阅读说明：本技术 螺线管的驱动控制装置及具备该驱动控制装置的安全开关 (Drive control device for solenoid and safety switch provided with same ) 是由 釜谷拓次 本田贵志 于 2020-04-21 设计创作，主要内容包括：能够实现节能并且能够降低因温度升高而引起的热风险。螺线管的驱动控制装置100以如下方式构成：具有对可动铁心23A进行吸引的螺线管主体22A,螺线管主体22A将可动铁心23A支承为能够移动,以使得可动铁心23A能够实现被螺线管主体22A吸引的吸引位置和未被螺线管主体22A吸引的非吸引位置。设置有：光断续器28,其对可动铁心23A的状态进行检测；以及电流控制部51,其与光断续器28的检测结果相应地控制向螺线管主体22A的供给电流,以便在可动铁心23A处于非吸引位置或其附近位置的状态下向螺线管主体22A供给驱动电流Imax,在可动铁心23A处于吸引位置或其附近位置的状态下向螺线管主体22A供给小于驱动电流Imax的保持电流Ih。(Energy saving can be achieved and the thermal risk due to temperature increase can be reduced. The drive control device 100 for the solenoid is configured as follows: the solenoid body 22A includes a solenoid body 22A that attracts the movable core 23A, and the solenoid body 22A movably supports the movable core 23A such that the movable core 23A can assume an attracting position where the movable core is attracted by the solenoid body 22A and a non-attracting position where the movable core is not attracted by the solenoid body 22A. Is provided with: a photointerrupter 28 for detecting the state of the movable core 23A; and a current control unit 51 for controlling the supply current to the solenoid body 22A in accordance with the detection result of the photo-interrupter 28 so as to supply the drive current Imax to the solenoid body 22A in a state where the movable core 23A is at the non-attracting position or the position near the non-attracting position, and so as to supply the holding current Ih smaller than the drive current Imax to the solenoid body 22A in a state where the movable core 23A is at the attracting position or the position near the attracting position.)

1. A drive control device for a solenoid, having a solenoid main body for attracting a movable part, the solenoid main body supporting the movable part movably so that the movable part can realize an attraction position attracted by the solenoid main body and a non-attraction position not attracted by the solenoid main body,

it is characterized in that the preparation method is characterized in that,

the drive control device for the solenoid includes:

a detection unit that detects a state of the movable unit; and

and a current control unit that controls a current to be supplied to the solenoid main body in accordance with a detection result of the detection unit so that a 1 st current is supplied to the solenoid main body in a state where the movable unit is at the non-attraction position or a position near the non-attraction position, and a 2 nd current smaller than the 1 st current is supplied to the solenoid main body in a state where the movable unit is at the attraction position or a position near the attraction position.

2. The drive control apparatus of a solenoid according to claim 1,

the movable unit is provided with a movable body that moves by receiving an action from the movable unit, and the movable body is provided with an action unit that acts on a contact for controlling an external device and a detection unit that is detected by the detection unit.

3. The drive control apparatus of a solenoid according to claim 1,

the detection unit detects that the movable unit is at the non-attracting position or a position near the non-attracting position, and when the detection unit fails, the current control unit supplies the 1 st current to the solenoid main body.

4. A safety switch having the drive control device of the solenoid according to claim 1,

the safety switch is provided with:

a switch body having contacts;

an actuator that is inserted into and removed from the switch main body; and

a cam rotatable by insertion of the actuator,

the movable portion of the solenoid functions to lock or unlock the rotation of the cam.

5. The safety switch according to claim 4,

the movable part has a movable body which moves by the action of the movable part,

the moving body includes: an action portion that exerts an action on the contact of the switch main body; and a detection section that detects the detection by the detection section.

Technical Field

The present invention relates to a drive control device for a solenoid for achieving energy saving and reducing a thermal risk due to a temperature rise, and a safety switch provided with the drive control device.

Background

Generally, a solenoid includes: a solenoid body having an electromagnetic coil; and a movable part slidably supported by the solenoid body. When current is applied to the electromagnetic coil, a magnetic field passing through the movable portion is generated by the electromagnetic coil, and the movable portion is attracted to the solenoid main body by the magnetic force.

Here, the magnetic force is inversely proportional to the square of the distance, and therefore, in the solenoid, a large current (drive current) is required when attracting the movable portion, but after attracting the movable portion, the movable portion enters the magnetic field, and the same current, but a small current (holding current), is not required.

However, in the conventional solenoid, the same current as that in the attraction is continuously supplied even when the movable portion is held after the attraction, and therefore, power consumption increases, the solenoid generates heat to adversely affect surrounding equipment, or when the solenoid is installed in a place where a person approaches, the solenoid may generate heat to cause damage to a human body. In addition, there is a risk of burning of the electromagnetic coil.

Therefore, in the energization control method of the solenoid described in japanese patent application laid-open No. 2000-173822, when the energization switch for the coil is turned on, the full current is supplied to the coil, and after a predetermined time has elapsed from the start of energization, the energization current to the coil is kept at a small value by the current limiting circuit (see paragraphs [0046] to [0048] of the publication). According to the publication, the following is described: with this configuration, power saving of the solenoid can be achieved, the amount of heat generated can be reduced, and burning of the coil does not occur.

