JPS6328729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a plunge cut shaving cutter for performing plunge cut shaving, and more particularly to the shape and arrangement structure of cutting edges formed on both sides of each cutter tooth.

Prior Art As is well known, there are conventional shaving methods such as conventional shaving, diagonal shaving, underpass shaving, and plunge cut shaving, among which the plunge cut shaving method is the most efficient. This processing method is said to be suitable for processing mass-produced gears. As is well known, this plunge cut shaving method does not require relative lateral feeding between the gear to be cut and the cutter, and shaving is performed only by movement of the cutter in the radial direction of the gear to be cut. The specific method of this plunge cut shaving method is as follows.

That is, as shown in FIG. 3, a plunge cut shaving cutter S, which continuously rotates in the direction of the arrow shown in the figure, is cut into the workpiece gear W, which is supported so as to freely rotate, to perform rough cutting. , When this rough cutting is completed, the cutting depth of the cutter S to the workpiece gear W is slightly returned to the workpiece gear W.
The elastic deformation of the machined surface is restored, and then the cutter S
Reverse the direction and perform finish cutting. By the way, in this plunge cut shaving method, the cutting amount due to rough cutting is 90% or more of the total cutting amount, that is, the sum of the rough cutting amount and the finishing cutting amount. In other words, in this shaving method, it is no exaggeration to say that the shaving process of the gear to be cut is performed by rotating the cutter S in one direction, and the reverse cutting of the cutter S is merely a correction work.

By the way, each cutter tooth Z of the cutter S has a plurality of cutting edges on both sides b and c, respectively, as shown in FIG.
The side surface in the direction of rotation of the cutter S is called the action surface, and the opposite surface is called the reaction surface. Therefore, in the plunge cut shaving cutter S, the gear W to be cut is machined by rotating the cutter S in one direction, so the roles of the flanks b and c of each cutter tooth Z are clearly distinguished. That will happen. That is, in FIG. 3, the tooth surface b on the rotational direction side of the cutter S becomes the action surface, and the opposite tooth surface c becomes the reaction surface.

In shaving methods other than the plunge cut shaving method, the roles of both tooth surfaces of each tooth of the cutter are not clearly distinguished as described above. That is,
In the other shaving methods described above, after the cutter cuts into the gear to be cut, the cutter is alternately rotated in forward and reverse directions. Therefore, the tooth surface that forms an action surface during forward rotation forms a reaction surface during reverse rotation.

As described above, in the plunge cut shaving method, there is a problem that the depth of cut differs on both sides of each tooth Z of the gear W to be cut due to the above-mentioned special circumstances. This state is shown in FIG. In other words, the depth of cut of the working surface _w1 of the tooth z cut by each cutting edge of the working surface b of the cutter tooth Z, that is, the amount of cutting, is F, while the cutter tooth Z
Tooth surface cut by each cutting edge Zc of reaction surface c of
The depth of cut of _w2 , that is, the cutting amount is f (<F). In this way, the working surface of each tooth z of the gear W to be cut
The reason why the amount of cutting differs between w ₁ and the reaction surface w ₂ is that the pressure applied to the action surface w ₁ of each cutting edge Zb of the cut tooth Z is greater than the pressure applied to the reaction surface w ₂ of each tooth Zc of the cut tooth Z. There's a reason why it's so big. With other shaving methods, even if such a difference in the depth of cut occurs due to one revolution of the cutter, it is corrected by the next rotation of the cutter, so there is no problem, but with the plunge cut shaving method, such a difference is not a problem. This is a problem because it is extremely small. In particular, the step D ₁ on the working surface side formed at the bottom of each tooth z of the gear W to be cut
The step D ₂ on the reaction surface side becomes unbalanced and this becomes a big problem.

By the way, when we analyze the shape and arrangement of the cutting edges Zb and Zc on the working surface b side and the reaction surface c side of each cutter tooth Z of the plunge cut shaving S, we find the following.

That is, this is extremely common knowledge in the plunge cut shaving method, but as shown in Fig. 5, the shape and shape of each cutting edge Zb on the action surface b side and each cutting edge Zc on the reaction surface c side. Their array structures are exactly the same. In other words, the cutting edge Zb
The cutting front width Tb and the cutting front width Tc of the cutting edge Zc are exactly the same dimension, and the pitch width Pb between each cutting edge Zb on the action surface b side and the pitch between each cutting edge Zc on the reaction surface c side The width Pc is exactly the same.
In other words, since the cutting edge shape and cutting edge arrangement are exactly the same on the action surface b side and the reaction surface c side, the phenomenon of the difference in the depth of cut on both sides of each tooth z of the workpiece gear W as described above is caused by I understand that it cannot be avoided.

Technical Problem Therefore, the technical problem to be solved by the present invention is to improve the cutting ability of the workpiece by mutually changing the shape of the cutting blade or the arrangement structure of the cutting blade on the action surface side and the reaction surface side of the plunge cut shaving cutter. The goal is to make sure that the depth of cut on both sides of each tooth of the gear is equal.

SUMMARY OF THE INVENTION The present inventors have focused on the fact that the depth of cut of each cutting blade into the gear to be cut is related to the surface pressure of each cutting blade to the tooth surface of the gear to be cut. That is, as this surface pressure increases, the cutting resistance increases, and therefore the amount of cutting decreases.

Based on the above idea, the present invention was constructed as follows in order to solve the above technical problem.

