JP5702094B2 - Air bearing type air cylinder device - Google Patents

Description

  The present invention relates to an air bearing type air cylinder device.

  In principle, an air bearing type air cylinder device is configured to eject air from an outer peripheral surface (air bearing) of a piston (air piston) fitted in a cylinder body (pipe), and A sliding resistance of zero is realized by forming an air film with a film thickness of about several μm in between.

Japanese Patent Laid-Open No. 2004-11789 JP 2007-229884 A Japanese Patent No. 3811284

  However, in the conventional air bearing type air cylinder device, it is difficult to obtain a long rod (piston) stroke by a short cylinder body. This is because it is necessary to maintain the roundness (linearity) of the pipe body (cylinder body) with high accuracy in order to maintain an air film of about several μm using a short air piston. In the current machining technology, the longer the pipe body, the more difficult it is to secure the roundness. For this reason, the conventional product requires a relatively long air piston length with respect to the cylinder body length in order to prevent the air film from being cut. Therefore, the rod stroke is shorter than the entire cylinder length. It was.

  The present invention is based on the above problem awareness, and obtains an air-bearing type air cylinder device that can make the rod stroke longer than the entire cylinder length. With the goal.

  In the present invention, if the coupling structure of the air piston and the piston rod, which has been conventionally rigid, is changed to a flexible structure, the variation (change) in the length direction of the roundness of the cylinder body (pipe body) This is based on the viewpoint that the coupling portion of the air piston and the piston rod can follow and the air film can be prevented from being cut.

The present invention comprises a cylinder body comprising a pipe body, an air piston provided with an air bearing for jetting air from an outer peripheral surface fitted to the cylinder body, and a piston rod coupled to the air piston. In the air-bearing type air cylinder device in which the entire surface facing the cylinder body is made of a porous body, a through hole formed in the shaft portion of the air piston; the air piston and a piston rod inserted through the through hole as a shaft And an elastic elastic coupling means for supporting relative movement in the direction; and a radial elastic coupling means for supporting the air piston and the piston rod inserted through the through hole so as to be relatively movable in the radial direction. It is characterized by.

  Specifically, the axial elastic coupling means is, for example, a pair of elastic rings positioned at both ends of the air piston and fitted to the piston rod, and the pair of elastic rings in contact with both end surfaces of the air piston without any gap. It can comprise from the fixing means fixed to the piston rod in the state.

  Specifically, the radial elastic coupling means can be constituted by, for example, at least a pair of elastic rings (O-rings) interposed between the through holes of the air piston and the piston rod with different axial positions. .

  The elastic ring or O-ring is practically formed from a rubber material.

  The supply of compressed air to the air bearing of the air piston can be performed by a path different from the path of the piston operating air that operates the air piston via the shaft passage formed in the piston rod. Or it can also carry out using the piston operation | movement air which operates an air piston through the air inlet port pierced at the end surface of the air piston.

  The cylinder body is practically an aluminum alloy pipe. As the air bearing of the air piston, a well-known material (structure) such as a porous body or an orifice throttle (an air bearing whose surface of the air ejection is in a surface throttle state) can be used.

  It is preferable to provide an inner diameter sliding type air bearing at the projecting portion of the piston rod from the cylinder body.

  The present invention relates to an air-bearing air comprising a cylinder body comprising a pipe body, an air piston having an air bearing that ejects air from an outer peripheral surface fitted to the cylinder body, and a piston rod coupled to the air piston. In the cylinder device, a through hole formed in a shaft portion of an air piston; an axial elastic coupling means for supporting the air piston and a piston rod inserted through the through hole so as to be relatively movable in the axial direction; and the air piston And a radial elastic coupling means for supporting the piston rod inserted through the through-hole so as to be relatively movable in the radial direction, so that the roundness variation (change) of the roundness of the cylinder body (pipe body) is provided. ), The coupling part of the air piston and piston rod follows, and the air film breaks between the outer surface of the air piston and the inner surface of the cylinder body. Less likely to occur. For this reason, an air bearing type air cylinder device can be obtained in which the rod stroke is longer than the entire cylinder length, or the entire cylinder length can be shortened with respect to the required rod stroke.

It is sectional drawing which shows one Embodiment of the air-bearing type air cylinder apparatus by this invention. FIG. 2 is an enlarged sectional view around an air piston of the air bearing type air cylinder device of FIG. 1. It is an expanded sectional view which shows the operation | movement condition of the air bearing type air cylinder apparatus of FIG. It is sectional drawing which shows another embodiment of the air-bearing type air cylinder apparatus by this invention. FIG. 5 is an enlarged sectional view around an air piston of the air bearing type air cylinder device of FIG. 4.

  1 to 3 show an embodiment in which the present invention is applied to a single-acting air-bearing air cylinder device. A perforated end plate 11 and an end block 12 are provided at both ends of a cylinder body 10 made of an aluminum alloy high-precision pipe, and a buffer member 11 a is fixed to the inner surface of the perforated end plate 11. .

