CN220687723U - Self-adjusting corner clamping cylinder - Google Patents

Abstract

The application belongs to the technical field of pressure cylinders, and particularly relates to a self-adjusting corner clamping cylinder. The device comprises a cylinder body, a piston assembly, an upper clamping arm and a lower clamping arm; an assembly cavity, a first clamping oil way, a first loosening oil way and a cylinder base are arranged in the cylinder body; the piston assembly comprises a main piston shaft and a secondary piston shaft; the auxiliary piston shaft is provided with a piston cavity, a second clamping oil way and a second loosening oil way, and the main piston shaft can be accommodated in the piston cavity in an up-and-down moving way; the auxiliary piston shaft passes through the piston shaft accommodating hole and can be accommodated in the assembly cavity in an up-and-down moving manner; the upper clamping arm is fixedly connected to the top end of the main piston shaft and used for pressing the upper side of the workpiece from top to bottom; the lower clamping arm is fixedly connected to the top end of the auxiliary piston shaft and used for propping up the lower side of the workpiece from bottom to top. Compared with the prior art, the clamping stability under the load is greatly improved, and safety accidents and damage to workpieces are prevented.

Description

Self-adjusting corner clamping cylinder

Technical Field

The application belongs to the technical field of pressure cylinders, and particularly relates to a self-adjusting corner clamping cylinder.

Background

The corner cylinder is an indispensable clamping element for a numerical control machine tool, particularly a machining center, to improve working efficiency, and is also used for a fixture for welding, assembling and the like. The existing corner cylinder is usually provided with only one pressing arm, the pressing arm presses down and rotates to a designed specified position and angle, and then the workpiece is pressed down and clamped in a straight line to finish clamping the workpiece. Such clamping is usually achieved by the use of a workpiece support below the workpiece, with corner cylinders acting on the workpiece and the workpiece support. In this case, the workpiece support needs to simultaneously receive the combined thrust force generated by the corner cylinder and the processing tool, and therefore, a support tool of a sufficiently large size is required for support, which not only brings inconvenience to workpiece processing, but also causes a weak workpiece clamping effect and also easily causes hard damage to the workpiece.

Disclosure of Invention

In view of this, the present application provides a self-adjusting corner clamping cylinder to address the technical problems described in the background section.

The solution provided by the application for solving the technical problems is as follows:

a self-adjusting corner clamping cylinder comprises a cylinder body, a piston assembly, a locking sleeve, an upper clamping arm and a lower clamping arm; an assembly cavity, a first clamping oil way, a first loosening oil way and a cylinder base are arranged in the cylinder body; the cylinder base is fixed at the bottom of the cylinder body and is provided with a piston shaft accommodating hole; the piston assembly comprises a main piston shaft and a secondary piston shaft; the auxiliary piston shaft is provided with a piston cavity, a second clamping oil way and a second loosening oil way, the main piston shaft can be accommodated in the piston cavity in a vertical moving way, and the upper end part of the main piston shaft is exposed out of the top end of the piston cavity; the auxiliary piston shaft passes through the piston shaft accommodating hole and can be accommodated in the assembly cavity in an up-and-down moving way, and the upper end part of the auxiliary piston shaft is exposed out of the top end of the piston cavity; the upper clamping arm is fixedly connected to the top end of the main piston shaft and used for pressing the upper side of the workpiece from top to bottom; the lower clamping arm is fixedly connected to the top end of the auxiliary piston shaft and used for propping up the lower side of the workpiece from bottom to top; the first clamping oil way is communicated with the second clamping oil way and is matched with the second clamping oil way to form a complete clamping oil way; the first loosening oil way is communicated with the second loosening oil way and is matched with the second loosening oil way to form a complete loosening oil way; the clamping oil way and the loosening oil way are communicated with the piston cavity.

Preferably, the auxiliary piston shaft comprises an auxiliary shaft rod and an auxiliary piston body from top to bottom in sequence; the auxiliary piston body is matched with the piston shaft accommodating hole, the auxiliary piston body penetrates through the piston shaft accommodating hole to be fixedly embedded on the auxiliary shaft rod, the lower end of the piston cavity is closed, and the lower end part of the auxiliary piston body is exposed out of the bottom end of the piston cavity.

