JP6984641B2 - Synchronous gear - Google Patents

Description

The present invention relates to synchronous gears.

In recent years, the use of diesel engines is increasing, and pistons are becoming larger in diameter and longer strokes. As a result, engine vibration tends to increase, so many vibration reduction technologies have been proposed. ing. Against this background, there is an increasing need for a balancer shaft composed of two eccentric shafts and synchronous gears that rotate and drive them as a mechanism for actively reducing vibration. Steel gears are often used as the synchronous gears of the balancer shaft, but there may be problems such as loud noise and difficulty in weight reduction.

Patent Document 1 describes a resin gear in which an outer peripheral portion of a gear including a tooth portion is made of a resin material and an annular or disk-shaped inner peripheral member is provided on the inner peripheral side thereof, and the outer peripheral portion of the gear including the tooth portion is provided. The portion is composed of an inner core portion made of a resin material having a high elastic coefficient and high strength and a surface layer portion made of a resin material having a low elastic coefficient covering the inner core portion, and the inner core portion is a gear inner peripheral member. On the other hand, it is rotatably fitted around the gear rotation shaft, and an engaging portion that prevents relative rotation around the gear rotation shaft is provided at the joint portion between the surface layer portion and the gear inner peripheral member. The configuration of the resin gear described above is disclosed.

Japanese Unexamined Patent Publication No. 2008-15127

However, since the synchronous gear provided on the balancer shaft rotates in synchronization with the drive gear of the crankshaft, the tooth portion of the synchronous gear that meshes at the moment when the torque that fluctuates in synchronization with the rotation of the crankshaft becomes maximum is every time. It will be the same. For this reason, it is necessary to design based on the maximum load, but if the gear does not have a damping mechanism, the problem is to increase the size of the gear, and if it has a damping mechanism, the reliability of the damping mechanism is ensured. Is an issue.

The object of the present invention has been made in view of the above-mentioned points, and the object thereof is to reduce the noise in the balancer system and to reduce the load acting on the tooth portion, which is caused by the torque fluctuation of the crankshaft. It is an object of the present invention to provide a synchronous gear which can obtain sufficient strength against a dynamic load.

The synchronous gear of the present invention that solves the above problems is provided with a disk-shaped main body portion having a center hole fitted to the balancer shaft and rotatably provided on the outer peripheral side of the main body portion so as to be integrally rotatable with the main body portion. It is a synchronous gear having a gear portion having a plurality of teeth, and the main body portion has the main body portion in the axial direction of the main body portion at a position between the center hole of the main body portion and the gear portion. At least one through hole is formed so as to penetrate the through hole, and the through hole is filled with an elastic member.

According to the present invention, it is possible to obtain a sufficient strength against a dynamic load caused by a torque fluctuation of a crank while having a low noise with respect to a gear of a single steel. Further features relating to the present invention will be apparent from the description herein and the accompanying drawings. In addition, problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

The schematic side view which shows the case where the synchronous gear which concerns on this invention is mounted on the balancer system of an internal combustion engine. The figure which shows the relationship between the torque fluctuation and the meshing position of a gear in a balancer system. FIG. 3A is a front view of the synchronous gear of the first embodiment. FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB of FIG. 3A. FIG. 4A is a front view before the elastic member of the synchronous gear of the first embodiment is provided. FIG. 4B is a cross-sectional view taken along the line IVB-IVB of FIG. 4A. FIG. 5A is a front view of the synchronous gear of the second embodiment. FIG. 5B is a cross-sectional view taken along the line VB-VB of FIG. 5A. FIG. 6A is a front view before the elastic member of the synchronous gear of the second embodiment is provided. FIG. 6B is a cross-sectional view taken along the line VIB-VIB of FIG. 6A. FIG. 7A is the front view of the synchronous gear of the third embodiment. FIG. 7B is a cross-sectional view taken along the line VIIB-VIIB of FIG. 7A. FIG. 8A is a front view before the elastic member of the synchronous gear of the third embodiment is provided. FIG. 8B is a cross-sectional view taken along the line VIIIB-VIIIB of FIG. 8A. FIG. 9A is a front view of the synchronous gear of the fourth embodiment. 9B is a cross-sectional view taken along the line IXB-IXB of FIG. 9A. FIG. 10A is a front view before the elastic member of the synchronous gear of the fourth embodiment is provided. FIG. 10B is a cross-sectional view taken along the line XB-XB of FIG. 10A. FIG. 11A is a front view of the synchronous gear of the fifth embodiment. 11B is a cross-sectional view taken along the line XIB-XIB of FIG. 11A. FIG. 12A is a front view before the elastic member of the synchronous gear of the fifth embodiment is provided. FIG. 12B is a cross-sectional view taken along the line XIIB-XIIB of FIG. 12A. FIG. 13A is a front view of the synchronous gear of the sixth embodiment. FIG. 13B is a cross-sectional view taken along the line XIIIB-XIIIB of FIG. 13A. FIG. 14A is a front view before the elastic member of the synchronous gear of the sixth embodiment is provided. 14B is a cross-sectional view taken along the line XIVB-XIVB of FIG. 14A.

FIG. 1 is a schematic diagram showing a balancer system for an automobile engine. As shown in FIG. 1, the synchronous gear 20 of the balancer system 10 according to each of the following embodiments is a balancer synchronous gear (hereinafter referred to as an engine 50) in an internal combustion engine, for example, a balancer system 10 of a 4-cycle engine 50 (hereinafter referred to as an engine 50). , Sometimes simply referred to as a synchronous gear.) Used as 20.

The engine 50 includes a piston 58 that is reciprocably inserted into the cylinder 56. The piston 58 is connected to the crankshaft 54 by a connecting rod 60. The small end 64 of the connecting rod 60 is rotatably coupled to the piston 58 by the piston pin 62, and the large end 66 of the connecting rod 60 is rotatably coupled to the crankpin 68 of the crankshaft 54. ..