On the other hand, a safety switch is known as a device using a solenoid. The safety switch is the following switch: the door opening/closing device is provided at an entrance of a dangerous area where a machine tool or the like is disposed, and is turned on/off according to an open/close state of a door, and includes: an actuator mounted on the door side; and a switch main body installed at a wall side and used for inserting and pulling the actuator. The switch main body is provided with: a cam rotatable by insertion of the actuator; and an operating lever which is movable in the axial direction, and one end of which is provided so as to be capable of abutting against the cam and the other end of which is provided so as to be capable of switching the contact point; and a solenoid disposed around the operating rod. When the movable door is opened and closed, the actuator moving together with the movable door is inserted into and pulled out from the switch body, the cam inside the switch body is rotated, and the operating lever is moved in the axial direction in accordance with the rotational position of the cam, and accordingly, the on/off of the contact is switched and an on/off signal is transmitted to the machine tool. The solenoid of the safety switch is provided for the following purposes: the locking/unlocking of the cam is switched by sucking and moving the operating lever when the movable door is opened or closed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2000-173822 (see paragraphs [0046] to [0048])

Disclosure of Invention

In the conventional energization control of the solenoid of such a safety switch, even when the attraction state of the operation lever is maintained after the attraction of the operation lever, the same current as that in the attraction of the operation lever continues to flow, and therefore, there are the same problems of the increase in power consumption and the heat risk due to the heat generation of the coil as described above. Therefore, the following scheme is also considered: in the method described in the above publication, after a predetermined time has elapsed after the current is supplied to the solenoid, the current is switched from a large current (drive current) to a small current (hold current) at the time of current supply.

However, in the case of the safety switch, if the operation of sucking the operation lever is not completed until the predetermined time elapses, there is a possibility that a locking failure or an unlocking failure of the safety switch occurs. Thus, it can be said that: the energization control based on time is not suitable for a solenoid that operates a device such as a safety switch.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a drive control device for a solenoid, which can save energy and reduce a thermal risk due to a temperature increase. Another object of the present invention is to provide a drive control device for a solenoid, which can reliably lock and unlock a safety switch.

The present invention relates to a drive control device for a solenoid, including a solenoid main body for attracting a movable portion, wherein the solenoid main body movably supports the movable portion so that the movable portion can realize an attraction position where the movable portion is attracted by the solenoid main body and a non-attraction position where the movable portion is not attracted by the solenoid main body. The device is provided with: a detection unit that detects a state of the movable unit; and a current control unit that controls a current supplied to the solenoid body in accordance with a detection result of the detection unit so that a 1 st current is supplied to the solenoid body in a state where the movable unit is at the non-attraction position or a position near the non-attraction position, and a 2 nd current smaller than the 1 st current is supplied to the solenoid body in a state where the movable unit is at the attraction position or a position near the attraction position.

According to the present invention, the movable portion moves to the attraction position when attracted by the solenoid main body and moves to the non-attraction position when not attracted by the solenoid main body. At this time, the state of the movable portion is detected by the detection portion. The current control unit controls the current supplied to the solenoid body in accordance with the detection result of the detection unit, so that the 1 st current is supplied to the solenoid body in a state where the movable unit is at the non-attraction position or at a position near the non-attraction position, and the 2 nd current smaller than the 1 st current is supplied to the solenoid body in a state where the movable unit is at the attraction position or at a position near the attraction position.

Accordingly, when the movable portion is at the attraction position or a position near the attraction position, the current supplied to the solenoid main body is reduced, and the current consumption of the solenoid is reduced, so that energy can be saved by saving electricity, and the temperature rise can be reduced, thereby reducing the risk of heat such as burning of the coil.

In the present invention, the movable unit is provided with a movable body that moves by receiving an action from the movable unit, and the movable body is provided with an action unit that acts on a contact for controlling an external device and a detection unit that is detected by the detection unit.

In the present invention, the detection unit detects that the movable unit is at the non-attraction position or a position near the non-attraction position, and when the detection unit fails, the 1 st current is supplied to the solenoid main body by the current control unit.

The present invention relates to a safety switch including the drive control device, and including: a switch body having contacts; an actuator that is inserted into and removed from the switch main body; and a cam that can be rotated by insertion of the actuator, and a movable portion of the solenoid functions to lock or unlock rotation of the cam.

In the present invention, the movable unit has a movable body that moves by receiving an action from the movable unit, and the movable body includes: an action part acting on the contact of the switch main body; and a detection section which is detected by the detection section.

As described above, according to the present invention, when the movable portion is at the attraction position or the position near the attraction position, the current supplied to the solenoid main body is reduced to reduce the current consumption of the solenoid, whereby energy saving due to power saving can be achieved, and the temperature rise can be reduced to reduce the risk of heat such as burning of the coil.

Drawings

Fig. 1 is an exploded assembly view of a switch main body of a safety switch to which a solenoid drive control device according to an embodiment of the present invention is applied.

Fig. 2 is a longitudinal sectional view of a switch body of a latch type safety switch as an example of the safety switch (fig. 1).

