Cylinder device and manufacturing method of cylinder device

Abstract

To provide a cylinder device which can maintain operation accuracy with a simple configuration even if the cylinder device is miniaturized.SOLUTION: A cylinder device 10 includes: a piston 30 having a rod 32 and a stopper 34; an air bearing 50 that supports the rod 32; a body 20 which is constituted of one article, has a through hole 28 along the axial direction of the rod 32 and a plurality of ports, and stores the piston 30 and the air bearing 50 by protruding the tip of the rod 32 from the opening on one end side of the through hole 28; and a lid 70 that closes the opening on the other end side of the through hole 28. The through hole 28 has a first hole 281 which is arranged from the one end side to the other end side, forms a closed space CP on the other end side and to which the air bearing 50 is fixed, a second hole 282 into which a part of the rod 32 is fitted, a third hole 283 into which the stopper 34 is fitted so that the stopper 34 is movable in the axial direction, and a fourth hole 284 to which the lid 70 is fixed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cylinder device and a method for manufacturing the cylinder device.

Background Art

[0002] Patent Document 1 discloses an air bearing cylinder and a cylinder system composed of the air bearing cylinder and a pressure control valve, as shown in FIG. 1, Claim 1, etc. This air bearing cylinder includes a cylinder block having a cylinder chamber and a rod insertion hole, a rod inserted into the rod insertion hole with one end protruding and having a pressure acting portion formed at a predetermined position on the non-protruding end side located in the cylinder chamber, a thrust port for supplying control air for moving the rod along its longitudinal direction into the cylinder chamber, a bearing member provided on the inner wall surface of the rod insertion hole and supporting the rod non-contactingly by ejecting pressurized air, a vacuum suction port for discharging the pressurized air ejected from the bearing member to the outside, and an exhaust passage for guiding the pressurized air from the end face on the rod protruding end side of the bearing member to the vacuum suction port. Further, the above-described cylinder system includes this air bearing cylinder and a pressure control valve, and is configured by connecting a pressure control valve for maintaining the pressure of the air in the cylinder chamber below a predetermined value to the cylinder chamber.

[0003] Referring to the abstract of Patent Document 1, it seems that the above-described cylinder system was invented for the purpose of reducing the size of the air bearing cylinder. And in order to solve the problem of the decrease in the accuracy of rod movement control, which becomes a problem with the miniaturization, this problem is solved by connecting a pressure control valve from the outside to the air bearing cylinder. Further, in the cylinder block (housing) of the above-described air bearing cylinder, as shown in FIG. 1 of Patent Document 1, a plurality of holes such as a thrust port, a rod insertion hole, a vacuum suction port, and an exhaust passage are formed. And considering the shape of these holes, it is considered that the cylinder block is not a single article but is configured by connecting a plurality of parts.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Without considering the machining difficulty, assemblability, etc., it might be possible to miniaturize the air bearing cylinder disclosed in Patent Document 1. However, in the case of Patent Document 1, in order to maintain the accuracy of the rod movement control, a pressure control valve is required as an external device connected to the air bearing cylinder. That is, in the case of Patent Document 1, it is not possible to achieve miniaturization while maintaining the operating accuracy with only the air bearing cylinder. Moreover, since the cylinder block constituting the air bearing cylinder of Patent Document 1 is composed of connecting a plurality of parts, assembly variations may occur during mass production. Along with this, variations in the operating accuracy of the air bearing cylinder after mass production may occur.

[0006] One of the objects of the present invention is to provide a cylinder device that can maintain the operating accuracy with a simple configuration even when miniaturized.

Means for Solving the Problems

[0007] The cylinder device of the first structure includes a piston having a rod and a stopper fixed to the base end thereof, an air bearing that supports while passing through the rod, a housing composed of one article, having (A) a through hole along the axial direction of the rod and (B) a plurality of ports, and accommodating the piston and the air bearing inside by protruding the tip of the rod from the opening on one end side of the through hole, a lid that closes the opening on the other end side of the through hole, and is provided with (A) The through hole includes, arranged from the opening on the one end side to the opening on the other end side, (A1) a first hole that forms a closed space on the other end side and in which the air bearing is fixed, (A2) a second hole that is smaller in diameter and deeper than the first hole and into which a part of the rod is fitted so that the rod can move in the axial direction, (A3) a third hole that is deeper than the second hole and into which the stopper is fitted so that the stopper can move in the axial direction, and (A4) a fourth hole to which the lid is fixed. (B) The plurality of ports includes, (B1) an air supply port that opens between the facing surface of the air bearing in the first hole and the outer surface of the housing, (B2) an air supply / discharge port that opens between the third hole and the outer surface, and (B3) an exhaust port that opens between the surface forming the closed space in the first hole and the outer surface.

[0008] The cylinder device of the second structure is In the cylinder device of the first structure, The air bearing is fixed to the first hole such that the position of the end face on the one end side in the axial direction is the same as the position of the end face on the one end side of the housing.

[0009] The cylinder device of the third structure is In the cylinder device of the first structure or the second structure, A spacer that is accommodated in the closed space and positions the fixing position of the air bearing in the axial direction is further provided.

[0010] The cylinder device of the fourth structure is In the cylinder device of the third structure, The spacer is a ring-shaped member into which the rod is fitted at the center, and a groove is formed on its inner peripheral surface.

[0011] The cylinder device of the fifth structure is In any one of the cylinder devices of the first structure to the fourth structure, A damper that is housed inside the third hole and absorbs vibrations generated when the stopper reaches the stop position on the one end side in the third hole during the movement of the piston. further includes The damper is attached to the surface on the one end side of the stopper.

[0012] The cylinder device of the sixth structure is In any one of the cylinder devices of the first structure to the fifth structure, A female thread is formed on the peripheral surface of the fourth hole. A male thread that fits into the female thread is formed on the outer peripheral surface of the lid. The lid is fixed to the fourth hole with the male thread tightened to the female thread.

[0013] The cylinder device of the seventh structure is In any one of the cylinder devices of the first structure to the sixth structure, A recess is formed in one or both of the surface on the other end side of the stopper and the surface on the one end side of the lid. In one or both of the stopper and the lid, a communication passage is formed for flowing air sent from the air supply / exhaust port into the recess.

[0014] The manufacturing method of the cylinder device of the first method is In the manufacturing method of the cylinder device of the third structure, A first step of using a rectangular parallelepiped-shaped metal body as the housing, (a) A step of forming a reference hole that penetrates the metal body with the same diameter as the second hole from the first surface of the rectangular parallelepiped-shaped metal body to make the metal body into a first metal body. (b) A step of forming a hole that is coaxial with the reference hole and has the same diameter and depth as the first hole from the first surface of the first metal body to make the first metal body into a second metal body having the first hole. (c) Forming a hole from the second surface of the second metal body, which is opposite to the first surface, coaxially with the reference hole, having the same diameter as the third hole, and a depth equal to the sum of the depth of the third hole and the depth of the fourth hole, to make the second metal body into a third metal body having the second hole and the third hole, and (d) Forming a hole from the second surface of the third metal body, coaxially with the reference hole, having the same diameter and the same depth as the fourth hole, to make the third metal body into a fourth metal body having the fourth hole, including a first step; a second step of inserting the spacer into the first hole of the fourth metal body and then inserting the air bearing; a third step of inserting the piston from the fourth hole of the fourth metal body after the second step; a fourth step of fixing the lid to the fourth hole after the third step; including.

