JPS6034550A - Multicylinder internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine, in which fixed counters are installed at the front and rear ends of the crankshaft in order to balance the moment generated by inertial force. Weights are attached. The invention may be particularly, but not exclusively, applied to propulsion engines for motor ships.

The above-mentioned counterweights rotate together with the crankshaft, and the purpose of providing them is to eliminate the first-order free movement generated from the engine's unbalanced rotating mass and reciprocating mass, which changes periodically at a period equal to the engine speed. This is to reduce the moment. It is possible to use two counterweights of the same size and attach them to the front and rear ends of the crankshaft, respectively, so that their centers of gravity are at the same distance from the axis of the crankshaft and are offset by 180° from each other. This is the normal method. In this way, the two counterweights generate two synchronized centrifugal forces in opposite directions, thereby generating a moment vector that has a constant length (constant thickness) and whose direction changes continuously. The moment due to the inertial force of the rotating mass of the engine (lance) also has a constant thickness and a direction that changes continuously, but the inertial force of the reciprocating mass works within the plane (including the cylinder axis), but
The magnitude generates a moment that varies periodically during each revolution of the crankshaft.

By appropriately selecting the counterweight related factors (which determine the balancing moment generated by the centrifugal force or inertial force of the counterweight), it is possible to work in the vertical and horizontal planes. It is possible to respectively reduce the maximum value of the total free moments. Depending on the conditions that determine the vibration mode of the structure, especially the hull of the ship in which the engine is installed, it is possible to achieve a perfect balance within one of the above two planes (in this case, the vibration acting on the other plane). (the maximum moment is equal to the maximum value of the moment due to the inertia of the reciprocating mass), or an intermediate solution in which a periodically varying moment with a lower maximum value occurs in each of the above two sides. A choice may be made to do so.

The purpose of the present invention is to easily adjust the degree of balance that was initially adjusted, both after the completion of the engine and after installation.
In particular, the object is to provide a means that allows the engine to be changed without requiring major modifications to the engine itself.

The engine according to the invention is of the type mentioned at the outset, but is characterized in that each fixed counterweight is fitted with two mutually identical additional (adjustable) counterweights, which counterweights are connected to the surroundings. each of them to a fixed counterweight,
The mounting has means for positioning at selected angular positions with respect to a straight line connecting the center of the crankshaft and the center of gravity of the fixed counterweight.

The present invention will now be described with reference to two embodiments shown in the drawings. Figures 1 and 2 show an ocean-going vessel 1, such as a tanker or a cargo ship, which has a propulsion engine ( internal combustion engine) 2. The engine 2 may be a four-cylinder, two-stroke diesel engine directly connected to a propeller 3 of the ship, as shown in FIG. FIG. 2 further shows two sets of counterweights 4, 5, which are attached to the front and rear ends of the crankshaft of the engine 2, respectively. When the crankshaft rotates, the two sets of counterweights 4, 5 generate two opposite inertial forces or centrifugal forces 6, 7, which cause
A moment vector is generated that rotates at the same rotational speed (Crpm) as the crankshaft.

FIG. 2 further shows a set of counterweights (8'e) placed immediately after the rearmost cylinder of the engine 2, and these 80 sets of counterweights are always in the same plane, horizontal plane as shown in FIG. Generates an inertial force 9 that acts on .

A set of counterweights 4 at the front end of the engine 2 has - as shown in FIGS. 3 and 4 - a disc 10;
Disk 10 is secured to a flange 11 at the front end of engine crankshaft 12 by a number of bolts (not shown). The disk 10 is integral with the counterweight 13, and the counterweight 13 is symmetrical with respect to the diameter 14 of the disk 10, so that the counterweight 1
30 The center of gravity is placed on the above diameter. An annular groove 15 concentric with the crankshaft 12 is formed on the front surface of the disc 10, and a number of holes 16 parallel to the axis of the crankshaft are provided in the groove 150, and each hole 16 has an internal thread. are cut, so that two identical bolts or screws 17 can be received for fixing the counterweight 18 to the disc 10, the angular position of which can be adjusted.

As shown in FIG. 3, each of the adjustable counterweights 18 is attached to the p-disk 1o by three bolts 17, and the bolt receiving holes 16 are arranged in two groups symmetrical with respect to the diameter 14. The group has nine equiangularly spaced threaded holes, thus providing that in each case the adjustable counterweight is to be placed symmetrically with respect to the diameter line 14 (adjustable counterweight). It is possible to attach 180 pairs to the disk 10 in seven different angular positions. With this arrangement, the above-mentioned centrifugal force 6 can be divided into the maximum value when the counterweight 18 is placed at the end position shown in FIGS. It is possible to change stepwise IC between the opposite end position [ft] and the minimum value of the cutoff.

