JP2013224732A - Dust seal cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust seal cover that is easily replaced.SOLUTION: A dust seal cover 100 protects a dust seal which is in sliding contact with the outer peripheral surface of a piston rod inserted in a cylinder tube 2 so as to be capable of reciprocating and which scrapes dust adhering to the outer peripheral surface of the piston rod. The dust seal cover 100 is provided with: a cover section 25 in which a protection part 28 formed so as to cover at least a part of the dust seal faces the outer peripheral surface of the piston rod with a predetermined gap provided therebetween; a divided band 21 which holds the cover section 25 while pressing the cover section 25 against the outer peripheral surface of the cylinder tube 2; and a fastening tool 24.

Description

  The present invention relates to a dust seal cover for protecting a dust seal provided in a fluid pressure cylinder.

  As a conventional hydraulic cylinder, there is known one in which a dust seal for scraping dust adhering to an outer periphery of a piston rod is provided on an inner periphery of a cylinder head.

  Patent Document 1 discloses that an annular sub-dust seal that is in sliding contact with the outer periphery of the piston rod is provided on the opposite side of the cylinder from the dust seal.

JP 2010-116997 A

  Since the sub-dust seal described in Patent Document 1 is held by a metal holding member that is pressed by caulking the outer cylinder, it has not been easy to replace.

  The present invention has been made in view of the above problems, and an object thereof is to provide a dust seal cover that can be easily replaced.

  The present invention is a dust seal cover that protects a dust seal that slides in contact with an outer peripheral surface of a piston rod that is reciprocally inserted into a cylinder tube and scrapes dust adhering to the outer peripheral surface of the piston rod. A cover part formed so as to cover at least a part and having a tip part facing the outer peripheral surface of the piston rod with a predetermined gap, and a holder for pressing and holding the cover part against the outer peripheral surface of the cylinder tube And.

  According to the present invention, the cover portion that covers the dust seal is pressed and held by the holder on the outer peripheral surface of the cylinder tube. Therefore, the dust seal cover can be replaced simply by releasing the pressing by the holder. Therefore, the dust seal cover can be easily replaced.

It is a perspective view showing a part of fluid pressure cylinder provided with a dust seal cover concerning a 1st embodiment of the present invention. It is a top view which shows a part of fluid pressure cylinder provided with the dust seal cover which concerns on 1st Embodiment of this invention. It is sectional drawing which follows the AA line in FIG. It is a side view showing a part of fluid pressure cylinder provided with a dust seal cover concerning a 1st embodiment of the present invention. It is sectional drawing which follows the BB line in FIG. It is a perspective view which shows a part of fluid pressure cylinder provided with the dust seal cover which concerns on 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
First, the hydraulic cylinder 1 as a fluid pressure cylinder provided with the dust seal cover 100 according to the first embodiment of the present invention will be described.

  The hydraulic cylinder 1 is used as an actuator mounted on a construction machine or an industrial machine. For example, the hydraulic cylinder 1 is used as a bucket cylinder mounted on a hydraulic excavator, and the hydraulic excavator bucket rotates as the hydraulic cylinder 1 expands and contracts.

  As shown in FIG.1 and FIG.3, the hydraulic cylinder 1 is provided with the cylindrical cylinder tube 2 and the piston rod 3 inserted in the cylinder tube so that reciprocation was possible.

  One end of the piston rod 3 is connected to a piston (not shown) that is slidably inserted into the cylinder tube 2 and divides the cylinder tube 2 into a rod side chamber 4 and an anti-rod side chamber. The other end of the piston rod 3 extends to the outside of the cylinder tube 2 and is connected to the bucket via the connecting portion 3a.

  The rod side chamber 4 and the non-rod side chamber communicate with a hydraulic pump or a tank through a switching valve. When one of the rod side chamber 4 and the non-rod side chamber communicates with the hydraulic pump, the other communicates with the tank. The hydraulic cylinder 1 expands and contracts when hydraulic oil (working fluid) is guided from the hydraulic pump to the rod side chamber 4 or the non-rod side chamber and the piston rod 3 moves in the axial direction.

  As shown in FIG. 3, the end opening of the cylinder tube 2 is closed by a substantially cylindrical cylinder head 10. The piston rod 3 is slidably inserted into the cylinder head 10 and supported by the cylinder head 10.

  A dust seal 11 that slides on the outer peripheral surface of the piston rod 3 to scrape dust adhering to the outer peripheral surface of the piston rod 3 and prevents the dust from entering the cylinder tube 2 is provided on the inner peripheral surface of the cylinder head 10. Provided.

