JPH0882345A - Flywheel device for internal combustion engine - Google Patents

Abstract

PURPOSE: To reduce the number of part items and assembling manhours and simultaneously to improve the fatigue strength of a boundary between a mounting flange part and an elastic deformation part and to improve hardness of the slide surface of an oil seal. CONSTITUTION: A mass part 11, a mounting flange part 13, and a plate part 15 are integrally molded with each other, and a cylinder part 16 extending concentrically with the axis of a crankshaft 12 is molded integrally with a connection part between the mounting flange part 13 and the elastic deformation part 14 of the plate part 15. The inner peripheral surface of the cylinder part 16 is fitted in the outer peripheral surface of the flange part 12A of the crankshaft 12, and the inner peripheral surface of an oil seal 21 fixed to a cylinder block 20 is slidably fitted to the outer peripheral surface of the flange part 12A. Surface treatment 22, for example, high frequency quenching treatment or nitriding treatment, to improve fatigue strength is applied to the outer peripheral surface 16A of the cylinder part 16 and the surface of a rounded part 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flywheel device for an internal combustion engine, and more particularly to a technique for reducing the number of parts and the number of assembling steps.

[0002]

2. Description of the Related Art As a conventional flywheel device for an internal combustion engine, there is a flywheel device as shown in FIG. 3 (see Nissan New Model Manual 1992, page B-12). This flywheel device has a structure for reducing bending vibration, and includes a mass portion 1, a mounting flange portion 2, and a plate-shaped elastically deforming portion 3 for allowing bending displacement between the mass portion 1 and the mounting flange portion 2. The mass portion 1 is fastened to the elastically deformable portion 3 by the bolt 4, and the mounting flange portion 2 is fastened to the end surface of the crankshaft 6 by the bolt 5 via the elastically deformable portion 3.

There is also a conventional flywheel device for an internal combustion engine as shown in FIG. 4 (see Nissan CA engine maintenance manual, 1985, p. 12). That is, in this one, the flange portion 7A at the end of the crankshaft 7
The outer peripheral surface is subjected to surface hardening treatment such as induction hardening and grinding, so that the inner peripheral surface of the ring-shaped oil seal 9 fixed to the cylinder block 8 can be slid with respect to the outer peripheral surface of the flange portion 7A. I am trying to assemble it.

[0004]

However, in such a conventional flywheel device for an internal combustion engine,
Each had the following problems. That is, in the flywheel device of FIG. 3, the mass portion 1 and the mounting flange portion 2
Since the elastically deforming portion 3 is a separate body, the number of parts and the number of assembling steps increase, which is disadvantageous in terms of cost.

Therefore, the mass portion 1 and the mounting flange portion 2
It is conceivable that the elastically deformable portion 3 and the elastically deformable portion 3 are integrated. In integrally forming the mass portion 1, the mounting flange portion 2, and the elastically deformable portion 3, the elastically deformable portion 3 includes the mass portion 1 and the mounting flange portion so as to allow the plate surface bending of the elastically deformable portion 3. 2, it is necessary to have a sufficiently low rigidity, and the requirements for material properties of the mass portion 1 and the mounting flange portion 2 and the elastically deforming portion 3 are naturally different.

[0006] In consideration of such requirements of material characteristics, when the mass portion 1, the mounting flange portion 2 and the elastically deforming portion 3 are integrally structured, the boundary portion between the mounting flange portion 2 and the elastically deforming portion 3 is formed. In fact, it is unavoidable that a stress concentration portion occurs, and it is difficult to form the integrated structure. Further, in the flywheel device of FIG. 4, since the crankshaft 7 is provided with the sliding surface 7A of the oil seal 9, the oil seal 9 is likely to receive heat transfer due to heat generation in the bearing of the crankshaft 7, There is a problem that the heat load on the oil seal 9 increases, and it is necessary to raise the heat resistant temperature condition of the oil seal 9.

