Thrust gap measuring device, thrust gap measuring method, and ship

Abstract

A marine double-reverse propeller assembly (100) comprises: an outer shaft (12) on which a front propeller (1) is mounted; an inner shaft (14) on which a rear propeller (2) is mounted; a double-reverse thrust bearing (40) that transmits the thrust of the front propeller to the inner shaft; and a double-reverse gear assembly (20) that causes the outer shaft and the inner shaft to rotate in opposite directions. The double-reverse gear assembly (20) has an inner shaft thrust bearing (50) that supports the thrust of the inner shaft and maintains its axial position. A thrust clearance measuring device (60) comprises: an inner shaft position sensor (62) that measures the inner shaft position (F1) during forward movement and the inner shaft position (R1) during reverse movement in the axial direction of the ship; and a thrust clearance calculation device (66) that calculates a first thrust clearance (C1) of the inner shaft thrust bearing.

Description

Technical Field

[0001] This invention relates to a thrust clearance measuring device, a thrust clearance measuring method, and a ship for a marine double-reverse propeller system. Background Technology

[0002] Marine dual-reversible propeller systems can be broadly categorized into two-shaft drive and single-shaft drive systems. The two-shaft drive system utilizes two concentric shafts to drive the front and rear propellers respectively. The single-shaft drive system incorporates a reversing mechanism between the front and rear propellers and uses a single shaft to drive both propellers.

[0003] Typically, the nose propeller is mounted at the rear end of the outer shaft, and the aft propeller is mounted at the rear end of the inner shaft. The device that causes the inner and outer shafts to rotate in opposite directions is called a "double reversible gear system." Whether it's a dual-shaft drive or a single-shaft drive system, the double reversible gear system is usually located within the hull.

[0004] The marine double-reverse propeller device is equipped with a double-reverse thrust bearing and an inner shaft thrust bearing.

[0005] A double-reverse thrust bearing is positioned between the outer and inner shafts to transmit the thrust from the outer shaft to the inner shaft. The inner shaft thrust bearing is mounted on a double-reverse gear assembly to support the thrust of the inner shaft and maintain its axial position.

[0006] The double-reverse thrust bearing and inner shaft thrust bearing involved have been disclosed, for example, in Patent Documents 1 and 2.

[0007] Prior art literature

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 5266542;

[0010] Patent document 2: Japanese Patent No. 6532927. Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] To maintain their respective functions, the double-reverse thrust bearing and the inner shaft thrust bearing need to be inspected and repaired regularly.

[0013] Previously, the inspection of double-reverse thrust bearings was carried out as follows.

[0014] (1) As a method to understand the condition of the double-reverse thrust bearing by performing non-open inspection on the marine double-reverse propeller device, the method is to capture foreign matter in the lubricating oil or understand its composition, and measure the thrust clearance and observe its changes over the years, and monitor abnormalities such as bearing damage or abnormal wear.

[0015] (2) The thrust clearance is determined by the following method: During dock construction, hydraulic jacks are used to push the shaft along the forward thrust direction and the backward thrust direction, and the distance between the inner shaft and the outer shaft (or the distance between the front and rear propellers) is measured and the difference is calculated.

[0016] However, the following problems were found in the aforementioned previous inspections.

[0017] (1) Even if an anomaly occurs during the operation of the ship, it cannot be detected by capturing foreign matter in the lubricating oil or by analyzing its composition, even if it is an accumulation of minor travel.

[0018] (2) During the dry dock construction every few years, if an abnormality in the thrust clearance is detected during the measurement in the dry dock, the open maintenance is carried out from that moment. The construction period is unexpectedly extended, resulting in significant adverse effects such as the need to reschedule the voyage.

[0019] (3) In particular, in the case of a double reverse propeller device for large ships, the weight of the shaft increases with the forward / backward movement of the shaft in the dry dock, and the hydraulic jacks used are also larger and heavier, resulting in very poor operability.