The counterweight set 5 at the rear end of the engine 2 is basically designed in the same way as shown in FIGS. The wheel support is attached to the rear end of the crankshaft 12, and gear teeth 21 are formed around the wheel support, and as is well known, the teeth 21 are used to slowly rotate the crankshaft. can be engaged with a pinion gear on a rotary motor (not shown). An annular groove 15 similar to the groove 15 in the disc 10 is formed in the rearward facing surface of the wheel, and a total of 18 threaded holes 16 are formed in the bottom of the groove 15. are arranged in the same pattern as the screw holes of the symmetrical fixed counterweight 190, ie, symmetrically about a diameter of 4 drawn through the center of gravity of the fixed counterweight 190. Finally, this structure consists of two mutually identical counterweights 1 whose angular position can be adjusted.
8, the counterweight 18 has the same dimensions as the adjustable counterweight at the front end of the engine 2, and can be adjusted relative to the fixed counterweight 19, by means of bolts 17, the adjustable counterweight at the front end of the engine 2. Like a counterweight, it is attached to the wheel joint.

As shown in FIG. 7, each adjustable counterweight 18 is guided in an annular groove 15 by an arcuate rib 23 projecting from the rear surface (ie, the surface facing disk 10) of the counterweight. An annular groove 24 (FIG. 8) is created in one of the cylindrical sides of each groove 150, and when the counterweight 18 is mounted on the disc 10 as shown in FIG. It comes to the same position in the axial direction as the opposing groove in the opposite side of the center. The sector has a protrusion that engages in the groove and is secured in the opposed groove in the cylinder n by bolts 26 (FIG. 7). Said sector 6 prevents the mounting from disengaging each counterweight 18 from the groove 15 while the bolt 17 is temporarily removed and the counterweight is adjusted. Although not shown in FIGS. 5 and 6, a similar structure is provided for rotating wheel applications.

Now, with the above-mentioned structure having fixed and adjustable counterweights, υ is the primary moment due to the inertial force generated in the engine 2 (f is the moment that changes with a period equal to the rotational speed of the engine crankshaft). It is explained how it is possible to influence the vibrations generated in the hull of the ship.

The unbalanced rotating masses of the engine, including the crank arm, crank bin and connecting rod portions, result in a moment Mrot. If the rotational speed (rpm) is constant, Mrot is constant and can be represented by a vector of constant length that rotates at the same rotational speed as the crankshaft. In other words, this moment acts periodically on all directions including the longitudinal axis of the ship, but in order to calculate the vibration effect on the ship's hull, it is necessary to calculate whether the moment acts in the vertical plane or in the horizontal plane. It is customary to consider only two cases:

The reciprocating masses of the engine (including the histones, piston rods, crossheads, and connecting rods) create a moment acting always in the vertical plane but whose thickness changes continuously during each revolution of the crankshaft. ” occurs. This moment can be represented by a vector of varying length but constant direction (vertical). In the four-cylinder engine shown in FIG. 2, the maximum value of this moment hMrec occurs when the rotating mass moment ) Mrot acts in the vertical plane. The crankshaft is 90' from the equivalent angle position
When rotated, Mrot acts in the horizontal plane and the moment of the reciprocating mass becomes O (zero).

Therefore, in an engine without the counterweight set 4°5 described above, the maximum value of the free moment will be M rec + M rot in the vertical plane and Mrot in the horizontal plane.

However, these maximum values of free moments can be determined by appropriate use of counterweight pairs 4 and 5.
can be reduced. As shown in FIGS. 2, 3 and 5, the counterweights have their respective centers of gravity 18
If they are mounted so that they are offset by 0°, the centrifugal force 6°7 in the opposite direction (Fig. 2) creates a balancing moment IQ1bal, which has a constant length and is synchronous with the crankshaft. may be represented by a vector which rotates to , but whose direction is always opposite to the direction of the rotation vector representing Mrot.

As explained above, by attaching the adjustable counterweight 18 to the fixed counterweights 13, 19 in different positions, it is possible to vary the magnitude of the forces 6, 7 and thus Mbal. Fixed counterweights 13 and 19 are the crankshaft 1
2, with only these two counterweights (i.e., without adding an adjustable counterweight)
It is mounted in an angular position such that the exerted balancing moment is directed in the opposite direction to the moment of the rotating mass Mrot.

Mass of fixed and adjustable counterweights and radius (distance) of their center of gravity from the centerline of the crankshaft
For example, if the maximum value of Mbal obtained by the adjustment shown in FIGS. 3 and 5 is approximately equal to (value when placed in position) can be chosen to be equal to Mrot.

