JP2770487B2 - Gear tooth surface finishing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for finishing a gear tooth surface with high precision.

[Conventional technology]

The grade of finishing accuracy of gears is determined by JIS or the like. When it becomes JIS grade 1, the precision becomes severe. Normally, the tooth profile is finished with high precision by including a polishing process. By finishing the gears with high precision, the reliability and durability of the gears themselves are improved, and the backlash can be stabilized, the noise can be reduced, and the mechanical loss can be reduced while the gears are meshed.

If it is only necessary to improve the finishing accuracy of the gears, it is possible to finish the gears to the accuracy of the first class if it takes time even with gear cutting with a hob. However, in the case of a gear having a high hardness by heat treatment, cutting with a hob becomes impossible. There is also a method called “Sky Beeg” for finishing carburized gears, but the finishing accuracy is only about 1.5 to 1.2 grade.

To finish gears that have been thermally deformed during carburizing with high precision,
Although it uses grinder polishing, it takes a long time to process and the processing cost increases.

When such a high-precision gear is used, unless the assembly dimensional accuracy of the gear mounting shaft, bearing, support case, and the like is also high, there is no point in manufacturing the gear with high precision.

As described above, in a method of assembling the gears in a state of being engaged with the support case, a gear is manufactured with a small backlash so that the backlash is close to zero, with a precision of the second to third grades. There is a method in which diamond powder is put into a meshed gear by rotating it while assembling it in a support case to be actually assembled, and the gears are polished and formed together.

[Problems to be solved by the invention]

In the above method, since the grinding is performed in a state where it is actually assembled in a case to be assembled, an assembly error is absorbed, and
There is an advantage that high accuracy can be obtained in a relatively short time of about 10 to 20 minutes. However. On the other hand, the diamond powder used for grinding bites into the tooth surface, and the diamond powder cannot be completely removed even with careful cleaning, and the tooth surface of the gear is damaged early by the remaining diamond powder. There's a problem.

An object of the present invention is to solve the above-mentioned problems and to provide a gear tooth surface finishing method capable of obtaining a durable high-precision gear at a low cost by eliminating the influence of diamond powder remaining on the gear tooth surface. Things.

[Means and actions for solving the problem]

According to the present invention, a gear processed so that the backlash is substantially zero is rotated while providing an abrasive in a state in which the gear is meshed with a mating gear, the noise during the rotation is reduced, and the backlash is increased by a predetermined amount. This is a gear tooth surface finishing method in which the rotation is sometimes stopped and a coating having a thickness corresponding to the increased backlash is applied to the tooth surface of the gear after the cleaning process.

Although the gear train makes a loud noise at the beginning of the rotation of the meshed gears, the sound becomes quiet when both gears are familiar and well meshed. Further, the conforming rotation is continued until the tooth profile surface is ground and the backlash increases by a predetermined amount.

After the break-in rotation has been stopped and the cleaning process has been performed, the bitten abrasive material remains on the tooth profile surface of the gear. By uniformly coating the tooth profile surface of the gear with an extra-ground thickness, the abrasive remaining on the tooth profile surface is not wrapped by the coating material and does not come out on the meshing surface of the gear. The meshing surfaces of the gears are restored to a state in which the two gears, whose sound has become quiet during rotation, are in maximum meshing with each other, so that the gears mesh extremely smoothly.

〔Example〕

 Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view of the finishing step of the present invention, and FIG. 4 is a perspective view showing a familiar rotation. As shown in FIG. 4, a gear 5 and a gear 3 which have been processed and heat-treated to the second order of accuracy are mounted on their respective shafts 2 and 4, and are actually assembled as indicated by broken lines.
And assembled with bearings 6 and 7.

The gear 1 is machined so that the backlash of the tooth profile surface 1a is substantially zero as shown by # 1 in FIG. 1 and is smaller than the one-dot chain line 10 indicating the meshing line with the regular backlash. , Heat-treated. The same applies to the gear 3.

In FIG. 4, a mixture of the lubricating oil and the diamond powder 8 is supplied to the meshing portion between the gear 1 and the gear 3, and both gears are rotated to perform a familiar rotation. At this time, the bearing of case 5
For 6,7, lubrication of lubricating oil of another system alone will be implemented.

As shown in FIG. 2, the gear train makes a loud noise at the beginning of the familiar rotation (see # 2 in FIG. 1), but becomes quiet at time t ₁ (about 20 minutes) after continuing the familiar rotation. . At this time, the two gears 1 and 3 are in a state of being in maximum meshing with each other.
At t ₂ (about 10 minutes) after continuing the familiar rotation, the sound becomes slightly higher. In this state, as shown in FIG. 3, the tooth profile surface is excessively ground by the thickness D, and the circumferential backlash increases more than a specified amount (see # 3 in FIG. 1).
The engagement between the two gears is smooth. In this state, the familiar rotation is stopped.

Next, the two gears 1 and 3 are washed, but as shown in FIG. 5, the diamond powder 8 biting into the tooth profile surface 1a cannot be completely removed, and the diamond powder 8 remains in some places. (See # 4 in FIG. 1).

Next, as shown by # 5 in FIG. 1, a coating 9 having a thickness D is uniformly applied to the surfaces of both gears 1 and 3. Material Kotengu is selected in accordance with _{T i N, T i B,} BN, use conditions of the gears from the WC, etc., the method of Kotengu as sputtering, chemical vapor deposition (CVD), ion grating or the like can be used.

As described below, the diamond powder used at the time of the familiarizing rotation remains on the tooth profile surface even after cleaning the gear, but a coating layer of a predetermined thickness is applied thereon, as shown in FIG. 6, The diamond powder is wrapped and does not come out of the gear meshing surface, and the gear meshing surface is restored to a state where both gears are quietly engaged in the familiar rotation and the two gears mesh best Therefore, the meshing can be performed very smoothly.

Even if the tooth trace etc. of each gear deviates from the regular size due to the familiar polishing rotation, the gear meshing with this will deform correspondingly and adapt, so smooth meshing is guaranteed, stabilization of backlash, Noise can be reduced and mechanical loss can be reduced.

The abrasive is not limited to diamond powder, and other abrasives can be used, and a special case for performing a conventional polishing rotation can also be used.

〔The invention's effect〕

The present invention can finish gears processed with low precision in a short time by simple means, stabilize backlash in a state where the gears are engaged, reduce noise, reduce mechanical loss, etc., and achieve durability. There is an effect that a certain high-precision gear can be obtained at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of a finishing process of the present invention, FIG. 2 is a diagram showing a change in sound during a familiar rotation, FIG. 3 is a diagram showing a change in backlash due to a familiar rotation, FIG. FIG. 4 is a perspective view showing a familiar rotation, FIG. 5 is an enlarged perspective view showing the tooth profile surface after cleaning, and FIG. 6 is an enlarged perspective view showing the tooth profile surface after coating. 1,3: machined gear, 1a: tooth surface 2,4: fixed shaft, 5: case 6,7: bearing, 8: diamond powder 9: coating layer

Claims (1)

(57) [Claims] 1. A gear machined so that the backlash is substantially zero is rotated while supplying an abrasive while meshing with a counterpart gear, and the noise during the rotation is reduced and the backlash is increased by a predetermined amount. A method of finishing the tooth surface of a gear, wherein the rotation is stopped when the gear is rotated, and a coating having a thickness corresponding to the increased backlash is applied to the tooth surface of the gear after the cleaning process.