JP2003269185A - Vibration reducing device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration reducing device for an internal combustion engine generating no impulsive hitting sound. <P>SOLUTION: This vibration reducing device for the internal combustion engine has a crankshaft, a main inertia mass body for integrally rotating with the crankshaft, an alternator for rotating according to rotation of the crankshaft, and a driving force transmitting mechanism for rotatably driving the alternator by transmitting rotational driving force of the crankshaft to the alternator. A crank pulley 6 for constituting the driving force transmitting mechanism has an inner peripheral part 20 directly joined to the crankshaft, and an outer peripheral part 21 arranged so as to be relatively rotatable to the inner peripheral part 20. The inner peripheral part 20 and the outer peripheral part 21 are connected via coil springs 24, 25, 26, and 27. These coil springs 24, 25, 26, and 27 are fixed to both the inner peripheral part 20 and the outer peripheral part 21. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vibration reducing device for an internal combustion engine.

[0002]

2. Description of the Related Art As a vibration reducing device for reducing roll vibration caused by fluctuations in combustion pressure of an internal combustion engine, for example, one disclosed in Japanese Patent Application Laid-Open No. 11-325186 has been conventionally known.

In Japanese Unexamined Patent Publication No. 11-325186, a driving force transmission mechanism for transmitting a rotational driving force of a crankshaft connected to a flywheel and a sub-inertial mass which is rotated by the driving force transmission mechanism to generate an inertial force. And a driving force transmission mechanism having an elastic body and a belt for transmitting the rotation of the crankshaft to the sub-inertial mass body via the elastic body, and the driving force transmission mechanism is generated by the rotation of the driving force transmission mechanism. The frequency of anti-resonance of the rotary vibration system of the auxiliary machine is calculated as (natural number /
2) A vibration reducing device is disclosed in which the vibration of the internal combustion engine in the operating state is reduced by making it substantially match with any one of the doubled frequencies.

[0004]

Considering the case where a metal spring is used as the elastic body of the driving force transmission mechanism in such a conventional vibration reduction device, FIGS. 12 and 13 are considered.
As shown in FIG.
4 As shown in FIG. 15, a case where a spring mechanism in which a coil spring 84 is combined is incorporated may be considered.

12 and 13 show an alternator pulley 70 having a spiral spring 77 incorporated therein. The alternator pulley 70 is an alternator (not shown) by the rotational driving force of a crankshaft (not shown) transmitted by the belt (not shown).
An outer peripheral portion 71 to which the rotational driving force of the crankshaft is transmitted by the belt, and a rotating shaft 73 of the rotor portion of the alternator.
An inner peripheral portion 72 directly fixed to the outer peripheral portion 71.
Are rotatably supported on the rotating shaft 73 of the rotor via bearings 74. The spiral spring 77 described above is fitted into the grooves 75 and 76 provided in the inner peripheral portion 72 and the outer peripheral portion 71.

However, as described above, the spiral spring 77
In the structure in which the spiral spring 77 is fitted into the grooves 75 and 76, after the spiral spring 77 is fitted, the grooves 75 and 76 and the spiral spring 77 are fitted.
An air gap is generated between the groove 75 and the portion fitted in the groove 76.

Further, in the above-mentioned conventional vibration reducing device, the antiresonance is set so as to be antiresonant under operating conditions frequently used such as during idle operation, and the frequency of this antiresonance is relatively higher than the frequency of resonance. Since the frequencies are close to each other, the spiral spring 77 is largely displaced at the time of anti-resonance.

Therefore, there is a problem that the spiral spring 77 and the alternator pulley 70 (the inner peripheral portion 71 and the outer peripheral portion 72) repeatedly collide with each other in the above-described gap, and an impact striking sound is generated by the collision.

On the other hand, FIGS. 14 and 15 show the structure of a crank pulley 80 incorporating a spring mechanism in which a coil spring 84 is combined. The spring mechanism incorporated in the crank pulley 80 is similar to, for example, the spring mechanism used in the damper part of the clutch provided between the normal engine and the manual transmission.

