JPS58102839A - Vibrating force eliminating device for shaft direct coupling type propeller - Google Patents

Abstract

PURPOSE:To prevent the vibration of a hull effectively by a method wherein a balancer consisting of a pair of rotating bodies, having eccentric masses and driven to rotate into opposed directions each other by a propeller driving shaft at a predetermined speed ratio, is provided near a stern tube bearing. CONSTITUTION:The vibrating force eliminating device is consisting of the balancer 10, having the eccentric masses 8, 8' and consisting of a pair of gears 9, 9' being rotated into opposed directions each other, a power transmitting gear 11 driving the gear 9 and a driving gear 12 or the like attached to a propeller shaft 3 for driving the power transmitting gear 11. A pair of gears 9, 9' and the eccentric masses 8, 8' are arranged in symmetry with respect to the centerline (c) of the hull.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a vibration damper for suppressing hull vibration generated by a propeller for propulsion of a ship, in particular, a vibration damper having a main shaft-driven balancer provided near the stern tube bearing. The present invention also relates to a shaft-directly coupled propeller vibration force damper that can effectively suppress propeller vibration force and reduce hull vibration.

The excitation force of the propeller is mainly caused by the uneven distribution of water flow under the water surface where the propeller operates. In other words, the propeller operates in the wake that tracks the ship's hull and generates propulsive force, but because the distribution of the wake is not uniform, the propeller's propeller blades and each position in the blade length direction generate propulsive force. The inflow angle is different. Therefore, the propulsive force and water flow torque generated by each blade fluctuate with each rotation, and the former generates an excitation force in the propeller axis direction and causes longitudinal vibration of the ship, while the latter acts in a plane perpendicular to the propeller axis. This causes torque fluctuations that cause lateral vibrations of the hull.

In order to reduce the excitation force of the propeller, research has been done to make the water flow distribution as uniform as possible by changing the shape of the propeller blades or changing the shape of the stern, but all of these measures deteriorate propulsion efficiency. Contains shortcomings.

Additionally, an electric balancer is installed at the stern to reduce vertical vibration of the hull. This type of balancer is driven by a synchronous motor and a synchronous generator in order to accurately follow the rotational speed of the propeller.
It is expected that it will be difficult to accurately match the phase of the balancer with the phase of the excitation force of the propeller, which may cause a shift in the electrical load angle. Furthermore, if it is desired to suppress several types of vibration orders, it is necessary to install several sets of balancers, but electric balancers have a complex structure and are expected to be difficult to put into practical use.

The present invention solves the above-mentioned problem, can accurately match the phase with the propeller motive force, does not cause a phase shift during operation, and can be easily connected to the source of the motive force. A balancer made for the purpose of providing a shaft-directly connected propeller starting force dampener that can be placed in close proximity, and consisting of a pair of rotating bodies that have eccentric masses and rotate in opposite directions.
A required number of F are arranged in the vicinity of the stern tube shaft and receiver, and the balancers are configured to be rotationally driven by the propeller drive shaft via a speed increasing mechanism having a speed ratio determined for each balancer. That is.

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 1 to 5, code (1) is the hull, and (2)
is a propeller, (3) is a propeller shaft, (4) is a stern tube bearing, and (5) is a stern bulkhead, and the vibration damper (6) of the present invention, as shown in FIGS. 1 and 2, It is installed on the inner bottom plate (7) near the stern tube bearing. The vibration dampers (6) have an eccentric mass +sz tsi and are directed in mutually opposite directions (arrows α, b
), a pair of gears (91f91) rotate, and a power transmission gear (1υ) that drives the gear (9).
In order to drive the power transmission gear aυ, it consists of a drive gear (121, etc.) attached to the propeller shaft (3), and the pair of gears (97 (9) and eccentric ii (81ts'r) arranged symmetrically.

Further, a base plate Oa that rotatably supports the gear (91 (9'5) rotating shaft (13) a4 is provided, and the base of the base plate Q4) is fixed to the inner bottom plate (7).

Note that a sprocket and chain may be used to transmit power from the drive gear (12+) to the gear (9) via the power transmission gear 0υ.Also, the arrangement of the eccentric mass (8) (81) described above is This is an arrangement for damping vibration force, but in particular when damping vibration excitation force in the horizontal direction, as shown in Figure 5, one of the eccentric masses (8) (8) should be moved from the left-right symmetry described above. Place them 180 degrees apart.

Number of teeth of drive gear 0 and balancer gear (9) (95
The ratio of the number of teeth, that is, the diameter ratio, is an integral multiple of the number of propeller blades. For example, in order to suppress the third-order excitation force of a three-blade propeller, the diameter d of the drive gear 03 should be set to the balancer gear (
91 (3 times the diameter l of si, and 6 times to suppress the 6th order vibrational force.

