阅读说明：本技术 一种水下机器人用内油箱 (Inner oil tank for underwater robot ) 是由 谭智铎 王旭 罗业腾 王启家 郭玉平 于 2020-12-09 设计创作，主要内容包括：本发明属于水下机器人领域,具体地说是一种水下机器人用内油箱,内油箱活塞及滚动膜片均容置于内油箱箱体内,滚动膜片的上端与内油箱活塞密封连接,下端与内油箱箱体的底部密封连接,内油箱活塞与内油箱箱体顶部之间设有预紧弹簧,预紧弹簧的上下两端分别与内油箱箱体顶部、内油箱活塞抵接；电位计安装于内油箱箱体的顶部,电位计的测量端伸入内油箱箱体内,并与内油箱活塞相连,随内油箱活塞升降；内油箱箱体底部密封螺纹连接有作为液压油进出口的调向接头。本发明结构简单、寿命长、可靠性高,可以广泛适用于各种水下机器人液压系统中。(The invention belongs to the field of underwater robots, and particularly relates to an inner oil tank for an underwater robot.A piston and a rolling diaphragm of the inner oil tank are both accommodated in a box body of the inner oil tank, the upper end of the rolling diaphragm is hermetically connected with the piston of the inner oil tank, the lower end of the rolling diaphragm is hermetically connected with the bottom of the box body of the inner oil tank, a pre-tightening spring is arranged between the piston of the inner oil tank and the top of the box body of the inner oil tank, and the upper end and the lower end of the pre-tightening spring are respectively abutted against the top of the box; the potentiometer is arranged at the top of the inner oil tank body, and the measuring end of the potentiometer extends into the inner oil tank body, is connected with the inner oil tank piston and rises and falls along with the inner oil tank piston; the bottom of the inner oil tank body is connected with a direction-adjusting joint serving as a hydraulic oil inlet and a hydraulic oil outlet in a sealing threaded manner. The invention has simple structure, long service life and high reliability, and can be widely applied to various underwater robot hydraulic systems.)

1. An internal oil tank for an underwater robot is characterized in that: the oil tank comprises an inner oil tank body, a potentiometer (7), a pre-tightening spring (8), an inner oil tank piston (12), a rolling diaphragm (14) and a direction adjusting joint (16), wherein the inner oil tank piston (12) and the rolling diaphragm (14) are both contained in the inner oil tank body, the upper end of the rolling diaphragm (14) is hermetically connected with the inner oil tank piston (12), the lower end of the rolling diaphragm is hermetically connected with the bottom of the inner oil tank body, the pre-tightening spring (8) is arranged between the inner oil tank piston (12) and the top of the inner oil tank body, and the upper end and the lower end of the pre-tightening spring (8) are respectively abutted against the top of the inner oil tank body and the inner oil tank piston (12); the potentiometer (7) is arranged at the top of the inner oil tank body, and the measuring end of the potentiometer (7) extends into the inner oil tank body, is connected with the inner oil tank piston (12) and is lifted along with the inner oil tank piston (12); the bottom of the inner oil tank body is connected with a direction-adjusting joint (16) serving as a hydraulic oil inlet and outlet in a sealing threaded manner.

2. The internal fuel tank for underwater robots as claimed in claim 1, wherein: the top of the inner oil tank body is respectively provided with a vacuum pump (11) and a throttle valve (20), and the vacuum pump (11) is communicated with the space between the piston (12) of the inner oil tank and the top of the inner oil tank body through a hose (18).

3. The internal fuel tank for underwater robots as claimed in claim 1, wherein: a guide rod (9) and a guide piston (10) are arranged in the inner oil tank body, the guide rod (9) penetrates through the inner oil tank piston (12), and the upper end and the lower end of the guide rod (9) are respectively inserted into the top and the bottom of the inner oil tank body; the guide piston (10) is arranged on the guide rod (9) in a sealing and sealing way in a relatively movable way, and the guide piston (10) is fixedly connected with the inner oil tank piston (12).

