JP7027263B2 - Two-stage heat switch - Google Patents

Description

The present invention relates to a thermal switch for closing an electric circuit of a device mounted on a high-speed projectile at a predetermined timing by utilizing aerodynamic heating.

For example, in high-speed projectiles such as missiles and observation rockets, in order to make the electrical equipment related to the mission (for example, electrically operated pipes, observation equipment, etc.) operable at a predetermined timing, these A switch is used to close the electric circuit of the device at a predetermined timing.

As one of such switches, a thermal switch using aerodynamic heating received when a high-speed flying object flies in the atmosphere is known.

This heat switch includes a first contact, a second contact pressed toward the first contact by a spring, and a heat detection element interposed between the two contacts, and the first contact is heated to a high temperature by aerodynamic heating. At this time, the heat detection element melts and flows out from between both contacts, and as a result, both contacts come into contact with each other, and the electric circuit having these as contacts is closed (for example, Non-Patent Document 1). reference).

Ballistics Study Group, "Firearms and Ammunition Technology Handbook", Defense Technology Foundation, April 2012, 2012 Revised Edition, p. 582 (Section 3.3.3 (2), Figure 2.4.3-16)

By the way, high-speed projectiles are designed to fly ballistically in the atmosphere (and in some cases in outer space) after being launched from a certain point and then fall to a target point far from the launch point. There is something.

FIG. 3 is a graph showing the time change of aerodynamic heating received by such a long-range high-speed projectile. As shown in the figure, the heating rate by aerodynamic heating has two peaks.

Of these, peak A corresponds to the timing when the heating rate of aerodynamic heating received when the high-speed projectile rises from the launch point into the atmosphere becomes maximum, and peak B corresponds to the atmosphere in which the high-speed projectile heads toward the target point. It corresponds to the timing when the heating rate of aerodynamic heating received when descending inside becomes maximum.

In this way, when the heat switch as described above is adopted for the high-speed projectile in which the heating rate of aerodynamic heating is maximized twice during the mission, the second aerodynamic heating (peak B in FIG. 3) is performed. Even when it is required to close the electric circuit as a trigger, there is a possibility that the electric circuit will be closed at an unintended timing triggered by the first aerodynamic heating (peak A in FIG. 3).

The present invention has been made in view of such a problem, and aerodynamic heating is used for an electric circuit of a device mounted on a high-speed projectile such that aerodynamic heating is maximized twice during a mission. It is an object of the present invention to provide a two-stage thermal switch that can be closed at the timing when the maximum number is reached.

In order to solve the above problems, the two-stage thermal switch according to the first aspect of the present invention has the first contact and the second contact that cooperate with each other to form the contacts of the electric circuit, and the first contact among the first contacts. A state in which a heat detection element fixed to a surface facing the second contact and having a melting point in the operating temperature region is provided, and in an initial state, the second contact and the heat detection element have a gap between them. After the first heat inflow, the second contact and the heat detection element come into contact with each other, and at the time of the second heat inflow, the heat detection element melts and is washed away. The first contact and the second contact come into contact with each other, and the electric circuit is closed.

In order to solve the above problems, the two-stage heat switch according to the second aspect of the present invention is housed in a hollow cylindrical housing and the housing, and the axial length is increased by the inflow of heat to the front end. A telescopic unit whose axial length is reduced by the outflow of heat from the front end, and a position changing unit for changing the axial position of the second contact in the housing are further provided with the first contact and the first contact. The second contact is housed axially side by side in the housing, the first contact is supported by a carrier axially movably housed in the housing, and the carrier is said by a spring. It is pressed in the direction toward the second contact, and in the initial state, it is arranged at a position where there is a gap between the heat detecting element and the second contact, and heat flows into the front end of the telescopic unit. After the length of the telescopic unit increases, heat flows out from the front end and the length of the telescopic unit decreases, so that the position change unit initially positions the axial position of the second contact in the housing. The position in the state is changed to the position in contact with the heat detection element.

