modifications and improvements are intended to be within the scope of this invention as claimed.