JPS5943254B2 - Equipment for manufacturing or processing spur gears - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing or processing, especially for grinding, straight or helical spur gears, comprising at least one tool having teeth and forming a rotating body. , in which one tool, acting partly as a forming tool and partly as a transfer tool by the plunge cut method, engages with the workpiece at an angle of intersection of the axes greater than 35°.

A method of grinding gears similar to hobbing is already known, and according to this method the tool is a single cylindrical worm, which rolls on the teeth of the workpiece e7.

In this method, the tool must be moved longitudinally relative to the workpiece, which requires machining time and must therefore be avoided (German Patent No. 841
(See specification No. 986).

It is also known to use so-called worm-like shaped tools for hob grinding.

Whereas in the case of the cylindrical worm mentioned above, whose axial section corresponds to one rank and the tooth flanks of the workpiece and the tool, at least theoretically, contact only at one point, the worm The teeth of the shaped worm are in close contact with the tooth surfaces of the workpiece, and the worm corresponds to a forming tool that rolls over the teeth of the workpiece.

This tool, however, is not designed to work in the plunge cut method, so a longitudinal feed still has to be carried out (see US Pat. No. 1,759,333).

Tools for grinding, in particular honing, hardened gears are also known, which tools are configured as grinding gears and
The axis makes an intersecting angle of not more than 30° with the axis of the workpiece during machining, and vertical feeding is performed during machining.

Apart from the time-consuming vertical feed, the disadvantage of this tool is that its useful life in practice is too short.

Furthermore, due to the small axis intersection angle, the sliding speed along the tooth is small compared to the sliding speed in the tooth depth direction.

The sliding speed in the tooth depth direction exhibits a known difference during gear shifting, being large at the tooth tip and tooth root and equal to zero within the rolling circle.

This results in different material removal over the entire tooth depth.

Such a difference cannot be reduced by the aforementioned small longitudinal slip, which is approximately the same over the entire tooth depth.

Therefore, such gear honing is difficult to carry out (see German Patent No. 915,174).

The apparatuses of the type mentioned at the outset that have already been proposed are aimed at making it possible to machine workpieces as quickly as possible.

One possibility for speeding up the work consists in avoiding longitudinal feeding of the tool relative to the workpiece along the teeth.

Another possibility lies in shortening the tool change time, by increasing the service life of the tool, in other words so that the tool itself does not have to be replaced as often.

These two possibilities must be combined as much as possible.

In addition to this, it is possible to reduce the difference between material removal at the root and end of the tooth and material removal at the rolling circle.

The proposal for a device of the type mentioned at the outset shows that this problem is solved when one tool, acting partly as a forming tool and partly as a transfer tool, by the plunge cut method has an axes intersection of more than 35°. Solved by engaging the workpiece at an angle.

Plunge cutting is a method in which the tool only produces a cutting feed relative to the workpiece.

■According to the embodiment, the device is composed of one gear-shaped tool having rolling elements of a hyperboloid shape or a similar shape, and the generatrix of this rolling element is the rolling element (rolling cylinder) of the workpiece.
, and in this case relative to the theoretically correct shape of the generatrix, the rolling elements can be deflected in such a way that they have a shape that deviates from the hyperboloid corresponding to the angle or modification of the teeth of the workpiece.

As a result, known modifications can be made to the teeth of the workpiece.

This modification is, for example, the so-called crowning of the tooth,
In short, the teeth are made slightly thicker at the center of the gear than at both end faces.

In addition, in the case of such a proposal, the device can also be advantageously constructed with one worm-shaped worm which engages with the workpiece at an angle of intersection of the axes deviating from 900.

In such a proposal, the angle of intersection of the workpiece spindle axis and the tool spindle axis and the axial dimension of the tool are set so that the teeth of the tool and workpiece mesh from one end surface of the workpiece to the other end surface. This is particularly important for the purpose of avoiding longitudinal feed.

Whether a hyperboloid-shaped or a lattice-shaped tool is used depends largely on the angle of the teeth of the workpiece and the desired sliding conditions on the tooth flanks.

