A retractable loading device and testing method for retractable fin stabilizers

Abstract

The present application belongs to the technical field of test benches for marine components, and specifically relates to a retractable and deployable fin stabilizer and a testing method thereof. The device comprises a fin handle, an electric cylinder, a telescopic oil cylinder and a slide rail. The fin handle has a central hole, and a rotating shaft is passed through the central hole. The upper end of the rotating shaft is connected to a retractable mechanism, and the lower end of the rotating shaft is rotatably connected to a mounting platform of the retractable and deployable fin stabilizer. An ear shaft mounting seat is provided on one side of the outer periphery of the fin handle, and a roller mounting seat is provided on the other side. The cylinder body of the telescopic oil cylinder is fixed on the mounting platform, and its push rod is rotatably connected to the ear shaft mounting seat. The bottom of the electric cylinder is fixed on the mounting platform, and a slide rail is installed on the top of its push rod. The roller mounting seat is slidably connected to the slide rail. The retractable and deployable fin stabilizer of the present application is based on the fluid resistance and fluid lift experienced by the fin when the fin is deployed outboard during navigation. It simulates the retractable and deployable mechanism overcoming the fluid load experienced by the fin when the fin is deployed outboard during actual navigation, and can truly and effectively verify the structural stability and retractable capacity of the retractable and deployable mechanism.

Description

Technical Field

[0001] The present invention belongs to the technical field of test benches for marine components, and in particular relates to a retractable loading device and a testing method for retractable fin stabilizers. Background Art

[0002] Fin stabilizers are the most widely used ship roll stabilization devices and can be divided into retractable fin stabilizers and non-retractable fin stabilizers. For retractable fin stabilizers, the retraction and extension process of the fins is achieved through a retraction mechanism. Figure 1 As shown, the retractable fin stabilizer's retraction and extension mechanism A comprises a thrust block A1, a retraction and extension cylinder A2, a thrust rod A3, a sliding sleeve A4, a retraction and extension connecting rod A5, a guide sleeve A6, and a rotating body A7. When the retractable fin stabilizer is not in operation, the fin needs to be retracted into the fin box on the flank of the ship. Oil enters the rod chamber of the retraction and extension cylinder A2, causing the piston rod to move toward the bow. The thrust rods A3 on either side of the piston rod push the sliding sleeve A4 in a linear motion along the guide sleeve A6. The retraction and extension connecting rod A5 then drives the rotating body A7 and other components to rotate toward the stern, thereby retracting the fin into the fin box. When the retractable fin stabilizer is working, oil enters the rodless chamber of the retracting cylinder A2, causing the piston rod to move toward the stern of the ship. The thrust rods A3 on both sides push the sliding sleeve A4 to move linearly along the guide sleeve A6. Through the traction of the retracting connecting rod A5, the rotating body A7 and other components are driven to rotate toward the bow of the ship, thereby extending the fin outboard.

[0003] Because roll stabilization often occurs during navigation, retractable fin stabilizers must overcome external fluid loads during deployment. Existing technology relies solely on theoretical calculations to verify the load capacity during deployment, lacking onshore loading technology. Therefore, a loading device is needed to simulate the actual fluid loads experienced by the retractable fin during navigation, verifying its structural stability and retractability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention proposes a retractable loading device and testing method for retractable fin stabilizers. Based on the fluid resistance and lift experienced by fins deployed outboard during navigation, the device simulates the fluid load experienced by the retractable mechanism during actual navigation to verify the structural stability and retractable capacity of the mechanism. Current simulation equipment often simulates unidirectional forces acting on the device, whereas the forces acting on retractable fin stabilizers during motion are more complex. Retractable fin stabilizers are subject not only to fluid resistance in the opposite direction of motion but also to fluid lift, which changes with motion and can alter both the location and magnitude of the force. Currently, no loading device is available that can simulate such a complex force structure as a retractable fin stabilizer.

[0005] To achieve the above objectives, the present invention provides a retractable loading device and testing method for a retractable fin stabilizer. The retractable loading device is used to simulate the fluid resistance and fluid lift experienced by the retractable mechanism of the fin stabilizer during operation. The retractable loading device is mounted on the bottom of the retractable mechanism and includes a fin handle, an electric cylinder, a telescopic oil cylinder, and a slide rail.