[0020] On the other hand, in the past, the thrust bearing (inner shaft thrust bearing) built into the double reverse gear device was subject to regular open maintenance.

[0021] However, the following problems exist in the above-mentioned inspection.

[0022] (1) In the case of small boats, the area equipped with double reverse gears is narrow, resulting in poor operability during open maintenance, which is the main reason for the increase in time and cost.

[0023] (2) In the case of large ships, the double reverse gear device is also large / heavy, and the operability during open maintenance is poor, which, like small ships, is the main reason for the increase in construction time and cost.

[0024] This invention is a pioneering invention designed to solve the aforementioned problems. Specifically, the object of this invention is to provide a thrust clearance measuring device, a thrust clearance measuring method, and a vessel capable of measuring thrust clearance during ship navigation without open maintenance of the marine double-reverse propeller system, as well as a vessel equipped with the thrust clearance measuring device.

[0025] Solution for solving the problem

[0026] According to the present invention, a thrust clearance measuring device is provided, which is a thrust clearance measuring device for a marine double counter-rotating propeller device in which the front propeller and the rear propeller are coaxially arranged and the front propeller and the rear propeller rotate in opposite directions.

[0027] The aforementioned marine dual counter-rotating propeller system includes:

[0028] The hollow outer shaft has the aforementioned front propeller mounted at its rear end and is supported in a manner that allows it to rotate about the shaft center.

[0029] The inner shaft has the aforementioned rear propeller mounted at its rear end and is supported in a manner that allows it to rotate about the aforementioned shaft center.

[0030] A dual-reverse thrust bearing that transmits the thrust acting on the aforementioned front propeller to the aforementioned inner shaft; and

[0031] A double reversible gear mechanism that causes the aforementioned outer shaft and the aforementioned inner shaft to rotate in opposite directions.

[0032] The aforementioned double reversible gear device has an inner shaft thrust bearing that supports the thrust of the aforementioned inner shaft and maintains its axial position.

[0033] The aforementioned thrust clearance measuring device has:

[0034] An inner shaft position sensor, during the operation of the ship, measures the inner shaft position F1 when it moves forward and the inner shaft position R1 when it moves backward in the axial direction; and

[0035] The thrust clearance calculation device calculates the first thrust clearance of the aforementioned inner shaft thrust bearing.

[0036] Furthermore, according to the present invention, a thrust clearance measurement method is provided, which uses the aforementioned thrust clearance measurement device.

[0037] During the ship's operation, the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward are measured.

[0038] The first thrust clearance of the aforementioned inner shaft thrust bearing is calculated based on the aforementioned inner shaft position F1 during forward movement and the aforementioned inner shaft position R1 during backward movement.

[0039] Invention Effects

[0040] According to the above-described configuration of the present invention, the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward are measured during the operation of the ship by means of an inner shaft position sensor. In addition, the thrust clearance calculation device calculates the first thrust clearance of the inner shaft thrust bearing based on the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward.

[0041] Therefore, it is possible to perform maintenance on the marine double counter-rotating propeller without opening the system, and to measure the thrust clearance while the ship is in motion. Attached Figure Description

[0042] Figure 1 This is a schematic top view of a marine double-reverse propeller device.

[0043] Figure 2 yes Figure 1 A side cross-sectional view of the double reversing gear device.

[0044] Figure 3 This is an explanatory diagram of the thrust clearance measurement method according to the present invention.

[0045] Figure 4 This is a schematic diagram showing the detection data from the inner shaft position sensor and the outer shaft position sensor. Detailed Implementation

[0046] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Furthermore, in the various figures, common parts are labeled with the same symbols, and repeated descriptions are omitted.

[0047] The ship according to the present invention is equipped with a thrust clearance measuring device 60 and a marine double reverse propeller device 100 according to the present invention.

[0048] Figure 1 This is a schematic top view of a marine dual counter-rotating propeller device 100.

[0049] In this figure, the marine double counter-rotating propeller device 100 is a device in which the front propeller 1 and the rear propeller 2 are arranged coaxially and the front propeller 1 and the rear propeller 2 rotate in opposite directions.