  The end block 12 is formed with a through hole 12b having an outer end inner flange 12a in the shaft portion, and an inner diameter sliding air bearing 13 is inserted into the through hole 12b. Between the outer peripheral surface of the inner diameter sliding air bearing 13 and the inner peripheral surface of the through hole 12 b, a pair of O-rings 14 are located in different positions in the axial direction. A pair of elastic rings 15 are located on the surface. The pair of elastic rings 15 fills the gap between one end surface of the inner diameter sliding air bearing 13 and the retainer ring 16 and the other end surface of the inner diameter sliding air bearing 13 and the inner flange 12a of the end block 12 without gaps. In the state (for example, in a state where the pair of elastic rings 15 are compressed in the axial direction), the inner diameter sliding air bearing 13 is supported by the end block 12 via the retainer ring 16.

  An air bearing air supply path for supplying the compressed air of the compressed air source P to the outer peripheral surface of the inner diameter sliding air bearing 13 between the pair of O-rings 14 through the end block 12 via the air bearing air supply device PA. 17 and a piston operating air supply path 18 for supplying the compressed air of the compressed air source P to the inside of the cylinder body 10 via the piston operating air supply device PS.

  An air piston 20 is fitted in the cylinder body 10, and a hollow piston rod 30 coupled to the air piston 20 projects outside through the retainer ring 16 and the shaft hole 13 a of the inner diameter sliding air bearing 13. . The inner diameter of the shaft hole 13a and the outer diameter of the piston rod 30 are processed with high accuracy so as to have a minimum clearance, and the compressed air supplied from the air bearing air supply path 17 is the shaft hole 13a of the inner diameter sliding air bearing 13. The piston rod 30 is supported on the inner surface of the shaft hole 13a in a non-contact manner.

  The air piston 20 has a through hole 21 in its shaft portion, and a piston rod 30 is inserted into the through hole 21. Between the inner peripheral surface of the through hole 21 and the outer peripheral surface of the piston rod 30, a pair of O-rings (elastic rings) 22 are interposed at different positions in the axial direction. The piston rod 30 and the through hole 21 are coupled in a non-contact state and relatively movable in the radial direction. That is, the O-ring 22 constitutes a radial elastic coupling means for coupling the air piston 20 and the piston rod 30 inserted through the through hole 21 so as to be relatively movable in the radial direction.

  A pair of elastic rings 23 fitted to the piston rod 30 are positioned at both ends of the air piston 20, and the pair of elastic rings 23 are buried in both ends of the air piston 20 without gaps in the piston rod 30. An end plate 24 and a retainer ring 25 as fixing means that are brought into contact in a state (for example, in a state where the pair of elastic rings 23 are compressed in the axial direction) are fixed. With the elastic force of the pair of elastic rings 23, the air piston 20 is coupled to the piston rod 30 so as to be capable of relative movement in the axial direction. That is, the pair of elastic rings 23 and the end plate 24 and the retainer ring 25 as fixing means are axially elastically coupled to the air piston 20 and the piston rod 30 inserted through the through hole 21 so as to be relatively movable in the axial direction. It constitutes a coupling means.

  An outer diameter sliding air bearing 26 is provided on the outer peripheral surface of the air piston 20. As the outer diameter sliding air bearing 26 (and the inner diameter sliding air bearing 13), a porous type using sintered metal or carbon, or an orifice throttle type in which the air ejection surface is in a surface throttle state is known. In the present invention, any type can be used. The outer diameter sliding air bearing 26 includes a compressed air source P, an air bearing air supply device PA, a shaft passage (air bearing air supply passage) 31 of the piston rod 30, and a radial passage (air bearing air supply passage). Compressed air is supplied through the air passage 20 and the internal passage 27 of the air piston 20.

  When the compressed air for air bearing is supplied to the air bearing air supply passage 17 and the shaft passage 31 via the compressed air source P and the air bearing air supply device PA, the air bearing type air cylinder device having the above-described configuration is slidable inside air. The compressed air ejected from the inner peripheral surface of the bearing 13 causes the piston rod 30 to float with respect to the inner diameter sliding air bearing 13, and the compressed air ejected from the outer peripheral surface of the outer diameter sliding air bearing 26 causes the air piston 20 to It floats with respect to the cylinder body 10. The air piston 20 is moved and urged to the right in the figure by an urging means (not shown) or its own weight (FIGS. 1 and 2 show the moving end to the left), and the air piston 20 is urged to the right in FIG. When the compressed air for cylinder operation is supplied into the cylinder body 10 through the compressed air source P, the piston operating air supply device PS and the piston operating air supply path 18, the air piston 20 is attached. Move to the left against force or weight. That is, it functions as a single-acting air bearing type air cylinder device.

