TECHNICAL FIELD
[0001] The present invention relates to a vacuum interrupter, especially relates to a vacuum
interrupter for a vacuum circuit breaker. Moreover, the present invention also relates to a
vacuum circuit breaker.
BACKGROUND
[0002] A vacuum interrupt is the key element of a vacuum switch or a vacuum circuit
breaker for controlling the electrical arc. Switching on and switching off of current and
electrical arc are realized by the movement of contact in the vacuum interrupter. Nowadays, the
vacuum interrupter mainly includes the following components, i.e., a movable contact, a fixed
contact and conductive rods for the movable and fixed contacts, an insulation housing, a shield,
bellows and the like. For instance, the CN utility model patent ZL 200520034035.3 discloses a
conventional vacuum interrupter. The existing movable contact conductive rod is configured to
conduct the current through the moveable contact on one hand, and on the other hand serves as
actuating means for moving the movable contact to disengage from the fixed contact. In the
vacuum interrupter, for conducting the current, it is preferred to maximize the surface area of
the movable contact conductive rod to facilitate heat dissipation, whereas to improve the
efficiency of the vacuum interrupter and the reliability of the vacuum circuit breaker, it is
desirable to effectively minimize the mass of the moving components including the movable
contact conductive rod. Therefore, the existing movable contact conductive rod has to
compromise in these two points.
[0003] Moreover, to improve short-circuit current interrupting capacity of the vacuum
interrupter, a technology of controlling vacuum electrical arc magnet field has been developed.
It has been found that the magnet field generated by the current can effectively facilitate
interruption of the electrical arc during switching off the movable and fixed contacts, so as to
rapidly extinguish the arc. In the prior art multiple methods have been developed to enhance the
magnet field. One of the conventional means is to form spiral grooves in the contacts (including
W020141090089 PCTlCN20131088030
the movable and fixed contacts), prolonging the current path in the movable contact to enhance
the magnet field. However, as the distance between the movable contact and the fixed contact
increases, the magnet field will decrease significantly as the separated distance increases to be
insufficient to control the electrical arc in the large separated distance. The spiral grooves can
provide little help to prevent such a magnet field decrease.
[0004] Therefore, the inventor intends to improve the prior art to provide a vacuum
interrupter as well as a vacuum circuit breaker having the same which can at least partially
overcome the above deficiencies in the prior art.
DESCRIPTION OF THE INVENTION
[0005] According to one aspect of the invention, a vacuum interrupter is provided which
comprises: a housing; a fixed contact received in the housing; a movable contact received in the
housing and configured to be movable to engage with or disengage fiom the fixed contact; a
conductive seat fixedly mounted in the housing and configured to maintain an electrical
connection with the movable contact; a flexible (soft) electrical connection feature received in
the housing for connecting the movable contact with the conductive seat; and an operating
mechanism for actuating a movement of the movable contact.
[0006] As compared with the known conductive rod which is used for electrical connection
with movable contact and also serves as the operating mechanism for the movement of the
movable contact, the vacuum interrupter of the present invention provides a flexible electrical
connection feature such that the electrically conductive member which is electrically connected
with the movable contact and the operating mechanism for the movable contact are configured
separately, such that the electrically conductive member, i.e. the conductive seat, may be
designed having a bigger size for facilitating the heat dissipation of the vacuum interrupter,
while the mass of movable components in the vacuum interrupter will not increase significantly
or even will decrease. In addition, the operating mechanism may be made of more various
materials. For example, it is possible to utilize the materials whi& have lighter weight or a
better heat dissipation.
[0007] According to an embodiment of the invention, the conductive seat may be in form of
a hollow member with a central through-hole. The operating mechanism may include an
operating rod in rigid connection with the movable contact, and an actuator configured to move
at least the operating rod and the movable contact to disengage from the fixed contact, wherein
the operating rod passes through the central through-hole. By means of such an arrangement,
the conductive seat may advantageously have an outer and inner heat dissipation surfaces.
Moreover, the conductive seat may advantageously have an interior space for receiving other
components of the vacuum interrupter, such as the bellows and contact springs, such that a
more compact design of the vacuum interrupter is provided.
[0008] According to an especially preferable embodiment of the invention, the flexible
electrical connection feature includes at least one flexible conductive strip arranged between
the movable contact and the conductive seat, and the flexible conductive strip is arranged
inclinedly relative to a longitudinal axis of the movable contact, or helically around the
longitudinal axis.
[0009] As mentioned above, in the existing vacuum interrupter, as the separated distance c+f
the movable and fixed contacts increases, the longitudinal magnet field generated between the
movable contact and the fixed contact decreases, which is detrimental to the breaking ability of
the movable and fixed contacts. By means of the inclined or helical arrangement of the flexible
conductive strip in the preferable embodiment of the present invention, as the separated
distance of the movable and fixed contacts increases, the inclined or helical angle of the
flexible conductive strip relative to the plane of the movable contact longitudinal axis decreases
accordingly. Therefore, a component of the current that produces the longitudinal magnet field
increases, such that the magnet field will decrease little or in some cases will maintain
unchanged or even increaseas the separated distance increases. Therefore, the decrease of the
inclined or helical angle can cause a positive effect that the magnet field generated between the
movable contact and the fixed contact will not decrease inversely proportional to the increase
of the separated distance, such that the breaking ability of the movable and fixed contacts is
improved.
W02014/090089 PCT/CN2013/088030
[0010] According to a further preferable embodiment of the invention, the at least one
flexible conductive strip comprises a plurality of flexible conductive strips. Preferably, the
plurality of flexible conductive strips have a consistent inclined or helical direction which will
produce a superimposed effect of enhancing the longitudinal magnet field.
