CN220039823U - Nacelle propeller bearing assembly and stern seal test device - Google Patents

Abstract

The utility model relates to a nacelle propeller bearing assembly and a stern sealing test device, which comprise a driving device, an axial force loading device, a test piece supporting bench, a simulation shafting, a radial force loading device, a bench base, a heating ventilation device, a hydraulic device and a cooling water device, wherein the test piece supporting bench is arranged on the bench base; the driving device is arranged on the rack base, connected with the analog shafting and drives the analog shafting to rotate; the axial force loading device is arranged at one end of the tested piece supporting rack and is connected with the simulation shafting; the radial force loading device is arranged at the other end of the rack base, is connected with the simulated shafting and is used for applying radial force load to the shafting support system; the heating ventilation device, the hydraulic device and the cooling water device are arranged on one side of the rack base and are connected with the reserved interface of the test device. The utility model can simulate the bearing assembly and stern sealing operation condition, verify that the design performance and reliability meet the design index requirements, and reduce the technical risk of pod propeller development.

Description

Nacelle propeller bearing assembly and stern seal test device

Technical Field

The utility model relates to a ship power propulsion system, in particular to a nacelle propeller bearing assembly and a stern seal test device.

Background

In recent years, the electric propulsion technology of ships has been rapidly developed, and the pod propeller becomes the preference of the main propeller of the electric propulsion ship by virtue of the advantages of flexible operation, simple structure, small vibration, low noise, small cabin occupation space and the like.

The propulsion motor of the nacelle propeller is arranged in the underwater cabin and directly drives the propeller through the output shaft to generate power required by ship navigation, so that a stern sealing device is required to be equipped to prevent seawater from entering the propulsion motor cabin through the output shaft; at the same time, the load of the propeller is transferred to the suspension post, the swivel module and the hull through the bearing assembly. Thus, the performance and reliability of the bearing assembly and stern seal greatly determine the operational stability of the pod-propeller.

At present, foreign areas are mature in the aspects of pod propeller design and application, a large number of reliable methods and results are formed for pod propeller bearing assemblies and stern sealing designs, a plurality of parts and test platforms of the whole machine are provided, and meanwhile, verification and improvement are carried out through a large number of real ship application data. The development of the pod propeller is still in an exploration stage in China, particularly, a high-power pod propeller is not finished, one of the main reasons is that the design of a bearing component and a stern seal of the high-power pod propeller is designed and related test technology is deficient, and the running performance and reliability requirements of the high-power pod propeller cannot be guaranteed only by virtue of the experience design and theoretical calculation of research personnel; meanwhile, the whole machine of the pod propeller is huge in land or real ship test scale, risk and cost, and the time node is relatively late in the development process. Therefore, a test device capable of better simulating the operation conditions of the bearing assembly and the stern seal is required to be developed and designed, the design performance and the operation reliability of the bearing assembly and the stern seal are verified, the key technology is solved in the development process, and the technical risk of the development of the nacelle propeller is reduced.

Disclosure of Invention

The utility model provides a test device for a bearing assembly and a stern seal of a nacelle propeller, which simulates the running conditions of the bearing assembly and the stern seal, verifies that the design performance and reliability of the test device meet the design index requirements, and reduces the technical risk of nacelle propeller development. The test device adopts a driving device to drive a shafting to rotate, adopts a simulation shafting to simulate the physical characteristics of a propulsion motor shafting, adopts a heating ventilation device to simulate the temperature environment of a motor cavity, adopts an axial force loading device and a radial force loading device to simulate the load generated by a propeller, adopts a test piece supporting bench, a hydraulic device and a cooling water device to ensure the operation environment of a test piece (a bearing assembly and a stern seal), and adopts an integral bench base to control the influence of a test field on the test device.

In order to achieve the above purpose, the technical scheme of the utility model is as follows: the nacelle propeller bearing assembly and stern sealing test device comprises a driving device, an axial force loading device, a tested piece supporting rack, a simulated shafting, a radial force loading device, a rack base, a heating ventilation device, a hydraulic device and a cooling water device, wherein the tested piece supporting rack is arranged on the rack base; the driving device is arranged on the rack base, connected with the analog shafting and drives the analog shafting to rotate; the axial force loading device is arranged at one end of the tested piece supporting rack, is connected with the simulated shafting and is used for applying axial force load to the shafting supporting system; the radial force loading device is arranged at the other end of the rack base, connected with the simulated shafting and used for applying radial force load to the shafting support system; the heating ventilation device, the hydraulic device and the cooling water device are arranged on one side of the rack base and are connected with the reserved interface of the test device.

