A static balance testing device for ship propellers

Abstract

This invention relates to the technical field of testing equipment, and in particular to a static balance testing device for ship propellers. The device includes a turntable, a fixed arm, and a support shaft. The turntable axis is vertical, the fixed arm is horizontally mounted on the turntable with its length along the radial direction of the turntable, and the support shaft is mounted on the end of the fixed arm away from the turntable. The support shaft axis is vertical and rotates on the fixed arm. A clamping structure for fixing the propeller is provided on the support shaft. By using centrifugal force to detect the propeller's center of gravity shift instead of gravity in traditional methods, a greater force can be provided to the propeller, making it easier to detect small imbalances and improving detection sensitivity. The damping structure can quickly decelerate the propeller, bringing it to a stop as soon as possible, avoiding the need for prolonged natural deceleration in traditional methods, thus significantly shortening the testing time.

Description

Technical Field

[0001] This invention relates to the technical field of testing equipment, and in particular to a static balance testing device for ship propellers. Background Art

[0002] The propeller is a key component of a ship's propulsion system, and its performance directly affects the ship's navigation efficiency and safety. Static balance testing is required during the manufacturing and maintenance of propellers to ensure that imbalances do not cause vibrations or mechanical failures during use. The traditional static balance testing method involves mounting the propeller on a balance frame, allowing it to rotate freely. Due to gravity and friction, the propeller gradually comes to a stop, and its position at rest is recorded. The propeller is then rotated again, and the position at rest is observed to be consistent with the initial resting state. This process is repeated multiple times. When the propeller's center of gravity shifts, its position at rest remains consistent each time; when the center of gravity is on its own axis, the position at rest is inconsistent. This achieves the static balance test of the propeller. However, this testing method is ineffective when the propeller's eccentricity is small, as the force of gravity on the eccentric propeller is constant and relatively small. Therefore, it has low sensitivity and requires the propeller to naturally decelerate and come to a stop, resulting in a long testing time and low efficiency. Summary of the Invention

[0003] In view of at least one of the above-mentioned technical problems, the present invention provides a static balance testing device for ship propellers, the specific technical solution of which is as follows:

[0004] According to a first aspect of the present invention, a static balance testing device for a marine propeller is provided, comprising a turntable, a fixed arm, and a support shaft. The axis of the turntable is vertical, the fixed arm is horizontally mounted on the turntable and the length direction of the fixed arm is along the radial direction of the turntable, the support shaft is mounted on the end of the fixed arm away from the turntable and the axis of the support shaft is vertical, the support shaft rotates on the fixed arm, and a clamping structure for fixing the propeller is provided on the support shaft.

[0005] When the turntable rotates, the propeller undergoes centrifugal motion. A damping structure is provided at the bottom of the support shaft to decelerate the rotating propeller.

[0006] In some embodiments of the present invention, the damping structure includes a turntable mounted at the bottom of a support shaft, a long bar magnet being disposed at the bottom of the turntable, the length direction of the long bar magnet being along the radial direction of the turntable, and a coil being disposed on the outer side of the long bar magnet.

[0007] A fixing frame is fixed on the rotating arm, and a resistor block is fixed on the fixing frame. The resistor block is connected to both ends of the coil.

[0008] In some embodiments of the present invention, a magnetic field detector is fixed on the mounting bracket, and the magnetic field detector is located below the bar magnet.

[0009] In some embodiments of the present invention, a cylinder is fixed at the bottom of the rotating arm, and a pressing plate is provided at the movable end of the cylinder, which is used in conjunction with the turntable.

[0010] In some embodiments of the present invention, the clamping structure includes a plurality of clamping plates arranged in a ring around the axis of the support shaft, the clamping plates being connected to the support shaft by two inclined arms, and the two inclined arms on the clamping plates being parallel to each other.

[0011] The clamping plate is right-angled in shape. The horizontal part of the clamping plate is used to support the propeller, and the vertical part of the clamping plate is used to connect with the two inclined arms. A pressure plate is inserted through the support shaft, and the outer wall of the support shaft is provided with threads, and a lock nut is screwed on the threads.

[0012] In some embodiments of the present invention, a movable ring is slidably sleeved on the support shaft, and the movable ring is connected to each clamping plate by a connecting rod.