[0011] It should be appreciated by the person skilled in the art that the conductive seat may
perform a functionality of conduction similar to the prior art conductive rod, such that during
the switching on (engagement) or switching off (disengagement) of the movable and fixed
contacts, the conductive seat keep in an electrical connection with the movable contact, and as
known in the art, the conductive seat may be connected to a corresponding electrical element of
the vacuum intenupter or the vacuum circuit breaker via terminals.
[0012] In some embodiments of the invention, the electrical connection between the
conductive seat and the movable contact can be substantively provided by the flexible electrical
connection feature, no matter when in the switching on or in the switching off.
[0013] In an alternative, preferable embodiment of the invention, the operating rod
comprises a switching-on conductive feature in contact or connection with the movable contact,
wherein the switching-on conductive feature is configured to electrically connect with the
conductive seat when the movable contact engages with the fixed contact, and to electrically
disconnect or be separated h m the conductive seat when the movable contact disengages from
the fyted contact. During switching on of the movable and fixed contacts, therefore, most of or
substantially all the current of the movable contact flows through the switching-on conductive
feature to the conductive seat. As an explanation but not limitation, this may be because the
operating rod has a shorter conductive path and/or a greater conductive section than the flexible
strips. It should be appreciated by the person skilled in the art that the switching-on conductive
feature may be made of a conductive material same as or different from that of the flexible
electrical connection feature, although the conductivity of the conductive material of the
switching-on conductive feature is preferably not worse than that of the flexible electrical
connection feature. When the movable and fixed contacts switch off, the switching-on
conductive feature will disengage or be separated from the conductive seat, such that most of or
all the current of the movable contact is conducted by the flexible electrical connection feature.
w02014/090089 PCTlCN20131088030
The switching-on conductive feature of the invention not only has a current conductive
capacity same as or even better than the prior art design during switching on, and may obtain
the merits provided by the flexible electrical connection feature during switching off, such as
an increased heat dissipation surface, decreased mass of movable components andlor decreased
inclined or helical angle for relatively enhancing the longitudinal magnet field.
[0014] According to a particular embodiment of the invention, the switching-on conductive
feature is provided, including a flange protruding from the rod body of the operating rod. The
central through-hole of the conductive seat has a first opening portion such as an upper opening
portion with a smaller diameter and a second opening portion such as a lower opening portion
with a greater diameter. The flange has a shape at least partially corresponding to the first
opening portion. Therefore, the flange at least partially or preferably engages with the first
opening portion during switching on. During switching off, as the operating rod moves e.g.,
downwards relative to the conductive seat, the flange moves into the second opening portion
with the greater diameter so as to be spaced from the conductive seat.
[0015] According to another particular embodiment of the invention, a switching-on
conductive feature is provide which similarly defines a flange protruding from the rod body of
the operating rod, and the central through-hole of the conductive seat accordingly defines a first
contacting portion and a second insulating portion. Therefore, during switching on, the flange is
positioned to contact with the first contacting portion, while during switching off, the flange
moves into the second insulating portion and thus is electrically insulated from the conductive
seat. The second insulating portion may comprise an annular insulating sleeve mounted to the
wall of the central through-hole or insulating material layer or integrated with the wall of the
hole.
[0016] Although two specific switching-on conductive features are described, other kinds of
configuration are still possible, as long as it is able to form main current path through the
operating rod during switching on and cut off the current path through the operating rod during
switching off. For example, the central through-hole of the conductive seat can be configured to
be tapered towards the movable contact, and the corresponding portion of the operating rod is
conductive and is configured to be tapered too, such that the tapering surfaces of the conductive
W02014/090089 PCTlCN20131088030
seat and the operating rod engage with each other during switching on, while during switching
off, as the operating rod moves downwards, a gap is formed between the two tapering surfaces
such that the two tapering surfaces are spaced from each other. Moreover, it should be
appreciated by the person skilled in the art that the switching-on conductive feature may be
generally formed on the upper portion of the conductive rod and comprise or consist of the
conductive material, while other portions of the conductive rod such as the lower portion may
as desired have the same or different material.
[0017] According to one preferred embodiment of the invention, in the case that the flexible
electrical connection feature includes a plurality of flexible conductive strips, the vacuum
interrupter may further comprise a separating support for supporting and separating at least
some, or preferably all, of the plurality of flexible conductive strips. Therefore, during
switching on, contact and engagement between the adjacent flexible conductive strips can be
reduced or avoided, which otherwise may shorten the path flowing through the flexible
electrical connection feature during switching on and thus is detrimental to the ability of the
inclinedly or helically flexible conductive strips to improve the longitudinal magnet field.
According to a further preferable embodiment, the separating support may be mounted onto or
integral with the conductive seat. It, however, should be appreciated by the person skilled in the
art that the separating support may have an electrical resistance greater than that of the flexible
electrical connection feature, or the separating support may make no contact with or is in
insulation from the conductive seat, such barelyno or little current flows to the conductive seat
through the separating support. In a preferable embodiment, the separating support is made of
stainless steel.
[0018] According to a particular embodiment of the invention, the separating support may
have a plurality of circumferentially arranged holes, one flexible conductive strip passing
through each hole.
[0019] According to another particular embodiment of the invention, the separating support
may have a plurality of radially extending radial bars, wherein a space is defined between the
two adjacent radial bars. Preferably, one flexible conductive strip passes through each space.
WO20141090089 PCTICN2013/088030
[0020] It should be appreciated by the person skilled in the art that the prior art bellows
maybe combined in all embodiments of the present invention, and the prior art bellows may be
configured relative to the operating rod in a way as known in the prior art, which can be
achieved by the embodiments of the invention and fall into the scope of the present invention.