4. An internal fuel tank for an underwater robot as claimed in claim 3, wherein: a through hole A is formed in the middle of the upper surface of the inner oil tank piston (12), and the edge of the through hole A extends upwards along the axial direction of the guide rod (9) to form a matching spigot (22); the axial section of the guide piston (10) is in a cross shape, a through hole B is axially formed in the firm edge of the cross shape, the guide rod (9) penetrates through the through hole B, a star-shaped ring sealed with the guide rod (9) is arranged on the inner wall of the through hole B, and the cross edge of the cross shape is fixedly connected with the matching spigot (22); the lower end of the pre-tightening spring (8) is sleeved on the matching seam allowance (22).

5. The internal fuel tank for underwater robots as claimed in claim 1, wherein: the upper end of the rolling diaphragm (14) is fixedly connected with the lower surface of the inner oil tank piston (12) in a sealing way through a diaphragm pressing piece (13).

6. The internal fuel tank for underwater robots as claimed in claim 5, wherein: the edges of the upper end and the lower end of the rolling diaphragm (14) are provided with O-shaped rings during vulcanization molding, the O-shaped rings on the edge of the upper end of the rolling diaphragm (14) are embedded into an axial sealing groove formed in the lower surface of the inner oil tank piston (12), and the O-shaped rings and the inner oil tank piston (12) are sealed under the action of the pressing force of the diaphragm pressing piece (13); an O-shaped ring at the edge of the lower end of the rolling diaphragm (14) is sleeved in a radial sealing groove formed in the bottom of the inner oil tank body and is compressed by the side wall of the inner oil tank body to realize sealing; and part of the rolling diaphragm (14) is always abutted against the side wall of the inner oil tank body in the lifting process of the inner oil tank piston (12).

7. The internal fuel tank for underwater robots as claimed in claim 5, wherein: the lower surface of the inner oil tank piston (12) is provided with a positioning pin (2), one end of the positioning pin (2) penetrates through the diaphragm pressing piece (13) and is in threaded connection with the lower surface of the inner oil tank piston (12), and the other end of the positioning pin (2) is inserted into a pin hole (23) formed in the bottom of the inner oil tank body when the inner oil tank piston (12) is tightly attached to the bottom of the inner oil tank body.

8. The internal fuel tank for underwater robots as claimed in claim 1, wherein: the measuring end of the potentiometer (7) is connected with the inner oil tank piston (12) through a potentiometer connecting piece (3), the potentiometer connecting piece (3) comprises a mounting plate (301), a joint bearing (302), a pull rod head (303), a hexagonal nut (304) and an inner hexagonal socket head screw (305), one end of the mounting plate (301) is fixedly connected to the inner oil tank piston (12), the other end of the mounting plate is provided with the joint bearing (302), the joint bearing (302) is positioned through the inner hexagonal socket head screw (305) arranged on the side face of the mounting plate (301), and the pull rod head (303) penetrates through the joint bearing (302) and is fixedly connected through the hexagonal nut (304) in a threaded manner; and the measuring end of the potentiometer (7) is arranged on the pull rod head (303).

9. The internal fuel tank for underwater robots as claimed in claim 1, wherein: the potentiometer (7) is installed at the top of the inner oil tank body through a potentiometer fixing piece (5) and a potentiometer pressing piece (6), the potentiometer fixing piece (5) comprises a potentiometer connecting fixing seat (501), a pressing ring (502) and a screw (503), the axial section of the potentiometer connecting fixing seat (501) is in a cross shape, a through hole C is formed in the vertical side of the cross shape, and the transverse side of the cross shape is placed on the top of the inner oil tank body; the compression ring (502) is pressed on the cross-shaped transverse edge and is fixedly connected with the top of the inner oil tank body through a screw (503); the potentiometer (7) penetrates through the through hole C, and the potentiometer pressing piece (6) in threaded connection with the upper end of the cross-shaped vertical edge is fixedly connected to the potentiometer (7).

10. The internal fuel tank for underwater robots as claimed in claim 1, wherein: the inner oil tank body comprises an inner oil tank shell (1) and an inner oil tank upper cover (4) and an inner oil tank bottom cover (15) which are fixedly connected to the upper end and the lower end of the inner oil tank shell (1) respectively, a chamfer is arranged between the inner oil tank upper cover (4) and the inner oil tank shell (1) for sealing, and the inner oil tank bottom cover (15) and the inner oil tank shell (1) are sealed through an O-shaped ring which is formed by vulcanizing the lower end edge of a rolling diaphragm (14).

