JP3518219B2 - Flywheel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flywheel, and more particularly to an improvement of a flywheel in which a ring gear having external teeth is integrally provided on an outer peripheral portion.

[0002]

2. Description of the Related Art Engines that operate by combustion of fuel are widely used in automobiles and the like. However, it is inevitable that such an engine causes periodic fluctuations in rotation (torque fluctuations) due to explosions. A flywheel is usually attached to a crankshaft or the like to suppress fluctuation. In addition to the engine, a flywheel is used for a rotating member that causes periodical rotation fluctuations in order to suppress the rotation fluctuations.

The above flywheel for a vehicle is usually provided with a ring gear with which a drive pinion of a starter for rotationally driving (cranking) a crankshaft for starting an engine is meshed. The pinion is linearly reciprocated in a direction parallel to the axis of the flywheel, and when the engine is started, it is moved to a meshing position where it meshes with the ring gear to drive the flywheel to rotate, while normally the meshing with the ring gear is released. Held in position. The above-mentioned ring gear is generally provided with a large number of teeth by cutting such as hobbing or pinion cutter, and then fixedly integrated with the flywheel by press fitting, shrink fitting, or the like. As described in Japanese Patent No. 282766, it is considered to provide a ring gear integrally with the flywheel by rolling.

[0004]

However, the above-described conventional flywheel ring gear is not necessarily satisfactory because it does not particularly mention the shape of its teeth. That is, the drive pinion is meshed with the ring gear in the direction parallel to the axis thereof,
If the drive pinion comes into contact with the end faces (front face) of the teeth of the ring gear at the time of rushing in, it will be meshed with the ring gear when the drive pinion subsequently rotates, which may cause abnormal noise or shorten the service life. I was afraid. In particular, when a ring gear is provided by rolling, spheroidal graphite cast iron or the like is preferably used, but since mechanical strength is lower than steel, cracks and the like are likely to occur due to impact.

On the other hand, it is conceivable to apply top chamfering (topping) to the teeth of the ring gear. However, if the top chamfering is increased, the deviation from the involute tooth profile will increase and the meshing ratio will decrease. The edge of the blade comes into contact with the shoulder, which causes fluctuation in rotation, which causes a different impact from that at the time of entry. This is the same not only when driven by the drive pinion but also when power is transmitted from the flywheel side to the drive pinion due to the explosion of the engine.

Further, when the ring gear is integrally formed on the flywheel by rolling, if a material having a sufficient strength is used as the ring gear, a large load will be applied during rolling and energy efficiency will be impaired. This included problems such as not being able to obtain the life of the rolling die sufficiently.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the shape of teeth of a ring gear integrally provided on a flywheel.

[0008]

In order to achieve such an object, a first aspect of the invention is that a ring gear having a substantially disk shape and having external teeth is integrally provided on an outer peripheral portion thereof. A flywheel in which a drive pinion is engaged in a direction substantially parallel to the axial center of the ring gear and is rotationally driven in a predetermined constant rotation direction, and is rotationally driven by the drive pinion among a pair of tooth surfaces of the ring gear. It is characterized in that the top chamfering amount of the first tooth surface to which the motion is transmitted at the time of movement is made larger than the top chamfering amount of the opposite second tooth surface.

A second invention is the first invention according to the first invention.
Among the tooth flanks, the amount of chamfering on the front side where the drive pinion projects in the tooth width direction is made larger than the amount of chamfering on the central portion in the tooth width direction.

According to a third aspect of the invention, a ring gear having a substantially disk shape and having external teeth is integrally provided on the outer peripheral portion, and the drive pinion is meshed with the ring gear in a direction substantially parallel to the axis. A flywheel that is rotationally driven in a predetermined constant rotational direction, and at least a first tooth surface of the pair of tooth surfaces of the ring gear to which motion is transmitted when rotationally driven by the drive pinion. The top chamfering is performed, and the top chamfering amount on the front side where the drive pinion projects in the tooth width direction is larger than the top chamfering amount of the central portion in the tooth width direction.

[0011]

According to a fourth aspect of the present invention, it has a substantially disc shape.
Ring gear with external teeth is integrated into the outer periphery by rolling process
On the ring gear that is approximately parallel to the axis.
The drive pinion is engaged from the direction and the predetermined one
A flywheel driven to rotate in a constant rotation direction,
(a) the teeth of the ring gear, the effective tooth width from the end portion of the front side coming enters said drive pinion in the tooth width direction to the middle portion is engaged with a driving pinion, with its effective face width portion, the rolling by the groove bottom shape during the forming teeth of rolling dies for performing granulation process is transferred to the tooth tip portion of the teeth of the ring gear, with one top chamfer is provided in the first to third aspects of the invention On the other hand, (b) the rolling process is performed so that the tip circle diameter of the surplus portion on the back surface side of the effective tooth width portion is smaller than the tip circle diameter of the effective tooth width portion.
Of the previous flywheel rough materials, the ring gear was rolled
The part to be worked and the part corresponding to the surplus part of at least one of the processed teeth of the rolling die are intended.
The size of the ring gear teeth corresponding to the tooth overhang direction has been reduced . (C) At the start of rolling, the rolling die
The processed tooth bites into the rolled portion in the effective tooth width portion.
Just insert the excess part as the rolling process progresses.
The entire tooth width direction bites into the rolled part.
The diameter of the tip circle of the ring gear after rolling is the surplus part.
It is characterized in that it becomes smaller in size , and in the surplus portion, a space for receiving the surplus thickness of the effective tooth width portion is formed between the rolled portion and the processed tooth.