Preferably, the part of the auxiliary piston body exposed out of the bottom end of the piston cavity is also in threaded connection with a limit nut; the top surface of the limit nut forms the upper limit of the auxiliary piston body; the upper surface of the cylinder base forms the lower limit of the auxiliary piston body.

Preferably, the main piston shaft comprises a main shaft rod, a main piston body and a navigation shaft from top to bottom in sequence; the navigation shaft is provided with a navigation groove, and the navigation groove sequentially comprises an arc groove section and a straight groove section from bottom to top; the upper end of the auxiliary piston body is provided with a navigation hole; the side wall of the navigation hole is provided with a navigation piece, and a part of the navigation piece extends into the navigation hole.

Preferably, the interior of the piston cavity is a stepped enclosing space, and a main shaft cavity, a main piston cavity and an auxiliary piston cavity are respectively arranged from top to bottom in sequence; the radius of the main shaft cavity is larger than that of the main piston cavity, and the junction of the main shaft cavity and the main piston cavity forms the upper limit of the main piston body; the main piston chamber is communicated with the navigation hole, the radius of the main piston chamber is larger than that of the navigation hole, and the junction of the main piston chamber and the navigation hole forms the lower limit of the main piston body, namely the main piston body is limited to move up and down in the main piston chamber.

Preferably, when the main piston body is in the upper limit, the navigation shaft part extends into the navigation hole, and at the moment, the navigation piece is clamped at the initial position of the arc groove section of the navigation groove; when the main piston body is in the lower limit, the top of the navigation shaft is abutted to the bottom surface of the navigation hole, and at the moment, the navigation piece is clamped at the tail end of the straight line groove section of the navigation groove.

Preferably, when the main piston body is at the upper limit and the auxiliary piston body is at the lower limit, the upper clamping arm and the lower clamping arm form an included angle with a certain degree; when the navigation piece is positioned at the initial position of the straight line groove section of the navigation groove, the degrees of the included angle formed by the upper clamping arm and the lower clamping arm are equal, namely, the upper clamping arm and the lower clamping arm are aligned.

Preferably, the communication part of the clamping oil way and the piston cavity is positioned at the upper limit part of the main piston body; the communication part of the loosening oil way and the piston cavity is positioned on the side wall of the main piston cavity.

Preferably, at least one sealing ring is arranged between the cylinder body and the auxiliary piston shaft and positioned above and below the clamping oil path and the loosening oil path respectively; at least one sealing ring is arranged between the auxiliary shaft rod and the auxiliary piston body.

Preferably, the self-adjusting corner clamping cylinder further comprises a locking sleeve; a locking oil way is also arranged in the cylinder body; the locking sleeve is sleeved on the outer side surface of the auxiliary piston shaft, and a certain gap is formed between the assembly cavity and the locking sleeve to form a locking oil groove; the locking oil circuit is communicated with the locking oil groove and used for providing deformation pressure for the locking sleeve, and the locking sleeve can elastically deform under the action of the deformation pressure of the locking oil circuit so as to lock the piston assembly.

The working method of the self-adjusting corner clamping cylinder adopting any technical scheme comprises the following steps:

the method comprises the steps that firstly, a self-adjusting corner clamping cylinder is in an original loosening state, namely an upper clamping arm is in an upper limit position, and a lower clamping arm is in a lower limit position;

secondly, defining the height of the lower clamping arm as QM, the workpiece adjusting stroke as CA and the positioning height of the lower height of the workpiece as QP; placing a workpiece above the lower clamping arm, wherein the placing height of the workpiece meets the following formula: qp=qm+0.5×ca;

opening a clamping oil way, feeding hydraulic oil into the upper part of the main piston body from the clamping oil way, applying downward pressure to the main piston body, driving the upper clamping arm to rotate by a certain angle by the main piston shaft to align with the lower clamping arm, and then linearly moving downwards to the upper surface of a workpiece, wherein the workpiece is limited in such a way that the upper clamping arm cannot continuously linearly move downwards;

the hydraulic oil is continuously added into the clamping oil way, so that upward thrust can be applied to the auxiliary piston shaft, the auxiliary piston shaft drives the lower clamping arm to linearly move upwards to the lower surface of the workpiece, and the workpiece is clamped by the upper clamping arm and the lower clamping arm at the same time;

