GB2040397A

GB2040397A - Universal joints

Info

Publication number: GB2040397A
Application number: GB8001774A
Authority: GB
Original assignee: Costamasnaga SpA
Current assignee: Costamasnaga SpA
Priority date: 1979-01-22
Filing date: 1980-01-18
Publication date: 1980-08-28
Also published as: IT7919490A0; FR2446957B3; ES487919A1; FR2446957A1; DE3002055A1; IT1111776B; BE881212A

Abstract

A universal joint for a roll mill drive comprises driving and driven members 1 and 13 interconnected by a ball joint 8-10. The members 1 and 13 are also torsionally connected through gear pairs 4,17; 16,17 in which the teeth 17 on a sleeve 18 have flat flanks 19 and the teeth 4, 16 on the driving and driven hubs 3, 12 have curved flanks. The member 13 is axially movable within the hub 12 against the action of a spring 15. <IMAGE>

Description

SPECIFICATION Improvements in or relating to universal joints This invention relates to improvements in or relat- ingto universal joints of the kind in which driven and driving members are interconnected by a ball joint, that is an ornikinetic joint.

It is the primary object of the present invention to improve a universal joint of the above mentioned type, which is capable of transmitting high torques with quite limited dimensions.

It is another important object of the present invention to improve a universal joint of the above mentioned type that with quite limited dimensions can be used for transmitting high torques, also in the presence of substantial misalignments or inclination between a drive shaft and the shaft of a driven device.

These and further objects, which will become more apparent from the following detailed description, are accomplished by the improvements made to universal joints, wherein the driven and driving members are interconnected by a ball joint, improvements which according to the present invention consist of torsionally coupling such members through gear pairs, each of which comprises a tooth arrangement having flat side teeth and a tooth arrangement having convex or crowned teeth and having a curvilinear and, preferably a circular, axis.

As used herein, the terms "convex or crowned tooth" are meant to define a tooth, the sides of which pertain to outwardly convex surfaces.

According to a first embodiment of the invention, the driven and driving members have an outer rim with convex or crowned teeth and a curvilinear axis, meshing with inner flat side tooth arrangements pertaining to a sleeve. The sleeve tooth arrangement may actually comprise a single tooth arrangement which is interrupted or cut off for the insertion of an annular spacer which is effective to limit the axial displacement or movement of the sleeve and maintain the latter on the bisecting line of the angle bet ween the two axes.

According to a further significant feature of the invention, it is provided in the application of the improved universal joint with an extensible connecting shaft that the driven member, as torsionally integral with said shaft but axially slidable relatively thereto, is resiliently loaded so as to retain the ball connection between said driven and driving members.

The invention will be more clearly understood from the following detailed description, given by mere way of unrestrictive example and with reference to the accompanying drawing, in which: Figure 1 is an axial sectional view showing two universal joints joined by an extensible connecting shaft; and Figure 2 is a top view schematically showing a convex or crowned tooth located in the cavity of the co-operating tooth arrangments.

Referring now to Figure 1, shown therein is a universal joint connection used, for example, for drive transmission from a reduction gear to a roll in a rolling mill, which as is well known, can be moved or displaced parallelly to itself. In the case under consideration, it is assumed that power will follow the path according to arrow A from the outlet pin 1 of a reduction gear (not shown) to the inlet pin 2 of the rolling mill.

The pin 1 has a hub 3 keyed thereto in any known manner, which at its free end externally has a ring gear 4 comprising convex or crowned teeth 5 (see Figure 2) of a curvilinear, preferably a circular longitudinal axis. Still at this end thereof, said hub 3 is secured to a ring 7 having a cylindrical extension 8.

Together said ring and extension define a ball capseat 9 accommodating a bearing of also ball cap type 10. In such a bearing there is accommodated a cylindrical extension which projects centrally from the closure wall of the hub 12. On the inner face or side such a hub has a splined engagement on a connecting shaft 13. Thus, said hub 12 and shaft 13 can slide axially relative to each other, while being torsionally integral with each other.

The above mentioned bearing 10 and relevant seat 9 define a ball joint. In order to prevent such a joint from being disconnected, an endwise mounted pusher 14 resiliently presses againstthe inner face of the closure wall of hub 12.

Externally the hub 12 also has a ring gear 16 comprising convex or crowned teeth (see Figure 2) and a curvilinear, preferably circular, longitudinal axis.

The tooth arrangements 4 and 16 of the two hubs 3 and 12, which is in the universal joint described are the driving and driven members respectively, mesh with a tooth arrangement 17 on the inner face or side of a sleeve 18. The sides 19 of the teeth in this tooth arrangement are flat, as shown in Figure 2. The tooth arrangement 17 is divided into two parts or sections by an annular groove, in which a resilient ring 20 is inserted for limiting the axial movement or displacement of the sleeve 18 and for maintaining the latter on the bisecting line of the angle between the two axes.

The other end of the connecting shaft 13 is operatively connected to the pin 2 through a universal joint F which differs from that described above by the omission of the compression spring 15 and the pusher 14 and in that the extension 11 (designated by 11 in the universal joint F) is provided on the shaft 13. In connection with the identical function of the two universal joints, the same or corresponding parts are designated by the same reference numerals, but in the case of universal joint F the reference numerals are qualified by the suffix "M".

The hub 3 is driven by the pin 1 and drives the sleeve 18 through the gear pair4 and 17. The provision of the convex or crowned tooth arrangement allows an angular misalignment a between the axis 6 of the hub 3 and the axis of sleeve 18. The latter drives the hub 12 through the gear pair 16 and 17.

Also in this case, the provision of the convex or crowned tooth arrangement allows on angular misalignment a between the axis of the sleeve 18 and the axis B of the shaft 13. Accordingly, the angular misalignment between axes 6 and 13 is 2 a. Should the angular misalignment provided by the joint F be of the same sign as the former, the angular mis alignment between the axis of the hub 3M and the axis 6 would be 4 . On the other hand, should the misalignment provided by the joint F be of opposite sign, then the axes of the hubs 3 and 3M would be parallel with each other, but misalignment by an amount H which is 1 to 2 a, wherein 1 is the distance or spacing between the centres of the two ball joints when the axes of hubs 3 and 3M are coincident.

Therefore, with a solution as proposed by the invention, a drive can be provided between two highly misaligned axes or axes parallel with each other.

For a given torque to be transmitted, the improved universal joints according to the invention are also more compact than conventional universal joints, which enables them easily to solve the drive problem, also in cases where the space available is com paratively reduced.

Claims

1. A universal joint comprising driven and driving members interconnected by a ball joint, in which the members are torsionally connected through gear pairs, each of which comprises a tooth arrangement having flat side teeth and a tooth arrangement having convex or crowned teeth and a curvilinear, and preferably a circular, axis.

2. A universal joint according to claim 1, in which said driven and driving members have an outer rim provided with convex or crowned teeth and a cur vilinearaxis meshing with an inner flat side tooth arrangement relating to a sleeve.

3. A universal joint according to any of the preceding claims, in which the sleeve tooth arrange ments form part of a single interrupted or cut off tooth arrangementforthe insertion therein of an annular spacer which is effective to limit the angular amplitude of movement of the convex or crowned rims of the tooth arrangements.

4. A universal joint according to any of the preceding claims, in which said driven member is torsionally integral with a shaft, but is axially slidable relatively thereto, and is resiliently loaded so as to retain the ball connection with said driving member.

5. A universal joint substantially as described herein with reference to and as illustrated in the accompanying drawings.