CN210789529U - Gear hob with parallel axes - Google Patents
Gear hob with parallel axes Download PDFInfo
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- CN210789529U CN210789529U CN201921193674.2U CN201921193674U CN210789529U CN 210789529 U CN210789529 U CN 210789529U CN 201921193674 U CN201921193674 U CN 201921193674U CN 210789529 U CN210789529 U CN 210789529U
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Abstract
The utility model discloses a parallel axis gear hobbing cutter belongs to gear machining cutter technical field. The hob comprises two types of convex teeth and concave teeth, wherein the convex tooth hob is used for hobbing the gear with the concave teeth parallel to the axis, and the concave tooth hob is used for hobbing the gear with the convex teeth parallel to the axis. It is characterized in that the height of the hob teeth is small, and the normal tooth profile of the hob is an enveloping curve of an arc curve. The normal tooth profile of the basic rack corresponding to the hob is a circular arc, but the pitch line of the basic rack is positioned at the contact point and is not positioned near the center of a circle. The utility model provides a pair of be used for processing hobbing cutter of parallel axis gear specially, be convenient for make. When the parallel axis gear is processed and produced, the parallel axis gears with the same modulus and different tooth numbers can be processed by using one cutter, the types and the number of the cutters are reduced, and the cost is reduced, so that a foundation is provided for batch production of the parallel axis gears.
Description
Technical Field
The utility model relates to a gear machining cutter technical field especially relates to a parallel axis gear hobbing cutter.
Background
The parallel axis gear is a novel gear based on a space conjugate curve meshing theory, and has the advantages of less tooth number, high efficiency, no relative sliding, small comprehensive curvature radius at a contact point and the like. It can be used in the fields of food, packaging machinery, robot, etc. At present, for machining of parallel axis gears, formed cutters such as finger cutters and disc cutters are mainly used for machining. However, the use of a forming tool results in indexing errors and relatively inefficient machining.
Common gear manufacturing processes include gear milling, gear hobbing, gear shaping, gear shaving, gear shaping, gear grinding and the like. Wherein the hobbing process is most widely applied. The gear hobbing machine is high in production efficiency, high in machining precision and good in adaptability, and gears with the same modulus and pressure angle can be machined by adopting the same hobbing cutter. However, the existing gear hobs cannot machine parallel axis gears due to different tooth profiles. Therefore, the parallel axis gear hob needs to be designed, so that the production efficiency of the line gear is improved, and a foundation is provided for batch production of the parallel axis gears.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem that the current parallel axis gear machining means is single, production efficiency is lower relatively, the utility model provides a special hobbing cutter for parallel axis gear hobbing machine. The processing efficiency and the processing precision of the line gear are improved, and a foundation is provided for the batch production of the parallel axis gears.
The purpose of the utility model is realized through one of following technical scheme at least.
A gear hob with parallel axes comprises a base cylinder and a basic spiral surface which is spirally distributed on the base cylinder; hob teeth and chip flutes are distributed on the surface of the basic spiral at intervals, and a row of hob teeth corresponds to one chip flute; each hob cutter tooth comprises a front cutter face, a top edge rear cutter face, a side edge rear cutter face, a cutting edge and a top edge;
the basic helical surface is obtained by rotating the axial tooth profile or the end face tooth profile of the parallel axis gear hob along a helical line.
The parallel axis gear hob comprises a convex gear hob and a concave gear hob, wherein the convex gear hob is used for hobbing the concave gear parallel axis gear, and the concave gear hob is used for hobbing the convex gear parallel axis gear.
The end face tooth profile of the convex tooth hob of the parallel axis gear hob is two sections of convex curves which are mutually symmetrical, and the end face tooth profile of the concave tooth hob is two sections of concave curves which are mutually symmetrical. The tooth profile curves of the end faces of the parallel axis gear hob can be uniformly expressed as follows:
(sin(α0)+sin(t))
in the formula, t is a parameter, xd1Is the abscissa, y, of the tooth profile curve of the end face of a gear hob with parallel axesd1Is the ordinate of the profile curve of the end face of the gear hob with parallel axes, r is the radius of the circular arc of the basic tooth profile, β1For parallel axis gear hob helix angle, α0Is the nominal pressure angle of the basic rack, rjThe pitch circle radius of the parallel axis gear hob is shown, and the basic tooth profile is the normal tooth profile curve of the basic rack of the parallel axis gear hob when α0When the tooth profile curve of the end face of the gear hob with the parallel axis is more than 0, t epsilon (0, pi), the curve is a concave curve when α0And (4) less than 0, t epsilon (pi, 2 & ltpi), wherein the tooth profile curve of the end face of the parallel axis gear hob is a convex curve.