In view of the conventional problems as described above, the present invention provides a flywheel device for an internal combustion engine in which a mass portion, a mounting flange portion, an elastically deformable portion, and a sliding surface of an oil seal are provided. By integrating and with
To improve the fatigue strength at the boundary between the mounting flange and the elastically deformable part and the hardness of the sliding surface of the oil seal, which is necessary to achieve this integrated structure by reducing the number of parts and the number of assembly steps. The purpose is to plan.

[0008]

Therefore, according to the first aspect of the present invention, there is provided a mass portion located at an outer peripheral portion and a mounting flange portion located at a central portion and serving as a mounting portion to a flange portion of a crankshaft. A plate portion that connects the mass portion and the mounting flange and has an elastically deformable portion for allowing bending displacement between the mass portion and the mounting flange at the joint portion with the mounting flange portion. In the flywheel device for an internal combustion engine, the mass portion, the mounting flange portion, and the plate portion are integrally molded, while the connecting portion between the mounting flange portion and the elastically deforming portion of the plate portion is provided with the crankshaft shaft. A cylindrical portion that extends concentrically, the inner peripheral surface of which is fitted to the outer peripheral surface of the flange portion of the crankshaft, and the inner peripheral surface of the oil seal fixed to the engine body can slide on the outer peripheral surface. The cylindrical portion to be mounted is integrally molded, and the outer peripheral surface of the cylindrical portion, the elastically deforming portion of the plate portion, and the inner corner surface of the boundary portion between the cylindrical portion are subjected to surface treatment for improving fatigue strength and hardness. .

According to a second aspect of the present invention, the inner corner surface of the boundary portion on one side of the connecting portion between the elastic deformation portion and the portion other than the elastic deformation portion of the plate portion, and the connection between the elastic deformation portion and the cylindrical portion. The inner corner surfaces of the boundary portions on both sides of the portion are respectively formed in the R portion having a predetermined radius of curvature. The invention according to claim 3 is
A disc-shaped packing is provided on the fastening surface between the mounting flange portion and the crankshaft flange portion.

According to a fourth aspect of the present invention, a groove is formed on the entire corner of the outer periphery of the tip end of the flange portion of the crankshaft, and when the flywheel device is attached to the crankshaft, the inner surface of the groove and the flange portion are formed. The ring-shaped space formed between the outer peripheral surface and the inner surface of the boundary between the end surfaces is filled with the hardening liquid packing.

[0011]

According to the present invention, the crank system bending vibration applied to the flywheel device is reduced by the effect of separating the mass portion by supporting the mass portion by the elastically deforming portion of the plate portion. Here, the R portion at the boundary between the low-rigidity elastically deformed portion and the cylindrical portion becomes strict with respect to the stress concentration applied thereto and is inferior in fatigue strength, so it is necessary to increase the fatigue strength.

Further, the oil seal sliding surface on the outer peripheral surface of the cylindrical portion needs to have high hardness from the viewpoint of wear and surface properties. In this regard, in the configuration of the flywheel device according to the first aspect of the present invention, the mass portion, the mounting flange portion, the elastically deforming portion, and the portion that becomes the sliding surface of the oil seal are integrally structured, While reducing the number of parts, the number of assembly steps, etc., the fatigue strength and hardness of the induction hardening process or the chipping process, etc. on the inner peripheral surface of the boundary between the outer peripheral surface of the cylindrical portion and the elastically deformed portion of the plate portion and the cylindrical portion, respectively. Since the surface treatment is performed for the purpose of improvement, the fatigue strength becomes high and the hardness becomes high at the same time, so that the above requirements can be satisfied.

