JP3367440B2 - Damper device and driving force transmission device for internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force transmission device for an internal combustion engine equipped with a damper device and a balance device.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine such as an in-vehicle engine, combustion of fuel causes a piston to reciprocate, and the reciprocating movement of the piston is converted into rotation of a crankshaft, which is an output shaft, by a connecting rod to generate a driving force. Trying to get. When the piston reciprocates, an inertial force of the piston is generated in the same moving direction, but it is preferable to bring the inertial force as close to "0" as possible in order to smoothly operate the internal combustion engine.

Therefore, conventionally, a balance device is provided in the internal combustion engine so that the inertial force of the piston approaches "0". This balance device includes a balance shaft extending parallel to the crankshaft of the internal combustion engine. The balance shaft is rotatably supported around its own axis, and a weight (unbalanced mass) is provided on the outer peripheral surface of the balance shaft in an eccentric state with respect to the axis.

By rotating the balance shaft in synchronization with the crankshaft, the inertial force of the weight acts in the moving direction of the piston, and the inertial force of the weight cancels out the inertial force of the piston, and the inertial force " It becomes possible to set it to "0". As described above, in order to reduce the inertial force to “0”, it is necessary to rotate the crankshaft and the balance shaft in synchronization, but the synchronized rotation balances the rotation of the crankshaft through the driving force transmission device. It is realized by transmitting to the shaft.

Japanese Utility Model Laid-Open No. 61-106647 discloses a drive force transmission device shown in FIG. This driving force transmission device includes a disc-shaped holder 92 fixed to a balance shaft 91, and an annular gear 93 that is fitted on the outer peripheral surface of the holder 92 and meshes with a gear (not shown) of a crankshaft. ing. Then, between the outer peripheral surface of the holder 92 and the inner peripheral surface of the gear 93, recesses 92a, 93a are formed at corresponding positions, and the accommodating portion 9 formed by the opposed recesses 92a, 93a.
A damper spring 95 is arranged in the inside of the cylinder 4. A holding plate 96 is fixed to the holder 92 by a rivet 97 to prevent the damper spring 95 from being separated from the housing portion 94. Then, the gear 93 rotates together with the holder 92 via the damper spring 95.

In the driving force transmission device thus constructed, the rotation of the crankshaft is transmitted to the gear 93, and the rotation of the gear 93 is transmitted to the holder 92 and the balance shaft 91 via the damper spring 95. When the crankshaft rotates, a torque fluctuation occurs in the shaft in the rotation direction.
When the rotation is transmitted from 3 to the holder 92, the damper spring 9
5 expands and contracts to absorb. Therefore, the torque fluctuation of the crankshaft is prevented from being transmitted to the balance shaft 91 of the balance device.

Further, Japanese Utility Model Laid-Open No. 59-42335 discloses an anti-torque balancer equipped with a rotor having a large moment of inertia that rotates in a direction opposite to the rotational direction of the engine, and driven wheels driven by the engine and An anti-torque balancer is disclosed in which a rubber buffer member is interposed between a rotating body and a driven shaft, and a clutch mechanism is provided to directly drive the driven wheel and the driven shaft at a predetermined rotation speed or less.

[0008]

[Problems to be Solved by the Invention]
By transmitting the rotation of the crankshaft to the balance shaft 91 using the driving force transmission device described in Japanese Patent Publication No. 47, it is possible to prevent torque fluctuations of the crankshaft from being transmitted to the balance device side.

However, since a member for restricting the relative rotation between the holder 92 and the gear 93 is not provided in particular,
When a large torque acts on the gear 93, the holder 92
The gear 93 and the gear 93 rotate relative to each other until the coil of the damper spring 95 comes into close contact with each other, and then the relative rotation is restricted so that the two rotate integrally. In such a state, the end portion of the damper spring 95 is in a state of strongly abutting on the inner surfaces of the recesses 92a and 93a that define the housing portion 94, and the inner surface is worn and the strength of the gear 93 is reduced.
In addition, a state in which a force exceeding the elastic limit is applied to the damper spring 95, and such contraction is repeated, the damper spring 95 deteriorates early.

