Pressure compensation device of underwater motor

Abstract

A pressure compensation device of an underwater motor comprises a cylinder body, a seawater spring and a middle spring. The cylinder is connected with the permeable cover, the permeable cover is sequentially connected with the seawater spring, the front piston, the middle spring, the rear piston and the motor winding oil cavity, the seawater spring is located in the seawater cavity, the middle spring is located in the middle oil cavity, and hydraulic oil is further arranged in the middle oil cavity. Then the front piston moves to compress the middle oil cavity until the pressure in the seawater cavity, the middle oil cavity and the motor winding oil cavity is balanced, namely the pressure difference is balanced; the front piston and the rear piston seal the middle oil cavity, so that hydraulic oil in the middle oil cavity cannot leak, the sealing performance is good, the hydraulic oil can be used for a long time, and the long-term operation effect is good. Therefore, the pressure difference can be balanced for a long time, and the sealing performance is good.

Description

Technical Field

[0001] The invention relates to a pressure compensating device, belonging to the technical field of deep-sea underwater motor pressure compensating devices, and in particular to a pressure compensating device for an underwater motor. Background Art

[0002] At present, electric motors are used as driving devices for ultra-deep submersibles. However, in the ultra-deep seawater environment, there is a large seawater pressure, so the motor needs to balance the pressure difference between the internal insulating oil and the external seawater to maintain the long-term operation of the motor.

[0003] The Chinese patent application number is 201110161966.X, and the application date is June 16, 2011. It discloses an oil-filled pressure-compensated deep-sea motor and a manufacturing method thereof. A pressure compensator with a piston is connected to the tail end of the permanent-magnet brushless DC motor, and the inner cavities of the permanent-magnet brushless DC motor and the pressure compensator are interconnected. At the same time, the deformation resistance of the end shell of the pressure compensator close to the piston end face is made smaller than the deformation resistance of the permanent-magnet brushless DC motor shell. Then, the inner cavities of the permanent-magnet brushless DC motor and the pressure compensator are filled with insulating hydraulic oil. Although this design utilizes the deformation of the end shell of the pressure compensator to make the piston squeeze into the motor, thereby keeping the pressure inside and outside the motor balanced, it still has the following defects: This design uses the deformation of the shell to squeeze the hydraulic oil to balance the pressure inside and outside the motor. After the shell has undergone multiple deformations, it will be damaged, resulting in hydraulic oil leakage. After the hydraulic oil leaks, it is impossible to balance the pressure inside and outside the motor. Therefore, this design cannot balance the pressure difference for a long time.

[0004] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the application, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and problems existing in the prior art that the pressure difference cannot be balanced for a long time, and to provide a pressure compensation device for an underwater motor that can balance the pressure difference for a long time.

[0006] To achieve the above objectives, the technical solution of the present invention is: A pressure compensation device for an underwater motor, the device comprising a cylinder, a seawater spring and an intermediate spring; One end of the cylinder is a water inlet, which is connected to a water-permeable cover. A plurality of water-permeable holes are evenly distributed on the water-permeable cover, and the water-permeable holes are through holes. One end of the water-permeable cover located in the cylinder is connected to one end of a seawater spring, and the seawater spring is located in the seawater cavity. The other end of the seawater spring is connected to one end of a front piston, and the outer surface of the front piston is connected to the inner surface of the cylinder. The other end of the front piston is connected to one end of an intermediate spring, and the intermediate spring is located in an intermediate oil cavity, in which hydraulic oil is distributed. The other end of the intermediate spring is connected to one end of a rear piston, and the outer surface of the rear piston is connected to the inner surface of the cylinder, and the other end of the rear piston is connected to one end of the motor winding oil cavity. The end of the cylinder away from the water inlet is a flange end, and the flange end is connected to one end of an underwater motor.

[0007] The seawater spring is in a compressed state, and the intermediate spring is in a compressed state.

[0008] A plurality of sealing grooves and a middle guide ring groove are distributed on the outer surface of the front piston, a sealing ring is arranged in the sealing groove, and a middle guide ring is arranged in the middle guide ring groove.

[0009] The sealing groove includes a first waterproof groove, a second waterproof groove, a first oil-proof groove and a front step ring groove which are distributed in sequence, a first waterproof U-shaped ring is inserted in the first waterproof groove, a second waterproof U-shaped ring is inserted in the second waterproof groove, a first oil-proof U-shaped ring is inserted in the first oil-proof groove, and a front step ring is inserted in the front step ring groove.