[0006] The fin handle has a center hole, and a rotating shaft passes through the center hole. The upper end of the rotating shaft is connected to the housing mechanism, and the lower end of the rotating shaft is rotatably connected to the mounting platform of the retractable loading device; a trunnion mounting seat is provided on one side of the outer periphery of the fin handle, and a roller mounting seat is provided on the other side; the cylinder body of the telescopic oil cylinder is fixed on the mounting platform, and its push rod is rotatably connected to the trunnion mounting seat; the bottom of the electric cylinder is fixed on the mounting platform, and the slide rail is installed on the top of its push rod, and the roller mounting seat is slidably connected to the slide rail;

[0007] When the retractable and extending mechanism rotates back and forth and drives the fin handle to rotate, the ear shaft mounting seat pushes and pulls the push rod of the telescopic cylinder, and the push rod of the telescopic cylinder generates a reverse torque which is transmitted to the retractable and extending mechanism through the fin handle. The retractable and extending mechanism overcomes the force of the telescopic cylinder to simulate the fluid resistance; the electric cylinder is used to apply a push-pull force to the bottom of the slide rail, so that the force is transmitted to the retractable and extending mechanism through the fin handle. The retractable and extending mechanism overcomes the force of the electric cylinder to simulate the fluid lift.

[0008] Furthermore, the fluid resistance applied by the retractable loading device to the retractable mechanism is determined by the following formula:

[0009] P=0.5AHV 2 L / (NS)

[0010] Where: P is the fluid resistance exerted by the retractable loading device on the retractable mechanism, A is the horizontal projected area of ​​the fin, H is the product of the fluid resistance coefficient when the fin is extended overboard and the seawater density, V is the speed of the ship when the fin is extended overboard, L is the distance from the center of the fin to the fin rotation center, N is the straight-line distance from the center line of the pin shaft in the fin shank trunnion mounting seat to the center line of the center hole of the fin shank, and S is the effective area of ​​the telescopic cylinder.

[0011] Furthermore, the lifting force applied by each electric cylinder to the retracting and extending mechanism is determined by the following formula:

[0012] F=0.5AKV 2 / n

[0013] Where: F is the thrust or pull output on each electric cylinder, A is the horizontal projected area of ​​the fin, K is the fluid lift coefficient when the fin is extended outboard, V is the speed of the ship when the fin is extended outboard, and n is the number of electric cylinders distributed at the bottom of the slide rail.

[0014] Furthermore, the slide rail is an arc-shaped structure, and its cross-section is a U-shaped groove, and the roller mounting seat is located in the U-shaped groove of the slide rail.

[0015] Furthermore, the angle formed by the center of the fin handle and the two ends of the arc-shaped structure of the slide rail is the rotation angle of the retracting mechanism.

[0016] Furthermore, the retractable loading device also includes a roller group; the roller group is installed on the roller mounting seat and abuts against the U-shaped groove of the slide rail.

[0017] Furthermore, the central axis of the arc-shaped structure of the slide rail is colinear with the central axis of the fin handle.

[0018] Furthermore, there are multiple electric cylinders, each of which is arranged at intervals at the bottom of the slide rail; each electric cylinder moves synchronously and outputs the same thrust or pull in sequence; changing the thrust or pull output each time is used to simulate the load change of fluid lift.

[0019] Furthermore, the roller assembly is mounted on both the bottom and the top of the roller mounting base.

[0020] The present invention further provides a method for testing the retractable loading device for a retractable fin stabilizer as described above, comprising the following steps:

[0021] Step 1: After the retracting and loading mechanism is installed, adjust the thrust on the electric cylinder to simulate the fluid lift, which is transmitted to the roller assembly through the slide rail. The roller assembly transmits the simulated fluid lift to the fin handle and then to the retracting and loading mechanism;

[0022] Step 2: Adjust the pressure of the telescopic cylinder to the preset value to make it in a passive loading state;

[0023] Step 3: The retractable mechanism rotates back and forth as preset. The retractable mechanism's rotating body is connected to the rotating shaft. The rotational motion of the rotating body is transmitted to the fin handle through the rotating shaft. The roller assembly in the fin handle rolls back and forth in the slide rail as the retractable mechanism rotates. The fin handle passively compresses or stretches the push rod of the telescopic cylinder, and the push rod transmits the simulated fluid resistance in the reverse direction to the retractable mechanism.

