JPH09280317A - Flywheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flywheel in which a size in the axial direction is not increased but a high torque fluctuation absorbing city is attained. SOLUTION: The flywheel is provided with a driving side flywheel 1 rotatably arranged around its axis in a relative manner and a driven-side flywheel 2. The driving-side flywheel 1 is provided with some laminated leaf springs 14 resiliently deformed in the radial direction and the driven-side flywheel 2 is provided with a cam 18 having a cam surface 21 directed in the radial direction. These is provided a follower 23 which can be moved in the radial direction while it is being abutted against the cam surface 21 and the laminated leaf springs 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a flywheel for smoothing fluctuations in rotation of a vehicle engine, and more particularly to a flywheel having a damper that absorbs torque fluctuations.

[0002]

2. Description of the Related Art Generally, an engine for a vehicle is essentially inevitably subject to periodic torque fluctuations within one revolution of a crankshaft (drive shaft). It is installed. In order to further enhance the function of absorbing torque fluctuations in the clutch mechanism, the flywheel is divided into a drive-side flywheel and a driven-side flywheel, and a two-part split flywheel in which they are connected by a spring or a friction mechanism is known. Has been. An example of such a flywheel is described in Japanese Utility Model Publication No. 7-33000.

The flywheel described in the above publication will be described with reference to FIG. 6. This flywheel comprises a drive side flywheel 101 and a driven side flywheel 102 which are arranged so as to be relatively rotatable about a central axis A. It is divided into two parts. Drive side flywheel 101
Is an outer ring 103 having a ring gear meshed with a drive gear such as a starter, and an outer ring 103.
Drive plates 104, 105 provided on both sides of the
And an elastic member, for example, a coil spring 106, which is circumferentially arranged on the inner peripheral side of the outer ring 103, and an inner ring 107 fixed to the drive plate 104 with screws or the like. The inner ring 107 is connected to a drive shaft (not shown) of the engine, and the torque of the drive shaft causes the drive side flywheel 10 to rotate.
1, and the drive side flywheel 101 is rotated integrally.

On the other hand, the driven flywheel 102 is formed in a disk shape having substantially the same diameter as the driving flywheel 101, and a circular hole 108 is provided in the center thereof. An annular friction mechanism 109 is fixed to the circular hole 108 using a screw or the like, and a bearing 110 is arranged between the friction mechanism 109 and the inner ring 107. An auxiliary spring 111 is interposed between the friction mechanism 109 and the driven flywheel 102. Therefore, the torque of the drive side flywheel 101 is transmitted to the driven side flywheel 102 via the coil spring 106 and the friction mechanism 109. Driven flywheel 10
2 is connected to other clutch mechanism components and the like via a pin 111.

Although a detailed description of the friction mechanism 109 is omitted here, the friction mechanism 109 is the drive side flywheel 1.
01 and the driven-side flywheel 102 are composed of two friction plates inserted in a relative rotating portion and a cone spring that presses the friction plates in the axial direction, and temporarily slides only when the torque exceeds a certain value. It is like this. Therefore, for example, in a normal rotation range where the engine speed is equal to or higher than the idling state, the torque fluctuation is small, so that the friction mechanism 109 does not slip, and the elastic force (spring characteristic) between the coil spring 106 and the auxiliary spring 111.
As a result, the effect of absorbing the speed fluctuation is enhanced, the deflection of the auxiliary spring 111 becomes large with respect to the torque fluctuation in the low rotation state below the idling rotation, and the friction mechanism 109 slips, so that the fluctuation absorption of only the coil spring 106 is temporarily absorbed. As a characteristic, resonance between the drive side flywheel 101 and the driven side flywheel 102 is avoided.

FIG. 5 shows an example of the vibration characteristics of the flywheel, in which the horizontal axis represents the engine speed and the vertical axis represents the vibration amplitude ratio (output / input). Assuming that the engine speed by the starter is n1 and the engine speed during idling is n2, the conventional engine speed as shown in FIG.
The vibration characteristic of the split flywheel is in the state shown by the solid line B. Therefore, there is no problem because it is in the stable range in the use state, but since the resonance point exists between n1 and n2, the drive side flywheel 101 and the driven side flywheel 102 resonate when the engine is started by the starter. There is a possibility that the engine will stop, and improvement was desired.