[0010] The middle guide ring groove includes a first middle guide ring groove and a second middle guide ring groove, the first middle guide ring groove is located between the first oil-proof groove and the front step ring groove, the first middle guide ring is inserted into the first middle guide ring groove, the second middle guide ring groove is located on the extension line of the front step ring groove away from the first oil-proof groove, and the second middle guide ring is inserted into the second middle guide ring groove.

[0011] A rear guide ring groove and a rear step ring groove are distributed on the outer surface of the rear piston, a rear guide ring is inserted in the rear guide ring groove, and a rear step ring is inserted in the rear step ring groove.

[0012] The rear guide ring groove includes a rear first guide ring groove and a rear second guide ring groove, a rear step ring groove is between the rear first guide ring groove and the rear second guide ring groove, a rear first guide ring is inserted in the rear first guide ring groove, and a rear second guide ring is inserted in the rear second guide ring groove.

[0013] The flange end comprises an end face sealing groove and two radial sealing grooves. An end face sealing ring is arranged in the end face sealing groove, and radial sealing rings are arranged in the radial sealing grooves.

[0014] A threaded hole is arranged in one end of the rear piston close to the motor winding oil chamber, and one end of the water leakage sensor is inserted into the threaded hole.

[0015] The outer surface of the end of the water-permeable cover away from the seawater spring is covered with a filter cover, and a plurality of filter holes are evenly distributed on the filter cover; and a scraper ring is arranged on the end of the front piston close to the seawater spring.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In a pressure compensation device for an underwater motor of the present invention, the device comprises a cylinder, a seawater spring and an intermediate spring, one end of the cylinder is connected to a water-permeable cover, a water-permeable hole is arranged on the water-permeable cover, the water-permeable cover is connected to the seawater spring, the seawater spring is located in the seawater cavity, the other end of the seawater spring is connected to the front piston, the other end of the front piston is connected to the intermediate spring, the intermediate spring is located in the intermediate oil cavity, the other end of the intermediate spring is connected to one end of the rear piston, the other end of the rear piston is connected to one end of the motor winding oil cavity, one end of the cylinder close to the motor winding oil cavity is a flange end, the flange end is connected to one end of the underwater motor, when used, when the device and the underwater motor are both located in a seawater environment, seawater enters the seawater cavity through the water-permeable cover, at this time, the pressure of the seawater acts on the front piston, so the seawater pushes the front piston toward the rear piston, thereby compressing the volume of the intermediate oil cavity and the motor winding oil cavity, increasing the pressure of the intermediate oil cavity and the motor winding oil cavity, until the pressure of the seawater cavity, the intermediate oil cavity and the motor winding oil cavity is balanced, that is, the pressure difference is balanced, the advantages of the present invention also include: First point: The pressure of seawater will not cause deformation to the shell of this device. The middle oil chamber is sealed by the front piston and the rear piston, so the hydraulic oil in the middle oil chamber will not leak. The motor winding oil chamber is sealed by the rear piston and the flange end, so the motor oil in the motor winding oil chamber will not leak. Therefore, this device can balance the pressure difference for a long time. Second point: when the device is under atmospheric pressure, the seawater spring and the intermediate spring are first compressed, so pre-pressure is set in the intermediate oil chamber and the motor winding oil chamber; when the device is located in a deep sea environment, the pressure in the intermediate oil chamber and the motor winding oil chamber is the sum of the pre-pressure and the seawater pressure, and the pressure in the seawater chamber is the seawater pressure, so the pressure in the seawater chamber is less than the pressure in the intermediate oil chamber and the motor winding oil chamber, and the pressure difference is used to ensure the sealing of the intermediate oil chamber and the motor winding oil chamber, so the sealing of the device is better; Third point: When the seawater pressure gradually increases, the seawater gradually pushes the front piston to move toward the rear piston to gradually increase the pressure in the cylinder. Therefore, the device can adaptively adjust the pressure in the cylinder according to the seawater conditions. Therefore, the device has good adaptability to different seawater pressures. Fourth point: When seawater leaks from the front piston, seawater enters the middle oil chamber, but due to the sealing effect of the rear piston, seawater will not enter the motor winding oil chamber, so the motor winding can still be used normally, that is, the underwater motor can still be used normally; Therefore, the present invention can balance the pressure difference for a long time and has good sealing performance.

