JP2011226567A - Dust removal structure used for fluid pressure cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly and stably remove dust attached to a piston rod in a fluid pressure cylinder to prevent ingression into a cylinder body.SOLUTION: An end part of a cylinder tube 12 constituting the fluid pressure cylinder 10 includes a rod cover 14, and the piston rod 18 is inserted through a rod hole 42 of the rod cover 14. The rod cover 14 includes: a scraper 58 through an installation groove 50 formed in the inner circumferential face; and an annular ring body 66 installed inside the scraper. The scraper 58 is cross-sectionally formed in a U shape from a resin material having self-lubricity, and the ring body 66 formed in a cross-sectionally circular shape from an elastic material is inserted thereinside. An inner cylinder part 64 of the scraper 58 slidingly contacts with the outer circumferential face 18a of the piston rod 18, and the inner cylinder part 64 is pressed on the outer circumferential face 18a side by elastic force of the ring body 66.

Description

  The present invention relates to a dust removing structure that is used in a fluid pressure cylinder that displaces a piston along the inside of a cylinder body under the action of supplying a pressure fluid, and prevents dust and the like from entering the cylinder body.

  2. Description of the Related Art Conventionally, a fluid pressure cylinder having a piston that is displaced under the action of supplying a pressure fluid has been used as a conveying means for a workpiece or the like.

  In such a fluid pressure cylinder, a piston is slidably provided in a cylinder chamber defined inside a cylindrical cylinder body, and a head cover and a rod cover are respectively attached to both ends of the cylinder body. The room is blocked. Further, an axial piston rod is connected to the piston, and is supported so as to be displaceable by being inserted through a rod cover. Further, in the fluid pressure cylinder, when the piston is displaced to the rod cover side, the piston rod protrudes outside through the rod cover and is exposed, and dust or the like may adhere to the outer peripheral surface of the piston rod. Therefore, a scraper is mounted on the inner peripheral surface of the rod cover for the purpose of removing such dust, and the scraper is in sliding contact with the outer peripheral surface of the piston rod.

  When the piston rod is pulled into the cylinder tube, for example, dust attached to the outer peripheral surface of the piston rod is removed by a scraper provided inside the rod cover (see, for example, Patent Document 1).

JP 2007-218339 A

  The scraper as described above is generally made of an elastic material such as rubber, and is brought into sliding contact with the outer peripheral surface of the piston rod using the elastic force of the elastic material. However, with only the elastic force of the elastic material, it is difficult to stably press the scraper against the piston rod for a long time. As a result, when the pressing force of the scraper becomes unstable or insufficient, there is a concern that dust or the like may enter the cylinder body together with the piston rod without being sufficiently removed.

  In addition, when removing dust and the like attached to the outer peripheral surface by sliding the scraper against the piston rod, there is a concern that the lubricant applied for the purpose of lubricating the outer peripheral surface may be removed at the same time. As a result, it is assumed that the lubricity between the piston rod and the rod cover decreases. In this case, the displacement resistance when the piston including the piston rod is displaced increases, making it difficult to smoothly displace.

  The present invention has been made in consideration of the above-described problems, and is a dust removal structure used for a fluid pressure cylinder that can reliably and stably remove dust attached to a piston rod and prevent entry into a cylinder body. The purpose is to provide.

In order to achieve the above object, the present invention provides a cylinder main body into which pressure fluid is introduced, a piston provided inside the cylinder main body so as to be displaceable, and an outside of the cylinder main body connected to the piston. Dust removal for removing dust adhering to the piston rod in a hydraulic cylinder provided with a piston rod that is displaced so as to protrude toward the cylinder and a rod cover that is provided on the cylinder body and holds the piston rod in a displaceable manner Structure,
The rod cover is formed from a resin material so as to be elastically deformable, and a scraper that is in sliding contact with the outer peripheral surface of the piston rod;
An elastic member provided inside the scraper and having elasticity for pressing the scraper toward the outer peripheral surface side;
It is characterized by providing.

  According to the present invention, in the rod cover constituting the fluid pressure cylinder, a scraper is provided which is made of a resin material and is slidably contacted with the outer peripheral surface of the piston rod held by the rod cover so as to be displaceable. An elastic member having elasticity is provided. Further, the scraper is formed to be elastically deformable, while the elastic member has elasticity capable of pressing the scraper toward the outer peripheral surface side of the piston rod.

  Accordingly, when the scraper is brought into sliding contact with the outer peripheral surface of the piston rod, the scraper can be suitably pressed toward the outer peripheral surface by the elasticity of the elastic member, so that the scraper can be slid reliably and stably. Is possible. As a result, the dust removing function by the scraper can be stably obtained over a long period of time, and the dust attached to the outer peripheral surface of the piston rod can be reliably removed and prevented from entering the cylinder body.

