look for better plastic gear material

Ericao

A lot of thanks for your support.
I will try to modify gear's outline form and use new super higher engineering material for the life test.
Wish to be able to have good harvest.

Again, what time and condition can the lubricant of the gears running be failure? high temperature exhalation or nigrescence or ...?
Please advise.

mrmrw

塑齿传动对润滑条件还是有要求的。
如果是考虑降低噪音，则推荐使用粘度大一些的润滑脂；反之则选用难度小的润滑脂。
但是，润滑脂是否起到作用，关键是看齿轮传动过程中是否产生润滑带！

Ericao

mrmrw 发表于 2012-12-21 07:59

                               
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塑齿传动对润滑条件还是有要求的。
如果是考虑降低噪音，则推荐使用粘度大一些的润滑脂；反之则选用难度小 ...

Appreciate Mrmrw's reply.

The worm and the helical gear is point touch, my helix angle is 30.33 degree, the lubricant I selected is  bigger viscidity,

can this condition generate the lubricating film so as to reduce abrasion and noises?

woodee

so bigger helix angle, are the number of threads 4 or 5?

Ericao

woodee 发表于 2012-12-22 11:31

                               
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so bigger helix angle, are the number of threads 4 or 5?

Hi, Woodee,

The teeth number of worm are 3.

The bigger helix angle has the bigger efficiency within 35 degree for the running of worm.

Does the bigger helix angle have other aspect disadvantage?

woodee

Ericao 发表于 2012-12-22 13:34

                               
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Hi, Woodee,

The teeth number of worm are 3.

头数3，螺旋升角30.3°，这样的设计严重有问题。
1. 现有的蜗杆是否下图样子：


2. 若是的话，蜗杆齿根严重根切。如下图：


也就是说，只有齿根是如上图的形状，才能保证与齿轮啮合时不发生过渡曲线干涉。
这样的齿根形状，只有齿条型刀具如滚刀加工蜗杆时才能做到。车齿或铣齿工艺，都做不到——会出现英文所谓的under cut情况。
齿顶严重干涉，啮合不正常，或许是life test失败的另一重要原因。

Ericao

woodee 发表于 2012-12-22 15:26

                               
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头数3，螺旋升角30.3°，这样的设计严重有问题。
1. 现有的蜗杆是否下图样子：

Hi, Woodee,

My worm is involute type and its normal module is 1.25 and its tooth outline form is showed as below picture:


This worm had been made by the professional worm factory and this factory didn't believe it had the questions.

Thanks.

Ericao

woodee 发表于 2012-12-13 23:18

                               
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一般来说，金属蜗杆/塑胶齿轮副通不过寿命测试，不是磨损问题，而是强度问题。
查：
1. 是否采用蜗杆减薄 ...

Hi,Woodee,

I have modified the teeth outline form of the worm and the helical gear, it is showed as following pictures:

after modification

The factor of tooth thickness of the worm is 0.80; The factor of tooth thickness of the helical gear is 1.20,
The normal pressure angle is changed from 20 degree to 14.5 degree,
The normal module is still 1.25 and the worm is still involute type,
The teeth number of the worm and the helical gear are 3 and 27,
The helix angle is still 30.33 degree,
Their backlash is 0.05~0.10 mm.

This change, it is suitable and reliable?
Please give the comment to me.

Thanks in advance.

Ericao

woodee 发表于 2012-12-13 23:18

                               
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一般来说，金属蜗杆/塑胶齿轮副通不过寿命测试，不是磨损问题，而是强度问题。
查：
1. 是否采用蜗杆减薄 ...

Hi,Woodee,

I have modified the teeth outline form of the worm and the helical gear, it is showed as following pictures:




The factor of tooth thickness of the worm is 0.80; The factor of tooth thickness of the helical gear is 1.20,
The normal pressure angle is changed from 20 degree to 14.5 degree,
The normal module is still 1.25 and the worm is still involute type,
The helix angle is still 30.33 degree,
Their backlash is 0.05~0.10 mm.

This change, it is suitable and reliable?
Please give the comment to me.

Thanks in advance.

Sorry for resending because of the net question.

Ericao

woodee 发表于 2012-12-13 23:18

                               
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一般来说，金属蜗杆/塑胶齿轮副通不过寿命测试，不是磨损问题，而是强度问题。
查：
1. 是否采用蜗杆减薄 ...

Hi,Woodee,

I have modified the teeth outline form of the worm and the helical gear, it is showed as following pictures:




The factor of tooth thickness of the worm is 0.80; The factor of tooth thickness of the helical gear is 1.20,
The normal pressure angle is changed from 20 degree to 14.5 degree,
The normal module is still 1.25 and the worm is still involute type,
The helix angle is still 30.33 degree,
Their backlash is 0.05~0.10 mm.

This change, it is suitable and reliable?
Please give the comment to me.

Thanks in advance.

Sorry for resending because of the net question.