JPH0719538Y2 - Full flow filter - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a full flow filter used in a hydraulic working machine such as a hydraulic excavator.

B. Prior Art This type of full-flow filter is installed in a tank or inserted in a pipeline as shown in FIGS. 6 and 7.
In FIGS. 6 and 7, the oil in the tank 1 is guided from the hydraulic pump 3 through the suction filter 2 to the actuator 5 through the control valve 4. The oil that has driven the actuator 5 is filtered by the filter 6 and flows into the tank 1.

FIG. 8 shows a conventional example in which the full flow filter 6 is installed in the tank 1. A filter case 61 is integrally provided in the tank body 1a, and a filter element 62 is detachably provided therein. An oil inlet pipe 63 is attached to the filter case 61, and the oil that has flowed into the filter case 61 from here is filtered by the filter element 62 and flows out from the lower outlet 64 of the filter case 61 into the tank body 1a. 1b is a suction filter, and the oil in the tank 1 is guided to a hydraulic pump (not shown) through the filter 1b. Reference numeral 65 is a filter cover, which is removed from the tank body 1a when replacing the filter element 62. A relief valve 67 is fixedly held by a spring 66 between the cover 65 and the upper end surface of the filter element 62, and is opened when the external pressure of the filter element 62 becomes larger than a predetermined value with respect to the internal pressure thereof.
Oil that flows into the filter case 61 is filtered by the filter element 62.
It directly flows out from the lower outlet 64 to the tank body 1a without being filtered.

When such a full flow filter 6 is clogged, the pressure loss in the circuit becomes large. Therefore, a differential pressure type indicator switch for detecting the clogging is built into the full flow filter and an alarm is issued by the operation signal of the switch. As conventionally known, an indicator switch is incorporated in the filter 6 as needed. by the way,
A work machine such as a hydraulic excavator is used for various works by mounting various front attachments, but it is usually used as an excavation work machine, and a clogging alarm is not particularly required. However, when an attachment such as a hydraulic breaker that is used in a place where the work environment related to oil pollution is bad is attached, it is essential to attach an indicator switch to detect clogging of the filter. However, the mounting of this indicator switch is not standard equipment because it causes a cost increase, and it is specially mounted on a working machine using a front attachment such as a hydraulic breaker.

C. Problems to be solved by the device However, it is very difficult to install the indicator switch after shipping from the factory, and it is also efficient to install the filter with the built-in indicator switch only on a specific machine at the time of factory shipping. There are difficulties.

A technical problem of the present invention is to make it possible to easily attach an indicator switch to a specific machine in a factory even after being used once.

D. Means for Solving the Problems The present invention will be described with reference to FIG. 1 and FIG. 2 showing an embodiment. The present invention has a filter element insertion hole in the upper portion and an oil inlet is a side surface. A filter case 15 having an outlet provided on the lower surface thereof, a filter element 12 for filtration mounted on the lower surface of the filter case 15 so that the oil after filtration flows through the outlet, and the filter element insertion hole. Is attached to the upper part of the filter element 12 in a removable manner, and when the pressure difference between the inside and outside of the filter element 12 exceeds a predetermined value, the operation causes the oil to escape from the outlet without filtering. The first relief valve 67 is applied to the full flow filter.

And the above-mentioned technical problem is that the portion of the filter element 12 from which the first relief valve 67 is removed is provided with a projecting conduit 115 projecting upward to guide the internal pressure of the filter element 12 to the outside. The second cover 13 having the indicator switch 21 for detecting the pressure difference between the inside and the outside of the filter element 12 is attached to the portion of the filter case 15 to which the second relief valve 11 is attached and the first cover 65 is removed. By fitting the outer peripheral portion of the protruding conduit 115 to the second cover 13 in an oil-tight manner, the external pressure of the filter element 12 is applied to the external pressure detection portion 216 of the indicator switch 21, and the filter element 12 This is solved by guiding the internal pressure of the above into the second cover 13 and causing it to act on the internal pressure detecting portion 211a (FIG. 2) of the indicator switch 21.

