JP2002364731A - Damper structure of power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper structure of a power transmission system realizing a suitable damper function by a friction member or a damping force generation means while abrasion and partial abrasion are suppressed. SOLUTION: In this damper structure, a crankshaft is provided with a crank gear. A first balance shaft 30 is provided with a first driven gear 31 permitted to rotate relatively to the shaft 30, meshing with the crank gear. An annular space is formed between the shaft 30 and the first driven gear 31. In the annular space, a fixed part 57a of a friction damper 57 is fixed to the first driven gear 31, while a slide contact part 57b of an elastic material of the damper 57 is provided such that the slide contact part 57b slidingly contacts with the first balance shaft 30. In the annular space, a coil spring 58 formed in an annular shape is provided such that the slide contact part 57b is sandwiched between the coil spring 58 and the first balance shaft 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper structure of a power transmission system suitable for application to, for example, a balancer device of an internal combustion engine.

[0002]

2. Description of the Related Art As is well known, in a balancer device for an internal combustion engine, a balance shaft provided with an unbalanced weight is drivingly connected to a crankshaft via a gear mechanism so that the rotational force of the crankshaft is reduced. To be transmitted. When the balance shaft rotates in synchronization with the crankshaft, the inertial force generated due to the reciprocation of the engine piston is canceled by the unbalance weight, so that the vibration of the internal combustion engine is reduced. I have.

[0003] Since the explosive combustion in the internal combustion engine is performed intermittently, the magnitude of the rotational force transmitted from the crankshaft to the balance shaft is not constant but fluctuates constantly.

[0004] In particular, when the engine rotational speed is low, such as during idling of the internal combustion engine, the fluctuations in the above-mentioned rotational force become large because the interval of combustion is long. When the fluctuation of the rotational force increases, vibration occurs in the gear mechanism, particularly in the gear meshing portion, and the vibration easily causes noise and lowers the durability of the gear.

For this reason, a friction damper for suppressing relative rotation between the two shafts is interposed in a transmission path of the torque from the crankshaft to the balance shaft, and the vibration component of the torque is removed by the friction damper. Conventionally, a damper structure or the like for attenuating has been proposed.

Here, in order to effectively attenuate the vibration at the gear meshing portion by using such a friction damper, the frictional force of the friction damper is set to be sufficiently large so that the frictional damper can be used when the engine rotational speed is low. It is necessary to absorb the fluctuation of the rotation force.

However, if the frictional force of the friction damper is simply set to a large value, a large frictional force acts when the engine speed is high, although a large frictional force is not required. It will be unnecessarily worn, and as a result, its durability will be reduced.

Therefore, conventionally, for example, Japanese Unexamined Patent Application Publication No.
As disclosed in JP-A-61-61, there has been proposed a damper structure in which the frictional force by the friction damper is reduced as the engine speed increases. Hereinafter, two types of damper structures described in this publication will be described.

(First Damper Structure) This damper structure is
Basically, as shown in FIG.
0 and a second gear provided on the balance shaft 152 while being meshed with the first gear 151 and allowed to rotate relative to the balance shaft 152. Gear 153 is provided. Also, the balance shaft 152 and the second gear 153
Between them, a friction damper 154 is provided such that its outer peripheral surface 154a is fixed to the second gear 153 and its inner peripheral surface 154b contacts the balance shaft 152. Further, in this damper structure, a C-shaped leaf spring 155 is provided so as to sandwich the friction damper 154 between the spring 155 and the balance shaft 152.

According to such a damper structure, when the engine rotation speed is low, the inner peripheral surface 154b of the friction damper 154 is pressed against the balance shaft 152 by the contraction force of the spring 155. As a result, the friction damper 154 generates a relatively large frictional force. On the other hand,
When the engine rotation speed increases, the contraction force of the spring 155 decreases due to the centrifugal force acting on itself. Thereby, the balance shaft 15 of the friction damper 154 is formed.
2 and the friction damper 15
4 also decreases.

(Second Damper Structure) This damper structure is also
Basically, as shown in FIG.
0 and a first gear 151 connected to the first gear 151.
51 and a second gear 163 provided on the balance shaft 152 while being allowed to rotate relative to the balance shaft 152. However, in this damper structure, the friction damper 164 is provided fixed to the balance shaft 152, and the plurality of pressing members 167 urged in the axial direction of the balance shaft 152 by the spring 166 are connected to the second gear 163.
It is provided in.

According to such a damper structure, when the engine rotational speed is low, the pressing member 167 is pressed by the friction damper 164 by the urging force of the spring 166. As a result, the friction damper 164 generates a relatively large frictional force. On the other hand, when the engine rotation speed increases, the urging force of the spring 166 decreases due to the centrifugal force acting on the pressing member 167. For this reason, the pressing member 167
Moves in a direction away from the balance shaft 152, the pressing force of the pressing member 167 against the friction damper 164 decreases, and, consequently, the friction damper 164.
The frictional force caused by the friction also decreases.

As described above, according to these damper structures, it is possible to suppress unnecessary wear of the friction damper when the engine rotational speed is high, and to attenuate vibration at the gear meshing portion.

[0014]

However, in the first damper structure, the friction damper 154 has the C
Since only the portion in contact with the U-shaped leaf spring 155 is pressed against the balance shaft 152, uneven wear occurs on the friction damper 154.

In the second damper structure, since the pressing member 167 moves in a direction away from the balance shaft 152 as the engine speed increases, the friction damper 164 and the second damper 164 move together with this movement. The pressing member 167 comes into contact with only a specific portion.
At this time, uneven wear also occurs on the friction damper 164.

In any case, if the friction damper is unevenly worn as described above, not only can a desired frictional force not be obtained, but also a decrease in durability thereof cannot be avoided. Not only the balancer device of the internal combustion engine, but also a friction member such as a friction damper that suppresses relative rotation between the two shafts to which the rotational force is transmitted, or a damping force generation that suppresses the relative rotation. In the damper structure of the power transmission system in which the means is provided, such a fact about the wear of the friction member or the damping force generating means is also generally common.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the wear and uneven wear of a friction member or a damping force generating means while suppressing the friction member or the damping force generating means. An object of the present invention is to provide a damper structure of a power transmission system that realizes a preferable damper function.

[0018]

The means for achieving the above object and the effects thereof will be described below. First, according to the first aspect of the present invention, the first gear connected to the first rotating shaft is meshed with the first gear, and the relative rotation between the first gear and the second rotating shaft is allowed. And a second gear provided on the second rotating shaft, wherein the second rotating shaft serves as a damper member between the second rotating shaft and the second gear. A damper structure of a power transmission system provided with a friction member that suppresses relative rotation between the second gear and the second gear by a frictional force, wherein the friction member is disposed between the second rotation shaft and the second gear. The gist is that a frictional force variable member that varies the frictional force of the friction member is provided over the entire circumference in the circumferential direction of the friction member. I do.