  Moreover, it is good to form a scraper in the cross-sectional U-shape opened in the displacement direction of the piston rod. Furthermore, the elastic member may be formed in a ring shape having a circular cross section.

  Furthermore, by forming the scraper from a resin material having self-lubricating property, sliding resistance when sliding on the outer peripheral surface of the piston rod can be reduced. For example, lubrication on the outer peripheral surface is possible. Even if this is insufficient, the piston rod can be displaced smoothly.

  Furthermore, a coating layer may be provided on the outer peripheral surface of the piston rod. As a result, the contact resistance between the outer peripheral surface of the piston and the scraper is further reduced by the coating layer, the piston rod can be displaced more smoothly, and the rust prevention and durability of the piston rod can be improved. Can be improved.

  The rod cover may include a holding space that faces the outer peripheral surface of the piston rod and holds a lubricant that lubricates the outer peripheral surface. Thus, the lubricant can be stably held in the holding space for a long period of time, and dust or the like attached to the outer peripheral surface of the piston rod by the lubricant can be taken in and removed.

  According to the present invention, the following effects can be obtained.

  That is, in the rod cover constituting the fluid pressure cylinder, a scraper is provided which is made of a resin material and is slidably contacted with the outer peripheral surface of the piston rod held by the rod cover so as to be displaceable, and the scraper has elasticity inside. By providing the elastic member, when the scraper is brought into sliding contact with the outer peripheral surface of the piston rod, the scraper can be suitably pressed to the outer peripheral surface side by the elasticity of the elastic member. It is possible to make sliding contact. As a result, the dust removing function by the scraper can be stably obtained over a long period of time, and the dust attached to the outer peripheral surface of the piston rod can be reliably removed and prevented from entering the cylinder body.

1 is an overall cross-sectional view of a fluid pressure cylinder to which a dust removing structure according to an embodiment of the present invention is applied. It is an expanded sectional view which shows the vicinity of the rod cover in FIG.

  A preferred embodiment of a dust removing structure used for a fluid pressure cylinder according to the present invention will be described in detail below with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 indicates a fluid pressure cylinder to which the dust removing structure according to the embodiment of the present invention is applied.

  As shown in FIG. 1, the fluid pressure cylinder 10 includes a bottomed cylindrical cylinder tube (cylinder main body) 12, a rod cover 14 attached to one end of the cylinder tube 12, and the cylinder tube 12. A piston 16 that is displaceable inside, a piston rod 18 that is connected to the piston 16 and that is displaceably supported by the rod cover 14, and a dust removal mechanism 20 that can remove dust and the like adhering to the piston rod 18. Including.

  The cylinder tube 12 has a cylinder hole 22 extending along the axial direction (arrow A, B direction) at the center thereof, and the cylinder hole 22 is on one end side of the cylinder tube 12 (arrow A direction). It is open at. On the other hand, a wall 24 is formed integrally with the other end of the cylinder tube 12 to close the cylinder hole 22.

  Further, a first port 26 and a second port 28 through which pressure fluid is supplied and discharged are formed on the outer surface of the cylinder tube 12. The first port 26 is provided near one end of the cylinder tube 12, while the second port 28 is provided near the other end of the cylinder tube 12. Connected to the source. The first and second ports 26 and 28 communicate with the cylinder hole 22 through a communication passage 30 extending toward the cylinder hole 22 side.

  The rod cover 14 has a small-diameter portion 32 and a large-diameter portion 34 adjacent to the small-diameter portion 32, and the small-diameter portion 32 is disposed on the wall portion 24 side (arrow B direction) in the cylinder tube 12. Is done. A stepped portion formed between the small diameter portion 32 and the large diameter portion 34 is engaged with a step formed at one end portion of the cylinder hole 22 to be positioned with respect to the cylinder hole 22. The Further, the rod cover 14 is attached to the annular groove formed in the inner peripheral surface of the cylinder hole 22, so that the locking ring 40 comes into contact with the end surface 34 a of the large diameter portion 34, and The rod cover 14 is fixed in a state in which the rod cover 14 is prevented from moving toward the opening side (arrow A direction) of the cylinder hole 22.

  Further, as shown in FIGS. 1 and 2, a rod hole 42 penetrating along the axial direction (arrows A and B directions) is formed in the center portion of the rod cover 14, and a piston hole is formed in the rod hole 42. The rod 18 is inserted. That is, the rod hole 42 is formed so as to penetrate the small diameter portion 32 and the large diameter portion 34. On the other hand, an O-ring 44 is attached to the outer peripheral surface of the small-diameter portion 32 via an annular groove and is in contact with the inner peripheral surface of the cylinder hole 22.