Further, a tested piece is arranged in the tested piece supporting rack, and the tested piece is connected with the simulation shafting.

Further, the driving device is composed of a driving motor, a motor mounting bracket and an elastic coupling, wherein the driving motor is mounted on the motor mounting bracket and is connected with the simulation shafting through the elastic coupling.

The axial force loading device consists of an oil cylinder end cover, a piston guide post, an oil cylinder piston, a thrust aligning roller bearing, an oil cylinder shell, an oil lubricating cavity shell and a bearing spacer ring, and is arranged on a test piece supporting rack through the oil cylinder shell, and the generated axial force is transmitted to the bearing assembly through a simulation shafting; the thrust oil cylinder is formed by the oil cylinder end cover, the piston guide post, the oil cylinder piston and the oil cylinder shell, hydraulic oil is filled in the thrust oil cylinder, and axial force is generated through pressurization of a hydraulic device.

Further, the tested piece support rack consists of a thrust bearing end support frame, a support shell, a bearing end support frame and a dynamic seal support plate, wherein the thrust bearing end support frame and the axial force loading device form a thrust bearing end cooling water tank, and the thrust bearing end cooling water tank is communicated with circulating cooling water and is used for simulating the external seawater environment of the thrust bearing assembly; the supporting shell adopts a Harvard structure, is convenient to install and disassemble, surrounds the simulated shafting, and forms a simulated motor cavity with the bearing assembly; the heating and ventilation device is connected with the support shell and is used for simulating the temperature of the motor cavity to be maintained at the temperature of the propulsion motor cavity of the nacelle propeller under the test working condition, so as to form a test thermal load environment; the supporting shaft end supporting frame and the dynamic seal supporting plate form a supporting shaft end cooling water tank, and the supporting shaft end cooling water tank is communicated with circulating cooling water and used for simulating the external seawater environment of the supporting bearing assembly of the nacelle propeller and the stern seal.

Further, the simulation shafting comprises propeller shaft, simulation motor rotor, thrust shaft, simulation motor rotor one end thrust shaft, and the other end is connected the propeller shaft for to the bearing assembly and the stern sealed transmission load under the test operating mode of being tested.

Further, the radial force loading device comprises a radial force loading support frame, a radial force loading connecting plate, a hydraulic cylinder, a bearing seat and a self-aligning roller bearing, wherein the radial force loading support frame is arranged on a rack base, a radial motion module formed by the radial force loading connecting plate, the bearing seat and the self-aligning roller bearing is arranged on a propeller shaft, and the hydraulic cylinder is arranged on two sides of the propeller shaft of the simulation shafting and is connected with the radial force loading support frame and the radial force loading connecting plate.

Further, the radial force loading support frame is provided with a sliding rail for guiding radial movement of the radial movement module, so that local overheating or damage caused by unbalanced stress of the self-aligning roller bearing due to mechanical and load errors is avoided; the single or multiple hydraulic cylinders on both sides are of identical parameters and are connected to the same hydraulic device to reduce the difference in radial tension on both sides.

Further, the bench base adopts an integral structure.

The beneficial effects of the utility model are as follows:

the nacelle propeller bearing assembly and stern seal test device provided by the utility model can be used for test verification: vibration, lubrication, heating, play, service life and other parameters of the nacelle propeller thrust bearing and support bearing operation, strength, material selection, structural form and the like of mechanical accessories of the thrust bearing and the support bearing, leakage amount of stern seal, sealing material selection, spring design, structural design, pneumatic design and the like (the system principle is shown in figure 5). The test device comprises 9 primary modules: the device comprises a driving device, an axial force loading device, a tested piece supporting bench, a simulation shafting, a radial force loading device, a bench base, a heating and ventilation device, a hydraulic device and a cooling water device. The interfaces of the modules are clear, the assembly period of the modules can be greatly shortened, faults can be conveniently and timely found, the fault modules are replaced, and the maintenance period is shortened. In addition, the testing device has excellent universality, and can conveniently replace bearing assemblies and stern seals of pod propellers with different power levels to carry out related tests.