[0017] 2. In a pressure compensation device for an underwater motor of the present invention, the front piston is covered with a first waterproof U-shaped ring, a second waterproof U-shaped ring, a first oil-proof U-shaped ring, a first middle guide ring, a front step ring, and a second middle guide ring in sequence. When used, the first waterproof U-shaped ring and the second waterproof U-shaped ring prevent seawater from entering the middle oil chamber, and the first oil-proof U-shaped ring prevents the hydraulic oil in the middle oil chamber from leaking into the seawater chamber. The front step ring is used to improve the sealing effect, that is, to prevent the leakage of seawater and hydraulic oil at the same time. The first middle guide ring and the second middle guide ring provide support and guidance for the movement of the front piston, so the front piston has better sealing performance, which can well transmit the seawater pressure. Therefore, the present invention has better transmission performance for seawater pressure.

[0018] 3. In a pressure compensation device for an underwater motor of the present invention, the rear piston is covered with a rear first guide ring, a rear step ring and a rear second guide ring in sequence; an end face sealing ring and a radial sealing ring are arranged on the flange end. When used, the rear step ring is used to seal the intermediate oil chamber and the motor winding oil chamber to prevent leakage between the intermediate oil chamber and the motor winding oil chamber. The rear first guide ring and the rear second guide ring are used to provide support and guidance for the rear piston to stabilize the movement effect of the rear piston; the multiple seals on the flange end ensure the reliability of the seal between the device and the underwater motor. Therefore, the present invention operates stably.

[0019] 4. In a pressure compensation device for an underwater motor of the present invention, a water leakage sensor is provided on one end of the rear piston. When in use, after the seal of the front piston fails, the water leakage sensor sends out an alarm signal. If the water leakage sensor in the motor winding oil cavity does not send out an alarm signal and the motor winding insulation paper is not less than 100 milliohms, the motor winding oil cavity is not mixed with seawater, and the underwater motor can still operate normally; after the maintenance conditions are met, the front piston is repaired and replaced to restore its sealing performance. Therefore, the present invention has a self-detection function.

[0020] 5. In the pressure compensation device of an underwater motor of the present invention, a filter cover is provided on the water permeable cover, and a scraper ring is provided on the front piston. When used, the filter cover is used to filter larger debris, marine organisms, etc. in the seawater to prevent them from entering the seawater cavity and causing the seawater spring to be stuck. The scraper ring is used to remove marine organisms and dirt attached to the inner wall of the seawater cavity when the front piston moves back and forth, so it has a self-cleaning function. Therefore, the present invention has a self-cleaning function. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 yes Figure 1 sectional view of .

[0023] Figure 3 It is a schematic diagram of the present invention in the atmospheric state.

[0024] Figure 4 It is a schematic diagram of the present invention in a deep sea environment.

[0025] Figure 5 yes Figure 1 Schematic diagram of the structure of the mid-front piston.

[0026] Figure 6 yes Figure 5 Schematic diagram of the structure of the middle front step circle.

[0027] Figure 7 yes Figure 1 Schematic diagram of the structure of the middle and rear piston.

[0028] Figure 8 yes Figure 7 Schematic diagram of the structure of the middle and rear step circle.

[0029] Fig. 9 yes Figure 1 Schematic diagram of the structure of the middle flange end.

[0030] Fig.10 yes Figure 1 Schematic diagram of the structure of the middle permeable cover.

[0031] Fig.11 yes Fig.10 Schematic diagram of the structure of the water permeable hole.

