KR20210088418A - Actuator - Google Patents

Abstract

Provided is an actuator configured to move a rod in an axial direction and rotate in a circumferential direction, the actuator being easily assembled.
The actuator 100 includes a cylinder 102, a piston 104 slidably accommodated in the cylinder 102, and a rod 106 extending from the piston 104 and protruding to the outside of the cylinder 102, A rotational driving source for rotationally driving the rod 106 coaxially with the rod 106 and a support portion 108 for rotatably supporting the rod 106 are provided. The support part 108 is configured to allow the central axis of the rod 106 to shift with respect to the central axis of the support part 108 .

Description

actuator {Actuator}

This application claims priority based on Japanese Patent Application No. 2020-000442 filed on January 6, 2020. The entire contents of the application are incorporated herein by reference.

The present invention relates to an actuator.

Patent Document 1 discloses a fluid pressure actuator that slides a rod in an axial direction using a fluid as a working medium. This fluid pressure actuator is configured so that the rod can also be rotated in the circumferential direction by the driving force transmitted through the belt from the rotational drive.

Patent Document 1: Japanese Patent Application Laid-Open No. 2017-133593

The actuator as disclosed in Patent Document 1 is generally difficult to assemble, and even if assembled, the piston may bite (scratch or contact) the cylinder.

The present invention has been made in view of this situation, and one of the exemplary objects of one aspect is to provide an actuator configured to move the rod in the axial direction and rotate it in the circumferential direction, and to provide an actuator that is easy to assemble it is in

In order to solve the above problems, the actuator of an aspect of the present invention includes a cylinder, a piston slidably accommodated in the cylinder, a rod extending from the piston and protruding to the outside of the cylinder, and a rod for rotating the rod and A rotation drive source having a coaxial rotation shaft and a support portion for rotatably supporting the rod are provided. The support part is configured to allow the central axis of the rod to shift with respect to the central axis of the support part.

However, arbitrary combinations of the above components, and those in which the components and expressions of the present invention are substituted for each other among methods, apparatuses, systems, etc. are also effective as aspects of the present invention.

Advantageous Effects of Invention According to the present invention, an actuator configured to move a rod in an axial direction and rotate in a circumferential direction can be provided, and an actuator that is easy to assemble can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematically the actuator which concerns on 1st Embodiment.
It is a figure which shows schematically the actuator which concerns on 2nd Embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated, referring drawings based on suitable embodiment. The same code|symbol shall be attached|subjected to the same or equivalent component, member, and a process shown in each figure, and overlapping description is abbreviate|omitted as appropriate. In addition, embodiment does not limit invention, It is an illustration, and all the characteristics described in embodiment and its combination are not necessarily limited to what is essential of invention.

(First embodiment)

1 is a diagram schematically showing an actuator 100 according to a first embodiment. The actuator 100 is a fluid pressure actuator using a fluid as a working medium. Hereinafter, a case in which air is used as the working medium is exemplified.

The actuator 100 includes a cylinder 102 , a piston 104 , a rod 106 , a support part 108 , a pressure adjusting part 110 , a rotational drive source 112 , and a controller 114 . do.

Hereinafter, a direction parallel to the central axis of the cylinder 102 is referred to as an axial direction, and a direction along the circumference of a circle perpendicular to the central axis centering on the central axis of the cylinder 102 will be described as the circumferential direction.

The cylinder 102 includes a cylinder portion 116 , a bottom portion 118 , and a cover portion 120 . The hollow part 116a of the cylindrical part 116 has a circular cross section. Specifically, the central axis of the cylinder 102 described above refers to the central axis of the hollow portion 116a of the cylindrical portion 116 . Although the external shape of the cylinder part 116 is not specifically limited, For example, it has a rectangular cross section. The bottom part 118 closes one end (left end in FIG. 1) of the cylinder part 116, and the cover part 120 closes the other end (right end in FIG. 1) of the cylinder part 116. As shown in FIG. The bottom part 118 and the cover part 120 may be formed integrally with the cylindrical part 116, respectively, and may be combined with the cylindrical part 116 after being formed separately from the cylindrical part 116. As shown in FIG. The cover part 120 is formed with a rod insertion hole 120a penetrating the cover part 120 in the axial direction.

