JP2599559Y2 - Shaft structure of gear transmission shaft with synchro mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft structure of a gear transmission shaft with a synchronization mechanism.

[0002]

2. Description of the Related Art Referring to FIG. 2, the structure of a conventional gear transmission shaft with a synchronization mechanism will be described.
Is rotatably supported via a bearing 3, and a synchronizing hub 4 is axially opposed to the gear 2 on the transmission shaft 1.
Are attached by a spline fitting portion 5. That is,
For the spline teeth formed on the outer circumference of the transmission shaft 1,
Press the spline teeth formed on the inner circumference of the
The bush 4 is fitted over the transmission shaft 1. The transmission shaft 1 is hollow and has a lubrication hole 6 formed therein. Since a synchronizing mechanism using the synchronizing hub 4 is well known, a detailed description thereof will be omitted.

[0003] In such a shaft structure, the gear 2 meshes with another gear (not shown) to transmit the rotation. However, the meshing of these gears causes vibrations. This is the force generated at the point of engagement. Factors that determine the magnitude of this force, that is, the sound vibration performance, include a balance between the bending stiffness and the torsional stiffness of the transmission shaft 1 that supports the gear 2, and it is preferable that the bending stiffness be high and the torsional stiffness be low. (If the bending stiffness is reduced, the direction of the meshing action line of the gear 2 and the other gear meshing with the gear 2 is shifted due to the bending of the transmission shaft 1, and rotation unevenness occurs to deteriorate sound vibration performance.)

[0004]

However, in the conventional shaft structure, the transmission shaft 1 has almost the same cross-sectional shape over its entire length, and both of the above requirements of bending rigidity and torsional rigidity are satisfied. It was practically impossible to satisfy both.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a synchro hub in which a synchro hub is axially opposed to a gear on a transmission shaft for supporting the gear. In the gear transmission shaft with a mechanism, the synchro hub is fitted to the transmission shaft with appropriate play in the rotational direction, and a cross-sectional area of a part of the transmission shaft at the fitting portion is smaller than other parts. It is characterized by having been set.

[0006]

According to the present invention, the synchro hub is fitted to the transmission shaft with a play in the rotation direction as appropriate, and a part of the transmission shaft at this fitting portion is set to have a smaller cross-sectional area than other portions. The torsional stiffness can be reduced compared to the case where the transmission shaft is formed with the same cross section over the entire length, and the synchro hub straddles this small cross-sectional area with respect to the bending stiffness. And the same bending rigidity can be maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a gear transmission shaft with a synchronizing mechanism according to an embodiment of the present invention will be described with reference to FIG. The basic structure of this embodiment is the same as that of the conventional example shown in FIG. 2, and the same members are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the transmission shaft 1 is formed on the outer periphery.
Formed on the inner periphery of the synchro hub 4 for the spline teeth
The spline fitting portion 5A of the synchro hub 4 into which the ply teeth are press-fitted to the transmission shaft 1 is in a fitting state (large-diameter press-fitting) having an appropriate play in the rotation direction. Further, an annular groove 7 is formed on a part of the outer peripheral surface of the transmission shaft 1 facing the fitting portion 5A, and the outer periphery of this part is smaller in diameter and cross-sectional area than other parts by the annular groove 7. Small diameter part 1A
It has become. The diameter of such a small diameter portion 1A is reduced within a range of strength of the transmission shaft 1 within an allowable range.

In this embodiment, the spline fitting portion 5A is
The transmission shaft 1 is the same because it is in a fitted state (large-diameter press-fitting) having play in the rotation direction and the transmission shaft 1 facing the fitting portion 5A is provided with the small-diameter portion 1A. The torsional rigidity can be reduced as compared with the conventional example of the cross section.
Further, since the synchro hub 4 is in a state of straddling the small diameter portion 1A, it is possible to suppress a decrease in the bending rigidity of the transmission shaft 1.

That is, in this embodiment, since only the torsional rigidity can be reduced without lowering the bending rigidity of the transmission shaft, the sound vibration performance can be improved.

[0011]

According to the present invention, the torsional stiffness of the transmission shaft can be reduced and the bending stiffness can be suppressed from being reduced, so that the sound and vibration performance can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gear transmission shaft with a synchronization mechanism according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional gear transmission shaft with a synchronization mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission shaft 1A Small diameter part 2 Gear 4 Synchro hub 5A Spline fitting part 7 Annular groove

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 55/14 F16H 55/17 F16H 3/12 F16D 23/06

Claims (1)

(57) [Scope of request for utility model registration] 1. A gear transmission shaft with a synchronizing mechanism, wherein a synchro hub is disposed on a transmission shaft for supporting a gear in the axial direction so as to face the gear in an axial direction. A shaft structure of a gear transmission shaft with a synchronizing mechanism, wherein the gear transmission shaft with a synchronization mechanism is fitted in a state in which the transmission shaft has, and a cross-sectional area of a part of the transmission shaft at the fitting part is set smaller than other parts.