Compared with an involute gear hob with the same module, the parallel axis gear hob has the tooth height of 1/3-1/4 which is the tooth height of the involute gear hob. Because the parallel axis gear is a point contact gear, the contact ratio of the line gear cannot be increased by increasing the tooth height, but the bending strength of the tooth root of the line gear is weakened. Therefore, the tooth height of the parallel axis gear is only 1/3-1/4 of the tooth height of the involute gear hobbing cutter, and the tooth height of the hobbing cutter is also only 1/3-1/4 of the tooth height of the involute gear hobbing cutter.
The parallel axis gear hob can be used for machining parallel axis gears with the same modulus and different tooth numbers. The line gear processed by the parallel axis gear hob is a pure rolling gear. Since the line gear is a point contact gear, the contact points of the point contact gear are integrated into a spiral line on the tooth surface, and the spiral line is called as the contact line of the line gear. The contact lines on the line gear can be expressed as:
in the formula, x is the abscissa of the contact line, y is the ordinate of the contact line, z is the vertical coordinate of the contact line, m is the radius of the spiral line where the contact point is located, n is a spiral line pitch parameter, t is a parameter, ts is the initial angle of the contact point, and te is the ending angle of the contact line.
And two normal tooth-shaped curves on two sides of the parallel axis gear hob are mutually symmetrical. The normal tooth profile curve of the basic rack corresponding to the parallel axis gear hob is an arc, and the normal tooth profile curve of the basic rack is expressed as follows:
xf2＝e+r*cos(t)；
yf2＝r*sin(t)-r*sin(α0)；
in the formula, t is a parameter, xf2Is the abscissa, y, of the normal tooth profile curve of the basic rack of the parallel axis gear hobf2Is the ordinate of the normal tooth profile curve of the basic rack of the parallel axis gear hob, e is the offset distance, r is the circular arc radius of the basic tooth profile, the normal tooth profile curve of the basic rack is the basic tooth profile, α0Is the nominal pressure angle of the basic tooth profile.
The end face tooth profile curve of the basic rack of the parallel axis gear hob is positioned between the end face tooth profile of the imaginary rack corresponding to the concave-tooth parallel axis gear and the end face tooth profile of the imaginary rack corresponding to the convex-tooth parallel axis gear; the gears with different tooth numbers and parallel axes can be processed by the same milling cutter. The line gear processed by the parallel axis gear hob cutter can be exchanged with the parallel axis gear processed by the same line gear milling cutter.
Compared with the prior art, the beneficial effects of the utility model are embodied in:
1. compared with the prior art of processing the line gear, the utility model discloses there is not indexing motion at processing line gear in-process, therefore the machining precision is higher. And the machining process is continuous cutting, so that the machining efficiency is higher.
2. The line gear with the same modulus can be processed by adopting a line gear hob, so that the number of cutters is reduced, the management is convenient, and the production cost is favorably reduced.
3. The hobbing machining manufacturing process is simple, and the machining can be completed only by replacing the hobbing cutters with corresponding modules when the gears with different modules are machined.
4. The traditional gear hobbing machine can be adopted to process the line gear under the condition of not changing the structure of the traditional gear hobbing machine, the enterprise cost is not required to be additionally increased, and the popularization and the development of the line gear are facilitated.
Drawings
Fig. 1 is a schematic view of the hob structure of the present invention.
Fig. 2 is a normal tooth profile curve of the basic rack of the convex-toothed linear gear hob of the present invention.
Fig. 3 is a normal tooth profile curve of the basic rack of the concave-toothed linear gear hob of the present invention.
Fig. 4 is a schematic view of the meshing state of the basic worm of the convex arc gear hob and the basic rack.
FIG. 5 is a schematic view of the meshing state of the basic worm of the concave arc line gear hob and the basic rack.
