JPS63212816A - Indicating instrument using bimetal - Google Patents

Abstract

PURPOSE:To improve the precision in the indication of a indicator using bimetal and to make it small in size, by providing a U-shaped elastic plate in the track of displacement of a bimetal and by making the bimetal engage with a free end of the U-shaped elastic plate in the course of displacement of the bimetal. CONSTITUTION:When a current of a heat wire 5 increases with a rise in the temperature of water, a bimetal 4 is displaced to a temperature whereat it engages with a U-shaped elastic plate 11. It receives a load from the U-shaped elastic plate 11 and stops at a point of engagement position until it reaches a temperature whereat it has the same force of displacement with said load. Thereafter the bimetal 4 can continue further to be displaced, since the force of displacement thereof becomes larger than the load of the U-shaped elastic plate 11. Accordingly, a drive pin 8 acts on guide hole 6a in accordance with the characteristic of displacement of the bimetal 4, so as to make a pointer indicate each temperature. By this constitution, the characteristic of displacement of the bimetal is turned to be nonlinear, so as to improve the precision in indication and to make the bimetal small in size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is directed to a bimetallic indicating instrument used as a water temperature gauge, oil temperature gauge, oil pressure gauge, etc. mounted on an automobile.

[Prior Art] A bimetallic indicator drives a pointer by displacement of a bimetal, and has a linear deflection angle characteristic as shown in FIG.

However, in recent years, with the diversification of indicating functions, linear characteristics are no longer necessary.For example, in the case of a water temperature gauge, it is necessary to indicate a temperature sufficient to heat the vehicle interior at low temperatures, and accurately set a temperature to prevent overheating at high temperatures. It is important to give an indication, but at intermediate temperatures, the range of changes in cooling water temperature has become larger as the output of the engine has increased, so the range of changes in the indicator's indication has become larger. Therefore, there has been a need for a water temperature meter that eliminates this extra variation and indicates the optimum temperature of the engine, that is, an indicator having nonlinear characteristics as shown in FIG. 9. As a meter having this characteristic, Japanese Utility Model Application Publication No. 115326/1983 has been proposed in which the guide shape of the pointer is made non-linear in order to improve the structure of the joint between the bimetal and the pointer.

[Problem to be solved by the invention 1 However, with this meter, (1) the shape of the guide hole of the pointer must be changed according to the required characteristics, and (2) the width of the indication is limited, so there is a large constant area. It is difficult to set up (3
) Since a large amount of play is required for the drive pin to move smoothly within the guide hole, there are problems such as difficulty in obtaining good indication accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bimetallic indicating instrument that has a function that responds to the diversification of indicating functions, is small in size, and has high indicating accuracy.

[Means for Solving the Problem] The present invention provides a bimetallic indicating instrument in which a pointer is driven according to the amount of displacement of a bimetal, in which a U-shaped elastic plate is installed in the displacement locus of the bimetal, and the U-shaped elastic plate One end serves as a fixed fulcrum, and the other end is provided with a stopper that applies an initial load to and locks the U-shaped elastic plate itself, and the bimetal engages with the other end of the U-shaped elastic plate during the displacement process. This makes the displacement characteristics of the bimetal nonlinear.

[Operation] First, the principle of the present invention will be explained. As shown in Fig. 5, the bimetal M curves according to the ambient temperature, and the desired amount of displacement δ can be obtained at its free end. δ increases, but if a load W is applied to the bimetal M in advance,
The bimetal M does not displace at all until the displacement force becomes equal to the load W, and when the ambient temperature T rises from To to T1 and the displacement force becomes larger than the load W, the bimetal M has the characteristics as shown by the chain line in Fig. 6. Displace. Therefore, for example, if the load W is set to be applied at the position of the displacement amount δ in FIG. M has the displacement characteristics shown in FIG.

