Solenoid drive control device and safety switch having the same

Abstract

Energy saving can be achieved and the thermal risk caused by temperature rise can be reduced. The solenoid drive control device 100 is configured as follows: a solenoid body 22A that attracts a movable iron core 23A, and the solenoid body 22A supports the movable iron core 23A so that the movable iron core 23A can achieve an attraction position where the movable iron core 23A is attracted by the solenoid body 22A and a non-attraction position where the movable iron core 23A is not attracted by the solenoid body 22A. A photo interrupter 28 is provided, which detects the state of the movable iron core 23A; and a current control unit 51 is provided, which controls the supply current to the solenoid body 22A according to the detection result of the photo interrupter 28, so that the drive current Imax is supplied to the solenoid body 22A when the movable iron core 23A is in the non-attraction position or a position near it, and the holding current Ih less than the drive current Imax is supplied to the solenoid body 22A when the movable iron core 23A is in the attraction position or a position near it.

Description

Technical Field

[0001] The present invention relates to a solenoid drive control device for achieving energy saving and reducing thermal risk caused by temperature increase, and a safety switch having the drive control device. Background Art

[0002] Generally, a solenoid includes a solenoid body having an electromagnetic coil and a movable part slidably supported on the solenoid body. When the electromagnetic coil is energized, the electromagnetic coil generates a magnetic field passing through the movable part, and the movable part is attracted to the solenoid body by the magnetic force.

[0003] Here, the magnetic force is inversely proportional to the square of the distance, so in the solenoid, a larger current (driving current) is required when the movable part is attracted. However, after the movable part is attracted, the movable part enters the magnetic field and the same current is not required, and a smaller current (holding current) is sufficient.

[0004] However, in the conventional solenoid, even when the movable part is held after attraction, the same current as during attraction continues to flow, thereby increasing power consumption, or causing adverse effects on surrounding equipment due to heat generation of the solenoid, or causing harm to the human body due to heat generation of the outer cover of the solenoid when installed in a place where people are close. In addition, there is a risk of burning of the electromagnetic coil.

[0005] Therefore, in the solenoid power control method described in Japanese Patent Application Laid-Open No. 2000-173822, when the power switch for the coil is turned on, the full current is supplied to the coil, and after a predetermined time has passed since the start of power supply, the current supplied to the coil is maintained at a relatively small value by a current limiting circuit (see paragraphs

[0046] to

[0048] of the publication). The publication states that: With such a structure, the solenoid can save power, reduce heat generation, and prevent the coil from burning out.

[0006] On the other hand, a safety switch is known as a device using a solenoid. The safety switch is a switch that is provided at the entrance and exit of a dangerous area where a machine tool or the like is arranged, is turned on / off in accordance with the opening and closing state of the door, and includes: an actuator mounted on the door side; and a switch body mounted on the wall side and into which the actuator is plugged in and out. The switch body includes: a cam that can rotate due to the insertion of the actuator; an operating rod that can move in the axial direction, and one end of which is configured to be able to abut against the cam and the other end of which is configured to be able to switch the contacts; and a solenoid that is arranged around the operating rod. When the movable door is opened and closed, the actuator that moves with the movable door is plugged in and out relative to the switch body, so that the cam inside the switch body rotates, and the operating rod moves in the axial direction in accordance with the rotational position of the cam, and accordingly, the on / off of the contacts is switched and an on / off signal is sent to the machine tool. The solenoid of the safety switch is provided for the purpose of switching the locking / unlocking of the cam by attracting and moving the operating rod when the movable door is opened or closed.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2000-173822 (see paragraphs

[0046] to

[0048] ) Summary of the invention

[0010] In the past, for the energization control of the solenoid of such a safety switch, even when the operating rod is attracted and the attracted state of the operating rod is maintained, the same current as when the operating rod is attracted continues to flow, so there are also the above-mentioned problems of increased power consumption and thermal risks caused by coil heating. Therefore, the following scheme is also considered: adopting the method described in the above-mentioned bulletin, after a constant time has passed after the current is supplied to the solenoid, the larger current (driving current) when the current is supplied is switched to a smaller current (holding current) after the current is supplied.

[0011] However, in the case of a safety switch, if the suction action of the operating rod is not completed until the above-mentioned constant time has passed, the safety switch may be poorly locked or unlocked. Therefore, it can be said that time-based power control is not suitable for a solenoid that operates a device such as a safety switch.

[0012] The present invention is made in view of the above existing situation, and the problem to be solved by the present invention is to provide a solenoid drive control device that can achieve energy saving and reduce the thermal risk caused by temperature increase. In addition, the problem of the present invention is to provide a solenoid drive control device that can reliably lock and unlock the safety switch.

[0013] The present invention relates to a solenoid drive control device, which has a solenoid body for attracting a movable part, and the solenoid body supports the movable part so that the movable part can achieve an attraction position where the movable part is attracted by the solenoid body and a non-attraction position where the movable part is not attracted by the solenoid body. The device includes: a detection unit that detects the state of the movable part; and a current control unit that controls the supply current to the solenoid body according to the detection result of the detection unit, so that a first current is supplied to the solenoid body when the movable part is in the non-attraction position or a position near it, and a second current that is smaller than the first current is supplied to the solenoid body when the movable part is in the attraction position or a position near it.

