JP2017220964A - Eddy current type speed reduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eddy current type speed reduction device capable of outputting a braking torque of a multi-step with simple structure.SOLUTION: The speed reduction device comprises: a rotor (1); a plurality of permanent magnets (3); a plurality of pole pieces (4); a magnet holding ring (2); a stator (7); a fluid pressure cylinder (20); an actuator (23); and a spacer (22). Each of the permanent magnets (3) is opposite to the rotor (1) with a space. Each of the pole pieces (4) is provided in a space between the rotor (1) and the magnet (3). The stator (7) rotatably supports the ring (2) and holds the pole pieces (4). The cylinder (20) rotates the ring (2) in accordance with the advancing/retracting of a piston rod (21), and switches a braking and a non-braking. The spacer (7) is coupled to a rod (24) of an actuator (23), and limits the advance of the piston rod (21) by coming in contact with a tip (21a) of the advancing spin rod (21).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reduction gear mounted as an auxiliary brake on vehicles such as trucks and buses. In particular, the present invention relates to an eddy current reduction device (hereinafter also simply referred to as “deceleration device”) that uses a permanent magnet (hereinafter also simply referred to as “magnet”) in order to generate a braking force.

  In general, an eddy current type speed reducer includes a cylindrical braking member. The braking member is a rotor fixed to the rotating shaft of the vehicle. Usually, a plurality of magnets are arranged around the rotation axis inside the rotor. The plurality of magnets are held by a magnet holding ring. During braking, magnetic flux from the magnet reaches the rotor through the pole piece, so that an eddy current is generated on the inner peripheral surface of the rotor that rotates integrally with the rotating shaft. As a result, braking torque is generated in the rotor, and the rotational speed of the rotating shaft is reduced.

  Switching between braking and non-braking is usually performed by an air cylinder. The piston rod of the air cylinder advances and retreats by the operation of the air cylinder, and the magnet holding ring rotates around the rotation axis according to the advance and retreat of the piston rod. Thereby, the position of the magnet with respect to the pole piece is changed, and the speed reducer takes a state where a magnetic circuit is generated between the magnet and the rotor and a state where the magnetic circuit is not generated. In a state where a magnetic circuit is generated between the magnet and the rotor, a braking torque is generated. When no magnetic circuit is generated between the magnet and the rotor, no braking torque is generated.

  Here, there are cases where the output of the braking torque in two stages is required for the reduction gear. 2. Description of the Related Art Conventionally, a two-stage air cylinder has been adopted as an air cylinder in order to enable output of two-stage braking torque (for example, Japanese Patent Application Laid-Open No. 2002-101039 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2014-152877). No. (Patent Document 2)). The two-stage air cylinder can control the advancement amount of the piston rod in two stages. That is, in the two-stage air cylinder, it is possible not only to maintain the piston rod in the most advanced state and the most retracted state, but also to maintain the piston rod in a stopped state on the way. When a two-stage air cylinder is employed, the position of the magnet with respect to the pole piece can be switched between a position where the maximum braking torque is generated and a position where a braking torque about half the maximum braking torque is generated during braking.

JP 2002-101439 A JP 2014-152877 A

  As described above, when a two-stage air cylinder is employed, a two-stage braking torque can be output during braking. However, the structure of the two-stage air cylinder is complicated. Therefore, an increase in cost is inevitable. The air cylinder is loaded with a magnetic attractive force between the magnet and the pole piece during switching. Therefore, the air cylinder needs to generate a thrust that exceeds its magnetic attraction. In this regard, in the case of a single-stage air cylinder, the pressure received from one side of the piston can be directly used as the thrust. On the other hand, in the case of a two-stage air cylinder, pressure is received from both sides of the piston, and the differential pressure becomes the thrust. Therefore, the size of the two-stage air cylinder must be larger than that of the first-stage air cylinder for the same required thrust. These disadvantages become significant as the number of air cylinders increases. For this reason, it is extremely difficult to put into practical use a reduction gear that can output braking torque exceeding two stages.

  An object of the present invention is to provide an eddy current type speed reducer capable of outputting multi-stage braking torque including two stages with a simple configuration.

  An eddy current reduction device according to an embodiment of the present invention includes a cylindrical rotor, a plurality of permanent magnets, a plurality of pole pieces, a magnet holding ring, a stator, a fluid pressure cylinder having a piston rod, and a rod. An actuator having a spacer and a spacer. The rotor is fixed to the rotating shaft. The plurality of permanent magnets are opposed to the rotor with a gap, and are arranged around the rotation axis. The plurality of pole pieces are provided in a gap between the rotor and the permanent magnet, and are arranged around the rotation axis. The magnet holding ring holds a permanent magnet. The stator supports the magnet holding ring so as to be rotatable about the rotation axis and holds the pole piece. The fluid pressure cylinder is attached to the stator. The fluid pressure cylinder rotates the magnet holding ring in accordance with the advance and retreat of the piston rod, and switches the position of the permanent magnet with respect to the pole piece. The actuator is attached to the stator. The spacer is connected to the rod of the actuator. The spacer limits the advancement of the piston rod by contacting the tip of the piston rod that advances.

  According to the eddy current type speed reducer of the present invention, a multi-stage braking torque including two stages can be output with a simple configuration.