The driving device of the test device is connected with the simulation shafting by adopting the elastic coupling, so that the influence of vibration generated by the operation of the driving motor and the shafting misalignment on the test can be avoided.

The axial force loading device of the test device is arranged on a test piece supporting rack through a connecting flange, and generated axial force is transmitted to a shafting supporting system through a simulation shafting. The oil cylinder shell, the oil cylinder piston and the oil cylinder end cover form a thrust oil cylinder, and thrust load is transmitted through the thrust self-aligning roller bearing. The piston guide post can prevent the cylinder piston from being blocked due to uneven stress. The cylinder diameter, hydraulic oil pressure, structural rigidity and strength and the type of the thrust bearing can be adjusted according to the test working condition requirements and the performance parameters of the hydraulic device.

The tested piece supporting rack of the test device not only plays a role in supporting a tested piece, but also builds a seawater environment and a thermal load environment of a test. The thrust bearing assembly is arranged on a support frame at the thrust bearing end, and forms a cooling water cabin at the thrust bearing end with the axial thrust load loading device, and the cooling water device is used for circulating cooling water to simulate the seawater environment of the thrust bearing assembly of the nacelle propeller. The simulated motor cavity is formed by the thrust bearing assembly and the supporting bearing assembly, the temperature in the cavity is maintained at the temperature of the cabin propeller propulsion motor cavity under the test working condition by using the heating ventilation device, and a test thermal load environment is formed. The supporting bearing component and the stern seal are arranged on the supporting frame at the supporting bearing end, and the supporting bearing end cooling water cabin and the dynamic seal supporting plate form a seawater environment for circulating cooling water by using a cooling water device to simulate the supporting bearing component of the nacelle propeller and the stern seal.

The simulated shafting of the test device transmits load under test working conditions to the bearing assembly and the stern seal. The propeller shaft, the simulated motor rotor and the thrust shaft are designed according to the rigidity, the mass, the rotational inertia and the thermal expansion of a motor shaft of the nacelle propeller, so that the bearing and stern seal loading condition under the test working condition is basically consistent with the actual operation working condition of the nacelle propeller.

The radial force generated by the radial force loading device of the test device acts on the propeller radial resultant force point on the propeller shaft. The radial force loading support frame bears radial tension, and the sliding rail is designed to provide guidance for radial movement of the radial movement module, so that local overheating or damage caused by unbalanced stress of the self-aligning roller bearing due to mechanical and load errors can be avoided. The hydraulic cylinder, the bearing seat and the self-aligning roller bearing can be designed and selected according to the installation space and the radial load of the test limit and the equipment quantity is determined.

The bench base of the test device adopts an integral design, so that the difficulty in shafting alignment and the influence of the field change on the test device can be reduced.

The heating ventilation device, the hydraulic device and the cooling water device of the test device are respectively designed and selected according to test working conditions, and the requirements of tests on air temperature, hydraulic oil pressure, cooling water flow, temperature and pressure are met.

Drawings

FIG. 1 is a schematic view of a nacelle propeller bearing assembly and stern seal test apparatus of the present utility model;

FIG. 2 is a view in the direction A of FIG. 1;

FIG. 3 is a schematic illustration of an axial force loading device;

FIG. 4 is a schematic view of a specimen support gantry;

FIG. 5 is a schematic view of a radial force loading device;

FIG. 6 is a view in the direction A of FIG. 5;

fig. 7 is a schematic diagram of the system principle of the present utility model.

Detailed Description

The utility model will be further described with reference to the drawings and examples.