[0050] The marine double-reverse propeller assembly 100 includes an outer propeller shaft (hereinafter referred to as "outer shaft 12"), an inner propeller shaft (hereinafter referred to as "inner shaft 14"), a double-reverse gear assembly 20, a drive unit 30, and a double-reverse thrust bearing 40.

[0051] The outer shaft 12 is hollow, with a front propeller 1 installed at its rear end, and is supported in a manner that allows it to rotate around the shaft center.

[0052] The inner shaft 14 has a rear propeller 2 mounted at its rear end and is supported in a manner that allows it to rotate about the shaft center.

[0053] The double reversible gear mechanism 20 causes the outer shaft 12 and the inner shaft 14 to rotate in opposite directions.

[0054] The double reversible gear device 20 has an inner shaft thrust bearing 50 that supports the thrust of the inner shaft 14 and maintains its axial position.

[0055] The drive unit 30 is the rotation drive source for the outer shaft 12 and the inner shaft 14.

[0056] The dual reverse thrust bearing 40 transmits the thrust acting on the front propeller 1 to the inner shaft 14.

[0057] The outer shaft 12 is a hollow component that passes through the stern pipe 3, which is installed in the hull 90. A front bushing 5 and a rear bushing 6 are provided between the stern pipe 3 and the outer shaft 12, thereby supporting the outer shaft 12 in a rotatable manner by the hull 90. To prevent lubricating oil in the stern pipe 3 from leaking towards the engine room, a bow-side stern pipe sealing device 7 is provided on the bow-side end face of the stern pipe 3. To prevent lubricating oil in the stern pipe 3 from leaking towards the seawater, a stern-side stern pipe sealing device 8 is provided on the stern-side end face of the stern pipe 3.

[0058] The front propeller 1 has a hub 13 at its center, and the bow side end face of the hub 13 and the stern side end face of the outer shaft 12 are connected and fixed by bolts or other connection methods. An outer shaft sleeve coupling 16 is connected and fixed at the bow side end of the outer shaft 12.

[0059] At the bow side end of the outer shaft coupling 16, a hollow outer shaft intermediate shaft 17 is connected and fixed. The outer shaft intermediate shaft 17 has a configuration that can be divided into multiple (two or more) along the radial direction in order to enable maintenance of the accessories of the inner shaft 14 (such as the double reverse front seal device 37).

[0060] The inner shaft 14 is rotatably supported by the interior of the outer shaft 12. The rear propeller 2 has a hub 15 at its center, which is fitted into the rear end of the inner shaft 14 and fixed to the inner shaft 14 by a propeller nut 39.

[0061] In the marine double-reverse propeller assembly 100, a front radial bearing 35 and a rear radial bearing 36 are provided to rotatably support the inner shaft 14 using the outer shaft 12. Figure 1 In the example configuration, the front radial bearing 35 is disposed between the outer shaft coupling 16 and the inner shaft 14, and the rear radial bearing 36 is disposed between the hub of the front propeller 1 and the inner shaft 14. Furthermore, the positions of the front radial bearing 35 and the rear radial bearing 36 are not limited to the positions described above; for example, they could also be located between the front and rear ends of the outer shaft 12 and the inner shaft 14.

[0062] exist Figure 1In this configuration, a dual-reverse thrust bearing 40 is disposed inside the hub 13 of the front propeller 1. More specifically, an annular recess 13a is formed between the hub 13 and the outer shaft 12 of the front propeller 1, and the dual-reverse thrust bearing 40 is disposed in this annular recess 13a. The dual-reverse thrust bearing 40 may be, for example, a tilting pad type thrust bearing.

[0063] To lubricate the front radial bearing 35, the rear radial bearing 36, and the double-reversing thrust bearing 40, double-reversing lubricating oil (not shown) is supplied to the space between the outer shaft 12 and the hub 13 of the front propeller 1 and the inner shaft 14. To prevent leakage of the double-reversing lubricating oil, a double-reversing front seal 37 is provided on the bow side end face of the outer shaft coupling 16, and a double-reversing rear seal 38 is provided on the stern side end face of the hub 13 of the front propeller 1.