[0014] According to the present invention, the movable part moves to the attraction position when being attracted by the solenoid body, and moves to the non-attraction position when not being attracted by the solenoid body. At this time, the state of the movable part is detected by the detection unit. Moreover, the current control unit controls the supply current to the solenoid body in accordance with the detection result of the detection unit, so that when the movable part is in the non-attraction position or a position near it, the first current is supplied to the solenoid body, and when the movable part is in the attraction position or a position near it, the second current smaller than the first current is supplied to the solenoid body.

[0015] Accordingly, when the movable part is in the attraction position or a position near it, the current supplied to the solenoid body is reduced, thereby reducing the current consumption of the solenoid. Energy saving can be achieved by saving electricity, and the temperature rise can be weakened, thereby reducing thermal risks such as burning of the coil.

[0016] In the present invention, the movable part is provided with a moving body that moves in response to an action from the movable part, and the moving body is provided with an acting part that applies an action to a contact for controlling an external device and a detected part that is detected by the detecting part.

[0017] In the present invention, the detection unit is used to detect that the movable part is in the non-attraction position or a position near it, and when the detection unit fails, the first current is supplied to the solenoid body by the current control unit.

[0018] The present invention relates to a safety switch, which is equipped with the above-mentioned drive control device and comprises: a switch body having contacts; an actuator that is inserted and removed relative to the switch body; and a cam that can rotate by inserting the actuator, and the movable part of the solenoid acts to lock or unlock the rotation of the cam.

[0019] In the present invention, the movable portion includes a moving body that moves when acted upon by the movable portion, and the moving body includes an acting portion that acts on a contact of the switch body and a detected portion that is detected by the detecting portion.

[0020] As described above, according to the present invention, when the movable part is in the attraction position or a position near it, the current supplied to the solenoid body is reduced so that the current consumption of the solenoid is reduced. Accordingly, energy saving brought about by power saving can be achieved, and the temperature rise can be reduced, thereby reducing the thermal risks such as burning of the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an exploded assembly view of a switch body of a safety switch to which a solenoid drive control device according to an embodiment of the present invention is applied.

[0022] Figure 2 is used as the safety switch ( Figure 1 ) is a longitudinal sectional view of a switch body of an example of a spring lock type safety switch.

[0023] Figure 3 The switch body is viewed from above ( Figure 1 ) is a three-dimensional diagram of a contact switching block (moving body).

[0024] Figure 4 The contact switching block is viewed from below ( Figure 3 ) in a stereogram.

[0025] Figure 5 is the contact switching block ( Figure 3 ) above view.

[0026] Figure 6 is the contact switching block ( Figure 3 )’s main view.

[0027] Figure 7 The drive control device ( Figure 1 ) is a schematic structural block diagram of the .

[0028] Figure 8 is a time series representation of the safety switch ( Figure 2 ) is a diagram showing the action when the actuator is disengaged.

[0029] Fig. 9 is a time series representation of the safety switch ( Figure 2 ) is a diagram showing the action when the actuator is disengaged.

[0030] Fig.10 is a time series representation of the safety switch ( Figure 2 ) is a diagram showing the action when the actuator is disengaged.

[0031] Fig.11 It means that the drive control device ( Figure 7 ) is a graph showing the change in solenoid current controlled by the actuator.

[0032] Fig.12 is expressed in time series as the safety switch ( Figure 1 ) is a diagram showing the action when an actuator is inserted into another example of a solenoid locking safety switch.

[0033] Fig.13 is expressed in time series in the safety switch ( Fig.12 ) is a diagram showing the action when the actuator is inserted.

[0034] Fig.14 is expressed in time series in the safety switch ( Fig.12 ) is a diagram showing the action when the actuator is inserted. DETAILED DESCRIPTION

[0035] Hereinafter, one embodiment of the present invention will be described based on the drawings.

[0036] Figures 1 to 11 1 is a diagram for explaining a solenoid drive control device according to an embodiment of the present invention. Here, the solenoid drive control device is applied to a spring-locked safety switch as an example. Figure 2 , Figure 8 to Figure 10 In the figure, the cross-sectional area is shown by gray coloring. In addition, for the sake of convenience, in the following description, "above", "upper side" and "upper" refer to Figure 2 , Figure 8 to Figure 10 The above, “below”, “lower side” and “lower” refer to the below in each figure. Depending on the installation method of the safety switch, the above is not necessarily limited to referring to the vertical above, and similarly, the below is not necessarily limited to referring to the vertical below.