The piston 104 is accommodated in the cylinder 102 . The piston 104 includes a cylindrical first piston head 122 , a cylindrical second piston head 124 , and a connecting portion 126 connecting the first piston head 122 and the second piston head 124 . includes The connection part 126 may be integrally formed with the first piston head 122 and the second piston head 124 , and formed separately from at least one of the first piston head 122 and the second piston head 124 . It may be combined later. The piston 104 is accommodated in the cylinder 102 so that the first piston head 122 is located on the bottom portion 118 side and the second piston head 124 is located on the cover portion 120 side.

Due to the piston 104 , the space in the cylinder 102 is located on the opposite side to the rod 106 (ie, the bottom 118 side) with respect to the piston 104 (specifically, the first piston head 122 ). The first cylinder chamber 128 and the second cylinder chamber located on the rod 106 side (that is, the cover portion 120 side) with respect to the piston 104 (specifically, the second piston head 124) ( 130). In the cylinder part 116 , a first port 132 for supplying and discharging compressed gas to and from the first cylinder chamber 128 , and a second port 132 for supplying and discharging compressed gas to and from the second cylinder chamber 130 . A port 134 is formed.

An air pad 162 as a static pressure air bearing is provided on the outer peripheral surface 122a of the first piston head 122 . An air supply hole (not shown) is provided in the air pad 162 . Compressed air supplied from a supply machine (not shown) through this air supply hole passes through a first gap 136 that is a gap between the inner peripheral surface 116b of the cylindrical portion 116 and the outer peripheral surface 122a of the first piston head 122 . is supplied to As a result, a high-pressure gas layer is formed in the first gap 136 , and the air pad 162 and thus the first piston head 122 float from the cylinder 102 .

The rod 106 is an elongated member, inserted into the rod insertion hole 120a, one end connected to the piston 104 and the other end protruding outside the cylinder 102 . The rod 106 may be integrally formed with the piston 104 , or may be formed separately from the piston 104 and then coupled to the piston 104 . The rod 106 has a polygonal (eg, rectangular) cross section.

The pressure adjusting unit 110 adjusts the pressure in the first cylinder chamber 128 and the pressure in the second cylinder chamber 130 . The pressure adjusting unit 110 supplies air pressure-reduced by the servo valve to the first cylinder chamber 128 through the first port 132 , and the second cylinder chamber 130 through the second port 134 . supply air at constant pressure. However, the pressure adjusting unit 110 is not limited to such a configuration, and, for example, servos the pressure of the air supplied to the first cylinder chamber 128 and the pressure of the air supplied to the second cylinder chamber 130 . It may be configured to adjust each with a valve.

The rotational drive source 112 is a drive source for rotating the rod 106 in the circumferential direction in a predetermined angle range. In particular, the rotational drive source 112 has a rotational axis coaxial with the central axis of the rod 106 to be rotationally driven, and thus directly rotates the rod 106 without intervening a transmission mechanism. Accordingly, as in the case of rotating the rod by transmitting the rotation of the rotational drive source having a rotational axis non-coaxial with the central axis of the rod to the belt as in the conventional actuator as described in Patent Document 1, the rotational direction The positioning accuracy of the rod 106 is improved, and the responsiveness is also improved.

The rotational drive source 112 is, in the illustrated example, a direct drive motor, and includes a rotor 144 and a stator 146 surrounding the rotor 144 . The rotor 144 is a magnet and is fixed to the outer periphery of the first annular member 166 . The first circumferential member 166 has an inner peripheral surface 166a having a polygonal cross-section corresponding to the rod 106 and an outer peripheral surface 166b having a circular cross-section. The first circumferential member 166 is fixed to the rod 106 by turning the rod 106 . The stator 146 is provided with a coil 160 so as to face the rotor 144 in the radial direction. As a driving current is supplied to the coil 160, a magnetic field is generated around the coil 160, and by the electromagnetic action of the coil 160 and the opposing rotor (magnet) 144, the rotor 144 and the rod ( 106) and the piston 104 are rotationally driven. However, although the first annular member 166 is separate from the rod 106 , the first annular member 166 may be formed integrally with the rod 106 . That is, the first circumferential member 166 may be a part of the rod 106 .

