Bearings – Linear bearing – Lubricating
Reexamination Certificate
2000-12-06
2003-02-11
Footland, Lenard A. (Department: 3682)
Bearings
Linear bearing
Lubricating
C384S045000
Reexamination Certificate
active
06517244
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a linear motion guide unit comprised of an elongated track rail and a slider installed onto the track rail for linear movement relative to the track rail and, more particularly, to a linear motion guide unit with lubricating means to apply lubricant to the track rail as the slider traverses the rail.
2. Description of the Prior Art
The linear motion guide units have been conventionally used incorporated in the parts or components for reciprocating motion in fields as diverse as the industrial robots, semiconductor manufacturing machines, inspection instruments, machine tools or the like to satisfy the demands for higher accuracy, high-speed, miniaturization and so on. The recently remarkable development in mechatronics technology extensively requires linear motion guide units that may meet with needs of maintenance-free, especially, the self-lubrication of long service life on its relatively movable sliding areas, along with miniaturization, higher accuracy and high-speed in operation.
FIGS. 17
to
19
in the accompanying drawings show a prior linear motion guide unit disclosed in, for example, Japanese Patent Laid-Open No. 93952/1999. The prior linear motion guide unit is primarily comprised of a track rail
2
and a carriage or slider
1
riding the track rail
2
astride for sliding movement. The track rail
2
is formed in a substantially rectangular shape in cross section, which are recessed on lengthwise side surfaces
3
thereof to provide raceway grooves
4
. The slider
1
may move on the track rail
2
by virtue of rolling elements running through the raceway groove
4
. The slider
1
includes a casing
5
recessed so as to fit over the track rail
2
for sliding movement with respect to the track rail
2
, and end caps
6
mounted to forward and aft ends of the casing
5
, one to each end.
The casing
5
is made with raceway grooves
9
in opposition to the raceway grooves
4
on the track rail
2
to allow rolling elements
7
to run through between the confronting raceway grooves
4
and
9
. Retainer bands
18
are provided in the casing
5
so as to embrace the rolling elements
7
to thereby prevent the rolling elements
7
from falling out of the casing
5
. Bottom seals
8
are attached to the lower surfaces of the casing
5
and the end caps
6
to close clearances between the track rail
2
and the combined casing
5
and end caps
6
. The rolling elements
7
run through load areas of raceways defined between the raceway grooves
4
on the track rail
2
and the raceway grooves
9
in the casing
5
, then turnarounds formed in the end caps
6
and return passages
12
formed in parallel with the raceway grooves
9
in the casing
5
. It will be thus understood that the rolling elements
7
are allowed to run through recirculating passages, each of which consists of the load area of the raceway defined between the confronting raceway grooves
4
and
9
, and non-loaded area
22
composed of the turnarounds and return passages
12
. The slider
1
is allowed to move in a sliding manner along the track rail
2
by virtue of the rolling elements
7
that roll through the load areas between the confronting raceway grooves
4
and
9
.
Lubricating means
15
are fastened to end faces
16
of the forward and aft end caps
6
, one to each end cap, so as to ride the track rail
2
astride. The lubricating means
15
are each comprised of a lubricant-impregnated plate
40
coming in sliding contact with the track rail
2
, and a backing cartridge
21
to support the lubricant-impregnated plate
40
therein. Each lubricating means
15
is made in a platy configuration of uniform thickness and recessed in conformity with the cross section of the casing
5
so as to fit over and conform to the track rail
2
for sliding movement. The backing cartridge
21
has the contour substantially resembling a gate as a whole, which is composed of a ceiling section
28
, a pair of side sections
29
,
29
extending downward from the sidewise opposing ends of the ceiling section
28
, and lower sections
30
,
30
extending towards each other from the bottom ends of the side sections
29
,
29
.
Each lubricating means
15
may fit over the track rail
2
with its ceiling section
28
lying in parallel with a top surface
14
of the track rail
2
, the side sections
29
,
29
depending downwards in parallel with the lengthwise side surfaces
3
of the track rail
2
, and its lower sections
30
,
30
extending towards the lengthwise side surfaces
3
of the track rail
2
. Thus, the backing cartridge
21
holds in place the lubricant-impregnated plate
40
by surrounding around the periphery of the lubricant-impregnated plate
40
, except areas facing the track rail
2
. The lubricant-impregnated plate
40
is uncovered at its fore-and-aft major surfaces: forward and aft end surfaces facing against the end caps
6
and end seals
17
respectively. Thus, the lubricant-impregnated plate
40
is left exposed at its major end surfaces until covered with its associated end cap
6
and end seal
17
on the slider
1
. The backing cartridge
21
conceals the periphery of the lubricant-impregnated plate
40
to seal pores in the porous structure, protecting the lubricant-impregnated plate
40
against contamination, breakage and escape of lubricant.
The backing cartridge
21
, although may be made of any one of metals, synthetic resins, synthetic rubbers and so on, is invariably made of any substance that may be much subject to either elastic deformation or plastic deformation restorable later in order to provide an easy to replace or handle the lubricating means
15
. Where the lubricant-impregnated plate
40
is fitted in the backing cartridge
21
, or only the lubricating means
15
is either mounted to or dismounted from the track rail
2
with all the casing
5
, end caps
6
and end seals
17
left on the track rail
25
, the backing cartridge
21
that may be easily subject to either plastic or elastic deformation without occurring breakage makes it possible to simply fit the lubricant-impregnated plate
40
into the backing cartridge
21
or mount the lubricating means
15
on the track rail
2
.
The lubricating means
15
will be attached to the casing
5
with the backing cartridge
21
being urged against the end faces of the end caps
6
fastened on the forward and aft ends of the casing
5
, thence the backing cartridge
21
is reinforced at its four corners
22
where holes
24
are made for fastening bolts
25
. The end caps
6
and end seals
17
sandwiching the backing cartridge
21
between them are also made with matching holes
26
,
27
for the fastening bolts in alignment with the holes
24
in the backing cartridge
21
. Thus, the backing cartridge
21
, together with the associated end cap
6
and end seal
17
keeping the backing cartridge
21
between them, is held on the slider
1
with the fastening bolts
25
, which are stretched through the holes
26
,
24
and
27
in the end cap
6
, backing cartridge
21
and end seal
17
, and ultimately screwed into holes in the casing
5
of the slider
1
. With the backing cartridge
21
made of synthetic resin or synthetic rubber, collars
23
fit in holes
24
in such a manner that the collars
23
mostly sustain the squeezing force applied by the fastening bolts
25
, which are inserted through the collars
23
and tightened, to thereby protect the backing cartridge
21
against the deformation or distortion that might otherwise happen due to the compressive force when tightened.
The lubricant-impregnated plate
40
, as shown in
FIG. 19
, is divided into lubricant-impregnated halves
41
,
41
, which are arranged on opposite sides of the track rail
2
so as to separately come in sliding contact with their associated raceway grooves
4
on the track rail
2
. The lubricant-impregnated halves
41
,
41
, assembled in the backing cartridge
21
, are arranged spaced apart from one another with a middle area
33
in the backing car
Browdy and Neimark
Footland Lenard A.
Nippon Thompson Co. Ltd.
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