[0007]

SUMMARY OF THE INVENTION To improve this,
The coil spring is made softer, that is, the elastic force is reduced to enhance the torque change absorbing ability, that is, the energy absorbing ability. As shown by the dotted line C in FIG. It is desirable to set a low speed. As is well known, the spring constant k of a coil spring is k = P / δ = d ⁴ G / 64nR
^{Since it} is determined by ³ , it is effective to increase the winding radius R if the material is constant. However, as can be easily understood from FIG. 6, since the coil spring is mounted in the circumferential direction with respect to the drive side flywheel 101, increasing the winding radius R increases the cross-sectional dimension of the coil spring. Therefore, there arises a problem that the axial thickness of the entire flywheel increases and the flywheel becomes large.

Further, in the conventional flywheel, a bearing 110 is required in order to make the relative rotation between the drive side flywheel 101 and the driven side flywheel 102 smooth, but this bearing 110 has a large mass in the driven side flywheel. Since it supports 102, there is no choice but to use a large outer diameter, which also causes a size increase, and there is a disadvantage that the cost becomes high.

The present invention has been made in view of the above circumstances, and a flywheel capable of improving the torque fluctuation absorbing ability by the drive side flywheel and the driven side flywheel without increasing the axial dimension. It is intended to be provided.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a drive side flywheel and a driven side flywheel which are arranged so as to be relatively rotatable about the same axis, and a drive side flywheel thereof. In a flywheel provided with an elastic member that is elastically deformed by relative rotation between the side flywheel and the driven side flywheel, the axis line is surrounded by either the drive side flywheel or the driven side flywheel. And a cam surface directed in the radial direction is provided, and the elastic member is arranged in a state of elastically deforming in the radial direction at a position facing the cam surface on the other side,
A follower pressed against the cam surface by the elastic member is provided, and the cam surface is formed in a shape that moves the follower to the elastic member side by relative rotation of the drive side flywheel and the driven side flywheel. It is characterized by being present.

Therefore, according to the present invention, the cam surface is formed in such a shape that the follower is moved in the direction in which the elastic member is elastically deformed by the relative rotation of the drive side flywheel and the driven side flywheel. , The elastic force of this elastic member acts as a resistance against the relative rotation between the drive side flywheel and the driven side flywheel,
Therefore, the torque input to the drive side flywheel is transmitted to the driven side flywheel via the cam surface, the follower and the elastic member.

When the torque input to the drive side flywheel fluctuates, a resistance force due to the inertial mass of the driven side flywheel acts to generate a load that deforms the elastic member. That is, the cam surface deforms the elastic member via the follower, and relative rotation between the drive side flywheel and the driven side flywheel occurs. As a result, the fluctuation of the input torque is absorbed by the deformation of the elastic member. As described above, in the flywheel of the present invention, since the driven side flywheel is supported by the cam surface, the follower, and the elastic member, the conventional bearing becomes unnecessary, and since the variable torque is absorbed by the elastic deformation in the radial direction, The amount of energy that can be absorbed can be increased without increasing the space in the axial direction.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the flywheel of the present invention will be described with reference to FIGS. The flywheel shown in these drawings has a so-called two-divided structure, and includes a drive-side flywheel 1 and a driven-side flywheel 2 which are arranged so as to be relatively rotatable about a single central axis E. The drive-side flywheel 1 includes an outer ring 3 having a ring gear meshed with a drive gear such as a starter, and drive plates 4 and 5 formed by pressing a metal plate.

The drive plate 4 is substantially orthogonal to the axis E, and is integrally formed on the entire circumference of the disk portion 7 and the disk portion 7 that is attached to the drive shaft (not shown) of the engine by the screw 6. And a flange portion 9 that is bent toward the driven flywheel 2 side and a flange 9 that is integrally bent from the end portion of the cylindrical portion 8 on the driven flywheel 2 side toward the outer peripheral side. I have it.

A plurality of holes 7A penetrating in the thickness direction are provided on the same circumference of the disk portion 7, and a driven fly is provided on the same circumference on the outer periphery of the plurality of holes 7A. A plurality of holding portions 10 are provided which are raised toward the wheel 2 side. In the embodiment of FIG. 1, the three holding portions 10 are
They are arranged at positions corresponding to 2 o'clock, 6 o'clock, and 10 o'clock on the dial of the watch at intervals of 20 degrees.
Is provided with a hole 11 penetrating in the radial direction.

