JPH11311298A - Vibration reducing device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of torsional resonance of a practical rotation area by setting a resonance frequency of torsional vibration by an inertial mass body joined to a sun gear of a planetary gear mechanism larger than a roller vibration frequency at engine maximum rotating speed time. SOLUTION: When a crankshaft 12 is rotated, an internal gear 14 of a planetary gear mechanism rotates integrally with the crankshaft 12, the internal gear 14 meshes with a sun gear 22, and the sun gear 22 rotates so as to increase a speed in the inverse direction of the rotational direction of the crankshaft 12 through a revolution-prohibited planetary gear 19. In this case, an inertial mass body 25 is joined to the sun gear 22 so that a resonance frequency of torsional vibration between the sun gear 22 and a crank pulley as the inertial mass body 25 becomes larger than a dominant roller vibration frequency at a maximum rotating speed of an engine to thereby prevent the occurrence of resonance of torsional vibration in a practical rotation area of the engine as well as to efficiently reduce vibration of a roller of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration reducing device for reducing the vibration of an internal combustion engine itself caused by the rotation of the internal combustion engine, and more particularly, to a vibration reducing device using an inertial mass rotating in the opposite direction to a crankshaft. The present invention relates to a vibration reduction device for an internal combustion engine that reduces roll vibration of a vehicle.

[0002]

2. Description of the Related Art In recent years, interest in improving fuel efficiency of automobiles in response to environmental problems has increased, and as an internal combustion engine (engine) mounted on automobiles, a direct injection gasoline engine or a direct injection gasoline engine that directly injects fuel into a cylinder. Diesel engines are in the limelight, but these engines have higher combustion excitation force than conventional engines, so the roll vibration accompanying torque fluctuations is also large. There is a problem that the muffled sound and the floor vibration of the vehicle body deteriorate.

[0003] One method for solving such a problem is as follows.
For example, as shown in Japanese Patent Application Laid-Open No. 6-42591, by adding a separate auxiliary flywheel that rotates in the reverse direction to the flywheel directly attached to the crankshaft,
2. Description of the Related Art There is a vibration reduction device that generates a moment acting in the opposite direction to a moment acting on an engine body as a reaction to the generation of torque, thereby reducing roll vibration of the engine body.

In addition, the above-described vibration reducing apparatus causes problems such as an increase in the mass of the engine and a space for arranging the sub flywheel. For example, Japanese Patent Laid-Open No. 7-35199 discloses a method for solving these problems. As shown in the official gazette, etc., vibration reduction that reduces the roll vibration of the engine by effectively utilizing the existing inertial mass body, which is an auxiliary component of the engine, without adding a new heavy object such as an auxiliary flywheel There is a device.

As shown in FIGS. 6 and 7, the vibration reduction device disclosed in Japanese Patent Application Laid-Open No. 7-35199 has a structure in which a crankshaft 2 and a crank pulley 3 of an engine 1 are disposed between the crankshaft 2 and the crank pulley 3.
A planetary gear mechanism including an internal gear 4, a planetary gear 5, a sun gear 6, etc. is interposed, and a crankshaft 2
And the internal gear 4 of the planetary gear mechanism are connected so as to rotate integrally, and the crank pulley 3 and the sun gear 6 of the planetary gear mechanism are connected by a shaft 7 so as to rotate integrally. The planetary gear 5 is prevented from revolving, and the crank pulley 3 is rotated in a direction opposite to the direction of rotation of the crankshaft 2. Are linked by a belt 9 so that the inertial mass body of the alternator 8 is
Is rotated in the direction opposite to the direction of rotation.

[0006]

However, in the vibration reducing device disclosed in Japanese Patent Application Laid-Open No. 7-35199, if the torsional rigidity of the shaft connecting the sun gear and the crank pulley is insufficient, the engine rotation speed may exceed a certain value. In the region, there is a problem that the torsional resonance worsens the roll vibration of the engine.

[0007] The present invention has been made in view of such problems of the prior art.
In a torsional vibration system from a sun gear to a crank pulley, to prevent the occurrence of torsional resonance in the practical rotation range of the engine, and to provide a vibration reduction device for an internal combustion engine capable of efficiently reducing the roll vibration of the engine. is there.

