Arc-surface milling cutter assembly for eliminating tooth crest interference of worm gear and machining device of arc-surface milling cutter assembly

Abstract

The utility model provides an arc surface milling cutter combination for eliminating worm gear tooth crest interference and a processing device thereof, which comprise an arc surface milling cutter body, taper shanks are arranged at two ends of the arc surface milling cutter body, a support end connecting sleeve is arranged on the taper shank at one end, and a main shaft connecting sleeve is arranged on the taper shank at the other end. Due to the fact that systematic planning is conducted when the connecting sleeves are designed at the two ends of the cutter body, it is guaranteed that when worm gears of different specifications and sizes are milled on the same machine tool, only the arc face milling cutter needs to be replaced, the two connecting sleeves do not need to be replaced, and the cutter body does not need to be corrected many times in the installation and positioning aspect; interference between a worm gear addendum circle and a worm root circle during meshing of a small-modulus high-precision worm gear pair is eliminated, meshing precision of the worm gear and the worm is guaranteed, concentricity of a worm gear addendum arc surface and a tooth part degree circle is guaranteed, the middle section of the worm gear addendum arc surface and the middle section of a tooth part are located in the same plane, precision of the arc surfaces is improved, and the service life of the worm gear and the worm gear is prolonged. And the method can also be used for checking the worm gear tooth assembly reference.

Description

Technical Field

[0001] This utility model relates to the field of worm gear hobbing technology, and in particular to a combination of arc-shaped milling cutters and its processing device for eliminating interference at the tooth tips of worm gears. Background Technology

[0002] High-precision machine tools often use small-module worm gears. The tip arc surface of the worm gear teeth is machined on a lathe. The worm gear ring and worm gear housing are assembled together with a clearance fit, and screws are used to fasten them together. Because the worm gear housing and worm gear ring have their own dimensional and form errors when machined separately, there are eccentricity errors and axial dimensional errors when they are assembled together with a clearance fit. In addition, because the worm gear pair involved in the example has a small module, the tip clearance of the worm gear pair meshing is small.

[0003] All these factors combined make interference between the worm gear tip arc surface and the worm gear root circle highly probable during worm gear meshing. The hobbing datum and assembly datum of the worm gear assembly are both on the worm gear housing. This datum is obscured after the outer parts of the machine tool are assembled and cannot be inspected. However, the worm gear tip arc surface can be inspected using a dial indicator through the oil window. If there is eccentricity between the worm gear ring and the worm gear housing during assembly due to clearance fit, the arc surface cannot be used as a datum for checking concentricity, affecting the overall machining accuracy of the worm gear teeth and thus reducing the product yield. Utility Model Content

[0004] To address the aforementioned defects and shortcomings, the present invention aims to provide a circular arc milling cutter assembly and its machining device for eliminating interference at the worm gear tooth tip. During the precision hobbing of the worm gear assembly, the circular arc surface at the worm gear tooth tip is precision milled to ensure that the circular arc surface at the worm gear tooth tip is concentric with the assembly datum on the worm gear seat, while ensuring the accuracy of the circular arc surface dimensions. During worm gear meshing, the worm axis is ensured to be within the mid-section of the circular arc surface at the worm gear tooth tip.

[0005] The technical solution of this utility model is as follows:

[0006] An arc-shaped end mill for eliminating interference at the tip of a worm gear includes: an arc-shaped end mill body, with tapered shanks at both ends of the arc-shaped end mill body, a support end connecting sleeve mounted on one tapered shank, and a spindle connecting sleeve mounted on the other tapered shank.

[0007] The taper of the tapered shanks at both ends of the arc-shaped milling cutter body is 1:20.

[0008] The tapered outer circle of the taper handle engages with the tapered hole of the support end connecting sleeve.

[0009] The tapered outer circle of the taper shank engages with the tapered hole on the connecting sleeve at the spindle end.

[0010] The arc-shaped milling cutter body and the spindle end connecting sleeve are fixed by wedges.

[0011] The radius of the arc-shaped milling cutter body is the same as the radius of the arc surface at the tip of the worm gear tooth to be machined.

[0012] A machining apparatus for eliminating interference at the tip of worm gear teeth includes: a gear hobbing machine, on which the aforementioned arc-shaped milling cutter assembly for eliminating interference at the tip of worm gear teeth is mounted; a machine tool table is provided on one side of the gear hobbing machine; a horizontally arranged gear hobbing seat is mounted on the machine tool table; a horizontally arranged worm gear seat is mounted on the gear hobbing seat; and a worm gear to be machined is fixedly mounted on the worm gear seat; the worm gear to be machined is in contact with the arc-shaped milling cutter assembly.

[0013] The outer tapered surface of the spindle end connecting sleeve is connected to the spindle tapered hole of the gear hobbing machine.