The use of the tool to sharpen the tool is also important if the tool is a grinding tool.

In the case of hyperboloid shaped tools, known linearly moved sharpening tools can be used.

Rather than being moved parallel to the tool axis, as is the case with a cylindrical worm, it is moved obliquely to the tool axis, that is, in the direction of the generatrix of the hyperboloid.

Sharpening can also be carried out using a sharpening tool that has the shape of the workpiece or a part thereof.

In the case of tools in the form of worms, the sharpening tool may be used according to known methods for making worms.

It is also possible to use a sharpening tool that has the shape of the workpiece or a part thereof.

The particular advantages of the tool proposed above for a device of the type mentioned at the outset are as follows.

That is, compared to known gear-shaped honing tools, it has a longer service life due to its larger effective surface, and therefore, unlike known honing tools, it is possible to modify the tooth flanks of hardened gears in a mass-produced manner. Is Rukoto.

Due to its plunge cutting method, the proposed device has the advantage of short machining time, unlike grinding with a cylindrical grinding worm.

This is because vertical feeding can be avoided.

Such tools are particularly suitable for precision machining after pre-machining such as gear cutting.

By the way, the above-mentioned tools or devices are not intended to machine the entire face width of the workpiece.

This is because plunge and cut operations are performed at an axis intersection angle greater than 30°.

The object of the invention is to provide a device or tool of the type mentioned at the outset, which is suitable for large axis intersection angles and for virtually all workpiece face widths.

This problem is achieved according to the invention by means of a device having the characteristics of claim 1.

If the axis intersection angle is larger than the value set in claim 1, the tooth surface of the workpiece tooth will not be machined over its entire width.

Therefore, the feature of claim 2 is also important.

The invention will now be explained with reference to the embodiment shown in the drawings: The tool 1 schematically shown in FIG.
It may be a two-string worm.

The tool 1 is exchangeably mounted on a tool spindle 2, which is not shown schematically.

The fixing means and drive for the tool spindle 2 are well known and are therefore not shown.

The tool 1 meshes with a straight toothed or helical toothed tool 3.

This workpiece 3 is exchangeably fixed on a workpiece spindle 4.

The illustrated device can be constructed in such a way that both main shafts are driven, e.g. a drive connection between the artist shafts or the two main shafts are connected to one another via one so-called electric transmission shaft. good.

Alternatively, only one spindle can be driven, and the other spindle can be carried along by the workpiece and the teeth of the tool.

Because the workpiece has the above-described shape, the tooth flanks of the teeth 5 of the tool come into close contact with the tooth flanks of the workpiece teeth 6.

This makes it possible to arrange a part of the workpiece, for example the front part, in any part of the tool, for example the left part in FIG.

This is achieved by arranging the tool spindle and workpiece spindle as follows.

That is, unlike the usual worm drive, both spindles are
They are made to intersect at intervals smaller than °.

In this case, deviations from the right angle, which usually occur with worm-shaped tools, are presupposed as a result of the angle of the workpiece and of the teeth of the tool.

This means that, in addition to the crossing of the axes required for the tooth angles mentioned above, the two axes are additionally crossed.

The effective range of the teeth of the tool thus extends from one end face 7 of the workpiece to the other end face 8, so that a feed similar to a plunge cut, ie a radial variation of the spindle spacing, is sufficient for machining.

The tool may be made of the same material as a conventional grinding tool or honing gear.

It may also be a metal body with diamond grains.

It should be noted that the invention can also be applied to milling if the tool is made of a suitable material and has a chip groove.

FIG. 2 shows an embodiment using a tool 9 having a hyperboloid shape.

The tool spindle 2 forms an axis intersection angle 10 with respect to the workpiece spindle 4, which axis intersection angle 10 is greater than 30° in order to ensure sufficient longitudinal slip on one side, and on the other side to ensure sufficient longitudinal slippage. 90° in order to be able to plunge cut the object over its entire width (from end face γ to end face 8)
significantly smaller than

The effective width of the tool is indicated by a broken line LL12.

