Actuator unit and safety switch

Abstract

To absorb positional deviation from an actuator insertion hole in an arbitrary direction intersecting an insertion direction, improve durability, and smoothly perform the absorption of positional deviation.SOLUTION: An actuator unit 3 is provided with: an actuator 3A that has a leading end 30 insertable into an actuator insertion hole 20; and a support part 4 that movably supports a base end-side end 35B of the actuator 3A in an arrow B direction intersecting an arrow A direction being an insertion direction into the actuator insertion hole 20. The support part 4 has: a ball 40; and a retainer 41 that rotationally holds the ball, is provided different from the base end-side end 35B of the actuator 3A, and is movable in the arrow B direction. Positional deviation δ between the leading end 30 of the actuator 3A and the actuator insertion hole 20 is absorbed by the movement in the arrow B direction of the retainer 41 and the relative displacement of the base end-side end 35B of the actuator 3A from the retainer 41 in the arrow B direction.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an actuator unit and a safety switch including the same.

Background Art

[0002] At the entrance and exit of a dangerous area where industrial machines such as machine tools and industrial robots are installed, a safety switch that turns on / off according to the open / closed state of a door is provided.

[0003] Generally, a safety switch includes an actuator disposed on the door side, and a switch body disposed on the wall side, having an actuator insertion hole, and whose contacts are switched according to the movement of an internal operation rod. When the door is closed, the actuator on the door side is inserted into the actuator insertion hole of the switch body on the wall side, and the internal operation rod of the switch body moves to switch the contacts.

[0004] In such a safety switch, due to rattling of the door or displacement of the door itself, etc., the actuator may be displaced with respect to the actuator insertion hole. As a result, when the door is closed, the actuator may not be smoothly inserted into the actuator insertion hole. Therefore, various measures have been taken to prevent such a situation from occurring.

[0005] For example, in the actuator described in Japanese Patent Application Laid-Open No. 2017-91877, the operation key (2) is supported by the base (3) so as to be swingable, and by the biasing force of the torsion coil spring (41), the operation key (2) after swinging is returned to the reference position. Thus, even when the rattling of the door is large, when the operation key (2) is inserted, the operation key (2) swings, so that the operation key (2) is inserted into the key insertion holes (103, 104) of the switch body (see paragraphs

[0037] ,

[0038] ,

[0044] , FIG. 1, FIGS. 13 to 15 of the same publication).

[0006] In the key switch described in Japanese Patent Application Laid-Open No. 8-138500, the key body (9) of the operation key (3) is slidably provided on the support shaft portion (12) of the holder portion (8), and the elastic body (13) biases the key body (9) to the slide neutral position. Thus, even when assembly errors or misalignments occur between the operation key (3) and the switch body (2), when the operation key (3) is inserted, the operation key (3) slides, so that the operation key (3) is inserted into the key hole (6) of the switch body (2) (see paragraphs

[0009] and

[0020] and FIGS. 1 to 3 of the same publication).

[0007] In the actuator for a safety switch described in Japanese Patent Application Laid-Open No. 11-317132, the base portion (3) of the key (2) is attached via a circular PTFE slide bearing (or roller bearing) (9) to the holder (1) so as to be slidable, and the spring (10) biases the key (2) to the central position. Thus, by displacing the base portion (3) of the key (2) along the mounting surface of the slide bearing (9), the misalignment between the actuator and the insertion slot of the safety switch is corrected (see claim 1, paragraphs

[0011] and

[0012] , and FIGS. 1, 3, and 4 of the same publication).

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the device described in Japanese Patent Application Laid-Open No. 2017-91877, when there is a misalignment between the operation key (2) and the key insertion openings (103, 104) of the switch body (100), the operation key (2) swings when inserted into the key insertion openings (103, 104) of the operation key (2) to absorb the misalignment. Therefore, it can cope with misalignments in the swinging direction (i.e., within the swinging plane) of the operation key (2), but cannot cope with misalignments in a direction intersecting (for example, orthogonal) to the swinging direction.

[0009] In the invention described in Japanese Patent Application Laid-Open No. 8-138500, when there is a displacement between the key body (9) of the operation key (3) and the key hole (6) of the switch body (2), when the key body (9) is inserted into the key hole (6), the key body (9) slides to absorb the displacement. Therefore, it can cope with the displacement in the sliding direction of the key body (9) (that is, within the sliding plane), but it cannot cope with the displacement in the direction intersecting (for example, orthogonal) to the sliding direction.

[0010] On the other hand, in the invention described in Japanese Patent Application Laid-Open No. 11-317132, when there is a displacement between the key (2) and the insertion slot of the safety switch, when the key (2) is inserted into the insertion slot, the key (2) moves along the mounting surface of the slide bearing (9) to absorb the displacement. Therefore, it can cope with the displacement in any direction.

