阅读说明：本技术 致动器 (Actuator ) 是由 山本裕三 宫下高利 于 2018-06-28 设计创作，主要内容包括：一种通过火药的燃烧而被驱动的致动器(1),其将用于驱动输出部分的能量令人满意地传递给输出部分。输出活塞部分(6)具有接收驱动能量的特定端面。密封构件(8)将燃烧产物限制在由密封构件分隔的第一空间(34)中。密封构件具有固定端部(35)和与特定端面接触的接触部(34)。在点火器(20)中的火药燃烧前的状态下,接触部(34)位于初始位置处。随着点火器(20)内的火药的燃烧,接触部(34)在与特定的端部(6a)接触的同时随着输出活塞部分(6)的滑动运动而移动到操作位置。(An actuator (1) driven by combustion of gunpowder satisfactorily transmits energy for driving an output portion to the output portion. The output piston portion (6) has a specific end surface that receives driving energy. The sealing member (8) confines the combustion products in a first space (34) separated by the sealing member. The seal member has a fixed end portion (35) and a contact portion (34) that contacts a specific end surface. In a state before ignition of gunpowder in the igniter (20), the contact portion (34) is located at an initial position. The contact portion (34) moves to the operating position with the sliding motion of the output piston portion (6) while contacting the specific end portion (6 a) with the combustion of the powder in the igniter (20).)

1. An actuator including an actuator main body including a through hole extending in an axial direction thereof, and an output piston portion provided slidably in the through hole and adapted to apply a certain force to a target object by projecting the output piston portion from an output surface of the actuator main body, the actuator comprising:

an igniter that burns powder charge and applies driving energy for sliding the output piston portion toward the output piston portion by the combustion of the powder charge in the igniter; and

a sealing member that partitions a space in the actuator body into a first space in which the igniter is disposed and a second space in which the output piston portion is disposed, and that restricts combustion products generated by the igniter in the first space,

wherein the output piston portion has an operating end portion that acts on the target object and a specific end portion that includes a specific end face that receives the driving energy,

the seal member has a fixed end portion fixed to an inner wall defining a space in the actuator body, and a contact portion that comes into contact with the specific end face of the specific end portion when the gunpowder is burned in the igniter,

the contact portion is located at an initial position on the igniter side of the fixed end portion in a state before combustion of gunpowder in the igniter, and

in the case where gunpowder in the igniter burns, the contact portion moves to an operation position on the output surface side of the fixed end portion with a sliding motion of the output piston portion while being in contact with the specific end face.

2. The actuator of claim 1, wherein the sealing member is made of an elastomeric material.

3. The actuator according to claim 2, wherein said seal member further has an intermediate portion which extends between said fixed end portion and said contact portion and which covers a side surface of said specific end portion extending in a sliding direction of said output piston portion in a state before combustion of powder charge in said igniter, and with a sliding movement of said output piston portion caused by combustion of powder charge in said igniter, said contact portion moves from said initial position to said operation position while said intermediate portion stretches in said sliding direction.

4. The actuator according to claim 3, wherein an outer diameter of said specific end portion of said output piston portion is smaller than an inner diameter of said through hole, and said intermediate portion is stretched in said sliding direction along an inner wall of said through hole with a sliding movement of said output piston portion caused by combustion of powder charge in said igniter.

5. The actuator according to any one of claims 1 to 4, further comprising an auxiliary piston portion disposed in the first space in such a manner as to be slidable in the through hole and sandwich the contact portion of the seal member with the specific end face of the output piston portion, the auxiliary piston portion comprising: an igniter-side end portion opposite to the igniter, the driving energy being input to the igniter-side end portion; and an output piston side end portion that transmits the driving energy to the specific end surface of the output piston portion through the contact portion.

Technical Field

The present invention relates to an actuator that applies a specific force to a target object through an output piston portion.

Background

Some circuits are provided with circuit breakers that operate to interrupt conduction between devices when an abnormality occurs in a constituent device of the circuit or when an abnormality occurs in a system including the circuit. As such a circuit breaker, a conduction breaker has been developed, which drives a breaking member at a high speed by high-pressure gas to forcibly and physically break a conductor existing between devices. For example, in the technique disclosed in patent document 1, the breaking member is driven by high-pressure gas generated by a gas generator to break a conductor constituting a part of an electric circuit and to eliminate an arc caused between broken ends of the conductor by the breaking. This provides a reliable conduction break.

