EP1914776A1

EP1914776A1 - Bearing assembly of switching mechanism for air circuit breaker and fabrication method thereof

Info

Publication number: EP1914776A1
Application number: EP07019933A
Authority: EP
Inventors: Kil-Young Ahn; Hong-Ik Yang; Sang-Chul Lee; Ki-Hwan Kim
Original assignee: LS Industrial Systems Co Ltd
Current assignee: LS Electric Co Ltd
Priority date: 2006-10-17
Filing date: 2007-10-11
Publication date: 2008-04-23
Anticipated expiration: 2027-10-11
Also published as: MY153158A; RU2346348C1; DE602007005572D1; EP1914776B1; ES2343753T3; KR100807542B1; CN101183621A; CN101183621B

Abstract

A bearing assembly of a switching mechanism for an air circuit breaker having multiple rotational shafts, that includes: a trust bearing (3); and a trust bearing support member (4) that includes an axial hole wall (4d), an inner diameter part (4c) contacting with the trust bearing, a flange part (4a) extending from the inner diameter part, a rounded part (4b) formed between the inner diameter part (4c) and the flange part (4a), and an annular recess portion (4e) formed at a lower portion of the flange part by pressing to lengthen the inner diameter part and shorten the length of the rounded part to thus increase the area contacting with the trust bearing. Because the contact area between the trust bearing and the bearing support member is increased, deformation of the bearing support member due to an axial load can be minimized.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a switching mechanism of an air circuit breaker, a type of a low voltage circuit breaker, and more particularly, to a bearing assembly, which supports at least one of rotational shafts such that it can be smoothly rotated, capable of effectively supporting a bearing that receives much axial load.

2. Description of the Related Art

The air circuit breaker includes a switching mechanism that opens or closes a current conduction circuit, a cradle unit for housing the switching mechanism and having a terminal part connected with an external power source and a load, and a circuit monitoring and controlling unit that senses a fault current of the current conduction circuit as connected and provides a driving power for automatically moving the switching mechanism to a breaking (trip) position.
The present invention relates to the switching mechanism, which is called as a main circuit part of the major parts of the air circuit breaker, and the related art bearing assembly will now be described.
In the air circuit breaker, a charging operation of a closing spring, a closing operation and a breaking (trip) operation are basic operations of the air circuit breaker. In particular, during the charging operation, much load is applied to a cam shaft that charges the closing spring by large charged elastic energy according to high elastic coefficient of the closing spring.
Thus, in order to tolerate much load and smooth rotation, the bearing is used, and a support structure may be deformed or damaged by the load in direction of axis according to the structure that supports the bearing.
The switching mechanism for an air circuit breaker as shown in FIG .1 is installed between both of side plates 6a, 6b, reference numeral 1 is a cam shaft, namely, a rotational shaft, of a charging cam (refer to reference numeral 2 in FIG. 2) for charging the closing spring (not shown), and reference numeral 5 is a handle connected with one end of the cam shaft 1 to rotate the cam shaft 1 manually. The cam shaft 1 penetrates between both side plates 6a and 6b and extends from one of the side plates 6a and 6b.
As shown in FIG. 2, the bearing assembly of the switching mechanism is installed at an outer side of the two charging cams 2 on the cam shaft 1, respectively, to support the cam shaft 2 such that the cam shaft 2 can be smoothly rotated.
With reference to FIG. 3, the bearing assembly according to the related art includes a trust bearing 3 which has a flange part and substantially has a ring shape, and a trust bearing support member 4 that rotatably supports the trust bearing 3.
In the bearing assembly according to the related art, the detailed structure of the trust bearing support member 4 that rotatably supports the trust bearing 3 will now be described with reference to FIG. 4.
The trust bearing support member 4 according to the related art includes a flange part 4a allowing the trust bearing 3 to be mounted thereon, an inner diameter part 4c with which the trust bearing comes in contact while being rotated, a rounded part 4b formed between the flange portion 4a and the inner diameter portion 4c, and an axial hole wall 4d allowing the cam shaft 1 to pass therethrough.
The method for fabricating the bearing assembly according to the related art will now be described with reference to FiGs. 5 and 6.
First, a row material (not shown) of the substantially rectangular trust bearing support member 4 is prepared.
Next, as shown in FIG. 5, the raw material is pressed downwardly to obtain a substantially U-shaped semi-processed material with a flange.
And then, as shown in FIG. 6, a middle portion in the direction of diameter of the semi-processed material is punctured to form a substantially U-shaped trust bearing support member 4 with a central through hole.
Thereafter, the trust bearing 3 is inserted into the inner diameter part of the substantially U-shaped trust bearing support member 4 to complete fabrication of the bearing assembly as shown in FIG. 3.
However, in the bearing assembly according to the related art, the rounded part 4b is formed to be large (namely, the height of the rounded part 4b is formed to be long in FIG. 4) while the inner diameter part 4c contacting with the trust bearing 3 is shortened.
Thus, the load of the trust bearing that receives much axial load is concentrated to the short inner diameter part 4c, causing a problem that the trust bearing support member 4 is deformed and damaged.

