GB2078317A

GB2078317A - Multiple speed planetary gear hub

Info

Publication number: GB2078317A
Application number: GB8104358A
Authority: GB
Original assignee: RENAK WERKE VEB
Current assignee: RENAK WERKE VEB
Priority date: 1980-06-20
Filing date: 1981-02-12
Publication date: 1982-01-06
Also published as: HU189081B; CS236917B1; DE3042294A1; DD154440A3; CS267081A1; GB2078317B

Abstract

The multiple gear speed transmission hub for a bicycle comprises an axle 11, a ring gear 2, a planet wheel carrier 1 and a ratchet locking device including a pawl ring 8 with pawls 7 and a ratchet wheel 12. The ring gear 2 and planet wheel carrier 1 are selectively connectable to a driver 3 via an axially displaceable clutch sleeve 4. The clutch sleeve 4 has input and output teeth 5 and 6 of identical dimensions. The pawl ring 8 is mounted positively, but with provision for axial displacement on the ring gear 2. Displacement of the pawl ring 8 is effected by means of the clutch sleeve 4. To this end the pawl ring 8 is formed with two diametrically opposed, radially inwardly directed lugs 9 which may be engaged by the output teeth 6 of the clutch sleeve 4 and during gear operation are entrained in the direction of the driver 3. Return of the pawl ring 8 to the starting position is effected by a spring 10. <IMAGE>

Description

SPECIFICATION Multiple gear speed transmission hub This invention relates to a multiple gear speed transmission hub for bicycles and similar vehicles, having a planetary gear and an axially displaceable clutch sleeve which is selectively connectible to the ring gear or the planet wheel carrier of the planetary gear.

From German Democratic Republic Patent No. 39 861 it is known to arrange between the drive input and the output a clutch sleeve which is provided at the output with one or more toothed rings, the clutch sleeve being displaceable by a thrust block located within the toothed rings and as a result of being displaced, displaces a one-part or multi-part disc or bush, thereby disengaging a drive ratchet system driven directly by the ring gear.

From German Democratic Republic Patent No. 40 295 it is also known to form the clutch bush with drive-side teeth, always meshing with the matching teeth of the drive input, and with transmission-side teeth, meshing with the matching teeth of the transmission, the two sets of teeth having an identical addendum circle diameter, the driven tooth set having a large number of teeth with a small modulus, the drive-side tooth set having a small number of teeth and a large modulus, and the clutch bush having in the zone of the drive-side tooth set a radial bore between two teeth for receiving the thrust block. The tooth sets are produced by a double tool in one clamping operation.

The manufacture of the multiple gear speed transmission hubs is very expensive. High accuracy is required in the production of a large number of complicated components. It is also very expensive to produce the various tooth sets in the clutch bush, including the matching teeth in the drive input, ring gear and planet wheel carrier. The same applies to the arrangement of the ratchet system in an annular recess in the ring gear. A further constructional member must also be arranged between the clutch and the ratchet lock for the axial displacement thereof.

It is an object of the invention to reduce the manufacturing cost of the multiple gear speed transmission hub while at the same time ensuring high reliability and simplifying its construction.

The problem which the invention aims at solving is to develop a multiple gear speed transmission hub at reduced manufacturing cost, while maintaining reliability and without increasing the hitherto customary dimensions, with the object of obviating known disadvantages.

Accordingly, the present invention consists in a multiple gear speed transmission hub for bicycles and similar vehicles, comprising a planet wheel carrier, a ring gear with pawl ring, a driver member and an axially displaceable clutch sleeve which is continuously connected to the pawl ring, is continuously in engagement with the driver member and is alternately connectible to the planet wheel carrier or the ring gear, characterised in that the clutch sleeve has input teeth and output teeth whose addendum circle diameter and teeth are identical, and that provided on the pawl ring are diametrically opposed radially inwardly directed lugs whose inner diameter is smaller than the addendum circle diameter of the input teeth and the output teeth of the clutch sleeve.

During the operating movement of the clutch sleeve the pawl ring is entrained by the output teeth of the sleeve via the two lugs in the direction of the driver member. When the clutch sleeve moves in the opposite direction, the pawl ring is returned to its starting position by a spring. To enable the pawl ring to be mounted on the clutch sleeve, teeth are removed from the clutch sleeve input teeth, corresponding to the width of the pawl ring lugs. This can readily be done, since the input teeth are in continuous engagement with the matching teeth of the driving member.