Although it is possible to prevent the damper spring 95 from contracting to the elastic limit by lengthening the damper spring 95 to widen the range of relative rotation, it is necessary to enlarge the accommodating portion 94, and the holder 92 and the gear. In order to maintain the strength of 93, it is necessary to make the holder 92 and the gear 93 large, and the increase in the size of the holder 92 and the gear 93 due to the increase in the radial thickness thereof cannot be ignored.

The counter torque balancer disclosed in Japanese Utility Model Laid-Open No. 59-42335 discloses that a clutch mechanism for directly driving the driven wheel and the driven shaft at a predetermined rotational speed or less is provided. However, this clutch mechanism prevents the damper mechanism from operating when the engine rotates at a low speed, and even if this mechanism is applied to a driving force transmission device, the holder 92 and the gear are operated while the damper mechanism is operating. The relative rotation of 93 cannot be restricted below a predetermined amount.

Further, in the conventional damper mechanism, since the damper spring is arranged at the point symmetrical position, the damper mechanism does not play a part of the role of the unbalance mass of the balance shaft.

The present invention has been made in view of the above circumstances, and a first object thereof is to prevent early deterioration of a damper spring and, when applied to a balance device, provide the balance shaft. An object of the present invention is to provide a damper device that can reduce the unbalance mass. A second object of the present invention is to provide a driving force transmission device for an internal combustion engine which can reduce the size of the balance device and prevent early deterioration of the damper spring.

[0014]

In order to achieve the above-mentioned first object, in the invention described in claim 1, the first spring holder and the relative rotation relative to the first spring holder are coaxial. A second spring holder that is movably disposed, and a damper spring that is provided between the first and second spring holders and that transmits the rotational force of one spring holder to the other spring holder between the spring holders. A regulating portion that is provided between the spring holders and that regulates relative rotation of the spring holders in a contracting direction of the damper spring by a predetermined amount or more, and the center of gravity of the regulating portion and the damper spring as a whole is the same. The position and weight of the restriction portion were set so as to be biased with respect to the rotation center of the holder.

In order to achieve the above-mentioned second object, claim 2
According to another aspect of the present invention, there is provided a driving force transmission device for an internal combustion engine, comprising a balance device for canceling out inertial force of a piston acting on a crankshaft, the device being located on the same axis and rotatable about a coaxial line. A first and a second driving force transmitting member, and a cushioning mechanism for connecting the first and the second driving force transmitting members to each other in the rotation direction thereof, and the rotation of the first driving force transmitting member is described above. The first and second drive units have a restriction portion that transmits the force to the second driving force transmission member via a damper spring provided in the shock absorbing mechanism and restricts the shock absorbing mechanism from contracting more than a predetermined amount of the damper spring. The regulating portion is arranged between the transmission members, and is arranged at a position where it can play a part of the role of the unbalanced mass provided on the balance shaft of the balance device.

According to a third aspect of the present invention, in the second aspect of the invention, the damper device according to the first aspect is used as the buffer mechanism, and the first and second damper devices are provided.
One of the spring holders was attached to one of the first and second driving force transmitting members, and the other spring holder was attached to the other driving force transmitting member.

According to a fourth aspect of the invention, in the third aspect of the invention, the first driving force transmitting member is attached to the balance shaft so as to be rotatable relative to the balance shaft, and the second driving force transmitting member is The balance spring is integrally rotatably provided, the first spring holder is fixed to the first driving force transmitting member, and the second spring holder is fixed to the second driving force transmitting member. .