Technical Field

The invention belongs to the field of underwater robots, and particularly relates to an internal oil tank for an underwater robot.

Background

The underwater robot is used as an underwater measurement and operation platform and is widely applied to the application fields of marine scientific research, marine engineering, marine resource exploration, rescue and salvage and the like. The hydraulic system is a key core system of the underwater robot and can realize multiple functions of hydraulic driving, pressure compensation, buoyancy adjustment and the like. An underwater hydraulic system generally needs an oil tank structure to realize an oil storage function, and oil is sucked and discharged from the oil tank according to needs and is used for measuring the change of the oil quantity of the hydraulic system. The main body of the underwater fuel tank is usually realized by a rubber bag. Because the rigidity of the rubber bag is small, the shape change is irregular in the oil suction and discharge process, and the oil quantity change of the hydraulic system cannot be accurately measured.

Disclosure of Invention

In order to solve the problems of the existing underwater oil tank adopting a rubber bag as a main body, the invention aims to provide an internal oil tank for an underwater robot. This interior oil tank for underwater robot simple structure, reliable operation, oil mass change detect the precision high, and possess from the oil priming function.

The purpose of the invention is realized by the following technical scheme:

the invention comprises an inner oil tank body, a potentiometer, a pre-tightening spring, an inner oil tank piston, a rolling diaphragm and a direction-adjusting joint, wherein the inner oil tank piston and the rolling diaphragm are both accommodated in the inner oil tank body; the potentiometer is arranged at the top of the inner oil tank body, and the measuring end of the potentiometer extends into the inner oil tank body, is connected with the inner oil tank piston and rises and falls along with the inner oil tank piston; the bottom of the inner oil tank body is connected with a direction-adjusting joint serving as a hydraulic oil inlet and a hydraulic oil outlet in a sealing threaded manner.

Wherein: and the vacuum pump and the throttle valve are respectively installed at the top of the inner oil tank body, and the vacuum pump is communicated with the space between the piston of the inner oil tank and the top of the inner oil tank body through a hose.

A guide rod and a guide piston are arranged in the inner oil tank body, the guide rod penetrates through the inner oil tank piston, and the upper end and the lower end of the guide rod are respectively inserted into the top and the bottom of the inner oil tank body; the guide piston is arranged on the guide rod in a sealing and sealing way in a relatively movable way, and the guide piston is fixedly connected with the inner oil tank piston.

A through hole A is formed in the middle of the upper surface of the inner oil tank piston, and the edge of the through hole A extends upwards along the axial direction of the guide rod to form a matching spigot; the axial section of the guide piston is in a cross shape, a through hole B is axially formed in the firm edge of the cross shape, the guide rod penetrates through the through hole B, a star-shaped ring sealed with the guide rod is arranged on the inner wall of the through hole B, and the transverse edge of the cross shape is fixedly connected with the matching spigot; the lower end of the pre-tightening spring is sleeved on the matching seam allowance.

The upper end of the rolling diaphragm is fixedly connected with the lower surface of the piston of the inner oil tank in a sealing way through the diaphragm pressing piece.

The edges of the upper end and the lower end of the rolling diaphragm are provided with O-shaped rings during vulcanization molding, the O-shaped rings on the edge of the upper end of the rolling diaphragm are embedded into axial sealing grooves formed in the lower surface of the inner oil tank piston, and the O-shaped rings are sealed with the inner oil tank piston under the action of pressing force of the diaphragm pressing piece; the O-shaped ring at the lower end edge of the rolling diaphragm is sleeved in a radial sealing groove formed at the bottom of the inner oil tank body and is compressed by the side wall of the inner oil tank body to realize sealing; and part of the rolling diaphragm is always abutted against the side wall of the inner oil tank body in the lifting process of the inner oil tank piston.

The lower surface of the inner oil tank piston is provided with a positioning pin, one end of the positioning pin penetrates through the diaphragm pressing piece and is in threaded connection with the lower surface of the inner oil tank piston, and the other end of the positioning pin is inserted into a pin hole formed in the bottom of the inner oil tank body when the inner oil tank piston is tightly attached to the bottom of the inner oil tank body.