For example, one end of the bellows is in peripherally sealing connection with the operating
rod, and the other end is in sealing connection with the outside or inside of the housing around
a portion of the operating rod to be extended outside the housing.
[0021] Alternatively, according to a particularly preferable embodiment of the invention, one
end of which is in peripherally sealing connection with the operating rod, and the other end is
in peripherally sealing connection with the central through-hole, e.g., with the first opening
portion of the central through-hole, to define a vacuum space within the housing. By means of
such arrangement, the interior of the bellows is in vacuum. Because the bellows can inherently
bear a greater external pressure, such arrangement of the bellows may allow a longer service
life. In addition, by means of such arrangement of the bellows, the end of the bellows which is
in sealing connection with the operating rod may be the lower end far away from the movable
contact, while the end of the bellows which is in sealing connection with the conductive seat is
the end near to the movable contact, such that the bellows is normally maintained in contraction
or compression during the switching on, and stretches only during switching off, which may
significantly prolong the service life of the bellows.
[0022] According to a preferable embodiment of the invention, a bellows bush is mounted
inside the bellows so as to prevent the electrical arc from burning the bellows through the
central hole of the conductive seat which will otherwise cause leakage. It is desired that the
bellows bush is mounted to the conductive seat around the first opening portion.
[0023] It should be appreciated by the person skilled in the art that the prior art contact
spring can be combined in all embodiments of the present invention, and the prior art contact
spring may be configured relative to the operating rod in a known way, all of which can be
achieved in the embodiments of the invention and fall into the scope of the present invention.
According to a preferable embodiment of the invention, for example, one end of the contact
spring may rest against the operating rod and the other end may rest against the fixed part of the
W02014/090089 PCTICN2013/088030
housing. According to an example, the operating rod forms a stopping portion extending
radially from the rod body for abutting against the upper end of the spring. In the housing a
fixture is mounted for abutting against the lower side of the spring. According to another
example, a stopping portion of the operating rod abuts against the lower end of the spring, and
the conductive seat forms another stopping portion extending inwards &om the central hole for
abutting against the upper end of the spring. Moreover, a variety of contact spring arrangements
are possible.
[0024] According to a preferred embodiment of the invention, the hollow conductive seat
may define a receiving groove which receives the bellows and/or the spring, so as to provide a
compact arrangement. According to an example, the receiving groove is of the second opening
portion of the central through-hole, although the receiving groove may be formed separately
from the second opening portion. Also, other arrangements are conceivable.
[0025] According to an embodiment of the invention, the vacuum interrupter may further
include a second interior shield inside the housing. Some prior art designs also have an interior
shield which receives the fixed contact, the movable contact and a portion of the conductive
seat in the vacuum condition. However the interior shield of the invention receives the flexible
electrical connection feature and a portion of the conductive seat, preferably the portion of the
conductive seat which is connected to the flexible electrical connection feature. The
above-mentioned vacuum space is mainly formed by the interior shield (as well as the interior
space of the bellows in some embodiments).
[0026] According to another aspect of the invention, a vacuum circuit breaker is provided
which comprises at least one vacuum interrupter according to the invention. It should be
appreciated by the person skilled in the art that in addition to the vacuum interrupter according
to the invention, the vacuum circuit breaker according to the present invention may have any
suitable vacuum circuit breaker components known in the prior art or developed in the future.
In other words, the vacuum interrupter according to the invention may be employed in the
vacuum circuit breaker known in the prior art or developed in the future, in order to replace its
vacuum interrupter, which fall within the scope of the invention.
W02014/090089 PCT/CN2013/088030
[0027] Parts of other features and advantages of the present invention will be illustrated in
the below description with reference to the accompanying drawings, and other parts will be
apparent to the persons skilled in the art after reading the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The embodiments of the invention will be described in detail with reference to the
accompanying drawings, in which:
FIG 1 illustrates the vacuum interrupter according to the first embodiment of the invention;
FIG 2a and FIG 2b illustrate the vacuum interrupter according to the second embodiment
of the invention;
FIG 3a illustrates the flexible electrical connection feature according to an embodiment
of the invention, when the movable contact engages with the fixed contact;
FIG 3b illustrates the flexible electrical connection feature of FIG 3a when the movable contact
disengages f?om the fixed contact;
FIG 4a illustrates the components of the vacuum interrupter of FIG 2, when the movable
contact engages with the fixed contact;
FIG 4b illustrate sthe relative positions of the components of FIG 4a when the movable
contact disengages h m the fixed contact;
FIG 5 is the detailed view of FIG 4b, specifically showing the switching-on conductive
feature according to one embodiment of the invention; and
FIG 6 illustrates the separating support according to one embodiment of the invention.
In the present invention, the same reference numerals represent the same or similar
features or components.
DETAILED DESCRIPTION OFTHE EMBODIMENTS
[0029] The embodiments of the invention will be further described in the following detailed
description with reference to the accompanying drawings. Although the drawings are provided
for the purpose of illustrating the particular embodiments of the invention, it is not necessary to
present the drawings in scale, in which some features may be exaggerated, removed or
sectioned in order to better illustrate the invention.
[0030] Refening to Fig.1, showing a vacuum intermpter 100 according to the first
embodiment of the invention. The vacuum interrupter 100 may comprise a housing 1, a fixed
contact4 and movable contact5 mounted within the housing 1. As illustrated, the vacuum
intermpter lOOmay fixther comprise a fixed contact conductive rod 2 which is in rigid
connection with the fixed contact. The fixed contact conductive rod may be connected to a
corresponding electrical element as is disclosed in the art, in such way current transfer is
realized during switching on of the fixed contact 4 and the movable contact5 as well as the
early stage of switching off of the fixed contact 4 and the movable contact 5(i.e., when the
electrical arc has not been cut off).