Fig. 3 is a perspective view of the contact switching block (movable body) of the switch main body (fig. 1) as viewed from above.

Fig. 4 is a perspective view of the contact switching block (fig. 3) as viewed from below.

Fig. 5 is a top view of the contact switching block (fig. 3).

Fig. 6 is a front view of the contact switching block (fig. 3).

Fig. 7 is a schematic block diagram of the drive control device (fig. 1).

Fig. 8 is a time-series diagram showing an operation of the safety switch (fig. 2) when the actuator is disengaged.

Fig. 9 is a time-series diagram showing an operation of the safety switch (fig. 2) when the actuator is disengaged.

Fig. 10 is a time-series diagram showing an operation of the safety switch (fig. 2) when the actuator is disengaged.

Fig. 11 is a graph showing a change in solenoid current controlled by the drive control device (fig. 7).

Fig. 12 is a diagram showing an operation in time series when the actuator is inserted into a solenoid-locked safety switch (fig. 1) which is another example of the safety switch.

Fig. 13 is a time-series diagram showing an operation when the actuator is inserted into the safety switch (fig. 12).

Fig. 14 is a time-series diagram illustrating an operation when the actuator is inserted into the safety switch (fig. 12).

Detailed Description

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

Fig. 1 to 11 are diagrams for explaining a solenoid drive control device according to an embodiment of the present invention. Here, a case where the solenoid drive control device is applied to a spring-lock type safety switch is taken as an example. In fig. 2 and 8 to 10, the cross-sectional area is shown by gray coloring. For convenience of explanation, in the following description, "upper" and "upper" refer to upper parts in fig. 2 and 8 to 10, and "lower", "lower" and "lower" refer to lower parts in the respective drawings, and depending on the method of mounting the safety switch, the upper part is not necessarily limited to the vertical upper part, and similarly, the lower part is not necessarily limited to the vertical lower part.

Fig. 1 is an exploded assembly view of a switch main body constituting a safety switch, and fig. 2 is a view showing a longitudinal section of the switch main body together with an actuator. As shown in fig. 1 and 2, the safety switch 1 includes a switch main body 2 and an actuator 3. The switch main body 2 includes: a main body case 20; a body portion 21 housed in the body case 20 from the opening portion 20a of the body case 20; a head 4 attached to an upper portion of the main body case 20 and having a plurality of actuator insertion ports 4a into which the actuators 3 are inserted and removed; and a bottom cover 5 attached to a lower portion of the main body case 20. The switch body 2 is attached to, for example, a wall or a fixed door (not shown), and the actuator 3 is attached to, for example, a movable door (not shown).

As shown in fig. 1 and 2, the main body 21 includes: a solenoid 22; an operation lever 23; and a contact block 24 having a plurality of contacts for controlling an external device and switching the contacts by movement of the operation lever 23. As shown in fig. 2, the solenoid 22 has: a solenoid body 22A configured by an electromagnetic coil to which power is supplied from an external power supply; a movable iron core (movable portion) 23A provided so as to be capable of being attracted by the solenoid main body 22A and capable of moving in the axial direction so as to be capable of realizing an attraction position attracted by the solenoid main body 22 and a non-attraction position not attracted by the solenoid main body 22A; and a fixed core 22B fixed to a lower portion of the solenoid main body 22A. The operating lever 23 is disposed inside the movable core 23A, and receives an action from the movable core 23A while vertically inserting the movable core 23A. The solenoid body 22A is disposed on the outer periphery of the movable core 23A. The fixed core 22B has a through hole at the center thereof for supporting the operating rod 23 to be movable in the axial direction, and has an inclined surface 22Ba at the upper end thereof.

An inclined surface 23Aa which can be brought into contact with the inclined surface 22Ba at the upper end of the fixed core 22B is formed at the lower end of the movable core 23A. When the movable core 23A moves downward, the inclined surface 23Aa at the lower end of the movable core 23A abuts against the inclined surface 22Ba at the upper end of the fixed core 22B, thereby setting a stop end when the movable core 23A moves downward, and therefore, the fixed core 22B also functions as a stopper when the movable core 23A moves downward. A snap ring (a shaft stopper) 23C is attached to an outer peripheral surface of a central portion of the operating rod 23, and a recess 23Ab that allows the movement of the snap ring 23C when the operating rod 23 moves is formed in an inner peripheral surface of a lower portion of the movable core 23A. When the operation lever 23 moves upward, the snap ring 23C abuts on the upper end of the recess 23Ab of the movable core 23A, thereby setting the stop end when the operation lever 23 moves upward relative to the movable core 23A. The movable iron core 23A and the operating rod 23 are moved to the other axial side in conjunction with the movement of the one axial side by the snap ring 23C.

As shown in fig. 1, the contact block 24 has a plurality of contacts 24a (only a part of which is shown in the figure) that can be switched. As shown in fig. 2, the contact block 24 includes a contact switching block (moving body) 25, and the contact switching block (moving body) 25 is locked to the lower end of the operating lever 23, and is provided to move together with the operating lever 23 and to switch the contacts 24 a. The contact switching block 25 has a rib (detected portion) 25A (see fig. 1) protruding laterally. As shown in fig. 1 and 2, a side plate 26 facing the rib 25A is disposed on a side of the contact switching block 25. The side plate 26 is provided with a terminal block 27 of the solenoid 22 and a photointerrupter (detection unit) 28 for detecting the rib 25A of the contact switching block 25. In fig. 2, the photointerrupter 28 is disposed above the rib 25A.

