Recommended
More Related Content
What's hot
What's hot (20)
More from Kiran Wakchaure
More from Kiran Wakchaure (20)
Recently uploaded
Recently uploaded (20)
2.2 spiral gear
- 2. Sanjivani Rural Education Society’s Sanjivani College of Engineering, Kopargaon-423603 ( An Autonomous Institute Affiliated to Savitribai Phule Pune University, Pune) NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified Subject :- Theory of Machines II T.E. Mechanical (302043) Unit 2 2.2 SPIRAL GEAR By Prof. K. N. Wakchaure(Asst Professor) Department of Mechanical Engineering Sanjivani College of Engineering (An Autonomous Institute) Kopargaon, Maharashtra Email: wakchaurekiranmech@Sanjivani.org.in Mobile:- +91-7588025393
- 3. spiral gears (also known as skew gears or screw gears) are used to connect and transmit motion between two non-parallel and non-intersecting shafts. The pitch surfaces of the spiral gears are cylindrical and the teeth have point contact. These gears are only suitable for transmitting small power. helical gears, connected on parallel shafts, are of opposite hand. But spiral gears may be of the same hand or of opposite hand.
- 4. A pair of spiral gears 1 and 2, both having left hand helixes. The shaft angle θ is the angle through which one of the shafts must be rotated so that it is parallel to the other shaft, also the two shafts be rotating in opposite directions. 𝜽 = 𝑺𝒉𝒂𝒇𝒕 𝒂𝒏𝒈𝒍𝒆 = 𝜶 𝟏 + 𝜶 𝟐 For Same hand of Helix 𝜽 = 𝑺𝒉𝒂𝒇𝒕 𝒂𝒏𝒈𝒍𝒆 = 𝜶 𝟏 − 𝜶 𝟐 For Opposite hand of Helix
- 5. 𝒅 𝟏 = 𝒑𝒊𝒕𝒄𝒉 𝒄𝒊𝒓𝒄𝒍𝒆 𝒅𝒊𝒂𝒎𝒆𝒕𝒆𝒓 𝑮𝒆𝒂𝒓 𝟏 (𝒑𝒊𝒏𝒊𝒐𝒏) 𝒅 𝟐 = 𝒑𝒊𝒕𝒄𝒉 𝒄𝒊𝒓𝒄𝒍𝒆 𝑫𝒊𝒂𝒎𝒆𝒕𝒆𝒓 𝒐𝒇 𝑮𝒆𝒂𝒓 2 𝜶 𝟏 = 𝑯𝒆𝒍𝒊𝒙 𝒂𝒏𝒈𝒍𝒆 𝒇𝒐𝒓 𝑮𝒆𝒂𝒓 𝟏 𝜶 𝟐 = 𝑯𝒆𝒍𝒊𝒙 𝒂𝒏𝒈𝒍𝒆 𝒇𝒐𝒓 𝑮𝒆𝒂𝒓 𝟐 𝜽 = 𝑺𝒉𝒂𝒇𝒕 𝒂𝒏𝒈𝒍𝒆 = 𝜶 𝟏 + 𝜶 𝟐 𝝎 𝟏 = 𝑨𝒏𝒈𝒖𝒍𝒂𝒓 𝒗𝒆𝒍𝒐𝒄𝒊𝒕𝒚 𝒐𝒇 𝑮𝒆𝒂𝒓 𝟏 𝝎 𝟐 = 𝑨𝒏𝒈𝒖𝒍𝒂𝒓 𝒗𝒆𝒍𝒐𝒄𝒊𝒕𝒚 𝒐𝒇 𝑮𝒆𝒂𝒓 𝟐 mn= Normal Module pn= Normal pitch mt1= Transverse module of Gear 1 mt2= Transverse module of Gear 2 pc1= Transverse pitch of Gear 1 pc2= Transverse pitch of Gear 2 Gear Ratio (G) = 𝑻𝟐 𝑻𝟏 T1and T2 = Number of teeth on gears 1 and 2, N1 and N2 = Speed of gears 1 and 2 NOTATIONS
- 6. Since the normal pitch is same for both the spiral gears, therefore
- 7. EFFICIENCY OF SPIRAL GEAR Ft1 = Force applied tangentially on the driver, Ft2= Resisting force acting tangentially on the driven, Fa1 = Axial or end thrust on the driver, Fa2 = Axial or end thrust on the driven, FN = Normal reaction at the point of contact, Φ = friction angle, R = Resultant reaction at the point of contact, and θ = Shaft angle = α1+ α2 Work input to the driver = Ft1 × π d1.N1/60 = R cos (α1 - Φ) π d1.N1/60 Ft1 R Fn α1 α1 Fa1 ϕ
- 8. EFFICIENCY OF SPIRAL GEAR Ft1 = Force applied tangentially on the driver, Ft2= Resisting force acting tangentially on the driven, Fa1 = Axial or end thrust on the driver, Fa2 = Axial or end thrust on the driven, FN = Normal reaction at the point of contact, Φ = friction angle, R = Resultant reaction at the point of contact, and θ = Shaft angle = α1+ α2 Work input to the driven gear = Ft × π d2.N2/60 = R cos (α2 + Φ) π d2.N2/60 Ft2 Fn α2 Rα2
- 9. EFFICIENCY OF SPIRAL GEAR Ft1 = Force applied tangentially on the driver, Ft2= Resisting force acting tangentially on the driven, Fa1 = Axial or end thrust on the driver, Fa2 = Axial or end thrust on the driven, FN = Normal reaction at the point of contact, Φ = friction angle, R = Resultant reaction at the point of contact, and θ = Shaft angle = α1+ α2 Work input to the driver = Ft1 × π d1.N1/60 = R cos (α1 - Φ) π d1.N1/60 Work input to the driven gear = Ft2 × π d2.N2/60 = R cos (α2 + Φ) π d2.N2/60 Ft1 Ft2 Fn Fn R Fa1 Fn Fn R
- 10. As and Ft1 Fn Fn R Fa1 Ft1 R Fa2 α2 α1 θ ϕ α1 α2 ϕ α1 Work input to the driver = Ft1 × π d1.N1/60 = R cos (α1 - Φ) π d1.N1/60 Work input to the driven gear = Ft2 × π d2.N2/60 = R cos (α2 + Φ) π d2.N2/60
- 11. Maximum Efficiency Since the angles θ and φ are constants, therefore the efficiency will be maximum, when cos (α1 – α2 – φ) is maximum, i.e. Ft1 Fn Fn R Fa1 Ft1 R Fa2 α2 α1 θ ϕ α1 α2 ϕ
- 12. 12 Subject :- Theory of Machines II