According to the above principle, the bimetal is uniformly displaced until its tip engages with the U-shaped elastic plate, and once it engages with the U-shaped elastic plate, it temporarily stops at the engagement position. Thereafter, when the displacement force of the bimetal becomes larger than the initial load applied to the U-shaped elastic plate, the bimetal is displaced together with the U-shaped elastic plate. Therefore, the displacement characteristic of the bimetal becomes nonlinear as shown in FIG. 7, and the pointer also exhibits a nonlinear deflection angle characteristic as shown in FIG.

[Effects of the Invention] As described above, the present invention makes it possible to obtain an indicating instrument with nonlinear characteristics by engaging a U-shaped elastic plate with a bimetal. Moreover, by changing the engagement position between the U-shaped elastic plate and the bimetal, the position at which nonlinear displacement starts can be easily changed, and by changing the initial load applied to the U-shaped elastic plate, the bimetal's constant area can be easily changed. can be set in various ways.

Furthermore, since it is a U-shaped elastic plate, the length between the fixed fulcrum of the U-shaped elastic plate and the engagement point with the bimetal is substantially large, and the load change after engagement with the bimetal can be reduced. Therefore, although it is small, various indicating characteristics can be set, and a bimetallic indicating instrument with a good indication of 117 degrees can be obtained.

[Example] Next, the present invention will be described with reference to FIGS. 1 and 2 regarding an example of a water temperature gauge for an automobile.

FIG. 1 shows the water temperature gauge with the scale plate 1 removed. Two conductive screws 3 pass through the main body 2 made of insulating resin to the back surface for attachment to an instrument panel of an automobile. A heat wire 5, which is a nichrome wire coated with a highly heat-resistant insulating coating, is wound around the bimetal 4, and both ends of the heat wire 5 are fixed to two screws 3 with conductive treatment. .

The pointer 6 is rotatable about a shaft 7, and has a linear guide hole 6a.
A drive pin 8 attached to the free end of the bimetal 4 moves to drive the pointer 6.

The bimetal 4 is attached to the support base 9 with a bimetal attachment part 9a, and the maximum deflection angle of the pointer 6 is set at a set point (1 (
), it can be rotated together with the support base 9 using the rotation fulcrum 9b as the fulcrum. This rotation fulcrum 9
b is rotatably supported by the base 10. The base 10 is rotatably supported by the main body 2 at a base fulcrum 10a so that the pointer 6 can be adjusted to the initial position setting point.

A U-shaped elastic plate 11 is provided along the displacement locus of the bimetal 4. One end of this U-shaped elastic plate 11 is connected to the frame 1
An elastic plate attachment formed by bending from 2 is fixed to the portion 12a. In addition, the other end is bent into a step shape toward the bimetal 4 side at a position where it does not contact the heat wire 5, and the crotch portion 11
The crotch portion 11a is provided with a bimetal receiver portion 11b, which engages with the bimetal 4, by stamping.

The U-shaped elastic plate 11 is further bent from the crotch portion 11a to the side opposite to the bimetal, and is locked by a stopper 12b formed by bending from the frame 12. This stopper 12b applies an initial load to the U-shaped elastic plate 11.

The frame 12 is attached to the support base 9 on which the bimetal 4 is attached, with nl:4, which adjusts the distance between the U-shaped elastic plate 11 and the bimetal 4 while applying the initial JIJI load to the U-shaped elastic plate 11. The attachment is done at the portion 12c. Therefore, the frame body 12 is provided with a narrow bridging portion 12d relative to the frame body J-attached portion 12c so that it can be rotated by using this portion as a fulcrum.

Therefore, the frame body 12 is entirely supported by the support base 9 and further by the base 1.
Since it can rotate with 0, not only does it not affect the initial position setting and maximum deflection angle setting of the pointer 6, but also the frame body can be attached to the frame by plastically deforming the bridging part 12d.
Since the elastic plate mounting can displace the position of the portion 12a and the stopper 12b with respect to the 2C1 support stand 9 and the base 10, the U-shaped elastic plate 11 can be attached without changing the initial load of the U-shaped elastic plate 11. The engagement position between the bimetal 4 and the bimetal 4 can be adjusted. Further, when attaching the elastic plate, the initial load of the U-shaped elastic plate 11 can be changed by changing the relative position or angle between the part 12a and the stopper 12b. The initial weight of the U-shaped elastic plate 11 can also be changed by plastically deforming it.