An actuator that utilizes the energy of the burning of gunpowder for pressurization has also been developed. For example, patent document 2 discloses a technique related to an actuator that drives a control member through a membrane using energy of gunpowder combustion to interrupt a flow of a medium in a fluid passage. In this technique, an elastically deformable membrane sandwiched between a control member and a housing is deformed by the pressure of gunpowder combustion, and a cylinder portion attached to the membrane is moved to drive the control member.

Reference list

Patent document

PTL 1: japanese patent application publication No. 2014-49300;

PTL 2: U.S. patent No. 6397595.

Disclosure of Invention

Technical problem

In order to efficiently use the energy of gunpowder combustion as a power source of an actuator that applies a specific force to a target object, it is necessary to efficiently transmit the generated combustion energy to an output piston of the actuator. In order to achieve this, it is important to confine the combustion products produced by the combustion of the gunpowder in a certain closed space to increase the pressure in the space.

In the case where an elastically deformable membrane is used as in the prior art to separate a space in which the burning of the powder occurs and a space accommodating an output portion (or a control member) of the actuator as the object to be pressurized and transmit the energy of the burning of the powder to the control member by the deformation of the membrane, the membrane is abruptly elastically deformed at the time of the burning. In order to move the control member through the required distance, it is necessary to deform the membrane greatly towards the control member by combustion of the gunpowder. Then, there is a risk that the film may be broken or torn. If the film breaks, the combustion products cannot be confined in the space where combustion occurs, and it is difficult to drive the control member.

The present invention relates to an actuator driven by powder combustion, and has an object to be able to satisfactorily transmit energy to an output portion to drive the output portion.

Solution to the problem

In order to solve the above-described problems, the present invention provides a structure in which a seal member that partitions a space in a main body of an actuator into an igniter side space and an output piston side space is adapted to confine combustion products generated by an igniter in the igniter side space. This structure can suitably increase the pressure in the igniter side space. Further, by the combustion in the igniter, the portion of the sealing member which is in contact with the output piston portion is moved from the initial position on the igniter side of the fixed end portion of the sealing member to the operation position on the output surface side of the fixed end portion. This configuration helps prevent breakage of the sealing member while ensuring a satisfactory large amount of movement of the output piston portion, thereby enabling satisfactory transmission of drive energy to the output piston portion.

Specifically, according to the present invention, there is provided an actuator including an actuator main body including a through hole extending along an axial direction thereof, and an output piston portion provided in a slidable manner in the through hole, and adapted to apply a specific force to an object by causing the output piston portion to protrude from an output surface of the actuator main body. The actuator further includes an igniter that burns powder charge and applies driving energy for sliding the output piston portion toward the output piston portion by the combustion of the powder charge in the igniter, and a sealing member that partitions a space in the actuator body into a first space in which the igniter is disposed and a second space in which the output piston portion is disposed, and confines combustion products generated by the igniter in the first space. The output piston portion has an operating end portion that acts on the target object and a specific end portion that includes a specific end face that receives the driving energy. The seal member has a fixed end portion fixed to an inner wall defining a space in the actuator body, and a contact portion that comes into contact with the specific end face of the specific end portion when gunpowder is burned in the igniter. In a state before the powder charge in the igniter burns, the contact portion is located at an initial position on the igniter side of the fixed end portion. The contact portion moves to an operation position on the output surface side of the fixed end portion with a sliding motion of the output piston portion while being in contact with the specific end surface as a powder charge in the igniter burns.

In the actuator according to the present invention, the space in the actuator main body is partitioned into the first space and the second space by the seal member. This effectively results in the pressure in the first space increasing when the gunpowder burns in the igniter. Further, the contact portion of the seal member is moved from the initial position to the operating position by the driving energy generated by the combustion of the powder charge in the igniter. During this moving process, the contact portion comes into contact with a specific end surface of the output piston portion, so that the output piston portion slides in the through hole. With the sliding movement of the output piston portion, the operating end portion of the output piston portion protrudes from the output surface to apply a certain force to the target object. The specific force is appropriately set for the purpose of applying a force to the target object. For example, to fracture the target object, a specific force is set to the force required to break the target object. As long as the movement of the contact portion of the seal member is caused by the combustion of the gunpowder, various structures may be employed, such as a structure in which the driving energy is directly applied to the output piston portion through the contact portion, or a structure in which the driving energy is first propagated to a gas, a liquid, or a solid and then indirectly applied to the first piston portion through the contact portion.