The cylindrical portion 8 is fitted and fixed to the inner peripheral surface 3A of the outer ring 3, and the cylindrical portion 8 has a plurality of raised portions 1 bent inward toward the inside.
2 are provided. In the embodiment of FIG. 1, three ridges 1
0 at 120 degree intervals, 12 o'clock, 4 o'clock on the clock face,
They are arranged at the positions corresponding to 8 o'clock, respectively. That is, each of the holding portions 10 and each of the raised portions 12 is 6 in the circumferential direction.
They are arranged alternately at 0 degree intervals.

Further, the flange 9 is in contact with the end face of the outer ring 3 on the driven flywheel 2 side, and the outer diameter of the drive plate 4 and the outer diameter of the drive plate 5 are set to be substantially the same. The flange 9 of the drive plate 4 and the outer periphery of the drive plate 5 are joined and fixed, and a hole 13 is formed at the center of the drive plate 5 so as to penetrate therethrough.

Between the raised portions 12 between the drive plate 4 and the drive plate 5, three leaf springs 14 which are elastically deformed in the radial direction of the drive plate 4 are provided. Each leaf spring 14 is
It is configured by fixing a plurality of laminated plate-like bodies with bolts 15, and each leaf spring 14 is arranged outside each holding portion 10. For this reason, both ends of each leaf spring 14 in the longitudinal direction are brought into contact with the raised portions 12 to restrict movement in the circumferential direction, and movements in the axial direction are restricted by the drive plate 4 and the drive plate 5. Has been done.

On the other hand, a boss 16 centering on the central axis E is provided on the inner peripheral side of the driven flywheel 2, and a plurality of axially penetrating bosses 16 are provided on the same circumference. A shaft hole 17 is provided. The outer diameter of the boss 16 is set smaller than the inner diameter of the hole 13 of the drive plate 5, and the boss 16 is inserted into the hole 13.

Inside the holding portion 10 between the drive plate 4 and the drive plate 5, a substantially triangular cam 18 whose outer peripheral surface is a convex arc surface is arranged. The shaft hole 1 of the boss 16 is provided on the same circumference of the cam 18.
7, a plurality of shaft holes 19 are formed so as to penetrate, and the drive side flywheel 2 and the cam 18 are fixed by the rivets 20 inserted into the shaft holes 17 and the shaft holes 19.
The end of the rivet 20 on the drive plate 4 side is arranged in the hole 7A of the drive plate 4. Cam 1
Three arc-shaped cam surfaces 21 are formed on the outer periphery of the disk 8. The curvature of the cam surface 21 is set to be smaller than the circumscribing circle (not shown) of the apex of the cam 18 (large curvature radius). Further, a hole 22 penetrating in the axial direction is provided at the center of the cam 18. The head of the screw 6 is located in the hole 22.

Between the cam 18 and each leaf spring 14, three followers (contactors) 23 corresponding to each cam surface 21 are provided. Each follower 23 is formed in a pin shape, and is inserted into the hole 11 of each holding portion 10 and held so as to be movable in the radial direction of the drive plate 4. Both ends of each follower 23 are in contact with each leaf spring 14 and each cam surface 21.

In this way, the follower 23 and the cam 18 are brought into contact with each other, and the elastic force of each leaf spring 14 restricts the movement of the drive side flywheel 1 and the driven side flywheel 2 in the direction orthogonal to the axis E. Therefore, the bearing for positioning the drive side flywheel 1 and the driven side flywheel 2 in the direction orthogonal to the axis E is not used.

An elastic member 24 composed of, for example, a cone spring or a wave washer is arranged between the facing surfaces of the drive plate 5 and the cam 18, and the cam 18 is driven by the elastic force of the elastic member 24. Is urged toward the disk 7 side. An annular spacer 25 is provided between the cam 18 and the disc 7. In this way, the cam 18 is prevented from directly contacting the drive plates 4 and 5. Further, the relative movement of the drive side flywheel 1 and the driven side flywheel 2 in the axial direction is caused by the elastic member 24 and the spacer 25.
Regulated by

Next, the operation of the flywheel having the above structure will be described. First, when the torque output from the drive shaft of the engine is transmitted to the drive plate 4, the holding portion 1
The follower 23 inserted in the hole 11 of 0 rotates with the drive plate 4. On the other hand, the cam surface 21 against which the follower 23 is pressed has a shape in which the distance from the central axis E increases toward the end side thereof, and the follower 23 is overlapped in order to shift from the center portion of the cam surface 21. Since it is necessary to elastically deform the leaf spring 14, the leaf spring 14 and the driven flywheel 2 that fixes the leaf spring 14 in the circumferential direction are connected to the cam 18 via the follower 23 with a predetermined strength. Has been done. Therefore, when a torque is input to the drive-side flywheel 1, the torque according to the elastic force of the leaf spring 14 is transmitted to the driven-side flywheel 2 and the entire body rotates integrally. When the driven flywheel 2 is configured to press the clutch disc to engage the clutch (not shown), the transmission (not shown) is passed through the clutch disc. ) Is input torque.