[0037] Figure 1 This is an exploded assembly diagram of the switch body that constitutes the safety switch. Figure 2 FIG. 2 is a diagram showing a longitudinal section of the switch body together with the actuator. Figure 1 and Figure 2 As shown, the safety switch 1 includes a switch body 2 and an actuator 3. The switch body 2 includes: a main body housing 20; a main body portion 21, which is received in the main body housing 20 through an opening portion 20a of the main body housing 20; a head portion 4, which is mounted on the upper portion of the main body housing 20 and has a plurality of actuator insertion ports 4a for inserting and removing the actuator 3; and a bottom cover 5, which is mounted on the lower portion of the main body housing 20. The switch body 2 is mounted on, for example, a wall or a fixed door (not shown), and the actuator 3 is mounted on, for example, a movable door (not shown).

[0038] like Figure 1 and Figure 2 As shown, the main body 21 has: a solenoid 22; an operating rod 23; and a contact block 24, which has a plurality of contacts for controlling external devices, and the contacts are switched by the movement of the operating rod 23. Figure 2 As shown, the solenoid 22 has: a solenoid body 22A, which is composed of an electromagnetic coil powered from an external power source; a movable iron core (movable part) 23A, which is configured to be attracted by the solenoid body 22A and to be movable in the axial direction so as to achieve an attracted position attracted by the solenoid body 22 and a non-attracted position not attracted by the solenoid body 22A; and a fixed iron core 22B, which is fixed to the lower part of the solenoid body 22A. The operating rod 23 is arranged on the inner side of the movable iron core 23A, inserts the movable iron core 23A up and down, and is acted upon by the movable iron core 23A. The solenoid body 22A is arranged on the outer periphery of the movable iron core 23A. The fixed iron core 22B has a through hole in the center that supports the operating rod 23 to be movable in the axial direction, and has an inclined surface 22Ba at the upper end.

[0039] The lower end of the movable core 23A is formed with an inclined surface 23Aa that can abut against the inclined surface 22Ba at the upper end of the fixed core 22B. 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 the stop end when the movable core 23A moves downward, so that the fixed core 22B also functions as a stopper when the movable core 23A moves downward. In addition, a retaining ring (shaft retaining ring) 23C is installed on the outer peripheral surface of the central part of the operating rod 23, and a recessed portion 23Ab is formed on the inner peripheral surface of the lower part of the movable core 23A to allow the retaining ring 23C to move when the operating rod 23 moves. When the operating rod 23 moves upward, the retaining ring 23C contacts the upper end of the recess 23Ab of the movable iron core 23A, thereby setting the stop end of the operating rod 23 when it moves upward relative to the movable iron core 23A. In addition, the movable iron core 23A and the operating rod 23 move to the other side of the axial direction in conjunction with the movement on one side of the axial direction by means of the retaining ring 23C.

[0040] like Figure 1 As shown in FIG. 1 , the contact block 24 has a plurality of contacts 24a (only a portion of which is shown in the figure) that can be switched. Figure 2 As shown, the contact block 24 has a contact switching block (moving body) 25, which is fixed to the lower end of the operating rod 23, is set to move together with the operating rod 23 and is used to switch each contact 24a. The contact switching block 25 has a rib (detected portion) 25A extending to the side (see Figure 1 ).like Figure 1 and Figure 2 As shown in FIG. 1 , a side plate 26 is disposed on the side of the contact switching block 25 and faces the rib 25A. The side plate 26 is provided with a terminal block 27 for the solenoid 22 and a photointerrupter (detection unit) 28 for detecting the rib 25A of the contact switching block 25. Figure 2In FIG. 2 , the photointerrupter 28 is disposed above the rib 25A.

[0041] like Figure 3 to Figure 6 As shown, the contact switching block 25 has: a cylindrical portion 25C, which is arranged in the center; a locking recess 25Cb, which is provided at the upper part of the cylindrical portion 25C and can be used to lock the lower end of the operating rod 23; and a pair of contact switching portions 25B, 25D, which extend to both sides of the cylindrical portion 25C and are integrally provided with the cylindrical portion 25C. Inclined surfaces (action portions) 25B1, 25B2, 25D1, 25D2 for applying action to each contact 24a of the contact block 24 are provided at the lower part of each contact switching portion 25B, 25D, respectively. In addition, the above-mentioned rib 25A is provided on one contact switching portion 25B. The rib 25A is a thin plate-shaped component.

[0042] like Figure 5 As shown by the single-dot chain line in , the photointerrupter 28 for detecting the rib 25A is a transmissive optical sensor in a U-shape when viewed from above, and includes: a light-emitting portion 28A having a light-emitting element built therein; and a light-receiving portion 28B having a light-receiving element built therein, which is arranged opposite to the light-emitting portion 28A at a predetermined interval. Moreover, the light-receiving element of the light-receiving portion 28B receives the light L emitted from the light-emitting element of the light-emitting portion 28A, and the rib 25A, which is the detection object, blocks the light L between the light-emitting portion 28A and the light-receiving portion 28B, so as to detect the rib 25A. In addition, although not shown in the figure, the output of the photointerrupter 28 is input to a switching element such as a field effect transistor (FET: Field Effect Transistor).

