JPH08206919A - Tooth profile generating method for hourglass worm wheel - Google Patents

Abstract

PURPOSE: To provide a generating method for the tooth profile of a hourglass worm wheel being excellent in the accurary of tooth profile without using a hourglass worm hob. CONSTITUTION: In the case of grinding the tooth profile of a copper alloy hourglass worm wheel by an electro-deposited grindstone 3 which is produced by electro-depositing abrasive grains on a thread face, and shaped in the same form as a hourglass worm screw engaging with a copper hourglass worm wheel to be groundly generated, the maximum depth of cut carried out by one piece of abrasive grain is set up less than a quarter of the mean diameter of the abrasive grain for groundly generating the hourglass worm wheel tooth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tooth profile forming method for a drum-shaped worm wheel.

[0002]

2. Description of the Related Art The gear cutting of a drum-shaped worm wheel has been carried out by a drum-shaped worm hob (see FIG. 1) or a dance cutter having a part thereof. The drum-shaped worm hob is not a screw surface of a constant lead like the cylindrical worm hob, but the number 2 on the blade side surface is almost manually required, and its tooth profile accuracy is poor. When the scooping surface is reground, the tooth profile deviates from the ideal tooth profile.

[0003]

As described above, the drum-shaped worm hob, which has been conventionally used as the method for cutting the drum-shaped worm wheel, is difficult to be removed secondly, and the drum-shaped worm hob is difficult to remove.
It was difficult to manufacture the muhob itself, and it was difficult to create an hourglass-shaped worm wheel tooth with a good tooth profile accuracy.

In view of the above problems of the prior art, the present invention provides a method for creating a tooth profile of an hourglass worm wheel having a high tooth profile accuracy without using the hourglass worm hob.

[0005]

An electroplated whetstone having a copper alloy drum-shaped worm wheel, which has the same shape as a drum-shaped worm screw that meshes with the copper alloy drum-shaped worm wheel, and in which abrasive grains are electrodeposited on the screw surface When the tooth is ground, the hourglass-shaped worm tooth is ground and finished by setting the maximum cutting depth of one abrasive grain to 1/4 or less of the average diameter of the abrasive grains. Alternatively, a copper alloy drum-shaped wheel can be formed by electrodepositing abrasive grains on the thread surface and engaging with a copper alloy drum-shaped wheel that is to be ground by an electrodeposition grindstone having the same shape as the drum-shaped worm screw. When grinding the mu-wheel tooth, the maximum cutting depth of each abrasive grain is set to be equal to or less than a quarter of the average diameter of the abrasive grain so that the hourglass-shaped worm tooth is created by grinding. In particular, tooth grinding was performed with an electrodeposition grindstone in which diamond abrasive grains or CBN abrasive grains were electrodeposited on the screw surface.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an electrodeposition grindstone 3 used in the present invention. The electrodeposition grindstone 3 has the same shape as a drum-shaped worm screw that meshes with a copper alloy drum-shaped worm wheel for tooth grinding, and abrasive grains are electrodeposited on the screw surface. Alternatively, the electrodeposition grindstone 3 has abrasive grains electrodeposited on its screw surface, and has the same shape as a drum-shaped worm screw that meshes with a copper alloy drum-shaped worm wheel to be ground. As the abrasive grains, diamond abrasive grains or CBN abrasive grains are desirable.

A drum-shaped worm wheel to create a tooth profile
The feature of the tooth material is that it is a copper alloy (for example, aluminum bronze). An electroplated diamond grindstone (or CBN grindstone) is produced by finishing this worm wheel into the same shape as the hourglass worm that meshes with it. ), The actual processing method will be described below.

The processing method is the same as the conventional hobbing method in terms of configuration. That is, on the hobbing machine 1 as shown in FIGS. 3 and 4, the electrodeposition grindstone 3 is mounted on the hob arbor 2 to which the hob is conventionally mounted, instead of the hob. The work wheel material 6 is attached to the work shaft 5 on the hobbing table 4.