[0032] In the figure: cylinder 1, water inlet 11, flange end 12, end face sealing groove 121, radial sealing groove 122, end face sealing ring 123, radial sealing ring 124, seawater spring 2, seawater cavity 21, intermediate spring 3, intermediate oil cavity 31, hydraulic oil 32, water permeable cover 4, water permeable hole 41, filter cover 42, filter hole 421, front piston 5, sealing groove 51, first waterproof groove 511, second waterproof groove 512, first oil-proof groove 513, front step ring groove 514, middle guide ring groove 52, first guide ring groove 521, middle second guide ring groove 522, sealing ring 5 3. First waterproof U-shaped ring 531, second waterproof U-shaped ring 532, first oil-proof U-shaped ring 533, front step ring 534, middle guide ring 54, middle first guide ring 541, middle second guide ring 542, scraper ring 55, dustproof groove 56, dustproof ring 561, rear piston 6, rear guide ring groove 61, rear first guide ring groove 611, rear second guide ring groove 612, rear step ring groove 62, rear step ring 621, rear guide ring 63, rear first guide ring 631, rear second guide ring 632, threaded hole 64, water leakage sensor 641, motor winding oil chamber 7. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] See also Figure 1 — Fig.11 , a pressure compensation device for an underwater motor, the device comprising a cylinder 1, a seawater spring 2 and an intermediate spring 3; One end of the cylinder 1 is a water inlet 11, which is connected to a water-permeable cover 4. A plurality of water-permeable holes 41 are evenly distributed on the water-permeable cover 4, and the water-permeable holes 41 are through holes. One end of the water-permeable cover 4 located in the cylinder 1 is connected to one end of a seawater spring 2, and the seawater spring 2 is located in a seawater cavity 21. The other end of the seawater spring 2 is connected to one end of a front piston 5, and the outer surface of the front piston 5 is connected to the inner surface of the cylinder 1. The other end of the front piston 5 is connected to one end of an intermediate spring 3, and the intermediate spring 3 is located in an intermediate oil cavity 31. Hydraulic oil 32 is distributed in the intermediate oil cavity 31. The other end of the intermediate spring 3 is connected to one end of a rear piston 6, and the outer surface of the rear piston 6 is connected to the inner surface of the cylinder 1. The other end of the rear piston 6 is connected to one end of a motor winding oil cavity 7; the end of the cylinder 1 away from the water inlet 11 is a flange end 12, and the flange end 12 is connected to one end of an underwater motor.

[0035] The seawater spring 2 is in a compressed state, and the intermediate spring 3 is in a compressed state.

[0036] A plurality of sealing grooves 51 and a middle guide ring groove 52 are distributed on the outer surface of the front piston 5 . A sealing ring 53 is arranged in the sealing groove 51 , and a middle guide ring 54 is arranged in the middle guide ring groove 52 .

[0037] The sealing groove 51 includes a first waterproof groove 511, a second waterproof groove 512, a first oil-proof groove 513 and a front step ring groove 514 which are distributed in sequence. The first waterproof groove 511 is inserted with a first waterproof U-shaped ring 531, the second waterproof groove 512 is inserted with a second waterproof U-shaped ring 532, the first oil-proof groove 513 is inserted with a first oil-proof U-shaped ring 533, and the front step ring groove 514 is inserted with a front step ring 534.

[0038] The middle guide ring groove 52 includes a middle first guide ring groove 521 and a middle second guide ring groove 522. The middle first guide ring groove 521 is located between the first oil-proof groove 513 and the front step ring groove 514. The middle first guide ring 541 is inserted into the middle first guide ring groove 521. The middle second guide ring groove 522 is located on the extension line of the front step ring groove 514 away from the first oil-proof groove 513. The middle second guide ring 542 is inserted into the middle second guide ring groove 522.

[0039] A rear guide ring groove 61 and a rear step ring groove 62 are distributed on the outer surface of the rear piston 6 . A rear guide ring 63 is inserted into the rear guide ring groove 61 , and a rear step ring 621 is inserted into the rear step ring groove 62 .

[0040] The rear guide ring groove 61 includes a rear first guide ring groove 611 and a rear second guide ring groove 612 , a rear step ring groove 62 is formed between the rear first guide ring groove 611 and the rear second guide ring groove 612 , a rear first guide ring 631 is inserted into the rear first guide ring groove 611 , and a rear second guide ring 632 is inserted into the rear second guide ring groove 612 .

[0041] The flange end 12 includes an end face sealing groove 121 and two radial sealing grooves 122 . An end face sealing ring 123 is disposed in the end face sealing groove 121 , and radial sealing rings 124 are disposed in the radial sealing grooves 122 .

[0042] A threaded hole 64 is provided in one end of the rear piston 6 close to the motor winding oil chamber 7 , and one end of a water leakage sensor 641 is inserted into the threaded hole 64 .