[0013]

The flywheel according to the first aspect of the invention has the first feature that the movement is transmitted when the flywheel is rotationally driven by the drive pinion.
The relatively large top chamfer on the tooth surface reduces the impact when the drive pinion is engaged from the direction parallel to the shaft center, which may cause abnormal noise, damage the teeth, or shorten the service life due to fatigue. Suppressed. Since the top chamfering amount of the second tooth surface on the opposite side is smaller than the top chamfering amount of the first tooth surface, the meshing ratio increases accordingly, and power is transmitted from the flywheel side to the drive pinion due to, for example, an engine explosion. At the time of meshing rotation, fluctuations in rotation due to shoulder contact of edges such as tooth tips are suppressed, and impact during meshing rotation is reduced. That is, the top chamfering amount of the first tooth surface is set to the second
Since the amount of chamfering is larger than the top chamfer of the tooth surface, it is possible to mitigate the impact at the time of plunging the drive pinion while suppressing an increase in the impact during the meshing rotation of the drive pinion and the ring gear.

In the second aspect of the present invention, the front chamfering amount of the first tooth flank on the front side where the drive pinion projects in the tooth width direction is made larger than the top chamfering amount of the central portion in the tooth width direction. , The impact at the time of plunging can be alleviated while maintaining a large meshing ratio on the first tooth flank side, and compared with the case where the top chamfering amount on the first tooth flank side is increased for the entire tooth, from the drive pinion side Even during meshing rotation in which power is transmitted to the flywheel, rotation fluctuation due to shoulder contact of an edge such as a tooth tip is suppressed, and the impact during meshing rotation is reduced.

In the flywheel of the third aspect of the invention, at least the first tooth surface is chamfered at the top, and the front chamfering amount on the front side where the drive pinion projects in the tooth width direction is the central portion in the tooth width direction. Since it is made larger than the top chamfering amount of the tooth, the impact at the time of rush can be alleviated while maintaining a large meshing ratio as in the second aspect of the invention. The pinion and the ring gear of the flywheel mesh with each other to reduce the impact during rotation.

In the flywheel of the fourth aspect of the invention, the ring gear is provided integrally with the flywheel by the rolling process. When the rolling process is started, the machined teeth have effective tooth width portions.
Only biting into the rolling unit in minutes, because the entire tooth width direction including the excess portion with the progress of rolling is adapted to bite into the target rolling unit, rolling starting load There is reduced, manufacturing costs become life of the rolling die is long with energy efficiency is improved at the time of rolling is Ru are reduced.

In the effective tooth width portion of the teeth of the ring gear, the groove bottom shape between the processed teeth of the rolling die is transferred to the tooth tips of the teeth of the ring gear, whereby the first aspect of the present invention can be achieved.
Since any of the top chamfers of the third invention is provided, the ring gear having such a top chamfer can be easily and inexpensively processed as compared with the case where the ring gear is manufactured by cutting. Further, in the surplus portion other than the effective tooth width, the dimension corresponding to the toothbrushing direction of at least one of the rolled portion and the processed tooth is reduced, and a space for receiving the excess thickness of the effective tooth width portion is formed. Therefore, even if excess thickness occurs due to dimensional error of the rolled part, excessive load will not occur, damage to the rolling device etc. will be avoided, and the target tooth width in the effective tooth width part The shape is always rolled with high precision. Due to the highly accurate teeth, the impact suppressing action by the top chamfering of the first invention to the third invention is effectively obtained, and the transmission efficiency is improved to facilitate, for example, the engine starting, and the starting with less tapping sound. Sound is obtained.

Further, since the entire tooth width of the ring gear is larger than the effective tooth width meshed with the drive pinion, the impact at the time of thrusting the drive pinion and the impact during meshing rotation are dispersed and transmitted, and the tooth strength is increased. Is improved. When a ring gear is formed by rolling as in the present invention, spheroidal graphite cast iron is preferably used as the flywheel rough material, and the mechanical strength is lower than that of conventional steel. By improving the first invention,
The damage of the teeth is effectively prevented in combination with the impact suppressing effect of the top chamfering of the third invention.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Here, the present invention is preferably applied to a flywheel for a vehicle, which is attached to a crankshaft of an engine or the like and is rotatably driven by a drive pinion of a starter when the engine is started. It can also be applied to flywheels of other rotary members that are rotationally driven. As the drive pinion and the ring gear, a spur gear whose teeth are parallel to the axis is preferably used.

It is desirable that the ring gears of the flywheels of the first to third inventions are integrally provided by rolling, and in that case, high quality cast iron, especially spheroidal graphite cast iron, is suitable as the material of the flywheel rough material. Used for.
Since the rolling process has a higher degree of freedom in setting the tooth shape than the cutting process, the ring gear having the top chamfer of the first invention to the third invention can be processed easily and inexpensively.

In the top chamfering of the first tooth surface in the second invention and the third invention, the top chamfering amount on the front side (drive pinion thrust side) is at least larger than the top chamfering amount at the center portion in the tooth width direction. For example, the top chamfering amount is gradually reduced from the front side toward the opposite back side, but the top chamfering amount may be gradually increased symmetrically with respect to the center in the tooth width direction. These can be appropriately selected depending on the design requirements, but if they are changed symmetrically with respect to the center in the tooth width direction, the load applied to the teeth during mesh rotation will be symmetrical, so the teeth will be twisted. The moment disappears.

