GB2045395A

GB2045395A - Load distributing devices for gear transmissions

Info

Publication number: GB2045395A
Application number: GB8008371A
Authority: GB
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1979-03-27
Filing date: 1980-03-12
Publication date: 1980-10-29
Also published as: GB2045395B; IT1141698B; IT8046826A0; DE2911987A1; DE2911987C2

Abstract

A drivable shaft 1 has a ring 21 keyed thereon, and gear wheels 3, 4 freely mounted for rotation thereon. Gear teeth 23, 33, 43 on the faces of the ring 21 and gear wheels 3, 4 provided positive engagement therebetween. A gap 5 between the teeth allows limited axial movement between the sets of teeth. The device is suitable for gear transmissions having simultaneous output transmitting gear trains and permits relative circumferential movement of the gear wheels to distribute the load equally. Modifications include arranging a ring (21', 21'') outside each gear wheel, and replacing gear teeth 23, 33, 43 by chamfered pins (8) or balls (11) held in bores in the ring and engaging recesses in the faces of the gear wheels. <IMAGE>

Description

SPECIFICATION Load dist;ibution devices The invention relates to load distribution devices for gear transmissions having simultaneous output transmitting gear chains.

Such devices load the gear chains equally, and even out manufacturing tolerances.

A device according to the invention comprises a drivable shaft, a ring or rings nonrotatably arranged on the shaft, gear wheels rotatably mounted on the shaft, and means on faces of the ring(s) and of the gear wheels providing positive engagement therebetween, limited axial movement between the said means and the shaft being possible. Such a device can be of simple and rugged constructional form, small size and limited expense.

The means providing positive engagement may comprise straight-toothed or helical gearing or a bolt or ball receivable in a bore through the ring and in recesses in the faces of the gear wheels. A ring may be arranged between two gear wheels or a ring outside each gear wheel on the shaft. The latter arrangements make it possible for the input shaft to be short. The shaft may be a main shaft or a lay shaft. The transmission may include a dog clutch, locking dog clutch, a synchronized or locking synchronized clutch.

Thq gear teeth should be designed with deflecting surfaces inclined to the axis of the shaft at an angle such as to permit the elimination of any possible play between the shaft and the gear wheels. The deflecting surfaces may be straight, curved or helical and may take the form of radial serrations over all or part of the circumference of the relevant member.

In a device according to the invention, the shafts, gears and rings are all radially fixed, and most are axially fixed, the exceptions being necessary to provide the essential limited axial movement. This radial fixing makes possible all kinds of gear change, including synchronized changes by means of simple synchronizing or locking synchronizing clutches. Transmissions containing such devices may have one or more inner shafts.

DRAWINGS: Figure 1 is a section through a load distribution device according to the invention; Figure 2 is a cross section on Il-Il of Figure 1; Figure 3 is a section through a second load distribution device according to the invention; Figure 4 is a cross-section on IV--IV of Figure 3; Figures 5 and 6 are sections through halves of third and fourth load distribution devices according to the invention; and Figures 7 and 8 are stick diagrams of gear transmissions including load distributing devices according to Figure 1 respectively on the input and lay shafts.

In Figures 1 and 2, a ring 21 of a load distribution device 2 is non-rotatably but axially movably arranged on a driven shaft (input shaft or layshaft) and equipped with teeth 23 on the faces '22 over the entire circumference. Gear wheels 3, 4 additionally equipped with toothings 33, 43 on their inside faces 32, 42 are mounted on the driven shaft 1 in such a way that a gap 5 remains between the tooth base 24, 34, 44 and the tooth head 25, 35, 45. The gap Spermits axial movement of the ring 21 and, due to the deflecting surfaces 26, 36, 46 (tooth profiles) arranged at an angle of between 0 and 90 to the axis of the input shaft 1, also relative movement of the gear wheels 3, 4. The deflecting surfaces 26, 36, 46 (tooth profiles) may be straight but also bent.

Figures 3 and 4 differ from Figures 1 and 2, in that two rings 21 21" driven by the input shaft 1 are arranged on the outside of gear wheels 3', 4'.

The inside faces of the rings 21 21" have teeth 23', 23" cooperating with the teeth 33', 43' of the gear wheels 3' and 4'. The teeth are situated inside and are axially movable and so facilitate relative movement of the gear wheels 3'. 4' in a circumferential direction.

