Actuator

Abstract

To provide technique capable of improving usefulness of an actuator for generating rotational movement with the usage of fluid as a working medium.SOLUTION: An actuator 100 includes a casing 110, a movable element 120 which is stored in the casing 110, and at least one movable partition wall 130 which partitions a space 160 formed between the casing 110 and the movable element 120 into a plurality of pressure chambers 162 arranged in a circumferential direction and is passively movable with respect to rotational movement of the movable element 120. The movable element 120 is rotated with multiple degrees of freedom by adjusting pressure of the plurality of pressure chambers 162.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to actuators. [Background technology]

[0002] There is known an actuator that uses a fluid as a working medium to generate rotational motion. This type of actuator generally produces high output. Patent Document 1 discloses a vane pump and a vane motor, which are one type of this type of actuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-232465 A Summary of the Invention [Problem to be solved by the invention]

[0004] As actuators of the above-mentioned type are increasingly being installed in various devices such as robots and machine tools, there is a demand for further improvements in their usefulness.

[0005] The present disclosure has been made in view of such problems, and one exemplary purpose of an embodiment thereof is to provide a technique for improving the usefulness of an actuator that generates rotational motion using a fluid as a working medium. [Means for solving the problem]

[0006] In order to solve the above problems, an actuator according to one embodiment of the present invention includes a housing, a mover housed in the housing, and at least one movable partition that is passively movable in response to rotational motion of the mover. The at least one movable partition divides a space formed between the housing and the mover into a plurality of pressure chambers arranged in a circumferential direction, and rotates the mover with multiple degrees of freedom by adjusting the pressures of the plurality of pressure chambers. Effect of the Invention

[0007] According to the present disclosure, it is possible to improve the usefulness of an actuator that generates rotational motion using a fluid as a working medium. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an actuator according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing the actuator body of FIG. [Diagram 3] FIG. 2 is a perspective view showing a biasing member and its periphery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, the background to the present embodiment will be described. Conventional actuators, such as vane pumps and vane motors, which use a fluid as a working medium to generate rotation, generate only one degree of freedom of rotation. Therefore, when a device in which the actuator is incorporated requires rotation with multiple degrees of freedom, the same number of actuators as the required degrees of freedom are required. This is an obstacle to making the device in which the actuator is incorporated smaller and lighter. The present embodiment has been made based on such knowledge.

[0010] Please refer to Figs. 1 and 2. In Figs. 1 and 2, the housing body 112 and the mover 120 are drawn transparently in order to explain the structure of the actuator body 102, but they do not need to be transparent and may be semi-transparent or opaque. In Fig. 2, the first isolation member 114_1 and the support shaft 116 are omitted. A fluid pressure rotary actuator (hereinafter simply referred to as "actuator") 100 according to an embodiment is an actuator capable of generating rotational motion with multiple degrees of freedom, and can be used in various devices including robots and machine tools. In the following, the working fluid of the actuator 100 is air. In other words, the actuator 100 is a pneumatic actuator. However, the technical ideas of the embodiment can also be applied to a gas pressure actuator whose working fluid is a gas other than air and a liquid pressure actuator whose working fluid is a liquid, as long as there is no contradiction.

[0011] The actuator 100 includes an actuator body 102 and a pressure controller 104. The actuator body 102 includes a housing 110, a mover 120, three moveable partitions 130_1 to 130_3 (hereinafter, when no distinction is made or when they are collectively referred to as "movable partitions 130"), and a rod 150.

[0012] For ease of explanation, an XYZ orthogonal coordinate system is considered, with a certain horizontal direction as the X-axis, a horizontal direction perpendicular to the X-axis as the Y-axis, and a vertical direction perpendicular to both as the Z-axis. The Z-axis direction is sometimes referred to as the up-down direction. In the state of FIGS. 1 and 2, the extension direction of the end face 130c of the first movable partition wall 130_1 coincides with the X-axis direction, the mover 120 is parallel to the XY plane, and the extension direction of the rod 150 coincides with the Z-axis direction. Such directional notations do not limit the posture of the actuator body 102, and the actuator body 102 can be used in any posture.

[0013] The housing 110 includes a housing main body 112 and three isolation members 114_1 to 114_3 (hereinafter, referred to as "isolation members 114" when no particular distinction is made or when they are collectively referred to).

[0014] The housing body 112 is a member having a concave spherical recess 112a on its inner wall. When the actuator body 102 is incorporated into an apparatus, the housing body 112 is supported by the apparatus. The recess 112a of the housing body 112 accommodates the mover 120. Note that the inner wall of the recess 112a may be concave spherical only in the portion where the mover 120 slides and in the portion where the three movable partition walls 130 slide.

