JPH04146022A - Chamfering of gear - Google Patents

Abstract

PURPOSE:To reduce cost and labour by devising a grinding wheel to grind and process the addendum of a gear to be ground with a speed difference at the time of meshing the gear to be ground with the grinding wheel while rotating the grinding wheel fast in response to magnification of a circumferential pitch of a tool against a circular pitch of the gear to be grind. CONSTITUTION:A chamfer tool 11 which rotates so that its grinding wheel of a gear shape to engage with a gear 1 is positioned to face the gear 1 to be a gear to be ground. A circular pitch P2 of the tool 11 is to be P2=P1XK and K is a pitch magnification and is to be a value 1.0 or more in relation to the circular pitch P. of the gear 1. Since the tool teeth 14 of the tool 11 is used for addendem chamfering of the gear 1, the height H of a tooth is small, and a superposed part 21 which is a meshing part of the gear 1 and the tool 11 and where a gear outer diameter 3 and the tool outer diameter 13 are overlapped becomes a smaller area. The rotational circumferential speed of the tool 11 is enlarged by pitch magnification factor K times the rotational circumferential speed of the gear 1 so that the speed difference necessary for grinding cutting process is given. Consequently, tooth surfaces of the gear 1 and the tool 11 located at positions A1, B1, are brought in contact with each other at positions A2, B2, and chamfering process is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application> The present invention relates to a method for chamfering gears, which allows for easy chamfering of tooth tips during gear machining.

<Prior art> Conventionally, a chamfering hob 31 as shown in FIG. 4 has been used as a special tool for chamfering the tips of gears whose tooth surfaces penetrate in the tooth width direction. I was chamfering gears.

In addition, for gears with a shoulder that does not penetrate through the tooth surface, a bevel cutter 3 for chamfering as shown in Fig. 5 is used in the same way as tooth profile cutting.
2 could be considered, but it has not been used in practice because it requires applying reciprocating motion and rotational gravity to the chamfering pinion cutter 32 or the gear during cutting, resulting in inefficient processing.

On the other hand, it is also possible to use a beveled cutter 33 for tooth profile cutting with a chamfered blade 34 as shown in Fig. 6, but it would be a beveled cutter exclusively for a specific gear.
This results in poor compatibility as a tool. Therefore, since tools cannot be shared, many gear cutting tools must be prepared, leading to increased machining costs.

<Problems to be Solved by the Invention> The process of chamfering the tip of a gear tooth using the tool shown in FIG. When cutting the tooth surface 8, the chamfered surface 2 is cut at the same time, and the processing itself is efficient.

However, when producing high-mix, low-volume gears, the tools are not compatible, so many gear cutting tools must be prepared, which increases costs and requires a lot of effort to replace tools. It had drawbacks.

On the other hand, in chamfering a shoulder gear, the chamfering hob 31 shown in FIG.
The tip of tooth No. 1 could not be penetrated into the gear, and chamfering could not be performed.

In addition, the concept of so-called rolling processing, in which a gear carving tool is pressed against the gear to take the surface of the tooth tip, is the easiest processing method, but since it is based on the theory of crushing rather than scraping, The basic part of the tooth profile around the chamfer swells up, which has the disadvantage of interfering with the performance of the gear.

<Means for solving the S* problem> The gear chamfering method according to the present invention forms a gear-shaped grindstone having a circumferential pitch larger than the circular pitch of the gear to be cut,
In a gear chamfering method of chamfering the tips of the teeth of the to-be-cut gear by meshing and rotating the grindstone with the to-be-cut gear, the circumferential pitch is formed larger than the circular pitch; The present invention is characterized in that the grindstone is rotated rapidly in accordance with the magnification, and the grindstone is brought into contact with the tooth tip of the gear to be cut to chamfer the tooth tip.

Action> The grinding wheel is rotated quickly according to the ratio of the circumferential pitch of the tool to the circular pitch of the work gear, and due to the speed difference when the two mesh together, the grinding wheel comes into contact with the work gear, and the work gear A grindstone grinds the tips of the teeth and chamfers them.

Embodiment An embodiment of the gear chamfering method of the present invention is shown in FIGS. 1 and 2, and the embodiment will be described based on these figures.

As shown in FIG. 1, a chamfering tool 11 is located on the lower side of the figure, facing the gear 1 to be cut, and this tool 11 is a gear-shaped grindstone. Rotate so that it meshes with 1.

In addition, QA and Q of gear 1! The circumferential pitch P2, which is the arcuate dimension between PA and PB of the tool 11, is determined by the following formula with respect to the circular pitch P1, which is the arcuate dimension between PA and PB of the tool 11.

P = P xK Here, K means pitch magnification and takes a value of 1.0 or more, but this embodiment shows the case where P = 2.

Furthermore, since the tool tooth 14 of the tool 11 only chamfers the tooth tip of the gear 1, the tooth height H is a slight height, and as shown in FIG. A hatched portion 21, which is an overlapping portion of the gear outer diameter 3 and the tool outer diameter 13 and is a meshing portion of the gear 11, has a small area.

