JP2023165228A - Gear device for internal combustion engine - Google Patents

Abstract

To provide a gear device for an internal combustion engine that can suppress vibration.SOLUTION: A gear device for an internal combustion engine includes: a first gear fitted to a crankshaft; and a second gear fitted to a balancer shaft and engaging the first gear. The first gear includes a first damper, the second gear includes a second damper, and the first damper has a resonant frequency that is different from the resonant frequency of the second damper.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gear system for an internal combustion engine.

A balancer device is sometimes provided to suppress vibrations generated in an internal combustion engine. A gear is provided on the crankshaft of the internal combustion engine, and a gear is provided on the balancer shaft of the balancer device. When these gears mesh, the balancer shaft rotates in synchronization with the crankshaft. A technique has been developed to suppress vibration by providing a rubber damper in the gear of a balancer device (for example, Patent Document 1).

JP2020-204372A

However, vibrations may not be suppressed sufficiently. Therefore, an object of the present invention is to provide a gear device for an internal combustion engine that can suppress vibration.

The above object includes a first gear attached to a crankshaft, and a second gear attached to a balancer shaft and meshing with the first gear, the first gear having a first damper, and the second gear being attached to a balancer shaft and meshing with the first gear. The second gear has a second damper, the resonant frequency of the first damper being different from the resonant frequency of the second damper, which can be achieved by a gearing of the internal combustion engine.

A gear device for an internal combustion engine that can suppress vibration can be provided.

FIG. 1 is a perspective view illustrating a gear device according to an embodiment. FIGS. 2(a) and 2(b) are front views illustrating gears.

FIG. 1 is a perspective view illustrating a gear device 100 according to an embodiment. Gear device 100 has two gears. Gear 10 (first gear) is attached to the tip of a crankshaft 30 of an internal combustion engine. A gear 20 (second gear) and a balancer mass 34 are attached to the tip of the balancer shaft 32. The crankshaft 30 and the balancer shaft 32 are spaced apart from each other and parallel to each other.

FIG. 2(a) is a front view illustrating the gear 10. FIG. The gear 10 includes a plate portion 12, a plate portion 14, and a damper 16 (first damper). The plate portion 12, the plate portion 14, and the damper 16 each have an annular shape. A plurality of teeth 12a are provided on the outer peripheral surface of the plate portion 12. The plurality of teeth 12a are arranged along the outer periphery of the plate portion 12. The plate portion 14 is located at the center of the gear 10 in the radial direction. The damper 16 is a shaded portion in FIG. 2(a). The damper 16 is provided between the plate portion 12 and the plate portion 14. That is, the damper 16 is attached to the outer peripheral surface of the plate part 14, and the plate part 12 is attached to the outer peripheral surface of the damper 16.

FIG. 2(b) is a front view illustrating the gear 20. FIG. The gear 20 has a plate portion 22, a plate portion 24, and a damper 26 (second damper). The plate portion 22, the plate portion 24, and the damper 26 each have an annular shape. A plurality of teeth 22a are provided on the outer peripheral surface of the plate portion 22. The plurality of teeth 22a are arranged along the outer circumferential direction of the plate portion 22. The plate portion 24 is located at the center of the gear 20 in the radial direction. The damper 26 is a shaded portion in FIG. 2(b). The damper 26 is provided between the plate portion 22 and the plate portion 24. That is, the damper 26 is attached to the outer peripheral surface of the plate part 24, and the plate part 22 is attached to the outer peripheral surface of the damper 26.

The plate portions 12 and 14 of the gear 10 and the plate portions 22 and 24 of the gear 20 are made of metal or resin, for example. The plate portion may be formed of a material containing iron, such as ductile cast iron (FCD). Damper 16 and damper 26 are made of rubber.

When the crankshaft 30 rotates, the gear 10 also rotates together with the crankshaft 30. The plurality of teeth 12a of the gear 10 and the plurality of teeth 22a of the gear 20 mesh with each other. Therefore, power is transmitted from gear 10 to gear 20. Gear 20 rotates in synchronization with gear 10. Balancer shaft 32 rotates together with gear 20.

The resonant frequency of damper 16 is different from the resonant frequency of damper 26. The thickness T1 of the damper 16 shown in FIG. 2(a) is smaller than the thickness T2 of the damper 26 shown in FIG. 2(b). Since the damper 16 is thinner than the damper 26, the stiffness of the damper 16 is higher than that of the damper 26. The distortion rate of the damper 16 is lower than that of the damper 26. The resonant frequency of the damper 16 is higher than the resonant frequency of the damper 26.

Vibration is suppressed by providing dampers on both gears. However, when the resonance frequencies of the two dampers are equal, the vibrations of the two dampers become large at the resonance frequency. It is difficult to suppress vibrations at the resonant frequency.

According to this embodiment, the gear 10 has the damper 16 and the gear 20 has the damper 26. The resonant frequency of damper 16 is different from the resonant frequency of damper 26. Therefore, vibration of both the damper 16 and the damper 26 at the same frequency is suppressed. As a result, vibrations can be suppressed.

By suppressing vibration, generation of noise and load on gear 10 and gear 20 can be suppressed. Vibration can be suppressed by making the resonance frequencies different between the two dampers. There is no need to increase the size of the damper to suppress vibration.

Damper 26 is thicker than damper 16. The stiffness of the damper 16 becomes higher than the stiffness of the damper 26, and the resonance frequency of the damper 16 becomes higher than the resonance frequency of the damper 26. The thickness T2 of the damper 26 may be, for example, 1.2 times or more, 1.5 times or more, or 2 times or more the thickness T1 of the damper 16.

In order to make the resonance frequencies different, the thickness T1 of the damper 16 only needs to be different from the thickness T2 of the damper 26. For example, damper 16 may be thicker than damper 26. However, by making the damper 16 thicker, the stiffness of the damper 16 becomes lower than the stiffness of the damper 26, and the strain rate of the damper 16 becomes higher than that of the damper 26. A load is applied to the damper 16 from the balancer mass 34 and the like. If a load is applied to the damper 16, which has low rigidity, there is a risk that the damper 16 will be damaged. The damper 16 is made thinner than the damper 26 in order to have different resonance frequencies and to increase the rigidity of the damper 16. The rigidity of the damper 16 can be increased and damage can be suppressed.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

10, 20 Gear 12, 14, 22, 24 Plate portion 12a, 22a Teeth 16, 26 Damper 30 Crankshaft 32 Balancer shaft 34 Balancer mass 100 Gear device

Claims (1)

a first gear attached to the crankshaft;
a second gear attached to the balancer shaft and meshing with the first gear;
the first gear has a first damper;
the second gear has a second damper;
A gearing device for an internal combustion engine, wherein a resonant frequency of the first damper is different from a resonant frequency of the second damper.

Images