[0015] The external shape of the housing body 112 is approximately spherical. In other words, the housing body 112 is a spherical shell (i.e., a hollow sphere) with a circular hole 112b provided in one part. However, the external shape of the housing body 112 is not particularly limited. For example, the external shape of the housing body 112 may be a cube or other shape. The hole 112b may be other than a circle, and may be, for example, a polygonal shape. The size of the hole 112b is not particularly limited as long as it does not interfere with the rod 150.

[0016] The material of the housing body 112 is not particularly limited. For example, the housing body 112 may be made of metal or resin. The housing body 112 may be made by joining a plurality of members. For example, the housing body 112 may be made by joining two approximately hemispherical members. In this case, a seal member such as an O-ring may be disposed at the joint to prevent leakage of the working fluid from the joint.

[0017] The three isolating members 114 are provided on the bottom surface of the recess 112a. The three isolating members 114 may be formed separately from the housing body 112 and then fixed to the housing body 112, or may be molded integrally with the housing body 112. In this embodiment, the three isolating members 114 have the same shape. The material of the three isolating members 114 is not particularly limited. For example, the three isolating members 114 may be made of metal or resin.

[0018] The first isolating member 114_1 is a member that closes the gap between the first movable partition wall 130_1 and the second movable partition wall 130_2. The second isolating member 114_2 is a member that closes the gap between the second movable partition wall 130_2 and the third movable partition wall 130_3. The third isolating member 114_3 is a member that closes the gap between the third movable partition wall 130_3 and the first movable partition wall 130_1.

[0019] The mover 120 is housed in the recess 112a of the housing main body 112. The mover 120 is a disk-shaped member. The mover 120 is disposed in the recess 112a so that its center is located at the center of the concave spherical surface of the recess 112a, and is supported tiltably by the spherical bearing 118 disposed at the center. In other words, the center of rotation of the mover 120 is constrained by the spherical bearing 118.

[0020] There is no particular limitation on the material of the mover 120. For example, the mover 120 may be made of metal or resin.

[0021] The movable element 120 has an outer diameter equal to the inner diameter of the concave spherical surface of the recess 112a. Therefore, the outer peripheral surface 120a of the movable element 120 is in contact with the inner wall of the recess 112a over the entire circumference. An elastic member such as rubber may be attached to the outer peripheral surface 120a of the movable element 120. In this case, leakage of the working fluid from between the movable element 120 and the housing body 112 is prevented.

[0022] The spherical bearing 118 is a sliding bearing in which an outer ring 118a and an inner ring (not shown) are in spherical contact with each other. The outer ring 118a is fixed to the mover 120. The inner ring is fixed to the support shaft 116 and thus to the housing body 112.

[0023] Rod 150 is a member that outputs the rotational motion of mover 120 to the outside. One end of rod 150 is fixed to mover 120 via spherical bearing 118, extends perpendicular to disk-shaped mover 120, and the other end protrudes outside housing main body 112.

[0024] The three movable partitions 130 are housed in a space 160 between the mover 120 and the housing main body 112. The first movable partition 130_1, the second movable partition 130_2, and the third movable partition 130_3 are arranged in this order in the circumferential direction in the space 160. The three movable partitions 130 divide the space 160 into three pressure chambers 162 arranged in the circumferential direction. In this embodiment, the three movable partitions 130 are arranged at equal intervals in the circumferential direction, i.e., at intervals of 120°.

[0025] In detail, a first pressure chamber 162_1 is defined by the housing body 112, the first isolation member 114_1, the movable element 120, the first movable partition 130_1, and the second movable partition 130_2. A second pressure chamber 162_2 is defined by the housing body 112, the second isolation member 114_2, the movable element 120, the second movable partition 130_2, and the third movable partition 130_3. A third pressure chamber 162_3 is defined by the housing body 112, the third isolation member 114_3, the movable element 120, the third movable partition 130_3, and the first movable partition 130_1.

[0026] Although not limited thereto, the three movable partitions 130 are plate-like members with a cut-out central portion of a sector whose center coincides with the center of the concave spherical surface of the recess 112a. The outer peripheral surface 130a of the movable partition 130 is arc-shaped and slides against the inner wall of the recess 112a of the housing body 112. A seal member such as rubber or a magnetic material may be attached to the outer peripheral surface 130a of the movable partition 130. Alternatively, a seal member such as rubber may be attached to the portion of the inner wall of the recess 112a of the housing body 112 with which the outer peripheral surface 130a of the movable partition 130 slides. In these cases, leakage of the working fluid from between the outer peripheral surface 130a of the movable partition 130 and the inner wall of the recess 112a of the housing body 112 can be prevented.

[0027] The inner circumferential surface 130b of the movable partition wall 130 is arc-shaped and comes into sliding contact with, for example, the spherical bearing 118. A seal member such as rubber may be attached to the inner circumferential surface 130b of the movable partition wall 130. Alternatively, a seal member such as rubber may be attached to the portion of the outer circumferential surface of the spherical bearing 118 with which the inner circumferential surface 130b of the movable partition wall 130 comes into sliding contact. In these cases, leakage of the working fluid from between the inner circumferential surface 130b of the movable partition wall 130 and the spherical bearing 118 can be prevented.