The crank pulley 80 has an inner peripheral portion 81 fixed to the crankshaft of the engine and an outer peripheral portion around which the belt (not shown) is wound and which is rotatably instructed via a bearing 83 on the crankshaft. 82 is divided into two parts, and the inner peripheral part 81 and the outer peripheral part 82 are connected via a spring mechanism in which four metal coil springs 84, which are elastic bodies, are combined.

The spring mechanism includes four coils in four window portions 88 constituted by openings of the same shape formed in the same place of each of the three plates 85, 86 and 87 which are placed in an overlapping manner. The springs 84 are arranged respectively. The first plate 85 sandwiched between the two plates 86 and 87 is fixed to the inner peripheral portion 81. The second plate 86 and the third plate 87 sandwiching the first plate 85 are fixed to the outer peripheral portion 82. That is, these three plates 85, 86, 87
Of the two, the outer two (second plate 86 and third plate 87) move integrally, and the inner plate (first plate 8
5) and the two outer plates (the second plate 86 and the third plate 87) are rotationally displaced relative to each other. By doing so, as shown in FIG. 16 and FIG. 17, the window portion 88 in which each coil pulling 84 fits is rotated regardless of positive or negative (clockwise is positive and counterclockwise is negative) rotational displacement. Since the space is narrowed, a force is always generated on each coil spring 84 on the compression side. However, in the case of an oscillating displacement in which the positive and negative of the displacement are always switched,
When the displacement changes from positive to negative or from negative to positive, the coil spring 84 and the first to third plates 85,
Since the contact surfaces of 86 and 87 are switched, at this time,
Coil spring 84 and first to third plates 85, 8
There is a problem that 6 and 87 collide with each other and an impact sound is generated.

[0012]

Therefore, the invention according to claim 1 is to provide a crankshaft for transmitting a driving force of an internal combustion engine as a rotational driving force, a main inertial mass body which rotates integrally with the crankshaft, and A sub-inertia mass body that rotates as the crankshaft rotates, and a drive force transmission mechanism that transmits the rotational driving force of the crankshaft to the sub-inertia mass body to rotationally drive the sub-inertia mass body. A vibration reduction device for an internal combustion engine, wherein the driving force transmission mechanism includes a pulley that rotates with rotation of the crankshaft, and the pulley is directly attached to a rotation shaft of the crankshaft or the sub-inertial mass body. It has a combined inner peripheral portion and an outer peripheral portion arranged so as to be rotatable relative to the inner peripheral portion, and the inner peripheral portion and the outer peripheral portion are n (n = natural number). Via spring element In the vibration reducing device for an internal combustion engine, the spring element is fixed to both the inner peripheral portion and the outer peripheral portion in order to reduce roll vibration of the internal combustion engine due to rotation of the crankshaft. It is characterized by This ensures that the spring element always moves integrally with the inner and outer circumferences.

According to a second aspect of the present invention, in the first aspect of the present invention, the spring element has a pair of elastic bodies whose one side is displaced in the extension direction and the other side is displaced in the compression direction. The elastic body is characterized in that one end is fixed to the inner peripheral portion and the other end is fixed to the outer peripheral portion. As a result, even if the elastic body has a non-linear spring characteristic in which the spring characteristic in the tension direction when stretched and the spring characteristic in the compression direction when compressed is different, one of the spring elements is stretched. Since it is composed of a pair of elastic bodies in which the other is compressed, a linear spring characteristic can be obtained as the spring characteristic of the entire spring element.

According to a third aspect of the invention, in the second aspect of the invention, the elastic body is a coil spring, and each coil spring comprises a coil portion and arm portions extending from both ends of the coil portion. A first plate that rotates integrally with the inner peripheral portion is attached to the inner peripheral portion, and a second plate that rotates integrally with the outer peripheral portion is attached to the outer peripheral portion and is formed on the first plate. And the first opening,
The coil spring is disposed in a window formed at a position where the second opening formed in the second plate and the second opening are overlapped with each other, and both ends of the coil spring of the coil spring are the openings of the first opening. It is fixed to the inner peripheral portion and the outer peripheral portion by being sandwiched by the edge and the opening edge of the second opening portion, and the coil springs are adjacent to each other along the circumferential direction of the pulleys of the adjacent coil springs. The end faces of the coil portions are in contact with the opening edges of the opening portions formed in the same plate of either one of the first plate and the second plate, and the pulleys of the adjacent coil springs are The arm portions that are adjacent to each other along the circumferential direction are connected by an adjusting mechanism whose length can be changed.

