ROULEMENT A PISTES CROISEES

CROSS-LINEAR BEARING UNIT

Abrégé anglais

CROSS-LINEAR BEARING UNIT
Abstract of the Disclosure
A cross-linear bearing unit comprising of: a bearing body
having on its one surface a raceway which forms a load track and
a return track and is adapted to fit a race bar therein, said
bearing body further having a rail hole which forms a load track
and a return track and is adapted to fit a rail therein, said
rail hole piercing through the bearing body in the direction
orthogonal with the raceway; balls inserted in said load track
and return track; a retainer disposed in the raceway of the
bearing body and serving to hold, out of the balls inserted in
the groove of the raceway, the loaded balls in the manner that
said balls are rolled while being kept in contact with both the
load track surface of the bearing body and the load track
surface of the race bar, said retainer also serving to hold the
nonloaded balls in the manner that said balls are rolled freely
in the return track of the bearing body; and another retainer
disposed in the rail hole of the bearing body and serving to
hold, out of balls inserted in the groove of said rail hole,
the loaded balls in the manner that said balls are rolled while
being kept in contact with both the load track surface of the
bearing body and the load track surface of the rail, said
retainer also serving to hold the nonloaded balls in the manner
that said balls are rolled freely in the return track of the
bearing body: wherein the rails are mounted on a bed horizon-
tally or vertically through bearings respectively, and a slide
base is attached to the race bars orthogonal with the rails.
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Revendications

CLAIMS:
1. A cross-linear bearing arrangement for supporting
and slide-moving a heavy load in two orthogonal directions,
comprising: a) a flat bed for supporting the bearing arrange-
ment and the load thereon; b) first and second parallel rails
supported over said bed by bearing members; c) first, second,
third and fourth bearing bodies extending outward and perpen-
dicular to said flat bed, each said bearing body having an
outer end, and said bearing bodies respectively having a
first, second, third and fourth rail hole extending through
an inner portion thereof, said first rail passing through
said first and second rail holes, said second rail passing
through said third and fourth rail holes, said rail holes
having grooves therein and defining a load track and a return
track in each said rail hole; d) first bearing balls disposed
in said grooves; e) an annular retainer disposed in each of
said rail holes serving to hold, from out of said balls
certain balls as loaded balls which are rolled while being
kept in contact with both the load track of said bearing
body and a load track surface of said rail, said retainer
also serving to hold non-loaded balls so that said balls
roll freely in said return track of said bearing body; f)
first, second, third and fourth open raceways defined at
the outer ends of each of said bearing bodies; g) first
and second parallel race bars, said first race bar being
disposed in said first and third raceways, said second race
bar being disposed in said second and fourth raceways; h)
loaded guide grooves of substantially U-shape configuration
in each said raceway and unloaded guide grooves adjacent

each of said loaded guide grooves defining a load track
and a return track, respectively; i) second bearing balls
held in each said raceway and a U-shaped retainer means in
each said raceway for holding said second bearing balls,
said retainer means serving to select, from among said
second bearing balls in said raceway, loaded balls, which
are kept in contact with both the load track of said
bearing body and a load track surface of said race bar and
also serving to hold unloaded ones of said second bearing
balls to roll freely in said return track of said bearing
body; and j) a flat slide back mounted on said first and
second race bars.