fourthly, closing the clamping oil way and opening the locking oil way when the system detects that the pressure applied to the workpiece by the upper clamping arm and the lower clamping arm reaches a preset value; feeding hydraulic oil into the locking oil groove from the locking oil way, applying pressure to the side wall of the locking sleeve, and closing the locking oil way until the pressure applied to the piston assembly by the locking sleeve reaches a preset value by the locking sleeve under the action of the pressure of the locking oil way and the pressure of the locking sleeve;

fifthly, when the workpiece needs to be loosened, simultaneously opening the clamping oil way and the locking oil way, and withdrawing hydraulic oil from the clamping oil way and the locking oil way; simultaneously opening a release oil way, and feeding hydraulic oil into the main piston chamber from the release oil way; the lower part of the main piston body can apply upward thrust, and simultaneously, downward pressure is applied to the auxiliary piston body, at the moment, the main piston shaft drives the upper clamping arm to linearly move upwards to leave the upper surface of the workpiece, and the auxiliary piston shaft drives the lower clamping arm to linearly move downwards to leave the lower surface of the workpiece until the upper clamping arm is at an upper limit position, and the lower clamping arm is at a lower limit position, so that the operation is stopped.

The beneficial technical effects are as follows:

1. according to the self-adjusting corner clamping cylinder, the upper clamping arm and the lower clamping arm are automatically adjusted through the hydraulic oil feeding clamping oil way, the workpiece is clamped up and down from the upper surface clamping point and the lower surface clamping point of the workpiece respectively, and the acting force of the clamping cylinder is not applied to the workpiece support any more at the moment, but is only applied to the processed workpiece; compared with the prior art, the workpiece support only compensates vibration and thrust generated by the processing tool, so that the clamping stability under load is greatly improved;

2. the application provides a tight jar of self-interacting corner clamp, through hydraulic oil give into locking oil circuit to locking telescopic lateral wall applys pressure, locking sleeve can take place elastic deformation under locking oil circuit shape pressure force in order to lock the piston assembly, can be when the oil pressure is too big, automatic locking piston assembly prevents to appear incident and damage work piece.

The technical scheme and technical effects of the present application will be described in detail below with reference to the drawings and the detailed description of the specification.

Drawings

FIG. 1 is a schematic view of the self-adjusting angle clamping cylinder of the present application in an original undamped condition;

FIG. 2 is a schematic cross-sectional view of the self-adjusting corner clamping cylinder of the present application in an original undamped condition;

FIG. 3 is a schematic structural view of the main piston shaft of the present application;

FIG. 4 is a schematic front view of the self-adjusting corner clamping cylinder of the present application in an original undamped condition;

FIG. 5 is a schematic view of the self-adjusting corner clamping cylinder of the present application in a clamped condition;

identification description:

10-cylinder body, 20-piston assembly, 30-locking sleeve, 40-upper clamping arm, 50-lower clamping arm, 60-limit nut, 70-sealing ring and 80-workpiece;

110-an assembly cavity, 120-a first clamping oil way, 130-a locking oil way, 140-a first loosening oil way, 150-a cylinder base, 160-a clamping oil way and 170-a loosening oil way;

210-, 220-secondary piston shaft, 230-piston chamber;

2110-main shaft rod, 2120-main piston body, 2130-navigation shaft, 2140-navigation groove;

21410-arc groove sections, 21420-straight groove sections;

2210-auxiliary shaft rod, 2220-auxiliary piston body, 2230-second clamping oil way, 2240-second loosening oil way, 2250-navigation hole, 2260-navigation piece;

2310-spindle chamber, 2320-master piston chamber, 2330-slave piston chamber.

Detailed Description

Referring to fig. 1-5, a self-adjusting corner clamp cylinder disclosed herein includes a cylinder body 10, a piston assembly 20, a locking sleeve 30, an upper clamp arm 40, and a lower clamp arm 50; an assembly cavity 110, a first clamping oil path 120, a locking oil path 130, a first loosening oil path 140 and a cylinder base 150 are arranged in the cylinder body 10; the cylinder base 150 is fixed at the bottom of the cylinder body 10, and a piston shaft accommodating hole 1510 is formed in the cylinder base 150;

