GB2432632A

GB2432632A - A gearing arrangement for a rotary engine

Info

Publication number: GB2432632A
Application number: GB0524034A
Authority: GB
Inventors: James Black
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-25
Filing date: 2005-11-25
Publication date: 2007-05-30
Also published as: GB0524034D0

Abstract

A gearing arrangement 50 for a rotary Wankel-type engine comprising a first gear 52 engaging an output shaft 30 such that the first gear rotates therewith, a rotor engaging member 54 for rotation with a triangular rotor and speed reduction means between the first gear and the rotor engaging member for linking the shaft and rotor engaging member such that the rotor engaging member rotates at a lower speed than the shaft. The speed reduction means comprises a sleeve 64 rotatable relative to the shaft and linking the rotor engaging member with a second gear 62 which drives the first gear through a countershaft 76 auxiliary gearing device 70 which has third 72 and fourth 74 gears connected by a sleeve. The gearing teeth are selected to give a shaft/rotor ratio of 3:1. The gearing allows a thicker, thus stronger, output shaft and is suitable for compression ignition engines.

Description

1 Gearing Apparatus for a Rotary Engine 3 The present invention relates

to rotary engines. In 4 particular, but not exclusively, the invention relates to gearing for the rotor of a diesel rotary 6 engine.

8 Rotary engines utilise at least one triangular rotor 9 contained within an epitrochoidal housing. The rotor is mounted on the eccentric lobe of an output 11 shaft. During combustion, the rotor is forced 12 against the output shaft. Due to the eccentricity 13 of the lobe, a torque is created which rotates the 14 output shaft.

16 Conventionally, the rotor includes internal gear 17 teeth which mesh with a stationary gear connected to 18 the housing and rotatably mounted on the output 19 shaft. The stationary gear controls the motion of the rotor in the sense that it determines the path 21 and direction of the rotor as the rotor rotates and 22 orbits the stationary gear.

2 For a rotor having three apices defining three 3 combustion chambers, the ratio of the rotational 4 speed of the output shaft and the rotor must be 3:1.

This ratio is achieved by selecting an appropriate 6 diameter and number of teeth for each of the 7 stationary gear and the internal gear teeth of the 8 rotor. However, maintaining this ratio imposes an 9 upper limit on the diameter of the stationary gear.

Since this is mounted on the output shaft, an upper 11 limit is also imposed on the diameter of the output 12 shaft.

14 Particularly for diesel engines which involve higher compression loads, it is often desirable to increase 16 the diameter of the output shaft.

18 According to a first aspect of the present 19 invention, there is provided a gearing apparatus for a rotary engine comprising: 21 a first gear engageable with the output shaft 22 of the rotary engine such that the first gear 23 rotates at the rotational speed of the output shaft; 24 a rotor drive member engageable with the rotor of the rotary engine; and 26 speed reduction means interposed between the 27 first gear and the rotor drive member for rotating 28 the rotor drive member at a rotational speed less 29 than the rotational speed of the first gear.

31 The term "gear" is intended to encompass a broad 32 range of devices or arrangements which fulfil the 1 function of a gear. For instance, the first gear 2 may comprise a plurality of notches or recesses 3 provided circumferentially around the output shaft 4 which provide teeth engageable with the speed reduction means. Also, the term "engageable with" 6 and the like should not be construed as necessarily 7 intending a direct connection. Rather, the term 8 conveys a functional relationship for coupled 9 rotation and there may be intermediary components.

11 Preferably the rotor drive member is rotatably 12 mountable to the output shaft.

14 Preferably the first gear is fixedly mountable to the output shaft.

17 Preferably the speed reduction means comprises a 18 second gear fixedly connected to the rotor drive 19 member. Alternatively, the second gear engages with the rotor drive member. Preferably the second gear 21 is rotatably mountable to the output shaft.

22 Preferably the second gear is fixedly connected to 23 the rotor drive member by a sleeve member.

24 Alternatively, the second gear may be an integral portion of the rotor drive member.

27 Preferably the gearing apparatus includes an 28 auxiliary gearing device and the second gear is 29 engageable with the first gear via the auxiliary gearing device. Alternatively the second gear may 31 be directly engageable with the first gear.

