CN218747840U

CN218747840U - A linear motion device for deep sea robot

Info

Publication number: CN218747840U
Application number: CN202223211563.4U
Authority: CN
Inventors: 李彬; 陈鑫; 唐实; 陶祎春; 欧阳赛赛
Original assignee: Shenyang Institute of Automation of CAS
Current assignee: Shenyang Institute of Automation of CAS
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2023-03-28
Anticipated expiration: 2032-12-01

Abstract

The utility model relates to a linear motion device for deep sea robot, wherein inside planetary gear subassembly and the drive gear subassembly of being equipped with of differential mechanism, planetary gear subassembly includes the ring gear, planetary gear and intermediate gear, and the planetary gear equipartition is between ring gear and intermediate gear, first motor and ring gear coaxial coupling, the second motor passes through second power input shaft and intermediate gear coaxial coupling, the driving gear suit of drive gear subassembly initiating terminal is on second power input shaft, the driving gear outer fringe is equipped with the connecting rod axle, arbitrary planetary gear suit is on the connecting rod axle, the terminal second bevel gear suit of drive gear subassembly is on the transmission shaft, the transmission shaft both ends all are equipped with the transmission case, linear drive subassembly is installed respectively on corresponding the transmission case, two linear drive subassemblies pass through transmission shaft drive synchronous telescope, and the transmission shaft passes through both sides transmission case transmission moment. The utility model discloses a two motor redundancy designs, and can bear the side direction load and the deep sea pressure that equipment produced at the underwater motion.

Description

A linear motion device for deep sea robot

Technical Field

The utility model belongs to the technical field of underwater robot and specifically relates to a linear motion device for deep sea robot.

Background

A remote controlled underwater Robot (ROV) is a device commonly used in deep sea exploration and salvage operations, and can be used as a carrier to assemble various underwater tools according to different work tasks to realize different functions, and in order to better cover application scenarios of different types of underwater robots, as shown in fig. 6, a variable structure underwater robot is a reliable research direction, that is, the structural characteristics of the underwater robot are changed through structural deformation, so that the underwater robot has the working capabilities of more than two types of conventional underwater devices. At present, linear deformation is a common mode in the field of variable-structure underwater robots, but a hydraulic driving mode is mostly adopted in a traditional large-load linear mechanism, such as a hydraulic cylinder, a scissor mechanism and the like, and the problems of large space requirement, complex configuration, insufficient stability, mechanism interference and the like of a hydraulic system in a deep sea environment are considered, so that the conventional large-load linear mechanism is not suitable for a deep sea robot. Moreover, deep sea working conditions have higher requirements on the working reliability of the motor, the conventional electric push rod is mostly in a single-motor configuration, once the motor fails, the task execution process is seriously influenced, so that the consideration of redundant configuration of the motor is very necessary, and because the equipment in the deep sea environment needs to bear great pressure, the internal oil filling is needed for realizing pressure compensation, however, the oil compensation capability provided by the conventional deep sea equipment is limited, and the design of a movement mechanism is limited.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a linear motion device for deep sea robot, it is the redundant design of bi-motor, still can normally work when arbitrary motor breaks down to can bear equipment at the produced side direction load of underwater motion and deep sea pressure.

The purpose of the utility model is realized through the following technical scheme:

the utility model provides a linear motion device for deep sea robot, includes first motor, second motor, differential mechanism, transmission shaft, transmission case and linear drive subassembly, wherein differential mechanism inside is equipped with planetary gear subassembly and drive gear subassembly, planetary gear subassembly includes ring gear, planetary gear and intermediate gear, and planetary gear along the circumferencial direction equipartition in between ring gear and the intermediate gear, first motor with ring gear coaxial coupling, the second motor through a second power input shaft with intermediate gear coaxial coupling, the driving gear suit of transmission gear subassembly initiating terminal is in on the second power input shaft, the driving gear outer fringe is equipped with the connecting rod axle, arbitrary planetary gear suit in on the connecting rod axle, the terminal second cone gear suit of transmission gear subassembly is in on the transmission shaft, the transmission shaft both ends all are equipped with the transmission case, and linear drive subassembly installs respectively on the transmission case of corresponding side, and two linear drive subassemblies pass through the synchronous flexible of transmission shaft drive, just the transmission shaft passes through the transmission case transmission moment transmission of both sides.