In the damper device according to the first aspect of the invention, both spring holders are coaxially arranged so as to be rotatable relative to each other. The rotational force of one spring holder is transmitted to the other spring holder via the damper spring. The damper spring is contracted when the rotational force is transmitted. If there is no restricting part that restricts the relative rotation of both spring holders, if the compressive force acting on the damper spring is large, the relative movement of both spring holders will occur when the damper spring contracts to a state where it cannot be further contracted. The rotation is stopped. In that state, a force exceeding the elastic limit acts on the damper spring, and if such contraction is repeated, the damper spring deteriorates early. Also, the wear of the holder becomes faster. However, due to the presence of the restricting portion, both spring holders restrict the relative rotation of the damper springs in the contracting direction when the damper springs contract to a predetermined amount. As a result, early deterioration of the damper spring is suppressed, and early wear of each spring holder is also suppressed. Further, since the position and weight of the restricting portion are set so that the center of gravity of the restricting portion and each damper spring as a whole is offset with respect to the rotation axis of the holders, the damper device of the present invention can be used to balance the internal combustion engine. When used in a device, the unbalanced mass provided on the balance shaft can be reduced.

According to the second aspect of the invention, when the rotation of the first driving force transmitting member is transmitted to the second driving force transmitting member via the damper spring, the damper spring contracts. When the amount of contraction of the damper spring becomes a predetermined amount or more, an excessive force is applied to the damper spring, causing early deterioration of the damper spring and early wear of the contact portion with the damper spring. However, due to the presence of the restricting portion, the damper spring is restricted from contracting by a predetermined amount or more, and the inconvenience is avoided. Moreover, since the regulating portion plays a part of the role of the unbalanced mass provided on the balance shaft of the balancing device, the unbalanced mass can be reduced.

According to a third aspect of the present invention, in the second aspect of the invention, the damper device according to the first aspect is used for the cushioning mechanism. According to a fourth aspect of the invention, in the third aspect of the invention, the second driving force transmitting member rotates integrally with the balance shaft. The first driving force transmitting member is rotatable relative to the balance shaft, and the rotation of the first driving force transmitting member transmits the second driving force via the first spring holder, the damper spring, and the second spring holder. Transmitted to the member.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a balance device for an automobile engine will be described below with reference to FIGS.

As shown in FIG. 3, the crankshaft 11, which is the output shaft of the engine, is rotatably supported around the axis of the crankshaft 11 at the lower end of the cylinder block 12 of the engine. A piston (both not shown) is connected to the crankshaft 11 via a connecting rod. When the engine is operating, the reciprocating movement of the piston in the vertical direction in the drawing is converted into rotation of the crankshaft 11 by the connecting rod. In addition, the crankshaft 11 has a helical tooth 13
A metal crankshaft gear 13 having a is fixed to the shaft 11 so as to rotate integrally therewith.

At the lower end of the cylinder block 12, there is attached a balance device 14 for canceling out the inertial force of the piston acting in the moving direction of the piston when the engine is operating. The balance device 14 includes a pair of housings 1.
First and second balance shafts rotatably supported between 5a and 15b in parallel with the crankshaft 11 (only the first balance shaft is shown in FIG. 3) 16,1
Equipped with 7. An unbalance mass 18 is provided on each of the first and second balance shafts 16 and 17 in a state of being eccentric to the axis of the shaft 16 or 17.

First and second balance shafts 16 and 1
The rotation of the crankshaft 11 is transmitted to the motor 7 via the crankshaft gear 13 and the driving force transmission device 19. When the rotation of the crankshaft 11 is transmitted to the first and second balance shafts 16 and 17, the shafts 11, 16 and 17 rotate in synchronization with each other. Then, the first and second balance shafts 1
When the shafts 6 and 17 rotate, the unbalanced mass 18 rotates together with the shafts 16 and 17 and reciprocates in the moving direction of the piston (vertical direction in the drawing).

