JPH0893853A - Dynamic vibration reducer for rotary shaft system torsional vibration - Google Patents

Abstract

PURPOSE: To enable an engine to be used at the rotation speed which is considered in a dangerous rotation region by constituting a flywheel or chaining wheel in a diesel engine as a dynamic vibration reducer for torsional vibration control. CONSTITUTION: A flywheel is divided into an inner ring 21 and an outer ring 22 combined with each other, and the inner ring 21 and the outer ring 22 are relatively movably connected to each other by the even number of recessed/ projected fitting parts 23a, 23b, 24a, 24b having different radiuses. Oil pressure cylinders 25a, 25b are provided between opposing and projecting side walls of the inner and outer rings 21, 22, and springs 27a, 27b are juxtaposed to respective oil pressure cylinders 25a, 25b. Further, an oil pressure cylinder 26b with a spring 28b and an oil cylinder 26a with a spring 28a are respectively equipped axially symmetrically to the oil pressure cylinder 25a with spring 27b and the oil pressure cylinder 25b with spring 27b. The mutually reversing oil pressure cylinders 25a and 25b, and 26a and 26b are connected to each other by means of oil pressure pipings 29a, 29b in which throttle valves 30a, 30b and normally closed solenoid valves 31a, 31b are interposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine and a dynamic vibration absorber for torsional vibration such as a shaft system using the diesel engine.

[0002]

2. Description of the Related Art A conventional dynamic vibration absorber for torsional vibration will be described with reference to FIGS. FIG. 6 is a plan view of a conventional example, and FIG.
FIG. 7 is a sectional view taken along line VII-VII of FIG. 6. If there are many identical objects in the figure, they are indicated by suffix n. A conventional torsional vibration absorber has an inner ring 1 and an outer ring 2 composed of a tightening ring 2a provided on the circumferential side, side plates 7a and 7b, an intermediate piece 4n, and fixing bolts 8n and 9n for tightening these. Then, the inner ring 1 and the outer ring 2 (2a, 7a, 7
b, 4n, 8n, 9n) are connected by a leaf spring 5n incorporated in a spring pack 6n made of an intermediate piece 4n, and further, side plates 7a, 7b of the outer ring 2.
The joint between the inner ring 1 and the inner ring 1 has bearing bushes 3a and 3b.

The inner ring 1 is constructed so as to be attached to the end of the target shaft, has a lubricating oil sump 11 in the center, and a lubricating oil supply port 10 for supplying oil from the outside is provided in the center. . Further, a lubricating oil hole 12n for supplying oil to the spring pack 6n is opened from the lubricating oil sump 11,
Further, an oil drain plug 13 is provided on one side plate 7b of each spring pack 6n.

The rigidity of the leaf spring 5n is preset so as to match the torsional natural vibration of the object, and the generated torsional vibration of the object is transmitted to the outer ring 2 via the inner ring 1 and the outer ring 2 It vibrates with a relative difference with the inner ring 1 to generate a damping force. The vibration damping of the outer ring 2 at this time is due to the friction between the leaf spring 5n and the intermediate piece 4n and the lubricating oil discharge plug 13n.
It is carried out by the adjustment of.

[0005]

Since the torsional resonance frequency of the shaft system composed of the crankshaft, propeller shaft and intermediate shaft of a marine diesel engine exists in the engine operating speed range, if they resonate. In this case, excessive torsional stress is generated and the shaft system is damaged. For this reason, at present, the resonance speed range is not used as a dangerous speed range, but since low-speed diesel is advanced in recent years to achieve low fuel consumption, the usable speed range is very narrow. It is desired that it can be used in the resonance rotation range.

Therefore, a torsional vibration absorber is required in order to make it usable in the torsional resonance region of the shaft system, but a conventional torsional vibration absorber requires addition of a large device, which is lightweight and compact. It is not suitable for, and becomes more expensive. In addition, there is a defect that these can be attached only to the tip of the shaft system.

An object of the present invention is to provide a dynamic vibration absorber for torsional vibration, which can be lightened and downsized, does not require a special mounting position, and can be used in an engine even in a dangerous rotation range where resonance occurs.

[0008]

A dynamic vibration reducer for torsional vibration of a rotary shaft system according to the present invention is a flywheel or a tuning wheel mounted on a crankshaft of a diesel engine for driving a propulsion device such as a ship. Alternatively, a pair of spring attenuators in which the tuning wheel is separated into an inner ring and an outer ring, and two sets of hydraulic cylinders and springs are circumferentially incorporated in opposite directions in the inter-combination portion of the inner ring and the outer ring. Are installed in point symmetry with respect to the axis, and the hydraulic cylinders of the pair of spring dampers are further connected via a throttle valve and a solenoid valve to control the opening / closing of the solenoid valve from the outside. It is characterized by having a mechanism.

