JPS6349580Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a pneumatic circuit for a hydraulic machine, and particularly to a pneumatic circuit suitable for a circuit that consumes relatively little air.

[Background of the idea]

FIG. 3 is a circuit diagram showing an overview of a pneumatic circuit of a conventional hydraulic machine, and FIGS. FIG. 4a is a cross-sectional view showing the on-loading state, and FIG. 4b is a cross-sectional view showing the unloading state.

In FIG. 3, 1 is a reciprocating air compressor, and as shown in FIG. a valve 13, an unload valve 14 that is pushed down by an andload signal, and an air supply valve that is opened by negative pressure in the cylinder during the air supply process and is pushed open by the unload valve 14 during unloading. A valve 15 is installed.

In FIG. 3, 2 is a wet tank that cools the high-temperature, high-pressure compressed air produced by the air compressor 1, collects condensed water at the bottom, and sends dry air downstream. 3 is a connection between the air compressor 1 and the wet tank 2.
and a governor which opens a valve and outputs an unload signal to the air compressor 1 when the circuit pressure rises above a predetermined pressure. 5 is a dry tank which stores compressed air sent from the wet tank 2 and is connected to the wet tank 2 via a check valve 4. 6 is a safety valve connected to the dry tank 5, 7 is a filter which filters impurities during the compressed air discharged from the dry tank 5, 8 is a pressure reducing valve connected to the filter 7, 9 is a hydraulic oil tank connected to the pressure reducing valve 8, and 10 is a safety valve for the hydraulic oil tank 9. In addition, 11 is an air pressure pump which discharges grease for lubrication, and 12 is an accumulator which backs up the pilot hydraulic pressure, and these are also connected to the dry tank 5.

In the pneumatic circuit as described above, after the lubricating oil lubricates between the cylinder and piston of the air compressor 1, a portion of the lubricating oil adheres to the discharge valve 13 and lubricates the discharge valve 13. Most of it becomes dewy and is discharged together with compressed air. Also air compressor 1
In the high temperature, high pressure compressed air produced by the lubricating oil is oxidized, resulting in the formation of carbon. Furthermore, when the compressed air produced in this manner is cooled, moisture in the compressed air condenses to become water, which mixes with lubricating oil to form highly viscous drain. Such carbon and drain may block the flow path in the pneumatic discharge system including pneumatic equipment such as the air pump 11 and the accumulator 12, cause malfunction or damage, and cause contamination of the hydraulic oil in the hydraulic oil tank 9. .

For this reason, in the conventional pneumatic circuit shown in FIG. 3, for example, a manual drain valve is provided in the wet tank 2, and drain containing carbon is removed by opening this drain valve. That's what I do. Therefore, in this conventional pneumatic circuit, it is necessary to work close to the wet tank 2 when draining the drain, and the drain valve must be opened and closed manually. Drainage work becomes troublesome, and there is a risk that the drain containing carbon may adhere to the operator, making him or her more likely to be contaminated.

Furthermore, in the pneumatic circuit shown in FIG. 3, almost no compressed air is consumed after the hydraulic oil tank 9 is pressurized, and therefore the air compressor 1 is mostly in an unloaded state. It is driven by During this unloading, as shown by the arrow 3a in FIG. 4a, the air supply valve 15 remains open due to the signal from the governor 3 shown in FIG. The intake and exit are repeated via the air supply valve 15 due to the movement of the air. In such a case, the amount of oil carried away from the air compressor 1 along with the air is larger than when on-road, and this oil adheres to the portion of the air supply valve 15 where the passage is constricted. Then, due to unloading for a long time, the air supply valve 15
The amount of oil deposited on the pump increases, and this oil is pressurized together with the supply air and discharged into the discharge system within a short on-load time. Moreover, in such a state, the amount of carbon produced increases.

Therefore, in order to avoid such a situation where the amount of carbon generated increases, it is necessary to open the wet tank 2 to the outside as appropriate in consideration of releasing the unloading, but in the case of a conventional pneumatic circuit, Due to the trouble of having to open the drain valve manually as described above, this drain valve opening operation is difficult to carry out, and as a result, the pneumatic equipment constituting the air discharge system connected to the wet tank 2 and Carbon tends to cause malfunction, damage, and stains in various hydraulic equipment.

