Air-driven actuator and method for manufacturing air-driven actuator

Abstract

Provided are an air-driven actuator and a method for manufacturing the air-driven actuator, the air-driven actuator being easy to process, enabling a desired cylinder speed to be easily obtained, and enabling compactness, particularly in a double-acting type, to be achieved while enlarging the space between two air ports. An air-driven actuator (1) is provided with: a cylinder (10) in which at least one air port (15) is provided at a rod-side end (10a) on which a piston rod guide (50) is provided, and in which a piston reciprocating space (13) in which a piston (20) reciprocates is formed; the cylinder (10) has an enlarged diameter section (14) provided so as to enlarge the inner diameter in a region adjacent to the piston rod guide (50) in the reciprocating direction of the piston (20). The air port (15) has a lower hole (15a) including: a through-hole portion (15aa) penetrating through the cylinder (10) by overlapping a portion of the lower hole (15a) in the radial direction with the enlarged diameter portion (14) in the reciprocating direction of the piston (20) and communicating with the enlarged diameter portion (14); and a non-penetrating portion (15ab) that does not penetrate into the cylinder (10).

Description

Technical Field

[0001] The present invention relates to an air-driven actuator and a method for manufacturing the air-driven actuator, and more particularly to an air-driven actuator in which a piston reciprocates by sucking and discharging air through an air port and a method for manufacturing the air-driven actuator. Background Art

[0002] Conventionally, as one of the driving sources for opening and closing the valve, an air-driven actuator operated by air pressure has been used.

[0003] As air-driven actuators that operate by air pressure, there are two types of actuators commonly used: a double-acting type that uses air pressure for both opening and closing operations of a valve, and a single-acting type that uses a spring force for either opening or closing operations of a valve.

[0004] For example, Patent Document 1 describes a double-acting valve actuator as follows: two communication ports 43 provided in the cylinder portion 3 and communicating with the outside serve as air intake and exhaust ports (air ports), and air pressure is alternately supplied to both sides of the internal piston 42 through these communication ports 43, causing the piston 42 to reciprocate. The reciprocating motion of the piston 42 causes the scotch yoke 33 to rotate through the piston rod 30 and the stop pin 31, and the shaft 32 integral with the scotch yoke 33 rotates, thereby performing both opening and closing actions by air pressure.

[0005] The double-acting valve actuator described in patent document 1 is as shown in Figure 8 of patent document 1, in which the connecting port 43 on the piston rod 30 side is made into a curved shape that does not pass through the cylinder part 3 in a straight line but is provided with a transverse hole (a hole in the reciprocating motion direction of the piston 42) to communicate with the cylinder part 3.

[0006] The valve actuator described in Patent Document 1 has a connecting port 43 (air port) at the end of the cylinder 3 on the side where the piston rod 30 is pulled out, the so-called rod-side end, which is connected to the inside of the cylinder 3 via a horizontal hole provided in the wall of the cylinder 3.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 6430173 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, the valve actuator described in Patent Document 1 has the following problems: since the connecting port 43 (air port) provided at the end of the rod side of the cylinder portion 3 is a curved shape having a transverse hole in the reciprocating direction of the piston, hole processing is performed from two directions, so the processing is complicated, and since it is necessary to ensure space for processing the transverse hole, the size of the piston in the reciprocating direction is increased.

[0012] In addition, since the aperture size of the horizontal hole is limited by the wall thickness of the cylinder, it must be set to a diameter size that converges within the wall thickness of the cylinder. Depending on the wall thickness of the cylinder, there is a concern that it will be difficult to ensure sufficient air intake and discharge volume, and as a result, it will be difficult to obtain the desired cylinder response speed.

[0013] Furthermore, in the case of a double-acting type, if the assembly of an external connection device such as a speed controller relative to the two connecting ports 43 provided at the end of the rod side and the end of the head side of the cylinder 3 is taken into consideration, it is desirable to make the connecting port 43 on the rod side as close to the rod side as possible and thereby increase the interval between the two connecting ports 43.

[0014] However, such a demand for improved assemblability of external connection devices is a demand that is contrary to the demand for compactness of the device, and it is difficult to satisfy both the demand for improved assemblability of external connection devices and the demand for compactness of the device.

[0015] The present invention has been developed to solve previous problems, and its purpose is to provide an air-driven actuator and a method for manufacturing an air-driven actuator that is easier to process, easier to obtain a desired cylinder response speed, and can be compact, especially in a double-acting type, which can achieve compactness while widening the distance between two air ports.

[0016] Means used to solve problems

[0017] In order to achieve the above-mentioned purpose, the invention related to technical solution 1 is an air-driven actuator having a cylinder, wherein the cylinder is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating space is formed inside in which the piston reciprocates by sucking and discharging air through the air port, the cylinder having an enlarged diameter portion, and the enlarged diameter portion is provided by enlarging the inner diameter in the area adjacent to the piston rod guide in the reciprocating direction of the piston; the air port provided at the end of the rod side has a lower hole, and the lower hole includes: a through portion, which is penetrated into the cylinder by overlapping a portion of the rod side of the lower hole in the radial direction with the enlarged diameter portion in the reciprocating direction of the piston and connecting with the enlarged diameter portion; and a non-through portion, which is not penetrated into the cylinder by not overlapping a portion of the lower hole in the radial direction with the enlarged diameter portion.

[0018] The invention related to technical solution 2 is an air-driven actuator, wherein the enlarged diameter portion is provided to gradually enlarge the inner diameter from the pull-out side toward the pull-in side of the piston rod in the reciprocating direction of the piston.

[0019] The invention related to technical solution 3 is an air-driven actuator having a housing, wherein the housing has a driving space provided with a rotation conversion mechanism that converts the reciprocating motion of the piston into rotational motion and transmits it to the output shaft and is connected to the cylinder from the end of the rod side; the housing is mounted on the valve for use in a state where the output shaft is connected to the valve rod.