When the counterweight 18 is adjusted to produce the maximum value of Mbal, the total free moment of inertia, i.e., M rot + M rec −M
bal is effectively zero in the vertical plane, but relatively large in the horizontal plane. Conversely, if the counterweight 18 is adjusted to produce a minimum value of Mbal, the moments acting in the horizontal plane may be reduced to zero or virtually zero, while the free moments acting in the vertical plane will not be tolerated. Must be.

Between the two extreme cases mentioned above, the moments acting on the adjustable counterweight 18 in the vertical and horizontal planes should be adjusted in such a way that the influence they have on the vibrations of the ship's hull in each of the abovementioned two planes is just. is made possible. The great advantage of the adjustable counterweight is that, after the ship has been put into service, it is possible to make adjustments to M ba l if it turns out that the initially calculated vibration phenomena do not correspond to the vibrations that actually appear. It is. The need for readjustment also arises during long voyages when it is desired to operate the ship at a different engine speed than the engine speed on which the initial adjustment was based.

In most ships, the natural or resonant frequency of the hull vibrations is different in the vertical and horizontal planes, so the Mb
The value of al is chosen with the aim of minimizing the moment of inertia created in one or the other of the surfaces. However, in some cases there may be particularly stringent requirements for reducing vibrations in all directions, and in such cases the fixed and adjustable counterweight constructions described above may be combined with the forces described below. Supplemented by a compensator, the previously mentioned periodically varying force 9 (FIG. 2) can be generated.

In the example to be described, ``Force 9 acts in the horizontal plane, and the actual mode of vibration of the ship's hull that occurs in the horizontal plane at frequencies within a range that includes the frequency corresponding to the nominal engine speed at maximum continuous power (MCR) is Assume that the deformation curve 27 in FIG. Curve 27 (which has been greatly exaggerated for clarity) has two nodes, of which the rear channel is located relatively far in front of engine 2.

If the natural frequency of vibration in the vertical plane occurs within the same frequency range, the vibration pattern at this frequency usually includes three nodes, the last node being located closer to the engine.

FIG. 9 shows a method for generating horizontal inertia force 9 by means of two identical counterweights 4 and 30 rotating in opposite directions at the same rotational speed. The counterweight 29 is attached to a sprocket 31 attached to the crankshaft 12, and the sprocket 31 drives the sprocket on the engine camshaft through a chain 32. , is attached to an idler sprocket rotatably held on a rocker arm 36 to maintain the desired tension in the chain 32. Counterweight 29, 3
If the zeros are placed symmetrically as shown in Figure 9, the vertical components of the centrifugal force (indicated by the radial arrows) acting on the counterweight will cancel and the horizontal components will add. A desired periodically varying compensation saw 9 is generated.

As shown in FIG. 2, the force 9 should always be directed in a direction opposite to the horizontal component of the cuff, and for the structure with the counterweight sets 4 and 5 described above, the hypothetical 11 counter It is possible to generate the deer 9 by the combination of the weight and the counterweight addition of 11 real++. The virtual counterweight 29 can be obtained by moving the counterweight 18 on the rotating wheel m away from a position corresponding to the position of the counterweight 18 on the disk 10 at the front end of the engine 2.

At this time, the counterweight 18 is adjusted as follows. , the total free moment in the vertical plane of all four counterweights relative to their respective fixed counterweights 13 or 19) Mrot + M
It is adjusted to take the (mutually symmetrical) angular position which produces the minimum value of rec -Mbal and therefore the maximum value of the free moment in the horizontal plane.

Counterweight 1 carried out at the front end of engine 2
8 is maintained, and the counterweight 18 at the rear end changes from the fixed counterweight 19 to the counterweight 19.
, 18 is 9050% of the desired force.
is moved away until it is reduced by an amount equal to . As is clear from the above, the remaining 50% of the force 9 is generated by the actual counterweight 30.

This operation corresponds to the distance II L I+(
2) is relatively thick, so that the moment of inertia occurring in the horizontal plane can be balanced by a relatively small force 9.

If the idle sprocket 35 in the camshaft drive means is designed to allow the installation of a counterweight I at a later date, the user can limit the moment of inertia without ever modifying the engine. Fixed and adjustable counterweights alone can be used to compensate for the force generated in the vessel, or the structure can be supplemented with additional force compensators such as those described above, thereby reducing the Vibration can be virtually completely eliminated. By changing the relative position of the counterweight 4 and the virtual counterweight 4, a compensating force 9 can be exerted in any arbitrary longitudinal plane, just as it is for the special factors influencing the vibration conditions. You can do it like this. for example,
There may be cases where the screw p moment about the axis caused by horizontal transverse forces acting below the longitudinal axis of the ship is undesirable;
is required to work in the vertical plane.