In the two-stage thermal switch of the third aspect of the present invention, the telescopic unit has a hollow cylindrical cylinder fixed in the housing and a non-conductive cylinder whose front end is movably inserted into the cylinder. It comprises a columnar shaft made of a sex material, the hydraulic oil is stored in the cylinder, the front end of the shaft is in contact with the hydraulic oil, and heat flows into the front end of the cylinder. As the hydraulic oil expands and the shaft is displaced rearward, the length of the telescopic unit increases, and the hydraulic oil contracts as heat flows out from the front end of the cylinder. By shifting the shaft forward, the length of the telescopic unit is reduced.

In the two-stage thermal switch of the fourth aspect of the present invention, the position change unit is attached so that the pin can protrude radially inward from the inner surface of the housing, and in the initial state, the axial direction of the second contact. A first plunger configured to regulate the movement of the second contact, a second plunger attached so that a pin can protrude radially inward from the inner surface of the second contact, and the second plunger on the outer surface of the shaft. The tip of the pin of the second plunger is in contact with the outer surface of the shaft in the initial state, and is formed of a key groove extending in the axial direction, which is provided at a position in the same phase in the circumferential direction. When the length of the unit increases, the tip of the pin of the second plunger fits into the keyway, and then when the length of the telescopic unit decreases, the tip of the pin of the second plunger fits into the keyway. By engaging with the rear end surface, the axial position of the second contact is changed, and at the same time, the tip of the pin of the first plunger is radially inward behind the second contact. As a result, the axial movement of the second contact is restricted.

According to the present invention, it is required to close the electric circuit of the device mounted on the high-speed projectile such that the aerodynamic heating is maximized twice during the mission at the timing when the aerodynamic heating is maximized for the second time. In this case, it is possible to obtain an excellent effect that the electric circuit is not closed at the timing when the aerodynamic heating is maximized for the first time, and the electric circuit can be surely closed at the timing when the aerodynamic heating is maximized for the second time. can.

It is sectional drawing which shows the schematic structure of the two-stage thermal switch of this invention. It is explanatory drawing which shows the operation mode of the two-stage thermal switch of this invention, (A) is the situation at the timing when aerodynamic heating becomes the maximum at the first time, (B) is the situation at the time when aerodynamic heating becomes the maximum at the first time. After that, the situation up to the timing when the aerodynamic heating reaches the maximum for the second time, (C) the initial situation at the timing when the aerodynamic heating reaches the maximum for the second time, and (D) the situation where the two contacts contact after the situation (C). The situation is shown respectively. It is a graph which shows the time change of aerodynamic heating which a high-speed flying object of a long range receives.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a schematic structure of the two-stage thermal switch of the present invention. The figure shows a state immediately after the two-stage thermal switch is assembled (hereinafter referred to as an initial state).

The two-stage heat switch 1 includes a housing 10, a cylinder 20, a first contact 30, a second contact 40, a heat detection element 50, and a shaft 60 as main components.

The housing 10 is a hollow cylindrical member made of a highly heat-insulating and non-conductive material. The hollow portion is composed of a large-diameter portion surrounded by the front inner wall 10F and a small-diameter portion surrounded by the rear inner wall 10R, and the front inner wall 10F and the rear inner wall 10R are connected by an intermediate inner wall 10M perpendicular to the axial direction. ing.

The cylinder 20 is a member composed of two cylindrical portions having different diameters arranged coaxially and having an open rear end in the axial direction, and includes a large-diameter oil storage portion 22 and a small-diameter shaft guide portion 24. It consists of.

The oil storage portion 22 is a hollow cylindrical portion composed of a front wall 22F, a peripheral wall 22C, and a rear wall 22R, and a circular opening 22A is formed in the center of the rear wall 22R.

The peripheral wall 22C has an outer diameter slightly larger than the inner diameter of the front inner wall 10F of the housing 10, and is tightly fitted to the front inner wall 10F of the housing 10. At this time, the front surface of the front wall 22F is preferably flush with the front surface of the housing 10, but may protrude forward from the front surface of the housing 10 or may be recessed rearward.

The cavity 22H surrounded by the front wall 22F, the peripheral wall 22C and the rear wall 22R is filled with hydraulic oil. This hydraulic oil can flow between the inside of the shaft guide portion 24 and the cavity 22H, which will be described later, through the opening 22A formed in the central portion of the rear wall 22R.