According to the above configuration, when the frictional force for suppressing the relative rotation between the second rotating shaft and the second gear is high due to the centrifugal force acting on the variable frictional force member, the rotating speed of the rotating shaft is high. It acts as a smaller force. Therefore, unnecessary rotation of the friction member when the rotation speed of the rotation shaft is high can be suppressed, and the relative rotation between the second rotation shaft and the second gear can be suitably suppressed. . In addition, since the frictional force variable member is provided around the entire circumference of the friction member in the circumferential direction, the frictional force acts as substantially equal force over the entire circumference of the second rotating shaft in the circumferential direction. And uneven wear of the friction member is suppressed. Therefore, a more suitable damper function by the friction member can be realized while suppressing the wear and uneven wear of the friction member.

The invention described in claim 2 is the same as the invention described in claim 1.
In the damper structure of the power transmission system described in the above, the gist is that the frictional force variable member is a coil spring provided so as to sandwich the frictional member with the second rotation shaft.

According to the above configuration, a frictional force is generated between the second rotating shaft and the friction member by the tightening force of the coil spring. In addition, due to the centrifugal force acting on the coil spring, the tightening force acts as a smaller force as the rotation speed of the rotating shaft increases. Therefore, by providing the coil spring, the effect described in claim 1 can be suitably achieved. In addition, since the coil spring can be easily deformed, it can be easily attached.

According to a third aspect of the present invention, a first gear connected to a first rotating shaft and a relative rotation between the first gear and the second rotating shaft meshed with the first gear. Power transmission system comprising a second gear provided on the second rotating shaft while permitting the rotation of the second rotating shaft, wherein the second gear as a damper member is provided between the second rotating shaft and the second gear. A damper structure of a power transmission system provided with a friction member for suppressing relative rotation between the rotating shaft and the second gear by a friction force, comprising a friction force control means for variably controlling a friction force by the friction member. That is the gist.

According to the above configuration, the frictional force of the friction member is set as an optimal force for suppressing the relative rotation between the second rotating shaft and the second gear according to the rotating speed of the rotating shaft. It becomes possible to do. In addition, the frictional force can be set as a force that suitably suppresses the wear and uneven wear of the friction member. Therefore, a more suitable damper function by the friction member can be realized while suppressing the wear and uneven wear of the friction member.

[0024] The invention described in claim 4 is the same as the invention described in claim 3.
Wherein the frictional member is made of an elastic material having at least one wall thereof as one wall of a hydraulic chamber, and the frictional force control means variably controls the hydraulic pressure applied to the hydraulic chamber. It is the gist of what is.

According to the above configuration, by adjusting the hydraulic pressure applied to the hydraulic chamber, the force for urging the friction member forming one wall of the hydraulic chamber toward the outside of the hydraulic chamber, in other words, ,
The frictional force of the friction member can be freely adjusted.

The invention described in claim 5 is the same as the invention described in claim 3.
Wherein the friction member has a magnetic member on a back surface of a sliding surface thereof, and the friction force control means has an electromagnet and variably controls an electromagnetic force applied to the magnetic member. The gist of this is to do

According to the above configuration, by adjusting the electromagnetic force applied to the magnetic member, the force for urging the friction member in the direction of the sliding contact surface, in other words, the friction force of the friction member can be freely adjusted. Will be able to do it.

According to a sixth aspect of the present invention, a first gear connected to a first rotating shaft and a relative rotation between the first gear and the second rotating shaft meshed with the first gear. In a power transmission system including a second gear provided on the second rotating shaft while permitting the rotation of the second rotating shaft between the second rotating shaft and the second gear. And a second gear, wherein the damping force generating means is provided with damping force generating means for generating damping force for suppressing relative rotation between the second gear and the second rotating shaft. And a damping force variable means for varying the damping force of the damping force generating means with respect to the outer circumference of the damping force generating means. The gist is that it is provided over.

According to the above configuration, the damping force for suppressing the relative rotation between the second rotating shaft and the second gear is increased by the centrifugal force acting on the damping force varying means when the rotating speed of the rotating shaft is high. It becomes possible to act as a smaller force. For this reason, while suppressing unnecessary wear of the damping force generating means when the rotation speed of the rotating shaft is high, the second rotating shaft and the second
Relative rotation with the gear can be suitably suppressed. Moreover, since the damping force varying means is provided around the entire circumference of the damping force generating means in the circumferential direction, the damping force acts as a force substantially equal over the entire circumferential direction of the second rotating shaft. It is possible to suppress uneven wear of the damping force generating means. Therefore, a more suitable damper function by the damping force generating means can be realized while suppressing the wear and uneven wear of the damping force generating means.

The invention described in claim 7 is the same as the invention in claim 6
Wherein the damping force variable means is a coil spring provided so as to sandwich the damping force generating means between the damping force generating means and the second rotating shaft. I do.

According to the above configuration, the damping force by the damping force generating means can be determined by the tightening force of the coil spring. In addition, due to the centrifugal force acting on the coil spring, the tightening force acts as a smaller force as the rotation speed of the rotating shaft increases. Therefore, by providing the coil spring, the effect described in claim 6 can be suitably achieved.

According to an eighth aspect of the present invention, a first gear connected to the first rotating shaft and a relative rotation between the first gear and the second rotating shaft meshed with the first gear. In a power transmission system including a second gear provided on the second rotating shaft while permitting the rotation of the second rotating shaft between the second rotating shaft and the second gear. Force control for variably controlling the damping force by the damping force generation means in a damper structure of a power transmission system provided with damping force generation means for generating damping force for suppressing relative rotation between the gear and the second gear The gist is to have means.

[0033] According to the above configuration, the damping force generated by the damping force generating means is adjusted to the optimum force for suppressing the relative rotation between the second rotating shaft and the second gear in accordance with the rotating speed of the rotating shaft. It becomes possible to set as. And this damping force,
It is also possible to set the force to suitably suppress the wear and uneven wear of the damping force generating means. Therefore, a more suitable damper function by the damping force generating means can be realized while suppressing the wear and uneven wear of the damping force generating means.

The invention according to claim 9 is the same as the invention according to claim 8.
Wherein the damping force generating means is formed of an elastic member having at least one wall thereof as one wall of a hydraulic chamber, and the damping force control means varies a hydraulic pressure applied to the hydraulic chamber. The gist is to control.

