JPS61250915A - Pressure sensitive switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a pressure-sensitive switch that detects an intentional or unexpected contact between an object or a person and issues an output signal.
Related to switches that are used in various industrial applications, automotive peripheral applications, crime prevention, emergency applications, sports and daily life peripheral applications, etc., and exhibit excellent responsiveness and durability, as well as sufficient waterproof and dustproof properties. It is something.

(Prior Art) Conventionally known switches of this type include, for example, a microswitch that detects displacement of an automobile brake pedal in the depression direction and turns on a brake lamp, and a microswitch that is used in connection with the operation of a clutch pedal of construction machinery. There are microswitches that switch hydraulic circuits.

However, such microswitches have problems such as increased size of the switch due to having movable contacts and corrosion of the contacts, as well as low reliability against dust/water resistance, vibration resistance, and overload. Ta.

Therefore, a switch structure consisting of a pressurized conductive rubber, a pair of flexible electrodes placed apart from the pressurized conductive rubber, and an insulating outer skin covering these electrodes is used in the pedal body of brake pedals, clutch pedals, etc. At the same time, the switch structure and pedal body are completely covered with pedal rubber without any gaps, and a lead wire is connected to the switch structure to form a pressure-sensitive switch. When pressure is applied, the pressure-sensitive switch generates an electrical signal, and based on this signal, the brake light is turned on, the hydraulic circuit is switched, etc., which solves the problems of microswitches and other devices. being done.

Note that this switch structure is made of plain braided wire, wire mesh, Tokyo Dodo wire, conductive elastomer film, etc., sandwiching pressurized conductive rubber, for example, based on silicone rubber, mixed with metal powder or other conductive particles. The switch structure can be constructed by arranging flexible electrodes and covering them with an insulating jacket, also made of silicone rubber, for example, so that the switch structure can be When the external force exceeds a predetermined value, the electrical resistance value of the pressurized conductive rubber rapidly decreases to allow electrical conduction between one electrode and the other electrode.

(Problem to be Solved by the Invention) However, in this proposed technology, in order to ensure that the pressure-sensitive switch always operates appropriately regardless of the load acting on any part of the pedal, it is necessary to In this case, it is necessary to arrange the switch structure very closely without any gaps, and even in every corner, but the cost of the switch structure itself is quite high, so the price of the pressure-sensitive switch is also quite high. This problem arises in pressure-sensitive switch applications that require a larger surface area than brake pedals, clutch pedals, etc.
For example, this was particularly important for wiping automatic door multi-layer mats, swimming pool touch panels, etc.

The present invention advantageously solves these problems, and provides an inexpensive pressure-sensitive switch that can sensitively respond to loads acting on any part, even when the arrangement density of the switch structure is reduced. It provides:

(Means for Solving the Problems) In particular, the pressure-sensitive switch of the present invention has an elastic outer cover disposed at a predetermined interval on one side of a soft or hard base plate, and at least a peripheral portion of the elastic outer cover. is fixed to the base plate, and a string-like switch structure, which can be constructed in the same manner as described above, is arranged between the base plate and the elastic outer skin at a low density. The outer skin and
A space is defined by the switch structure, and a lead wire is connected to the switch structure.

(Function) In this pressure-sensitive switch, when an external force of a predetermined value or more acts on a portion of the elastic outer cover corresponding to the switch structure in a direction intersecting the pressurized conductive rubber surface of the switch structure,
The external force is transmitted directly to the pressurized conductive rubber via the elastic jacket, the insulating jacket and the flexible electrode, so that the conduction of both flexible electrodes and thus the actuation of the switch is brought about with good sensitivity.

On the other hand, when an external force acts on a portion of the elastic skin corresponding to the space defined by the base plate, the elastic skin, and the switch structure, the volume of the space is reduced and the elastic skin is Due to the large deformation, an external force acts on the switch structure adjacent to the space in the compression direction, in other words, in a direction crossing the pressurized conductive rubber surface, which also makes the switch structure sensitive to external forces. in response to conduction of both flexible electrodes.

Therefore, according to this pressure-sensitive switch, even if the arrangement density of the switch structure is reduced, it can still respond sensitively to loads acting on any part of the switch structure, especially because of the existence of the space. The pressure-sensitive switch itself can be made inexpensive.

Note that if the space defined by the base plate, the elastic outer skin, and the switch structure has a volume-changeable material, such as a foam material, disposed therein, the volume of the foam material may change. By appropriately selecting the bulk modulus, the response sensitivity of the pressure-sensitive switch can be adjusted as required.

Furthermore, if the elastic skin is brought into close contact with the base plate at least in its peripheral area, the pressure-sensitive switch It provides its own superior air- and liquid-tightness, and in addition allows sensitivity adjustment of the switch based on changes in air or other volume enclosed within the enclosed space.

