The double replacement type pre-grinding hob
Affiliated technical field: the utility model relates to a kind of double replacement type pre-grinding hob.
Background technology: at present, all gear manufactories are when producing gear with common pre-grinding hob, and the bigger problem of easement curve faceted pebble all can appear in the gear teeth root.This is because common pre-grinding hob is a kind of generating tool, all can form one section easement curve at the gear teeth root during gear hobbing, and this phenomenon is that all generating tools all can't overcome.And this section easement curve faceted pebble in the back operation reprocess.Especially during the gear of the big modulus of gear hobbing, few number of teeth, the problem that the easement curve faceted pebble of gear teeth root is bigger is more serious.And bigger easement curve faceted pebble has not only reduced the intensity of gear, and has had a strong impact on the attractive in appearance of service life of gear and gear shape.Therefore, domestic all hobboing cutter manufacturers all reduce the method for gear teeth root faceted pebble in research, for example adopt the pressure angle pre-grinding hob that diminishes, and reduce gear teeth root faceted pebble by the method that increases the pre-grinding hob registration.But all method effects are not clearly.Have only the number of teeth that increases pre-grinding hob, thereby the method effect of the round cut number of teeth of pre-grinding hob is best when increasing the gear hobbing gear.But the reason that common pre-grinding hob is subjected to cutter structure and gear hobbing lathe can hold aspects such as hobboing cutter maximum gauge limits, it is very big that the pre-grinding hob external diameter can not be done, so the number of teeth that common pre-grinding hob can be made is limited, even the pre-grinding hob external diameter is accomplished maximum, the number of teeth that common pre-grinding hob can increase also seldom can't overcome this objective reality at all.
Summary of the invention: the purpose of this utility model provides and a kind ofly can not only guarantee normal profile accuracy, and can reach the double replacement type pre-grinding hob that reduces gear teeth root faceted pebble well.The purpose of this utility model realizes by following structure: the utility model is a kind of double replacement type pre-grinding hob, a little tooth is left at the tooth root rear portion of pre-grinding hob orthodont, this little tooth is the profile of tooth of pre-grinding hob tooth top, the original orthodont of pre-grinding hob is called nipper, and the little tooth that the tooth root rear portion of pre-grinding hob orthodont is left is called the back tooth.By increasing the pre-grinding hob round cut number of teeth of gear teeth root, reach the purpose that reduces gear teeth root faceted pebble.Because it is very big that common pre-grinding hob external diameter can not be done, and the easement curve faceted pebble all produces at the gear teeth root, and therefore how can increase pre-grinding hob is crucial in the round cut number of teeth of gear teeth root.Therefore we leave a little tooth at the tooth root rear portion of common pre-grinding hob orthodont, and this little tooth only guarantees the profile of tooth of pre-grinding hob tooth top, and does not make the profile of tooth of pre-grinding hob pressure angle.So just make the tooth root portion of gear increase by one times at gear hobbing hour wheel cutting number.We are called nipper to the original orthodont of pre-grinding hob, and the little tooth that the tooth root rear portion of pre-grinding hob orthodont is left is called the back tooth.The pre-grinding hob of this structure is called the double replacement type pre-grinding hob.In order to utilize domestic existing equipment to process this double replacement type pre-grinding hob and to make things convenient for the reconditioning of user to the double replacement type pre-grinding hob, we design the nipper of double replacement type pre-grinding hob and back tooth on same equal portions, but cause the back tooth too thin so again.For the width of tooth after increasing, thereby the intensity of tooth behind the reinforcement double replacement type pre-grinding hob becomes different angles to nipper with back land ditch angle design in the design targetedly, has guaranteed that back tooth has enough intensity.Through the checking computations that repeatedly combine, at last the nipper flute angle of double replacement type pre-grinding hob is designed to θ with relieving cam
1(14 °<θ
1<16 °), back land ditch angle is designed to θ
2(20 °<θ
1<30 °).And front and rear teeth is distributed on 20 five equilibriums, the front and back tooth respectively accounts for 10 five equilibriums.The beneficial effects of the utility model are: not increasing under the normal hobboing cutter external diameter situation, can not only guarantee normal profile accuracy, and can solve the gear teeth root well and the bigger problem of faceted pebble occurs.And, make the double replacement type pre-grinding hob more steady, more brisk when the gear hobbing gear owing to increased the number of teeth of pre-grinding hob relatively, and the gear teeth face that rolling cut goes out is Paint Gloss, and the problem that tooth root portion faceted pebble is big alleviates greatly.Also improve simultaneously the anti-wear performance of hobboing cutter, prolonged the service life of hobboing cutter.