Description

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Back round of the Invention
g _ . _ .
Field of the Inv ntion:
The present invention relates to a bearing which is
adapted for use at an intersection of a column and a cross rail
in a machine tool such as boring or planing machine or at an
intersection of vertical and horizontal shafts in a general
conveyor so as to support and slide a heavy-weight object, and
more particularly it relates to a cross-linear bearing unit
capable of achieving accurate positioning of a slide member by
linearly moving the same in bc,th vertical and horizontal ~
directions. ~ -
Description of the Prior Art:
,
A tool rest disposed on a column and a cross rail in a
machine tool generally receives, during a machining operation,
great forces exerted in floating, downward and horizontal
directions in addition to the extremely large weight of its own. -
Since such forces are exerted at a point spaced apart from the
tool rest plate, a great floating load is applied to the column
shaft. merefore, it has been customary heretofore to use a
slide guide surface in the guide region for elimination of the
resultant problem. In the case of a rolling guide, a large-
diameter column shaft is employed with a bearing of a correspond _
i`ng large load capacity such as described in the U. S. Patent
3,003,828 or 3,341,262. However, incorporating the bearing of
this type into a machine causes an increase in the production
~` cost due to the necessity of using an expensive hardened steel
plate, and moreover it is extremely difficult to attain a high
accuracy particularly in the case where a plurality of such
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bearings are disposed at horizontal and vertical positions.
Summa and Ob ect of the Invention
It is an object of an aspect of the present invention
to provide a cross-linear bearing unit which is capable of
achieving accurate positioning of a slide member mounted on
a race bar by linearly moving the slide member in both
vertical and horizontal directions, wherein the load-carry-
ing capacity of a bearing body is increased, and the space
between the race bar and a rail fitted respectively into
a raceway and a rail hole can be minimized.
In accordance with one aspect of this invention there
is provided a cross-linear bearing arrangement for support-
ing and slide-moving a heavy load in two orthogonal
directions, comprising: a) a flat bed for supporting the
bearing arrangement and the load thereon; b) first and
second parallel rails supported over said bed by bearing
members; c) first, second, third and fourth bearing bodies
extending outward and perpendicular to said flat bed, each
said bearing body having an outer end and said bearing
bodies respectively having a first, second, third and
fourth rail hole extending through an inner portion thereof,
said first rail passing through said first and second rail
holes, said second rail passing through said third and
fourth rail holes, said rail holes having grooves therein
- and defining a load track and a return track in each said
rail hole; d) first bearing balls disposed in said grooves;
e) an annular retainer disposed in each of said rail holes
serving to hold, from out of said balls certain b~lls as
loaded balls which are rolled while being kept in contact
with both the load track of said bearing body and a load
track surface of said rail, said retainer also serving to
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1086807
hold non-loaded balls so that said ~alls roll freely in said
return track of said bearing body; f) first, second, third
and fourth open raceways defined at the outer ends of each
of said bearing bodies; g) first and second parallel race
bars, said first race bar being disposed in said first and
third raceways, said second race bar being disposed in said
second and fourth raceways; h) loaded guide grooves of sub-
stantially U-shape configuration in each said raceway and
unloaded guide grooves adjacent each of ~aid loaded guide
grooves defining a load track and a return track, respective-
ly; i) second bearing balls held in each said raceway and a
U-shaped re~ainer means in each said raceway for holding
said second bearing balls, said retainer means serving to
select, from among said second bearing balls in said raceway,load-
ed balls, which are kept in contact with both the load track
of said bearing body and a load track surface of said race
bar and also serving to hold unloaded ones of said second ~-
bearing balls to roll freely in said return track-of said
bearing body; and j) a flat ~ide back mounted on said first
and second race bars.
B ief Description of the Drawings
Fig. 1 is a partially cutaway front view of a cross-
linear bearing unit according to the present invention; Fig.
2 is a sectional view taken along the line II-II in Fig. l;
and Fig. 3 is a perspective view illustrating how the bear-
ing unit of Fig. 1 is employed.
Detailed Describtion of the Invention
Hereinafter an exemplary embodiment of the present
invention will be described in detail with reference to the
30 accompanying drawings. .
As shown in Figs. 1 and 2, a raceway 3 where a race bar 2
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807
is fittable is formed on one side of a bearing body 1, and a
rail hole 13 where a rail 12 is fittable is formed in the
manner to pierce through the bearinq body 1 in the direction
orthogonal with the raceway 3.
The raceway 3 in the bearing body 1 is equipped with
loaded-ball guide grooves 7, 7 having a substantially U-shaped
cross section and constituting a load track where loaded balls
