CN209781335U - Piston type driving mechanism - Google Patents

Abstract

The utility model provides a piston actuating mechanism, including cylinder body, main piston assembly and vice piston assembly. The structure has main cavity and vice cavity in the cylinder body, and the main cavity is through the through-hole intercommunication with vice cavity, and for the one end of being connected with the through-hole, is equipped with the opening in the other end of main cavity. The main piston assembly comprises a main piston rod with one end inserted into the main cavity and a main piston fixedly connected to the insertion end of the main piston rod, and the other end of the main piston rod extends out of the cylinder body through an opening to form a driving end. The auxiliary piston assembly comprises an auxiliary piston rod and an auxiliary piston, wherein the auxiliary piston rod penetrates through the through hole, one end of the auxiliary piston rod is in transmission connection with the main piston assembly, and the auxiliary piston is fixedly connected to the auxiliary piston rod. The utility model discloses a piston actuating mechanism makes the drive end of main piston assembly can carry out the drive of straight stroke and angle stroke respectively, provides a novel technical scheme that the structure is compact relatively for compound piston actuating mechanism.

Description

Piston type driving mechanism

Technical Field

The utility model relates to a drive actuating mechanism technical field, in particular to piston actuating mechanism.

Background

With the increase of the degree of industrial automation, the piston type driving mechanism is more and more widely applied as an important driving form. In some operating scenarios, it is desirable to have a combined linear and angular stroke of the drive end of the piston. In the prior art, pistons meeting this requirement have mainly the following two forms:

(1) the rotation or swing of the angular travel depends on the spiral guide groove on the piston rod, and the guide key which can slide in the guide groove is fixedly arranged, and the rotation of the piston rod is realized through the guide groove by utilizing the linear motion of the piston rod relative to the guide key. This type of rotation or oscillation must be performed simultaneously with the linear stroke movement and the rotation trajectory is predetermined, so that the use is greatly limited.

(2) The main cylinder body realizes straight stroke movement by adopting a composite form of the main cylinder body and the auxiliary cylinder body, the auxiliary cylinder body drives the main cylinder body or the piston rod through a gear and a rack, the self straight line movement is changed into the rotary movement of the piston rod of the main cylinder body, and the rotation of the driving end or the swing of a certain angle is realized. The form has complex structure and large occupied space, is not beneficial to popularization and application, and the transmission of the gear and the rack easily causes the loss of mechanical efficiency.

SUMMERY OF THE UTILITY MODEL

in view of this, the present invention provides a piston driving mechanism to provide a novel piston driving actuator with a straight stroke and an angular stroke capable of acting respectively.

In order to achieve the above purpose, the technical scheme of the utility model is realized like this:

A piston drive mechanism comprising:

The cylinder body is internally provided with a main cavity and an auxiliary cavity, the main cavity and the auxiliary cavity are communicated through a through hole, and the other end of the main cavity is provided with an opening relative to one end connected with the through hole;

the main piston assembly comprises a main piston rod with one end inserted into the main cavity and a main piston fixedly connected to the insertion end of the main piston rod, and the other end of the main piston rod extends out of the cylinder body from the opening to form a driving end; the main cavity is provided with a left cavity and a right cavity which are positioned at two sides of the main piston due to the separation of the main piston, and the main piston rod can slide along the axis of the main piston rod due to the driving of the pressure difference of fluids in the left cavity and the right cavity;

the auxiliary piston assembly comprises an auxiliary piston rod and an auxiliary piston, wherein the auxiliary piston rod penetrates through the through hole, one end of the auxiliary piston rod is in transmission connection with the main piston assembly, and the auxiliary piston is fixedly connected to the auxiliary piston rod; the auxiliary piston is arranged in the auxiliary cavity, the auxiliary cavity is provided with a front cavity and a rear cavity which are positioned at two sides of the auxiliary piston due to the separation of the auxiliary piston, and the auxiliary piston is driven by the fluid pressure difference in the front cavity and the rear cavity, so that the main piston rod can be driven to swing by taking the axis of the main piston rod as the center.

furthermore, an insertion hole is formed at the insertion end of the main piston rod, and one end of the auxiliary piston rod is inserted into the insertion hole and is in transmission connection with the main piston rod.

furthermore, an upper groove is formed on the inner wall of the insertion hole, the upper groove is matched with the upper groove, a lower groove is formed on the outer peripheral wall of the auxiliary piston rod, and the auxiliary piston rod is in transmission connection with the main piston rod through a guide key embedded in the upper groove and the lower groove.