As shown in fig. 3 to 6, the contact switching block 25 includes: a cylindrical portion 25C disposed at the center; a locking recess 25Cb provided at an upper portion of the cylindrical portion 25C and capable of locking a lower end of the operation lever 23; and a pair of contact switching portions 25B, 25D that extend to both sides of the cylindrical portion 25C and are provided integrally with the cylindrical portion 25C. Inclined surfaces (acting portions) 25B acting on the contacts 24a of the contact block 24 are provided below the contact switching portions 25B and 25D, respectively₁、25B₂、25D₁、25D₂. Further, the rib 25A is provided in one contact switching portion 25B.The rib 25A is a thin plate-like member.

As shown by the one-dot chain line in fig. 5, the photointerrupter 28 for detecting the rib 25A is a transmissive photosensor shaped like コ in plan view, and includes: a light emitting portion 28A having a light emitting element built therein; and a light receiving unit 28B that is disposed to face the light emitting unit 28A with a predetermined gap therebetween and incorporates a light receiving element. Further, the structure is: the light receiving element of the light receiving unit 28B receives the light L emitted from the light emitting element of the light emitting unit 28A, and the rib 25A, which is a detection object, blocks the light L between the light emitting unit 28A and the light receiving unit 28B to detect the rib 25A. Although not shown, the output of the photointerrupter 28 is input to a switching element such as a Field Effect Transistor (FET).

In the present embodiment, the rib 25A is integrally provided on the contact switching block 25, and since the contact switching block 25 is locked to the lower end of the operation lever 23 and moves integrally with the operation lever 23, the detection of the rib 25A is equivalent to the detection of the operation lever 23. Further, as described above, since the operating rod 23 is moved in the axial direction in conjunction with the axial movement of the movable core 23A via the snap ring 23C, the detection of the operating rod 23 is the detection of the state of the movable core 23A. Further, the contact switching block 25 can be said to move by the action from the movable core 23A. As the light emitting element of the light emitting section 28A, for example, an LED (light emitting diode) can be used, and as the light receiving element of the light receiving section 28B, for example, a phototransistor can be used. In a state where the light-shielding material is not present, a current flows through the phototransistor, and in a state where the light-shielding material is present, no current or almost no current flows through the phototransistor, so that the configuration is such that: the position of the rib 25A and thus the operation lever 23 (i.e., the position of the movable core 23A) is detected based on the change in the current on the light receiving portion 28B side.

As shown in fig. 2, a hole 25Ca (fig. 4) formed at the lower end of the cylindrical portion 25C of the contact switching block 25 is disposed below the contact switching block 25, and a tapered shaft portion 29A of a retainer 29 is inserted into the hole 25Ca, and the retainer 29 holds the contact block 24 and is attached to the lower portion of the solenoid 22. A compression coil spring 29S is disposed around the shaft portion 29A. The upper end of the compression coil spring 29S is pressed against the bottom wall surface of the hole 25Ca of the cylindrical portion 25C, and the lower end of the compression coil spring 29S is pressed against the upper surface of the retainer 29. With this structure, the elastic reaction force of the compression coil spring 29S is caused to act upward on the operating lever 23 via the contact switching block 25.

As shown in fig. 2, a cam 40 is provided inside the head 4 of the switch body 2, and the cam 40 is rotatably supported by a central shaft 41. The cam 40 has a plurality of notches 40c, and the cam 40 is rotated by engaging the tip end portion of the actuator 3 inserted from the actuator insertion port 4a of the head 4 into the head 4 with the notches 40c of the cam 40. The movable iron core 23A functions via the operating lever 23 as described later, and locks or unlocks the rotation of the cam 40. In the state shown in fig. 2, the distal end 23a of the operating lever 23 elastically abuts against a recess 40b formed in the lower portion of the cam 40.

Fig. 7 shows a drive control device for the solenoid 22. The drive control device 100 includes: a photo-interrupter 28; and a current control unit 51 for controlling the current supplied to the solenoid 22 in accordance with the detection result of the photo-interrupter 28, wherein the photo-interrupter 28 and the current control unit 51 are connected to an external power supply 50. The current control unit 51 has an analog IC (not shown) that performs 2-stage control of the supply current to the solenoid 22 based on the output from the photointerrupter 28 and performs constant current control.

Next, the drive control of the solenoid 22 by the drive control device 100 will be described with reference to fig. 8 to 11.

Fig. 8 corresponds to a state after the movable door is closed. At this time, the actuator 3 attached to the movable door is inserted into the head 4 of the switch body 2 of the safety switch 1, and the cam 40 is rotated counterclockwise as shown in the drawing. Further, since the power is not supplied from the external power supply 50 (fig. 7) to the solenoid body 22A of the solenoid 22 (the solenoid is in the closed state), the operating lever 23 and the movable core 23A are moved upward by the elastic reaction force of the compression coil spring 29S and are disposed at the non-attracting position, and accordingly, the tip end portion 23A of the operating lever 23 is engaged with the notch 40c of the cam 40, and the cam 40 is brought into the locked state locked in the rotational direction.