As a result, the coil portion of the coil spring always moves integrally with the first plate and the second plate.

According to a fourth aspect of the present invention, in the invention according to the third aspect, the adjusting mechanism includes a pair of shafts threaded in opposite directions and a nut connecting the shafts. , The shafts are
It is characterized in that the adjacent coil springs are respectively engaged with the adjacent arm portions along the circumferential direction of the pulleys.

According to a fifth aspect of the present invention, in the invention according to the third aspect, the adjusting mechanism includes a spring that connects adjacent arm portions of the adjacent coil springs along the circumferential direction of the pulleys. Is configured, the expansion and contraction direction component of the coil spring of the spring force generated by the spring,
It is characterized in that the coil length of the coil spring is set to be larger than the spring force generated when the coil length is maximally displaced.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the spring element is a spiral spring having a spiral shape on a plane orthogonal to the rotation axis of the pulley. The inner peripheral portion and the outer peripheral portion are connected via one spiral spring, the inner peripheral side of the spiral spring is fixed to the inner peripheral portion, and the outer peripheral side of the spiral spring is fixed to the outer peripheral portion. Is characterized by.

[0019]

According to the present invention, since the spring element always moves integrally with the inner peripheral portion and the outer peripheral portion of the pulley, the spring element and the inner peripheral portion, or the spring element, accompanying the expansion and contraction of the spring element. It is possible to prevent the impact hammering sound between the outer peripheral portion and the outer peripheral portion.

According to the second aspect of the present invention, even if the spring characteristic of the elastic body is a non-linear spring characteristic, a linear spring characteristic can be obtained as the spring characteristic of the entire spring element. The crankshaft and the rotating mass of the engine rotating part such as the flywheel attached to it,
The anti-resonance frequency of the vibration system in which the sub-inertial mass body is coupled by the spring element and the roll vibration of the engine or the fluctuation of the rotation of the crankshaft is multiplied by the rotation frequency (natural number / 2) at the predetermined rotation speed of the crankshaft. The frequency of the anti-resonance can be easily tuned when the vibration of the internal combustion engine is reduced by making it substantially equal to any one of the frequencies.

If an adjusting mechanism is provided as in the third to fifth aspects of the invention, the coil spring is always held between the first plate and the second plate, so that the inner peripheral portion of the coil spring is maintained. Also, it is possible to reliably prevent the impact striking sound between the coil spring and the first plate or between the coil spring and the second plate due to the rotation of the outer peripheral portion. Particularly, when a spring is used for the adjusting mechanism as in the invention of claim 5, even if the arm portion of the coil spring is deformed with time, the spring force of the spring deforms these members with time. Will be canceled out, so the coil part and the first plate,
It is possible to more reliably prevent the impact striking sound between the coil portion and the second plate.

[0022]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings.

1 and 2 show an internal combustion engine for an automobile equipped with a vibration reducing device according to the present invention. The engine 1 is provided with a crankshaft 3 having a flywheel 2 as a main inertial mass body at its rear end, and
Crankshaft 3 via alternator drive belt 4
An alternator 5 driven by is provided.

The alternator 5 includes a crank pulley 6 and
It is driven via a driving force transmission mechanism mainly composed of an alternator pulley 7 and an alternator drive belt 4 wound around these pulleys 6 and 7.

As shown in FIG. 3, the alternator 5 includes a rotating shaft 8 connected to an alternator pulley 7, a rotor portion 9 fixed to the outer periphery of the rotating shaft 8 as a sub-inertia mass body, and a housing 10. The stator coil 11 is fixed to the inner peripheral surface.

In the first embodiment, the alternator pulley 7 is divided into an inner peripheral portion 12 and an outer peripheral portion 13, and the inner peripheral portion 12 and the outer peripheral portion 13 have a spring element interposed therebetween. It is a combined structure.

