JPH05109344A - Limit switch - Google Patents

Abstract

PURPOSE:To provide a limit switch with simple structure and a small number of part items resulting in its miniaturization, having a long life and without hear of malfunction. CONSTITUTION:A rotation shaft 9 such that a rotation operating par B is rotatably pivoted to a head housing 5, and an actuator 10 for rotating-operating the rotation shaft 9 are provided. A switch part C consists of a detector 29 housed in a switch housing 3 and detecting objects 27a and 27b to be detected set on the outside peripheral surface of a cam body 25 fixed on the rotation shaft 9, in a contactless manner, to generate a detection signal, and the head housing 5 is integrated with the switch housing 3.

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. 9 is 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. The head housing and the switch housing are composed of a detector that detects the object to be detected, which is housed in the switch housing and fixed on the outer peripheral surface of the cam body, which is set on the outer peripheral surface of the cam body in a contactless manner. It is characterized by being integrally formed.

[0010]

According to the above construction, since the rotational movement of the rotary shaft is directly detected by the detector, it is possible to eliminate the mechanism portion for converting the rotational movement of the actuator into the linear movement, and the number of parts is reduced accordingly. Not only is the size of the limit switch reduced and the size of the limit switch is reduced, but since the rotary operation unit and the detector are not in contact with each other, excessive stress does not act 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]

【Example】

Example 1. Embodiments of the present invention will be described below 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. 9 are given the same reference numerals, and detailed description thereof is 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 FIGS. 2 and 3, the housing A includes 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 for 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 to the outside of the head housing 5, and the one end portion 9a is attached to the one end portion 9a. The actuator 10 having the roller 12 supported by the shaft body 13 is fitted through the spacer 55 and fixed by the screw body 11.

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 in the circumferential direction. On the outer peripheral surface of the cam projecting piece 25d, a pair of conductive detection objects 27a and 27b are attached at a predetermined interval in the circumferential direction.

A coil-shaped return spring 26 is concentrically fitted to the boss portion 25b, and both end portions 26a and 26b of the spring 26 are locking grooves formed on the inner peripheral surface of the head housing 5. Is locked to. As a result, the return spring 26 is stretched between the inner wall surface of the head housing 5 and the cam body 25, urges a rotational return force to the rotary shaft 9, and is held in a neutral state.

The internal switch C is composed of a proximity switch, and the proximity switch includes a switch case 28,
It is composed of a detector 29 mounted on the inner surface of the case 28 and a printed wiring board 30, and the printed wiring board 30 incorporates predetermined electronic circuits such as an oscillation circuit and a signal processing circuit. The printed wiring board 30 includes an element 34 that constitutes an electronic circuit and an operation display light emitting element 54.
Is attached and the cover 3 is attached via the lead wire 31.
The connector 37 fitted in 6 is the printed wiring board 3 described above.
It is electrically connected to the lead pattern of 0 and is led out from the lower end opening 3c of the switch housing 3.
Further, the switch housing 3 is filled with an electrically insulating synthetic resin 38, and the detector 29, the printed wiring board 30 and the like are resin-molded.

As shown clearly in FIG. 4, the detector 29 is constructed by fitting a core 43 made of a magnetic material having an annular recess 43a into a coil spool 41 around which a detection coil 42 is wound. There is. That is, the detection coil 42 wound around the coil spool 41 is fitted into the annular recess 43a of the core 43, and the oscillation circuit provided on the printed wiring board 30 via the lead wire 42a of the coil 42, It is electrically connected to a predetermined electronic circuit such as a signal processing circuit.

Next, the operation of the above configuration will be described. Now, when a moving object comes into contact with the roller 12, the actuator
2, the rotary shaft 9 rotates with the cam portion 25 in the same direction. Due to the rotational movement of the cam body 25, the objects to be detected 27a, 27b attached thereto approach the detection coil 42 shown in FIG. 4, the change in the inductance thereof is detected by the oscillation circuit, and the detection signal is signal processed. The output can be output through the circuit and the detection operation can be visually confirmed by the light emission of the light emitting element 54.

According to the above construction, since the proximity switch C is directly operated by the rotary motion of the rotary shaft 9,
It is possible to eliminate the mechanism section that converts the rotary motion of the actuator 10 into a linear motion, and the number of parts is reduced accordingly, and not only the entire limit switch is downsized, but also the rotary operation part B and the proximity switch C are contactless. Therefore, it has a long life without exerting excessive stress.

In addition, the housing A of the limit switch
Is formed by integrally forming the switch housing 3 and the head housing 5, so that both housings 3, 5
Even if the elastic seal member is not interposed between the two, it is possible to easily secure the sealing structure. In this case, the sealing effect can be further improved by filling the synthetic resin 43 into the other end opening 3c of the switch housing 3 and resin-molding it. 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 fluctuation of the volume and pressure in the internal space of the switch housing 3, and to eliminate the malfunction caused by the deviation of the returning movement of the actuator 10. Thus, the responsiveness of the switching operation can be improved.