According to the above configuration, by adjusting the hydraulic pressure applied to the hydraulic chamber, the force for urging the damping force generating means constituting one wall of the hydraulic chamber outwardly of the hydraulic chamber can be varied. Will be able to This makes it possible to freely adjust the damping force by the damping force generating means.

According to a tenth aspect of the present invention, in the damper structure of the power transmission system according to the eighth aspect, the damping force generating means includes a magnetic member, and the damping force control means includes:
The gist is to provide an electromagnet for variably controlling an electromagnetic force applied to the magnetic member.

According to the above configuration, by adjusting the electromagnetic force applied to the magnetic member, the force with which the magnetic member biases the damping force generating means can be made variable. This allows
The damping force generated by the damping force generating means can be freely adjusted.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which a damper structure according to the present invention is applied to a balancer device for an internal combustion engine will be described below with reference to FIGS. I do.

First, an outline of a balancer device to which the present embodiment is applied will be described with reference to FIG. FIG. 1 is a schematic diagram showing the arrangement of each gear of the balancer device.

As shown in FIG. 1, the balancer device includes a crankshaft 20 as an engine output shaft, a first balance shaft 30 provided below the crankshaft 20 in parallel with the crankshaft 20, and a first balance shaft. And two balance shafts 40.

A radial bearing and a thrust bearing (both not shown) are formed in the internal combustion engine, and the balance shafts 30 and 40 are supported by these bearings. Each of the balance shafts 30 and 40 is provided with a pair of unbalance weights 33 and 43, respectively.
A crank gear 21 is provided on the crankshaft 20 so as to be integrally rotatable.

A first driven gear 31 meshed with the crank gear 21 and rotatable relative to the first balance shaft 30 is provided on the first balance shaft 30.
Is provided. The diameter of the first driven gear 31 is set equal to the radius of the crank gear 21.
Further, the first balance shaft 30 is provided with a counter gear 32 which is press-fitted into the first balance shaft 30 and connected so as to be integrally rotatable. The first driven gear 31 is drivingly connected to a counter gear 32 via a damper mechanism 50 described later, while allowing relative rotation.

On the other hand, the second balance shaft 40 has
A second driven gear 41 meshed with the counter gear 32 and connected to the second balance shaft 40 so as to be integrally rotatable is provided.

At the ends of the balance shafts 30, 40, the thrust bearings 35, 40 for restricting the movement of the shafts 30, 40 in the axial direction are located at positions corresponding to the thrust bearings formed in the internal combustion engine. 45 are formed respectively. Each of these thrust bearings 35, 4
In FIG. 5, the recesses 35a, 35a, and 43b are provided in the portion on the side where the center of gravity of the unbalance weights 33, 43 is located (the lower side in FIG. 45a are formed respectively. Similarly, in the counter gear 32 and the second driven gear 41, the portion on the side where the center of gravity of the unbalance weights 33, 43 is located and the balance shafts 30, 4
The concave portion 32 is located on the opposite side with respect to the axis 0.
a and 41a are respectively formed.

The recesses 32a, 35a, 41a, 4
5a, the counter gear 32, the second
The center of gravity of the driven gear 41 and the thrust bearings 35 and 45 move eccentrically to the same side as the center of gravity of the unbalance weights 33 and 43.

Therefore, the counter gear 32, the second driven gear 41, and the thrust bearings 35, 45 rotate together with the balance shafts 30, 40, so that substantially the same function as the unbalance weights 33, 43 is achieved. Can be played. As a result, each of the recesses 3
The unbalance weights 33 and 43 can be reduced in size and weight by the volume of 2a, 35a, 41a and 45a.

Further, as described above, the counter gear 3
2, the second driven gear 41, and each thrust bearing 35, 4
5 is set so as to be shifted from the axis of each of the balance shafts 30, 40, so that each of the balance shafts 3
0,40 at the part 30 which is supported by the internal combustion engine
A whirling force around the axis of each of the shafts 30 and 40 acts on the a and 40a with the rotation of the components 32, 35, 41 and 45.

Therefore, the respective bearing portions 30a and 40a of the respective balance shafts 30 and 40 rotate while being pressed against the bearings provided in the internal combustion engine by the whirling force. As a result, when each of the balance shafts 30 and 40 rotates, each of the shaft support portions 3
The generation of irregular vibrations at 0a and 40a can be suppressed, and the contact noise generated between the portions 30a and 40a and the internal combustion engine can be reduced.

FIG. 2 schematically shows the relationship between each gear and each shaft. With such a configuration of the balancer device of the internal combustion engine, as shown in FIG.
The torque transmitted from the crankshaft 20 is transmitted to the first balance shaft 30 via the crank gear 21, the first driven gear 31, the damper mechanism 50, and the counter gear 32, and from the counter gear 32. A second balance shaft 40 via a second driven gear 41;
Will also be communicated. Note that "m" shown in FIG.
“1”, “m2”, and “m3” are axes of the crankshaft 20, the first balance shaft 30, and the second balance shaft 40, respectively.

Next, the structure of the damper mechanism 50 will be described with reference to FIGS. In addition, these FIGS.
5 is a diagram showing a cross-sectional structure of the damper mechanism 50, FIG. 3 is a cross-sectional structure of the first balance shaft 30 of the damper mechanism 50 in the axial direction, and FIG. FIG. 5 shows a cross-sectional structure taken along line 5-5 in FIG.

As shown in FIG. 3, the first driven gear 31
Is an annular inner peripheral portion 31a provided coaxially with the first balance shaft 30 so as to be rotatable relative to the first balance shaft 30.
And an outer peripheral portion 31b provided integrally rotatably on the outer periphery of the inner peripheral portion 31a and having teeth 31c formed on the outer periphery thereof. The teeth 31c of the outer peripheral portion 31b
Are meshed with teeth formed on the outer periphery of the crank gear 21 (see FIG. 1). In this embodiment, the tooth width of the teeth 31c in the outer peripheral portion 31b and the crank gear 2
The tooth width of one tooth is set to be equal, and the tooth width of the counter gear 32 and the second driven gear 41 meshed with the gear 32 are also set to be equal.

As shown in FIG. 4, the outer periphery of the first balance shaft 30 is provided on the side of the counter gear 32 facing the first driven gear 31. A surrounding annular recess 51 is provided. On the inner bottom surface 51a of the concave portion 51, a plurality of locking projections 52 having a substantially rectangular cross section projecting toward the first driven gear 31 at equal angular intervals around the axis of the first balance shaft 30. (In this example, four as shown in FIG. 4). Further, a pair of locking holes 53 are formed on the inner bottom surface 51 a of the concave portion 51 at positions sandwiching the locking convex portion 52.