[0020] The invention related to technical solution 4 is a method for manufacturing an air-driven actuator, wherein the air-driven actuator has a cylinder, wherein the cylinder is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating space is formed inside the cylinder in which the piston reciprocates by sucking and discharging air through the air port. The method for manufacturing the air-driven actuator comprises: a step of providing a cylinder having an enlarged diameter portion, wherein the enlarged diameter portion enlarges the inner diameter in an area adjacent to the piston rod guide in the reciprocating direction of the piston of the air-driven actuator; and a step of forming a hole as a lower hole of the air port at the end on the rod pulling-out side, wherein the hole comprises: a through portion, which is passed into the cylinder by overlapping a portion of the rod side of the hole in the radial direction with the enlarged diameter portion in the reciprocating direction of the piston and connecting with the enlarged diameter portion; and a non-through portion, which is not passed into the cylinder by not overlapping a portion of the hole in the radial direction with the enlarged diameter portion.

[0021] Effects of the Invention

[0022] According to the invention of the relevant technical scheme 1, there is a cylinder, which is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating space is formed inside in which the piston reciprocates by sucking and discharging air through the air port, and the cylinder has an enlarged diameter portion, and the enlarged diameter portion is provided by enlarging the inner diameter in the area adjacent to the piston rod guide in the reciprocating direction of the piston; the air port provided at the end of the rod side has a lower hole, and the lower hole includes: a through portion, which is penetrated into the cylinder by overlapping a part of the rod side of the lower hole in the radial direction with the enlarged diameter portion in the reciprocating direction of the piston and connecting with the enlarged diameter portion; and a non-through portion, which is not penetrated into the cylinder by not overlapping a part of the lower hole in the radial direction with the enlarged diameter portion.

[0023] In this way, the air port is not directly passed through the cylinder, but a radial portion of the lower hole is connected to the enlarged diameter portion and the rest is set as a non-penetrated portion, thereby eliminating the need to provide an additional hole for passing the air port through the cylinder.

[0024] If the piston reciprocating along the inner wall of the cylinder passes through the through hole of the air port provided on the cylinder wall, the piston and the sealing component for the piston may be damaged, so it is necessary to provide a through hole outside the stroke range of the piston, but the cylinder becomes larger by the distance.

[0025] According to the invention of claim 1, as described above, the air port can be connected to the cylinder without separately providing a through hole that directly communicates with the inside of the cylinder, so that damage to the piston and the piston seal member can be avoided while also preventing the cylinder from being enlarged.

[0026] In addition, according to the invention of claim 1, since the air port communicates with the inside of the cylinder via the enlarged diameter portion instead of the lateral hole, the complicated processing of the lateral hole is no longer required and the processing of the air port becomes easy.

[0027] Furthermore, by adjusting the overlap between the enlarged diameter portion and the lower hole, it is possible to ensure a sufficient amount of air intake and discharge.

[0028] Furthermore, since no transverse hole is provided, the air port can be used as the stroke area of ​​the piston except for the portion radially overlapping with the enlarged diameter portion, so the size of the cylinder can be reduced as a whole, and in the case of a double-acting type, the air port provided at the end of the rod side of the cylinder can be provided away from the air port provided at the end of the head side of the cylinder.

[0029] Therefore, processing is easy, a desired cylinder speed is easily obtained, and compactness can be achieved. In particular, in a double-acting type, compactness can be achieved while increasing the interval between the two air ports.

[0030] According to the invention of technical solution 2, the enlarged diameter portion is provided to gradually enlarge the inner diameter from the pulling-out side toward the pulling-in side of the piston rod in the reciprocating motion direction of the piston. Thus, when the cylinder is formed using a mold, it can be easily formed compared to the enlarged diameter portion provided as a groove of a certain depth.

[0031] In addition, since the invention of technical solution 2 also gradually expands from the edge side of the expanded diameter portion toward the inner diameter side, the diameter of the connecting portion can be easily adjusted by adjusting the depth of the lower hole, and the air intake and discharge volume can also be easily set.

[0032] According to the invention of technical solution 3, there is a shell, which forms a driving space for a rotation conversion mechanism that converts the reciprocating motion of the piston into rotational motion and transmits it to the output shaft, and is connected to the cylinder from the end of the rod side; the shell is mounted on the valve for use in a state where the output shaft set in the rotation conversion mechanism is connected to the valve rod; thereby, the reciprocating motion of the piston in the compact cylinder is converted into the rotational movement of the valve rod via the rotation conversion mechanism, and the valve is opened and closed, so it can be used as an actuator of a valve that can be compactly assembled relative to the valve.

[0033] According to the invention of technical solution 4, there is a method for manufacturing an air-driven actuator, wherein the air-driven actuator has a cylinder, wherein the cylinder is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating space is formed inside the cylinder in which the piston reciprocates by sucking and discharging air through the air port. In the method for manufacturing the air-driven actuator, it includes: a step of providing an enlarged diameter portion in the cylinder, wherein the enlarged diameter portion enlarges the inner diameter in the area adjacent to the piston rod guide in the reciprocating direction of the piston; and a step of forming a hole as a lower hole of the air port at the end of the rod side, wherein the hole includes: a through portion, which is passed into the cylinder by overlapping a radial portion of the hole with the enlarged diameter portion in the reciprocating direction of the piston and connecting with the enlarged diameter portion; and a non-through portion, which is not passed into the cylinder by not overlapping a radial portion of the hole with the enlarged diameter portion.

[0034] Thus, for example, when a method of molding the cylinder using a mold such as casting is applied, the cylinder is formed in advance in such a manner that an enlarged diameter portion is formed, and then only a predetermined lower hole is formed in such a manner that a portion is communicated with the enlarged diameter portion, so that the air port can be formed simply and at low cost. In particular, since the air port communicates with the inside of the cylinder via the enlarged diameter portion instead of the lateral hole, there is no need for complicated processing of the lateral hole, and the processing of the air port becomes easy.

[0035] Furthermore, by adjusting the overlap between the enlarged diameter portion and the lower hole, it is possible to ensure a sufficient amount of air intake and discharge.

[0036] Furthermore, since no transverse hole is provided, the air port can serve as the stroke area of ​​the piston except for the portion radially overlapping with the enlarged diameter portion, so the size of the cylinder can be reduced as a whole, and in the case of a double-acting type, the air port provided at the end of the rod side of the cylinder can be provided away from the air port provided at the end of the head side of the cylinder.