In the actuator according to the present invention, the igniter that burns the gunpowder may also be configured in a structure that ignites the ignition charge contained in the igniter by the operation of the igniter to generate combustion products of the ignition charge, or in a structure that further burns a known gas generating agent (e.g., a single-base smokeless powder) by the ignition of the ignition charge to generate combustion products of the ignition charge and the gas generating agent. In the actuator according to the present invention, the structure of the igniter is not particularly limited.

When the powder is burned in the igniter, the combustion products are diffused in the first space in the actuator body, and the pressure in the first space is raised to apply the driving energy to the output piston portion. As described above, this energy is used as a power source for driving the output piston portion. Since the actuator according to the present invention is provided with the sealing member, the combustion products are confined in the first space and do not enter the second space. Therefore, the driving energy generated together with the combustion products will not be wastefully dissipated, but rather it is desirable that the driving energy be transferred to the output piston portion. In order to achieve the sealing effect, it is necessary that the sealing member has a suitable degree of resistance to the combustion of the gunpowder. Furthermore, it is undesirable that the provision of the sealing member hinders the transmission of the driving energy to the output piston portion. It is therefore necessary that the sealing member achieves both a satisfactory confinement of the combustion products and a satisfactory transfer of the driving energy to the output piston portion.

To achieve the above object, the sealing member is configured in such a manner that: the contact portion thereof moves from an initial position on the igniter side of the fixed end portion thereof fixed to the inner wall of the space in the actuator main body (in other words, closer to the igniter than the fixed end portion) to an operation position on the output surface side of the fixed end portion (in other words, closer to the output surface than the fixed end portion) while contacting with the specific end surface of the output piston portion. With this configuration, after the gunpowder burns, the seal member is deformed in such a manner that the contact portion is turned inside out with respect to the fixed end portion, thereby pushing the sliding movement of the output piston portion. Therefore, unlike the case of the prior art, the sealing member does not extend in only one direction along with the combustion of the powder. Therefore, the possibility of the sealing member breaking is reduced. Further, with the aforementioned inside-out turned deformation structure, the moving range of the contact portion with the sliding motion of the output piston portion extends from the initial position on the igniter side of the fixed end portion to the operation position on the output surface side of the fixed end portion. This eliminates large deformation of the sealing member while ensuring that the distance of movement of the contact portion is large enough to enable the output piston portion to slide over a sufficient distance for applying a certain force to the target object. Therefore, the sealing member is less likely to be broken. This enables both satisfactory restriction of the combustion products and satisfactory transmission of the drive energy to the output piston portion.

In the actuator according to the present invention, the sealing member may be made of an elastic member. Thus, the seal member can be stretched as the powder charge in the igniter burns, so that the restriction of the combustion products and the compatibility of the transmission of the driving energy to the output piston portion can be improved.

The seal member may further have an intermediate portion that extends between the fixed end portion and the contact portion and that covers a side surface of the specific end portion that extends in the sliding direction of the output piston portion in a state before the powder charge in the igniter burns. Then, with the sliding movement of the output piston portion caused by the combustion of the powder charge in the igniter, the contact portion is moved from the initial position to the operating position while the intermediate portion is stretched in the sliding direction. With this design of the actuator, the contact portion moves as the intermediate portion of the seal member extends in the sliding direction of the output piston portion, while pushing the output piston portion. This provides an additional amount of sliding of the output piston portion corresponding to the amount of extension. Therefore, the driving energy generated by the combustion of the gunpowder is preferably used to push the output piston portion so that the output piston portion can slide a sufficient distance. Further, since the intermediate portion that extends in the sliding direction of the output piston portion is made of an elastic member, the intermediate portion can be elastically extended. Therefore, the sealing member is less likely to be broken.

In the above actuator, the specific end portion of the output piston portion may have an outer diameter smaller than an inner diameter of the through hole. Then, the intermediate portion is stretched in the sliding direction along the inner wall of the through hole in accordance with the sliding movement of the output piston portion caused by the combustion of the powder charge in the igniter. With this feature, the output piston portion is left with a gap in the radial direction of the through hole in the region near the specific end portion. When the contact portion moves with the combustion of the gunpowder, the intermediate portion can be expanded with the gap, thereby enabling the intermediate portion to be smoothly expanded. Therefore, the output piston portion can slide over a sufficient distance, and breakage of the sealing member can be prevented.

