JP2016125620A - Dust seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a dust seal to have a function for protecting a lip part to reduce the number of components needed for protecting the dust seal.SOLUTION: A dust seal 14 comprises: a reinforcement ring 21 provided at the inner peripheral side of a cylinder head 11; and a seal body 30 including a lip part 33, which is integrally formed with the inner peripheral side of the reinforcement ring 21, and formed by an elastic body. The reinforcement ring 21 includes: a cylindrical part 22 attached to the inner periphery side of the cylinder head 11; a diameter reduction part 23 in which its diameter reduces from a cylinder extension side end part of the cylinder part 22 toward a piston rod 20; and a protruding part 24 protruding further than the lip part 33 from the smallest diameter side of the diameter reduction part 23 in a cylinder extension direction. The protruding part 24 covers the lip part 33 from the outer periphery side of the piston rod 20 to protect the lip part 33.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a dust seal provided in a hydraulic cylinder of a work machine or the like.

  When a work machine equipped with an attachment including a boom, an arm, a bucket, and a hydraulic cylinder that operates these performs work such as excavation, dust adheres to the outer peripheral surface of the piston rod of the hydraulic cylinder.

  The dust seal is attached inside the cylinder tube, scrapes off dust adhering to the outer peripheral surface of the piston rod, and prevents the dust from entering the hydraulic cylinder.

  A dust seal cover for protecting such a dust seal has been devised.

  In Patent Document 1, a protection part formed so as to cover at least a part of the dust seal presses the cover part against the outer peripheral surface of the cylinder tube and the cover part facing the outer peripheral surface of the piston rod with a predetermined gap. And a holding tool for holding.

JP 2013-224732 A

  The dust seal cover described in Patent Document 1 is configured to be attached to the outer peripheral surface of the cylinder tube. When the hydraulic cylinder size is different, a cover in which the combination of the outer diameter of the cylinder tube and the outer diameter of the rod is separately prepared. Therefore, there is a problem that the number of parts increases.

  Therefore, the present invention provides a dust seal having a function of protecting itself instead of the dust seal cover.

The present invention relates to a cylindrical cylinder tube, a cylindrical cylinder head attached to an opening end of the cylinder tube, and a piston rod that penetrates the cylinder head and is reciprocally inserted into the cylinder tube. A dust seal that scrapes off dust adhering to the outer peripheral surface of the piston rod,
The dust seal is composed of a reinforcing ring mounted on the inner peripheral side of the cylinder head and an elastic seal body integrally formed on the inner peripheral side of the reinforcing ring,
The seal body includes a lip portion that is in sliding contact with the outer peripheral surface of the piston rod, and a part of the seal body projects from the cylinder head in the cylinder extending direction.
The reinforcing ring includes a cylindrical portion that is mounted on the inner peripheral side of the cylinder head, a reduced diameter portion that decreases in diameter from the cylinder extension side end portion side of the cylindrical portion toward the piston rod, and the reduced diameter portion. From the minimum diameter side, a protrusion that protrudes in the cylinder extending direction beyond the lip is provided.

  In this configuration, a part of the protruding lip portion is covered and protected by the protruding portion so as to be wrapped from the outer peripheral side of the piston rod.

  In addition, since the dust seal diameter is determined by the piston rod diameter, one dust seal can be configured to be attachable to a plurality of hydraulic cylinders having the same rod diameter.

  Furthermore, in the present invention, it is desirable to provide an opening diameter-reduced portion that is diameter-reduced toward the outer peripheral surface of the piston rod at the opening end portion of the protruding portion.

  In this configuration, the end of the lip is protected by the reduced diameter portion by reducing the diameter of the opening end of the protruding portion and providing the opening reduced diameter portion. The protection function of the part can be enhanced.

  According to the present invention, the dust seal itself can have a function of protecting the lip portion instead of the dust seal cover, and the number of parts protecting the dust seal can be reduced.

It is a schematic side view of the working machine provided with the cylinder used as the application object of this invention. It is a sectional side view of the cylinder which concerns on 1st Embodiment of this invention. FIG. 3 is an enlarged view of a portion A in FIG. 2. It is a sectional side view of the cylinder which concerns on 2nd Embodiment of this invention, and is an enlarged view of the location corresponded to A part of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The dust seal 14 according to the first embodiment of the present invention will be described.

  Referring to FIG. 1, a work machine 1 includes an upper swing body 3 that is rotatably mounted on a lower traveling body 2, a boom 4, an arm 5, a bucket 6, and a boom cylinder that operates the upper swing body 3. 7, a work attachment 10 including an arm cylinder 8 and a bucket cylinder 9 is mounted.

  The structure of the hydraulic cylinders 7 to 9 used in the attachment 10 is shown in the hydraulic cylinder 15 of FIG.

  The hydraulic cylinder 15 includes a cylindrical cylinder tube 16, a cylindrical cylinder head 11 provided at an opening end of the cylinder tube 16 via a tightening bolt 13, and reciprocation within the cylinder tube 16 and the cylinder head 11. The piston rod 20 is inserted as much as possible, and the rod side mounting portion 12 is provided at the end of the piston rod 20 on the cylinder extension side.

  The cylinder head 11 is attached to the opening end of the cylinder tube 16 by a plurality of fastening bolts 13.

  A dust seal 14 is attached to the opening edge on the inner peripheral side of the cylinder head 11.