In the locked stateEven when the actuator 3 is pulled out from the head 4, the rotation of the cam 40 in the clockwise direction in the figure is restricted by the interference of the notch 40c and the operation lever 23. Further, each inclined surface 25B of the contact switching block 25₁、25B₂、25D₁、25D₂Fig. 3 is a diagram for switching the contacts 24a of the contact block 24 by acting on the contacts 24a (fig. 1), thereby outputting an on signal to the machine inside the door and enabling the machine to be operated. When the operating lever 23 and the movable core 23A are located at the non-attracting position, as shown in the partially enlarged view surrounded by a circle in fig. 8, the rib 25A of the contact switching block 25 shields the light receiving portion 28B of the photo-interrupter 28, and the photo-interrupter 28 detects the rib 25A. At this time, no current or almost no current flows through the light receiving portion 28B of the photo-interrupter 28.

When power is supplied from the external power supply 50 to the solenoid 22 via the current control unit 51 (fig. 7) from this state, the solenoid 22 is turned on. At this time, the current control unit 51 supplies a solenoid current corresponding to the detection result of the photointerrupter 28 to the solenoid main body 22A. As shown in fig. 11, the solenoid current is Imax (drive current), and the solenoid 22 is driven in the full power mode.

Then, as shown in fig. 9, the movable iron core 23A is attracted by the solenoid body 22A and moves downward against the elastic reaction force of the compression coil spring 29S, so that the operating rod 23 receives the action from the movable iron core 23A via the snap ring 23C and moves downward. When the inclined surface 23Aa at the lower end of the movable core 23A abuts against the inclined surface 22Ba at the upper end of the fixed core 22B, the downward movement of the movable core 23A and the operating rod 23 is stopped. The stop position at this time is the suction position of the operating lever 23 and the movable core 23A. At this suction position, the distal end 23a of the operating lever 23 moves to a position away downward from the bottom surface of the cutout 40c of the cam 40, and therefore, the locked state of the cam 40 is released and the cam 40 is brought into the unlocked state. At this time, as shown in the partially enlarged view surrounded by a circle in fig. 9, the rib 25A of the contact switching block 25 moves below the light receiving portion 28B of the photo-interrupter 28, so that the photo-interrupter 28 does not detect the rib 25A, and the light receiving portion 28B receives light from the light emitting portion 28A (fig. 5). At this time, the current flows through the light receiving portion 28B of the photointerrupter 28.

As shown in fig. 11, the current control unit 51 reduces the solenoid current supplied to the solenoid main body 22A from Imax to Ih (< Imax) (holding current) based on the detection result of the photo-interrupter 28. Accordingly, the solenoid 22 is driven in the energy saving mode. In the present embodiment, it is set that the photo-interrupter 28 does not detect the rib 25A, that is, the current flows through the light receiving portion 28B of the photo-interrupter 28, at an intermediate position between the movement of the operating lever 23 and the movable core 23A from the non-attracting position (fig. 8) to the attracting position (fig. 9), more specifically, at a position near the attracting position, but the photo-interrupter 28 may set the non-detection of the rib 25A at a time point when the operating lever 23 and the movable core 23A reach the attracting position (that is, at a position near the attracting position, which is not included).

Next, fig. 10 shows a state in which the actuator 3 is pulled out from the head 4 of the switch body 2 of the safety switch 1 from the state shown in fig. 9, and corresponds to an open state of the movable door. When the actuator 3 is pulled out from the head 4, the actuator 3 rotates the cam 40 in the clockwise direction as shown in the figure, and thereby the operating lever 23 is pushed downward by the rotating cam 40, and the tip 23a of the operating lever 23 elastically abuts against the concave portion 40b at the lower portion of the cam 40. When the operating lever 23 is pushed downward by the cam 40, the operating lever 23 moves downward against the elastic reaction force of the compression coil spring 29S.

In fig. 10, the operation lever 23 is moved downward to move the rib 25A of the contact switching block 25 downward, and the light receiving portion 28B of the photo-interrupter 28 continues to receive light, so that the driving state of the solenoid 22 continues to be maintained in the energy saving mode.

As described above, according to the present embodiment, the current control unit 51 controls the current supplied to the solenoid 22 so that a large solenoid current (drive current) Imax is supplied to the solenoid 22 in a state where the operation lever 23 and the movable core 23A are in the non-attracting position and a small solenoid current (holding current) Ih (< Imax) is supplied to the solenoid 22 in a state where the operation lever 23 and the movable core 23A are in the attracting position or a position near thereto, in accordance with the result of detection of the rib 25A by the photointerrupter 28 (i.e., detection of the operation lever 23 (and thus the movable core 23A)).

Accordingly, when the operating lever 23 and the movable core 23A are in the attraction position or the position near the attraction position, the current supplied to the solenoid 22 can be reduced to reduce the current consumption of the solenoid 22, and as a result, energy can be saved by power saving, and the temperature increase can be reduced, so that the risk of heat such as coil burning can be reduced.