  On the other hand, a rod packing 48 is mounted on the inner peripheral surface of the rod hole 42 via a packing groove 46 formed at a position on the inner peripheral side of the small diameter portion 32. The rod packing 48 is formed, for example, from an elastic material such as rubber in a V-shaped cross section and in an annular shape, and is arranged so that the opened portion is on the piston 16 side (arrow B direction).

  Further, a dust removing mechanism 20 is provided on the inner peripheral surface of the rod hole 42, and an annular mounting groove 50 opened toward the end surface 34a side (arrow A direction) of the large diameter portion 34 is formed. The mounting groove 50 includes a first groove portion 52 formed on the end surface 34a side (arrow A direction) of the large diameter portion 34, a second groove portion 54 formed on the rod packing 48 side (arrow B direction), and the first groove portion. It consists of an insertion port 56 formed between the groove 52 and the end face.

  The first groove portion 52 has a substantially rectangular cross section and is formed with a larger diameter than the packing groove 46 in which the rod packing 48 is mounted, and a scraper 58 formed in an annular shape with a U-shaped cross section is mounted therein. The scraper 58 is formed of, for example, a resin material having self-lubricating properties, and has an outer cylindrical portion 60 that contacts the outer peripheral surface of the first groove portion 52 and a radius that is bent at a right angle with respect to the outer cylindrical portion 60. The connecting portion 62 extends in the inward direction, and the inner tubular portion 64 is bent with respect to the connecting portion 62 and is inclined at a predetermined angle toward the radially inward direction. In other words, the inner cylinder part 64 is inclined so as to gradually move away from the outer cylinder part 60 with the portion connected to the connection part 62 as a base point.

  The scraper 58 is formed such that the inner cylinder part 64 and the outer cylinder part 60 protrude in substantially the same direction with respect to the connection part 62, and the inner cylinder part 64 is based on the connection part with the connection part 62. Further, it has a resilience in the direction approaching / separating from the outer cylinder part 60 (the direction of arrow C in FIG. 2), that is, in the radial direction.

  The scraper 58 is mounted so as to open toward the end surface 34 a side (arrow A direction) of the large-diameter portion 34, and the tip of the inner cylinder portion 64 is inserted into the rod hole 42 under the elastic action of the scraper 58. The piston rod 18 is inserted into the outer peripheral surface 18a of the piston rod 18 and is pressed and slidably contacted. At this time, the tip of the inner cylinder portion 64 is pressed obliquely with a predetermined pressure against the outer peripheral surface 18 a of the piston rod 18.

  On the other hand, inside the scraper 58, for example, a ring body 66 formed in a circular cross section from an elastic material such as rubber is provided. Specifically, the ring body 66 is mounted such that the outer peripheral surface thereof abuts against the outer cylinder part 60, the inner cylinder part 64, and the connection part 62.

  The cross-sectional diameter D of the ring body 66 is set to be larger than the separation distance L between the outer cylinder part 60 and the inner cylinder part 64 in the scraper 58 (D> L in FIG. 2). Specifically, the outer peripheral surface of the ring body 66 is formed with a cross-sectional diameter D that can press the outer cylinder part 60 and the inner cylinder part 64 in a direction away from each other in a state of abutting the connection part 62 in the scraper 58. The outer cylinder part 60 and the inner cylinder part 64 are mounted in a slightly crushed state.

  The second groove portion 54 extends toward the rod packing 48 side (in the direction of arrow B) with respect to the side surface of the first groove portion 52, and is formed with a smaller diameter than the inner peripheral diameters of the first groove portion 52 and the packing groove 46. The Then, in a space (holding space) 68 provided between the second groove portion 54, the inner cylindrical portion 64 of the scraper 58, and the outer peripheral surface 18a of the piston rod 18, a lubricant 70 having a viscosity such as grease is provided. Filled. That is, the second groove portion 54 functions as a filling space filled with the lubricant 70 that performs lubrication between the piston rod 18 and the rod cover 14.

  As a result, the outer peripheral surface 18 a of the piston rod 18 is covered with the lubricant 70 in the rod hole 42, and the lubricant 70 is applied to the outer peripheral surface 18 a by passing through the space 68.