[0008]

According to a first aspect of the present invention, there is provided a vibration reducing device for an internal combustion engine, comprising: a sun gear; a planetary gear held by a carrier so as to mesh with the sun gear; and a planetary gear. A planetary gear mechanism that includes an internal gear that meshes with an internal gear; and an inertial mass body that is rotated by the operation of the planetary gear mechanism to generate an inertial force. The internal gear is integrally coaxial with a crankshaft. The carrier is fixed to the crankshaft so that the planetary gear rotates, and the inertial mass is integrally formed with the sun gear in a direction opposite to the rotation direction of the crankshaft. To reduce the roll vibration of the internal combustion engine due to the rotation of the crankshaft. A vibration reduction device for a fuel engine, wherein the resonance frequency fn of torsional vibration between the inertial mass body and the sun gear is higher than the dominant roll vibration frequency f at the maximum rotation speed of the internal combustion engine. The inertia mass body and the sun gear are connected.

The planetary gear mechanism includes a sun gear, a planetary gear held by a carrier so as to mesh with the sun gear, and an internal gear meshing with the planetary gear. An inertial mass body that is rotated by operation of a gear mechanism to generate an inertial force, wherein the internal gear is fixed to the crankshaft so as to rotate integrally and coaxially with the crankshaft, and the carrier is The inertial mass is fixed to prohibit revolution of the planetary gear, and the inertial mass is formed to rotate integrally with the sun gear in a direction opposite to a rotation direction of a crankshaft, and includes the inertial mass and a sun gear. Rolls of the internal combustion engine accompanying the rotation of the crankshaft by generating canceling torque by the rotating body An apparatus for reducing vibration of an internal combustion engine, wherein the amplitude of the cancel torque amplified by torsional vibration between the inertial mass body and the sun gear substantially matches the amplitude of torque fluctuation of the internal combustion engine. The inertia mass body and the sun gear are coupled so that the torsional vibration frequency fo at the time of the rotation is higher than the dominant roll vibration frequency f at the maximum rotation speed of the internal combustion engine.

According to a third aspect of the present invention, in the vibration reducing device for an internal combustion engine according to the first and second aspects,
The moment of inertia of the inertial mass is I _f , the shear modulus of elasticity of the joint between the inertial mass and the sun gear is G,
Assuming that the secondary pole moment of area of the coupling portion is I _p and the axial length of the coupling portion is L, the dominant roll vibration frequency f is Is satisfied, the inertial mass body and the sun gear are combined.

According to a fourth aspect of the present invention, in the vibration reducing apparatus for an internal combustion engine according to any one of the first to third aspects, the apparatus further includes a shaft connecting the inertial mass and the sun gear, wherein the shaft is A small-diameter portion and a large-diameter portion, wherein the inertial mass body is coupled at a large-diameter portion of the shaft by rotational movement restraining means for restricting relative rotational movement, and at a small-diameter portion of the shaft, The shafts are connected by a translational movement restricting means for restricting a relative translational movement in the axial direction of the shaft.

According to a fifth aspect of the present invention, in the vibration reducing device for an internal combustion engine according to any one of the first to fourth aspects, a shaft for connecting the inertial mass body and the sun gear is provided. The sun gear has a small-diameter portion and a large-diameter portion, and the sun gear is connected to the large-diameter portion of the shaft by a rotational movement restricting unit that restricts relative rotational movement.

According to a sixth aspect of the present invention, in the vibration reducing device for an internal combustion engine according to the fourth and fifth aspects,
The rotation movement restricting means is configured by a spline connection provided between an inner peripheral surface of a cylindrical portion formed on the inertial mass body and an outer peripheral surface of a large diameter portion of the shaft.

According to a seventh aspect of the present invention, in the vibration reducing device for an internal combustion engine according to the fourth and fifth aspects,
The rotation movement restraining means is constituted by a key connection provided between an inner peripheral surface of a cylindrical portion formed on the inertial mass body and an outer peripheral surface of a large diameter portion of the shaft.

Further, as set forth in claim 8, in the vibration reducing device for an internal combustion engine according to claims 4 and 5,
The rotational movement restraining means is configured by a meshing clutch connection provided between a cylindrical portion formed on the inertial mass body and a large diameter portion of the shaft.