[0024] Step 4: The fluid lift and fluid resistance simulated by the loading device are continuously applied to the retractable mechanism for a predetermined period of time, so that the retractable mechanism is subjected to both the fluid resistance and the fluid lift during the retracting and extending process. The test data is analyzed after the test is completed.

[0025] The beneficial effects of the present invention are:

[0026] First, the structure of the present invention can not only simulate the fluid resistance in the opposite direction of the movement of the fin stabilizer during its movement, but also simulate the influence of different lift forces on the fin stabilizer in the vertical direction when the fin stabilizer moves to different positions. Specifically, the present invention adopts a fin handle, an electric cylinder, a roller group, a telescopic oil cylinder and a slide rail. A rotating shaft is installed in the middle of the fin handle, which is rotatably connected to the retraction mechanism through the rotating shaft. An ear shaft mounting seat and a roller mounting seat are respectively provided on both sides of the outer periphery of the fin handle. The ear shaft mounting seat is rotatably connected to the push rod of the telescopic oil cylinder through a pin shaft. A plurality of electric cylinders are spaced apart at the bottom of the slide rail and fixedly connected to the bottom of the slide rail, so that the roller group drives the roller mounting seat of the fin handle to slide in the slide rail; the electric cylinder applies a vertical upward thrust and a vertical downward pull to the bottom of the slide rail. When the retraction mechanism reciprocates, The fin handle is driven to rotate, and the hydraulic oil pressure of the telescopic cylinder is overcome by the retractable mechanism to simulate fluid resistance, while the force applied by the electric cylinder to the bottom of the slide rail is transmitted to the retractable mechanism through the fin handle, and the retractable mechanism overcomes the force of the electric cylinder to simulate fluid lift. Based on the fluid resistance and fluid lift experienced by the fins when the fins are extended outboard during sailing, the present invention can simulate the retractable mechanism overcoming the fluid load experienced by the fins when the fins are extended outboard during actual sailing, thus solving the problem that the load capacity verification of the current retractable mechanism is still at the theoretical calculation stage. The structural stability and retractable capacity of the retractable mechanism are verified on a test bench.

[0027] Second, the electric cylinder and telescopic oil cylinder of the present invention work synchronously, and the retractable loading device is equipped with a retractable mechanism. The retractable mechanism is arranged according to the actual state. The retractable loading device provides fluid resistance and fluid lift to the retractable mechanism. The retractable mechanism withstands fluid resistance while also bearing fluid lift at different rotational positions. This can effectively verify the fluid load on the fins when the ship is sailing.

[0028] Third, the resistance exerted by the retractable loading device of the present invention on the retractable mechanism is calculated by the formula P = 0.5AHV 2 L / (NS), the lift force exerted by a single electric cylinder on the retracting and extending mechanism is obtained by the formula F=0.5AKV2 / n, where A is the horizontal projected area of ​​the fin, H is the product of the fluid resistance coefficient and the seawater density when the fin is extended outboard, V is the speed of the ship when the fin is extended outboard, L is the distance from the center of the fin extension to the center of the fin rotation, N is the distance from the center of the pin of the trunnion mounting seat of the fin handle 1 to the center of the rotating shaft 2, S is the effective area of ​​the telescopic cylinder 5, K is the fluid lift coefficient when the fin is extended outboard, and n is the number of electric cylinders 3. This makes the test results more accurate. Based on the principle of the calculation formula and different retracting and extending mechanism structures, by adjusting the size of the retracting and extending loading device and the relative positions of each component, it is possible to verify a variety of retracting and extending mechanisms;

[0029] Fourth, the loading force applied by the retractable loading device of the present invention can be changed according to the speed at which the fin stabilizer is extended outboard and the sailing speed of the ship. The faster the speed at which the fin stabilizer is extended outboard and the sailing speed of the ship are, the greater the fluid resistance and fluid lift applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the retractable fin stabilizer retractable mechanism of the prior art;

[0031] Figure 2 is a front view of a retractable loading device according to an embodiment of the present invention;

[0032] Figure 3 is a top view of a retractable loading device according to an embodiment of the present invention;