[0028] The two end faces 130c, 130d that connect to the outer peripheral face 130a and the inner peripheral face 130b are formed in a straight line, although the end face 130d does not have to be in a straight line.

[0029] The pressure controller 104 independently controls the pressure of the working fluid in the three pressure chambers 162. For example, the pressure controller 104 may include a pump, a compressor, and a pressure control valve. The working fluid may be a gas such as air,

[0030] Please refer to FIGS. 1 to 3. The actuator body 102 further includes three biasing members 140 (only two biasing members 140 are shown in FIG. 3). The movable partition 130 is biased toward the mover 120 by the corresponding biasing member 140. As a result, one end face 130c of the two end faces 130c, 130d of the movable partition 130 contacts the lower face 120b of the mover 120. In addition, since the movable partition 130 is biased toward the mover 120 by the biasing member 140, when the mover 120 rotates (tilts) around the X-axis and / or the Y-axis, the movable partition 130 moves in the angular direction of the sector (the direction of the arrow in FIGS. 1 and 2). That is, the movable partition 130 can move passively in response to the movement of the mover 120 around the X-axis and / or the Y-axis. In particular, the movable partition 130 is biased toward the movable element 120 by the biasing member 140, so that the end face 130c maintains contact with the lower face 120b of the movable element 120 even when the movable element 120 rotates around the X-axis and / or the Y-axis. This makes it possible to prevent leakage of the working fluid from between the movable partition 130 and the movable element 120.

[0031] The biasing member 140 may be an elastic member such as a mechanical spring, a pneumatic spring, or a magnetic spring. That is, the movable partition wall 130 may be elastically supported by an elastic member. In the example of Fig. 3, the biasing member 140 is a coil spring (i.e., a mechanical spring) with one end fixed to the support shaft 116 and the other end fixed to the end surface 130d of the movable partition wall 130.

[0032] As described above, the movable partition 130 moves with the rotation (tilt) of the movable element 120, but the isolating member 114 and the movable partition 130 overlap each other so that the gap between the movable partitions 130 is kept blocked by the isolating member 114 even when the movable partition 130 moves. In other words, the first movable partition 130_1 moves through a gap (not shown) between the first isolating member 114_1 and the third isolating member 114_3, and the end surface 130d of the first movable partition 130_1 is always located in the gap. The second movable partition 130_2 moves through a gap 170 between the second isolating member 114_2 and the third isolating member 114_3, and the end surface 130d of the second movable partition 130_2 is always located in the gap 170. The third movable partition 130_3 moves through a gap 172 between the third isolating member 114_3 and the first isolating member 114_1, and an end face 130d of the third movable partition 130_3 is always positioned in the gap 172.

[0033] The end surface 130c of the movable partition 130 is configured so that the mover 120 can tilt with respect to the movable partition 130. More specifically, the end surface 130c has a convex shape and is in line contact with the lower surface 120b of the mover 120. For example, the end surface 130c may have an inverted U-shaped cross-sectional shape or an inverted V-shaped cross-sectional shape. The end surface 130c has a convex shape so that the mover 120 can tilt with respect to the movable partition 130.

[0034] End surface 130c of movable partition 130 may be made of an elastic member such as rubber. For example, the elastic member that makes up end surface 130c may be attached to the main body of movable partition 130. When end surface 130c is made of an elastic member, movable element 120 can tilt with respect to movable partition 130 regardless of the shape of end surface 130c.

[0035] The above is the basic configuration of the actuator 100. Next, the operating principle of the actuator 100 will be described.

[0036] For example, when the first pressure chamber 162_1 is pressurized while the second pressure chamber 162_2 and the third pressure chamber 162_3 are depressurized, the mover 120 rotates around the Y axis due to the pressure difference among the three pressure chambers 162. On the other hand, when the first pressure chamber 162_1 is depressurized while the second pressure chamber 162_2 and the third pressure chamber 162_3 are pressurized, the mover 120 rotates around the Y axis in the opposite direction.

[0037] Furthermore, for example, when the second pressure chamber 162_2 is pressurized and the third pressure chamber 162_3 is depressurized, the mover 120 rotates around the X axis due to the pressure difference among the three pressure chambers 162. On the other hand, when the third pressure chamber 162_3 is pressurized and the second pressure chamber 162_2 is depressurized, the mover 120 rotates around the X axis in the opposite direction due to the pressure difference among the three pressure chambers 162.

[0038] Although a detailed description is omitted, by adjusting the pressure in the three pressure chambers 162, the mover 120 rotates around the X-axis and Y-axis.

