Shaft damper of transmission

A shaft damper of a transmission is provided to improve an NVH characteristic such as rattle noise of a transmission by effectively reducing target resonance as a problem in whole rpm ranges by adding a structure to minimize one resonance and additionally reduce the resonance with respect the other resonance between two resonances while converting the target resonance as the problem into two divided resonances by mounting a structure which applies inertia to an input shaft or an output shaft, a counter shaft, or a PTO shaft of the transmission.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2011-0117520 filed Nov. 11, 2011, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a damper installed on a shaft of a transmission, and more particularly, to a technology that reduces rattle noise of the transmission by avoiding resonance in a specific rpm range by applying additional inertia to an input shaft of the transmission.

2. Background Art

As disclosed in citation lists below, an input shaft damper configured to include an inertia plate is provided on an input shaft of a transmission to effectively avoid resonance in a specific rpm range in which rattle noise of the transmission is problematic without using a dual mass flywheel (DMF).

However, accurate tuning is required to appropriately reduce the resonance in the specific rpm range with the ISD. That is, as illustrated inFIG. 1, when the ISD which is not accurately tuned is applied to the input shaft of the transmission in order to reduce resonance around 1600 RPM, an original first resonance point a is divided into both sides to form a first resonance point a-1and a second resonance point a-2and an amplitude of the second resonance point a-2as one of two divided resonance points decreases to achieve an ISD mounting effect, but the first resonance point a-1, as the other one may be still amplified to a larger amplitude than the first resonance point a as illustrated inFIG. 1.

Accordingly, an appropriate tuning countermeasure should be taken in order to increase inertia by mounting a structure (hereinafter, referred to as shaft damper) such as the ISD on the input shaft or an output shaft, a counter shaft, or a power take off (PTO) shaft of the transmission.

SUMMARY OF INVENTION

Various aspects of the present invention provide for a shaft damper of a transmission that can improve an NVH characteristic such as rattle noise of a transmission by effectively reducing target resonance as a problem in whole rpm ranges by adding a structure to minimize one resonance and additionally reduce the resonance with respect the other resonance between two resonances while converting the target resonance as the problem into two divided resonances by mounting a structure which applies inertia to an input shaft or an output shaft, a counter shaft, or a PTO shaft of the transmission.

Various aspects of the present invention provide for a shaft damper of a transmission, including: a shaft rotatably installed in the transmission; a drive plate installed on the shaft with rotation constrained; a first inertia plate installed to be relatively rotatable to the shaft; a first electric member installed to provide elastic force while being elastically transformed by relative rotation between the drive plate and the first inertia plate; a second inertia plate installed to be relatively rotatable to the first inertia plate with the shaft as a rotary shaft; and a second elastic member installed to provide elastic force while being elastically transformed by relative rotation between the first inertia plate and the second inertia plate.

Various aspects of the present invention provide for a shaft damper of a transmission, including: a shaft rotatably installed in the transmission; a first inertia body mounted on the shaft while being elastically relatively rotatable within a specific range with respect to the shaft; and a second inertia body installed to be elastically relatively rotatable with a specific range with respect to the first inertia body with the shaft as a rotary shaft.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention.

DETAILED DESCRIPTION

Referring toFIGS. 2 and 3, a shaft damper of a transmission according to various embodiments of the present invention includes a shaft1rotatably installed in the transmission, a drive plate3installed on the shaft1with rotation constrained, a first inertia plate5installed on the shaft1to be relatively rotatable, a first elastic member7installed to provide elastic force while being elastically transformed by relative rotation between the drive plate3and the first inertia plate5, a second inertia plate9installed to be relatively rotatable with respect to the first inertia plate5with the shaft1as a rotational shaft, and a second elastic member11installed to provide elastic force while being elastically transformed by relative rotation between the first inertia plate5and the second inertia plate9.

That is, the present invention is a structure which includes the first inertia plate5as a first inertia body mounted on the shaft1to be elastically relatively rotatable within a specific range with respect to the shaft1rotatably installed in the transmission and includes the second inertia plate9as a second inertia body installed to be elastically relatively rotatable within a specific range with respect to the first inertia body with the shaft1as the rotational shaft, wherein the first inertia plate5and the second inertia plate9are, elastically in series, connected to the shaft1in sequence.