Further, as described in claim 9,
5. The vibration reduction device for an internal combustion engine according to claim 4, wherein the translational movement restraining unit is configured to insert the small-diameter portion of the shaft into a fitting hole formed in a center portion of the inertial mass body. In order to press the inertial mass body toward the end face of the step portion between the small diameter portion and the large diameter portion, a nut or a bolt screwed into a screw portion formed in the small diameter portion of the shaft is included. ing.

[0017]

According to the vibration reducing device for an internal combustion engine according to the first aspect of the present invention, when the crankshaft rotates, the internal gear of the planetary gear mechanism rotates integrally with the crankshaft. Through the planetary gear which meshes with the gear and the sun gear and whose revolution is prohibited, the sun gear is accelerated in the direction opposite to the rotation direction of the crankshaft and rotates in the reverse direction. And, when the inertia mass body or the inertial mass body is a crank pulley together with the sun gear that rotates at an increased speed, the accessories and the like that are driven in conjunction with the crank pulley are also accelerated and rotated at a reduced speed, This acts as a cancel torque for canceling the torque reaction force that is the root of the roll vibration.

At this time, the resonance frequency (natural frequency) fn of the torsional vibration between the inertial mass body (or the crank pulley as the inertial mass body) and the sun gear becomes the dominant roll vibration at the maximum rotation speed of the internal combustion engine. Since the inertial mass body and the sun gear are coupled so as to be higher than the frequency f, the resonance phenomenon of the torsional vibration can be prevented from appearing in the practical rotation range of the internal combustion engine. Roll vibration of the internal combustion engine can be efficiently reduced.

According to the vibration reducing device for an internal combustion engine according to the second aspect of the present invention, when the crankshaft rotates, the internal gear of the planetary gear mechanism rotates integrally with the crankshaft. Via a planetary gear that meshes with the sun gear and is prohibited from revolving,
The sun gear is accelerated in the direction opposite to the direction of rotation of the crankshaft, and reversely rotates. And, when the inertia mass body or the inertial mass body is a crank pulley together with the sun gear that rotates at an increased speed, the accessories and the like that are driven in conjunction with the crank pulley are also accelerated and rotated at a reduced speed, This acts as a cancel torque for canceling the torque reaction force that is the root of the roll vibration.

[0020] In this case, the torsional vibration frequency f _o at which the amplitude of the torque variation of the amplitude and the internal combustion engine of the torsion the cancel torque amplified by the vibration between the inertial mass and the sun gear are substantially matched, the internal combustion engine Since the inertial mass and the sun gear are coupled so as to be higher than the dominant roll vibration frequency f at the maximum rotation speed of the internal combustion engine, the resonance of the torsional vibration appears within the practical rotation range of the internal combustion engine. Can be reliably prevented, and torsional vibration can be further suppressed, whereby the roll vibration of the internal combustion engine can be more efficiently reduced.

According to the vibration reducing device for an internal combustion engine according to the third aspect of the present invention, in the torsional vibration system from the inertial mass body to the sun gear, the resonance frequency (natural frequency) of the torsional vibration can be estimated by desktop calculation, From the design stage, the resonance frequency can be set in advance so as to deviate from the practical rotation range of the internal combustion engine. For example, by setting N = 1.2, it is possible to perform a desk-top study within a practical rotation range of the internal combustion engine without previously investigating the torsional vibration frequency when the amplitude of the cancel torque coincides with the amplitude of the torque fluctuation of the internal combustion engine. It is possible to prevent the torsional resonance phenomenon from appearing, thereby reducing the roll vibration.

According to the vibration reducing device for an internal combustion engine according to the fourth aspect of the present invention, when the rotational force is transmitted from the sun gear to the inertial mass via the shaft, the inertial mass is formed at the large diameter portion of the shaft. Since they are coupled so as to rotate integrally, high torsional rigidity can be ensured, and the resonance frequency of torsional vibration can be set so as to be outside the practical rotation range of the internal combustion engine. In addition, since the inertial mass body is integrally connected to the shaft so as not to move in the axial direction at the small diameter portion of the shaft, it is possible to reduce the weight at a portion that does not require high torsional rigidity.