[0013] In some embodiments of the present invention, the detection device further includes an outer housing, which is located outside the turntable, the fixed arm, and the support shaft. The turntable is rotatably installed inside the outer housing. An opening is provided at the top of the outer housing, and a cover is provided on the opening. A main motor, an air bucket, and a pump body are provided on the outer housing. The output end of the main motor is connected to the turntable, the air bucket is in communication with the interior of the outer housing, and the output end of the pump body is in communication with the air bucket.

[0014] In some embodiments of the present invention, a buckle plate rolls on the turntable, and the rotating arm slides through the buckle plate along the radial direction of the propeller. The buckle plate is provided with locking bolts for locking the rotating arm.

[0015] The beneficial effects of this invention are as follows:

[0016] By utilizing centrifugal force to detect the propeller's center of gravity shift instead of gravity in traditional methods, a greater force can be applied to the propeller, making it easier to detect small imbalances and improving detection sensitivity. The damping structure allows for rapid propeller deceleration, bringing it to a stop quickly and avoiding the prolonged natural deceleration required in traditional methods, significantly shortening detection time. The structure is simple, and the detection process is streamlined; simply rotating the turntable and propeller drives the propeller in centrifugal motion, making operation more convenient and efficient. In summary, by introducing centrifugal force detection and a damping structure, the problems of low accuracy and long processing time in traditional static balance testing methods are solved, improving detection efficiency and reliability. Furthermore, this solution offers advantages such as ease of operation, high automation, and wide applicability, making it suitable for the high requirements of propeller static balance testing in modern shipbuilding industries. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Enlarged schematic diagram of the internal structure of the inner and outer casings;

[0020] Figure 3 yes Figure 2 A schematic diagram of the central support shaft and propeller;

[0021] Figure 4 yes Figure 3 A schematic diagram of the structure after the propeller has been disassembled;

[0022] Figure 5 yes Figure 4 Enlarged schematic diagram of the clamping structure. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] In the description of this invention, it should be noted that the orientations or positional relationships indicated by terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inner", and "outer" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. This embodiment is written in a progressive manner.

[0026] like Figures 1 to 5 As shown, a static balance testing device for a ship propeller according to the present invention includes a turntable 1, a fixed arm 2 and a support shaft 3. The axis of the turntable 1 is vertical, the fixed arm 2 is horizontally mounted on the turntable 1 and the length direction of the fixed arm 2 is along the radial direction of the turntable 1. The support shaft 3 is mounted on the end of the fixed arm 2 away from the turntable 1 and the axis of the support shaft 3 is vertical. The support shaft 3 rotates on the fixed arm 2 and is provided with a clamping structure for fixing the propeller 4.

[0027] When the turntable 1 rotates, the propeller 4 undergoes centrifugal motion. The bottom of the support shaft 3 is provided with a damping structure, which is used to decelerate the rotating propeller 4.

[0028] In the above embodiment, since the axis of the support shaft 3 is vertical, and the propeller 4 is mounted on the support shaft 3 through a clamping structure, the axis of the propeller 4 is also vertical. The rotating arm 2 is used to support the support shaft 3. When performing static balance testing on the propeller 4, the propeller 4 is rotated so that it can rotate freely. The turntable 1 is rotated so that the rotating arm 2, the support shaft 3, and the propeller 4 undergo centrifugal motion. Since the support shaft 3 can rotate on the rotating arm 2, the propeller 4 can rotate freely on the rotating arm 2. When the center of gravity of the propeller 4 structure is eccentric, due to the centrifugal force and the damping structure, the rotational speed of the propeller 4 gradually decreases. The propeller 4 is lowered until it stops, and the center of gravity of the propeller 4 will shift to the side away from the turntable 1. That is, the support shaft 3 will be located between the center of gravity of the turntable 1 and the center of gravity of the propeller 4. The propeller 4 is rotated again and made to rotate on its own axis. When the rotation of the propeller 4 stops again, the position of the propeller 4 on the rotating arm 2 is compared between the two tests. When the position of the propeller 4 is the same in the two tests, the center of gravity of the propeller 4 is deviated from the axis of the propeller 4, and the static balance test of the propeller 4 is unqualified. When the results of the two tests are inconsistent, the static balance test of the propeller 4 is qualified. This completes the static balance test of the propeller 4. Of course, multiple measurements can be performed to improve the test accuracy.