FIG. 1 is a cross-sectional view schematically showing a main part of the speed reducer according to the first embodiment. FIG. 2 is a longitudinal sectional view schematically showing the reduction gear device of the first embodiment. FIG. 3 is a perspective view showing an arrangement of magnets in the reduction gear according to the first embodiment. FIG. 4A is a cross-sectional view showing a state during non-braking by the speed reducer of the first embodiment. FIG. 4B is a cross-sectional view illustrating a generation state of the magnetic circuit during non-braking by the reduction gear according to the first embodiment. FIG. 5A is a cross-sectional view showing a state during complete braking by the speed reducer of the first embodiment. FIG. 5B is a transverse cross-sectional view illustrating a generation state of the magnetic circuit during complete braking by the speed reducer according to the first embodiment. FIG. 6A is a cross-sectional view illustrating a state during restraint braking by the speed reducer according to the first embodiment. FIG. 6B is a transverse cross-sectional view illustrating a generation state of a magnetic circuit during restraint braking by the speed reducer according to the first embodiment. FIG. 7 is a cross-sectional view showing a modification of the speed reducer of the first embodiment. FIG. 8 is a cross-sectional view schematically showing a main part of the reduction gear according to the second embodiment. FIG. 9 is a cross-sectional view showing a non-braking state by the speed reducer according to the second embodiment. FIG. 10 is a cross-sectional view showing a state at the time of complete braking by the speed reducer according to the second embodiment. FIG. 11 is a cross-sectional view showing a state at the time of restraint braking by the reduction gear according to the second embodiment. FIG. 12 is a cross-sectional view illustrating a state during restraint braking by the reduction gear according to the second embodiment. FIG. 13 is a cross-sectional view showing a modification of the speed reducer of the second embodiment. FIG. 14 is a cross-sectional view schematically showing a main part of the reduction gear device of the third embodiment. FIG. 15 is a cross-sectional view showing a non-braking state by the reduction gear device of the third embodiment. FIG. 16 is a cross-sectional view showing a state during complete braking by the speed reducer of the third embodiment. FIG. 17 is a cross-sectional view illustrating a state during restraint braking by the reduction gear device of the third embodiment. FIG. 18 is a cross-sectional view showing a modification of the reduction gear device of the third embodiment. FIG. 19 is a perspective view illustrating an arrangement of magnets in the reduction gear according to the fourth embodiment. FIG. 20A is a longitudinal cross-sectional view showing a non-braking state by the reduction gear according to the fourth embodiment. FIG. 20B is a cross-sectional view illustrating a state during non-braking with the speed reducer according to the fourth embodiment. FIG. 21A is a longitudinal sectional view showing a state at the time of complete braking by the speed reducer of the fourth embodiment. FIG. 21B is a cross-sectional view showing a state during complete braking by the speed reducer of the fourth embodiment.

  An eddy current reduction device according to an embodiment of the present invention includes a cylindrical rotor, a plurality of permanent magnets, a plurality of pole pieces, a magnet holding ring, a stator, a fluid pressure cylinder having a piston rod, and a rod. An actuator having a spacer and a spacer. The rotor is fixed to the rotating shaft. The plurality of permanent magnets are opposed to the rotor with a gap, and are arranged around the rotation axis. The plurality of pole pieces are provided in a gap between the rotor and the permanent magnet, and are arranged around the rotation axis. The magnet holding ring holds a permanent magnet. The stator supports the magnet holding ring so as to be rotatable about the rotation axis and holds the pole piece. The fluid pressure cylinder is attached to the stator. The fluid pressure cylinder rotates the magnet holding ring in accordance with the advance and retreat of the piston rod, and switches the position of the permanent magnet with respect to the pole piece. The actuator is attached to the stator. The spacer is connected to the rod of the actuator. The spacer limits the advancement of the piston rod by contacting the tip of the piston rod that advances.

  According to the speed reducer of the present embodiment, the piston rod moves forward and backward by the operation of the fluid pressure cylinder, and switching between braking and non-braking is performed. At that time, the actuator is appropriately operated to move the rod of the actuator. If the movement of the piston rod is limited by the movement of the spacer accompanying the movement of the rod of the actuator, the position of the magnet relative to the pole piece can be set only to the non-braking position where no braking torque is generated and the braking position where the maximum braking torque is generated. Instead, it is possible to switch to a position where an intermediate braking torque lower than the maximum braking torque is generated. Therefore, the speed reducer of the present embodiment can output multi-stage braking torque including two stages. In the speed reducer of this embodiment, a simple one-stage cylinder is employed as a fluid pressure cylinder that switches between braking and non-braking. Moreover, the magnetic attractive force between the magnet and the pole piece is not applied to the actuator. For this reason, the actuator does not require a special ability, and a small actuator with a small ability is sufficient. Therefore, the configuration of the speed reducer of this embodiment is simple.

  In a typical example of the speed reducer according to the present embodiment, the plurality of magnets are arranged inside the rotor and face the inner peripheral surface of the rotor with a gap. The arrangement of the magnetic poles (N pole, S pole) of each magnet is in the radial direction with the rotation axis as the center. Arrangement of magnetic poles between adjacent magnets is alternately different. In this case, the plurality of pole pieces are arranged in the gap between the inner peripheral surface of the rotor and the magnet. The arrangement angle around the rotation axis of the plurality of pole pieces coincides with the arrangement angle around the rotation axis of the plurality of magnets. The size of the pole piece alone is almost the same as the size of the magnet alone.

  However, the plurality of magnets may be arranged outside the rotor. In this case, the plurality of magnets face the outer peripheral surface of the rotor with a gap. The plurality of pole pieces are disposed in the gap between the outer peripheral surface of the rotor and the magnet.

  The magnet holding ring holding a plurality of magnets is cylindrical. The magnet holding ring is paired with the rotor and is disposed concentrically with the rotor. The magnet holding ring is supported by the stator so as to be rotatable around the rotation axis. The stator is fixed to the non-rotating part of the vehicle. The plurality of pole pieces are held by the stator. A lever protrudes from the side of the magnet retaining ring. A piston rod of a fluid pressure cylinder is connected to the lever via a link mechanism. If it does so, a piston rod will advance and retreat by the action | operation of a fluid pressure cylinder, and a magnet holding ring will rotate according to the advance and retreat of a piston rod. Thereby, the position of the magnet with respect to the pole piece is changed, and braking and non-braking are switched.

  The type of the fluid pressure cylinder is not particularly limited as long as it is a simple one-stage cylinder. In a typical example, the fluid pressure cylinder is an air cylinder. The fluid pressure cylinder may be a hydraulic cylinder. The single-stage cylinder is a cylinder that can control the advancement amount of the piston rod only in one stage until the stroke end.

  The speed reducer of this embodiment includes the following configuration. The magnet and the magnet holding ring are divided into two rows along the circumferential direction of the rotating shaft. That is, the magnet holding ring is divided into a first row magnet holding ring and a second row magnet holding ring, and the first row and second row magnet holding rings each hold a plurality of magnets. A first row of the magnet holding rings among the magnet holding rings is supported by the stator so as to be rotatable around the rotation axis. A piston rod of a fluid pressure cylinder is connected to the magnet holding ring in the first row. On the other hand, the magnet holding ring in the second row is held by the stator in a state where its own magnet and pole piece are completely overlapped.

  In the case of this configuration, the first row of magnet holding rings is rotated by the operation of the fluid pressure cylinder. Thereby, the position of the magnet of the magnet holding ring of the 1st row changes with respect to the magnet and pole piece of the 2nd row of magnet holding ring, and braking and non-braking are switched. In this case, the size of the pole piece alone is as follows. The length in the circumferential direction around the rotation axis is substantially the same as that of the magnet alone. The axial length along the rotation axis is substantially the same as the sum of the magnets held by the first and second row magnet holding rings.