As a result the clutch sleeve facilitates engagement of all three gear speeds, i.e. the transmission of the torque initiated via the driver member to the planet wheel carrier, or to the ring gear, and the disconnection of the pawls by shifting the pawl ring.

In order that the invention may be more readiiy understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example an embodiment thereof, and in which Figure 1 is a partial cross-section through a multiple gear speed transmission hub, and Figure 2 is a section on the line A-A of Figure 1.

Mounted on axle 11 of a multiple gear speed transmission hub are a toothed driving member 3, an axially displaceable clutch sleeve 4, a ring gear 2 and a planet wheel carrier 1. A pawl ring 8, with pawls 7 engaging a ratchet wheel 12, is mounted positively but axially displaceably on the ring gear 2.

The transmission of the torque initiated via the driver 3 is determined by the position of the axially displaceable clutch sleeve 4. At the input end the clutch sleeve 4 has input teeth 5, which mesh continuously with the matching teeth of the driver 3, and at the output end has output teeth 6, which mesh as required either with the matching teeth of the planet wheel carrier 1 or of the ring gear 2. To render manufacture simple and economic, the output teeth 6 have the same standardised splined shaft profile and the same addendum circle diameter as the input teeth 5. While the second and third gear speeds are determind by the output teeth 6 meshing with the matching teeth of the ring gear 2 or planet wheel carrier 1, for first gear speed (uphill gear speed) the pawls 7 must be disengaged from the ratchet wheel 12.This is effected by an axial displacement of the pawl ring 8 on the ring gear 2.

This displacement is effected by the clutch sleeve 4.

To this end the pawl ring 8 is formed with two diametrically opposite radially inwardly directed lugs 9 whose inner diameter is a little larger than the root circle diameter of the splined shaft profile of the clutch sleeve 4. During the gear-shifting movement of the clutch sleeve 4, the pawl ring 8 is entrained by the output teeth 6 via the two lugs 9 in the direction of the driver 3, and the pawls 7 are disengaged. This obviates the need for a separate constructional member between the clutch sleeve 4 and the pawl ring 8. The assembly of the clutch sleeve 4 and pawl ring 8 is effected in a very simple manner in that teeth are removed from the output teeth 6 of the clutch sleve 4, corresponding to the width of the lugs 9.Since in the assembled condition of the multiple gear speed transmission hub the input teeth 5 always mesh with the matching teeth of the driver 3, the tooth profile is not overloaded, nor is any separate securing needed. When the clutch sleeve 4 is moved in the direction of the planet wheel carrier 1,the pawl ring 8 is retracted by a spring 10 until it bears against the ring gear 2, so that the pawls 7 are re-engaged with the ratchet wheel 12. The pawl ring 8 can also be rotated relatively to the ring gear 2 by twice the tooth angle to prevent the mechanism from getting locked during the retraction of the ring gear 2 after braking.

The use of identical, standardised splined shaft profiles in the clutch sleeve 4 and all parts corresponding thereto reduces manufacturing cost, while at the same time the construction according to the invention simplifies the multiple gear speed transmission hub without any adverse effect on its reliability.

Claims

1. A multiple gear speed transmission hub for bicycles and similar vehicles, comprising a planet wheel carrier, a ring gear with pawl ring, a driver member and an axially displaceable clutch sleeve which is continuously connected to the pawl ring, is continuously in engagement with the driver member and is alternately connectable to the planet wheel carrier or the ring gear, characterised in that the clutch sleeve has input teeth and output teeth whose addendum circle diameter and teeth are identical, and that provided on the pawl ring are diametrically opposed radially inwardly directed lugs whose inner diameter is smaller than the addendum circle diameter of the input teeth and the output teeth of the clutch sleeve.

2. A multiple gear speed transmission hub as claimed in claim 1, wherein the pawl ring is arranged positively and axially displaceably on the ring gear.

3. a multiple gear speed transmission hub as claimed in claims 1 and 2, wherein the inputteeth of the clutch sleeve are formed with openings whose width is the same as the width of the lugs.

4. A multiple gear speed transmission hub for bicycles and similar vehicles, substantially as herein described with reference to and as shown in the accompanying drawings.