Bearings – Linear bearing – Recirculating
Reexamination Certificate
1994-11-29
2001-05-15
Footland, Lenard A. (Department: 3682)
Bearings
Linear bearing
Recirculating
C029S898030
Reexamination Certificate
active
06231238
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a linear movement guide apparatus, which is used to be applied to linear guide portions of, for instance, machine tools or robots for use in industrial purpose.
In such machine tools or robots, all kinds of load, i.e. load from a radial direction, load from a horizontal direction, load from a reversed-radial direction, and a moment load, are applied to the linear guide portion thereof, since the linear guide portion of the tools or robots is diversified. The present invention, particularly, relates to a linear movement guide apparatus and a method for assembling the apparatus, in which a common member is used to manufacture a tracking base and a sliding base of the apparatus without regard to the amount or the direction of load applied thereto, and suitable contact angles according to the directions, to which the loads are applied, can be obtained to give a maximum life time, a maximum stiffness and a maximum allowance of load to the apparatus.
BACKGROUND ART
First Prior Art
Such kind of linear movement guide apparatus is, for instance, disclosed in Japanese Utility Model Preliminarily Publication No. Hei 3-199710.
FIG. 23
is a schematic view showing an apparatus of the first prior art.
As shown in
FIG. 23
, the linear movement guide apparatus
30
comprises a tracking base
31
having a square-shape cross-section, a sliding base
32
having a concave portion
32
, which also has a square-shaped cross section, for accepting said tracking base
31
, and four rows of indefinitely circulating balls
33
. On an upper surface of the tracking base
31
are provided two rows of ball rolling grooves
31
a
, and on each side surface of the tracking base
31
is arranged one row of ball rolling groove
31
b
, respectively. On an inside surface of said concave portion
32
c
of said sliding base
32
, are provided two rows of corresponding ball rolling grooves
32
a
so as to face to said two rows of ball rolling grooves
31
a
formed on the upper surface of the tracking base
31
, and one row of corresponding ball rolling groove
32
b
formed on each side surface thereof so as to face to the row of ball rolling groove
31
b
formed on the upper surface of the tracking base
31
, respectively. The ball rolling grooves
31
a
and
32
a
, which face to each other, are arranged as circular-ark shaped shallow grooves having a slightly larger dimension than that of the balls to be held therein. It should be noted that the ball rolling grooves
31
a
and
31
b
, which also face to each other, are arranged as Gothic ark-shaped grooves.
Holders
34
and
35
are provided in the apparatus in order to prevent that balls
33
are fallen down from the grooves when the sliding base
31
is taken off from the tracking base
32
.
Contact angles of balls, in the linear movement guide apparatus
30
, are arranged such that the contact angles in the upper two ball rows are substantially directed in a vertical direction, but in the lower two ball rows, the balls are made contact with the ball rolling grooves, which have their shapes of a combination of two circular-arks, at four points, i.e. at perspective upper points and perspective lower points, in a substantially even manner (hereinafter, such contact condition is called “complete four points contact”). In such a manner, above, in the linear movement guide apparatus
30
, the load applied from an upper direction is supported by the two rows of ball rolling grooves
31
a
and
32
a
having circular-ark shapes; and the load applied from a horizontal direction is supported by the ball rolling grooves
31
b
and
32
b
having Gothic-ark shapes by the complete four points contact.
Therefore, the apparatus has an excellent load supporting capability against the loads applied from not only an upper direction but also a lateral direction.
Second Prior Art
On the other hand, another linear movement guide apparatus
40
is disclosed in Japanese Utility Model Publication no. Sho 63-24258.
As shown in
FIG. 24
, the linear movement guide apparatus
40
comprises a tracking base
41
having a square-shaped cross section, a sliding base
42
having a concave portion
42
c
, which also has a square-shaped cross section, for accepting the tracking base
41
, and four rows of infinite circulating balls
43
.
On side surfaces of the tracking base
41
are provided two rows of ball rolling grooves
41
a
, respectively; and on an inside surface of the concave portion
42
c
of the sliding base
42
are provided corresponding two rows of ball rolling grooves
42
a
so as to face to the ball rolling grooves
41
a
of the tracking base
42
. Therefore, four rows in total are formed in the apparatus. These ball rolling grooves
41
a and
42
a
, which face to each other, are designed as Gothic-ark shaped grooves, and the contact angle of balls in each ball row is arranged about 45 degrees with respect to a horizontal direction.
In the linear movement guide apparatus
40
, it is possible to have different constructions that the extended lines of the contact angles on the side surfaces of the tracking base
41
intersect with each other outside of the tracking base
41
(hereinafter, called as “DB structure”), or that the extended lines intersect with each other inside of the tracking base
41
(hereinafter, called as “DF structure”), by making a distance A between two rows of ball rolling grooves
41
a
and
41
a
, which are formed on the side surfaces of the tracking base
41
, larger or smaller than a distance B between the corresponding two rows of ball rolling grooves
42
a
and
42
a
, which are formed on the inside surface of the sliding base
42
.
In any way, in the linear movement guide apparatus
40
, when a small load is applied thereto from a vertical direction, the load is supported by one of the ball rows formed on the side surfaces, i.e. two ball rows in total; and when a large load is applied thereto from the vertical direction, the load is supported by two ball rows formed on the side surfaces, i.e. four ball rows in total. Since the number of ball rows for supporting the load is increased when a heavy load is applied, as stated in the above, a burden for the load in each ball rolling groove is reduced, so that the life time of the linear movement guide apparatus
40
becomes long.
Third Prior Art
Another linear movement guide apparatus, in which six ball rows in total are provided, is disclosed in, for instance, Japanese Patent Application Preliminarily Publication No. Sho 62-141308. In this apparatus, two ball rows are formed on an upper surface side of a tracking base, and two ball rows are on the right and left side surfaces thereof, respectively.
As shown in
FIG. 25
, the linear movement guide apparatus
100
comprises a tracking base
101
, a sliding base
102
having a concave portion
102
d
for accepting the tracking base
101
which is linearly guided along the tracking base
101
, and six rows of indefinite circulated balls
103
which are provided between the sliding base
102
and the tracking base
101
in a rotatable manner.
On an upper surface of the tracking base
101
, are provided a couple of ball rolling grooves
101
a
, and on each side surface thereof, are formed a couple of ball rolling grooves
101
b
and
101
c
, respectively. On the other hand, on an upper surface and each side surface of the concave portion
102
d
of the sliding base
102
, are formed corresponding ball rolling grooves
102
a
,
102
b
and
102
c
, facing to the ball rolling grooves
101
a
,
101
b
and
101
c
formed on the surface of the tracking base
101
, respectively.
In addition thereto, holders
107
and
108
are provided in the two ball rows
104
formed on the upper surface of the tracking base and in the two ball rows
105
and
106
formed on each side surface of the tracking base, respectively, in order to prevent that the balls
103
are fallen down when the sliding base
102
is taken off from the tracking base
101
.
In the linear movement guide apparatus
100
, the contact angles of balls in the ba
Armstrong, Westerman Hattori, McLeland & Naughton
Footland Lenard A.
THK Co. Ltd.
Williams C
LandOfFree
Linear movement guide apparatus and method for assembling... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Linear movement guide apparatus and method for assembling..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Linear movement guide apparatus and method for assembling... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512831