  The material of the rotor is not particularly limited. However, the material of the surface layer portion of the surface facing the magnet in the rotor is a conductive material. This is to generate an eddy current. Examples of conductive materials include ferromagnetic metal materials (eg, carbon steel, cast iron, etc.), weak magnetic metal materials (eg: ferritic stainless steel, etc.), or non-magnetic metal materials (eg, aluminum alloys, austenitic stainless steel, Copper alloy etc.). In a typical example, the material of the rotor is a ferromagnetic metal material (eg, carbon steel, cast iron, etc.), and a material with high conductivity (eg, aluminum alloy, copper alloy, etc.) on the surface of the rotor facing the magnet. The plating layer is formed.

  The material of the magnet holding ring is a ferromagnetic metal material (eg, carbon steel, cast iron, etc.). This is because a magnetic circuit is generated through the magnet holding ring.

  The material of the spacer is not particularly limited. However, the spacer contacts the tip of the piston rod and restricts the advancement of the piston rod. Therefore, the spacer is required to have durability against repeated contact with the tip of the piston rod. Therefore, a preferable material of the spacer is a metal material (eg, chromium molybdenum steel) or an engineering plastic (eg, polyacetal).

  Here, the speed reducer of the present embodiment takes a state in which the spacer is disposed on the extension of the piston rod and a state in which the spacer is removed from the extension of the piston rod due to the advance / retreat of the rod accompanying the operation of the actuator. Can be. The actuator in this case may be a fluid pressure cylinder or an electric actuator (eg, solenoid, servo motor, etc.).

  The following configuration can be adopted for the reduction gear of the present embodiment. The spacer has a top surface and one step surface. In this case, the speed reducer takes a state in which the top surface is disposed on the extension of the piston rod and a state in which the step surface is disposed on the extension of the piston rod by the advancement / retraction of the rod accompanying the operation of the actuator. Instead of such a configuration, the spacer may have a top surface and a plurality of step surfaces having a linear staircase shape. In this case, the speed reducer takes a state in which the top surface is disposed on the extension of the piston rod and a state in which each step surface is disposed on the extension of the piston rod by the advance and retreat of the rod accompanying the operation of the actuator. . The actuator in these cases is preferably an electric actuator.

  Moreover, the following structures can be employ | adopted for the speed reducer of this embodiment. The spacer has a top surface and one step surface. In this case, the speed reducer takes a state in which the top surface is disposed on the extension of the piston rod and a state in which the step surface is disposed on the extension of the piston rod by rotation of the rod accompanying the operation of the actuator. Instead of such a configuration, the spacer may have a top surface and a plurality of step surfaces having a spiral staircase shape. In this case, the speed reducer has a state in which the top surface is disposed on the extension of the piston rod and a state in which each step surface is disposed on the extension of the piston rod by the rotation of the rod accompanying the operation of the actuator. take. The actuator in these cases is preferably a servo motor.

  Below, the embodiment is explained in full detail about the eddy current type reduction gear device of the present invention.

[First Embodiment]
FIG.1 and FIG.2 is a figure which shows typically the speed reducer of 1st Embodiment. Among these drawings, FIG. 1 is a cross-sectional view of the main part, and FIG. 2 is a vertical cross-sectional view. FIG. 3 is a perspective view showing the arrangement of magnets in the reduction gear. FIG. 4A and FIG. 4B are diagrams showing a state during non-braking by the reduction gear. FIG. 5A and FIG. 5B are diagrams illustrating a state in which the braking force is generated by the speed reducer and the maximum braking torque is generated. 6A and 6B are diagrams illustrating a state in which an intermediate braking torque is generated in one state during braking by the reduction gear. Among these drawings, FIGS. 4A, 5A and 6A are cross-sectional views showing a fluid pressure cylinder for switching between braking and non-braking and the vicinity thereof. 4B, 5B, and 6B are cross-sectional views showing the occurrence of the magnetic circuit. Here, the longitudinal section is a section along the rotation axis. A transverse section is a section perpendicular to the rotation axis.

  As shown in FIGS. 1 to 3, the speed reducer includes a cylindrical rotor 1 and a cylindrical magnet holding ring 2 disposed inside the rotor 1. The rotor 1 corresponds to a braking member to which braking torque is applied. The rotor 1 is fixed to a rotating shaft 10 (eg, propeller shaft, drive shaft, etc.) of the vehicle via a rotor support member 6. Thereby, the rotor 1 rotates integrally with the rotating shaft 10. Radiating fins 1 a are provided on the outer peripheral surface of the rotor 1.

  The magnet holding ring 2 is disposed concentrically with the rotor 1. The magnet holding ring 2 is supported via the stator 7 so as to be rotatable around the rotation shaft 10. The stator 7 is fixed to a non-rotating part 11 (for example, a transmission cover) of the vehicle.

  A plurality of permanent magnets 3 are fixed to the outer peripheral surface of the magnet holding ring 2. The magnet 3 is opposed to the inner peripheral surface 1 b of the rotor 1 with a gap, and is arranged over a circumferential direction centering on the rotation shaft 10. That is, the magnet 3 is held by the magnet holding ring 2 and arranged around the rotation shaft 10. The arrangement of the magnetic poles (N pole and S pole) of each magnet 3 is in the radial direction with the rotary shaft 10 as the center. Arrangement of magnetic poles of magnets 3 adjacent to each other is alternately different (see FIG. 3).

  A plurality of ferromagnetic pole pieces 4 are arranged in the gap between the inner peripheral surface 1 b of the rotor 1 and the magnet 3. The pole pieces 4 are arranged in a circumferential direction around the rotation shaft 10. The arrangement angle of the pole piece 4 around the rotation axis 10 coincides with the arrangement angle of the magnet 3 around the rotation axis 10 (see FIGS. 4B, 5B and 6B). The pole piece 4 is held on both sides by a pole piece holding ring 5 (see FIG. 2). The pole piece holding ring 5 is fixed to the stator 7. That is, the pole piece 4 is held by the stator 7 and arranged around the rotation shaft 10.