According to the vibration reducing device for an internal combustion engine according to claim 5 of the present invention, when the rotational force is transmitted from the sun gear to the inertial mass body via the shaft, the sun gear
Since the shaft is joined so as to rotate integrally at the large diameter portion, high torsional rigidity can be secured, and the resonance frequency of the torsional vibration can be set so as to be outside the practical rotation range of the internal combustion engine. .

According to the vibration reducing device for an internal combustion engine according to claims 6 to 8 of the present invention, the inertial mass body and the sun gear are easily and securely fixed to the large-diameter portion of the shaft, so that the relative mass in the rotational direction can be increased. Movement can be restricted.

According to the vibration reducing apparatus for an internal combustion engine according to the ninth aspect of the present invention, standard parts can be used as nuts or bolts for tightening and fixing the inertial mass body to the shaft. Thus, the cost can be reduced.

[0026]

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

FIG. 1 shows an embodiment of a vibration reducing device for generating a cancel torque for canceling roll vibration by driving an auxiliary machine by the driving force of an engine.
In this vibration reduction device 10, as shown in FIG.
A chain sprocket 13 for driving a valve train is externally fitted and fixed to a reduced diameter portion 12a protruding from an end surface 11a of the cylinder block, of a crankshaft 12 rotatably provided on a cylinder block 11 of the engine body. On the distal end side, an internal gear 14 forming a part of a planetary gear mechanism is externally fitted, and is fixed to the crankshaft 12 by bolts 15 and washers 16.

The internal gear 14 includes a cylindrical portion 14a having internal teeth 14a 'formed on the inner peripheral surface thereof, and a cylindrical portion 1a.
4a is formed of a flat flange portion 14b or the like which is fixed to the crankshaft 12 and is fixed to one end of the crankshaft 12, and the fixed portion 14b 'is formed in a cylindrical shape and has an outer peripheral surface. A fitting portion 14c is formed to be fitted to the inner rotor 18a of the oil pump 18 incorporated in the front cover 17.

The planetary gear 19 meshing with the internal gear 14 is rotatable on a carrier cover 21 as a carrier fixed to the end face 17a of the front cover 17 or the end face 11a of the cylinder block 11 by a bolt or the like via a gasket 20. That is, in the circumferential direction of the internal gear 14, for example, three (only two are shown in the drawing) support shafts 21a that are implanted on the carrier cover 40 at equal intervals (center angle of 120 degrees) are rotatable. And is prevented from falling off from the support shaft 21a by the stopper piece 21b. Here, since the carrier cover 21 that supports the planetary gear 19 is fixed to the front cover 17 (that is, the cylinder block 11), the planetary gear 19 is in a state where its revolution is prohibited.

A sun gear 22 meshing with the planetary gear 19 is attached to an inner large-diameter portion 24a of a shaft 24 rotatably supported by a bearing 23 press-fitted into a carrier cover 21 by spline coupling. It is designed to rotate integrally with 24,
On the other hand, the shaft 2 protruding outside the carrier cover 21
A crank pulley 25 as an inertial mass body for driving an auxiliary machine is externally fitted to the outer large-diameter portion 24b and the small-diameter portion 24c of the outer cylinder 4, and is fixed to the shaft 24 by being tightened by a nut 26 and a washer 27. . An oil seal 28 is fitted between the carrier cover 21 and the shaft 24 in a region outside the bearing 23, so that a space surrounded by the carrier cover 21 is sealed.

Since helical gears are used as the internal gear 14, the planetary gear 19, and the sun gear 22, the thrust bearings 29, 3 are used to absorb the effect of the thrust force generated in the axial direction.
0 is set.

FIG. 2 shows the sun gear 22 and the shaft 2
4 shows the coupling relationship between the crank gear pulley 25 and the sun gear 22. The sun gear 22 is spline-coupled to the inner large-diameter portion 24a of the shaft 24 as a rotational movement restraining means as shown in FIG. The crank pulley 25 has a cylindrical portion 25a formed on the inner surface of the crank pulley 25 similarly to the outer large-diameter portion 24b of the shaft 24 as shown in FIG. And a fitting hole 25b formed in the center of the shaft 24 is fitted outside the small diameter portion 24c of the shaft 24. A nut 26 is screwed into a male screw 24c 'serving as a screw portion provided on the distal end side of the small diameter portion 24c with a washer 27 interposed therebetween. 24d and as will be pinched by the end face of the nut 26 (and washers 27), i.e., the crank pulley 25 is stepped end face 24d by a nut 26
, So that the movement of the shaft 24 in the axial direction is restricted. It should be noted that a flanged nut may be used instead of the nut 26 and the washer 27, and a female screw hole may be formed as a screw portion instead of the male screw 24c ', and a bolt and a washer or a flanged bolt may be used. It is also possible. With such a configuration, for example, standard-sized components such as M16 nuts or bolts can be used.