[0014] The outer conical surface of the support end connecting sleeve is connected to the support end of the gear hobbing machine.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] This utility model provides a circular arc surface milling cutter assembly for eliminating interference between worm gear tooth tips. Due to the systematic planning of the connecting sleeves at both ends of the cutter body, when milling worm gears of different specifications and sizes on the same machine tool, only the circular arc surface milling cutter needs to be replaced, and the two connecting sleeves do not need to be replaced. This eliminates the need for multiple calibrations in terms of cutter body installation and positioning, effectively eliminating the interference between the worm gear tooth tip circle and the worm tooth root circle during the meshing of small module high-precision worm gear pairs, and ensuring the meshing accuracy of the worm gear and worm.

[0017] In addition, this utility model also provides a machining device for eliminating interference at the tip of worm gear teeth. After precision milling the tip arc surface of the worm gear with a circular arc milling cutter before precision hobbing, the dimensional and positional errors of the tip arc surface of the worm gear teeth are corrected, eliminating the interference between the tip arc surface of the worm gear teeth and the root circle of the worm gear teeth during worm gear meshing. This ensures the concentricity of the tip arc surface of the worm gear teeth and the worm gear teeth, so that the tip arc surface of the worm gear teeth can be used as a reference to check whether the worm gear is concentric with the assembly reference on the machine tool after the worm gear is assembled in the machine tool. Attached Figure Description

[0018] Figure 1 This is a sectional view of the circular arc milling cutter assembly of this utility model;

[0019] Figure 2 This is a three-dimensional structural diagram of the circular arc milling cutter assembly of this utility model;

[0020] Figure 3 This is a cross-sectional view of the machining device for eliminating interference at the tip of worm gear teeth, as described in this utility model.

[0021] In the figure, 1—support end connecting sleeve; 2—arc milling cutter body; 3—wedge; 4—spindle end connecting sleeve; 5—gear hobbing seat; 6—worm gear seat; 7—worm gear tooth to be machined; 8—machine tool table; 9—arc milling cutter assembly. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings. The described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] like Figure 1 , 2 As shown, this utility model provides an arc-shaped milling cutter assembly for eliminating interference at the tip of worm gear teeth, comprising: an arc-shaped milling cutter body 2, wherein tapered shanks 21 are provided at both ends of the arc-shaped milling cutter body 2, a support end connecting sleeve 1 is installed on one end of the tapered shank 21, and a spindle connecting sleeve 4 is installed on the other end of the tapered shank 21.

[0024] Since worm gears are generally made of tin bronze, the cutting edge of the arc-shaped milling cutter can be made of ordinary tool steel, such as Wo6Mo5Cr4V2.

[0025] The radius of the arc-shaped milling cutter body 2 is the same as the radius of the arc surface at the top of the worm gear tooth 7. In the example, the radius of the arc surface is R17, and the diameter of the designed arc-shaped milling cutter is Φ34±0.05.

[0026] Preferably, the taper of the tapered shanks 21 at both ends of the arc-shaped milling cutter body 2 is 1:20, that is, the two ends of the milling cutter have a 1:20 tapered outer circle, which is used to connect with the support end connecting sleeve 1 and the spindle connecting sleeve 4 respectively.

[0027] Specifically, one end of the spindle end connecting sleeve 4 is provided with a 1:20 tapered hole, which engages with the tapered outer circle of the tapered shank 21 to connect to the arc-shaped milling cutter. The other end of the spindle end connecting sleeve 4 is provided with a 7:24 tapered outer circle, which is connected to the tapered hole of the gear hobbing machine spindle.

[0028] The spindle end connecting sleeve 4 is provided with a waist-shaped groove, and a wedge 3 is installed in the waist-shaped groove. The wedge 3 passes through the arc-shaped milling cutter body 2 and is fixed in the waist-shaped groove to prevent the spindle end connecting sleeve 4 from separating from the arc-shaped milling cutter body 2.

[0029] One end of the support end connecting sleeve 1 is provided with a 1:20 tapered hole, and the tapered outer circle of the tapered shank 21 engages with the tapered hole of the support end connecting sleeve 1. One end of the support end connecting sleeve 1 is provided with a 7:24 outer tapered surface, which connects with the support end support sleeve of the gear hobbing machine. The outer tapered diameter and dimensions on both connecting sleeves are related to the gear hobbing machine used.

[0030] like Figure 3As shown, this utility model also provides a machining device for eliminating interference at the tip of worm gear teeth, comprising: a gear hobbing machine, on which the above-mentioned arc-shaped milling cutter assembly 9 for eliminating interference at the tip of worm gear teeth is mounted, a machine tool table 8 is provided on one side of the gear hobbing machine, a horizontally arranged gear hobbing seat 5 is mounted on the machine tool table 8, a horizontally arranged turbine seat 6 is mounted on the gear hobbing seat 5, and the worm gear teeth 7 to be machined are fixedly mounted on the turbine seat 6; the worm gear teeth 7 to be machined are in contact with the arc-shaped milling cutter assembly 9.