  As shown in FIGS. 1 and 2, the lever 2 a protrudes from the side surface of the magnet holding ring 2. The piston rod 21 of the air cylinder 20 is connected to the lever 2a via a link mechanism (not shown). The air cylinder 20 is a single-stage cylinder and corresponds to a fluid pressure cylinder. The air cylinder 20 is attached to a housing 7 a integrated with the stator 7.

  In response to a command from a control device (not shown), the air cylinder 20 operates using compressed air as power. By the operation of the air cylinder 20, the piston rod 21 moves back and forth within the housing 7a. As the piston rod 21 advances and retreats, the magnet holding ring 2 rotates to switch between braking and non-braking.

  In the present embodiment, a rectangular parallelepiped spacer 22 is housed inside the housing 7a. The spacer 22 is connected to a rod 24 of an air cylinder 23 different from the air cylinder 20 used for switching between braking and non-braking described above. The air cylinder 23 is a single-stage cylinder, but has a smaller capacity and size than the air cylinder 20. Hereinafter, for convenience of explanation, the air cylinder 23 connected to the spacer 22 is referred to as an auxiliary air cylinder 23. The auxiliary air cylinder 23 is attached to the housing 7a so that the forward / backward direction of the rod 24 of the auxiliary air cylinder 23 is orthogonal to the forward / backward direction of the piston rod 21 of the air cylinder 20. The auxiliary air cylinder 23 here corresponds to an actuator. The auxiliary air cylinder 23 may be a fluid pressure cylinder such as a hydraulic cylinder. The auxiliary air cylinder 23 may be changed to an electric actuator such as a solenoid.

  The auxiliary air cylinder 23 is actuated by a command from the control device. By the operation of the auxiliary air cylinder 23, the rod 24 advances and retracts, and the spacer 22 advances and retracts within the housing 7a. As a result, the speed reducer takes a state in which the spacer 22 is disposed on the extension of the piston rod 21 and a state in which the spacer 22 is removed from the extension of the piston rod 21.

  When the piston rod 21 advances in a state where the spacer 22 is disposed on the extension of the piston rod 21, the tip 21 a of the piston rod 21 comes into contact with the top surface 22 a of the spacer 22. Such contact between the spacer 22 and the piston rod 21 limits the advancement of the piston rod 21. On the other hand, when the spacer 22 is removed from the extension of the piston rod 21, the piston rod 21 advances to the stroke end without any limitation.

  When switching between braking and non-braking, the piston rod 21 is advanced and retracted by the operation of the air cylinder 20, and the magnet holding ring 2 and the magnet 3 rotate integrally around the rotary shaft 10. Prior to the operation of the air cylinder 20, the auxiliary air cylinder 23 is operated as necessary, so that the rod 24 moves forward and backward, and the spacer 22 moves forward and backward. Thereby, the position of the magnet 3 with respect to the pole piece 4 is as follows.

  At the time of non-braking, as shown in FIG. 4A, the piston rod 21 is placed in the most retracted state. The position of the spacer 22 does not matter. In this case, as shown in FIG. 4B, the pole pieces 4 straddle the adjacent magnets 3 evenly. In this state, no braking torque is generated.

  The magnetic flux from the magnet 3 during non-braking is as follows. As shown in FIG. 4B, the magnetic flux emitted from the north pole of one of the adjacent magnets 3 reaches the south pole of the other magnet 3 after passing through the pole piece 4. The magnetic flux emitted from the N pole of the other magnet 3 reaches the S pole of one magnet 3 through the magnet holding ring 2. That is, no magnetic circuit is generated between the magnet 3 and the rotor 1. Therefore, no braking torque is generated in the rotor 1 that rotates integrally with the rotary shaft 10.

  At the time of braking, for example, as shown in FIG. 5A, the spacer 22 is most retracted and placed at a position away from the extension of the piston rod 21. When the piston rod 21 advances in this state, the piston rod 21 is placed in the most advanced state. At that time, the magnet holding ring 2 rotates about half the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 completely overlaps the magnet 3 as shown in FIG. 5B. In this state, the maximum braking torque is generated. Hereinafter, this state is also referred to as “complete braking”.

  During complete braking, the magnetic flux from the magnet 3 is as follows. As shown in FIG. 5B, the magnetic flux emitted from the north pole of one of the adjacent magnets 3 passes through the pole piece 4 and reaches the rotor 1. The magnetic flux that has reached the rotor 1 reaches the S pole of the other magnet 3 through the pole piece 4. The magnetic flux emitted from the N pole of the other magnet 3 reaches the S pole of one magnet 3 through the magnet holding ring 2. That is, a magnetic circuit including the magnets 3 is formed between the magnets 3 adjacent to each other in the circumferential direction, the magnet holding ring 2, the pole piece 4, and the rotor 1. Such a magnetic circuit is formed by alternately reversing the direction of the magnetic flux over the entire circumferential direction. In this case, the maximum braking torque in the direction opposite to the rotation direction is generated in the rotor 1 that rotates integrally with the rotary shaft 10.

  Further, at the time of braking, for example, as shown in FIG. 6A, the spacer 22 advances most and is placed at a position on the extension of the piston rod 21. When the piston rod 21 advances in this state, the tip 21a of the piston rod 21 contacts the top surface 22a of the spacer 22, and the advancement of the piston rod 21 stops midway. At that time, the magnet holding ring 2 rotates about 1/4 of the arrangement angle of the magnet 3 from the non-braking state. In this case, as shown in FIG. 6B, the pole piece 4 overlaps with one magnet 3 extensively while straddling adjacent magnets 3 unevenly. In this state, an intermediate braking torque lower than the maximum braking torque (about half of the maximum braking torque) is generated. Hereinafter, this state is also referred to as “suppressing braking”.

  At the time of restraint braking, the magnetic flux from the magnet 3 is as follows. As shown in FIG. 6B, most of the magnetic circuit by the magnet 3 is the same as that at the time of complete braking shown in FIG. 5B. However, a part of the magnetic flux from the magnet 3 does not reach the rotor 1 as in the case of non-braking shown in FIG. 4B. Therefore, the magnetic flux reaching the rotor 1 from the magnet 3 is less than that during complete braking. Therefore, the braking torque generated during restraint braking is lower than the maximum braking torque generated during complete braking.

  Thus, according to the speed reducer of the present embodiment, the position of the magnet with respect to the pole piece can be switched not only to the non-braking position and the complete braking position but also to one restraining braking position. Therefore, the speed reducer of the present embodiment can output two levels of braking torque. In the speed reducer of this embodiment, a simple one-stage air cylinder is employed as a fluid pressure cylinder that switches between braking and non-braking. An actuator having a small capacity and size is used as the actuator for moving the spacer. Therefore, the configuration of the speed reducer of this embodiment is simple.