In the present embodiment, when the cam is shifted from the cam unlocked state shown in fig. 9 to the cam locked state shown in fig. 8, the photo-interrupter 28 is set to detect the rib 25A at an intermediate position between the movement of the operating lever 23 and the movable core 23A from the attraction position (fig. 9) to the non-attraction position (fig. 8), more specifically, at a position near the non-attraction position, that is, at a position where no current or almost no current flows through the light receiving portion 28B of the photo-interrupter 28, but the photo-interrupter 28 may detect the rib 25A at a timing when the operating lever 23 and the movable core 23A reach the non-attraction position (that is, at a position near the non-attraction position).

Here, consider the following: unlike the present embodiment, the photo-interrupter 28 is set to detect that the operating lever 23 and the movable core 23A are at the suction position or the position near the suction position during the normal operation (that is, the photo-interrupter 28 is set to detect the rib 25A in the state where the operating lever 23 and the movable core 23A are at the suction position or the position near the suction position). In this case, when the photointerrupter 28 fails (for example, light is not emitted from the light emitting element of the light emitting unit 28A due to deterioration or the like), even if the operation lever 23 and the movable core 23A are at the non-attracting position or the position in the vicinity thereof, it is erroneously detected that the operation lever 23 and the movable core 23A are at the attracting position or the position in the vicinity thereof. Therefore, even in a state where the drive current must be supplied to the solenoid 22 (a state where the operating lever 23 and the movable core 23A are in the non-attracting position and the vicinity thereof), the drive current is not supplied to the solenoid 22 but the holding current smaller than the drive current is supplied. As a result, the movable core 23A is not normally attracted, and the operation lever 23 does not normally operate, and therefore, a locking failure or an unlocking failure occurs.

In contrast, if it is preset that the photointerrupter 28 detects that the operating lever 23 and the movable core 23A are at the non-attracting position or the position in the vicinity thereof during the normal operation as in the present embodiment, when the photointerrupter 28 fails, the operating lever 23 and the movable core 23A are erroneously detected as being at the non-attracting position or the position in the vicinity thereof (that is, as a state in which the drive current must be supplied to the solenoid) regardless of the actual positions of the operating lever 23 and the movable core 23A. Although the detection is false, the detection is always false, because the detection is "a state in which the drive current must be supplied to the solenoid", the drive current is always supplied to the solenoid 22 regardless of the state of the operating lever and the movable core 23A. Accordingly, the basic function of normally operating the operating lever 23 by always attracting the movable core 23A can be ensured, and the occurrence of the locking failure and the unlocking failure is prevented.

Next, fig. 12 to 14 show an example in which the solenoid drive control device according to the present embodiment is applied to a solenoid lock type safety switch. In each of the drawings, the same reference numerals as those in fig. 8 to 10 denote the same or corresponding portions, and the cross-sectional positions are similarly colored in gray. In the following description, "upper" and "upper" refer to the upper side in fig. 12 to 14, and "lower", "lower" and "lower" refer to the lower side in the respective drawings for convenience of description.

As shown in fig. 12 to 14, unlike the spring-lock type safety switch, the solenoid-lock type safety switch is configured such that a fixed iron core 22B is disposed above a solenoid 22 and a movable iron core 23A is disposed below the solenoid 22, and a coil spring 23S is disposed between the fixed iron core 22B and the movable iron core 23A and on the outer periphery of an operating lever 23. The solenoid 22 is attracted in an upward direction opposite to the spring lock type. The snap ring 23C is attached to the outer peripheral surface of the lower portion of the operating rod 23.

Fig. 12 shows a state before the actuator 3 is inserted into the head 4 of the switch body 2 of the safety switch 1, corresponding to an open state of the movable door. At this time, the operating lever 23 is pushed downward by the cam 40, and the tip 23a of the operating lever 23 elastically abuts against the recess 40b in the lower portion of the cam 40. When the operating lever 23 is pushed downward by the cam 40, the operating lever 23 moves downward against the elastic reaction force of the compression coil spring 29S. In this state, the cam 40 is in the unlocked state, the movable core 23A is not attracted by the solenoid body 22A, and the operating lever 23 and the movable core 23A are in the non-attracting position.

At this time, as shown in the partially enlarged view surrounded by a circle in fig. 12, the rib 25A shields the light receiving portion 28B of the photo-interrupter 28, and the photo-interrupter 28 detects the rib 25A, and no current or almost no current flows through the light receiving portion 28B of the photo-interrupter 28.

Fig. 13 shows a state in which the actuator 3 is inserted into the head 4 and the cam 40 is rotated counterclockwise. At this time, the operation lever 23 is moved upward by the elastic reaction force of the compression coil spring 29S, so that the distal end 23a of the operation lever 23 is positioned in the notch 40c of the cam 40, and a gap is formed between the distal end 23a and the bottom surface of the notch 40 c. Further, a snap ring 23C at the lower portion of the operating lever 23 is pressed against the lower end of the movable core 23A from below.