  The dust seal 11 is provided at the end of the cylinder head 10, and a part of the lip portion 11 a that scrapes dust is exposed from the cylinder head 10. Thus, since a part of the dust seal 11 is exposed from the cylinder head 10, dust from the outside can be effectively scraped off. On the other hand, a portion of the dust seal 11 exposed from the cylinder head 10 may be damaged by coming into contact with a foreign object such as a tree or a branch during work.

  In order to prevent damage to the dust seal 11, the hydraulic cylinder 1 is provided with a dust seal cover (hereinafter simply referred to as “cover”) 100 that protects the dust seal 11. Hereinafter, the cover 100 will be described in detail with reference to FIGS.

  The cover 100 has a shape along the outer peripheral surface of the cylinder tube 2 and is divided so as to be openable and closable; a fastening tool 24 for tightening the split band 21 toward the outer peripheral surface of the cylinder tube 2; And a cover portion 25 that is held by the divided band 21 and is formed so as to cover the dust seal 11. The split band 21 and the fastener 24 constitute a holder that presses and holds the cover portion 25 against the outer peripheral surface of the cylinder tube 2.

  The split band 21 includes two semicircular arc-shaped first bands 21A and second bands 21B along the outer peripheral surface of the cylinder tube 2, and one ends of the first band 21A and the second band 21B are opened and closed via pins 31. It is connected freely. The split band 21 is formed of a metal material.

  At the other end portions of the first band 21A and the second band 21B, flange portions 22a and 22b extending in the radial direction of the cylinder tube 2 and facing each other are formed. Holes through which the bolts 32 are inserted are formed in the flange portions 22a and 22b. A nut 33 is fastened to the bolt 32. By tightening the bolt 32 and the nut 33, the flange portions 22a and 22b are sandwiched between the head portion 32a of the bolt 32 and the nut 33, and the first band 21A and the second band 21B are directed toward the outer peripheral surface of the cylinder tube 2. Tightened. The fastening tool 24 is constituted by the bolt 32 and the nut.

  The cover portion 25 is reduced in diameter toward the pressure receiving portion 26 pressed against the outer peripheral surface of the cylinder tube 2 by the divided band 21, the flat plate portion 27 along the end surface of the cylinder head 10, and the outer peripheral surface of the piston rod 3. And a protective portion 28 that is formed in a conical surface shape and covers and protects the dust seal 11. The cover portion 25 is formed of a casting material, and the pressure receiving portion 26, the flat plate portion 27, and the protection portion 28 are integrally formed.

  The pressure receiving portion 26 has an arc shape having an inner diameter substantially the same as the outer diameter of the cylinder tube 2, and the inner peripheral surface is in close contact with the outer peripheral surface of the cylinder tube 2 when pressed by the divided band 21. As described above, the cover portion 25 is held by the divided band 21 when the pressure receiving portion 26 is pressed against the outer peripheral surface of the cylinder tube 2 by the divided band 21.

  The cover part 25 includes two first cover parts 25A and a second cover part 25B, and is divided and held in a first band 21A and a second band 21B. You may make it couple | bond the division | segmentation band 21 and the pressure receiving part 26 of the cover part 25 via an adhesive material. In that case, the first cover portion 25A and the second cover portion 25B are also opened and closed as the first band 21A and the second band 21B are opened and closed.

  The gap 40 between the end surfaces of the first cover portion 25A and the second cover portion 25B facing each other is preferably as small as possible in order to prevent foreign matter from entering the cover portion 25.

  The protection portion 28 extends toward the outer peripheral surface of the piston rod 3 in order to prevent foreign matter from entering the cover portion 25, and the tip portion is opposed to the outer peripheral surface of the piston rod 3 with a predetermined gap 41. To do. It is desirable that the gap 41 is as small as possible from the viewpoint of preventing foreign matter from entering the cover portion 25. However, since the clearance 41 is small, when the protection part 28 is deformed by receiving an external force, the tip of the protection part 28 comes into contact with the outer peripheral surface of the piston rod 3 and is damaged. In order to prevent such a situation, the protection part 28 is formed of a casting material that is a brittle material, and is configured to be damaged without being deformed according to the magnitude of the acting external force. That is, the protection part 28 is damaged without coming into contact with the outer peripheral surface of the piston rod 3 when receiving an external force larger than a predetermined magnitude. Therefore, it is possible to prevent the outer peripheral surface of the piston rod 3 from being damaged even though the gap 41 between the front end portion of the protective portion 28 and the outer peripheral surface of the piston rod 3 is small.