By installing the above U-shaped elastic plate 11, the water temperature gauge operates as follows.

When the current flowing through the wires 1 to 5 increases as the water temperature t rises, the bimetal 4 begins to displace as per the conventional characteristics. When the bimetal 4 is displaced to a temperature t2 at which it engages with the U-shaped elastic plate 11 as shown in FIG. 3, it receives a load from the U-shaped elastic plate 11, and until it reaches a temperature t3 at which the displacement force is equal to this load, Stops at the engagement position. After that, the displacement force of the bimetal 4 becomes larger than the load of the U-shaped elastic plate 11, so that the displacement can be continued as shown in FIG. 4. As a result, the bimetal 4 is displaced with the characteristics shown in FIG. Therefore, depending on the displacement characteristics of this bimetal 4, the drive pin 8 acts on the guide hole 6a, and the pointer 6
to display each temperature. Therefore, the pointer 6 shows a deflection angle as shown in FIG.

This U-shaped elastic plate 11 is stepped only near the engagement point in order to prevent unnecessary approach and contact with the two heat wires 5 and the bimetal 4, so that the influence on the thermal characteristics of the bimetal 4 can be suppressed. Can be done.

In addition, by forming the U-shaped elastic plate 11 into a U-shape, the actual distance between the fixing point of the U-shaped elastic plate 11 and the engagement point with the bimetal 4 can be increased, so that after engagement with the bimetal 4 Load changes can be reduced, and the indicating instrument can be made very compact.

As described above, although the present invention is small, it is possible to obtain various nonlinear characteristics with high precision.

FIG. 10 shows a second embodiment, in which the shape of the frame 12 of the engagement position adjustment mechanism is changed.

In the figure, the same reference numerals as in FIG. 1 indicate the same parts.

Here, the frame 12 is rotatably supported by the support stand 9 at the frame mounting part 12e, and by rotating this part as a fulcrum, the U-shaped elastic plate 11 and the bimetal 4 are engaged. It has a structure that adjusts the alignment position.

It is also possible to adjust the engagement position at which nonlinear displacement starts using methods other than the above embodiments.

Each of the above embodiments is an example of application as a water temperature gauge, but it can be applied to various bimetal type indicating instruments as long as the indicator is driven according to the displacement of the bimetal.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of a bimetallic indicating instrument according to the present invention, FIG. 2 is a plan view of the bimetallic indicating instrument according to the present invention, and FIGS. 3 and 4 are: The schematic diagrams of the main parts of the bimetal type indicating instrument according to the present invention, and Figures 5 to 9 are diagrams used to explain the principle of the present invention, and Figure 5 is a general displacement diagram of the bimetal. , FIGS. 6 and 7 are bimetal displacement characteristic diagrams, FIGS. 8 and 9 are pointer deflection negative characteristic diagrams, and FIG. 10 is a perspective view of a second embodiment of the meter of the present invention.

Claims (1)

[Scope of Claims] 1) In a bimetal indicating instrument in which a pointer is driven according to the amount of displacement of a bimetal, a U-shaped elastic plate is installed in the displacement locus of the bimetal, and one end of the U-shaped elastic plate is set as a fixed fulcrum. and a stopper that locks the other end of the U-shaped elastic plate by applying an initial load to the U-shaped elastic plate itself, and the bimetal engages with the other end of the U-shaped elastic plate during the displacement process. Expression indicating instrument. 2) The stopper is provided on the same frame as the frame that fixes the U-shaped elastic plate, and adjusts the distance between the U-shaped elastic plate and the bimetal while applying an initial load to the U-shaped elastic plate. The bimetallic indicating instrument according to claim 1, characterized in that it is provided with a mechanism.