GB2150665A - Reduction gearing - Google Patents

Abstract

A reduction gearing arrangement has two pairs of gears, a pinion PG engaged with the larger pair of gears FFG and FSG and an idler gear IG engaged with the smaller pair of gears SFG and SSG. The pinion PG is connected with the input shaft IPS. The idler gear IG is freely rotating on a shaft IDS, which is connected with an output shaft OS at right angles. The gears FFG, SFG and FSG, SSG are contra-rotating by the rotation of pinion gear PG. The output shaft OS rotates around the axis of the two pairs of gears FFG and SFG, FSG and SSG. The numbers of teeth of the larger gears FFG and FSG are different from one another, as are the numbers on the smaller gears SFG, SSG. The arrangement can be employed in any application requiring exceptionally high reduction or increase of ratios and high mechanical efficiency. <IMAGE>

Description

SPECIFICATION Differential gearbox This invention relates to gearboxes and in particular to differential gearboxes.

Gearboxes are well known mechanical devices used for reduction or increase of speed of associated shafts.

There are many types of existing gearboxes in industrial use today especially serving as reduction devices. However the existing gearboxes with very high ratio of reduction or increase in today's use have the disadvantage of low mechanical efficiency as for example in warm gearboxes and large trains of rotating components as in arrangement of straight cut gear gearboxes.

The advantage of the differential gearbox described in this invention is in very simple mechanical arrangement with very high mechanical efficiency. A very high ratio as for example 1 20,000:1 is possible to obtain practically with an arrangement of only two pairs of gears.

According to the present invention, there is provided a differential gearbox comprising a pair of first large gear wheels, each with different number of teeth, situated on the same concentric shaft, with the gear teeth provided on their inner faces near the circumference of the said pair of first large gear wheels, a pinion, serving as an input shaft situated between the said first pair of larger gear wheels and being engaged in their teeth, the pinion axis being at right angles to the axis of the said first pair of larger gear wheels and a second pair of two smaller wheels permanently attached to the said first pair of large gear wheels, each having different number of teeth and being on the common axis with the said first pair of larger wheels and having their teeth provided on the internal faces similarity like the first pair of large gear wheels and an idler gear being engaged with the said second pair of smaller gear wheels and having its shaft at right angles to the axis of the said first and second gear wheels and its shaft being permanently attached to the output shaft situated in the centre axis of the said first and second pairs of gear wheels.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: FFG and FSG is the said first pair of gears; SFG and SSG is the said second pair of gears; IG is idler gear; IDS is idler gear shaft; OS is output shaft; PG is pinion gear; IPS is input shaft; Referring to the accompanying drawing the gearbox comprises a first pair of gears FFG and FSG, a pinion PG being engaged with the first pair of gears FFG and FSG and permanently connected to input shaft IPS, a second pair of gears SFG and SSG, and an idler gear IG being engaged with the said second pair of gears SFG and SSG and being free rotating on the shaft IDS and the shaft IDS being permanently connected at right angles to output shaft OS.

1. A differential gearbox comprising first pair of larger gears, each gear having different number of teeth, the said gears situated on the common concentric shaft and having their gear teeth provided on their inner faces near the circumference and a pinion gear situated there between and being in gear engagement with the said first larger gears, the pinion gear serving as input shaft so that the said first pair of larger gears is contra-rotating, and a second pair of smaller gears being permanently connected with the said first pair of larger gears, each having different number of teeth and the said second pair of smaller gears being engaged in gear teeth with an idler gear situated there between the idler gear being free rotating on the shaft, the shaft being permanently connected at right angles to the output shaft situated on the centre axis of the said first and second pairs of gears.

2. A differential gearbox as claimed in the claim 1, wherein the said pinion gear is comprising two pinion gears, each for one of the said first pair of gears.

3. A differential gearbox as claimed in the claim 1 or claim 2, wherein the said idler gear is comprising two idler gears connected together and each being engaged with one of the said second pair of smaller gears.

4. A differential gearbox as described in the claim 1, claim 2 or claim 3, having the idler gear shaft rotating with the said idler gear.

5. A differential gearbox as described in any of the previous claims, having more than one idler gear.

6. A differential gearbox substantially as described herein with reference to the accompanying drawing.

7. A differential gearbox substantially as described elsewhere in this invention.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Differential gearbox This invention relates to gearboxes and in particular to differential gearboxes. Gearboxes are well known mechanical devices used for reduction or increase of speed of associated shafts. There are many types of existing gearboxes in industrial use today especially serving as reduction devices. However the existing gearboxes with very high ratio of reduction or increase in today's use have the disadvantage of low mechanical efficiency as for example in warm gearboxes and large trains of rotating components as in arrangement of straight cut gear gearboxes. The advantage of the differential gearbox described in this invention is in very simple mechanical arrangement with very high mechanical efficiency. A very high ratio as for example 1 20,000:1 is possible to obtain practically with an arrangement of only two pairs of gears. According to the present invention, there is provided a differential gearbox comprising a pair of first large gear wheels, each with different number of teeth, situated on the same concentric shaft, with the gear teeth provided on their inner faces near the circumference of the said pair of first large gear wheels, a pinion, serving as an input shaft situated between the said first pair of larger gear wheels and being engaged in their teeth, the pinion axis being at right angles to the axis of the said first pair of larger gear wheels and a second pair of two smaller wheels permanently attached to the said first pair of large gear wheels, each having different number of teeth and being on the common axis with the said first pair of larger wheels and having their teeth provided on the internal faces similarity like the first pair of large gear wheels and an idler gear being engaged with the said second pair of smaller gear wheels and having its shaft at right angles to the axis of the said first and second gear wheels and its shaft being permanently attached to the output shaft situated in the centre axis of the said first and second pairs of gear wheels. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: FFG and FSG is the said first pair of gears; SFG and SSG is the said second pair of gears; IG is idler gear; IDS is idler gear shaft; OS is output shaft; PG is pinion gear; IPS is input shaft; Referring to the accompanying drawing the gearbox comprises a first pair of gears FFG and FSG, a pinion PG being engaged with the first pair of gears FFG and FSG and permanently connected to input shaft IPS, a second pair of gears SFG and SSG, and an idler gear IG being engaged with the said second pair of gears SFG and SSG and being free rotating on the shaft IDS and the shaft IDS being permanently connected at right angles to output shaft OS. CLAIMS

1. A differential gearbox comprising first pair of larger gears, each gear having different number of teeth, the said gears situated on the common concentric shaft and having their gear teeth provided on their inner faces near the circumference and a pinion gear situated there between and being in gear engagement with the said first larger gears, the pinion gear serving as input shaft so that the said first pair of larger gears is contra-rotating, and a second pair of smaller gears being permanently connected with the said first pair of larger gears, each having different number of teeth and the said second pair of smaller gears being engaged in gear teeth with an idler gear situated there between the idler gear being free rotating on the shaft, the shaft being permanently connected at right angles to the output shaft situated on the centre axis of the said first and second pairs of gears.

2. A differential gearbox as claimed in the claim 1, wherein the said pinion gear is comprising two pinion gears, each for one of the said first pair of gears.

3. A differential gearbox as claimed in the claim 1 or claim 2, wherein the said idler gear is comprising two idler gears connected together and each being engaged with one of the said second pair of smaller gears.

4. A differential gearbox as described in the claim 1, claim 2 or claim 3, having the idler gear shaft rotating with the said idler gear.

5. A differential gearbox as described in any of the previous claims, having more than one idler gear.

6. A differential gearbox substantially as described herein with reference to the accompanying drawing.

7. A differential gearbox substantially as described elsewhere in this invention.