Description of drawings:
Accompanying drawing 1 is that the double replacement type pre-grinding hob is made the front view in the sketch.
Accompanying drawing 2 is that the double replacement type pre-grinding hob is made the side view in the sketch.
Accompanying drawing 3 is that the double replacement type pre-grinding hob is made the nipper axial tooth profile figure in the sketch.
Accompanying drawing 4 is that the double replacement type pre-grinding hob is made the back tooth axial tooth profile figure in the sketch.
Accompanying drawing 5 is complete cutter tooth of double replacement type pre-grinding hob (nipper and one after tooth)
The specific embodiment:
The utility model as shown in Figure 1 is a kind of double replacement type pre-grinding hob, a little tooth is left at the tooth root rear portion of pre-grinding hob orthodont, this little tooth is the profile of tooth of pre-grinding hob tooth top, the original orthodont of pre-grinding hob is called nipper 1, and the little tooth that the tooth root rear portion of pre-grinding hob orthodont is left is called back tooth 2.The nipper 1 of pre-grinding hob all designs on same equal portions with back tooth 2, and nipper is different angles with back land ditch angle, and the nipper flute angle of pre-grinding hob is θ
1(14 °<θ
1<16 °), back land ditch angle is θ
2(20 °<θ
1<30 °), and front and rear teeth is distributed on 20 five equilibriums, the front and back tooth respectively accounts for 10 five equilibriums.
In accompanying drawing 1 illustrated embodiment, what the front view in the manufacturing sketch mainly marked is the contour dimension of double replacement type pre-grinding hob, comprises the external diameter of double replacement type pre-grinding hob, length, the empty cutter size of endoporus, and pillow block external diameter, pillow block height and endoporus mating surface length.
In accompanying drawing 2 illustrated embodiments, what the side view in the manufacturing sketch mainly marked is endoporus and the endoporus relative dimensions and the knife-tooth structure size of double replacement type pre-grinding hob.Wherein the size that marked of double replacement type pre-grinding hob endoporus and endoporus relative dimensions all is the national standard size.Substantially all be labeled on the knife-tooth structure size and the utility model structure is different from the place of common pre-grinding hob structure, the flute angle is θ
1Be preceding cutter tooth flute angle, the flute angle is θ
2Be cutter tooth flute angle, back, the front and back cutter tooth is distributed on 20 five equilibriums, and the front and back tooth respectively accounts for 10 five equilibriums.The preceding cutter tooth flute degree of depth and the back cutter tooth flute degree of depth also all are labeled on the side view of making in the sketch, and their occurrence produces back of the body amount by profile of tooth height dimension and cutter tooth and calculates.
In accompanying drawing 3 illustrated embodiments, what the nipper axial tooth profile figure in the manufacturing sketch marked is to roll before the double replacement type mill.The nipper lip surface tooth proportions of cutter and the axial pitch in accompanying drawing four illustrated embodiments.
In accompanying drawing 4 illustrated embodiments, what the back tooth axial tooth profile figure in the manufacturing sketch marked is the back tooth lip surface tooth proportions of double replacement type pre-grinding hob.
In sketch shown in the accompanying drawing 5, lay special stress on nipper and back tooth position and the structural relation of double replacement type pre-grinding hob, the angle at nipper flute angle and land ditch angle, back.