That is, the alternator pulley 7 is shown in FIG.
As shown in FIG. 5, an inner peripheral portion 12 directly connected to the rotating shaft 8 and an outer peripheral portion 13 on which the alternator drive belt 4 is hooked and which is rotatably instructed to the rotating shaft 8 via bearings 14, 14. It is divided into two and these inner peripheral part 12
The outer peripheral portion 13 and the outer peripheral portion 13 are coupled to each other via a spiral spring 15 as a spring element that has a spiral shape on a plane orthogonal to the rotation axis 8.

The spiral spring 15 is fitted into the grooves 16 and 17 formed in advance in the inner peripheral portion 12 and the outer peripheral portion 13, respectively, and then these spiral springs 15 and 1 are inserted.
In FIG. 7, the spiral spring 15, the inner peripheral portion 12 and the outer peripheral portion 1 are formed so that no gap is formed between the grooves 16 and 17 and the spiral spring 15.
3 and 3 are welded together. That is, the inner peripheral side of the spiral spring 15 is fixed to the inner peripheral portion 12 of the alternator pulley 7, and the outer peripheral side of the spiral spring 15 is fixed to the outer peripheral portion 13 of the alternator pulley 7. In addition, 18, in FIG.
Reference numeral 18 is a welded portion for fixing the spiral spring 15 to the inner peripheral portion 12 and the outer peripheral portion 13 of the alternator pulley 7.

Here, in the vibration system in which the inertial mass of the crankshaft 3 and the engine rotating part such as the flywheel 2 attached thereto and the inertial mass of the rotor part 9 of the alternator 5 are connected by the spiral spring 15, There is a region in which the anti-resonance phenomenon, that is, the phenomenon in which the vibrations of the engine 1 and the rotation fluctuation of the crankshaft 3 mutually affect each other, and the vibrations of the both become in opposite phases to cancel each other's vibrations, that is, an antiresonance phenomenon occurs.

In the first embodiment, the anti-resonance frequency is set so as to match the fundamental rotation order during idle operation.

In the first embodiment, the inner and outer circumferences of the spiral spring 15 are welded to the inner and outer circumferences 12 and 13 of the alternator pulley 7, and the grooves 17,
18, the spiral spring 15 and the alternator pulley 7
It has a structure in which there is no gap between. That is,
Since the spiral spring 15 and the inner peripheral portion 12 and the outer peripheral portion 13 of the alternator pulley 7 can always move integrally, even if the spiral spring 15 is largely displaced at the time of anti-resonance, in these grooves 16 and 17, The spiral spring 15 and the inner peripheral portion 12 and the outer peripheral portion 13 of the alternator pulley 7 do not collide with each other, and the spiral spring 15 and the alternator pulley 7
It is possible to reliably prevent the impact hammering sound from being generated between the inner peripheral portion 12 and the outer peripheral portion 13.

Next, a second embodiment of the present invention will be described.

In the second embodiment, in the internal combustion engine for an automobile shown in FIGS. 1 and 2, the crank pulley 6 has an inner peripheral portion 2.
It has a structure in which it is divided into 0 and an outer peripheral portion 21, and the inner peripheral portion 20 and the outer peripheral portion 21 are connected via a spring element. The same components as those of the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

That is, in the crank pulley 6, as shown in FIGS. 6 and 7, the inner peripheral portion 20 directly connected to the crankshaft 3 by the bolts 22 and the alternator drive belt 4 are wound around the inner peripheral portion 20. Is divided into an outer peripheral portion 21 rotatably supported by a bearing 23 and an inner peripheral portion 20 and an outer peripheral portion 21 in combination with coil springs 24, 25, 26, 27 as elastic bodies. Coupled via a torsion spring mechanism as a spring element.

This torsion spring mechanism includes a first plate 2 fixed to the inner peripheral portion 20 of the crank pulley 6 with a mounting pin 28.
9 and the second plate 3 that is fixed by the outer peripheral portion 21 mounting pin 30 of the crank pulley 6 and that overlaps the first plate 29.
1 and 4 coil springs 24, 25, 26, 27
And is composed of.

The first plate 29 and the second plate 31 are arranged so as to be separated from each other at a predetermined interval along the rotation axis direction of the crank pulley 6.