The nut 26 (or bolt), washer 27, male screw 24c '(or female screw hole), step end face 24d, and the like restrain the crank pulley 25 from relatively translating in the axial direction of the shaft 24. A translation movement restricting means is configured.

In addition to the spline connection, for example, a key connection as shown in FIG. 3A or an engagement clutch connection as shown in FIG. Jaw clutch connection (dog clutch connection) or the like.

Since the carrier cover 21 is formed so as to cover the internal gear 14 and the like which are rotating bodies, it is possible to prevent other parts from interfering with these rotating bodies,
Also, it prevents dust, dust, muddy water and the like from entering the planetary gear mechanism.

On the other hand, in the planetary gear mechanism housed in the carrier cover 21, lubricating oil guided from a lubricating oil path (not shown) provided in the cylinder block 11 is engaged with the sun gear 22 and the planetary gear 19 in an engagement region. The lubricating oil is supplied to a meshing region between the planetary gear 19 and the internal gear 14 to perform a lubricating operation. The lubricating oil used for the lubricating operation is then returned to an oil pan (not shown). Then, the oil is guided again to the lubricating oil path through an oil filter (not shown).

Next, the operation of the planetary gear mechanism and the crank pulley 25 will be described with reference to FIG. FIG.
As shown in (a), assuming that the engine body generates a torque T (T is a function of time) due to the explosive force at the time of combustion, the internal gear 14 directly connected to the crankshaft 12 has the torque T T, a drag N from the planetary gear 19, and a reaction N generated as a result of supporting the drag N with its rotating shaft.

Also, assuming that the moment of inertia of the planetary gear 19 is sufficiently small,
, A driving force N from the internal gear 14, a reaction force N from the sun gear 22, and a reaction force 2N resulting from supporting the driving force N and the reaction force N on the rotating shaft.

Further, a driving force N from the planetary gear 19 and a reaction force N generated as a result of supporting the driving force by its rotating shaft portion act on the sun gear 22.

On the other hand, as shown in FIG. 4B, a reaction torque -T generated as a reaction of the torque T generated by the explosion force and a reaction generated by the reaction force generated in the rotating shaft of each gear are applied to the engine body. And the force generated as an action. This force has a magnitude of 2N and a moment arm length of R _s + R _p
(Where R _s indicates the pitch circle radius of the sun gear 22 and R _p indicates the pitch circle radius of the planetary gear 19), and acts as a reverse couple of the anti-torque −T of the engine body. This couple acts as a cancel torque that cancels the counter torque -T, and as a result, the roll vibration of the engine body is reduced.

Here, the moment of inertia around the roll axis of the engine body is Ι, the roll displacement angle of the engine body is φ, and the rotation system of the engine body (flywheel or drive plate, crankshaft 12, connecting rod rotation equivalent part, The moment of inertia of the internal gear 14) is Ι ₁ , and the moment of inertia of the sun gear 22, the shaft 24 and the crank pulley 25 when the crank pulley 25 is used as a main inertia mass body, that is, as a sub flywheel is I ₂ , or Pulley 25
When the auxiliary machine is driven to use the rotating body of the auxiliary machine as an inertial mass body, the inertia moment of the sun gear 22, the shaft 24, the crank pulley 25, and the auxiliary machine is I ₂ , and the sun gear 22 with respect to the internal gear 14 is increased. Assuming that the speed ratio is ρ,
The equation of motion related to the roll vibration of the engine body is expressed by the following equation (1).