(Example) The present invention will be explained below based on illustrated examples.

FIG. 1 is a diagram showing an embodiment of the present invention, and 1 in the figure is
The entire brake pedal is shown.

This brake pedal 1 includes a swing lever 2, a hard pedal body portion 3 as an example of a base plate fixed to one end of the swing lever 2, and a surface of the pedal body portion 3 that corresponds to the swing lever 2. , and a pedal rubber 4 as an example of an elastic outer skin which is covered at a predetermined interval from the pedal rubber 4, and the peripheral portion of the pedal rubber 4 in this example is fitted onto the pedal body portion 3, and is bonded, screwed, etc. It is fixed there by.

Here, if the peripheral part of the pedal rubber 4 is brought into close contact with the pedal body part 3 by vulcanization or other means, the space surrounded by the pedal body part 3 and the pedal rubber 4 will be completely airtight and liquid-tight. It will be.

Further, here, as shown in FIG. 1(b), an integrated string-like switch, which will be described in detail later, is installed between the pedal body part 3 and the pedal rubber 4, along the periphery of the space surrounded by them. By arranging the structure 5, the pedal body portion 3, the pedal rubber 4, and the switch structure 5 define a space portion 6 whose volume can be changed. If the switch structure 5 is disposed in close contact with the pedal body portion 3 and the medal rubber 4, the switch structure 5 and the pressure-sensitive switch 7 themselves can have excellent responsiveness. Of course, the switch assembly 5 may be separated from at least one of the pedal body portion 3 and the pedal rubber 4 as long as the switch assembly 5 can be reliably maintained in a predetermined position.

FIG. 2 is an enlarged sectional view illustrating the switch structure;
This switch structure 5 has a pair of flexible electrodes 9, 9 arranged with a pressurized conductive rubber 8 in between, and the flexible electrodes 9, 9 and the pressurized conductive rubber 8 preferably have water resistance and heat resistance. This switch structure 5 and its flexible electrodes 9, 9 are covered with an insulating outer skin 10 having
In the initial position, for example in the end position, the lead wire 11.1
Connect 1 to each.

In the illustrated example, each flexible electrode 9.9 is arranged at a distance from the surface of the pressurized conductive rubber 8, but these can be arranged on the condition that short-circuiting of the electrodes 9.9 is reliably prevented. It is also possible to arrange it in contact with the surface of the pressurized conductive rubber 8.

In the pressure-sensitive switch 7 configured as described above, the position where the pedal force applied to the pedal rubber 4 of the brake pedal 1 is applied corresponds to the embedded position of the switch structure 5, as shown by arrow A in FIG. 19(a). position, the pedal 1 is swung by the pedal force and a master cylinder (not shown) is actuated, and an external force corresponding to the magnitude of the pedal force is directly transmitted from the pedal rubber 4 to the switch structure 5. When the external force is larger than a predetermined value, the insulating outer cover 10 and the flexible electrode 9 of the switch assembly 5
, 9, the pressurized conductive rubber 8 is pressurized to a state where its resistance value is significantly reduced, and thus the conduction between the flexible electrodes 9, 9 and the lead wires 11, 11 is also maintained. As a result, the brake light will be turned on.

On the other hand, if the position where the external force acts on the pedal rubber 4 is a position corresponding to the space part 6, as shown by arrow B in FIG. , the pedal rubber 4 is largely elastically deformed as shown by the imaginary line in the figure, and the part of the rubber 4 corresponding to the switch structure 5 receives a tensile force in the direction along the deformed pedal rubber 4, as shown by the arrow in the figure. acts, so that a tensile force acts, and the tensile force produces a component force in a direction intersecting the surface of the pressurized conductive rubber 8, in the illustrated example, a direction orthogonal to the surface of the pressurized conductive rubber 8. Therefore, when this force component is greater than a predetermined value, the brake lamp is turned on in the same manner as described above.

It should be noted here that the pressure on the pedal rubber 4 required to turn on the brake lamp increases as the position of action approaches the center of the pedal rubber 4, but since the difference in the required depression force is small, this pressure-sensitive switch 7 can operate almost equally no matter where the pedal force is applied.

In such a depressed state of the brake pedal 1, after the required work by the vehicle's braking device is completed, by removing the pedal force applied to the pedal rubber 4, the external force acting on the switch structure 5 is also removed. As a result, the pressurized conductive rubber 8 once again has a high electrical resistance value, and the conduction between the two flexible electrodes 9 is interrupted. Therefore, in this case, the brake lamp is turned off.

Here, the elastic return of the pedal rubber 4 when a pedal force is applied to a position corresponding to the space 6 of the pedal rubber 4 is ensured, for example, by the re-inflow of air that has flowed out from the space 6. Become.