[0033] Figure 4 2. It is a structural diagram of a retractable loading device equipped with a retractable mechanism according to an embodiment of the present invention;

[0034] Figure 5 The fluid resistance test data of the retractable loading device equipped with the retractable mechanism according to the embodiment of the present invention;

[0035] Figure 6 The fluid lift test data of the retractable loading device equipped with the retractable mechanism according to the embodiment of the present invention;

[0036] Figure 7 This is the actual object of the retractable loading device of the embodiment of the present invention Figure 1 ;

[0037] Figure 8 This is the actual object of the retractable loading device of the embodiment of the present invention Figure 2 ;

[0038] Figure 9 This is the actual object of the retractable loading device of the embodiment of the present invention Figure 3 .

[0039] Among them, A-retraction and extension mechanism; A1-thrust block; A2-retraction and extension cylinder; A3-thrust rod; A4-sliding sleeve; A5-retraction and extension connecting rod; A6-guide sleeve; A7-rotating body; 1-fin handle; 2-rotating shaft; 3-electric cylinder; 4-roller assembly; 5-telescopic cylinder; 6-cylinder mounting seat; 7-slide rail. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] The terms "up", "down", "left", "right", "front", and "back" in this application are based on the positional relationships shown in the accompanying drawings. The corresponding positional relationships may vary depending on the drawings, and should not be construed as limiting the scope of protection.

[0042] In this application, the terms "installed," "connected," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, integral connection, mechanical connection, electrical connection, or mutual communication. They can also be directly connected or indirectly connected through an intermediate medium. They can also refer to internal communication between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] This invention describes a retractable loading device and testing method for retractable fin stabilizers. The loading device and the retractable mechanism are both installed on a test bench, with the retractable mechanism arranged as designed. A ship's navigation is subject to external flow field disturbances and changes in the ship's longitudinal attitude. When retracting and deploying, the fins generate a certain angle of attack with the external flow field, causing the fins to be subjected to fluid resistance and lift when deployed outboard. These fluid resistance and lift act as the fluid loads on the fin's retractable mechanism. The loading device of this invention verifies the structural stability and retractable capacity of the retractable mechanism by simulating the fluid loads the retractable mechanism experiences when the fins are deployed outboard during actual navigation.

[0044] Refer to the instruction manual Figure 2-4 The retractable loading device of the present invention is connected to the rotating body of the retractable mechanism A and is located below the retractable mechanism A. The retractable loading device includes a fin handle 1, a rotating shaft 2, an electric cylinder 3, a roller group 4, a telescopic oil cylinder 5, an oil cylinder mounting seat 6, a slide rail 7 and a rotating shaft mounting seat.

[0045] The shaft mounting base is fixed to the base plate of the retractable loading device and contains a bearing. A vertically mounted shaft 2 is connected to the bearing in the shaft mounting base at one end and to the rotating body of the retractable mechanism A at the other end. The fin handle 1 is sleeved on the shaft 2, located between the shaft mounting base and the rotating body of the retractable mechanism A. The fin handle 1 and the shaft 2 are splined together. The fin handle 1 has an internal spline hole, and the shaft 2 is provided with external splines.

[0046] A trunnion mounting seat is provided on one side of the periphery of the fin handle 1, and a roller mounting seat is provided on the side opposite to the trunnion mounting seat. In this embodiment, the roller mounting seat is higher than the trunnion mounting seat.

[0047] The trunnion mounting seat of the fin handle 1 is connected to the push rod of the telescopic cylinder 5 via a pin. During telescopic operation, the push rod of the telescopic cylinder 5 rotates around the pin in the trunnion mounting seat of the fin handle 1. The cylinder body of the telescopic cylinder 5 is fixedly mounted on the cylinder mounting seat 6, which is fixed to the bottom plate of the retractable loading device. The telescopic cylinder 5 is a passive push-pull cylinder.

[0048] The roller group 4 is installed on the roller mounting seat of the fin handle 1. The slide rail 7 is an arc-shaped structure with a U-shaped groove in cross section. The roller mounting seat of the fin handle 1 is located in the U-shaped groove of the slide rail 7. The roller group 4 abuts against the bottom surface of the U-shaped groove of the slide rail 7. The roller mounting seat of the fin handle 1 slides and displaces in the U-shaped groove of the slide rail 7 through the roller group 4. Its sliding trajectory is the arc of the arc-shaped structure. The angle formed by the center of the rotating shaft 2 to the two ends of the arc-shaped structure of the slide rail 7 is the rotation angle of the retracting mechanism A.

