GB2040019A

GB2040019A - Noise resistant universal joint

Info

Publication number: GB2040019A
Application number: GB7942706A
Authority: GB
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1978-12-11
Filing date: 1979-12-11
Publication date: 1980-08-20
Also published as: FR2444193B1; JPS5586128U; DE2949772C2; JPS5942502Y2; FR2444193A1; GB2040019B; DE2949772A1

Description

1 GB 2 040 019 A 1

SPECIFICATION

A noise resistant universal joint The present invention relates to a universal joint for connecting a pair of shafts, and more especially to a universal joint suitable for the connection of a vehicle steering wheel shaft to a power steering gearbox shaft.

Figure 1 of the accompanying drawings shows a previously known motor vehicle steering mechanism. A universal joint 10 connects a steering shaft 12 to the input shaft 14 of a power steering gearbox 16. A pair of shoes 18 are slidably received in opposite grooves 20 provided on the inner surface of a cup-like housing 22 and extending in the axial direction of the housing. These shoes 18 are loosely received on the opposite protruding end portions of a cross pin 24 supported by and projecting from both sides of the end portion of the steering'shaft 12 which extends through a jacket tube 26 and is secured at the other end to a steering wheel 28. A sleeve 30 extending axially outwards from the bottom of housing 22 receives the input shaft 14 through a spline connection. Reference numeral 32 denotes a mounting plate for mounting the jacket tube 26 in a motor vehicle (not shown).

When a motor vehicle with a power steering gearbox is steered, vibrations of fluid noises will generally be generated in the power steering gearbox by the reduction of the opening of the valves therein when the steering torque is lower than a certain value. These noises are passed directly to the housing 22 and thence through the shoes 18, the cross pin 24, and the shaft 12 to the steering wheel 28 thereby vibrating the same and creating a noise nuisance.

It is an object of the present invention to provide a universal joint which prevents the transmission of noise vibrations between two shafts.

Another object of the present invention is to provide a universal joint which prevents the transmission of noise vibrations created in a power steering gearbox to a steering wheel.

Still another object of the present invention is to provide a universal joint in which steering torque is positively transmitted from a steering wheel to a power steering gearbox.

The invention provides a universal joint compris ing; an open-ended hollow housing of substantially 115 cylindrical shape in which are formed a pair of axially extending shoe grooves; a first shaft having an end portion inserted into the housing through one end thereof; a cross pin supported by the said end portion of the first shaft so as to project from its 120 opposite sides; a pair of shoes supported by the end portions of the cross pin and engaged with the shoe grooves; a second shaft having an end portion inserted into the housing through the other end thereof; and a noise vibration absorbing member of 125 a resilient material disposed between the said end portion of the second shaft and the housing for preventing the transmission of noise vibrations between the second shaft and the housing.

The invention also provides a steering mechanism 130 for a motor vehicle, including a steering wheel shaft connected to the input of a power steering gearbox by a universal joint according to the invention.

The invention further provides a motor vehicle fitted with a steering mechanism according to the invention.

One form of steering mechanism constructed in accordance with the invention will now be described by way of example with reference to the accompany- ing drawings, in which:

Figure 1 is a side view of a prior art motor vehicle steering mechanism, showing its universal joint in cross-sectional view;

Figure2 is a side view of part of a motor vehicle steering mechanism according to the present invention, partly in axial cross-sectional view; Figure 3 is a cross-sectional view taken along the line 111-111 in Figure 2; and Figure 4 is an exploded view of the universal joint.

Referring to Figure 2 of the accompanying drawings, there is shown a motor vehicle steering mechanism embodying the present invention. A jacket tube 40 is connected at one end to an inwardly turned end portion 42a of a hollow substantially cylindrical dust boot 42 whose other end portion is provided with an outer circumferential recess 42b which receives the inner edge of a hold 44a in a raised flat end face of a mounting base 44, which is arranged to be mounted to the body of the vehicle, not shown, by bolts 46. A cup-shaped retainer 48 is provided at its bottom with an opening 48a through which an intermediate shaft 50 extends coaxially and an outwardly bent edge portion 48b which secures the end portion of the boot 42 to the inner edge of the hole 44a. The jacket 40 and the retainer 48 co-operate to support the intermediate shaft 50 rotatably by a bearing 53 provided between the jacket tube 40 and the shaft 50. The shaft 50 is then connected at one end by a spline portion 50b to one end of a steering wheel shaft 52 which passes through the jacket tube 40 and has a steering wheel (not shown) attached to its other end. The other end portion 50c of the intermediate shaft 50 extends into a hollow cylindrical housing 54 of a universal joint 56 through one open end thereof and supports a cross pin 58 which projects transversely in radial directions. A pair of shoes 60 are slidably fitted over the projecting portions of the cross pin 58 and received in a pair of opposed grooves 54a provided in the inner surface of the housing 54 and extending in the axial direction thereof so that the shoes 60 may slide along the grooves. The shoes 60 are resiliently pressed against the bottoms of the grooves 54a by a substantially U-shaped resilient member 62 which is fitted over the end portion of the shaft 50 and the legs 62a of which are each bifurcate so as to engage the opposite projecting portions of the cross pin 58. A snap ring 64 is fitted over the shaft 50 within the housing 54 nearthe righthand end of the housing, as seen in the Figure 2, in orderto prevent the shoes from slipping out of the housing axially. Reference numeral 66 denotes a dust boot provided between the housing 54 and a groove 50a in the shaft 50 for protection against dust. The housing 54 is provided with an enlarged inner open end 54b, in which a 2 GB 2 040 019 A 2 collar 68 is force fitted, and is then reduced at its end portion 54c to secure the collar. Bonded to the inside the collar 68 is an annular noise vibration absorbing member 70 of a resilient material such as rubber within which one end portion of a connecting member 72 is inserted and bonded thereto, and the other end portion of connecting member 72 is joined at a splined portion 72a (see Figure 4) to an input shaft 74 of a power steering gearbox 76.