[0011] However, when the door is closed with a displacement between the key (2) and the insertion slot of the safety switch, an excessive impact load due to the inertia of the door acts on the base (3) of the key (2), and this directly acts on the PTFE slide bearing. Therefore, the PTFE slide bearing may be damaged, and there is a problem with durability. In addition, in the invention described in Japanese Patent Application Laid-Open No. 11-317132, it is described that a roller bearing may be used instead of the PTFE slide bearing. However, when a roller bearing is used, the base (3) of the key (2) can only be displaced in the rolling direction of the roller bearing. Therefore, it can cope with the displacement in the rolling direction, but it cannot cope with the displacement in the direction intersecting (for example, orthogonal) to the rolling direction.

[0012] The present invention has been made in view of such a conventional situation. The problem to be solved by the present invention is to provide an actuator unit and a safety switch equipped with the same that can absorb the displacement with respect to the actuator insertion hole in any direction intersecting the insertion direction, improve durability, and further smoothly absorb the displacement.

Means for Solving the Problem

[0013] The actuator unit according to the present invention includes an actuator having a tip portion insertable into an actuator insertion hole, and a support portion that movably supports the base end side end portion of the actuator in a second direction intersecting a first direction which is the insertion direction of the actuator into the actuator insertion hole. The support portion has a ball and a holding portion that rotatably holds the ball, is provided separately from the base end side end portion of the actuator, and is movable in the second direction. The positional deviation between the tip portion of the actuator and the actuator insertion hole is absorbed by the movement of the holding portion in the second direction and the relative movement of the base end side end portion of the actuator with respect to the holding portion in the second direction.

[0014] According to the present invention, the base end side end portion of the actuator is movably supported in a second direction intersecting a first direction which is the insertion direction of the actuator by a support portion including a rotatable ball and a holding portion that holds the ball and is movable in the second direction. Further, the positional deviation between the tip portion of the actuator and the actuator insertion hole is absorbed by the movement of the base end side end portion of the actuator and the holding portion in the second direction. Thus, the positional deviation with respect to the actuator insertion hole can be absorbed in an arbitrary direction intersecting the insertion direction. Moreover, according to the present invention, since the base end side end portion of the actuator is supported by the support portion having a rotatable ball, even when an excessive thrust load acts on the base end side end portion of the actuator due to an excessive load acting on the tip portion of the actuator when a positional deviation with respect to the actuator insertion hole occurs, the base end side end portion of the actuator can be reliably supported by the ball of the support portion, thereby improving the durability of the actuator unit. In addition, since rolling friction is much smaller than sliding friction, by using a ball, the friction coefficient can be made smaller than when using a slide bearing, thereby realizing smooth movement of the actuator and further improving the durability.

[0015] Furthermore, according to the present invention, since the holding portion that rotatably holds the ball and is movable in the second direction is provided separately from the proximal end side end portion of the actuator, when the distal end portion of the actuator is displaced with respect to the actuator insertion hole during the insertion of the actuator, the holding portion moves in the second direction without being restricted by the proximal end side end portion of the actuator while allowing the rotation of the ball. As a result, the proximal end side end portion of the actuator can move smoothly in the second direction, and the displacement can be absorbed smoothly.

[0016] In the present invention, when the displacement between the distal end portion of the actuator and the actuator insertion hole is δ, the amount of movement of the holding portion in the second direction is h, and the relative amount of movement of the proximal end side end portion of the actuator with respect to the holding portion in the second direction is b, the relational expression of δ = h + b holds.

[0017] In the present invention, a first elastic support member that elastically supports the actuator in the second direction is provided on the actuator. In this case, the actuator after movement can be returned to the original position before movement by the biasing force of the first elastic support member.

[0018] In the present invention, a second elastic support member that elastically supports the holding portion in the second direction is provided on the support portion. In this case, the holding portion after movement can be returned to the original position before movement by the biasing force of the second elastic support member.

[0019] In the present invention, the actuator extends between the distal end portion and the proximal end side end portion, the proximal end side end portion and the support portion are accommodated in the case, and the case has an opening that allows the movement of the actuator in the second direction.

[0020] In the present invention, the distal end portion has a tapered surface or a convex arc-shaped surface. In this case, when the distal end portion abuts against the opening edge portion of the actuator insertion hole due to the displacement, the proximal end side end portion of the actuator can move smoothly to the side that absorbs the displacement.

[0021] In the present invention, the tip of the actuator has a locking hole, and the locking hole is locked to a locking member inside a switch body having an actuator insertion hole.

[0022] In the present invention, the actuator has a shaft portion extending between the tip portion and the base end side portion, a step is formed between the shaft portion and the tip portion, and the step is locked to a locking member inside a switch body having an actuator insertion hole.

[0023] The safety switch according to the present invention includes an actuator unit according to the present invention and a switch body having an actuator insertion hole.

Effect of the Invention

[0024] As described above, according to the present invention, the displacement between the tip of the actuator and the actuator insertion hole can be absorbed in an arbitrary direction intersecting the insertion direction. Moreover, according to the present invention, even when an excessive thrust load acts on the actuator due to an excessive load acting on the tip of the actuator at the time of displacement, the base end side portion of the actuator can be reliably supported by the ball of the support portion, and the durability of the actuator unit can be improved. Further, according to the present invention, the base end side portion of the actuator can move smoothly in the second direction, and the absorption of displacement can be performed smoothly.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Embodiments for Carrying Out the Invention

[0026] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. FIGS. 1 to 4 are diagrams for explaining an actuator unit and a safety switch provided therewith according to an embodiment of the present invention. Each figure shows the appearance of the safety switch. FIGS. 1 and 2 are perspective views of the safety switch, FIG. 3 is a front view thereof, and FIG. 4 is a plan view.