Therefore, the unbalanced mass 18 is reciprocally displaced by the synchronized rotation of the crankshaft 11 and the first and second balance shafts 16 and 17, and the inertial force of the unbalanced mass 18 is changed in the moving direction of the piston ( It works in the vertical direction in the figure). The mass of the unbalanced mass 18, the mounting positions of the shafts 16 and 17 in the circumferential direction, and the like are adjusted in advance so that the inertial force of the unbalanced mass 18 and the inertial force of the piston cancel each other out to become "0". ing.

Next, the detailed structure of the driving force transmission device 19 and the damper device incorporated in the driving force transmission device 19 will be described. As shown in FIGS. 1, 3 and 4, the driving force transmission device 19 controls the rotation of the crankshaft 11 to the first
Gear mechanism 20 for transmitting to the balance shaft 16 of the
Is equipped with. The gear mechanism 20 is a buffer that connects first and second gears 21 and 22 arranged in parallel on the axis of the first balance shaft 16 and the gears 21 and 22 in the rotation direction about the axis. The damper device 23 as a mechanism is provided.

The first gear 21 as a first driving force transmitting member is attached to the first balance shaft 16 so as to be rotatable relative to it, and has oblique teeth 21a meshing with the oblique teeth 13a of the crankshaft gear 13 on its outer peripheral portion. Have A plurality of fitting holes 21b are formed in the first gear.

The second gear 22 as the second driving force transmitting member has oblique teeth 22a on the outer peripheral portion thereof and is integrally rotatably provided on the first balance shaft 16. In the present embodiment, the second gear 22 is formed integrally with the first balance shaft 16. On the surface of the second gear 22 facing the first gear 21, a cylindrical housing portion 24 having a step is formed. The accommodation portion 24 is formed to have a large diameter on the side close to the first gear 21.

The damper device 23 includes a first spring holder 25, a second spring holder 26, and a damper for transmitting the rotational force of one spring holder 25 between the two spring holders 25, 26 to the other spring holder 26. And a spring 27.

As shown in FIG. 5, the first spring holder 25 is formed in a cylindrical shape with a bottom, and a hole 25b into which the first balance shaft 16 can be loosely inserted is formed at the center of the bottom wall 25a. The first spring holder 25 includes the peripheral wall 25.
The height of c is formed to be substantially the same as the outer diameter of the damper spring 27, and four protrusions 29 projecting toward the center of the spring holder 25 are provided inside at equal intervals in the circumferential direction. . Each protrusion 29 is formed in a substantially isosceles right triangle shape, and is arranged such that the hypotenuse side faces the outside of the first spring holder 25 so that the faces of the adjacent protrusions 29 that face each other are parallel to each other. Is formed in. Then, as shown in FIG. 2, the damper spring 27 is accommodated between the end surfaces 29a of the projecting portion 29 which face each other. Further, each protrusion 29 is formed with an arc-shaped guide groove 29b having the center of the first spring holder 25 as the center.

As shown in FIGS. 1 and 5, a fitting hole 30 corresponding to the fitting hole 21b of the first gear 21 is formed in the bottom wall 25a of the first spring holder 25. First
In the spring holder 25, the fixing pin 31 fitted and fixed in the fitting holes 21b and 30 in a state where the bottom wall 25a abuts on the surface of the first gear 21 facing the second gear 22,
Relatively rotatable with respect to the first balance shaft 16,
It is fixed to the first gear 21 so as to be integrally rotatable.

As shown in FIG. 5, the second spring holder 26 has a ring-shaped plate 32 and a pair of locking members projecting from the surface of the plate 32 facing the first spring holder 25. It is composed of a piece 33 and a locking piece 35 having a stopper 34 that constitutes a restriction portion at the center. The locking pieces 33, 35 are formed in an arc shape having the same curvature as the guide groove 29b of the protrusion 29, and are formed at positions corresponding to the guide groove 29b. Then, as shown in FIGS. 1 and 2, in the second spring holder 26, the plate 32 is accommodated in the small-diameter portion of the accommodating portion 24, and the locking pieces 33, 35 are loosely inserted in the guide groove 29b. , Is integrally rotatably fixed to the second gear 22 by fixing means (not shown).