[0049] by Figure 3 Taking the state shown as an example, the thrust rod of the retracting and extending mechanism A pushes the sliding sleeve to move back and forth along the guide sleeve, thereby driving the rotating body and other components of the retracting and extending mechanism A to rotate toward the stern or bow of the ship. The rotating body of the retracting and extending mechanism A drives the rotating shaft 2 to rotate, and the roller group 4 drives the roller mounting seat of the fin handle 1 to rotate and slide in the slide rail 7, so that the ear shaft mounting seat of the fin handle 1 pushes and pulls the push rod of the telescopic oil cylinder 5. The push rod of the telescopic oil cylinder 5 is passively compressed or stretched to generate a reverse torque on the fin handle 1, and then transmitted to the retracting and extending mechanism A connected to the rotating shaft 2. The retracting and extending mechanism A overcomes the hydraulic oil pressure of the telescopic oil cylinder 5. This process is used to simulate the actual navigation process. When the fin is released overboard or recovered, the retracting and extending mechanism A is subject to fluid resistance. Instruction manual attached Figure 5 The fluid lift test data of the retractable loading device of the present invention equipped with the retractable mechanism.

[0050] The fluid resistance P applied by the retractable loading device of the present invention to the retractable mechanism is determined by the following formula:

[0051] P=0.5AHV 2 L / (NS)

[0052] Where: A is the horizontal projection area of ​​the fin, H is the product of the fluid resistance coefficient and the seawater density when the fin is extended outboard, V is the speed of the ship when the fin is extended outboard, L is the distance from the center of the fin extension (the distance from the end face of the fin tip to the end face of the fin root is the fin extension) to the center of the fin rotation, N is the distance from the center of the pin of the trunnion mounting seat of the fin handle 1 to the center of the rotating shaft 2, and S is the effective area of ​​the telescopic cylinder 5.

[0053] There are multiple electric cylinders 3, which are spaced apart at the bottom of the slide rail 7. The electric cylinders 3 have a telescopic structure. One end of the push rod of the electric cylinder 3 is connected to the bottom of the slide rail 7, and the other end of the housing is installed on the bottom plate of the retractable loading device. The multiple electric cylinders 3 work synchronously to apply upward thrust and downward pull to the bottom of the slide rail 7. The force is transmitted to the retractable mechanism A through the roller group 4, the fin handle 1 and the rotating shaft 2. This process is used to simulate the fluid lift force that the retractable mechanism A experiences when overcoming the water flow fluctuations when the fin is released outboard during actual navigation. Figure 6 The fluid lift test data of the retractable loading device of the present invention equipped with the retractable mechanism.

[0054] n electric cylinders 3 are distributed at intervals at the bottom of the slide rail 7. Each electric cylinder 3 outputs the same thrust or pull. During the output of the thrust or pull, the magnitude of the output force of the electric cylinder 3 is varied to simulate the load change of the fluid lift. The thrust or pull F output by each electric cylinder 3 is determined by the following formula:

[0055] F=0.5AKV 2 / n

[0056] Wherein: A is the horizontal projection area of ​​the fin, K is the fluid lift coefficient when the fin is extended outboard, V is the speed of the ship when the fin is extended outboard, and n is the number of electric cylinders 3.

[0057] The retractable loading device of this embodiment also includes a test bench, which includes a base plate, a partition plate, and side plates. The partition plate is arranged above the base plate, and the partition plate and the base plate are connected by multiple side plates. The shaft mounting seat, multiple electric cylinders 3, and the cylinder mounting seat 6 are respectively fixedly mounted on the base plate. The fin handle 1, roller assembly 4, telescopic cylinder 5, and slide rail 7 are located between the partition plate and the base plate. One end of the rotary body of the recovery mechanism is fixedly mounted on the bottom of the partition plate and connected to the rotating shaft 2. The thrust block, recovery cylinder, thrust rod, sliding sleeve, retractable connecting rod, and guide sleeve of the recovery mechanism A are located above the partition plate and connected to the retractable connecting rod.