[0043] The outer surface of the end of the water-permeable cover 4 away from the seawater spring 2 is covered with a filter cover 42 , and a plurality of filter holes 421 are evenly distributed on the filter cover 42 ; the end of the front piston 5 close to the seawater spring 2 is provided with a scraper ring 55 .

[0044] The supplementary description of the present invention is as follows: The ultra-large diving depth mentioned in the present invention refers to: a very deep ocean depth below the sea level, generally exceeding 600 meters.

[0045] Embodiment 1: See also Figure 1 — Fig.11 A pressure compensation device for an underwater motor, the device comprising a cylinder 1, a seawater spring 2 and an intermediate spring 3; one end of the cylinder 1 is a water inlet 11, the water inlet 11 is connected to a water permeable cover 4, a plurality of water permeable holes 41 are evenly distributed on the water permeable cover 4, the water permeable holes 41 are through holes, one end of the water permeable cover 4 located in the cylinder 1 is connected to one end of the seawater spring 2, the seawater spring 2 is located in a seawater cavity 21, the other end of the seawater spring 2 is connected to one end of a front piston 5, the outer surface of the front piston 5 The front piston 5 is connected to the inner surface of the cylinder 1, and the other end of the front piston 5 is connected to one end of the intermediate spring 3. The intermediate spring 3 is located in the intermediate oil chamber 31. The intermediate oil chamber 31 is filled with hydraulic oil 32. The other end of the intermediate spring 3 is connected to one end of the rear piston 6. The outer surface of the rear piston 6 is connected to the inner surface of the cylinder 1, and the other end of the rear piston 6 is connected to one end of the motor winding oil chamber 7. The end of the cylinder 1 away from the water inlet 11 is a flange end 12, and the flange end 12 is connected to one end of the underwater motor. The seawater spring 2 is in a compressed state, and the intermediate spring 3 is in a compressed state. Preferably, the flange end is connected to the underwater motor by bolts.

[0046] During application, when the device is under atmospheric pressure, the seawater spring 2 and the intermediate spring 3 are first compressed to have a certain pre-compression force to ensure that the pressure in the seawater chamber 21 is slightly smaller than the pressure in the intermediate oil chamber 31 and the motor winding oil chamber 7, and the pressure difference is used to ensure the sealing of the intermediate oil chamber 31 and the motor winding oil chamber 7; then the device is placed in a seawater environment, at this time, seawater enters the seawater chamber from the water permeable hole 41, and then the pressure of the seawater acts on the end of the front piston 5 close to the seawater spring 2, so the seawater pushes the front piston 5 toward the rear piston 6, and the front piston 5 compresses the intermediate spring 3 and the hydraulic oil 32 in the intermediate oil chamber 31, so the pressure in the intermediate oil chamber 31 gradually increases until the pressures in the seawater chamber 21, the intermediate oil chamber 31 and the motor winding oil chamber 7 are balanced; when the device is located at the maximum working water depth, the rear piston 6 still has a certain residual stroke in the cylinder 1 to reserve a compensation margin, thereby improving the safety and reliability of the device.

[0047] Embodiment 2: The basic content is the same as that of Example 1, except that: See also Figure 1 — Figure 6A plurality of sealing grooves 51 and middle guide ring grooves 52 are distributed on the outer surface of the front piston 5. A sealing ring 53 is arranged in the sealing groove 51, and a middle guide ring 54 is arranged in the middle guide ring groove 52. The sealing groove 51 includes a first waterproof groove 511, a second waterproof groove 512, a first oil-proof groove 513 and a front step ring groove 514, which are distributed in sequence. A first waterproof U-shaped ring 531 is inserted in the first waterproof groove 511, a second waterproof U-shaped ring 532 is inserted in the second waterproof groove 512, a first oil-proof U-shaped ring 533 is inserted in the first oil-proof groove 513, and a front step ring 534 is inserted in the front step ring groove 514. The middle guide ring groove 52 includes a middle first guide ring groove 521 and a middle second guide ring groove 522. The middle first guide ring groove 521 is located between the first oil-proof groove 513 and the front step ring groove 514. The middle first guide ring 541 is inserted into the middle first guide ring groove 521. The middle second guide ring groove 522 is located on the extension line of the front step ring groove 514 away from the first oil-proof groove 513. The middle second guide ring 542 is inserted into the middle second guide ring groove 522. Preferably, a dustproof groove 56 is further provided at the front side of the first waterproof groove, and a dustproof ring 561 is provided in the dustproof groove 56.