[0064] After lubricating the rear radial bearing 36, the double-reversing lubricating oil passes through the gap between the sealing gasket of the double-reversing rear sealing device 38 and the inner shaft 14, and through the oil passage 44 located inside the hub 15 of the rear propeller 2. Furthermore, the lubricating oil enters the hollow portion of the inner shaft 14 through the inside of the propeller cap 45 installed at the rear end of the hub 15, and returns to a lubricating oil reservoir (not shown) located in the engine room through a sealing device (not shown) located at the bow-side end of the shaft of the inner shaft output gear 29. Additionally, the opening at the front end of the shaft of the inner shaft output gear 29 is closed by a retaining flange 46.

[0065] exist Figure 1 In this configuration, the drive unit 30 consists of a first drive unit 31, a rotational drive source for the outer shaft 12, and a second drive unit 32, a rotational drive source for the inner shaft 14. The first drive unit 31 and the second drive unit 32 can be main engines such as gas turbine engines or diesel engines, or they can be electric motors. In the case of electric motors, for example, one or more gas turbine generators or diesel generators can be mounted in the engine compartment and used as power sources.

[0066] Figure 1 The dual reversible gear device 20 is configured to independently transmit the rotational driving force of the first drive device 31 and the second drive device 32 to the outer shaft 12 and the inner shaft 14, respectively. More specifically, the dual reversible gear device 20 has a housing 21, inside which are an outer shaft transmission mechanism 18A and an inner shaft transmission mechanism 18B.

[0067] The outer shaft transmission mechanism 18A has an outer shaft input gear 22, which is mounted on the same shaft as the output shaft 31a of the first drive unit 31 and is input with driving force from the first drive unit 31. The outer shaft transmission mechanism 18A also includes: a hollow outer shaft output gear 24, mounted on the same shaft as the outer shaft 12, which transmits rotational driving force to the outer shaft 12; and an outer shaft intermediate gear 23, which is positioned between the outer shaft input gear 22 and the outer shaft output gear 24. The output shaft 31a of the first drive unit 31 and the outer shaft input gear 22 are connected via a gear coupling 33a. Figure 1 In the middle, the outer shaft intermediate gear 23 is one, but it can also be multiple.

[0068] The inner shaft transmission mechanism 18B has an inner shaft input gear 27, which is mounted on the same shaft as the output shaft 32a of the second drive unit 32 and receives driving force from the second drive unit 32. The inner shaft transmission mechanism 18B also includes: an inner shaft output gear 29, which passes through the hollow portion of the outer shaft output gear 24 and is mounted on the same shaft as the inner shaft 14, transmitting rotational driving force to the inner shaft 14; and an inner shaft intermediate gear 28, which is positioned between the inner shaft input gear 27 and the inner shaft output gear 29. The output shaft 32a of the second drive unit 32 and the inner shaft input gear 27 are connected via a gear coupling 33b. Figure 1 In the inner shaft, there is one intermediate gear 28, but there can be multiple gears. The inner shaft output gear 29 and the inner shaft 14 are connected and fixed by an inner shaft sleeve coupling 26.

[0069] In the marine dual counter-rotating propeller assembly 100, the inner shaft thrust bearing 50 bears the thrust load from the inner shaft 14 (a combined load of the thrust load from only the inner shaft 14 and the thrust load from only the outer shaft 12) and transmits it to the hull 90. Figure 1 In the middle, the inner shaft thrust bearing 50 is disposed on the bow side of the housing 21 of the double reversing gear device 20. Therefore, the thrust load from the inner shaft 14 is supported by the hull 90 via the housing 21.

[0070] Furthermore, the location of the inner shaft thrust bearing 50 is not limited to the aforementioned position, as long as it can transmit the thrust load from the inner shaft 14 to the hull 90. Therefore, it can be located either inside or outside the hull 21, as long as it is closer to the bow side than the outer shaft output gear 24.