[0037] Therefore, processing is easy, a desired cylinder speed is easily obtained, and compactness can be achieved. In particular, in a double-acting type, compactness can be achieved while increasing the interval between the two air ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a perspective view of an air-driven actuator according to an embodiment of the present invention.

[0039] Figure 2 It is a cross-sectional view of an air-driven actuator with the piston head at the end of stroke position on the cylinder head side.

[0040] Figure 3 It is a cross-sectional view of an air driven actuator with the piston head at the end of stroke on the rod side of the cylinder.

[0041] Figure 4 yes Figure 3 An enlarged perspective view of the periphery of the enlarged diameter portion of the air-driven actuator shown.

[0042] Figure 5 This is a view of an opening viewed from the inner wall surface side of the cylinder, the opening being a portion where a lower hole of an air port provided at an end portion on the rod side communicates with the enlarged diameter portion.

[0043] Figure 6 It is a perspective view of a driving actuator in a state where a speed controller is attached to two air ports and the actuator is assembled to a valve, with a portion cut away. DETAILED DESCRIPTION

[0044] Embodiments of an air-driven actuator and a method for manufacturing an air-driven actuator according to the present invention will be described in detail with reference to the drawings.

[0045] Figure 1 It is a perspective view of the air-driven actuator 1 according to the embodiment of the present invention. Figure 2 1 is a cross-sectional view of the air-driven actuator with the piston head 22 at the stroke end position on the head side of the cylinder 10 . Figure 3 1 is a cross-sectional view of the air-driven actuator 1 with the piston head 22 at the stroke end position on the rod side in the cylinder 10 . Figure 4 yes Figure 3 An enlarged perspective view of the periphery of the enlarged diameter portion 14 of the air-driven actuator 1 is shown. Figure 5 The figure shows the opening 15ac from the inner wall surface 12a side of the cylinder 10, and the opening 15ac is a portion where the lower hole 15a of the air port 15 provided at the end 10a on the rod side communicates with the enlarged diameter portion 14. Figure 6 It is a partially cutaway perspective view of the drive-type actuator 1 in a state where the speed controller 200 is attached to the two air ports 15 and 16 and the actuator is assembled to the valve 100 .

[0046] The air-driven actuator 1 according to the embodiment of the present invention is one of the driving sources for opening and closing a valve (not shown), and is a double-acting type that utilizes air pressure for both the opening and closing operations of the valve.

[0047] The air-driven actuator 1 comprises: a cylinder 10; a piston 20 that reciprocates by means of air pressure; a housing 30 that is provided with a rotation conversion mechanism 60 that converts the reciprocating motion of the piston 20 into a rotational motion and is connected to the cylinder 10; a housing cover 40 that closes an opening at one end of the housing 30; and a piston rod guide 50 that guides the piston rod 21 of the piston 20.

[0048] The cylinder 10 , the housing 30 , and the housing cover 40 are connected to each other in the axial direction so as to be concentric with the axis of the piston rod 21 , thereby constituting the outer contour of the air-driven actuator 1 with the axial direction of the piston rod 21 as the longitudinal direction.

[0049] In the present embodiment, the cylinder 10, the housing 30, and the housing cover 40 are manufactured by casting, but other manufacturing methods may be used or various manufacturing methods may be combined. For example, the inside of the cast cylinder 10 may be subjected to cutting.

[0050] (About cylinder 10)

[0051] When the end of the cylinder 10 on the side where the piston rod 21 is pulled out in the reciprocating direction of the piston 20 is set as the end 10a on the rod side, and the end on the side where the piston rod 21 is pulled in is set as the end 10b on the head side, a piston reciprocating space 13 is formed inside the cylinder 10, in which air is sucked in and discharged through two air ports 15 and 16 set at each end 10a and 10b, so that the piston 20 reciprocates.

[0052] The cylinder 10 has a peripheral side wall 12 and a blocking wall 11 provided at an end 10 b on the head side, and has a substantially cylindrical shape with an end 10 a on the rod side facing the blocking wall 11 being open.

[0053] The cylinder 10 has one air port 15 (hereinafter referred to as “rod-side air port”) at the end 10a on the rod side and another air port 16 (hereinafter referred to as “head-side air port”) at the end 10b on the head side.

[0054] The two air ports 15 and 16 are formed by machining lower holes 15 a and 16 a in the peripheral side wall 12 and then machining threaded holes 15 b and 16 b.

[0055] In addition, in this embodiment, if Figure 1 As shown, the rod-side air port 15 is provided so as to partially overlap with the flange portion 10 aa of the cylinder 10 .

[0056] In this embodiment, external connection equipment such as a speed controller (not shown) is screwed into the screw holes 15b and 16b and mounted in the two air ports 15 and 16. The two air ports 15 and 16 are connected to the direction switching valve via air pipes connected to the speed controller.

[0057] At the two air ports 15, 16, external equipment is installed, e.g. Figure 6 The installation space of the external device is determined by the distance between the air ports 15 and 16. For example, when the speed controller is installed by screwing into the threaded holes provided in the air ports 15 and 16, the rectangular parallelepiped speed controller shown in the figure is rotated and screwed in.

[0058] Therefore, when screwing into each of the air ports 15 and 16, it is necessary to grasp the speed controller and rotate it, and the area does not simply need to have a space to accommodate the device, but requires a margin.

[0059] Thus, the two air ports 15 and 16 are preferably spaced as far apart from each other as possible.

[0060] In the present embodiment, by connecting the lower hole 15a of the air port 15 with the enlarged diameter portion 14 provided in the cylinder 10, air can be supplied from the air port 15 to the cylinder 10, but the enlarged diameter portion 14 is provided in an area adjacent to the piston rod guide 50, so the air port 15 connected thereto can be provided at a position as close as possible to the piston rod 21 side (for example, partially or completely overlapping with the flange portion 10aa).

[0061] Therefore, the air port 15 usually has to be provided at a midway position of the wall surface of the cylinder 10 in order to communicate with the inside of the cylinder 10 , and it is difficult to sufficiently separate the two air ports 15 and 16 .

[0062] On the other hand, in the present embodiment, the distance between the air ports 15 and 16 can be made as far as possible, which is advantageous for mounting external devices such as the speed controller 200 .