Therefore, even if the arrangement density of the switch structure 5 is reduced, it is possible to provide an inexpensive pressure-sensitive switch 7 that can sensitively respond to loads acting on any part. 7 can exhibit sufficient dustproof and waterproof properties, especially under the airtightness and liquidtightness inherent to the insulating outer cover 10 of the switch assembly 5. Here, if the peripheral part of the pedal rubber 4 is brought into close contact with the pedal body part 3, the pressure-sensitive switch 7 can be completely airtight and liquid-tight even when the insulating outer cover 10 is not air-tight or liquid-tight. It can bring sex.

Moreover, since the switch structure 5° here does not have a flexible contact, the switch 7 can be made sufficiently small, the problem of contact corrosion can be advantageously eliminated, and furthermore, it has sufficient resistance. It can have vibratory properties.

In addition, when an external force is applied to the switch assembly 5, the switch assembly 5 undergoes elastic deformation in an amount corresponding to the magnitude of the external force mainly under the action of the pressurized conductive rubber 8 and the insulating outer cover 10. There is no risk of damage to the pressure sensitive switch 7 due to overload.

The present invention has been described above based on the illustrated example. Here, in order to adjust the operating load of the pressure-sensitive switch 7, the volume of the space portion 6 can be changed by using a material such as a foam material having a bulk modulus as required. It is preferable to adopt a structure that includes a material such as: In addition to this, when the peripheral part of the pedal rubber 4 is brought into close contact with the pedal body part 3, the response of the pressure-sensitive switch 7 is not only caused by the volume-changeable material sealed therein but also by the enclosed air. Characteristics can be adjusted.

FIG. 4 is a plan view showing another example of arrangement of the switch body. In the example shown in FIG. In this example, one switch structure 5 is formed into a substantially U-shape, and furthermore, as shown in FIG.
) In the example shown in FIG.
The pressure-sensitive switch 7 is arranged in a letter-like shape with a sufficiently low density, and these examples also make it possible to obtain a pressure-sensitive switch 7 at a low cost and having the same effects as those described above.

Fig. 5 is a diagram showing another example of application of this pressure-sensitive switch, and Fig. 5(a) shows the use of the pressure-sensitive switch as a mat for an automatic door.
Figure (b) is used as a touch board in a swimming pool, and Figure 5 (
C) was applied as an exercise counter mat.

Although the present invention has been described above based on the illustrated examples, when the pressure-sensitive switch is installed and used on a hard floor surface, wall surface, etc., the base plate of the pressure-sensitive switch is made of a soft material, for example, the same material as the elastic outer skin. However, it is possible to apply a sufficiently large load reaction force to the switch structure, and for example, if the insulating outer cover, pace plate, and elastic outer cover are all made of silicone rubber, it will have excellent water resistance. -50℃~+100℃
It is possible to provide a pressure-sensitive switch that always operates reliably within a temperature range of .

Furthermore, this pressure-sensitive switch is not limited to the illustrated example, but can be applied particularly as a switch for various uses requiring a relatively large width and length.

(Effects of the Invention) Therefore, according to the present invention, there is no risk of problems caused by having a movable contact, and it has excellent dustproof and waterproof properties.
Moreover, it is possible to provide an inexpensive pressure-sensitive switch that can be applied to various uses and can sensitively respond to loads acting on any part.

[Brief explanation of the drawing]

1 is a diagram showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view illustrating the switch structure, FIG. 3 is a sectional view showing the deformation behavior of the pressure-sensitive switch shown in FIG. FIG. 4 is a sectional view showing another example of arrangement of the switch structure, and FIG. 5 is a diagram showing an example of application of the pressure-sensitive switch. 3...Pedal body part 4...Pedal rubber 5...
・Switch structure 6... Space part 7... Pressure sensitive switch... Pressurized conductive rubber 9... Flexible electrode
10... Insulating outer sheath 11... Lead wire Figure 1 Figure 2 Figure 5 (a) (b) (c)

Claims (1)

[Claims] 1. A base plate, an elastic outer skin disposed at a predetermined interval on one side of the base plate, and having at least a peripheral portion fixed to the base plate, and a base plate disposed between the elastic outer skin and the base plate. a string-like switch structure having a low arrangement density, and a lead wire connected to the switch structure; 1. A pressure-sensitive switch comprising flexible electrodes and an insulating outer cover covering them, and each of the lead wires is connected to a pair of flexible electrodes. 2. The switch according to item 1, wherein the space defined by the base plate, the elastic outer skin, and the switch structure has a volume-changeable material disposed therein. 3. The switch according to item 1, wherein at least a peripheral portion of the elastic outer cover is brought into close contact with the base plate.