Furthermore, a threaded hole is formed in the main piston, and the insertion end of the main piston rod is inserted into the threaded hole and connected with the main piston in a threaded manner.

Further, the cylinder body is constructed in a detachably coupled multi-stage structure in an axial direction of the main piston rod.

Further, the cylinder body comprises a front cylinder body, a rear cylinder body and a rear end cover which are connected in sequence, the main cavity is constructed between the front cylinder body and the rear cylinder body, and the auxiliary cavity is constructed between the rear cylinder body and the rear end cover.

Furthermore, a mounting hole is formed in the middle of the rear end cover, and the other end of the auxiliary piston rod is inserted into the mounting hole relative to the end in transmission connection with the main piston rod.

Further, in the cover is equipped with the sealing washer on the main piston rod, the cylinder body is still located including the cover front end housing on the main piston rod, the front end housing with the connection can be dismantled to the preceding cylinder body, just the sealing washer clamp is arranged in preceding cylinder body with between the front end housing.

Furthermore, a left channel which can be communicated with the left cavity and the fluid and a right channel which can be communicated with the right cavity and the fluid are formed on the cylinder body.

Further, a front channel which can be communicated with the front cavity and the fluid and a rear channel which can be communicated with the rear cavity and the fluid are formed on the cylinder body.

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

(1) piston actuating mechanism, be provided with the cylinder body of the main cavity body and vice cavity, through the fluid drive master piston subassembly in the main cavity body, through the fluid drive slave piston subassembly of vice cavity to utilize the swing transmission of slave piston pole with slave piston subassembly to give master piston subassembly, make master piston subassembly's drive end can carry out the drive of straight stroke and angle stroke respectively, provide a novel technical scheme that the structure is compact relatively for compound piston actuating mechanism.

(2) The structure form that the auxiliary piston rod is inserted into the insertion hole of the main piston rod is adopted, the purpose of transmitting the swing of the auxiliary piston assembly to the main piston assembly is well achieved, the structure is compact and reasonable, and the arrangement of other functional structures is facilitated.

(3) The groove form matched with the key groove or the sliding groove is adopted, and the guide key is in transmission matching, so that the swinging transmission from the auxiliary piston assembly to the main piston assembly is realized, and the main piston assembly can still independently perform straight stroke movement and is not limited by the auxiliary piston assembly; the structure has reliable transmission performance and is convenient for technical realization.

(4) The main piston rod and the main piston are connected and mounted in a threaded connection mode, and processing and assembling are facilitated.

(5) the cylinder body is designed into a multi-section split structure, so that the structure is compact, the assembly and disassembly among all parts are convenient, and the technical implementation is convenient.

(6) The three parts of the front cylinder body, the rear cylinder body and the rear end cover are adopted to construct and form the main cavity body and the auxiliary cavity body, the design is simple and effective, and a reasonable arrangement scheme is provided.

(7) the mounting hole is formed in the middle of the rear end cover, so that the bearing of one end of the auxiliary piston rod is realized, and the auxiliary piston assembly is convenient to assemble in the auxiliary cavity.

(8) The front end cover is arranged at one end of the front cylinder body close to the driving end, and the front end cover and the front cylinder body clamp and sleeve the sealing ring on the main piston rod, so that the sliding seal of the cylindrical surface of the main piston rod at the opening of the front cylinder body is well formed, and the assembly and the technical implementation are facilitated.

(9) The left channel and the right channel which are communicated with fluid are arranged on the main cavity, so that the fluid which is driven by the straight stroke movement of the driving end can enter and exit, and the power fluid can be conveniently connected.

(10) the auxiliary cavity is provided with a front channel and a rear channel which are communicated with fluid, so that the fluid which drives the end angular stroke to move can enter and exit, the power fluid can be conveniently connected, and the technical implementation is convenient.

