Multistage fuse

The present invention relates to a multistage fuse, and more particularly, to a multistage fuse including: a fuse module including a first fuse bar formed in a bar shape as a conductive member; a melted portion which supports the first fuse bar and is melted when overcurrent flows; and a second fuse bar which supports the melted portion; and a contact terminal which contacts the first fuse bar by elastic force, in which when the overcurrent flows on the melted portion, the melted portion is melted to disconnect the first fuse bar and the contact terminal.

TECHNICAL FIELD

This application claims priority to and the benefit under 35 U.S.C. § 119 of Korean Patent Application No. 10-2016-0086841 filed in the Korean Intellectual Property Office on Jul. 8, 2016, and under 35 U.S.C. § 365 to PCT/KR2017/007207 filed on Jul. 6, 2017, the entire contents of which are incorporated herein by reference.

The present invention relates to a multistage fuse, and more particularly, to a multistage fuse including: a fuse module including a first fuse bar formed in a bar shape as a conductive member; a meltable portion which supports the first fuse bar and is melted when overcurrent flows; and a second fuse bar which supports the meltable portion; and a contact terminal which contacts the first fuse bar by elastic force, so that even if any one fuse module is fused due to temporary overcurrent and the current is thus momentarily interrupted, the system can be continuously used by using the other fuse module without replacing the fuse.

BACKGROUND

A fuse as a device that serves to protect a circuit or system by blocking overcurrent is widely used in most circuits for circuit protection for preventing secondary damage such as or fire. In general, the fuse has its unique rated current capacity, and the rated current capacity is determined by a metal component constituting the fuse.

However, the fuse in the related art is fused by only transient surge current to interrupt current, so that a whole system can not be used until the fuse is replaced by interrupting the current. For example, if the overcurrent occurs in a battery system of an electric vehicle, and the fuse is fused, there is inconvenience that an automobile can not be used until the fuse is replaced at an auto shop. In addition, since one rated current capacity is determined for each fuse, it is impossible to limit the current at various levels according to the need of a user and a purpose or use of the system.

Therefore, there is a growing need for researching fuses that have various rated current capacities and can perform overcurrent interruption operations several times.

SUMMARY

In order to solve the problem and an object of the present invention is to provide a multistage fuse which includes: a fuse module including a first fuse bar formed in a bar shape as a conductive member; a meltable portion which supports the first fuse bar and is melted when overcurrent flows; and a second fuse bar which supports the meltable portion; and a contact terminal which contacts the first fuse bar by elastic force and which allows each fuse module to have various rated current capacities to secure stepwise stability of a system and perform overcurrent interruption several times.

A multistage fuse according to an embodiment of the present invention may include: a fuse module including a first fuse bar formed in a bar shape as a conductive member; a meltable portion which supports the first fuse bar and is melted when overcurrent flows; and a second fuse bar which supports the meltable portion; and a contact terminal which contacts the first fuse bar by elastic force, in which when the overcurrent flows on the meltable portion, the meltable portion is melted to disconnect the first fuse bar and the contact terminal.

In the multistage fuse, the number of fuse modules may be 2 or more.

In the fuse module, respective fuse modules may have different rated capacities of the meltable portions.

The contact terminal may include a contact tip formed by the conductive member and contacting the first fuse bar, and an elastic member pushing the contact tip in the direction of the first fuse bar.

The contact tip may be formed in a cylindrical shape, and the contact terminal may further include a contact support unit accommodating a part of the contact tip therein.

A conductive circuit contacting the contact tip may be formed in an inner portion of the contact support unit and an outer portion of the contact support unit may be formed by a non-conductive member.

According to an embodiment of the present invention, even if any one fuse module is fused due to temporary overcurrent and the current is thus momentarily interrupted, a system can be continuously used by using the other fuse module without replacing the fuse and rated current levels of respective fuse modules can be variously set for the need of a user or efficient driving of the system.

DETAILED DESCRIPTION

The present invention will be described below in detail with reference to the accompanying drawings. Herein, the repeated description and the detailed description of publicly-known function and configuration that may make the gist of the present invention unnecessarily ambiguous will be omitted. Embodiments of the present invention are provided for more completely describing the present invention to those skilled in the art. Accordingly, shapes, sizes, and the like of elements in the drawings may be exaggerated for clearer explanation.

Throughout the specification, unless explicitly described to the contrary, a case where any part “includes” any component will be understood to imply the inclusion of stated components but not the exclusion of any other component.

In addition, the term “unit” disclosed in the specification means a unit that processes at least one function or operation, and the unit may be implemented by hardware or software or a combination of hardware and software.

FIG. 1is a diagram schematically illustrating a multistage fuse according to an embodiment of the present invention.

Referring toFIG. 1, the multistage fuse1000according to the embodiment of the present invention may include a fuse module100and a contact terminal200.

The fuse module100may include a first fuse bar110, a meltable portion120, and a second fuse bar130.

The first fuse bar110may be formed in a bar shape as a conductive member. The first fuse bar110is in direct contact with the contact terminal200to be described later and serves to allow current to flow between the second fuse bar and the contact terminal to be described later.

The meltable portion120may be a member that is melted when overcurrent flows. In general, a rated capacity of a fuse is determined according to physical characteristics of the meltable portion120. The meltable portion120may serve to support the first fuse bar110before the overcurrent flows. However, since the meltable portion120is melted when the overcurrent flows, the meltable portion120may not serve to support the first fuse bar110. Therefore, when the overcurrent flows to the meltable portion120, the meltable portion120is melted, and as a result, the contact between the first fuse bar110and the contact terminal200is broken.