Moreover, the number of tool teeth of the tool 11 at this time is not particularly limited as long as it is an integer.

Chamfering of a gear using the tool 11 configured as above will be described below.

When cutting the gear 1, the tool 11 and the gear 1 rotate together while meshing with each other, but in order to provide a speed difference during rotation, the rotational peripheral speed of the tool 11 is set to a pitch multiplier relative to the rotational peripheral speed of the gear 1. Make it bigger.

As a result, a speed difference necessary for the grinding process is applied, and the tooth flank of the gear 1 at the position A1 in FIG. 1 and the tooth flank of the tool 11 at the position B1 in FIG. 1 are moved to the position A2. B
2, it will come into contact and be chamfered. Additionally, along with this, the tool teeth 14 can mesh with all the gear teeth 4.

That is, the processing method according to this embodiment easily chamfers the gear teeth 4 of the gear 1 by simply meshing and rotating the gear and the gear tool similarly to rolling, and the circular pitch P of the gear 1 , the circumferential pitch P2 of the tool 11 is increased, and the surface of the tooth tip is scraped off by the speed difference.

For helical gears, the following applies.

One ψ2−KX−ψ.

Increase the helix angle of the tool so that

However, ψ1 is the gear helix angle, and ψ2 is the tool helix angle.

Furthermore, in order to give the tool 11 an appropriate pressure angle depending on the shape of the gear chamfer surface 2, an inclination is given to the tooth surface of the tool tooth 14 formed in a linear shape or an involute curve shape, but the magnitude of this inclination is is also related to the value of pitch multiplier. That is, if the pitch magnification K is set large, the chamfered surface will be inclined greatly in the direction of the outer circumferential direction of the gear.

Furthermore, as shown in FIG. 1, depending on how the gear tooth tip chamfer position 5 where the tooth tip chamfered surface 2 is formed and the tool tooth chamfered tooth 15 of the tool tooth 14 are set, their overlapping positions are set during meshing rotation. Also, the shape of the chamfered surface changes. however,
In general, the pitch magnification K is large (I see, it is positioned closer to the meshing end 22 side within the shaded area 21 where the gear outer diameter 3 and the tool outer diameter 13 overlap shown in FIG. 2).

As shown above, after alignment is performed between the gear 1 and the tool 11, each is forcedly driven to rotate, and an arbitrary chamfer shape is machined. And gear 1 and tool 1
By rotating 1 in opposite directions, it is possible to chamfer the opposite side.

Note that during machining, the center distance between gear 1 and tool 11 is gradually brought closer to a specified cutting position to perform optimal machining.

<Effects of the Invention> According to the gear chamfering method of the present invention, a grindstone having a circumferential pitch larger than the pitch of the to-be-cut gear is meshed with the to-be-cut gear while maintaining a speed difference, and the tips of the teeth are chamfered. As a result, you will have the effect shown below.

In other words, for gears with membranes, hobbing is used, and the chamfering tool used in this case is the same worm-shaped chamfering tool used in hobbing logic, whereas for shoulder gears, hobbing is used. Since there was no dedicated tool, it was necessary to provide a chamfering blade 34 on a basic tooth profile gear cutting tool dedicated to each gear to perform chamfering, as shown in FIG.

Therefore, it was necessary to prepare tools for different numbers of teeth etc. even for gears with the same module and the same pressure angle, but with the method of the present invention, tools can be prepared for all types of gears with and without shoulders. It is now possible to chamfer by sharing tools.

From the above, in factories that produce high-mix, low-volume gears,
It is now possible to reduce costs and labor,
This is the most suitable processing method for the factory.

Further, the processing according to the present invention is not a rolling process but a grinding process, and it is possible to improve the shape accuracy of the gear. Therefore, the performance of the gear will not be affected.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the processing theory according to an embodiment of the gear chamfering method of the present invention, Fig. 2 is a diagram showing the tooth tip meshing part of Fig. 1, and Fig. 3 is a diagram of the gear having a chamfered surface. FIG. 4 is a front view of the chamfering hob, FIG. 5 is a diagram showing the main parts of the chamfering binion cutter, and FIG. 6 is a diagram showing the main parts of the binion cutter. In the drawing, 1 is a gear, 2 is a chamfered surface, 3 is a gear outer diameter, 4 is a gear tooth, 1
1 is a tool, 13 is a tool outer diameter, and 14 is a tool tooth. Figure 1 - Figure 1 Figure S1 Figure 1

Claims (1)

[Claims] Chamfering of a gear in which a gear-shaped grindstone having a circumferential pitch larger than the circular pitch of the gear to be cut is formed, and the grindstone is meshed with the gear to be cut and rotated to chamfer the tips of the teeth of the gear to be cut. In the method, the grinding wheel is rotated at a high speed corresponding to a magnification of the circumferential pitch formed to be larger than the circular pitch, and the grinding wheel is brought into contact with the tooth tip of the gear to be cut, thereby cutting the tooth tip. A gear chamfering method characterized by chamfering a gear.