Title: Linear rolling bearing
Abstract: A linear rolling bearing has a guide carriage (1) that is U-shaped in cross-section and has two U-legs (6). The guide carriage (1) is slidably supported through balls (3) on two longitudinal sides of a guide rail (2). Each U-leg (6) comprises on an inner surface opposing the guide rail (2) a ground raceway (10) for the balls (3). The raceway (10) is made by a grinding wheel whose diameter is larger than the diagonal dimension of the carriage cavity (7). According to the invention, a stop surface (12) having a retaining contour for a guide member (4) containing the balls (3) is configured on a guide rail-distal outer surface of each U-leg (6) of the guide carriage (1), and the raceway (10) on one of the two U-legs (6) and the stop surface (12) having the retaining contour on the other of the two U-legs (6) are made in common in one work step by the grinding wheel.
Patent Number: 6,904,679 Issued on 06/14/2005 to Greiner
| Inventors:
|
Greiner; Heinz (Ebersbach, DE)
|
| Assignee:
|
Ina Walzlager Schaeffler oHG (DE)
|
| Appl. No.:
|
848462 |
| Filed:
|
May 18, 2004 |
Foreign Application Priority Data
| Feb 09, 2000[DE] | 100 05 719 |
| Current U.S. Class: |
29/898.03; 384/45; 451/52 |
| Intern'l Class: |
B21D 053/10; B24B007/30 |
| Field of Search: |
29/89803
451/52
384/45,43,49
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Nguyen; Xuan Lan
Attorney, Agent or Firm: Muserlian, Lucas and Mercanti
Parent Case Text
This application is a division of U.S. patent application Ser. No. 09/777,122
filed Feb. 5, 2001, now U.S. Pat. No. 6,808,309.
Claims
1. A method of producing a linear rolling bearing comprising a guide carriage
with a U-shaped cross-section having a U-crossbar and two U-legs so that the guide
carriage forms a carriage cavity and partially surrounds a guide rail while being
slidably supported through balls on two longitudinal sides of the guide rail, each
U-leg of the guide carriage having on an inner surface opposing the guide rail
a ground raceway with an approximately quarter circle cross-section for the balls,
comprising forming the raceway with a grinding wheel whose diameter is larger than
a diagonal dimension of the carriage cavity and whose axis of rotation is situated
outside of the guide carriage and forms an acute angle (α) with an axis of
symmetry of the guide carriage, wherein a stop surface having a retaining contour
for a guide member containing the balls is configured on a guide rail-distal outer
surface of each U-leg of the guide carriage, and the raceway on one of the two
U-legs and the stop surface having the retaining contour on the other of the two
U-legs are made in common in a single work step by the grinding wheel.
2. The method of claim 1 wherein the acute angle (α) that the axis of rotation
of the grinding wheel forms with the axis of symmetry of the guide carriage is
about 15°.
3. The method of claim 1 wherein the guide member containing the balls are detachably
fixed on the guide carriage and extend in longitudinal direction from raceways
of the guide rail, wherein the balls form endless ball circuits and the guide member
comprises for each ball circuit, a region for load-bearing balls, a return canal
for returning balls and two deflecting canals that connect the region for load-bearing
balls and the return canal to each other at ends thereof.
4. The method of claim 3 wherein each return canal made in the guide member comprises
an opening extending along an entire length of the return canal, and said opening
also extends along each deflecting canal.
5. The method of claim 4 wherein a width of the opening of the return canal is
smaller than a diameter of the balls inserted in the return canal.
Description
FIELD OF THE INVENTION
The invention concerns a linear rolling bearing comprising a guide carriage with
a U-shaped cross-section having a U-crossbar and two U-legs so that the guide carriage
forms a carriage cavity and partially surrounds a guide rail while being slidably
supported through balls on two longitudinal sides of the guide rail, each U-leg
of the guide carriage having on an inner surface opposing the guide rail a ground
raceway with an approximately quarter circle cross-section for the balls, the raceway
being made by a grinding wheel whose diameter is larger than a diagonal dimension
of the carriage cavity and whose axis of rotation is situated outside of the guide
carriage and forms an acute angle with an axis of symmetry of the guide carriage.