The above-described actuator may further include an auxiliary piston portion that is arranged in the first space in such a manner as to be slidable in the through hole and sandwich the contact portion of the seal member with the specific end surface of the output piston portion. The auxiliary piston portion has an igniter-side end portion opposed to the igniter to which the driving energy is input and an output-piston-side end portion that transmits the driving energy to the specific end surface of the output piston portion through the contact portion.

With this configuration of the actuator, the auxiliary piston portion receives the driving energy from the igniter through the ignition-side end portion thereof, and transmits the driving energy to the specific end face of the output piston portion through the contact portion of the sealing member, which is sandwiched between the output piston portion and the auxiliary piston portion, through the other end or the output-piston-side end portion thereof. Therefore, the sealing member does not receive driving energy directly from the igniter, but receives driving energy through the auxiliary piston portion. Therefore, the contact portion is not directly exposed to high-temperature, high-pressure combustion products during the combustion of the powder, and the seal member including the contact portion can be prevented from being broken with improved reliability. Further, since the contact portion is sandwiched between the output piston portion and the auxiliary piston portion, a force for turning the sealing member inside out can be appropriately applied to the sealing member, thereby enabling the output piston portion to smoothly slide.

Advantageous effects of the invention

The present invention can satisfactorily transmit energy to the output portion to drive the output portion in the actuator driven by the combustion of gunpowder.

Drawings

Fig. 1 is a diagram showing a general configuration of an actuator according to a first embodiment of the present invention.

Fig. 2 is a view specifically showing a piston of the actuator shown in fig. 1.

Fig. 3 is a view showing a basic structure of an initiator (or igniter) attached to the actuator shown in fig. 1.

Fig. 4 is a diagram showing a comparison of a state in which the actuator shown in fig. 1 is in a state before the explosive in the initiator burns and a state after the explosive in the initiator burns.

Fig. 5 is a diagram showing a general configuration of a circuit breaker to which an actuator according to a first embodiment of the present invention is applied.

Fig. 6 is a diagram showing a general configuration of an actuator according to a second embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of an actuator according to the present invention will be described with reference to the accompanying drawings. It should be understood that the features of the embodiments will be described for illustrative purposes and the invention is not limited by the features of the described embodiments.

< first embodiment >

Fig. 1 is a cross-sectional view of the actuator 1 taken along an axial direction thereof. The actuator 1 includes an actuator main body 2 constituted by a first housing 3 and a second housing 4. The front end of the actuator main body 2 (i.e., the end of the second housing 4 opposite to the end connected to the first housing 3) is the output side of the actuator 1, i.e., the side on which a certain force is to be applied to the target object located on the side. The first housing 3 and the second housing 4 are fastened together by screws. A combustion chamber 31 is formed inside the first casing 3. The combustion chamber 31 is an internal space extending in the axial direction of the first housing 3. A through hole 37 is formed inside the second housing 4. The through hole 37 is an internal space extending in the axial direction of the second housing 4. The combustion chamber 31 and the through hole 37 are continuously arranged inside the actuator main body 2, and they are partitioned by a seal member 8 which will be described later.

The front end surface of the actuator main body 2 (i.e., the front end surface of the second housing 4) constitutes an output surface 4 b. The output surface 4b is a surface opposite to the target object to which a certain force is to be applied. A metal output piston 6 is provided in a through hole 37 inside the second housing 4 of the actuator body 2. The output piston 6 is held in the through hole 37 in a manner slidable in the through hole 37.

Fig. 2 shows details of the output piston 6 to assist in understanding its positional relationship with the second housing 4. The output piston 6 has a substantially shaft-like shape extending in the axial direction of the through hole 37. The output piston 6 has a first end 6a on the combustion chamber 31 side and a second end 6b on the output surface 4b side, the second end 6b exerting a certain force on the target object. An O-ring 6c is provided around the output piston 6 so as to allow the output piston 6 to smoothly slide in the through hole 37.