[0015] A method for manufacturing a cylinder device of a second method In the method for manufacturing a cylinder device of the first method, a step that is performed before the third step and attaches a damper to the surface on the one end side of the stopper; further including.

[0016] A method for manufacturing a cylinder device of a third method In the method for manufacturing a cylinder device of the sixth structure, a first step of using a rectangular parallelepiped-shaped metal body as the housing, (a) Forming a reference hole that penetrates the metal body with the same diameter as the second hole from the first surface of the rectangular parallelepiped-shaped metal body to make the metal body into a first metal body; (b) Forming a hole coaxially with the reference hole, having the same diameter and the same depth as the first hole, from the first surface of the first metal body to make the first metal body into a second metal body having the first hole, (c) Forming a hole that is coaxial with the reference hole, has the same diameter as the third hole, and has a depth equal to the sum of the depth of the third hole and the depth of the fourth hole from the second surface of the second metal body opposite to the first surface, thereby forming the second metal body into a third metal body having the second hole and the third hole. (d) Forming a hole that is coaxial with the reference hole, has the same diameter and the same depth as the fourth hole from the second surface of the third metal body, thereby forming the third metal body into a fourth metal body having the fourth hole, and (e) Forming a female thread on the peripheral surface of the fourth hole. A first step including A second step of inserting the spacer into the first hole of the fourth metal body and then inserting the air bearing; A third step of inserting the piston into the fourth hole of the fourth metal body after the second step; A fourth step of tightening the male thread to the female thread to fix the lid to the fourth hole after the third step. is included.

Advantages of the Invention

[0017] The cylinder device of the first structure can maintain the operation accuracy with a simple configuration even when miniaturized.

[0018] The cylinder device of the second structure can discharge the air inside the housing by utilizing the opening on one end side of the through hole of the housing.

[0019] The cylinder device of the third structure can easily position the air bearing in the axial direction of the housing during assembly.

[0020] The cylinder device of the fourth structure can make it difficult for the air flowing out from the air supply port into the first hole to flow into the third hole. Along with this, since the pressure inside the third hole is easily controlled by the air flowing out from the air supply and exhaust port, the operation accuracy can be improved.

[0021] The cylinder device with the fifth structure is excellent in assemblability as compared with the structure in which the damper is attached to the boundary surface with the second hole in the third hole. In particular, this effect becomes more remarkable as the cylinder device is miniaturized because the third hole also has a smaller diameter as the cylinder device is miniaturized.

[0022] The cylinder device with the sixth structure can seal the third hole with torque applied to the entire circumferential surface of the lid. Along with this, the cylinder device with the sixth structure can suppress the leakage of the air inside the third hole from the fourth hole in the long term.

[0023] The cylinder device with the seventh structure can improve the reactivity when the piston moves as compared with the structure in which the opposing surfaces of both the stopper and the lid are in contact with each other over the entire surface.

[0024] The manufacturing method of the cylinder device of the first method is excellent in the productivity of the cylinder device because a hole is drilled in the first metal body in the first step to manufacture the housing of an article. In particular, this effect becomes more remarkable as the cylinder device is miniaturized because the housing is also miniaturized as the cylinder device is miniaturized.

[0025] The manufacturing method of the cylinder device of the second method is excellent in the productivity of the cylinder device as compared with the method in which the third step is performed after attaching the damper to the boundary surface with the second hole in the third hole. In particular, this effect becomes more remarkable as the cylinder device is miniaturized because the housing is also miniaturized as the cylinder device is miniaturized.

[0026] The manufacturing method of the cylinder device of the third method can reduce the number of parts by giving the lid and the fourth hole the function of a screw. Also, as the cylinder device is miniaturized, the lid and the means (for example, a screw) for fixing the lid are also miniaturized. Therefore, the manufacturing method of the cylinder device of the third method is more excellent in productivity as the cylinder device is miniaturized.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0028] ≪This Embodiment≫ Hereinafter, the configuration, function, operation, manufacturing method, and effects of the cylinder device 10 (see FIGS. 1 to 3, etc.) according to this embodiment will be described in the order of these descriptions with reference to the drawings.

[0029] <Configuration and Function> FIGS. 1 and 2 are perspective views of the cylinder device 10 according to this embodiment seen from different directions. FIG. 3 is a cross-sectional view of the cylinder device according to this embodiment cut along the cutting line III-III in FIG. 1.

[0030] 〔Overall Configuration〕 The cylinder device 10 includes a housing 20, a piston 30, a damper 40, an air bearing 50, a spacer 60, and a lid 70. The reference sign AX in the figure indicates the axis of the piston 30. The cylinder device 10 is arranged with the tip side of the piston 30 facing upward, and has a function of changing the pressure inside a pressure chamber CB (see FIG. 3 described later) and reciprocating the piston 30 in its axial direction (the direction of the axis AX) with respect to the housing 20. The pressure inside the pressure chamber CB rises when air is injected into the pressure chamber CB from a compressor (not shown) via the air supply and exhaust port IEP, and drops to the external pressure of the cylinder device 10 (1 atm as an example) when the air inside the pressure chamber CB is discharged to the outside via the air supply and exhaust port IEP. The cylinder device 10 shown in FIG. 3 shows the state when the pressure of the air inside the pressure chamber CB is 1 atm, that is, when the inside of the pressure chamber CB is not pressurized. In contrast, the cylinder device 10 shown in FIG. 5 described later shows the state during pressurization when the pressure of the air inside the pressure chamber CB is pressurized to a predetermined pressure. In this specification, the axial position of the piston 30 in the former (FIG. 3) state is referred to as the zero stroke position, and the axial position of the piston 30 in the latter (FIG. 5) state is referred to as the full stroke position.

[0031] Next, the cylinder device 10 will be described for each component. 〔Housing〕 FIG. 4 is a cross-sectional view of the housing 20 cut along the cutting line IV-IV from the cylinder device 10 of FIG. 1. As shown in FIGS. 1 to 4, the housing 20 is, as an example, an axially elongated cube. More specifically, as shown in FIGS. 1 and 2, both end faces in the axial direction of the housing 20 are each composed of a flat surface (one end face 22A and the other end face 22B), and the outer peripheral surface 24 (an example of the outer surface of the housing) is composed of four rectangular flat surfaces 24A and four curved surfaces 24B. The four rectangular flat surfaces 24A and the four curved surfaces 24B are arranged alternately along the circumferential direction. Here, as an example, since the width of each rectangular flat surface 24A is more than twice the width of the curved surface 24B, it can also be said that the outer peripheral surface 24 forms a square by the four rectangular flat surfaces 24A when viewed from the axial direction, and the joint portions of each other are chamfered by each curved surface 24B. Further, as an example, the size of the housing 20 is such that the length (the distance between the one end face 22A and the other end face 22B) is about 20 mm, and the width (the distance between two non-adjacent rectangular flat surfaces 24A among the four rectangular flat surfaces 24A) is about 15 mm. That is, currently, in many cylinder devices in circulation, it can be said that this size is extremely small. Incidentally, the housing 20 is, as an example, a structural body of an article manufactured by performing cutting work on a lump of metal of an article (the metal body 20x in FIG. 7 described later). The manufacturing method of the housing 20 will be described later.