[0027] As shown in FIGS. 1 to 4, the safety switch 1 according to this embodiment includes, for example, a switch body 2 attached to a wall or a fixed door (not shown), and an actuator unit 3 attached to, for example, a slide-type movable door (not shown) and provided so as to be insertable and removable with respect to the switch body 2. In each figure, arrow A indicates the insertion direction (first direction) of the actuator unit 3.

[0028] The switch body 2 has one or a plurality of actuator insertion holes 20. The actuator insertion hole 20 is a through hole that penetrates the wall portion of the switch body 2, for example, a through hole having a rectangular cross section, and the opening edge portion thereof has a tapered surface 20a whose opening width gradually decreases from the outer surface of the wall portion of the switch body 2 toward the inside of the switch body 2. In FIG. 4, the dashed-dotted line 2C L indicates the center line of the actuator insertion hole 20. Although not shown, inside the switch body 2, a switchable contact is provided, and a locking member (described later) that locks to the inserted actuator unit 3 is provided.

[0029] The actuator unit 3 has an actuator 3A having a tip portion 30 that can be inserted into the actuator insertion hole 20 of the switch body 2, and a base portion 3B that houses the base end side end portion (described later) of the actuator 3A. The tip portion 30 is, for example, plate-shaped (that is, having a rectangular cross section), and flat inclined surfaces 30t are respectively formed at each corner portion on the tip side thereof by chamfering, and the tip side portion has a tapered surface that gradually tapers toward the tip. Instead of the inclined surface, a rounded surface (that is, a convex arc-shaped surface) may be formed, or the entire tip side portion may form a convex arc-shaped surface. A locking hole 30b, for example, rectangular, that penetrates the tip portion 30 in the thickness direction is formed in the tip portion 30. In FIG. 4, the dashed-dotted line 3C L indicates the longitudinal center line of the actuator 3A. In this example, the center line 3C L coincides with the center line 2C of the actuator insertion hole 20 of the switch body 2 L and the state is shown.

[0030] The base portion 3B has a box-shaped case 32 that houses the proximal end portion (described later) of the actuator 3A, and a thin plate-shaped lid 33 that covers the rear surface side opening on the side opposite to the actuator 3A side in the case 32. A plurality of screw insertion holes 32b and 33b into which mounting screws (not shown) for attaching the actuator unit 3 to the movable door are inserted are respectively formed in the case 32 and the lid 33. Note that reference numeral 33c in FIG. 2 is a screw insertion hole into which a mounting screw (not shown) for fixing the lid 33 to the case 32 is inserted.

[0031] Next, the details of the proximal end portion of the actuator 3A and the support portion that supports it will be described with reference to FIGS. 5 to 13. FIGS. 5 to 9 show longitudinal sections of the actuator unit 3, FIGS. 10 to 12 show cross sections thereof, and FIG. 13 shows the overall configuration of the support portion. Among the cross-sectional views, only the cross section in FIG. 5 is shown with hatching, and hatching is omitted in the other figures.

[0032] As shown in FIGS. 5 to 9, the proximal end portion 31 of the actuator 3A is composed of a substantially rhombic plate-shaped portion extending radially outward (see FIG. 1), and a screw hole (female screw) 31c extending in the axial direction is formed in the boss portion 31C at the center thereof. On the other hand, a screw 34 extending in the axial direction is disposed in the case 32, and the shaft portion (male screw) 34a of the screw 34 is screwed into the screw hole 31c of the boss portion 31C and fixed. A flange member 35 is fixed to the outer periphery of the shaft portion 34a of the screw 34. The flange member 35 has flange portions 35B and 35B' that are arranged with an axial interval 35C on the proximal end side and project radially outward, respectively. The flange portion 35B is disposed on the most proximal end side.

[0033] The shaft portion 34a of the screw 34 and the flange member 35 extend to the outside of the case 32 through an opening 32a formed through the wall portion 32A on one end side of the case 32. The inner diameter of the opening 32a is larger than the outer diameter of the flange member 35 disposed within the opening 32a, and a clearance allowing radial movement of the flange member 35 is formed between the opening 32a and the flange member 35. The tip portion 35A of the flange member 35 is disposed within a recess 31d formed in the base end portion 31 of the actuator 3A. A packing 36, for example made of rubber, is provided within the recess 31d, and one end of the packing 36 is fixed to the tip portion 35A of the flange member 35. The other end of the packing 36 is fixed to a ring-shaped seal member 37 made of, for example, resin. The seal member 37 is disposed on the outer peripheral side of the opening 32a formed in the wall portion 32A of the case 32, and is provided so as to be slidable in an arbitrary radial direction of the opening 32a on the outer surface 32c of the wall portion 32A.