The number of fuse modules100may be 2 or more. The existing fuse is fused (melted) by temporary overcurrent, and as a result, a entire system connected with the fuse may not be used. However, in the multistage fuse according to the embodiment of the present invention, even if any one fuse module100is fused due to the temporary overcurrent and current is thus interrupted, the system may be continuously used by using the other fuse module100without replacing the fuse. In the multistage fuse according to the embodiment of the present invention, when fusing occurs due to the overcurrent, the current is momentarily interrupted and the entire system may be stopped by recognizing the current interruption by a battery control system (for example, BMS). Thereafter, when a user presses a reset button again, the system is restarted, and as a result, repetitive replacement of the fuse is minimized while maintaining an inherent function of the fuse by restarting the system, thereby preventing the system from being unnecessarily interrupted.

In the fuse module100, respective fuse modules100may have different rated capacities of the fused portions120. When the fuse module100(hereinafter referred to as a “first fuse module100(a)”) which is first connected with the contact terminal200, the fuse module100(hereinafter, referred to as a “second fuse module100(b)”) which is connected with the contact terminal200when the first fuse module100(a) is fused, and the fuse module100(hereinafter, referred to as a “third fuse module100(c)”) connected with the contact terminal200when the second fuse module100(b) is fused may be different from each other in rated capacity of the meltable portion120. In this case, rated current levels of the respective fuse modules100may be variously set for the need of the user or efficient driving of the system.

FIGS. 2 and 3are diagrams schematically illustrating a state in which meltable portions120of some fuse modules100of the multistage fuse according to the embodiment of the present invention are melted andFIG. 4is a diagram schematically illustrating a contact terminal200of the multistage fuse according to the embodiment of the present invention.

For example, if the first fuse module100(a) sets the rated current capacity to 100 A, the second fuse module100(b) sets the rated current capacity to 150 A, and the second fuse module100(b) sets the rated current capacity to 200 A, when overcurrent of 100 A or more flows on the multistage fuse, the first fuse module100(a) is fused and the contact terminal200is disconnected from the first module100(a), and as a result, the current is interrupted and thereafter, the contact terminal200contacts the first fuse bar110of the second fuse module100(b), and as a result, the current may flow on the system again as illustrated inFIG. 2. In this case, once the current is interrupted by a control unit of the system, it is preferable that the system is operated again only when the user inputs a reset signal by pressing a reset button. Thereafter, when the overcurrent of 150 A or more flows on the multistage fuse again, the second fuse module100(b) is fused and the contact terminal200is disconnected from the second fuse module100(b), and as a result, the current is interrupted and thereafter, the contact terminal200contacts the first fuse bar110of the third fuse module100(c), and as a result, the current may flow on the system again as illustrated inFIG. 3.

When current of 200 A or more flows, the system is finally interrupted. Therefore, it is possible to continuously drive the system by minimizing the fuse replacement while ensuring the stability of the system step by step according to the need of the user or the purpose and usage of the system.

The second fuse bar130may serve to support the meltable portion120. The second fuse bar130may be made of the same material as the first fuse bar110, but may be made of another material. The second fuse bar130may be connected to another wire (not illustrated) or circuit (not illustrated) to allow the current to flow on the multistage fuse.

The contact terminal200may contact the first fuse bar110by elastic force. More specifically, the contact terminal200may include a contact tip210and an elastic member.

The contact tip210may be formed of a conductive member on which the current may flow and may contact the first fuse bar110. The shape of the contact tip210is not particularly limited, but it is preferable that one portion of the contact tip210is formed in a long shape so that a part of the contact tip210may be accommodated in a contact support to be described later. As one example, the contact tip210may be formed in a cylindrical shape.

The elastic member is a member having the elastic force due to a change in length, and may serve to push the contact tip210in the direction of the first fuse bar110. For example, the elastic member may be a spring230.

The contact terminal200may further include a contact support unit220accommodating a part of the contact tip210therein. The contact support unit220may serve to guide movement of the contact tip210by the elastic member. For example, when the contact tip210is formed in the cylindrical shape, the contact support unit220is formed in the cylindrical shape to guide the contact tip210to move in the direction of the first fuse bar110by the elastic member. Further, the contact support unit220may be formed of two or more members. The contact support unit220may be formed in a multistage structure including two or more members. For example, as illustrated inFIGS. 1 to 4, the contact support unit220may be formed in a shape in which cylinders having different diameters are overlapped.

Referring toFIG. 4, the contact support unit220may include conductive circuits222and224which contact the contact tip210therein. The conductive circuits222and224may serve to allow the current to flow in connection with another wire (not illustrated) through contact with the contact tip210. When the contact support unit220is formed in the multistage structure including two or more members, the contact support unit220may include a connection tip225connecting conductive circuits of the respective members.

Further, an outer portion of the contact support unit220may be formed by non-conductive members221and223. When the meltable portion(s)120of the first fuse module100(a) and/or the second fuse module100(b) is(are) melted, it may be difficult that the first fuse bar110may be bent accurately in an orthogonal direction to the second fuse bar130. Therefore, the outer portion of the contact support unit220is formed by the non-conductive member to prevent the first fuse bar(s)110of the melted first fuse module100(a) and/or the second fuse module100(b) and the contact tip210from abnormally contacting each other.

Hereinabove, a specific embodiment of the present invention has been illustrated and described, but the technical spirit of the present invention is not limited to the accompanying drawings and the described contents and it is apparent to those skilled in the art that various modifications of the present invention can be made within the scope without departing from the spirit of the present invention and it will be regarded that the modifications are included in the claims of the present invention without departing from the spirit of the present invention.