[0063] Furthermore, the cylinder 10 has an enlarged diameter portion 14 which is provided by enlarging the inner diameter in a region adjacent to the piston rod guide 50 in the reciprocating direction of the piston 20 .

[0064] The enlarged diameter portion 14 is a groove provided along the inner circumferential direction on the inner wall surface 12 a of the peripheral side wall 12 so as to gradually increase the inner diameter from the withdrawal side toward the insertion side of the piston rod 21 in the reciprocating direction of the piston 20 .

[0065] In this embodiment, the cylinder 10 and the housing 30 are connected via flanges 10aa and 30aa provided at the respective ends 10a and 30a. Therefore, the thickness of the peripheral wall 12 of the end 10a on the rod side of the cylinder 10 plus the thickness of the flange 10aa is thicker than the periphery.

[0066] That is, a flange portion 10aa that protrudes toward the outer diameter side from a portion of the peripheral side wall 12 other than the end portion 10a is provided at the end portion 10a on the rod side of the peripheral side wall 12 of the cylinder 10 .

[0067] The enlarged diameter portion 14 is provided at the flange portion 10aa constituting the thick wall portion, and is provided so that the outermost diameter position thereof is located on the outer diameter side of the outer wall surface 12b of the peripheral wall 12 of the cylinder 10 other than the flange portion 10aa.

[0068] That is, the enlarged diameter portion 14 is provided on the peripheral side wall 12 of the cylinder 10 by effectively utilizing the portion where the wall thickness is increased by the flange portion 10 aa of the cylinder 10 .

[0069] Furthermore, by providing the rod side air port 15 with the lower hole 15 a communicating with the enlarged diameter portion 14 as described later, it is not necessary to provide a through hole for supplying air into the cylinder 10 in the peripheral wall 12 of the cylinder 10 other than the flange portion 10 aa .

[0070] Thus, in the present embodiment, the enlarged diameter portion 14 is provided at the flange portion 10aa of the cylinder 10 so as not to interfere with the normal reciprocating motion (stroke) range of the peripheral side wall 12 of the cylinder 10 other than the flange portion 10aa, that is, the piston head 22. As a result, the size of the cylinder 10 is prevented from increasing due to the provision of the enlarged diameter portion 14.

[0071] The enlarged diameter portion 14 may be provided by enlarging the inner diameter in a region adjacent to the piston rod guide 50 in the reciprocating direction of the piston 20 , and may be, for example, a groove having a constant depth provided on the inner wall surface 12 a of the peripheral side wall 12 .

[0072] Furthermore, the rod-side air port 15 has a lower hole 15 a communicating with the enlarged diameter portion 14 .

[0073] The lower hole 15a includes: a through portion 15aa, which penetrates into the cylinder 10 by overlapping a radial portion of the lower hole 15a with the enlarged diameter portion 14 in the reciprocating motion direction of the piston 20 and communicating with the enlarged diameter portion 14; and a non-through portion 15ab, which does not penetrate into the cylinder 10 by not overlapping a radial portion of the lower hole 15a with the enlarged diameter portion 14.

[0074] Since the non-penetrating portion 15ab of the lower hole 15a does not penetrate the peripheral side wall 12 of the cylinder 10, Figure 2 to Figure 4As shown, the inner side of the lower hole 15a becomes a region A of the inner wall surface 12a where the piston head 22 can slide.

[0075] The depth of the non-penetrating portion 15ab is the same as or shallower than the outer wall surface 12b of the circumferential side wall 12 of the cylinder 10 other than the flange portion 10aa. Here, the so-called "the depth of the non-penetrating portion 15ab is the same as or shallower than the outer wall surface 12b of the circumferential side wall 12 of the cylinder 10" means, for example, that the uniform portion of the lower hole 15a, for example, the portion other than the portion that is reduced in diameter toward the front end formed when the lower hole is drilled, is the same as or shallower than the outer wall surface 12b of the circumferential side wall 12 of the cylinder 10. By forming the non-penetrating portion 15ab in this way, even if the lower hole 15a is provided, the strength of the circumferential side wall 12 of the cylinder 10 can be sufficiently maintained, and the movement of the piston 20 is not hindered.

[0076] In addition, the lower hole 15a can overlap the enlarged diameter portion 14 in the reciprocating direction of the piston 20 in a radial direction, so that the rod side air port 15 can be set at a position maximally close to the end 10a on the rod side of the cylinder 10, that is, close to the piston rod guide 50.

[0077] Furthermore, in this embodiment, since the enlarged diameter portion 14 is provided at the flange portion 10aa, that is, the portion originally outside the reciprocating range of the piston 20, the distance from the head-side air port 16 can be increased without increasing the dimension of the piston 20 in the reciprocating direction.

[0078] Furthermore, the through portion 15aa of the rod side air port 15 is as shown in FIG. Figure 4 and Figure 5 As shown, the inner wall surface 12 a of the cylinder 10 including the inclined surface 14 a of the enlarged diameter portion 14 penetrates to form an opening.

[0079] In other words, the lower hole 15 a penetrates the inner wall surface 12 a of the cylinder 10 including the surfaces 14 a and 14 b that form the enlarged diameter portion 14 and face in different directions, to form an opening 15 ac.

[0080] Therefore, the opening area of ​​the opening 15ac can be adjusted by the overlap between the enlarged diameter portion 14 and the lower hole 15a.

[0081] Furthermore, since the opening 15ac is formed across a plurality of surfaces in different directions, the opening area can be increased compared to the case where the opening 15ac is formed on one surface.

[0082] The opening area of ​​the opening 15ac can correspond to various specifications by changing the shape of the enlarged diameter portion 14 or the shape of the lower hole 15a, for example, in addition to the overlap between the enlarged diameter portion 14 and the lower hole 15a in the radial and depth directions.

[0083] Therefore, the opening area of ​​the opening 15ac can be made larger than the opening area formed by the conventional lateral hole whose size is determined by the wall thickness of the peripheral wall 12 of the cylinder 10, and can correspond to various opening shapes.

[0084] Furthermore, the opening area of ​​the opening 15ac is adjusted to obtain a desired response speed of the cylinder.