[0042] As understood from the above equation (1), as the coefficient (Ι ₁ −ρ · Ι ₂ ) / (Ι ₁ + ρ ² · _{２ 2} ) applied to T on the right side approaches 0, the reduction in roll vibration increases. Become. That is, the following equation (2), so as to satisfy the _{Ι 1 = ρ · Ι 2 ···} (2), with respect to the moment of inertia iota ₁ of the engine body rotation system, the pitch of the internal gear 14 and sun gear 22 radius R _i, R _s, the sun gear 22, a crank pulley 25, shaft 24, or, if further auxiliary setting the overall moment of inertia iota ₂ plus, a reduction in rolling vibration becomes the largest.

Incidentally, the above-described roll vibration reduction effect is as follows.
When all components can be treated as rigid bodies, they are always constant regardless of the operating conditions of the engine.However, since the components are actually elastic, a resonance phenomenon occurs in the vibration system composed of these components. I do. A representative example of the resonance phenomenon is a resonance vibration of a torsional vibration system in which the torsional rigidity of the shaft 24 is a spring component and the moment of inertia of the crank pulley 25 is a mass component in the configuration from the sun gear 22 to the crank pulley 25.

Here, in the torsional vibration system, the moment of inertia of the crank pulley 25 is represented by I _f ,
Assuming that the torsional spring constant is κ, the equation of motion of linear free vibration when the shaft 24 is twisted by the angle θ from the equilibrium position is expressed by the following equation (3).

[0045] Therefore, the natural frequency Wn in this vibration system is given by the following equation (4). When the shaft 24 is a solid round bar, the shear modulus of elasticity is G, the axial length of the shaft 24 as a connecting portion between the sun gear 22 and the crank pulley 25 is L, and the shaft length is L. 24, the secondary moment of area is I
_Assuming that _p , the natural frequency Wn can be expressed by the following equation (5). Furthermore, since fn = Wn / 2π, the resonance frequency (natural frequency) fn can be expressed by the following equation (6).

[0046] The influence of the resonance phenomenon of the torsional vibration system on the roll vibration of the engine will be described below with reference to FIG. 5A is an amplitude ratio characteristic between engine torque fluctuation and cancel torque, FIG. 5B is a phase difference characteristic between engine torque fluctuation and cancel torque, and FIG. 5C is a dominant roll vibration frequency. 7 shows the roll vibration characteristics of the engine according to the f component (a secondary component of the engine rotational speed in the case of an in-line four-cylinder engine, and a tertiary component of the engine rotational speed in the case of an in-line six-cylinder engine).

As can be seen from FIG. 5A, when the frequency of the torsional vibration is low, the amplitude ratio between the two is almost constant, but as the frequency of the torsional vibration approaches the resonance frequency (fn), the amplitude of the canceling torque increases. the amplified, P ₁ the amplitude of the cancellation torque is the same as the amplitude of the torque variation
When the frequency exceeds the frequency fo at the point, the amplitude of the cancel torque becomes larger than the amplitude of the torque fluctuation, and the amplification degree becomes P
It is maximum at _two points, that is, at the position of the resonance frequency fn.

Further, as can be seen from FIG. 5B, the phases of the two, which were opposite in the low frequency region, are changed to the resonance frequency fn.
In the vicinity, it is in phase and acts in the direction to increase the roll vibration of the engine.

Further, in an engine equipped with an actual roll vibration reducing device, as shown in FIG. 5C, a constant roll vibration reducing effect is obtained in a region where the engine rotation speed (or frequency) is low. although the amplitude of the cancel torque amplitude and maximum roll vibration reduction effect at the location of the same on becomes P ₁ point of the torque fluctuation obtained in the rotational speed region in excess of the P ₁ point in the roll vibration deteriorates conversely You can see that

As described above, in the coupling between the crank pulley 25, the shaft 24, and the sun gear 22 in the present embodiment, the resonance frequency fn is higher than the dominant roll vibration frequency f at the maximum rotation speed of the engine. It is constituted so that it may become. With such a coupling configuration, a desired roll vibration reduction effect can be obtained without causing deterioration of the roll vibration due to torsional vibration in a practical operation region of the engine.

When the resonance frequency fn is equal to the dominant roll vibration frequency f at the maximum engine speed, the roll vibration deteriorates near the upper limit of the engine rotation. Since the frequency of use of the region is very low, there is no practical problem with such a configuration.