1 Preferably the auxiliary gearing device comprises 2 one or more gears mounted to a countershaft.

3 Preferably the auxiliary gearing device comprises a 4 third gear mounted to the countershaft and engageable with the first gear. Preferably the 6 auxiliary gearing device comprises a fourth gear 7 mounted to the countershaft and engageable with the 8 second gear. Alternatively the third gear may be 9 engageable with the second gear.

11 Preferably the gearing apparatus includes a first 12 bearing for rotatably supporting the rotor drive 13 member at the output shaft. Preferably the second 14 gear is rotatably supported by the first bearing.

Preferably the sleeve member is rotatably supported 16 by the first bearing.

18 Preferably the rotary engine includes a shaft 19 bearing for rotatably supporting the output shaft, and the shaft bearing interposes the second gear and 21 the rotor drive member. Preferably the sleeve 22 member interposes the shaft bearing and the output 23 shaft.

According to a second aspect of the present 26 invention, there is provided a rotary engine 27 including a gearing apparatus in accordance with the 28 first aspect of the invention.

Preferably the rotary engine includes an oversized 31 output shaft.

1 According to a third aspect of the present 2 invention, there is provided a method of controlling 3 the motion of a rotor of a rotary engine comprising: 4 providing a first gear at the output shaft of the rotary engine such that the first gear rotates 6 at the rotational speed of the output shaft; 7 engaging a rotor drive member with the rotor; 8 and 9 connecting the first gear and the rotor drive member via speed reduction means such that the rotor 11 drive member is rotatable at a rotational speed less 12 than the rotational speed of the first gear.

14 Preferably the method includes rotatably mounting the rotor drive member to the output shaft.

17 Preferably the method includes fixedly mounting the 18 first gear to the output shaft.

Preferably the step of connecting the first gear and 21 the rotor drive member via speed reduction means 22 includes fixedly connecting a second gear to the 23 rotor drive member. Preferably the method includes 24 rotatably mounting a second gear to the output shaft. Preferably the method includes fixedly 26 connecting the second gear to the rotor drive member 27 by a sleeve member.

29 Preferably the method includes providing an auxiliary gearing device and engaging the second 31 gear with the first gear via the auxiliary gearing 32 device.

2 Preferably the auxiliary gearing device comprises 3 one or more gears mounted to a countershaft.

4 Preferably the auxiliary gearing device comprises a third gear mounted to the countershaft and 6 engageable with the first gear. Preferably the 7 auxiliary gearing device comprises a fourth gear 8 mounted to the countershaft and engageable with the 9 second gear.

11 An embodiment of the present invention will now be 12 described, by way of example only, with reference to 13 the accompanying drawings, in which: Fig. 1 shows a sectional end view of a rotary engine

16 in accordance with the prior art;

18 Fig. 2 shows a sectional end view of a rotary engine 19 in accordance with a second aspect of the present invention; 22 Fig. 3 shows a sectional side view of a gearing 23 apparatus in accordance with a first embodiment of a 24 first aspect ot the present invention; and 26 Fig. 4 shows a sectional side view of a gearing 27 apparatus in accordance with a second embodiment of 28 a first aspect of the present invention.

Referring to Fig. 1, there is shown a known rotary 31 engine 100. The engine comprises an epitrochoidal 32 housing 12 and a rotor 20 mounted on the eccentric 1 lobe 24 of an output shaft 130 within the housing 2 12.

4 The rotor 20 is substantially triangular and has an aperture 22 at its centre. The aperture 22 is 6 provided with number of internal gear teeth (not 7 shown) around its circumference. A stationary gear 8 140 is rotatably mounted on the output shaft 130 and 9 connected to the housing 12. The stationary gear 140 is provided with external teeth (not shown) and 11 these mate with the teeth of the rotor 20. The 12 rotor 20 and gear 140 co-operate such that, as the 13 rotor 20 rotates within the housing 12, it orbits 14 the stationary gear 140. Therefore, there is rotation and vertical and horizontal movement of the 16 rotor 20 relative to the stationary gear 140.

18 Fig. 2 shows a rotary engine 10 according to the 19 invention. Like components are given like reference numerals. The rotary engine 10 is similar to the 21 prior art rotary engine 100. However, the rotary 22 engine 10 of the invention includes a gearing 23 apparatus 50 which is shown in Fig. 3. This allows 24 inclusion in the rotary engine 10 of an oversized rotor drive gear 40 and hence output shaft 30.