[0085] More specifically, the opening area of ​​the opening 15 ac is adjusted so as to be equal to or larger than the hole cross-sectional area of ​​the air pipe connected to the rod-side air port 15 .

[0086] In this way, since the rod-side air port 15 is formed by connecting the enlarged diameter portion 14 set in the cylinder 10 with the lower hole 15a, air and the like can be sucked in and discharged relative to the cylinder 10 in a linear manner compared to the case of setting a horizontal hole. In addition, since its opening 15ac is also adjusted to an opening area that obtains the desired cylinder response speed, the responsiveness for opening and closing the valve is also excellent.

[0087] For example, if the inside of the cylinder 10 is connected to the outside by using only the enlarged diameter portion 14, a small air port having only the through portion 15aa communicating with the enlarged diameter portion 14 may be provided. However, this may result in insufficient air supply to the cylinder 10.

[0088] On the other hand, according to the present embodiment, by providing the rod-side air port 15 having a relatively large diameter including the through portion 15aa and the non-through portion 15ab, it is possible to connect an air pipe capable of supplying a sufficient amount of air.

[0089] Furthermore, by setting the opening 15 ac to have an appropriate opening area, the air supplied from the air pipe can be sufficiently supplied into the cylinder 10 .

[0090] Moreover, the rod side air port 15 has a sufficiently large diameter, has a through portion 15aa on the rod side, and has a non-through portion 15ab on the head side away from the rod side than the through portion 15aa, so that there is no through hole that interferes with the stroke area of ​​the piston 20.

[0091] As a result, the overall size of the air-driven actuator 1 can be made compact, and the response speed, which is originally a performance that is contrary to compactness, can be maintained sufficiently high.

[0092] (About Piston 20)

[0093] The piston 20 has a piston rod 21 and a piston head 22 provided at one end of the piston rod 21 .

[0094] The piston head 22 reciprocates integrally with the piston rod 21 by the intake and discharge of air through the two air ports 15 and 16 .

[0095] The piston head 22 has a sealing O-ring 22 a made of an elastic material attached to the peripheral surface thereof in order to prevent air from moving between the peripheral surface of the piston head 22 and the inner wall surface 12 a of the cylinder 10 .

[0096] Therefore, the piston head 22 partitions the inside of the cylinder 10 into two air chambers and reciprocates in the axial direction while the sealing O-ring 22 a is in sliding contact with the inner wall surface 12 a of the cylinder 10 .

[0097] Then, the stroke end position of the piston head 22 on the rod side in the cylinder 10 is adjusted so as to be located in the vicinity of the enlarged diameter portion 14 .

[0098] That is, the piston head 22 can be a region A (see FIG. 1 ) of the inner wall surface 12a of the non-penetrating portion 15ab of the lower hole 15a of the rod-side air port 15. Figure 2 , Figure 3 ) is included in the reciprocating motion range of the piston head 22 and reciprocates.

[0099] In addition, the stroke range of the piston 20 is limited by stoppers 17 and 41 provided on the blocking wall 11 of the cylinder 10 and the housing cover 40 , respectively, so as to be able to abut against the respective ends of the piston rod 21 .

[0100] (About the housing 30)

[0101] The housing 30 has a driving space 31 in which a rotation conversion mechanism 60 is provided for converting the reciprocating motion of the piston 20 into a rotational motion and transmitting the rotational motion to the output shaft, and is connected to the cylinder 10 from the end 10 a on the rod side.

[0102] The rotation conversion mechanism 60 arranged in the housing 30 adopts a so-called scotch yoke mechanism, which has a scotch yoke 62 that engages with a pin 61 protruding in the radial direction outward of the piston rod 21, and a shaft 63 connected to the scotch yoke 62 by means of a key 64 and driven to rotate as an output shaft.

[0103] That is, the rotation conversion mechanism 60 converts the reciprocating motion of the piston 20 into the rotational motion of the shaft 63 via the Scotch yoke 62 .

[0104] The shaft 63 extends in an axial direction perpendicular to the piston rod 21 and is connected to a valve rod (not shown). The valve body such as a butterfly valve or a ball valve is opened and closed by the rotation of the valve rod.

[0105] In addition, in the present embodiment, a scotch yoke type is adopted as the rotation conversion mechanism 60 , but the present invention is not limited to this, and for example, a rack and pinion type mechanism may be adopted.

[0106] (Regarding the housing cover 40)

[0107] The housing cover 40 has a guide portion for axially guiding the piston rod 21 that freely reciprocates relative to the housing 30 , and is attached to the housing 30 from the end opening side of the housing 30 .

[0108] (Regarding the piston rod guide 50)

[0109] The piston rod guide 50 partitions the piston reciprocating space 13 and the driving space 31 and guides the piston rod 21 .

[0110] The peripheral edge of the piston rod guide 50 is clamped and fixed between the cylinder 10 and the housing 30, more specifically, between the flange portion 10aa provided at the end 10a on the rod side of the cylinder 10 and the flange portion 30aa provided at the end 30a of the housing 30, while overlapping with the sealing member 52.

[0111] Furthermore, the piston rod guide 50 includes a through hole 51 through which the piston rod 21 is inserted to be reciprocatable, and guides the piston rod 21 in the axial direction.

[0112] Next, the operation of the air-driven actuator 1 will be described.

[0113] Here, a series of reciprocating motions of the piston 20 will be described. That is, a series of motions of the piston 20 from a state where the piston rod 21 is pulled into the cylinder 10 to a state where the piston rod 21 is pulled out of the cylinder 10 and then back to a state where the piston rod 21 is pulled into the cylinder 10 will be described.

[0114] First, if Figure 2 As shown, if air is supplied to the cylinder 10 through the head side air port 16 when the piston rod 21 is pulled into the cylinder 10, that is, the piston head 22 is at the end position of the stroke on the head side of the cylinder 10, the piston head 22 receives the thrust brought by the air and begins to move toward the end 10a on the rod side of the cylinder 10.

[0115] In addition, when the piston head 22 is at the stroke end position on the head side of the cylinder 10, the piston rod 21 hits the stopper 17 provided on the blocking wall 11 of the cylinder 10, and the piston head 22 stops at a position away from the blocking wall 11 of the cylinder 10.