the piston assembly 20 includes a primary piston shaft 210 and a secondary piston shaft 220; the sub-piston shaft 220 is provided with a piston chamber 230, a second clamp oil passage 2230 and a second unclamping oil passage 2240, the main piston shaft 210 being accommodated in the piston chamber 230 so as to be movable up and down, and an upper end portion thereof being exposed to the top end of the piston chamber 230; the sub-piston shaft 220 passes through the piston shaft accommodating hole 1510 and is accommodated in the assembly chamber 110 to be movable up and down, and an upper end portion thereof is exposed to the top end of the piston chamber 230; the upper clamping arm 40 is fixedly connected to the top end of the main piston shaft 210 for pressing the upper side of the workpiece from top to bottom; the lower clamping arm 50 is fixedly connected to the top end of the auxiliary piston shaft 220 and is used for propping against the lower side of the workpiece from bottom to top;

the locking sleeve 30 is sleeved on the outer side surface of the auxiliary piston shaft 220, and a certain gap exists between the assembly cavity 110 and the locking sleeve 30 to form a locking oil groove 310; the locking oil path 130 is communicated with the locking oil groove 310 and is used for providing deformation pressure for the locking sleeve 30, and the locking sleeve 30 can be elastically deformed under the action of the deformation pressure of the locking oil path 130 so as to lock the piston assembly 20;

the first clamping oil path 120 and the second clamping oil path 2230 are communicated and cooperate to form a complete clamping oil path 160; the first release oil passage 140 and the second release oil passage 2240 are communicated and cooperate to form a complete release oil passage 170; both the clamp oil passage 160 and the unclamp oil passage 170 communicate with the piston chamber 230.

The secondary piston shaft 220 includes a secondary shaft rod 2210 and a secondary piston body 2220 in order from top to bottom; the secondary piston body 2220 is fitted with the piston shaft accommodating hole 1510, and the secondary piston body 2220 is fixedly engaged on the secondary shaft 2210 through the piston shaft accommodating hole 1510, closing the lower end of the piston chamber 230, and the lower end portion of the secondary piston body 2220 is exposed to the bottom end of the piston chamber 230.

The part of the auxiliary piston body 2220 exposed out of the bottom end of the piston cavity 230 is also in threaded connection with a limit nut 60; the top surface of the limit nut 60 constitutes an upper limit of the secondary piston body 2220; the upper surface of the cylinder base 150 constitutes a lower limit of the secondary piston body 2220.

The main piston shaft 210 includes, in order from top to bottom, a main shaft 2110, a main piston body 2120, and a pilot shaft 2130; the navigation shaft 2130 is provided with a navigation groove 2140, and the navigation groove 2140 sequentially comprises a cambered groove section 21410 and a linear groove section 21420 from bottom to top;

the upper end of the auxiliary piston body 2220 is provided with a navigation hole 2250; a navigation member 2260 is provided on a sidewall of the navigation hole 2250, and the navigation member 2260 partially extends into the navigation hole 2250.

The piston cavity 230 is internally provided with a stepped enclosing space, and a main shaft chamber 2310, a main piston chamber 2320 and a secondary piston chamber 2330 are respectively arranged from top to bottom in sequence;

the radius of the main shaft chamber 2310 is greater than the radius of the main piston chamber 2320, and the junction of the two forms the upper limit of the main piston body 2120; the main piston chamber 2320 communicates with the pilot hole 2250, and the radius of the main piston chamber 2320 is larger than that of the pilot hole 2250, and the junction between the main piston chamber 2320 and the pilot hole forms a lower limit of the main piston body 2120, that is, the main piston body 2120 is limited to move up and down in the main piston chamber 2320.

When the main piston body 2120 is at the upper limit, the navigation shaft 2130 partially extends into the navigation hole 2250, and at this time, the navigation piece 2260 is clamped at the starting position of the arc groove section 21410 of the navigation groove 2140; when the main piston body 2120 is at the lower limit, the top of the navigation shaft 2130 abuts against the bottom surface of the navigation hole 2250, and the navigation piece 2260 is clamped at the end of the linear groove segment 21420 of the navigation groove 2140.

When the primary piston body 2120 is in the upper limit and the secondary piston body 2220 is in the lower limit, the upper clamping arm 40 and the lower clamping arm 50 form an included angle of a certain degree, and a common included angle is 90 degrees, and can be customized to 45 degrees or 180 degrees. When the navigational 2260 is in the home position of the linear channel section 21420 of the navigational channel 2140, the upper clamping arm 40 forms an angle with the lower clamping arm 50 of 0 degrees, i.e., the two are aligned.

The communication between the clamping oil path 160 and the piston cavity 230 is located at the upper limit of the main piston body 2120; the unclamping oil line 170 is located on a sidewall of the master piston chamber 2320 where it communicates with the piston chamber 230.

