A method for grinding a gear or a gear-like profile using a grinding worm and a dressing tool

Abstract

This invention relates to a method for grinding gears or gear-shaped profiles using a multi-head grinding worm, wherein the grinding worm is dressed prior to grinding. During dressing the grinding worm, a dressing tool (1) is engaged with the grinding worm. The dressing tool (1) is configured as a multi-groove dressing roller having multiple dressing surfaces (2, 3, 4) extending around a dressing roller axis (a), the dressing surfaces being toothed in radial section. To make this method applicable to the economical and high-precision manufacture of gears with unequal tooth pitch profiles, the invention specifies that at least three dressing surfaces (2, 3, 4) are arranged at uneven intervals along the dressing roller axis (a), and / or at least two dressing surfaces (2, 3, 4) have different shapes in radial section. Furthermore, the invention also relates to a dressing tool.

Description

Technical Field

[0001] This invention relates to a method for grinding gears or gear-shaped profiles using a multi-head grinding worm, wherein the grinding worm is dressed prior to grinding. During dressing the grinding worm, a dressing tool is engaged with the grinding worm. The dressing tool is designed as a multi-groove dressing roller having multiple dressing surfaces extending around its axis, these dressing surfaces being toothed in radial cross-section. Furthermore, this invention also relates to a dressing tool. Background Technology

[0002] This known process enables the rapid, economical, and precise manufacture of gears.

[0003] Grinding using grinding worms is known in the prior art, see, for example, DE 10 2019 004687 A1, DE 10 2004 020 947 A1 and DE 10 2016 010 893 A1.

[0004] Gears inevitably generate noise during operation. High-quality hard finishing can reduce this noise, but it cannot completely eliminate it. Regular noise (noise with distinct tonal characteristics) is generally more unpleasant than random noise of similar nature. To reduce the regularity of noise generated by gears during operation, the use of gears with so-called unequal tooth pitch profiles can be considered. For prior art in this regard, see DE 35 33 743 A1.

[0005] Because the spacing between the teeth is unequal, manufacturing this tooth profile is more difficult than manufacturing a traditional tooth profile with equal pitch. Profile grinding is a hard finishing method suitable for manufacturing tooth profiles with unequal pitch, in which each tooth surface of each tooth groove needs to be ground individually to achieve the desired unequal pitch.

[0006] However, the drawback of this method is that the processing time is long, resulting in higher costs for the manufactured gears. Summary of the Invention

[0007] The object of this invention is to further improve the method of the above type, enabling the economical and high-precision manufacture of gears or workpieces with unequal tooth pitch, tooth profile, or unequal contour. Furthermore, a corresponding dressing tool is also provided.

[0008] To address the aforementioned problems, this invention proposes that when grinding gears or gear-shaped profiles with unequal tooth pitch or profiles using a multi-head grinding worm, at least three dressing surfaces on the dressing roller have unequal spacing from each other along the axis of the dressing roller, and / or at least two dressing surfaces have different shapes in the radial section.

[0009] Preferably, during the dressing process, multiple dressing surfaces (preferably all dressing surfaces) simultaneously engage with the grinding worm for at least a period of time.

[0010] According to a preferred embodiment of the invention, the tooth profile trimming surface has a tooth thickness at a reference diameter, wherein at least two tooth thicknesses are different from each other.

[0011] Alternatively, the tooth-shaped trimming surface may be configured such that it has a pitch at a reference diameter, wherein at least two pitches are different in size from each other.

[0012] Another additional or alternative implementation is that the toothed trimming surface has a maximum radial height, wherein at least two heights are different from each other.

[0013] Another possibility is that the tooth profile trimming surface has tooth face angles (side angles), wherein at least two tooth face angles are different from each other.

[0014] Preferably, all tooth thicknesses, all pitches, all heights, and all tooth face angles are different from each other.

[0015] The difference between the maximum and minimum tooth thickness is preferably at least 0.05 mm, more preferably at least 0.1 mm, and especially preferably at least 0.2 mm. Correspondingly, the difference between the maximum and minimum pitch is also preferably at least 0.05 mm, more preferably at least 0.1 mm, and especially preferably at least 0.2 mm.

[0016] The ratio between the number of teeth of the gear or gear-shaped profile and the number of threads of the grinding worm to be dressed is preferably an integer.

[0017] According to the present invention, a dressing tool for dressing a multi-head grinding worm is provided for grinding gears or gear-like profiles having unequal tooth pitch or profiles. The dressing tool is designed as a multi-groove dressing roller having multiple dressing surfaces extending around the axis of the dressing roller, and these dressing surfaces being toothed in radial section. According to the invention, at least three dressing surfaces (preferably all dressing surfaces) are arranged at unequal intervals along the axis of the dressing roller, and / or at least two dressing surfaces (preferably all dressing surfaces) have different shapes in radial section.