Differential mechanism includes the differential box, just differential box one side is equipped with first power input shaft, and the opposite side is equipped with second power input shaft, wherein first power input shaft one end with first motor coaxial coupling, the other end with ring gear coaxial coupling, second power input shaft one end with second motor coaxial coupling, the other end with intermediate gear coaxial coupling, be equipped with first stopper on the first power input shaft, be equipped with the second stopper on the second power input shaft.

The transmission gear assembly comprises a driving gear, a transmission gear, a driven gear, a first bevel gear and a second bevel gear, wherein the driving gear, the transmission gear and the driven gear are sequentially meshed, the driven gear is coaxially connected with the first bevel gear, and the first bevel gear is meshed with the second bevel gear.

The linear driving assembly comprises a driving screw rod, an inner piston rod, an inner cylinder barrel, an outer piston rod and an outer cylinder barrel, wherein the driving screw rod is arranged in the inner piston rod, a nut is arranged in the inner piston rod and sleeved on the driving screw rod, the inner piston rod is arranged in the inner cylinder barrel, the inner cylinder barrel is arranged in the outer piston rod, the upper end of the outer piston rod is fixedly connected with the upper end of the inner piston rod, the outer piston rod is arranged in the outer cylinder barrel, the lower ends of the inner cylinder barrel and the outer cylinder barrel are arranged on a box body of the transmission box, the lower end of the driving screw rod extends into the transmission box and is connected with a transmission assembly arranged in the transmission box, the driving screw rod is driven to rotate by the transmission shaft, and the transmission shaft transmits torque through the transmission assembly.

The upper end of the driving screw rod is provided with a piston block, moving seal rings are arranged between the piston block and an inner piston rod and between the inner piston rod and an inner cylinder barrel, a sealed accommodating cavity is arranged inside a box body of the transmission case and communicated with the inside of the inner cylinder barrel, the transmission assembly is arranged in the sealed accommodating cavity, and an oil filling opening is formed in one side of the box body and communicated with the sealed accommodating cavity.

The upper end of the inner piston rod is provided with a through hole, the upper end of the inner cylinder barrel is provided with an exhaust valve, and the upper end of the outer cylinder barrel is provided with an exhaust port.

And the transmission assembly in the transmission box comprises a worm and a worm wheel which are meshed with each other, wherein the worm is connected with the transmission shaft, and the worm wheel is coaxially connected with the driving screw rod.

The middle of the worm wheel is provided with a worm wheel through hole for the driving screw rod to pass through, a bearing and a locking nut are arranged in the sealed accommodating cavity and sleeved on the driving screw rod, the bearing is limited by the locking nut, and the lower end of the sealed accommodating cavity is provided with a sealing end cover.

The lower part of the inner piston rod is provided with an outer spigot surface, and the upper end of the inner cylinder barrel is provided with an inner spigot surface.

And a sliding bearing is arranged between the upper end of the outer cylinder barrel and the outer piston rod.

The utility model discloses an advantage does with positive effect:

1. the utility model discloses a two motor redundancy design, wherein when two motors all normally work, the utility model discloses a differential mechanism can couple the input of first motor and second motor, realizes the single output of power at last, avoids the load problem that two motor rigid connection produced, when an arbitrary motor breaks down, power take off still can be guaranteed to differential mechanism, and then guarantees that the device still can normally work.

2. The utility model discloses linear drive subassembly adopts the suit design of outer cylinder and inner cylinder, can bear the side direction load, and outer piston rod and inner piston rod are connected together, have both guaranteed that lift action and external load support, make the straight line mechanism diameter that needs the oil charge again can be as little as possible, in order to reduce fluid compensation demand, satisfy the pressure compensation requirement of deep sea pressure, wherein the utility model discloses well cavity design of inner piston rod makes the top of piston piece be the sea water, and the below is pressure compensation fluid, and when this design made the mechanism motion, seal chamber's volume change volume was depended on the linear motion distance of mechanism and the wall thickness area of inner piston rod, compares in the demand that common closed piston rod design can effectively reduce compensation fluid, and sea water when also conveniently retrieving simultaneously is discharged, avoids remaining the corruption of sea water to the part.