[0058] The retractable loading device for retractable fin stabilizers of the present invention drives the fin handle 1 to rotate synchronously through the reciprocating rotation of the rotating body of the retractable and retractable fins. Since the telescopic cylinder 5 adopts a passive hydraulic cylinder, the reciprocating rotation of the fin handle 1 overcomes the hydraulic oil pressure of the telescopic cylinder 5 to simulate the retractable fin stabilizer overcoming the fluid resistance encountered during the actual retraction and deployment. While the fin handle 1 reciprocates, the roller mounting seat rotates and slides along the circular arc trajectory of the slide rail 7. The electric cylinder 3 at the bottom of the slide rail 7 moves to transfer force from the fin handle 1 to the retractable and retractable mechanism to simulate the retractable fin stabilizer. During the actual retraction and deployment of the fin, the retraction mechanism overcomes the fluid lift it experiences during deployment at different rotational positions. During the entire loading process, the retraction mechanism withstands the fluid resistance while also bearing the fluid lift at different rotational positions. The arc trajectory of the slide rail 7 matches the rotation angle of the retraction mechanism, effectively simulating the retraction mechanism's ability to overcome the fluid load experienced by the fin when deployed outboard during actual navigation. This solves the problem that the current verification of the retraction mechanism's load capacity is still at the theoretical calculation stage, and verifies the structural stability and retraction capacity of the retraction mechanism through the loading device.

[0059] The present invention also provides a method for testing a retractable loading device for a retractable fin stabilizer, the method comprising:

[0060] Step 1: After the retracting and extending mechanism and the loading device are installed in place, adjust the thrust on the electric cylinder 3 to simulate the fluid lift, and transmit it to the roller group 4 through the slide rail 7. The roller group 4 transmits the simulated fluid lift to the fin handle 1, and then to the retracting and extending mechanism.

[0061] Step 2: Adjust the pressure of the telescopic oil cylinder 5 to a preset value so that it has a passive loading state.

[0062] Step 3: The retracting and extending mechanism rotates back and forth as preset. The rotating body of the retracting and extending mechanism is connected to the rotating shaft 2. The rotational motion of the rotating body is transmitted to the fin handle 1 through the rotating shaft 2. The roller group 4 in the fin handle 1 rolls back and forth in the slide rail 7 as the retracting and extending mechanism rotates. The fin handle 1 passively compresses or stretches the push rod of the telescopic cylinder 5, and the push rod transmits the simulated fluid resistance in reverse to the retracting and extending mechanism.

[0063] Step 4: The fluid lift and fluid resistance simulated by the loading device are continuously applied to the retractable mechanism for a predetermined period of time, so that the retractable mechanism is subjected to both the fluid resistance and the fluid lift during the retracting and extending process. The test data is analyzed after the test is completed.

[0064] The test time of the test method of the loading device in this embodiment is 350 hours.

[0065] The above is only an embodiment of the present invention, and common sense such as the specific structure and characteristics of the scheme are not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claim involved.

Claims

1. A retractable loading device for a retractable fin stabilizer, characterized in that: The retractable loading device is used to simulate the fluid resistance and fluid lift experienced by the retractable mechanism of the fin stabilizer during operation; the retractable loading device is installed at the bottom of the retractable mechanism, and comprises a fin handle (1), an electric cylinder (3), a telescopic oil cylinder (5), and a slide rail (7); The fin handle (1) has a central hole, and a rotating shaft is passed through the central hole, the upper end of the rotating shaft is connected to the retracting and extending mechanism, and the lower end of the rotating shaft is rotatably connected to the mounting platform of the retracting and extending loading device; an ear shaft mounting seat is provided on one side of the periphery of the fin handle (1), and a roller mounting seat is provided on the other side; the cylinder body of the telescopic oil cylinder (5) is fixed on the mounting platform, and its push rod is rotatably connected to the ear shaft mounting seat; the bottom of the electric cylinder (3) is fixed on the mounting platform, and the top of its push rod is installed with the slide rail (7), and the roller mounting seat is slidably connected to the slide rail (7); The slide rail (7) is an arc-shaped structure, and its cross section is a U-shaped groove. The roller mounting seat is located in the U-shaped groove of the slide rail (7). The angle formed by the center of the fin handle (1) and the two ends of the arc-shaped structure of the slide rail (7) is the rotation angle of the retracting mechanism. There are multiple electric cylinders (3), and each of the electric cylinders (3) is arranged at intervals at the bottom of the slide rail (7). The thrust or pull output by each electric cylinder (3) in synchronous motion is the same. The thrust or pull output each time is changed to simulate the load change of the fluid lift. When the retractable mechanism reciprocates and drives the fin handle (1) to rotate, the ear shaft mounting seat pushes and pulls the push rod of the telescopic oil cylinder (5), and the push rod of the telescopic oil cylinder (5) generates a reverse action torque which is transmitted to the retractable mechanism through the fin handle (1). The retractable mechanism overcomes the force of the telescopic oil cylinder (5) to simulate the fluid resistance; the electric cylinder (3) is used to apply a push-pull force to the bottom of the slide rail (7), so that the force is transmitted to the retractable mechanism through the fin handle (1), and the retractable mechanism overcomes the force of the electric cylinder (3) to simulate the fluid lift.