[0029] Based on the above embodiments, since the propeller 4 can rotate freely on the rotating arm 2 with the help of the support shaft 3, and gravity will not interfere with the rotation of the propeller 4, only by using a damping structure can the rotation speed of the propeller 4 be gradually reduced to prevent the propeller 4 from rotating continuously for a long time, thus shortening the detection time. Moreover, compared with gravity detection, the centrifugal force detection method can provide a larger and more accurate force to the propeller 4, thereby improving the detection accuracy.

[0030] By utilizing centrifugal force to detect the center of gravity shift of propeller 4 instead of gravity in traditional methods, a greater force can be applied to propeller 4, making it easier to detect small imbalances and improving detection sensitivity. The damping structure allows for rapid deceleration of the propeller, bringing it to a stop quickly and avoiding the prolonged natural deceleration required in traditional methods, significantly shortening the detection time. The structure is simple, and the detection process is streamlined; simply rotating the turntable 1 and propeller 4 is sufficient to drive the propeller 4 in centrifugal motion, making operation more convenient and efficient. In summary, by introducing centrifugal force detection and a damping structure, the problems of low detection accuracy and long processing time in traditional static balance detection methods are solved, improving detection efficiency and reliability. Furthermore, this solution offers advantages such as convenient operation, high automation, and wide applicability, making it suitable for the high requirements of propeller static balance detection in modern shipbuilding industries.

[0031] In some embodiments of the present invention, such as Figure 3 As shown, the damping structure includes a turntable 5 installed at the bottom of the support shaft 3, a long bar magnet 6 is provided at the bottom of the turntable 5, the length direction of the long bar magnet 6 is along the radial direction of the turntable 5, and a coil 7 is provided on the outer side of the long bar magnet 6.

[0032] A fixing frame 8 is fixed on the rotating arm 2, and a resistor block 9 is fixed on the fixing frame 8. The resistor block 9 is connected to both ends of the coil 7.

[0033] In the above embodiment, the clamping structure is located on the support shaft 3 on the upper side of the rotating arm 2, and the turntable 5 is located on the support shaft 3 on the lower side of the rotating arm 2. There is a magnetic field between the two poles of the bar magnet 6. When the propeller 4 rotates, it will drive the support shaft 3, the turntable 5 and the bar magnet 6 to rotate synchronously. The magnetic field around the coil 7 will change periodically. At this time, an induced current will be generated inside the coil 7. The induced current will be transmitted in the resistor block 9. The main function of the resistor block 9 is for circuit protection. Due to the back electromotive force generated by the current inside the coil 7, it will generate resistance to the rotation of the bar magnet 6 and the turntable 5. The higher the speed, the greater the resistance. Therefore, this structure can be used to generate resistance to the rotation of the propeller 4, so that the speed of the propeller 4 gradually decreases and stops.

[0034] Since the resistance generated by the back electromotive force is related to the rotational speed of propeller 4, the resistance of propeller 4 decreases when the rotational speed of propeller 4 decreases. Combined with the centrifugal force when propeller 4 is eccentric, the center of gravity of propeller 4 at its final position can be aligned with the support shaft 3 and the rotating arm 2 in a straight line. This method can locate the eccentric position of propeller 4, which facilitates subsequent repair work on propeller 4. This structural method can avoid the amplitude detection work of propeller 4 in the eccentric state in the traditional method, that is, it is not necessary to use the amplitude center line of propeller 4 when it swings left and right to locate the eccentric position of propeller 4.

[0035] It should be noted that since the slower the rotation speed of propeller 4, the less resistance it experiences, the phenomenon that the balance between gravity and friction causes the center of gravity of propeller 4 to deviate from the axis of propeller 4 when the friction force is constant in the traditional method can be avoided. This avoids the influence of friction force on the detection of propeller 4 and improves the detection accuracy.

[0036] In some embodiments of the present invention, such as Figure 4 As shown, a magnetic field detector 10 is fixed on the mounting bracket 8, and the magnetic field detector 10 is located below the long bar magnet 6.