A stopper rubber 54 having a substantially trapezoidal cross section, which is locked by a locking projection 52 and a locking hole 53, is provided in the recess 51 at equal angular intervals around the axis of the first balance shaft 30. (In this example, four in this example) as well.

The stopper rubber 54 has a locking recess 54 c engaged with the locking projection 52 and a locking piece 54 d engaged with the locking hole 53. The engagement of the locking projections 52 with the locking recesses 54c and the locking pieces 54d with the locking holes 53 restrict the circumferential movement of the stopper rubber 54 in the recesses 51. I have. Further, even when the rotational force input from the crankshaft 20 to the balancer device becomes the largest,
The spring constant is set so as not to cause excessive deformation causing damage.

On the other hand, the inner peripheral portion 31a of the first driven gear 31
, A plurality of (four in this example) projecting toward the counter gear 32 is provided on a side surface facing the counter gear 32.
Are provided. The protruding portions 55 are provided at equal angular intervals around the axis of the first balance shaft 30 so as to be located at a predetermined angle from each of both opposing ends of the adjacent stopper rubber 54. Have been. Therefore, the first driven gear 31 and the counter gear 32 are configured to be relatively rotatable in a rotation phase range in which each of the protrusions 55 abuts on the end of the adjacent stopper rubber 54.

According to such a structure, when the rotational force transmitted from the crankshaft 20 sharply increases, for example, at the time of engine acceleration, the first driven gear 31 moves beyond the rotational phase range and the counter In the case of relative rotation with respect to the gear 32, the convex portion 55 comes into contact with the end of the stopper rubber 54, and the stopper rubber 54 elastically deforms in its circumferential direction. Thus, the rotational force of the first driven gear 31 is transmitted to the counter gear 32 while the relative rotation between the first driven gear 31 and the counter gear 32 is restricted.

On the other hand, as shown in FIG. 3, in the inner peripheral portion 31a of the first driven gear 31, the axial center of the first balance shaft 30 is provided on the side opposite to the side facing the counter gear 32. Centering on the first balance shaft 30
A concave portion 56 having an inner diameter larger than the outer diameter of is formed. Therefore, when the first driven gear 31 is engaged with the first balance shaft 30, an annular space is formed between the outer peripheral surface of the first balance shaft 30 and the inner peripheral surface of the concave portion 56. Will be done.

In this annular space, as shown in FIG.
Friction damper 57 for suppressing the relative rotation between the balance shaft 30 and the first driven gear 31 by frictional force
Is provided. The friction damper 57 is formed of an elastic material such as a rubber material, for example, in a shape along the inner wall of the annular space, specifically, in a U-shaped cross section. The friction damper 57 includes a fixing portion 57 a in which a core material made of a metal material is embedded and which is fixed to the inner wall surface of the concave portion 56, and a sliding member that slides on the outer peripheral surface of the first balance shaft 30. And a contact portion 57b. In the annular space, a coil spring 58, which is also annularly formed, is provided so as to sandwich the sliding contact portion 57 b between the coil spring 58 and the first balance shaft 30.

In the damper structure of this embodiment, when the engine rotation speed is low, the sliding contact portion 57 b is pressed against the outer peripheral surface of the first balance shaft 30 by the tightening force of the coil spring 58. Therefore, when the first driven gear 31 and the first balance shaft 30 relatively rotate, a relatively large frictional force is generated between the sliding contact portion 57b and the outer peripheral surface of the first balance shaft 30. .

On the other hand, as the engine speed increases, the centrifugal force acting on the coil spring 58 increases. Due to this centrifugal force, the tightening force of the coil spring 58 on the sliding contact portion 57b decreases, and as a result, the frictional force by the friction damper 57 decreases.

That is, according to the damper structure of the present embodiment, the first balance shaft 30 and the first driven gear 3
The frictional force for suppressing the relative rotation with respect to 1 acts as a smaller force as the engine rotation speed increases.

The coil spring 58 is formed in an annular shape, and is slidably contacted with the first balance shaft 30.
7b, the frictional force of the friction damper 57 reduces the friction force of the first balance shaft 30.
Act as substantially equal forces over the entire circumference in the circumferential direction.

Further, since the coil spring 58 can be easily deformed, it can be easily mounted. As described above, according to the present embodiment,
The following effects can be obtained.

(1) The coil spring 58 is formed in an annular shape, and the coil spring 58 is in sliding contact with the first balance shaft 30.
7b so as to be sandwiched. This allows
Due to the centrifugal force acting on the coil spring 58, the frictional force that suppresses the relative rotation between the first balance shaft 30 and the first driven gear 31 acts as a smaller force as the engine rotation speed increases. . Therefore, it is possible to suppress unnecessary wear of the friction damper 57 when the engine rotation speed is high, and to attenuate the vibration at the gear meshing portion.

(2) Since the coil spring 58 is formed in an annular shape, the frictional force of the friction damper 57 acts as a substantially equal force over the entire circumference of the first balance shaft in the circumferential direction. For this reason, uneven wear of the friction damper 57 is suppressed.

(3) Since the coil spring 58 can be easily deformed, it can be easily mounted. The above embodiment may be modified and implemented as follows.

In the above embodiment, the coil spring 58 is provided, but an elastic rubber formed in an annular shape may be provided instead. In the above embodiment, the coil spring 58 is provided so as to sandwich the sliding contact portion 57b of the friction damper 57 between the coil spring 58 and the first balance shaft 30. 6 is an enlarged sectional view corresponding to FIG. 3 and FIG. 7 is a sectional view corresponding to FIG.
A weight 63 may be provided on the back surface of the sliding contact portion 62b on the sliding contact surface with the first balance shaft 30. Even with such a damper mechanism 60, the frictional force that suppresses the relative rotation between the first balance shaft 30 and the first driven gear 31 is set to increase as the engine rotation speed decreases, and the engine rotation speed increases. Unnecessary wear of the friction damper 62 at the time can be suppressed, and the vibration at the gear meshing portion can be attenuated. Incidentally, in this damper mechanism 60, the friction damper 62
Is that the sliding contact portion 62b is the first balance shaft 3
0 is slidably provided on the outer peripheral surface while tightening the outer peripheral surface. In the sliding contact portion 62b, a plurality of (in this example, eight as shown in FIG. 7) weights 63 are provided on the back surface of the sliding contact surface with the first balance shaft 30. 30 are provided at equal angles about the axis. When the engine rotation speed is low, the first balance shaft 30 and the first driven gear 31
When the first and second shafts relatively rotate, the sliding contact portion 62b and the first balance shaft 30 slide, so that the friction damper 62 generates a relatively large frictional force. On the other hand, when the engine rotation speed increases, the centrifugal force acting on the weight 63 increases. Since the weight 63 is provided in the sliding contact portion 62b, the centrifugal force opposes the tightening force of the sliding contact portion 62b to the first balance shaft 30, and causes the sliding contact portion 62b to rotate the shaft 30. It acts in the direction of separating from the camera. Thereby, the first balance shaft 3
0, the tightening force of the sliding contact portion 62b with respect to
The frictional force of the friction damper 82 is reduced.