  FIG. 7 is a cross-sectional view showing a modification of the speed reducer of the first embodiment. In the case of the first embodiment shown in FIGS. 1 and 6A, when the tip 21a of the piston rod 21 contacts the top surface 22a of the spacer 22, only the auxiliary air cylinder 23 receives an impact from the air cylinder 20 (piston rod 21). Take it. This is because a gap exists between the back surface of the spacer 22 (the surface opposite to the top surface 22a) and the inner surface of the housing 7a. For this reason, the auxiliary air cylinder 23 may be damaged early.

  Therefore, as shown in FIG. 7, a buffer material 25 may be provided on the back surface of the spacer 22. The buffer material 25 is integral with the spacer 22 and is in contact with the inner surface of the housing 7a. When the rod 24 moves back and forth by the operation of the auxiliary air cylinder 23, the cushioning material 25 slides on the inner surface of the housing 7a. Further, when the tip 21a of the piston rod 21 comes into contact with the top surface 22a of the spacer 22, the cushioning material 25 receives an impact from the air cylinder 20 (piston rod 21). Thereby, damage to the auxiliary air cylinder 23 can be prevented.

  The material of the buffer material 25 is not particularly limited. However, the cushioning material 25 needs to slide smoothly with the inner surface of the housing 7a. Further, the buffer material 25 is required to have durability against repeated impacts. Therefore, a preferable material of the buffer material 25 is a resin or a sintered metal containing the resin.

  In addition, a buffer plate (not shown) such as rubber may be provided on the top surface 22a of the spacer 22 that contacts the tip 21a of the piston rod 21. This is because the shock can be reduced by the buffer plate.

[Second Embodiment]
FIG. 8 is a cross-sectional view schematically showing a main part of the reduction gear according to the second embodiment. FIG. 9 is a diagram illustrating a state during non-braking by the reduction gear. FIG. 10 is a diagram illustrating a state in which the maximum braking torque is generated in one state during braking by the reduction gear. FIG. 11 and FIG. 12 are diagrams showing a state in which braking is performed by the reduction gear and a state in which an intermediate braking torque is generated. 9 to 12 are cross-sectional views showing a fluid pressure cylinder for switching between braking and non-braking and the vicinity thereof. The speed reducer of the second embodiment is based on the configuration of the speed reducer of the first embodiment, and the description of the configuration common to both is omitted as appropriate. The same applies to third to fourth embodiments described later.

  The speed reducer according to the second embodiment is mainly different from the first embodiment in the shape of the spacer. In the present embodiment, the spacer 32 has a top surface 32a and a step surface 32b of one step. The spacer 32 is connected to the rod 34 of the solenoid 33. The solenoid 33 can control the advancement amount of the rod 34 in two stages. The solenoid 33 is smaller in capacity and size than the air cylinder 20 used for switching between braking and non-braking. The solenoid 33 here corresponds to an actuator. As long as the advance amount of the rod 34 can be controlled in two stages, the solenoid 33 may be changed to an electric actuator such as a servo motor.

  The solenoid 33 is actuated by a command from the control device. By actuating the solenoid 33, the rod 34 advances and retracts in two stages, and the spacer 32 advances and retracts in two stages in the housing 7a. Thereby, the speed reducer takes a state where the spacer 32 is disengaged from the extension of the piston rod 21. Further, the speed reducer takes a state in which the top surface 32 a of the spacer 32 is disposed on the extension of the piston rod 21 and a state in which the step surface 32 b of the spacer 32 is disposed on the extension of the piston rod 21.

  When the piston rod 21 advances in a state where the top surface 32 a of the spacer 32 is disposed on the extension of the piston rod 21, the tip 21 a of the piston rod 21 contacts the top surface 32 a of the spacer 32. When the piston rod 21 advances in a state where the step surface 32b of the spacer 32 is disposed on the extension of the piston rod 21, the tip 21a of the piston rod 21 comes into contact with the step surface 32b of the spacer 32. Due to the contact between the spacer 32 and the piston rod 21, the advancement of the piston rod 21 is limited to two stages. On the other hand, in a state where the spacer 32 is removed from the extension of the piston rod 21, the piston rod 21 advances to the stroke end without any limitation.

  When switching between braking and non-braking, the piston rod 21 is advanced and retracted by the operation of the air cylinder 20, and the magnet holding ring 2 and the magnet 3 rotate integrally around the rotary shaft 10. Prior to the operation of the air cylinder 20, the solenoid 34 is operated as necessary, so that the rod 34 is advanced and retracted, and the spacer 32 is advanced and retracted. Thereby, the position of the magnet 3 with respect to the pole piece 4 is as follows.

  During non-braking, as shown in FIG. 9, the piston rod 21 is placed in the most retracted state. The position of the spacer 32 does not matter. In this case, similarly to the first embodiment, the pole pieces 4 evenly straddle the adjacent magnets 3 (see FIG. 4B). In this state, no braking torque is generated.

  At the time of complete braking, as shown in FIG. 10, the spacer 32 is most retracted and placed at a position away from the extension of the piston rod 21. When the piston rod 21 advances in this state, the piston rod 21 is placed in the most advanced state. At that time, similarly to the first embodiment, the magnet holding ring 2 rotates about half the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 completely overlaps with the magnet 3 (see FIG. 5B). In this state, the maximum braking torque is generated.

  At the time of restraint braking, for example, as shown in FIG. 11, the top surface 32 a of the spacer 32 is placed at a position on the extension of the piston rod 21 by the operation of the solenoid 33. When the piston rod 21 advances in this state, the tip 21a of the piston rod 21 comes into contact with the top surface 32a of the spacer 32, and the advancement of the piston rod 21 stops midway. At that time, similarly to the first embodiment, the magnet holding ring 2 rotates about 1/4 of the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 overlaps one of the magnets 3 in a non-uniform manner across the adjacent magnets 3 (see FIG. 6B). In this state, an intermediate braking torque lower than the maximum braking torque (about half of the maximum braking torque) is generated.