Two first openings 32a and 32b are formed in the first plate 29, and two second openings 33a and 33b are formed in the second plate. And
By overlapping the first plate 29 and the second plate 31, the first opening portions 32a and 32b and the second opening portion 3 are formed.
Four windows 34a are provided at positions where 3a and 33b are overlapped with each other.
~ 34d are formed. More specifically, the window portion 34a in which the coil spring 24 is disposed has the first opening 32a.
And the second opening 33a are formed at the overlapping position, and the window portion 34b in which the coil spring 25 is disposed is formed at the overlapping position of the first opening portion 32b and the second opening portion 33a. The window portion 34c in which 26 is arranged is
The window portion 3 in which the first opening portion 32a and the second opening portion 33b are formed at the overlapping position and the coil spring 27 is arranged.
4d is formed at a position where the first opening 32b and the second opening 33b overlap.

Each coil spring 24, 25, 26, 2
7 is a substantially cylindrical coil portion 24a, 25a, 26a, 27a formed by spirally winding a metal wire, and arm portions 24b, 25b, 26b extending from both ends of these coil portions 24a, 25a, 26a, 27a. , 27b.

Each coil spring 24, 25, 26, 2
7, the both ends of each coil portion 24a, 25a, 26a, 27a are sandwiched between the opening edge of the first opening 32 and the opening edge of the second opening 33, so that the inner peripheral portion 20 of the crank pulley 6 and It is fixed to the outer peripheral portion 21. Further, the coil springs 24, 25, 26, 27 are arranged such that the coil portions 2 adjacent to each other in the circumferential direction of the crank pulley 6 are adjacent to each other.
The end faces of 4a, 25a, 26a, and 27a are in contact with the opening edges of the openings formed in the same one of the first plate 29 and the second plate 31.

That is, in the coil spring 24, the end surface 24aa of the coil portion 24a is in contact with the opening edge of the first opening 32a, and the end surface 24ab of the coil portion 24a is in contact with the opening edge of the second opening 33a. Coil spring 25
The end surface 25aa of the coil portion 25a is the second opening 33a.
Of the coil portion 25a, and the end face ab of the coil portion 25a abuts the opening edge of the first opening portion 32b. In the coil spring 26, the end surface 26aa of the coil portion 26a has the second opening 3
3b is contacted with the opening edge of the coil portion 26a, and the end surface 26ab of the coil portion 26a
Is in contact with the opening edge of the first opening 32a. In the coil spring 27, the end surface 27aa of the coil portion 27a is first
The end surface 27ab of the coil portion 27a abuts on the opening edge of the opening 32b, and the end surface 27ab of the coil portion 27a abuts on the opening edge of the second opening 33b.
Further, the end surface 2 of the coil portion 24a of the coil spring 24 is
4aa, the end face 24aa, and the coil portion 25 of the coil spring 25 adjacent to each other along the circumferential direction of the crank pulley.
The end surface 25ab of a is in contact with the opening edge of the first opening 32. Similarly, the coil portion 24 of the coil spring 24
end face 24ab of a and coil portion 2 of coil spring 26
The end surface 26aa of 6a is in contact with the opening edge of the second opening 33. The end surface 26ab of the coil portion 26a of the coil spring 26 and the end surface 27aa of the coil portion 27a of the coil spring 27 are in contact with the opening edge of the first opening 32. End face 27 of coil portion 27a of coil spring 27
ab and the end surface 2 of the coil portion 25a of the coil spring 25
5aa is in contact with the opening edge of the second opening 33.

The coil springs 24, 25, 26, 27 adjacent to each other along the circumferential direction of the crank pulley are provided.
The arms 24b, 25b, 26b, 27b are connected to each other by an adjusting mechanism 40 whose length can be changed. The adjusting mechanism 40 includes a pair of shafts 41, 41 threaded in opposite directions, and a nut 42 connecting the pair of shafts 41, 41.
And each shaft 41 includes a corresponding arm portion 24b, 25 of the coil spring 24, 25, 26, 27.
Protrusions 43 that engage with b, 26b, and 27b are formed, respectively.