[0071] exist Figure 1 In the example configuration, both the outer shaft transmission mechanism 18A and the inner shaft transmission mechanism 18B are gear transmission mechanisms, but they can also be planetary gear devices.

[0072] Figure 2 yes Figure 1 A side cross-sectional view of the double reversing gear device 20.

[0073] In this figure, the inner shaft thrust bearing 50 includes a self-aligning radial bearing 52 and a self-aligning thrust bearing 53. Additionally, 54 and 55 are radial roller bearings, and 56 is a self-aligning radial bearing.

[0074] The hollow central shaft 25A of the outer shaft output gear 24 is supported by radial roller bearings 55 and self-aligning radial bearings 56 in a manner that allows it to rotate around its axis. Furthermore, the front end of the hollow central shaft 25A (shown as the left end in the figure) is connected to the outer shaft intermediate shaft 17 via a gear coupling 19. Additionally, in Figure 1 In this configuration, the outer shaft intermediate shaft 17 is connected to the outer shaft 12 via the outer shaft sleeve coupling 16. Furthermore, the connection between the outer shaft 12, the outer shaft sleeve coupling 16, and the outer shaft intermediate shaft 17 is secure and will not generate any axial clearance.

[0075] The central shaft 25B of the inner shaft output gear 29 is supported by an inner shaft thrust bearing 50 and a radial roller bearing 54 in a manner that allows it to rotate around its axis. Furthermore, in Figure 1 In this configuration, the front end of the central shaft 25B (shown as the left end in the figure) is connected to the inner shaft 14 via the inner shaft sleeve coupling 26. Furthermore, the connection provided by the inner shaft sleeve coupling 26 is secure and does not generate any axial clearance.

[0076] exist Figure 2 In this invention, the thrust clearance measuring device 60 includes an inner shaft position sensor 62, an outer shaft position sensor 64, and a thrust clearance calculation device 66.

[0077] The inner shaft position sensor 62 and the outer shaft position sensor 64 can be non-contact distance sensors fixed to a fixed part within the hull.

[0078] The distance sensor preferably has a measurement range of 10 mm to 100 mm with a detection accuracy of less than 10 μm. For example, laser displacement gauges, ultrasonic sensors, etc., can be used as distance sensors.

[0079] Alternatively, the thrust clearance calculation device 66 may be, for example, a computer (PC) having a storage device, a calculation device, an input device, and an output device.

[0080] The inner shaft position sensor 62 measures the inner shaft position F1 when the inner shaft 14 is moving forward and the inner shaft position R1 when it is moving backward in the axial direction during the operation of the ship.

[0081] The thrust clearance calculation device 66 calculates the first thrust clearance C1 of the inner shaft thrust bearing 50 based on the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward.

[0082] In addition, the outer shaft position sensor 64 measures the outer shaft position F2 when it moves forward and the outer shaft position R2 when it moves backward in the axial direction of the outer shaft 12 during the operation of the ship.

[0083] The thrust clearance calculation device 66 calculates the second thrust clearance C2 of the double reverse thrust bearing 40 based on the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward.

[0084] The first thrust clearance C1 is the overall axial clearance of the inner shaft thrust bearing 50, namely the self-aligning radial bearing 52 and the self-aligning thrust bearing 53. The first thrust clearance C1 is, for example, 0.2 to 0.3 mm under normal conditions.

[0085] The second thrust clearance C2 is the overall clearance in the axial direction of the double-reverse thrust bearing 40. The second thrust clearance C2 is, for example, 2.0 to 2.6 mm under normal conditions.

[0086] Figure 3 This is an explanatory diagram of the thrust clearance measurement method according to the present invention.

[0087] (Measurement of the first thrust gap C1)

[0088] As described above, the inner shaft 14 and the central shaft 25B are connected via the inner shaft sleeve coupling 26 in a manner that does not create axial clearance.