A balance weight 72 is integrally provided on the crankshaft 54. The balance weight 72 is provided at a position opposite to the crankpin 68 with the rotation center of the crankshaft 54 in between, and is in the axial direction of the cylinder 56 accompanying the reciprocating motion of the piston 58, in the vertical direction in FIG. Offsets the primary vibration to. Further, the crankshaft 54 is integrally provided with a flywheel 70 and a balancer drive gear 52 so as to be rotatable.

The balancer system 10 includes a balancer shaft 12 arranged in parallel with the crankshaft 54 of the engine 50. The balancer shaft 12 has a balancer synchronous gear 20 and a balance weight 14.

In the crankshaft 54, as the balance weight 72 rotates, secondary vibration occurs in a direction intersecting the axial direction of the cylinder 56, and in FIG. 1, in the left-right direction. At this time, the rotation of the crankshaft 54 is transmitted to the balancer shaft 12 via the balancer drive gear 52 and the balancer synchronous gear 20 meshed with the balancer drive gear 52. Then, the balance weight 14 of the balancer system 10 is rotated in the opposite direction in the same phase as the balance weight 72 of the crankshaft 54, so that the secondary vibration accompanying the rotation of the balance weight 72 is canceled out and the vibration of the engine 50 is generated. It is designed to be reduced.

Since the balancer system 10 is configured to be driven by the rotation of the engine 50, when the torque transmitted from the balancer drive gear 52 to the balancer synchronous gear 20 fluctuates due to the fluctuation of the engine rotation speed due to the change of the operating condition, Vibrations and shocks are transmitted from the balancer drive gear 52 to the teeth of the balancer synchronous gear 20.

The torque received from the balancer drive gear 52 by the synchronous gear 20 of the balancer system 10 will be described. FIG. 2 is a diagram showing the relationship between the change in torque in the balancer system 10 with time and the meshing position between the balancer drive gear 52 and the balancer synchronous gear 20. In FIG. 2, schematic views A to E showing the meshing position of each balancer synchronous gear 20 and the balancer drive gear 52 are also shown in the graph showing the change over time of the torque.

As shown in FIG. 2, in the balancer system 10, since the balancer drive gear 52 and the balancer synchronous gear 20 rotate in synchronization with each other, the synchronous gears mesh with each other at the moment when the torque that fluctuates in synchronization with the rotation of the crankshaft 54 becomes maximum. The 20 teeth are the same each time (black spot teeth at points A, C, and E in FIG. 2). From this, if the operation that is overloaded with respect to the strength of the gear is continued, there is a possibility that the durability of the teeth that engage at the moment of the maximum torque described above is particularly greatly affected. Therefore, the balancer synchronous gear 20 used in the balancer system 10 of each of the following embodiments has a configuration capable of reducing the load acting on the teeth when meshing with the balancer drive gear 52.

[First Embodiment]
Hereinafter, the configuration of the synchronous gear 20 of the first embodiment will be described with reference to FIGS. 3 and 4. 3A is a front view of the synchronous gear of the first embodiment, FIG. 3B is a sectional view taken along line IIIB-IIIB of FIG. 3A, and FIG. 4A is a front view of the synchronous gear of the first embodiment before the elastic member is provided. , FIG. 4B is a cross-sectional view taken along the line IVB-IVB of FIG. 4A.

As shown in FIGS. 3 and 4, the synchronous gear 20 has a main body portion 22, a gear portion 40, and an elastic member 36. The main body portion 22 has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22 is made of a metal material such as steel or an aluminum alloy.

The main body portion 22 has at least one penetrating the main body portion 22 along the axial direction of the main body portion 22 at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. A through hole 32 is formed. In the present embodiment, a plurality of, for example, 16 circular through holes 32 are evenly arranged in the circumferential direction. The size of the through hole 32 can be set to any size. Further, a predetermined distance is provided between the through hole 32 and the through hole 32 in order to maintain the strength of the main body portion 22. For example, the size of the through hole 32 and the distance between the through hole 32 adjacent to each other and the through hole 32 are set in consideration of the stress in the torsional direction acting on the main body 22 and the strength of the main body 22. ..

The center hole 28 has a size that allows the balancer shaft 12 (see FIG. 1) to be fitted, and is a portion to which the balancer shaft 12 is fitted inside. The outer peripheral portion 30 is a portion to which the gear portion 40 is attached.

As shown in FIGS. 3A and 3B, the elastic member 36 is filled in the through holes 32 formed in the main body 22, and has a plurality of columnar shapes. The elastic member 36 is made of a resin material such as fluororubber (FKM).

The gear portion 40 is provided so as to be rotatable integrally with the main body portion 22. The gear portion 40 has an annular substrate 42 that is externally fitted to the main body portion 22, and a plurality of teeth 44 that radiate outward from the substrate 42 in the radial direction. The substrate 42 has an inner peripheral surface 46 having a predetermined width and fixed to the main body 22 facing the outer peripheral portion 30 of the main body 22. The teeth 44 and the substrate 42 have a thickness that matches the thickness of the main body portion 22.

A plurality of teeth 44 of the gear portion 40 are evenly provided in a circumferential shape, and in the first embodiment, for example, 24 teeth 44 are provided. At this time, a valley portion 45 is formed between the tooth 44 and the tooth portion 44, and the gear portion 40 is configured such that the tooth portion 44 and the valley portion 45 are alternately arranged on the substrate 42.

