JPH10122337A - Molded gear and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation and damage of a side wall even in the case of large torque being repeatedly applied to the tooth surface by arranging ribs radially along lines connecting both ends of the ribs to tooth roots of a tooth profile and the axis of a hub, integrally with the side wall. SOLUTION: Ribs 6 (6a-6f) are provided integrally with a side wall 5 and radially arranged along lines connecting tooth roots 2a of a tooth profile 2 to the axis of the hub 4, and both ends of the ribs 6 are respectrively connected to a rim 3 and a hub 4. In case force acts tangentially upon the tooth surface of a molded gear 1 and this force acts upon the tooth surface of the tooth profile positioned near a part provided with the rib 6, this force is transmitted to the rib 6, but since the width of the rib 6 is the same as the width of the tooth surface, and the side wall 5 provided at the center part of the ribs 6 also has the same thickness as the width of the tooth surface, the side wall 5 is not deformed. In case force acts upon the tooth surface of the tooth profile positioned at an intermediate part between the ribs 6, since the adjacent ribs 6, the rim 3, the hub 4 and the side wall 5 form grated shape that is not easily deformed. Deformation and damage are not therefore generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded gear used for a rotary drive system and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there is a molded gear in which a rim having a tooth profile on an outer periphery and a hub coaxial with the rim are connected by a side wall having a uniform thickness.

In general, when a molded product has a large thickness, dents (sinks) occur on the surface during cooling. Therefore, a molded gear is designed to have a uniform thickness. The thickness of the connecting side wall is less than the width of the rim.

[0004]

In the conventional molded gear, the thickness of the side wall connecting between the rim and the hub is:
Because the width is smaller than the rim width, when a large torque is applied to the molded gear, the force applied to the tooth surface is applied to the tooth surface width, that is, the side wall that is smaller than the rim width, and the side wall is deformed, and the deformation is repeated. There was a problem that it would eventually break.

An object of the present invention is to provide a molded gear whose side walls are not deformed even when a large torque is repeatedly applied to the tooth surface, and a method of manufacturing the same.

[0006]

In order to achieve the above object, in a molded gear and a method of manufacturing the same according to the present invention, both ends are respectively connected to a rim and a hub, and a tooth valley of the tooth profile and an axis of the hub are aligned. Ribs radially arranged along the connecting line are provided integrally with the side wall.

[0007]

Embodiments of the present invention will be described with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals. 1 is a front view showing a formed gear according to an embodiment, FIG. 2 is a sectional view taken along line AA of the formed gear shown in FIG. 1, and FIG. 3 is a sectional view taken along line BB of the formed gear shown in FIG. FIG. A molded gear 1 includes a rim 3 having a tooth profile 2 on its outer periphery,
A hub 4 coaxial with the rim 3, a side wall 5 having a uniform thickness connecting the rim 3 and the hub 4, and a plurality of ribs 6 (hereinafter, generally referred to as ribs 6); It is molded integrally with the material.

The ribs 6 are connected at both ends to the rim 3 and the hub 4, are radially arranged along a line connecting the tooth valley 2 a of the tooth profile 2 and the axis of the hub 4, and are provided integrally with the side wall 5. ing. Since one end of the rib 6 is connected to the rim 3 located at the tooth valley 2a of the tooth profile 2, even if a depression (sink) occurs on the surface of the tooth valley 2a, the rib 6 is at a position irrespective of the gear meshing.

In the embodiment of the present invention, the width of the rim 3 and the width of the rib 6 are the same. The number of teeth is 40 and the number of ribs 6 is 6. That is, in each rib 6, the ribs 6b, 6c, 6e, 6f are arranged at a position at a central angle of 54 ° from a cutting line BB passing through the centers of the ribs 6a, 6d symmetrical with respect to the axis.

Next, the operation will be described. When the hub 4 is fixed to a shaft (not shown) connected to a load, and a large torque is applied to the formed gear 1 from a gear (not shown), a force acts on the tooth surface in a tangential direction.

When a force acts on the tooth surface of the tooth profile located near the position where the rib 6 is provided, the force is applied to the rib 6, but the width of the rib 6 is the same as the width of the tooth surface. Since the side wall 5 is provided at the center, the side wall 5 has the same thickness as the width of the tooth surface, and the side wall is not deformed.

When the force F acts on the tooth surface of the tooth profile located in the middle of the position where the rib 6 is provided, the adjacent rib 6, the rim 3, the hub 4 and the side wall 5 are hardly deformed. Therefore, the side wall 5 has the same thickness as the width of the tooth surface, and does not deform or break.

In this embodiment, in a molded gear in which a rim having a tooth profile on the outer periphery and a hub coaxial with the rim are connected by side walls having a uniform thickness, both ends are connected to the rim and the hub, respectively. The ribs radially arranged along the line connecting the tooth valley of the tooth profile and the axis of the hub are provided integrally with the side wall,
By similarly providing a molded gear connected with a plurality of ribs between a rim having a tooth profile on the outer periphery and a hub coaxial with the rim, a depression (sink) is generated on the surface of the tooth valley. However, since the position is not related to the meshing of the gears, a molded gear with high meshing accuracy can be obtained.

Further, in the present embodiment, the center angles of the ribs arranged radially with respect to the axis are made non-uniform, but making them equal makes it more effective.

[0015]

Since the present invention is configured as described above, it has the following effects. Both ends are connected to the rim and hub along the line connecting the tooth-shaped tooth valley and the hub axis, respectively.By arranging the ribs provided integrally on the side wall radially, large torque is repeatedly applied to the tooth surface. It does not deform when added.

Further, when forming the gear, one end of the rib is connected to the rim located at the tooth valley of the tooth profile, so that even if a recess (sink) occurs on the surface of the tooth valley, the gear meshes. , It is possible to obtain a formed gear with high meshing accuracy.

[Brief description of the drawings]

FIG. 1 is a front view showing a formed gear according to an embodiment.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along a line BB in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Formed gear 3 Rim 4 Hub 5 Side wall 6 Rib

Claims (3)

[Claims] 1. A molded gear in which a rim provided with a tooth profile on the outer periphery and a hub coaxial with the rim are connected by a side wall having a uniform thickness, wherein both ends are connected to the rim and the hub, respectively. A molded gear, characterized in that ribs radially arranged along a line connecting the tooth valley of the tooth profile and the axis of the hub are provided integrally with the side wall. 2. A molded gear in which a rim provided with a tooth profile on the outer periphery and a hub coaxial with the rim are connected by a plurality of ribs, wherein the rib defines a tooth valley of the tooth profile and an axis of the hub. A molded gear characterized by being radially arranged along a connecting line. 3. A method for manufacturing a formed gear in which a rim having a tooth profile provided on an outer periphery thereof and a hub coaxial with the rim are connected by a plurality of ribs, wherein the rib comprises a tooth valley of the tooth profile and a hub. Characterized by radially arranged along a line connecting the shaft center of (i) and (ii) so as to prevent a depression (sink) from being generated in the tooth ridge of the tooth profile.