[0034] The actuator 3A, the screw 34, the flange member 35, the packing 36, and the seal member 37 are integrally configured as a whole. Thus, the flange portion 35B on the most proximal end side of the flange member 35 substantially constitutes the base end side end portion of the actuator 3A. Between the flange portion 35B on the most proximal end side of the flange member 35 and the lid body 33, a support portion 4 is provided separately from the flange portion (i.e., the base end side end portion of the actuator 3A) 35B on the most proximal end side and supports the flange portion 35B so as to be slidable in an arbitrary radial direction. The support portion 4 has a plurality of balls 40 and is composed of a ball bearing structure movable in a direction of arrow B (second direction) intersecting (preferably orthogonal) to the direction of arrow A (first direction), which is the insertion direction of the actuator 3A, and supports the base end side end portion 35B of the actuator 3A so as to be movable in the direction of arrow B (details will be described later). Note that the direction of arrow B is not limited to within the plane of FIG. 5, but includes any direction intersecting (preferably orthogonal) to the direction of arrow A, that is, any radial direction intersecting (preferably orthogonal) to the axial direction.

[0035] Inside the internal space 32C of the case 32, torsion coil springs (first elastic support members) 38, 38' are provided to elastically support the actuator 3A in the direction of arrow B via the flange member 35 and the screw 34. The torsion coil springs 38, 38' are disposed between the respective flange portions 35B, 35B' of the flange member 35, and are composed of, for example, high-tensile steel wires such as piano wires, other steel wires, metal wires, etc.

[0036] As shown in FIG. 10, which is a cross-sectional view taken along the line X-X of FIG. 9, the torsion coil spring 38 is composed of a pair of left and right torsion coil springs 381, 382, and each torsion coil spring 381, 382 is attached to columnar posts 391, 392 extending from the wall surface of the case 32, respectively. One arm portion of each torsion coil spring 381, 382 is locked to the upper inner wall surface of the case 32, and the other arm portion is elastically abutted against the outer peripheral surface of the flange member 35 so as to sandwich it from the left and right. Similarly, the torsion coil spring 38' is composed of a pair of left and right torsion coil springs 381', 382', and each torsion coil spring 381', 382' is attached to posts 391', 392' extending from the wall surface of the case 32, respectively. One arm portion of each torsion coil spring 381', 382' is locked to the lower inner wall surface of the case 32, and the other arm portion is elastically abutted against the outer peripheral surface of the flange member 35 so as to sandwich it from the left and right.

[0037] With this configuration, the flange member 35 (and thus also the actuator 3A) is elastically supported from the outer peripheral side, and even when the flange member 35 moves in any direction in the radial direction (i.e., the direction of arrow B), due to the action of the elastic repulsive force accompanying the elastic deformation of the arm portions of the torsion coil springs 381, 382, 381', 382', the flange member 35 (and thus the actuator 3A) returns to its original position. Therefore, the torsion coil springs 381, 382, 381', 382' have an automatic centering function with respect to the actuator 3A.

[0038] As shown in FIG. 9, FIG. 11 which is a cross-section taken along line XI-XI thereof, and FIGS. 12 and 13, the support portion 4 has a plurality (six in this example) of balls (i.e., steel balls) 40 made of, for example, steel that can contact the side surface 35d of the flange portion 35B, and a retainer (holding portion) 41 made of, for example, resin for rotatably supporting each ball 40. Each ball 40 is provided so as to be able to contact the inner surface of the lid body 33 as well. In FIGS. 5 to 8, for the sake of illustration, a gap is shown to be formed between each ball 40 and the side surface 35d of the flange portion 35B, but as shown in FIG. 9, each ball 40 preferably contacts the side surface 35d of the flange portion 35B.

[0039] The retainer 41 is a substantially ring-shaped member provided separately from the flange portion 35B at the most proximal end side of the flange member 35 (i.e., the proximal end side end portion of the actuator 3A), and has a plurality (six in this example) of cylindrical holding holes 41a for rotatably supporting each ball 40. Each holding hole 41a is preferably arranged at equal intervals on the circumference. The retainer 41 has a plurality (three in this example) of plate-like arm-shaped members (second elastic support members) 42 that extend into the internal space of the retainer 41 and can act as resin leaf springs. One end of each arm-shaped member 42 is fixed to the ring-shaped portion on the outer peripheral side of the retainer 41, and the other end (free end) is arranged at the center of the retainer 41. Further, the retainer 41 has a plurality (three in this example) of compression springs (second elastic support members) 43 disposed in the internal space of the retainer 41. One end of each compression spring 43 is in pressure contact with the ring-shaped portion on the outer peripheral side of the retainer 41, and the other end is arranged at the center of the retainer 41 and is in pressure contact with the other end of the corresponding arm-shaped member 42. Thereby, the other end of each arm-shaped member 42 is elastically in contact with the outer peripheral surface of the screw 34.

[0040] With this configuration, the retainer 41 is elastically supported from the inner peripheral side. Even if the retainer 41 moves in any radial direction, due to the action of the elastic repulsive force accompanying the elastic deformation of each arm-shaped member 42 and each compression spring 43, the retainer 41 returns to its original position before movement. Therefore, each arm-shaped member 42 and each compression spring 43 have an automatic centering function with respect to the retainer 41.