The measuring end of the potentiometer is connected with the inner oil tank piston through a potentiometer connecting piece, the potentiometer connecting piece comprises a mounting plate, a joint bearing, a pull rod head, a hexagon nut and an inner hexagon socket head cap screw, one end of the mounting plate is fixedly connected to the inner oil tank piston, the other end of the mounting plate is provided with the joint bearing, the joint bearing is positioned through the inner hexagon socket head cap screw arranged on the side surface of the mounting plate, and the pull rod head penetrates through the joint bearing and is fixedly connected through the hexagon nut in a threaded connection mode; and the measuring end of the potentiometer is arranged on the pull rod head.

The potentiometer is arranged at the top of the inner oil tank body through a potentiometer fixing piece and a potentiometer pressing piece, the potentiometer fixing piece comprises a potentiometer connecting fixing seat, a pressing ring and a screw, the axial section of the potentiometer connecting fixing seat is in a cross shape, a through hole C is formed in the vertical side of the cross shape, and the transverse side of the cross shape is placed on the top of the inner oil tank body; the compression ring is pressed on the cross-shaped transverse edge and is fixedly connected with the top of the inner oil tank body through a screw; the potentiometer penetrates through the through hole C, and the potentiometer pressing piece in threaded connection with the upper end of the cross-shaped vertical edge is fixedly connected to the potentiometer.

The inner oil tank body comprises an inner oil tank shell, an inner oil tank upper cover and an inner oil tank bottom cover, wherein the inner oil tank upper cover and the inner oil tank bottom cover are fixedly connected to the upper end and the lower end of the inner oil tank shell respectively, a chamfer is arranged between the inner oil tank upper cover and the inner oil tank shell for sealing, and the inner oil tank bottom cover and the inner oil tank shell are sealed through an O-shaped ring formed by vulcanizing the lower end edge of a rolling diaphragm.

The invention has the advantages and positive effects that:

1. the oil tank structure for realizing oil storage and oil suction and discharge of the underwater hydraulic system can be widely applied to the underwater hydraulic system and can reliably realize the oil storage function of the hydraulic system.

2. The invention adopts a rolling diaphragm type structure, changes the dynamic seal of the traditional piston motion into static seal, effectively reduces the leakage problem of the large-diameter piston in the motion process, and simultaneously reduces the processing difficulty of the inner oil tank piston and the inner oil tank shell; meanwhile, the linear potentiometer is utilized to detect the position of the piston of the inner oil tank, the linearity of the oil mass change is good, and the oil mass change in the inner oil tank can be accurately detected.

3. The pre-tightening spring is arranged in the inner oil tank, so that hydraulic oil in the inner oil tank has certain initial pressure, the rolling diaphragm is always in a tensioning state, the oil quantity detection precision of the hydraulic system is improved, and the hydraulic system is facilitated to absorb oil from the inner oil tank.

4. The inner oil tank is provided with the vacuum pump and used for the buoyancy adjusting system of the underwater robot, and the inner oil tank can be vacuumized to realize the self-suction oil return function.

5. The inner oil tank has large oil storage capacity, and the maximum oil storage capacity can be flexibly adjusted by adjusting the diameter of the inner oil tank and the stroke of the piston.

Drawings

FIG. 1 is a front view of the structure of the present invention (inner tank volume is largest);

FIG. 2 is a front view of the structure of the present invention (inner tank volume is minimum);

FIG. 3 is a right side view of the structure of the present invention;

FIG. 4 is an enlarged view of a portion of the potentiometer connecting member of the present invention;

FIG. 5 is an enlarged view of a portion of the potentiometer mounting member and the potentiometer compression member of the present invention;

FIG. 6 is an enlarged view of a portion of the pilot piston of the present invention;

wherein: the oil tank comprises an inner oil tank shell 1, a positioning pin 2, a potentiometer connecting piece 3, a mounting plate 301, a joint bearing 302, a draw rod head 303, a hexagon nut 304, a hexagon socket head cap screw 305, an inner oil tank upper cover 4, a potentiometer fixing piece 5, a potentiometer connecting fixing seat 501, a compression ring 502, a screw 503, a potentiometer compression piece 6, a potentiometer, a pre-tightening spring 8, a guide rod 9, a guide piston 10, a vacuum pump 11, an inner oil tank piston 12, a diaphragm compression piece 13, a rolling diaphragm 14, an inner oil tank bottom cover 15, a direction adjusting joint 16, an oil filling port plug 17, a hose 18, a vacuum pump fixing piece 19, a throttle valve 20, a hose joint 21, a matching stop 22 and a pin hole 23.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example one