[0031] The fixed contact 4, the movable contact 5 and the fixed contact conductive rod (or
referred to as "fixed conductive rod") 2 may function and/or move in a manner known in the art.
As an example, the fixed contact and the fixed conductive rod are of static, while the movable
contact moves in its axial direction so as to engage with the fixed contact (switching on) or
disengage fiom the fixed contact (switching off). As mentioned above, at the early stage of
switching on, the breakdown occurs across the air between the movable contact and the fixed
wntact(sepmted distance)such that electrical arc is generated. The electrical arc will decrease
gradually as the contact separation increases, and thus will be extinguished at the end. Although
not specifically indicated in the invention, the fixed contact 4, the movable contact 5and the
fixed contact conductive rod 2may be in any known or other suitable form and/or may be made
of any known or other suitable material. For example, they may all be made of copper, although
they may be made of any other same or different materials. Moreover, the fixed contact 4 and
movable contact 5 may be provided with some given functional structures and features so as to
achieve the given technical effects. For example, the fixed contact 4 and the movable contact 5
may be in form of a disk contact, although they may be other kinds of contact member. The
fixed contact and the movable contact may both be equipped with spiral grooves for prolonging
the current path, such that the cut-off (switching-off) magnet field can be enhanced.
[0032] As mentioned above, the invention is directed to the improvement of the movable
components of the vacuum interrupter, while the overall configuration and functionality of a
vacuum interrupter is known in the art. Therefore, it would be appreciated by the person skilled
in the art that the embodiments of the invention may be combined with some other components
of the vacuum interrupter in the art in a manner that no inconsistence occurs, or some
conventional components as described herein may be suitably replaced with the corresponding
components in the art, so as to yield new embodiments.
[0033] Still referring to Fig.1, the movable components (i.e. the components related to the
movable contact) of the vacuum interrupter according to an embodiment of the invention will
be discussed below in detail.
[0034] As mentioned above, to move the movable contact, the prior art vacuum interrupter
just utilizes a movable contact conductive rod in rigid and electrical connection with the
movable contact, and then the movable contact conductive rod (or referred to as "movable
conductive rod") is connected to a corresponding electrical element Buch as a terminal or the
like, to create current path. Therefore, the movable contact conductive rod in the prior art may
move the movable contact in axial direction to engage with or disengage from the fixed contact.
The use of such a movable conductive rod has to be compromised in maximizing the surface
area for heat dissipation and in minimizing the mass of movable components.
[0035] To this end, the invention provides an arrangement of improved movable components
(the components on the movable contact side). As illustrated in Fig.1, the vacuum interrupter
may also comprise an operating rod 13 rigidly connected to the back side of the movable
contact, a movable contact conductive seat 12fixedly mounted in the housing 1, and a flexible
(soft)electrical connection feature between the movable contact Sand the movable contact
W020141090089 PCTICNZOI 31088030
conductive seat 12. As illustrated in Fig.1, the movable contact conductive seat 12 is in the
form of a hollow member with a central through-hole20, through which the elongated operating
rod 13 passes and is connected to the movable contact 5.Although not illustrated in the figures,
it would be appreciated by the person skilled in the art that in addition to the operating rod 13,
the vacuum interrupter 100 may also comprise an actuator for actuating the operating rod to
move together with the movable contact in the axial direction. As illustrated in the figures, the
movable contact 5, the movable contact conductive seat 12and the operating rod 13 may be
aligned substantially coaxially.
[0036] According to the disclosure, it would be appreciated by the person skilled in the art
that the operating rod 13 may function as operating and thus moving the movable contact, as is
the known movable conductive rod, while the movable contact conductive seat 12 may function
as providing a current path through the movable contact, the conductive seat and other
elecbical elements at least during the disengagement of the fixed contact 4 and the movable
contact 5.The movable contact conductive seat 12also forms a surface for heat dissipation of
the switching-off current. As compared with the prior art, The operating rod 13 of the
disclosure may be made of a wider variety of materials and has a higher degree of freedom in
selection of its dimension and mass more, as long as the operating rod 13 which is in rigid
connection with the movable contact 5 has sufficient strength to withstand the force produced
during the engagement and disengagement of the fixed contact and the movable contact (such
as during the life time). Also, the operating rod may for example use the lighter andlor cheaper
materials, although the material same as that of the moveable conductive rod in the art may also
be possible. Furthermore, the operating rod may have a smaller size.
[0037] Accordingly, the movable contact conductive seat 12 which forms at least part of the
(main) current path during the switching off (i.e., when the movable contact moves and
disengages from the fixed contact) may need not to make much consideration in its moving
mass, such that it may be made bigger with a lager heat dissipation surface and thus a better
heat dissipation effect. Since the movable contact conductive seat 12 performs the conductive
function similar to the known conductive at least during the switching off, the conductive
seat12 may have or consist of the same material such as copper as the known conductive rod,
although any suitable conductive materials may be utilized.
W020141090089 PCTICN20131088030
[0038] In the embodiments illustrated in Fig.1, the conductive path between the movable
contact conductive seat 12 and the movable contact 5is provided by a flexible electrical
connection feature at least during the switching off. As illustrated in the area A of Fig.1, the
flexible electrical connection feature may comprise a plurality of conductive strips 6, one ends
of which are connected to the back side of the movable contact 5, and the other ends are
connected to the top side of the conductive seat 12, such that the conductive strips are arranged
in the space between the movable contact Sand the conductive seat 12, as discussed below in
detail.
