JP7712738B2 - Actuator units and safety switches - Google Patents

Description

The present invention relates to an actuator unit and a safety switch equipped with the same.

At the entrances and exits of dangerous areas where industrial machinery such as machine tools and industrial robots are installed, there are safety switches that turn on and off depending on whether the door is open or closed.

Generally, a safety switch is equipped with an actuator that is placed on the door side, and a switch body that is placed on the wall side, has an actuator insertion hole, and the contacts are switched in response to the movement of an internal operating 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 operating rod inside the switch body moves to switch the contacts.

In such safety switches, the actuator may become misaligned with respect to the actuator insertion hole due to door rattling or misalignment of the door itself, which may result in the actuator being unable to be smoothly inserted into the actuator insertion hole when the door is closed. Therefore, various measures have been taken to prevent such situations from occurring.

For example, in the actuator described in JP 2017-91877 A, the operation key (2) is supported on the base (3) so as to be able to swing, and the operation key (2) is returned to its reference position by the biasing force of the torsion coil spring (41). Therefore, even if the door rattles significantly, the operation key (2) swings when inserted, so that the operation key (2) is inserted into the key insertion port (103, 104) of the switch body (see paragraphs [0037], [0038], [0044], Fig. 1, Fig. 13 to Fig. 15 of the same publication).

In the key switch described in JP 8-138500 A, the key body (9) of the operation key (3) is slidably mounted on the support shaft (12) of the holder (8), and the key body (9) is arranged in a neutral sliding position by the biasing force of the elastic body (13). Therefore, even if an assembly error or misalignment occurs in the operation key (3) and the switch body (2), the operation key (3) slides when inserted, so that the operation key (3) is inserted into the key hole (6) of the switch body (2) (see paragraphs [0009] and [0020] and Figures 1 to 3 of the same publication).

In the driver for a safety switch described in JP 11-317132 A, the base (3) of the key (2) is attached to the holder (1) via a circular PTFE slide bearing (or roller bearing) (9) so that it can slide, and the key (2) is biased to a central position by a spring (10). By displacing the base (3) of the key (2) along the mounting surface of the slide bearing (9), misalignment between the driver and the insertion slot of the safety switch is corrected (see claim 1, paragraphs [0011] and [0012], and figures 1, 3, and 4 of the same publication).

In the device described in JP 2017-91877 A, when there is a positional deviation between the operation key (2) and the key insertion port (103, 104) of the switch body (100), the operation key (2) is adapted to swing when inserted into the key insertion port (103, 104) to absorb the positional deviation. This allows for a positional deviation in the swing direction of the operation key (2) (i.e., within the swing plane), but does not allow for a positional deviation in a direction intersecting (for example, perpendicular to) the swing direction.

In the device described in JP 8-138500 A, when there is a misalignment between the key body (9) of the operation key (3) and the key hole (6) of the switch body (2), the key body (9) slides when inserted into the key hole (6) to absorb the misalignment. This allows for a misalignment in the sliding direction of the key body (9) (i.e., within the sliding plane), but does not allow for a misalignment in a direction intersecting (for example, perpendicular to) the sliding direction.

In contrast, in the device described in JP 11-317132 A, when there is a misalignment between the key (2) and the insertion slot of the safety switch, the key (2) moves along the mounting surface of the slide bearing (9) when inserted into the insertion slot, absorbing the misalignment, and therefore can accommodate misalignments in any direction.

However, when the door is closed with a misalignment between the key (2) and the safety switch insertion slot, an excessive impact load due to the inertia of the door acts on the base (3) of the key (2), which acts directly on the PTFE slide bearing, causing the PTFE slide bearing to break and resulting in durability problems. JP 11-317132 A describes that a roller bearing may be used instead of the PTFE slide bearing, but 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, so while it can accommodate misalignment in the rolling direction, it cannot accommodate misalignment in a direction intersecting (for example perpendicular) the rolling direction.

The present invention was made in consideration of the above-mentioned conventional situation, and the problem that the present invention aims to solve is to provide an actuator unit and a safety switch equipped with the same that can not only absorb misalignment with respect to the actuator insertion hole in any direction intersecting the insertion direction, but also improve durability and smoothly absorb misalignment.