The shaft guide portion 24 is a hollow cylindrical portion having both ends open in the axial direction, and has an inner diameter equal to the diameter of the circular opening 22A formed in the rear wall 22R of the oil storage portion 22. The shaft guide portion 24 has a function of guiding the movement of the shaft 60, which will be described later, in the front-rear direction. A groove (not shown) is formed on the inner wall of the shaft guide portion 24 at one or a plurality of points in the axial direction, and a seal ring (not shown) is fitted in the groove. This prevents hydraulic oil from leaking from the cavity 22H of the oil storage unit 22 even when the shaft 60 moves in the front-rear direction as described later.

The first contact 30, together with the second contact 40 described later, is a member constituting the contact of the electric circuit EC of the device mounted on the high-speed projectile. The first contact 30 is an annular member made of a conductive material and is supported by the carrier 32.

The carrier 32 is an annular member made of a highly heat-insulating material, and an annular groove 32G is formed on the rear surface thereof, and the first contact 30 is fitted in the groove 32G.

Further, a spring 33 is interposed between the front surface of the carrier 32 and the rear wall 22R of the oil storage portion 22 of the cylinder 20. As a result, a backward elastic force of the spring 33 acts on the carrier 32, and in the initial state, the rear surface of the carrier 32 is pressed against the intermediate inner wall 10M of the housing 10.

Further, an inner sleeve 34 made of a conductive material is tightly fitted to the outer periphery of the carrier 32, and the inner sleeve 34 and the first contact 30 are connected to each other via a conductive path W1a embedded inside the carrier 32. It is connected.

A groove 10G over the entire circumference is formed in a portion of the front inner wall 10F of the housing 10 facing the inner sleeve 34, and an outer sleeve 12 made of a conductive material is fitted in the groove 10G. The outer sleeve 12 is connected to the above-mentioned electric circuit EC via a conductive path W1b embedded in the housing 10.

The inner surface of the outer sleeve 12 is flush with the inner surface of the front inner wall 10F, and the inner sleeve 34 is formed to have an outer diameter equal to the inner diameter of the front inner wall 10F. As a result, when the carrier 32 moves in the front-rear direction as described later, the contact state between the inner sleeve 34 and the outer sleeve 12 is maintained. As a result, the first contact 30 conducts with the electric circuit EC described above via the conductive path W1a embedded inside the carrier 32, the inner sleeve 34, the outer sleeve 12, and the conductive path W1b embedded in the housing 10. Can be maintained.

The second contact 40 is provided side by side with the first contact 30 in the axial direction, and together with the first contact 30, is a member constituting a contact of an electric circuit EC of a device mounted on a high-speed projectile. The second contact 40 is an annular member made of a conductive material, and is connected to the above-mentioned electric circuit EC via a conductive path W2.

The second contact 40 is formed to have an outer diameter slightly smaller than the inner diameter of the rear inner wall 10R of the housing 10. Further, a recess 40D is formed on the outer surface of the second contact 40.

A blind hole 10H extending in the radial direction is formed in a portion of the rear inner wall 10R of the housing 10 facing the recess 40D formed on the outer surface of the second contact 40 in the initial state, and the blind hole 10H is formed. The first plunger 14 is fitted in the.

The first plunger 14 is composed of a housing 14H, a spring 14S, and a pin 14P, and a radial inward elastic force of the spring 14S acts on the pin 14P. In the initial state, the tip of the pin 14P is fitted into the recess 40D formed on the outer surface of the second contact 40. As a result, the axial movement of the second contact 40 is restricted.

However, the recess 40D is formed relatively shallowly, and the axial binding force of the pin 14P of the first plunger 14 fitted therein is relatively small. Therefore, when a large axial load acts on the second contact 40, the spring 14S of the first plunger 14 is compressed by the radial component of the load received from the inner surface of the recess 40D, and the pin 14P is recessed. It deviates from 40D. As a result, the second contact 40 can move in the axial direction.

Further, a blind hole 40H extending in the radial direction is formed on the inner surface of the second contact 40, and the second plunger 42 is fitted in the blind hole 40H.