At least one sealing ring 70 is respectively arranged between the cylinder body 10 and the auxiliary piston shaft 220 and above and below the clamping oil path 160 and the loosening oil path 170; at least one sealing ring 70 is respectively arranged between the cylinder body 10 and the locking sleeve 30 and above and below the locking oil path 130; at least one seal ring 70 is provided between the secondary shaft 2210 and the secondary piston body 2220.

Description of principle:

1. clamping operation: the self-adjusting corner clamp cylinder is in an original unclamped state before use, i.e., the upper clamp arm 40 is in the upper limit position and the lower clamp arm 50 is in the lower limit position. Placing the workpiece 80 above the lower clamp arm 50, opening the clamp oil path 160 to feed hydraulic oil from the clamp oil path 160 to the upper portion of the main piston body 2120, applying downward pressure thereto, and the main piston shaft 210 drives the upper clamp arm 40 to rotate by a certain angle to align with the lower clamp arm 50, and then linearly moves down to the upper surface of the workpiece 80, wherein the workpiece 80 restricts the upper clamp arm 40 from continuing to linearly move down; the hydraulic oil is continuously added into the clamping oil way 160, so that upward thrust can be applied to the auxiliary piston shaft 220, the auxiliary piston shaft 220 drives the lower clamping arm 50 to linearly move upwards to the lower surface of the workpiece 80, and at the moment, the workpiece 80 is clamped by the upper clamping arm 40 and the lower clamping arm 50 at the same time;

2. locking operation: closing the clamp oil passage 160 and simultaneously opening the lock oil passage 130 when the system detects that the pressure applied to the workpiece 80 by the upper clamp arm 40 and the lower clamp arm 50 reaches a preset value; hydraulic oil is fed into the locking oil groove 310 from the locking oil path 130, pressure is applied to the side wall of the locking sleeve 30, the locking sleeve 30 can be elastically deformed under the action of the shape variable pressure of the locking oil path 130 so as to lock the piston assembly 20, and the locking oil path 130 is closed until the pressure applied to the piston assembly 20 by the locking sleeve 30 reaches a preset value;

3. loosening operation: when the workpiece 80 needs to be loosened, the clamping oil circuit 160 and the locking oil circuit 130 are simultaneously opened, and hydraulic oil is withdrawn from the clamping oil circuit 160 and the locking oil circuit 130; simultaneously opening the unclamping oil path 170 to feed hydraulic oil from the unclamping oil path 170 into the master piston chamber 2320; the lower portion of the main piston body 2120 applies upward pushing force, and simultaneously applies downward pressure to the auxiliary piston body 2220, at this time, the main piston shaft 210 drives the upper clamping arm 40 to linearly move upward away from the upper surface of the workpiece 80, and the auxiliary piston shaft 220 drives the lower clamping arm 50 to linearly move downward away from the lower surface of the workpiece 80 until the upper clamping arm 40 is at the upper limit position, the lower clamping arm 50 is at the lower limit position, and the operation is stopped.

Description of effects:

1. the upper clamping arm and the lower clamping arm are automatically adjusted through the hydraulic oil feeding clamping oil way, and the workpiece is clamped up and down from the clamping points of the upper surface and the lower surface of the workpiece respectively, so that the acting force of the clamping cylinder is not applied to the workpiece support any more, but is only applied to the processed workpiece; compared with the prior art, the workpiece support only compensates vibration and thrust generated by the processing tool, so that the clamping stability under load is greatly improved;

2. the hydraulic oil is fed into the locking oil way to apply pressure to the side wall of the locking sleeve, the locking sleeve can be elastically deformed under the action of the shape variable pressure of the locking oil way to lock the piston assembly, and the piston assembly can be automatically locked when the oil pressure is overlarge, so that safety accidents and damage to workpieces are prevented.