[0089] Therefore, during the operation of the ship, when moving forward, the thrust of the rear propeller 2 acts forward (to the right in the figure), and the central shaft 25B, together with the inner shaft 14 and the inner shaft sleeve coupling 26, is pushed forward in the axial direction, and the front clearance of the inner shaft thrust bearing 50 becomes 0.

[0090] Similarly, during ship operation, when reversing, the thrust of the rear propeller 2 acts backward (to the left in the figure), so the central shaft 25B, the inner shaft 14, and the inner shaft sleeve coupling 26 are pushed backward in the axial direction as a whole, and the rear clearance of the inner shaft thrust bearing 50 becomes 0.

[0091] The first thrust clearance C1 of the inner shaft thrust bearing 50 is the sum of the front clearance and the rear clearance.

[0092] Therefore, the difference in the forward and backward directions between the forward inner shaft position F1 measured when moving forward and the backward inner shaft position R1 measured when moving backward (Δ1=F1-R1) is equivalent to the first thrust clearance C1 of the inner shaft thrust bearing 50.

[0093] The inner shaft position sensor 62 is fixed to a fixed part inside the hull, such as the front end face of the detection center shaft 25B or the end face of the stop flange 46.

[0094] In this case, the reference position (measurement origin) of the inner shaft position sensor 62 is set, for example, at the front end face of the central shaft 25B. However, the fore-and-aft position of the front end face of the central shaft 25B varies depending on the ship's operating conditions, such as the temperature of the inner shaft 14 and the central shaft 25B, and the axial load.

[0095] Therefore, the measurement of the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward is preferably performed when the ship is in its operating state, such as when switching between forward and backward. This ensures that the ship's operating state is substantially the same, reducing measurement errors caused by the operating state.

[0096] (Measurement of the second thrust gap C2)

[0097] As described above, the outer shaft 12 and the outer shaft intermediate shaft 17 are connected via the outer shaft sleeve coupling 16 in a manner that does not create axial clearance.

[0098] Therefore, during the operation of the ship, when moving forward, the thrust of the front propeller 1 acts forward (to the right in the figure), thus the outer shaft 12 is pushed forward in the axial direction (to the right in the figure) and moves until the rear clearance of the double reverse thrust bearing 40 and the front clearance of the inner shaft thrust bearing 50 become 0.

[0099] Similarly, during ship operation, when reversing, the thrust of the front propeller 1 acts backward (to the left in the figure), thus the outer shaft 12 is pushed backward in the axial direction (to the left in the figure) and moves until the front clearance of the double reverse thrust bearing 40 and the rear clearance of the inner shaft thrust bearing 50 become 0.

[0100] The first thrust gap C1 and the second thrust gap C2 will change when moving forward and backward.

[0101] Therefore, the difference between the forward and backward directions of the forward outer shaft position F2 measured when moving forward and the backward outer shaft position R2 measured when moving backward is equivalent to the sum of the first thrust gap C1 and the second thrust gap C2.

[0102] Therefore, the value obtained by subtracting the value of the first thrust gap C1 (Δ1 = F1 - R1) from the difference between the outer shaft position F2 when moving forward and the outer shaft position R2 when moving backward (Δ2 = F2 - R2) is equivalent to the second thrust gap C2.

[0103] The outer shaft position sensor 64 is fixed to a fixed part inside the hull, for example, to detect the end face of the outer shaft intermediate shaft 17.

[0104] In this case, the reference position (measurement origin) of the outer shaft position sensor 64 is set, for example, at the rear end face of the outer shaft intermediate shaft 17. However, the fore-and-aft position of the rear end face of the outer shaft intermediate shaft 17 varies depending on the ship's operating conditions, such as the temperature of the outer shaft 12 and the axial load of the outer shaft intermediate shaft 17.

[0105] Therefore, the measurements of the outer shaft position F2 when moving forward and the outer shaft position R2 when moving backward are preferably performed during the ship's operation, such as when switching between forward and backward. Additionally, it is preferable to simultaneously measure the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward.