Drawings

The accompanying drawings, which form a part of the present disclosure, are provided to provide a further understanding of the present disclosure, and the exemplary embodiments and descriptions thereof are provided to explain the present disclosure, wherein the related terms in the front, back, up, down, and the like are only used to represent relative positional relationships, and do not constitute an undue limitation of the present disclosure. In the drawings:

Fig. 1 is a sectional view of a piston drive mechanism according to an embodiment of the present invention;

3 FIG. 3 2 3 is 3 a 3 sectional 3 view 3 taken 3 along 3 line 3 A 3- 3 A 3 of 3 FIG. 3 1 3; 3

FIG. 3 is a sectional view taken along line B-B of FIG. 1;

Fig. 4 is a schematic view of a piston driving mechanism according to an embodiment of the present invention in a state where a driving end is retracted by a straight stroke;

fig. 5 is a schematic view illustrating a state in which a drive end of a piston drive mechanism according to an embodiment of the present invention is extended in a straight stroke;

Fig. 6 is a schematic structural diagram illustrating a forward swing of a driving end of a piston driving mechanism to an extreme position according to an embodiment of the present invention;

FIG. 7 is a cross-sectional view C-C of FIG. 6;

Fig. 8 is a schematic structural diagram illustrating a structure in which the driving end of the piston driving mechanism swings in the reverse direction to the limit position according to the embodiment of the present invention;

FIG. 9 is a cross-sectional view D-D of FIG. 8;

Description of reference numerals:

1-cylinder body, 101-main cavity, 1011-left cavity, 1012-right cavity, 1013-left channel, 1014-right channel, 102-auxiliary cavity, 1021-front cavity, 1022-rear cavity, 1023-front channel, 1024-rear channel, 103-through hole, 104-opening, 105-front cylinder body, 106-rear cylinder body, 107-rear end cover, 1071-mounting hole, 108-front end cover, 109-assembly through hole, 110-positioning hole;

2-master piston assembly, 201-master piston rod, 2011-plug-in hole, 2012-upper groove, 202-master piston, 2021-threaded hole, 203-drive end;

3-auxiliary piston component, 301-auxiliary piston rod, 3011-lower groove, 302-auxiliary piston, 303-mounting bolt;

4-guide key and 5-sealing ring.

Detailed Description

It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The embodiment relates to a piston type driving mechanism which comprises a cylinder body, a main piston assembly and an auxiliary piston assembly. The structure has main cavity and vice cavity in the cylinder body, and the main cavity is through the through-hole intercommunication with vice cavity, and for the one end of being connected with the through-hole, is equipped with the opening in the other end of main cavity. The main piston assembly comprises a main piston rod with one end inserted into the main cavity and a main piston fixedly connected to the insertion end of the main piston rod, and the other end of the main piston rod extends out of the cylinder body through an opening to form a driving end. The auxiliary piston assembly comprises an auxiliary piston rod and an auxiliary piston, wherein the auxiliary piston rod penetrates through the through hole, one end of the auxiliary piston rod is in transmission connection with the main piston assembly, and the auxiliary piston is fixedly connected to the auxiliary piston rod; the secondary piston is disposed within the secondary cavity.

the piston type driving mechanism of the embodiment drives the main piston assembly through the fluid in the main cavity, drives the auxiliary piston assembly through the fluid in the auxiliary cavity, and utilizes the auxiliary piston rod to drive the auxiliary piston assembly to swing to the main piston assembly, so that the driving end of the main piston assembly can be driven by a straight stroke and an angular stroke respectively, and the novel piston type driving executing device capable of respectively acting by the straight stroke and the angular stroke is provided.

based on the above general inventive concept, an exemplary structure of the piston driving mechanism of the present embodiment is shown in fig. 1, and the piston driving mechanism includes a cylinder 1, a main piston assembly 2, and an auxiliary piston assembly 3.

Wherein the cylinder body 1 is constructed in a multi-sectional structure detachably coupled along an axial direction of the main piston rod 201; of course, it is also possible to adopt an integral construction for the middle part of the cylinder body 1, but to facilitate the assembly and disassembly of the various parts and to facilitate the technical implementation, and to make the structure of the cylinder body 1 relatively compact, preferably, adopting a multi-section type of splicing structure.

The cylinder block 1 includes a front cylinder block 105, a rear cylinder block 106, and a rear end cap 107 which are integrally installed in sequence, a main chamber 101 is constructed between the front cylinder block 105 and the rear cylinder block 106, and a sub-chamber 102 is constructed between the rear cylinder block 106 and the rear end cap 107. The design is simple and effective, and is a reasonable arrangement scheme.