3. The utility model discloses linear drive subassembly adopts trapezoidal lead screw to worm and worm wheel in trapezoidal lead screw and the transmission case all possess good auto-lock characteristic, can cooperate the electric brake of losing to guarantee the utility model discloses auto-lock ability under unoperated state.

Drawings

Figure 1 is a schematic structural diagram of the present invention,

figure 2 is a schematic view of the differential of figure 1,

figure 3 is a schematic diagram of the power transmission principle of the present invention,

figure 4 is a schematic view of the linear drive assembly of figure 1,

figure 5 is a cross-sectional view of the linear drive assembly of figure 4,

fig. 6 is a schematic diagram of a variable structure underwater robot.

The differential mechanism includes a differential mechanism 1, a planetary gear assembly 101, a ring gear 1011, a planetary gear 1012, an intermediate gear 1013, a second brake 102, a second power input shaft 103, a first power input shaft 104, a first brake 105, a differential case 106, a driving gear 107, a connecting rod shaft 1071, a transmission gear 108, a driven gear 109, a first bevel gear 110, a second bevel gear 111, a first motor 2, a linear driving assembly 3, a driving screw 301, a driving screw shaft 302, a pin shaft 303, a sliding bearing 304, a piston block 305, a nut 306, an inner piston rod 3061, an outer spigot surface 3061, an inner cylinder 307, an inner spigot surface 3071, an outer piston rod 308, an outer cylinder 309, an exhaust valve 310, a dynamic seal ring 311, a transmission shaft 4, a second motor 5, a transmission case 6, a worm 601, a worm 602, a worm wheel 6021, a through hole 604, an oil filler, a case 603, a bearing 607, a locking nut 606, and a sealing end cap.

Detailed Description

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

As shown in fig. 1-6, the utility model discloses a first motor 2, second motor 5, differential mechanism 1, transmission shaft 4, transmission case 6 and linear drive assembly 3, wherein as shown in fig. 2-3, differential mechanism 1 is inside to be equipped with planetary gear assembly 101 and drive gear subassembly, planetary gear assembly 101 includes ring gear 1011, planetary gear 1012 and intermediate gear 1013, and planetary gear 1012 along the circumferencial direction equipartition in between ring gear 1011 and the intermediate gear 1013, first motor 2 with ring gear 1011 coaxial coupling, second motor 5 is connected with a second power input shaft 103, just second power input shaft 103 axle head with intermediate gear 1013 coaxial coupling, the driving gear 107 of transmission gear assembly initiating terminal with second power input shaft 103 coaxial coupling, just the driving gear 107 outer fringe is equipped with connecting rod 1071, arbitrary gear 1012 suit in on the axle shaft 1, the terminal second bevel gear 111 suit of transmission gear assembly is in on transmission shaft 4, transmission shaft 4 both ends all are equipped with transmission case 6, and linear drive assembly 3 installs respectively in the transmission case 6 that corresponds the side, through two synchronous drive shaft transmission case transmission of flexible drive assembly 1074 both sides. The utility model discloses utilize differential 1 couples the input of first motor 2 and second motor 5, wherein ring gear 1011, planetary gear 1012 and intermediate gear 1013 among the planetary gear assembly 101 have the characteristic that the rotational speed of any one part can be confirmed by the respective rotational speed of remaining two parts, as shown in fig. 3, the utility model discloses in, first motor 2 drives ring gear 1011 and rotates, and second motor 5 drives intermediate gear 1013 and rotates, and any one planetary gear 1012 through connecting rod axle 1071 with driving gear 107 is connected, like this when two motors all normally work, differential 1 alright with the input of coupling first motor 2 and second motor 5, realize the single output of second bevel gear 111 at last, avoid the load problem that two motor rigid connection produced, when first motor 2 breaks down, intermediate gear 1013 still can drive through second motor 5, planetary gear 1012 connected with driving gear 107 rotates between ring gear 1011 and intermediate gear 1013 simultaneously, drives driving gear 107 output power, when second motor 5 breaks down, first motor 2 drives planetary gear 1012 and rotates, and the planetary gear 107 that is connected realizes the configuration of driving gear 107, thereby the redundant power output device that the planetary gear 107 configuration was realized this moment.