26 These components are oversized in the sense that 27 they have a significantly greater outer diameter 28 than conventional components.

The gearing apparatus 50 of the rotary engine 10 31 includes a first gear 52 which is fixedly mounted to 32 the output shaft 30 of the rotary engine 10 so that 1 the first gear 52 rotates at the rotational speed of 2 the output shaft 30. The gearing apparatus 50 also 3 includes a rotor drive member 54 which is rotatably 4 mounted on the output shaft 30 and engages with the hub 23 of the rotor 20 of the rotary engine 10.

7 Speed reduction means 60 is provided between the 8 first gear 52 and the rotor drive member 54 for 9 rotating the rotor drive member 54 at a rotational speed less than the rotational speed of the first 11 gear 52. The speed reduction means 60 comprises a 12 second gear 62 rotatably mounted on the output shaft 13 30 and fixedly connected to the rotor drive member 14 54 by a sleeve member 64.

16 In the embodiment of Fig. 3, the first gear 52 17 meshes with the second gear 62. This may be using a 18 planetary gearing arrangement, or any other gearing 19 arrangement which allows the second gear 62 to rotate in the same direction, but at a lower 21 rotational speed, than that of the first gear 52 and 22 output shaft 30. The rotor drive member 54 is 23 directly connected to the second gear 62 by the 24 sleeve member 64 and so rotates at the rotational speed of the second gear 62. A suitable gearing 26 arrangement is selected to provide the ratio of the 27 rotational speed of the output shaft and the rotor 28 of 3:1.

If the rotor drive member 54 were stationary, as in 31 the prior art, its greater diameter would mean that 32 the required ratio of 3:1 could not be achieved. By 1 rotating the rotor drive member 54 at the 2 appropriate speed and in the same direction as the 3 output shaft 30, the required ratio is maintained.

Fig. 4 shows a second embodiment of the gearing 6 apparatus 50. In this embodiment, the gearing 7 apparatus 50 includes an auxiliary gearing device 8 70. The second gear 62 is coupled to the first gear 9 52 via the auxiliary gearing device 70.

11 The auxiliary gearing device 70 comprises a third 12 gear 72 and a fourth gear 74 fixedly mounted on a 13 countershaft 76. The third gear 72 meshes with the 14 first gear 52 and the countershaft 76 rotates at a rotational speed which is a function of the 16 rotational speed of the output shaft 30 and the 17 ratio of the number of teeth of the third gear 72 18 and the first gear 52. The countershaft 76 rotates 19 in an opposite direction to the output shaft 30.

21 The fourth gear 74 also rotates at the rotational 22 speed of the countershaft 76 and meshes with the 23 second gear 62. The rotor drive member 54, being 24 directly connected to the second gear 62 by the sleeve member 64, rotates at a rotational speed 26 which is a function of the rotational speed of the 27 countershaft 76 and the ratio of the number of teeth 28 of the fourth gear 74 and the second gear 62. The 29 rotor drive member 54 rotates in an opposite direction to the countershaft 76 and in the same 31 direction as the output shaft 30.

1 The number of teeth of each of the gears 52, 72, 74, 2 62 is selected to provide the overall ratio of the 3 rotational speed of the output shaft and the rotor 4 of 3:1. The auxiliary gearing device 70 provides greater flexibility for achieving this ratio. Also, 6 a simpler arrangement of spur gears with external 7 meshing teeth may be used.

9 As for the first embodiment, the rotor drive member 54 can be driven at the appropriate speed and in the 11 same direction as the output shaft 30 to maintain 12 the required ratio.

14 There are many possible design options for maintaining the required ratio. One option is to 16 provide first 52 and third 72 gears which have an 17 equal number of gear teeth. Therefore, the output 18 shaft 30 and countershaft 76 rotate at the same 19 speed but in opposite directions. The third 72 and fourth 74 gears also rotate at the same speed as the 21 countershaft 76.

23 The number of teeth of the fourth gear 74 and second 24 gear 62 are selected to provide a ratio of 4/9.

Therefore, the second gear 62, sleeve member 64 and 26 rotor drive member 54 all rotate at a speed which is 27 4/9 that of the output shaft 30 (and in the same 28 direction) The size of the rotor is selected such that it 31 rotates at 3/4 the speed of the rotor drive member 32 54. This gives an overall required ratio of 3:1.