[0041] Next, the operation and effects of this embodiment will be described with reference to FIGS. 14 to 21 while referring to FIGS. 1 to 4. FIGS. 14 to 16 are schematic diagrams showing a simplified view of FIG. 5, and FIGS. 17 to 21 are diagrams showing the operation at the time of inserting the actuator in chronological order.

[0042] When the movable door is moved in the closing direction from the state shown in FIGS. 1 to 4, the actuator 3A of the actuator unit 3 moves in the direction of arrow A. As shown in FIGS. 17 and 21, the actuator 3A is inserted into the inside of the switch body 2 through the actuator insertion hole 20 of the switch body 2. At the time of this insertion, the center line 3C of the actuator 3A L coincides with the center line 2C of the actuator insertion hole 20 of the switch body 2 L (see FIGS. 4 and 17). Therefore, the tip portion 30 of the actuator 3A is smoothly inserted into the inside of the switch body 2 without interfering with the tapered surface 20a of the actuator insertion hole 20. After the insertion of the actuator 3A, as shown in FIG. 21, the locking hole 30b of the tip portion 30 of the actuator 3A is locked by the locking member SR inside the switch body 2. Thereby, the actuator 3A is locked and prevented from coming off. From this state, the contacts (not shown) inside the switch body 2 are switched, and the drive of a machine such as a robot is started.

[0043] Next, as shown in FIG. 18, assume that the center line 3C of the actuator 3A L is displaced with respect to the center line 2C of the actuator insertion hole 20 of the switch body 2 L and let the amount of displacement (displacement) at that time be δ. Here, the center line 3CL is the center line 2C L Take as an example the case where it is displaced downward by a distance δ with respect to it.

[0044] From this state, when the movable door is moved in the closing direction, the actuator 3A of the actuator unit 3 moves in the direction of arrow A, and as shown in FIG. 19, the tip 30 of the actuator 3A abuts on the tapered surface 20a of the actuator insertion hole 20 of the switch body 2. At this time, the inclined surface 30t of the tip 30 abuts on the tapered surface 20a, and therefore, during the closing of the movable door, the inclined surface 30t of the tip 30 slides along the tapered surface 20a and tries to move obliquely upward as shown in the figure. At this time, the actuator 3A moves forward (to the left in FIG. 19) integrally with the base portion 3B, and relatively moves in the direction of arrow B (preferably orthogonal) intersecting the direction of arrow A with respect to the base portion 3B (see FIG. 20).

[0045] Here, as described above, the actuator 3A is integrally formed with the screw 34, the flange member 35, the packing 36, and the seal member 37. Therefore, when the actuator 3A moves in the direction of arrow B, the actuator 3A, the screw 34, the flange member 35, the packing 36, and the seal member 37 move integrally (therefore, the seal member 37 slides on the outer surface 32c of the wall portion 32A of the case 32).

[0046] The operation of the actuator unit 3 at this time will be described with reference to the schematic diagrams of FIGS. 14 to 16. FIG. 14 corresponds to FIGS. 18 and 19, and FIG. 15 corresponds to FIG. 20. Also, FIG. 16(a) corresponds to FIGS. 18 and 19, and FIG. 16(b) corresponds to FIG. 20.

[0047] Before the tip 30 of the actuator 3A comes into contact with the tapered surface 20a of the actuator insertion hole 20 of the switch body 2, as shown in FIG. 14, the actuator 3A is disposed at the center (or substantially the center) of the opening 32a of the case 32 and is elastically supported at the center of the opening 32a by the respective torsion coil springs 38, 38'. Further, the retainer 41 of the support portion 4 is elastically supported concentrically (or substantially concentrically) with the actuator 3A by the respective compression springs 43.

[0048] Next, when the tip 30 of the actuator 3A comes into contact with the tapered surface 20a of the actuator insertion hole 20 of the switch body 2, in FIG. 14, the flange portion (i.e., the proximal end side end portion of the actuator 3A) 35B at the most proximal end side of the flange member 35 provided integrally with the actuator 3A comes into pressure contact with the ball 40 of the support portion 4, and the ball 40 is sandwiched between the flange portion 35B and the lid body 33.

[0049] From this state, when the actuator 3A starts to move in the direction of arrow B, as shown in FIG. 15, the flange portion 35B moves in the same direction together with the actuator 3A, so that the flange portion 35B causes the ball 40 to roll in the rightward direction in the drawing (i.e., the direction of arrow B). During this rolling motion, the ball 40 rolls on the lid body 33. However, since the retainer 41 that supports the ball 40 is provided separately from the flange portion 35B, the retainer 41 moves in the direction of arrow B without being restricted by the flange portion 35B. At this time, since the entire support portion 4 including the retainer 41 and the ball 41 moves, the flange portion 35B also moves in the direction of arrow B. Further, during the rolling motion of the ball 40, the ball 40 rotates within the retainer 41. Due to the rotation of the ball 40, the flange portion 35B with which the ball 40 makes rolling contact moves in the direction of arrow B. This movement of the flange portion 35B is a relative movement with respect to the retainer 41.

