Bearings – Linear bearing – Recirculating
Reexamination Certificate
2001-03-13
2003-05-06
Schwartz, Christopher P. (Department: 3683)
Bearings
Linear bearing
Recirculating
Reexamination Certificate
active
06558038
ABSTRACT:
The present application claims priority under 35 U.S.C § 119 to Japanese Patent Application No.2000-073932 filed Mar. 13, 2000 entitled “ROLLING GUIDE DEVICE”, No.2000-367605 filed Dec. 1, 2000 entitled “ROLLING GUIDE DEVICE AND DRIVE SYSTEM USING ROLLING GUIDE DEVICE”, and No.2001-037486 filed Feb. 14, 2001 entitled “ROLLING GUIDE DEVICE AND DRIVE SYSTEM USING ROLLING GUIDE DEVICE”. The contents of that application are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rolling guide device in which a movable rail is made slidable with respect to a track rail and also relates to a drive system using such a rolling guide device.
2. Description of the Related Art
As a rolling guide device in which a movable rail is made slidable with respect to a track rail, there has been known a slide rail such as shown in
FIG. 25
(see Japanese Utility Model Publication No. SHO 62-8765). Such slide rail comprises a track rail member
1
having an opened recess
1
a
(i.e., having substantially
-shaped (box-shaped) cross section) formed by both inner side surfaces
1
b
,
1
b
and a bottom surface
1
c
and a movable rail member
2
which is supported between both the inner side surfaces
1
b
,
1
b
of the track rail member
1
to be movable in the longitudinal direction thereof. The movable rail member
2
also has an opened recess
2
a
(i.e., having substantially
-shaped (box-shaped) cross section).
The track rail member
1
and the movable rail member
2
have substantially the same longitudinal length. The inner side surfaces
1
b
of the track rail member
1
are formed with ball rolling grooves, respectively, along which balls roll in the longitudinal direction thereof, and outer side surfaces
2
b
of the movable rail member
2
are also formed with loaded ball rolling grooves, respectively, so as to extend in the longitudinal direction thereof and to oppose the ball rolling grooves formed to the track rail member
1
.
A number of balls
3
are arranged and housed between these ball rolling grooves and loaded ball rolling grooves, and these balls
3
are held by a cage
4
to be rotatable and slidable. When the movable rail member
2
slides with respect to the track rail member
1
in the longitudinal direction thereof, these balls
3
roll and, hence, the slide rail becomes smoothly expandable or contractive.
Further, though not shown, there is also known a cam-follower type drawer device of a structure that is movable and track rails are both provided with wheels so that the movable rail is drawn with respect to the track rail, as a rolling guide device in which a movable rail is slidable with respect to a track rail.
However, in the conventional slide rail such as mentioned above, a number of balls
3
disposed and arranged between the track rail member
1
and the movable rail member
2
do not completely perform the rolling motion and will roll with a slight sliding motion. In the conventional slide rail, because the balls
3
do not circulate and only reciprocally move along the loaded rolling passage between the ball rolling grooves and the loaded ball rolling grooves, if the balls
3
slide, the cage
4
supporting (bearing) the balls
3
would be displaced from the initial position. As a result, in spite of the fact that an effective stroke of the movable rail member
2
is not achieved, the cage
4
collides with a stopper
5
of the track rail member
1
and, hence, such effective stroke could not be obtained. In this case, when it is required to slide the movable rail member
2
with the cage
4
colliding with the stopper
5
, the movable rail member
2
will slide with the balls
3
being slipped, and accordingly, a large force is required to move the movable rail member
2
.
Furthermore, in the conventional structure of the slide rail, in order to obtain a large stroke of the movable rail member
2
, it is necessary for the movable rail member
2
to once come off from a portion at which the balls
3
exist and then to be engaged with that portion at which the balls
3
exist. That is, in the case where the movable rail member
2
comes off from the portion at which the balls
3
exist, for example, the movable rail member
2
which has been loaded with ten (10) balls
3
is loaded with, for example, six (6) balls
3
, and hence, the ability for bearing moment load, radial load and thrust load is deteriorated.
Moreover, with the cam-follower type drawer device, because the wheels generally have backlash or looseness, the movable rail member
2
does not smoothly slide, and furthermore, because the wheel has a cylindrical structure, a direction along which a load is received is determined, and hence, the thrust load cannot be received.
SUMMARY OF THE INVENTION
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a rolling guide device capable of taking a large expansion/contraction stroke and sufficiently bearing moment load, radial load and thrust load at any expanded (contracted) attitude and also provide a drive system incorporated with such a rolling guide device.
This and other objects can be achieved according to the present invention by providing, in one aspect, a rolling guide device comprising:
a track rail formed with a rolling member rolling surface extending along a longitudinal direction thereof;
a movable rail formed with a loaded rolling member rolling surface extending along a longitudinal direction thereof so as to oppose the rolling member rolling surface of the track rail;
a track rail side rolling member circulation passage formed to the track rail so as to circulate the rolling members rolling between the track rail and the movable rail;
a movable rail side rolling member circulation passage formed to the movable rail so as to circulate the rolling members rolling between the track rail and the movable rail; and
a number of rolling members disposed and arranged in the track rail side rolling member circulation passage and the movable rail side rolling member circulation passage.
According to this aspect, when the movable rail slides with respect to the track rail, the rolling members arranged between the track rail and the movable rail endlessly circulate in the track rail side rolling member circulation passage and the movable rail side rolling member circulation passage while rolling therealong. As mentioned, because the rolling members circulate in the endless manner, even if the rolling member slides during the rolling motion, there is no causing of a case that a cage is shifted from the initial position as in the conventional structure, and hence, a large expansion (contraction) stroke is obtainable. Furthermore, in an optional expanded (contracted) attitude, there remains a considerable distance between the track rail side rolling member circulation passage and the movable rail side rolling member circulation passage, so that a rolling guide device, which can bear even the moment load, can be realized.
Further, when the movable rail slides and its stroke is made large, the considerable distance corresponding to this stroke is made short and the capability of bearing the moment load is reduced. However, according to the present invention, the movable rail does not come off from the balls, so that the capability of bearing the moment load is not extremely reduced. Moreover, because the movable rail does not come off from the balls and the number of the rolling members supported at an optional expansion (contraction) attitude is not changed, in contrast to the conventional slide rail, there can be provided a rolling guide device bearing the constant radial load and thrust load.
In the above aspect, the following preferred embodiments or examples may be provided with advantageous functions and effects thereof.
The track rail side rolling member circulation passage is formed in one longitudinal end side of the track rail and the movable rail side rolling member cir
Hoshide Kaoru
Shirai Takeki
Teramach Akihiro
Armstrong Westerman & Hattori, LLP
Kramer Devon
Schwartz Christopher P.
THK Co. Ltd.
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