2 A first bearing 80 is provided for rotatably 3 supporting the second gear 62, sleeve member 64 and 4 rotor drive member 54 at the output shaft 30.

6 The rotary engine includes a shaft bearing 82 for 7 rotatably supporting the output shaft 30. The shaft 8 bearing 82 is provided between the second gear 62 9 and the rotor drive member 54 and between the sleeve member 64 and a housing end piece (not shown) 12 Various modifications and improvements can be made 13 without departing from the scope of the present 14 invention.

Claims

1 CLAIMS 3 1. A gearing apparatus for a rotary engine 4 comprising: a

first gear engageable with the output shaft 6 of the rotary engine such that the first gear 7 rotates at the rotational speed of the output shaft; 8 a rotor drive member engageable with the rotor 9 of the rotary engine; and speed reduction means interposed between the 11 first gear and the rotor drive member for rotating 12 the rotor drive member at a rotational speed less 13 than the rotational speed of the first gear.

2. A gearing apparatus as claimed in Claim 1, 16 wherein the rotor drive member is rotatably 17 mountable to the output shaft.

19 3. A gearing apparatus as claimed in Claim 1 or 2, wherein the first gear is fixedly mountable to the 21 output shaft.

23 4. A gearing apparatus as claimed in any preceding 24 claim, wherein Lhe speed reducLion means comprises a second gear fixedly connected to the rotor drive 26 member.

28 5. A gearing apparatus as claimed in Claim 4, 29 wherein the second gear is rotatably mountable to the output shaft.

1 6. A gearing apparatus as claimed in Claim 4 or 5, 2 wherein the second gear is fixedly connected to the 3 rotor drive member by a sleeve member.

7. A gearing apparatus as claimed in any of Claims 6 4 to 6, including an auxiliary gearing device and 7 the second gear is engageable with the first gear 8 via the auxiliary gearing device.

8. A gearing apparatus as claimed in Claim 7, 11 wherein the auxiliary gearing device comprises one 12 or more gears mounted to a countershaft.

14 9. A gearing apparatus as claimed in Claim 8, wherein the auxiliary gearing device comprises a 16 third gear mounted to the countershaft and 17 engageable with the first gear.

19 10. A gearing apparatus as claimed in Claim 8 or 9, wherein the auxiliary gearing device comprises a 21 fourth gear mounted to the countershaft and 22 engageable with the second gear.

24 Ii. A rotary engine including a gearing apparatus in accordance with any of Claims 1 to 10.

27 12. A rotary engine as claimed in Claim 11, 28 including an oversized output shaft.

13. A method of controlling the motion of a rotor 31 of a rotary engine comprising: 1 providing a first gear at the output shaft of 2 the rotary engine such that the first gear rotates 3 at the rotational speed of the output shaft; 4 engaging a rotor drive member with the rotor; and 6 connecting the first gear and the rotor drive 7 member via speed reduction means such that the rotor 8 drive member is rotatable at a rotational speed less 9 than the rotational speed of the first gear.

11 14. A method as claimed in Claim 13, including 12 rotatably mounting the rotor drive member to the 13 output shaft.

15. A method as claimed in Claim 13 or 14, 16 including fixedly mounting the first gear to the 17 output shaft.

19 16. A method as claimed in any of Claims 13 to 15, wherein the step of connecting the first gear and 21 the rotor drive member via speed reduction means 22 includes fixedly connecting a second gear to the 23 rotor drive member.

17. A method as claimed in Claim 16, including 26 rotatably mounting the second gear to the output 27 shaft.

29 18. A method as claimed in Claim 16 or 17, including fixedly connecting the second gear to the 31 rotor drive member by a sleeve member.

1 19. A method as claimed in any of Claims 16 to 18, 2 including providing an auxiliary gearing device and 3 engaging the second gear with the first gear via the 4 auxiliary gearing device.

6 20. A method as claimed in Claim 19, wherein the 7 auxiliary gearing device comprises a third gear 8 mounted to the countershaft and engageable with the 9 first gear.

11 21. A method as claimed in Claim 19 or 20, wherein 12 the auxiliary gearing device comprises a fourth gear 13 mounted to the countershaft and engageable with the 14 second gear.