In the piston drive mechanism of the present embodiment, the main chamber 101 and the sub chamber 102 communicate with each other via the through hole 103, and an opening 104 is provided at the other end of the main chamber 101 with respect to the end connected to the through hole 103. As shown in fig. 1, one end of the main piston rod 201 of the main piston assembly 2 is inserted into the main cavity 101 and is fixedly connected to the main piston 202; the other end of the main piston rod 201 extends out of the cylinder 1 from the opening 104 to constitute a driving end 203. The main cavity 101 is separated by the main piston 202 to form a left cavity 1011 and a right cavity 1012 at two sides of the main piston 202, and when the left cavity 1011 and the right cavity 1012 have a fluid pressure difference, the main piston 202 can be driven to slide along the axis of the main piston rod 201 to drive the main piston rod 201, so that the driving end 203 can move in a straight stroke.

an auxiliary piston 302 of the auxiliary piston component 3 is arranged in the auxiliary cavity 102, an auxiliary piston rod 301 of the auxiliary piston component 3 penetrates through the through hole 103, one end of the auxiliary piston rod is connected with the main piston component 2 in a transmission mode, and the other end of the auxiliary piston rod is fixedly connected to the auxiliary piston 302. As shown in fig. 3, the auxiliary piston 302 divides the auxiliary cavity 102 into a front cavity 1021 and a rear cavity 1022, and when there is a fluid pressure difference between the front cavity 1021 and the rear cavity 1022, the auxiliary piston 302 is driven to swing around the axis of the auxiliary piston rod 301, so as to drive the auxiliary piston rod 301 to swing and rotate, and further to transmit the angular stroke motion to the main piston assembly 2, thereby enabling the driving end 203 to move. Obviously, the secondary piston rod 301 and the primary piston rod 201 are arranged coaxially to achieve good wobble transmission and synchronous motion. Naturally, the transmission connection between the auxiliary piston rod 301 and the main piston assembly 2 may be realized by the connection between the auxiliary piston rod 301 and the main piston 202, or by the connection between the auxiliary piston rod 301 and the main piston rod 201, and the principle is followed to ensure that the driving end 203 is not limited by the auxiliary piston rod 301 when moving in a straight stroke, and the driving end 203 is driven by the auxiliary piston rod 301 when moving in an angular stroke to perform synchronization.

preferably, as shown in fig. 1, the secondary piston rod 301 of the present embodiment is drivingly connected to the primary piston rod 201. An insertion hole 2011 is formed at the insertion end of the main piston rod 201, and one end of the sub-piston rod 301 is inserted into the insertion hole 2011 and is drivingly connected to the main piston rod 201. By adopting the structure, the purpose of transmitting the swing of the auxiliary piston assembly 3 to the main piston assembly 2 is well realized, the structure is compact and reasonable, and the arrangement of other functional structures is convenient.

as shown in fig. 2, in order to ensure reliable transmission performance and facilitate technical implementation, the main piston rod 201 and the auxiliary piston rod 301 are in transmission connection in a groove form matched by a key slot or a sliding slot. An upper groove 2012 is formed in the inner wall of the insertion hole 2011 and matched with the upper groove 2012, a lower groove 3011 is formed in the outer peripheral wall of the auxiliary piston rod 301, and the auxiliary piston rod 301 and the main piston rod 201 are in transmission connection through a guide key 4 embedded in the upper groove 2012 and the lower groove 3011. Obviously, in order to reliably exert the driving performance of the guide key 4, one of the upper groove 2012 and the lower groove 3011 is designed to be a key groove to fit the guide key 4, and the other groove is designed to be a sliding groove to ensure that the main piston rod 201 can freely slide in a straight stroke relative to the sub-piston rod 301. The design realizes the swinging transmission from the auxiliary piston assembly 3 to the main piston assembly 2, and enables the main piston assembly 2 to independently perform the straight stroke motion without the limitation of the auxiliary piston assembly 3.

in this embodiment, the main piston rod 201 and the main piston 202 are connected and mounted by a screw connection method, which is convenient for processing and assembling. Specifically, a threaded hole 2021 is formed in the main piston 202, and the insertion end of the main piston rod 201 is inserted into the threaded hole 2021 and screwed to the main piston 202. In order to prevent the looseness between the two, it is preferable to add a locking nut or adopt a thread structure with a self-locking function.

In order to better support the non-transmission connected end of the auxiliary piston rod 301 and facilitate the assembly of the auxiliary piston assembly 3 in the auxiliary cavity 102, as shown in fig. 1, a mounting hole 1071 is formed in the middle of the rear end cap 107, and the other end of the auxiliary piston rod 301 is inserted into the mounting hole 1071 opposite to the end in transmission connection with the main piston rod 201.

