JPH05101746A - Limit switch - Google Patents

Abstract

PURPOSE:To provide a limit switch which can realize a single structure, few number of parts, and compact size, and has a long service life and no fear of generating poor operation. CONSTITUTION:A rotation shaft 9 in which a rotation operating member B is pivoted rotatable to a head housing 5, and an actuator 10 to rotation-operate the rotation shaft 9 are provided, a switch C consists of a microswitch 28 housed in a switch housing 3, and the above head housing and the switch housing 3 have been formed integrally, while a cam body 25 to push and operate the push button 29 of the microswitch 28 has been fixed to the above rotation shaft 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a limit switch used in various kinds of production equipment, industrial robots and the like.

[0002]

2. Description of the Related Art Conventionally, as this type of limit switch, the one shown in FIG. 4 has been known. In the figure, 1
Is a switch housing. The switch housing 1 is composed of a switch body 3 containing a switch 2 and a cover 4 for closing a side surface opening 3a thereof, and a plurality of set bolts (not shown) are provided in an upper end opening 3b thereof. The head housing 5 is detachably attached using the head housing 5. A rotary shaft 9 is rotatably supported in the shaft hole 6 of the head housing 5 via a collar 7 and an O-ring 8. One end portion 9a of the rotary shaft 9 is led out of the head housing 5.
Actuator having a roller 12 supported by a shaft 13
The rotor 10 is fitted into one end 9a of the rotary shaft 9 and is fixed by a screw body 11.

The rotary shaft 9 is arranged so that its axis is orthogonal to the axis of the operating rod 22 of the switch 2. The other end 9b of the rotary shaft 9 is positioned on the axis of the operating rod 22. And a flat cam portion 9c is formed. A bottomed cylindrical spring cradle 14 is placed on the cam portion 9c, and a coiled return spring 15 is stretched between the spring cradle 14 and the inner wall surface of the head housing 5 to form the rotary shaft. 9
The rotation return force is applied to.

On the other hand, an operating plunger 16 is interposed between the cam portion 9c and the operating rod 22 of the switch 2, and the operating plunger 16 is fitted in the cylindrical plunger body 17 and the plunger body 17. Auxiliary Plunger 18
And a buffer spring 19 interposed therebetween, and the upper end opening 3b of the switch housing 1
A pusher 20 that pushes the operating rod 22 is fixed to the tip of the auxiliary plunger 18 that is axially movably inserted therethrough. The lower end opening 3c of the switch housing 3 is tightly closed by a connector (not shown) for connecting an electric cable.

In the above structure, when an object to be detected such as a workpiece comes into contact with the roller 12, the actuator 10 integrally rotates about the rotating shaft 9 against the spring force of the return spring 15. Due to the rotational displacement of the actuator 9, the cam portion 9c tilts and presses the operation plunger 16, causing the switch 2 to perform a switching operation. When the cam portion 9c is tilted, the spring receiving base 14 is displaced to compress the return spring 15. When the pressing force of the actuator 9 is released, the spring force of the compressed return spring 15 causes the actuator 9 to return to its original position.

[0006]

By the way, in order to perform the switching operation of the switch 2, the actuator 1 is used.
The rotary motion of 0 must be converted into the linear motion of the operation plunger 16, and the structure of the conversion mechanism is complicated, the number of parts is increased, and not only the entire limit switch is enlarged, but also the sliding part is used. Many and unreasonable stresses act and the life is short.

In order to protect the switch 2 by sealing the internal space of the switch housing 3, the switch housing 1 has a cylindrical elastic seal member 21 at the upper end opening 3b thereof to secure the internal space 1a. It must be shut off airtightly. However, in order for the operation plunger 10 to reciprocate, the volume and pressure in the internal space 1a of the switch housing 1 must be constantly changed, so that the internal space 1a is slightly separated by the elastic seal member 21. Not only is it difficult to maintain the airtightness of the space 1a by performing a breathing operation, but also the return movement deviation occurs in the operation plunger 16 due to the breathing operation of the internal space 1a, and the switching operation of the switch 2 is delayed. ..

The present invention has been made to solve the above problems, and an object thereof is to provide a limited switch which has a simple structure and can be downsized with a small number of parts, has a long life, and is free from the risk of malfunction. To do.

[0009]

A limit switch according to the present invention comprises a rotary shaft having a rotary operation part pivotally supported by a head housing, and an actuator for rotating the rotary shaft. A micro switch housed in a switch housing, a cam body for pressing a push button of the micro switch is fixed to the rotary shaft, and the head housing and the switch housing are integrally formed.