The second inertia plate9has relatively smaller rotary inertia than the first inertia plate5and the second inertia plate9is installed even on the shaft1as well as the first inertia plate5to be relatively rotatable.

A stopper pin13is installed between the drive plate3and the first inertia plate3to restrain a relative rotating amount therebetween and the stopper pin13is installed even between the first inertia plate5and the second inertia plate9to restrain the relative rotating amount therebeween.

Since a mechanism may be implemented by a mechanism which is the same as or similar as an ISD device in the related art to restrain the relative rotating amounts between the drive plate3and the first inertia plate5or the first inertia plate5and the second inertia plate9by installing the stopper pin13, a detailed description of the mechanism will be omitted.

The illustrated shaft dampers ofFIGS. 2 and 3are the similar as each other in that the first inertia plate5is installed while enclosing the drive plate3and a driving unit5-1for transferring rotary force to and from the second inertia plate9is integrally formed in the first inertia plate5. One will appreciate that in various embodiments, the first and second inertial plates may be monolithically formed.

However, in the embodiment illustrated inFIG. 2, the driving unit501extends from the first inertia plate5and thereafter, extends outward from a radial-direction inner part of the second inertia plate9and the second inertia plate9is installed to enclose a radial-direction outer part of the driving unit5-1.

Herein, the first inertia plate5and the driving unit5-1are installed to be relatively rotatable to the shaft1through a first bearing15and the second inertia plate9is installed to be relatively rotatable to the driving unit5-1through a second bearing17.

This structure is more advantageous than the illustrated embodiment ofFIG. 3in terms of ensuring the inertia of the second inertia plate9, and as a result, it is advantageous to increase inertia by a method for easily increasing a diameter of the second inertia plate positioned outside the drive plate3.

Meanwhile, in the illustrated shaft damper ofFIG. 3, the driving unit5-1extends from the first inertia plate5and thereafter, extends inward from a radial-direction outer part of the second inertia plate9and the second inertia plate9is installed to enclose a part extending in the radial-direction inner part of the driving unit5-1.

Herein, the first inertia plate5is installed to be relatively rotatable to the shaft1through the first bearing15and the second inertia plate9is installed to be relatively rotatable to the driving unit5-1through the second bearing17and installed to be relatively rotatable to the shaft1through the first bearing15.

In this structure, it is more difficult to ensure inertia through increasing the size of the second inertia plate9by using the driving unit5-1than the illustrated shaft damper ofFIG. 2, but a shaft-direction width may be relatively small, and as a result, it is more advantageous in mountability.

The shaft damper of the transmission according to the various embodiments of the present invention configured as above may be applied to the input shaft of the transmission and besides, may be installed in various other shafts installed in the transmission, and as a result, for example, the shaft damper is installed even on an output shaft, a counter shaft, or a PTO shaft to show an effect thereof.

FIG. 4is a graph illustrating the effect which the shaft damper of the transmission according to various embodiments of the present invention shows and illustrates that an initial resonance point A while the shaft damper is not mounted is divided into two resonance points of which amplitudes decrease as the shaft damper is mounted, such as a first resonance point A-1and a second resonance point A-2.

The first inertia plate5is divided into both resonance points to alleviate one resonance point A-2of two points to an amplitude smaller than the initial resonance point A, but decrease the amplitude thereof even with respect to the other resonance point A-1which is alleviated more slightly than the initial resonance point A or transformed to the amplitude of the same level or higher by additionally mounting the second inertia plate9when alleviation of the other resonance point A-1is slighter than the initial resonance point A or the other resonance point A-1is transformed to a state having the same level or the larger amplitude.

Accordingly, the shaft damper of the transmission according to various embodiments of the present invention can significantly improve NVH characteristics of the transmission and a power train including the transmission by actively reducing or alleviating a resonance phenomenon to the minimum which may occur in the transmission.

According to various embodiments of the present invention, an NVH characteristic such as rattle noise of a transmission can be improved by effectively reducing target resonance as a problem in whole rpm ranges by adding a structure to minimize one resonance and additionally reduce the resonance with respect the other resonance between two resonances while converting the target resonance as the problem into two divided resonances by mounting a structure which applies inertia to an input shaft or an output shaft, a counter shaft, or a PTO shaft of the transmission.

For convenience in explanation and accurate definition in the appended claims, the terms upper or lower, front or rear, inside or outside, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.