In the flywheel of the third invention, at least the first tooth surface is provided with a predetermined top chamfer, but the second tooth surface on the opposite side is also similar to the first tooth surface, that is, in the tooth width direction. It is possible to perform the top chamfering in which the top chamfering amount on the front side from which the drive pinion enters is larger than the top chamfering amount in the central portion in the tooth width direction. It is desirable that the top chamfering amount of both tooth surfaces be larger on the first tooth surface side as in the first aspect of the invention, but both tooth surfaces may be chamfered with the same size.

The flywheel of the fourth aspect of the invention is, for example, substantially disk-shaped, and has an externally toothed ring gear integrally provided on the outer periphery by rolling, and the ring gear has a direction substantially parallel to the axis. A method of manufacturing a flywheel in which a drive pinion is meshed with and is rotationally driven in a predetermined constant rotation direction, wherein (a) the ring gear of the flywheel rough material before the rolling is rolled. At least one of the rolled part to be rolled and the processing tooth of the rolling die that performs the rolling process has a dimension corresponding to the tooth rolling direction of the target ring gear that changes in the tooth width direction. And (b) when the rolling process starts, the machined teeth of the rolling die partially bite into the part to be rolled in the tooth width direction. But that It is well prepared according to the manufacturing method and a rolling step comprising a bite into the thread rolling part.

Further , in the rolling processing step , (a) in the effective tooth width portion from the end portion on the front side into which the drive pinion is projected in the tooth width direction to the intermediate portion, the processing tooth of the rolling die is While the top chamfer of any one of the first to third inventions is provided by transferring the groove bottom shape between the two to the tooth tip portion of the ring gear, (b) the back surface rather than the effective tooth width portion. The diameter of the tip circle of the surplus part on the side is smaller than the tip circle diameter of the effective tooth width part, so that the tooth of the part corresponding to the surplus part of at least one of the rolled part and the machined tooth. Reduce the dimension corresponding to the direction of bamboo,
A space for receiving the excess thickness of the effective tooth width portion is formed between the rolled portion and the processed tooth.

As the rolling die, a rolling round die or a rolling flat die is preferably used. These rolling dies have machined teeth with the same width as the target ring gear, so that the rough material (meat) of the rolled part does not escape in the axial direction. It is desirable to provide a pair of flange-shaped side walls at both ends of the teeth to close the groove between the processed teeth.

In the rolled portion of the flywheel rough material, the dimension corresponding to the tooth rolling direction of the ring gear tooth is the outer diameter of the rolled portion, and as a form in which it changes in the tooth width direction, In the case where the outer diameter of the rolled portion changes in the axial direction, the small diameter portion and the large diameter portion change with a step in the middle, when a part or the whole is inclined in a taper shape, Alternatively, there is a case where an annular groove having a predetermined depth is provided on the outer peripheral surface of the rolled portion. In the fourth invention,
For example, the diameter may be fixed in the effective tooth width portion, and may be changed with a step in the middle so that the diameter is smaller than that in the surplus portion, or the diameter may be gradually tapered.

In the machined tooth of the rolling die, the dimension corresponding to the tooth rolling direction of the ring gear tooth is the height dimension of the machined tooth, and as a form in which it changes in the tooth width direction, the height of the machined tooth is In the case of a round die, for example, in the case of a round die, if there is a step between the small diameter portion and the large diameter portion with a step in the middle, if a part or the whole is inclined in a taper shape, Alternatively, it is a case where a groove having a predetermined depth is provided so as to intersect with the processed tooth. In the case of a flat die, if the height of the machined tooth changes with a step in the middle, if the height of a part or the whole changes continuously and is inclined, or if it intersects with the machined tooth. This is the case, for example, when a groove having a predetermined depth is provided. In the fourth invention,
For example, the height of the machined tooth is constant in the effective tooth width part, and is changed in the surplus part so that it is lower than that, or it is inclined so that the height continuously decreases (in the case of a round die) Taper).

Another preferred embodiment of the flywheel will be illustrated. These are all cases in which the ring gear is integrally provided on the flywheel by rolling (hot rolling), and it is desirable to carry out it together with any of the first invention to the fourth invention, but it is carried out independently. You can also

(I) The ring gear is formed by a rolling process on a ring-shaped rolled portion integrally provided on an outer peripheral portion of a disc-shaped flywheel rough material so as to project in the axial direction. , The radial dimension of the rolled part is
The width is set to be approximately the same as or larger than the width of the ring gear. In that case, since the outer peripheral side of the flywheel is thick, the weight efficiency of the moment of inertia is good, and a large moment of inertia can be obtained within the limited diameter dimension, while the radial load is applied during the rolling process of the ring gear. Even if it is subjected to deformation, there is little deformation and it is possible to roll teeth with high accuracy. Further, if the outer diameter of the main body of the flywheel is substantially the same as the diameter of the tip circle of the ring gear, it is possible to favorably prevent the ring gear from being damaged during conveyance. Further, since the inner peripheral portion of the ring gear is thinner, the heat of the portion to be rolled is less likely to escape during the hot rolling process, so that the rolling process can be favorably performed and the heating energy can be reduced.

(Ii) In the ring gear, the front end surface of the tooth is inclined inward (back surface side) at a predetermined angle so that the tooth width becomes narrower toward the tooth tip side. In that case, the impact at the time of contact with the drive pinion is alleviated and the tooth strength is improved,
The die can be easily released from the rolling die during the rolling process, the die life is improved and the tooth accuracy is improved.