[0032] As shown in FIGS. 1 to 4, the housing 20 has a plurality of holes. Here, the plurality of holes are eight blind holes 26, through holes 28, and the intake / exhaust port IEP, intake port IP, and two exhaust ports EP that constitute a plurality of ports.

[0033] First, the eight blind holes 26 will be described. Of the eight blind holes 26, four blind holes 26 open at one end face 22A of the housing 20 as shown in FIG. 1. These four blind holes 26 are each formed at a position at the same distance from the axis AX and at a position adjacent to each curved surface 24B and shifted from each other by 90° around the axis. Also, the remaining four blind holes 26 open at the other end face 22B of the housing 20 as shown in FIG. 2. These remaining four blind holes 26 are also each formed at a position at the same distance from the axis AX and at a position adjacent to each curved surface 24B and shifted from each other by 90° around the axis. Female threads are formed in each blind hole 26, and they are used as mounting holes during use according to the usage mode by the user. Note that since the eight blind holes 26 are used as mounting holes, they are not essential components in the present invention.

[0034] Next, the through hole 28 will be described with reference to FIGS. 3 and 4. The through hole 28 penetrates from one end face 22A to the other end face 22B of the housing 20. That is, the through hole 28 has openings at one end face 22A and the other end face 22B of the housing 20, respectively. The through hole 28 is axisymmetric with respect to the axis AX and is a hole having a circular cross section. Also, as will be described later, the through hole 28 is composed of a plurality of holes having different diameters depending on its axial position. Specifically, the through hole 28 is composed of a first hole 281, a second hole 282, a third hole 283, and a fourth hole 284 arranged in series from the opening on one end side to the opening on the other end side.

[0035] The first hole 281 is a hole having a diameter of D1 and a depth of L1. The diameter D1 and the depth L1 are each about 1 / 2 of the width and the length of the housing 20 as an example. Inside the first hole 281, as shown in FIG. 3, a part of a rod 32 of a piston 30, an air bearing 50, and a spacer 60, which will be described later, are arranged. The second hole 282 is a hole having a diameter D2 and a depth L2. The diameter D2 is smaller than the diameter D1 of the first hole 281. The diameter D2 is, for example, about 1 / 2 of the diameter D1 of the first hole 281. Also, the depth L2 is, for example, about 1 / 6 of the depth L1 of the first hole 281. Inside the second hole 282, as shown in FIG. 3, a part of the rod 32 of the piston 30 described later is disposed. The diameter D2 of the second hole 282 is slightly larger (by, for example, 1% to 3%) than the diameter DR of the rod 32. The third hole 283 is a hole having a diameter D3 and a depth L3. The diameter D3 is smaller than the diameter D1 of the first hole 281 and larger than the diameter D2 of the second hole 282. The diameter D3 is, for example, about 4 / 5 of the diameter D1 of the first hole 281. Also, the depth L3 is, for example, about 2 / 3 of the depth L1 of the first hole 281. The inside of the third hole 283 in the housing 20 constitutes a pressure chamber CB. And, inside the third hole 283, that is, in the pressure chamber CB, as shown in FIG. 3, a part of the piston 30 (specifically, a part of the rod 32 and the stopper 34) and a damper 40 described later are disposed. Here, the circumferential surfaces of the first hole 281, the second hole 282, and the third hole 283 each constitute a curved surface having its respective diameter regardless of the axial position. The fourth hole 284 is a hole having a diameter D4 and a depth L4. A female thread is formed on the circumferential surface of the fourth hole 284 from one end to the other end in the axial direction. The diameter D4 is larger than the diameter D1 of the first hole 281 and the diameter D3 of the third hole 283. Also, the depth L4 is, for example, about 1 / 4 of the depth L1 of the first hole 281.

[0036] Next, a plurality of ports (intake / exhaust port IEP, intake port IP, and two exhaust ports EP) will be described with reference to FIGS. 3 and 4. The intake / exhaust port IEP is a through hole that opens with one of the four rectangular planes 24A constituting the outer peripheral surface 24 of the housing 20 and the third hole 283. The intake port IP is, for example, a through hole that opens with the rectangular plane 24A where the intake / exhaust port IEP opens and the first hole 281. The diameter of the intake port IP is, for example, equivalent to the diameter of the intake / exhaust port IEP. Each of the two exhaust ports EP is, for example, a through hole that opens with a surface adjacent to one or the other side in the circumferential direction of the surface where the intake / exhaust port IEP and the intake port IP open among the four rectangular planes 24A that constitute the outer peripheral surface 24 of the housing 20, and the first hole 281. Each of the two exhaust ports EP has the same diameter and is smaller in diameter than the intake / exhaust port IEP. Further, as shown in FIG. 4, each of the two exhaust ports EP is formed in a portion of the housing 20 that is symmetric with respect to the axis AX and in a portion on the other end side of the housing 20 in the axial direction than the intake port IP. Any of the ports (intake / exhaust port IEP, intake port IP, and two exhaust ports EP) is, for example, a through hole along a direction orthogonal to the axis AX.

[0037] 〔Piston and Damper〕 Next, the piston 30 and the damper 40 will be described with reference to FIGS. 1, 3, and 5. FIG. 5 is a cross-sectional view corresponding to the cross-sectional view of FIG. 3 and is a cross-sectional view of the cylinder device 10 when the piston 30 is in the full stroke position. One end side (tip side) portion of the piston 30 is housed inside the housing 20 with a part protruding from the through hole 28 of the housing 20, and has a function of reciprocating in the axial direction along with the change in the pressure inside the pressure chamber CB. The piston 30 has a rod 32 and a stopper 34.

[0038] As shown in FIGS. 3 and 5, the rod 32 is cylindrical, and blind holes 321 and 322 each having a female thread are formed on both end faces thereof. Among the two blind holes 321 and 322, the blind hole 321 formed on the tip end face of the rod 32 is used as an attachment hole during use according to the usage mode by the user. On the other hand, the blind hole 322 formed on the base end face of the rod 32 is an attachment hole for fixing the stopper 34 to the rod 32.

[0039] As shown in FIGS. 3 and 5, the stopper 34 is disposed inside the pressure chamber CB. The stopper 34 has a disk 341 and a male screw 342. The stopper 34 is fixed to the proximal end of the rod 32. The disk 341 has a diameter larger than the diameter D2 of the second hole 282 and smaller than the diameter D3 of the third hole 283. Two notches NT (an example of a communication path) are formed at the periphery of the disk 341 as an example. The position of the other notch NT with respect to the position of one notch NT is set, for example, at a position shifted 180° in the circumferential direction with respect to the position of one notch NT. A male screw 342 extending to one end side is provided at the center and the upper surface (the surface facing one end side) of the disk 341. The stopper 34 is fixed to the rod 32 by tightening the male screw 342 into the blind hole 322 (female screw) on the proximal end side of the rod 32.

[0040] When the piston 30 moves from the zero-stroke position to the full-stroke position (when the piston 30 moves from the position in FIG. 3 to the position in FIG. 5) as the pressure in the pressure chamber CB fluctuates, the damper 40 has a function of absorbing vibrations generated when the stopper 34 reaches the stop position (upper limit) on one end side in the third hole 283. The damper 40 is, for example, an elastically deformable sheet material having a ring shape when viewed from its thickness direction. As shown in FIGS. 3 and 5, the damper 40 has the rod 32 fitted therein at the center and is attached to the upper surface of the stopper 34. Therefore, the damper 40 is configured to move together with the piston 30.