At this time, the cam 40 is in the unlocked state, the movable core 23A is not attracted by the solenoid body 22A, and the operating lever 23 and the movable core 23A are in the non-attracting position. At this time, as shown in the partially enlarged view surrounded by a circle in fig. 13, the rib 25A still shields the light receiving portion 28B of the photo-interrupter 28, and the photo-interrupter 28 detects the rib 25A, and no current or almost no current flows through the light receiving portion 28B of the photo-interrupter 28.

When power is supplied from the external power supply 50 to the solenoid 22 via the current control unit 51 (fig. 7) from this state, the solenoid 22 is turned on. At this time, the current control unit 51 supplies a solenoid current corresponding to the detection result of the photointerrupter 28 to the solenoid main body 22A. As shown in fig. 11, the solenoid current is Imax (drive current), and the solenoid 22 is driven in the full power mode.

Then, as shown in fig. 14, the movable core 23A is attracted by the solenoid body 22A and moves upward against the elastic reaction force of the coil spring 23S, whereby the operating lever 23 moves upward together with the movable core 23A. When the inclined surface 23Aa at the upper end of the movable core 23A abuts against the inclined surface 22Ba at the lower end of the fixed core 22B, the upward movement of the movable core 23A and the operating rod 23 is stopped. The stop position at this time is the suction position of the operating lever 23 and the movable core 23A. In this suction position, the distal end 23a of the operating lever 23 is disposed in a position abutting against or close to the bottom surface of the cutout 40c of the cam 40, and thus the cam 40 is in a locked state. At this time, as shown in the partially enlarged view surrounded by a circle in fig. 14, the rib 25A of the contact switching block 25 moves above the light receiving portion 28B of the photo-interrupter 28, so that the photo-interrupter 28 does not detect the rib 25A, and the light receiving portion 28B receives light from the light emitting portion 28A (fig. 5). At this time, the current flows through the light receiving portion 28B of the photointerrupter 28.

As shown in fig. 11, the current control unit 51 reduces the solenoid current supplied to the solenoid main body 22A from Imax to Ih (< Imax) (holding current) based on the detection result of the photo-interrupter 28. Accordingly, the solenoid 22 is driven in the energy saving mode. In the present embodiment, the photo-interrupter 28 is set to detect the rib 25A, that is, the current is set to flow through the light receiving portion 28B of the photo-interrupter 28, at the intermediate position between the movement of the operating lever 23 and the movable core 23A from the non-attracting position (fig. 13) to the attracting position (fig. 14), more specifically, at the position near the attracting position, but the photo-interrupter 28 may not set the rib 25A at the time when the operating lever 23 and the movable core 23A reach the attracting position (that is, at the position near the attracting position).

As described above, according to the present embodiment, the current control unit 51 controls the current supplied to the solenoid 22 in accordance with the result of the detection of the rib 25A by the photointerrupter 28 (i.e., the detection of the operating lever 23 (and thus the movable core 23A)), so that the solenoid 22 is supplied with the large solenoid current (driving current) Imax in the state where the operating lever 23 and the movable core 23A are at the non-attracting position, and the solenoid 22 is supplied with the small solenoid current (holding current) Ih (< Imax) in the state where the operating lever 23 and the movable core 23A are at the attracting position or the vicinity thereof.

Accordingly, when the operating lever 23 and the movable core 23A are in the attraction position or the position near the attraction position, the current supplied to the solenoid 22 can be reduced to reduce the current consumption of the solenoid 22, and as a result, energy can be saved by saving electricity, and the heat risk such as burning of the coil can be reduced by reducing the temperature increase.

In the present embodiment, when the cam lock state shown in fig. 14 is shifted to the cam unlock state shown in fig. 13, the photo-interrupter 28 is set to detect the rib 25A at an intermediate position between the operation lever 23 and the movable core 23A moving from the attraction position (fig. 14) to the non-attraction position (fig. 13), more specifically, at a position near the non-attraction position, that is, at a position where no current or almost no current flows through the light receiving portion 28B of the photo-interrupter 28, but the photo-interrupter 28 may set the detection of the rib 25A at a timing when the operation lever 23 and the movable core 23A reach the non-attraction position (that is, at a position near the non-attraction position).

Here, consider the following: unlike the present embodiment, the photo-interrupter 28 is set to detect that the operating lever 23 and the movable core 23A are at the suction position or the position near the suction position during the normal operation (that is, the photo-interrupter 28 is set to detect the rib 25A in the state where the operating lever 23 and the movable core 23A are at the suction position or the position near the suction position). In this case, when the photointerrupter 28 fails (for example, light is not emitted from the light emitting element of the light emitting unit 28A due to deterioration or the like), even if the operation lever 23 and the movable core 23A are at the non-attracting position or the position in the vicinity thereof, it is erroneously detected that the operation lever 23 and the movable core 23A are at the attracting position or the position in the vicinity thereof. Therefore, even in a state where the drive current must be supplied to the solenoid 22 (a state where the operating lever 23 and the movable core 23A are in the non-attracting position and the vicinity thereof), the drive current is not supplied to the solenoid 22 but the holding current smaller than the drive current is supplied. As a result, the movable core 23A is not normally attracted, and the operation lever 23 does not normally operate, and therefore, a locking failure or an unlocking failure occurs.