  At the time of restraint braking, for example, as shown in FIG. 12, the stepped surface 32 b of the spacer 32 is placed at a position on the extension of the piston rod 21 by the operation of the solenoid 33. When the piston rod 21 advances in this state, the tip 21a of the piston rod 21 comes into contact with the stepped surface 32b of the spacer 32, and the advancement of the piston rod 21 stops midway. At that time, the magnet holding ring 2 rotates about 3/4 of the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 does not completely overlap with the magnet 3, but overlaps the magnet 3 extensively. In this state, an intermediate braking torque lower than the maximum braking torque (about 3/4 of the maximum braking torque) is generated.

  Thus, according to the reduction gear of this embodiment, the position of the magnet with respect to the pole piece can be switched not only to the non-braking position and the complete braking position, but also to the two restraining braking positions. Therefore, the speed reducer of the present embodiment can output three levels of braking torque. In addition, the configuration of the reduction gear according to the present embodiment is simple as in the first embodiment.

  In the speed reducer of the present embodiment, there may be a plurality of stepped surfaces 32b of the spacer 32 in a linear step shape. In this case, the solenoid 33 that advances and retracts the spacer 32 can control the amount of advancement of the rod 34 in multiple stages, which is the total number of the top surface 32 a and the step surface 32 b of the spacer 32. By the operation of the solenoid 33, the rod 34 advances and retracts in multiple stages, and the spacer 32 advances and retracts in multiple stages. Thereby, the speed reducer takes a state where the spacer 32 is disengaged from the extension of the piston rod 21. Further, the speed reducer takes a state in which the top surface 32 a of the spacer 32 is disposed on the extension of the piston rod 21 and a state in which each step surface 32 b of the spacer 32 is disposed on the extension of the piston rod 21.

  According to such a reduction gear, the position of the magnet with respect to the pole piece can be switched to not only the non-braking position and the complete braking position but also three or more restraining braking positions. Therefore, the speed reducer of this embodiment can output four or more multi-stage braking torques.

  FIG. 13 is a cross-sectional view showing a modification of the speed reducer of the second embodiment. In the case of the second embodiment shown in FIGS. 8, 11, and 12, when the tip 21 a of the piston rod 21 contacts the top surface 32 a or the step surface 32 b of the spacer 32, only the solenoid 33 moves to the air cylinder 20 (piston rod 21 ) This is because a gap exists between the back surface of the spacer 32 (the surface opposite to the top surface 32a and the step surface 32b) and the inner surface of the housing 7a. Therefore, the solenoid 33 may be damaged early.

  Therefore, as shown in FIG. 13, a buffer material 35 may be provided on the back surface of the spacer 32. The buffer material 35 is integral with the spacer 32 and is in contact with the inner surface of the housing 7a. When the rod 34 moves forward and backward by the operation of the solenoid 33, the cushioning material 35 slides on the inner surface of the housing 7a. Further, when the tip 21a of the piston rod 21 comes into contact with the top surface 32a or the stepped surface 32b of the spacer 32, the buffer material 35 receives an impact from the air cylinder 20 (piston rod 21). Thereby, damage to the solenoid 33 can be prevented.

  The material of the buffer material 35 is not particularly limited. However, the cushioning material 35 needs to slide smoothly with the inner surface of the housing 7a. Further, the buffer material 35 is required to have durability against repeated impacts. Therefore, a preferable material of the buffer material 35 is a resin or a sintered metal containing the resin.

  In addition, a buffer plate (not shown) such as rubber may be provided on the top surface 32a and the step surface 32b of the spacer 32 that contacts the tip 21a of the piston rod 21. This is because the shock can be reduced by the buffer plate.

[Third Embodiment]
FIG. 14 is a cross-sectional view schematically showing a main part of the reduction gear device of the third embodiment. FIG. 15 is a diagram illustrating a state during non-braking by the reduction gear. FIG. 16 is a diagram illustrating a state in which the maximum braking torque is generated in one state during braking by the reduction gear. FIG. 17 is a diagram illustrating a state in which an intermediate braking torque is generated in one state during braking by the reduction gear. 15 to 17 are cross-sectional views showing a fluid pressure cylinder for switching between braking and non-braking and the vicinity thereof.

  The speed reduction device of the third embodiment is mainly different from the first embodiment in the shape of the spacer and the operation mode of the actuator that moves the spacer. In the present embodiment, the spacer 42 has a top surface 42a and a stepped surface 42b. The spacer 42 is connected to a rod 44 that is a rotating shaft of the servo motor 43. The servo motor 43 is attached to the housing 7a so that the axial direction of the rod 44 of the servo motor 43 is parallel to the forward / backward direction of the piston rod 21 of the air cylinder 20. The servo motor 43 can control the amount of rotation of the rod 44 in two stages of 180 ° pitch. The servo motor 43 is smaller in capacity and size than the air cylinder 20 used for switching between braking and non-braking. The servo motor 43 here corresponds to an actuator.

  The servo motor 43 operates in response to a command from the control device. By the operation of the servo motor 43, the rod 44 rotates in two stages, and the spacer 42 rotates in two stages in the housing 7a. Thereby, the speed reducer takes a state where the top surface 42 a of the spacer 42 is disposed on the extension of the piston rod 21 and a state where the step surface 42 b of the spacer 42 is disposed on the extension of the piston rod 21.

  When the piston rod 21 advances in a state where the top surface 42 a of the spacer 42 is disposed on the extension of the piston rod 21, the tip 21 a of the piston rod 21 contacts the top surface 42 a of the spacer 42. When the piston rod 21 advances in a state where the stepped surface 42b of the spacer 42 is disposed on the extension of the piston rod 21, the tip 21a of the piston rod 21 contacts the stepped surface 42b of the spacer 42. Due to the contact between the spacer 42 and the piston rod 21, the advancement of the piston rod 21 is limited to two stages.

  When switching between braking and non-braking, the piston rod 21 is advanced and retracted by the operation of the air cylinder 20, and the magnet holding ring 2 and the magnet 3 rotate integrally around the rotary shaft 10. Prior to the operation of the air cylinder 20, the servo motor 43 is operated as necessary, so that the rod 44 rotates and the spacer 42 rotates. Thereby, the position of the magnet 3 with respect to the pole piece 4 is as follows.

  At the time of non-braking, as shown in FIG. 15, the piston rod 21 is placed in the most retracted state. The positions of the top surface 42a and the step surface 42b of the spacer 42 are not limited. In this case, similarly to the first embodiment, the pole pieces 4 evenly straddle the adjacent magnets 3 (see FIG. 4B). In this state, no braking torque is generated.