[0116] Therefore, when the piston head 22 is at the stroke end position on the head side of the cylinder 10, air flows into the air chamber between the sealing wall 11 and the piston head 22 through the head side air port 16, generating a thrust that moves the piston head 22 toward the stroke end position on the rod side of the cylinder 10.

[0117] Then, if Figure 3As shown, the piston head 22 moves to a state where the piston rod 21 is pulled out of the cylinder 10 , that is, to a stroke end position on the rod side in the cylinder 10 .

[0118] At this time, the air in the cylinder 10 is discharged to the outside through the rod-side air port 15. More specifically, the air in the cylinder 10 is discharged to the outside from the enlarged diameter portion 14 through the rod-side air port 15.

[0119] The piston head 22 moves to a position near the enlarged diameter portion 14 while the sealing O-ring 22a installed on the circumferential surface is in sliding contact with the inner wall surface 12a of the cylinder 10. At this time, the piston head 22 passes through the lower hole 15a and becomes a region A of the inner wall surface 12a that is not penetrated (see Figure 2 , Figure 3 ).

[0120] When the piston head 22 is at the stroke end position on the rod side, the piston rod 21 abuts against the stopper 41 provided on the housing cover 40 , whereby the piston head 22 stops at a position away from the enlarged diameter portion 14 of the cylinder 10 .

[0121] Then, as air flows into the cylinder 10 through the rod-side air port 15 , thrust is generated to move the piston head 22 toward the stroke end position on the head side, and the piston head 22 starts to move toward the stroke end position on the head side.

[0122] Here, the air supplied through the rod-side air port 15 flows into the air chamber between the piston rod guide 50 and the piston head 22 through the enlarged diameter portion 14 .

[0123] At this time, the air in the cylinder 10 is discharged to the outside through the head-side air port 16 .

[0124] Then, the air driven actuator 1 is as follows Figure 2 As shown, the piston rod 21 is pulled into the cylinder 10 , that is, the piston head 22 moves to the stroke end position on the head side, and a series of reciprocating actions of the air-driven actuator 1 are completed.

[0125] Next, a method for manufacturing the air-driven actuator 1 will be described.

[0126] In addition, a method for manufacturing the cylinder 10 will be described here.

[0127] First, the cylinder 10 is provided with an enlarged diameter portion 14 in which the inner diameter is enlarged in a region around the end portion 10 a on the rod side.

[0128] The step of providing the enlarged diameter portion 14 with respect to the cylinder 10 is included in the step of molding the cylinder 10 by casting. That is, in this step, the cylinder 10 having the enlarged diameter portion 14 is molded by casting.

[0129] In addition, a portion corresponding to the enlarged diameter portion 14 can be provided in the sand mold for casting the cylinder 10, and the cylinder 10 having the enlarged diameter portion 14 can be formed by a general sand casting procedure. That is, there is almost no work load caused by providing the enlarged diameter portion 14 in the cylinder 10.

[0130] Here, in the present embodiment, since the enlarged diameter portion 14 is provided to gradually enlarge the inner diameter from the pull-out side toward the pull-in side of the piston rod 21 in the reciprocating motion direction of the piston 20, in the case of sand casting, when pouring the molten liquid, it flows on the inclined surface of the sand mold corresponding to the enlarged diameter portion 14, so it is difficult to become turbulent, and the poured liquid flows smoothly into the sand mold, so that sand peeling can be prevented. As a result, it is difficult to produce quality defects such as sand inclusions, and processing is easy.

[0131] In addition, in the case of casting using a mold, the molten metal also flows on the inclined surface of the mold corresponding to the enlarged diameter portion 14 during pouring, so it is difficult to cause turbulence, and the poured liquid flows smoothly into the mold, so it is difficult to cause quality defects and easy processing.

[0132] The enlarged diameter portion 14 may also be formed by cutting the inside of the cast cylinder 10. By combining casting and cutting in this way, the enlarged diameter portion 14 can be formed in various shapes corresponding to the air intake and discharge amounts.

[0133] Next, the rod-side air port 15 and the head-side air port 16 are processed.

[0134] In this step, the lower holes 15 a and 16 a are processed, and then the threaded holes 15 b and 16 b are processed, so that the rod-side air port 15 and the head-side air port 16 are formed.

[0135] The rod side air port 15 is formed by processing a hole including a through portion 15aa and a non-through portion 15ab as a lower hole 15a, and then processing a threaded hole 15b. The through portion 15aa penetrates into the cylinder 10 by overlapping a portion of the rod side of the hole in the radial direction with the enlarged diameter portion 14 in the reciprocating motion direction of the piston 20 and communicating with the enlarged diameter portion 14, and the non-through portion 15ab does not penetrate into the cylinder 10 by not overlapping a portion of the hole in the radial direction with the enlarged diameter portion 14.

[0136] In this way, the rod side air port 15 forms a flow path for air to penetrate into the cylinder 10 via the enlarged diameter portion 14 while leaving the non-penetrated portion 15ab that does not penetrate into the cylinder 10 by forming the lower hole 15a at a position partially overlapping the enlarged diameter portion 14 in the radial direction.

[0137] On the other hand, the head-side air port 16 is formed by machining a lower hole 16 a penetrating into the cylinder 10 and then machining a threaded hole 16 b.

[0138] According to the air-driven actuator 1 of the embodiment of the present invention, the cylinder 10 has an enlarged diameter portion 14, which is provided by enlarging the inner diameter in the area adjacent to the piston rod guide 50 in the reciprocating direction of the piston 20; the rod-side air port 15 provided at the end 10a on the rod side has a lower hole 15a, and the lower hole 15a includes: a through portion 15aa, which penetrates into the cylinder 10 by overlapping a radial portion of the lower hole 15a with the enlarged diameter portion 14 in the reciprocating direction of the piston 20 and communicating with the enlarged diameter portion 14; and a non-penetrated portion 15ab, which does not penetrate into the cylinder 10 by not overlapping a radial portion of the lower hole 15a with the enlarged diameter portion 14.

[0139] In this way, the rod side air port 15 is not allowed to directly penetrate into the cylinder 10, but a radial portion of the lower hole 15a is connected to the enlarged diameter portion 14 and the rest of the portion is set as a non-penetrated portion, thereby eliminating the need to provide an additional hole for allowing the rod side air port 15 to penetrate into the cylinder 10.

