JPH0220535Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention is applicable to hydraulic, pneumatic, or electric cylinder devices, shock absorbers, etc., when used in environments where dust, moisture, etc. are scattered. This invention relates to a piston rod protection device that protects a seal between a piston rod and a rod cover by covering it with a bellows.

``Prior Art'' Hitherto, as this type of piston rod protection device, those shown in FIGS. 3 and 4 have been known. This device connects a proximal end 1a of a cylindrical bellows 1 with a tightening band 2.
The bellows 1 is directly tightened and fixed to the outer peripheral surface of the rod cover 4 of the cylinder body 2, while the tip 1b of the bellows 1 is
The piston rod 6 is also tightened by the tightening band 5.
The bellows 1 covers the piston rod 6 and the sealing portion between it and the rod cover 4 by directly tightening and fixing it to the outer peripheral surface of the bellows 1. A plurality of air vent holes 7 are bored in the peripheral wall of the bellows 1 in order to open the inside to the atmosphere, and a mesh 8 serving as a filter is stretched over the air vent holes 7.

``Problem that the invention attempts to solve'' However, with this, if the overall length of the bellows 1 is short, the air vent hole 7 will be blocked when it contracts.
When piston rod 6 is operated at high speed, bellows 1
When it expands, negative pressure is created inside it, causing problems such as irregular deformation and damage. Furthermore, since the mesh 8 is stretched over the air vent hole 7 of the bellows 1, manufacturing thereof is troublesome and costs are high. Further, the base end 1a of the bellows 1 is connected to the outer diameter of the rod cover 4, and the tip end 1b is connected to the piston rod 6.
The diameters of the proximal end 1a and the distal end 1b must be made to be different depending on the outer diameter of the bellows 1, which complicates the manufacturing of the bellows 1 itself, and also poses the problem of having to decide the mounting direction. It was hot.

The present invention aims to easily solve these problems.

``Means for Solving the Problems'' The piston rod protection device of the present invention has a protruding base end 10a and a distal end 10b having the same diameter, as in the embodiment shown in FIGS. 1 and 2, for example. A bellows 10, an annular spacer 14 made of synthetic resin or sintered metal that has air permeability due to foam gaps or gaps between particles, and has a split 14a in a part of the circumference;
A pair of tightening bands 13 and 16 of the same size are provided. The spacer 14 has an inner diameter corresponding to the inner diameter of the piston rod 15 and an outer diameter corresponding to the outer diameter of the boss portion 12a of the rod cover 12. Then, the base end 10a of the bellows 10 is
It is fitted onto the outer periphery of the boss portion 12a of the rod cover 12 and tightened from the outside with the tightening band 10a, and
A spacer 14 is fitted around the outer periphery of the piston rod 15, and the tip 10b of the bellows 10 is fitted onto the outer periphery of the spacer 14, and the tip 10b and the spacer 14 are tightened with a tightening band 16.

"Function" Therefore, as the rod cover 15 expands and contracts, the bellows 1
When the bellows 10 expands and contracts, air is taken in and exhausted from the inside of the bellows 10 through the spacer 14 made of a breathable material. The inner diameter of the spacer 14 corresponds to the inner diameter of the piston rod 15, and the outer diameter corresponds to the outer diameter of the boss portion 12a of the rod cover 12.
Since the protruding proximal end 10a and distal end 10b of the bellows 10 have the same diameter, the bellows 10 can be used without any problem even if the proximal end and distal end are turned upside down, and the tightening band can also be used on the proximal end. The same thing can be used for the tip side.

"Embodiment" An embodiment of the present invention will be described below in detail based on the drawings.

In FIG. 1, a bellows 10 is integrally molded into a cylindrical shape without forming an air vent hole in the peripheral wall as in the conventional case, and has a base end 10a and a distal end 1 having the same diameter.
0b are provided protruding from both ends. Its base end 10a
is directly tightened and fixed to the outer peripheral surface of the boss portion 12a of the rod cover 12 of the cylinder body 11 by a tightening band 13, whereas the tip portion 1 of the bellows 10
0b is indirectly tightened and fixed to the outer peripheral surface of the piston rod 15 via an annular spacer 14 with a tightening band 16 having the same size as the tightening band 13 described above.