FIG. 6 is a comparison of the imaginary rack face tooth profile curves for the convex and concave curve gears with the basic rack face tooth profile for the parallel axis gear hob.
FIG. 7 is the end face tooth profile curve of the rack corresponding to the gear with the concave teeth parallel axis and the gear with the convex teeth parallel axis with different pitch circle radii.
In the figure:
the hobbing cutter comprises a base cylinder 1, a basic spiral surface 2, hobbing cutter teeth 3, a chip groove 4, a rake face 5, a top edge rear face 6, a side edge rear face 7, a cutting edge 8, a top edge 9, a hobbing cutter axial tooth profile 10, an imaginary rack end face tooth profile 11 corresponding to a milling tooth convex arc gear end face tooth profile, a basic rack end face tooth profile 12, an imaginary rack end face tooth profile 13 corresponding to a milling tooth concave arc gear end face tooth profile, a large pitch radius convex tooth parallel axis gear imaginary rack end face tooth profile 14, a small pitch radius convex tooth parallel axis gear imaginary rack end face tooth profile 15, a large pitch radius concave tooth parallel axis gear imaginary rack end face tooth profile 16 and a small pitch radius convex tooth parallel axis gear imaginary rack end face tooth profile 17.
Detailed Description
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following description will be made with reference to the drawings in the embodiments of the present invention, and clearly and completely describe the technical solutions in the embodiments of the present invention, it is obvious that the described embodiments are only a part of the embodiments of the present invention, and all other embodiments obtained by a person having ordinary skill in the art without creative work should belong to the scope of the present invention.
Example (b):
as shown in fig. 1, the present embodiment is a thread gear hob, which includes a base cylinder 1 and a substantially helical surface 2 spirally disposed on the base cylinder 1; hob teeth 3 and chip flutes 4 are distributed on the basic spiral surface 2 at intervals, and a row of hob teeth corresponds to one chip flute; each hob tooth 3 comprises a rake face 5, a top edge flank face 6, a side edge flank face 7, a top edge 9 and a cutting edge 8. The basic helical surface 2 is obtained by rotating the axial tooth profile 10 or the end face tooth profile of a parallel axis gear hob along a helical line.
The parallel axis gear hob comprises a convex gear hob and a concave gear hob, wherein the convex gear hob is used for hobbing the concave gear parallel axis gear, and the concave gear hob is used for hobbing the convex gear parallel axis gear.
The end face tooth profile of the convex tooth hob is two sections of convex curves which are mutually symmetrical, and the end face tooth profile of the concave tooth hob is two sections of concave curves which are mutually symmetrical; the tooth profile curves of the end faces of the parallel axis gear hob can be uniformly expressed as follows:
(sin(α0)+sin(t))
in the formula, t is a parameter, xd1Is the abscissa, y, of the tooth profile curve of the end face of a gear hob with parallel axesd1Is the ordinate of the profile curve of the end face of the parallel axis gear hob, r is the circular arc radius of the basic tooth profile which is the normal profile curve of the basic rack of the parallel axis gear hob, β1For parallel axis gear hob helix angle, α0Is the nominal pressure angle of the basic tooth profile, rjIs the pitch radius of a gear hob with parallel axes when α0When the tooth profile curve of the end face of the gear hob with the parallel axis is more than 0, t epsilon (0, pi), the curve is a concave curve when α0And (4) less than 0, t epsilon (pi, 2 & ltpi), wherein the tooth profile curve of the end face of the parallel axis gear hob is a convex curve.
To achieve good root bending strength, the parallel axis gear hob tooth height is 1/3-1/4 of the involute gear hob tooth height. As shown in fig. 2 and 3, the normal tooth profile curve of the parallel axis gear hob may be obtained by enveloping the normal tooth profile curve of the basic rack of the parallel axis gear hob, two normal tooth profile curves at two sides of the parallel axis gear hob are symmetrical to each other, the normal tooth profile curve of the basic rack corresponding to the parallel axis gear hob is an arc, and the normal tooth profile curve of the basic rack of the parallel axis gear hob may be represented as:
xf2＝e+r*cos(t)；
yf2＝r*sin(t)-r*sin(α0)；
in the formula, t is a parameter, xf2Are parallel axesAbscissa, y, of normal tooth profile curve of basic rack of gear hobf2Is the ordinate of the normal tooth profile curve of the basic rack of the parallel axis gear hob, e is the offset distance, r is the circular arc radius of the basic tooth profile, the normal tooth profile curve of the basic rack is the basic tooth profile, α0Is the nominal pressure angle of the basic tooth profile.
