JPH0646531B2 - Stroke switch installation structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stroke switch installation structure suitable for use when an object to be measured can generate heat.

[Conventional technology and its problems]

Although various types of stroke switches are known, they are generally mounted in a recess so as to face an object to be measured. Therefore, the measured object is, for example,
If the brake pad or the like is capable of generating heat, a large amount of heat is transferred to the switch, and the switch may be thermally deformed or destroyed.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, and an object thereof is to provide a stroke switch installation structure capable of preventing heat transfer.

[Means for solving problems]

The object is to provide a movable contact on a plunger that can be contacted with a detected object that can generate heat and that is biased toward the detected object by a spring, and to provide a pair of fixed contacts facing the movable contact. A stroke switch movably housed inside the main body so that the movable contact comes into contact with the pair of fixed contacts to connect or disconnect between the pair of fixed contacts when the plunger moves by a predetermined value. In a stroke switch installation structure that is fixed and arranged in a recess provided opposite to a detection object, the movable contact and the fixed contact are surrounded between the outer periphery of the main body and the inner wall of the recess. This is achieved by a stroke switch installation structure in which a heat insulating annular cavity is formed.

[Action]

The heat generated by the object to be measured or the object to be detected is cut off by the heat insulating annular space and is hardly transmitted to the stroke switch in the main body, that is, the movable contact and the fixed contact. Therefore, thermal deformation or breakage of the stroke switch is prevented.

〔Example〕

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the stroke switch installation structure of the first embodiment. In the figure, the stroke switch is indicated by (1) as a whole, and a stationary body, for example, a stationary portion (2) of a disc brake.
It is mounted in the recess (3) of the and faces the pad (4) as the object to be detected. When a vehicle equipped with the disc brake brakes on an uphill road and stops, the pad (4) moves to the right in the figure as disclosed by the applicant. Reference numeral (5) is an abutting plate that determines the stop position of the pad (4) and is attached to the stationary portion (2). That is, the gap S between the pad (4) and the contact plate (5) is the pad (4).
Defines the stroke of.

The main body (6) of the stroke switch (1) has a tubular shape, and the retaining ring (7) prevents the stroke switch (1) from coming off the recess (3). A plunger (8) is slidably fitted in the stepped hole (9) in the body (6).
A rubber boot (10) is fixed to the left end of (6). A screw (8a) is formed at the tip of the plunger (8), and the cap (11) is screwed to the cap (11) with its inner screw (11b). An air chamber (20) is formed between the cap (11) and the top of the plunger (8), which is the cap.
It communicates with the atmosphere through a small hole (11a) formed in the peripheral wall of (11). In the figure, the right end face of the cap (11) is the plunger.
Although it is in the right limit position by abutting on the step formed at the left end of (8), it comes from the opening (5a) of the abutment plate (5) according to a predetermined stroke of the pad (4) by screw engagement. The amount of protrusion is adjustable.

A recess (8b) is formed at the right end of the plunger (8), and a spring (13) is stretched over this to urge the cup-shaped movable contact member (12) to the right. The right side position of the movable contact member (12) is regulated by the flange portion (12a) of the movable contact member (12) contacting the left end flange portion (8c) of the plunger (8). The plunger (8) is also biased to the left by a spring (15) stretched between the plunger and the contact support plate (14) made of an insulating material, and the stepped portion of the body (6) is shown in the figure. By contacting the stepped portion of the stepped hole (9), its left position is restricted.

The contact support plate (14) supports the fixed contacts (17a) (17b),
Lead wires (16a) and (16b) are connected to these contacts (17a) and (17b). (18) is a molding material, which is molded so as to protect the connecting portions between the contacts (17a) (17b) and the lead wires (16a) (16b) from the outside.

An annular recess on the outer circumference of the body (6) of the stroke switch (1)
(6a) is formed, and the body (6) has flanges (6b) on both sides.
It is fitted in the recess (3) of the stationary part (2) at (6c). Annular recess (6
a) is an air chamber, which extends to the left and right so as to surround the movable contact member (12) and the fixed contacts (17a) and (17b) as shown in the figure, and the air has a heat insulating effect, so that the stationary portion It works by blocking the transfer of heat from (2) into the body (6).
In particular, heat is prevented from being transferred to the movable contact member (12) and the fixed contacts (17a) and (17b), so that these contacts are protected.
An air chamber (20) is also formed between the tip of the plunger (8) and the cap (11), which also suppresses heat transfer from the pad (4) to the plunger (8) side. Work hard.

The first embodiment of the present invention is configured as described above. Next, its operation, effect, etc. will be described.

When a vehicle equipped with this structure brakes and stops on an uphill road, the pad plate (4) moves to the right in the figure. As a result, the cap (11) at the tip of the stroke switch (1) is pushed to the right, and with this, the plunger
(8) also moves to the right against the spring force of the spring (15). The movable contact member (12) moves rightward together with the plunger (8) by a spring (13) stretched between the movable contact member (12) and the plunger (8), and comes into contact with the fixed contacts (17a) (17b). As a result, these contacts (17a) and (17b), that is, the lead wires (16a) and (16b) are electrically connected to each other to excite a solenoid of a solenoid valve for holding a braking force, for example, although not shown. Movable contact member
After contacting the fixed contacts (17a) and (17b) with the (12),
Only (8) moves to the right, and the right end flange portion (8c) separates from the flange portion (12a) of the movable contact member (12). The stroke of the pad plate (4) is restricted by contact with the contact plate (5), and the movement of the plunger (8) is also stopped by this. After the movable contact member (12) contacts the fixed contacts (17a) and (17b), only the plunger (8) moves so that the pressing force of the pad plate (4) is not directly received. The load is prevented from being applied. That is, the switch contacts are protected from excessive loads.