[0010]

According to the above construction, since the micro switch is directly operated by the rotary motion of the rotary shaft, the mechanism for converting the rotary motion of the actuator into the linear motion can be eliminated, and the number of parts can be reduced accordingly. As a result, not only is the entire limit switch miniaturized, but also the push button of the micro switch is pressed by the cam body in the rotary operation part, so that there is no excessive stress and the life is long.

The housing of the limit switch is
Since the switch housing and the head housing are integrally formed, it is possible to easily secure the sealing structure without interposing an elastic seal member between the two housings. Moreover, since there is no mechanism for converting the rotational movement of the actuator into a linear movement, it is possible to eliminate the fluctuations in the volume and pressure in the internal space of the switch housing, and to eliminate the malfunction due to the return movement deviation of the actuator, and to perform the switching. The responsiveness of the operation can be improved.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an example of a limit switch according to the present invention. In the figure, parts that are the same as or correspond to those in FIG. 4 are assigned the same reference numerals, and detailed descriptions thereof are omitted. As shown in the figure, the limit switch is composed of a housing A, a rotation operation part B mounted on the upper part of the housing A, and a switch part C mounted on the lower part thereof.

As clearly shown in FIG. 2, the housing A is composed of a switch housing 3 formed in a tubular shape, and a head housing 5 integrally formed in an opening 3b at one end of the housing 3, A shaft hole 6 of the rotary shaft 9 is formed on one side of the head housing 5. A rotary shaft 9 is rotatably supported in the shaft hole 6 of the head housing 5 through an O-ring 8. One end portion 9a of the rotary shaft 9 is led out of the head housing 5 and the one end portion 9 thereof is
An actuator 10 having a roller 12 supported by a shaft body 13 is fitted in a.

A cam body 25 is attached to the other end 9b of the rotary shaft 9.
Is inserted and fixed. The cam body 25 includes a boss portion 2 having a shaft hole 25a into which the other end 9b of the rotary shaft 9 is inserted.
5b, an arc-shaped spring receiving projection 25c that is concentrically provided on the boss portion 25b at a predetermined interval, and a cam projection 25d that is provided on the outer peripheral surface at a predetermined interval in the circumferential direction. , 25
with e.

As shown in FIG. 3, a coil-shaped return spring 27 is concentrically fitted to the boss portion 25b, and both end portions 27a and 27b of the spring 27 are attached to the inner peripheral surface of the head housing 5. It is locked in the locking groove formed in. As a result, the return spring 27 is stretched between the inner wall surface of the head housing 5 and the cam body 25 to apply a rotation return force to the rotary shaft 9, and
It is held in a neutral state.

The switch portion C comprises a well-known micro switch 28. The switch 28 has a contact mechanism portion (not shown) which is opened and closed by pressing a push button 29 in a switch case and projects into a switch holder 30. The mounting hole 31 of the switch case is fitted into and held by the protrusion 30a provided, and the side opening of the holder 30 is closed by the cover 32. The switch holder 30 is fixed by caulking a protrusion 3d protruding from the inner wall of the switch housing 3 in a mounting hole 30b formed in the switch holder 30.

The switch section C is electrically connected to a printed wiring board 33 in which a predetermined electronic circuit such as a signal processing circuit is incorporated. That is, the printed circuit board 33 is mounted with the element 34 and the operation display light emitting element 35 that form an electronic circuit, and the cable 36 is reconnected.
It is led to the outside of the switch housing 3 via a lead wire 37. Further, the switch housing 3 is filled with an electrically insulating synthetic resin 38 (marked by x), and the terminal portion 39 of the micro switch 28 is resin-molded. Further, the lower end opening 3 of the switch housing 3
A cover 40 is fitted to c.

Next, the operation of the above configuration will be described. Now, as shown in FIG. 3, when a moving object D such as a dog comes into contact with the roller 12, the actuator 10 rotates to either the left or the right (directions of arrows a and b). After that, the rotary shaft 9 also rotates in the same direction as the cam body 25. By the rotational movement of the cam body 25, the cam projection piece 25d or 26e abuts the push button 29 of the micro switch 28, opens and closes the internal contact mechanism portion, and outputs the detection signal via the signal processing circuit. At the same time, the detection operation can be visually confirmed by the light emission of the light emitting element 35.

According to the above construction, the switch portion C is directly operated for switching without converting the rotational movement of the rotary shaft 9 into the linear movement. Therefore, a mechanism portion for converting the rotational movement of the actuator 10 into the linear movement is provided. Can be lost
Not only is the number of parts reduced, the size of the entire limit switch is reduced, but also the push button 29 of the micro switch 28 is pressed by the cam body 25 in the rotary operation part B, so that there is no excessive stress and the life is long. ..

