JPS5952399B2 - bimetal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bimetal that exhibits rapid displacement at a set temperature.

Bimetals, which have been widely used in the past, exhibit curvature displacement that is proportional to temperature changes at an approximately constant rate.

Therefore, in applications that require rapid displacement at a set temperature, for example, when bimetal is used directly in a contact drive mechanism, a so-called quick-acting mechanism is required.

For example, the slow curved displacement of the bimetal itself is made into a rapid displacement by using a repulsion plate, in combination with a spring, or by using a magnet.

This interlocking bimetal mechanism is widely used, but
Providing an interlocking mechanism necessitates an increase in the size of the device and a complicated design, which is undesirable.

From this point of view, bimetals that exhibit rapid displacement at a certain temperature have recently been developed.

This bimetal uses an alloy that has a shape memory effect on the high expansion side, and a typical alloy is Ti (
titanium)-nickel (Ni) alloy, and Au
(gold)-Cd (cadmium) alloy, Cu (copper)-Al(
aluminum) alloy, Cu-Al-Ni alloy, Cu-A
l-Mn (manganese) alloy%'Cu-Al-Pd (paratium) alloy, Cu-Zn (zinc) alloy, Cu-
Examples include Zn-Au alloy.

A bimetal whose high expansion side is made of such an alloy can obtain rapid displacement due to the shape memory effect at a predetermined temperature without using an interlocking mechanism.

However, the alloy with the shape memory effect described above is T
Except for the i-Ni alloy, all of them have extremely difficult workability, especially cold working, and it is difficult to obtain a bimetal with a desired shape.

In addition, 'l' 1-Ni alloys are relatively easy to cold work, but the temperature range in which sudden and severe displacement occurs is at most 60~70°C.
The problem was that it was not possible to obtain rapid displacement in a higher temperature range.

Furthermore, the bimetal using the alloy having the shape memory effect described above did not have sufficient reversibility for repeated operations.

An object of the present invention is to provide a bimetal that exhibits rapid displacement in a desired temperature range, has excellent workability, and has sufficient removability.

That is, the bimetal of the present invention is composed of an alloy consisting of 15 to 30% manganese by weight and the remainder substantially iron on the high expansion side, and a temperature near the temperature at which the coefficient of thermal expansion of the alloy rapidly increases on the low expansion side. has a coefficient of thermal expansion that is substantially constant at
In addition, it is characterized in that it is made of an alloy whose thermal expansion coefficient is smaller than the increased thermal expansion coefficient of the alloy.

In the alloy constituting the high expansion side of the bimetal of the present invention, manganese is necessary to increase thermal expansion, and the amount is 15
If it is less than 30%, the effect will not be sufficient, and if it exceeds 30%, it will not exhibit rapid thermal expansion, so it was set within this range.

This alloy has good workability and exhibits a rapid increase in thermal expansion coefficient in a relatively high temperature range.

The alloy constituting the low expansion side of the bimetal of the present invention has a coefficient of thermal expansion that is substantially constant near the temperature at which the coefficient of thermal expansion of the alloy constituting the high expansion side increases rapidly, and If it is smaller than the increased coefficient of thermal expansion of the alloy constituting the high expansion side, it can be a bimetal that exhibits rapid displacement at a predetermined temperature.

In order to effectively use the characteristics of the bimetal of the present invention, which exhibits rapid displacement at a predetermined temperature, in contact drive mechanisms, etc., it is necessary to maintain a low expansion temperature up to the temperature at which the alloy constituting the high expansion side rapidly expands. The coefficient of thermal expansion of the alloy constituting the side is often approximately the same as that of the alloy constituting the high expansion side, and in this case, for example, 5US304.
Austenitic stainless steel such as 5US310 can be used.

Carbon (C) is mixed into each alloy as an impurity.
, sulfur (S), phosphorus (P), and other impurities, and aluminum (Al) and silicon (added as deoxidizing agents during melting).
It is desirable that Si) etc. be 1% or less.

Examples of the present invention will be described below along with comparative examples.

Samples were prepared by melting alloys having the compositions shown in Table 1 using a high-frequency induction melting furnace.