The actuator unit according to the present invention comprises an actuator having a tip portion that can be inserted into an actuator insertion hole, and a support portion that supports the base end portion of the actuator so that it can move in a second direction that intersects with a first direction that is the insertion direction of the actuator into the actuator insertion hole. The support portion has a ball and a holding portion that holds the ball so that it can rotate, is provided separately from the base end portion of the actuator, and is movable in the second direction. Any 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 portion of the actuator with respect to the holding portion in the second direction.

According to the present invention, the base end of the actuator is supported by a support having a rotatable ball and a holder that holds the ball and is movable in a second direction, which is a direction in which the actuator is inserted. The positional deviation between the tip of the actuator and the actuator insertion hole is absorbed by the movement of the base end of the actuator and the holder in the second direction. Therefore, the positional deviation with respect to the actuator insertion hole can be absorbed in any direction that intersects with the insertion direction. Moreover, according to the present invention, since the base end of the actuator is supported by a support having a rotatable ball, even if an excessive thrust load acts on the base end of the actuator due to an excessive load acting on the tip of the actuator when a positional deviation occurs with respect to the actuator insertion hole, the base end of the actuator can be reliably supported by the ball of the support, thereby improving the durability of the actuator unit. In addition, since rolling friction is much smaller than sliding friction, the use of balls can reduce the coefficient of friction compared to the use of slide bearings, which allows the actuator to move smoothly and further improves durability.

Furthermore, according to the present invention, the holding portion that holds the ball rotatably and is movable in the second direction is provided separately from the base end of the actuator, so that when the tip end of the actuator is misaligned with respect to the actuator insertion hole when the actuator is inserted, the holding portion moves in the second direction without being constrained by the base end of the actuator while allowing the ball to rotate. This allows the base end of the actuator to move smoothly in the second direction, making it possible to smoothly absorb the misalignment.

In the present invention, when the positional deviation between the tip of the actuator and the actuator insertion hole is δ, the amount of movement of the holding part in the second direction is h, and the amount of relative movement of the base end of the actuator with respect to the holding part in the second direction is b, the relationship δ = h + b holds.

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

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

In the present invention, the actuator extends between a distal end and a proximal end, the proximal end and the support are housed in a case, and the case has an opening that allows movement of the actuator in a second direction.

In the present invention, the tip has a tapered surface or a convex arc surface. In this case, when the tip comes into contact with the edge of the opening of the actuator insertion hole due to misalignment, the base end of the actuator can move smoothly to the side that absorbs the misalignment.

In the present invention, the tip of the actuator has a locking hole, and the locking hole is adapted to be locked to a locking member inside the switch body, which has an actuator insertion hole.

In the present invention, the actuator has a shaft portion extending between the tip end and the base end, and a step is formed between the shaft portion and the tip end, and the step is adapted to be engaged with a locking member inside the switch body having an actuator insertion hole.

The safety switch according to the present invention comprises an actuator unit according to the present invention and a switch body having an actuator insertion hole.

As described above, according to the present invention, it is possible to absorb misalignment between the tip of the actuator and the actuator insertion hole in any direction intersecting the insertion direction. Moreover, according to the present invention, even if an excessive thrust load acts on the actuator due to an excessive load acting on the tip of the actuator when misalignment occurs, the base end of the actuator can be reliably supported by the ball of the support portion, improving the durability of the actuator unit. Furthermore, according to the present invention, the base end of the actuator can move smoothly in the second direction, making it possible to smoothly absorb misalignment.