The support part 108 is provided between the cylinder 102 and the rotation drive source 112 . The support part 108 supports the rod 106 so as to be slidable in the axial direction and rotatably in the circumferential direction. The support portion 108 includes a housing 148 , a single-row bearing 150 accommodated in the housing 148 , and a second second that is fitted inside the bearing 150 and surrounds the rod 106 . It includes a circumferential member (168).

The housing 148 is a cylindrical member, and the hollow part 148a has a circular cross section. Although the outer shape of the housing 148 is not specifically limited, It has a rectangular cross section. The housing 148 is connected to the cylindrical portion 116 so that the hollow portion 148a is coaxial with the central axis of the cylinder 102 .

The bearing 150 is a ball bearing in the illustrated example, and is disposed inside the housing 148 so that its central axis is coaxial with the central axis of the cylinder 102 .

The second circumferential member 168 has an inner peripheral surface 168a having a polygonal cross-section corresponding to the rod 106 and an outer peripheral surface 168b having a circular cross-section corresponding to the inner ring 150a of the bearing 150 . . An air pad 164 as a static pressure air bearing is provided on the outer peripheral surface 106a of the rod 106 so as to face the inner peripheral surface 168a of the second circumferential member 168 . The air pad 164 is provided with an air supply hole (not shown). Compressed air supplied from a supply machine (not shown) through this air supply hole passes through a second gap 138 that is a gap between the inner circumferential surface 168a of the second circumferential member 168 and the outer circumferential surface 106a of the rod 106 . is supplied to As a result, a high-pressure gas layer is formed in the second gap 138 , and the air pad 164 and thus the rod 106 float from the second circumferential member 168 . However, the second circumferential member 168 receives a rotational force from the rod 106 through the high-pressure gas layer formed in the second gap 138 , and rotates with the rod 106 in a non-contact state with the rod 106 . do.

The piston 104 and the rod 106, through the air pads 162 and 164 as static pressure air bearings, in a non-contact state with the cylinder 102 and the support part 108, in the axial direction (left and right in FIG. 1) slidably supported. Thereby, the movement of the piston 104 and the rod 106 becomes smooth, and high-precision positioning and control of a force are attained. However, in FIG. 1, although the 1st clearance gap 136 and the 2nd clearance gap 138 are exaggerated, in reality, the 1st clearance gap 136 and the 2nd clearance gap 138 are about several microns, for example.

Subsequently, although not illustrated, the actuator 100 of the present embodiment includes a position detection unit that detects the axial position and the rotational position of the rod 106 or piston 104 . The position detecting unit detects the axial position and the rotational position of the rod 106 or the piston 104 at a predetermined cycle, and an axial position signal indicating the detected axial position and a rotational position indicating the detected rotational position A signal is output to the controller 114 .

The controller 114 outputs a movement command to the pressure adjusting unit 110 so that the difference between the axial position signal and the external position command value is eliminated. The pressure adjusting unit 110 drives the servovalve based on the movement command, and performs positioning control of the rod 106 in the axial direction.

Moreover, the controller 114 outputs a rotation command to the rotation drive source 112 so that the difference between the rotation direction position signal and the position command value from the outside is eliminated. The rotation drive source 112 is driven based on the rotation command, and performs positioning control in the rotation direction of the rod 106 .

In addition, when the load control is performed, the controller 114 is configured so that the difference between the load generated by the pressure difference between the first cylinder chamber 128 and the second cylinder chamber 130 and the load command from the outside disappears, A load command is output to the pressure adjusting unit 110 . The pressure adjusting unit 110 drives the servovalve based on the load command, and performs load control for applying a load (force) to the rod 106 .