  The insertion port 56 is formed with a diameter slightly smaller than the inner peripheral diameter of the first groove portion 52 and gradually increases from the first groove portion 52 toward the end surface 34a side (in the direction of arrow A) of the large diameter portion 34. Is formed to expand. That is, the inner peripheral diameter of the insertion port 56 is set so that the first groove 52 side (arrow B direction) is the smallest. In this way, by forming the insertion port 56 smaller than the inner peripheral diameter of the first groove portion 52, the scraper 58 attached to the first groove portion 52 is prevented from being pulled out through the insertion port 56. The In addition, when the insertion port 56 is tapered so that the diameter gradually decreases toward the first groove 52 (in the direction of arrow B), the scraper 58 and the ring body 66 are inserted into the first groove 52. It becomes easy.

  That is, the scraper 58, the ring body 66, and the lubricant 70 described above function as a dust removing mechanism 20 that can remove dust and the like attached to the outer peripheral surface 18a of the piston rod 18.

  The piston 16 is formed in a circular cross section, and a piston packing 72 and a magnetic body 74 are attached to the outer peripheral surface of the piston 16 via an annular groove. The piston packing 72 is slidably contacted with the inner peripheral surface of the cylinder hole 22 to prevent leakage of the pressure fluid between the cylinder hole 22 and the piston 16, while being provided on the outer surface of the cylinder tube 12. By detecting the position of the magnetic body 74 by a position detection sensor (not shown), the displacement position and displacement amount of the piston 16 in the cylinder tube 12 are confirmed.

  On the other hand, one end portion of the piston rod 18 is inserted into a substantially central portion of the piston 16 through a hole portion 76 penetrating along the axial direction (arrows A and B directions) and crimped. The piston rod 18 is connected so as not to protrude from the end of the piston 16.

  The piston rod 18 is formed with a substantially constant diameter, and one end connected to the piston 16 is formed with a reduced diameter. The outer peripheral surface 18a of the piston rod 18 is provided with a coating layer coated with, for example, a fluororesin. When the piston rod 18 is inserted into the rod hole 42, the rod packing 48 is in sliding contact with the outer peripheral surface 18a.

  The fluid pressure cylinder 10 to which the dust removing structure according to the embodiment of the present invention is applied is basically configured as described above. Next, its operation and effects will be described. Here, the state in which the piston 16 shown in FIG. 1 is displaced toward the wall 24 side (arrow B direction) of the cylinder tube 12 will be described as an initial position.

  First, in this initial position, the pressure fluid is supplied from the pressure fluid supply source (not shown) to the second port 28, whereby the pressure fluid is supplied to the cylinder hole 22 through the communication passage 30, and the piston 16 and the wall The piston 16 is pressed and displaced toward the rod cover 14 (in the direction of arrow A) by the pressure fluid supplied to the portion 24. In this case, the first port 26 is open to the atmosphere. As a result, the piston rod 18 is displaced together with the piston 16 in a direction away from the wall portion 24 (arrow A direction), and gradually protrudes to the outside with respect to the rod cover 14, and the end surface of the piston 16 becomes the rod cover. 14 is brought into contact with the end face of the small-diameter portion 32 to be a displacement end position.

  At this time, since the outer peripheral surface 18a of the piston rod 18 is lubricated by the lubricant 70 filled on the inner peripheral side of the second groove portion 54 and the scraper 58, the sliding resistance of the piston rod 18 is reduced and smoothly displaced. Can be made. Specifically, the contact resistance between the outer peripheral surface 18a of the piston rod 18 and the inner cylindrical portion 64 of the scraper 58 is reduced.

  Next, when the piston 16 is returned from the displacement end position to the initial position again, the pressure fluid supplied to the second port 28 is supplied to the first port 26 via a switching device (not shown). By doing so, the piston 16 is gradually pressed in the direction away from the rod cover 14 (arrow B direction) by the pressure fluid supplied to the cylinder hole 22 through the communication passage 30. In this case, the second port 28 is open to the atmosphere.

  As the piston 16 is displaced, the piston rod 18 is gradually displaced so as to be accommodated in the rod cover 14. At this time, since the inner cylinder portion 64 of the scraper 58 is in sliding contact with the outer peripheral surface 18a of the piston rod 18, while the piston 16 continues to be displaced toward the wall portion 24 side (arrow B direction), Dust and the like adhering to the outer peripheral surface 18a of the piston rod 18 are continuously removed by the tip of the inner cylindrical portion 64, and in the cylinder hole 22 through the small diameter portion 32 of the rod cover 14 in a state where the dust and the like are removed. Gradually detained.

  The inner cylinder portion 64 presses the outer peripheral surface 18a of the piston rod 18 with a predetermined pressure by the elastic force of the ring body 66 provided inside the scraper 58 in addition to the elastic force of the scraper 58.