[0031] Figure 3 In the hobbing process, A represents the center distance of the worm gear (the distance between the center of the hob and the center of the worm gear), and H represents the center height of the worm gear (the distance between the reference surface on the worm gear and the mid-section of the worm gear teeth). These two parameters are key parameters for finish milling the arc surface of the worm gear. During rough machining of the arc surface of the worm gear teeth, an appropriate allowance is left for finish milling. Before the finish hobbing process, the center distance A and center height H of the hobbing machine are adjusted (obtained from the technical data of the worm gear to be machined), and then... Figure 1 As shown, install the arc milling cutter and connecting sleeve, and after installing the worm gear assembly, mill the arc surface of the worm gear tooth tip along the radial direction of the worm gear. The cutter should be inserted to the center distance A. At this point, the arc surface of the worm gear tooth tip has been finished by precision milling.

[0032] The working process of this utility model is as follows:

[0033] During machining, a gear hobbing holder 5 is horizontally mounted on the machine tool table 8, and the runout of the upper positioning surface of the gear hobbing holder 5 is checked to be ≤0.005mm. A measuring rod with diameter D is installed in the machine tool spindle taper hole. A gauge block is placed on the upper surface of the gear hobbing holder 5, with a height h = center height A + measuring rod diameter D / 2. At this time, the gear hobbing machine tool holder is moved up and down, and a lever micrometer is used to measure that the upper working surface of the gauge block placed on the gear hobbing holder 5 is in the same plane as the generatrix on the measuring rod. The coplanarity error required in this example is ±0.015mm. At this time, the center height H of the worm gear tooth 7 to be machined in this example has been adjusted to the correct position.

[0034] Remove the measuring rod and install it on the gear hobbing machine spindle. Figure 2 The arc-shaped milling cutter assembly 9 shown has a gear hobbing machine support mounted on the outer cone of the support end connecting sleeve.

[0035] Mount the worm gear seat 6 and the worm gear tooth 7 to be machined onto the hobbing seat 5, and correct the runout of the reference circular surface on the worm gear seat 6 to ≤0.005mm. Then fasten the worm gear seat 6 and the hobbing seat 5 together with bolts.

[0036] Using radial feed, bring the arc-shaped milling cutter assembly 9 into contact with the worm gear tooth 7 to be machined, and continue radial feed until the center distance A of the worm gear tooth 7 is reached. The top arc surface of the worm gear tooth 7 is then finished by precision milling.

[0037] Because a systematic plan was made when designing the arc milling cutter and connecting sleeve, when finishing arc surfaces of different radii, if the specifications of the gear hobbing machine remain unchanged, only the arc milling cutter of the corresponding radius needs to be replaced, and the connecting sleeves at both ends do not need to be replaced. The above processing procedure can be repeated during milling.

Claims

1. A circular arc milling cutter assembly for eliminating interference at the worm gear tooth tip, characterized in that, include: A circular arc milling cutter body (2) is provided with tapered shanks (21) at both ends. A support end connecting sleeve (1) is installed on one end of the tapered shank (21), and a spindle connecting sleeve (4) is installed on the other end of the tapered shank (21).

2. The arc-shaped milling cutter assembly for eliminating worm gear tooth tip interference according to claim 1, characterized in that, The taper of the tapered shanks (21) at both ends of the arc-shaped milling cutter body (2) is 1:

20.

3. The arc-shaped milling cutter assembly for eliminating interference at the worm gear tooth tip according to claim 2, characterized in that, The tapered outer circle of the taper shank (21) engages with the tapered hole of the support end connecting sleeve (1).

4. The arc-shaped milling cutter assembly for eliminating worm gear tooth tip interference according to claim 2 or 3, characterized in that, The tapered outer circle of the taper shank (21) engages with the tapered hole on the main shaft end connecting sleeve (4).

5. The arc-shaped milling cutter assembly for eliminating worm gear tooth tip interference according to claim 2 or 3, characterized in that, The arc-shaped milling cutter body (2) and the spindle end connecting sleeve (4) are fixed by wedges (3).

6. The arc-shaped milling cutter assembly for eliminating worm gear tooth tip interference according to claim 1, characterized in that, The radius of the arc-shaped milling cutter body (2) is the same as the radius of the top arc surface of the worm gear tooth (7) to be machined.

7. A machining apparatus for eliminating interference at the tip of worm gear teeth, characterized in that, include: A gear hobbing machine is equipped with an arc-shaped milling cutter assembly (9) for eliminating interference at the tip of worm gear teeth as described in any one of claims 1-6. A machine tool table (8) is provided on one side of the gear hobbing machine. A horizontally arranged gear hobbing seat (5) is installed on the machine tool table (8). A horizontally arranged turbine seat (6) is installed on the gear hobbing seat (5). The worm gear teeth (7) to be processed are fixedly installed on the turbine seat (6). The worm gear teeth (7) to be processed are in contact with the arc-shaped milling cutter assembly (9).

8. The machining apparatus for eliminating interference at the tip of worm gear teeth according to claim 7, characterized in that, The outer conical surface of the spindle end connecting sleeve (4) is connected to the spindle conical hole of the gear hobbing machine.

9. The machining apparatus for eliminating interference at the tip of worm gear teeth according to claim 7 or 8, characterized in that, The outer conical surface of the support end connecting sleeve (1) is connected to the support end of the gear hobbing machine.

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