The above is the basic configuration of the actuator 100 . Next, the structure of the support part 108 is demonstrated in more detail.

Realistically, it is not easy to assemble the support 108 , that is, the central axis of the bearing 150 to be coaxial with the central axis of the cylinder 102 . The housing 148 is formed so that the hollow part 148a has a perfect circular cross section so that the central axis of the housing 148 (more specifically, the hollow part 148a) is coaxial with the central axis of the cylinder 102 . The housing 148 is connected to the cylinder 102 , and then the bearing 150 must be positioned so that the central axis of the bearing 150 is coaxial with the housing 148 or the central axis of the cylinder 102 . In practice, errors may occur in these, and as a result, a situation may occur in which the piston 104 is bitten (scratched or contacted) with the cylinder 102 .

On the other hand, in the conventional actuator as described in Patent Document 1, since rotation of a rotational drive source having a rotational axis non-coaxial with the rod is transmitted to the rod by the belt, the rod is pulled by the belt in a direction orthogonal to the axial direction. pulled In order to counteract the pulling force in the direction orthogonal to the axial direction, in the conventional actuator, high rigidity is required for the support part which supports the rod. In contrast, in the present embodiment, as described above, since the rod 106 is rotated by the rotational drive source 112 having a rotation shaft coaxial with the rod 106, the rod 106 is rotated in a direction orthogonal to the axial direction. not attracted to Accordingly, the rigidity required for the support 108 is relatively low.

Therefore, in this embodiment, the support part 108 is not provided with the bearing 150 of several rows, but is provided with only the bearing 150 of single row purposely as mentioned above. And the bearing 150 is a range which does not impair the function as a bearing in design, WHEREIN: It is comprised so that the central axis of the rod 106 may shift|deviate with respect to the central axis of the said bearing 150. FIG. Here, the deviation of the central axis of the rod 106 with respect to the central axis of the bearing 150 means that the rod 106 moves slightly in parallel in the radial direction so that the central axis of the rod 106 and the central axis of the bearing 150 are shifted. This means that the state does not coincide (does not overlap), or the rod 106 is slightly inclined and the central axis of the rod 106 is inclined with respect to the central axis of the bearing 150 . Allowing the shift may be realized, for example, by intentionally making the internal clearance of the bearing 150 relatively large. Accordingly, even if the central axis of the bearing 150 is slightly shifted with respect to the central axis of the housing 148 or the cylinder 102, the bearing 150 is absorbed by allowing the shift, and the piston 104 and the rod 106 are displaced. Biting (scratches) is suppressed. In addition, assembling of the actuator 100 becomes relatively easy, and the assembling cost can be reduced.

The actuator 100 configured as described above is used, for example, in a die bonding process or a mounting process of a semiconductor chip. Specifically, in the semiconductor manufacturing apparatus, a tool for holding a semiconductor chip slides (moves) the rod 106 attached to the tip in the axial direction. Alternatively, the rod 106 is rotated in a required angle range. Thereby, the semiconductor chip can be mounted on a mounting surface, such as a lead frame or a board|substrate.

(Second embodiment)

2 is a diagram schematically showing an actuator 200 according to the second embodiment. FIG. 2 corresponds to FIG. 1 . Hereinafter, the actuator 200 will be described focusing on differences from the actuator 100 according to the first embodiment.

The actuator 200 includes a cylinder 102 , a piston 104 , a rod 106 , a support part 208 , a pressure adjusting part 110 , a rotational drive source 112 , and a controller 114 . do. That is, in this embodiment, the support part 208 is provided instead of the support part 108 . Moreover, in this embodiment, the rod 106 has a circular cross section.