1 is an overall perspective view of a safety switch including an actuator unit and a switch main body according to an embodiment of the present invention, as viewed from the front side; FIG. 2 is an overall perspective view of the safety switch (FIG. 1) as viewed from the rear side. FIG. 2 is a front view of the safety switch (FIG. 1); FIG. 2 is a plan view of the safety switch (FIG. 1); FIG. 2 is a vertical cross-sectional view of the actuator unit (FIG. 1). FIG. 6 is a view of the actuator unit (FIG. 5) as viewed obliquely from above on the front side. FIG. 6 is a view of the actuator unit (FIG. 5) seen obliquely from above. 6 is a view of the actuator unit (FIG. 5) with the actuator removed, seen obliquely from above on the front side. FIG. FIG. 6 is a diagram showing the actuator unit (FIG. 5) with the actuator and packing removed. FIG. 10 is a cross-sectional view taken along line X-X of FIG. 10 is a cross-sectional view taken along line XI-XI of FIG. 9 . FIG. 12 is a view of the actuator unit (FIG. 11) seen obliquely from behind. FIG. 12 is an overall perspective view of a ball bearing structure including balls and a retainer in the actuator unit (FIG. 11). FIG. 6 is a schematic diagram of the actuator unit (FIG. 5). 15 is a schematic diagram showing a state after the actuator of the actuator unit (FIG. 14) has moved when the actuator is misaligned with respect to an actuator insertion hole of a switch body; FIG. 16A and 16B are diagrams each showing a further simplified version of FIG. 15, in which (a) shows a state before the actuator is moved, and (b) shows a state after the actuator is moved. 4 is a diagram showing a state in which the actuator unit is not misaligned with respect to the actuator insertion hole of the switch body in the safety switch (FIG. 1); FIG. FIG. 2 is a time-series diagram showing the movement of the actuator in the safety switch (FIG. 1) when the actuator unit is misaligned with the actuator insertion hole of the switch body, showing the state before the actuator is inserted. This is a time-series diagram showing the operation of the actuator when it is inserted into the safety switch (Figure 1) when the actuator unit is misaligned with the actuator insertion hole of the switch body, and shows the state of the actuator midway through insertion. This is a time-series diagram showing the operation of the actuator when it is inserted into the safety switch (Figure 1) when the actuator unit is misaligned with the actuator insertion hole of the switch body, and shows the state after the actuator is inserted. FIG. 21 is a schematic cross-sectional view taken along line XXI-XXI of FIG. 20 . In a safety switch including an actuator unit and a switch body according to a modified example of the present invention, the actuator unit is misaligned with respect to the actuator insertion hole of the switch body, and a state before the actuator is inserted is shown. This shows the safety switch (FIG. 22) in a state after the actuator has been inserted, and corresponds to FIG. 21 of the previous embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
Figures 1 to 4 are diagrams for explaining an actuator unit according to one embodiment of the present invention and a safety switch equipped with the same, and each diagram shows the appearance of the safety switch, with Figures 1 and 2 being oblique views of the safety switch, Figure 3 being a front view, and Figure 4 being a plan view.

As shown in Figures 1 to 4, the safety switch 1 according to this embodiment includes a switch body 2 that is attached, for example, to a wall or a fixed door (not shown), and an actuator unit 3 that is attached, for example, to a sliding movable door (not shown) and is provided so as to be insertable and removable from the switch body 2. In each figure, arrow A indicates the insertion direction (first direction) of the actuator unit 3.

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

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 accommodates the base end side end portion (described later) of the actuator 3A. The tip portion 30 is, for example, plate-shaped (i.e., rectangular in cross section), and each corner on the tip side is formed with a flat inclined surface 30t by chamfering, and the tip side portion has a tapered surface that gradually tapers toward the tip. Note that a rounded surface (i.e., a convex arc-shaped surface) may be formed instead of the inclined surface, or the entire tip side portion may form a convex arc-shaped surface. The tip portion 30 has, for example, a rectangular locking hole 30b that penetrates the tip portion 30 in the thickness direction. In FIG. 4, a dashed line 3C _L indicates the center line of the actuator 3A in the longitudinal direction, and in this example, the center line 3C _L is shown to coincide with the center line 2C _L of the actuator insertion hole 20 of the switch body 2.

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

Next, the details of the base end of the actuator 3A and the support part that supports it will be described with reference to Figures 5 to 13. Figures 5 to 9 show the longitudinal section of the actuator unit 3, Figures 10 to 12 show the transverse section, and Figure 13 shows the overall configuration of the support part. Note that of the cross-sectional views, only Figure 5 shows the cross section by hatching, and hatching is omitted in the other figures.

As shown in Figures 5 to 9, the base end 31 of the actuator 3A is composed of a generally diamond-shaped plate-like portion extending radially outward (see Figure 1), and a screw hole (female thread) 31c extending axially is formed in the boss portion 31C at the center. Meanwhile, a screw 34 extending axially is arranged inside the case 32, and the shaft portion (male thread) 34a of the screw 34 is screwed into and fixed to the screw hole 31c of the boss portion 31C. 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, 35B' that are arranged at an axial interval 35C on the base end side and each protrude radially outward. The flange portion 35B is arranged on the most base end side.