[0140] If the piston 20 reciprocating along the inner wall surface 12a of the cylinder 10 passes through the through hole of the rod side air port 15 provided on the wall surface of the cylinder 10, there is a possibility of damage to the piston 20 and the sealing O-ring 22a serving as a sealing component for the piston, so it is necessary to provide a through hole outside the stroke range of the piston 20, but this causes the cylinder 10 to become larger by the amount of this distance.

[0141] As described above, the air-driven actuator 1 according to the embodiment of the present invention can connect the rod-side air port 15 to the cylinder 10 without separately providing a through hole that directly connects to the inside of the cylinder 10, thereby avoiding damage to the piston 20 and the sealing O-ring 22a while also avoiding an increase in the size of the cylinder 10.

[0142] Furthermore, since the rod-side air port 15 communicates with the inside of the cylinder 10 via the enlarged diameter portion 14 instead of the lateral hole, complicated processing of the lateral hole is no longer required and processing of the rod-side air port 15 becomes easy.

[0143] Furthermore, by adjusting the overlap between the enlarged diameter portion 14 and the lower hole 15 a , it is possible to ensure a sufficient amount of air intake and discharge.

[0144] Furthermore, corresponding to not providing a transverse hole, the rod-side air port 15 can serve as a stroke area of ​​the piston 20 except for the portion overlapping with the enlarged diameter portion 14 in the radial direction, so the size of the cylinder 10 can be reduced as a whole, and in the case of a double-acting type, the rod-side air port 15 of the cylinder 10 can be provided away from the head-side air port 16 of the cylinder 10.

[0145] Therefore, processing is easy, a desired cylinder speed is easily obtained, and compactness can be achieved. In particular, in a double-acting type, compactness can be achieved while increasing the interval between the two air ports.

[0146] Moreover, according to the air-driven actuator 1 of the embodiment of the present invention, by increasing the interval between the two air ports 15 and 16, when external connection devices such as a speed controller are screwed into the threaded holes 15b and 16b relative to each air port 15 and 16 for installation, the external connection devices will not interfere with each other and become obstacles, so the external connection devices can be easily assembled relative to each air port 15 and 16.

[0147] Furthermore, according to the air-driven actuator 1 of the embodiment of the present invention, the enlarged diameter portion 14 is provided so as to gradually enlarge the inner diameter from the withdrawal side toward the withdrawal side of the piston rod 21. Thus, for example, in the case of sand casting, the molten liquid flows on the inclined surface of the sand mold corresponding to the enlarged diameter portion 14 during liquid pouring, so that turbulence is less likely to occur, and sand peeling can be prevented. As a result, quality defects such as sand inclusion are less likely to occur, and the enlarged diameter portion can be easily formed compared to a groove of a certain depth.

[0148] Furthermore, according to the air-driven actuator 1 of the embodiment of the present invention, since the enlarged diameter portion 14 also gradually expands from the edge side of the enlarged diameter portion 14 toward the inner diameter side, the diameter of the connecting portion can be easily adjusted by adjusting the depth of the lower hole 15a, and the air intake and discharge amount can also be easily set.

[0149] In addition, according to the air-driven actuator 1 of the embodiment of the present invention, there is a housing 30, which has a driving space 31 provided with a rotation conversion mechanism 60 that converts the reciprocating motion of the piston 20 into rotational motion and transmits it to the shaft 63, and is connected to the cylinder 10 from the end 10a on the rod side; it is mounted on the valve for use in a state where the shaft 63 is connected to the valve rod; thereby, the reciprocating motion of the piston 20 in the compact cylinder 10 is converted into the rotational motion of the valve rod via the rotation conversion mechanism 60, and the valve is opened and closed, so it can be used as a valve actuator that can be compactly assembled relative to the valve.

[0150] According to an embodiment of the present invention, a method for manufacturing an air-driven actuator includes: a step of providing a cylinder 10 having an enlarged diameter portion 14, wherein the enlarged diameter portion 14 has an inner diameter enlarged in a region adjacent to a piston rod guide 50 in a reciprocating direction of a piston 20; and a step of forming a lower hole 15a as a lower hole 15a of a rod-side air port 15, wherein the lower hole 15a includes: a through portion 15aa, which is passed through into the cylinder 10 by overlapping a portion of the lower hole 15a on the rod side in a radial direction with the enlarged diameter portion 14 in a reciprocating direction of the piston 20 and communicating with the enlarged diameter portion 14; and a non-through portion 15ab, which is not passed through into the cylinder 10 by not overlapping a portion of the lower hole 15a in a radial direction with the enlarged diameter portion 14.

[0151] Thus, for example, when the cylinder 10 is formed using a mold such as casting, the cylinder 10 is formed in advance so as to form the enlarged diameter portion 14, and then the predetermined lower hole 15a is formed so as to be partially connected to the enlarged diameter portion 14, so that the rod-side air port 15 can be formed simply and at low cost. In particular, since the rod-side air port 15 is connected to the inside of the cylinder 10 via the enlarged diameter portion 14 instead of the lateral hole, the complicated processing of the lateral hole is no longer required, and the processing of the rod-side air port 15 becomes easy.

[0152] Furthermore, by adjusting the overlap between the enlarged diameter portion 14 and the lower hole 15 a , it is possible to ensure a sufficient amount of air intake and discharge.

[0153] Furthermore, since no transverse hole is provided, the rod-side air port 15 can be used as a stroke area of ​​the piston 20 except for the portion overlapping with the enlarged diameter portion 14 in the radial direction, so the size of the cylinder 10 can be reduced as a whole, and in the case of a double-acting type, the rod-side air port 15 of the cylinder 10 can be provided away from the head-side air port 16 of the cylinder.

[0154] Therefore, processing is easy, a desired cylinder speed is easily obtained, and compactness can be achieved. In particular, in a double-acting type, compactness can be achieved while increasing the interval between the two air ports.

[0155] As mentioned above, although embodiment of this invention is described in detail, this invention is not limited to the said embodiment, Various changes are possible within the range which does not deviate from the gist of this invention described in the claim of this invention.

