JPS6059092B2 - Helical gear shape cutting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a generation method using a pinion cutter, and in particular, the present invention relates to a generation method using a pinion cutter, and in particular, by replacing only the cutter without replacing the helical guide attached to a gear shaping machine, and without replacing the slider or ider, an arbitrary helix angle and an arbitrary shape can be achieved. It is possible to cut a helical gear having a module of

When cutting a helical gear with a conventional gear shaper, as shown in the cutter head in Fig. 1, a pinion with the same helix angle as the helix angle formed on the gear material (not shown) and in the opposite torsion direction is used. Use cutter 1.

Further, a cutter shaft 2 to which this pinion cutter 1 is attached is attached to a slider 4 guided by a helical guide 3, and performs a spiral reciprocating cutting motion along the helical groove of the helical guide 3. At this time, the lead L of the helical groove carved in the helical guide 3 is determined by the tooth normal module mn and the helix angle 4 defined in the gear material. In other words, the tooth normal module and the torsion angle of the pinion cutter 1 attached to the cutter shaft 2 which threadably moves along the helical groove of the helical guide 3 are also set to the same value as the value set for the gear material, respectively mn)ψ Therefore, the spiral lead L can be obtained by the following equation (1). mnIZ, π L=, ...... (1) slnφ L: Spiral lead of helical guide (Tfrm)
mn: Pinion cutter right angle module (Tm) Z:
Number of teeth of the pinion cutter φ: Torsion angle of the pinion cutter (degrees) The spiral lead L of the above-mentioned helical guide is also determined by the number of teeth Z of the pinion cutter. When ψ is changed, even if the number of teeth Z, which can only take natural number values, is changed, the spiral lead L cannot necessarily be the same value as before the change.

Therefore, the tooth normal module mn and helix angle ψ of the gear material
When the helical guide changes, not only the pinion cutter but also the helical guide with a different spiral lead L and the slider leading thereto are usually replaced accordingly. However, replacing the helical guide and slider not only takes time, but also requires skill for adjustment, which is a major factor in reducing work efficiency. Moreover, the helical guides and sliders themselves are expensive, and it is very uneconomical to have to prepare a large number of them. Therefore, an object of the present invention is to eliminate this drawback and provide a method for cutting various types of helical gears with different helical angles using a pair of helical guides and sliders. This is intended to reduce costs.

The structure of the present invention that achieves this object is such that the cutter shaft to which the pinion cutter is attached reciprocates with respect to the gear material along the helical groove of a constant lead L carved in the helical guide. When rotating the gear material synchronously to form the gear material into a helical gear with a helical angle of ψ and a normal module of Mn, the gear has a pitch diameter of nψ and a circular pitch of Mn-π. The pinion cutter is provided with a plurality of incisors forming a section, and the distance between the incisors is M.

- The gear material is characterized in that the gear material is gear-cut at the portion that becomes π. In other words, the present invention widens the limited range of the number of teeth Z of the pinion cutter in order to enable cutting of helical gears of arbitrary specifications with a pair of helical guide and slider, and the number of teeth Z of the pinion cutter is It is expressed by modifying the previous equation (1) as shown in the following equation (2). Therefore, if the spiral lead L is a fixed value, changes in the normal angle module Mn and the torsion angle ψ will include decimal values. There will be times when this becomes a thing.

In the past, it was naturally impossible to have a gear with a decimal number of teeth like this, but in the present invention, it is assumed that a gear with a decimal number of teeth exists. Then, the pitch circle diameter d of the pinion cutter is determined from the fixed value (constant) of the spiral lead L and the helix angle ψ determined from the gear material. Act as a representative.

This (has a pitch circle diameter d determined by the 3Y formula,
In addition, by using a special pinion cutter having the same normal tooth angle module Mn and helix angle ψ as the gear material, generating gear cutting can be performed by converting only the pinion cutter without changing the spiral lead L. However, the above-mentioned special pinion cutter has a tooth space value M larger than Mn·π/2.・There may be a spot smaller than π, or a spot with an incomplete tooth profile. If an incomplete tooth is to be formed, this is removed and the tooth groove is made Mn-π/2.
It is preferable that the location has a value larger than . For example, the number of teeth is 11. As shown in Figure 2, if the value is calculated as Mn-
Since the pinion cutter 1'' forms a tooth groove of π/2 or more, it is better to perform gear cutting at the part of the complete incisor 5 where the tooth spacing is Mn-π.In other words, the complete incisor The circular pitch of the part forming 5 is equal to the circular pitch of the gear material, and the value is Mn-π, but only the circular pitch between the complete incisors 5 through the part where the incomplete incisors are removed is different from this. The values are different.Of course, it is possible to create the gear by reducing the number of teeth to 11 or less and cutting the complete incisors.In manufacturing this pinion cutter, By using an index plate that matches the design of the pinion cutter, it can be easily manufactured.One feature of the method of the present invention is that it uses the above-mentioned pinion cutter, and the gear material can be arbitrarily set. Pitch circle diameter d = (L/π) made according to the tooth normal module Mn and torsion angle ψ
A Tanψ pinion cutter is attached to the cutter shaft, and generating and cutting movements are performed in the conventional manner only at the portion where the incisor spacing is Mn·π.

When a part of the pinion cutter with a different tooth groove value approaches the gear material, the gear material is moved away from the pinion cutter and the generating recirculation motion of both the cutter shaft and work table is reversed in rapid traverse to cut it. It is better to return to the starting point, cut again, and restart the creation movement. Alternatively, when the part where the tooth space value differs from the others approaches the gear material, move the work table away from the pinion cutter, then rotate the pinion cutter in the same rotational direction in rapid traverse to pass this part and cut again. It is also possible to continue the generating motion from the incisors with an equicircular pitch of Mn-π, but in this case, it is possible to continue the generating motion from the incisors with equal circular pitches of Mn-π, but at this time, it is necessary to adjust the phase of the points where the tooth gap values are different between the cutter axis and the work table. It is necessary to correct it. These discontinuous rotational movements between the cutter shaft and the work table can be easily performed by setting them in advance when both are driven by NC. Also, of course,
If the number of teeth Z is a natural number from the above formula (2),
It is possible to perform the conventional generating motion with a very ordinary pinion cutter. As explained above,
The method according to the present invention uses a special pinion cutter on a gear shaper that has one part where the tooth space value is different from the other to perform a discontinuous generating motion, thereby eliminating troublesome and difficult helical guides and sliders. It is now possible to cut many types of helical gears with different helix angles by simply replacing the pinion cutter.

Moreover, it also contributes to reducing processing costs.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional structure diagram of a cutter head of a general gear shaper, and Fig. 2 is a perspective view showing an embodiment of a pinion cutter used in the present invention. , 3 is a helical guide, 2 is a cutter shaft, 4 is a slider, and 5 is an incisor.

Claims (1)

[Claims] 1. While reciprocating the cutter shaft to which the pinion cutter is attached to the gear material along a helical groove of a constant lead L carved in the helical guide, the cutter shaft and the gear material are synchronously rotated to remove the gear material. When forming into a helical gear with a helical angle of ψ and a normal module of m_n,
The pinion cutter is provided with a plurality of incisors having a pitch circle diameter of (L/π) tanψ and forming a part where the circular pitch is m_n·π, and the interval between the incisors is m
A helical gear shaping method characterized in that the gear material is gear-cut at a portion where the shape becomes _n·π.