  Further, dust or the like that is not completely removed by the scraper 58 and remains on the outer peripheral surface 18a of the piston rod 18 passes through the space 68 adjacent to the scraper 58 to the lubricant 70 filled in the space 68. As a result of the contact, the lubricant 70 is taken in and removed from the viscous lubricant 70. As a result, the piston rod 18 from which dust and the like have been removed by the scraper 58 and the lubricant 70 is gradually accommodated in the cylinder hole 22.

  Then, when the piston 16 comes into contact with the wall portion 24 in the cylinder tube 12, the supply of the pressure fluid is stopped and the initial position is obtained.

  As described above, in the present embodiment, the scraper 58 provided in the mounting groove 50 of the rod cover 14 is formed from a resin material having a self-lubricating property, so that it slides on the outer peripheral surface 18a of the piston rod 18. In this case, the sliding resistance can be reduced. For example, the piston 16 and the piston rod 18 can be smoothly displaced even when the amount of the lubricant 70 applied on the outer peripheral surface 18a is small.

  Further, a ring body 66 having elasticity is mounted inside the scraper 58, and the elastic force of the ring body 66 urges the inner cylindrical portion 64 of the scraper 58 toward the outer peripheral surface 18a side of the piston rod 18. By providing so that the elastic force of the ring body 66 can be applied in addition to the elastic force of the inner cylinder part 64, the inner cylinder part 64 can be applied to the outer peripheral surface 18 a of the piston rod 18. It becomes possible to press with a stable pressing force. As a result, the dust removing function by the scraper 58 can be stably obtained over a long period of time.

  In other words, even when the elastic force of the scraper 58 is reduced, the inner cylindrical portion 64 of the scraper 58 is pressed toward the outer peripheral surface 18a of the piston rod 18 by the elastic force of the ring body 66, so that the piston rod 18 Can be stably slidably contacted.

  Furthermore, by providing a space 68 filled with the lubricant 70 on the inner peripheral surface of the rod cover 14, the lubricant 70 can be stably held in the space 68 for a long period of time and has a viscosity. By using the lubricant 70, the dust or the like adhering to the outer peripheral surface 18a of the piston rod 18 can be taken in and removed.

  Furthermore, by providing a coating layer coated with, for example, a fluororesin on the outer peripheral surface 18a of the piston rod 18, contact resistance between the outer peripheral surface 18a and the scraper 58 is further reduced by the coating layer, and the piston The rod 18 can be displaced more smoothly, and the rust prevention and durability of the piston rod 18 can be improved.

  Note that the dust removing structure used in the fluid pressure cylinder according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Fluid pressure cylinder 12 ... Cylinder tube 14 ... Rod cover 16 ... Piston 18 ... Piston rod 20 ... Dust removal mechanism 22 ... Cylinder hole 32 ... Small diameter part 34 ... Large diameter part 42 ... Rod hole 50 ... Mounting groove 52 ... 1st Groove 54 ... second groove 56 ... insertion slot 58 ... scraper 60 ... outer cylinder 64 ... inner cylinder 66 ... ring body 68 ... space 70 ... lubricant

Claims (6)

A cylinder body into which a pressure fluid is introduced; a piston provided inside the cylinder body so as to be displaceable; a piston rod connected to the piston and displaced so as to protrude outside the cylinder body; and the cylinder A fluid pressure cylinder provided on a main body and provided with a rod cover for holding the piston rod so as to be displaceable, and a dust removing structure for removing dust adhering to the piston rod,
The rod cover is formed from a resin material so as to be elastically deformable, and a scraper that is in sliding contact with the outer peripheral surface of the piston rod;
An elastic member provided inside the scraper and having elasticity for pressing the scraper toward the outer peripheral surface side;
A dust removing structure for use in a fluid pressure cylinder. In the dust removal structure according to claim 1,
The dust removing structure used for a fluid pressure cylinder, wherein the scraper is formed in a U-shaped cross section that opens in a displacement direction of the piston rod. In the dust removal structure according to claim 1 or 2,
The dust removing structure used in a fluid pressure cylinder, wherein the elastic member is formed in a ring shape having a circular cross section. In the dust removal structure according to any one of claims 1 to 3,
The dust removing structure used in a fluid pressure cylinder, wherein the scraper is formed of a resin material having self-lubricating properties. In the dust removal structure according to any one of claims 1 to 4,
A dust removing structure used for a fluid pressure cylinder, wherein a coating layer is provided on an outer peripheral surface of the piston rod. In the dust removal structure according to any one of claims 1 to 5,
A dust removing structure for use in a fluid pressure cylinder, wherein the rod cover includes a holding space that faces an outer peripheral surface of the piston rod and holds a lubricant that lubricates the outer peripheral surface.

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