In this state, the hob arbor (grinding wheel shaft) 2 and the work
The table 4 is fed in the two directions of the hob arbor shaft (grinding wheel shaft) while rotating the shaft 5 at a rotational speed ratio equal to the reduction ratio i of the worm gear set. As a result, the grinding and creation of the worm wheel by the electrodeposition grindstone 3 is started, and when the driving is completed by the height of the wheel tooth, the creation of the hourglass worm wheel is completed.

In the case of an electrodeposition grindstone, about 1/2 of the abrasive grain size is embedded in the electrodeposition layer, and the electrodeposition layer does not have voids that are convenient for removing facets. Therefore, we tried to find the condition that the grindstone would not be clogged by a grinding test. FIG. 5 shows the result of the grinding test. In FIG. 5, when the maximum cutting depth gmax of one abrasive grain is plotted on the horizontal axis and the grinding amount is plotted on the vertical axis, gmax is dw /
In the range of 4 (dw: average diameter of abrasive grains) or less, as gmax is increased, the grinding amount is increased accordingly.
It was found from the results of the grinding test that, even if gmax is increased at the boundary of = dw / 4, the grinding amount does not increase, but rather sharply decreases.

That is, it can be said that in the range of gmax> dw / 4, the electrodeposition grindstone may be clogged, which is a dangerous range. From this, when grinding teeth with an electrodeposition grindstone, the maximum cutting depth of one abrasive grain is set to 1/4 or less (gmax≤dw / 4) of the average radius of the abrasive grain, and the hourglass-shaped worm tooth is set. It can be seen that it is necessary to finish grinding. As long as this condition is satisfied, dw is at least between the electrodeposition layer and the work surface.
A / 4 gap will be created and will not clog.

[0012]

EFFECTS OF THE INVENTION Since the drum-shaped worm teeth are ground and finished with an electro-deposition grindstone, there is no decrease in the tooth profile accuracy due to the second picking and no decrease in the tooth profile accuracy due to the regrinding of the scooping surface. It is possible to create a shape-wheel tooth profile.

[Brief description of drawings]

FIG. 1 is a side view (partially sectional view) of a conventional hourglass-shaped worm hob.

FIG. 2 is a side view (partially sectional view) of the electrodeposition grindstone of the present invention.

FIG. 3 is a view (front view) for explaining the processing method by mounting the electrodeposition grindstone of the present invention on a hobbing machine.

FIG. 4 is a diagram (side view) for explaining a processing method in which the electrodeposition grindstone of the present invention is mounted on a hobbing machine.

FIG. 5 is a graph showing the relationship between the maximum cutting depth qmax of one abrasive grain and the grinding amount.

[Explanation of symbols]

1 Hobbing machine 2 Hobbing ar 3 Electroplated whetstone 4 Hob table 5 Work shaft 6 Worm wheel
Le material

Claims (3)

[Claims] 1. A copper alloy drum-shaped worm wheel having the same shape as a drum-shaped worm screw meshing with the copper alloy drum-shaped worm wheel, and tooth grinding is performed by an electrodeposition grindstone in which abrasive grains are electrodeposited on the screw surface. When
A drum-shaped worm wheel tooth profile generation method, wherein a drum-shaped worm tooth is created by grinding with a maximum cutting depth of one grain less than or equal to a quarter of the average grain size. 2. A copper alloy drum is produced by electrodepositing abrasive grains on the screw surface and meshing with a copper alloy drum-shaped worm wheel to be ground and created. When grinding a shaped worm wheel tooth, a drum-shaped worm tooth is created by grinding by setting the maximum cutting depth of one abrasive grain to 1/4 or less of the average diameter of the abrasive grain. Shape wheel Wheel tooth profile generation method. 3. The hourglass-shaped worm wheel according to claim 1 or 2, wherein tooth grinding is performed by an electrodeposition grindstone in which diamond abrasive grains or CBN abrasive grains are electrodeposited on the screw surface.
Le tooth profile creation method.