[0050] Thus, when the actuator 3A moves in the direction of arrow B, the amount of movement of the flange portion 35B that moves together with the actuator 3A is the sum of the amount of movement caused by the retainer 41 (and thus the support portion 4) moving in the direction of arrow B and the amount of movement caused by the flange portion 35B moving relative to the retainer 41. When the total amount of movement of the flange portion 35B becomes equal to the displacement δ of the actuator 3A, the displacement of the actuator 3A is absorbed. At this time, as shown in FIG. 20, the actuator 3A is inserted into the inside of the switch body 2 through the actuator insertion hole 20, and the locking hole 30b at the tip portion 30 of the actuator 3A is locked by the locking member SR inside the switch body 2, and the actuator 3A is locked (see FIG. 21).

[0051] Here, FIG. 16(a) schematically shows the state before the movement of the actuator 3A, and FIG. 16(b) schematically shows the state after the movement of the actuator 3A. In each figure, the contact points between the ball 40, the flange portion 35B, and the lid body 33 are indicated by black circles, and the contact points are connected by line segments d. Let the diameter of the ball 40 be d (radius be r). Also, the white triangles indicate the positions corresponding to the black circles on the flange portion 35B and the lid body 33, respectively.

[0052] In FIG. 16(b), if the amount of movement of the ball 40 relative to the lid body 33 due to the rolling motion of the ball 40 on the lid body 33 is h1, and the rotation angle of the ball 40 at this time is θ, h1 = rθ …(1) it can be expressed as. If the amount of movement of the retainer 41 due to the rolling motion of the ball 40 is h2, h2 = h1…(2) is obtained. Also, if the amount of movement of the flange portion 35 with which the ball 40 makes rolling contact due to the rotation of the ball 40 during the rolling motion is b, b = rθ …(3) it can be expressed as. From equations (1) to (3), b = h2…(4) is obtained. The total amount of movement δ of the actuator 3A is δ = h2 + b = 2h2 (∵ Equation (4)) That is, when h2 is replaced with h, δ = 2h ∴ h = δ / 2 …(5) It becomes like this. (5) Equation means that when there is a displacement in the actuator 3A, if the retainer 41 moves by half of that distance, the displacement of the actuator 3A can be absorbed. In Fig. 16, an example of h1 = h2 = 2.5 (mm), b = 2.5 (mm), and δ = 5.0 (mm) is shown.

[0053] Summarizing the above, the displacement δ between the tip 30 of the actuator 3A and the actuator insertion hole 20 of the switch body 2 is absorbed by the movement of the retainer 41 in the direction of arrow B and the relative movement of the flange portion 35B, which is the base end side end of the actuator 3A with respect to the retainer 41, in the direction of arrow B. When the movement amount of the retainer 41 in the direction of arrow B is h and the relative movement amount of the flange portion 35B with respect to the retainer 41 in the direction of arrow B is b, the relational expression δ = h + b is satisfied. Further, when there is no slippage between the ball 40, the flange portion 35B, and the lid body 33, since h = b, the relational expression δ = 2h holds.

[0054] Thus, according to this embodiment, the base end side end portion 35B of the actuator 3A is movably supported in the direction of arrow B that intersects the direction of arrow A, which is the insertion direction of the actuator 3A, by the support portion 4 including the rotatable ball 40 and the retainer 41 that holds the ball 40 and is separate from the base end side end portion 35B. Also, the displacement between the tip 30 of the actuator 3A and the actuator insertion hole 20 is absorbed by the movement of the retainer 41 in the direction of arrow B and the relative movement of the base end side end portion 35B with respect to the retainer 41 in the direction of arrow B. Therefore, the displacement with respect to the actuator insertion hole 20 can be absorbed in an arbitrary direction that intersects the insertion direction.

[0055] Moreover, according to this embodiment, since the proximal end side end portion 35B of the actuator 3A is supported by the support portion 4 having the rotatable ball 40, even when an excessive thrust load acts on the proximal end side end portion 35B of the actuator 3A due to an excessive load acting on the distal end portion 30 of the actuator 3A when displacement occurs with respect to the actuator insertion hole 20, the proximal end side end portion 35B of the actuator 3A can be reliably supported by the ball 40 of the support portion 4. Thereby, the durability of the actuator unit 3 can be improved. Further, since rolling friction is much smaller than sliding friction, by using the ball 40, the friction coefficient can be made smaller than in the case of using a slide bearing, and thereby, smooth movement of the actuator 3A can be realized and the durability can be further improved.

[0056] Furthermore, according to this embodiment, since the retainer 41 that rotatably holds the ball 40 and is movable in the direction of arrow B is provided separately from the proximal end side end portion 35B of the actuator 3A, when the distal end portion 30 of the actuator 3A is displaced with respect to the actuator insertion hole 20 during insertion of the actuator 3A, the retainer 41 moves in the direction of arrow B without being restricted by the proximal end side end portion 35B of the actuator 3A while allowing the rotation of the ball 40. Thereby, the proximal end side end portion 35B of the actuator 3A can smoothly move in the direction of arrow B, and displacement can be smoothly absorbed.