The support part 208 is axially slidable and rotatable in the circumferential direction with the rod 106 in a non-contact state, and furthermore, the central axis of the rod 106 with respect to the central axis of the support part 208 is support to allow deviations. In the illustrated example, the support portion 208 includes a housing 148 , a magnet 252 fixed to the outer circumferential surface of the rod 106 , and a plurality of coils 254 provided in the housing 148 to surround the magnet 252 . ), and supports the rod 106 by magnetic force. However, a plurality of coils may be provided on the outer peripheral surface of the rod 106 , and a magnet may be fixed to the inner peripheral surface of the housing 148 to surround the plurality of coils.

In addition, the support 208 includes a plurality of sensors (only one sensor is shown in FIG. 2 ) 256 for measuring the distance between the rod 106 and the housing 148 . The plurality of sensors 256 are arranged, for example, 45 degrees apart in the circumferential direction. The plurality of sensors 256 measure the distance between the rod 106 and the housing 148 at a predetermined period, and transmit the measurement result to the controller 114 .

The controller 114 controls, based on the measurement result, the current flowing through the coil to fix the rod 106 at a position where the central axis of the rod 106 overlaps the central axis of the support 208 or the cylinder 102 . Controls size and orientation. Since such a control method is well-known, the above description is abbreviate|omitted.

However, the support part 208 is not limited to such a structure. The support portion 208 may be configured to support the rod 106 in a non-contact manner by providing, for example, a static pressure air bearing between the rod 106 and the rod 106 , as long as it can support the rod 106 in a non-contact manner.

According to the actuator 200 of this embodiment, the same effect as the actuator 100 of 1st embodiment can be exhibited.

In addition, although the rod 106 is supported in a non-contact manner in this embodiment, when the rod 106 is supported in a non-contact manner, when the rod 106 rotates, its central axis is the center of the support portion 208 or the cylinder 102 . deviating from the axis. In this state, if the rod 106 is rotated at high rotation, for example, the rod 106 will vibrate. On the other hand, according to this embodiment, the support part 208 is controlled so that the central axis of the rod 106 may be fixed at the position which overlaps with the central axis of the support part 208 and the cylinder 102. As shown in FIG. That is, the support part 208 is controlled so as to suppress a shift of the central axis of the rod 106 with respect to the central axis of the support part 208 or the cylinder 102 . In this case, the shift between the central axis of the rod 106 and the central axis of the support portion 208 and the cylinder 102 is suppressed. Thereby, even if it rotates the rod 106 at high rotation, for example, the vibration of the rod 106 is suppressed. In other words, since the shift is suppressed, the rod 106 can be rotated at a higher rotation, that is, it can be positioned in the rotational direction in a shorter time.

Moreover, in this embodiment, the piston 104 and the rod 106 are slidably supported in the axial direction by the 1st static pressure air bearing 140 and the support part 208. As shown in FIG. In this case, since the static pressure fluid bearing becomes unnecessary in the 2nd clearance gap 138, the cost can be reduced by that much.

As mentioned above, this invention was demonstrated based on embodiment. This embodiment is an illustration, and it will be understood by those skilled in the art that various modifications are possible for the combination of each component or each processing process, and that such a modification is also within the scope of the present invention.

100, 200 actuators
102 cylinder
104 piston
106 rods
112 rotary drive source
108, 208 support

Claims (5)

cylinder and
a piston slidably accommodated in the cylinder;
a rod extending from the piston and protruding to the outside of the cylinder;
a rotational drive source for rotating the rod and having a rotation shaft coaxial with the rod;
and a support for rotatably supporting the rod;
The support part is configured to allow the central axis of the rod to shift with respect to the central axis of the support part. According to claim 1,
The support part supports the rod in a non-contact manner, and is controlled to suppress a shift of a central axis of the rod with respect to a central axis of the support part. 3. The method of claim 2,
The support part supports the rod in a non-contact manner by magnetic force, and is controlled to suppress a shift of the central axis of the rod with respect to the central axis of the support part. According to claim 1,
The support part includes a bearing configured to support the rod so as to allow the central axis of the rod to shift with respect to the central axis of the support part. 5. The method of claim 4,
The bearing is an actuator, characterized in that it is a single-row ball bearing.

Images