The second plunger 42 is composed of a housing 42H, a spring 42S, and a pin 42P, and a radial inward elastic force of the spring 42S acts on the pin 42P. In the initial state, the tip of the pin 42P is in contact with the outer surface of the shaft 60, which will be described later, but the contact does not restrict the axial movement of the shaft 60.

The heat detection element 50 is an annular member made of a non-conductive material such as resin, and is fixed to the rear surface of the first contact 30 by an appropriate method. As a material constituting the heat detection element 50, as described later, a material having a melting point in the temperature range reached when the two-stage heat switch 1 receives aerodynamic heating, that is, the operating temperature range of the two-stage heat switch 1. Be selected.

The shaft 60 is a columnar member made of a non-conductive material, and the front portion thereof is fitted inside the shaft guide portion 24 of the cylinder 20. At this time, the front surface of the shaft 60 is in contact with the hydraulic oil stored in the cavity 22H of the oil storage portion 22 of the cylinder 20. In other words, the portion of the internal space of the cylinder 20 located in front of the shaft 60 is filled with the hydraulic oil, and there is no void.

The shaft 60 extends axially through the first contact 30 and the second contact 40, but an annular passage P is formed between the outer surface of the shaft 60 and the inner surface of the first contact 30. There is. Further, the inner surface of the second contact 40 is formed to have an inner diameter slightly larger than the outer diameter of the shaft 60, and a frictional force does not substantially act on the outer surface of the shaft 60. Further, on the outer surface of the shaft 60, a key groove 60G extending in the axial direction is formed in a portion having the same phase as the second plunger 42 fitted in the blind hole 40H formed on the inner surface of the second contact 40 in the circumferential direction. Is formed.

The two-stage heat switch 1 configured as described above is located at a position where the heat is efficiently transferred to the front wall 22F of the oil storage portion 22 of the cylinder 20 when the high-speed projectile receives aerodynamic heating. For example, it is placed near the head (tip) of a high-speed projectile.

As a result, the two-stage thermal switch 1 sets the electric circuit EC of the equipment mounted on the high-speed projectile at the timing when the aerodynamic heating reaches the maximum for the first time (when the high-speed projectile rises in the atmosphere from the launch point). It is not closed at the timing when the heating rate of the aerodynamic heating received is maximum (the heating rate of the aerodynamic heating received when the high-speed projectile descends in the atmosphere toward the target point) at the timing when the aerodynamic heating reaches the maximum for the second time. It operates so as to close at the timing when the maximum is reached), and the mode of the operation will be described below with reference to FIG.

2A and 2B are explanatory views showing an operating mode of the two-stage heat switch 1. FIG. 2A shows a situation at a timing when aerodynamic heating reaches a maximum at the first time, and FIG. 2B shows a situation where aerodynamic heating reaches a maximum at the first time. After that, the situation up to the timing when the aerodynamic heating becomes the maximum for the second time, (C) the initial situation at the timing when the aerodynamic heating becomes the maximum for the second time, (D) is the situation of two contacts following the situation (C). Each shows the situation of contact.

When the heat is transferred to the front wall 22F of the oil storage unit 22 of the cylinder 20 at the timing when the aerodynamic heating becomes maximum for the first time (see the arrow AH in FIG. 2A), the inside of the cavity 22H of the oil storage unit 22 The hydraulic oil stored in the cylinder is also heated and expands. As a result, an axially backward load acts on the front surface of the shaft 60, and the shaft 60 moves rearward (see the white arrow in the figure).

At this time, the first contact 30 supported by the carrier 32 having a distance (passage P) from the shaft 60 and the second contact 40 whose axial movement is restricted by the first plunger 14 are in the initial state. The same state is maintained, but the pin 42P of the second plunger 42 of the second contact 40 is in a state of being fitted into the keyway 60G of the shaft 60.

When the timing when the aerodynamic heating reaches the maximum for the first time has passed, the front wall 22F of the oil storage portion 22 of the cylinder 20 dissipates heat (see the arrow HD in FIG. 2B), and the cavity 22H of the oil storage portion 22 is accompanied by this. The hydraulic oil stored inside shrinks. As a result, an axially forward load acts on the shaft 60, and the shaft 60 moves forward (see the white arrow in the figure).