As shown in fig. 1 to 6, the oil tank comprises an inner oil tank body, a potentiometer 7, a pre-tightening spring 8, an inner oil tank piston 12, a rolling diaphragm 14 and a direction adjusting joint 16, wherein the inner oil tank piston 12 and the rolling diaphragm 14 are both accommodated in the inner oil tank body, the inner oil tank body of the embodiment comprises an inner oil tank shell 1, an inner oil tank upper cover 4 and an inner oil tank bottom cover 15, the inner oil tank upper cover 4 covers the upper end of the inner oil tank shell 1, the inner oil tank upper cover 4 is fixedly connected with the inner oil tank shell 1 through bolts, and chamfer sealing is arranged between the inner oil tank upper cover 4 and the inner oil tank shell 1 to ensure good air tightness of the upper part in the inner oil tank. The inner oil tank bottom cover 15 is used as a fixing support, and meanwhile, the inner oil tank bottom cover 15 can be used for fixing and connecting the inner oil tank with other mechanisms.

The rolling diaphragm 14 is convoluted, the upper end of the rolling diaphragm 14 is fixedly connected with the lower surface of the inner oil tank piston 12 by the diaphragm pressing piece 13 through a cross-shaped sunk screw, and the lower end of the rolling diaphragm is hermetically connected with the bottom of the inner oil tank body (namely the inner oil tank bottom cover 15). In this embodiment, the edges of the upper and lower ends of the rolling diaphragm 14 are provided with O-rings during vulcanization molding, and the O-rings at the edge of the upper end of the rolling diaphragm 14 are embedded into an axial sealing groove formed in the lower surface of the inner oil tank piston 12 and are sealed with the inner oil tank piston 12 under the pressing force of the diaphragm pressing member 13; the O-shaped ring at the lower end edge of the rolling diaphragm 14 is sleeved in a radial sealing groove formed in the inner oil tank bottom cover 15, is compressed by the side wall of the inner oil tank body (namely the inner oil tank shell 1), and is fixedly connected with the inner oil tank shell 1 and the inner oil tank bottom cover 15 through bolts to realize sealing. The rolling diaphragm 14 is in partial contact with the inner surface of the inner tank case 1 all the time during the lifting of the inner tank piston 12.

The inside guide rod 9 and the guide piston 10 that are equipped with of the interior oil tank box of this embodiment, this guide rod 9 is passed by interior oil tank piston 12 to the grafting of the upper end of guide rod 9 and interior oil tank upper cover 4, the lower extreme pegs graft with the central tang of interior oil tank bottom cover 15 upper surface. In the present embodiment, a through hole a is formed in the middle of the upper surface of the inner tank piston 12, and the edge of the through hole a extends upward along the axial direction of the guide rod 9 to form a fitting spigot 22. The axial section of the guide piston 10 of the embodiment is in a cross shape, the lower end of the solid edge of the cross shape is inserted into the matching spigot 22 and sealed by an O-shaped sealing ring; the cross-shaped vertical edge is provided with a through hole B along the axial direction, the guide rod 9 passes through the through hole B, the inner wall of the through hole B is provided with a star-shaped ring which realizes sealing with the guide rod 9, the guide piston 10 and the guide rod 9 can move relatively, and the cross-shaped transverse edge is fixed on the matching spigot 22 of the inner oil tank piston 12 through a cross-shaped sunk screw.

In this embodiment, a pre-tightening spring 8 is disposed between the inner oil tank piston 12 and the top of the inner oil tank body (i.e., the inner oil tank upper cover 4), the upper end of the pre-tightening spring 8 abuts against the upper surface of the inner oil tank upper cover 4, and the lower end of the pre-tightening spring is sleeved on the matching seam allowance 22 of the inner oil tank piston 12.