[0009]

FIG. 8 is a diagram showing the relationship between the rotational speed of the crankshaft system of an engine having N cylinders and the torsional vibration stress with and without the dynamic vibration absorber. In the figure, the vertical axis represents the torsional vibration stress σkgf / mm ² , and the horizontal axis represents the number of revolutions per minute. In the figure, the alternate long and short dash line is a stress curve when a dynamic vibration absorber is not used, and it is possible to generate a large torsional stress by resonating at the engine rotation speed r _i at the natural frequency ω _i = r _i × N of the shaft system. It is shown.

[0010] The dashed line shafting natural frequency omega _i = r _i × N to the conventionally stress lines when fitted with conventional dynamic vibration absorber that is tuned dynamic vibration absorber effect of the engine rotational speed r _i of It shows that the torsional vibration stress is reduced. The reduction effect can be optimally adjusted by adjusting the ratio of the effective moment of inertia of the shaft system to the inertia moment of the dynamic vibration absorber and the damping of the dynamic vibration absorber, but the torsional vibration of the shaft system and the torsional vibration of the dynamic vibration absorber are Coupled, engine speed r as shown
_Since resonance peaks of torsional vibration stress are generated on the low speed side r _s and the high speed side r _e of _i respectively, the torsional vibration stress (shown by a broken line) in the rotational speed range of r _s or less and r _e or more is indicated by the dynamic vibration reducer. Is greater than the stress when not used (indicates the alternate long and short dash line and partially overlaps the solid line).

The solid line is a vibration stress curve when the dynamic vibration absorber of the present invention in which the natural frequency is tuned to the natural frequency ω _i of the shaft system is used, and the engine rotational speed r is monitored and the solenoid valve is always operated. Is closed, the inner and outer rings are fixed, the dynamic vibration absorber is inactive, and the dynamic vibration absorber has no characteristics. R _s <r <r
_In the case of _e , the solenoid valve is controlled from the outside to open the inner ring and the outer ring to release the fixation, so that the dynamic vibration absorber is in the operating state and the characteristics shown by the broken line are obtained, and the torsional vibration stress is reduced.

The damping of the dynamic vibration absorber, which affects the damping effect, is adjusted by the throttle valve. With the above operation, the dynamic vibration reducer of the present invention can obtain the best reduction effect as shown by the solid line in FIG. 8 and also the effect as the turning gear and the flywheel.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIGS. 1 is a front view of a first embodiment according to the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a line III-II of FIG.
1 sectional view, FIG. 4 is a sectional view taken along line IV-IV of FIG. 1, FIG. 5 is a schematic diagram applied to a ship, and FIG. 8 is an effect line of a dynamic vibration absorber for torsional vibration of a conventional example and a first example according to the present invention. It is a figure.

The main body of the dynamic vibration reducer is composed of an inner ring 21 and an outer ring 22 in which flywheels are interlocked with each other. , 24b are joined together to form a mechanism capable of relatively moving in the circumferential direction by the concave-convex fitting portion, and a large gap is provided in the circumferential direction.

The inner ring 21 is joined to the outer ring 22 at the concave and convex fitting portions 24a and 24b of the large outer diameter, and the portion protruding into the outer ring 22 at the concave and convex fitting portions 23a and 23b of the small outer diameter portion. It is joined. Hydraulic cylinders 25a, 25b are provided in opposite directions in the circumferential direction between the side walls of one protrusion of the inner ring 21 and the side walls of the outer ring 22 which are opposed to each other, and the hydraulic cylinders 25a, 25b are provided. Springs 27a and 27b are provided in parallel with and fixed to one side of the hydraulic cylinder while supporting the other side.

A hydraulic cylinder 26b and a spring 28b are axially symmetric to the hydraulic cylinder 25a and a spring 27a, and a hydraulic cylinder 26a and a spring 2 are symmetrical to the hydraulic cylinder 25b and the spring 27b.
8a is provided. Hydraulic cylinders 2 facing each other
5a and 25b, 26a and 26b are throttle valves 30 respectively.
a, 30b and normally closed solenoid valves 31a, 31b and hydraulic pipes 29a, 29b are connected to each other.