As shown in fig. 2 to 3, the differential 1 includes a differential case 106, and one side of the differential case 106 is provided with a rotatable first power input shaft 104, and the other side is provided with a rotatable second power input shaft 103, wherein one end of the first power input shaft 104 is coaxially connected with the first motor 2, the other end is coaxially connected with the gear ring 1011, one end of the second power input shaft 103 is coaxially connected with the second motor 5, the other end is coaxially connected with the driving gear 107 and the intermediate gear 1013, the first power input shaft 103 and the second power input shaft 104 are respectively rotatably mounted on a front side wall and a rear side wall of the differential case 106 through bearing supports, and as shown in fig. 3, the transmission shaft 4 passes through the differential case 106, and bearings for supporting the transmission shaft 4 to rotate are provided on left and right side walls of the differential case 106.

As shown in fig. 2 to 3, a first brake 105 and a second brake 102 are disposed inside the differential 1, wherein the first brake 105 is sleeved on the first power input shaft 104, and the second brake 102 is sleeved on the second power input shaft 102. In this embodiment, the first brake 105 and the second brake 102 are power-off brakes, and when any one of the motors fails, the control system causes the power-off brake corresponding to the motor to be powered off and locked, where the power-off brake is a commercially available product.

As shown in fig. 2 to 3, in this embodiment, the transmission gear assembly includes a driving gear 107, a transmission gear 108, a driven gear 109, a first bevel gear 110 and a second bevel gear 111, wherein the driving gear 107, the transmission gear 108 and the driven gear 109 are sequentially engaged, the driven gear 109 is coaxially connected to the first bevel gear 110, and the first bevel gear 110 is engaged with the second bevel gear 111.

As shown in fig. 3 to 5, in this embodiment, the linear driving assembly 3 includes a driving screw 301, an inner piston rod 306, an inner cylinder 307, an outer piston rod 308, and an outer cylinder 309, wherein the driving screw 301 is inserted into the inner piston rod 306, a nut 305 is disposed inside the inner piston rod 306 and sleeved on the driving screw 301, the inner piston rod 306 is disposed in the inner cylinder 307 and is driven by the driving screw 301 to move up and down along the inner cylinder 307, the inner cylinder 307 is disposed in the outer piston rod 308, an upper end of the outer piston rod 308 is fixedly connected to an upper end of the inner piston rod 306 through a pin 302, the outer piston rod 308 is disposed in the outer cylinder 309 and is driven by the inner piston rod 306 to move up and down along the outer cylinder 309, lower ends of the inner cylinder 307 and the outer cylinder 309 are disposed on a box 604 of the transmission case 6, a lower end of the driving screw 301 extends into the transmission case 6 and is connected to the transmission assembly disposed inside the transmission case 6, the driving screw 301 is driven to rotate by the transmission shaft 4, and the transmission shaft 4 transmits torque through the transmission assembly. The utility model discloses the outside outer cylinder 309 is the great straight line jar structure that can bear side direction load of diameter, and the utility model discloses utilize round pin axle 302 to be connected to together outer piston rod 308 and inner piston rod 306, both guaranteed that lift action and external load support, make simultaneously that the straight line mechanism diameter (interior cylinder body 307) that needs the oil charge can be as little as possible to reduce fluid compensation demand. When the utility model discloses when being in the deep sea environment, the well cavity design of inner piston rod 306 makes the top of piston piece 304 be the sea water, and the below is pressure compensation fluid, and when this design made the mechanism motion, seal chamber's volume change volume depended on the linear motion distance of mechanism and the wall thickness area of inner piston rod 306, compares in the demand that common closed piston rod design can effectively reduce compensation fluid.