The second spring holder 26 is different from the first spring holder 25 in that
The first balance shaft 16 is integrally rotatably fixed to the first balance shaft 16 and is coaxially rotatable relative to the first balance shaft 16. Then, the second spring holder 26 serves as the stopper 3
4 is the first position up to the position where the end face 4a of the protrusion 29 comes into contact with
When the stopper 34 is in contact with the end surface 29a, relative rotation of the damper spring 27 in the contracting direction is restricted. In the present embodiment, the stopper 28 and the end surface 29a with which the stopper 34 abuts constitute the restriction portion 28. That is, the restricting portion 28 is configured so that the spring holders 25, 2 having a predetermined amount or more in the contracting direction of the damper spring 27 have a predetermined amount or more.
The relative rotation of 6 is restricted.

The damper spring 27 is composed of a linear coil spring, and is provided between the spring holders 25 and 26. As shown in FIG. 2, in the damper spring 27, both ends of the damper spring 27 are in contact with both end surfaces 29 a of the protrusion 29 and the locking pieces 33, 35 when the rotational force is not acting on the first spring holder 25. The end faces 33a and 35a are held in a engaged state. Three damper springs 27 are provided, and are arranged symmetrically with respect to a straight line passing through the centers of the damper spring 27 and the stopper 34 arranged in the center. Also,
The position and the weight of the stopper 34 are set so that the center of gravity of the stopper 34 and the damper spring 27 as a whole is deviated from the center of rotation of the spring holders 25 and 26. Then, the second spring holder 26 is arranged such that the stopper 34 is arranged at a position where it can play a part of the role of the unbalance mass 18 provided on the first balance shaft 16. It is fixed to. In the present embodiment, the stopper 34 is the first balance shaft 1
The second spring holder 26 is located at a position corresponding to the bulging side of the unbalanced mass 18 provided in FIG.
Are fixed to the second gear 22.

The gear mechanism 20 constructed as described above is
The first gear 21 meshes with the crankshaft gear 13 attached to the crankshaft 11, and the second gear 22 meshes with the third gear 36 as shown in FIG. The third gear 36 is integrally rotatably fixed to a second balance shaft 17 provided in parallel with the first balance shaft 16. In the present embodiment, the driving force transmission device 19 is composed of the third gear 36 and the gear mechanism 22.

Next, the operation of the driving force transmission device 19 configured as described above will be described. When the crankshaft 11 rotates due to the reciprocating movement of the piston, the rotation of the shaft 11 is transmitted to the first gear 21 of the gear mechanism 20 in the driving force transmission device 19 via the crankshaft gear 13. The rotation transmission from the crankshaft gear 13 to the first gear 21 causes the first gear 21 to rotate with respect to the first balance shaft 16 about the axis of the shaft 16. Further, when the first gear 21 rotates, the rotation is transmitted to the second gear 22 and the third gear 36 via the damper device 23 in the gear mechanism 20. Then, the crankshaft 11 and the first and second balance shafts 1
Since 6 and 17 rotate in synchronization, the inertial force of the piston is canceled by the inertial force of the unbalanced mass 18.

When the rotation of the first gear 21 is transmitted to the second gear 22 via the damper device 23, both gears 21,
22 relatively rotates, and both spring holders 25 and 26 also relatively rotate around the axis of the first balance shaft 16. Then, the distance between the end surface 29a of the protrusion 29 on the rotation direction side of the first spring holder 25 and the end surfaces 33a, 35a of the locking pieces 33, 35 facing the end surface 29a is shortened. As a result, each damper spring 27 is compressed.