Therefore, a pair of hydraulic cylinders 25a, 25b
And the oil inside 26a and 26b is the solenoid valves 31a and 31b.
Open the hydraulic lines 29a, 29b, throttle valves 30a, 30
b and the solenoid valves 31a and 31b are used to move back and forth. Supply of voltage to the solenoid valves 31a and 31b is performed via the slip ring 35, the brush 36, and the control circuit 37 outside the shaft system in FIG. A rotation detector 38 is connected to the control circuit 37.

The operation of the first embodiment will be described. The control circuit 37 sets the rotational speed r obtained from the rotation detector 38 in advance has been rpm r _s, as compared to r _e, r _s ≦ r ≦ r brushes 36 in the case of _e, the solenoid valve through a slip ring 35 A voltage is supplied to 31a and 31b. Then the solenoid valve 31
a and 31b are opened, and the pair of hydraulic cylinders 25a and 25b and 26a and 26b are connected to each other by hydraulic pipes 29a and 29b through throttle valves 30a and 30b and solenoid valves 31a and 31b.

If r <r _s or r> r _e , the control circuit 37
Does not supply voltage to the solenoid valve. At this time, the solenoid valve is closed and the hydraulic cylinders 25a and 25b and 26a and 26b are closed.
Are not communicated with each other, and the inner ring 21 and the outer ring 22 are integrated so that they do not vibrate.

The adjustment of the vibration damping of the dynamic vibration absorber, which affects the vibration damping effect of the vibration, is performed by the pair of hydraulic cylinders 25a and 2a, respectively.
5b and throttle valves 30a and 30b for adjusting the oil flow rate between 26a and 26b.

[0021]

EFFECTS OF THE INVENTION The flywheel (turning gear) or tuning wheel currently associated with a diesel engine is used as a dynamic vibration absorber for torsional vibration control, so that the engine can be used even at a rotation speed that is in a dangerous rotation range. ． Further, the above-mentioned dynamic vibration absorber has a structure in which it operates only in a required rotational speed range (torsional resonance range), so that the best vibration damping effect can be obtained, and at the same time, the effect as a current flywheel or tuning wheel can be achieved. it can.

[Brief description of drawings]

FIG. 1 is a front view of a dynamic vibration absorber for torsional vibration according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a schematic diagram when the dynamic vibration reducer of the present invention is applied to an actual ship.

FIG. 6 is a front view showing a conventional dynamic vibration absorber for torsional vibration.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is an effect diagram of a conventional dynamic vibration absorber for torsional vibration and the present invention.

[Explanation of symbols]

1 ... Inner ring, 2 ... Outer ring, 2a ... Tightening ring, 3a, 3b
... Bearing bush, 4n ... Intermediate piece, 5n ... Leaf spring,
6n ... Spring pack, 7a, 7b ... Side plate, 8n ... Fixing bolt, 9n ... Fixing bolt, 10 ... Lubricating oil supply port, 1
1 ... Lubricating oil sump, 12n ... Lubricating oil hole, 13n ... Lubricating oil discharge plug, 21 ... Inner ring, 22 ... Outer ring, 23a, 23b ...
Small-diameter concave-convex fitting portion, 24a, 24b ... Large-diameter concave-convex fitting portion,
25a, 25b ... Hydraulic cylinders (1 pair), 26a, 26
b ... Hydraulic cylinder (1 pair), 27a, 27b, 28a,
28b ... Spring, 29a, 29b ... Hydraulic piping, 30a, 3
0b ... Throttle valve, 31a, 31b ... Electromagnetic valve, 32 ... Inner ring shaft mounting hole, 33 ... Outer ring turning gear portion, 34a, 3
4b ... Solenoid valve power supply cable, 35 ... Slip ring, 36 ... Brush, 37 ... Solenoid valve control circuit, 3
8 ... Rotation detector.

Claims (1)

[Claims] 1. A flywheel or a tuning wheel mounted on a crankshaft of a diesel engine for driving a propulsion device such as a ship, wherein the flywheel or the tuning wheel is separated into an inner ring and an outer ring,
Several sets of spring attenuators are installed symmetrically with respect to the shaft core, one pair of spring attenuators in which two sets of hydraulic cylinders and springs are installed in opposite directions in the circumferential direction between the combination of the inner ring and the outer ring. A rotary shaft further comprising a mechanism for connecting the hydraulic cylinders of the pair of spring dampers via a throttle valve and a solenoid valve, and externally controlling opening / closing of the solenoid valve. Dynamic vibration absorber for system torsional vibration.