The gear portion 40 of the present embodiment is made of a resin material or a fiber-reinforced resin material, and for example, a fiber-reinforced resin material composed of an aramid fiber and a polyamide-amide resin is used. As for the resin material on which the gear portion 40 is formed and the material of the elastic member 36, in addition to the above materials, the resin material of the gear portion 40 is preferably harder than the material of the elastic member 36. Specifically, when the Young's modulus of the resin material of the gear portion 40 is Ep and the Young's modulus of the material of the elastic member 36 is Er, it is preferably formed of a material such that Ep> Er.

In the synchronous gear 20 of the present embodiment, since the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material and the through hole 32 is formed in the main body portion 22, the main body portion 22 has a through hole 32. The torsional rigidity is lower than that in the case where the through hole 32 is not provided. Therefore, when the power from the balancer drive gear 52 is transmitted to the synchronous gear 20, the teeth 44 of the gear portion 40 are elastically deformed, and the main body portion 22 is elastically deformed in the torsional direction. Therefore, it is possible to reduce the load acting on the teeth 44 against the dynamic load caused by the torque fluctuation of the crankshaft 54.

Further, since each through hole 32 is filled with the elastic member 36, the vibration can be attenuated in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12 via the main body portion 22, and the noise is reduced. become able to. Further, since the through holes 32 are evenly arranged in the circumferential direction, the rotational balance of the synchronous gear 20 is improved, and the effect of suppressing vibration and noise fluctuation can be obtained.

In the present embodiment, the case where the main body portion 22 is made of a metal material and the gear portion 40 is made of a resin material has been described, but the present invention is not limited to this, and both the main body portion 22 and the gear portion 40 are made of a metal material or a resin. The main body 22 may be made of a resin material, and the gear 40 may be made of a metal material.

For example, when the main body 22 and the gear 40 are integrally formed of a metal material, the strength of the synchronous gear 20 can be increased, and the through hole 32 formed in the main body 22 causes the main body 22 to twist in the twisting direction. Since it is deformed, the load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54.

Further, when the main body portion 22 and the gear portion 40 are integrally formed of a resin material, the weight can be reduced, the main body portion 22 can be manufactured at low cost, and the main body portion 22 is formed by the through hole 32 formed in the main body portion 22. Since it is deformed depending on the twisting direction, the load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54.

Further, when the main body portion 22 is made of a resin material and the gear portion 40 is made of a metal material, the strength of the teeth 44 can be increased, and the main body portion 22 is formed by the through hole 32 formed in the main body portion 22. Is deformed depending on the twisting direction, so that the load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54.

Further, the elastic member 36 provided in each through hole 32 formed in the main body portion 22 of the synchronous gear 20 of the present embodiment is not limited to the case where it is provided in all the through holes 32, and is provided at any place. You may.

[Second Embodiment]
Next, the synchronous gear 20A of the second embodiment will be described with reference to FIGS. 5 and 6. 5A is a front view of the synchronous gear 20A of the second embodiment, FIG. 5B is a sectional view taken along the line VB-VB of FIG. 5A, and FIG. 6A is a front view of the synchronous gear 20A of the second embodiment before the elastic member is provided. FIG. 6B is a front view and is a cross-sectional view taken along the line VIB-VIB of FIG. 6A.

The synchronous gear 20A has a configuration in which an annular groove portion 34 is formed in the main body portion 22A, a through hole 32A is opened in the bottom surface of the groove portion 34, and the groove portion 34 and the through hole 32A are filled with an elastic member 36A. is doing. The same reference numerals are given to the configurations common to the synchronous gear 20 of the first embodiment described above, and detailed description thereof will be omitted.

As shown in FIGS. 5 and 6, the synchronous gear 20A has a main body portion 22A, a gear portion 40, and an elastic member 36A. The main body portion 22A has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22A is made of a metal material such as steel or an aluminum alloy.

In the main body portion 22A, an annular groove portion 34 is formed on both one surface 24A and the other surface 26A at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. Has been done. These pair of annular groove portions 34 are provided at positions having the same center as the center of the main body portion 22A, and have the same size as each other. A circular through hole 32 is provided in the groove 34. The through hole 32A opens to the bottom surface of the groove portion 34, penetrates the main body portion 22A along the axial direction of the main body portion 22A, and communicates between the pair of groove portions 34.

In the present embodiment, a plurality of through holes 32A, for example, 16 through holes 32A are arranged evenly distributed over the entire circumference of the groove portion 34 in the circumferential direction. The size of the through hole 32 is shown in FIG. 5A when it is formed to have the same size as the width of the groove portion 34, but the size is not limited to this and can be formed to any size. Further, a predetermined distance is provided between the through hole 32 and the through hole 32 in order to maintain the strength of the main body portion 22.

As shown in FIGS. 5A and 5B, the elastic member 36A is filled so as to fill the groove portion 34 and the through hole 32A formed in the main body portion 22, and is integrated in the groove portion 34 and the through hole 32A. It is provided.

In the synchronous gear 20A of the present embodiment, the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material, and the groove portion 34 and the through hole 32A are formed in the main body portion 22A. The torsional rigidity of the portion 22A is lower than that in the case where the groove portion 34 and the through hole 32A are not provided. Therefore, when the power from the balancer drive gear 52 is transmitted to the synchronous gear 20A, the teeth 44 of the gear portion 40 are elastically deformed, and the main body portion 22A is elastically deformed in the torsional direction. Therefore, the load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54.

Further, since the elastic member 36A is filled in the groove portion 34 and the through hole 32A, the vibration can be attenuated in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12 via the main body portion 22A, and noise can be obtained. Can be reduced. Further, since the through holes 32A are evenly arranged in the circumferential direction, the rotational balance of the synchronous gear 20A is improved, and the effect of suppressing vibration and noise fluctuation can be obtained.

In the synchronous gear 20A of the present embodiment, as in the synchronous gear 20 of the first embodiment, the main body portion 22A and the gear portion 40 may be integrally formed of a metal material or a resin material, and the main body portion 22A may be integrally formed. May be made of a resin material, and the gear portion 40 may be made of a metal material. With such a configuration, the effect as described in the first embodiment can be obtained.