The teeth of the tool run along the generatrix 14 of the hyperboloid in the case of straight tooth workpieces.

It is also possible to modify the tooth surface of the tool in the longitudinal direction so that the workpiece 3 has a helical cut or a desired crowning (rounding in the direction of the tooth trace).

FIG. 3 shows an embodiment in which a claw-shaped worm 13 is used as a tool.

In this example as well, the axis intersection angle 10 differs from the customary 90° in the case of claw-shaped worms, so that the workpiece can be machined over its entire width without longitudinal feed, i.e. following a plunge cut. Machining is performed by applying radial feed to the main axis of the object and tool.

When trying to apply crowning to a tooth using a worm (see Figure 3), it is also possible to give the workpiece a small additional movement relative to the tool, which causes the main axis of the workpiece to This is possible by swinging within a plane perpendicular to the drawing plane of FIG.

In the case of the tools described above and similar known tools, the ratio of the tooth size of the workpiece to the tool has not received sufficient attention.

Therefore, the workpiece may be machined into an unfavorable shape or the tooth surface may be left unmachined.

If the tooth size is in the relationship according to the following formula, the tooth surface of the workpiece will be machined perfectly.

That is, the equation is as follows, where zw is the number of teeth of the tool, and dw is the diameter of the pinch circle or rolling circle of the tool, which can be almost freely selected.

The intersection angle γ of the axes between the workpiece and the tool is obtained from the relational expression, where s is the face width and ek is ekl
Or it is a large division of ek2 (Figure 4).

ekl is a projection of the portion of the meshing length e from the pinch point C to the tip point k onto a plane 20 extending perpendicularly on a common perpendicular line 19 to the axes of the workpiece and tool.

ek2 is the projection of the portion of the engagement length e from the pinch point C to the dedendum point A onto the plane.

The root point A is defined by the engagement length e and the diameter (true involute diameter) dTIF.

The intersecting angle of the axes can thus lie between 35° and γmax, in which case the tool must be wide enough to span the entire width of the workpiece.

Note that daw is the tip circle diameter of the tool, and dgw is the base circle diameter.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the engagement of a hyperboloid-shaped or lattice-shaped tool with the teeth of a straight-toothed or helical-toothed workpiece, and Fig. 2 is a diagram showing the engagement of a hyperboloid-shaped tool with a straight-toothed workpiece. FIG. 3 is a schematic view showing the working relationship of the mesh worm on a straight tooth workpiece, and FIG. 4 is a diagram showing the engagement length between the tool and the workpiece. 1...Tool, 2...Tool spindle, 3...
... Workpiece, 4 ... Workpiece spindle, 5 ...
...Tooth of tool, 6...Teeth of workpiece, 9...
...Hyperboloid shaped tool, 10...Axes intersecting angle, 13...Tsut-shaped worm.

Claims (1)

[Scope of Claims] 1. A device for manufacturing or processing straight toothed or helical toothed spur gears, comprising at least one tool having teeth and forming one rotating body; For forming tools, some of which work as transfer tools by the plunge cut method, in which one tool engages with the workpiece at an axis intersection angle greater than 35°, the number of teeth of the tool is 1.
and other values that define the engagement with the workpiece 3, there is a relationship as shown in the formula, where dw is the pitch circle diameter or rolling circle diameter to be selected of the tool, mn is the module Bz is the pitch circle or rolling circle inclination angle, γmax
is the maximum permissible axis intersection angle, α is the engagement angle (pressure angle) in the pitch circle, α is the engagement angle (pressure angle) in the rolling circle, and in this case, b7. is the face width of the workpiece, ek is the large division of ekl or ek2, and ekl is the part of the engagement length e from the pitch point C to the tooth tip point K, which is a plane 20, that is, with respect to the axes of both the workpiece and the tool. A plane 2 extending at right angles on a common perpendicular line 19
0 Projection shifted upward, ek2 is the engagement length e internal tooth light point A
ekt-like projection of a portion defined by: An apparatus for making or processing a spur gear, characterized in that: 2. The apparatus according to claim 1, wherein bw is the tool width.