JPH0121240Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to improvement of an idler gear device.

As a conventional idler gear device, Utility Model 52-125672
No. 7-17872 and No. 55-52090 are disclosed.

Among these free rotating gear devices, for example, the one shown in FIG.
To explain the conventional device shown in FIG. 2, the main gear 1 has a needle bearing 3 around the shaft 2.
The gear 4 is installed so that it can rotate freely.

Lubricating oil is supplied from the outer side of the gear 4 to the inner needle bearing 3 through the oil hole 5 that communicates between the tooth bottom surface 6 and the inner circumferential surface 7 of the gear 4.

The oil holes 5 are formed at four selected locations on the tooth bottom surface 6 along approximately the center of the tooth width so that oil is evenly supplied to the entire bearing 3 from all sides.

The lubricating oil adhering to the tooth surface of the gear 4 is guided from the tooth root surface 9 through the oil hole 5 to the inner bearing 3 by the extrusion pressure or meshing pressure of the tip of the other tooth when it meshes with the gear 8. It's becoming like that.

However, in such a conventional free-rotating gear device, since the oil hole 5 is open to the tooth root surface 6, stress is generated in the rising boundary area from the tooth root surface 6 to the tooth root surface 9 around the oil hole 5. Concentration occurred, causing a decrease in the bending strength of the gear 4.

The present invention aims to solve these conventional problems.

To this end, the present invention provides an idling gear device in which lubricating oil is pumped from the teeth of the gear to the inside of the gear based on the meshing pressure when the gear meshes with a mating gear to lubricate the bearing inside the gear. An oil hole penetrating from the tooth tip surface to the inner peripheral surface is provided approximately at the center of the tooth width and approximately perpendicular to the tooth tip surface.

This eliminates the opening of the oil hole to the root of the tooth, which avoids stress concentration on the root of the tooth, which is disadvantageous in terms of strength.Moreover, the oil hole is located approximately at the center of the tooth width, approximately perpendicular to the tooth tip surface. Since the gear is open, the lubricating oil does not escape to both end faces when the gear rotates, and the lubricating oil is efficiently supplied to the internal bearing portion.

Embodiments of the present invention will be described below with reference to the drawings, in which the same components as in FIGS. 1 and 2 are designated by the same reference numerals.

As shown in FIGS. 3 and 4, a needle bearing 3 is interposed on the inner circumferential side of the gear 4 and located on the outer circumference of the shaft 2. As shown in FIGS.

The inner peripheral surface 7 of the gear 4 facing the needle bearing 3 has an oil hole 11 communicating with the tooth tip surface 10.
are formed around the gear 4 at approximately equal intervals.

Further, the oil hole 11 is formed to penetrate through the gear 4 so as to open approximately at the center of the tooth width and to be approximately perpendicular to the tooth tip surface.

According to the above configuration, the lubricating oil supplied to the bearing 3 is provided so that the tooth bottom surface 12 of the opposing gear 8 is connected to the oil hole 1.
1, it is pushed out from the oil hole 11 to the bearing 3 on the inner peripheral side by the meshing pressure of the gears 4 and 8.

Thereby, the lubricating oil adhering to the tooth surface of the gear 4 can be actively supplied to the inner bearing 3, and the lubrication performance of the gear 4 is improved. In particular, since the oil hole 11 opens approximately at the center in the tooth width direction and approximately perpendicularly to the tooth tip surface 10, lubricating oil is prevented from escaping to both end surfaces of the gear 4 when the gear rotates. The meshing pressure acts effectively and lubricating oil is efficiently supplied to the three internal bearing parts.

Furthermore, even if bending is applied to the tooth root surface 9 when the gears 4 and 8 are engaged, the oil hole 11 is opened not in the tooth root surface 6 but in the tooth tip surface 10, so that the tooth root surface 6 and the tooth root surface 9 can be bent. No stress concentration occurs in the boundary region (rising portion) between the gear 4 and the gear 4, and therefore the bending strength of the gear 4 does not decrease.

FIG. 5 shows another embodiment, in which the gear 4
A flat part 12 parallel to the tooth tip surface 10 and recessed in a concave shape is provided in the tooth tip surface 10, and an oil hole 11 is provided in this flat part 12.
It is opened.

This embodiment has the unique effect of not only increasing the bending rigidity of the gear 4 but also improving the workability in cutting the oil hole 11.

As described above, according to the present invention, the oil hole penetrating from the tooth tip surface to the inner peripheral surface of the gear is provided approximately at the center of the tooth width and approximately perpendicular to the tooth tip surface, thereby reducing stress concentration. It is possible to avoid a decrease in the bending strength of the root portion of the gear, which is likely to occur, and to efficiently supply lubricating oil from the meshing surface of the gear to the bearing section inside the gear, thereby ensuring good lubrication performance.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the conventional example, and Figure 2 is A of Figure 1.
3 is a sectional view of an embodiment of the present invention, FIG. 4 is a perspective view taken in the direction of arrow B in FIG. 3, and FIG. 5 is a perspective view of another embodiment. 2...Shaft, 3...Needle bearing,
4...Gear, 5...Oil hole, 6...Tooth bottom surface, 7...
Inner peripheral surface, 10...Tooth tip surface.

Claims (1)

[Scope of utility model registration request] In an idling gear device that lubricates the bearing inside the gear by pumping lubricating oil from the teeth of the gear to the inside of the gear based on the meshing pressure when it meshes with a mating gear, An idling gear device characterized in that an oil hole penetrating the surface is provided approximately in the center of the tooth width and approximately perpendicular to the tooth tip surface.