The shaft 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 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 arranged in the opening 32a, and a clearance that allows the flange member 35 to move in the radial direction is formed between the opening 32a and the flange member 35. The tip 35A of the flange member 35 is arranged in a recess 31d formed in the base end 31 of the actuator 3A. A packing 36 made of, for example, rubber is provided in the recess 31d, and one end of the packing 36 is fixed to the tip 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 periphery of the opening 32a formed in the wall portion 32A of the case 32, and is slidable in any radial direction of the opening 32a on the outer surface 32c of the wall portion 32A.

The actuator 3A, the screw 34, the flange member 35, the packing 36 and the seal member 37 are integrally configured as a whole, and therefore the flange portion 35B on the most proximal side of the flange member 35 essentially constitutes the proximal end of the actuator 3A. Between the flange portion 35B on the most proximal side of the flange member 35 and the cover body 33, a support portion 4 is provided separately from the flange portion 35B on the most proximal side (i.e., the proximal end of the actuator 3A) and supports the flange portion 35B slidably in any radial direction. The support portion 4 has a plurality of balls 40 and is composed of a ball bearing structure movable in the direction of arrow B (second direction) intersecting (preferably perpendicular to) the direction of arrow A (first direction) which is the insertion direction of the actuator 3A, and supports the proximal end portion 35B of the actuator 3A movably in the direction of arrow B (details will be described later). The direction of arrow B is not limited to the plane of FIG. 5, but includes any direction that intersects (preferably perpendicular to) the direction of arrow A, that is, any radial direction that intersects (preferably perpendicular to) the axial direction.

In the internal space 32C of the case 32, there are provided torsion coil springs (first elastic support members) 38, 38' that 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 flange portions 35B, 35B' of the flange member 35, and are made of, for example, high-tensile steel wire such as piano wire, other steel wires, metal wires, etc.

As shown in Fig. 10, which is a cross section taken along line XX in Fig. 9, the torsion coil spring 38 is made up of a pair of left and right torsion coil springs 38 ₁ , 38 ₂ , and each of the torsion coil springs 38 ₁ , 38 ₂ is attached to a columnar post 39 ₁ , 39 ₂ extending from the wall surface of the case 32. One arm of each of the torsion coil springs 38 ₁ , 38 ₂ is engaged with the upper inner wall surface of the case 32, and the other arm elastically abuts against the outer circumferential surface of the flange member 35 so as to sandwich the springs from the left and right. Similarly, the torsion coil spring 38 ' is made up of a pair of left and right torsion coil springs 38 ₁ ', 38 ₂ ', and each of the torsion coil springs 38 ₁ ', 38 ₂ ' is attached to a post 39 ₁ ', 39 ₂ ' extending from the wall surface of the case 32, respectively. One arm of each of the torsion coil springs 38 ₁ ', 38 ₂ ' is engaged with the lower inner wall surface of the case 32, and the other arm elastically abuts against the outer circumferential surface of the flange member 35 so as to sandwich it from the left and right.

With this configuration, flange member 35 (and therefore actuator 3A) is elastically supported from the outer periphery, and no matter which radial direction flange member 35 moves in (i.e., the direction of arrow B), the flange member 35 (and therefore actuator 3A) returns to its original position due to the action of elastic repulsive force accompanying elastic deformation of the arms of torsion coil springs 38 ₁ , 38 ₂ , 38 ₁ ', 38 ₂ '. Thus, torsion coil springs 38 ₁ , 38 ₂ , 38 ₁ ', 38 ₂ ' have an automatic centering function with respect to actuator 3A.

As shown in FIG. 9 and its cross section along line XI-XI in FIG. 11, as well as in FIGS. 12 and 13, the support portion 4 has a plurality of balls (i.e., steel balls) 40 (six in this example) made of, for example, steel that can abut against the side surface 35d of the flange portion 35B, and a retainer (holding portion) 41 made of, for example, resin for supporting each ball 40 so that it can rotate freely. Each ball 40 is provided so that it can also abut against the inner surface of the lid body 33. Note that, for convenience of illustration, in FIGS. 5 to 8, a gap is formed between each ball 40 and the side surface 35d of the flange portion 35B, but it is preferable that each ball 40 abuts against the side surface 35d of the flange portion 35B as shown in FIG. 9.