E. Function Normal full flow filter has indicator switch 21
It has the 1st cover 65 which does not have and the 1st relief valve 67 which does not have the projecting pipeline 115. Its the first cover
If the 65 and the first relief valve 67 are replaced with the second cover 13 and the second relief valve 11, the indicator can be easily incorporated into a full flow filter.

That is, by attaching the second cover 13 to the filter case 15 so that the outer peripheral portion of the projecting conduit 115 of the second relief valve 11 is oil-tightly fitted to the second cover 13, the indicator switch 21 The inner pressure detecting portion 211a is acted upon by the element inner pressure and the outer pressure detecting portion is acted upon by the element outer pressure, and the switch 21 is operated when the pressure difference between the inner and outer portions exceeds a predetermined value. A clogging alarm can be issued by the operation signal of the switch 21.

It should be noted that, in the above D and E for explaining the configuration of the present invention, the drawings of the embodiments are used to make the present invention easy to understand, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment of the full flow filter according to the present invention will be described with reference to FIGS. In the figure, the same parts as those in FIGS. 6 to 8 are designated by the same reference numerals.

FIG. 1 is a longitudinal sectional view of a main part of a full flow filter according to the present invention.

The full flow filter 10 includes a filter case 15 that is integral with the tank body 1a. 11 is a relief valve,
It is installed on the upper surface of the filter element 12 as in the past.
It is fixedly held by a spring 14 between the filter cover 13. The relief valve 11 has a valve body 111 and a movable valve portion 113 which is always closed by a spring 112 and opens against the spring force when the pressure difference between the filter element external pressure PO and the internal pressure PI becomes a predetermined value or more. The valve body 111 is provided with a passage 114 for guiding the internal pressure of the filter element to the outside of the filter element 12 and a protruding pipe passage 115 continuous with the passage 114.

Filter cover 13 that is detachably screwed to the tank body 1a
An indicator switch 21 for detecting clogging of the filter element 12 from the pressure difference between the inside and the outside thereof is provided therein, and an internal pressure passage 131 into which the projecting pipe line 115 is fitted to guide the element internal pressure is formed. FIG. 4 is a top view of the filter cover 13, where 13a is an indicator switch mounting hole, 13b is a thermoswitch mounting hole, 13c is a wiring hole, 13d is a cover mounting bolt hole, and 13e is an air vent hole.

FIG. 2 shows the details of the indicator switch 21. The side wall of the indicator switch main body 211 is provided with a hole 211a as an internal pressure detecting portion for guiding the internal pressure of the filter element, and inside the indicator switch main body 211 is a movable valve body 213 which is constantly urged downward by a spring 212. It is slidably installed inside. A movable electrode 214 electrically connected to the main body 211 is projectingly provided on an upper part of the movable valve body 213, and a fixed electrode 215 electrically separated from and brought into contact with the movable electrode 214 is provided on an upper part of the main body 211. Has been.

Further, in FIG. 1, the inner pressure passage 131 of the cover 13 communicates with the inner pressure detecting hole 211a of the indicator switch 21, and the outer pressure detecting portion 216 of the indicator switch 21 has a surface inside the filter case 15 on which the filter element outer pressure acts. is doing. The fixed electrode 215 is connected to the clogging alarm lamp via the thermoswitch 33. That is, as shown in FIG. 3 which is an electric circuit diagram of the clogging alarm device, the battery 31
The alarm lamp 32, the thermoswitch 33, and the indicator switch 21 are connected in series to form an alarm circuit.

When the clogging alarm device is not used with such a full flow filter, the filter cover 65 and the relief valve 66 shown in FIG. 8 may be used. When a clogging alarm device is needed, the indicator switch 21 for the clogging alarm device can be easily added simply by replacing the filter cover 65 and the relief valve 66 with those shown in FIG.

