FR2506868A1 - Ball and socket coupling - has chromium plated outer housing and bronze, spherical inner ball to reduce friction - Google Patents

Abstract

The spherical rotary joint comprises an outer housing (1) with a spherical bore. The surface of the spherical bore is plated in hard chromium. Two slots (4) are provided for the introduction of the rotary element (2). The rotary element is manufactured from bronze and the combination of the hard chromium plating and the bronze inner element ensures a low coefficient of friction.

Description

The present invention relates to a perfection
in the method of manufacturing the ball joints.

We know that such a mechanical component is general
ment consisting of a sphere truncated in two planes
parallel and pierced so as to appear under the forum
me of an externally spherical ring on which is
mounted a second internally spherical ring matching
intimately the first.

your two rings are generally subject to
oscillations and combined rotations that cause a
rapid seizure of spherical surfaces when they are
made of steel.

To decrease the coefficient of friction, we have
used the steel-bronze combination, the inner ring
being in bronze and the outer one in steel.

Knowing moreover the good results in this
which concerns the reduction of friction resulting from
the use of chromium plating, we made ball joints whose 'inner ring was chromed. However, the results
that you would expect from chrome plating weren't satisfied
doing with regard to the longevity of the component.

The present invention, which overcomes this drawback,
is remarkable in that it is the inner surface
spherical outer ring which is chrome.

In the attached drawing as an indicative example
only, Figure 1 is an elevational view of the ro
tule of the invention
Figure 2 is a sectional view taken along the
line II-II of Figure 1;
Figure 3 is a sectional view taken along the
line III-III of Figure 1 limited to the outer ring.

Referring to the drawing, we see that, in the way
known, the ball joint is composed of two rings 1 and 2.

The inner ring 2 is formed from a
sphere bored in 3 and truncated in two parallel planes
and perpendicular to the axis of the bore.

 The outer ring 1 has at its center a spherical cavity which can receive, without play, the ring 2.

 In known manner, the ring 1 has two notches 4, diametrically opposite, allowing the positioning of the ring 2 in that 1 by a transverse engagement followed by a rotation of 900.

 According to the present invention, the spherical inner surface of the ring 1 is covered with a layer 5 of hard chromium according to a known technique.

 Experience has shown that the combination of an inner bronze ring and an outer ring with a chrome surface makes it possible to obtain a ball joint having excellent behavior when it is subjected to combined movements of oscillation and , or, rotation.

it has in particular been noted that it is possible with such a ball joint to increase the contact pressure between the two spherical surfaces without altering the longevity of the ball joint.

 This result is all the more surprising since in the current state of the art, the use of chromium plating had not brought appreciable results and had been abandoned because it was useless to increase the cost price of the ball joint. if it should not have superior qualities as has been found.

Claims (2)

 1- Ball joint of the kind formed by two rings (1 and 2) engaged one inside the other according to a spherical contact surface, characterized in that the spherical inner surface of the outer ring is covered with a layer ( 5) hard chrome.  2- ball joint according to claim 1, characterized in that the inner ring (2) is bronze.