### How to test the accuracy of the gears ?

- Dec 13, 2019-

Accuracy detection and accuracy classification of products before pairing

For the conventional manufacturing process of spiral bevel gears, accuracy testing is generally not performed before pairing. The accuracy of each paired product is summarized to show whether the product's matching accuracy is qualified.

For users who do not have a T20 pairing machine, the accuracy of the helical bevel gears is completely randomly combined. For the BJ130 spiral bevel gear, the drawing stipulates that the radial runout of the ring gear of the large wheel is 0.11 mm, that of the small wheel is 0.065 mm, and the amount of backlash change is 0.15 mm. In order to ensure the precision of the product, the detailed method is:

(1) For the BJ130 spiral bevel gear, the large and small wheels are respectively subjected to all inspections of the ring gear radial runout to find out the products with acceptable accuracy of the spiral bevel gear, and then pairing.

(2) In order to improve the matching rate of the product, Olikon's skkz knife adjuster was converted into a ring gear runout tester to improve the detection rate. After the modification, one person can measure 150 to 170 BJ130 large wheels per shift.

According to the data situation of the T20 detector, the following rules were found:

ΔFrΣ = ΔFrA + ΔFrB (1)

Where ΔFrΣ——the sum of the radial runout of the ring gears of the big and small wheels, mm

ΔFrA——Radial runout of large ring gear, mm

ΔFrB——Radial runout of small ring gear, mm

According to formula (1), for BJ130 spiral bevel gear, ΔFrΣ = 0.175 mm. According to the detailed situation, we divide the radial runout of the big and small wheels into 6 categories.

Big wheel

≤0.05

0.05 ～ 0.08

0.09 ～ 0.11

0.12 ～ 0.13

0.14 ～ 0.15

≥0.15

Ferry

≤0.02

0.03

0.04 ～ 0.07

0.08 ～ 0.10

0.11 ～ 0.15

≥0.15

To satisfy the requirements of ΔFrΣ = 0.175 mm≈0.18 mm, we use the following combination of methods for BJ130 spiral bevel gears:

① (0.14 ～ 0.15) mm + 0.02 mm = (0.16 ～ 0.17) mm, accounting for about 10%.

② (0.12 ～ 0.13) mm + 0.03 mm = (0.15 ～ 0.16) mm, accounting for about 20%.

③ (0.09 ～ 0.11) mm + (0.04 ＋ 0.07) mm = (0.13 ～ 0.18) mm, accounting for about 60%.

④ (0.05 ～ 0.08) mm + (0.08 ＋ 0.10) mm = (0.13 ～ 0.18) mm, accounting for about 5%.

The accuracy of the remaining non-supporting vehicles is determined as ΔFrΣ≈0.18 mm ～ 0.24 mm, accounting for about 5%.