(Iii) The tooth profile of the pair of tooth surfaces of the teeth of the ring gear has a tooth tip portion with a chamfered top portion, an involute curve portion in the center, and a root portion (fillet portion) that communicates with the tooth bottom surface.
It is set so that and are connected smoothly. In this case, the impact and noise during meshing rotation with the drive pinion are reduced.

(Iv) The flywheel has a thick disk shape, and the ring gear is integrally provided on the outer periphery of the flywheel by a rolling process, and the inner periphery of the ring gear has a shaft. An annular slit is formed from one end side (front side or back side) in the direction. In this case, the presence of the slits hinders the heat conduction from the rolled part, so that the heat of the rolled part is difficult to escape during the hot rolling process as in the case of (i) above. It can be satisfactorily performed and the heating energy can be reduced.

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are a longitudinal sectional view and a front view of a flywheel 10 for a vehicle which is an embodiment of the present invention, and the longitudinal sectional view of FIG. 1 is a view corresponding to a II section in FIG. . As shown in FIG. 3, the flywheel 10 is attached to a crankshaft of an engine 12 that operates by combustion of fuel and is rotated integrally with the crankshaft, so that the rotation fluctuation of the crankshaft caused by the torque fluctuation caused by the explosion is caused. Suppress. Further, a ring gear 14 having external teeth is integrally provided on the outer peripheral portion on the front side of the flywheel 10, and is meshed with a drive pinion 18 of a starter 16 for starting the engine 12, and the drive pinion 18 is When the flywheel 10 is rotated in the arrow A direction, the flywheel 10 is rotationally driven in the arrow B direction, that is, clockwise, and the crankshaft is rotationally driven (cranking). The drive pinion 18 is arranged so as to be movable in a direction parallel to the axis O of the flywheel 10. When the engine 12 is started, the drive pinion 18 approaches the ring gear 14 from the front side of the flywheel 10 and meshes with the ring gear 14. While being moved up to, it is normally held in the standby position where the engagement with the ring gear 14 is released. FIG. 3 shows a state in which the drive pinion 18 is moved to the meshing position.

The flywheel 10 has a substantially disc shape, and is integrally and concentrically fixed to the crankshaft by bolts or the like through a plurality of (six in the figure) mounting holes 20 provided near the central portion. To be done. Main body 2 of this flywheel 10
Although 2 is relatively thin, the ring gear 14 is integrally provided in parallel with the main body portion 22 so as to project in the outer peripheral portion in the axial direction, and the outer peripheral portion of the flywheel 10 is thick. As described above, since the outer peripheral portion of the flywheel 10 is thick, the weight efficiency of the moment of inertia is good, and a large moment of inertia can be obtained within a limited diameter dimension.

The flywheel 10 is made of spheroidal graphite cast iron, and the ring gear 14 is integrally formed by hot rolling. However, as shown in FIG. The radial dimension D of the rolled portion 23 (after the rolling processing) that has been rolled is determined by the ring gear 14
The tooth width is larger than the tooth width dimension W. Therefore, even if a radial load is applied during the rolling process of the ring gear 14, the deformation is small and the tooth can be processed with high precision. The outer diameter of the main body portion 22 of the flywheel 10 is substantially the same as the tip circle diameter of the ring gear 14,
While the flaws such as 4 are favorably prevented, the rolled portion 23
Since the inner peripheral portion is thinner than the inner peripheral portion, the heat of the rolled portion 23 does not easily escape during the hot rolling process, so that the rolling process can be favorably performed and the heating energy can be reduced. Figure 4
(B) is a cross-sectional view of an outer peripheral side portion where the ring gear 14 is provided, and (a) is a plan view (developed view) of the ring gear 14 viewed from the outer peripheral side.

The ring gear 14 is composed of a spur gear whose teeth are parallel to the axis O, and has a large number of teeth 24 parallel to the axis O. The teeth 24 are shown in FIG.
As is apparent from (a) and (b) showing a bb cross section thereof, the first of the pair of tooth flanks 26, 28 to which motion is transmitted when being rotationally driven by the drive pinion 18
A chamfer 30 is provided on the front side corner portion of the second tooth surface 28 opposite to the tooth surface 26. When the drive pinion 18 is moved to the meshing position, the chamfer 30 guides the chamfer 30 and is good with the ring gear 14. It is designed to be meshed with. When the drive pinion 18 contacts the front end surface 32 of the tooth 24, the drive pinion 18 is pressed against the end surface 32 by the urging force of a spring or the like, and then the starter 16 is pressed.
When it is driven to rotate by the ring gear 14, it meshes with the ring gear 14, but the end face 32 is inclined inward (back side) at a predetermined angle θ (about 4 ° in the embodiment) so that the tooth width becomes narrower toward the tooth tip 34 side. Therefore, the impact at the time of contact with the drive pinion 18 is mitigated, and the tooth strength is improved. Also, since it is easy to remove the die from the rolling die during rolling,
The die life is improved and the accuracy of the teeth 24 is improved.

The tooth 24 also has a complete tooth portion 24 having the desired complete tooth profile, as shown in FIG. 4 (b).
a and a toothless portion 24b in which the tooth tip 34 is missing,
The complete tooth portion 24a is engaged with the drive pinion 18. That is, the complete tooth portion 24a is provided at least in the range from the end portion on the front side to the predetermined intermediate position corresponding to the effective tooth width. The part 24b corresponds to a surplus part.