When the torque input to the drive side flywheel 1 fluctuates while the torque is being transmitted as described above, the inertial mass of the driven side flywheel 2 and the members connected thereto is large. The inertial mass on the driven flywheel 2 side acts as a resistance force against a sudden increase in torque, causing the leaf springs 14 to bend and the flywheels 1 and 2 to rotate relative to each other. Further, when the input torque changes in the decreasing direction, the follower 23 tries to return to a stable state by the elastic force of the leaf spring 14, that is, in the central portion of the cam surface 21 where the leaf spring 14 is least deformed. The flywheels 1 and 2 are returned and relatively rotated in the opposite direction to the above case.

Explaining this in detail with reference to FIG. 3, when a constant torque is input to the drive side flywheel 1, the cam 18 integral with the drive side flywheel 1 has a follower 23 on its cam surface 21 and elasticity of the leaf spring 14. The drive-side flywheel 1 and the driven-side flywheel 2 are relatively rotated (relatively twisted) by moving them outward in the radial direction against the force. In this state, the input torque and the elastic force of the leaf spring 14 are balanced, and the follower 23, as shown in FIG. 3B, is different from the unloaded state shown in FIG. The cam surface 21 comes into contact with a position deviated from the center of the cam surface 21.

FIG. 4 shows the cam 1 when it is displaced from the unloaded state shown in FIG. 3A to the loaded state shown in FIG. 3B.
The positional relationship between 8 and the follower 23 is shown. In FIG. 4, the cam 18 and the follower 23 corresponding to the unloaded state are shown by solid lines, and the cam 18 and the follower 2 corresponding to the loaded state are shown.
3 and 3 are indicated by a chain line. That is, in the unloaded state, the cam 18 and the follower 23 are in contact with each other at a point A0, which is a predetermined linear distance from the center O of the cam 18, and in the loaded state, the cam 18 and the follower 23 are linear distance from the center O. Abut at point A1 which is longer than point A0.

The rotation angle of the cam 18 that causes the deviation δ in the radial direction between the point A0 and the point A1 is set to a large value by making the cam surface 21 a curved surface close to an arc centered on the center O. Therefore, the spring constant of the leaf spring 14 as seen from the displacement in the circumferential direction is a value obtained by doubling the actual spring constant by the ratio of the deviation δ and the arc length of each point A0, A1. That is, the large relative rotation between the drive-side flywheel 1 and the driven-side flywheel 2 causes the leaf spring 1 to overlap.
Since it is absorbed by a small elastic deformation of 4, the leaf spring 14 has a large amount of energy absorption and functions as a so-called soft elastic member.

Therefore, when the input torque fluctuates under the load condition shown in FIG. 3 (b), the leaf spring 14 further bends to absorb the energy in response to the increase in the torque, and the subsequent reduction in the torque occurs. The elastic return of the leaf spring 14 causes the follower 23 to move relative to the unloaded position. In this way, the leaf spring 14 which is an elastic member is elastically deformed to cause relative rotation between the drive-side flywheel 1 and the driven-side flywheel 2, so that the fluctuation of the torque input to the drive-side flywheel 1 is caused here. It is not absorbed and directly output to the driven flywheel 2. Since such a vibration is absorbed by the leaf spring having a substantially small spring constant by using the cam mechanism, the vibration does not resonate even at low frequency torque fluctuations at the time of engine start. Can be relaxed.

And in the above flywheel,
By changing the curvature and the shape of the cam surface 21 of the cam 18, the vibration damping characteristic can be arbitrarily adjusted. Since there is no particular factor that increases the plate width of the leaf spring 14, the length of the flywheel in the axial direction can be suppressed.