The retainer 41 is a roughly ring-shaped member provided separately from the flange portion 35B on the most proximal side of the flange member 35 (i.e., the proximal end portion of the actuator 3A), and has a plurality of cylindrical retaining holes 41a (six in this example) that support each ball 40 so that it can rotate freely. Each retaining hole 41a is preferably arranged at equal intervals on the circumference. The retainer 41 has a plurality of plate-shaped arm-shaped members (second elastic support members) 42 (three in this example) that extend into the internal space of the retainer 41 and can act as a resin leaf spring, with one end of each arm-shaped member 42 fixed to the ring-shaped portion on the outer periphery of the retainer 41 and the other end (free end) arranged in the center of the retainer 41. The retainer 41 also has multiple (three in this example) compression springs (second elastic support members) 43 arranged in the internal space of the retainer 41, one end of each compression spring 43 being pressed against the ring-shaped portion on the outer periphery of the retainer 41, and the other end being disposed in the center of the retainer 41 and being pressed against the other end of the corresponding arm-shaped member 42. As a result, the other end of each arm-shaped member 42 is elastically abutted against the outer periphery of the screw 34.

With this configuration, the retainer 41 is elastically supported from the inner periphery, and no matter which direction the retainer 41 moves in the radial direction, the elastic repulsive force caused by the elastic deformation of each arm-shaped member 42 and each compression spring 43 causes the retainer 41 to return to its original position before the movement. Therefore, each arm-shaped member 42 and each compression spring 43 has an automatic centering function with respect to the retainer 41.

Next, the effects of this embodiment will be described using Figures 14 to 21 while also referring to Figures 1 to 4. Note that Figures 14 to 16 are schematic diagrams showing a simplified version of Figure 5, and Figures 17 to 21 are diagrams showing the operation of the actuator when it is inserted in time series.

When the movable door is moved in the closing direction from the state shown in Fig. 1 to Fig. 4, the actuator 3A of the actuator unit 3 moves in the direction of the arrow A, and as shown in Fig. 17 and Fig. 21, the actuator 3A is inserted into the switch body 2 through the actuator insertion hole 20 of the switch body 2. During this insertion, the center line 3C _L of the actuator 3A coincides with the center line 2C _L of the actuator insertion hole 20 of the switch body 2 (see Fig. 4 and Fig. 17), so that the tip 30 of the actuator 3A is smoothly inserted into the switch body 2 without interfering with the tapered surface 20a of the actuator insertion hole 20. After the actuator 3A is inserted, the locking hole 30b of the tip 30 of the actuator 3A is locked by the locking member SR inside the switch body 2 as shown in Fig. 21, and 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 operation of a machine such as a robot is started.

18, assume that the center line 3C _L of the actuator 3A is misaligned with the center line 2C _L of the actuator insertion hole 20 of the switch body 2, and the amount of misalignment (misalignment) at that time is δ. Here, take as an example a case in which the center line 3C _L is misaligned downward from the center line 2C _L by a distance δ.

When the movable door is moved in the closing direction from this state, the actuator 3A of the actuator unit 3 moves in the direction of the arrow A, and as shown in FIG. 19, the tip 30 of the actuator 3A abuts against 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 against the tapered surface 20a, so that while the movable door is closed, the inclined surface 30t of the tip 30 slides along the tapered surface 20a and attempts to move diagonally upward as shown. At this time, the actuator 3A moves forward (leftward in FIG. 19) together with the base 3B, and moves relative to the base 3B in the direction of the arrow B, which intersects (preferably perpendicular to) the direction of the arrow A (see FIG. 20).

As described above, the actuator 3A is integral with the screw 34, flange member 35, packing 36, and sealing member 37. Therefore, when the actuator 3A moves in the direction of arrow B, the actuator 3A, screw 34, flange member 35, packing 36, and sealing member 37 move together (therefore, the sealing member 37 slides on the outer surface 32c of the wall portion 32A of the case 32).

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

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 in the center (or approximately in the center) of the opening 32a of the case 32, and is elastically supported in the center of the opening 32a by the respective torsion coil springs 38, 38'. In addition, the retainer 41 of the support portion 4 is elastically supported concentrically (or approximately concentrically) with the actuator 3A by the respective compression springs 43.

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 35B on the most proximal end side of the flange member 35 that is integral with the actuator 3A (i.e., the proximal end portion of 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 cover body 33.

When the actuator 3A starts moving in the direction of arrow B from this state, as shown in FIG. 15, the flange portion 35B moves in the same direction together with the actuator 3A, and the flange portion 35B causes the ball 40 to roll to the right in the figure (i.e., in the direction of arrow B). During this rolling motion, the ball 40 rolls on the lid 33, but 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 restrained by the flange portion 35B. At this time, the entire support portion 4 including the retainer 41 and the ball 41 moves, so the flange portion 35B also moves in the direction of arrow B. In addition, 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 rolls moves in the direction of arrow B. This movement of the flange portion 35B is a relative movement with respect to the retainer 41.

