Helical gear pairing for a helical gear unit, pairing and use thereof

Patent metadata

Field	Value
Publication number	US-11549578-B2
Application number	US-201815987642-A
Country	US
Kind code	B2
Filing date	May 23, 2018
Priority date	May 24, 2017
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A gear pairing for a helical gear unit or a spur gear unit, comprising a first gear with a first toothing portion, and a second gear with a second toothing portion, wherein the first gear has a first axis and the second gear has a second axis, which enclose a shaft angle, which is between 0 and 90°, the first toothing portion and the second toothing portion can be brought into meshing engagement and, when engaged, form an involute toothing, the materials of the first and second toothing portions are chosen so that, when engaged, a material pairing metal/plastic results, and the toothing portion made of plastic has a first helix angle and the toothing portion made of metal has a second helix angle.

First claim

What is claimed:

1. A gear pairing for a helical gear unit, comprising:
a first gear having a first toothing portion within which a number of first teeth are located and a first axis and wherein the first teeth have a front side and a back side;
a second gear having a second toothing portion within which a number of second teeth are located and a second axis, wherein the first axis and the second axis enclose a shaft angle (χ) that is 90°;
wherein the first teeth and the second teeth meshingly engage at only a single contact point located either on the front side or the back side of the first teeth such that a backlash is formed, the first teeth and the second teeth forming an involute toothing when engaged;
wherein the first toothing portion is formed of a material selected from the group consisting of plastic or metal, and the second toothing portion is formed of the material selected from the group consisting of plastic or metal and which is different than the material of the first toothing portion such that when the first toothing portion and the second toothing portion meshingly engage, a material pairing of metal/plastic results, and
wherein the toothing portion formed of plastic consists of a single plastic helix angle (β 1 ) and the toothing portion formed of metal consists of a single metal helix angle (β 2 ),
wherein a difference (Δβ) between an absolute value of the plastic helix angle (|β 1 |) and an absolute value of the metal helix angle (|β 2 |)
is for the helical gear unit with the shaft angle (χ) of 90°: Δβ=|β 1 |−|β 2 |=90°−χ±K≠90°−χ,

wherein 0.5°≤K≤5°.

2. The gear pairing for the helical gear unit according to claim 1 ,
wherein a reference profile has a reference helix angle (β r ),
wherein the plastic helix angle (β 1 ) is different from the reference helix angle (β r ), the metal helix angle (β 2 ) is different from the reference helix angle (β r ) or both the plastic helix angle (β 1 ) is different from the reference helix angle (β r ) and the metal helix angle (β 2 ) is different from the reference helix angle (β r ), the reference profile being defined as follows:

Reference profile 1

Worm
Helical gear

Number of teeth z
2
13

Helix angle β r [°]
12.6608
12.6608

Normal pressure angle α] n [°]
21.0000
21.0000

Normal module m n [mm]
0.9800

Pitch diameter d 0 [mm]
8.94
13.06

Addendum factor h a
1.1255
0.8530

Dedendum factor h f
1.2214
1.2400

Profile modification factor x
−0.3053
0.1647

Tip diameter d a [mm]
10.550
15.052

Root diameter d f [mm]
5.950
10.950

3. The gear pairing for the helical gear unit according to claim 1 ,
wherein the first gear is formed as a worm gear and the second gear is formed as a helical gear and the helical gear or the worm are connected to a drive shaft;
wherein the first toothing portion of the worm and the second toothing portion of the helical gear are meshingly engaged.

4. The gear pairing for the helical gear unit according to claim 3 , wherein the helical gear is made of metal, is formed as a spindle nut and interacts with a spindle, and wherein the worm is made of plastic.

5. The gear pairing for the helical gear unit according to claim 3 , wherein 1°≤K≤3°.

6. A gear pairing for a helical gear unit, comprising:
a first gear having metal teeth and a first axis and wherein the metal teeth have a front side and a back side;
a second gear having plastic teeth and a second axis, wherein the first axis and the second axis enclose a shaft angle (χ) that is between 0° and 90°;
wherein the metal teeth and the plastic teeth meshingly engage at only a single contact point located either on the front side or the back side of the first teeth such that a backlash is formed, the first teeth and the second teeth forming an involute toothing when engaged;
wherein the metal teeth and the plastic teeth meshingly engage to a metal to plastic pairing;
wherein the plastic teeth consists of a single plastic helix angle (β 1 ) and the metal teeth consists of a single metal helix angle (β 2 ),
wherein a difference (Δβ) between an absolute value of the plastic helix angle (|β 1 |) and an absolute value of the metal helix angle (|β 2 |)
is for the helical gear unit with the shaft angle (χ) of 45 to 90°: =|β 1 |−|β 2 |=90°−χ±K≠90°−χ, and
is for the helical gear unit with the shaft angle (χ) of 0 to 45°: Δβ=|β 1 |−|β 2 |=−χ±K≠0°−χ,
wherein 0.5°≤K≤5°,

wherein a reference profile has a reference helix angle (β r ),
wherein the plastic helix angle (β 1 ) is different from the reference helix angle (β r ), and wherein the metal helix angle (β 2 ) comprises the reference helix angle (β r )

Reference profile 1

Worm
Helical gear

Number of teeth z
2
13

Helix angle β r [°]
12.6608
12.6608

Normal pressure angle α] n [°]
21.0000
21.0000

Normal module m n [mm]
0.9800

Pitch diameter d 0 [mm]
8.94
13.06

Addendum factor h a
1.1255
0.8530

Dedendum factor h f
1.2214
1.2400

Assignees

• Ims Gear Se & Co Kgaa

Inventors

• Aberle Steffen
• Melnikov Egor
• Fechler Jens

Classifications

• F16H1/08 Primary

  the members having helical, herringbone, or like teeth · CPC title

• F16H55/17

  Toothed wheels (worm wheels F16H55/22; chain wheels F16H55/30) · CPC title

• F16H2055/065

  Moulded gears, e.g. inserts therefor · CPC title

• F16H55/08 Primary

  Profiling · CPC title

• F16H55/06

  Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties · CPC title