Example 2. Although the case where the switch portion C is the proximity switch has been described in the first embodiment, the switch portion C can be configured by a transmission type photoelectric switch as shown in FIG. That is, the photoelectric switch is formed in the case 28 by accommodating the detector 29 in which the light emitting element 47 and the light receiving element 48 are arranged to face each other in the switch case 28 in which the U-shaped recess 28a is formed. The light 60 is transmitted and received through the through holes 49 and 50 as shown in FIG. On the other hand,
A light blocking plate 46 for blocking the light 60 is provided in the recess 28a.
Are rotatably arranged and project from a cam body 25 fixed to the other end 9b of the rotary shaft 9, and a pair of through holes are formed in the light shielding plate 46 at a predetermined interval in the circumferential direction. 46a, 46b
Are formed.

In the above structure, the moving object is the roller 12
When the actuator 10 is rotated, the light shielding plate 42
Is rotated to the left or right (in the directions of arrows a and b), the light 60 passes through the through holes 46a and 46b of the light shielding plate 46, is irradiated to the light receiving element 48, and the signal on the printed wiring board 30 is transmitted. The detection signal is output via the processing circuit.

Example 3. The switch part C may be configured by setting a detector 29 including a magnetoelectric conversion element 52 such as a Hall element on the printed wiring board 30 as shown in FIG. 7. That is, the magnet 51 for accommodating the magnetoelectric conversion element 52 in the switch case 28 and energizing the magnetic flux to the magnetoelectric conversion element 52 is the other end 9 of the rotary shaft 9.
It is attached to a cam body 25 fixed to b. In the above structure, a moving object comes into contact with the roller 12 and the magnet 51 is rotated by the rotation of the actuator 10, whereby a detection signal is sent to the magnetoelectric conversion element 52 and a signal processing circuit in the printed wiring board 30. Is output via.

Example 4. The limit switch is
The la 12 may be configured to be pressed by the dock D. Further, in the embodiment using this dock D, the case where the switch portion C uses the same proximity switch as in the first embodiment is described, but as described above, the photoelectric switch or the magnetoelectric conversion element may be used. Needless to say.

Example 5. In each of the above examples,
Provided on one side surface of the switch housing 3 is a side opening (not shown) similar to the opening 3a of the conventional example in FIG. 9, and even if the side opening is closed with a cover, the same effect can be obtained. You can

[0026]

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 a first embodiment according to the present invention.

FIG. 2 is a front view showing a notched part of a first embodiment.

FIG. 3 is a side view showing a notched part of a first embodiment.

FIG. 4 is an enlarged cross-sectional view showing a main part of the first embodiment.

FIG. 5 is a side view showing a notched part of a second embodiment.

FIG. 6 is an enlarged perspective view showing a main part of the second embodiment.

FIG. 7 is a side view showing a notched part of a third embodiment.

FIG. 8 is a front view showing a notched part of a fourth embodiment.

FIG. 9 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 top opening 3c bottom opening 5 head housing 9 rotating shaft 10 actuator 29 detector 38 mold resin

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[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. housed in Sui Tutsi housing and wherein the ing from the detector for generating a detection signal by detecting the object to be detected in a contactless set in the outer peripheral surface of the fixed cam to the rotary shaft.

[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, when a moving object comes into contact with the roller 12, the actuator 10 rotates to either the left or right (direction of arrows a and b) shown in FIG. 2, and along with this, the rotary shaft 9 together with the cam body 25. Rotate in the same direction. Due to the rotational movement of the cam body 25, the objects to be detected 27a, 27b attached thereto approach the detection coil 42 shown in FIG. 4, the change in the inductance is detected by the oscillation circuit, and the detection signal is printed as described above.
The output can be output through a predetermined electronic circuit incorporated in the wiring board 30, and the detection operation can be visually confirmed by the light emission of the light emitting element 40.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

In addition, the housing A of the limit switch
Is formed by integrally forming the switch housing 3 and the head housing 5, so that both housings 3, 5
Even if the elastic seal member is not interposed between the two, it is possible to easily secure the sealing structure. In this case, the sealing effect can be further improved by filling the synthetic resin 43 into the other end opening 3c of the switch housing 3 and resin-molding it. 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 can be eliminated.
It For this reason, it is possible to switch the
It is possible to prevent deterioration of the sealing performance of the housing.
With wear, and Re to Do <br/> comb not a return operation of the actuator, it is possible to enhance the responsiveness of the switching-operation. Especially, in the inner space of the switch housing 3,
It is possible to eliminate the respiratory effect of
The rings 3 and 5 are constructed separately as in the conventional case, and both
Even if an elastic seal member is installed between
Deterioration of sealing performance in the inner space of the housing 3
Can be effectively prevented.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

In the above structure, the moving object is the roller 12
Contact with, the light shielding plate 4 6 rotation of actuator 10
Is rotated to the left or right (in the directions of arrows a and b), the light 60 passes through the through holes 46a and 46b of the light shielding plate 46, is irradiated to the light receiving element 48, and is incorporated in the printed wiring board 30. The detection signal is output via the predetermined electronic circuit .

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Delete

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 is a detector that is housed in a switch housing and that detects the object to be detected set on the outer peripheral surface of the cam body that is fixed to the rotating shaft in a non-contact manner and generates a detection signal,
A limit switch characterized in that the head housing and the switch housing are integrally formed. 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.