In this way, when the actuator 3A moves in the direction of arrow B, the amount of movement of the flange portion 35B, which moves with the actuator 3A, is the amount of movement caused by the movement of the retainer 41 (and therefore the support portion 4) in the direction of arrow B plus the amount of movement caused by the flange portion 35B moving relative to the retainer 41. Then, when the total amount of movement of the flange portion 35B becomes equal to the positional deviation δ of the actuator 3A, the positional deviation 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 member SR inside the switch body 2 locks the locking hole 30b of the tip portion 30 of the actuator 3A, locking the actuator 3A (see FIG. 21).

Here, Fig. 16(a) shows the state of actuator 3A before it moves, and Fig. 16(b) shows the state of actuator 3A after it moves. In each figure, the contact points between ball 40 and flange 35B and lid 33 are indicated by black circles, and the contact points are connected by line segments d, with d being the diameter of ball 40 (radius r). Also, open triangles indicate the positions on flange 35B and lid 33 that correspond to the black circles.

In FIG. 16B, if the amount of movement of the ball 40 relative to the lid 33 caused by the ball 40 rolling on the lid 33 is _h1 and the rotation angle of the ball 40 at this time is θ, then:
h ₁ =rθ ... (1)
If the amount of movement of the retainer 41 due to the rolling motion of the ball 40 is _h2 , then
_h2 = _h1 ...(2)
In addition, when the ball 40 rotates about its axis during its rolling motion, the amount of movement of the flange portion 35 with which the ball 40 rolls and comes into contact is denoted by b,
b = rθ ... (3)
From equations (1) to (3),
b = _h2 ... (4)
The total movement amount δ of the actuator 3A is given by
δ=h ₂ +b=2h ₂ (∵(4) formula)
where _h2 is replaced by h,
δ=2h
∴h=δ/2…(5)
It becomes.
Equation (5) indicates that when there is a positional deviation in actuator 3A, if retainer 41 moves by half the distance, the positional deviation can be absorbed. Note that Fig. 16 shows an example where _h1 = _h2 = 2.5 (mm), b = 2.5 (mm), and δ = 5.0 (mm).

In summary, the positional deviation 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 of the actuator 3A, in the direction of arrow B relative to the retainer 41, and the positional deviation δ satisfies the relational expression δ = h + b, where the amount of movement of the retainer 41 in the direction of arrow B is h and the amount of movement of the flange portion 35B in the direction of arrow B relative to the retainer 41 is b. Furthermore, if there is no slippage between the ball 40 and the flange portion 35B and the cover 33, h = b, and therefore the relational expression δ = 2h holds.

In this way, according to this embodiment, the base end 35B of the actuator 3A is supported by the support part 4, which is provided with a rotatable ball 40 and a retainer 41 that holds the ball 40 and is separate from the base end 35B, so that the base end 35B can move freely in the direction of arrow B, which intersects with the direction of arrow A, which is the insertion direction of the actuator 3A. Also, any misalignment 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 35B with respect to the retainer 41 in the direction of arrow B. Therefore, any misalignment with respect to the actuator insertion hole 20 can be absorbed in any direction intersecting with the insertion direction.

Moreover, according to this embodiment, the base end 35B of the actuator 3A is supported by the support 4 having the rotatable balls 40. Even if an excessive thrust load acts on the base end 35B of the actuator 3A due to an excessive load acting on the tip 30 of the actuator 3A when the actuator is misaligned with the actuator insertion hole 20, the base end 35B of the actuator 3A can be reliably supported by the balls 40 of the support 4, thereby improving the durability of the actuator unit 3. In addition, because rolling friction is much smaller than sliding friction, the use of the balls 40 can reduce the friction coefficient compared to when a slide bearing is used, thereby realizing smoother movement of the actuator 3A and further improving durability.

Furthermore, according to this embodiment, the retainer 41, which holds the ball 40 rotatably and is movable in the direction of arrow B, is provided separately from the base end 35B of the actuator 3A. Therefore, if the tip 30 of the actuator 3A is misaligned with respect to the actuator insertion hole 20 when the actuator 3A is inserted, the retainer 41 moves in the direction of arrow B without being constrained by the base end 35B of the actuator 3A while allowing the ball 40 to rotate. This allows the base end 35B of the actuator 3A to move smoothly in the direction of arrow B, making it possible to smoothly absorb the misalignment.