The application also discloses a working method using the self-adjusting corner clamping cylinder, which comprises the following steps:

the first step, the self-adjusting corner clamping cylinder is in an original loosening state, namely the upper clamping arm 40 is at an upper limit position, and the lower clamping arm 50 is at a lower limit position;

second, defining the height of the lower clamping arm 50 as QM, the adjustment stroke of the workpiece 80 as CA, and the positioning height of the lower workpiece as QP; placing the workpiece 80 above the lower clamp arm 50, the placement height of the workpiece 80 satisfies the following equation: qp=qm+0.5×ca;

third, the clamping oil path 160 is opened, hydraulic oil is fed from the clamping oil path 160 to the upper part of the main piston body 2120, downward pressure is applied to the hydraulic oil, the main piston shaft 210 drives the upper clamping arm 40 to rotate by a certain angle to align with the lower clamping arm 50, and then the hydraulic oil moves linearly downwards to the upper surface of the workpiece 80, and at the moment, the workpiece 80 limits the upper clamping arm 40 to move linearly downwards;

the hydraulic oil is continuously added into the clamping oil way 160, so that upward thrust can be applied to the auxiliary piston shaft 220, the auxiliary piston shaft 220 drives the lower clamping arm 50 to linearly move upwards to the lower surface of the workpiece 80, and at the moment, the workpiece 80 is clamped by the upper clamping arm 40 and the lower clamping arm 50 at the same time;

fourth, when the system detects that the pressure applied to the workpiece 80 by the upper clamp arm 40 and the lower clamp arm 50 reaches a preset value, closing the clamp oil passage 160 while opening the lock oil passage 130; hydraulic oil is fed into the locking oil groove 310 from the locking oil path 130, pressure is applied to the side wall of the locking sleeve 30, the locking sleeve 30 can be elastically deformed under the action of the shape variable pressure of the locking oil path 130 so as to lock the piston assembly 20, and the locking oil path 130 is closed until the pressure applied to the piston assembly 20 by the locking sleeve 30 reaches a preset value;

fifthly, when the workpiece 80 needs to be loosened, simultaneously opening the clamping oil passage 160 and the locking oil passage 130, and withdrawing hydraulic oil from the clamping oil passage 160 and the locking oil passage 130; simultaneously opening the unclamping oil path 170 to feed hydraulic oil from the unclamping oil path 170 into the master piston chamber 2320; the lower portion of the main piston body 2120 applies upward pushing force, and simultaneously applies downward pressure to the auxiliary piston body 2220, at this time, the main piston shaft 210 drives the upper clamping arm 40 to linearly move upward away from the upper surface of the workpiece 80, and the auxiliary piston shaft 220 drives the lower clamping arm 50 to linearly move downward away from the lower surface of the workpiece 80 until the upper clamping arm 40 is at the upper limit position, the lower clamping arm 50 is at the lower limit position, and the operation is stopped.

The above description is not intended to limit the present application in any way, and any equivalent embodiments that can be changed or modified to equivalent variations using the technical disclosure disclosed above may be applied to other fields, but any simple modification, equivalent variations and modification to the above embodiments according to the technical matter of the present application will still fall within the scope of the technical disclosure of the present application, unless the technical disclosure of the present application is not limited thereto.

Claims (9)

1. A self-adjusting corner clamping cylinder which is characterized in that:

comprises a cylinder body (10), a piston assembly (20), an upper clamping arm (40) and a lower clamping arm (50);

an assembly cavity (110), a first clamping oil way (120), a first loosening oil way (140) and a cylinder base (150) are arranged in the cylinder body (10); the cylinder base (150) is fixed at the bottom of the cylinder body (10), and a piston shaft accommodating hole (1510) is formed in the cylinder base (150);

the piston assembly (20) includes a primary piston shaft (210) and a secondary piston shaft (220); the auxiliary piston shaft (220) is provided with a piston cavity (230), a second clamping oil way (2230) and a second loosening oil way (2240), the main piston shaft (210) can be accommodated in the piston cavity (230) in an up-and-down moving way, and the upper end part of the main piston shaft is exposed out of the top end of the piston cavity (230); the auxiliary piston shaft (220) passes through the piston shaft accommodating hole (1510) and is accommodated in the assembly cavity (110) in a vertically movable manner, and the upper end part of the auxiliary piston shaft is exposed out of the top end of the piston cavity (230); the upper clamping arm (40) is fixedly connected to the top end of the main piston shaft (210) and is used for pressing the upper side of the workpiece from top to bottom; the lower clamping arm (50) is fixedly connected to the top end of the auxiliary piston shaft (220) and used for propping up the lower side of the workpiece from bottom to top;

the first clamping oil way (120) and the second clamping oil way (2230) are communicated and matched to form a complete clamping oil way (160); the first loosening oil way (140) is communicated with the second loosening oil way (2240) and is matched with the second loosening oil way to form a complete loosening oil way (170); the clamping oil passage (160) and the unclamping oil passage (170) are both communicated with the piston chamber (230).