In this embodiment, the parallel axis gear hob is in conjugate engagement with the primary rack as shown in fig. 4 and 5. The parallel axis gear hob comprises a convex gear hob and a concave gear hob, wherein the convex gear hob is used for hobbing the concave gear parallel axis gear, and the concave gear hob is used for hobbing the convex gear parallel axis gear.
The tooth profile curve of the end face of the basic rack of the parallel axis gear hob can be expressed as follows:
yd2＝r*sin(t)-r*sin(α0)；
in the formula, t is a parameter, xd2Is the abscissa, y, of the profile curve of the end face of the basic rack of the parallel-axis gear hobd2As ordinate of the profile curve of the end face of the basic rack of a parallel-axis gear hob, β2A parallel axis gear helix angle.
The parallel axis gear hob can be used for machining parallel axis gears with the same modulus and different tooth numbers. The line gear processed by the parallel axis gear hob is a pure rolling gear. Since the line gear is a point contact gear, the contact points of the point contact gear are integrated into a spiral line on the tooth surface, and the spiral line is called as the contact line of the line gear. The contact lines on the line gear can be expressed as:
in the formula, x is the abscissa of the contact line, y is the ordinate of the contact line, z is the vertical coordinate of the contact line, m is the radius of the spiral line where the contact point is located, n is a spiral line pitch parameter, t is a parameter, ts is the initial angle of the contact point, and te is the ending angle of the contact line. The left and right normal tooth-shaped curves of the parallel axis gear hob are mutually symmetrical.
As shown in fig. 6, the basic rack end face tooth profile curve 12 is located between an imaginary rack end face tooth profile curve 13 corresponding to the concave arc parallel axis gear end face tooth profile and an imaginary rack end face tooth profile curve 11 corresponding to the convex arc parallel axis gear end face tooth profile. Therefore, the cut parallel axis gear end face tooth profile is also positioned between the concave arc parallel axis gear end face tooth profile and the convex arc parallel axis gear end face tooth profile. Therefore, the tooth profile of the end face of the line gear obtained by hobbing of the parallel axis gear is similar to that of the end face of the parallel axis gear obtained by milling, and the two parts have interchangeability.
As shown in fig. 7, the imaginary rack end face tooth profile 14 of the large pitch radius parallel axis gear is located inside the imaginary rack end face tooth profile 15 of the small pitch radius parallel axis gear. The imaginary rack end face tooth form 16 of the large pitch circle radius concave tooth parallel axis gear is positioned outside the imaginary rack end face tooth form 17 of the small pitch circle radius concave tooth parallel axis gear. The bigger the pitch circle radius of the linear gear is, the more and more separated the tooth forms of the end faces of the racks corresponding to the concave tooth linear gear and the convex tooth linear gear of a pair of mutually meshed parallel shafts. Therefore, the designed parallel axis gear hob can always machine the parallel axis gear with the radius larger than the pitch circle radius of the selected pair of concave tooth and convex tooth line gears and can be interchanged with the parallel axis gear obtained by the gear milling machining.
The utility model discloses to the structural feature of line gear, provided a special processing hobbing cutter of parallel axis gear and parallel axis gear hobbing cutter design method, simplified parallel axis gear hobbing cutter design process greatly. The machining precision of the parallel axis gear is improved, and the machining efficiency of the parallel axis gear is improved. And a production foundation is laid for the mass production of the parallel axis gears. Is beneficial to the further popularization and application of the line gear.
Claims (6)
1. A parallel axis gear hob comprises two types of a convex gear hob and a concave gear hob, wherein the convex gear hob is used for hobbing of a concave gear parallel axis gear, and the concave gear hob is used for hobbing of a convex gear parallel axis gear, and is characterized in that the parallel axis gear hob comprises a base cylinder and a basic spiral surface which is spirally distributed on the base cylinder; the basic spiral surface is distributed with hob teeth and chip flutes at intervals, and a row of hob teeth corresponds to a chip flute in front of the hob teeth; each hob cutter tooth comprises a front cutter face, a top edge rear cutter face, a side edge rear cutter face, a cutting edge and a top edge;
the basic helical surface is obtained by rotating the axial tooth profile or the end face tooth profile of the parallel axis gear hob along a helical line.