In other words, the total cutting front width of all the cutting edges on the working surface side of each cutter tooth is configured to be larger than the total cutting front width of all the cutting edges on the reaction surface side. The surface pressure on the tooth surface is made larger than the surface pressure on the reaction surface side cutting edge against the tooth surface of the gear to be cut, so that the depth of cut, that is, the amount of cutting on the action and reaction surfaces of each tooth of the gear to be cut, is approximately the same. I made it.

The above configuration can be achieved by the following two methods.

One of them is to focus on the tooth shape of each cutting edge, and by making the cutting front width of each cutting edge on the working surface side larger than the cutting front width of each cutting edge on the reaction surface side. be.

The second method focuses on the arrangement structure of the cutting edges, and is to make the pitch width between the cutting edges on the working surface side smaller than the pitch width between the cutting edges on the reaction surface side.

In any of the above methods, the total cutting front width of all the cutting edges on the working surface side can be made larger than the total cutting front width of all the cutting edges on the reaction surface side.

Embodiments The present invention will be specifically described below with respect to the embodiments illustrated in FIGS. 6 and 7. Incidentally, the same members as those in FIG. 5 showing the conventional example are given the same reference numerals.

First, a first embodiment will be explained based on FIG. 6.

As shown in the figure, each cutting edge Zb on the action surface b side of each cutter tooth Z and each cutting edge Zc on the reaction surface c side have mutually different shapes. That is, the cutting front width T'b of the cutting edge Zb is configured to be larger than the cutting front width Tc of the cutting edge Zc. In this embodiment, the pitch width Pb of each tooth Zb on the action surface b side is the same as the pitch width Pc between each cutting edge Zc on the reaction surface c side.

By configuring the cutting edge shape as described above, the total cutting front width T'b of all cutting edges Zb on the action surface b side is made larger than the total cutting front width Tc of each cutting edge Zc on the reaction surface c side. Therefore, the contact pressure on the working surface of each tooth of the gear to be cut on the cutting edge on the working side is greater than the contact pressure on the working surface _w2 of the cutting edge on the reaction side Zc,
Therefore, it is possible to equalize the amount of cut on the working surface side and the amount of cut on the reaction surface side of the gear W to be cut.
Conversely, the dimensional ratio of the cutting front width T'b of the cutting edge Zb and the cutting front width Tc of the cutting edge Zc is the cutting depth of each working surface w ₁ and reaction surface w ₂ of each tooth Z of the workpiece gear W. The amounts are set so that they are equal.

Next, a second embodiment will be described based on FIG. 7.

This embodiment is characterized in that the pitch width of each cutting edge is made different between the action surface b side and the reaction surface c side. That is, in this embodiment, the cutting front width Tb of the working surface side cutting edge Zb and the reaction surface side cutting edge
The cutting front width Tc of Zc is exactly the same, but on the other hand,
The pitch width P'b between the teeth on the side of the action surface b is smaller than the pitch width Pc between the cutting edges on the side of the reaction surface c.
Therefore, even with this method, the total cutting front width of all the cutting edges on the action surface b side is larger than the total cutting front width of all the cutting edges on the reaction surface c side, and as in the first embodiment, the present invention can achieve the intended purpose.

Furthermore, in any of the embodiments described above, in order to equalize the cutting depths of the action surface w ₁ and the reaction surface w ₂ of each tooth z of the workpiece gear W, the action of each cut tooth Z of the cutter S must be It is most effective if the ratio of the total cutting front width of all the cutting edges on the surface b side to the total cutting front width of all the cutting edges on the reaction surface c side is set in the range of 1:0.7 to 1:0.9.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a plunge cut shaving cutter, Fig. 2 is an enlarged perspective view showing one of the cutter teeth of the cutter in Fig. 1, and Fig. 3 shows a state where the cutter is meshed with the gear to be cut. An explanatory diagram, Fig. 4 is an explanatory diagram showing the difference in the cutting depth on the working surface and the cutting depth on the reaction surface of the tooth of the gear to be cut, and Fig. 5 shows the cutting edge on the working surface side and the cutting edge on the reaction surface side of the cutter tooth in the conventional example. FIGS. 6 and 7 are explanatory views showing the shape and arrangement structure of the cutting blades, and are similar to FIG. 5 showing an embodiment of the present invention. S...Plunge cut shaving cut, W
...gear to be cut, Z...tooth of cutter, Z...tooth of gear to be cut, Zb...cutting edge on the working surface side, Zc...cutting edge on the reaction surface side, b...working surface, c...reaction surface ,w ₁ ...
Action surface, w ₂ ... reaction surface, F, f ... depth of cut, D ₁ , D ₂ ... step, Tb, Tc, T'b ... cutting front width, Pb, Pc, P'b ... pitch width.

Claims (1)

[Scope of Claims] 1. A plunge cut shaving cutter characterized in that the total cutting front width of all the cutting edges on the working surface side of each cutter tooth is larger than the total cutting front width of all the cutting edges on the reaction surface side. 2. The plunge cut shaving cutter according to item 1, wherein the cutting front width of each cutting blade on the working surface side is larger than the cutting front width of each cutting blade on the reaction surface side. 3. The plunge cut shaving cutter according to item 1, wherein the pitch width between the cutting blades on the working surface side is smaller than the pitch width between the cutting blades on the reaction surface side.