Also, instead of the above-mentioned weight 63, as shown in FIG. 8 as a cross-sectional structure of the damper mechanism 70, a mass 73 corresponding to the weight is integrally formed on the friction damper 72. You may make it.

(Second Embodiment) Hereinafter, a second embodiment in which the damper structure according to the present invention is applied to a balancer device for an internal combustion engine will be described.
The embodiment will be described with reference to FIG.

Here, the friction damper and its peripheral structure are different between the damper structure of the present embodiment and the damper structure of the above-described first embodiment. Further, a friction force control device for variably controlling the friction force of the friction damper by hydraulic pressure is newly provided. Hereinafter, the damper structure according to the present embodiment will be described focusing on these differences.

FIG. 9 shows a sectional structure of a damper mechanism 80 according to the present embodiment as a diagram corresponding to FIG. Note that, in FIG. 9, the same components as those illustrated in FIG. 3 are denoted by the same reference numerals, and redundant description thereof will be omitted.

First, the friction damper of this embodiment and its peripheral structure will be described. FIG. 9
As shown in FIG. 5, a pair of annular friction dampers 82 and 83 are provided in an annular space formed between the outer peripheral surface of the first balance shaft 30 and the inner peripheral surface of the concave portion 81.
Are the first driven gear 31 and the first balance shaft 30
Are provided as friction members for suppressing the relative rotation with respect to the frictional force. These friction dampers 8
Reference numerals 2 and 83 denote fixing portions 82a and 83a made of a metal material and fixed to the inner wall surface of the concave portion 81, and a sliding contact portion made of an elastic material such as a rubber material and slidingly contacting the outer peripheral surface of the first balance shaft 30. 82b and 83b.

In the damper structure of the present embodiment, basically, when the first driven gear 31 rotates relative to the counter gear 32, in other words, the first driven gear 31 At the time of relative rotation with respect to the balance shaft 30, a frictional force is generated between the sliding portions 82b and 83b and the outer peripheral surface of the first balance shaft 30, and the frictional force is generated by the relative rotation. It acts as a force for suppressing

Next, the details of a frictional force control device that variably controls the frictional force according to the engine speed will be described.
Outer peripheral surface of the first balance shaft 30, the concave portion 8
A hydraulic chamber 84 is formed as a space defined by the inner wall surface 1 and the friction dampers 82 and 83. Further, the damper structure of the present embodiment includes an oil tank 90 and an oil pump 91 for pumping lubricating oil in the tank 90 to each sliding portion of the internal combustion engine. The oil pump 9 is provided inside the bearing 92 in the internal combustion engine.
Oil passage 9 filled with lubricating oil discharged from 1
3 are formed. The first balance shaft 30
Is formed with an oil passage 94 which communicates the oil passage 93 with the hydraulic chamber 84. The lubricating oil discharged from the oil pump 91 is supplied into the hydraulic chamber 84 via the oil passages 93 and 94.

With such a structure, when the pressure of the lubricating oil in the hydraulic chamber 84 increases, the friction damper 8
The pressure for pressing the inner surfaces of the sliding portions 82b, 83b of the friction dampers 82, 83 increases, and as a result, these friction dampers 82, 8
3 is increased in the direction toward the first balance shaft 30 side. At this time, the friction dampers 82, 8
3 increases the frictional force.

On the contrary, when the pressure of the lubricating oil in the hydraulic chamber 84 is low, the two friction dampers 82, 8
3 is reduced in the direction toward the first balance shaft 30 side. Thereby, the friction dampers 82,
83 reduces the frictional force.

On the other hand, in this frictional force control device, a hydraulic control valve 95 for adjusting the hydraulic pressure applied to the hydraulic chamber 84 is provided between the oil pump 91 and the oil passage 93. Further, this device includes a rotation speed sensor 96 that outputs a signal corresponding to the engine rotation speed, and an electronic control device 97 that includes, for example, a microcomputer. The electronic control unit 97 takes in the detection signal of the rotation speed sensor 96, calculates the engine rotation speed based on the detection signal, and controls the driving of the hydraulic control valve 95 based on the calculation result.

The hydraulic control valve 95 is controlled by the electronic control unit 97 so that the hydraulic pressure applied to the hydraulic chamber 84 increases as the engine rotational speed decreases, and the engine rotational speed exceeds a predetermined rotational speed (for example, , 2000 revolutions / minute or more), the driving of the friction dampers 82, 83 is controlled so that the frictional force becomes almost “0”.

This is because the lower the engine speed, the greater the fluctuation of the torque transmitted from the crankshaft 20 to the first balance shaft 30. On the other hand, if the engine speed becomes higher than a predetermined speed, the first This is because the fluctuation of the rotational force does not become so large that the vibration between the teeth 31c of the driven gear 31 and the teeth of the crank gear becomes a problem.

That is, in the damper structure of the present embodiment, the first balance shaft 30 and the first driven gear 31
The frictional force that suppresses the relative rotation with the rotator acts as a larger force as the engine rotation speed decreases. On the other hand, when the engine rotation speed becomes equal to or higher than the predetermined speed, such frictional force does not act much. Therefore, it is possible to suppress unnecessary wear of the friction dampers 82 and 83 when the engine rotation speed is high, and to attenuate the vibration at the gear meshing portion.

The friction dampers 82 and 83 are formed in an annular shape, respectively, so that the friction dampers 8
2 and 83, the friction force of the first balance shaft 3
0 acts as a substantially equal force over the entire circumference in the circumferential direction.

As described above, according to the present embodiment, the following effects can be obtained. (1) The frictional force by the friction dampers 82 and 83 is variably controlled according to the engine speed. Therefore, it is possible to suppress unnecessary wear of the friction dampers 82 and 83 when the engine rotation speed is high, and to attenuate the vibration at the gear meshing portion. In addition, the frictional force can be adjusted to an optimal force in suppressing the relative rotation between the first driven gear 31 and the first balance shaft 30 according to the engine speed. Become.