Further, in the present embodiment, the case where the annular groove portion 34 formed in the main body portion 22A is formed on both one surface 24A and the other surface 26A is shown, but the present invention is not limited to this, and one of them is not limited to this. An annular groove 34 may be formed on the surface. Then, the elastic member 36A may be provided in the groove portion 34 and the through hole 32A formed on one side thereof.

[Third Embodiment]
Next, the synchronous gear 20B of the third embodiment will be described with reference to FIGS. 7 and 8. 7A is a front view of the synchronous gear of the third embodiment, FIG. 7B is a sectional view taken along line VIIB-VIIB of FIG. 7A, and FIG. 8A is a view before the elastic member of the synchronous gear 20B of the third embodiment is provided. The front view and FIG. 8B are cross-sectional views taken along the line VIIIB-VIIIB of FIG. 8A.

The synchronous gear 20B is different in that the shape of the through hole 32A formed in the main body portion 22A of the synchronous gear 20A of the second embodiment is circular, whereas the shape of the through hole 32B is elliptical. ing. The same reference numerals are given to the configurations common to the synchronous gear 20 of the first embodiment and the synchronous gear 20A of the second embodiment described above, and detailed description thereof will be omitted.

As shown in FIGS. 7 and 8, the synchronous gear 20B has a main body portion 22B, a gear portion 40, and an elastic member 36B. The main body portion 22B has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22B is made of a metal material such as steel or an aluminum alloy.

In the main body portion 22B, an annular groove portion 34 is formed on both one surface 24B and the other surface 26B at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. Has been done. These pair of annular groove portions 34 are provided at positions having the same center as the center of the main body portion 22B, and have the same size as each other. An elliptical through hole 32B is provided in the groove 34. The elliptical through hole 32B opens at the bottom surface of the groove portion 34, penetrates the main body portion 22B along the axial direction of the main body portion 22B, and communicates between the pair of groove portions 34.

As shown in FIG. 8A, the through hole 32B is arranged so that the long axis is along the radial direction of the main body portion 22B and the short axis is along the direction orthogonal to the radial direction of the main body portion 22B. The elliptical shape of the through hole 32B is not limited to the above-mentioned shape, and may be an elliptical shape in which the major axis is inclined with respect to the radial direction of the main body portion 22B. Further, the elliptical long axis of the through hole may be provided along the circumferential direction, and the short axis may be formed along the radial direction of the main body portion 22B.

The size of the elliptical shape of the through hole 32B indicates the case where the long axis is formed to have the same size as the width of the groove portion 34, but the size is not limited to this, and any size can be formed. Further, a predetermined distance is provided between the through hole 32B and the through hole 32B adjacent to each other. In the present embodiment, the through holes 32B are formed by arranging a plurality of, for example, 16 elliptical through holes 32B evenly in the circumferential direction.

As shown in FIGS. 7A and 7B, the elastic member 36B is filled so as to fill the groove portion 34 and the through hole 32B formed in the main body portion 22B, and is integrated in the groove portion 34 and the through hole 32B. It is provided.

In the synchronous gear 20B of the present embodiment, the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material, and the groove portion 34 and the elliptical through hole 32B are formed in the main body portion 22B. Therefore, the torsional rigidity of the main body portion 22B is lower than that in the case where the groove portion 34 and the elliptical through hole 32B are not provided. Therefore, when the power from the balancer drive gear 52 is transmitted to the synchronous gear 20B, the teeth 44 of the gear portion 40 are elastically deformed, and the main body portion 22B is elastically deformed in the torsional direction. Therefore, the load acting on the teeth 44 with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54 can be further reduced.

In particular, in the present embodiment, since the through hole 32B is formed in an elliptical shape, the torsional rigidity of the main body portion 22B can be set to an appropriate value. Further, since the elastic member 36B is filled in the groove portion 34 and the through hole 32B, the vibration can be attenuated in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12, and the noise can be reduced. .. Further, by arranging the through holes 32B evenly in the circumferential direction, the balance of rotation of the synchronous gear 20B is improved, and the effect of suppressing the fluctuation of vibration and noise can be obtained.

In the synchronous gear 20B of the present embodiment, as in the second embodiment, the main body portion 22B and the gear portion 40 may be integrally formed of a metal material or a resin material, and the main body portion 22B is made of a resin material. The gear portion 40 may be made of a metal material. With such a configuration, the effects as described in the first embodiment can be obtained.

Further, in the present embodiment, the case where the annular groove portion 34 formed in the main body portion 22B is formed on both one surface 24B and the other surface 26B is shown, but the present invention is not limited to this, and one of them is not limited to this. An annular groove 34 may be formed on the surface. Then, the elastic member 36B may be provided in the groove portion 34 and the through hole 32B formed on one side thereof.

Further, the synchronous gear 20B of the present embodiment shows a case where an elliptical through hole 32B is formed in a portion where the groove portion 34 is formed, but the present invention is not limited to this, and the synchronous gear 20 of the first embodiment is not limited to this. As described above, an elliptical through hole may be formed in the main body portion 22 in which the groove portion is not formed.

[Fourth Embodiment]
Next, the synchronous gear 20C of the fourth embodiment will be described with reference to FIGS. 9 and 10. 9A is a front view of the synchronous gear 20C of the fourth embodiment, FIG. 9B is a sectional view taken along line IXB-IXB of FIG. 9A, and FIG. 10A is a front view of the synchronous gear 20C of the fourth embodiment before the elastic member is provided. 10B is a front view and is a cross-sectional view taken along the line XB-XB of FIG. 10A.