In a state in which the explosive powder in the first housing 3 (shown by a broken line in fig. 2) and the second housing 4 are attached together to constitute the actuator body 2 and then serve as an igniter 20 (to be described later) is burned, the first end portion 6a substantially protrudes into the combustion chamber 31 of the first housing 3 and beyond the end face of the fitting portion 4a of the second housing 4 that fits into the combustion chamber 31. The foregoing state will hereinafter be referred to as "pre-combustion state". The diameter d1 of the first end portion 6a is smaller than the diameter d0 of the through hole 37. Therefore, when the output piston 6 slides in the through-hole 37 toward the output surface 4b, a gap is left between the side surface of the first end portion 6a (i.e., the surface of the output piston 6 extending in the axial direction thereof) and the inner surface of the through-hole 37. In the pre-combustion state, the end face of the second end portion 6b is coplanar with the output surface 4b or recessed from the output surface 4b into the through-hole 37. When the actuator 1 is used, the actuator 1 is arranged in such a manner that the output surface 4b is in contact with a target object to which a certain force is to be applied (as shown in fig. 5 which will be described later), and is fixed at that position.

In the pre-combustion state shown in fig. 1, the seal member 8 is attached to an end surface of the fitting portion 4a of the second housing 4, which is a part of the inner wall of the actuator main body 2. Therefore, the seal member 8 made of an elastic material divides the space inside the actuator body 2 into a space (corresponding to a first space according to the present invention) including the combustion chamber 31 on the side of the initiator 20 and a space (corresponding to a second space according to the present invention) including the through hole 37 on the side of the output piston 6, so as to confine combustion products generated by combustion of the explosive powder in the initiator 20 in the combustion chamber 31. Details of the structure of the seal member 8 and its operation when the powder in the initiator 20 is burned will be described later.

An exemplary structure of the initiator 20 will now be described with reference to fig. 3. The initiator 20 is an electric igniter. The initiator 20 has a cup 21 whose surface is covered with an insulating cover. A space is defined inside the cup 21, and an ignition charge 22 is disposed in the space. In this space, a metal head 24 is also provided. A ring-shaped charge table 23 is provided on top of the metal head 24. The charge table 23 holds the ignition charge 22. On the bottom of the ignition charge 22 is arranged a bridge wire 26, the bridge wire 26 electrically connecting one of two conductive pins 28 with the metal head 24. The two conductive pins 28 are fixed to the metal head 24 by an insulator 25 so that the two conductive pins 28 are isolated from each other when no voltage is applied. The opening of the cup 21 from which two conductive pins 28 supported by the insulator 25 protrude is protected by a resin collar 27, wherein the conductive pins 28 have good isolation from each other.

With the above-described structure of the initiator 20, when a voltage is applied between the two conductive pins 28 by an external power source, a current flows through the bridge wire 26 to burn the ignition charge 22. Then, the combustion products generated by the combustion of the ignition charge 22 are ejected from the opening of the charging stand 23. The initiator cap 14 is formed to have a rim-shaped cross section so that the initiator cap 14 is caught or hooked by the outer surface of the initiator 20 and the initiator cap 14 is fixed to the first housing 3 by screws. Accordingly, the initiator 20 is fixed to the first housing 3 by the initiator cap 14, and the initiator 20 is prevented from being detached from the actuator body 2 due to the pressure generated when the initiator 20 is ignited.

Note that the ignition charge 22 used in the actuator 1 is preferably exemplified by the following powder: powder charges comprising Zirconium and Potassium Perchlorate (ZPP), powder charges comprising Titanium Hydride and Potassium Perchlorate (THPP), powder charges comprising titanium perchlorate and potassium perchlorate (TiPP), powder charges comprising Aluminum and Potassium Perchlorate (APP), powder charges comprising Aluminum and Bismuth Oxide (ABO), powder charges comprising aluminum and molybdenum trioxide (AMO), powder charges comprising Aluminum and Copper Oxide (ACO), powder charges comprising aluminum and iron oxide (AFO), and mixtures of some of the foregoing. The nature of these gunpowders is that they generate a high temperature, high pressure plasma in the combustion immediately after ignition, but due to the absence of gaseous components the pressure drops rapidly as the temperature drops to room temperature and the combustion products condense. Gunpowder other than the aforementioned gunpowder may be used as the ignition powder.