[0043] In this embodiment, the rib 25A is integrally provided on the contact switching block 25. Since the contact switching block 25 is clamped at the lower end of the operating rod 23 and moves integrally with the operating rod 23, the detection of the rib 25A is equivalent to the detection of the operating rod 23. In addition, as described above, the operating rod 23 moves axially in conjunction with the axial movement of the movable iron core 23A by means of the retaining ring 23C, so the detection of the operating rod 23 is the detection of the state of the movable iron core 23A. In addition, it can also be said that the contact switching block 25 moves due to the action from the movable iron core 23A. As the light emitting element of the light emitting part 28A, for example, an LED (light emitting diode) can be used, and as the light receiving element of the light receiving part 28B, for example, a phototransistor can be used. In the state where there is no light blocking object, current flows in the phototransistor, and in the state where there is a light blocking object, no current or almost no current flows in the phototransistor, so it is configured to detect the position of the rib 25A and thus the operating rod 23 (that is, the position of the movable iron core 23A) according to the change of the current on the side of the light receiving part 28B.

[0044] like Figure 2As shown, a hole 25Ca ( Figure 4 ) is arranged below the contact switching block 25, and the tapered shaft portion 29A of the retainer 29 is inserted into the hole 25Ca, and the retainer 29 retains the contact block 24 and is installed at the lower part of the solenoid 22. A compression coil spring 29S is arranged 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 acts on the operating rod 23 upward via the contact switching block 25.

[0045] like Figure 2 As shown, a cam 40 is provided inside the head 4 of the switch body 2, and the cam 40 is rotatably supported on a central shaft 41. A plurality of notches 40c are formed in the cam 40, and the top end of the actuator 3 inserted into the head 4 from the actuator insertion port 4a of the head 4 engages with the notch 40c of the cam 40 to rotate the cam 40. The movable iron core 23A functions with the aid of the operating lever 23 as described later, so that the rotation of the cam 40 is locked or unlocked. Figure 2 In the illustrated state, the tip 23 a of the operating lever 23 elastically abuts against a recess 40 b formed at the lower portion of the cam 40 .

[0046] Figure 7 1 shows a drive control device for the solenoid 22. The drive control device 100 includes: a photointerrupter 28; and a current control unit 51, which controls the current supplied to the solenoid 22 according to the detection result of the photointerrupter 28, and an external power supply 50 is connected to the photointerrupter 28 and the current control unit 51. The current control unit 51 includes an analog IC (not shown), which performs two-level control of the supply current to the solenoid 22 based on the output from the photointerrupter 28, and performs constant current control.

[0047] Next, use Figure 8 to Figure 11 The drive control of the solenoid 22 by the drive control device 100 will be described.

[0048] Figure 8 This corresponds to the state after the movable door is closed. At this time, the actuator 3 installed on the movable door is inserted into the head 4 of the switch body 2 of the safety switch 1, so that the cam 40 rotates in the counterclockwise direction shown in the figure. In addition, no power is supplied from the external power supply 50 ( Figure 7) supplies power to the solenoid body 22A of the solenoid 22 (solenoid closed state), whereby the operating rod 23 and the movable iron core 23A move upward with the aid of the elastic reaction force of the compression coil spring 29S and are arranged in the non-attraction position, whereby the top end 23a of the operating rod 23 engages in the cutout 40c of the cam 40, so that the cam 40 is formed into a locked state in the rotational direction.

[0049] In this locked state, even if the actuator 3 is pulled out from the head 4, the rotation of the cam 40 in the clockwise direction shown in the figure is restricted by the interference between the cutout 40c and the operating rod 23. Figure 3 ) for each contact 24a of the contact block 24 ( Figure 1 ) is applied to switch each contact 24a, thereby outputting a connection signal to the mechanical output inside the door, so that the mechanical can be operated. In addition, when the operating rod 23 and the movable iron core 23A are in the non-attracting position, as shown in FIG. Figure 8 As shown in the partially enlarged view surrounded by a circle in FIG. 2 , the rib 25A of the contact switching block 25 shields the light receiving portion 28B of the photointerrupter 28, and the photointerrupter 28 detects the rib 25A. At this time, no current or almost no current flows in the light receiving portion 28B of the photointerrupter 28.

[0050] If the current from the external power supply 50 is supplied via the current control unit 51 ( Figure 7 ) and power is supplied to the solenoid 22, so that the solenoid 22 is turned on. At this time, the current control unit 51 supplies the solenoid current corresponding to the detection result of the photointerrupter 28 to the solenoid body 22A. Fig.11 As shown, the solenoid current is Imax (drive current), and the solenoid 22 is driven in full power mode.

[0051] So, if Fig. 9 As shown, 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, thereby causing the operating rod 23 to move downward under the action of the movable iron core 23A with the help of the retaining ring 23C. Moreover, if the inclined surface 23Aa at the lower end of the movable iron core 23A abuts against the inclined surface 22Ba at the upper end of the fixed iron core 22B, the downward movement of the movable iron core 23A and the operating rod 23 stops. The stop position at this time is the attraction position of the operating rod 23 and the movable iron core 23A. At this attraction position, the top end 23a of the operating rod 23 moves toward a position away from the bottom surface of the cutout 40c of the cam 40 downward, thereby releasing the locked state of the cam 40 and causing the cam 40 to be in an unlocked state. In addition, at this time, as Fig. 9As shown in the partially enlarged view surrounded by a circle in FIG. 1 , 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 the light from the light emitting portion 28A ( Figure 5 At this time, current flows in the light receiving portion 28B of the photointerrupter 28.