Crankshaft 1 by reciprocating piston
In the case of one rotation, the torque of the shaft 11 causes torque fluctuation. However, even if the torque change causes the first gear 21 to change in the relative rotation direction with respect to the second gear 22, the damper spring 27 expands and contracts to cause relative rotation in the first gear 21. The fluctuation in the direction is not transmitted to the second gear 22.

Further, the expansion and contraction of the damper spring 27 also plays a role of absorbing the shock when the rotation is transmitted from the crankshaft gear 13 to the first gear 21. That is, the impact applied from the crankshaft gear 13 to the first gear 21 during the transmission of the rotation is alleviated by the expansion and contraction of the damper spring 27.

When the damper spring 27 is compressed,
When there is no restricting portion 28 that restricts the relative rotation of the spring holders 25 and 26, when the compressive force acting on the damper spring 27 is large, the damper spring 27 contracts to a state where it cannot be further contracted. Thus, the relative rotation of both spring holders 25 and 26 is stopped. In that state, a force exceeding the elastic limit acts on the damper spring 27, and if such contraction is repeated, the damper spring 2
7 deteriorates early. In addition, both spring holders 25,
The wear of 26 also becomes faster.

However, due to the existence of the restricting portion 28, in both spring holders 25 and 26, the stopper 34 becomes the end surface 29a of the projection 29 when the damper spring 27 contracts to a predetermined amount as shown in FIG. The damper spring 27 abuts and the relative rotation of the damper spring 27 in the contracting direction is restricted.
As a result, early deterioration of the damper spring 27 is suppressed, and also early wear of both spring holders 25, 26 is suppressed.

In addition, the center of gravity of the restricting portion 28 and each damper spring 27 is deviated from the axial center of the first balance shaft 16, and the restricting portion 28 plays a part of the role of the unbalance mass 18. Since it is provided, the unbalanced mass 18 can be reduced accordingly. Specifically, the dimension L of the unbalanced mass 18 in FIG. 1 can be shortened.

According to this embodiment described in detail above, the following effects can be obtained. (1) The first and second spring holders 25, 26 holding the damper spring 27 of the damper device 23 are restricted from rotating relative to the contraction direction of the damper spring 27 by a predetermined amount or more by the action of the restricting portion 28. To be done. Therefore, it is possible to prevent a force exceeding the elastic limit from acting on the damper spring 27, and prevent the damper spring 27 from being deteriorated early or both spring holders 25 and 26 from being worn early.

(2) The center of gravity of the restricting portion 28 of the damper device 23 and the damper spring 27 is constructed so as to deviate from the axial center of the first balance shaft 16, and the restricting portion 28 of the unbalanced mass 18 is arranged. Since it is provided at a position that plays a part of the role, unbalanced mass 1
8 can be reduced. As a result, the balance device 14 can be downsized.

(3) Since the damper device 23 independently constitutes one unit, by incorporating the damper device 23 into the gear mechanism 20 of the power transmission device 19, the effects of the above (1) and (2) are obtained. And can be easily applied to existing balance devices.

(4) Most of the portion of the regulating portion 28 that plays a part of the role of the unbalance mass 18 (the stopper 3
4) the second fixed to the first balance shaft 16 side
It is provided on the spring holder 26. Therefore, it becomes easy to set the mounting position of the restriction portion 18 of the damper device 23.

(5) Since the damper spring 27 of the damper device 23 is not arranged between the circumferential surfaces of the spring holders 25 and 26 but between the surfaces facing each other in the axial direction, the damper spring 27 has the same length. When the damper spring 27 is used, the outer diameter of the spring holder can be reduced.
Therefore, the balancer 14 can be made smaller.

The embodiment is not limited to the above, but may be modified as follows, for example. -Instead of collectively providing the unbalance masses 18 at one place, as shown in FIG. 7, the unbalanced masses 18 may be provided separately on both sides of the gear mechanism 20.

The second gear 22 or the unbalanced mass 18 is formed separately from the first balance shaft 16.
It may be integrally rotatably fixed to the first balance shaft 16. In this case, the processing of the first balance shaft 16 and the second gear 22 is simplified.