That is, the arm portion 2 of the coil spring 24
4ba and the arm portion 25bb of the coil spring 25, and the arm portion 24bb of the coil spring 24 and the coil spring 26.
Arm part 26ba of the coil, arm part 26bb of the coil spring 26
The arm portion 27ba of the coil spring 27, the arm portion 27bb of the coil spring 27 and the arm portion 25ba of the coil spring 25 are connected by the adjusting mechanism 40, respectively.

Each shaft 4 of the adjusting mechanism 40
The projections 43 provided on the first plate 41 and the first plate 29 are
Alternatively, the second plate 31 is disposed in the groove portion 45 formed along the expansion / contraction direction of the corresponding coil spring,
Along the groove 45, the coil spring can be moved along the expansion / contraction direction of the coil spring. The groove 45
Are formed so as to be continuous with the first opening 32 or the second opening 33. The grooves 45a and 45b are formed in the first plate 29 and are continuous with the first opening 32a, and the groove 45 is formed.
c and 45d are formed in the first plate 29 and are formed in the first opening 3
2b and the grooves 45e and 45f are formed on the second plate 31.
Which is continuous with the second opening 33a and is formed in the groove 45g, 4g
5h is formed on the second plate 31 and is continuous with the second opening 33b.

Further, the first plate 29 and the second plate 3
When the coil spring 24 and the coil spring 2 are rotated relative to each other and the opening area of the window portion 34a in which the coil spring 24 is disposed is reduced as shown in FIG.
5, the coil spring 24 is displaced in the compression direction and the coil spring 25 is displaced in the extension direction.
Similarly, the coil spring 26 and the coil spring 27
Paying attention to, the coil spring 26 is displaced in the extension direction, and the coil spring 27 is displaced in the compression direction. When the first plate 29 and the second plate 31 relatively rotate in the direction in which the opening area of the window 34a increases, the coil spring 24 is displaced in the extension direction and the coil spring 25 is displaced in the compression direction. The coil spring 26 is displaced in the compression direction, and the coil spring 27 is displaced in the extension direction.

Each coil spring 24, 25, 2
The spring constants of 6, 27 are the same as in the above-described first embodiment.
This anti-resonance frequency is set to match the fundamental rotation order during idle operation.

According to the second embodiment constructed as described above, when the nut 42 of the adjusting mechanism 40 is tightened, the protrusion 43 is moved in the expansion / contraction direction of the corresponding coil spring, and the coil portions 24a, 25a. , 26a, 2
Each end surface of 7a has a first opening 32 or a second opening 33.
And the coil springs 24,
25, 26, 27 arm portions 24b, 25b, 26b, 27
In the state where there is no play, b is engaged with each of the protrusions 43. Therefore, each coil spring 24, 25,
It is possible to prevent the impact tapping sound from being generated when the 26 and 27 are vibratingly displaced.

Further, each coil spring 24, 25, 2
When the coils 6 and 27 are displaced in the compression direction, only the coil portions 24a, 25a, 26a and 27a function as springs, but when they are displaced in the extension direction, the arm portions 24b and 25 are provided.
Since b, 26b, and 27b also function as springs, the spring characteristics during compression and the spring characteristics during extension have different nonlinearities. When the spring element of the vibration reduction device is configured using such a non-linear spring, the anti-resonance frequency described above changes due to the load of the engine, and tuning of the vibration reduction device becomes difficult.

However, in the second embodiment, when the first plate 29 and the second plate 31 rotate relatively, the four coil springs 24, 25,
Two of 26 and 27 are always displaced in the compression direction, and the other two are always displaced in the extension direction. Therefore, by canceling each other, the spring characteristics of the torsion spring mechanism as a whole can be made linear. Yes, the anti-resonance frequency is
It becomes constant regardless of the engine load, and the vibration reduction device can be easily tuned.

Next, a third embodiment of the present invention will be described. In the third embodiment, the adjusting mechanism 40 in the second embodiment described above is changed to one using a spring. The same components as those of the second embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

Adjusting mechanism 4 in the third embodiment
As shown in FIGS. 9 to 11, the reference numeral 9 designates coil springs 24, 2 which are adjacent to each other in the circumferential direction of the crank pulley.
5, 26, 27 arm portions 24b, 25b, 26b, 27
Adjust springs 50a to 50d for connecting b,
The arm portions 51a to 51d of the adjusting springs 50a to 50d and the arm portions 24b, 25b of the coil springs 24, 25, 26, 27 are arranged in the groove portions 45a to 45h formed in the first plate 29 or the second plate 31, respectively.
26b, 27b and a pin 52 that engages.