(2) Since the friction dampers 82 and 83 are formed in an annular shape, the frictional force of the friction dampers 82 and 83 is reduced by the first balance shaft 3.
0 acts as a substantially equal force over the entire circumference in the circumferential direction. Therefore, the friction dampers 82, 83
Uneven wear can be suppressed.

(3) The outer peripheral surface of the first balance shaft 30, the inner wall surface of the concave portion 81, and both friction dampers 8
The hydraulic chamber 84 is formed by the sections 2 and 83, and the hydraulic pressure applied to the hydraulic chamber 84 is adjusted. Therefore, the friction damper 8 constituting one wall of the hydraulic chamber 84
It is possible to adjust the force for pressing the inner surfaces of the two and 83. Thereby, the frictional force by the friction dampers 82 and 83 can be adjusted.

The above embodiment may be modified and implemented as follows. In the above embodiment, the pressure of the lubricating oil applied to the hydraulic chamber 84 is adjusted through the drive control of the hydraulic control valve 95, but is not limited to this. This hydraulic control valve 95
Instead, a flow control valve is provided and the applied oil pressure is adjusted through the drive control thereof. Alternatively, instead of lubricating oil, a fluid such as air is supplied to the hydraulic chamber 84 and the supply pressure is adjusted. You may. The point is that the configuration may be appropriately changed as long as the fluid can be supplied to the compartment having at least one wall of the friction damper as one wall and the applied pressure can be variably controlled.

In the above-described embodiment, the hydraulic pressure applied to the hydraulic chamber 84 is variably controlled based on the engine speed.
You may make it variably set.

(Third Embodiment) Hereinafter, a third embodiment in which the damper structure according to the present invention is applied to a balancer device for an internal combustion engine will be described.
The embodiment will be described with reference to FIG.

Here, the structure of the friction damper, its peripheral structure, and the frictional force control device are different between the damper structure of the present embodiment and the above-described damper structure of the second embodiment. Hereinafter, the damper structure according to the present embodiment will be described focusing on these differences.

FIG. 10 shows a sectional structure of the damper mechanism 100 according to the present embodiment as a view corresponding to FIG. In FIG. 10, the same components as those illustrated in FIG. 9 are denoted by the same reference numerals.

First, the friction damper of the present embodiment and its peripheral structure will be described. FIG. 1
As shown in FIG. 0, an annular friction damper 102 is provided in an annular space formed between the outer peripheral surface of the first balance shaft 30 and the inner peripheral surface of the recess 101. The friction damper 102 is made of a metal material and fixed to the outer peripheral surface of the first balance shaft 30 and a side surface of the first driven gear 31 made of an elastic material such as a rubber material (FIG. 10). (The right side in FIG. 2). In addition, this friction damper 102
Due to the elastic force of the sliding contact portion 102b, the sliding contact portion 1
02b is arranged so as to be pressed against the side surface of the first driven gear 31.

In the damper structure of the present embodiment, basically, the first driven gear 31 and the first balance shaft 30
Is relatively rotated, a frictional force is generated between the sliding contact portion 102b and the side surface of the first driven gear 31, and the relative rotation is suppressed by the frictional force. I have.

Next, the frictional force control device according to the present embodiment will be described. In the friction damper 102, the back surface (the right side surface in FIG. 10) of the sliding contact surface with the first driven gear 31 is made of a magnetic material (for example, iron) which is formed in a ring shape and which is magnetized in a magnetic field. A driving unit 103 is provided.

Further, on the side (right side in FIG. 10) of the driving section 103, an electromagnetic coil 104 also formed in a ring shape is disposed so as to face the driving section 103 formed in a ring shape. The electromagnetic coil 104 is provided to be accommodated in a bracket 105 fixed to the internal combustion engine.

When current does not flow through the electromagnetic coil 104, the sliding contact portion 102b is pressed against the side surface of the first driven gear 31 by its own elastic force. At this time,
The friction damper 102 generates a relatively large friction force.

On the other hand, when a current flows through the electromagnetic coil 104, a magnetic flux is generated and the magnetic flux is generated by the driving unit 1.
The drive unit 103 is attracted in the direction of the electromagnetic coil 104 by the magnetic attraction generated by the magnetic flux. Since the driving section 103 is provided on the sliding contact section 102b, the magnetic attraction force is reduced by the driving section 10b.
3 acts in a direction to separate the sliding contact portion 102b from the first driven gear 31 against the elastic force of the first driven gear 31. As a result, the force for pressing the sliding contact portion 102b against the first driven gear 31 decreases, and as a result, the frictional force by the friction damper 102 decreases.

In the damper structure of this embodiment, the electronic control unit 97 controls the manner in which the electromagnetic coil 104 is energized. In this control, the frictional force generated by the friction damper 102 is set so as to increase the current amount as the engine rotation speed increases, and to increase the frictional force by the friction damper 102 when the engine rotation speed exceeds a predetermined rotation speed (for example, 2000 rotations / minute or more). The current supply mode is adjusted so as to be "0".

Thus, the frictional force that suppresses the relative rotation between the first driven gear 31 and the first balance shaft 30 acts as a larger force as the engine rotation speed is lower. On the other hand, when the engine rotation speed becomes equal to or higher than the predetermined speed, such frictional force does not act much. For this reason,
Friction damper 8 when engine speed is high
Unnecessary wear of the gears 2 and 83 can be suppressed, and the vibration at the gear meshing portion can be attenuated.

As described above, according to the present embodiment, the following effects can be obtained. (1) The frictional force of the friction damper 102 is variably controlled according to the engine speed. For this reason, when the engine speed is high, the friction damper 10
2, while suppressing unnecessary wear, vibrations at the gear meshing portion can be attenuated. In addition, the frictional force is applied to the first driven gear 31 according to the engine speed.
In order to suppress the relative rotation of the first balance shaft 30 and the first balance shaft 30, the force can be adjusted to an optimum force.

(2) Since the friction damper 102 is formed in an annular shape, the frictional force of the friction damper 102 acts as a substantially equal force over the entire circumference of the first balance shaft 30 in the circumferential direction. Therefore, uneven wear of the friction damper 102 can be suppressed.