BACKGROUND OF THE INVENTION
Raceways of carriages for profiled rail guides are made either using small
vertical grinding wheels or several inclined grinding wheels arranged behind one
another. Small grinding wheels result in unfavorable grinding values, short tool
lives and poor surface quality. If several inclined wheels are used, the inner
space of the guide carriage i.e., the carriage cavity likewise limits the size
of the wheels. The advantage, however, is the inclined position of the grinding
wheel. Therefore a limited but somewhat larger wheel is used.
At the same speed of rotation, a higher peripheral speed is obtained with a grinding
wheel having a large diameter than with a wheel having a small diameter. With a
large diameter, a higher grinding performance and a prolongation of the service
life of the wheel are obtained. The rotational speed of the grinding spindle cannot
be infinitely increased because this would lead to a destruction of its bearings.
The publication EP 0 318 980 B1 discloses a linear ball bearing having a guide
carriage, designated as a bearing body, that has a leg section with an upper groove
with an approximately semi-circular cross-section for load-bearing balls and a
lower groove with an approximately quarter circle cross-section for load-bearing
balls. A drawback of this lies in the continuation of the radius of the upper groove
up to the vertical inner wall of the leg section. This necessarily means that for
making the upper groove by grinding, a small grinding wheel must be used.
The publication DE 33 31 287 C2 discloses a method of grinding the bearing body
of a linear ball bearing. In this method, two raceways for load-bearing balls are
ground on the inner surface of a U-crossbar of a guide carriage using a grinding
wheel with a large diameter which is placed inclined to the guide carriage. The
return canals for the balls that are arranged in circuits are configured as bores
in the guide carriage and have to be made in special work steps in addition to
the raceways for the load-bearing balls.
The publication DE 33 04 895 C2 shows a linear ball bearing with bearing bodies
in which each ball recirculating shoe or bearing body comprises attached sheet
metal parts viz., a W-shaped ball retainer for the load-bearing balls and a cover
with a U-shaped cross-section which outwardly closes ball-guiding grooves for the
non-loaded returning balls. Due to these additional sheet metal parts, the structure
and assembly of the ball recirculating shoe is complicated and expensive.
The publication DE 30 19 131 A1 discloses a linear ball bearing in which continuous
longitudinal openings are provided in the load-bearing regions and the return regions
for the balls in the guide elements that are made as retaining plates. Therefore
each guide element not only has in its ball region a narrow outwardly oriented
opening but is also open towards the machine element that acts as a guide carriage.
The balls extend through these openings and are guided on longitudinal raceways
that have to be made as grooves in the machine element so that additional machining
and tool costs are incurred.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a linear rolling bearing which can
be made with low machining costs and a short machining time under good grinding
conditions so that raceways with a very high surface quality can be realized.
This and other objects and advantages of the invention will become obvious from
the following detailed description.
SUMMARY OF THE INVENTION
The invention achieves the above objects by the fact that a stop surface having
a retaining contour for a guide member containing the balls is configured on a
guide rail-distal outer surface of each U-leg of the guide carriage, and the raceway
on one of the two U-legs and the stop surface having the retaining contour on the
other of the two U-legs are made in common in one work step by the grinding wheel.
Due to the simultaneous grinding of a raceway and a stop surface, the machining
time of the guide carriage of the linear bearing is considerably shortened.
Further advantageous features of the invention and a detailed description
of one example of embodiment of the invention shown in the drawings will be given hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a linear bearing of the invention, partly in cross-section and
partly in a front view;
FIG. 2 shows a guide carriage of the linear bearing in cross-section, with a
grinding wheel in contact with the surfaces to be ground.
DETAILED DESCRIPTION OF THE DRAWINGS
The linear rolling bearing illustrated in FIG. 1 comprises a guide carriage
1
that is supported through balls
3 on a guide rail
2 and is displaceable
in the longitudinal direction of the rail. The linear rolling bearing is configured
with two guide members
4 as a four-row bearing. Each guide member
4
contains two canals that effect the deflection and return of the balls
3
that are arranged in endless circuits. The guide carriage
1 has a U-shaped
configuration and comprises a U-crossbar
5 and two U-legs
6 continuing
therefrom. In this way, the guide carriage
1 forms a carriage cavity
7
and partially surrounds the guide rail
2 so that this projects into the
carriage cavity
7.