  As shown in FIG. 3, the dust seal 14 is disposed at a position protruding from the cylinder head 11, and is provided with a reinforcing ring 21 made of metal or a strong resin that is not easily deformed, provided on the inner peripheral side of the cylinder head 11, The elastic seal body 30 is provided with a lip 33 integrally formed on the inner peripheral side of the reinforcing ring 21.

  The reinforcing ring 21 includes a cylindrical portion 22 mounted on the inner peripheral side of the cylinder head 11, a reduced diameter portion 23 that decreases in diameter from the cylinder extension side end of the cylindrical portion 22 toward the piston rod 20, and a reduced diameter portion 23. From the minimum diameter side, a protruding portion 24 protruding in the cylinder extending direction is provided beyond the lip portion 33.

  The snap ring 40 prevents the dust seal 14 from moving in the cylinder extending direction.

  The seal body 30 extends from the vicinity of the reduced diameter portion 23 toward the cylinder extending direction, and extends to the cylinder contraction direction from the vicinity of the reduced diameter portion 23 and the dust strip 31 slidably contacting the outer peripheral surface of the piston rod 20. The lip portion 33 includes a seal lip 32 that slidably contacts the outer peripheral surface of the piston rod 20.

  The dust lip 31 is provided to scrape off dust adhering to the outer peripheral surface of the piston rod 20 and prevent entry into the inside, and the seal lip 32 is provided to prevent oil from leaking to the outside.

  The lip portion 33 scrapes dust in accordance with the reciprocating motion of the piston rod 20 and discharges the scraped dust, and prevents the dust from entering the cylinder tube 16.

  Further, since a part of the lip portion 33 protrudes from the cylinder head 11, dust can be scraped and discharged more effectively than when the lip portion 33 is not protruded.

  Further, the projecting portion 24 is configured to cover the lip portion 33 from the outer peripheral side of the piston rod 20.

  According to the above embodiment, the following effects are obtained.

  By providing the protruding portion 24 so as to cover the lip portion 33 from the outer peripheral side of the piston rod 20, damage or deterioration due to contact of foreign matter such as earth and sand or plants with the lip portion 33 can be prevented.

  A dust seal cover is attached to a general dust seal as in Patent Document 1. However, in the first embodiment, since the projecting portion 24 plays the role of a dust seal cover, it is not necessary to attach the dust seal cover.

  Since the diameter of the dust seal 14 of the first embodiment is determined by the diameter of the piston rod 20, one dust seal can be configured to be attachable to a plurality of hydraulic cylinders having the same rod diameter. Compared with the case where a cover is attached, the number of parts can be reduced.

  By configuring the dust seal 14 to be compatible with the installation of the existing dust seal, it is possible to cope with the existing hydraulic cylinder by replacing the dust seal.

  Next, with reference to FIG. 4, the dust seal of Embodiment 2 of this invention is demonstrated.

  Since the second embodiment has substantially the same configuration as that of the first embodiment, differences will be described here.

  The difference between the second embodiment and the first embodiment is that an opening diameter-reduced portion 25 a that is diameter-reduced toward the piston rod 20 is provided at the opening end portion 25 of the protruding portion 24.

  The opening reduced diameter portion 25a is configured to cover the end portion of the lip portion 33 from the cylinder extending direction.

  Thus, by providing the opening reduced diameter portion 25a in addition to the protruding portion 24, the function of protecting the lip portion 33 can be enhanced.

  The opening diameter-reduced portion 25a is configured to extend substantially perpendicularly from the tip portion of the projecting portion 24 toward the outer peripheral surface of the piston rod 20, but may have a shape that approaches the piston rod 20 as the distance from the lip portion 33 increases. Good.

DESCRIPTION OF SYMBOLS 1 Work machine 2 Lower traveling body 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Attachment 11 Cylinder head 12 Rod side attachment part 13 Clamping bolt 14 Dust seal 15 Hydraulic cylinder 16 Cylinder tube 20 Piston Rod 21 Reinforcement ring 22 Cylindrical portion 23 Reduced diameter portion 24 Projection portion 25 Open end portion 25a Open diameter reduced portion 30 Seal body 31 Dustrip 32 Seal lip 33 Lip portion 40 Snap ring

Claims (2)

A hydraulic cylinder comprising: a cylinder tube; a cylinder head attached to an open end of the cylinder tube; and a piston rod penetrating the cylinder head and reciprocally inserted into the cylinder tube. A dust seal that scrapes off dust adhering to the outer peripheral surface of the rod,
The dust seal is composed of a reinforcing ring mounted on the inner peripheral side of the cylinder head and an elastic seal body integrally formed on the inner peripheral side of the reinforcing ring,
The seal body includes a lip portion that is in sliding contact with the outer peripheral surface of the piston rod, and a part of the seal body projects from the cylinder head in the cylinder extending direction.
The reinforcing ring includes a cylindrical portion that is mounted on the inner peripheral side of the cylinder head, a reduced diameter portion that decreases in diameter from the cylinder extension side end portion side of the cylindrical portion toward the piston rod, and the reduced diameter portion. A dust seal comprising a protruding portion protruding in the cylinder extending direction beyond the lip portion from the minimum diameter side. 2. The dust seal according to claim 1, further comprising an opening diameter-reduced portion that is reduced in diameter toward an outer peripheral surface of the piston rod at an opening end portion of the projecting portion.

Images