[0039] Bearing the teaching of the invention in mind, the person skilled in the art may
conceive of different kinds of flexible electrical connection feature, as long as it allows the
movement of the movable contact relative to the conductive seat and at the same time
maintains the (conductive) connection between the movable contact and the conductive seat.
The flexible electrical connection feature may use various suitable conductive materials,
including those same as or different from that of the fixed contact, the movable contact, fixed
conductive rod or conductive seat, such as strips made of soft copper.
[0040] In the embodiment of Fig.1, the flexible electrical connection feature constitutes a
part of the main current path during both the switching on and the switching off of the fixed
contact 4 and the movable contact 5, such that the current of the fixed contact 4 flows
substantially through the flexible electrical connection feature to the conductive seat 12. In
some other embodiments of the invention, however, the main current path 26 during switching
on will not pass through the flexible electrical connection feature which will physically connect
the movable contact with the conductive seat all the time, as discussed below in detail.
[0041] Referring to Fig.3a and Fig. 3b, a preferred embodiment of the flexible electrical
connection feature as shown in the area A of the Fig.1 will be discussed below. Fig.3a and Fig.
3b are schematicvies of the area A of Fig.1, and therefore the components of the invention are
not necessarily configured to have the arrangement, dimension parameters or scale exactly
corresponding to what they illustrate. In the arrangement as shown in Fig. 3% the fixed contact
4 and the movable contact 5 are in engagement with each other, while Fig. 3b illustrates that the
fixed contact 4 and the movable contact 5 disengage £torn each other. As shown in Fig. 3a and
WO20141090089 PCTlCN20131088030
Fig.1, a plurality of conductive strips 6 are arranged helically in a consistent helical direction
(counter clockwise from the movable contact to the conductive seat as viewed from the top of
the movable contact) about the axis of the movable contact-i.e., the axis of the conductive seat
or the operating rod, and have the same or substantially the same helical angle a. As the
movable contact 5 disengages and moves away from the fixed contact 4 in the axial direction,
the helical angle a will decease accordingly, as shown in Fig. 3b.
[OM21 As an explanation but not constituting limitation, the inventor finds that in the known
vacuum interrupter, as the separated distance of the fixed contact and the movable contact
increases, the longitudinally magnetic field generated by the current will decrease accordingly,
degrading the cut-off ability, as mentioned above. As the helical angle a of the flexible
conductive strips according to the invention decreases, the horizontal component of a given
current intensity will increase, so as to generate a stronger longitudinally magnetic field.
Therefore, the arrangement in the disclosure is able to reduce or even eliminate the degradation
of the magnet field and thus the decrease of the cut-off ability caused by the increase of the
separated distance, such that a relatively great longitudinal magnet field can be provided even
as the separated distance increases. Therefore, such arrangement in the disclosure will have a
positive effect on the magnet field and the cut-off ability of the vacuum intermpter.
[OM31 In the disclosure, the abovementioned helical angle may be measured in a projection
developed plane of the cylindrical surface which has the longitudinal axis of the movable
contact as the center line , and may be determined by the included angle between the flexible
conductive strips 6 and a plane perpendicular to the said longitudinal axis (i.e., a horizontal
plane in the illustrated embodiment and in the embodiments in which the vacuum intermpter is
vertically oriented). In some other embodiments of the invention, however, the flexible
conductive strips are arranged obliquely between the movable contact and the conductive seat,
such that as the movable contact disengages and moves away from the fixed contact, the
inclined angle, which is determined by the inclined angle of the flexible conductive strips
relative to the above-mentioned plane (such as the horizontal plane), will decrease accordingly.
[0044] In this case, it should be appreciated by the person skilled in the art that the decrease
of the helical or inclined angle means that as the movable contact moves away from the fixed
W020141090089 PCTICN20131088030
contact, the overall angle of the flexible conductive strip, rather than every helical or inclined
angle at each point of the flexible conductive strip 6, will decrease (it is can be seen from Fig.
3b that the overall angle decreases rather than the angles at each point decrease)& should be
appreciated by the person skilled in the art that in some embodiments of the invention,
especially in engineering practice, as the movable contact moves away from the fixed contact,
the flexible conductive strips 6 may not present a perfect helical arrangement or a perfect
inclined arrangement, nor have an ideally helical or inclined angle decrease, but rather they
may assume a combination of the helical and inclined arrangements.
[0045] Based on the geometry theory, as an explanation but not constituting limitation, as the
movable contact moves away fiom the fixed contact in the axial direction, in the helical and/or
inclined flexible conductive strips the vertical component (axial component) of the vector of
the current flowing through the flexible conductive strips will decrease accordingly, while the
horizontal component will increase or remain substantively unchanged. Thus the ratio of the
vertical component to the horizontal component (the tangent value of the helical andlor inclined
angle) will decrease accordingly, such that in general the helical angle or the inclined angle or
their combination will tend to decrease, such that the horizontal component of the current will
increase accordingly, producing a positive effect on reducing the degradation of the magnet
field or enhancing the magnet field. Therefore, any helical arrangement, inclined arrangement
or their combination of the flexible conductive strips will fall within the scope of the invention,
as long as the helical or inclined arrangement may lead to the said angle decrease which in turn
produces the positive effect on the magnet field accordingly.
[0046] In view of these, it should be appreciated by the person skilled in the art that the
flexible conductive "strips" of the invention may have various dimensions, configurations and
shapes as desired, and may be inform of cables, tapes and threads, as long as they are able to
realize the effects of the invention. The various kinds of flexible conductive strips fall within
the scope of the invention.