[0048] When in use, the first waterproof U-shaped ring 531 and the second waterproof U-shaped ring 532 are used to prevent seawater from entering the middle oil chamber 31, the first oil-proof U-shaped ring 533 is used to prevent the hydraulic oil 32 in the middle oil chamber 31 from leaking, the first middle guide ring 541 and the second middle guide ring 542 are used to provide support and guidance for the front piston 5 to ensure stable movement of the front piston 5, and the front step ring 534 can prevent the leakage of seawater and hydraulic oil 32 at the same time, thereby further improving the sealing effect; the dustproof ring 561 is used to prevent dust from entering the front piston 5 to ensure smooth movement of the front piston 5.

[0049] Embodiment 3: The basic content is the same as that of Example 1, except that: See also Figure 1 — Figure 8 The outer surface of the rear piston 6 is provided with a rear guide ring groove 61 and a rear step ring groove 62. A rear guide ring 63 is inserted into the rear guide ring groove 61, and a rear step ring 621 is inserted into the rear step ring groove 62. The rear guide ring groove 61 includes a rear first guide ring groove 611 and a rear second guide ring groove 612. The rear step ring groove 62 is located between the rear first guide ring groove 611 and the rear second guide ring groove 612. A rear first guide ring 631 is inserted into the rear first guide ring groove 611, and a rear second guide ring 632 is inserted into the rear second guide ring groove 612. The flange end 12 includes an end face sealing groove 121 and two radial sealing grooves 122. An end face sealing ring 123 is provided in the end face sealing groove 121, and radial sealing rings 124 are provided in the radial sealing grooves 122.

[0050] When in use, the first rear guide ring 631 and the second rear guide ring 632 provide support and guidance for the movement of the rear piston 6, so that the movement effect of the rear piston 6 is stable. The rear step ring 621 is used to improve the sealing performance to prevent the hydraulic oil 32 in the middle oil chamber 31 and the motor oil in the motor winding oil chamber 7 from leaking from each other. The flange end 12 is provided with an end face sealing ring 123 and two radial sealing rings 124 to ensure that the connection between the flange end 12 and the underwater motor is stable and has good sealing performance.

[0051] Embodiment 4: The basic content is the same as that of Example 1, except that: See also Figure 1 — Figure 8 A threaded hole 64 is provided in one end of the rear piston 6 close to the motor winding oil chamber 7, and one end of a water leakage sensor 641 is inserted into the threaded hole 64.

[0052] During application, when the seal of the front piston 5 fails, seawater is mixed into the middle oil chamber 31, and the water leakage sensor 641 sends out an alarm signal. At this time, if the water leakage sensor in the motor winding oil chamber 7 does not trigger the alarm signal and the motor winding insulation value is not less than one hundred milliohms, seawater has not penetrated into the motor winding oil chamber 7, and the motor winding insulation value can still ensure the normal operation of the underwater motor. When the maintenance conditions are met, the front piston 5 can be repaired and replaced to restore its sealing performance.

[0053] Embodiment 5: The basic content is the same as that of Example 1, except that: See also Figure 1 — Fig.11 The outer surface of the end of the water permeable cover 4 away from the seawater spring 2 is covered with a filter cover 42, and a plurality of filter holes 421 are evenly distributed on the filter cover 42; a scraper ring 55 is provided on the end of the front piston 5 close to the seawater spring 2. Preferably, the water permeable cover 4 is fixed to the cylinder 1 by bolts, and the filter cover 42 is fixed to the water permeable cover 4 by bolts.

[0054] When in use, seawater enters the seawater cavity 21 through the filter holes 421. At this time, the filter holes 421 prevent larger debris, marine organisms, etc. in the seawater from entering the seawater cavity 21, thereby avoiding the seawater spring 2 from getting stuck. When the front piston 5 moves along the coastal water cavity 21, the scraper ring 55 moves along the coastal water cavity 21 to remove marine organisms and dirt attached to the inner wall of the seawater cavity 21.

[0055] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed by the present invention should be included in the protection scope recorded in the claims.