Furthermore, since the sliding surface of the oil seal is provided on the cylindrical portion which is the sliding surface of the oil seal, the oil seal is less likely to receive heat transfer due to the heat generated by the bearing of the crankshaft, and thus the oil seal is not easily transferred to the oil seal. The heat load of the oil seal can be reduced, and the heat resistant temperature condition of the oil seal can be reduced.
According to the second aspect of the present invention, stress concentration is relieved at the connecting portion between the elastic deforming portion and the portion other than the elastic deforming portion of the plate portion and the connecting portion between the elastic deforming portion and the cylindrical portion.

According to the third aspect of the invention, the lubricating oil leaking from between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the flange portion is sealed by the packing. In the invention of claim 4, after applying the liquid packing to the inner surface of the groove, the flywheel device is attached to the crankshaft. After that, the packing hardens, and the lubricating oil leaked from between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the flange portion is sealed by the packing.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 showing an embodiment of the invention described in claims 1 to 3.
In the flywheel device 10, the mass portion 11 located on the outer peripheral portion and the crankshaft 1 located on the central portion
2 is attached to the flange portion 12A, the mass flange portion 11 and the attachment flange portion 13 are connected to each other, and the elastic deformation portion 14 is connected to the attachment flange portion 13.
And a plate portion 15 having a.

Here, the mass portion 11, the mounting flange portion 13 and the plate portion 15 are integrally formed. Further, a cylindrical portion 16 extending concentrically with the central axis of the crankshaft 12 is integrally formed at a connecting portion between the mounting flange portion 13 and the elastically deforming portion 14 of the plate portion 15.

The mass portion 11, the mounting flange portion 13, and the plate portion 15 are each formed in a ring shape, and the mass portion 1
The outer peripheral end of the plate portion 15 is connected to the inner peripheral surface of 1, and the outer peripheral end of the mounting flange portion 13 is connected to the inner peripheral end of the plate portion 15 via the cylindrical portion 16. The elastic deformation portion 14
Is a portion 15A other than the elastically deforming portion 14 of the plate portion 15.
It is formed in a plate shape thinner than that. in this case,
The inner corner surface of the boundary portion on one side of the connecting portion between the elastic deformation portion 14 and the portion 15A of the plate portion 15 other than the elastic deformation portion 14 is formed as an R portion 17 having a predetermined radius of curvature. Also, the elastically deformable portion 1
The inner corner surfaces of the boundary portions on both sides of the connecting portion of 4 and the cylindrical portion 16 are formed into R portions 18 and 19 having a predetermined radius of curvature, respectively. In this case, the R portion 18 is formed to have a predetermined radius of curvature smaller than that of the R portion 19.

The inner peripheral surface of the cylindrical portion 16 is fitted to the outer peripheral surface of the flange portion 12A of the crankshaft 12, and the inner peripheral surface of the oil seal 21 fixed to the engine body side, that is, the cylinder block 20, is attached to the outer peripheral surface thereof. The surface is slidably mounted. The outer peripheral surface 16A of the cylindrical portion 16 and the surface of the R portion 18 are respectively subjected to surface treatment 22 for improving fatigue strength, for example, induction hardening treatment or nitriding treatment. Further, the surface of the surface treatment 22 of the cylindrical portion 16 is ground and finished.

The flywheel device 10 having the above structure is
The mounting flange portion 13 is attached by fastening the mounting flange portion 13 to the end surface of the flange portion 12A of the crankshaft 12 with a bolt 23, and the mounting flange portion 13 and the flange portion 12 are attached.
A disc-shaped packing 24 is provided on the fastening surface with A.
In the mounted state of the flywheel device 10, as described above, the inner peripheral surface 16B of the cylindrical portion 16 is fitted to the outer peripheral surface 12B of the flange portion 12A, and the outer peripheral surface 16A of the cylindrical portion 16 is provided with the oil seal 21. The inner peripheral surface is slidably mounted.