[0047] In a preferred embodiment of the invention, the flexible conductive strips are evenly
arranged about the movable contact or the operating rod, so as to provide a homogeneous
combustion of electrical arc on the movable contact and improve the efficiency of the contact.
WO20141090089 PCT1CN20131088030
[0048] Referring to Fig.], in some prefened embodiments of the invention, a separating
support 7 is provided, for facilitating the functionality of the plurality of flexible conductive
strips 6. In the embodiments of the invention, the separating support 7 is configured to separate
at least some, or preferably all, of the flexible conductive strips 6 from each other. It is
preferred that the separating support 7 is spaced from the conductive seat 12, or has an electric
resistance significantly greater than that of the flexible conductive strips and the conductive
seat. In an example, the separating support 7 is of a stainless steel member.
[0049] In some embodiments, the separating support 7 is configured such that at least during
switching off it will not transfer significant current which will he otherwise detrimental to the
performance of the flexible conductive strips. In the illustrated embodiments, the separating
support 7 is fixed onto the operating rod 13,although the separating support may be fixed to
other components, as long as it is able to advantageously separate the, e.g., adjacent, flexible
conductive strips from each other. It should be understood that the separating support discussed
in other parts of the specification may be replaceably combined in various embodiments of the
invention and mounted onto various suitable components.
[0050] As illustrated in Fig.1, according to an advantageous arrangement of the invention,
the central through-hole 20 of the hollow conductive seat 12 defines a receiving groove 19,
which may receive not only a portion of the operating rod but also some other components of
the vacuum interrupter 100, such that a compact vacuum interrupter is made. In the
embodiment illustrated inFig.l,the conductive seat 12 forms a first opening portion 17 adjacent
to the top portion thereof, which has a radial dimension smaller than that of the receiving
groove and is in communication with the receiving groove 19, as discussed below in detail.
[0051] The embodiment of Fig.1 particularly shows a preferred configuration of bellows,
although it should be appreciated by the person skilled in the art that the prior art bellows and
its configuration may be combined in the embodiments of the invention to yield new
embodiments. In the embodiment, the bellows 10 is configured to peripherally seal around the
operating rod 13. More specifically, the operating rod 13 has a stopping portion15 extending
from the rod body therefore, with a first end of the bellows being sealingly connected to the
stopping portion15 (bellows).Contrary to the prior art arrangement which seals around the
WO2014/090089 PCT/CN2013/088030
housing opening for the moveable conductive rod, a second end of the bellows loin the
embodiment peripherally seals around the central through-hole 20 of the conductive seat 12.
More specifically, the second end surrounds the top opening portion 17 of the central
through-hole 20 such that a simple installation and sealing are provided. By means of such
sealing of the bellows 10 with the operating rod as well as the conductive seat, formed within
the housing 1 is a vacuum space 25, and the interior of the bellows 10 also constitutes part of
the vacuum space, such that the bellows withstands the atmospheric pressure on its outer side.
In terms of the inherent property of the bellows, such externally pressure-bearing configuration
has longer service life as compared with the prior art configuration which withstands the
atmospheric pressure on its inner side. In addition, at the normal (switching-off) condition of
the vacuum interrupter, the bellows is in compression or contraction. As compared with the
conventional design in the prior art in which the bellows is in stretching or tensional condition,
the compression or contraction of the bellows make it less possible to be damaged, and thus
allows a longer service life.
[0052] The embodiment of Fig.1 particularly shows a preferred configuration of contact
spring, although it should be appreciated by the person skilled in the art that the prior art
contact spring and its configuration may be combined in the embodiments of the invention to
yield new embodiments. In the embodiment of Fig 1, the contact spring means comprises a pair
of nested contact springs 11,11', one ends of which rest against the stopping portion15 and the
other ends rest against a stopping member16 fixed to the housing. The advantage of the
invention lies in that the contact spring which otherwise has to be arranged outside the housing
of the vacuum interrupter in the prior art due to the confined space now may be easily
positioned in the receiving groove 19 of the conductive seat 12 inside the housing 1, such that a
compact arrangement is provided. Accordingly, the bellows in the embodiment of the invention
may also be positioned in the receiving groove 19 inside the housing 1.
[0053] In the embodiment of Fig.1, provided in the central through-hole 20 is also a guiding
bush 14which surrounds the outer periphery of the bellows 10 and a portion of the springs
11,117.The guiding bush 14 facilitates the contraction and stretching of the bellows, and may
also perform the functionalities of protection and guide.
W020141090089 PCTlCN20131088030
[0054] Furthermore, although not illustrated in the embodiments of the invention, any
suitable guiding feature for the movable contact (or the movable conductive rod) which is
known in the prior art or will be developed in hture can be combined in the embodiments of
the invention for guiding the movable contact (or movable conductive rod) of the embodiments
of the invention.
[0055] Now referring to the sectional views of Fig.2a, 2b, 4a and 4b the second embodiment
of the vacuum interrupter 100' of the invention is illustrated. The functions and arrangements of
the components in the embodiment may refer to the first embodiment. Especially the flexible
electrical connection feature may be similar to the plurality of helically flexible conductive
strips in the first embodiment, or it may additionally or alternatively employ other flexible
electrical connection features mentioned above, which all fall within the scope of the invention.
One difference in the second embodiment lies in that the operating rod 13 also comprises a
switching-on conductive feature. In the second embodiment, the switching-on conductive
feature comprises a conductive top portion 22 of the operating rod 13 rod body and a
conductive flange 23 extending from the rod body. Accordingly, the central through-hole 20
forms a first, upper opening portion 17 with a smaller diameter and a second, lower opening
portion 18 with a greater diameter. The second, lower opening portion 18 may be the receiving
groove 19 or constitute a portion of the receiving groove, or the second, lower opening portion
may be fonned separately h m the receiving groove.