In the synchronous gear 20C, the position of the elliptical through hole 32B formed in the main body portion 22B of the synchronous gear 20B of the third embodiment is an arbitrary position, whereas the position of the through hole 32C formed in the main body portion 22C is arbitrary. Is different in that is arranged at a position corresponding to the teeth 44 of the gear portion 40. The same reference numerals are given to the configurations common to the synchronous gear 20 of the first embodiment and the synchronous gear 20C of the third embodiment, and detailed description thereof will be omitted.

As shown in FIGS. 9 and 10, the synchronous gear 20C has a main body portion 22C, a gear portion 40, and an elastic member 36C. The main body portion 22C has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22C is made of a metal material such as steel or an aluminum alloy.

In the main body portion 22C, an annular groove portion 34 is formed on both one surface 24C and the other surface 26C at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. Has been done. These pair of annular groove portions 34 are provided at positions having the same center as the center of the main body portion 22C, and have the same size as each other. An elliptical through hole 32C is provided in the groove 34. The elliptical through hole 32C opens at the bottom surface of the groove portion 34, penetrates the main body portion 22B along the axial direction of the main body portion 22C, and communicates between the pair of groove portions 34.

As shown in FIG. 9A, the through hole 32C is arranged so that the long axis is along the radial direction of the main body portion 22C and the short axis is along the direction orthogonal to the radial direction of the main body portion 22C. The elliptical shape of the through hole 32C is not limited to the above-mentioned shape, and may be an elliptical shape in which the major axis is inclined with respect to the radial direction of the main body portion 22C. Further, the elliptical long axis of the through hole may be provided along the circumferential direction, and the short axis may be formed along the radial direction of the main body portion 22C.

The size of the oval shape of the through hole 32C indicates a case where the long axis is formed to have the same size as the width of the groove portion 34, but the size is not limited to this, and any size can be formed. Further, a predetermined distance is provided between the through hole 32C and the through hole 32C adjacent to each other.

The number of through holes 32C is the same as the number of teeth 44 formed in the gear portion 40, and in the present embodiment, for example, 24 are arranged at positions corresponding to the teeth 44 of the gear portion 40, respectively. The through holes 32C are respectively arranged at positions on the inner side in the radial direction of the main body portion 22C with respect to the plurality of teeth 44 of the gear portion 40. That is, the through holes 32C and the teeth 44 are arranged side by side in the radial direction of the main body portion 22C so as to have a one-to-one correspondence with each other.

As shown in FIGS. 9A and 9B, the elastic member 36C is filled so as to fill the groove portion 34 and the through hole 32C formed in the main body portion 22C, and is integrated in the groove portion 34 and the through hole 32C. It is provided.

In the synchronous gear 20C of the present embodiment, the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material, and the groove portion 34 and the elliptical through hole 32C are formed in the main body portion 22C. Therefore, the torsional rigidity of the main body portion 22C is lower than that in the case where the groove portion 34 and the elliptical through hole 32C are not provided. Therefore, when the power from the drive gear 52 is transmitted to the synchronous gear 20C, the teeth 44 of the synchronous gear 20C are elastically deformed, and the main body portion 22C is elastically deformed depending on the twisting direction. Therefore, the load acting on the teeth 44 with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54 can be further reduced.

In particular, in the present embodiment, since the through holes 32C and the teeth 44 are arranged side by side in the radial direction of the main body portion 22C so as to have a one-to-one correspondence with each other, vibration propagates from the gear portion 40 to the balancer shaft 12. In the process, vibration can be damped and noise can be reduced.

In the synchronous gear 20C of the present embodiment, as in the third embodiment, the main body portion 22C and the gear portion 40 may be integrally formed of a metal material or a resin material, and the main body portion 22C is made of a resin material. It may be formed and the gear portion 40 may be formed of a metal material. With such a configuration, the effects as described in the third embodiment can be obtained.

In the present embodiment, the annular groove portion 34 formed in the main body portion 22C is shown in the case where it is formed on both one surface 24C and the other surface 26C, but the present invention is not limited to this, and the annular groove portion 34 is formed on either one surface. An annular groove 34 may be formed. Then, the elastic member 36C may be provided in the groove portion 34 and the through hole 32C formed on one side thereof.

The synchronous gear 20C of the present embodiment shows a case where an elliptical through hole 32C is formed in a portion where the groove portion 34 is formed, but the present invention is not limited to this, as in the synchronous gear 20 of the first embodiment. In addition, an elliptical through hole may be formed in the main body portion in which the groove portion is not formed.

[Fifth Embodiment]
Next, the synchronous gear 20D of the fifth embodiment will be described with reference to FIGS. 11 and 12. 11A is a front view of the synchronous gear 20D of the fifth embodiment, FIG. 11B is a sectional view taken along line XIB-XIB of FIG. 11A, and FIG. 12A is a front view of the synchronous gear 20D of the fifth embodiment before the elastic member is provided. 12B is a front view of FIG. 12A and is a cross-sectional view taken along the line XIIB-XIIB of FIG. 12A.

The synchronous gear 20D is different from the synchronous gear 20C of the fourth embodiment in the position where the elliptical through hole 32C formed in the main body portion 22C is formed. The same reference numerals are given to the configurations common to the synchronous gear 20 of the first embodiment and the synchronous gear 20C of the fourth embodiment, and detailed description thereof will be omitted.

As shown in FIGS. 11 and 12, the synchronous gear 20D has a main body portion 22D, a gear portion 40, and an elastic member 36D. The main body portion 22D has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22D is made of a metal material such as steel or an aluminum alloy.

In the main body portion 22D, an annular groove portion 34 is formed on both one surface 24D and the other surface 26D at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. Has been done. These pair of annular groove portions 34 are provided at positions having the same center as the center of the main body portion 22D, and have the same size as each other. An elliptical through hole 32D is provided in the groove 34. The elliptical through hole 32D opens in the bottom surface of the groove portion 34, penetrates the main body portion 22D along the axial direction of the main body portion 22D, and communicates between the pair of groove portions 34.