Next, the flywheel device 1 having such a configuration.
The operation of 0 will be described. The crank system bending vibration applied to the flywheel device 10 is caused by the mass portion 11 supported by the elastically deforming portion 14 of the plate portion 15.
It is reduced by the separation effect of. Here, by setting the radius of curvature of the R portion 18 to be smaller than that of the R portion 19 at the boundary between the low-rigidity elastically deforming portion 14 and the cylindrical portion 16,
Since the R portion 18 becomes stricter with respect to stress concentration applied thereto and is inferior in fatigue strength, it is necessary to increase fatigue strength.

Further, the oil seal sliding surface of the outer peripheral surface 16A of the cylindrical portion 16 needs to have a high hardness from the viewpoint of wear and surface properties. In this respect, the flywheel device 1 described above
In the configuration of 0, the mass portion 11 and the mounting flange portion 1
3, the elastically deforming portion 14, and the portion (cylindrical portion 16) that serves as the sliding surface of the oil seal, are integrally formed, so that the outer peripheral surface of the cylindrical portion 16 can be reduced while reducing the number of parts and the number of assembly steps. 16A, the inner corner surface of the boundary between the elastically deformable portion 14 of the plate portion 15 and the cylindrical portion 16, that is, the R portion 18, is subjected to the induction hardening treatment or the chipping treatment at the same time. The hardness becomes high at the same time, and the above requirements can be satisfied.

Regarding the elastically deformable portion 14, the cylindrical portion 1
It must be designed to have a strength that does not cause deformation of 6. Further, since the sliding surface of the oil seal 21 is provided on the cylindrical portion 16, it is difficult for the oil seal 21 to receive heat transfer due to heat generation in the bearing of the crankshaft 12, and the heat load on the oil seal 21 can be reduced. , Oil seal 2
The heat resistant temperature condition of 1 can be reduced.

The center axes of the flywheel device 10 and the crankshaft 12 are positioned by the inner peripheral surface 16B of the cylindrical portion 16 and the outer peripheral surface 12B of the flange portion 12A. At this time, the outer peripheral surface 12 of the flange portion 12A
Since B has a configuration in which it does not slide on the oil seal 21, it is not necessary to grind the outer peripheral surface 12B of the flange portion 12A.

Lubricating oil leaking from between the inner peripheral surface 16B of the cylindrical portion 16 and the outer peripheral surface 12B of the flange portion 12 is sealed by the packing 24. According to this seal structure, since the disk-shaped packing 24 is simply interposed on the fastening surface between the mounting flange portion 13 and the flange portion 12A, there is an advantage that the assembly is easy.

FIG. 2 shows an embodiment of the invention described in claims 1, 2, and 4. In this embodiment, the following packing is applied in place of the disc-shaped packing 24 provided on the fastening surface between the mounting flange portion 13 and the flange portion 12A in the embodiment of FIG. . That is, the groove 25 is formed over the entire circumference at the corner portion on the outer circumference of the tip end of the flange portion 12A of the crankshaft 12. When the flywheel device 10 is mounted on the crankshaft 12, a ring-shaped space is formed between the inner surface of the groove 25, the inner surface of the mounting flange portion 13 and the inner peripheral surface 16B of the cylindrical portion 16.

The liquid packing 2 is placed in this space.
6 is filled. In this case, put the liquid packing 26 into the groove 2
After applying to the inner surface of 5, the flywheel device 10 is attached to the crankshaft 12. After that, the packing 26 is cured, and the packing 26 allows the inner peripheral surface 16 of the cylindrical portion 16 to be
Lubricating oil leaking from between B and the outer peripheral surface 12B of the flange portion 12A is sealed.

The seal structure of this embodiment has the advantages that it is inexpensive and that the bolts 23 are less likely to loosen as compared with the seal structure of the embodiment of FIG.