[0056] Particularly referring to Fig.4a and 4b, the flange 23 has a diameter corresponding to
that of the first opening portion 17. When the fixed and movable contacts 4,5 switch on, the
flange 23 is in surface contact in the first opening portion 17 with the conductive seat 12. Since
the operating rod 13 locates in the centered position andlor it has a relatively greater cross
profile, a part of, or preferably most of, or more preferably substantially all of, the current flows
from the movable contact to the conductive seat 12 through the switching-on conductive
feature (the top portion 22 and the flange 23) during switching on, while another part of or a
relatively less part of the current flows through the flexible electrical connection feature. It is
more preferred that the main current path 26flows through the switching on conductive feature,
while the current flowing through flexible electrical connection feature may be practically
negligible as compared with that flowing through the switching-on conductive feature.
W02014/090089 PCT/CN20131088030
Therefore, in the embodiment, although the invention advantageously provides many benefits
by means of the flexible conductive feature, this embodiment is further able to provide
comparable or even better current conductive efficiency during switching on by means of the
switching-on conductive feature, as compared with the prior art design. When the fixed and
movable contacts 4, 5 are disengaging (switching ofl) from each other but a complete cut-off
has not yet been realized, i.e. there is an electrical arc 29, as shown in Fig.4b, the flange 23 now
has been moved into the second opening portion 18 with the greater diameter, and thus does not
contact with the conductive seat 12(as detailed in Fig. 5). At this time, the current transfer is
completely or substantially realized by means of the flexible electrical connection feature such
that the main current path 26 now is formed passing through the flexible electrical connection
feature. Since the switching-on conductive feature now is not working, the embodiment now
will still have the advantages produced by the flexible electrical connection feature mentioned
above.
[0057] Although the embodiment illustrates a specific arrangement of the switching-on
conductive feature, the person skilled in the art, bearing the teachings of the invention in mind,
may conceive of various configurations. The above-mentioned top portion andlor flange or any
other suitable switching-on conductive features may comprise, or consist of, any suitable
conductive material, but it is desired that they have an electric conductivity equivalent to, or
preferably better than, the flexible conductive feature. Moreover, it should be understood that
the lower portion 24 of the operating rod 12 may only serve as a part of the rod for actuating
the movement of the moveable contact, and thus may have a material same as or different from
that of the top portion 22 andlor flange 23, such as a material selected according to the
functionality of an operating rod.
[0058] In the second embodiment, an example of another separating support 7 is particularly
illustrated. This separating support 7is mounted onto conductive seat 12, as con& to the
previous embodiment. The separating support 7 has a plurality of circumferentially formed
holes 21, the number of which corresponds to the number of the flexible conductive strips, with
one flexible conductive strip 6 passing through each hole 21. By means of the separating
support, during the movable contact is disengaging from the fixed contact, i.e. when the
flexible conductive strips 6 are being compressed, the flexible conductive strips can be
W020141090089 PCT/CN2013/088030
separated from each other so as not to deteriorate the performance of the flexible conductive
strips, such as the performance of enhancing the magnetic field. It is desired that the separating
support 7 does not or substantially not constitute a current path (such as negligible in the
engineering practice) through which the current flows from the movable contact to the flexible
conductive strips andlor the conductive seat. Preferably, this separating support7 may be
similarly made of e.g., stainless steel and/or mounted electrically separately from the
conductive seat and/or the flexible conductive strips.
[0059] Now refening to Fig.6, another embodiment of the separating support 7' is illustrated,
which is configured to be mounted onto the conductive seat 12 in a way similar with that of the
above-mentioned separating support 7and has through-hole 27 defined by an annular portion
28.The operating rod 13 passes the through-hole. The separating support 7'has a plurality of
radial bars 29 extending radially from the annular portion, such that defined between the radial
bars are spaces, through which the respective flexible conductive strip 6 (not illustrated) passes,
for facilitating the separation of the flexible conductive strips.
[0060] The invention may also comprise various configuration of the separating support.
Furthermore, the features of the separating support 7,7' as shown in Fig.2a,2b and Fig.6 can be
combined in the separating support as shown in Fig.l.For example mounting onto the
conductive seat may be accordingly changed to mounting to the operating rod.
[0061] Referring to Fig.2a and Fig.2b again, in the second embodiment, a bellows bush9 is
provided inside the bellows lofor preventing the electrical arc from burning the bellows which
will otherwise cause a leakage.
[0062] In the embodiment, an interior shield 3 is also provided, which accommodates the
movable contact, the fixed contact, the flexible electrical connection feature and a portion of
the conductive seat under a vacuum condition, and forms the above-mentioned vacuum space
25 together with the internal space of the bellows 10.The shield 3 may be made of any suitable,
known or new, material same as or different from the material of the housing 1. For example,
the housing 1 and/or shield 3 maybe made of ceramic and/or glass.
[0063] Moreover, in this embodiment a different spring arrangement is employed, in which
the spring is a tension spring 11, with its bottom end fixed to the stopping portion15 extending
from the operating rod 13 and it stop end fixed to the stopping member16 that is fixed to the
static components in the housing, such as the conductive seat 12, such that a force for
compressing the operating rod 13 and the movable contact 5 against the fixed contact 4 is
applied. Moreover, various other spring arrangement may be conceivable.
[0064] The above the vacuum intermpter of several embodiments of the invention is
described. It should be noted that a vacuum circuit breaker including the vacuum intermpter
according to the invention also falls within the scope of the invention.