[0052] Moreover, it is taken with the increase of the frequency of the torsional vibration is amplified amplitude of the cancellation torque, since it becomes the same as the amplitude of the torque variation at the position of P ₁ point, the torsional vibration at this position Using the frequency fo as one guide,
The crank pulley 25, the shaft 24, and the sun gear 22 may be connected to each other such that the torsional vibration frequency fo is higher than the dominant roll vibration frequency f at the maximum rotation speed of the engine.

By adopting such a coupling configuration, a desired effect of reducing the roll vibration can be reliably obtained in the entire operation range of the engine without causing deterioration of the roll vibration due to the torsional vibration. Empirically, by setting the torsional resonance frequency fn to be about 1.2 times the dominant roll vibration frequency f, it is possible to reduce the desired roll vibration in the entire operation range of the engine without deteriorating the roll vibration. The effect of reducing the roll vibration can be obtained.

By the way, in actually designing the above coupling structure, the dominant roll vibration frequency f at the maximum rotational speed of the engine is calculated by the following equation (6) using the above-mentioned equation (6) representing the resonance frequency fn of torsional vibration. 7), Can be set to satisfy.

According to this, the resonance frequency fn of the torsional vibration can be deviated from the practical operation range of the engine in advance from the design stage by the desk calculation.

In the above-described embodiment, the type in which an auxiliary machine is rotated by the crank pulley 25 to generate a cancel torque has been described. Instead of the crank pulley 25, an auxiliary flywheel as an inertial mass body is employed. Then, it is also possible to adopt a configuration in which a cancel torque is generated by this sub flywheel, in which case, the sub flywheel and the sun gear are integrally formed,
Alternatively, it is also possible to adopt a shaft connecting the sub flywheel and the sun gear, and to integrally form any two or all of the sub flywheel, the shaft and the sun gear.

[Brief description of the drawings]

FIG. 1 is a first view of a vibration reduction device for an internal combustion engine according to the present invention.
It is a schematic structure figure showing an example of.

[2] The sun gear in the embodiment shown in FIG. 1, which shows the shaft, and a coupling relation between the crank pulley mutual, E ₁ of (a) a partially enlarged cross-sectional view, the (b) is (a)
-E is a sectional view taken along the ₁ and _E 2 -E ₂ parts.

FIGS. 3A and 3B show another example of the rotational movement restraining means, in which FIG. 3A is a cross-sectional view showing a key connection, and FIG. 3B is a side view showing a jaw clutch connection, which is one of the meshing clutches.

FIGS. 4A and 4B are diagrams for explaining the operation of the vibration reduction device according to the present invention, wherein FIG. 4A is a schematic diagram showing a force relationship acting on each gear of the planetary gear, and FIG. It is a schematic diagram which shows the force relationship which performs.

5A and 5B are diagrams for explaining the effect of torsional vibration on the roll vibration of the engine, wherein FIG.
(B) is a graph showing a phase difference characteristic between engine torque fluctuation and canceling torque, and (a) is a graph showing roll vibration characteristics with respect to an engine rotation speed.

FIG. 6 is a schematic configuration diagram showing a conventional vibration reduction device.

FIG. 7 is a front view of an engine including a conventional vibration reduction device.

[Explanation of symbols]

 Reference Signs List 10 Vibration reduction device 11 Cylinder block 12 Crankshaft 12a Reduced diameter portion 13 Chain sprocket 14 Internal gear 15 Bolt 16 Washer 17 Front cover 19 Planetary gear 20 Gasket 21 Carrier cover (carrier) 21a Support shaft 21b Stopper piece 22 Sun gear 23 Bearing 24 Shaft 24a Inside large diameter part 24b Outside large diameter part 24c Small diameter part 24c 'Male screw (screw part) 24d Step end face 25 Crank pulley (inertia mass body) 25a Cylindrical part 25b Fitting hole 26 Nut 28 Oil seal 29, 30 Thrust bearing

Claims (9)