As shown in fig. 1, the cylinder 1 further includes a front end cap 108 sleeved on the main piston rod 201, a sealing ring 5 is sleeved on the main piston rod 201, the front end cap 108 and the front cylinder body 105 are designed to be detachably connected and mounted, the sealing ring 5 is mounted on a sealing carrier bearing the main piston rod 201, the sealing carrier is clamped between the front cylinder body 105 and the front end cap 108, the sealing ring 5 is mounted in a sealing ring groove of the sealing carrier and sleeved on the main piston rod 201, so as to realize the sealing of the sealing carrier between the main piston rod 201. The seal rings 5 are provided between the main piston 202 and the inner wall of the main chamber 101, between the sub piston 302 and the inner wall of the sub chamber 102, and at the seal-bonded portions of the front cylinder 105, the rear cylinder 106, and the rear end cap 107, respectively, to seal and isolate the fluid. The design ensures the sliding seal of the cylindrical surface of the main piston rod 201 at the opening 104 of the front cylinder body 105, and is beneficial to assembly and technical implementation; and the sealing and the isolation of the fluid in each cavity are also ensured.

in order to realize the inlet and outlet of the fluid for driving the straight stroke movement of the driving end 203 and facilitate the connection of the power fluid, a left channel 1013 capable of communicating the left cavity 1011 and the fluid and a right channel 1014 capable of communicating the right cavity 1012 and the fluid are constructed on the cylinder body 1. Similarly, to facilitate the fluid to be driven into and out of the angular stroke motion of the driving end 203, to facilitate the connection of the power fluid, and to facilitate the implementation of the technology, the cylinder body 1 is configured with a front passage 1023 for communicating the front cavity 1021 and the fluid, and a rear passage 1024 for communicating the rear cavity 1022 and the fluid.

In the assembly of the piston drive mechanism of the present embodiment, first, the main piston rod 201 and the main piston 202 are assembled into a single body, then, one end of the assembly drive end 203 of the main piston rod 201 is inserted into the opening 104 of the front cylinder 105, and the main piston 202 is installed in the main cavity 101 with the seal ring 5 attached. Thereafter, the front cylinder 105 and the rear cylinder 106 are assembled. Then the auxiliary piston rod 301 and the auxiliary piston 302 are assembled, as shown in fig. 3, the two are fixedly connected through the mounting bolt 303, then one end of the auxiliary piston rod 301 in transmission connection is inserted into the through hole 103, the guide key 4 is assembled, then the auxiliary piston rod 301 is inserted into the main piston rod 201, and then the rear end cover 107 is installed. In the assembling process, the sealing ring 5 needs to be additionally arranged at each position of the sealing ring 5.

At the other end of the cylinder 1, the seal bearing member with the seal ring 5 mounted thereon is fitted over the main piston rod 201, and then the front end cap 108 is attached. At this time, the process of assembling the cylinder block 1 is completed by inserting a screw or a long bolt through the assembling through-hole 109 provided in each assembly as shown in fig. 3 and fastening a nut. Then, a driving end 203 is attached to one end of the main piston rod 201 located outside the cylinder 1.

Since the sub-chamber 102 is a sector-shaped chamber, correspondingly, the rear cylinder 106 and the rear end cap 107 should have a relatively fixed assembly angle when assembled, and in order to facilitate the positioning between the rear cylinder 106 and the rear end cap 107 when assembled, it is preferable that a positioning hole 110 and a corresponding positioning pin are provided at the joint surface of the two, as shown in fig. 3.

In the piston drive mechanism of the present embodiment, when driven, as shown in fig. 4, fluid flows in from the left channel 1013 and flows out from the right channel 1014, and the retracting operation of the straight stroke of the drive end 203 is realized.

as shown in fig. 5, when fluid flows in from the right channel 1014 and out from the left channel 1013, a straight stroke extension action of the driving end 203 is achieved.

As shown in fig. 6 and 7, when the fluid flows in from the front channel 1023 and flows out from the rear channel 1024, the driving end 203 performs the angular stroke rotation swing in the direction shown in fig. 7.

As shown in fig. 8 and 9, when fluid flows in from the rear channel 1024 and flows out from the front channel 1023, the driving end 203 is swung in the reverse direction, that is, in the direction shown in fig. 9.