[0037] In the above embodiment, by setting up a magnetic field detector 10, the direction of the magnetic field between the two poles of the bar magnet 6 can be easily detected, thereby detecting the position of the propeller 4. It is convenient to detect and compare the position of the propeller 4 each time it is stationary. The magnetic field detector 10 can use structures such as Hall effect sensors, magnetoresistors, magnetosensitive diodes, fluxgate sensors, and magnetic field analyzers to complete the detection of the magnetic field direction.

[0038] In some embodiments of the present invention, such as Figure 3 As shown, a cylinder 11 is fixed at the bottom of the rotating arm 2, and a pressing plate 12 is provided at the movable end of the cylinder 11. The pressing plate 12 is used in conjunction with the turntable 5.

[0039] In the above embodiment, when the propeller 4 stops rotating, the cylinder 11 extends and the extrusion plate 12 contacts the turntable 5. At this time, the extrusion plate 12 can lock the position of the turntable 5, thereby making the propeller 4 stationary. This allows the worker to mark the position of the propeller 4 at this time, which is convenient for subsequent maintenance work on the propeller 4.

[0040] In some embodiments of the present invention, such as Figure 5 As shown, the clamping structure includes a plurality of clamping plates 13 arranged in a ring around the axis of the support shaft 3. The clamping plates 13 are connected to the support shaft 3 by two inclined arms 14, and the two inclined arms 14 on the clamping plates 13 are parallel to each other.

[0041] The clamping plate 13 is right-angled. The horizontal part of the clamping plate 13 is used to support the propeller 4, and the vertical part of the clamping plate 13 is used to connect with the two inclined arms 14. A pressure plate 15 is inserted through the support shaft 3. The outer wall of the support shaft 3 is provided with threads, and a lock nut 16 is screwed on the threads.

[0042] In the above embodiment, the two inclined arms 14 on the clamping plate 13 form a parallelogram. One end of the inclined arm 14 is rotatably connected to the support shaft 3, and the other end of the inclined arm 14 is rotatably connected to the clamping plate 13. The inclined arm 14 is inclined upward. When the propeller 4 is mounted on the support shaft 3, the horizontal parts of the multiple clamping plates 13 are located at the bottom of the propeller 4 and lift the propeller 4. Due to the gravity of the propeller 4, the propeller 4 will press the clamping plate 13 downward. The two inclined arms 14 guide the clamping plate 13 and make the clamping plate 13 move outward. At this time, the vertical part of the clamping plate 13 will contact the inner wall of the propeller 4. Thus, the vertical parts of the multiple clamping plates 13 can be used to achieve the external support and fixation of the propeller 4. That is, at this time, the clamping plate 13 achieves the effect of lifting and external support and fixation of the propeller 4. The pressure plate 15 is pressed on the top of the propeller 4 and locked with the lock nut 16, thereby fixing the propeller 4.

[0043] Based on the above embodiments, in order to make it convenient for the multiple clamping plates 13 to be in a retracted state in their natural state, a spring can be added between each clamping plate 13 and the support shaft 3.

[0044] In some embodiments of the present invention, such as Figure 5 As shown, a movable ring 17 is slidably sleeved on the support shaft 3, and the movable ring 17 is connected to each clamping plate 13 by a connecting rod 18.

[0045] In the above embodiment, the connecting rod 18 is inclined upward, one end of the connecting rod 18 is rotatably connected to the moving ring 17, and the other end of the connecting rod 18 is rotatably connected to the clamping plate 13. When the clamping plate 13 moves, it will push the moving ring 17 to move through the connecting rod 18. Therefore, the moving ring 17 and multiple connecting rods 18 are used to achieve the effect of synchronous movement of multiple clamping plates 13, thereby enabling the vertical parts of multiple clamping plates 13 to synchronously support and fix the propeller 4, which facilitates the positioning of the axis of the propeller 4.

[0046] In some embodiments of the present invention, such as Figure 1 As shown, the detection device also includes an outer housing 19, which is located outside the turntable 1, the fixed arm 2, and the support shaft 3. The turntable 1 is rotatably installed inside the outer housing 19. An opening is provided at the top of the outer housing 19, and a cover 20 is installed on the opening. A main motor 21, an air bucket 22, and a pump body 23 are provided on the outer housing 19. The output end of the main motor 21 is connected to the turntable 1. The air bucket 22 is connected to the interior of the outer housing 19. The output end of the pump body 23 is connected to the air bucket 22.

