CN100525976C - Hob complete utilization integrated gear hobbing method - Google Patents

Abstract

A comprehensive gear hobbing method that fully utilizes the hob. Before hobbing, the relative position of the hob and the workpiece is calculated according to the parameters of the processed gear and the hob. Distance h, take the intersection point of the hob end face and the hob outer diameter generatrix to the axis center of the workpiece as the entry point for radial incomplete hobbing, angular full tooth hobbing, angular hobbing full tooth width or axial hobbing Full tooth width machining. Concentrate and optimize the advantages of the original axial, radial and angular hobbing methods to overcome its shortcomings, and solve the problems of axial hobbing due to the increase in the outer diameter of the hob, the lengthening of the air cutting distance, and the decline in production efficiency. The incomplete teeth are fully and fully utilized, which improves the production efficiency and the service life of the hob, makes the hob wear evenly, and reduces the production cost. , provides a feasible processing technology, this method can be easily implemented on the CNC gear hobbing machine.

Description

Integrated gear hobbing method for full utilization of the hob

technical field

The invention relates to a method of using all the teeth on the hob to process gears, in particular to a comprehensive gear hobbing method which fully utilizes the incomplete teeth at both ends of the hob.

Background technique

Gear hobbing is the most widely used gear processing technology at present. The hob is the most important process equipment to realize gear hobbing. Because the teeth at both ends of the hob are incomplete, it cannot envelop a complete and effective tooth shape, so It has not been used in the past processing technology. This has been included in the textbook. The textbook emphasizes that only the complete and effective L1 part of the total length L of the hob can be used, and the incomplete L0 part should be completely avoided to avoid damage to the processed gear. The tooth shape error and the product are scrapped, as shown in Figure 1 and Figure 2. 3 in Fig. 2 is the incomplete tooth on both ends of hob 1.

The axial hobbing method is generally used in gear hobbing, followed by radial and angular hobbing methods:

The processing method in which the hob 1 feeds in the direction indicated by the axial direction f of the workpiece 4 to be processed is called axial hobbing. As shown in Figure 3, the hob 1 needs to move a distance from contacting the workpiece 4 to cutting out the complete tooth shape It is called the air-cutting distance a, if the hob 1′ outer diameter d′>hob 1 outer diameter d, then the air-cutting distance a′>a, when the high-efficiency and high-precision large outer diameter hob 1′ is used as the axial When hobbing, it takes a long time compared to the hob 1 with a small diameter, so the production efficiency is low, that is, this processing method is directly related to the diameter of the hob, and it is not suitable for processing with a hob with a large outer diameter. Such as spur gear: $a=\sqrt{h\·(d-h)}$ $a\′=\sqrt{h\&Center\; Dot;(d\′-h)}$

The processing method in which the hob 1 feeds in the direction shown by the radial direction fr of the workpiece 4 to be processed is called radial hobbing, as shown in Figure 4, although there is no problem of empty cutting distance, it can be said to be the most efficient method. However, this method cannot cut out the full tooth width, and from the beginning of cutting to the full tooth depth, the cutting resistance will increase exponentially, which is unfavorable for the control of the feeding process and the control of the product precision, and has great limitations. , when used alone, it can only be used to process worm gear products with low requirements.

The hob 1 not only feeds in the direction shown by the axial direction f of the workpiece 4, but also feeds in the direction shown by the axial direction f ₁ of the hob, which is called angular hobbing, as shown in Figure 5II. The hob wears evenly, the surface quality of the cutting gear is good, and the stability and precision of the gear transmission are improved. However, this method increases the axial movement of the hob, which increases the complexity of the equipment and the difficulty of process adjustment. Tooth direction error increases, affected by the above factors, this more advanced gear hobbing method has not been popularized.

Each of the above-mentioned processing methods has its own advantages and disadvantages, but because the incomplete teeth at both ends of the hob have not been utilized, the utilization rate of the hob is low and the service life is short, resulting in waste of resources and increase in production costs.