The ground raceway
10 made by grinding has an approximately quarter circle
cross section for the balls
3. The ground raceway
10 of each U-leg
6 of the guide carriage us situated nearer the U-crossbar
5, and
each U-leg
6 comprises on the inner surface another raceway
11 that
is situated further away from the U-crossbar
5 and has an approximately
quarter circle cross-section for the balls
3.
Two raceways for balls
3 are configured on each longitudinal side of the
guide rail
2 i.e., on each side of the guide rail
2 there is configured
an upper raceway
8 and a lower raceway
9. These raceways
8
and
9 are parallel to each other in the longitudinal direction of the guide
rail
2. The guide carriage
1 is supported on these raceways through
the balls
3. For this purpose, the guide carriage
1 has on the inner
surface of each U-leg
6 adjacent the guide rail
2, an upper raceway
10 that is situated nearer the U-crossbar
5 and a lower raceway
11
that is situated further away from the U-crossbar
5.
The load-bearing balls
3 are arranged on each longitudinal side of the
guide rail
2 between each of the raceways
8 and
9 of the guide
rail
2 and corresponding raceways
10 and
11 of the guide carriage
1. Two of the four endless circuits of balls
3 are arranged on each
longitudinal side of the guide rail
2. Each guide member
4 surrounds
one of the U-legs
6 and is retained on a stop surface
12 of this
U-leg
6. The stop surface
12 has a retaining contour and is situated
on the guide rail-distal outer side of each U-leg
6. Two return canals for
the balls i.e., an upper return canal
13 and a lower return canal
14,
extending parallel to the raceways
10 and
11 of the U-leg
6
are formed in the guide member
4. At their ends, these canals merge into
deflector canals that connect the return canals
13 and
14 to the
associated regions of load-bearing balls
3 between the raceways
8
and
10, and between the raceways
9 and
11 respectively. Thus,
the upper return canal
13 is connected to the raceway
10, and the
lower return canal
14 is connected to the raceway
11.
The return canals
13 and
14 have an inner diameter corresponding
to the diameter of the balls
3 and a radial opening
15 that extends
in the longitudinal direction of the guide rail
2 and whose width is smaller
than the ball diameter. On their longitudinal sides opposite the opening
15,
the return canals
13 and
14 comprise a common bottom wall
16
so that the balls
3 are retained in their respective return canals
13
and
14 in the guide member
4 even when the guide member
4
is separated from the guide carriage
1. The guide member
4 can be
made as an elastic component out of a plastic or a metal. Between its two raceways
10 and
11 for the load-bearing balls
3, the U-leg
6
comprises a projecting lug
17 that helps in unmistakably fixing and retaining
the guide member
4 in the bearing.
FIG. 2 shows the manner in which the guide carriage
1 is machined with
a grinding wheel
18. The axis of rotation
19 of the grinding wheel
18 is situated outside of the guide carriage
1 and is disposed at
an acute angle α to the axis of symmetry
20 of the guide carriage
1. This permits a simultaneous grinding both of the raceway
10 situated
nearer the U-crossbar
5 and the raceway
11 situated further away
from the U-crossbar
5 of the inner surface of one of the U-legs
6
using one part of the grinding wheel
18 and, at the same time, a grinding
of the stop surface
12 on the outer surface of the other U-leg
6
using another part of the grinding wheel
18. The acute angle α that
the axis of rotation
19 of the grinding wheel
18 forms with the axis
20 of symmetry of the guide carriage
1 is about 15°. To enable
a part of the grinding wheel to be inserted into the carriage cavity and grind
the raceways
10 and
11, both the raceways
11 of the guide
carriage
1 situated further away from the U-crossbar
5 end at an
imaginary connecting plane
21 that extends through the centers of the load-bearing
balls
3 circulating on the raceways
11 and limits the two U-legs
6 on their undersides.
*
