Tool shifting of automobile gear hobbing

The amount of channeling should be based on the maximum allowable wear of hobs. Firstly, the allowable gear hobbing channeling of hob is determined by tool modulus and machining accuracy. When the maximum wear limit is reached, it must be sharpened. The determination of gear hobbing tool shifting is through continuous test. The initial determination of gear hobbing tool channeling can usually be based on the experience of similar tools in the past. When reaching the initial channeling amount, the new task should be to improve the cutting performance under the condition of constant channeling amount, such as reducing the number, length and tooth shape of hob teeth. Due to the existence of many variables, few attempts are made to change the tool shift of gear hobbing. Instead, a maximum amount of wear is usually recommended. The setting of maximum wear will be discussed later in this chapter.

The direction of gear hob shifting depends on whether you want the hob teeth to start from the rough cutting area when making teeth, and vice versa. Usually, use the previous method. The sharp cutting edge of hob teeth is gradually loading from the rough cutting area (where the cutting load is the heaviest) to the finishing area. The profile part of the hob tooth is formed at the position of relatively light cutting load. Therefore, the tooth profile can be better improved than the rough cutting with hob.

For spur gear or small-diameter hob, by setting the rotation angle, the fine cutting gear enters the tooth profile generation area through the gear hobbing channeling in the opposite direction of the rotation direction of the hob. When the gear hobbing tool shifting direction enters the tooth shape generation area with small teeth, this method is applied to helical teeth or large-diameter hobs. Its rough cutting work is entered by sharp hob teeth, and the small cutting teeth form the tooth shape.

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