2. The parallel axis gear hob of claim 1, characterized in that the tooth profile of the end face of the male gear hob is two convex curves that are symmetrical to each other, and the tooth profile of the end face of the female gear hob is two concave curves that are symmetrical to each other; the tooth profile curves of the end faces of the parallel axis gear hob can be uniformly expressed as follows:
(sin(α0)+sin(t))
in the formula, t is a parameter, xd1Is the abscissa, y, of the tooth profile curve of the end face of a gear hob with parallel axesd1Is the ordinate of the profile curve of the end face of the parallel axis gear hob, r is the circular arc radius of the basic tooth profile which is the normal profile curve of the basic rack of the parallel axis gear hob, β1For parallel axis gear hob helix angle, α0Is the nominal pressure angle of the basic tooth profile, rjIs parallel toPitch radius of axial gear hob when α0When the tooth profile curve of the end face of the gear hob with the parallel axis is more than 0, t epsilon (0, pi), the curve is a concave curve when α0And (4) less than 0, t epsilon (pi, 2 & ltpi), wherein the tooth profile curve of the end face of the parallel axis gear hob is a convex curve.
3. The parallel axis gear hob of claim 1, wherein: compared with an involute gear hob with the same module, the tooth height of the parallel axis gear hob is 1/3-1/4 of the tooth height of the involute gear hob.
4. The parallel axis gear hob according to claim 1, characterized in that a pair of parallel axis gear hobs can be used for processing parallel axis gears with the same module and different numbers of teeth; the line gear processed by the parallel axis gear hob is a pure rolling gear; because the line gear is a point contact gear, the contact point of the point contact gear is integrated on the tooth surface to form a spiral line, and the spiral line is called as a contact line of the line gear; the contact lines on the line gear can be expressed as:
in the formula, x is the abscissa of the contact line, y is the ordinate of the contact line, z is the vertical coordinate of the contact line, m is the radius of the spiral line where the contact point is located, n is a spiral line pitch parameter, t is a parameter, ts is the initial angle of the contact point, and te is the ending angle of the contact line.
5. The parallel axis gear hob of claim 2, characterized in that the normal tooth profiles of the two basic racks on both sides of the parallel axis gear hob are symmetrical to each other; the normal tooth profile curve of the basic rack corresponding to the parallel axis gear hob is an arc, and the normal tooth profile curve of the basic rack of the parallel axis gear hob can be expressed as follows:
xf2＝e+r*cos(t)；
yf2＝r*sin(t)-r*sin(α0)；
in the formula, xf2Is the abscissa, y, of the normal tooth profile curve of the basic rack of the parallel axis gear hobf2Is the ordinate of the normal tooth profile curve of the basic rack of the parallel axis gear hob, e is the offset distance, r is the circular arc radius of the basic tooth profile, α0Is the nominal pressure angle of the basic tooth profile.
6. The parallel axis gear hob of claim 1, wherein: the end face tooth profile curve of the basic rack of the parallel axis gear hob is positioned between the end face tooth profile of the imaginary rack corresponding to the concave-tooth parallel axis gear and the end face tooth profile of the imaginary rack corresponding to the convex-tooth parallel axis gear; the gears with different tooth numbers and parallel axes can be processed by the same milling cutter; the parallel axis gear obtained by the hobbing cutter of the parallel axis gear can be interchanged with the parallel axis gear obtained by the milling cutter of the same linear gear.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921193674.2U CN210789529U (en) | 2019-07-26 | 2019-07-26 | Gear hob with parallel axes |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921193674.2U CN210789529U (en) | 2019-07-26 | 2019-07-26 | Gear hob with parallel axes |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110434409A (en) * | 2019-07-26 | 2019-11-12 | 华南理工大学 | One kind parallels to the axis gear hob and its design method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110434409A (en) * | 2019-07-26 | 2019-11-12 | 华南理工大学 | One kind parallels to the axis gear hob and its design method |
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