[0052] like Fig.11 As shown, the current control unit 51 reduces the solenoid current supplied to the solenoid body 22A from Imax to Ih (<Imax) (maintaining the current) based on the detection result of the photo interrupter 28. Accordingly, the solenoid 22 is driven in the energy-saving mode. In addition, in the present embodiment, when the operating rod 23 and the movable iron core 23A are moved from the non-attracting position ( Figure 8 ) moves to the attraction position ( Fig. 9 ), more specifically, at a position near the attraction position, the photo interrupter 28 is set to not detect the rib 25A, that is, the current is set to flow in the light receiving portion 28B of the photo interrupter 28. However, the setting of the photo interrupter 28 not detecting the rib 25A can be performed at the moment when the operating rod 23 and the movable iron core 23A reach the attraction position (that is, excluding the position near the attraction position).

[0053] Next, Fig.10 Indicates Fig. 9 The state shown is a state where the actuator 3 is pulled out from the head 4 of the switch body 2 of the safety switch 1, and corresponds to the 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 shown in the figure, thereby pressing the operating rod 23 downward by the rotating cam 40, and the top end 23a of the operating rod 23 elastically abuts against the concave portion 40b at the bottom of the cam 40. When the operating rod 23 is pressed downward by the cam 40, the operating rod 23 overcomes the elastic reaction force of the compression coil spring 29S and moves downward.

[0054] exist Fig.10 In this case, the operating rod 23 moves downward, causing the rib 25A of the contact switching block 25 to also move downward, so that the light receiving portion 28B of the photointerrupter 28 continues to receive light, and thus the driving state of the solenoid 22 continues to maintain the energy saving mode.

[0055] Thus, 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 rod 23 (and thus the movable iron core 23A)), so that when the operating rod 23 and the movable iron core 23A are in the non-attracted position, a larger solenoid current (driving current) Imax is supplied to the solenoid 22, and when the operating rod 23 and the movable iron core 23A are in the attracted position or a position near the attracted position, a smaller solenoid current (holding current) Ih (<Imax) is supplied to the solenoid 22.

[0056] Accordingly, when the operating rod 23 and the movable iron core 23A are in the attraction position or a position near it, the current supplied to the solenoid 22 can be reduced so that the current consumption of the solenoid 22 is reduced. As a result, energy saving can be achieved by saving electricity, and the temperature increase can be weakened, thereby reducing thermal risks such as coil burning.

[0057] In addition, in this embodiment, when Fig. 9 The cam unlocked state shown is Figure 8 When the cam lock state shown in FIG. 1 is transferred, the operating rod 23 and the movable iron core 23A are moved from the attraction position ( Fig. 9 ) moves to the non-attracting position ( Figure 8 ), more specifically, at a position near the non-attraction position, the photointerrupter 28 is set to detect the rib 25A, that is, it is set so that no current or almost no current flows in the light receiving portion 28B of the photointerrupter 28. However, the setting of the photointerrupter 28 detecting the rib 25A can be performed at the moment when the operating rod 23 and the movable iron core 23A reach the non-attraction position (that is, excluding the position near the non-attraction position).

[0058] Here, the following case is considered: unlike the present embodiment, the photointerrupter 28 is set to detect the state that the operating rod 23 and the movable iron core 23A are in the attraction position or the vicinity thereof during normal operation (that is, the photointerrupter 28 is set to detect the rib 25A when they are in the attraction position or the vicinity thereof). In this case, when the photointerrupter 28 fails (for example, light is not emitted from the light emitting element of the light emitting portion 28A due to degradation, etc.), even if the operating rod 23 and the movable iron core 23A are in the non-attraction position or the vicinity thereof, it is erroneously detected that the operating rod 23 and the movable iron core 23A are in the attraction position or the vicinity thereof. Therefore, even if the state in which the driving current must be supplied to the solenoid 22 is formed (the state in which the operating rod 23 and the movable iron core 23A are in the non-attraction position or the vicinity thereof), the driving current is not supplied to the solenoid 22, but a holding current smaller than the driving current is supplied. As a result, the movable iron core 23A is not attracted normally, and the operating rod 23 does not operate normally, so that a locking failure or an unlocking failure occurs.

[0059] On the other hand, if the photointerrupter 28 is set in advance to detect the situation that the operating rod 23 and the movable iron core 23A are in the non-attracted position or the position near it during normal operation as in the present embodiment, then when the photointerrupter 28 fails, regardless of the actual position of the operating rod 23 and the movable iron core 23A, it will be erroneously detected that the operating rod 23 and the movable iron core 23A are in the non-attracted position or the position near it (that is, the state where the driving current must be supplied to the solenoid). Although it is a false detection, it is always erroneously detected as "the state where the driving current must be supplied to the solenoid", so that the driving current is always supplied to the solenoid 22 regardless of the state of the operating rod and the movable iron core 23A. According to this, the basic function of always attracting the movable iron core 23A so that the operating rod 23 can be normally operated can be ensured, and there will be no locking or unlocking failure.