Next, the temperature at which the thermal expansion suddenly changes for the alloys of Samples 1 to 5 was determined, and the results are shown in Table 1 together with the composition ratio.

As is clear from Table 1, samples 2 to 4, which are alloys constituting the high expansion bimetal of the present invention, have a sharp turning point in thermal expansion.

Next, with the combination of alloys shown in Table 2, the high expansion alloy and the low expansion alloy are bonded by hot rolling so that the plate thickness is 1:1, and then conventional processes such as cold rolling and annealing are performed. l'm by means
A bimetal with a thickness of m was obtained, and test pieces were prepared for each.

In this case, the workability of the bimetal of the present invention was extremely good.

Table 2 shows the commonly used bimetals (
JIS-TM-1 equivalent) is also shown.

The bending properties of these specimens were compared, and the longitudinal elastic modulus was also investigated.

Curvature characteristics were measured by measuring the displacement of the free end of a cantilever type with an effective length of 100 mm, and the results are shown in the figure.

The arrows in the figure indicate the direction of displacement due to heating and cooling.

The longitudinal elastic modulus is also shown in Table 2.

As is clear from the figure, the displacement of sample 14 for comparison increases almost linearly with temperature changes, whereas the displacement of the bimetal of the present invention increases rapidly at the solution temperature. There is.

Furthermore, the temperature at which the displacement changes rapidly can be easily set to a desired temperature by adjusting the amount of manganese, and the temperature range is wide.

Furthermore, as is clear from the figure, since the bimetal of the present invention exhibits hysteresis in its bending characteristics, it also has the advantageous effect that a reset mechanism is not particularly required when used as a protection element.

Furthermore, since the bimetal of the present invention has an extremely large amount of displacement per unit temperature, it can be used in mechanisms that require high sensitivity.

In addition, according to Table 2, the bimetal of the present invention has a large longitudinal elastic modulus, so it is possible to take a large operating stress.

Furthermore, when the bimetal of the present invention was operated repeatedly, the reversibility was sufficiently satisfactory.

The bimetal of the present invention in the above-mentioned embodiments is a combination in which there is almost no displacement up to the temperature at which the alloy constituting the high expansion side rapidly expands, but the alloy constituting the low expansion side is By selection, it is possible to create a bimetal that is bent in the opposite direction up to the temperature at which the alloy constituting the high expansion side rapidly expands, and then reversed around the above temperature.
Even in this case, the effects of the embodiments described above can be applied as they are.

As described above, the bimetal of the present invention exhibits rapid displacement at a predetermined set temperature, and even when used directly in a contact drive mechanism, it produces favorable results without causing any welding phenomenon.

Furthermore, the bimetal of the present invention has excellent workability and can be easily processed into a desired shape.

Furthermore, the rapid displacement of the bimetal of the present invention allows it to be used in a high temperature range.

Furthermore, the bimetal of the present invention is made of inexpensive materials, and therefore can be used extremely economically for safety devices such as circuit breakers for home appliances and thermal protectors for various industrial equipment.

Note that it is within the scope of the present invention to use an alloy plate of nickel, copper, or the like as an intermediate layer or surface layer as a laminated plate in order to improve characteristics such as reducing electrical resistance.

[Brief explanation of the drawing]

The figure is a diagram showing the curvature characteristics of a bimetal according to the present invention and a bimetal of a comparative example.

Claims (1)

[Claims] 1. The high expansion side is composed of an alloy consisting of 15 to 30% manganese by weight and the remainder is substantially iron, and the low expansion side is the temperature at which the coefficient of thermal expansion of the alloy rapidly increases. 1. A bimetal comprising an alloy having a coefficient of thermal expansion which is substantially constant in the vicinity, and which coefficient of thermal expansion is smaller than an increased coefficient of thermal expansion of said alloy. 2. A patent claim in which the alloy constituting the low expansion side has a coefficient of thermal expansion substantially equivalent to that of the alloy constituting the high expansion side up to a temperature near which the coefficient of thermal expansion of the alloy constituting the high expansion side increases rapidly. The bimetal described in item 1. 3. The bimetal according to any one of claims 1 to 2, wherein the alloy constituting the low expansion side is austenitic stainless steel.