Furthermore, when the tip portion 30 of the actuator 3A is inserted into the switch body 2, the actuator 3A moves upward relative to the base portion 3B (see FIG. 20), and at this time, the base end portion 35B of the actuator 3A also moves upward, elastically deforming the upper torsion coil springs _38-1 and _38-2 in FIG. 10 upward. Therefore, at this time, an elastic repulsive force caused by the elastic deformation of the torsion coil springs _38-1 and _38-2 acts downward on the outer circumferential surface of the base end portion 35B of the actuator 3A.

Therefore, when the movable door is opened, as the tip portion 30 of the actuator 3A moves away from the actuator insertion hole 20 of the switch body 2 as the movable door moves, the elastic repulsive force of the torsion coil springs _38-1 , _38-2 acting on the base end portion 35B of the actuator 3A moves the actuator 3A downward, returning it to the state before insertion.

In the above embodiment, an example has been described in which actuator 3A is misaligned downward relative to actuator insertion hole 20, and when the misalignment is absorbed, base end 35B of actuator _3A elastically deforms upper torsion coil springs _38-1 , 38-2 upward. In the case of an upward misalignment, base end 35B abuts against lower torsion coil springs _38-1 ', _38-2 ', elastically deforming them downward, and in the case of a left/right misalignment, base end 35B abuts against torsion coil springs _38-1 , _38-2 ' or _38-2 , _38-1 ', elastically deforming these torsion coil springs left/right.

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

In the above embodiment, the torsion coil springs 38, 38' are used as the first elastic support member, and the compression coil spring 43 is used as the second elastic support member, but the application of the present invention is not limited to these. Elastic support members made of other springs or various elastic bodies may be used.

In the actuator unit 2 according to the embodiment, as shown in Figs. 1 to 4, protrusions 30p, 30p' protruding toward the case 32 are provided at the upper and lower ends of the back surface of the base end 31 of the actuator 3A, and a pair of left and right protrusions 32p, 32p' protruding toward the actuator 3A are provided at the upper and lower ends of the outer surface 32c of the case 32. Each protrusion 32p is disposed at a distance on both the left and right sides of the protrusion 30p, and each protrusion 32p' is disposed at a distance on both the left and right sides of the protrusion 30p'. These protrusions are intended to restrict the actuator 3A from rotating around the center line _3CL during use, and also to allow the actuator 3A to rotate within the range restricted by the protrusions 32p, 32p'. As a result, even if there is some rotational misalignment of the tip portion 30 of the actuator 3A around the center line _3CL relative to the actuator insertion hole 20 (i.e., misalignment due to the tip portion 30 rotating somewhat circumferentially around the center line _3CL ), the actuator 3A can absorb the misalignment by rotating around the center line 3CL.

<Modification>
In the above embodiment, the tip 30 of the actuator 3A is plate-shaped (i.e. rectangular in cross section), but the application of the present invention is not limited to this. Figures 22 and 23 show a safety switch equipped with an actuator unit and a switch body according to a modified example of the present invention. In these figures, the same reference numerals as those in the above embodiment indicate the same or corresponding parts.

22, the tip 30 of the actuator 3A is, for example, a hemispherical protrusion, and has a convex arc surface 30r arranged on the tip side and a flat surface 30c arranged on the rear end side, and the tip of the shaft 31J, for example, a cylindrical shaft extending in the axial direction, is integrally connected to the flat surface 30c. The shaft 31J is a member with a smaller diameter than the tip 30, and the flat surface 30c forms a step with respect to the tip of the shaft 31J. The base end (not shown) of the actuator 3A is provided on the other end side of the shaft 31J. That is, the shaft 31J extends between the tip 30 and the base end of the actuator 3A. The actuator insertion hole 20 of the switch body 2 is, for example, a circular tapered hole penetrating the wall of the switch body 2, and gradually becomes smaller in diameter from the outer surface of the wall 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 previous embodiment, and the configuration of the support portion provided separately from the base end of the actuator 3A is also the same as that of the previous embodiment.