FIG. 6 is a cross-sectional view of the complete tooth portion 24a at right angles to the axis O. A pair of tooth surfaces 26, 28 are top-chamfered (topping).
a, 28a and central involute curve portions 26b, 2
8b and root portions (fillet portions) 26c, 2 that communicate with the tooth bottom surface
And 8c. Tooth tip portion 26 of the first tooth surface 26
The width dimension of a in the toothbrushing direction (vertical direction in FIG. 6), that is, the top chamfering width is set to be larger than the top chamfering width of the second tooth surface 28, and the involute curve portion 28b of the second tooth surface 28 is formed. Is longer than that by the involute curve portion 26b of the first tooth surface 26. Further, these tooth tips 26a, 28a, the involute curve portion 26b,
28b and the root portions 26c, 28c are connected by smooth R, respectively, so that the impact and noise at the time of meshing rotation with the drive pinion 18 are reduced.
In this embodiment, since the ring gear 14 is formed by the rolling process, the degree of freedom in setting the shape of the tooth 24 is high, and the above tooth profile can be easily processed.

Since the top chamfer of the first tooth surface 26 is large as described above, the impact when the drive pinion 18 is engaged in the direction parallel to the shaft center O is alleviated, and abnormal noise and teeth 2 are generated.
The damage of No. 4 and the shortening of life due to fatigue are suppressed. That is, when the drive pinion 18 comes into contact with the front end surface 32 of the tooth 24 when the drive pinion 18 is moved to the meshing position, it meshes with the ring gear 14 when it is rotationally driven by the starter 16, and at that time, the drive pinion 18 The teeth of the collide with the first tooth surface 26, but the impact at that time is preferably mitigated by the relatively large top chamfer. Further, since the top chamfer of the second tooth surface 28 on the opposite side is small and the involute curve portion 28b is lengthened by that much,
The meshing ratio on the tooth surface 28 side is increased, rotation fluctuation due to shoulder contact of the edge of the tooth tip 34, etc. is suppressed, and the impact during meshing rotation is reduced. That is, the first tooth surface 26
Since the top chamfering amount of the drive pinion 18 is made larger than the top chamfering amount of the second tooth surface 28, the impact at the time of the drive pinion 18 plunging is suppressed while suppressing the increase in the impact during the meshing rotation of the drive pinion 18 and the ring gear 14. You can do it.

The top chamfer is formed by the first tooth surface 26 side and the second tooth surface 26 side.
On the tooth surface 28 side, at least the entire tooth width of the complete tooth portion 24a may be applied with a constant width dimension, but since the degree of freedom in setting the tooth shape is high, it is shown in FIG. 7 in this embodiment. As described above, as for the top chamfer on the side of the first tooth surface 26, the chamfer width is increased toward the front side from which the drive pinion 18 enters, that is, the end surface 32 side. In FIG. 7, the portions shown by hatching (dots) are the top chamfered portions (tooth tips 26a, 28a), and the second tooth surface 28
The chamfer width e of the tooth tip portion 28a on the side is constant in the tooth width direction, but regarding the tooth tip portion 26a on the first tooth surface 26 side,
Back side (boundary portion between the complete tooth portion 24a and the toothless portion 24b)
The chamfer width d is substantially the same as the chamfer width e, and is gradually increased toward the front side, and the chamfer width c at the front end is sufficiently larger than the chamfer widths d and e. Note that, in FIG. 7, the toothless portion 24 b on the back surface side of the tooth 24 and the chamfer 30 on the front surface side of the second tooth surface 28 are omitted.
The same applies to FIG. 8 described later.

That is, when the drive pinion 18 rushes into rotation and meshes with the ring gear 14, the teeth of the drive pinion 18 contact only the front side portion of the first tooth surface 26. The amount of chamfering on the front side was made larger than that of other parts. With this configuration, it is possible to reduce the impact of the drive pinion 18 when the drive pinion 18 rushes, while maintaining a large meshing ratio of the first tooth surface 26.
Compared with the case where the top chamfering amount on the first tooth surface 26 side is increased over the entire tooth width, even at the time of meshing rotation in which power is transmitted from the drive pinion 18 side to the flywheel 10, the edges of the tooth tips 34 and the like are Rotational fluctuation due to shoulder contact is suppressed,
The impact during the mesh rotation is reduced.

FIG. 8 is a view showing another form of the top chamfer (tooth tip portion 26a) of the first tooth surface 26. FIG. 8 (a) shows the chamfer width d on the back surface side on the second tooth surface 28 side. The width is smaller than the width e, and the effect of alleviating the impact force when the drive pinion 18 plunges is slightly reduced, but the engagement rate of the first tooth flank 26 is further increased, so that impact and noise during engagement rotation are generated. It is further reduced. (b) is a case where the top chamfering amount is gradually increased substantially symmetrically with the center in the tooth width direction as a boundary, and the chamfering width f at the center is substantially the same as or smaller than the chamfering width e,
The chamfer widths c and d on both sides are substantially the same and are sufficiently larger than the chamfer width e. In this case, the load applied to the tooth 24 during the meshing rotation is symmetrical with respect to the center in the tooth width direction on both the first tooth surface 26 side and the second tooth surface 28 side. Disappears. The form of such a top chamfer is appropriately selected according to requirements at the time of design.

Next, a rolling die for rolling the ring gear 14 of the flywheel 10 and a flywheel rough material before rolling will be described.