Here, as shown in FIG. 11, the groove portions 45a to 45h are formed on both side walls of the groove portion 45 facing each other in the longitudinal direction of the groove portion 45, that is, the corresponding coil springs 2.
Recesses 53, 53 are formed continuously along the expansion / contraction direction of 4, 25, 26, 27, respectively. And pin 5
2, a convex portion 54, which engages with these concave portions 53, 53,
54 is formed.

That is, the adjusting springs 50a-5
0d arm portions 51a to 51d and coil springs 24 and 2
5, 26, 27 arm portions 24b, 25b, 26b, 27b
Are engaged with the pins 52 by sandwiching the plate (one of the first plate 29 or the second plate 31) on which the pins 52 are arranged, respectively.

In addition, each adjusting spring 50a-5
Each spring force α of 0d corresponds to the corresponding coil spring 24,
25, 26, 27, the expansion / contraction direction component α1 of the coil spring of this spring force α is at the maximum displacement of this torsion spring mechanism, that is, the coil springs 24, 25, 26, 2
When the coil length of 7 is maximally displaced, it is set to be larger than the spring force β generated in the maximally displaced coil springs 24, 25, 26, 27. In other words, the coil spring 2 when each displacement at resonance occurs
The spring force α of each of the adjusting springs 50a to 50d is set so that the expansion / contraction direction component α1 of the spring force α of the adjusting springs 50a to 50d along the coil spring expanding / contracting direction becomes larger than the spring force β of the 4, 25, 26, 27. It is set.

Each coil spring 24, 25, 2
The spring constants of 6, 27 are the same as in the above-described first embodiment.
This anti-resonance frequency is set to match the fundamental rotation order during idle operation.

According to the third embodiment constructed as described above, the adjusting springs 50a-5a are always exerted with a force that overcomes the spring force β of the coil springs 24, 25, 26, 27.
0d pulls the arm portions 24b, 25b, 26b, 27b of the coil springs 24, 25, 26, 27, so that the coil springs 24, 25, 26, 27 are changed over time.
Even if the arm portions 24b, 25b, 26b, and 27b of the robot are stretched, the coil portions 24a, 25a, 26a, and 2
Each end surface of 7a has a first opening 32 or a second opening 33.
Since the coil springs 24, 25, 26, 27 are vibratingly displaced, it is possible to prevent the impact striking sound from being generated.

In the above-mentioned second and third embodiments, the torsion spring mechanism having two spring elements each consisting of a pair of coil springs has been described. However, the number of spring elements consisting of a pair of coil springs is described. May be one or two or more, and in that case, 2n (n is a natural number) windows are formed in the first plate and the second plate according to the number of spring elements. First opening and second respectively
The openings may be formed appropriately.

[Brief description of drawings]

FIG. 1 is a front view of an engine including a vibration reduction device according to the present invention.

FIG. 2 is a side view of an engine including a vibration reduction device according to the present invention.

3 is a partial cross-sectional view of the alternator shown in FIG.

FIG. 4 is a cross-sectional view of an alternator pulley showing a main part of the first embodiment of the present invention, which is a cross-sectional view taken along the line AA of FIG.

5 is a cross-sectional view taken along the line BB of FIG.

FIG. 6 is a sectional view of a crank pulley showing an essential part of a second embodiment of the present invention.

7 is a cross-sectional view taken along the line CC of FIG.

FIG. 8 is a schematic diagram showing the alternator pulley shown in FIG.
Explanatory drawing which shows the state which the plate and the 2nd plate relatively rotated.

FIG. 9 is a sectional view of a crank pulley showing an essential part of a third embodiment of the present invention.

10 is a cross-sectional view taken along the line DD of FIG.

11 is a cross-sectional view taken along the line EE of FIG.

FIG. 12 is a cross-sectional view of a conventional alternator pulley.

13 is a cross-sectional view taken along the line FF of FIG.