[0039] As described above, according to this embodiment, it is possible to realize actuator 100 that can rotate mover 120 about the X-axis and / or about the Y-axis, that is, that can rotate mover 120 with multiple degrees of freedom. In this case, it is possible to reduce the number of actuators 100 mounted on devices such as robots and machine tools.

[0040] Furthermore, according to this embodiment, the three movable partitions 130 are disposed at equal intervals in the circumferential direction. In this case, it becomes relatively easy to calculate the pressure for applying a target rotational force to the mover 120.

[0041] The present disclosure has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present disclosure.

[0042] (Variation 1) In the embodiment and the above-mentioned modified example, a case has been described in which three movable partitions 130 divide the space 160 between the movable element 120 and the housing main body 112 into three pressure chambers 162, but the number of movable partitions 130 and the number of pressure chambers 162 are not limited to this.

[0043] The number of pressure chambers 162 may be four or more. In this case, the actuator 100 typically includes n (n≧4) movable partitions 130, which partition the space 160 between the mover 120 and the housing main body 112 into n pressure chambers 162 arranged in the circumferential direction. The actuator 100 also includes n biasing members 140, and the n movable partitions 130 are biased toward the mover 120 by the corresponding biasing members 140. The actuator 100 adjusts the pressures of the n pressure chambers 162 by the pressure controller 104, thereby allowing the mover 120 to rotate around the X-axis and / or the Y-axis, as in the embodiment.

[0044] Also, the number of pressure chambers 162 may be two. In this case, the mover 120 can rotate around a certain axis by adjusting the pressures in the two pressure chambers 162. Furthermore, when the mover 120 receives an external force via the rod 150, it is also allowed to rotate around an axis perpendicular to the axis.

[0045] (Variation 2) In the embodiment and the above-mentioned modified example, the case where the number of movable partitions 130 and the number of pressure chambers 162 are the same has been described, but the present invention is not limited to this. For example, the actuator 100 may include n-1 (n≧2) movable partitions 130, and the n-1 movable partitions 130 may partition the space 160 between the mover 120 and the housing main body 112 into n pressure chambers 162. In other words, one movable partition 130 may be formed in a substantially sector shape with a central angle of 180 degrees and serve as two movable partitions 130.

[0046] (Each Aspect of the Present Disclosure) An actuator according to an aspect of the present disclosure includes a housing, a mover housed in the housing, and at least one movable partition that is passively movable in response to the rotational motion of the mover, and the at least one movable partition divides a space formed between the housing and the mover into a plurality of pressure chambers arranged in a circumferential direction, and rotates the mover with multiple degrees of freedom by adjusting the pressures of the plurality of pressure chambers. In this case, the number of actuators mounted on a device such as a robot or a machine tool can be reduced.

[0047] In one embodiment, the housing has a recess with an inner wall having a concave spherical shape, the movable element is disk-shaped and housed in the recess, and each of the at least one partition has an arc-shaped outer circumferential surface that contacts the inner wall of the recess.

[0048] In one embodiment, a biasing member may be provided that biases the at least one movable partition toward the movable element, whereby leakage of the working fluid from between the movable partition and the movable element can be prevented.

[0049] In one embodiment, an end surface of the at least one movable partition that comes into contact with the mover may be configured so that the mover can tilt relative to the movable partition.

[0050] In one embodiment, the center of rotation of the mover may be constrained by a spherical bearing disposed at the center of the inner wall of the recess.

[0051] In one embodiment, a pressure controller is provided for adjusting the pressure in the multiple pressure chambers. [Explanation of symbols]

[0052] 100 actuator, 102 actuator body, 110 housing, 112 housing body, 112a recess, 120 mover, 130 movable partition, 160 space, 162 pressure chamber.

Claims

1. A housing and A mover housed in the housing; and At least one movable partition passively movable relative to the rotational movement of the mover; Equipped with the at least one movable partition divides a space formed between the housing and the movable element into a plurality of pressure chambers arranged in a circumferential direction; An actuator that rotates the mover with multiple degrees of freedom by adjusting the pressure in the multiple pressure chambers.

2. The housing has an inner wall having a concave spherical recess, The mover is disk-shaped and is housed in the recess, The actuator according to claim 1 , wherein each of the at least one movable partition walls has an arcuate outer circumferential surface that contacts the inner wall of the recess.

3. The actuator of claim 1 , further comprising a biasing member biasing the at least one movable partition toward the armature.

4. The actuator according to claim 3 , wherein an end surface of the at least one movable partition that comes into contact with the mover is configured so that the mover can tilt relative to the movable partition.

5. The actuator according to claim 2 , wherein the center of rotation of the mover is constrained by a spherical bearing disposed at the center of the inner wall of the recess.

6. The actuator according to claim 1 , further comprising a pressure controller for adjusting the pressures in the plurality of pressure chambers.

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