At this time, the pin 42P of the second plunger 42 fitted in the key groove 60G of the shaft 60 receives an axially forward load from the rear end surface of the key groove 60G. As described above, since this load is large due to the decrease in the volume of the hydraulic oil, the second contact 40 overcomes the axial binding force of the pin 14P of the first plunger 14 and moves forward. .. As a result, the front surface of the second contact 40 comes into contact with the rear surface of the heat detection element 50, and further moves the first contact 30 and the carrier 32 forward together with the heat detection element 50 against the elastic force of the spring 33. At the same time, the pin 14P of the first plunger 14 is in a state of being depressed inward in the radial direction behind the second contact 40. As a result, the second contact 40 is in a state in which the movement of the second contact 40 in the axial rearward direction is restricted by the pin 14P of the first plunger 14.

Subsequently, when the heat is transferred to the front wall 22F of the oil storage portion 22 of the cylinder 20 at the timing when the aerodynamic heating becomes maximum for the second time (see the arrow AH1 in FIG. 2C), the aerodynamic heating is 1 Similar to the timing when the maximum is reached, the hydraulic oil stored in the cavity 22H of the oil storage unit 22 is also heated and expanded, and as a result, the shaft 60 moves rearward (see the white arrow in the figure).

However, since the axial length of the key groove 60G of the shaft 60 is larger than the amount of movement of the shaft 60 to the rear at this time, the second key groove 60G is fitted into the key groove 60G. The pin 42P of the second plunger 42 of the contact 40 does not come into contact with the front surface of the keyway 60G and receive an axially backward load. Further, the movement of the second contact 40 backward in the axial direction is restricted by the pin 14P of the first plunger 14. Therefore, at the timing when the aerodynamic heating reaches the maximum for the second time, the axial position of the second contact 40 does not change.

On the other hand, as shown by the arrow AH2 in FIG. 2C, the above-mentioned heat further causes the peripheral wall 22C, the rear wall 22R, the shaft 60, and the second contact 40 from the front wall 22F of the oil storage portion 22 of the cylinder 20. It is transmitted to the heat detection element 50 via the heat detection element 50. As described above, since the shaft 60 and the second contact 40 are members having a function of transferring heat to the heat detection element 50, it is preferable that the shaft 60 and the second contact 40 are made of a material having high thermal conductivity (for example, copper or the like).

When the heat transfer to the heat detection element 50 continues in this way, the heat detection element 50 finally begins to melt. At this time, a part of the melted liquid heat detection element 50 goes to the space S formed between the rear surface of the carrier 32 and the intermediate inner wall 10M of the housing 10, and the rest goes through the passage P to the space in front of the carrier 32 (spring). It flows out to the space where 33 is housed). Then, when the axial thickness of the heat detection element 50 decreases as the melting progresses, the carrier 32 supporting the first contact 30 gradually moves backward in the axial direction due to the backward elastic force of the spring 33.

Finally, when all the heat detection elements 50 are melted and flow out into the space in front of the carrier 32, the rear surface of the first contact 30 and the front surface of the second contact 40 come into contact with each other as shown in FIG. 2 (D). The electric circuit EC will be closed.

As described above, the length of the cylinder 20 and the shaft 60 increases due to the inflow of heat to the front end (front wall 22F of the oil storage unit 22), and the length decreases due to the outflow of heat from the front end. In addition to acting as a unit, it also has the function of transferring the heat flowing in from the front end to the second contact 40.

Further, the first plunger 14, the second plunger 42, and the key groove 60G formed on the shaft 60 position the second contact 40 in the initial state when the expansion / contraction unit is expanded / contracted (first time). That is, the position is changed from the position where there is a gap between the first contact 30 and the heat detection element 50 fixed to the surface of the first contact 30 to the position where the heat detection element 50 comes into contact with the heat detection element 50. Acts as a unit.

As a result, when the expansion / contraction unit expands / contracts due to the first heating (corresponding to the timing when the aerodynamic heating reaches the maximum at the first time) and the subsequent heat dissipation, the second contact 40 moves due to the action of the position change unit and the heat detection element 50. The heat detection element 50 is heated by the heat transferred through the expansion / contraction unit and the second contact 40 by the second heating (corresponding to the timing when the aerodynamic heating becomes the maximum for the second time). When it melts and runs off, the first contact 30 pressed toward the second contact 40 by the spring 33 finally contacts the second contact 40, and the electric circuit is closed.