In the case shown in fig. 1, the combustion chamber 31 is empty. However, a gas generating agent that is burned by combustion products generated by the combustion of the ignition charge 22 to generate gas may also be provided in the combustion chamber 31. In the case where the gas generating agent is provided in the combustion chamber 31, it may be, for example, a single-base smokeless powder including 98 mass% of nitrocellulose, 0.8 mass% of diphenylamine, 1.2 mass% of potassium sulfate. Alternatively, a gas generating agent used in a gas generator for an airbag or a seatbelt pretensioner may be employed. In the case where such a gas generating agent is additionally used, the rate of decrease in the generated pressure is lower because the gas generated by combustion contains gas components even at room temperature, unlike the case where only the ignition charge 22 is used. By adjusting the size, shape, and particularly the surface shape of the gas generating agent provided in the combustion chamber 31, the combustion completion time, which is much longer than the combustion completion time of the ignition charge 22, can be changed. Therefore, by adjusting the amount, shape, and arrangement of the gas generating agent, the pressure generated in the combustion chamber 31 can be appropriately adjusted.

Now, the seal member 8 in the pre-combustion state will be described specifically. As shown in fig. 1, the seal member 8 is configured to cover the first end portion 6a of the output piston 6 protruding into the combustion chamber 31. More specifically, the seal member 8 includes: a fixed end portion 35 attached to the fitting portion 4a of the second housing 4; a contact portion 34 that is in contact with and arranged to cover an end surface of the first end portion 6 a; and an intermediate portion 36 extending between the contact portion 34 and the fixed end portion 35 to cover a side surface of the first end portion 6 a. Therefore, in a cross section along the axial direction of the actuator 1 shown in fig. 1, the seal member 8 has a U-shape, and the contact portion 34 constituting the "bottom" of the U-shape is located at its initial position which is closer to the initiator 20 than the fixed end portion 35 (or on the left side of the fixed end portion 35 in fig. 1).

Next, the action of the sealing member 8 and the operation of the actuator 1 upon combustion of the ignition charge 22 in the initiator 20 will be described with reference to fig. 4. The upper diagram in fig. 4 shows the configuration of the actuator 1 in a pre-combustion state, and the lower diagram in fig. 4 shows the actuator 1 in a state in which the actuator 1 is operated by combustion of the ignition charge 22. The latter state will be referred to as "operating state" hereinafter. In fig. 4, in order to compare the two states, the positions of the fixed end portions 35 of the seal member 8 in the diagrams showing the pre-combustion state and the operating state are aligned with respect to the axial direction of the actuator 1. A common position of the fixed end 35 between the two states is indicated as a position X0, and a reference line at a position X0 is indicated as a line L0.

As described above, the position of the contact portion 34 in the pre-combustion state is indicated by X1, which is located on the detonator 10 side of the position X0 (in other words, closer to the detonator 20 than it is). The position of the end surface of the second end portion 6b of the output piston 6 in this state is indicated by F1. When the ignition charge 22 is combusted, the combustion products are diffused in the combustion chamber 31, so that the pressure in the combustion chamber 31 is increased. Therefore, pressure is also exerted on the seal member 8. In particular, the pressure that urges the output piston 6 in the direction toward the output surface 4b is the pressure that acts on the output piston 6 through the contact portion 34 of the seal member 8, and therefore, the end surface of the first end portion 6a of the output piston 6 that is in contact with the contact portion 34 is a surface that receives driving energy from the initiator 20.

As described above, the contact portion 34 of the seal member 8 is a portion that transmits the driving energy generated by the combustion of the ignition charge 22 to the output piston 6. Therefore, when the contact portion 34 of the seal member 8 moves toward the output surface 4b, the output piston 6 slides in the through hole 37. Thus, the second end 6b of the output piston 6 protrudes beyond the output surface 4b by an amount that depends on the amount of sliding movement of the output piston 6. Thus, the output piston 6 may exert a certain force on a target object disposed on or near the output surface 4 b. In the operating state in which the sliding of the output piston 6 has been completed, a portion of the output piston 6 abuts a stopper 4c of the second housing 4, which defines a narrowing of the through hole 37 near the output surface 4b, thereby preventing the output piston 6 from sliding out of the through hole 37. The position of the contact portion 34 in this state will be referred to as an operation position, which is indicated by X2. The position X2 is on the output surface 4b side of the position X0. The position of the end face of the second end portion 6b is indicated by F2.