[0018] Furthermore, the aforementioned specifications regarding the geometric parameters that distinguish the various trimmed surfaces from each other, as well as the aforementioned dimensional proportions, also apply here.

[0019] The trimmed surface preferably has a diamond coating.

[0020] The proposed method and the structural design of the dressing roller enable rapid and precise hard finishing of gears with unequal tooth pitch profiles.

[0021] The core idea of ​​this invention is that the various dressing surfaces of the dressing roller are not all the same, but differ from each other in the following aspects, especially: position along the axis of the dressing roller, tooth thickness, tooth tip height, tooth groove depth, contact angle, gear module and / or tooth width, etc. Attached Figure Description

[0022] The accompanying drawings illustrate one embodiment of the invention. The sole drawing shows a radial section (or normal section, i.e., the axis of the dressing roller lies in the plane shown) of a multi-groove dressing roller used for dressing a multi-start grinding worm. Detailed Implementation

[0023] The accompanying drawing illustrates a dressing tool 1, which is in the form of a multi-groove dressing roller (or its upper portion). This dressing roller has multiple dressing surfaces 2, 3, and 4 that extend circumferentially around the axis a of the dressing roller 1 and are parallel to each other. The dressing surfaces 2, 3, and 4 are coated with a diamond coating, thus enabling the individual threads of the grinding worm to acquire the profile defined by the dressing surfaces 2, 3, and 4 of the dressing roller 1 when engaged with the grinding worm to be dressed.

[0024] The grinding worm, after proper dressing, is then used to hard finish the gear teeth using generating grinding methods known in the prior art.

[0025] The key point is that the three dressing surfaces 2, 3, and 4 are not exactly the same in geometry, but are arranged with different or varying pitches along the dressing roller axis a.

[0026] If we consider a reference diameter d (approximately located midway between the addendum circle and the dedendum circle of the tooth profile shown in this example), the corresponding tooth thicknesses are sn1, sn2, and sn3. According to a preferred embodiment of the invention, the tooth thicknesses have different values; that is, unlike existing solutions, these tooth thicknesses are not all the same.

[0027] Accordingly, in this embodiment, the tooth pitches (i.e., the distance between teeth) pn1, pn2, and pn3 between each tooth are also different from each other, unlike the existing solutions where they are all the same.

[0028] Furthermore, the radial height h is marked on one of the trimming surfaces (i.e., trimming surface 2). In this embodiment, the radial height h of all trimming surfaces 2, 3, and 4 is the same; however, it is also possible to set the heights of each trimming surface to be different from each other.

[0029] The same applies to the tooth angle α of dressing surfaces 2, 3, and 4, which is marked on dressing surface 3. In the illustrated embodiment, these angles are the same in magnitude, but different angles can also be set for each dressing surface 2, 3, and 4.

[0030] If such a dressing roller is used to dress a multi-head grinding worm, the grinding worm will be shaped so that when the grinding worm is subsequently used to grind gear teeth, unequal pitch gears can be obtained, that is, the tooth thickness, pitch and other geometric dimensions are not all the same, but vary.

[0031] Regarding the differences between the maximum and minimum tooth thickness and between the maximum and minimum pitch, it should be noted that when the tooth profile is ground using the grinding worm gear dressed by the dressing roller 1, these differences will cause the gear tooth pitch to shift by about 0.5°, thus forming the characteristic of unequal tooth pitch profile.

[0032] The pre-forming of the grinding worm (i.e., forming each worm thread from a cylindrical base) can be performed on a forming machine (e.g., equipment from Burri Werkzeugmaschinen GmbH und Co. KG). During this process, two tooth surfaces of each worm thread can be machined using a diamond grinding wheel. Furthermore, each worm thread can be machined separately with different profile depths and / or different rotational and / or different tangential positions and / or different tooth face angles (each maintaining a constant pitch). The aforementioned method is then used to obtain the precise profile of each grinding worm thread.

[0033] Explanation of reference numerals in the attached figures 1. Dressing tools (multi-groove dressing roller) 2. Surface finishing 3. Finish the surface 4. Finish the surface a dressing tool axis d is the reference diameter for tooth thickness. sn1 tooth thickness sn2 tooth thickness sn3 tooth thickness pn1 tooth pitch pn2 tooth pitch pn3 tooth pitch h Radial height α tooth face angle.