Figure 22 shows the state before the actuator 3A is inserted when the tip 30 of the actuator 3A is displaced downward δ relative 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 the arrow A, and the convex arc-shaped surface 30r of the tip 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 30 slides along the tapered surface 20a while attempting to move obliquely upward in the figure. At this time, in addition to a pressing force in the opposite direction to the arrow A direction, a pressing force in the direction of the arrow B that intersects (preferably perpendicular to) the arrow A direction acts on the actuator 3A.

As a result, as explained in the embodiment with reference to Figures 14 to 16, the base end of the actuator 3A causes the ball of the support part to roll and rotate, absorbing the positional deviation δ of the actuator 3A. When the actuator 3A is inserted into the actuator insertion hole 20, as shown in Figure 23, the locking member SR inside the switch body 2 locks the flat surface 30c that forms the step between the tip part 30 and the shaft part 31J of the actuator 3A, thereby locking the actuator 3A.

In the above embodiment, protrusions 30p, 30p', 32p, and 32p' are provided to restrict rotation of actuator 3A around center line _3CL during use. However, in this modified example, since the cross-sectional shape of tip portion 30 and shaft portion 31J of actuator 3A is circular, it is not necessary to provide such protrusions.

The above-described embodiments and modifications are to be considered in all respects as merely illustrative of the present invention, and not restrictive. Those skilled in the art to which the present invention pertains will be able to construct various modifications and other embodiments incorporating the principles of the present invention without departing from the spirit and essential characteristics of the present invention, even if not expressly described herein, when taking into account the teachings set forth above.

The present invention is useful for an actuator unit and a safety switch equipped with the same.

1: Safety switch

2: Switch body 20: Actuator insertion hole

3: Actuator unit 3A: Actuator 30: Tip portion 30b: Locking hole 30t: Tapered surface 30r: Convex arc surface 31J: Shaft portion 32: Case 32a: Opening 35B: Flange portion on the most proximal end side (proximal end portion of the actuator)
38, 38': Torsion coil spring (first elastic support member)

4: Support part 40: Ball 41: Retainer (holding part)
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: A direction intersecting the actuator insertion direction (second direction)

δ: Positional deviation h: Displacement of the retainer b: Displacement of the actuator relative to the retainer

JP 2017-91877 A (see paragraphs [0037], [0038], [0044], FIG. 1, and FIG. 13 to FIG. 15) JP-A-8-138500 (see paragraphs [0009] and [0020], and Figs. 1 to 3) JP-A-11-317132 (see claim 1, paragraphs [0011] and [0012], Figs. 1, 3, and 4)

Claims (9)

An actuator unit comprising:
an actuator having a tip portion that can be inserted into the actuator insertion hole;
a support portion that supports a base end side end portion of the actuator so as to be movable in a second direction intersecting a first direction that is an insertion direction of the actuator into the actuator insertion hole,
the support portion has a ball and a holder that holds the ball rotatably, is provided separately from the base end side end portion of the actuator, and is movable in the second direction;
a positional deviation between the tip end 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 base end side end of the actuator with respect to the holding portion in the second direction.
1. An actuator unit comprising: In claim 1,
Let δ be a positional deviation between the tip end of the actuator and the actuator insertion hole, h be a movement amount of the holding portion in the second direction, and b be a relative movement amount of the base end side end of the actuator with respect to the holding portion in the second direction,
δ=h+b
The following relation holds true:
1. An actuator unit comprising: In claim 1,
The actuator is provided with a first elastic support member that elastically supports the actuator in the second direction.
1. An actuator unit comprising: In claim 1,
The support portion is provided with a second elastic support member that elastically supports the holding portion in the second direction.
1. An actuator unit comprising: In claim 1,
the actuator extends between the distal end portion and the proximal end portion, the proximal end portion and the support portion are housed in a case, and the case has an opening that allows the actuator to move in the second direction;
1. An actuator unit comprising: In claim 1,
The tip of the actuator has a tapered surface or a convex arc surface.
1. An actuator unit comprising: In claim 1,
The tip of the actuator has a locking hole, and the locking hole is adapted to be locked by a locking member inside a switch body having the actuator insertion hole.
1. An actuator unit comprising: In claim 1,
the actuator has a shaft portion extending between the tip portion and the base end portion, a step is formed between the shaft portion and the tip portion, and the step is adapted to be engaged with a locking member inside a switch body having the actuator insertion hole;
1. An actuator unit comprising: The actuator unit according to claim 1 ;
a switch body having the actuator insertion hole;
With safety switch.