As shown in FIG. 11A, the through hole 32D is arranged so that the long axis is along the radial direction of the main body portion 22D and the short axis is along the direction orthogonal to the radial direction of the main body portion 22D. The elliptical shape of the through hole 32D is not limited to the above-mentioned shape, and may be an elliptical shape in which the major axis is inclined with respect to the radial direction of the main body portion 22D. Further, the elliptical long axis of the through hole may be provided along the circumferential direction, and the short axis may be formed along the radial direction of the main body portion 22D.

The size of the elliptical shape of the through hole 32D indicates the case where the long axis is formed to have the same size as the width of the groove portion 34, but the size is not limited to this, and any size can be formed. Further, a predetermined distance is provided between the through hole 32D adjacent to each other and the through hole 32D.

The number of through holes 32D is the same as the number of teeth 44 formed in the gear portion 40, and in this embodiment, for example, 24 are provided. The plurality of through holes 32D are arranged at positions corresponding to each other between the teeth 44 and the teeth 44 adjacent to each other in the gear portion 40. The through hole 32D is arranged at a position inside the main body portion 22D in the radial direction with respect to the position between the teeth 44 adjacent to each other of the gear portion 40. That is, the valley portion 45 between the teeth 44 adjacent to each other and the through hole 32D of the gear portion 40 are arranged side by side in the radial direction of the main body portion 22D so as to have a one-to-one correspondence with each other. There is.

As shown in FIGS. 11A and 11B, the elastic member 36D is filled so as to fill the groove portion 34 and the through hole 32D formed in the main body portion 22D, and is integrated in the groove portion 34 and the through hole 32D. It is provided.

In the synchronous gear 20D, the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material, and the main body portion 22D is formed with a groove portion 34 and an elliptical through hole 32D. The torsional rigidity of the 22D is lower than that in the case where the groove portion 34 and the elliptical through hole 32D are not provided. Therefore, when the power from the drive gear 52 is transmitted to the synchronous gear 20D, the teeth 44 of the synchronous gear 20D are elastically deformed, and the main body portion 22D is elastically deformed depending on the twisting direction. Therefore, the load acting on the teeth 44 with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54 can be further reduced.

In particular, in the present embodiment, in the radial direction of the main body portion 22D, the valley portion 45 between the teeth 44 adjacent to each other and the through hole 32D of the gear portion 40 have a one-to-one correspondence with each other. Since they are arranged side by side, the vibration can be attenuated and the noise can be reduced in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12.

In the synchronous gear 20D of the present embodiment, as in the fourth embodiment, the main body portion 22D and the gear portion 40 may be integrally formed of a metal material or a resin material, and the main body portion 22D is made of a resin material. It may be formed and the gear portion 40 may be formed of a metal material. With such a configuration, the effects as described in the fourth embodiment can be obtained.

In the present embodiment, the annular groove portion 34 formed in the main body portion 22D is shown in the case where it is formed on both one surface 24D and the other surface 26D, but the present invention is not limited to this, and the annular groove portion 34 is formed on either one surface. An annular groove 34 may be formed. Then, the elastic member 36D may be provided in the groove portion 34 and the through hole 32D formed on one side thereof.

The synchronous gear 20D of the present embodiment shows a case where an elliptical through hole 32D is formed in a portion where the groove portion 34 is formed, but the present invention is not limited to this, as in the synchronous gear 20 of the first embodiment. In addition, an elliptical through hole may be formed in the main body portion in which the groove portion is not formed.

[Sixth Embodiment]
Next, the synchronous gear 20E of the sixth embodiment will be described with reference to FIGS. 13 and 14. 13A is a front view of the synchronous gear 20E of the sixth embodiment, FIG. 13B is a cross-sectional view taken along the line XIIIB-XIIIB of FIG. 13A, and FIG. 14A is a front view of the synchronous gear of the sixth embodiment before the elastic member is provided. The front view and FIG. 14B are cross-sectional views taken along the line XIVB-XIVB of FIG. 14A.

In the synchronous gear 20E, through holes 32B formed in the main body portion 22B of the synchronous gear 20B of the third embodiment are provided at predetermined intervals in the circumferential direction over the entire circumference of the main body portion 22B. The difference is that the main body portion 22E is partially provided only within a predetermined angle range in the circumferential direction. The same reference numerals are given to the configurations common to the synchronous gear 20 of the first embodiment and the synchronous gear 20A of the second embodiment, and detailed description thereof will be omitted.

As shown in FIGS. 13 and 14, the synchronous gear 20E has a main body portion 22E, a gear portion 40, and an elastic member 36E. The main body portion 22E has a disk shape having a predetermined plate thickness, and a center hole 28 fitted to the balancer shaft 12 (see FIG. 1) is formed at the center thereof. The main body 22E is made of a metal material such as steel or an aluminum alloy.

In the main body portion 22E, an annular groove portion 34 is formed on both one surface 24E and the other surface 26E at a position between the center hole 28 and the gear portion 40, that is, between the center hole 28 and the outer peripheral portion 30. Has been done. These pair of annular groove portions 34 are provided at positions having the same center as the center of the main body portion 22E, and have the same size as each other. A circular through hole 32E is provided in the groove 34. The through hole 32E opens to the bottom surface of the groove portion 34, penetrates the main body portion 22E along the axial direction of the main body portion 22E, and communicates between the pair of groove portions 34.