2. The self-adjusting corner clamping cylinder of claim 1, wherein:

the auxiliary piston shaft (220) comprises an auxiliary shaft rod (2210) and an auxiliary piston body (2220) from top to bottom in sequence; the auxiliary piston body (2220) is matched with the piston shaft accommodating hole (1510), the auxiliary piston body (2220) penetrates through the piston shaft accommodating hole (1510) to be fixedly embedded on the auxiliary shaft (2210), the lower end of the piston cavity (230) is closed, and the lower end part of the auxiliary piston body (2220) is exposed out of the bottom end of the piston cavity (230).

3. The self-adjusting corner clamping cylinder of claim 2, wherein:

the part of the auxiliary piston body (2220) exposed out of the bottom end of the piston cavity (230) is also in threaded connection with a limit nut (60); the top surface of the limit nut (60) forms the upper limit of the auxiliary piston body (2220); the upper surface of the cylinder base (150) constitutes a lower limit of the secondary piston body (2220).

4. A self-adjusting corner clamping cylinder as claimed in claim 3, wherein:

the main piston shaft (210) comprises a main shaft lever (2110), a main piston body (2120) and a navigation shaft (2130) from top to bottom in sequence; a navigation groove (2140) is arranged on the navigation shaft (2130), and the navigation groove (2140) sequentially comprises an arc groove section (21410) and a straight groove section (21420) from bottom to top;

the upper end of the auxiliary piston body (2220) is provided with a navigation hole (2250); a navigation piece (2260) is arranged on the side wall of the navigation hole (2250), and the navigation piece (2260) partially extends into the navigation hole (2250).

5. The self-adjusting corner clamping cylinder as defined in claim 4, wherein:

the piston cavity (230) is internally provided with a stepped enclosing space, and a main shaft chamber (2310), a main piston chamber (2320) and a secondary piston chamber (2330) are respectively arranged from top to bottom in sequence;

the radius of the main shaft chamber (2310) is smaller than that of the main piston chamber (2320), and the junction of the main shaft chamber (2310) and the main piston chamber forms the upper limit of the main piston body (2120); the main piston chamber (2320) is communicated with the navigation hole (2250), the radius of the main piston chamber (2320) is larger than that of the navigation hole (2250), and the junction of the main piston chamber (2320) and the navigation hole forms the lower limit of the main piston body (2120), namely, the main piston body (2120) is limited to move up and down in the main piston chamber (2320).

6. The self-adjusting corner clamping cylinder as defined in claim 5, wherein:

when the main piston body (2120) is at the upper limit, the navigation shaft (2130) partially stretches into the navigation hole (2250), and at the moment, the navigation piece (2260) is clamped at the starting position of the arc groove section (21410) of the navigation groove (2140); when the main piston body (2120) is at the lower limit, the top of the navigation shaft (2130) abuts against the bottom surface of the navigation hole (2250), and at the moment, the navigation piece (2260) is clamped at the tail end of the linear groove section (21420) of the navigation groove (2140).

7. The self-adjusting corner clamping cylinder as defined in claim 6, wherein:

when the main piston body (2120) is at an upper limit and the auxiliary piston body (2220) is at a lower limit, the upper clamping arm (40) and the lower clamping arm (50) form an included angle with a certain degree; when the navigation element (2260) is in the initial position of the linear groove section (21420) of the navigation groove (2140), the upper clamping arm (40) and the lower clamping arm (50) form an included angle with a degree of 0, namely, the two are aligned.

8. The self-adjusting corner clamping cylinder as defined in claim 7, wherein:

the communication part of the clamping oil way (160) and the piston cavity (230) is positioned at the upper limit part of the main piston body (2120); the unclamping oil path (170) is positioned on the side wall of the main piston chamber (2320) at the communication position of the unclamping oil path and the piston chamber (230).

9. The self-adjusting corner clamping cylinder as defined in claim 8, wherein:

at least one sealing ring (70) is respectively arranged between the cylinder body (10) and the auxiliary piston shaft (220) and above and below the clamping oil path (160) and the loosening oil path (170); at least one sealing ring (70) is arranged between the auxiliary shaft (2210) and the auxiliary piston body (2220).