As shown in fig. 5, in this embodiment, a piston block 304 is disposed at an upper end of the driving screw 301, dynamic seal rings 311 are disposed between the piston block 304 and the inner piston rod 306 and between the inner piston rod 306 and the inner cylinder 307, a seal accommodating chamber is disposed inside a box body 604 of the transmission case 6 and is communicated with the inside of the inner cylinder 307, a seal ring 608 is also disposed between a lower end of the inner cylinder 307 and the box body 604, a through hole is disposed at an upper end of the inner piston rod 306, as shown in fig. 4, an oil filling port 603 is disposed at one side of the box body 604 and is communicated with the seal accommodating chamber, the oil filling port 603 is used for filling oil into the inner cylinder 307 to achieve pressure compensation, and each seal ring ensures sealing of the inner cylinder 307, and as shown in fig. 5, an exhaust valve 310 is disposed at an upper end of the inner cylinder 307, and an exhaust port is disposed at an upper end of the outer cylinder 309. During maintenance, compensation oil is injected into the inner cylinder 307 of the linear driving assembly 3 through the oil filling port 603, redundant gas is released through the exhaust valve 310 through the difference between the internal pressure and the external pressure, and when the mechanism is in a retraction state, an exhaust port on the outer cylinder 309 is aligned with the exhaust valve 310, so that manual operation is facilitated. Space between outer cylinder 309 and the interior cylinder 307 communicates with each other with the sea water, consequently need not consider pressure compensation's problem, works as the utility model discloses leave the seabed after, interior piston rod 306 leans on the through-hole discharge sea water of upper end, and wherein withdraws the back at the mechanism, interior piston rod 306 upper end inner wall just is located the last plane of piston block 304 for the sea water in the interior piston rod 306 can flow to outer cylinder 309 in through its upper end through-hole, and the drainage groove on rethread outer cylinder 309 flange and the box 604 discharges, thereby avoids remaining the corruption of sea water to the part.

As shown in fig. 5, in this embodiment, an outer stop surface 3061 is provided at a lower portion of the inner piston rod 306, an inner stop surface 3071 is provided at an upper end of the inner cylinder 307, and the outer stop surface 3061 and the inner stop surface 3071 cooperate to prevent the inner piston rod 306 from being disengaged and limit a rising height of the inner piston rod 306.

As shown in fig. 5, in this embodiment, a sliding bearing 303 is disposed between the upper end of the outer cylinder 309 and the outer piston rod 308 to ensure the sliding connection therebetween.

As shown in fig. 3 to 5, in this embodiment, the transmission assembly in the transmission case 6 includes a worm 601 and a worm wheel 602 that are engaged with each other, wherein the worm 601 is connected with the transmission shaft 4, the worm wheel 602 is coaxially connected with the driving lead screw 301, in addition, in this embodiment, the driving lead screw 301 adopts a trapezoidal lead screw, the worm 601 and the worm wheel 602 have good self-locking characteristics, and can cooperate with the power-off brake to ensure the self-locking capability of the present invention under the non-working state.

As shown in fig. 5, the worm 601 and the worm wheel 602 are both disposed in a sealed accommodating cavity inside the box 604, wherein a worm wheel through hole 6021 is disposed in the middle of the worm wheel 602 for the driving screw 301 to pass through, a bearing 605 and a locking nut 606 are disposed inside the sealed accommodating cavity and sleeved on the driving screw 301, the bearing 605 defines a position through the locking nut 606, and a sealing end cover 607 is disposed at the lower end of the sealed accommodating cavity to ensure sealing in the cavity.

The utility model discloses a theory of operation does:

the utility model discloses during operation, ring gear 1011 among the first motor 2 drive planetary gear assembly 101 rotates, intermediate gear 1013 among the second motor 5 drive planetary gear assembly rotates, and arbitrary one planetary gear 1012 through connecting rod axle 1071 with the driving gear 107 is connected, like this when two motors all normally work, differential 1 alright with the input of coupling first motor 2 and second motor 5, realize the single output of second bevel gear 111 finally and drive transmission shaft 4 and rotate, avoid the load problem that two motor rigid connection produced, when first motor 2 breaks down, intermediate gear 1013 then drives through second motor 5, planetary gear 1012 connected with driving gear 107 rotates between ring gear 1011 and intermediate gear 1013 simultaneously, drive driving gear 107 output power, when second motor 5 breaks down, first motor 2 passes through ring gear 1011 drive planetary gear 1012 and rotates, and the planetary gear 1012 who is connected with driving gear 107 drives this moment the rotatory output power that realizes of driving gear 107, thereby the normal work of holding device, realize the redundant configuration of motor. In addition, a first brake 105 and a second brake 102 are provided in the differential 1, and when any one of the motors fails, the control system causes the brake corresponding to the motor to be powered off and locked.