  Since there is a gap 41 between the tip of the protection part 28 and the outer peripheral surface of the piston rod 3, there is a possibility that foreign matters such as soil and sand may enter the cover part 25 through the gap 41. As a countermeasure, it is desirable that the protective portion 28 is not formed all around, but is formed by opening a part of the protective portion 28. Specifically, as shown in FIG. 5, the protective portions 28 of the first cover portion 25 </ b> A and the second cover portion 25 </ b> B are formed over approximately 120 degrees, so that the protective portion 28 extends over 120 degrees. Thus, an opening 42 is formed. Foreign matter that has entered the cover 25 through the opening 42 is discharged to the outside. As described above, the cover portion 25 is formed so as to cover at least a part of the dust seal 11.

  In order to promote the discharge of foreign matter from the opening 42, it is desirable to attach the cover 100 to the hydraulic cylinder 1 so that the opening 42 faces vertically downward. A part of the dust seal 11 is exposed to the outside by the open part 42, but by attaching the cover 100 so that the open part 42 faces vertically downward, the exposed part faces vertically downward. There is little possibility of contact and damage. On the other hand, the upper side of the dust seal 11 that is likely to come into contact with foreign matters such as trees and branches is covered with the protective portion 28 over 240 degrees, so that damage is prevented. In this way, by attaching the cover 100 to the hydraulic cylinder 1 so that the opening 42 faces vertically downward, it is possible to achieve both the discharge of foreign matter that has entered the cover 25 and the prevention of damage to the dust seal 11.

  1 to 5 show a shape in which the entire first cover portion 25A and second cover portion 25B are formed over 120 degrees. However, the pressure receiving portion 26 may be formed over 180 degrees. If comprised in this way, since the contact area of the pressure receiving part 26 and the cylinder tube 2 will become large, 25 A of 1st cover parts and the 2nd cover part 25B can be fixed to the cylinder tube 2 firmly.

  Further, a gap 50 (see FIG. 5) is formed between the inner peripheral surfaces of the first band 21A and the second band 21B and the outer peripheral surface of the cylinder tube 2 over 120 degrees. A gap filling member that fills the gap may be disposed in the gap 50. By arranging the gap filling member in the gap 50, the first cover portion 25A and the second cover portion 25B can be positioned in the circumferential direction.

  Next, a method for attaching and removing the cover 100 to / from the cylinder tube 2 will be described.

  While the pressure receiving portions 26 of the first cover portion 25A and the second cover portion 25B are in contact with the outer peripheral surface of the cylinder tube 2, the first band 21A and the second band 21B are closed via the pin 31 and the bolt 32 By tightening the nut 33, the first band 21 </ b> A and the second band 21 </ b> B are tightened toward the outer peripheral surface of the cylinder tube 2. Thereby, the pressure receiving part 26 is pressed by the first band 21 </ b> A and the second band 21 </ b> B, and the inner peripheral surface is in close contact with the outer peripheral surface of the cylinder tube 2. In this way, the cover 100 is attached to the cylinder tube 2, and the dust seal 11 is covered and protected by the cover portion 25.

  The cover 100 is removed by releasing the tightening by the bolt 32 and the nut 33 and opening the first band 21 </ b> A and the second band 21 </ b> B through the pin 31.

  As described above, the cover 100 is configured to be detachable from the cylinder tube 2.

  According to the above 1st Embodiment, there exists an effect shown below.

  Since the dust seal 11 exposed from the cylinder head 10 is covered with the cover portion 25, damage to the dust seal 11 can be prevented even when working in an environment where branches and sharp leaves are around. .

  Moreover, since the cover part 25 which covers the dust seal 11 is held by the split band 21 that can be freely opened and closed, the cover 100 can be replaced simply by releasing the tightening by the fastening tool 24 and opening the split band 21. Therefore, the cover 100 can be easily replaced.

  Further, since the protection part 28 is formed of a casting material which is a brittle material and breaks without being deformed according to the magnitude of the acting external force, even when an excessive external force acts on the protection part 28. The damage to the outer peripheral surface of the piston rod 3 can be prevented.

  In addition, since the protective portion 28 is partially opened, even if foreign matter enters the cover portion 25, the foreign matter can be discharged.

  Next, a modification of the first embodiment is shown.

  In the first embodiment described above, it has been described that the cover portion 25 is formed of a casting material. Instead of this, the cover portion 25 may be formed of a resin material. In this case, the protection portion 28 deforms and contacts the outer peripheral surface of the piston rod 3 when receiving an external force of a predetermined magnitude or larger, but when the external force is removed, the protection portion 28 returns to its original shape. Therefore, the tip of the protection part 28 does not continue to contact the outer peripheral surface of the piston rod 3.