As shown in fig. 1 to 7, the nacelle propeller bearing assembly and the stern sealing test device of the utility model are composed of nine modules, namely a driving device 1, an axial force loading device 2, a tested piece supporting rack 3, a simulated shafting 4, a radial force loading device 5, a rack base 6, a heating ventilation device 7, a hydraulic device 8 and a cooling water device 9, wherein the nine modules are shown in fig. 1 and 2. The tested piece 10 (bearing assembly and stern seal) is arranged in the tested piece supporting bench 3, and the tested piece supporting bench 3 is arranged on the bench base 6; the driving device 1 is arranged on the rack base 6, is connected with the analog shafting 4 and drives the analog shafting 4 to rotate; the axial force loading device 2 is arranged at one end of the tested piece supporting rack 3 and applies axial force load to the shafting supporting system through the simulation shafting 4; the radial force loading device 5 is arranged on the rack base 6 and applies radial force load to the shafting support system through the simulated shafting 4; the heating and ventilation device 7, the hydraulic device 8 and the cooling water device 9 are arranged on one side of the rack base 6 and are connected with a reserved interface of the test device. The developed nacelle propeller bearing assembly and stern seal test device can verify the performance of the nacelle propeller bearing assembly and stern seal in multiple aspects.

The driving device 1 mainly comprises a driving motor, a motor mounting bracket and an elastic coupling. The coupling should select the elastic coupling to avoid driving motor operation and the vibration that the shafting is not centered to produce to experimental influence. And selecting a proper driving motor and an elastic coupling according to the friction moment born by the simulated shafting 4, the rotational inertia of the simulated shafting 4 and the rotating speed requirement of the test working condition.

The axial force loading device 2 mainly comprises an oil cylinder end cover 2a, a piston guide post 2b, an oil cylinder piston 2c, a thrust self-aligning roller bearing 2d, an oil cylinder shell 2e, an oil lubricating cavity shell 2f and a bearing spacer ring 2g, and is shown in figure 3. The axial force loading device 2 is mounted on the specimen support stand 3 through the cylinder housing 2e, and the generated axial force is transmitted to the bearing assembly through the dummy shafting 4. The cylinder end cover 2a, the piston guide post 2b, the cylinder piston 2c and the cylinder shell 2e form a thrust cylinder, the inside of the thrust cylinder is filled with hydraulic oil, and the thrust cylinder is pressurized by the hydraulic device 8 to generate axial force. The piston guide post 2b can prevent the cylinder piston from being blocked due to uneven stress. And designing the cylinder diameter, hydraulic oil pressure, structural strength and rigidity of the axial force loading device according to the test working condition requirement and the performance parameter of the hydraulic device 8, and selecting a proper thrust bearing.

The tested piece supporting bench 3 mainly comprises a thrust bearing end supporting frame 3a, a supporting shell 3b, a supporting bearing end supporting frame 3c and a dynamic sealing supporting plate 3d, and is shown in the figure 3. The specimen support stand 3 not only plays a role in supporting the specimen, but also constructs a seawater environment and a heat load environment for the test. The thrust bearing end support frame 3a and the axial force loading device 2 form a thrust bearing end cooling water tank. And circulating cooling water is introduced into the cooling water cabin at the thrust bearing end, so as to simulate the external seawater environment of the thrust bearing assembly. The supporting shell 3b adopts a Harvard design, is convenient to install and disassemble, and surrounds the simulation shafting 4 therein to form a simulation motor cavity together with the bearing assembly. The heating and ventilation device 7 is connected with the support shell 3b, and maintains the temperature of the simulated motor cavity at the temperature of the propulsion motor cavity of the nacelle propeller under the test working condition, so as to form a test thermal load environment. The supporting shaft bearing end supporting frame 3c and the dynamic sealing supporting plate 3d form a supporting shaft bearing end cooling water tank. The supporting shaft bearing end cooling water cabin is communicated with circulating cooling water, and the external seawater environment of the supporting bearing assembly of the pod propeller and the stern seal is simulated.

The simulation shafting 4 mainly consists of a propeller shaft, a simulation motor rotor and a thrust shaft. The simulated shafting 4 transfers load under test conditions to the bearing assembly and stern seal. The propeller shaft, the simulated motor rotor and the thrust shaft are designed according to the rigidity, the mass, the rotational inertia and the thermal expansion of a motor shaft of the nacelle propeller, so that the bearing assembly and the stern seal loading condition under the test working condition are basically consistent with the actual operation working condition of the nacelle propeller.