2. The retractable loading device for retractable fin stabilizers according to claim 1, characterized in that: The fluid resistance applied by the retractable loading device to the retractable mechanism is determined by the following formula: P=0.5AHV 2 L / (NS) Where: P is the fluid resistance exerted by the retractable loading device on the retractable mechanism, A is the horizontal projected area of ​​the fin, H is the product of the fluid resistance coefficient when the fin is extended overboard and the seawater density, V is the speed of the ship when the fin is extended overboard, L is the distance from the center of the fin to the fin rotation center, N is the straight-line distance from the center line of the pin shaft in the fin shank trunnion mounting seat to the center line of the center hole of the fin shank, and S is the effective area of ​​the telescopic cylinder.

3. The retractable loading device for retractable fin stabilizers according to claim 1, characterized in that: The lifting force applied by each electric cylinder (3) to the retracting and extending mechanism is determined by the following formula: F=0.5AKV 2 / n Where: F is the thrust or pull output on each electric cylinder, A is the horizontal projected area of ​​the fin, K is the fluid lift coefficient when the fin is extended outboard, V is the speed of the ship when the fin is extended outboard, and n is the number of electric cylinders distributed at the bottom of the slide rail.

4. The retractable and loading device for retractable fin stabilizers according to claim 1, characterized in that: The retractable loading device further comprises a roller group (4); the roller group (4) is mounted on the roller mounting seat and abuts against the U-shaped groove of the slide rail (7).

5. The retractable and loading device for retractable fin stabilizers according to claim 1, characterized in that: The central axis of the arc-shaped structure of the slide rail (7) is collinear with the central axis of the fin handle (1).

6. The retractable and loading device for retractable fin stabilizers according to claim 1, characterized in that: Roller assemblies (4) are installed on the bottom and top of the roller mounting seat.

7. A method for testing a retractable loading device for a retractable fin stabilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: After the retracting and extending mechanism and the loading device are installed in place, the thrust on the electric cylinder (3) is adjusted to simulate the fluid lift, and the thrust is transmitted to the roller assembly (4) through the slide rail (7). The roller assembly (4) transmits the simulated fluid lift to the fin handle (1), and then to the retracting and extending mechanism; Step 2: Adjust the pressure of the telescopic oil cylinder (5) to a preset value so that it has a passive loading state; Step 3: The retracting and extending mechanism rotates back and forth according to the preset setting. The rotating body of the retracting and extending mechanism is connected to the rotating shaft (2). The rotational motion of the rotating body is transmitted to the fin handle (1) through the rotating shaft (2). The roller group (4) in the fin handle (1) rolls back and forth in the slide rail (7) as the retracting and extending mechanism rotates. The fin handle (1) passively compresses or stretches the push rod of the telescopic oil cylinder (5). The push rod transmits the simulated fluid resistance in the reverse direction to the retracting and extending mechanism. Step 4: The fluid lift and fluid resistance simulated by the loading device are continuously applied to the retractable mechanism for a predetermined period of time, so that the retractable mechanism is subjected to both the fluid resistance and the fluid lift during the retracting and extending process. The test data is analyzed after the test is completed.

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