The lower surface of the inner oil tank piston 12 of the embodiment is provided with a positioning pin 2, one end of the positioning pin 2 penetrates through the diaphragm pressing piece 13 and is in threaded connection with the lower surface of the inner oil tank piston 12, and the other end of the positioning pin 2 is inserted into a pin hole 23 formed in the bottom of the inner oil tank when the inner oil tank piston 12 is tightly attached to the bottom of the inner oil tank.

The potentiometer 7 of the embodiment is installed on the inner oil tank upper cover 4 through the potentiometer fixing piece 5 and the potentiometer pressing piece 6, and the measuring end of the potentiometer 7 extends into the inner oil tank body, is connected with the inner oil tank piston 12 through the potentiometer connecting piece 3 and ascends and descends along with the inner oil tank piston 12. The potentiometer connecting piece 3 of the embodiment comprises a mounting plate 301, a joint bearing 302, a draw bar head 303, a hexagon nut 304 and an inner hexagon socket head cap screw 305, wherein one end of the mounting plate 301 is fixedly connected to the inner oil tank piston 12, the other end of the mounting plate 301 is provided with the joint bearing 302, and the joint bearing 302 is mounted on the inner hexagon socket head cap screw 305 on the side surface of the mounting plate 301 through threads for positioning; the joint bearing 302 is arranged to prevent the potentiometer 7 from being subjected to shear stress; the draw bar head 303 is penetrated by a joint bearing 302 and is fixedly connected with the joint bearing through a hexagon nut 304; the measuring end of the potentiometer 7 is mounted on the tie rod head 303. The potentiometer fixing piece 5 of the embodiment comprises a potentiometer connecting fixing seat 501, a compression ring 502 and a screw 503, wherein the axial section of the potentiometer connecting fixing seat 501 is in a cross shape, a through hole C is formed in the vertical edge of the cross shape, and the transverse edge of the cross shape is placed on the inner oil tank upper cover 4; the compression ring 502 is pressed on the cross-shaped transverse edge and is fixedly connected with the inner oil tank upper cover 4 through a screw 503; the potentiometer 7 is penetrated by a through hole C, a potentiometer pressing piece 6 is fixedly connected to the potentiometer 7, the potentiometer 7 and the potentiometer pressing piece 6 are sealed through a sealing ring, the potentiometer pressing piece 6 is in threaded connection with the upper end of a cross-shaped vertical edge, and the potentiometer pressing piece 6 of the embodiment is a potentiometer pressing cap. The potentiometer of this embodiment is a prior art linear potentiometer.

The direction adjusting joint 16 and the oil filling port screwed plug 17 are connected with the inner oil tank bottom cover 15 through threads, and good sealing performance is ensured through axial sealing rings. The direction-adjusting joint 16 is connected with each hydraulic element of the hydraulic system and is an inlet and an outlet of hydraulic oil.

The installation of this embodiment is as follows:

the rolling diaphragm 14 is convoluted, and the upper end of the rolling diaphragm 14 is fixedly connected to the inner tank piston 12 by the diaphragm pressing member 13.

The guide piston 10 is fixed on the inner oil tank piston 12, three star-shaped rings are arranged in the guide piston 10, and the diameters of the guide piston 10 and the inner oil tank piston 12 are sealed by an O-shaped sealing ring.

The inner tank piston 12 is brought into close proximity with the inner tank bottom cap 15, as shown in the piston position of figure 2, and the locating pin 2 is aligned with the pin hole 23 in the inner tank bottom cap 15, and the guide rod 9 is passed through the guide piston 10 and inserted into the central spigot in the inner tank bottom cap 15.

The radial sealing ring at the lower end of the rolling diaphragm 14 is sleeved in the radial sealing groove on the inner oil tank bottom cover 15, then the inner oil tank shell 1 is used for pressing the O-shaped ring, and the inner oil tank shell 1 is fixedly connected with the inner oil tank bottom cover 15 through bolts.

The potentiometer 7 is firstly fixedly arranged on the potentiometer pressing piece 6, the potentiometer 7 and the potentiometer pressing piece are sealed through a sealing ring, then the potentiometer 7 is fixedly arranged on the inner oil tank upper cover 4 through the potentiometer fixing piece 5, the potentiometer 7 is stretched to the longest state, the measuring end of the potentiometer 7 is fixed on the inner oil tank piston 12 through the potentiometer connecting piece 3, and therefore the pull rod of the potentiometer 7 can move up and down along with the piston.