In this case, the above-mentioned adjustment of the adjustment counterweight 18 is changed as follows. That is, they are first adjusted to generate a moment of inertia that has a maximum value in the vertical plane and a minimum value in the horizontal plane. The moments acting in the vertical plane are then compensated by adjusting the counterweight is, 30 at the rear end of the engine.

Next, the virtual counterweight 29 for adding rotation wheel
The position of the counterweight 30 on the idle sedge rocket is diametrically opposite to that shown in FIG.

If there is no space to install four idler sockets 35 with the same diameter as the camshaft drive sprocket 31, the counterway 30 is attached to a shaft rotatably held by a swinging arm 36, It is driven from a small 1 air idler bracket held at a suitable gear ratio via a chain.

The moment of inertia of each pair of counterweights (i.e., the sum of the products of the mass of each counterweight multiplied by the square of the so-called radius of rotation or radius of inertia of the counterweights) is determined by moving the adjustable counterweights to the center of the crankshaft. Since the balancing moment does not change even when the shaft rotates around the line 9, the factors related to the thread vibration of the crankshaft remain unchanged and are therefore relevant to the design of the engine. The calculations made of the stresses caused by such vibrations remain valid.

[Brief explanation of the drawing]

FIG. 1 is an explanatory side view of a ship in which a multi-arbitrary internal combustion engine according to the present invention is used for propulsion, and FIG. Figure 3 is a plan view of the counterweight structure at the forward end of the engine, looking in the direction of the center line of the crankshaft; A side view of the structure, Figure 5 is a plan view similar to Figure 3 of the counterweight structure at the rear end of the engine, and Figure 6 is a side view of the structure.
The figure is a partial cross-sectional side view of the ditch in Figure 5, Figure 7 is an enlarged partial view taken along the line ■-■ in Figure 3, Figure 8 is a partial view taken along the line ■-■ in Figure 3, and Figure 9 The figure is an explanatory diagram of the camshaft drive means and force compensator of the engine. l...Ship, 2...Propulsion engine, 3...Globella, 4.5...Counterweight, 8...Counterweight, 18...Adjustable counterweight, 4...
Virtual counterweight, addition... real counterweight. procedure? iii Main gate (method) Kazuo Wakasugi, Commissioner of the Japan Patent Office 1 Indication of the case Patent application No. 6234 of 1982 Name of the invention Multi-cylinder internal combustion opening/opening 3 W, Deepil, Actisel Scab 4 agent Showa April 1959 4171 (Delivery date 1111 W59 1-April 24) 6? I
Ii Positive target condyle m applicant column, power of attorney, drawings. 7 Contents of amendment

Claims (1)

[Claims] 1) In a multi-cylinder internal combustion engine in which fixed counterweights (13, 19) are attached to the front and rear ends of the crankshaft (12) in order to balance the generated moment of inertia 7uc. , two mutually identical additional counterweights (18) are attached to each fixed counterweight, said additional counterweights being adjustable in the circumferential direction;
Each of them is connected to the fixed counterweight by a straight line (14
) for mounting in a selected angular position relative to (
17) A multi-cylinder internal combustion engine. 2) Each fixed counterweight (13, 19) is integral with a disc (10, 20) fixed to the crankshaft and has an annular groove (15) in which an adjustable counterweight (18) ) is engaged by an annular rib (23) on said groove (15), and in each of said grooves (15) a mounting for an adjustable counterweight is provided with an internally threaded hole (17) for receiving a hole (17). 16) A multi-cylinder internal combustion engine according to claim 4, characterized in that the multi-cylinder internal combustion engine is manufactured by: 3) The above straight line (14
) are made in two groups of screw holes (16) placed symmetrically on both sides of the screw holes, said screw holes being spaced equiangularly apart within each group. Multi-cylinder internal combustion engine described 1! ! , 1°4) In the -side of the annular groove (15) and in the opposite side of each lip (23), mutually matching grooves (24) are made, which grooves (24) are adjustable. During the adjustment of the counterweight (18), after the mounting plate (17) is removed, the counterweight (18) is removed.
The multi-cylinder internal combustion engine according to claim 2 or 3, characterized in that the multi-cylinder internal combustion engine serves to receive an arc-shaped locking body (25) capable of holding an arc-shaped locking body (25). 5) Lock body (25) with adjustable counter weight (18
5. Multi-cylinder internal combustion engine according to claim 4, characterized in that it has means (26) for removably attaching it to the engine. 6) Wheel (31) for driving the engine camshaft
) is mounted on the crankshaft (12) at one end of the engine, and as a further I# feature, an additional counterweight (3o) is mounted on the idle wheel (35) forming part of the camshaft drive means, as described above. A multi-cylinder internal combustion engine according to claim 1, wherein the idle wheel rotates in the opposite direction synchronously with the crankshaft.