[0106] This allows the ships to operate in essentially the same way, reducing measurement errors caused by their operating conditions.

[0107] Figure 4 This is a schematic diagram showing the detection data of the inner shaft position sensor 62 and the outer shaft position sensor 64.

[0108] As shown in the figure, the detection data of the inner shaft position sensor 62 and the outer shaft position sensor 64 typically vary in a period corresponding to the rotational speed due to the rotation of the outer shaft 12 and the inner shaft 14. This variation can also occur, for example, due to axial offset of the measuring unit or vibration of the hull 90.

[0109] Therefore, for the measurements of the outer shaft position F2 when moving forward, the outer shaft position R2 when moving backward, the inner shaft position F1 when moving forward, and the inner shaft position R1 when moving backward, the average value can be used considering the above-mentioned variation range.

[0110] In addition, as mentioned above, the various measurements vary depending on the ship's operating state. Therefore, in what is considered to be the same operation of the ship, the outer shaft position F2 when moving forward, the outer shaft position R2 when moving backward, the inner shaft position F1 when moving forward, and the inner shaft position R1 when moving backward can be measured.

[0111] In addition, in order to understand and keep the ship's operating status consistent, it is preferable to measure and record the number of shaft rotations, rotation direction, shaft output (or shaft torque, shaft thrust), ship speed, handle position, hull vibration, etc.

[0112] According to the above-described embodiment of the present invention, the inner shaft position sensor 62 measures the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward during the operation of the ship. Furthermore, the thrust clearance calculation device 66 calculates the first thrust clearance C1 of the inner shaft thrust bearing 50 based on the inner shaft position F1 when moving forward and the inner shaft position R1 when moving backward.

[0113] Therefore, it is possible to measure the thrust clearance while the ship is sailing without opening the marine double counter-rotating propeller unit 100 for maintenance.

[0114] In addition, the following side effects can also be obtained.

[0115] (1) It can measure the thrust clearance during operation, thus enabling it to determine whether maintenance is needed or not before entering the dry dock.

[0116] (2) Measurements in dry docks require the use of hydraulic jacks to move along the axial direction, which requires skilled operation. However, since automatic measurement can be performed during operation, any person can perform the measurement.

[0117] (3) It can avoid regular open maintenance, thus reducing system downtime and costs.

[0118] (4) It can realize system automation for unmanned ships.

[0119] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0120] Symbol Explanation

[0121] C1 is the first thrust gap, and C2 is the second thrust gap.

[0122] Inner axis position when F1 moves forward, outer axis position when F2 moves forward.

[0123] The inner axis position when R1 moves backward, and the outer axis position when R2 moves backward.

[0124] 1. Front propeller, 2. Rear propeller, 3. Stern tube, 5. Forward side bushing

[0125] 6. Aft side bushing; 7. Bow side stern pipe sealing device; 8. Stern side stern pipe sealing device.

[0126] 12 Outer shaft (outer propeller shaft), 13 Hub, 13a Annular recess,

[0127] 14 Inner shaft (inner propeller shaft), 15 Shaft hub, 16 Outer shaft sleeve coupling.

[0128] 17. Outer shaft intermediate shaft; 18A. Outer shaft transmission mechanism; 18B. Inner shaft transmission mechanism.

[0129] 19 Gear coupling, 20 Double reversible gear assembly, 21 Housing,

[0130] 22 External shaft input gear, 23 External shaft intermediate gear, 24 External shaft output gear

[0131] 25A hollow central shaft, 25B central shaft, 26 inner shaft sleeve coupling.

[0132] 27 Inner shaft input gear, 28 Inner shaft intermediate gear, 29 Inner shaft output gear.

[0133] 30 Drive unit, 31 First drive unit, 31a Output shaft, 32 Second drive unit

[0134] 32a output shaft, 33a and 33b gear couplings, 35 front radial bearing.

[0135] 36 Rear radial bearing, 37 Double reverse front seal device.