Claims

1. A pressure compensation device for an underwater motor, characterized in that: The device comprises a cylinder (1), a seawater spring (2) and an intermediate spring (3); One end of the cylinder (1) is a water inlet (11), and the water inlet (11) is connected to a water permeable cover (4). The water permeable cover (4) is evenly distributed with a plurality of water permeable holes (41), and the water permeable holes (41) are through holes. One end of the water permeable cover (4) located inside the cylinder (1) is connected to one end of a seawater spring (2), and the seawater spring (2) is located in the seawater cavity (21). The other end of the seawater spring (2) is connected to one end of a front piston (5), and the outer surface of the front piston (5) is connected to the inner surface of the cylinder (1). The front piston (5) ) is connected to one end of an intermediate spring (3), the intermediate spring (3) is located in an intermediate oil chamber (31), hydraulic oil (32) is distributed in the intermediate oil chamber (31), the other end of the intermediate spring (3) is connected to one end of a rear piston (6), the outer surface of the rear piston (6) is connected to the inner surface of the cylinder (1), and the other end of the rear piston (6) is connected to one end of the motor winding oil chamber (7); the end of the cylinder (1) away from the water inlet (11) is a flange end (12), and the flange end (12) is connected to one end of the underwater motor.

2. A pressure compensation device for an underwater motor according to claim 1, characterized in that: The seawater spring (2) is in a compressed state, and the intermediate spring (3) is in a compressed state.

3. A pressure compensation device for an underwater motor according to claim 1 or 2, characterized in that: A plurality of sealing grooves (51) and a middle guide ring groove (52) are distributed on the outer surface of the front piston (5), a sealing ring (53) is arranged in the sealing groove (51), and a middle guide ring (54) is arranged in the middle guide ring groove (52).

4. A pressure compensation device for an underwater motor according to claim 3, characterized in that: The sealing groove (51) comprises a first waterproof groove (511), a second waterproof groove (512), a first oil-proof groove (513) and a front step ring groove (514) which are arranged in sequence; a first waterproof U-shaped ring (531) is inserted into the first waterproof groove (511); a second waterproof U-shaped ring (532) is inserted into the second waterproof groove (512); a first oil-proof U-shaped ring (533) is inserted into the first oil-proof groove (513); and a front step ring (534) is inserted into the front step ring groove (514).

5. The pressure compensation device of an underwater motor according to claim 4, characterized in that: The middle guide ring groove (52) comprises a middle first guide ring groove (521) and a middle second guide ring groove (522); the middle first guide ring groove (521) is located between the first oil-proof groove (513) and the front step ring groove (514); a middle first guide ring (541) is inserted into the middle first guide ring groove (521); the middle second guide ring groove (522) is located on an extension line of the front step ring groove (514) away from the first oil-proof groove (513); and a middle second guide ring (542) is inserted into the middle second guide ring groove (522).

6. A pressure compensation device for an underwater motor according to claim 1 or 2, characterized in that: A rear guide ring groove (61) and a rear step ring groove (62) are distributed on the outer surface of the rear piston (6), a rear guide ring (63) is inserted into the rear guide ring groove (61), and a rear step ring (621) is inserted into the rear step ring groove (62).

7. A pressure compensation device for an underwater motor according to claim 6, characterized in that: The rear guide ring groove (61) comprises a rear first guide ring groove (611) and a rear second guide ring groove (612); a rear stepped ring groove (62) is provided between the rear first guide ring groove (611) and the rear second guide ring groove (612); a rear first guide ring (631) is inserted into the rear first guide ring groove (611); and a rear second guide ring (632) is inserted into the rear second guide ring groove (612).

8. The pressure compensation device of an underwater motor according to claim 7, characterized in that: The flange end (12) comprises an end face sealing groove (121) and two radial sealing grooves (122); an end face sealing ring (123) is arranged in the end face sealing groove (121), and radial sealing rings (124) are arranged in the radial sealing grooves (122).

9. A pressure compensation device for an underwater motor according to claim 1 or 2, characterized in that: A threaded hole (64) is provided in one end of the rear piston (6) close to the motor winding oil chamber (7), and one end of a water leakage sensor (641) is inserted into the threaded hole (64).

10. A pressure compensation device for an underwater motor according to claim 1 or 2, characterized in that: The outer surface of the end of the water-permeable cover (4) away from the seawater spring (2) is covered with a filter cover (42), and a plurality of filter holes (421) are evenly distributed on the filter cover (42); and a scraper ring (55) is provided on the end of the front piston (5) close to the seawater spring (2).

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