JP2568166Y2 - Filter element - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter element used for a return oil system (return system) of a hydraulic circuit.

[0002]

2. Description of the Related Art Filters are installed to reduce and remove dust in hydraulic fluid. For example, various filters according to the purpose are installed at various places in a hydraulic shovel and the like.

[0003] Among them, a filter used in a return oil system (return system) through which all return oil passes in a hydraulic circuit such as a hydraulic excavator, as shown in FIG. 2 , a hydraulic oil connected to the return oil system. In the case of a hydraulic shovel, an inlet 11 is provided on the outer peripheral surface and a hydraulic oil outlet 12 communicating with the hydraulic oil tank is provided inside the filter case 13 provided on the bottom plate portion or directly inside the hydraulic oil tank. Nominally in general
A standard filter element (filter paper) 14 having a filter particle size of 10μ throughout is mounted.

A relief valve 17 which opens from a valve seat 16 against an operating pressure setting spring 15 when the filter element is clogged or an instantaneous pressure is generated is provided at an upper opening edge of the filter element 14. A strainer 18 for catching debris when the relief valve 17 is opened is held by a pressing spring 20 between the strainer 18 and the element detachable lid 19.

[0005]

As described above, the conventional filter element 14 is composed of one kind of filter paper having a uniform filtration particle size of about 10 μ throughout. It is impossible to capture small dust, and there is a limit to improving the cleanliness of hydraulic oil.

On the other hand, the use of a filter element made of filter paper having a higher filtration particle size throughout can improve the cleanliness of hydraulic oil.
The passage resistance (pressure loss) in the filter element also increases, and the filter element is not suitable as a filter element used for a return oil system (return system) in a hydraulic circuit.

The present invention has been made in view of such a point, and a hydraulic circuit return oil system capable of dramatically improving the cleanliness of hydraulic oil without significantly increasing passage resistance (pressure loss). It is intended to provide a filter element.

[0008]

According to a first aspect of the present invention, there is provided a filter element used in a return oil system of a hydraulic circuit, wherein a first element 32 formed in a tubular shape and an outer periphery of the first element 32 are provided. Ru filter element der of double structure consisting of the second element 33 having a first element 32 finer filter particle size is provided in a part of the surface.

[0009]

According to the first aspect of the present invention , most of the hydraulic oil is the first oil .
Passing resistance (pressure loss) because only element 32 is passed
Does not rise so much, and part of the hydraulic oil is the first element
32 than through the double structure of the second element 33 having a fine filter particle size in the process again and again circulated, cleanliness of the hydraulic oil dramatically improved.

[0010]

EXAMPLES The following describes the present invention with reference to the embodiment illustrated in Figure 1.

FIG. 1 shows a filter element 31 having a double structure according to the present invention. For example, a standard first element (filter paper) 32 having a standard filtration particle size of about 10 μm is formed in a cylindrical shape . the lower part of the outer peripheral surface of the first element 32, for example, about 3μ cylindrical dense with fine filter particle size
The second element (filter paper) 33 is closely fitted detachably,
Alternatively, they are integrally fixed by bonding. In the case of adhesive fixing,
Partial adhesion is used in consideration of hydraulic oil permeability.

In this filter element 31, most of the hydraulic oil passes only through the first element 32, so that the passage resistance (pressure loss) does not increase so much and some of the hydraulic oil
In the course of many times is circulated through the double structure of the second element 33 having a fine filter particle size than the first element 32, the
Fine dust that cannot be captured and removed with only one element 32
It is gradually capturing and removing the second element 33, the cleanliness of the hydraulic fluid you dramatically improved compared to the filter element 14 only conventional standard elements.

[0013] The filter element 31 that is shown in FIG. 1
Is the interior of the filter casing 13 of the return oil system (return system) shown in FIG. 2, or the inside of the hydraulic oil tank may be attached by direct internal method.

[0014]

According to the first aspect of the present invention, a cylindrical shape is provided.
Since the second element having a finer filtering granularity than the first element is provided in a double structure on a part of the outer peripheral surface of the formed first element, in the return oil system of the hydraulic circuit, the entire filter element has a passage resistance ( the pressure loss) rises slightly, while substantially maintaining the conventional passage resistance, hydraulic oil
Part of the second element has a finer filtration particle size than the first element.
The process of repeated circulation through the double structure of the element
Therefore, fine particles that cannot be captured and removed with only the first element
Body and can gradually capture and removal by the second element, the cleanliness of the hydraulic oil in the double structure part can be dramatically improved, Ru can improve durability and reliability of the hydraulic equipment.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a filter element according to the present invention corresponding to claim 1;

FIG. 2 is a hydraulic circuit equipped with a conventional filter element .
It is sectional drawing of a return oil type filter.

[Explanation of symbols]

32 1st element 33 2nd element

Claims (1)

(57) [Scope of request for utility model registration] 1. A hydraulic circuit filter elements used in the return oil system, a first element formed in a tubular shape, fine filter particle size than the first element is provided on a part of the outer peripheral surface of the first element And a second element having the following .