[0136] 38. Double reverse rear seal device; 39. Propeller nut.

[0137] 40 Double reverse thrust bearing, 44 Oil passage, 45 Propeller cap.

[0138] 46. ​​Retaining flange; 50. Inner shaft thrust bearing; 52. Self-aligning radial bearing.

[0139] 53 Self-aligning thrust bearing; 54 and 55 Radial roller bearings.

[0140] 56 Self-aligning radial bearing; 60 Thrust clearance measuring device.

[0141] 62 Inner shaft position sensor, 64 Outer shaft position sensor, 66 Thrust clearance calculation device.

[0142] 90 hull, 100 marine double counter-rotating propeller system.

Claims

1. A thrust clearance measuring device for a marine double counter-rotating propeller assembly, wherein the front propeller and the rear propeller are coaxially arranged and the front propeller and the rear propeller rotate in opposite directions relative to each other. The marine dual counter-rotating propeller device includes: The hollow outer shaft has the front propeller mounted at its rear end and is supported in a manner that allows it to rotate about the shaft center. An inner shaft, on which the rear propeller is mounted at the rear end, is supported in a manner that allows it to rotate about the shaft center. A dual-reverse thrust bearing that transmits the thrust acting on the front propeller to the inner shaft; and A double reversible gear mechanism that causes the outer shaft and the inner shaft to rotate in opposite directions. The double reversible gear device has an inner shaft thrust bearing that supports the thrust of the inner shaft and maintains its axial position. The thrust clearance measuring device has the following features: An inner shaft position sensor, during the operation of a ship, measures the inner shaft position F1 when it moves forward and the inner shaft position R1 when it moves backward in the axial direction due to the thrust of the rear propeller. An outer shaft position sensor, during the operation of the ship, measures the outer shaft position F2 when it is forward and the outer shaft position R2 when it is backward, caused by the thrust of the front propeller in the axial direction; and The thrust clearance calculation device calculates the first thrust clearance of the inner shaft thrust bearing and the second thrust clearance of the double-reverse thrust bearing. The first thrust gap is calculated as the difference between the inner axis position F1 during forward movement and the inner axis position R1 during backward movement in the front-rear direction. The second thrust gap is calculated as the difference between the forward and backward directions of the outer shaft position F2 during the forward movement and the outer shaft position R2 during the backward movement, minus the first thrust gap.

2. The thrust clearance measuring device according to claim 1, wherein, The detection data of the inner axis position during forward movement and the inner axis position during backward movement change at a period corresponding to the rotation speed due to the rotation of the inner axis. The thrust clearance measuring device calculates the first thrust clearance and the second thrust clearance using the average value of the variation amplitude of the detection data.

3. The thrust clearance measuring device according to claim 1, wherein, The inner shaft position sensor or the outer shaft position sensor is a non-contact distance sensor fixed to a fixed part within the hull.

4. A method for measuring thrust clearance, Using the thrust clearance measuring device according to claim 1, During ship operation, the inner shaft position F1 during forward movement and the inner shaft position R1 during reverse movement, caused by the thrust of the rear propeller, and the outer shaft position F2 during forward movement and the outer shaft position R2 during reverse movement, caused by the thrust of the front propeller, are measured. The first thrust clearance of the inner shaft thrust bearing is calculated based on the difference between the forward and backward directions of the inner shaft position F1 during forward movement and the inner shaft position R1 during backward movement. The second thrust clearance of the dual reversing thrust bearing is calculated as the difference between the forward and backward directions of the outer shaft position F2 during the forward movement and the outer shaft position R2 during the backward movement, minus the first thrust clearance.

5. The thrust clearance measurement method according to claim 4, wherein, When switching the ship's forward and reverse directions, the outer shaft position F2 during forward movement and the outer shaft position R2 during reverse movement are measured, and simultaneously the inner shaft position F1 during forward movement and the inner shaft position R1 during reverse movement are measured.

6. A ship having the thrust clearance measuring device according to claim 1.

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