  According to this embodiment, when the air piston 20 moves in the cylinder body 10, the air piston 20 can be moved in the radial direction with respect to the piston rod 30 by the O-ring 22, and the elastic ring 23 can move the piston. Axial relative movement with respect to the rod 30 is possible. For this reason, even if the roundness or the inner diameter of the cylinder body 10 (the difference between the inner diameter of the cylinder body 10 and the outer diameter of the air piston 20) slightly varies in the length direction (the clearance between the cylinder body 10 and the air piston 20). Even if the air piston 20 changes, the air piston 20 can follow the circularity change or clearance change without causing the air film to break.

  FIG. 3 shows the undulation of the inner wall 10S of the cylinder body 10 exaggerated. The amount of elastic deformation of the O-ring 22 and the elastic ring 23 is determined so as to cope with such swell 10S. In other words, the O-ring 22 and the elastic ring 23 can be made of, for example, a rubber material, and the elasticity and size thereof are determined so that the air piston 20 and the piston rod 30 can be relatively moved in the radial direction and the axial direction. .

  In the above, the present invention is applied to a single-acting air bearing type air cylinder device, but the present invention can also be applied to a double-acting type. 4 and 5 show another embodiment in which the present invention is applied to a double-acting air bearing type air cylinder device. In this embodiment, compressed air is ejected from the outer-diameter sliding air bearing 26 of the air piston 20 by piston operating air that moves the air piston 20, and as shown in FIG. 10), an air introduction port 28 for supplying compressed air to the outer diameter sliding air bearing 26 is opened, and the air bearing air supply device PA and the shaft passage 31 are abolished as shown in FIG. (The piston rod 30 made of a hollow pipe (having the shaft passage 31) is changed to a solid rod 30R).

  In the embodiment of FIGS. 1 and 2, the compressed air whose pressure is controlled may be simply supplied to the pressure chamber on the left side of the air piston 20. In the embodiment of FIGS. Controlled compressed air having a lower pressure than the right pressure chamber may be always supplied to the left pressure chamber. Since the pressure receiving area of the air piston 20 is larger at the left end face than at the right end face, the air piston 20 can be moved to the right even at a low pressure. The jetted compressed air can escape to the low pressure chamber side.

  In the above embodiment, the inner diameter sliding air bearing 13 is used for the projecting portion from the cylinder body 10 of the piston rod 30, and there is an advantage that the entire sliding resistance can be made zero as much as possible. It is also possible to use contact-type airtight means such as an O-ring for the projecting portion from the cylinder body 10.

DESCRIPTION OF SYMBOLS 10 Cylinder main body 11 Perforated end plate 11a Buffer member 12 End block 13 Inner diameter sliding air bearing 13a Shaft hole 14 O ring 15 Elastic ring 16 Retainer ring 17 Air bearing air supply path 18 Piston operation air supply path 20 Air piston 21 Through Hole 22 O-ring (radial elastic coupling means)
23 Elastic ring (Axial elastic coupling means)
24 End plate (fixing means, axial elastic coupling means)
25 Retainer ring (fixing means, axial elastic coupling means)
26 Outer diameter sliding air bearing 27 Internal passage 30 Piston rod 31 Axial passage 32 Radial passage P Compressed air source PA Air bearing air supply device PS Piston operating air supply device

Claims (6)

A cylinder body composed of a pipe body, an air piston provided with an air bearing for ejecting air from an outer peripheral surface fitted to the cylinder body, and a piston rod coupled to the air piston, the air piston being connected to the cylinder body In the air bearing type air cylinder device in which the entire facing surface is made of a porous body ,
A through hole formed in the shaft of the air piston;
Axial elastic coupling means for coupling the air piston and the piston rod inserted through the through-hole so as to be relatively movable in the axial direction; and the air piston and the piston rod inserted through the through-hole relative to each other in the radial direction. Radially elastic coupling means for movably coupling;
An air bearing type air cylinder device comprising:   2. The air bearing type air cylinder device according to claim 1, wherein the axial elastic coupling means includes a pair of elastic rings positioned at both ends of the air piston and fitted to the piston rod, and the pair of elastic rings connected to the air piston. An air bearing type air cylinder device having fixing means for fixing to both ends of the piston rod in a state of contact with no gap.   3. The air bearing type air cylinder device according to claim 1, wherein the radial elastic coupling means is at least a pair of elastic rings interposed between the through hole of the air piston and the piston rod with different axial positions. An air bearing type air cylinder device having   The air bearing type air cylinder device according to any one of claims 1 to 3, wherein compressed air is supplied to the air bearing of the air piston via a shaft passage formed in the piston rod. An air-bearing type air cylinder device that operates in a different route from the air route.   The air bearing type air cylinder device according to any one of claims 1 to 3, wherein compressed air is supplied to the air piston by operating the air piston through an air inlet port formed in an end surface of the air piston. Air bearing type air cylinder device that uses piston operating air.   6. The air-bearing air cylinder device according to claim 1, wherein a projecting portion of the piston rod from the cylinder body is provided with an inner-diameter sliding-type air bearing. .

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