The through hole 32E is formed only at a position corresponding to the specific tooth 44a (see the black dot portion in FIG. 2) of the gear portion 40. The specific tooth 44a is a tooth that meshes with the balancer drive gear 52 at the moment when the torque that fluctuates in synchronization with the rotation of the crankshaft 54 becomes maximum in the balancer system 10. In the present embodiment, as shown in FIG. 13A, the specific tooth 44a is a tooth that meshes with the balancer drive gear 52. Of the plurality of teeth 44, three are preset as specific teeth 44a. In the balancer system 10, the three teeth 44a of the synchronous gear 20E are assembled so as to mesh with the balancer drive gear 52 at the moment when the torque becomes maximum.

The through hole 32E is provided at a position preset in the circumferential direction of the groove portion 34, and in the present embodiment, a plurality of, for example, four circular holes are formed in the circumferential direction of the groove portion 34 within a predetermined length range. Through holes 32E are arranged and formed at equal intervals. The through hole 32E is arranged at a position corresponding to the specific tooth 44a.

As shown in FIGS. 13A and 13B, the elastic member 36E is filled so as to fill the groove portion 34 and the through hole 32E formed in the main body portion 22E, and is integrated in the groove portion 34 and the through hole 32E. It is provided.

In the synchronous gear 20E of the present embodiment, the teeth 44 of the gear portion 40 meshed with the balancer drive gear 52 are formed of a resin material, but the groove portion 34 and the circular through hole 32E are formed in the main body portion 22E. Therefore, the torsional rigidity of the main body portion 22E is lower than that in the case where the groove portion 34 and the circular through hole 32E are not provided. Therefore, when the power from the balancer drive gear 52 is transmitted to the synchronous gear 20E, the teeth 44 of the synchronous gear 20E are elastically deformed, and the main body portion 22E is elastically deformed depending on the twisting direction. Therefore, the load acting on the teeth 44 with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54 can be further reduced.

In particular, in the synchronous gear 20E of the present embodiment, the through hole 32E of the main body portion 22E is formed only in the portion corresponding to the portion where the specific tooth 44a is provided, so that the load of the tooth 44a receiving a high torque is reduced. be able to. In addition, in order to adjust the balance of the synchronous gear 20E, a through hole is formed in the same manner at a position symmetrical with respect to the portion where the through hole 32E is formed, or the main body portion 22E is shaved to reduce the weight. May be adjusted.

In the synchronous gear 20E of the present embodiment, as in the second embodiment, both the main body portion 22E and the gear portion 40 may be integrally formed of a metal material or a resin material, and the main body portion 22E is formed of a resin material. , The gear portion 40 may be made of a metal material. With such a configuration, the above-mentioned effect can be achieved.

In the synchronous gear 20E of the present embodiment, the case where the annular groove portion 34 formed in the main body portion 22E is formed on both one surface 24E and the other surface 26E is shown, but the present invention is not limited to this. An annular groove 34 may be formed on one surface. Then, the elastic member 36E may be provided in the groove portion 34 and the through hole 32E formed on one side thereof.

The synchronous gear 20E of the present embodiment shows a case where a circular through hole 32E is formed in a portion where the groove portion 34 is formed, but the present invention is not limited to this, as in the synchronous gear 20 of the first embodiment. , A circular through hole may be formed in the main body portion 22 in which the groove portion is not formed.

As described above, the synchronous gear 20 described in the present embodiment is integrated with the disk-shaped main body portion 22 having the center hole 28 fitted to the balancer shaft 12 and the main body portion 22 on the outer peripheral side of the main body portion 22. It is a synchronous gear 20 having a gear portion 40 rotatably provided and having a plurality of teeth 44, and the main body portion 22 has a main body at a position between the center hole 28 of the main body portion 22 and the gear portion 40. At least one through hole 32 that penetrates the portion 22 along the axial direction of the main body portion 22 is formed, and the through hole 32 is filled with the elastic member 36.

According to this configuration, the torsional rigidity of the main body 22 is lower than that in the case where the through hole 32 is not provided. Therefore, when the power from the drive gear 52 is transmitted to the synchronous gear 20, the teeth 44 of the synchronous gear 20 are deformed and the main body 22 is deformed in the twisting direction. Therefore, it becomes possible to reduce the load acting on the teeth 44 against the dynamic load caused by the torque fluctuation of the crankshaft 54. Since the elastic member 36 is provided in the through hole 32, the vibration can be attenuated and the noise can be reduced in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12.

In the synchronous gear 20A described in the present embodiment, the main body portion 22A is at least one of a surface 24A on one side in the axial direction of the main body portion and a surface 26A on the other side at a position between the center hole 28 and the gear portion 40. An annular groove 34 is formed on one side, a through hole 32A is formed on the bottom surface of the groove 34, and an elastic member 36A is filled in the groove 34 and the through hole 32A.

According to this configuration, since the elastic member 36A is provided in the groove portion 34 and the through hole 32, it is possible to attenuate the vibration and reduce the noise in the process of propagating the vibration from the gear portion 40 to the balancer shaft 12. Will be.

In the synchronous gear 20 described in the present embodiment, the main body portion 22 and the gear portion 40 are integrally formed of a metal material.

According to this configuration, the strength of the synchronous gear 20 can be increased, and the main body portion 22 is deformed in the twisting direction by the through hole 32 formed in the main body portion 22, so that the torque of the crankshaft 54 fluctuates. The load acting on the tooth 44 can be further reduced with respect to the resulting dynamic load.

In the synchronous gear 20 described in the present embodiment, the main body portion 22 and the gear portion 40 are integrally formed of a resin material.

According to this configuration, the weight can be reduced, the weight can be reduced, and the main body 22 can be manufactured at low cost. The through hole 32 formed in the main body 22 deforms the main body 22 in the twisting direction, so that the torque of the crankshaft 54 can be reduced. The load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the fluctuation.

In the synchronous gear 20 described in the present embodiment, the main body portion 22 is made of a metal material, and the gear portion 40 is made of a resin material.