(3) In the sliding contact portion 102b of the friction damper 102, a driving portion 103 made of a magnetic material is provided on the back surface of the sliding contact surface with the first driven gear 31, and
Electromagnetic coil 10 for applying magnetic attraction to drive unit 103
4 is provided, and the current applied to the electromagnetic coil 104 is adjusted according to the engine speed. This allows
Through the adjustment of the applied current, it is possible to adjust the electromagnetic attraction force acting in a direction to separate the driving unit 103 and, consequently, the sliding contact unit 102b from the first driven gear 31. For this reason, the frictional force by the friction damper 72 can be adjusted.

The above embodiment may be modified and implemented as follows. In the above embodiment, the sliding contact portion 102b of the friction damper 102 is formed of an elastic material,
Although the drive section 103 made of a magnetic material is provided in 2b, the sliding contact section may be made of a material that is a magnetic material and an elastic material, such as a magnetic rubber. According to such a configuration, the drive unit can be omitted.

In the above embodiment, the driving section 103 is made of a magnetic material that takes on magnetism in a magnetic field. However, the driving section 103 may be made of a permanent magnet. According to such a configuration, the degree of freedom for various settings of the frictional force control device, such as the shape of the drive unit and the electromagnetic coil, can be increased.

In addition, the electromagnetic coil may be disposed so as to surround the outer periphery of the driving unit. According to such a configuration, by adjusting the applied magnetic field of the magnetic field generated by the electromagnetic coil and variably controlling the applied current, the magnetic force applied to the drive unit by the magnetic field can be changed. This makes it possible to adjust the force that attracts the drive unit in the direction that separates the drive unit from the first driven gear 31.

In the above-described embodiment, the magnetic attraction force applied to the drive unit 103 is variably controlled based on the engine speed. However, the magnetic attraction force may be varied in consideration of any engine operating conditions. You may make it set.

(Fourth Embodiment) Hereinafter, a fourth embodiment in which the damper structure according to the present invention is applied to a balancer device for an internal combustion engine will be described.
The embodiment will be described with reference to FIGS. 11 and 12. FIG.

Here, only the structure of the damper mechanism is different between the damper structure of the present embodiment and the above-described damper structure of the first embodiment. Hereinafter, the damper structure according to the present embodiment will be described focusing on this difference.

FIG. 11 and FIG. 12 are views showing the cross-sectional structure of the damper mechanism 110 according to the present embodiment.
FIG. 11 shows a sectional structure taken along line 11-11 of FIG. 12 as a view corresponding to FIG. 3, and FIG.
A cross-sectional structure along the line 2-12 is shown as a diagram corresponding to FIG. Also, in FIGS. 11 and 12, FIG.
The same components as those illustrated in FIG. 4 are denoted by the same reference numerals.

As shown in FIGS. 11 and 12, the first
A guide groove 111 extending in the radial direction of the first balance shaft 30 is formed on a side surface of the driven gear 31 facing the counter gear 32. Further, on this side surface, an outer wall 112 is formed so as to protrude outward from the guide groove 111. In the guide groove 111, a column 113 extending in the direction of the counter gear 32 is provided while allowing the first balance shaft 30 to move in the radial direction. The column 113 is provided with a damper 114 formed of an elastic material such as a rubber material into an arc-shaped cross section.

Between the support 113 and the outer wall 112,
A coil spring 115 is provided so as to urge the column 113 in the axial direction of the first balance shaft, in other words, to press the damper 114 against the outer peripheral surface of the first balance shaft 30. . The guide groove 111, the outer wall 112, the support 113, the damper 114, and the coil spring 115 are provided at equal angles around the axis of the first balance shaft 30 (in this example, as shown in FIG. 12). 4) are provided.

In such a damper mechanism 110, basically, the first driven gear 31 and the first balance shaft 30
Is relatively rotated, a frictional force is generated between the damper 114 and the outer peripheral surface of the balance shaft 30, and the frictional force suppresses the relative rotation.

The side face of the counter gear 32 facing the first driven gear 31 has a plurality (4 in this example).
) Are formed to protrude. Note that the convex portions 116 are spaced at equal angular intervals around the axis of the first balance shaft 30 so as to be located at a predetermined angle from each of both opposing ends of the adjacent dampers 114. Is provided. Therefore, each convex portion 11
The first driven gear 31 and the counter gear 32 are configured to be able to rotate relative to each other in a rotation phase range in which 6 contacts the end of the adjacent damper 114.

The operation of the damper mechanism 110 will be described below. According to the damper mechanism 110, when the rotational force transmitted from the crankshaft 20 rapidly increases, for example, during engine acceleration, the first driven gear 3
When 1 rotates relative to the counter gear 32 beyond the above rotation phase range, the convex portion 116 comes into contact with the end of the damper 114, and the damper 114 elastically deforms in its circumferential direction. Thus, the rotational force of the first driven gear 31 is transmitted to the counter gear 32 while the relative rotation between the first driven gear 31 and the counter gear 32 is restricted.

In the damper mechanism 110, when the engine speed is low, the first driven gear 31
When rotating relative to the balance shaft 30 of
The damper 114 is pressed against the outer peripheral surface of the first balance shaft 30 by the urging force of the coil spring 115. Therefore, a relatively large frictional force is generated between the damper 114 and the outer peripheral surface of the first balance shaft 30.

On the other hand, as the engine speed increases, the centrifugal force acting on the damper 114 increases. Since this centrifugal force acts to oppose the urging force of the coil spring 115, the force of the coil spring 115 urging the damper 114 in the direction of the first balance shaft 30 is reduced. As a result,
The frictional force generated by the damper 114 is reduced.

That is, according to the damper structure of the present embodiment, the first driven gear 31 and the first balance shaft 3
The frictional force for suppressing the relative rotation with zero is set to be larger as the engine rotation speed is lower. Accordingly, it is possible to suppress unnecessary wear of the damper 114 when the engine rotation speed is high, and to attenuate the vibration at the gear meshing portion.

The above embodiments may be modified and implemented as follows. In the above embodiments, the first balance shaft 30
The present invention is applied to a friction damper or a damper structure that suppresses the relative rotation between the first driven gear 31 and the frictional force of the damper. However, the present invention is not limited to the frictional force, and the relative rotation is suppressed. The present invention can be similarly applied to a damper structure using a means for generating a damping force.

In each of the above embodiments, the damper structure according to the present invention is applied to the balancer device of the internal combustion engine. However, the present invention is not limited to the balancer device, but may be applied to other power transmission systems of the internal combustion engine. You may. Further, the damper structure according to the present invention may be applied to a power transmission system mounted on a device other than the internal combustion engine.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a first embodiment in which a damper structure according to the present invention is applied to a balancer device of an internal combustion engine.

FIG. 2 is a schematic diagram schematically showing the meshing state of each gear of the embodiment.