Sa, 5a are rollable in two rows, a nonloaded-ball guide grooves
8 formed between the guide grooves 7, 7 and having a substantia-
lly U-shaped cross section and constituting a return track
where nonloaded balls 5b, 5b are rollable in two rows, and
grooves formed outside of the guide grooves 7, 7 and constitut-
ing a return track where the nonloaded balls 5b are rollable
in one row. The ends of the load-track grooves 7, 7 are
connected respectively to the adjacent nonloaded-track grooves
8, 8, 8 so as to permit circulation of the balls.
The cross-sectional shape of the race bar 2 fittable into
the raceway 3 in the bearing body 1 is uniform over the entire
length and is symmetrical with respect to its left and right.
On shoulders 4, 4 of the race bar 2, rolling grooves 6, 6 for
the loaded balls Sa, 5a are formed in the longitudinal direction
at positions opposite to the nonloaded-track grooves 7, 7 of
the raceway 3 in the bearing body 1, thereby constituting a
rolling path for the loaded balls 5a, 5a through mutual
cooperation. Along two sides of the race bar 2, recesses 11,
11 are formed in the longitudinal direction thereof correspond-
ingly to the grooves 8, 8 which constitute the return track in
the bearing body 1.
The balls are held in the raceway 3 of the bearing body 1
~¦by a reta ner 9 in such a manner that the loaded balls Sa, Sa
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, .. re rolled into the retllrn-track grooves 8, ~, 8 while being~
kept in contact with the guide groov~s 7, 7 constituting the
load track in the bearing body 1 and also with the rolling
grooves 6, 6 .... formed in the race bar 2, meantime the
unloaded balls 5b, 5b ... are rolled freely in the return-
track grooves 8, 8, 8 of the bearing body 1 and are returned
smoothly into the load-track grooves 7, 7.
The rail hole 13 formed in the bearing body 1 is equipped
with loaded-ball guide grooves 17, 17, 17 having a substantially
U-shaped cross section with a relatively small depth from the
inner-diameter surface thereof and constituting a load track
where loaded balls 15a, 15a are rollable in two rows, and
nonloaded-ball guide grooves 18, 18, 18 having a substantially
U-shaped cross section with a larger width and a relatively
small depth from the inner-diameter surface and constituting
a return track where nonloaded balls 15b, 15b are rollable in
two rows. ~he bol:h guide grooves are arrayed alternately in the
axial direction, and the ends of the load-track guide grooves
17, 17, 17 are connected respectively to the adjacent nonloaded-
track guide grooves 18, 18, 18 so as to permit circulation of
the balls.
The rail 12 fittable into the rail hole 13 in the bearing
body 1 serves also as a spline shaft, whose cross-sectional
shape is uniform over the entire length and is substantially
triangular with swells and protrusions 23, 24, 25. And the
two sides of each vertex of the triangle, rolling grooves 16,
16 for the loaded balls 15a, 15a are formed in the longitudinal
direction thereof at positions opposite to the load-track guide
groove 17 of the rail hole 13 in the bearing body 1, thereby
constituting a rolling path for the loaded balls 15a, 15a
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10868117
through mutual cooperation.
The balls a~e held in the rail hole 13 of the bearing body
1 by a retainer 19 in such a manner that the loaded balls lSa,
. 15a ..... are rolled into the return-track guide grooves 18,
.~ 5 18, 18 while being kept in contact with the guide grooves 17,
,,, 17, 17 constituting the load track in the bearing body 1 and
also with the rolling grooves 16, 16 ...... formed in the rail
12, meantime the unloaded balls 15b, 15b are rolled freely in
the return-track guide grooves 18, 18, 18 of the bearing body
1 and are returned smoothly into the load-track guide grooves
17, 17, 17.
. Thus~ the above-described embodiment of cross-linear
bearing unit is so constructed as to be able to support a
tensile load applied in the direction where the bearing body 1
separates from the race bar 2. In Fig. 3 showing an example
, of using four bearing bodies 1, 1, 1, 1, two of them are
mounted on each of two parallel rails 12, 12 provided on a bed
~, 20, and two parallel race bars 2, 2 are fitted into the bearing
~, bodies 1, 1, 1, 1 with a slide base 21 attached fixedly to the :~
race bars 2, 2 so as to be slid vertically and horizontally.
. And when the slide base 21 is slid leftward or rightward, a :~:
pressure load is applied to the bearing bodies 1, 1 located on
one rail 12, while a tensile load is applied to the bearing
bodies 1, 1 on the other rail 12. In this case, each bearing
body 1 is capable of supporting with certainty the load
resulting from the slide base 21, hence offering a remarkably
wi~e scope of application and great conveniences in practical
~ j use.
:~ ¦ It is to be understood that the cross-linear bearing unit
~, 30 ¦ of the present invention is not restricted merely to the
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108~;8~7
aforementioned embodiment and exemplary use illustrated where
the positions of the raceway and the rail hole are orthogonal
with each other, and the intersection angle thereof is selecta-
' ble as desired. In this case, the intersection angle of the
.;~ race bar and the rail is determined in accordance with that of
:~ the raceway and the rail hole formed in the bearing body.
,. Furthermore, it is also possible to incline either the
, raceway or the rail hole in the bearing body along its
longitudinal direction and to position the slide base along the
1- inclined s~ face.
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