[0041] 〔Air bearing〕 Next, the air bearing 50 will be described with reference to FIGS. 1, 3, and 5. The air bearing 50 is a cylindrical sliding bearing that penetrates the rod 32 therein and supports the rod 32 that reciprocates in the axial direction.

[0042] The air bearing 50 is, for example, composed of a porous body. As described above, since the air bearing 50 reciprocates in the axial direction while passing through the rod 32 inside thereof, the diameter of the inner peripheral surface 50C is slightly larger than the diameter DR of the rod 32. Further, chamfering is performed on both end portions of the inner peripheral surface 50C. The air bearing 50 is fitted into the first hole 281 and fixed to the housing 20. Therefore, the diameter of the outer peripheral surface 50D thereof is set to a diameter that can be fitted inside the first hole 281. As an example, the method of fixing the air bearing 50 to the first hole 281 is fitting, adhesion, or the like. As an example, the fixing position of the air bearing 50 to the first hole 281 is set such that one end surface 50A thereof is at the same position as one end surface 22A of the housing 20 in the axial direction. Here, the length of the air bearing 50 (the distance between one end surface 50A and the other end surface 50B) is shorter than the depth L1 of the first hole 281. Therefore, the air bearing 50 is arranged inside the first hole 281 together with the rod 32, thereby forming a closed space CP inside the first hole 281 and on the other end side. A spacer 60 described later is arranged in the closed space CP.

[0043] Further, as shown in FIGS. 3 and 5, chamfering is performed on both end portions in the length direction (axial direction) of the outer peripheral surface 50D of the air bearing 50, and a circumferential groove 52 extending over the entire circumference in the circumferential direction is formed in the central portion. The width of the circumferential groove 52 is about the same as the diameter of the air supply port IP, and the formation range of the circumferential groove 52 in the axial direction corresponds to the formation position of the air supply port IP in the axial direction.

[0044] With the above configuration, after the air flowing into the first hole 281 from the outside through the air supply port IP enters the inside of the air bearing 50 made of a porous body from the circumferential groove 52, moves inside, and is discharged from the inner peripheral surface 50C, the air bearing 50 constitutes a sliding bearing by utilizing the air pressure between the inner peripheral surface 50C and the rod 32 (gap). Therefore, air discharged from the inner peripheral surface 50C flows out from the inner peripheral edges at both ends of the air bearing 50.

[0045] 〔Spacer〕 Next, the spacer 60 will be described with reference to FIGS. 3 and 5. The spacer 60 has the functions of (1) positioning the fixed position of the air bearing 50 in the axial direction and (2) making it difficult for the air flowing out from the inner peripheral edge on the other end side of the air bearing 50 to flow from the inside of the first hole 281 into the pressure chamber CB.

[0046] The spacer 60 is a ring-shaped member, and the rod 32 is fitted into the center thereof with a gap. Further, a circumferential groove 62 is formed on the inner peripheral surface 60C of the spacer 60. The volume of the circumferential groove 62 is larger than the total volume of the gaps between the air bearing 50 and the rod 32. The spacer 60 is arranged in contact with the other end (the boundary surface with the second hole 282) of the first hole 281 at its other end surface 60B, and by contacting the other end surface 50B of the air bearing 50 at one end surface 60A, it positions the fixed position of the air bearing 50 in the axial direction. Since the spacer 60 reciprocates in the axial direction while passing through the rod 32 inside it, the diameter of its inner peripheral surface 60C is slightly larger than the diameter DR of the rod 32. Further, chamfering is performed on both end portions of the inner peripheral surface 60C and the outer peripheral surface 60D. The spacer 60 is fitted into the first hole 281 and fixed to the housing 20. Therefore, the diameter of its outer peripheral surface 60D is set to a diameter that can be fitted into the inside of the first hole 281, similar to the case of the air bearing 50. As described above, one end surface 50A of the air bearing 50 is set to be in the same position as one end surface 22A of the housing 20, which is because the sum of the length of the air bearing 50 and the length of the spacer 60 is set to be the depth L1 of the first hole 281.

[0047] Also, as described above, a circumferential groove 62 extending over the entire circumference in the circumferential direction is formed in the central portion of the inner peripheral surface 60C of the spacer 60. The width of the circumferential groove 62 is larger than the diameter of each exhaust port EP, and the formation range of the circumferential groove 62 in the axial direction overlaps with the formation position of the exhaust port EP in the axial direction. Regarding the function of the spacer 60 in (2) above, which makes it difficult for the air flowing out from the inner peripheral edge on the other end side of the air bearing 50 to flow from the inside of the first hole 281 into the pressure chamber CB, it will be described later.

[0048] [Cover] Next, the cover 70 will be described with reference to FIGS. 2, 3, and 5. The cover 70 has a function of closing the opening on the other end side of the through hole 28.

[0049] The cover 70 is a disc-shaped member. A male thread that is fitted into and tightened against the female thread on the circumferential surface of the fourth hole 284 is formed on the circumferential surface 70C of the cover 70. A circular recess 72 that is symmetric with respect to the axis AX is formed at the center of one end surface 70A of the cover 70. The diameter of the recess 72 is set to be smaller than the diameter of the stopper 34. Therefore, as shown in FIG. 3, the cover 70 contacts the other end surface of the stopper 34 with its one end surface 70A and supports the piston 30 at the zero-stroke position.

[0050] The recess 72 overlaps with the two notches NT formed in the stopper 34 of the piston 30 in the axial direction. Therefore, the recess 72 communicates with the inside of the third hole 283 through the two notches NT. That is, when external air is sent from the air supply and exhaust port IEP to the pressure chamber CB, the external air flows into the recess 72 via the two notches NT.

[0051] The thickness of the cover 70 is set to be equal to the depth L4 of the fourth hole 284. Therefore, the other end surface 70B of the cover 70 forms the same plane as the other end surface 22B of the housing 20. Also, as described above, the cover 70 is screwed and fixed to the fourth hole 284. With the above configuration, the cover 70 is not simply closing the opening on the other end side of the through hole 28, but is fixed in a state where torque is applied to the housing 20 while pressing one end surface 70A against the interface between the fourth hole 284 and the third hole 283. On the other end face 70B of the lid 70, two blind holes 74 are formed. The position of one blind hole 74 relative to the position of the other blind hole 74 is set, as an example, to a position shifted by 180° in the circumferential direction relative to the position of one blind hole 74. The two blind holes 74 are used for inserting the pins of a driver (not shown) having a pair of pins to rotate the lid 70 around the axis when the lid 70 is screwed into the fourth hole 284.

[0052] The above is the description of the configuration and function of the cylinder device 10 of the present embodiment.

[0053] <Operation> Next, the operation of the cylinder device 10 of the present embodiment will be described with reference to FIGS. 3 and 5.

[0054] As a premise, the cylinder device 10 is arranged and used in a posture in which the tip side of the piston 30 faces upward (in FIGS. 3 and 5, a posture in which one end side faces upward). An external device including an atmosphere release valve (not shown) and a compressor (not shown) is connected to the air supply and exhaust port IEP, and another compressor (not shown) is connected to the air supply port IP. The switching operation of the atmosphere release valve and the discharge operation of compressed air by each compressor are controlled by a control device (not shown).