In the full-flow filter shown in FIG. 1, when the pressure difference between the inside and outside of the filter element exceeds the value set by the spring 112, the relief valve 11 opens and the oil that has flowed into the filter case 15 passes through the inside of the filter element 12 to the lower part. Undesired increase in the pipeline pressure caused by flowing out from the outlet to the tank body 1a is suppressed.

On the other hand, the filter element internal pressure PI is generated by the passage 114 and the projecting pipeline 11.
It reaches the internal passage 131 through 5 and acts on the upper end surface of the movable valve body 213 from the internal pressure detecting hole 211a. Since the filter element external pressure PO acts on the lower end surface of the movable valve body 213, when the pressure difference inside and outside the filter element exceeds the value set by the spring 212, the movable valve body 213 moves upward and the movable electrode 214 is fixed. The electrode 215 is touched and the indicator switch 21 is closed. At this time, if the oil temperature is equal to or higher than the predetermined value, the thermo switch 33 is closed, so the circuit of FIG. 3 is closed and the alarm lamp 32 is turned on. Thereby, the operator can appropriately know the replacement time of the filter element 12.

The present invention can also be applied to a line-type full flow filter installed in the middle of a pipeline without installing the full flow filter in the tank. Fig. 5 shows an example, 51 is a filter case, 52 is an inlet port, 53 is an outlet port,
Others are the same as those of the full flow filter of FIG. 1, and therefore, the same reference numerals are given and the description thereof will be omitted.

G. Effect of the Invention According to the present invention, an indicator switch for an alarm device for clogging an existing full-flow filter by simply replacing the first cover and the first relief valve with the second cover and the second relief valve. Can be attached.

[Brief description of drawings]

1 to 4 illustrate one embodiment of the present invention.
FIG. 1 is a cross-sectional view of the main parts of the relief valve and the filter cover,
2 is a half sectional view of the indicator switch, FIG. 3 is a circuit diagram of the clogging alarm device, and FIG. 4 is a top view of the filter cover. FIG. 5 is a vertical sectional view showing an example in which the present invention is applied to a line type full flow filter. 6 and 7 are hydraulic circuit diagrams, and FIG. 8 is a diagram showing a conventional full flow filter installed in a tank. 11: Relief valve, 12: Filter element 13: Filter cover, 14: Spring 15: Filter case, 21: Indicator switch 24: Thermo switch, 114: Passage 115: Projection line, 131: Internal passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI technical display location F15B 21/04 D 7618-3H (72) Creator Toshiyuki Tagami 2396 Arima, Miyazaki-ku, Kawasaki-shi, Kanagawa Kaiko Sangyo Co., Ltd. Arima Factory (56) References Japanese Patent Publication Sho 41-9741 (JP, B1)

Claims (1)

[Scope of utility model registration request] 1. A filter element insertion hole is provided in an upper portion,
A filter case having an oil inlet provided on a side surface and an outlet provided on a lower surface, a filter element for filtration mounted on a lower surface in the filter case so as to flow the filtered oil to the outlet, and the filter element A first cover for closing the insertion hole; and a first detachably attached to the upper portion of the filter element for allowing the oil to escape from the outlet without filtering when the pressure difference between the inside and the outside of the filter element exceeds a predetermined value. In a full-flow filter having a first relief valve, a portion of the filter element from which the first relief valve is removed is provided with a projecting pipe line protruding upward to guide the internal pressure of the filter element to the outside. The second relief valve is attached to the filter case, and the filter case is removed from the filter case where the first cover is removed. A second cover having an indicator switch for detecting a pressure difference between the inside and the outside of the inlet, and fitting the outer peripheral portion of the projecting pipe line to the second cover in an oil-tight manner to thereby detect the external pressure of the indicator switch. A full-flow filter, wherein the external pressure of the filter element is applied to the internal pressure detection portion of the indicator switch by guiding the internal pressure of the filter element into the second cover.