As shown in FIG. 8, the outside of the damper spring 27 is attached to the end portions of the locking pieces 33 and 35 on the side that acts to press the damper spring 27 when the first balance shaft 16 rotates. Square-shaped engaging portions 33b and 35b having sides with a length equal to or larger than the diameter are provided. In addition, the protrusion 29 is formed with a recess that uses an engaging portion. In this case, one end of the damper spring 27 can always abut the engaging portions 33b and 35b in a stable state.
The damper action by 7 becomes stable.

The second spring holder 26 may be made of a material having a density higher than that of the unbalanced mass 18.
Further, instead of forming all the second spring holders 26 with the same material, the side corresponding to the stopper 34 and the locking piece 35 is formed with a material having a higher density than the unbalanced mass 18, and the other parts are formed with the unbalanced mass. It is formed of a material having a density smaller than 18. In these cases, compared to the case where the entire second spring holder 26 is made of a material having the same density as that of the unbalanced mass 18, the stopper 34 or the like can play a larger role in the unbalanced mass 18. 18 can be made smaller.

The first spring holder 25 may be formed integrally with the first gear 21, or the second spring holder 2
6 may be formed integrally with the second gear 22. In this case, the spring holders 25 and 26 are connected to the gears 21 and 22 respectively.
It eliminates the need for assembling on.

In this embodiment, the damper device 23 is provided with the three damper springs 27, but the number of the damper springs 27 is, for example, two.
The number may be changed to one or one. In this case, the number and shape of the protrusions 29 and the number and shapes of the locking pieces 33 and 35 are changed according to the number of the damper springs 27. In any case, the damper spring 27 is arranged at a position symmetrical with respect to a straight line passing through the center of the stopper 34 and the center of the shaft on which the damper device 23 is attached. If the number of damper springs 27 is reduced, the assembly work becomes easier.

As the damper spring 27, instead of the linear coil spring, a coil spring curved with substantially the same curvature as the locking pieces 33, 35 may be used. In this case, the end surface 29a of the protrusion 29 that holds the damper spring 27 and the end surfaces 33a and 35a of the locking pieces 33 and 35 are formed so as to be located on a plane that passes through the centers of the spring holders 25 and 26. According to this structure, the posture of the damper spring 27 is stabilized when the damper spring 27 expands and contracts due to the relative rotation of the both spring holders 25 and 26.

In place of the structure in which the damper spring 27 is arranged between the surfaces of the spring holders 25, 26 that face each other in the axial direction, both spring holders 25, 26 have the same structure as the damper device disclosed in Japanese Utility Model Laid-Open No. 61-106647. Holder 2
It may be arranged between the peripheral surfaces of 5, 26.

The damper device 23 to the crankshaft 11
May be attached to. For example, crankshaft gear 1
3 is arranged near the end of the crankshaft 11, and the first spring holder 25 of the damper device 23 is fixed to the crankshaft gear 13. A gear is rotatably supported on the crankshaft 11, and the second spring holder 26 is fixed to the gear. Then, the gear is meshed with the gear fixed to the balance shaft 16.

In the present embodiment, the balance device 14 provided with the two balance shafts 16 and 17 is exemplified, but
The number of balance shafts may be appropriately changed to one or three or more according to the number of cylinders of the engine.

In the present embodiment, the gears 21, 22, 36 are exemplified as the driving force transmitting member, but instead of this, a sprocket, a pulley or the like may be adopted as the driving force transmitting member. In these cases, the rotation is transmitted not through the meshing of gears but through the chain or the belt.

In the present embodiment, the damper device 23 is applied to the balance device 14 of the engine driving force transmission device 19, but the damper may be applied to other devices. Also,
The engine is not limited to the engine for automobiles, but may be applied to other engines for ships and the like.