[0028]

As described above, according to the first aspect of the present invention, the mass portion, the mounting flange portion, the elastically deformable portion, and the portion which becomes the sliding surface of the oil seal are integrated. Therefore, while reducing the number of parts and the number of assembling steps, the inner peripheral surface of the boundary portion between the outer peripheral surface of the cylindrical portion and the elastically deformed portion of the plate portion and the cylindrical portion is fatigued by induction hardening treatment or chipping treatment, respectively. Since surface treatment is performed to improve strength and hardness, the fatigue strength of the R portion at the boundary between the low-rigidity elastically deformed portion and the cylindrical portion can be improved, and at the same time, the oil seal sliding surface of the outer peripheral surface of the cylindrical portion can be improved. The hardness can be improved.

Furthermore, since the sliding surface of the oil seal is provided on the cylindrical portion which is the sliding surface of the oil seal, the oil seal is less likely to receive heat transfer due to the heat generated by the bearing of the crankshaft, and thus the oil seal is not easily transferred to the oil seal. The heat load of the oil seal can be reduced, and the heat resistant temperature condition of the oil seal can be reduced.
According to the second aspect of the present invention, stress concentration is relaxed in the connection portion between the elastic deformation portion and the portion other than the elastic deformation portion of the plate portion and the connection portion between the elastic deformation portion and the cylindrical portion.

According to the invention described in claim 3, there is an advantage that the assembling is simple. According to the invention described in claim 4, there is an advantage that it is inexpensive and the fastener for fastening the flywheel device to the crankshaft is not easily loosened.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the invention described in claims 1 to 3.

FIG. 2 is a sectional view showing an embodiment of the invention described in claims 1, 2 and 4.

FIG. 3 is a sectional view of an example of a conventional flywheel device.

FIG. 4 is a sectional view of another example of a conventional flywheel device.

[Explanation of symbols]

 10 Flywheel Device 11 Mass Part 12 Crank Shaft 12A Flange Part 13 Mounting Flange Part 14 Elastic Deformation Part 15 Plate Part 16 Cylindrical Part 21 Oil Seal

Claims (4)

[Claims] 1. A mass portion located at an outer peripheral portion, a mounting flange portion located at a central portion and serving as a mounting portion to a flange portion of a crankshaft, the mass portion and the mounting flange are connected to each other, and the mounting flange is connected. A flywheel device for an internal combustion engine, comprising: a plate portion having an elastically deformable portion for allowing bending displacement between the mass portion and the mounting flange in a connecting portion with the mass portion; While integrally molding the mounting flange portion and the plate portion, a connecting portion between the mounting flange portion and the elastically deforming portion of the plate portion is a tubular portion that extends concentrically with the crankshaft shaft, and the inner peripheral surface thereof is A cylindrical portion that is fitted to the outer peripheral surface of the flange portion of the crankshaft and on which the inner peripheral surface of the oil seal fixed to the engine body is slidably mounted is integrally molded, and the outer peripheral surface of the cylindrical portion Flywheel device for internal combustion engine, characterized in that as a surface treatment for the boundary portion of the interior angle surface and the fatigue strength and hardness improvement in the elastic deformation portion and the cylindrical portion of the rate portion. 2. An inner corner surface of a portion of the plate portion other than the elastically deforming portion and a connecting portion of the elastically deforming portion on one side, and boundary portions on both sides of the connecting portion of the elastically deforming portion and the cylindrical portion. 2. The flywheel device for an internal combustion engine according to claim 1, wherein each of the inner corner surface of and the inner corner surface is formed in an R portion having a predetermined radius of curvature. 3. The flywheel device for an internal combustion engine according to claim 1, wherein a disk-shaped packing is provided on a fastening surface between the mounting flange portion and the flange portion of the crankshaft. 4. A groove is formed over the entire circumference of a corner portion of the outer periphery of the tip end of the flange portion of the crankshaft, and when the flywheel device is mounted on the crankshaft, a boundary between the inner surface of the groove and the outer peripheral surface and end surface of the flange portion is formed. The flywheel device for an internal combustion engine according to claim 1 or 2, wherein a ring-shaped space formed between the inner surface and the inner surface of the part is filled with a hardening liquid packing.