FIG. 14 is a sectional view of a conventional crank pulley.

FIG. 15 is a cross-sectional view taken along the line GG of FIG.

FIG. 16 is a functional explanatory view of a conventional torsion spring mechanism.

FIG. 17 is a functional explanatory view of a conventional torsion spring mechanism.

[Explanation of symbols]

6 ... Crank pulley 20 ... Inner circumference 21 ... Outer periphery 24 ... Coil spring 25 ... Coil spring 26 ... Coil spring 27 ... Coil spring

Claims (6)

[Claims] 1. A crankshaft for transmitting a driving force of an internal combustion engine as a rotational driving force, a main inertial mass body that rotates integrally with the crankshaft, and a sub-inertia mass body that rotates with the rotation of the crankshaft. A vibration reduction device for an internal combustion engine, comprising: a drive force transmission mechanism that transmits the rotational drive force of the crankshaft to the sub-inertial mass body to rotationally drive the sub-inertial mass body. Has a pulley that rotates with the rotation of the crankshaft, the pulley having an inner peripheral portion directly coupled to the crankshaft or the rotation shaft of the sub-inertia mass body, and the inner peripheral portion with respect to the inner peripheral portion. And an outer peripheral portion arranged so as to be rotatable relative to each other, wherein the inner peripheral portion and the outer peripheral portion are n pieces (n = natural number)
In the vibration reduction device for an internal combustion engine, which is connected via a spring element for reducing the roll vibration of the internal combustion engine due to the rotation of the crankshaft, the spring element includes both the inner peripheral portion and the outer peripheral portion. A vibration reduction device for an internal combustion engine, which is fixed to the. 2. The spring element has a pair of elastic bodies, one of which is displaced in the compression direction when the other is displaced in the extension direction,
The vibration reducing device for an internal combustion engine according to claim 1, wherein one end of each of the elastic bodies is fixed to the inner peripheral portion, and the other end of the elastic body is fixed to the outer peripheral portion. . 3. The elastic body is a coil spring, and each coil spring includes a coil portion and arm portions extending from both ends of the coil portion, and the inner peripheral portion rotates integrally with the inner peripheral portion. A first plate is attached, a second plate that rotates integrally with the outer peripheral portion is attached to the outer peripheral portion, a first opening formed in the first plate, and the second opening
The coil spring is disposed in a window formed at a position where the second opening formed in the plate overlaps with each other, and both ends of the coil spring of the coil spring are the opening edges of the first opening. By being sandwiched by the opening edge of the second opening portion, the coil portion is fixed to the inner peripheral portion and the outer peripheral portion, and of the coil portions adjacent to each other along the circumferential direction of the pulleys of the adjacent coil springs. The end faces are in contact with the opening edge of the opening formed in the same plate of either the first plate or the second plate, and further, in the circumferential direction of the pulleys of the adjacent coil springs. The vibration reducing device for an internal combustion engine according to claim 2, wherein the arms that are adjacent to each other along the line are connected by an adjusting mechanism that can change the length of the arms. 4. The adjusting mechanism includes a pair of shafts that are threaded in opposite directions and a nut that connects the shafts, and each shaft has a circumference of the pulley of adjacent coil springs. The vibration reduction device for an internal combustion engine according to claim 3, wherein the vibration reduction device is engaged with each of the adjacent arm portions along the direction. 5. The adjusting mechanism is composed of a spring that connects adjacent arm portions of the adjacent coil springs along the circumferential direction of the pulleys of the adjacent coil springs, and the expansion and contraction of the coil spring by the spring force generated by the springs. The vibration reduction device for an internal combustion engine according to claim 3, wherein the directional component is set to be larger than a spring force generated when the coil length of the coil spring is maximally displaced. 6. The spiral element is a spiral spring having a spiral shape on a plane orthogonal to a rotation axis of the pulley, wherein the inner peripheral portion and the outer peripheral portion have one spiral spring interposed therebetween. 2. The vibration reducing device for an internal combustion engine according to claim 1, wherein the inner peripheral side of the spiral spring is fixed to the inner peripheral portion, and the outer peripheral side of the spiral spring is fixed to the outer peripheral portion. .