[0047] In the above embodiment, the outer casing 19 can isolate the turntable 1 and the propeller 4 in motion on it, thereby avoiding the propeller 4 in rotation from causing harm to the workers. The opening and cover 20 on the outer casing 19 can facilitate the disassembly and assembly of the propeller 4. The main motor 21 can provide power to the turntable 1.

[0048] Since airflow is generated when the turntable 1 and the propeller 4 are centrifuged, in order to reduce the interference of airflow on the propeller 4 detection work, the air inside the outer casing 19 can be extracted by the pump body 23 and the air bucket 22, so that the propeller 4 can be detected in a vacuum environment, thereby improving the detection accuracy. When it is necessary to make the propeller 4 rotate, the pump body 23 can be reversed, so that the pump body 23 blows air to the propeller 4 through the air bucket 22. At this time, the airflow can make the propeller 4 rotate.

[0049] In some embodiments of the present invention, such as Figure 2 As shown, a buckle plate 24 rolls on the turntable 1, and the rotating arm 2 slides through the buckle plate 24 in the radial direction of the propeller 4. The buckle plate 24 is provided with a locking bolt 25 for locking the rotating arm 2.

[0050] In the above embodiment, by setting the buckle plate 24 and the locking bolt 25, the position of the rotating arm 2 on the turntable 1 can be adjusted, thereby adjusting the radius of the support shaft 3 and the propeller 4 during centrifugal movement, which facilitates the adjustment of centrifugal force.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A static balance testing device for ship propellers, characterized in that, It includes a turntable, a fixed arm, and a support shaft. The turntable axis is vertical, the fixed arm is horizontally mounted on the turntable and its length direction is along the radial direction of the turntable, the support shaft is mounted on the end of the fixed arm away from the turntable and its axis is vertical. The support shaft rotates on the fixed arm and is provided with a clamping structure for fixing the propeller. When the turntable rotates, the propeller undergoes centrifugal motion. A damping structure is provided at the bottom of the support shaft to decelerate the rotating propeller. The damping structure includes a turntable installed at the bottom of the support shaft, a long bar magnet is provided at the bottom of the turntable, the length of the long bar magnet is along the radial direction of the turntable, and a coil is provided on the outside of the long bar magnet; A fixing frame is fixed on the rotating arm, and a resistor block is fixed on the fixing frame. The resistor block is connected to both ends of the coil.

2. The static balance testing device for ship propellers according to claim 1, characterized in that, A magnetic field detector is fixed on the mounting bracket, and the magnetic field detector is located below the long bar magnet.

3. The static balance testing device for ship propellers according to claim 2, characterized in that, A cylinder is fixed at the bottom of the rotating arm, and a pressing plate is provided at the movable end of the cylinder. The pressing plate is used in conjunction with the turntable.

4. The static balance testing device for marine propellers according to claim 3, characterized in that, The clamping structure includes multiple clamping plates arranged in a ring around the axis of the support shaft. The clamping plates are connected to the support shaft by two inclined arms, and the two inclined arms on the clamping plates are parallel to each other. The clamping plate is right-angled in shape. The horizontal part of the clamping plate is used to support the propeller, and the vertical part of the clamping plate is used to connect with the two inclined arms. A pressure plate is inserted through the support shaft, and the outer wall of the support shaft is provided with threads, and a lock nut is screwed on the threads.

5. The static balance testing device for marine propellers according to claim 4, characterized in that, A movable ring is slidably sleeved on the support shaft, and the movable ring is connected to each clamping plate by a connecting rod.

6. The static balance testing device for ship propellers according to claim 5, characterized in that, The detection device also includes an outer housing, which is located outside the turntable, rotating arm and support shaft. The turntable is rotatably installed inside the outer housing. An opening is provided on the top of the outer housing, and a cover is installed on the opening. A main motor, an air bucket and a pump body are provided on the outer housing. The output end of the main motor is connected to the turntable. The air bucket is connected to the inside of the outer housing. The output end of the pump body is connected to the air bucket.

7. The static balance testing device for ship propellers according to claim 6, characterized in that, A buckle plate rolls on the turntable, and the rotating arm slides through the buckle plate along the radial direction of the propeller. The buckle plate is equipped with locking bolts for locking the rotating arm.

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