[0060] Next, Figure 12 to Figure 14 1 and 2 show an example of the solenoid drive control device according to the present embodiment being applied to a solenoid locking safety switch. Figure 8 to Figure 10 The same reference numerals denote the same or corresponding parts, and similarly, gray is used to indicate the cross-sectional position. Figure 12 to Figure 14 The terms “above”, “below”, “lower side” and “lower” refer to the lower side in each drawing.

[0061] like Figure 12 to Figure 14 As shown in the figure, the solenoid lock type safety switch is different from the above-mentioned spring lock type safety switch. The fixed iron core 22B is arranged on the upper part of the solenoid 22, and the movable iron core 23A is arranged below it. A coil spring 23S is arranged between the fixed iron core 22B and the movable iron core 23A and on the outer periphery of the operating rod 23. The suction direction of the solenoid 22 is opposite to the spring lock type, which is upward. In addition, a snap ring 23C is installed on the outer peripheral surface of the lower part of the operating rod 23.

[0062] Fig.12 The state before the actuator 3 is inserted into the head 4 of the switch body 2 of the safety switch 1 corresponds to the open state of the movable door. At this time, the operating rod 23 is pressed downward by the cam 40, and the top 23a of the operating rod 23 elastically abuts against the concave portion 40b at the bottom of the cam 40. When the operating rod 23 is pressed downward by the cam 40, the operating rod 23 overcomes the elastic reaction force of the compression coil spring 29S and moves downward. In this state, the cam 40 is in an unlocked state, the movable iron core 23A is not attracted by the solenoid body 22A, and the operating rod 23 and the movable iron core 23A are in a non-attracting position.

[0063] At this time, if Fig.12As shown in the partially enlarged view surrounded by a circle in FIG. 1 , the rib 25A shields the light receiving portion 28B of the photointerrupter 28 , and the photointerrupter 28 detects the rib 25A. No current or almost no current flows in the light receiving portion 28B of the photointerrupter 28 .

[0064] Fig.13 The figure shows a state where the actuator 3 is inserted into the head 4 and the cam 40 is rotated counterclockwise. At this time, the operating rod 23 is moved upward by the elastic reaction force of the compression coil spring 29S, so that the top end 23a of the operating rod 23 is located in the cutout 40c of the cam 40, and a gap is formed between the top end 23a and the bottom surface of the cutout 40c. In addition, the snap ring 23C at the bottom of the operating rod 23 is pressed against the lower end of the movable iron core 23A from below.

[0065] At this time, the cam 40 is in the unlocked state, the movable iron core 23A is not attracted by the solenoid body 22A, and the operating rod 23 and the movable iron core 23A are in the non-attracting position. Fig.13 As shown in the partially enlarged view surrounded by a circle in FIG. 1 , the rib 25A still shields the light receiving portion 28B of the photointerrupter 28 , and the photointerrupter 28 detects the rib 25A. No current or almost no current flows in the light receiving portion 28B of the photointerrupter 28 .

[0066] If the current from the external power supply 50 is supplied via the current control unit 51 ( Figure 7 ) and power is supplied to the solenoid 22, so that the solenoid 22 is turned on. At this time, the current control unit 51 supplies the solenoid current corresponding to the detection result of the photointerrupter 28 to the solenoid body 22A. Fig.11 As shown, the solenoid current is Imax (drive current), and the solenoid 22 is driven in full power mode.

[0067] So, if Fig.14 As shown, the movable iron core 23A is attracted by the solenoid body 22A and moves upward to overcome the elastic reaction force of the coil spring 23S, thereby causing the operating rod 23 to move upward together with the movable iron core 23A. Moreover, if the inclined surface 23Aa at the upper end of the movable iron core 23A abuts against the inclined surface 22Ba at the lower end of the fixed iron core 22B, the upward movement of the movable iron core 23A and the operating rod 23 stops. The stop position at this time is the attraction position of the operating rod 23 and the movable iron core 23A. At this attraction position, the top end 23a of the operating rod 23 is arranged at a position that abuts or is close to the bottom surface of the cutout 40c of the cam 40, and therefore, the cam 40 is in a locked state. In addition, at this time, as Fig.14As shown in the partially enlarged view surrounded by a circle in FIG. 1 , the rib 25A of the contact switching block 25 moves upward toward 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 the light from the light emitting portion 28A ( Figure 5 At this time, current flows in the light receiving portion 28B of the photointerrupter 28.