The utility model discloses a linear drive assembly 3 adopts the suit design of outer cylinder 309 and interior cylinder 307, and wherein the outer cylinder 309 in the outside is the great straight line jar structure that can bear the side direction load of diameter, and the utility model discloses utilize round pin axle 302 to be connected to together outer piston rod 308 and interior piston rod 306, both guarantee the lift action and support with the external load, make the straight line mechanism diameter (interior cylinder body 307) that needs the oil charge simultaneously can be as little as possible to reduce fluid compensation demand. When the utility model discloses when being in the deep sea environment, the cavity design of inner piston rod 306 makes the top of piston block 304 be the sea water, and the below is pressure compensation fluid, and this design is when making the mechanism motion, and seal chamber's volume change volume depends on the linear motion distance of mechanism and the wall thickness area of inner piston rod 306, compare in the demand that common closed piston rod design can effectively reduce compensation fluid, when maintaining, compensation fluid pours into linear drive assembly 3's inner cylinder 307 into through oil filler 603 on the transmission case 6 into to through inside and outside pressure differential with unnecessary gas through discharge valve 310 release, space between outer cylinder 309 and the inner cylinder 307 communicates with each other with the sea water, consequently need not consider pressure compensation's problem, works as the utility model discloses leave the seabed after, inner piston rod 306 leans on the through-hole to discharge the sea water, wherein after the mechanism is withdrawed, inner piston rod 306 upper end inner wall just is located the upper plane of piston block 304 for sea water in the inner piston rod 306 can flow to outer cylinder 309 in through its upper end through-hole, discharge through the outer flange 309 flange of rethread and the box 604 to avoid remaining the corruption of sea water drainage part.

The utility model discloses utilize drive screw 301 drive linear drive subassembly 3 to go up and down, guarantee to move reliably to drive screw 301 adopts trapezoidal lead screw, trapezoidal lead screw and worm 601 and worm wheel 602 possess good auto-lock characteristic, can cooperate the power-off brake to guarantee the utility model discloses auto-lock ability under non-operating condition.

As shown in fig. 6, an application example of the present invention is that the underwater robot includes an upper main body and a lower main body having different devices, and the upper main body and the lower main body are driven to open and close.

Claims

1. A linear motion device for a deep sea robot, characterized in that: including first motor (2), second motor (5), differential mechanism (1), transmission shaft (4), transmission case (6) and linear drive subassembly (3), wherein differential mechanism (1) inside is equipped with planetary gear subassembly (101) and transmission gear subassembly, planetary gear subassembly (101) include ring gear (1011), planetary gear (1012) and intermediate gear (1013), and planetary gear (1012) along the circumferencial direction equipartition in between ring gear (1011) and intermediate gear (1013), first motor (2) with ring gear (1011) coaxial coupling, second motor (5) through a second power input shaft (103) with intermediate gear (1013) coaxial coupling, driving gear (107) suit of transmission gear subassembly initiating terminal on second power input shaft (103), driving gear (107) outer fringe is equipped with connecting rod axle (1071), arbitrary planetary gear (1012) suit on connecting rod axle (1071), gear (111) suit in on transmission shaft (4) at second cone gear subassembly terminal, transmission shaft (4) both ends all are equipped with transmission case (6) and correspond on the transmission case (3) drive subassembly (3) synchronous drive subassembly, pass through two flexible drive subassembly (3) respectively, and the transmission shaft (4) transmits torque through the transmission boxes (6) on two sides.