[0057] Also, when the distal end portion 30 of the actuator 3A is inserted into the inside of the switch body 2, the actuator 3A moves upward with respect to the base portion 3B (see FIG. 20). At this time, the proximal end side end portion 35B of the actuator 3A also moves upward, elastically deforming the upper torsion coil springs 381 and 382 in FIG. 10 upward. Therefore, at this time, an elastic repulsive force accompanying the elastic deformation of the torsion coil springs 381 and 382 acts downward on the outer peripheral surface of the proximal end side end portion 35B of the actuator 3A.

[0058] Therefore, when the movable door is opened, as the tip 30 of the actuator 3A moves away from the actuator insertion hole 20 of the switch body 2 as the movable door moves, due to the elastic repulsive forces of the torsion coil springs 381 and 382 acting on the base end side end portion 35B of the actuator 3A, the actuator 3A moves downward and returns to the state before insertion.

[0059] In the above embodiment, the case where the actuator 3A is displaced downward with respect to the actuator insertion hole 20 and the base end side end portion 35B of the actuator 3A elastically deforms the upper torsion coil springs 381 and 382 upward when absorbing the displacement has been described as an example. However, in the case of upward displacement, the base end side end portion 35B abuts against the lower torsion coil springs 381' and 382' and elastically deforms them downward, and in the case of lateral displacement, the base end side end portion 35B abuts against the torsion coil springs 381 and 382' or 382 and 381' and elastically deforms these torsion coil springs laterally.

[0060] Also, when the retainer 41 moves in the direction of arrow B when the actuator 3A is inserted into the actuator insertion hole 20, in FIG. 11, the retainer 41 moves relative to the screw 34. As a result, the corresponding compression spring 43 elastically deforms and an elastic repulsive force acts between the arm-shaped member 42 and the ring-shaped portion on the outer peripheral side of the retainer 41. Due to the action of this elastic repulsive force, when the actuator 3A moves away from the actuator insertion hole 20, the retainer 41 returns to its original position.

[0061] In the above embodiment, an example in which the torsion coil springs 38 and 38' are used as the first elastic support member and the compression coil spring 43 is used as the second elastic support member has been shown, but the application of the present invention is not limited thereto. Other springs and elastic support members made of various elastic bodies may be adopted.

[0062] In the actuator unit 2 according to the above embodiment, as shown in FIGS. 1 to 4, at the upper and lower ends of the back surface of the base end portion 31 of the actuator 3A, protrusions 30p and 30p' protruding toward the case 32 are respectively provided, and at the upper and lower ends of the outer surface 32c of the case 32, a pair of left and right protrusions 32p and 32p' protruding toward the actuator 3A are respectively provided. Each protrusion 32p is arranged at intervals on both the left and right sides of the protrusion 30p, and each protrusion 32p' is arranged at intervals on both the left and right sides of the protrusion 30p'. These protrusions are for restricting the rotation of the actuator 3A around the center line 3C L and also enable the actuator 3A to rotate within the range restricted by the protrusions 32p and 32p'. Thereby, even if the tip portion 30 of the actuator 3A has some rotational deviation around the center line 3C L around the center line 3C (that is, a deviation caused by the tip portion 30 rotating somewhat in the circumferential direction around the center line 3C L ), the deviation can be absorbed by the rotation of the actuator 3A around the center line 3CL.

[0063] <Modification Example> In the above embodiment, the case where the tip portion 30 of the actuator 3A is plate-shaped (that is, has a rectangular cross-section) has been described as an example, but the application of the present invention is not limited thereto. FIGS. 22 and 23 show a safety switch including an actuator unit and a switch body according to a modification example of the present invention. In these figures, the same reference numerals as in the above embodiment denote the same or corresponding parts.

[0064] As shown in FIG. 22, the tip portion 30 of the actuator 3A is, for example, a hemispherical protrusion, and has a convex arc-shaped surface 30r disposed on the tip side and a flat surface 30c disposed on the rear end side. The flat surface 30c is integrally connected to the tip of, for example, a columnar shaft portion 31J extending in the axial direction. The shaft portion 31J is a member having a smaller diameter than the tip portion 30, and the flat surface 30c forms a step with respect to the tip of the shaft portion 31J. On the other end side of the shaft portion 31J, a base end side end portion (not shown) of the actuator 3A is provided. That is, the shaft portion 31J extends between the tip portion 30 and the base end side end portion of the actuator 3A. The actuator insertion hole 20 of the switch body 2 is, for example, a circular tapered hole penetrating the wall portion of the switch body 2, and gradually decreases in diameter from the outer surface of the wall portion of the switch body 2 toward the inside of the switch body 2, and has a tapered surface 20a. Although not shown, the internal structure of the base portion 3B is the same as that of the above-described embodiment, and the configuration of the support portion provided separately from the base end side end portion of the actuator 3A is also the same as that of the above-described embodiment.