FIG. 9 is a perspective view showing a rolling round die 40 which is preferably used for rolling the ring gear 14 and a flywheel rough material 42 before the ring gear 14 is rolled. The outer circumference of the rolled round die 40 has the same width dimension as the tooth width dimension W of the ring gear 14 (length dimension in the axial direction).
In addition, a large number of machining teeth 44 are radially provided, and at both ends of the machining tooth 44, adjacent machining teeth 44 are formed.
A pair of flange-shaped side walls 46 and 48 are integrally provided to close the groove between them and prevent the outflow of the rough material (meat).
The outer diameters of the side walls 46 and 48 are larger than the outer diameter of the processing tooth 44, and protrude to the outer peripheral side.

FIG. 10A is a sectional view of the outer peripheral portion of the rolled round die 40. The height dimension (radial dimension) of the machined tooth 44 is the complete tooth portion 24a of the tooth 24 of the ring gear 14. The groove cross-sectional shape including the groove bottom between the adjacent processed teeth 44 is the same as that of the toothbrush in FIG.
a, 28a) corresponding to the tooth shape of the complete tooth portion 24a. Although the width dimension of the machined tooth 44 is the same as the tooth width dimension W and is longer than the complete tooth portion 24a by the missing tooth portion 24b, the groove shape of the side wall 48 side portion corresponding to the missing tooth portion 24b also has the complete tooth portion 24a. It has a shape corresponding to the tooth shape of. Further, the inner wall surface of the one side wall 46 is inclined at a predetermined angle θ corresponding to the front end surface 30 of the tooth 24.

The flywheel rough material 42 is formed by integrally forming a rolled portion (before rolling) 50 on which the ring gear 14 is to be rolled on the disk-shaped main body portion 22. 10B is a cross-sectional view of the outer peripheral portion of the flywheel rough material 42. The rolled portion 50 has the same width dimension (axial length dimension) as the tooth width dimension W, and the ring gear 14 The outer diameter dimension of the tooth 24 corresponding to the toothbrush direction is changed stepwise in the axial direction, and is divided into a large diameter portion 50a having a large outer diameter and a small diameter portion 50b having a small outer diameter. The large diameter portion 50a is a portion corresponding to the complete tooth portion 24a, and has a width dimension substantially the same as the effective tooth width that meshes with the drive pinion 18, and the outer diameter dimension thereof is set by cutting into the machining tooth 44. It is determined that the extruded rough material fills the groove portions between the processing teeth 44 and is formed into a tooth shape corresponding to the groove shape. In the step of preparing such a flywheel rough material 42, the dimension corresponding to the toothbrushing direction of the target tooth 24 of the ring gear 14, that is, the outer diameter dimension changing in the tooth width direction (axial direction) This corresponds to the step of preparing.

The flywheel rough material 42 and the rolled round die 40 are rotatably arranged around axes parallel to each other with a predetermined distance between the axes. For example, the rolled round die 40. While rotating the shaft around the axis, the two are relatively brought close to each other to press the machining tooth 44 against the outer peripheral surface of the rolled portion 50 of the flywheel rough material 42. Figure 1
(A) of 1 corresponds to the time when the rolling process is started in a state where the tooth tips of the machined teeth 44 are in contact with the outer peripheral surface of the large diameter part 50a of the rolled part 50. After that, the two are brought closer to each other and the flywheel rough material 42 is rotated together, and the machining teeth 44 are bitten into the outer peripheral surface of the rolled portion 50.
As shown in 1 (b), the machined tooth 44 is completely rolled 50
In the large diameter portion 50a, the complete tooth portion 24a corresponding to the groove shape is rolled. Processed tooth 4 in small diameter part 50b
Since the biting dimension of 4 is small, the swelling of the rough material is small, the space 52 remains between the processed teeth 44 and the groove bottom, and the toothless portion 24b in which the tooth tip 34 is missing is formed. This means that when the rolling process is started, the machining teeth 44 of the rolling round die 40 partially bite into the part 50 to be rolled in the tooth width direction, specifically, only bite into the large-diameter part 50a. This is a rolling process step in which the entire tooth width direction bites into the rolled portion 50 as it advances. The alternate long and short dash line in FIG. 11 (b) is the initial shape of the rolled portion 50. During the rolling process, the flywheel rough material 42 is heat-treated by a predetermined heating device. The rolling direction of the rolled round die 40 is, for example, the flywheel 1
0 is set so that the flywheel rough material 42 rotates in the same direction as the rotation direction in which the drive pinion 18 rotates.

Here, at the start of the rolling process of FIG. 11 (a), the machining teeth 44 only bite into a part of the rolled part 50, that is, the large diameter part 50a, and the width increases as the rolling process progresses. Since the entire direction cuts into the rolled portion 50, the load at the start of rolling processing is reduced, the energy efficiency during rolling processing is improved, and the life of the rolling round die 40 becomes longer. Manufacturing costs are reduced.

On the other hand, in the large diameter portion 50a, the rolled round die 4
The groove bottom shape between the processing teeth 44 of 0 is the tooth 2 of the ring gear 14.
By being transferred to the tooth tip portion of No. 4, the complete tooth portion 24a having the top chamfer (tooth tips 26a, 28a) and the like.
Since the ring gear 14 is rolled, the ring gear 14 having such a top chamfer can be processed easily and inexpensively as compared with the case where the ring gear 14 is manufactured by cutting.