Contents of the invention

The technical problem to be solved by the present invention is: to provide a comprehensive gear hobbing method that fully utilizes the hob, and the incomplete teeth at both ends of the hob that have not been used in the past hobbing process can be completely and fully processed by this method. When used, the efficiency and quality of hobbing processing are improved, and the service life and hobbing accuracy of the hob are improved, so that all the teeth are worn evenly and the waste of materials is reduced.

The technical solution adopted by the present invention to solve the above problems is: the comprehensive gear hobbing method that the hob fully utilizes,

Method steps: 1, radial incomplete tooth hobbing:

Before hobbing, calculate and adjust the relative position of hob 1 and workpiece 4 according to the parameters of the workpiece and hob. It is necessary to keep a certain distance h between the intersection point of the center line of the hob axis and the end surface of the hob and the end plane of the workpiece.

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="f\; f"\; filenames="C200710071364E00084.png,C200710071364E00085.png"\; state="\{\{state\}\}">f</figure-callout></span><figure-callout\; id="1"\; label="f\; f"\; filenames="C200710071364E00084.png,C200710071364E00085.png"\; state="\{\{state\}\}">\; </figure-callout>}}{{\mathrm{<span\; class="notranslate">\; </span>}}_{}}$

K is the safety factor, K × m _n is the safety distance, m _n × π is the complete tooth pitch of the gear, m _n is the normal modulus, f, f ₁ is the axial and tangential feed,

The intersection of one end plane of the hob 1 and the generatrix of the outer diameter of the hob is aligned with the axis center of the workpiece 4 as the cutting point, and the workpiece 4 is radially fed to the full tooth depth in the f _r direction;

II. Angular full gear hobbing:

Immediately after the deep processing of the above-mentioned full teeth, the angular hobbing is carried out again. The hob 1 is fed in the direction of the axial f and the tangential f _1. When the hob is effective and the meshing of the complete teeth is generated, the center 5 is flush with the upper end surface of the workpiece , cut out the complete tooth shape;

III. Full tooth width of angular hobbing:

Immediately after the complete tooth shape is cut out above, the angular hobbing is carried out, and the hob is fed in the direction of axial f and tangential f ₁ until the full tooth width is cut;

III', axial hobbing full tooth width:

Immediately after the complete tooth shape is cut out above, the angular hobbing is changed to axial hobbing, and the hob is fed in the axial f direction until the full tooth width is cut;

IV. When the incomplete tooth 3 at one end of the hob 1 has been used for a period of time, the hob can be turned around and installed, and processed according to steps I, II, III or III' by changing the direction of rotation or milling of the hob. At this time Still use h in step I, no need to calculate.

Compared with the prior art, the advantage of the present invention is that: compared with the single hobbing method in which hobs cannot be fully utilized in the past, this comprehensive method concentrates and optimizes the advantages of the original various hobbing methods, and overcomes its disadvantages. insufficient. If it effectively solves the problem that the axial hobbing distance increases with the increase of the outer diameter of the hob and the production efficiency decreases, the lifting distance h has nothing to do with the outer diameter of the hob. This comprehensive method ignores the axial hobbing. The air cutting distance a required for the initial section of hobbing provides a perfect processing technology for the use of hobs with large outer diameter, high efficiency, high precision, and no regrinding. This comprehensive method realizes the complete utilization of the hob, improves the service life of the hob, makes the wear of the hob uniform, overcomes the tooth shape error caused by uneven wear of the cutter teeth, and improves the stability and precision of the gear work. In addition, the original gear hobbing process lacks a clear reference for tool setting, so it is difficult to find the complete tooth meshing center of the hob, that is, the entry point. The central part of the knife, so the wear of the hob is uneven, and the utilization rate of the hob is low. Now it is clear that the intersection point between the end face of the hob and the busbar of the outer diameter of the hob is the entry point. The reference point is clear and easy to operate. Hobbing and cutting helical gears can also accurately align the center of the workpiece.

Description of drawings

Figure 1. Schematic diagram of the structure of the hob.

Figure 2, the left view of Figure 1.