In the actuator 1 as above, during the ignition of the ignition charge 22, the contact portion 34 of the seal member 8 is moved from the initial position X1 assumed in the pre-combustion state to the operation position X2 assumed in the operation state. The distance of this movement of the contact portion 34 (X2-X1) is equal to the distance of the movement of the output piston 6 for applying a certain force (F2-F1). With this movement, the sealing member 8 is deformed in an inside-out manner. The movement distance of the output piston 6 required to apply a specific force is achieved by this inside-out deformation of the sealing member 8. In this inside-out deformation of the sealing member 8, the sealing member 8 does not have to undergo a very large elastic deformation, but this inside-out deformation is effected substantially only by the movement of the intermediate portion 36 and the contact portion 34 of the sealing member 8, in which the fixing end portion 35 is fixed. Even in the case where the contact portion 34 is greatly moved toward the output surface 4b due to the driving energy generated by the combustion of the ignition charge 22 to expand the intermediate portion 36, the intermediate portion 36 is first moved toward the output surface 4b from the state shown in the upper diagram in fig. 4, and then expands with the movement of the contact portion 34. Therefore, the amount of elastic deformation of the intermediate portion 36 can be kept small. Therefore, it is possible to prevent the breakage of the sealing member 8 while ensuring a sufficient moving distance of the output piston 6 for applying a certain force. Therefore, the driving energy generated by the combustion can be satisfactorily transmitted to the output piston 6, so that the actuator 1 can be efficiently operated.

As mentioned above, the diameter d1 of the first end 6a of the output piston 6 is smaller than the inner diameter d0 of the through hole 37. Therefore, when the aforementioned inside-out deformation of the seal member 8 proceeds, the intermediate portion 36 partially enters into the gap between the first end portion 6a and the wall of the through-hole 37, so that the inside-out deformation and the expansion of the intermediate portion 36 can proceed smoothly along the inner wall of the through-hole 37. The contact portion 34 does not necessarily have to be in contact with the end face of the first end portion 6a of the output piston 6 when in the operating position.

(applications)

Fig. 5 shows a circuit breaker 100 as an application of the actuator 1. In the circuit breaker 100, the actuator 1 is fixed to the conductor 50 by means of the housing 62.

When the circuit breaker 100 is set to an electric circuit, the conductor 50 constitutes a part of the electric circuit. The conductor 50 is constituted by a first connector portion 51 and a second connector portion 52 on both ends, and a cut-off portion 53 extending between the connector portions 51, 52. Each of the first connector portion 51 and the second connector portion 52 has a connection hole 51a, 52a for connection with another conductor (e.g., a lead) in the circuit. Although in the illustrative conductor 50 shown in fig. 5, the first contact portion 51, the second contact portion 52, and the cutout portion 53 form a stepped shape, the first contact portion 51, the second contact portion 52, and the cutout portion 53 may alternatively be substantially straight. The cut-off portion 53 is fixed in contact with the output surface 4b of the actuator 1. Therefore, the end surface of the output piston 6 (or the end surface of the second end portion 6 b) in the actuator 1 is opposed to the cut-off portion 53. The conductor 50 arranged in this manner constitutes the target object mentioned in the present embodiment. In particular, the cut-off portion 53 is a portion of the target object to which the actuator 1 will apply a certain force.

In the housing 62, a box-like insulating portion 60 made of plastic is provided at a position opposite to the actuator 1 with the cut-off portion 53 therebetween. The insulating portion has an insulating space 61 therein.

In the circuit breaker 100 configured as above, when the initiator 20 starts operating in response to a specific trigger signal or manual input, the output piston 6 slides as described above to apply a shearing force to the cut-off portion 53 by its kinetic energy, so that the cut-off portion 53 is cut off. Therefore, conduction between the first connector portion 51 and the second connector portion 52 of the conductor 50 constituting a part of the electric circuit equipped with the circuit breaker 100 is interrupted. The cut piece of the cut portion 53 cut by the output piston 6 is received in the insulation space 61 of the insulation portion 60. This may improve the reliability of the aforementioned interruption of the conduction.

As described above, in the circuit breaker 100 employing the actuator 1 according to the present invention, the actuator 1 can be efficiently operated. This is very advantageous for the circuit breaker 100, which needs to reliably achieve interruption of conduction when necessary. Other examples of applications of the actuator 1 include a punching machine for punching holes in a target object.