SUMMARY OF THE INVENTION

Therefore, in order to address the above matters the various features described herein have been conceived. One aspect of the exemplary embodiments is to provide a bearing assembly of a switching mechanism for an air circuit breaker, in which an inner diameter part that contacts with a trust bearing is long to distribute an axial load applied to a trust bearing support member.
Another aspect of the exemplary embodiments is to provide a method for fabricating a bearing assembly of a switching mechanism for an air circuit breaker.
This specification provides a bearing assembly of a switching mechanism for an air circuit breaker having multiple rotational shafts, that may include: a trust bearing that supports at least one of the rotational shafts such that it can be smoothly rotated and includes an annular body part and a flange part extending from the body part; and a trust bearing support member that includes an axial hole wall forming an axial hole through which the rotational shaft passes, an inner diameter part extending from the axial hole wall and contacting with the trust bearing, a flange part extending from the inner diameter part, a rounded part formed between the inner diameter part and the flange part, and an annular recess portion formed at a lower portion of the flange part by pressing to lengthen the inner diameter part and shorten the length of the rounded part to thus increase the area contacting with the trust bearing.
This specification also provides a method for fabricating a bearing assembly of a switching mechanism for an air circuit breaker, that may include: shaping a U-shaped unfinished material with a flange part by pressing a flat raw material downwardly; shaping an annular recess portion by pressing a lower portion of the flange part of the unfinished material upwardly; shaping an axial hole by puncturing the bottom of the unfinished material; and assembling by inserting an annular trust bearing into the the bearing support member.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:

FIG. 1 is a perspective view of a switching mechanism for an air circuit breaker in which a bearing assembly is installed according to the present invention or the related art;
FIG. 2 is a perspective view showing a state that the bearing assembly is installed on a cam shaft in the switching mechanism for an air circuit breaker according to the present invention or the related art;
FIG. 3 is a perspective view showing an assembled state of the bearing assembly of the switching mechanism for an air circuit breaker according to the present invention or the related art;
FIG. 4 is a sectional view of a bearing support member of the bearing assembly of the switching mechanism for an air circuit breaker according to the related art;
FIG. 5 is a view showing a process of shaping a U-shaped intermediate material with a flange part by pressing downwardly a flat raw material in fabricating the bearing assembly of the switching mechanism for an air circuit breaker according to the related art;
FIG. 6 is a view showing a process of forming a through hole by puncturing the bottom of the U-shaped unfinished work of the bearing assembly of according to the related art;
FIG. 7 is a sectional view of a bearing support member of the bearing assembly of the switching mechanism for an air circuit breaker according to the present invention;
FIG. 8 is a perspective view of the bearing support member of the bearing assembly of the switching mechanism for an air circuit breaker according to the present invention; and
FIG. 9 is a view showing a process of a method for producing the bearing assembly of the switching mechanism for an air circuit breaker according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The object, the construction for achieving the object, and an operational effect of the present invention will be clearly understood through the description on the embodiment of the present invention made with reference to the accompanying drawings.
As shown in Figure 3, the bearing assembly according to the present invention includes a trust bearing 3 which has a flange part and substantially has a ring shape, and a trust bearing support member 4 that rotatably supports the trust bearing 3.
In the bearing assembly according to the present invention, the detailed structure of the trust bearing support member 4 that rotatably supports the trust bearing 3 will now be described with reference to FIGs. 7 and 8.
The trust bearing support member 4 according to the present invention includes a flange part 4a allowing the trust bearing 3 to be mounted thereon, an inner diameter part 4c with which the trust bearing 3 comes in contact while being rotated, a rounded part 4b formed between the flange part 4a and the inner diameter part 4c, an axial hole wall 4d allowing the cam shaft 1 to pass therethrough; and an annular recess portion 4e formed at a lower portion of the flange part 4a by pressing to lengthen the inner diameter part 4c and shorten the length of the rounded part 4b to thus increase the area contacting with the trust bearing 3.
The annular recess portion 4e of the trust bearing support member 4 is formed at a portion where an outer diameter part and the flange party 4a of the trust bearing support member 4 are met.
The method for producing the bearing assembly according to the present invention will now be described with reference to FIG. 9.
First, as shown in the uppermost drawing of the Figure 9, a raw material of the substantially rectangular trust bearing support member 4 is prepared.
Next, as shown in the drawing right under the uppermost of the Figure 9, the raw material is pressed downwardly to obtain a substantially U-shaped unfinished work with a flange.
And then, as shown in the third drawing from the uppermost of the Figure 9, a lower portion of the flange part of the unfinished work is pressed upwardly to form an annular recess.
Thereafter, as shown in the forth drawing from the uppermost of the Figure 9, middle portion in the direction of diameter of the unfinished work is punctured to form a substantially U-shaped trust bearing support member 4 with a central axial hole.
Thereafter, as shown in the lowermost drawing of the Figure 9, the trust bearing 3 is inserted into the inner diameter part of the substantially U-shaped trust bearing support member 4 to complete production of the bearing assembly.
As so far described, compared with the related art, in the bearing assembly according to the present invention, because the inner diameter part contacting with the bearing is lengthened, much axial load can be dispersed, and thus, the bearing can be effectively supported.
In addition, by using the method for producing the bearing assembly according to the present invention, the bearing which can be effectively supported is produced.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims

A bearing assembly of a switching mechanism for an air circuit breaker having multiple rotational shafts, the bearing assembly comprising:
a trust bearing that supports at least one of the rotational shafts such that it can be smoothly rotated and includes an annular body part and a flange part extending from the body part; and

a trust bearing support member that includes an axial hole wall forming an axial hole through which the rotational shaft passes, an inner diameter part extending from the axial hole wall and contacting with the trust bearing, a flange part extending from the inner diameter part, a rounded part formed between the inner diameter part and the flange part, and an annular recess portion formed at a lower portion of the flange part by pressing to lengthen the inner diameter part and shorten the length of the rounded part to thus increase the area contacting with the trust bearing.
The assembly of claim 1, wherein the annular recess portion of the trust bearing support member is formed at a portion where an outer diameter part and the flange party of the trust bearing support member are met.
A method for fabricating a bearing assembly of a switching mechanism for an air circuit breaker, the method comprising:
shaping a U-shaped unfinished work with a flange part by pressing a flat raw material downwardly;

shaping an annular recess portion by pressing a lower portion of the flange part of the unfinished work upwardly;

shaping an axial hole by puncturing the bottom of the unfinished work; and

assembling by inserting an annular trust bearing into the bearing support member.