In Figure 5 load distribution device 7 comprises a ring 71 fixed to a driven shaft 6 and having bores 72 distributed around the circumference for receiving double-ended cone-tipped bolts. The bolts 8 are axially movable in the bores 72. With this arrangement the conically shaped 81 tips of the bolts 8 cooperate with conical recesses 91, 101 of the gear wheels 9, 10 which are rotatably mounted on the input shaft 6, but cannot move axially. The bores and bolts can be manufactured in a simple inexpensive manner.

In Figure 6 a sphere 1.1 is arranged in a bore 72' of a ring 71' of a load distribution device 7'.

The sphere 11 cooperates with spherical segments 92, 102 of gear wheels 9', 10'. In all other respects the construction of the load distribution device 7' corresponds to the load distribution device 7 illustrated in Figure 5. The sphere 11 can be manufactured simply and inexpensively.

Figure 7 shows a driven shaft 1 which is also the input shaft. The load distribution device 2, which is non-rotatably but axially connected with this input shaft 1, cooperates with the gear wheels 3, 4 mounted on the input shaft on either side of the load distribution device 2. The distribution of output is achieved by transmitting the drive to an output shaft 80 via the gear chains 20, 30, 40 or 50, 60, 40 and a clutch 70. Gear wheels 20, 30 and 50, 60 are fixed on associated layshafts 90, 100.

In Figure 8 the load distribution device 2' is arranged on the layshaft 1' which is also the driven shaft in connection with the load distribution device. Drive is transmitted to the layshaft 1' via the input shaft and the gear wheels 120, 1 30. Output is transmitted to an output shaft 80' and distributed via gear wheels 3, 4 and gear chains 140, 150, 160, 170 or 170.

The load distribution according to Figures 1 and 2 works as follows: The ring 21 of the load distribution device 2 is driven via the shaft 1. The teeth 23 on both faces 22 of the ring 21 act upon the teeth 33, 43 of the gear wheels 3, 4 and, in turn, move these in a circumferential direction. If one imagines that the gear wheels 40 (Figure 7) and 170 (Figure 8) which are both mounted on the output shaft 80, 80', are halted, it is easy to understand that the load distribution device distributes the drive moment evenly across both chains. As soon as all play has been evened out in one chain, the tooth 23 (deflecting surface) meets with resistance from e.g. the teeth 43 (deflecting surfaces) of gear wheel 4.Due to the shape of the tooth profiles 23, 43, the ring 41 can therefore give way only in axial direction, and due to the tooth profiles (deflecting surfaces 23, 33) ensures a further rotational movement of the gear wheel 3.

If there is sufficient play between the tooth base 34,44 and the tooth head 35, 45, the gear wheel 3 can continue to rotate, until there is no play left in the second chain. The guaranteed even distribution of the drive moment onto both gear chains is thus always due to the design, and results in an evening out of all tolerances during running and thus continuously.

The load distribution according to Figures 3 and 4 is the same in principle. The axial compensating movement is effected by the rear wheels 3', 4' themselves, and allowances have to be made with regard to the tooth width on these wheels in relation to the connecting gear wheels of the gear chains.

The load distribution devices of Figures 5 and 6 work on the same principle. Here the axial compensating movement is effected by the double-ended cone-tipped bolt 8 and by the sphere 11, and the whole transmission can be made of short axial length. In an alternative arrangement, the bolts have a conical tip at one end only, and may be firmly attached with a straight end to a ring or even to a gear wheel.

Claims

1. A load distribution device for a gear transmission comprising a drivable shaft, a ring or rings non-rotatably arranged on the shaft, gear wheels rotatably mounted on the shaft, and means on faces of the ring(s) and of the gear wheels providing positive engagement therebetween, limited axial movement between the said means and the shaft being possible.

2. A device according to claim 1 in which the said means comprises gear teeth.

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3. A device according to claim 1 in which the said means comprises a bolt or ball receivable in a bore through the ring and in recesses in the faces of the gear wheels.

4. A device according to any preceding claim in which a ring is arranged between two gear wheels on the shaft.

5. A device according to claim 1 or claim 2 in which a ring is arranged outside each gear wheel on the shaft.

6. A load distributing device as herein described with reference to Figures 1 and 2 of the drawings.

7. A load distributing device as herein described with reference to Figures 3 and 4 of the drawings.

8. A load distributing device as herein described with reference to Figure 5 of the drawings.

9. A load distributing device as herein described with reference to Figure 6 of the drawings.

10. A gear transmission including a load distributing device according to any preceding claim.