[0065] FIG. 22 shows the state before the insertion of the actuator 3A when the tip portion 30 of the actuator 3A is displaced downward by a displacement δ with respect to the actuator insertion hole 20 of the switch body 2. When the movable door is moved in the closing direction from the state shown in the figure, the actuator 3A moves in the direction of arrow A, and the convex arc-shaped surface 30r of the tip portion 30 of the actuator 3A abuts against the tapered surface 20a of the actuator insertion hole 20 of the switch body 2, and the convex arc-shaped surface 30r of the tip portion 30 tries to move obliquely upward as shown in the figure while sliding on the tapered surface 20a along the tapered surface 20a. At this time, in addition to the pressing force in the direction opposite to the direction of arrow A, a pressing force in the direction of arrow B intersecting (preferably orthogonal) with the direction of arrow A acts on the actuator 3A.

[0066] As a result, as described with reference to FIGS. 14 to 16 of the above embodiment, when the proximal end side end portion of the actuator 3A rolls and rotates the ball of the support portion, the displacement δ of the actuator 3A can be absorbed. When the actuator 3A is inserted into the actuator insertion hole 20, as shown in FIG. 23, the locking member SR inside the switch body 2 locks the flat surface 30c that forms a step between the tip end portion 30 and the shaft portion 31J of the actuator 3A, thereby locking the actuator 3A.

[0067] In the above embodiment, the protrusions 30p, 30p', 32p, and 32p' are provided to restrict the rotation of the actuator 3A around the center line 3C during use. However, in this modification, since the cross-sectional shapes of the tip end portion 30 and the shaft portion 31J of the actuator 3A are circular, it is not necessary to provide such protrusions. L

[0068] The above-described embodiments and each modification should be regarded only as illustrative examples of the present invention in every respect and are not limiting. Those skilled in the art related to the present invention can construct various modifications and other embodiments that adopt the principles of the present invention without departing from the spirit and essential features of the present invention when considering the above teachings even without explicit description in this specification.

Industrial Applicability

[0069] The present invention is useful for an actuator unit and a safety switch including the same.

Explanation of Reference Numerals

[0070] 1: Safety switch 2: Switch body 20: Actuator insertion hole 3: Actuator unit 3A: Actuator 30: Tip end portion 30b: Locking hole​ 30t: Tapered surface 30r: Convex arc-shaped surface 31J: Shaft portion 32: Case 32a: Opening 35B: Flange portion on the most proximal side (proximal end portion of the actuator) 38, 38’: Twisted coil spring (first elastic support member) 4: Support portion 40: Ball 41: Retainer (holding portion) 42: Arm-shaped member (second elastic support member) 43: Compression spring (second elastic support member) SR: Locking member A: Actuator insertion direction (first direction) B: Direction intersecting the actuator insertion direction (second direction) δ: Displacement h: Movement amount of the retainer b: Relative movement amount of the actuator with respect to the retainer

Prior Art Documents

Patent Documents

[0071]

Patent Document 1

[0037] ,

[0038] ,

[0044] , Figures 1, 13 to 15)

Patent Document 2

[0009] ,

[0020] , Figures 1 to 3)

Patent Document 3

[0011] ,

[0012] , Figures 1, 3, 4)

Claims

1. An actuator unit, comprising: an actuator having a tip portion insertable into an actuator insertion hole; a support portion that movably supports a proximal end side end portion of the actuator in a second direction that intersects a first direction which is an insertion direction of the actuator into the actuator insertion hole; the support portion having a ball and a holding portion that rotatably holds the ball, is provided separately from the proximal end side end portion of the actuator, and is movable in the second direction; a misalignment between the tip portion of the actuator and the actuator insertion hole is absorbed by movement of the holding portion in the second direction and relative movement of the proximal end side end portion of the actuator with respect to the holding portion in the second direction; An actuator unit, characterized in that.

2. In Claim 1, when a misalignment between the tip portion of the actuator and the actuator insertion hole is δ, a movement amount of the holding portion in the second direction is h, and a relative movement amount of the proximal end side end portion of the actuator with respect to the holding portion in the second direction is b, δ = h + b a relational expression is established; An actuator unit, characterized in that.

3. In Claim 1, the actuator is provided with a first elastic support member that elastically supports the actuator in the second direction; An actuator unit, characterized in that.

4. In Claim 1, the support portion is provided with a second elastic support member that elastically supports the holding portion in the second direction; An actuator unit, characterized in that.

5. In Claim 1, the actuator extends between the tip portion and the proximal end side end portion, the proximal end side end portion and the support portion are housed in a case, and the case has an opening that allows movement of the actuator in the second direction; An actuator unit, characterized in that.

6. In Claim 1, the tip portion of the actuator has a tapered surface or a convex arc-shaped surface; An actuator unit, characterized in that.

7. In Claim 1, the tip portion of the actuator has a locking hole, and the locking hole is locked to a locking member inside a switch body having the actuator insertion hole. An actuator unit characterized by the above.

8. In Claim 1, the actuator has a shaft portion extending between the tip end portion and the base end side portion, a step is formed between the shaft portion and the tip end portion, and the step is configured to be locked to a locking member inside the switch body having the actuator insertion hole. An actuator unit characterized by the above.

9. The actuator unit according to Claim 1, a switch body having the actuator insertion hole, A safety switch comprising the above.

Images