As described above, according to the two-stage thermal switch 1 of the present invention, the aerodynamic heating is 2 for the electric circuit EC of the device mounted on the high-speed projectile such that the aerodynamic heating is maximized twice during the mission. When it is required to close at the timing when the aerodynamic heating becomes the maximum at the first time, the electric circuit EC is not closed at the timing when the aerodynamic heating becomes the maximum at the first time, and the electric circuit is surely performed at the timing when the aerodynamic heating becomes the maximum at the second time. The excellent effect of being able to close the EC can be obtained.

The heat detection element 50 may be formed so as to have a size such that it is completely melted by the amount of heat input when the aerodynamic heating reaches the maximum for the second time, and the shape thereof is annular as described above. It does not have to be. For example, a plurality of heat detection elements formed as a prismatic or columnar block may be fixed at locations separated from each other in the circumferential direction on the rear surface of the first contact 30.

1 Two-stage thermal switch 10 Housing 14 First plunger (position change unit)
14P pin 20 cylinder (expansion / contraction unit)
30 1st contact 32 Carrier 33 Spring 40 2nd contact 42 2nd plunger (position change unit)
42P pin 50 Heat detection element 60 Shaft (expansion / contraction unit)
60G keyway (position change unit)

Claims (4)

The first contact and the second contact, which cooperate to form the contacts of the electric circuit,
A heat detection element fixed to a surface of the first contact facing the second contact and having a melting point in the operating temperature region is provided.
In the initial state, the second contact and the heat detecting element are arranged so that there is a gap between them.
After the first inflow of heat, the second contact and the heat detection element come into contact with each other.
A two-stage heat characterized in that the first contact and the second contact come into contact with each other and the electric circuit is closed due to the heat detection element melting and flowing out at the time of the second inflow of heat. switch. Hollow cylindrical housing and
A telescopic unit housed in the housing, the axial length increases due to the inflow of heat to the front end, and the axial length decreases due to the outflow of heat from the front end.
Further comprising a position changing unit for changing the axial position of the second contact in the housing.
The first contact and the second contact are housed axially side by side in the housing, and the first contact is supported by a carrier housed axially movably in the housing.
The carrier is pressed in a direction toward the second contact by a spring, and is initially arranged at a position where there is a gap between the heat detection element and the second contact.
When heat flows into the front end of the telescopic unit to increase the length of the telescopic unit and then heat flows out from the front end to decrease the length of the telescopic unit, the position change unit causes the second. The two-stage thermal switch according to claim 1, wherein the axial position of the contact in the housing is changed from the position in the initial state to the position in contact with the heat detection element. The telescopic unit is
A hollow cylindrical cylinder fixed in the housing,
It comprises a cylindrical shaft made of a non-conductive material, the front end of which is axially movable and inserted into the cylinder.
The hydraulic oil is stored in the cylinder, and the front end of the shaft is in contact with the hydraulic oil.
With the inflow of heat to the front end of the cylinder, the hydraulic oil expands and the shaft is displaced rearward, so that the length of the telescopic unit increases.
2. The two-stage thermal switch described. The position change unit is
A first plunger mounted so that the pin can project radially inward from the inner surface of the housing and configured to restrict the axial movement of the second contact in the initial state.
A second plunger attached so that the pin can protrude radially inward from the inner surface of the second contact,
It is composed of a key groove provided on the outer surface of the shaft at a position in the same phase as the second plunger in the circumferential direction and extending in the axial direction.
The tip of the pin of the second plunger is in contact with the outer surface of the shaft in the initial state.
As the length of the telescopic unit increases, the tip of the pin of the second plunger fits into the keyway.
After that, when the length of the telescopic unit decreases, the tip of the pin of the second plunger engages with the rear end surface of the key groove, so that the axial position of the second contact is changed, and at the same time, the said. The claim is characterized in that the axial movement of the second contact is restricted by the tip of the pin of the first plunger falling inward in the radial direction behind the second contact. The two-stage thermal switch according to 3.

Images