< second embodiment >

Fig. 6 shows an actuator 1 according to a second embodiment of the invention. In the first embodiment described above, the driving energy generated by the initiator 20 is transmitted to the output piston 6 through the sealing member 8, and the sealing member 8 is directly exposed to the combustion gas. In the second embodiment, the driving energy is first transmitted to the auxiliary piston 60, and then indirectly transmitted to the output piston 6 through the sealing member 8. Thus, the sealing member 8 is prevented from being directly exposed to the combustion products. In this second embodiment, the actuator main body 2 is constituted by a first housing 3A and a second housing 4. In the following description, parts of the second embodiment that are substantially the same as those of the first embodiment will be denoted by the same reference numerals and will not be described in further detail.

The first casing 3A has a combustion chamber 31 formed inside. The combustion chamber 31 is configured in such a manner that combustion products generated by the initiator 20 are diffused therein. An auxiliary piston 60 made of metal is provided in the combustion chamber 31. The auxiliary piston 60 is slidably held in the combustion chamber 31. One end of the auxiliary piston 60 is opposed to the detonator 20, and the other end is arranged to sandwich the contact portion 34 of the seal member 8 with the first end portion 6a of the output piston 6. When the ignition charge 22 is burned by the operation of the initiator 20, driving energy is input to one end of the auxiliary piston 60 opposite to the initiator 20, and then transmitted to the output piston 6 through the contact portion 34 of the seal member 8. Therefore, when the ignition charge 22 is combusted, the output piston 6 slides together with the auxiliary piston 60. In this case, the seal member 8 also undergoes the same inside-out deformation as in the first embodiment described above. In this second embodiment, since the contact portion 34 is sandwiched between the auxiliary piston 60 and the output piston 6, the deformation of the seal member 8 is restricted to a certain direction, so that the inside-out upset deformation can be smoothly performed. In this embodiment, since the driving energy is first input to the auxiliary piston 60, the sealing member 8 is prevented from being directly exposed to the combustion products. This reduces thermal stress on the seal member 8, so that the prevention of cracking thereof can be improved.

As described above, the actuator 1 according to the second embodiment can also be applied to the circuit breaker shown in fig. 5.

< example 1>

We conducted an experiment to verify whether sealing is achieved by the sealing member 8 when gunpowder is burned in the initiator 20 in the actuator 1 according to the first embodiment described above. The rubber material used as the seal member 8 is NBR (nitrile rubber). In operation, tests are performed at different temperatures of the actuator 1 using rubber materials having different hardnesses (or durometers), and the seal member 8 is visually inspected for cracking or the like.

More specifically, the tests were carried out at three different temperatures of the actuator 1, specifically a high temperature (50 ℃), a normal temperature (20 ℃) and a low temperature (0 ℃), using two rubber materials having a hardness of 50 and 70. The peak pressure in the combustion chamber 31 during the combustion of the gunpowder was 30 MPa, and the thickness of the seal member 8 was 1 mm. For each hardness and temperature, the combustion of the explosive in the initiator 20 was performed three times, and the breakage of the seal member 8 was checked, but the breakage was not found in all conditions.

< example 2>

We conducted an experiment to verify whether sealing is achieved by the sealing member 8 when gunpowder is burned in the initiator 20 in the actuator 1 according to the second embodiment described above. The rubber materials used as the seal member 8 are chloroprene and NBR. In operation, the inspections are carried out at different temperatures of the actuator 1, and the breakage or the like of the sealing member 8 is visually inspected.

More specifically, the tests were carried out at three different temperatures (specifically, a high temperature (50 ℃), a normal temperature (20 ℃) and a low temperature (0 ℃) of the actuator 1 using chloroprene having a hardness of 65 and NBR having a hardness of 70 as rubber materials. The peak pressure in the combustion chamber during the combustion of the gunpowder was 30 MPa, and the thickness of the seal member 8 was 1 mm. For each rubber material and temperature, the combustion of the explosive in the initiator 20 was performed three times, and the breakage of the seal member 8 was checked, but the breakage was not found in all conditions.

It will be understood from the above examples that, in both embodiments, NBR may be preferably used as the rubber material of the seal member 8. In the second embodiment, chloroprene may also be used as the material of the seal member 8. The above examples are given by way of example only. Chloroprene may also be used as the rubber material of the seal member in the first embodiment, with the hardness of chloroprene appropriately adjusted and the temperature conditions of the actuator 1 appropriately limited.

List of reference numerals

1: actuator

2: actuator body

6: output piston

8: sealing member

20: detonator

22: ignition powder

31: combustion chamber

34: contact part

35: fixed end part

36: intermediate section

37: through hole

60: auxiliary piston