The radial force loading device 5 mainly comprises a loading support frame 5a, a loading connecting plate 5b, a hydraulic cylinder 5c, a bearing seat 5d and a self-aligning roller bearing 5e, and is shown in figures 5 and 6. The radial force generated by the radial force loading means 5 acts on the propeller shaft at the point of resultant radial force of the propeller. The radial force loading support frame 5a is installed on the rack base 6, the radial motion module composed of the radial force loading connection plate 5b, the bearing seat 5d and the aligning roller bearing 5e is installed on the propeller shaft 4a, and the hydraulic cylinders 5c are arranged on two sides of the propeller shaft 4a and are connected with the radial force loading support frame 5a and the radial force loading connection plate 5b. The radial force loading support 5a bears the radial tension, and the sliding rail is designed to provide guidance for the radial movement of the radial movement module, so that the self-aligning roller bearing 5e is prevented from being locally overheated or damaged due to unbalanced stress caused by mechanical and load errors. The two side 2 or more hydraulic cylinders 5c are of identical parameters and are connected to the same hydraulic device 8 to reduce the difference in radial tension on both sides. The hydraulic cylinder 5c, the bearing housing 5d and the self-aligning roller bearing 5e are designed and selected and the number of equipment is determined according to the installation space and the radial load of the test limit.

The bench base 6 adopts an integral design, so that the difficulty in shafting alignment and the influence of environmental change of a test site on the test device are reduced. The heating ventilation device 7, the hydraulic device 8 and the cooling water device 9 are respectively designed and selected according to test working conditions, so that the requirements of tests on the air temperature of a simulated motor cavity, the oil pressure of an axial force oil cylinder and a radial force hydraulic cylinder, the water flow and the temperature of a cooling water cabin at the thrust and supporting shaft ends and the water pressure of a stern sealing water are met.

Example 1: according to the utility model content stated by the nacelle propeller bearing assembly and the stern sealing test device, a 10 MW-level nacelle propeller bearing assembly and a stern sealing test device are designed and developed. The device is divided into a driving device, an axial force loading device, a tested piece supporting rack, a simulation shafting, a radial force loading device, a rack base, a heating and ventilation device, a hydraulic device and a cooling water device in composition.

The driving device consists of a 315KW variable frequency motor and an elastic coupling with rated torque of 20 kNm.

The axial force loading device can generate rated thrust of 1200kN, and the selected bearing is a single 29452 thrust self-aligning roller bearing.

The tested piece support rack meets the size installation requirements of the 10 MW-level pod propeller bearing assembly and the stern seal, the simulated motor cabin can effectively simulate the thermal load environment of the 10 MW-level pod propeller propulsion motor cabin, and the cooling water cabin at the thrust bearing end and the supporting bearing end can effectively simulate the seawater environment.

The rigidity, the mass, the rotational inertia and the thermal expansion of the simulated shafting are basically consistent with those of a motor shaft of the 10MW pod-propulsion motor, and the bearing assembly and the stern seal loading condition under the test working condition are matched with those of the 10MW pod-propulsion motor in actual operation.

The radial force loading support frame of the radial force loading device is provided with a guide slide rail with excellent performance, 2 hydraulic cylinders capable of respectively generating 235kN tensile force are selected, 1 set of 23044K+H3044 self-aligning roller bearings with the tight sleeves are selected, and 1 SNL3044 bearing seat is selected.

The bench base is an integral base which is integrally cast and processed, the length and width dimensions are 10m multiplied by 3m, and the bench base can accommodate a 10 MW-level pod propeller bearing assembly and a stern sealing test device, so that the difficulty in shafting alignment and the influence of the field environment change of the test on the test device are effectively reduced.

The heating and ventilation device adopts an air duct type heater with rated power of 25kW, and the temperature in the cavity of the simulation motor can be adjusted between 55 ℃ and 75 ℃.

The hydraulic device is provided with 2 sets of hydraulic pump sets, the rated pressure of the axial thrust loading hydraulic pump set is 5MPa, and the rated pressure of the radial force loading hydraulic pump set is 10MPa.

The cooling water flow rate of the cooling water device is 30t/h, the cooling water temperature is less than 36 ℃, the water pressure is 0.1MPa, and the seawater cooling environment of the shafting support system, the water lubrication environment and the water pressure environment of the stern sealing device are effectively simulated.

By using various types of sensors and instruments, the 10MW pod propeller bearing assembly and the stern seal test device verify that the thrust of a propulsion motor and the running vibration, lubrication, heating, play and service life of a supporting bearing are in the design range, verify that the strength, material selection and structural form of mechanical accessories of the thrust and the supporting bearing meet the requirements, and verify the rationality of stern seal leakage, sealing material selection, spring design, structural design and pneumatic design.