Claims

1. A method for grinding gears or gear-shaped profiles with unequal tooth pitch and tooth profiles using a multi-head grinding worm, wherein, The grinding worm is dressed before grinding. During the dressing process, a dressing tool (1) is engaged with the grinding worm. The dressing tool (1) is configured as a multi-groove dressing roller having multiple dressing surfaces (2, 3, 4) extending around the dressing roller axis (a). The dressing surfaces are toothed in the radial section. At least three dressing surfaces (2, 3, 4) are unevenly spaced from each other along the dressing roller axis (a), and / or at least two dressing surfaces (2, 3, 4) have different shapes in the radial section.

2. The method according to claim 1, characterized in that, During the dressing process, multiple dressing surfaces (2, 3, 4), preferably all dressing surfaces (2, 3, 4), simultaneously engage with the grinding worm for at least a period of time.

3. The method according to claim 1, characterized in that, The tooth-shaped trimmed surfaces (2, 3, 4) have tooth thicknesses (sn1, sn2, sn3) at a reference diameter (d), wherein at least two tooth thicknesses (sn1, sn2, sn3) are different from each other.

4. The method according to claim 1, characterized in that, The toothed trimming surfaces (2, 3, 4) have tooth pitches (pn1, pn2, pn3) at a reference diameter (d), wherein at least two tooth pitches (pn1, pn2, pn3) are different from each other.

5. The method according to claim 1, characterized in that, The toothed trimming surfaces (2, 3, 4) have a maximum radial height (h), wherein at least two radial heights (h) are different from each other.

6. The method according to claim 1, characterized in that, The tooth profile trimming surfaces (2, 3, 4) have tooth face angles (α), wherein at least two tooth face angles (α) are different from each other.

7. The method according to claim 1, characterized in that, All tooth thicknesses (sn1, sn2, sn3) are different from each other, and / or all tooth pitches (pn1, pn2, pn3) are different from each other, and / or all radial heights (h) are different from each other, and / or all tooth face angles (α) are different from each other.

8. The method according to claim 3, characterized in that, The difference between the maximum tooth thickness and the minimum tooth thickness (sn1, sn2, sn3) is at least 0.05 mm, preferably at least 0.1 mm, and particularly preferably at least 0.2 mm.

9. The method according to claim 4, characterized in that, The difference between the maximum tooth pitch and the minimum tooth pitch (pn1, pn2, pn3) is at least 0.05 mm, preferably at least 0.1 mm, and particularly preferably at least 0.2 mm.

10. The method according to claim 1, characterized in that, The ratio between the number of teeth of the gear or gear-shaped profile and the number of threads of the grinding worm to be dressed is an integer.

11. A dressing tool (1) for dressing a multi-head grinding worm gear for grinding a gear or gear-like profile having unequal tooth pitch or tooth profile to implement the method of any one of claims 1 to 10, wherein the dressing tool (1) is configured as a multi-groove dressing roller having a plurality of dressing surfaces (2, 3, 4) extending around a dressing roller axis (a), the dressing surfaces being toothed in a radial section, wherein at least three dressing surfaces (2, 3, 4), preferably all dressing surfaces (2, 3, 4), are arranged at uneven intervals from each other along the dressing roller axis (a), and / or at least two dressing surfaces (2, 3, 4), preferably all dressing surfaces (2, 3, 4), have different shapes from each other in a radial section.

12. The trimming tool according to claim 11, characterized in that, The tooth-shaped trimmed surfaces (2, 3, 4) have tooth thicknesses (sn1, sn2, sn3) at a reference diameter (d), wherein at least two tooth thicknesses (sn1, sn2, sn3) are different from each other, wherein preferably the difference between the maximum tooth thickness and the minimum tooth thickness (sn1, sn2, sn3) is at least 0.05 mm, preferably at least 0.1 mm, and particularly preferably at least 0.2 mm.

13. The trimming tool according to claim 11, characterized in that, The toothed surfaces (2, 3, 4) have tooth pitches (pn1, pn2, pn3) at a reference diameter (d), wherein at least two tooth pitches (pn1, pn2, pn3) are different from each other, wherein preferably the difference between the maximum tooth pitch and the minimum tooth pitch (pn1, pn2, pn3) is at least 0.05 mm, preferably at least 0.1 mm, and particularly preferably at least 0.2 mm.

14. The trimming tool according to claim 11, characterized in that, The toothed trimming surfaces (2, 3, 4) have a maximum radial height (h), wherein at least two radial heights (h) are different from each other.

15. The trimming tool according to claim 11, characterized in that, The tooth profile trimming surfaces (2, 3, 4) have tooth face angles (α), wherein at least two tooth face angles (α) are different from each other.

16. The trimming tool according to claim 11, characterized in that, The trimmed surfaces (2, 3, 4) have a diamond coating.

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