The piston type driving mechanism described in this embodiment drives the main piston assembly 2 through the fluid in the main cavity 101, drives the auxiliary piston assembly 3 through the fluid in the auxiliary cavity 102, and drives the main piston assembly 2 through the swing of the auxiliary piston assembly 3 by using the auxiliary piston rod 301, so that the driving end 203 of the main piston assembly 2 can respectively drive a straight stroke and an angular stroke, and a novel technical scheme with a relatively compact structure is provided for the composite type piston type driving mechanism.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A piston drive mechanism, comprising:

The cylinder body (1) is internally provided with a main cavity (101) and a secondary cavity (102), the main cavity (101) and the secondary cavity (102) are communicated through a through hole (103), and relative to one end connected with the through hole (103), the other end of the main cavity (101) is provided with an opening (104);

The main piston assembly (2) comprises a main piston rod (201) with one end inserted into the main cavity (101) and a main piston (202) fixedly connected to the insertion end of the main piston rod (201), and the other end of the main piston rod (201) extends out of the cylinder body (1) from the opening (104) to form a driving end (203); the main cavity (101) is provided with a left cavity (1011) and a right cavity (1012) which are positioned at two sides of the main piston (202) due to the separation of the main piston (202), and the main piston rod (201) can slide along the axis thereof due to the driving of the difference of fluid pressures in the left cavity (1011) and the right cavity (1012);

The auxiliary piston assembly (3) comprises an auxiliary piston rod (301) which penetrates through the through hole (103) and is in transmission connection with the main piston assembly (2) at one end, and an auxiliary piston (302) which is fixedly connected to the auxiliary piston rod (301); the auxiliary piston (302) is arranged in the auxiliary cavity (102), the auxiliary cavity (102) is provided with a front cavity (1021) and a rear cavity (1022) which are positioned at two sides of the auxiliary piston (302) due to the separation of the auxiliary piston (302), and the auxiliary piston is driven by the pressure difference of fluid in the front cavity (1021) and the rear cavity (1022), so that the main piston rod (201) can be driven to swing by taking the axis of the main piston rod as the center.

2. The piston drive mechanism as defined in claim 1, wherein: an insertion hole (2011) is formed in the insertion end of the main piston rod (201), and one end of the auxiliary piston rod (301) is inserted into the insertion hole (2011) and is in transmission connection with the main piston rod (201).

3. The piston drive mechanism as defined in claim 2, wherein: an upper groove (2012) is formed on the inner wall of the insertion hole (2011), the upper groove (2012) is matched with the upper groove (2012), a lower groove (3011) is formed on the outer peripheral wall of the auxiliary piston rod (301), and the auxiliary piston rod (301) is in transmission connection with the main piston rod (201) through a guide key (4) embedded in the upper groove (2012) and the lower groove (3011).

4. The piston drive mechanism as defined in claim 1, wherein: a threaded hole (2021) is formed in the main piston (202), and the insertion end of the main piston rod (201) is inserted into the threaded hole (2021) and is connected with the main piston (202) in a threaded manner.

5. The piston drive mechanism as defined in claim 1, wherein: the cylinder body (1) is constructed in a multi-section structure detachably connected in an axial direction of the main piston rod (201).

6. The piston drive mechanism as defined in claim 5, wherein: the cylinder body (1) comprises a front cylinder body (105), a rear cylinder body (106) and a rear end cover (107) which are connected in sequence, the main cavity (101) is constructed between the front cylinder body (105) and the rear cylinder body (106), and the auxiliary cavity (102) is constructed between the rear cylinder body (106) and the rear end cover (107).

7. the piston drive mechanism as defined in claim 6, wherein: a mounting hole (1071) is formed in the middle of the rear end cover (107), and the other end of the auxiliary piston rod (301) is inserted into the mounting hole (1071) relative to the end in transmission connection with the main piston rod (201).

8. the piston drive mechanism as defined in claim 6, wherein: the cylinder body (1) is further provided with a front end cover (108) sleeved on the main piston rod (201), the front end cover (108) is detachably connected with the front cylinder body (105), and the sealing ring (5) is clamped between the front cylinder body (105) and the front end cover (108).

9. the piston drive as defined in any one of claims 1-8, wherein: a left channel (1013) which can be communicated with the left cavity (1011) and the fluid and a right channel (1014) which can be communicated with the right cavity (1012) and the fluid are formed on the cylinder body (1).

10. The piston drive mechanism as defined in claim 9, wherein: a front channel (1023) which can be communicated with the front cavity (1021) and the fluid and a rear channel (1024) which can be communicated with the rear cavity (1022) and the fluid are formed on the cylinder body (1).