Claims (9)

1. A nacelle propeller bearing assembly and stern seal test apparatus characterized in that: the device comprises a driving device, an axial force loading device, a tested piece supporting rack, a simulation shafting, a radial force loading device, a rack base, a heating and ventilation device, a hydraulic device and a cooling water device, wherein the tested piece supporting rack is arranged on the rack base; the driving device is arranged on the rack base, connected with the analog shafting and drives the analog shafting to rotate; the axial force loading device is arranged at one end of the tested piece supporting rack, is connected with the simulated shafting and is used for applying axial force load to the shafting supporting system; the radial force loading device is arranged at the other end of the rack base, connected with the simulated shafting and used for applying radial force load to the shafting support system; the heating ventilation device, the hydraulic device and the cooling water device are arranged on one side of the rack base and are connected with the reserved interface of the test device.

2. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: and the tested piece is arranged in the tested piece support rack and is connected with the simulation shafting.

3. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the driving device consists of a driving motor, a motor mounting bracket and an elastic coupling, wherein the driving motor is mounted on the motor mounting bracket and is connected with the simulation shafting through the elastic coupling.

4. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the axial force loading device consists of an oil cylinder end cover, a piston guide post, an oil cylinder piston, a thrust aligning roller bearing, an oil cylinder shell, an oil lubricating cavity shell and a bearing spacer ring, and is arranged on a tested piece support rack through the oil cylinder shell, and the generated axial force is transmitted to the bearing assembly through a simulation shafting; the thrust oil cylinder is formed by the oil cylinder end cover, the piston guide post, the oil cylinder piston and the oil cylinder shell, hydraulic oil is filled in the thrust oil cylinder, and axial force is generated through pressurization of a hydraulic device.

5. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the tested piece support rack consists of a thrust bearing end support frame, a support shell, a bearing end support frame and a dynamic seal support plate, wherein the thrust bearing end support frame and the axial force loading device form a thrust bearing end cooling water tank, and the thrust bearing end cooling water tank is communicated with circulating cooling water and is used for simulating the external seawater environment of a thrust bearing assembly; the supporting shell adopts a Harvard structure, is convenient to install and disassemble, surrounds the simulated shafting, and forms a simulated motor cavity with the bearing assembly; the heating and ventilation device is connected with the support shell and is used for simulating the temperature of the motor cavity to be maintained at the temperature of the propulsion motor cavity of the nacelle propeller under the test working condition, so as to form a test thermal load environment; the supporting shaft end supporting frame and the dynamic seal supporting plate form a supporting shaft end cooling water tank, and the supporting shaft end cooling water tank is communicated with circulating cooling water and used for simulating the external seawater environment of the supporting bearing assembly of the nacelle propeller and the stern seal.

6. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the simulation shafting consists of a propeller shaft, a simulation motor rotor and a thrust shaft, wherein one end of the simulation motor rotor is connected with the thrust shaft, and the other end of the simulation motor rotor is connected with the propeller shaft and used for transmitting load under test working conditions to a bearing assembly of a tested piece and stern seal.

7. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the radial force loading device comprises a radial force loading support frame, a radial force loading connecting plate, hydraulic cylinders, bearing seats and self-aligning roller bearings, wherein the radial force loading support frame is arranged on a rack base, a radial motion module formed by the radial force loading connecting plate, the bearing seats and the self-aligning roller bearings is arranged on a propeller shaft, and the hydraulic cylinders are arranged on two sides of the propeller shaft of the simulation shafting and are connected with the radial force loading support frame and the radial force loading connecting plate.

8. The pod propeller bearing assembly and stern seal test apparatus of claim 7 wherein: the radial force loading support frame is provided with a slide rail for guiding radial movement of the radial movement module, so that local overheating or damage caused by unbalanced stress of the self-aligning roller bearing due to mechanical and load errors is avoided; the single or multiple hydraulic cylinders on both sides are of identical parameters and are connected to the same hydraulic device to reduce the difference in radial tension on both sides.

9. The pod propeller bearing assembly and stern seal test apparatus of claim 1 wherein: the bench base adopts an integral structure.