[Claims] A planetary gear mechanism including a sun gear, a planetary gear held by a carrier so as to mesh with the sun gear, and an internal gear meshing with the planetary gear; and an inertial force rotated by the operation of the planetary gear mechanism. Wherein the internal gear is fixed to the crankshaft so as to rotate integrally on the same axis as the crankshaft, and the carrier is fixed to prohibit the planetary gear from revolving. The inertial mass body is formed so as to rotate integrally with the sun gear in a direction opposite to a rotation direction of the crankshaft, so as to reduce roll vibration of the internal combustion engine accompanying rotation of the crankshaft. A vibration reducing device for an internal combustion engine, wherein the torsion vibration between the inertial mass body and the sun gear is reduced. The inertial mass and the sun gear are coupled so that a vibration frequency fn is higher than a dominant roll vibration frequency f at the maximum rotation speed of the internal combustion engine. . 2. A planetary gear mechanism including a sun gear, a planetary gear held by a carrier so as to mesh with the sun gear, and an internal gear meshing with the planetary gear, and an inertial force rotated by the operation of the planetary gear mechanism. Wherein the internal gear is fixed to the crankshaft so as to rotate integrally on the same axis as the crankshaft, and the carrier is fixed to prohibit the planetary gear from revolving. The inertial mass body is formed so as to rotate integrally with the sun gear in a direction opposite to a rotation direction of a crankshaft, and generates a cancel torque by the rotating body including the inertial mass body and the sun gear, thereby generating a crank torque. Internal combustion engine vibration to reduce roll vibration of the internal combustion engine due to shaft rotation A dynamic reduction device, wherein the torsional vibration frequency fo when the amplitude of the cancel torque amplified by the torsional vibration between the inertial mass body and the sun gear and the amplitude of the torque fluctuation of the internal combustion engine substantially match each other, The vibration reducing device for an internal combustion engine, wherein the inertial mass body and the sun gear are coupled so as to be higher than a dominant roll vibration frequency f at the maximum rotation speed of the engine. 3. The moment of inertia of the inertial mass body is I _f , the shear modulus of elasticity of the joint between the inertial mass body and the sun gear is G, the secondary polar moment of area of the joint is I _p , When the axial length of the portion is L, the dominant roll vibration frequency f is The vibration reduction device for an internal combustion engine according to claim 1 or 2, wherein the inertial mass body and a sun gear are coupled to satisfy the following. 4. A shaft connecting the inertial mass and the sun gear, wherein the shaft has a small diameter portion and a large diameter portion, and the inertial mass has a relative diameter at a large diameter portion of the shaft. Coupled by a rotational movement restricting means for restricting the rotational movement, and at a small diameter portion of the shaft,
The vibration reduction device for an internal combustion engine according to any one of claims 1 to 3, wherein the shafts are coupled by translational restraint means for restraining relative translational movement in the axial direction. 5. A shaft connecting the inertial mass body and the sun gear, wherein the shaft has a small diameter portion and a large diameter portion, and the sun gear has a relative rotation at a large diameter portion of the shaft. 5. The apparatus according to claim 1, wherein said means is connected by a rotational movement restraining means for restraining the movement.
A vibration reduction device for an internal combustion engine according to any one of the preceding claims. 6. The rotation movement restraining means comprises a spline connection provided between an inner peripheral surface of a cylindrical portion formed on the inertial mass body and an outer peripheral surface of a large diameter portion of the shaft.
The vibration reduction device for an internal combustion engine according to claim 4 or 5, wherein: 7. The method according to claim 7, wherein the rotational movement restricting means comprises a key joint provided between an inner peripheral surface of a cylindrical portion formed on the inertial mass body and an outer peripheral surface of a large diameter portion of the shaft. The vibration reduction device for an internal combustion engine according to claim 4 or 5, wherein: 8. The apparatus according to claim 4, wherein said rotational movement restraining means comprises an engagement clutch provided between a cylindrical portion formed on said inertial mass body and a large diameter portion of said shaft. Or the vibration reduction device for an internal combustion engine according to 5. 9. The small-diameter part and the large-diameter part of the shaft, wherein the small-diameter part and the large-diameter part of the shaft are fitted in a fitting hole formed in a center part of the inertial mass body. 5. The internal combustion engine according to claim 4, further comprising a nut or a bolt that is screwed into a threaded portion formed on a small diameter portion of the shaft so as to press the inertial mass body toward an end surface of the stepped portion. 6. Engine vibration reduction device.