[0055] First, the control device operates each compressor to intermittently discharge compressed air from each compressor. As a result, the compressed air that has flowed into the inside of the first hole 281 through the air supply port IP hits the circumferential groove 52 of the air bearing 50. Then, a part of the compressed air enters the inside of the air bearing 50 from the circumferential groove 52, moves inside, and is discharged from the inner circumferential surface 50C. By continuing this state, the air bearing 50 constitutes a sliding bearing for the rod 32. On the other hand, the compressed air that has flowed into the interior of the third hole 283, that is, the pressure chamber CB, through the air supply and exhaust port IEP, passes through the two notches NT formed in the stopper 34 and flows into the space formed by the stopper 34 and the recess 72 of the lid 70. Then, the piston 30 receives a thrust from the lower side (the other end side) and moves upward (one end side). When the damper 40 attached to the upper surface of the stopper 34 contacts the interface with the second hole 282 in the third hole 283, the piston 30 stops (see Fig. 5). Next, the control device stops the discharge of the compressed air from the compressor connected to the air supply and exhaust port IEP and opens the atmosphere release valve. As a result, the compressed air inside the pressure chamber CB is discharged to the outside through the atmosphere release valve via the air supply and exhaust port IEP. Then, as the air pressure inside the pressure chamber CB decreases, the thrust also decreases, and the piston 30 at the full stroke position moves to the zero stroke position (falls by its own weight). As described above, the control device reciprocates the piston 30 within a defined range by controlling an external device and another compressor.

[0056] The above is the description of the operation of the cylinder device 10 of the present embodiment.

[0057] <Manufacturing Method> Next, the manufacturing method of the cylinder device 10 of the present embodiment will be described with reference to Figs. 6, 7, and 8. Fig. 6 is a flowchart of the manufacturing method of the cylinder device 10. Fig. 7 is a schematic diagram for explaining the details of the first step in the manufacturing method of the cylinder device 10, and Fig. 8 is a schematic diagram for explaining the details of the second to fourth steps. The manufacturing method of the cylinder device 10 includes a first step, a second step, a third step, and a fourth step, and each step is performed in the order of these descriptions. Hereinafter, the manufacturing method of the cylinder device 10 will be described step by step.

[0058] 〔First Step〕 The first step is a step of processing a rectangular parallelepiped-shaped metal body 20x (see Fig. 7) into a housing 20. The first step further includes steps a, b, c, d, e, and f, and is performed through the steps in the described order. The first step is performed using, for example, a cutting machine (not shown). Note that the outer peripheral surface of the rectangular parallelepiped-shaped metal body 20x is processed into a shape equivalent to the outer peripheral surface 24 of the housing 20 as a premise.

[0059] (Step a) Step a is a step of forming a through hole TH1 (an example of a reference hole) in the first surface P1 of the metal body 20x to obtain a first metal body 20a. In this case, the four curved surfaces 24B of the metal body 20x are applied to the four-jaw chuck of the cutting machine for chucking, and while rotating the metal body 20x around the axis, drilling is performed using a drill. Here, the diameter of the through hole TH1 is set to the diameter of the second hole 282.

[0060] (Step b) Step b is a step of forming a hole having the same axis as the through hole TH1, the same diameter as the first hole 281, and the same depth from the first surface P1 of the first metal body 20a, and converting the first metal body 20a into a second metal body 20b having the first hole 281. In this case, with the same machining setting as in step a, the drill is replaced with a boring tool to perform internal diameter machining to form the first hole 281.

[0061] (Step c) Step c is a step of forming a hole TH2 having the same axis as the through hole TH1, the same diameter as the third hole 283, and a depth L3 + L4 obtained by adding the depth L3 of the third hole 283 and the depth L4 of the fourth hole 284 from the second surface P2 on the side opposite to the first surface P1 of the second metal body 20b, and converting the second metal body 20b into a third metal body 20c having the second hole 282 and the third hole 283. In this case, the four-jaw chuck of the cutting machine is reversed, and while rotating the second metal body 20b around the axis, internal diameter machining is performed using a boring tool to form the hole TH2.

[0062] (Step d) Step d is a step of forming a hole coaxial with TH1, having the same diameter and the same depth as the fourth hole 284, from the second surface P2 of the third metal body 20c, to make the third metal body 20c into a fourth metal body 20d having the fourth hole 284. In this case, with the same machining setting as in step c, inner diameter machining is performed using a tool bit to form a fourth hole TH3 in which a female thread is not formed.

[0063] (Step e) Step e is a step of forming a female thread on the circumferential surface of the fourth hole TH3 in which a female thread is not formed, to make the fourth metal body 20d into a fifth metal body 20e. In this case, with the same machining setting as in steps c and d, inner diameter machining is performed using a threading tool bit to form a female thread in the fourth hole TH3 in which a female thread is not formed to form the fourth hole 284.

[0064] (Step f) Step f is a step of forming four ports (intake and exhaust port IEP, intake port IP, and two exhaust ports EP) on the circumferential surface of the fifth metal body 20e. When step f is completed, the housing 20 is manufactured.

[0065] 〔Second step〕 The second step is a step of inserting the spacer 60 into the first hole 281 of the housing 20, and then inserting the air bearing 50.

[0066] 〔Third step〕 The third step is a step of attaching the damper 40 to one end surface of the stopper 34, and then inserting the piston 30 with the damper 40 from the fourth hole 284 of the housing 20.

[0067] 〔Fourth step〕 The fourth step is a step of fixing the lid 70 to the fourth hole 284. Specifically, the lid 70 is fixed to the fourth hole 284 by tightening the male thread on the outer circumferential surface of the lid 70 to the female thread of the fourth hole 284. And when the fourth step is completed, the cylinder device 10 is completed.

[0068] The above is the description of the manufacturing method of the cylinder device 10 of the present embodiment.

[0069] <Effect> Next, the effects of the present embodiment will be described. Hereinafter, the effects achieved for each feature of the present embodiment will be described. However, when comparing with a comparative form assumed for convenience of the present embodiment, it should be noted that the same names and reference numerals are used for the components that are the same as those of the present embodiment in the comparative form.

[0070] 〔First effect〕 The first effect is an effect achieved by the relationship between the structure of the housing 20 of the cylinder device 10 and the components other than the housing 20.

[0071] The first effect will be described by comparing the cylinder device 10 of the present embodiment with the cylinder device (not shown) of the first comparative form described later. The cylinder device of the first comparative form differs from the cylinder device 10 of the present embodiment only in the following three points. The first point is that the air bearing 50 is inserted to the other end of the first hole 281 and there is no closed space CP. The second point is that the opening on one end side of the first hole 281 is sealed by a lid (not shown) or a part of the housing. The third point is that the exhaust port EP is formed in a portion on the one end side in the axial direction of the housing 20 rather than the air bearing 50.