In contrast, if it is preset that the photointerrupter 28 detects that the operating lever 23 and the movable core 23A are at the non-attracting position or the position in the vicinity thereof during the normal operation as in the present embodiment, when the photointerrupter 28 fails, the operating lever 23 and the movable core 23A are erroneously detected as being at the non-attracting position or the position in the vicinity thereof (that is, as a state in which the drive current must be supplied to the solenoid) regardless of the actual positions of the operating lever 23 and the movable core 23A. Although the detection is false, the detection is always false, because the detection is "a state in which the drive current must be supplied to the solenoid", the drive current is always supplied to the solenoid 22 regardless of the state of the operating lever and the movable core 23A. Accordingly, the basic function of normally operating the operating lever 23 by always attracting the movable core 23A can be ensured, and the occurrence of the locking failure and the unlocking failure is prevented.

[ 1 st modification ]

In the above embodiment, the following example is shown: the contact switching block 25 has two functions of switching the contacts 24a of the contact block 24 and detecting the position of the operating lever 23, and can easily perform the two functions in conjunction with each other, and can reduce the number of components to reduce the manufacturing cost. The detected portion may be directly attached to the operation lever 23 and detected by the photo-interrupter 28.

[ 2 nd modification ]

In the above embodiment, the following example is shown: the photo interrupter 28 is used as a detection unit for detecting the rib 25A of the contact switching block 25, but a reed switch, a micro switch, a magnetic switch, or the like may be used instead of the photo interrupter 28.

[ 3 rd modification ]

In the above embodiment, the following example is shown: the supply current to the solenoid 22 is controlled by the analog IC 2-stage control and the constant current control, but the application of the present invention is not limited to this. For example, pulse control may be performed. That is, the current supplied to the solenoid 22 can be controlled by applying a pulse voltage to the solenoid 22 and changing the duty ratio or the period of the pulse width. Alternatively, the input voltage may be reduced by a voltage reduction circuit to control the supply current to the solenoid 22.

[ 4 th modification ]

In the above embodiment, the example in which the operating lever 23 is provided in addition to the movable core 23A is shown, but the application of the present invention is not limited to this. In the present invention, the operating lever 23 may be omitted and the movable core 23A may be extended in the axial direction so that the movable core 23A also functions as the operating lever. In this case, the state of the movable core 23A can be directly detected by the photo-interrupter 28.

[ 5 th modification ]

In the above embodiment, the following example is shown: the photointerrupter 28 detects that the movable core 23A is at the non-attracting position or the position near the non-attracting position by the operating lever 23, but the application of the present invention is not limited to this. The photointerrupter 28 of the present invention can detect that the movable core 23A is at the attraction position or a position near the attraction position by the operating lever 23.

[ 6 th modification ]

In the above embodiment, the following example is shown: the operating lever 23 also functions as a locking member for locking the cam 40, but the application of the present invention is not limited thereto. In the present invention, a lock member that locks the cam 40 may be provided independently of the operating lever 23.

[ 7 th modification ]

In the above-described embodiments, the solenoid applied to the spring-lock type safety switch corresponds to a so-called "pull" solenoid, and the solenoid applied to the solenoid-lock type safety switch corresponds to a so-called "push" solenoid, but the solenoid to which the drive control device according to the present invention is applied can also be applied to: a so-called "self-holding type" solenoid in which the movable iron core is held at the attraction position by the attraction force of the permanent magnet. In this case, the holding current of the solenoid is zero (i.e., Ih ═ 0).

[ 8 th modification ]

In the above embodiment, the following example is shown: the state of the movable core 23A (i.e., the state of the suction position, the non-suction position, or the like) is indirectly detected by detecting the position of the operating lever 23, but the position detection means is not limited to the operating lever 23. Any movable member may be used as long as it is a member connected to the movable core 23A.

[ 9 th modification ]

In the above embodiment, the solenoid in which the movable iron core 23A reciprocates (i.e., moves linearly) in the axial direction is described as an example, but the present invention can also be applied to: a solenoid of a type in which the movable core is tilted (or rotated) about a fulcrum, a type in which the movable core rotates about an axis, or the like. As described above, the drive control device according to the present invention can be applied to: and all the electric components that cause current to flow through the copper wire to generate a magnetic field to attract the movable iron core.

[ other modifications ]

The above-described embodiments and modifications are to be considered in all respects as illustrative only and not restrictive. Even if not explicitly stated in the present specification, it will be apparent to those skilled in the art from the above description that, in consideration of the above teaching, the following may be constructed: various modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains.

[ other application examples ]

The present invention is not limited to the safety switch described above, and can be applied to various apparatuses and devices using a solenoid.

Industrial applicability of the invention

The present invention is useful for a drive control device for a solenoid that achieves energy saving and reduces the thermal risk due to a temperature rise.

Description of the reference numerals

1 … safety switch; 2 … switch body; 3 … actuator; a 40 … cam; 22 … solenoid; 22a … solenoid body; 23a … movable core (movable part); 25 … contact switching block (moving body); 25a … rib (detected part); 25B₁、25B₂、25D₁、25D₂… inclined plane (acting part); 28 … photointerrupter (detection unit); 51 … current control part; 100 … drive control means; imax … drive current (current 1); ih … holds the current (current 2).