Further, in this embodiment, the width dimension (tooth width dimension W) of the rolled portion 50 is longer than the effective tooth width engaging with the drive pinion 18, and the portion longer than the effective tooth width portion is the small diameter portion 5.
Since the space 52 is formed between the rolling round die 40 and the rolling round die 40 at the time of rolling processing, even if a surplus is generated due to a dimensional error of the rolled portion 50, it is excessive. The load is not generated, damage to the rolling device is avoided, and the large-diameter portion 50a has the perfect tooth portion 24 having the desired tooth shape.
a is always rolled with high accuracy. Due to the highly accurate complete tooth portion 24a, the top chamfering (tooth tips 26a, 2
In addition to the effect of suppressing the shock by 8a) being effectively obtained, the transmission efficiency is improved to facilitate the starting of the engine 12, and a starting sound with less tapping sound is obtained.

The diameter of the small diameter portion 50b is the same as that of the rolled portion 5.
The space 52 is determined to remain regardless of the dimensional error of 0, and the larger the step with the large diameter portion 50a, the larger the space 52 can be secured.

Further, the overall tooth width dimension W of the ring gear 14
Is larger than the effective tooth width that meshes with the drive pinion 18, the impact when the drive pinion 18 rushes in and the impact during the meshing rotation are distributed and transmitted, and the tooth strength is improved. The flywheel 10 of this embodiment is made of spheroidal graphite cast iron and has a lower mechanical strength than conventional steel, but the chamfered top (tooth tip) is improved by improving the tooth strength as described above. The damage of the teeth 24 is effectively prevented in combination with the impact suppressing action of the portions 26a, 28a).

In the above embodiment, the stepped portion 50 of the flywheel rough material 42 is provided with a step, but it may be inclined instead of stepped. Further, as shown in FIG. 12, a step may be provided on the processing tooth 62 of the rolled round die 60. As shown in FIG. 13A, the machined tooth 62 includes a high tooth portion 62a having a width dimension corresponding to the complete tooth portion 24a and a low tooth portion 62b having a width dimension corresponding to the toothless portion 24b. The height dimension of the high tooth portion 62a is the same as the height dimension of the machined tooth 44, but the height dimension (outer diameter dimension) of the low tooth portion 62b is lower than that. On the other hand, flywheel rough material 66
Is the width dimension (tooth width dimension W) as shown in FIG. 13 (b).
The rolled portion 68 having the same diameter as that of the large diameter portion 50a is provided over the entire area.

In this case as well, the flywheel rough material 66 and the rolled round die 60 are rotatably arranged about the axes parallel to each other with a predetermined distance between the axes, and as shown in FIG. One of them is relatively driven while rotating one about the axis to move the machining tooth 62 to the flywheel rough material 66.
By biting into the outer peripheral surface of the rolled portion 68, the tooth 70 similar to the tooth 24 is rolled. Of FIG.
In (a), the tooth tip of the high tooth portion 62a of the processed tooth 62 is the rolled portion 5
This corresponds to the start of the rolling process in a state of being brought into contact with the outer peripheral surface of the large diameter portion 50a of 0. FIG. 14B shows the processed tooth 6
2 completely bites into the rolled portion 68 including the low tooth portion 62b, and in the state where the rolling process is substantially completed, the high tooth portion 62a is completely rolled to form the complete tooth portion 70a corresponding to the groove shape. In the low tooth portion 62b, the space 7 is formed in the groove bottom portion between the processing teeth 62.
2 is left, and a toothless portion 70b in which the tooth tip 34 is missing is formed. The complete tooth portion 70a corresponds to the complete tooth portion 24a, and the toothless portion 70b corresponds to the toothless portion 24b.
Corresponding to the tip shape of the machined tooth 62, the tooth bottom surface of the toothless portion 70b is higher (larger diameter) than the tooth bottom surface of the complete tooth portion 70a. Note that the alternate long and short dash line in FIG. 14B is the initial shape of the rolled portion 68.

The flywheel rough material 80 of FIG. 15 is rolled by the rolling round die 40 of FIG. 9, and the toothless portion 24b (excess portion) is formed in the rolled portion 82.
The end portion 82a on the side corresponding to is cut out in a tapered shape, and an annular groove 82b is formed in a portion corresponding to the complete tooth portion 24a (effective tooth width portion). Also in this case, the biting length of the processed tooth 44 at the start of the rolling process is the end portion 8
It is shortened by the lack of 2a and the groove 82b, and the load at the start of rolling is reduced. Also, the missing of them and the groove 8
Only the volume of 2b can absorb the surplus due to dimensional errors. The groove 82b reduces the load at the start of rolling without damaging the tooth shape of the ring gear even when the tooth width of the ring gear is set to be substantially the same as the effective tooth width that meshes with the drive pinion 18. It is effective in absorbing meat.

In the flywheel 84 of FIG. 16, the ring gear 14 similar to that of the flywheel 10 is formed on the outer peripheral portion of the rolled portion (after the rolling processing) 86 by the rolling processing. In addition to forming the disc shape of
An inner peripheral portion of the ring gear 14, for example, the radial dimension D
A slit 88 is formed in an annular shape at a portion substantially inward of the same dimension as the above from the end surface on the front side substantially parallel to the axis.
In this case, the presence of the slits 88 hinders the heat conduction from the rolled portion 86, so that the ring gear 14 is hot rolled during the hot rolling process, like the flywheel 10 having a thin inner peripheral portion. The heat of the rolled portion 86 is hard to escape, and the rolling process can be favorably performed and the heating energy can be reduced.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above embodiment, the rolled round die 4
0, 60 and the flywheel rough materials 42, 66, 80 were made to be relatively close to each other, but the rolling round is sufficiently larger than the flywheel rough materials 42, 66, 80. When performing rolling using a die,
By providing the biting portion like a normal rolling round die, both can be positioned at positions separated by a predetermined inter-axis distance to perform the rolling process. It is also possible to adopt other rolling dies such as a rolling flat die instead of the rolling round die.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vehicle flywheel that is an embodiment of the present invention.