[0072] When the cylinder device of the first comparative form is operated, among the compressed air discharged from the inner peripheral surface 50C of the air bearing 50 and flowing out from the inner peripheral edges at both ends of the air bearing 50, the compressed air flowing out from the inner peripheral edge at the other end may flow into the pressure chamber CB through the gap between the second hole 282 and the rod 32. On the other hand, inside the pressure chamber CB, the piston 30 receiving thrust from the compressed air flowing in through the air supply and exhaust port IEP moves (rises) from the zero stroke position (see FIG. 3) to the full stroke position (see FIG. 5). During this movement operation, when the compressed air discharged from the air bearing 50 flows into the inside of the pressure chamber CB, the pressure inside the pressure chamber CB cannot be controlled only by the compressed air flowing in through the air supply and exhaust port IEP, that is, the compressed air discharged from the compressor controlled by the control device.

[0073] In contrast, as shown in FIG. 4, the housing 20 of the present embodiment has (1) a first hole 281, a second hole 282, a third hole 283, and a fourth hole 284 arranged from one end side in the axial direction to the other end side and each along the axis AX, and (2) an intake and exhaust port IEP, an intake port IP, and two exhaust ports EP that are linear while intersecting the axis AX respectively. The intake port IP opens at one end side of the first hole 281, and the exhaust port EP opens at the other end side of the first hole 281. An air bearing 50 is disposed in the first hole 281 with its other end side open. As described above, the configuration of the housing 20 of the present embodiment can be said to be a simple configuration compared to the case of the first comparative form.

[0074] When the cylinder device 10 of the present embodiment is operated, among the compressed air flowing out from the inner peripheral edges at both ends of the air bearing 50, the compressed air flowing out from the inner peripheral edge at the other end always flows into the closed space CP (see FIGS. 3 and 5). That is, unlike the case of the first comparative form, it does not flow into the gap between the second hole 282 and the rod 32 immediately after flowing out from the inner peripheral edge at the other end. Further, the closed space CP communicates with the outside of the housing 20 through the two exhaust ports EP. Therefore, at least a part of the compressed air flowing out from the inner peripheral edge at the other end of the air bearing 50 is discharged to the outside of the housing 20 via the closed space CP and the two exhaust ports EP. Also, as the piston 30 moves (rises) from the zero-stroke position (see FIG. 3) to the full-stroke position (see FIG. 5), the compressed air pushed out from the pressure chamber CB always flows through the gap between the second hole 282 and the rod 32 and into the closed space CP. The compressed air from the pressure chamber CB is also discharged to the outside of the housing 20 via the closed space CP and the two exhaust ports EP. Therefore, the pressure inside the pressure chamber CB is stabilized when the piston 30 moves (rises). As described above, in the case of the present embodiment, compared to the case of the first comparative form, the compressed air flowing into the first hole 281 in which the air bearing 50 is disposed is less likely to flow into the second hole 282. That is, in the case of the present embodiment, compared to the case of the first comparative form, the control device can move the piston 30 with higher precision.

[0075] Therefore, the cylinder device 10 of the present embodiment can perform the moving operation of the piston 30 with high precision as compared with the cylinder device of the first comparative form. In particular, when miniaturized as in the cylinder device 10 of the present embodiment, the influence of the problems that may occur in the case of the first comparative form becomes prominent. From this point, it can be said that the cylinder device 10 of the present embodiment is effective in that it can maintain the operation accuracy with a simple configuration even when miniaturized.

[0076] 〔Second effect〕 The second effect is the effect that the air bearing 50 is fixed to the first hole 281 such that the position of one end surface 50A thereof in the axial direction is the same as the position of one end surface 22A of the housing 20 (see FIGS. 1, 3, etc.). The second effect will be described by comparing the cylinder device 10 of the present embodiment with a cylinder device (not shown) of a second comparative form described later. The cylinder device of the second comparative form is different from the cylinder device 10 of the present embodiment only in that the opening on one end side of the first hole 281 is sealed by a lid (not shown) or a part of the housing. And in the case of the cylinder device of the second comparative form, the compressed air flowing out from the inner peripheral edge at one end among the compressed air flowing out from the inner peripheral edges at both ends of the air bearing 50 cannot be directly discharged to the outside.

[0077] On the other hand, in the case of the present embodiment, as shown in FIGS. 3 and 5, the air bearing 50 is fixed to the first hole 281 such that the position of one end surface 50A thereof in the axial direction is the same as the position of one end surface 22A of the housing 20. Therefore, in the case of the present embodiment, while allowing the compressed air flowing out from the inner peripheral edge at the other end among the compressed air flowing out from the inner peripheral edges at both ends of the air bearing 50 to flow into the closed space CP, the compressed air flowing out from the entire circumference of the inner peripheral edge at the other end is directly discharged to the outside. As a result, the cylinder device 10 of the present embodiment can reduce the amount of compressed air flowing into the closed space CP as compared with the cylinder device of the second comparative form. Further, the cylinder device 10 of the present embodiment can discharge the compressed air inside the housing 20 by using the opening on one end side of the through hole 28 provided in the housing 20.

[0078] Therefore, the cylinder device 10 of the present embodiment can perform the moving operation of the piston 30 with high precision compared to the cylinder device of the second comparative form. In particular, when miniaturized like the cylinder device 10 of the present embodiment, the influence of the problems that can occur in the case of the second comparative form becomes prominent. From this point, it can be said that the cylinder device 10 of the present embodiment is effective in that it can maintain the operation accuracy with a simple configuration even when miniaturized.

[0079] 〔The third effect〕 The third effect is the effect of the cylinder device 10 of the present embodiment including the spacer 60 (see FIGS. 3 and 5). Therefore, the cylinder device 10 of the present embodiment can easily position the fixing position of the air bearing 50 in the axial direction (see the second step in FIG. 8).

[0080] 〔The fourth effect〕 The fourth effect is the effect of the spacer 60 being a ring-shaped member and a circumferential groove 62 being formed in its inner peripheral surface 60C (see FIGS. 3 and 5). The above-mentioned first effect requires that a closed space CP is formed on the other end side of the air bearing 50 in the first hole 281. Further, the above-mentioned third effect requires that the spacer 60 is arranged in the closed space CP. Then, these two requirements may seem to be mutually conflicting requirements. However, the spacer 60 of the present embodiment is a ring-shaped member in which a circumferential groove 62 is formed in the inner peripheral surface 60C. Therefore, the cylinder device 10 of the present embodiment can achieve the first effect by forming a closed space with the inner peripheral surface 60C and the rod 32. Specifically, with this configuration, (1) the compressed air flowing out from the air bearing 50 into the circumferential groove 62 is discharged to the outside of the housing 20 through the two exhaust ports EP, and (2) the compressed air flowing from the compression chamber CB through the gap between the second hole 282 and the rod 32 and flowing out into the circumferential groove 62 is also discharged to the outside of the housing 20 through the two exhaust ports EP. That is, since the circumferential groove 62 is formed on the inner peripheral surface 60C of the spacer 60, the compressed air flowing through the two flow paths (1) and (2) can be discharged to the outside, so that the compressed air flowing through each flow path can flow stably. In addition, the cylinder device 10 of the present embodiment can achieve the third effect by arranging the spacer 60 on the other end side of the first hole 281.