[0156] In the above-mentioned embodiment, a double-acting type is adopted as the air-driven actuator 1, but as long as there is a cylinder 10 that sucks and discharges air through an air port 15 on the rod side and the piston 20 reciprocates, a single-acting type that utilizes the spring force of a spring in one of the reciprocating movements of the piston 20 may also be adopted.

[0157] For example, it can also be adopted in the pull-in type of the single-acting air-driven actuator 1. In addition, the so-called pull-in type is that when air is supplied from one air port 15 on the rod side, the piston rod 21 is pulled into the cylinder; when air is discharged from one air port 15, the piston rod 21 is pushed out of the cylinder by the spring force.

[0158] In the above embodiment, the pneumatic actuator 1 is exemplified as a driving source for opening and closing a valve, but the pneumatic actuator 1 may be used as a driving source other than a valve, for example, as a driving source for an industrial robot.

[0159] Description of Reference Numerals

[0160] 1 Air-driven actuator

[0161] 10 cylinders

[0162] 10a Rod side end

[0163] 10aa Flange

[0164] 10b End of the head side

[0165] 11 Blocking wall

[0166] 12 Sidewalls

[0167] 12a inner wall surface

[0168] 12b outer wall surface

[0169] 13 Piston reciprocating motion space

[0170] 14 Expanded diameter

[0171] 14a, 14b

[0172] 15 Rod side air port (air port)

[0173] 15a Lower hole

[0174] 15aa Through section

[0175] 15ab Unpenetrated

[0176] 15ac opening

[0177] 15b Threaded hole

[0178] 16 Head side air port (air port)

[0179] 16a Lower hole

[0180] 16b threaded hole

[0181] 17 Stopper

[0182] 20 Piston

[0183] 21 Piston rod

[0184] 22 Piston head

[0185] 22a Sealing O-ring

[0186] 30 Shell

[0187] 30a End

[0188] 30aa Flange

[0189] 31 Drive Space

[0190] 40 Housing cover

[0191] 41 Stopper

[0192] 50 Piston rod guide

[0193] 51 Through hole

[0194] 52 Sealing parts

[0195] 60 Rotational transformation mechanism

[0196] 61 Pins

[0197] 62 Scotch yoke

[0198] 63 Shaft (output shaft)

[0199] 100 valves

[0200] 200 Speed ​​Controller

Claims

1. An air-driven actuator comprising a cylinder, wherein the cylinder is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating motion space is formed inside the cylinder in which the piston reciprocates by sucking and discharging air through the air port, wherein the air-driven actuator is characterized in that: The cylinder has an enlarged diameter portion, which is provided by enlarging the inner diameter in a region adjacent to the piston rod guide in the reciprocating direction of the piston; The air port provided at the end portion on the aforementioned rod side has a lower hole comprising: A through portion, which penetrates into the aforementioned cylinder by overlapping a portion of the rod side of the lower hole in the radial direction with the aforementioned enlarged diameter portion in the reciprocating motion direction of the aforementioned piston and communicating with the aforementioned enlarged diameter portion; and a non-through portion, which does not penetrate into the aforementioned cylinder by not overlapping a portion of the lower hole in the radial direction with the aforementioned enlarged diameter portion.

2. The air-driven actuator according to claim 1, wherein: The enlarged diameter portion is provided so as to gradually enlarge the inner diameter from the withdrawal side toward the withdrawal side of the piston rod in the reciprocating motion direction of the piston.

3. The air-driven actuator according to claim 1 or 2, characterized in that: A housing having a driving space provided with a rotation conversion mechanism for converting the reciprocating motion of the piston into a rotational motion and transmitting the rotational motion to an output shaft and connected to the cylinder from an end portion on the rod side; The output shaft is connected to the valve stem and mounted on the valve for use.

4. A method for manufacturing an air-driven actuator, the air-driven actuator comprising a cylinder, the cylinder having at least one air port provided at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating motion space formed inside the cylinder in which the piston reciprocates by sucking and discharging air through the air port, the method for manufacturing the air-driven actuator being characterized in that: include: The step of providing the cylinder with an enlarged diameter portion having an enlarged inner diameter in a region adjacent to the piston rod guide in a reciprocating direction of the piston; and A step of forming a hole as a lower hole of the air port at the end of the aforementioned rod side, the hole comprising: a through portion, which is penetrated into the aforementioned cylinder by overlapping a portion of the rod side of the hole in the radial direction with the aforementioned enlarged diameter portion in the reciprocating motion direction of the aforementioned piston and communicating with the aforementioned enlarged diameter portion; and a non-through portion, which is not penetrated into the aforementioned cylinder by not overlapping a portion of the hole in the radial direction with the aforementioned enlarged diameter portion.

5. The air-driven actuator according to claim 1, wherein: A flange portion is provided at an end portion of the circumferential side wall of the cylinder on the rod side, the flange portion extending toward the outer diameter side from a portion of the circumferential side wall other than the end portion; The enlarged diameter portion is provided on the flange portion and is provided in such a manner that the outermost diameter position of the enlarged diameter portion is located on the outer diameter side of the outer wall surface of the peripheral side wall other than the flange portion; The non-penetrating portion of the lower hole of the air port has a depth that reaches a position substantially the same as or shallower than the outer wall surface of the peripheral side wall other than the flange portion.

6. The air-driven actuator according to claim 1, wherein: The through-portion is arranged on the rod side; The non-penetrating portion is provided on a side farther from the rod side than the penetrating portion.

7. An air-driven actuator having a cylinder, wherein the cylinder is provided with at least one air port at the end of the rod side where the piston rod guide is provided and the piston rod is pulled out, and a piston reciprocating motion space is formed inside the cylinder in which the piston reciprocates by sucking and discharging air through the air port, wherein the air-driven actuator is characterized in that: The cylinder comprises: a flange portion, which makes the end portion of the rod side protrude to the outer diameter side than the portion other than the end portion; and an enlarged diameter portion, which is provided by enlarging the inner diameter of the flange portion; The air port of the cylinder provided at the end portion on the rod side has a through hole provided so that at least a portion of the air port overlaps with the flange portion and communicates with the enlarged diameter portion.

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