[0068] like Fig.11 As shown, the current control unit 51 reduces the solenoid current supplied to the solenoid body 22A from Imax to Ih (<Imax) (maintaining the current) based on the detection result of the photointerrupter 28. Accordingly, the solenoid 22 is driven in the energy-saving mode. In addition, in the present embodiment, when the operating rod 23 and the movable iron core 23A are moved from the non-attracting position ( Fig.13 ) moves to the attraction position ( Fig.14 ), more specifically, at a position near the attraction position, the photo interrupter 28 is set to detect the rib 25A, that is, the current is set to flow in the light receiving portion 28B of the photo interrupter 28. However, the setting of the photo interrupter 28 not to detect the rib 25A can be performed at the moment when the operating rod 23 and the movable iron core 23A reach the attraction position (that is, excluding the position near the attraction position).

[0069] Thus, 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 rod 23 (and thus the movable iron core 23A)), so that a larger solenoid current (driving current) Imax is supplied to the solenoid 22 when the operating rod 23 and the movable iron core 23A are in the non-attracted position, and a smaller solenoid current (holding current) Ih (<Imax) is supplied to the solenoid 22 when the operating rod 23 and the movable iron core 23A are in the attracted position or a position near the attracted position.

[0070] Accordingly, when the operating rod 23 and the movable iron core 23A are in the attraction position or a position near the attraction position, the current supplied to the solenoid 22 can be reduced so that the current consumption of the solenoid 22 is reduced. As a result, energy saving can be achieved by saving electricity, and the temperature increase can be weakened and thermal risks such as burning of the coil can be reduced.

[0071] In addition, in this embodiment, when Fig.14 The cam lock state shown is Fig.13 When the cam unlocking state shown in FIG. 1 is transferred, the operating rod 23 and the movable iron core 23A are moved from the attraction position ( Fig.14 ) moves to the non-attracting position ( Fig.13), more specifically, at a position near the non-attraction position, the photointerrupter 28 is also set to detect the rib 25A, that is, it is set so that no current or almost no current flows in the light receiving portion 28B of the photointerrupter 28. However, the photointerrupter 28 can be set to detect the rib 25A at the moment when the operating rod 23 and the movable iron core 23A reach the non-attraction position (that is, excluding the position near the non-attraction position).

[0072] Here, the following case is considered: unlike the present embodiment, the photointerrupter 28 is set to detect the state that the operating rod 23 and the movable iron core 23A are in the attraction position or the vicinity thereof during normal operation (that is, the photointerrupter 28 is set to detect the rib 25A when they are in the attraction position or the vicinity thereof). In this case, when the photointerrupter 28 fails (for example, the light emitting element of the light emitting unit 28A does not emit light due to degradation, etc.), even if the operating rod 23 and the movable iron core 23A are in the non-attraction position or the vicinity thereof, it is erroneously detected that the operating rod 23 and the movable iron core 23A are in the attraction position or the vicinity thereof. Therefore, even if the state in which the driving current must be supplied to the solenoid 22 is formed (the state in which the operating rod 23 and the movable iron core 23A are in the non-attraction position or the vicinity thereof), the driving current is not supplied to the solenoid 22, but a holding current smaller than the driving current is supplied. As a result, the movable iron core 23A is not attracted normally, and the operating rod 23 does not operate normally, so that a locking failure or an unlocking failure occurs.

[0073] On the other hand, if the photointerrupter 28 is set in advance to detect the situation that the operating rod 23 and the movable iron core 23A are in the non-attracted position or the position near it during normal operation as in the present embodiment, then when the photointerrupter 28 fails, regardless of the actual position of the operating rod 23 and the movable iron core 23A, it will be erroneously detected that the operating rod 23 and the movable iron core 23A are in the non-attracted position or the position near it (that is, the state where the driving current must be supplied to the solenoid). Although it is a false detection, it is always erroneously detected as "the state where the driving current must be supplied to the solenoid", so that the driving current is always supplied to the solenoid 22 regardless of the state of the operating rod and the movable iron core 23A. According to this, the basic function of always attracting the movable iron core 23A so that the operating rod 23 can be normally operated can be ensured, and there will be no locking or unlocking failure.

[0074] [First variant]

[0075] In the above embodiment, the following example is shown: the contact switching block 25 has two functions: switching the contact 24a of the contact block 24 and detecting the position of the operating rod 23, so that the two functions can be easily linked, and the number of components can be reduced to reduce the manufacturing cost, but the application of the present invention is not limited to this. The detected part can be directly mounted on the operating rod 23 and the detected part can be detected by the photointerrupter 28.

[0076] [Second variant]

[0077] In the above embodiment, the photointerrupter 28 is used as the detection unit for detecting the rib 25A of the contact switching block 25 . However, a reed switch, a micro switch, a magnetic switch, or the like may be used instead of the photointerrupter 28 .

[0078] [Third Modification]

[0079] In the above embodiment, the following example is shown: the supply current to the solenoid 22 is controlled by two-level control and constant current control of the analog IC, but the application of the present invention is not limited to this. For example, pulse control can be performed. That is, a pulse voltage can be applied to the solenoid 22 and the duty ratio and period of the pulse width can be changed to control the supply current to the solenoid 22. Alternatively, the supply current to the solenoid 22 can be controlled by reducing the input voltage using a step-down circuit.