The direction adjusting joint 16 and the oil filling port screwed plug 17 are connected with the inner oil tank bottom cover 15 through screw threads.

And (3) loading the pre-tightening spring 8 into the inner oil tank, sleeving the pre-tightening spring on a matching spigot of the piston 12 of the inner oil tank, then covering the upper cover 4 of the inner oil tank, and fixedly connecting the upper cover 4 of the inner oil tank and the shell 1 of the inner oil tank by using bolts.

The working principle of the embodiment is as follows:

when the inner oil tank is in the most full state (as shown in fig. 1), the hydraulic system sucks oil from the inner oil tank, along with the reduction of oil, under the action of atmospheric pressure and a pre-tightening spring 8, the inner oil tank piston 12 moves downwards, the rolling diaphragm 14 performs regular convolution rolling along the inner wall of the inner oil tank shell 1 and the outer wall of the inner oil tank piston 12, the sealing effect between the inner oil tank piston 12 and the inner oil tank shell 1 is achieved, the inner oil tank piston 12 cannot deflect in the moving process under the guiding effect of the guide rod 9 and the guide piston 10, the clamping stagnation of the inner oil tank piston 12 in the moving process is prevented, and meanwhile, the good linearity of the inner oil tank in the oil quantity measuring process is guaranteed. The measuring end of the potentiometer 7 is connected with the inner oil tank piston 12, the potentiometer 7 detects the displacement of the inner oil tank piston 12 in real time in the downward moving process of the inner oil tank piston 12, and the variation of the hydraulic oil in the inner oil tank can be accurately calculated by combining the section diameter of the rolling diaphragm 14.

Oil return of the oil tank in this embodiment: when the inner oil tank is in a minimum state (as shown in fig. 2), the hydraulic system utilizes a hydraulic pump to inject hydraulic oil into the inner oil tank through the direction-adjusting joint 16, the piston 12 of the inner oil tank moves upwards along with the increase of the hydraulic oil, and the potentiometer 7 is utilized to detect the position of the piston 12 of the inner oil tank in real time in the moving process. The working mode is mainly suitable for various execution hydraulic systems, such as underwater hydraulic mechanical arms and the like.

Example two

The difference between this embodiment and the first embodiment is: in the embodiment, the vacuum pump 11 and the throttle valve 20 are respectively installed on the inner oil tank upper cover 4, the vacuum pump 11 is fixed at the upper end of a vacuum pump fixing piece 19 through a screw, and the lower end of the vacuum pump fixing piece 19 is installed on the inner oil tank upper cover 4 through a screw; the hose joint 21 is fixed to the inner tank upper lid 4 by a nut, and the space between the hose joint 21 and the inner tank upper lid 4 is sealed by an axial O-ring. The hose connector 21 is connected with the vacuum pump 11 through a hose 18, and the vacuum pump 11 is communicated with the space between the inner oil tank piston 12 and the inner oil tank upper cover 4 through the hose 18. The throttle valve 20 is fixedly connected to the inner oil bag upper cover 4 through a nut, and an axial sealing ring is arranged between the throttle valve 20 and the inner oil bag upper cover 4, so that good sealing performance is ensured.

The working principle of the embodiment is as follows:

in this embodiment, the oil absorption from the inner oil tank is the same as that in the first embodiment, and the oil return of the inner oil tank is as follows: when the inner tank is at its minimum (as shown in fig. 2), the vacuum pump 11 is activated to expel the gas above the inner tank piston 12 through the hose 18. Since the air is exhausted by the vacuum pump 11 at a faster rate than the air is introduced through the throttle 20, after a set period of time, a vacuum will be created in the upper portion of the piston 12 of the inner tank, which draws the oil in the hydraulic system back into the inner tank under the action of the internal and external atmospheric pressures. The potentiometer 7 is also used for detecting the change of the oil quantity in real time, when the oil return is completed, a stop valve in the hydraulic system is closed to cut off the flow of the oil between the inner oil tank and the system, simultaneously, the vacuum pump 11 stops working, and air slowly flows into the upper part of the inner oil tank through the throttle valve 20 to recover the upper air pressure to the atmospheric pressure. This mode is primarily used for hydraulic buoyancy adjustment systems.