As will be seen from Figures 3 and 4, the connecting member 72 is split at a portion 72b as shown in Figure 4. When the input shaft 74 of the power steering gearbox 76 is inserted in the connect ing member 72, this member 72 is clamped tightly to the shaft 74 by tightening a bolt 78 in a threaded hole 80 72cformed in the connecting member 72. The connecting member 72 is provided at the opposite end from the splined portion with a pair of pegs 72d projecting axially outwards at radially opposite portions and received loosely in corresponding grooves 54d provided in the inner surface of the housing 54 at points circumferentially midway be tween the shoe grooves 54a and extending in the axial direction of the housing so as to form an appropriate spacing 1 between each of the circum ferential end faces of the pegs 72d and the adjacent circumferential end face of a corresponding groove 54d. Reference numeral 80 denotes a grease leakage prevention cap fitted into the opening in the connect ing member 72 in order to prevent grease within the housing 54 from leaking out from inside through the splined portion 72a.

In operation, when a small torque is applied to the steering wheel, the shafts 52 and 50 are rotated along with the cross pin 58 and the shoes 60. This causes the housing 54 to rotate thereby imparting the torque through the vibration absorbing member 70, the connecting member 72 and the shaft 74.

When the torque is smaller than a certain value, fluid noises will be generated in power steering gearbox 76 due to the reduction of the opening of the valves (not shown) provided therein. However, these fluid noises will be absorbed by the vibration absorbing member 70 and not transmitted through the shafts 50 and 52 to the steering wheel.

When the steering torque increases beyond a certain value, the resilient noise vibration absorbing member 70 is deformed sufficiently that each peg 72d of the connecting member 72 directly engages against a face of the corresponding groove 54d.

Thus the higher torque is transferred with substan tially no loss from the housing 54 to the connecting member 72. In this case, however, because of the higher torque, the pumps (not shown) provided in the power steering gearbox will be in their relief range, with the result that no fluid noises are generated, so that again the driver and passengers of a motor vehicle are not disturbed by noises transmitted to the steering wheel.

It will be seen from the above that by the present invention, a universal joint can be provided which prevents, or at least reduces, the passage of noise vibration at low torques, and yet also transmits a high torque efficiently.

Claims

1. A universal joint comprising; an open-ended hollow housing of substantially cylindrical shape in which are formed a pair of axially extending shoe grooves; a first shaft having an end portion inserted into the housing through one end thereof; a cross pin supported by the said end portion of the first shaft so as to project from its opposite sides; a pair of shoes supported by the end portions of the cross pin and engaged with the shoe grooves; a second shaft having an end portion inserted into the housing through the other end thereof; and a noise vibration absorbing member of a resilient material disposed between the said end portion of the second shaft and the housing for preventing the transmission of noise vibrations between the second shaft and the housing.

2. A universal joint as claimed in claim 1, where- in the noise vibration absorbing member is of annular shape.

3. A universal joint as claimed in claim 1 or claim 2, wherein the said other end of the housing is provided with an enlarged opening, the joint further including a collar force fitted within the enlarged opening and the noise vibration absorbing member being fitted within the collar.

4. A universal joint as claimed in anyone of claims 1 to 3, wherein the housing further has a pair of axially extending peg grooves, and the second shaft has a pair of axially extending pegs fitted loosely within the peg grooves whereby, when a torque of more than a certain value is applied to the joint, the peg grooves and corresponding pegs, respectively, are directly engaged circumferentially.

5. A universal joint as claimed in claim 4, wherein the pegs are provided at the end of the second shaft that is inserted into the housing.

6. A universal joint as claimed in claim 4 or claim 5, wherein the peg grooves are disposed substantially circumferentially midway between the shoe grooves.

7. A universal joint substantially as hereinbefore described with reference to, and as shown in, Figures 2 to 4 of the accompanying drawings.

8. A steering mechanism fora motor vehicle, including a steering wheel shaft connected to the input of a power steering gearbox by a universal joint as claimed in any one of claims 1 to 7.

9. A motor vehicle fitted with a steering mechanism as claimed in claim 8.

Printed for Her Majesty's Stationery Office by Croydon Printing Company Limited, Croydon Surrey, 1980. Published bythe Patent Office,25 Southampton Buildings, London,WC2A lAY, from which copies may be obtained.

1 1 1 Y