2. The linear motion device for deep sea robot according to claim 1, characterized in that: differential mechanism (1) is including differential box (106), just differential box (106) one side is equipped with first power input shaft (104), and the opposite side is equipped with second power input shaft (103), wherein first power input shaft (104) one end with first motor (2) coaxial coupling, the other end with ring gear (1011) coaxial coupling, second power input shaft (103) one end with second motor (5) coaxial coupling, the other end with intermediate gear (1013) coaxial coupling, be equipped with first stopper (105) on first power input shaft (104), be equipped with second stopper (102) on second power input shaft (103).

3. The linear motion device for deep sea robot according to claim 1, characterized in that: the transmission gear assembly comprises a driving gear (107), a transmission gear (108), a driven gear (109), a first bevel gear (110) and a second bevel gear (111), wherein the driving gear (107), the transmission gear (108) and the driven gear (109) are sequentially meshed, the driven gear (109) is coaxially connected with the first bevel gear (110), and the first bevel gear (110) is meshed with the second bevel gear (111).

4. The linear motion device for deep sea robot according to claim 1, characterized in that: the linear driving assembly (3) comprises a driving screw rod (301), an inner piston rod (306), an inner cylinder barrel (307), an outer piston rod (308) and an outer cylinder barrel (309), wherein the driving screw rod (301) is arranged in the inner piston rod (306), a nut (305) is arranged inside the inner piston rod (306) and sleeved on the driving screw rod (301), the inner piston rod (306) is arranged in the inner cylinder barrel (307), the inner cylinder barrel (307) is arranged in the outer piston rod (308), the upper end of the outer piston rod (308) is fixedly connected with the upper end of the inner piston rod (306), the outer piston rod (308) is arranged in the outer cylinder barrel (309), the lower ends of the inner cylinder barrel (307) and the outer cylinder barrel (309) are arranged on a box body (604) of the transmission case (6), the lower end of the driving screw rod (301) extends into the transmission case (6) and is connected with the transmission assembly arranged inside the transmission case (6), the driving screw rod (301) is driven to rotate by the transmission shaft (4), and the transmission torque is transmitted by the transmission assembly (4).

5. The linear motion device for deep sea robots according to claim 4, characterized in that: the upper end of the driving screw rod (301) is provided with a piston block (304), movable sealing rings (311) are arranged between the piston block (304) and an inner piston rod (306) and between the inner piston rod (306) and an inner cylinder barrel (307), a sealed accommodating cavity is arranged inside a box body (604) of the transmission case (6), the sealed accommodating cavity is communicated with the inside of the inner cylinder barrel (307), the transmission assembly is arranged in the sealed accommodating cavity, and one side of the box body (604) is provided with an oil filling port (603) communicated with the sealed accommodating cavity.

6. The linear motion device for deep sea robot according to claim 5, characterized in that: the upper end of the inner piston rod (306) is provided with a through hole, the upper end of the inner cylinder barrel (307) is provided with an exhaust valve (310), and the upper end of the outer cylinder barrel (309) is provided with an exhaust port.

7. The linear motion device for deep sea robots according to claim 5, characterized in that: the transmission assembly in the transmission case (6) comprises a worm (601) and a worm wheel (602) which are meshed with each other, wherein the worm (601) is connected with the transmission shaft (4), and the worm wheel (602) is coaxially connected with the driving lead screw (301).

8. The linear motion device for deep sea robot according to claim 7, characterized in that: the middle of the worm wheel (602) is provided with a worm wheel through hole (6021) for the driving screw rod (301) to pass through, a bearing (605) and a locking nut (606) are arranged in the sealing accommodating cavity and sleeved on the driving screw rod (301), the bearing (605) is limited by the locking nut (606), and a sealing end cover (607) is arranged at the lower end of the sealing accommodating cavity.

9. The linear motion device for deep sea robot according to claim 4, characterized in that: the lower part of the inner piston rod (306) is provided with an outer spigot surface (3061), and the upper end of the inner cylinder barrel (307) is provided with an inner spigot surface (3071).

10. The linear motion device for deep sea robot according to claim 4, characterized in that: a sliding bearing (303) is arranged between the upper end of the outer cylinder barrel (309) and the outer piston rod (308).