The spacer 14 is made of breathable synthetic resin or sintered metal, and its inner diameter is the same as that of the piston rod 15.
The outer diameter corresponds to the outer diameter of the boss portion 12a, and as shown in FIG. 2, a split 14a is formed in a part of the circumference. The air permeability of the spacer 14 is ensured by forming gaps such as foam gaps or gaps between particles. After the spacer 14 is removably fitted to the piston rod 15, it is tightened to the piston rod 15 together with the tip 10b of the bellows 10 by the tightening band 16, and the spacer 14 is compressed to close its split 14a. In addition, as this spacer 14, two semicircular segments are attached to the piston rod 15.
It may be fitted along the outer periphery of the

Therefore, when the bellows 10 expands and contracts as the piston rod 15 expands and contracts, the inside of the bellows 10 is exhausted and sucked in through the air-permeable spacer 14, so the overall length of the bellows 10 is short, so that it can be folded up as it contracts. After they overlap, even if they are expanded at high speed, the internal pressure will not become negative.

In addition, in the above embodiment, the tip portion 10 of the bellows 10
b was fixed to the piston rod 15 via the spacer 14, and the base end 14a of the spacer 14 was fixed directly to the outer peripheral surface of the rod cover 12.
The proximal end 10a of the bellows 10 may be similarly fixed to the outer peripheral surface of the rod cover 12 via a breathable spacer, and the proximal end 10a and the distal end 10 of the bellows 10 may be
Both of b may be indirectly fixed via a spacer. Furthermore, the present invention is applicable not only to hydraulic, pneumatic, and electric cylinder devices, but also to cylinder-structured shock absorbers.

"Effects of the Invention" As described above, the piston rod protection device of the present invention has the following effects.

As the inside of the bellows is expanded and contracted, air can be exhausted and taken in through the breathable spacer, so the manufacturing cost is lower than the conventional structure in which a mesh is stretched over the air vent hole of the bellows.

The overall length of the bellows is short, and even if the bellows are folded and overlapped as they contract and then expand at high speed, there is no negative pressure inside the bellows, which causes the bellows to deform irregularly as in the case of conventional bellows. There is no such thing, and its durability is good.

Since air is exhausted and taken in through the breathable spacer, the dustproof effect is good and the durability of the gasket that seals between the piston rod and the rod cover can be improved.

Since the spacer is made of a material that has air permeability due to the foamed gaps or the gaps between particles, it is possible to accurately prevent the infiltration of dust, moisture, and the like.

Since the spacer is provided with a split, it can be easily attached to and removed from the piston rod, and can be tightly held on the piston rod precisely at the same time as the tip of the bellows.

The inner diameter of the spacer corresponds to the inner diameter of the piston rod, and the outer diameter corresponds to the outer diameter of the boss of the rod cover, and the protruding base end and tip of the bellows have the same diameter. In addition, both the front and rear sides of the bellows can be made exactly the same, and even if the base end and the tip end are turned upside down, the bellows can be used without any problem.

The same tightening band can be used on the proximal and distal sides.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention, Figure 1 is a sectional view of the main part, Figure 2 is a perspective view of a spacer, and Figures 3 and 4 are a sectional view of a conventional example and an enlarged view of its bellows. FIG. 10... Bellows, 10a, 10b... Base end and tip end of bellows, 11... Cylinder body, 12...
Rod cover, 12a... Boss portion of rod cover, 13, 16... Tightening band, 14... Spacer, 14a... Spacer split, 15... Piston rod.

Claims (1)

[Scope of utility model registration request] A bellows 10 whose protruding proximal end 10a and distal end 10b have the same diameter, and a ring-shaped bellows 10 made of synthetic resin or sintered metal that has air permeability due to foam gaps or gaps between particles and has a split 14a in a part of the circumference. spacer 14 and a pair of tightening bands 13, 1 of the same size.
6, the spacer 14 has an inner diameter corresponding to the inner diameter of the piston rod 15, an outer diameter corresponding to the outer diameter of the boss portion 12a of the rod cover 12, and a base end portion 10a of the bellows 10. is fitted onto the outer periphery of the boss portion 12a of the rod cover 12 and tightened from the outside with the tightening band 10a, and the spacer 14 is fitted onto the outer periphery of the piston rod 15,
Furthermore, the piston rod protection device is characterized in that the tip 10b of the bellows 10 is fitted around the outer periphery of the spacer 14, and the tip 10b and the spacer 14 are tightened with a tightening band 16.