The technical ideas other than those described in the claims that can be understood from the above-described embodiments will be described below along with their effects. (1) In the invention according to any one of claims 2 to 4, the restriction portion is formed of a material having a density higher than that of the unbalanced mass. In this case, it is possible to further reduce the size of the unbalanced mass.

[0061]

As described above in detail, according to the invention as set forth in claim 1, it is possible to prevent the damper spring from prematurely deteriorating, and when applied to the balance device,
The unbalanced mass provided on the balance shaft can be reduced.

According to the invention described in claims 2 to 4, it is possible to reduce the size of the balance device and prevent early deterioration of the damper spring. According to the invention described in claim 3, it can be easily applied to the existing balance device.

According to the fourth aspect of the invention, the setting of the mounting position of the regulating portion of the damper device is simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a driving force transmission device according to an embodiment.

FIG. 2 is a cross-sectional view in which a gear taken along line AA of FIG. 1 is omitted.

FIG. 3 is a schematic side view showing an engine including a driving force transmission device.

FIG. 4 is a schematic front view showing a connection mode between a crankshaft and a balance device.

FIG. 5 is an exploded perspective view of a damper device.

FIG. 6 is a cross-sectional view showing a state where both balance holders are relatively rotated.

FIG. 7 is a cross-sectional view corresponding to FIG. 1 of another embodiment.

FIG. 8 is a sectional view corresponding to FIG. 6 of another embodiment.

FIG. 9 is a partially cutaway front view showing a conventional example of a driving force transmission device.

[Explanation of symbols]

11 ... Crank shaft, 14 ... Balance device, 16 ...
1st balance shaft, 18 ... unbalanced mass, 1
9 ... Driving force transmission device, 21 ... 1st gear as a 1st driving force transmission member, 22 ... 2nd gear as a 2nd driving force transmission member, 23 ... Damper device as a buffer mechanism, 25
... 1st spring holder, 26 ... 2nd spring holder, 27 ... Damper spring, 28 ... Regulation part, 34 ...
Stopper that constitutes the regulation part.

Claims (4)

(57) [Claims] 1. A first spring holder, a second spring holder coaxially rotatably disposed with respect to the first spring holder, and the first and second spring holders. A damper spring provided between the spring holders for transmitting the rotational force of one spring holder to the other spring holder, and both holders provided between the spring holders and having a predetermined amount or more in the contracting direction of the damper springs. And a restriction portion that restricts relative rotation of the holder, and the position and weight of the restriction portion are set so that the center of gravity of the entire restriction portion and the damper spring is biased with respect to the center of rotation of the holders. Damper device. 2. A drive force transmission device for an internal combustion engine, comprising a balance device for canceling out inertial force of a piston acting on a crankshaft, the drive force transmitting device being located on the same axis and rotatable about a coaxial line. A first and a second driving force transmitting member and a buffer mechanism for connecting the first and the second driving force transmitting members to each other in a rotation direction thereof are provided, and the rotation of the first driving force transmitting member is buffered. The first and second drive transmissions are provided to the cushioning mechanism through a damper spring provided in the mechanism, and a restriction portion that restricts the damper spring from contracting by a predetermined amount or more. It is arranged between the members, and the restriction portion is provided at a position capable of playing a part of the role of an unbalanced mass provided on the balance shaft of the balance device. The internal combustion engine of the driving force transmission apparatus. 3. The damper device according to claim 1 is used as the cushioning mechanism, and one of the first and second spring holders of the damper device is attached to one of the first and second driving force transmission members. The driving force transmission device for an internal combustion engine according to claim 2, wherein the other spring holder is attached to the other driving force transmission member. 4. The first driving force transmitting member is rotatably attached to the balance shaft, and the second driving force transmitting member is integrally rotatably provided on the balance shaft. The drive force transmission device for an internal combustion engine according to claim 3, wherein the holder is fixed to the first drive force transmission member, and the second spring holder is fixed to the second drive force transmission member.