  At the time of complete braking, as shown in FIG. 16, the stepped surface 42 b of the spacer 42 is placed at a position on the extension of the piston rod 21 by the operation of the servo motor 43. When the piston rod 21 advances in this state, the tip 21a of the piston rod 21 contacts the stepped surface 42b of the spacer 42, and the advancement of the piston rod 21 stops midway. At that time, similarly to the first embodiment, the magnet holding ring 2 rotates about half the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 completely overlaps with the magnet 3 (see FIG. 5B). In this state, the maximum braking torque is generated.

  Further, at the time of restraint braking, as shown in FIG. 17, the top surface 42 a of the spacer 42 is placed at a position on the extension of the piston rod 21 by the operation of the servo motor 43. When the piston rod 21 advances in this state, the tip 21a of the piston rod 21 comes into contact with the top surface 42a of the spacer 42, and the advancement of the piston rod 21 stops midway. At that time, similarly to the first embodiment, the magnet holding ring 2 rotates about 1/4 of the arrangement angle of the magnet 3 from the non-braking state. In this case, the pole piece 4 overlaps one of the magnets 3 in a non-uniform manner across the adjacent magnets 3 (see FIG. 6B). In this state, an intermediate braking torque lower than the maximum braking torque (about half of the maximum braking torque) is generated.

  As described above, the speed reducer according to the present embodiment can output two levels of braking torque as in the first embodiment. In addition, the configuration of the reduction gear according to the present embodiment is simple as in the first embodiment.

  In the speed reducer of the present embodiment, a plurality of step surfaces 42b of the spacer 42 may be provided in a spiral staircase shape. In this case, the servo motor 43 that rotates the spacer 42 can control the amount of rotation of the rod 44 in multiple stages with a pitch of “360 ° / (total number of top surfaces 42a and step surfaces 42b of the spacer 42)”. . By the operation of the servo motor 43, the rod 44 rotates in multiple stages and the spacer 42 rotates in multiple stages. Thereby, the speed reducer takes a state in which the top surface 42a of the spacer 42 is disposed on the extension of the piston rod 21 and a state in which each stepped surface 42b of the spacer 42 is disposed on the extension of the piston rod 21. .

  According to such a reduction gear, the position of the magnet with respect to the pole piece can be switched to not only the non-braking position and the complete braking position but also two or more restraining braking positions. Therefore, the speed reducer of the present embodiment can output three or more multistage braking torques.

  FIG. 18 is a cross-sectional view showing a modification of the reduction gear device of the third embodiment. In the case of the third embodiment shown in FIGS. 14, 16 and 17, when the tip 21 a of the piston rod 21 contacts the top surface 42 a or the step surface 42 b of the spacer 42, only the servo motor 43 moves to the air cylinder 20 (piston rod 21) Take the shock from. This is because there is a gap between the back surface of the spacer 42 (the surface opposite to the top surface 42a and the step surface 42b) and the inner surface of the housing 7a. For this reason, the servo motor 43 may be damaged early.

  Therefore, as shown in FIG. 18, a cushioning material 45 may be provided on the back surface of the spacer 42. The cushioning material 45 is integral with the spacer 42 and is in contact with the inner surface of the housing 7a. When the rod 44 is rotated by the operation of the servo motor 43, the cushioning material 45 slides on the inner surface of the housing 7a. Further, when the tip 21a of the piston rod 21 comes into contact with the top surface 42a or the stepped surface 42b of the spacer 42, the cushioning material 45 receives an impact from the air cylinder 20 (piston rod 21). Thereby, damage to the servo motor 43 can be prevented.

  The material of the buffer material 45 is not particularly limited. However, the cushioning material 45 needs to slide smoothly with the inner surface of the housing 7a. Further, the buffer material 45 is required to have durability against repeated impacts. Therefore, a preferable material of the buffer material 45 is a resin or a sintered metal containing the resin.

  In addition, a buffer plate (not shown) such as rubber may be provided on the top surface 42a and the step surface 42b of the spacer 42 that contacts the tip 21a of the piston rod 21. This is because the shock can be reduced by the buffer plate.

[Fourth Embodiment]
FIG. 19 is a perspective view illustrating an arrangement of magnets in the reduction gear according to the fourth embodiment. FIG. 20A and FIG. 20B are diagrams showing a state during non-braking by the reduction gear. FIG. 21A and FIG. 21B are diagrams illustrating a state in which the braking force is generated by the speed reduction device and the maximum braking torque is generated. Of these figures, FIGS. 20A and 21A are longitudinal sectional views showing the occurrence of a magnetic circuit, and FIGS. 20B and 21B are transverse sectional views showing the occurrence of a magnetic circuit.

  When the reduction gear of the fourth embodiment and the reduction gear of the first embodiment are compared, the configurations of the magnet and the magnet holding ring are slightly different. In the present embodiment, the magnet 3 and the magnet holding ring 2 are equally divided into two rows along the circumferential direction of the rotating shaft 10. That is, the magnet holding ring 2 is divided into a first row of magnet holding rings 2A and a second row of magnet holding rings 2B, and the first row and second row of magnet holding rings 2A and 2B are respectively a plurality of magnets 3A and 3B. Hold. The first row of magnets 3A and the magnet holding ring 2A and the second row of magnets 3B and the magnet holding ring 2B are independent of each other with a slight gap. The arrangement of the magnetic poles of the magnets 3A and 3B is the same as in the first embodiment. In the following description, when the magnets 3A and 3B in the first row and the second row are collectively referred to, the reference numeral is also denoted as 3. When the first row and the second row of magnet holding rings 2A and 2B are collectively referred to, the reference numeral is also denoted by 2.

  A plurality of pole pieces 4 are arranged in the gap between the inner peripheral surface 1b of the rotor 1 and the magnets 3A and 3B, as in the first embodiment. Unlike the magnets 3A and 3B and the magnet holding rings 2A and 2B, the pole piece 4 is not divided.

  Similarly to the first embodiment, the first row of magnet holding rings 2A is supported by the stator 7 so as to be rotatable about the rotation shaft 10. A piston rod 21 of an air cylinder 20 that is a fluid pressure cylinder is connected to the magnet holding ring 2A in the first row. On the other hand, the magnet holding ring 2B in the second row is held by the stator 7 in a state where the magnet 3B of the magnet holding ring 2B in the second row and the pole piece 4 are completely overlapped. The arrangement angle of the pole piece 4 around the rotation axis 10 coincides with the arrangement angle of the magnets 3A and 3B around the rotation axis 10.