[0065] It should be understood that although the specification is described according to each
embodiment, it does not mean that each embodiment only includes one single aspect of the
invention. The specification described in this way is merely for the purpose of clarity. It should
take the specification as a whole into consideration, such that the technical solutions of various
embodiments may be combined with each other to yield other embodiments which can be
understood by the person skilled in the art.
[0066] It is intended that the above description shall be interpreted as illustrative only and
not limiting. Equivalence, modification, alternation or combination may be made by the person
skilled in the art without departing from the spirit and principle of the invention, and thus fall
within the scope of the invention.
List of Reference Symbols
1-housing, ceramic or glass bush
2-fixedcontact conductive rod
6-flexible (soft) conductive strips
7-separating support
8 - switching-on conductive feature
9-bellows bush
1 0-bellows
11 -contact spring
12-conductive seat
13-operating rod
14-guiding bush
15-stopping portion
16-stopping member
17-first opening portion
18-second opening portion
19-receiving groove
20-centralthrough-hole
21-hole
22-top portion
23-flange
25-vacuum space
26-main current path
27-through-hole
28-annular portion
29-electrical arc
A-area
a -helical angle
100,100'-vacuum interrupter

We claim:
1. A vacuum interrupter (1 00,l OW), comprising:
a housing (1);
a fixed contact (4) received in the housing (1);
a movable contact (5) received in the housing (1) and configured to be movable to
engage with or disengage from the fixed contact (4);
a conductive seat (12) fixedly mounted in the housing (1) and configured to maintain an
electrical connection with the movable contact (5);
a flexible electrical connection feature received in the housing (1) for connecting the
movable contact (5) with the conductive seat (12); and
an operating mechanism for actuating a movement of the movable contact (5).
2. The vacuum interrupter (100,100') according to claim 1, wherein the conductive seat
(12) is in form of a hollow member with a central through-hole (20), and the operating
mechanism includes an operating rod (13) in rigid connection with the movable contact (5),
and an actuator configured to move at least the operating rod (13) and the movable contact to
disengage from the fixed contact, wherein the operating rod passes through the central
through-hole (20).
3. The vacuum interrupter (100,100') according to claim 1 or 2, wherein the flexible
electrical connection feature includes at least one flexible conductive strip (6) arranged
between the movable contact and the conductive seat, wherein the flexible conductive strip (6)
is arranged inclinedly relative to a longitudinal axis of the movable contact, or helically
around the longitudinal axis.
W02014/090089 PCT/CN20131088030
4. The vacuum interrupter (100,100') according to claim 3, wherein the at least one
flexible conductive strip (6) includes a plurality of flexible conductive strips (6).
5. The vacuum interrupter (100,100') according to claim 4, wherein the plurality of
flexible conductive strips (6) have a consistent inclined or helical direction.
6. The vacuum interrupter (100,100') according to claim 2, wherein the operating rod
comprises a switching-on conductive feature in contact or connection with the movable
contact, wherein the switching-on conductive feature is configured to electrically connect with
the conductive seat when the movable contact engages with the fixed contact, and to
electrically disconnect or be separated from the conductive seat when the movable contact
disengages from the fixed contact.
7. The vacuum interrupter (100,100') according to claim 6, wherein the central
through-hole of the conductive seat comprises a first opening portion (17) with a smaller
diameter and a second opening portion (1 8) with a greater diameter, wherein the switching-on
conductive feature includes a flange (23) which has a shape at least partially corresponding to
the first opening portion (1 7), and the flange is configured to be positioned in the first opening
portion (17) when the movable contact engages with the fixed contact and moved into the
second opening portion (18) when the movable contact disengages the fixed contact.
8. The vacuum interrupter (100,100') according to claim 4, wherein the vacuum
interrupter (100,100') further includes a separating support (7,7') for supporting and
separating at least some of the plurality of flexible conductive strips (6).
9. The vacuum interrupter (100,100') according to claim 8, wherein the separating
support (7) has a plurality of circumferentially arranged holes (21), one flexible conductive
strip (6) passing through each of the holes (21).
10. The vacuum interrupter (100,100') according to claim 8, wherein the separating
support (7') has a plurality of radially extending radial bars (29), wherein a space (30)s
defined between the two adjacent radial bars, one flexible conductive strip (6) passing through
each space.
11. The vacuum interrupter (100,100') according to any one of claims 8-10, wherein the
separating support (7,7') is mounted onto or integral with the conductive seat (12) or the
operating rod (13).
12. The vacuum interrupter (100,100') according to claim 2, further comprising a bellows
(lo), one end of which is in peripherally sealing connection with the operating rod (13), and
the other end is in peripherally sealing connection with the central through-hole (20) to define
a vacuum space (25) within the housing (I), wherein the interior of the bellows (10) is in
vacuum.
13. The vacuum interrupter (100,100') according to claim 12, wherein a bellows bush (9)
is provided inside the bellows (10).
14. The vacuum interrupter (100,100') according to claim 2, further comprising a contact
spring (1 1,ll') for biasing the movable contact towards the fixed contact, wherein one end of
the contact spring (1 1 ,I 1') is mounted to the operating rod (13) and the other end is mounted
to a fixed part within the housing (I).
15. The vacuum interrupter (1 00,100') according to any one of claims 12-1 4, wherein the
conductive seat (12) defines a receiving groove (19) for receiving the bellows (10) and/or the
spring (lI,ll7).
16. The vacuum interrupter (100,100') according to claim 1 or 2, further comprising an
interior shield (3) positioned inside the housing (I), wherein the interior shield (3) receives the
fixed contact (4), the movable contact (5), the flexible electrical connection feature and a
portion of the conductive seat (12) under a vacuum condition.
17. A vacuum circuit breaker including the vacuum interrupter (100,100') of the any one
of the claims 1-16.