When the vehicle is operated to start, the pad plate (4) moves to the left and assumes the position shown. Plunger (8) is spring
The spring force of (15) causes the pad plate (4) to move to the left, and at this time, the movable contact member (12) is hooked by the flange portion (8c) and separated from the fixed contacts (17a) and (17b). As a result, the lead wires (16a) and (16b) are electrically cut off from each other.
Therefore, for example, the solenoid of the solenoid valve (not shown) is not excited.

The present embodiment performs the above-mentioned actions, but has the following remarkable effects.

When the vehicle is braked, a large amount of heat is generated on the pad plate (4) due to friction. This is also transmitted to the stationary part (2) of the disc brake, which also becomes high heat. However, according to this embodiment, since the annular space (6a) is formed between the stationary portion (2) and the switch body (6), the annular space (6a) is also formed.
Since (a) extends so as to surround the movable contact member (12) and the fixed contacts (17a) (17b), heat is not transferred from the static portion (2) into the main body (6) from this air. Is prevented. In particular, heat is prevented from being transferred to the movable contact member (12) and the fixed contacts (17a) and (17b). On the other hand, heat transfer from the pad plate (4) to the plunger (8) can also be suppressed by the air in the air chamber (20) in the cap (11). If the cap (11) is made of a heat insulating material, heat transfer can be sufficiently prevented. As described above, the switch structure in the main body (6), especially the movable contact (12) and the fixed contacts (17a, 17b) are prevented from being thermally deformed or broken.

Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, parts corresponding to those in FIG. 1 are designated by the same reference numerals.

In the figure, the stroke switch is indicated as a whole by (21), the plunger (28) is slidably fitted in the stepped hole (29) in the main body (36), and the left end is insulated by heat. The actuating pin (31) made of material is fixed. A rubber boot (30) is fixed between the operating pin (31) and the left end of the body (36).

An annular recess (28b) is formed in the middle of the plunger (28),
A spring (33) is stretched over this and urges the annular movable contact member (32) to the right. The right side position of the movable contact member (32) is regulated by the flange portion (32a) of the movable contact member (32) contacting the left end flange portion (28c) of the plunger (28). The plunger (28) is biased to the left by a spring (35) stretched between the plunger (28) and a contact support member (34) made of an insulating material, and is fixed to the distal end of the operating pin (31). The contact with the pad plate (4) restricts its left position.

The contact support member (34) supports fixed contacts (37a) (37b) (37c) (37d), and these contacts (37a) (37b) (37c) (37d) have lead wires (36a) (36b). ) (36c) (36d) are connected. Reference numeral (38) is a molding material, which is molded so as to protect the connecting portions between the contacts (37a) to (37d) and the lead wires (36a) to (36d) from the outside.

Stroke switch (21) body (36) circumference and rest
The annular space between the inner wall of (2) and the inner wall is made of a heat insulating material, and the movable contact member (32) and the fixed contacts (37a) (37b) (37c) and (37d)
A cylindrical member (50) extending so as to surround the space is filled to prevent heat from being transferred from the stationary portion (2) into the main body (36).

In this embodiment, four lead wires (36a) to (36d) are led out. In the above-mentioned embodiment, two are led out and connected to the solenoid of the solenoid valve, but in this embodiment, the other two are connected.
The lead of the book may be connected, for example, to the lamp to indicate that the switch is indeed active.

The second embodiment is configured as described above, but the operation, effect, etc. are almost the same as those of the first embodiment, so a detailed description thereof will be omitted. However, the heat insulating effect has the following different effect. ing.

That is, in this embodiment, the cylindrical member (50) made of a heat insulating material is provided around the main body (36) so that the movable contact member (32) and the fixed contact (37a).
Since (37b), (37c) and (37d) are arranged and filled so as to surround them, more effective heat insulating action can be performed than in the case of the air of the first embodiment. Also a pad board
Since the actuating pin (31) that is in direct contact with (4) is made of a heat insulating material, direct heat transfer from the pad plate (4) can be further reduced. In the first embodiment, the material of the cap (11) is not specified, but of course, it may be formed of a heat insulating material.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the disc brake pad is described as the detected object detected by the stroke switch, but instead of this, the present invention is also applied to detect the stroke of the anchor having the sliding portion of the drum brake. It is possible. Further, the present invention is not limited to these, and can be applied to a detected object that can generally generate heat.

〔The invention's effect〕

As described above, according to the stroke switch installation structure of the present invention, heat transfer to the stroke switch can be prevented, and deformation or breakage due to heat can be prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view of a stroke switch installation structure according to a first embodiment of the present invention, FIG. 2 is a side sectional view of a stroke switch installation structure according to the second embodiment, and FIG.
It is a rear view of the structure of a figure. In the figure, (6) (36) ...... main body (6a) ...... annular recess (50) ...... tubular member

Claims (2)

[Claims] 1. A movable contact is provided on a plunger that is capable of abutting against an object that can generate heat and is urged toward the object by a spring. A pair of fixed contacts are provided facing the movable contact. A stroke switch movably housed inside the main body so that the movable contact comes into contact with the pair of fixed contacts to connect or disconnect between the pair of fixed contacts when the plunger moves a predetermined value. In a stroke switch installation structure which is fixed and arranged in a recess provided to face the detected object, the movable contact and the fixed contact are surrounded between an outer periphery of the main body and an inner wall of the recess. Stroke switch installation structure that forms an annular space for heat insulation. 2. The stroke switch installation structure according to claim 1, wherein the heat insulating annular space is filled with a heat insulating material.