  As in the first embodiment, when switching between braking and non-braking, the piston rod 21 is advanced and retracted by the operation of the air cylinder 20, and the magnet holding ring 2A and the magnet 3A in the first row are integrated around the rotary shaft 10. Rotate to. Prior to the operation of the air cylinder 20, the auxiliary air cylinder 23 is operated as necessary, so that the rod 24 moves forward and backward, and the spacer 22 moves forward and backward. Thereby, the position of the magnet 3A of the first row with respect to the magnet 3B and the pole piece 4 of the second row is as follows.

  At the time of non-braking, as shown in FIG. 20A, the first row of magnets 3A and the second row of magnets 3B are completely overlapped in the axial direction along the rotation axis 10, and further, the first row and the first row adjacent to each other in the axial direction. The arrangement of the magnetic poles of the two rows of magnets 3A and 3B is alternately different. In this case, the magnetic flux from the magnet 3 is as follows. As shown in FIG. 20A, the magnetic flux emitted from the N pole of one of the magnets 3 in the first and second rows adjacent to each other in the axial direction passes through the pole piece 4 and then the other magnet 3. Reaches the S pole. The magnetic flux emitted from the N pole of the other magnet 3 reaches the S pole of one magnet 3 through the magnet holding ring 2. That is, as in the first embodiment, no magnetic circuit is generated between the magnet 3 and the rotor 1. Therefore, no braking torque is generated in the rotor 1 that rotates integrally with the rotary shaft 10.

  At the time of complete braking, as shown in FIG. 21A, the first row of magnets 3A and the second row of magnets 3B are completely overlapped in the axial direction along the rotation axis 10, and further, The arrangement of the magnetic poles of the magnets 3A and 3B in the second row is completely coincident. In this case, the magnetic flux from the magnet 3 is as follows. As shown in FIG. 21A and FIG. 21B, the magnetic flux emitted from the N pole of one of the magnets 3 adjacent in the circumferential direction passes through the pole piece 4 and reaches the rotor 1. The magnetic flux that has reached the rotor 1 reaches the S pole of the other magnet 3 through the pole piece 4. The magnetic flux emitted from the N pole of the other magnet 3 reaches the S pole of one magnet 3 through the magnet holding ring 2. That is, a magnetic circuit similar to that of the first embodiment is formed. Therefore, the maximum braking torque is generated.

  Further, at the time of restraint braking, the state is an intermediate state between the non-braking state shown in FIGS. 20A and 20B and the complete braking state shown in FIGS. 21A and 21B. That is, the first row of magnets 3 </ b> A and the second row of magnets 3 </ b> B partially overlap in the axial direction along the rotation axis 10. In this case, as shown in FIGS. 21A and 21B, there is a magnetic flux reaching the rotor 1 from the magnet 3, but there is also a magnetic flux not reaching the rotor 1 from the magnet 3 as shown in FIGS. 20A and 20B. Therefore, the magnetic flux reaching the rotor 1 from the magnet 3 is less than that during complete braking. Therefore, the braking torque generated during restraint braking is lower than the maximum braking torque generated during complete braking.

  The configuration of the reduction gear according to the fourth embodiment may be applied to the reduction gears according to the second and third embodiments.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The present invention is useful for an eddy current type speed reducer using a permanent magnet.

DESCRIPTION OF SYMBOLS 1 Rotor 2, 2A, 2B Magnet holding ring 2a Lever 3, 3A, 3B Permanent magnet 4 Pole piece 7 Stator 7a Housing 10 Rotating shaft 11 Non-rotating part 20 Air cylinder (fluid pressure cylinder)
21 Piston rod 21a Tip 22 Spacer 22a Top 23 Air cylinder (actuator)
24 Rod 32 Spacer 32a Top surface 32b Stepped surface 33 Solenoid (actuator)
34 Rod 42 Spacer 42a Top surface 42b Stepped surface 43 Servo motor (actuator)
44 Rod

Claims (6)

A cylindrical rotor fixed to the rotating shaft;
A plurality of permanent magnets facing the rotor with a gap and arranged around the rotation axis,
A plurality of pole pieces provided in the gap between the rotor and the permanent magnet and arranged around the rotation axis;
A magnet holding ring for holding the permanent magnet;
A stator that rotatably supports the magnet holding ring around the rotation axis, and holds the pole piece;
A fluid pressure cylinder having a piston rod attached to the stator, the fluid pressure cylinder rotating the magnet holding ring in accordance with the advancement and retreat of the piston rod, and switching the position of the permanent magnet with respect to the pole piece;
An actuator having a rod and attached to the stator;
An eddy current reduction device comprising: a spacer connected to the rod of the actuator, wherein the spacer restricts advancement of the piston rod by contacting a tip of the piston rod that advances. The eddy current type speed reducer according to claim 1,
The speed reducer takes a state in which the spacer is disposed on an extension of the piston rod and a state in which the spacer is disengaged from the extension of the piston rod by the advance and retreat of the rod accompanying the operation of the actuator. , Eddy current type speed reducer. The eddy current type speed reducer according to claim 1 or 2,
The spacer has a top surface and a step surface of one step,
The speed reducer includes a state in which the top surface is disposed on an extension of the piston rod and a state in which the step surface is disposed on an extension of the piston rod by the advancement and retreat of the rod accompanying the operation of the actuator. Take, eddy current type speed reducer. The eddy current type speed reducer according to claim 1 or 2,
The spacer has a top surface and a plurality of step surfaces having a linear staircase shape,
The speed reducer includes a state in which the top surface is disposed on the extension of the piston rod and a state in which each step surface is disposed on the extension of the piston rod by the advance and retreat of the rod accompanying the operation of the actuator. And take, eddy current type speed reducer. The eddy current type speed reducer according to claim 1,
The spacer has a top surface and a step surface of one step,
The speed reducer includes a state in which the top surface is disposed on an extension of the piston rod and a state in which the step surface is disposed on an extension of the piston rod by rotation of the rod accompanying the operation of the actuator. Take, eddy current type speed reducer. The eddy current type speed reducer according to claim 1,
The spacer has a top surface and a plurality of step surfaces having a spiral staircase shape,
The speed reducer includes a state in which the top surface is disposed on an extension of the piston rod and a state in which each step surface is disposed on an extension of the piston rod by the rotation of the rod accompanying the operation of the actuator. And take, eddy current type speed reducer.

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