According to this configuration, since the gear portion 40 is made of a resin material, the noise generated from the teeth 44 is reduced, and the strength of the main body portion 22 made of a metal material is increased. Then, since the main body portion 22 is deformed in the twisting direction, the load acting on the teeth 44 with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54 can be reduced.

In the synchronous gear 20 described in the present embodiment, the main body portion 22 is made of a resin material, and the gear portion 40 is made of a metal material.

According to this configuration, since the gear portion 40 is made of a metal material, the strength of the teeth 44 can be increased. Then, the main body 22 is made of a resin material and the through hole 32 is formed in the main body 22, so that the main body 22 is deformed in the twisting direction. Therefore, the load acting on the teeth 44 can be further reduced with respect to the dynamic load caused by the torque fluctuation of the crankshaft 54.

In the synchronous gear 20 described in the present embodiment, when the main body portion 22 is made of a metal material and the gear portion 40 is made of a resin material, the Young's modulus of the resin material of the gear portion 40 is the material of the elastic member 36. It is higher than the Young's modulus of.

According to this configuration, since the Young's modulus of the resin material of the gear portion 40 is higher than the Young's modulus of the material of the elastic member 36, the strength of the gear portion 40 can be increased, and the vibration caused by the elastic member 36 can be increased. It is possible to increase the attenuation and reduce the noise.

In the synchronous gear 20 described in the present embodiment, a plurality of through holes 32 are provided in the main body portion 22 and are evenly arranged in the circumferential direction of the main body portion 22.

According to this configuration, the rotational balance of the synchronous gear 20 is improved, and the structure in the circumferential direction becomes substantially symmetrical, so that it is possible to achieve the effect of suppressing vibration and noise fluctuation.

In the synchronous gear 20C described in the present embodiment, a plurality of through holes 32C are formed in the main body portion 22C, and are formed at positions on the radial inner side of the main body portion 22C with respect to the plurality of teeth 44 of the gear portion 40. ing.

According to this configuration, since the through holes 32C are provided at the positions corresponding to the teeth 44 of the gear portion 40, the structure in the circumferential direction becomes substantially symmetrical, and the effect of suppressing the fluctuation of vibration and noise can be obtained. Can be done. Further, since the elastic member 36C is filled in the through hole 32C, a more damping effect can be obtained.

In the synchronous gear 20D described in the present embodiment, a plurality of through holes 32D are formed in the main body portion 22D, and the main body portion 22D is formed with respect to the valley portion 45 between the teeth 44 adjacent to each other in the gear portion 40. It is formed at the inner position in the radial direction of.

According to this configuration, since the through hole 32D is provided at the position corresponding to each valley portion 45 of the gear portion 40, the structure in the circumferential direction becomes substantially symmetrical, so that the effect of suppressing the fluctuation of vibration and noise can be achieved. Can play. Further, since the elastic member 36D is filled in the through hole 32D, a more damping effect can be obtained.

In the synchronous gear 20E described in the present embodiment, a plurality of through holes 32E are provided in the main body portion 22E, and among the teeth 44 of the gear portion 40, the specific teeth 44a to which a higher torque is applied than the other teeth 44 are provided. It is formed at a position on the inner side in the radial direction of the main body portion 22E.

According to this configuration, the through hole 32E of the main body portion 22E is formed only in the portion corresponding to the portion where the specific teeth 44a, which increases the load when the synchronous gear 20E meshes with the drive gear 52, is provided. The load on the tooth portion that receives torque can be reduced.

In the synchronous gear 20 described in this embodiment, the through hole 32 is circular. According to this configuration, the through hole 32 can be easily formed while maintaining the strength of the main body portion 22.

In the synchronous gear 20 described in this embodiment, the through hole 32 has an elliptical shape. According to this configuration, the torsional rigidity of the main body 22 can be changed.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. You can make changes. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

12: Balancer shaft 20: Synchronous gear 22: Main body 24: One side 26: The other side 28: Center hole 32: Through hole 34: Groove 36: Elastic member 40: Gear part 44: Teeth 45: Valley part 52: Balancer drive gear 54: Crankshaft

Claims (6)

Synchronous having a disk-shaped main body having a central hole fitted to the balancer shaft, and a gear portion rotatably provided on the outer peripheral side of the main body and having a plurality of teeth. It ’s a gear,
At least one through hole is formed in the main body portion so as to penetrate the main body portion along the axial direction of the main body portion at a position between the center hole of the main body portion and the gear portion.
The through hole is filled with an elastic member .
The through hole is
A plurality of teeth having the same number of teeth as the number of teeth of the gear portion are formed on the main body portion, and are evenly arranged in the circumferential direction of the main body portion.
Each has an elliptical shape and is arranged so that the long axis is along the radial direction of the main body.
Corresponding position on the radial inner side of the main body portion with respect to the plurality of teeth, or corresponding position on the radial inner side of the main body portion with respect to the valley portion between the teeth adjacent to each other of the gear portion. Synchronous gears characterized by being placed in each. An annular groove portion is provided in the main body portion at a position between the center hole of the main body portion and the gear portion and on at least one of one side surface and the other side surface in the axial direction of the main body portion. Is formed and
The through hole is formed on the bottom surface of the groove portion, and is formed on the bottom surface of the groove portion.
The synchronous gear according to claim 1, wherein the elastic member is filled in the groove portion and the through hole. The synchronous gear according to claim 1, wherein the main body portion and the gear portion are made of a metal material and are integrally formed with each other. The synchronous gear according to claim 1, wherein the main body portion and the gear portion are made of a resin material and are integrally formed with each other. The main body is made of a metal material or a resin material, and is made of a metal material or a resin material.
The synchronous gear according to claim 1, wherein the gear portion is made of a resin material or a metal material. The synchronous gear according to claim 5, wherein when the gear portion is made of the resin material, the resin material of the gear portion has a higher Young's modulus than the material of the elastic member.

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