Figure 3. Schematic diagram of axial hobbing.

Figure 4. Schematic diagram of radial hobbing.

Fig. 5. Schematic diagrams of related calculations in the present invention: I, schematic diagrams of h, II, schematic diagrams of meshing generation center.

Fig. 6. Schematic diagram of the steps of the gear hobbing method of the present invention: I, radial hobbing of incomplete teeth, II, angular hobbing of complete teeth, III, angular hobbing of full tooth width, III', axial hobbing of full tooth width .

Detailed ways

Embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Although the incomplete tooth 3 cannot be finally developed into a complete tooth shape of the enveloping gear, it is very beneficial for the rough cutting of the tooth groove, because the part of the incomplete tooth 3 is not only very sharp, but also the tooth height increases in the hob end section The Archimedes spiral 2 shown in Figure 2 is shown on the surface, so that the cutter teeth are gradually cut deeper during hobbing, and the load distribution of the cutter teeth is even. The incomplete tooth 3 at the end is fully competent and can be utilized.

Method steps: 1, radial incomplete hobbing:

Before hobbing, calculate and adjust the relative position of hob 1 and workpiece 4 according to the parameters of the workpiece gear and hob. It is necessary to keep a certain distance h between the center line of the hob axis and the end surface of the hob and the end plane of the workpiece, as shown in the figure As shown in 5I, when the lifting height h of the hob meets the requirements of angular hobbing, when the meshing generation center 5 of the effective and complete tooth part of the hob is flush with the end surface of the workpiece 4, effective and complete gear teeth can be enveloped , as shown in Figure 5II.

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\frac{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="f\; f"\; filenames="C200710071364E00084.png,C200710071364E00085.png"\; state="\{\{state\}\}">f</figure-callout></span><figure-callout\; id="1"\; label="f\; f"\; filenames="C200710071364E00084.png,C200710071364E00085.png"\; state="\{\{state\}\}">\; </figure-callout>}}{{\mathrm{<span\; class="notranslate">\; </span>}}_{}}$

K × m _n is the safety distance, K is the safety factor, m _n × π is the complete tooth pitch of the gear, m _n is the normal modulus, f, f ₁ is the axial and tangential feed, h and the hob The outer diameter is irrelevant, mainly related to the processing gear parameters and the ratio of angular feed;

The intersection point of the incomplete tooth 3 on one end plane of the hob 1 and the generatrix of the outer diameter of the hob is aligned with the axis center of the workpiece as the cutting point. As shown in Figure 6I, the workpiece 4 is radially fed to the full tooth in the direction f _r Deep, because the center of the hob is higher than the upper end surface of the workpiece, the cut tooth shape is incomplete. At this time, although the incomplete tooth 3 of the hob 1 is used to participate in the cutting, the initial processing has no effect on the tooth shape. On the contrary, the diameter can be increased. Even if the tooth is worn, it will not affect the tooth profile, and the hobbing time is $T_I=\frac{\mathrm{zg}}{\mathrm{no}{f}_r{z}_0},$

II. Angular full gear hobbing:

Immediately after the deep machining of the above-mentioned full teeth, the angular hobbing is carried out. As shown in Fig. 6II, the hob 1 is fed in the direction of axial f and tangential f ₁ . When it is flush with the upper end surface of the workpiece, the complete tooth shape is cut out, and the hobbing time is T _II ;

III. Full tooth width of angular hobbing:

Immediately after the complete tooth shape is cut out above, the angular hobbing is carried out, as shown in Figure 6III, the hob is fed in the direction of axial f and tangential f ₁ until the full tooth width is cut, and the workpiece 4 is processed into , the gear processed by the above steps is the best, and the hobbing time is T _III

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; II</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; III</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; nf</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

However, in actual production, it is limited by the length of the hob, the axial movement distance of the hob and the tooth width of the workpiece. If the above-mentioned angular hobbing cannot be used to cut the complete tooth, after the processing in Figure 6II is completed, From angular hobbing to axial hobbing;

III', axial hobbing full tooth width:

Immediately after the complete tooth shape is cut out above, the angular hobbing is changed to axial hobbing, and the hob is fed in the axial f direction until the full tooth width is cut, as shown in Figure 6III′, the hobbing time is T _III′ ,

${\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; II</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; III</span>}<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; nf</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

IV. When the incomplete tooth 3 at one end of the hob 1 has been used for a period of time, the hob can be turned around and installed, and processed according to steps I, II, III or III' by changing the direction of rotation or milling of the hob. At this time Still use h in the step I, no need to calculate again, just can reach the purpose of fully utilizing the incomplete teeth at both ends of the hob.