Further, in this embodiment, the cams 18 are supported and centered in the radial direction by the leaf springs 14 arranged at equal intervals or in point symmetry, so that the drive side flywheel 1 and the driven side flywheel 2 are connected. Since it is not necessary to dispose a bearing between them, the structure of the flywheel is simple and the assembly is easy, and at the same time, the manufacturing cost can be suppressed.

In this embodiment, the follower 23 and the leaf spring 14 are arranged on the outer peripheral side of the cam 18, but in the present invention, the cam is arranged on the outer peripheral side of the follower and the leaf spring. Even when (not shown) is adopted, the same effect as above can be obtained. It is also possible to adopt a configuration in which the cam is attached to the drive side flywheel while the laminated leaf spring is attached to the driven side flywheel. However, as in this embodiment, the laminated leaf spring 14 having a large mass is used. The one attached to the drive side flywheel 1
The increased inertial mass is advantageous for noise reduction and the like.

Further, since the stroke may be short as the elastic member in the present invention, a laminated leaf spring having a plurality of laminated sheets to enhance the energy storage capacity is suitable, but the invention is not limited to this, and a coil spring, a rubber or the like. , Any elastic member such as an air spring. Even a slightly stiff spring,
The excellent vibration damping function can be maintained by using the cam 18 and the follower 23 as shown in this embodiment.

Further, in this embodiment, the cam 18 is formed in a substantially triangular shape with the convex arc surface as the outer surface, and the three leaf springs 14 are arranged. However, the shape of the cam surface may be changed as required. Therefore, an appropriate shape can be adopted, and four or more leaf springs or elastic members corresponding thereto can be arranged.

[0035]

As described above, according to the present invention, when the drive-side flywheel and the driven-side flywheel rotate relative to each other due to the fluctuation of the input torque, the relative rotation is brought into contact with the cam surface and this. Since the follower that is present converts it into a radial displacement and the radial displacement of the elastic member absorbs the torque fluctuation, a large relative rotation can be converted into a small radial displacement, so that the substantial elasticity of the elastic member is reduced. The coefficient can be reduced to improve the energy absorption performance. Therefore, according to the flywheel of the present invention, it is possible to effectively absorb low-frequency torque fluctuations at the time of starting the reciprocating engine, and prevent resonance and deterioration of riding comfort due to the resonance, or engine start failure. . And features like this
Since the cam mechanism and the elastic member elastically deformed in the radial direction by the cam mechanism are used, the axial dimension of the flywheel as a whole can be shortened, and at the same time, the overall size and weight can be reduced.

Further, according to the present invention, since the driven flywheel is rotatably supported via the cam, follower and elastic member, it is not necessary to dispose a bearing between the two, resulting in a relatively expensive component. It is possible to abolish the bearing that has been used in the past and reduce the cost as well as the size and weight.

[Brief description of drawings]

FIG. 1 is a front sectional view of a two-part split flywheel showing an embodiment of the present invention.

FIG. 2 shows a flywheel of the present invention, which is II- of FIG.
It is sectional drawing in the II line.

3 (a) and 3 (b) are front sectional views showing a relative rotation operation between a drive side flywheel and a driven side flywheel in the flywheel of the present invention.

FIG. 4 is a conceptual diagram illustrating a positional relationship between a cam and a follower when the drive side flywheel and the driven side flywheel in the flywheel of the present invention rotate relative to each other.

FIG. 5 is a characteristic curve diagram showing a relationship between an engine speed and a vibration amplitude ratio of a flywheel.

FIG. 6 is a sectional view of a conventional split flywheel.

[Explanation of symbols]

 1 Drive side flywheel 2 Driven side flywheel 14 Laminated leaf spring (elastic member) 21 Cam surface 23 Follower

Claims (1)

[Claims] 1. A drive-side flywheel and a driven-side flywheel, which are arranged so as to be relatively rotatable about the same axis, and an elastic member which is elastically deformed by relative rotation of the drive-side flywheel and the driven-side flywheel. In a flywheel provided with, on either one of the drive-side flywheel or the driven-side flywheel, a cam surface that surrounds the axis and faces in a radial direction is provided, and the cam surface on the other side is provided. At a location facing each other, the elastic member is disposed in a state of being elastically deformed in the radial direction, and a follower pressed against the cam surface by the elastic member is provided, and the cam surface is the drive-side flywheel. A type in which the follower is moved to the elastic member side by relative rotation with the driven flywheel. Flywheel, characterized in that it is formed.