Second Embodiment
Next, a cover 200 according to a second embodiment of the present invention will be described with reference to FIG. Below, it demonstrates centering on a different point from the cover 100 which concerns on the said 1st Embodiment, the same code | symbol is attached | subjected to the structure which has the same function as the said 1st Embodiment, and description is abbreviate | omitted.

  The cover 200 is different from the cover 100 according to the first embodiment in that the cover portion 25 is not divided. In addition, the cover 200 is configured so that the holder that presses and holds the cover portion 25 against the outer peripheral surface of the cylinder tube 2 is tightened so that the band 60 and the band 60 are tightened toward the outer peripheral surface of the cylinder tube 2. The cover 61 is also different from the cover 100 according to the first embodiment in that it is configured by the attachment 61.

  The pressure receiving part 26, the flat plate part 27, and the protection part 28 of the cover part 25 are formed over approximately 120 degrees, whereby an open part 42 is formed in the cover part 25. Thus, the cover part 25 is formed with a part opened. When the cover portion 25 is attached to the outer peripheral surface of the cylinder tube 2, first, the piston rod 3 is inserted into the cover portion 25 through the opening portion 42, and then the inner surface of the flat plate portion 27 is placed on the cylinder head 10. The cover portion 25 is moved in the axial direction of the piston rod 3 until it comes into contact with the end surface.

  In order to promote the discharge of foreign matter from the opening 42, it is desirable to attach the cover 100 to the hydraulic cylinder 1 so that the opening 42 faces vertically downward. Thus, the opening part 42 is formed for mounting the cover part 25 and discharging foreign matter.

  The band 60 is formed by bending an elongated metal plate into a shape along the outer peripheral surface of the cylinder tube 2. The band 60 is wound along the outer peripheral surface of the pressure receiving portion 26 of the cover portion 25, and the vicinity of both ends is bound and tightened by the fastening tool 61. Thus, the cover part 25 is pressed against the outer peripheral surface of the cylinder tube 2 by the band 60.

  According to the above 2nd Embodiment, there exists an effect shown below.

  Since the cover portion 25 covering the dust seal 11 is pressed and held by the band 60 and the fastening tool 61 on the outer peripheral surface of the cylinder tube 2, the cover 200 is replaced by releasing the fastening by the fastening tool 61. It can be done simply by loosening. Therefore, the cover 200 can be easily replaced.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

    For example, the cover unit 25 including the first band 21A and the second band 21B in the first embodiment is held by the holder 61 configured by the band 60 and the fastening tool 61 in the second embodiment. It may be. Moreover, you may make it hold | maintain the cover part 25 which is not divided | segmented in the said 2nd Embodiment with the holder comprised by the division | segmentation band 21 and the fastener 24 in the said 1st Embodiment.

100, 200 Dust seal cover 1 Hydraulic cylinder 2 Cylinder tube 3 Piston rod 10 Cylinder head 11 Dust seal 21 Split band 21A First band 21B Second band 24 Fastening tool 25 Cover part 25A First cover part 25B Second cover part 26 Pressure receiving part 27 Flat part 28 Protective part 31 Pin 32 Bolt 33 Nut 40 Gap 41 Gap 42 Open part 60 Band 61 Fastening tool

Claims (5)

A dust seal cover that protects a dust seal that slides in contact with an outer peripheral surface of a piston rod that is reciprocally inserted into a cylinder tube and scrapes off dust adhering to the outer peripheral surface of the piston rod,
A cover part that is formed so as to cover at least a part of the dust seal, and whose front end part faces the outer peripheral surface of the piston rod with a predetermined gap;
A holder for pressing and holding the cover portion against the outer peripheral surface of the cylinder tube;
A dust seal cover comprising:   The dust seal cover according to claim 1, wherein a part of the cover part is opened.   3. The dust seal cover according to claim 1, wherein the cover portion is made of a brittle material, and is broken without being deformed according to the magnitude of an external force acting thereon. The holder is
A split band having a shape along the outer peripheral surface of the cylinder tube and split openably and closably;
A clamp for tightening the divided band toward the outer peripheral surface of the cylinder tube,
4. The dust seal cover according to claim 1, wherein the cover portion is held by being pressed against an outer peripheral surface of the cylinder tube by the divided band. 5.   The dust seal cover according to any one of claims 1 to 4, wherein the cover portion is divided and formed.

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