On an ordinary gear hobbing machine, as long as it has a tangential tool holder, this comprehensive method can be used to process gears.

The CNC gear hobbing machine has the functions of axial, radial and tangential processing. With the popularization and application of the CNC gear hobbing machine, it is possible to use the CNC gear hobbing machine to make the comprehensive gear hobbing method that the hob fully utilizes.

Example

Process a spur gear with normal modulus m _n =2mm, number of teeth Z=20, tooth width b=30mm, depth of cut g=4.5.

Hob outer diameter d=100mm, number of hob heads Z ₀ =1

Processing technology: hob speed n=400 rpm safety factor k=0.2

Axial feed f=0.66 mm/rev

Tangential feed f ₁ =0.22 mm/rev

Radial feed f _r = 1.2mm/rev

Reel Elevation:

Hobbing time: T = T _I + T _{II + III (or III')}

$<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; zg</span>}}{{\mathrm{<span\; class="notranslate">\; nf</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; b</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; nf</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 4.5</span>}}{\mathrm{<span\; class="notranslate">\; 400</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1.2</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 20</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10.62</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 30</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 400</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 0.66</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 1</span>}}$

Claims (1)

1, the comprehensive hobbing method that utilizes fully of a kind of hobboing cutter is characterized in that method step: I, radially imperfect tooth rolling cut:

Before the rolling cut, the calculation of parameter of pressing workpiece and hobboing cutter is adjusted the relative position of hobboing cutter (1) and workpiece (4), need the intersection point and the work end plane of cutter shaft center and hobboing cutter end face are maintained a certain distance h,

$h=(\frac{m_n\&times;\mathrm{\&pi;}}{2}+k\&times;m_n)\&times;\frac{f}{f_1}$

K is a safety coefficient, K * m _nBe safe distance, m _n* π is gear one a complete tooth pitch, m _nBe normal module, f, f ₁For axially reaching the tangential admission amount;

Imperfect tooth (3) on the transverse plane of hobboing cutter (1) is made point of penetration with the axis centre of the intersection point alignment pieces (4) of hobboing cutter external diameter bus, and workpiece (4) court is f radially _rThe direction radial feed is dark to full-depth tooth;

II, the complete tooth rolling cut of angle:

After being right after above-mentioned full-depth tooth deep processing, carry out the angle gear hobbing again, hobboing cutter (1) is by axially and the tangential direction feeding, when effective, the complete tooth of hobboing cutter meshes generate center (5) and workpiece (4) when the upper surface is concordant, cuts out complete profile of tooth;

Be right after above-mentioned cut out complete profile of tooth after, next procedure adopts the processing method of III or III ' to cut out widths over teeth;

III, angle rolling cut widths over teeth:

Be right after above-mentioned cut out complete profile of tooth after, carry out the angle gear hobbing again, hobboing cutter is by axially and the tangential direction feeding, until cutting out widths over teeth;

III ', axial rolling cut widths over teeth:

Be right after above-mentioned cut out complete profile of tooth after, become axial gear hobbing by the angle gear hobbing, hobboing cutter is pressed the axial direction feeding, until cutting out widths over teeth;

IV, when the imperfect tooth (3) of hobboing cutter (1) one end after using after a while, the hobboing cutter tune is installed, press I, II, the processing of III step again by the direction of rotation or the milling direction that change hobboing cutter, or press the poly-processing of I, II, III ' step, at this moment directly adopt the h among the step I, need not calculate again.

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