Further, since the housing A is formed by integrally forming the switch housing 3 and the head housing 5, the housing A can be easily sealed without interposing an elastic seal member between the housings 3 and 5. The structure can be secured. In that case, the sealing effect can be further improved by filling the lower end opening 3c of the switch housing 3 with the synthetic resin 43 and resin-molding the terminal portion 39 of the switch portion C. Moreover, since there is no mechanism for converting the rotational movement of the actuator 10 into a linear movement, it is possible to eliminate the fluctuations in volume and pressure in the internal space of the switch housing 3, and thus the actuator 1
It is possible to improve the responsiveness of the switching operation by eliminating the operation failure due to the deviation of the return operation of 0.

In the above embodiment, a side opening (not shown) similar to the opening 3a of the conventional example shown in FIG. 4 is provided on one side of the switch housing 3, and the side opening is closed by a cover. Even if it does, the same effect can be produced.

[0022]

As described above, according to the present invention, it is possible to provide a limited switch which has a simple structure and can be miniaturized with a small number of parts, has a long life, and is free from the risk of malfunction.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment according to the present invention.

FIG. 2 is a side view showing a notch of a main part of the embodiment.

FIG. 3 is a front view showing a notch of a main part of the embodiment.

FIG. 4 is a side view showing a notch of a main part of a conventional limit switch.

[Explanation of symbols]

 A housing B rotation operation part C switch part 3 switch housing 3b upper end opening 3c lower end opening 5 head housing 9 rotating shaft 10 actuator 28 micro switch 29 push button 43 mold resin

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 20, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

A limit switch according to the present invention comprises a rotary shaft having a rotary operation part pivotally supported by a head housing, and an actuator for rotating the rotary shaft. It consists of a micro switch housed in a switch housing, and a cam body for pressing the push button of this micro switch is fixed to the rotary shaft.
Wherein the constant was.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

Further, because there is no mechanism for converting rotary motion of A Kuchiyueta into linear motion, there is no change in volume or pressure in the interior space of the Sui Tutsi housing, the inner space
You can eliminate the breathing effect between. Therefore, within the above
The seat of the switch housing is based on the breathing action of the subspace.
It is possible to prevent deterioration of the Le performance and Reona comb not a return operation of the actuator, it is possible to enhance the responsiveness of the switching-operation.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Next, the operation of the above configuration will be described. Now, as shown in FIG. 3, when a moving object D such as a dog comes into contact with the roller 12, the actuator 10 rotates to either the left or right (directions of arrows a and b). The rotary shaft 9 also rotates together with the cam body 25 in the same direction. The pivoting movement of the cam member 25, the cam protrusion 25d or 26e is brought into contact with the push button 29 of the microswitch 28, thereby opening and closing the internal contact mechanism, on the detection signal
The output can be output through a predetermined electronic circuit incorporated in the printed wiring board 33, and the detection operation can be visually confirmed by the light emission of the light emitting element 35.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

Further, since the housing A is constructed by integrally forming the switch housing 3 and the head housing 5, the housing A can be easily sealed without interposing an elastic seal member between the housings 3 and 5. The structure can be secured. In that case, the sealing effect can be further improved by filling the lower end opening 3c of the switch housing 3 with the synthetic resin 43 and resin-molding the terminal portion 39 of the switch portion C. Moreover, since there is no mechanism for converting the rotational movement of the actuator 10 into a linear movement, there is no change in volume or pressure in the internal space of the switch housing 3, and the breathing action of the internal space is eliminated.
You can Therefore, due to the breathing action of the internal space
Prevents deterioration of sealing performance of the drop switch housing
It is possible, by eliminating Re not a return operation <br/> the actuator, it is possible to enhance the responsiveness of the switching-operation. In particular, inside the switch housing 3
Even if the above
Both housings 3 and 5 are constructed separately as in the past,
Even if an elastic seal member is interposed between them,
Sealability in the internal space of the switch housing 3
It is possible to effectively prevent a decrease in performance.

Claims (4)

[Claims] 1. A limit switch having a rotary operation part on an upper part and a switch part on a lower part, wherein the rotary operation part includes a rotary shaft rotatably supported by a head housing, and an actuator for rotating the rotary shaft. The switch part comprises a micro switch housed in a switch housing, and a cam body for pressing a push button of the micro switch is fixed to the rotary shaft, and the head housing and the switch housing are integrally formed. Limit switch. 2. The limit switch according to claim 1, wherein said switch housing is formed in a tubular shape, a head housing is integrally formed at an upper end opening portion thereof, and a lower end opening portion thereof is closed by a cover. 3. The switch housing is provided with an opening on one side surface of a cylinder, a head housing is integrally formed on an upper end opening, and the side surface opening and the lower end opening are closed by a cover. The limit switch according to item 1. 4. The limit switch according to claim 1, wherein a synthetic resin is filled into a lower end opening of the switch housing, and a terminal portion of the switch portion is resin-molded.