[0081] In addition, from another perspective, since the spacer 60 is arranged between the air bearing 50 and the pressure chamber CB in the axial direction, the spacer 60 becomes a flow path resistance for the compressed air discharged from the inner peripheral edge of the other end of the air bearing 50. Therefore, the spacer 60 makes it difficult for the compressed air flowing out from the inner peripheral edge on the other end side of the air bearing 50 to flow from the inside of the first hole 281 into the pressure chamber CB (and the second hole 282). Along with this, since the pressure inside the pressure chamber CB is easily controlled by the compressed air flowing out from the air supply and exhaust port IEP, it can be said that the operation accuracy of the piston 30 can be improved.

[0082] 〔The Fifth Effect〕 The fifth effect is the effect that the damper 40 is attached to the surface on one end side of the stopper 34 (see FIGS. 3 and 5). For example, in the case of the third comparative form in which the damper 40 is attached to the boundary surface between the second hole 282 and the third hole 283, it is necessary to attach the damper 40 to the boundary surface during assembly. However, as the housing 20 becomes smaller and the diameter of the third hole 283 becomes smaller, it becomes more difficult to hold the damper 40 with some gripping tool and fix it to the boundary surface. Therefore, the cylinder device 10 of the present embodiment is excellent in terms of ease of assembly compared to the case of the third comparative form. In particular, this effect becomes more prominent as the cylinder device is miniaturized because the diameter of the third hole also becomes smaller as the cylinder device is miniaturized.

[0083] In addition, since the damper 40 is elastically deformed under pressure during operation, it can be handled as a replacement part. From this point of view, in the case of the present embodiment, it is sufficient to remove and replace the damper 40 from the piston 30, so it can be said that the damper 40 is also excellent in terms of ease of replacement compared to the case of the third comparative form.

[0084] 〔Sixth effect〕 The sixth effect is the effect that a male thread is formed on the outer peripheral surface 70C of the lid 70 and a female thread is formed on the peripheral surface of the fourth hole 284, and the lid 70 is fixed to the fourth hole 284 by tightening the male thread to the female thread (see FIGS. 3 and 5). Since the lid 70 is fixed to the housing 20 in this way, the cylinder device 10 of the present embodiment can seal the third hole 283 (can form the pressure chamber CB) with torque applied to the entire peripheral surface of the lid 70. Since the pressure chamber CB changes to a pressure state between atmospheric pressure and a pressure higher than atmospheric pressure during its operation, the lid 70 is pressurized from the upper surface side during operation. However, since the lid 70 is fixed to the fourth hole 284 with torque applied to its entire peripheral surface, it does not loosen easily. Therefore, the cylinder device 10 of the present embodiment can suppress the leakage of the air inside the third hole 283 (or the pressure chamber CB) from the fourth hole 284 in the long term. In addition, the cylinder device 10 of the present embodiment also has the effect of reducing the number of parts by giving the lid 70 itself the function of a screw.

[0085] 〔Seventh effect〕 The seventh effect is that a recess 72 is formed in one end surface 70A of the lid 70, and two notches NT for flowing the compressed air sent from the air supply and exhaust port IEP into the recess 72 are formed in the stopper 34 (see FIGS. 3 and 5). Since the cylinder device 10 of the present embodiment has the above characteristics, when compressed air is sent from the air supply and exhaust port IEP into the pressure chamber CB, the compressed air flows into the space formed by the stopper 34 and the recess 72 via the two notches NT. As a result, the piston 30 (see FIG. 3) disposed above the recess 72 at the zero stroke receives a thrust from the lower side and moves upward (to the one end side). For example, in the case of the fourth comparative form in which the opposing surfaces of both the stopper 34 and the lid 70 are in contact with each other over the entire surface, the above-described operation does not occur. Therefore, the cylinder device 10 of the present embodiment can improve the reactivity during the movement of the piston 30 as compared with the case of the fourth comparative form.

[0086] 〔The eighth effect〕 The eighth effect is that the manufacturing method of the cylinder device 10 of the present embodiment includes the above-described first step, second step, third step, and fourth step, and each step is performed in this order of description (see FIGS. 7 and 8). In the manufacturing method of the cylinder device 10 of the present embodiment, in the first step, a hole is drilled in the metal body 20x to manufacture the housing 20 of one article. In this case, it is possible to perform all the steps while the metal body 20x is first chucked in the cutting machine used for processing. Therefore, the manufacturing method of the cylinder device 10 of the present embodiment is excellent in the productivity of the cylinder device 10. In particular, this effect becomes more remarkable as the cylinder device 10 is miniaturized because the housing 20 is also miniaturized as the cylinder device 10 is miniaturized.

[0087] 〔The ninth effect〕 The ninth effect is the effect of performing a step of attaching the damper 40 to the surface on one end side of the stopper 34 before the third step or in the first half of the third step (see the third step (first half) in FIG. 8). In the case of the third comparative form described above, it is necessary to attach the damper 40 to the boundary surface during assembly. However, it is not easy to hold the damper 40 with some kind of gripper and fix it to the boundary surface. On the other hand, in the case of the present embodiment, the damper 40 may be attached to the piston 30 before being inserted into the housing 20. Therefore, the manufacturing method of the cylinder device 10 of the present embodiment is excellent in terms of ease of assembly as compared with the case of the third comparative form.

[0088] 〔Tenth effect〕 The tenth effect is the effect of screwing and fixing the lid 70 to the fourth hole 284 by giving the lid 70 the function of a male screw in the method of fixing the lid 70 to the housing 20 in the fourth step (see the fourth step in FIG. 8). As the cylinder device 10 becomes smaller, the lid 70 and the means for fixing the lid 70 (for example, a screw) also become smaller. However, as the lid 70 and the screw become smaller, both are miniaturized, so it is not easy to fix the lid 70 with a screw. In addition, processing for forming a small screw hole for fixing the lid 70 in the housing 20 is also required. Therefore, the manufacturing method of the cylinder device 10 of the present embodiment can reduce the number of parts by giving the lid 70 and the fourth hole 284 the function of a screw. In addition, the manufacturing method of the cylinder device 10 of the present embodiment is excellent in productivity as it becomes smaller.

[0089] The above is the description of the effects of the present embodiment. Also, the above is the description of the present embodiment.

[0090] ≪Multiple modification examples≫ As described above, the present invention has been described with reference to the foregoing embodiment (see FIGS. 3, 7, etc.). However, the forms included in the technical scope of the present invention are not limited to the foregoing embodiment. For example, multiple modification examples described later are also included. Hereinafter, multiple modification examples of the cylinder device 10 of the present embodiment will be described. Note that in each drawing referred to in the multiple modification examples, components having the same function are denoted by the same reference numerals or similar reference numerals.

[0091] Although the cylinder device 10 has been described as having a small shape in this embodiment, its dimensions are merely examples and it may be larger. Also, although the number of notches NT formed in the stopper 34 has been described as two in this embodiment, the number of notches NT may be one or three or more. It is sufficient that the compressed air flowing into the pressure chamber CB can reach the recess 72 through the notch NT. From this perspective, the notch NT includes a through-hole. Also, in this embodiment, the recess 72 is formed in one end surface 70A of the lid 70 in order to enhance the thrust received by the piston 30, but the recess may be formed in the lower surface of the stopper 34 (the surface facing the one end surface 70A). Also, instead of the notch NT that functions as a communication passage, a communication passage may be formed in one or both of the housing 20 and the one end surface 70A of the lid 70. Further, the recess may be formed in both the one end surface 70A of the lid 70 and the lower surface of the stopper 34. Also, in this embodiment, the spacer 60, which is a member different from the housing 20, is used to position the air bearing 50, but the portion corresponding to the spacer 60 may be configured as a part of the housing 20. According to this modification, the number of parts corresponding to the spacer 60 can be reduced. Also, in this embodiment, the number of exhaust ports EP is taken as two as an example, but it may be one or three or more.