FIG. 3 is a sectional view showing a sectional structure of the damper mechanism of the embodiment.

FIG. 4 is a sectional view showing a sectional structure along line 4-4 in FIG. 3;

FIG. 5 is a sectional view showing a sectional structure along line 5-5 in FIG. 3;

FIG. 6 is a cross-sectional view showing a cross-sectional structure of a damper mechanism according to another embodiment of the damper structure according to the present invention.

FIG. 7 is a sectional view showing a sectional structure along line 7-7 in FIG. 6;

FIG. 8 is a sectional view showing a sectional structure of a damper mechanism according to another embodiment of the damper structure according to the present invention.

FIG. 9 is a sectional view showing a sectional structure of a damper mechanism of a second embodiment of the damper structure according to the present invention.

FIG. 10 is a sectional view showing a sectional structure of a damper mechanism of a third embodiment of the damper structure according to the present invention.

FIG. 11 is a sectional view showing a sectional structure of a damper mechanism of a fourth embodiment of the damper structure according to the present invention.

FIG. 12 is a sectional view showing a sectional structure taken along line 12-12 in FIG. 11;

FIG. 13 is a cross-sectional view showing a cross-sectional structure of a damper mechanism of a conventional damper structure.

FIG. 14 is a cross-sectional view showing a cross-sectional structure of a damper mechanism of a conventional damper structure.

[Explanation of symbols]

20 ... crankshaft, 21 ... crank gear, 30 ...
1st balance shaft, 30a ... shaft support part, 31 ... 1st driven gear, 31a ... inner peripheral part, 31b ... outer peripheral part, 31
c: teeth, 32: counter gear, 32a: concave portion, 33: unbalanced weight, 35: thrust bearing, 35a: concave portion, 40: second balance shaft, 40a: shaft support portion, 41: second driven gear, 41a: recess, 43: unbalanced weight, 45: thrust bearing, 45a: recess, 50, 70, 80, 90, 100: damper mechanism, 5
DESCRIPTION OF SYMBOLS 1 ... concave part, 51a ... inner bottom part, 52 ... locking convex part, 53 ... locking hole, 54 ... stopper rubber, 54c ... locking concave part, 54d
... locking pieces, 55 ... convex parts, 56, 81, 101 ... concave parts, 5
7, 62, 72, 82, 83, 102 ... friction dampers, 57a, 62a, 72a, 82a, 83a, 10
2a: fixing portion, 57b, 62b, 72b, 82b, 83
b, 102b: sliding contact portion, 58: coil spring, 73: mass portion, 84: hydraulic chamber, 90: oil tank, 91: oil pump, 92: bearing portion, 93, 94: oil passage, 95
... Hydraulic control valve, 96 ... Rotation speed sensor, 97 ... Electronic control device, 103 ... Drive unit, 104 ... Electromagnetic coil, 105 ...
Bracket, 111: guide groove, 112: outer wall, 113
... Support, 114 ... damper, 115 ... coil spring, 116
... projections.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koichi Shimizu 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Satoshi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Hiroshi Kosuge 1-term Toyota-cho, Toyota-shi, Aichi F-term in Toyota Motor Corporation (reference) 3J030 AA06 AA07 AA14 BB02

Claims (10)

[Claims] A first gear connected to a first rotating shaft;
A power transmission system including a second gear provided on the second rotation shaft while being meshed with the first gear and being allowed to rotate relative to the second rotation shaft; A power transmission system in which a friction member is provided between the second rotation shaft and the second gear as a damper member for suppressing the relative rotation between the second rotation shaft and the second gear by a frictional force. In the above damper structure, the friction member is provided over the entire circumference in the circumferential direction between the second rotation shaft and the second gear, and a friction force variable member that varies a friction force by the friction member is provided. A damper structure for a power transmission system, wherein the damper structure is provided around the entire circumference of the friction member. 2. A damper structure for a power transmission system according to claim 1, wherein said frictional force variable member is a coil spring provided so as to sandwich said frictional member between said frictional member and said second rotating shaft. 3. A first gear connected to a first rotating shaft,
A power transmission system including a second gear provided on the second rotation shaft while being meshed with the first gear and being allowed to rotate relative to the second rotation shaft; A power transmission system in which a friction member is provided between the second rotation shaft and the second gear as a damper member for suppressing relative rotation between the second rotation shaft and the second gear by a frictional force. The damper structure for a power transmission system, further comprising: a frictional force control unit that variably controls a frictional force by the friction member. 4. The friction member is made of an elastic material having at least one wall thereof as one wall of a hydraulic chamber, and the friction force control means variably controls a hydraulic pressure applied to the hydraulic chamber. 2. The damper structure of the power transmission system according to item 1. 5. The friction member has a magnetic member on the back surface of the sliding surface, and the friction force control means has an electromagnet and variably controls an electromagnetic force applied to the magnetic member. 4. The damper structure of the power transmission system according to 3. 6. A first gear connected to a first rotating shaft,
A power transmission system including a second gear provided on the second rotation shaft while being meshed with the first gear and being allowed to rotate relative to the second rotation shaft; Power transmission in which damping force generating means for generating damping force for suppressing relative rotation between the second rotating shaft and the second gear is provided between the second rotating shaft and the second gear. In the system damper structure, the damping force generating means is provided over the entire circumference in the circumferential direction between the second rotation shaft and the second gear, and the damping force generated by the damping force generating means is variable. A damper structure for a power transmission system, characterized in that the damping force variable means is provided around the entire circumference of the damping force generating means. 7. A damper for a power transmission system according to claim 6, wherein said damping force variable means is a coil spring provided so as to sandwich said damping force generating means between said second rotating shaft and said second rotating shaft. Construction. 8. A first gear connected to a first rotating shaft,
A power transmission system including a second gear provided on the second rotation shaft while being meshed with the first gear and being allowed to rotate relative to the second rotation shaft; Power transmission in which damping force generating means for generating a damping force for suppressing relative rotation between the second rotating shaft and the second gear is provided between the second rotating shaft and the second gear. A damper structure for a power transmission system, comprising: damping force control means for variably controlling damping force by the damping force generation means. 9. The damping force generating means comprises an elastic member having at least one wall thereof as one wall of a hydraulic chamber, and the damping force control means variably controls a hydraulic pressure applied to the hydraulic chamber. Item 10. A power transmission system damper structure according to Item 8. 10. The damping force generating means includes a magnetic member,
9. The power transmission system damper structure according to claim 8, wherein said damping force control means has an electromagnet and variably controls an electromagnetic force applied to said magnetic member.