[0080] [Fourth Modification]

[0081] In the above embodiment, an example is shown in which the operating rod 23 is provided in addition to the movable iron core 23A, but the application of the present invention is not limited to this. In the present invention, the operating rod 23 can be omitted and the movable iron core 23A can be extended in the axial direction so that the movable iron core 23A also functions as the operating rod. In this case, the state of the movable iron core 23A can be directly detected by the photointerrupter 28.

[0082] [Fifth Modification]

[0083] In the above embodiment, the photointerrupter 28 detects the situation that the movable iron core 23A is in the non-attracting position or in the vicinity thereof by means of the operating rod 23, but the application of the present invention is not limited thereto. The photointerrupter 28 in the present invention can detect the situation that the movable iron core 23A is in the attracting position or in the vicinity thereof by means of the operating rod 23.

[0084] [Sixth Modification]

[0085] In the above embodiment, the operation 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, the locking member for locking the cam 40 may be provided independently of the operation lever 23 .

[0086] [Seventh variant]

[0087] In the above-mentioned embodiment, the solenoid applied to the spring lock type safety switch is equivalent to the so-called "pull type" solenoid, and the solenoid applied to the solenoid lock type safety switch is equivalent to the so-called "push type" solenoid, but the solenoid applied to the drive control device involved in the present invention can also be applied to the so-called "self-holding type" solenoid that uses the attraction of the permanent magnet to hold the movable iron core at the attraction position. In this case, the holding current of the solenoid is zero (that is, Ih=0).

[0088] [Variant 8]

[0089] In the above embodiment, an example is shown in which the state of the movable iron core 23A (i.e., the state of the attraction position or the non-attraction position, etc.) is indirectly detected by detecting the position of the operating rod 23, but the component for position detection is not limited to the operating rod 23. Any movable component may be used as long as it is a component connected to the movable iron core 23A.

[0090] [9th variant]

[0091] In the above embodiment, the solenoid in which the movable iron core 23A reciprocates in the axial direction (i.e., moves in a straight line) is used as an example for explanation, but the present invention can also be applied to a solenoid of a type in which the movable iron core tilts (or rotates) around a fulcrum or a type in which the movable iron core rotates around an axis. Thus, the drive control device involved in the present invention can be applied to all electrical components that cause current to flow in a copper wire to generate a magnetic field to attract the movable iron core.

[0092] [Other variations]

[0093] The above embodiments and variations should be regarded as merely illustrative of the present invention in all aspects, and not as limitations of the present invention. For those skilled in the art of the present invention, even if it is not clearly stated in this specification, in consideration of the above teachings, it is possible to construct various variations or other embodiments using the principles of the present invention without departing from the concept and essential features of the present invention.

[0094] [Other application examples]

[0095] The present invention is not limited to the above-mentioned safety switch, but can be applied to various equipment and devices using a solenoid.

[0096] Industrial Application Possibility

[0097] The present invention is useful for a solenoid drive control device for achieving energy saving and reducing thermal risks caused by temperature increase.

[0098] Description of Reference Numerals

[0099] 1…safety switch; 2…switch body; 3…actuator; 40…cam; 22…solenoid; 22A…solenoid body; 23A…movable iron core (movable part); 25…contact switching block (moving body); 25A…rib (detected part); 25B1, 25B2, 25D1, 25D2…inclined surface (acting part); 28…photointerrupter (detecting part); 51…current control part; 100…drive control device; Imax…drive current (first current); Ih…holding current (second current).

Claims

1. A solenoid drive control device, comprising a solenoid body for attracting a movable part, wherein the solenoid body supports the movable part so that the movable part can be moved to an attraction position where the movable part is attracted by the solenoid body and a non-attraction position where the movable part is not attracted by the solenoid body, It is characterized in that The solenoid drive control device comprises: a detection unit configured to detect a state of the movable unit; and a current control unit that controls the current supplied to the solenoid body in accordance with the detection result of the detection unit so that a first current is supplied to the solenoid body when the movable unit is in the non-attracting position or a position near the non-attracting position, and a second current that is smaller than the first current is supplied to the solenoid body when the movable unit is in the attracting position or a position near the non-attracting position, The detection unit is used to detect that the movable part is at the non-attraction position or a position near the non-attraction position. When the detection unit fails, the current control unit supplies the first current to the solenoid body.

2. The solenoid drive control device according to claim 1, characterized in that: The movable part is provided with a moving body that moves by an action from the movable part, and the moving body is provided with an acting part that applies an action to a contact for controlling an external device and a detected part that is detected by the detecting part.

3. A safety switch comprising the solenoid drive control device according to claim 1, characterized in that: The safety switch has: a switch body having contacts; an actuator that is inserted and removed relative to the switch body; and a cam which is rotatable due to the insertion of said actuator, The movable portion of the solenoid functions to lock or unlock the rotation of the cam.

4. The safety switch according to claim 3, characterized in that: The movable part has a moving body that moves due to an action from the movable part. The moving body includes an acting portion that applies an action to the contact of the switch body, and a detected portion that is detected by the detecting portion.

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