[0092] The above is the description of a plurality of modifications.

Description of Reference Numerals

[0093] 10 Cylinder device 20 Housing 20a First metal body 20b Second metal body 20c Third metal body 20d Fourth metal body 20e Fifth metal body 20x Metal body 22A One end surface 22B The other end surface 24 Outer peripheral surface 24A Rectangular Plane 24B Curved Surface 26 Four Stop Holes 28 Through-Hole 281 First Hole 282 Second Hole 283 Third Hole 284 Fourth Hole 30 Piston 32 Rod 321 Stop Hole 322 Stop Hole 34 Stopper 341 Disc 342 Male Screw 40 Damper 50 Air Bearing 50A One End Face 50B Other End Face 50C Inner Peripheral Surface 50D Outer Peripheral Surface 52 Circumferential Groove 60 Spacer 60A One End Face 60B Other End Face 60C Inner Peripheral Surface 60D Outer Peripheral Surface 62 Circumferential Groove 70 Cover 70A One End Face 70B Other End Face 70C Peripheral Surface 74 Two Stop Holes AX Axis CB Pressure Chamber CP Closed Space D1 Diameter of the First Hole D2 Diameter of the Second Hole D3 Diameter of the Third Hole D4 Diameter of the Fourth Hole DR Diameter of the Rod EP Exhaust Port IEP Supply and Exhaust Port IP Supply Port L1 Depth of the First Hole L2 Depth of the Second Hole L3 Depth of the Third Hole L4 Depth of the Fourth Hole TH1 Through-Hole A hole with a depth equal to the sum of the depths of the third hole of TH2 and the fourth hole of TH2 TH3 The fourth hole in which no female thread is formed

Claims

1. A piston having a rod and a stopper fixed to the proximal end thereof, An air bearing that supports while passing through the rod, A housing composed of one article, having (A) a through hole along the axial direction of the rod and (B) a plurality of ports, and housing the piston and the air bearing therein by protruding the tip of the rod from the opening on one end side of the through hole, A lid that closes the opening on the other end side of the through hole, Comprising: (A) The through hole includes, arranged from the opening on the one end side to the opening on the other end side, (A1) a first hole that forms a closed space on the other end side and to which the air bearing is fixed, (A2) a second hole that is smaller in diameter and shallower than the first hole and into which a part of the rod is fitted so that the rod can move in the axial direction, (A3) a third hole that is deeper than the second hole and into which the stopper is fitted so that the stopper can move in the axial direction, and (A4) a fourth hole to which the lid is fixed, (B) The plurality of ports include (B1) an air supply port that opens between the opposing surface of the air bearing in the first hole and the outer surface of the housing, (B2) an air supply / discharge port that opens between the third hole and the outer surface, and (B3) an exhaust port that opens between the surface forming the closed space in the first hole and the outer surface, A cylinder device.

2. The air bearing is fixed to the first hole such that the position of the end surface on the one end side in the axial direction is the same as the position of the end surface on the one end side of the housing. The cylinder device according to Claim 1.

3. A spacer accommodated in the closed space for positioning the fixing position of the air bearing in the axial direction, Further comprising: The cylinder device according to Claim 1 or 2.

4. The spacer is a ring-shaped member into which the rod is fitted at the center, and a groove is formed on its inner peripheral surface. The cylinder device according to Claim 3.

5. A damper accommodated inside the third hole for absorbing vibrations generated when the stopper reaches the stop position on the one end side in the third hole during movement of the piston, Further comprising: The damper is attached to the surface on the one end side of the stopper. The cylinder device according to Claim 1.

6. A female thread is formed on the peripheral surface of the fourth hole, A male thread that fits into the female thread is formed on the outer peripheral surface of the lid. The lid is fixed to the fourth hole with the male screw tightened to the female screw. The cylinder device according to claim 1.

7. A spacer housed in the closed space for positioning the fixing position of the air bearing in the axial direction. further comprising A female screw is formed on the peripheral surface of the fourth hole. A male screw that fits into the female screw is formed on the outer peripheral surface of the lid. The lid is fixed to the fourth hole with the male screw tightened to the female screw. The cylinder device according to claim 5.

8. A recess is formed in one or both of the surface on the other end side of the stopper and the surface on the one end side of the lid. In one or both of the stopper and the lid, a communication passage for flowing the air sent from the air supply and exhaust port into the recess is formed. The cylinder device according to claim 1.

9. A first step of using a rectangular parallelepiped metal body as the housing, (a) A step of forming a reference hole that penetrates the metal body with the same diameter as the second hole from the first surface of the rectangular parallelepiped metal body to make the metal body into a first metal body. (b) A step of forming a hole having the same axis as the reference hole, the same diameter and the same depth as the first hole from the first surface of the first metal body to make the first metal body into a second metal body having the first hole. (c) A hole having the same axis as the reference hole, the same diameter as the third hole, and a depth equal to the sum of the depth of the third hole and the depth of the fourth hole is formed from the second surface of the second metal body opposite to the first surface, and the second metal body is made into a third metal body having the second hole and the third hole, and (d) A hole having the same axis as the reference hole, the same diameter and the same depth as the fourth hole is formed from the second surface of the third metal body to make the third metal body into a fourth metal body having the fourth hole. including a first step; A second step of inserting the spacer into the first hole of the fourth metal body and then inserting the air bearing. After the second step, a third step of inserting the piston through the fourth hole of the fourth metal body. After the third step, a fourth step of fixing the lid to the fourth hole. including The manufacturing method of the cylinder device according to claim 3.

10. A step performed before the third step, of attaching a damper to the surface on the one end side of the stopper. further comprising The manufacturing method of the cylinder device according to claim 9.

11. A first step of using a rectangular parallelepiped metal body as the housing. Step 1 including: (a) forming a reference hole that penetrates the metal body with the same diameter as the second hole from the first surface of the rectangular parallelepiped-shaped metal body to make the metal body the first metal body; (b) forming a hole that is coaxial with the reference hole, has the same diameter and the same depth as the first hole from the first surface of the first metal body to make the first metal body the second metal body having the first hole; (c) forming a hole that is coaxial with the reference hole, has the same diameter as the third hole, and has a depth equal to the sum of the depth of the third hole and the depth of the fourth hole from the second surface of the second metal body opposite to the first surface to make the second metal body the third metal body having the second hole and the third hole; (d) forming a hole that is coaxial with the reference hole, has the same diameter and the same depth as the fourth hole from the second surface of the third metal body to make the third metal body the fourth metal body having the fourth hole; and (e) forming a female thread on the peripheral surface of the fourth hole; Step 2 including inserting the spacer into the first hole of the fourth metal body and then inserting the air bearing; Step 3 including inserting the piston from the fourth hole of the fourth metal body after Step 2; Step 4 including tightening the male thread to the female thread to fix the lid to the fourth hole after Step 3; The method for manufacturing a cylinder device according to claim 7. ​ ​

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