FIG. 2 is a front view of the flywheel of FIG.

FIG. 3 is a schematic perspective view showing a state in which the flywheel of FIG. 1 is arranged on a crankshaft of an engine.

4 is an enlarged view showing a ring gear portion of the flywheel of FIG. 1, (a) is a plan view seen from the outer peripheral side, and (b) is a sectional view.

5 is a diagram illustrating the ring gear of FIG. 4 in detail, (a)
Is a front view and (b) is a sectional view taken along line bb in (a).

6 is a cross-sectional view of one tooth of the ring gear of FIG.

FIG. 7 is a diagram illustrating a top chamfer provided on a tooth surface of a ring gear.

FIG. 8 is a diagram illustrating another aspect of top chamfering provided on the tooth surface of the ring gear.

9 is a schematic perspective view showing a flywheel rough material for manufacturing the flywheel of FIG. 1 and a rolled round die for rolling a ring gear.

10 is a cross-sectional view of essential parts of the flywheel rough material and the rolled round die of FIG. 9.

FIG. 11 is a diagram illustrating a process when a ring gear is rolled on a flywheel rough material by the rolling round die of FIG. 9;

FIG. 12 is a schematic perspective view showing a flywheel rough material and a rolled round die different from those in FIG. 9.

13 is a cross-sectional view of main parts of the flywheel rough material and the rolled round die of FIG.

FIG. 14 is a diagram illustrating a process when a ring gear is rolled on a flywheel rough material by the rolling round die of FIG. 12;

FIG. 15 is a view for explaining another embodiment of the flywheel rough material, and is a cross-sectional view near the portion to be rolled.

FIG. 16 is a view for explaining another embodiment of the flywheel and is a cross-sectional view near the ring gear.

[Explanation of symbols]

10,84: Flywheel 14: Ring gear 18: Drive pinion 24, 70: Tooth 24a, 70a: Complete tooth portion (effective tooth width portion) 24b, 70b: missing tooth part (excess part) 26: First tooth surface 26a: Tip portion (top chamfer) 28: Second tooth surface 28a: tooth tip (chamfered top) 40, 60: Rolling die (rolling die) 42,66,80: Flywheel rough material 44, 62: Processed tooth 50, 68, 82: Rolled part 52, 72: space O: axis

Front Page Continuation (72) Inventor Shinichi Ito 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (56) References JP 62-68642 (JP, A) SAI 63-45441 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16F 15/30 F16H 55/17

Claims (4)

(57) [Claims] 1. A ring gear having a substantially disk shape and having external teeth is integrally provided on an outer peripheral portion thereof, and a drive pinion is meshed with the ring gear in a direction substantially parallel to an axis, and the ring gear is predetermined. A pair of tooth flanks of the ring gear, the top chamfering amount of the first tooth flank to which the motion is transmitted when being rotationally driven by the drive pinion. The flywheel is characterized in that it is larger than the top chamfering amount of the second tooth surface on the opposite side. 2. The front chamfering amount of the first tooth surface on the front side where the drive pinion is projected in the tooth width direction is more than the top chamfering amount of the central portion in the tooth width direction. A flywheel characterized by being enlarged. 3. A ring-shaped gear having a substantially disk shape and having external teeth integrally provided on an outer peripheral portion thereof, and a drive pinion is meshed with the ring gear in a direction substantially parallel to an axis, and the ring gear is predetermined. And a top chamfer on at least a first tooth surface of the pair of tooth surfaces of the ring gear to which motion is transmitted when rotationally driven by the drive pinion. A flywheel characterized in that the front chamfering amount on the front side where the drive pinion projects in the tooth width direction is larger than the top chamfering amount in the central portion in the tooth width direction. 4. A substantially circular plate shape and a rolling process
A ring gear with external teeth is integrally provided on the outer peripheral part by
Drive ring from the direction substantially parallel to the axis of the ring gear.
The unions mesh with each other and move in a predetermined constant rotation direction.
A flywheel that is rotationally driven, wherein the teeth of the ring gear have an effective tooth width that meshes with the drive pinion from an end on the front side into which the drive pinion enters in the tooth width direction to an intermediate portion. In the tooth width portion, the groove bottom shape between the processing teeth of the rolling die for performing the rolling processing is transferred to the tooth tip portions of the teeth of the ring gear, whereby any one of claims 1 to 3 is obtained. While the above-described top chamfer is provided, the rolling process is performed so that the diameter of the tip circle of the surplus portion on the back surface side of the effective tooth width portion is smaller than the diameter of the tip circle of the effective tooth width portion. The previous flywheel rough material
And a rolling die in which the rolling gear is rolled
At least one of the portions corresponding to the excess portion of the forming teeth of the scan is small dimensions corresponding to the tooth depth direction of the tooth of the ring gear of interest, the rolling start machining teeth of the rolling die Said effective
Rolling can be done by simply biting into the part to be rolled at the tooth width part.
As the machining progresses, the entire tooth width direction including the surplus part
Will start to bite into the part to be rolled, and
The tip circle diameter of the gear is small at the surplus part.
In the flywheel, a space for receiving the excess thickness of the effective tooth width portion is formed between the rolled portion and the processed tooth.