In addition, when canceling both the 3rd and 6th order vibrational forces, 3
The next balancer a1 and the sixth balancer (not shown) are arranged parallel to each other.

Note that the eccentric mass (81tsi) is the total value FB generated by the rotation speed determined by the diameter ratio of the propeller (2
) is selected to be approximately equal to the excitation force Fp generated at ).

The power transmission gear (1υ) is supported so as to be movable in the axial direction (arrow e) as shown in Fig. 4, and in order to match the phase of the propeller blades with the phase of the balancer, After disengaging and matching the phases, the two are re-engaged to maintain the matched phases.

Next, the operation of this device and the procedure for adjusting the phase will be explained using a three-blade propeller that rotates in a right-handed screw direction and moves forward.

To match the phase of the balancer and propeller, first use the method below to get a rough idea, and then actually improve the accuracy through testing or driving. Move the power transmission gear 0υ to the position shown by the two-dot chain line and connect the propeller shaft (3) and gear (9).
) and (9) so that they can rotate freely relative to each other, and 3
One of the blades is placed horizontally facing the starboard side, while the eccentric mass tar (st
set to the lowest position, then re-engage the transmission gear 0υ. Since the action of the water flow acting on the propeller is complex, readjustment is carried out through testing or operation to match the correct phase, and the matched phase is fixedly maintained using the transmission gear aυ. When the blade rotates in the f direction with the phase adjusted, when the excitation force FP acts on the propeller, eccentricity ii (81 (85 is centrifugal force FB (FP in FB)) is generated and the excitation force FP is cancelled. (See Figure 1). Unlike conventional electric balancers, there is no risk of the motor's load angle shifting during load operation, and the matched phases are mechanically fixed, making it easy and accurate. It is possible to maintain the phase of the propeller shaft and obtain an appropriate vibration damping effect.The diameter l of the balancer gear (9) (95) is % of the diameter of the drive gear, so during one revolution of the propeller shaft, Balancer gear (9) (95 rotates 3 times and can dampen the 3rd order vibration force of the propeller. Furthermore, the balancer gear (9) is placed near the stern tube bearing (4) close to the vibration source. Therefore, unlike conventional vibration dampers, it does not indirectly suppress the vibrations generated in the hull, but rather suppresses the vibrational force itself, which has a large vibration damping effect.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

Since the shaft-directly coupled propeller vibration force damper of the present invention has the above-described configuration, it exhibits the following excellent effects.

(1) Since the vibration damper is placed near the stern tube bearing, the propeller vibration force can be directly damped, and hull vibration can be effectively prevented.

(11) Since the damper is rotationally driven by the propeller drive shaft at a predetermined speed ratio, no phase shift occurs during operation.

(iii) By removably providing the gear that transmits the rotational force of the propeller drive shaft, it is possible to accurately and easily match the phase of the excitation force of the propeller.

Ov) For the same reason as the second term, it is possible to cancel the vibrational force of a desired order.

(V) By arranging multiple pairs of balancers that match the orders of multiple excitation forces to be damped in parallel, a desired order of excitation force can be achieved. All vibrations can be extinguished.

(By arranging the vD-set of balancers symmetrically with respect to the hull center line or vertically symmetrically in the vertical direction, the vibration excitation force in the vertical direction or the vibration excitation force in the lateral direction can be eliminated. be able to.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the installation position of a shaft-directly coupled propeller excitation force vibration absorber according to an embodiment of the present invention, Fig. 2 is a plan view cut from the ■-■ direction in Fig. 1, and Fig. 3 1 is a front view showing the schematic structure of the embodiment shown in FIG. 1, FIG. 4 is a side view taken from the rV-IV force direction in FIG. 3, and FIG. 5 is an explanatory view showing another arrangement of the balancer. In the figure, (2) is the propeller, (3) is the propeller m, (4)
is the stern tube bearing, (6) is the vibration damper, (8) (8') is the eccentric mass, (9) (9) is the gear, 00) is the balancer ~, a
υ is the power transmission gear, FP is the propeller excitation force, and FB is the centrifugal force generated by the vibration damper. Figure 4 12 919'1 Figure 5

Claims (1)

[Claims] 1) A required number of balancers consisting of a pair of rotating bodies having eccentric mass and rotating in opposite directions are arranged near the stern tube bearing, and each balancer is provided with a speed increasing mechanism having a predetermined speed ratio for each balancer. A shaft-directly connected propeller excitation force damper, characterized in that it is configured to be rotationally driven by a propeller drive shaft through the propeller drive shaft.