JPH01164862A - Gear fixing structure - Google Patents

Abstract

PURPOSE:To eliminate the necessity of use of a come-off checker by forming, in the forward end part of a roller shaft, a flat surface part parallel to the axis of the shaft and a groove along the periphery of the forward end part, and by forming, in a gear, a hole having a cross-sectional shape corresponding to the cross-sectioned shape of the forward end part of the roller shaft and an inner diameter which is smaller at one end than that of the cross-sectioned shape. CONSTITUTION:A flat surface part 1a and a groove 1b are formed in the forward end part of a roller shaft 1, and a gear 4 is, for example, formed of a lightweight material such as synthetic resin or the like, and is formed at its center with a center hole 4b into which the forward end part of the roller shaft 1 is fitted. The diameter of a gear inner diameter end part 4a at the forward end of the center hole 4b is set to be smaller than that of the other part of the center hole 4b. Upon assembly, the gear 4 is press-fitted onto the forward end part of the roller shaft 1 through the center hole 4b. Accordingly, the gear inner diameter end part 4a is resiliently expanded, and then it reaches the groove 1b in the roller shaft 1, the gear inner diameter part 4b is engaged in the groove 1b. The engagement of the gear inner diameter end part 4a into the groove 1b serves to clamp the forward end part of the roller shaft 1, the gear 4 is secured to the forward end part of the roller shaft 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear fixing structure, and more particularly to a gear fixing structure for fixing a roller shaft drive gear for relatively light loads such as facsimile machines and copying machines.

[Prior Art] Conventionally, this type of gear fixing structure has a gear fixing structure in which a flat part parallel to the axis is formed at one end of the roller shaft, and a gear having a center hole having the same cross-sectional shape as the one end of the roller shaft is attached to the roller. The gear was inserted into one end of the shaft, and a fastener such as an E ring or C ring was used to prevent the gear from coming off in the axial direction, thereby fixing the gear to the roller shaft.

[Problems to be Solved by the Invention] The conventional gear fixing structure described above has a flat part provided at one end of the roller shaft, a gear having a center hole with the same cross-sectional shape inserted into this one end, and an E ring, a C Since the structure is such that a fastener such as a ring is used to prevent the gear from coming off in the axial direction, it has the disadvantage of being complicated and difficult to stop. Furthermore, since an E-ring or the like is used, the assembly cost is high.

[Means for Solving the Problems] The present invention has been made in order to solve the above-mentioned problems of the conventional art. The gear is provided with a flat part and a groove along the circumference of the tip thereof, and the gear is formed with a center hole that corresponds to the cross-sectional shape of the tip of the roller shaft and whose inner diameter at one end is smaller than the cross-sectional shape. , provides a gear fixing structure characterized in that the gear is press-fitted and fixed to the tip end of the roller shaft through the center hole.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a gear fixing structure according to an embodiment of the present invention, and FIG. 2 is a plan view showing the gear shown in FIG. 1.

The gear fixing structure is formed by press-fitting the gear 4 onto the tip of the roller shaft 1.

The roller shaft 1 is rotatably incorporated into the side plate 2 via a bearing 3. The tip of the roller shaft 1 has a flat part 1a and a groove 1.
b is formed. The flat portion 1a is formed by notching the distal end of the roller shaft 1 parallel to the axis to the distal end, and as a result, the cross section of the distal end of the roller shaft 1 has a partially cut-out circular shape. The groove 1b is formed by cutting the tip of the roller shaft 1 along the circumference to a predetermined depth.

The gear 4 is made of a lightweight material such as synthetic resin, and has a center hole 4b into which the tip of the roller shaft 1 is inserted. The cross-sectional shape of the center hole 4b is formed to correspond to the cross-sectional shape of the tip of the roller shaft 1, thereby allowing the gear 4 inserted into the tip of the roller shaft 1 to rotate. Further, the diameter of the gear inner diameter end 4a at the tip of the center hole 4b is set smaller than the other diameters of the center hole 4b. That is, the size is set such that the gear inner diameter end 4a can fit into the groove 1b. As a result, the inner diameter end portion 4a of the gear is connected to the roller shaft 1.
The gear 4 is engaged with the groove 1b to prevent the gear 4 from coming off the roller shaft 1.

Next, a method of fixing the gear 4 to the roller shaft 1 will be explained.

The gear 4 is inserted into the tip of the roller shaft 1 through the center hole 4b. At this time, since the center hole 4b of the gear 4 is smaller than the tip of the roller shaft 1, the gear 4 is press-fitted.

When the gear 4 is press-fitted, the inner diameter end 4a of the gear expands due to elasticity, and when it reaches the groove 1b of the roller shaft 1, the inner diameter end 4a of the gear engages with the groove 1b. Since the engagement of the inner diameter end portion 4a of the gear with the groove 1b acts to sandwich the tip portion of the roller shaft 1, the gear 4 is fixed to the tip portion of the roller shaft 1.

[Effects of the Invention] As explained above, the gear fixing structure of the present invention provides the tip of the roller shaft of a facsimile machine, copying machine, etc. with a flat portion parallel to the shaft and a groove along the circumference of the tip. A center hole is formed that corresponds to the cross-sectional shape of the tip of the roller shaft and one end of which has an inner diameter smaller than the cross-sectional shape, and the gear is press-fitted and fixed to the tip of the roller shaft through the center hole. Because of this structure, the gear can be easily assembled by pushing the gear from the outside of the roller shaft without using fasteners such as E-rings and C-rings as in the conventional case. As a result, applications such as automatic assembly can be easily realized, and even complex devices can be assembled at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a gear fixing structure according to an embodiment of the present invention, and FIG. 2 is a plan view showing the gear shown in FIG. 1.

Claims (1)

[Claims] The tip of the roller shaft of a facsimile machine, copying machine, etc. is provided with a flat part parallel to the axis and a groove along the circumference of the tip, and the gear has one end of the inner diameter that corresponds to the cross-sectional shape of the tip of the roller shaft. form a central hole smaller than the above cross-sectional shape,
A gear fixing structure characterized in that the gear is press-fitted and fixed to the tip of the roller shaft through the center hole.