[Purpose of invention]

The present invention has been developed in view of the actual situation in the prior art, and its purpose is to be able to discharge drain containing carbon from a tank without providing a manual drain valve, and to make it possible to drain air from the tank without installing a manual drain valve. To provide a pneumatic circuit for a hydraulic machine that can easily suppress the amount of oil adhering to a valve part.

[Summary of the idea]

To achieve this objective, the present invention includes an air compressor, a tank that stores the compressed air discharged from the air compressor, and a governor that is disposed in a flow path that communicates the tank and the air compressor. The tank is equipped with a drain discharge means capable of discharging the drain in the tank in response to an electric signal, and a switch for operating the drain discharge means.

[Example of idea]

Hereinafter, the pneumatic circuit of the hydraulic machine of the present invention will be explained based on the drawings. FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG. 2 is a circuit diagram showing another embodiment of the present invention. In these figures, parts equivalent to those shown in FIG. 3 described above are designated by the same reference numerals.

In FIG. 1, reference numeral 16 denotes a drain valve connected to the wet tank 2, which discharges the drain in the wet tank 2 in response to air pressure. Reference numeral 17 designates a solenoid valve connected to the drain valve 16, which is switched by a switch 18, and is connected to the dry tank 5 via a filter 7a. Note that the switch 18 is disposed in the operating section of the hydraulic machine equipped with this embodiment, for example, in the driver's cab if the hydraulic machine is a construction machine. Also,
A filter 7b is also interposed in the flow path connecting the wet tank 2 and the governor 3. The above-mentioned drain valve 16 and electromagnetic valve 17 constitute a drain discharge means capable of discharging the drain from the wet tank 2 in response to an electric signal.

In this embodiment, the switch 18 must be operated when drain discharge work is performed after the air compressor 1 is driven to produce compressed air and this compressed air is supplied to a predetermined air discharge system. As a result, the solenoid valve 17 is switched from the position A shown in FIG. 1 to the position B, and the dry tank 5,
Compressed air from the air discharge system is guided to the drain valve 16 via the filter 7a and the electromagnetic valve 17, which opens the drain valve 16 and drains the drain containing carbon from the wet tank 2 to the outside. At this time, the pressure inside the wet tank 2 decreases, causing the governor 3 to close, thereby canceling the unload signal, and the air supply valve 1 shown in FIG.
5 is closed, resulting in the state shown in FIG. 4a.

In one embodiment configured in this way,
The drain containing carbon in the wet tank 2 can be discharged only by operating the switch 18. Therefore, this work can be carried out extremely easily, and
Since there is no need to get close to the drain, there is no need for workers to be contaminated by the drain.

Furthermore, by operating the switch 18 as necessary, the air supply valve 15 can be closed as shown in FIG. 4a, thereby reducing the amount of oil that adheres to the air supply valve. It can be easily suppressed, the amount of carbon contained in compressed air can be reduced, and malfunctions and damage to pneumatic equipment and various hydraulic machines that constitute the air discharge system can be prevented.

Further, in another embodiment shown in FIG. 2, a solenoid valve 19 is provided as a drain discharge means capable of discharging the condensate in the wet tank 2 in response to an electric signal, and this solenoid valve 19 is connected to the wet tank 2. , a solenoid valve 19 can be switched by operating a switch 18.

Even in this embodiment, when draining the drain from the wet tank 2, it is only necessary to operate the switch 18, whereby the solenoid valve 19 is switched from position C to position D in FIG. The drain containing carbon inside is connected to this solenoid valve 19.
is discharged to the outside through the

Even in the embodiment configured in this way, the same effects as the embodiment shown in FIG. 1 described above can be achieved.

Note that the switch 18 described above may be activated by manual operation, or may be connected to a counter or the like and activated automatically without human intervention after a predetermined period of time has elapsed.

[Effect of idea]

As described above, the pneumatic circuit of the hydraulic machine of the present invention includes a drain discharge means consisting of a pneumatically operated drain valve and a solenoid valve, or only a solenoid valve, and a switch for operating this drain discharge means. Since the structure is equipped with a manual drain valve, it is possible to drain the drain containing carbon from the tank without installing a manual drain valve.
Compared to the conventional method, drain discharge work is easier, and there is an effect that contamination of the operator by the drain can be prevented. In addition, by simply operating a switch, the amount of oil adhering to the air supply valve can be easily suppressed, reducing the amount of carbon contained in compressed air. It can prevent damage and stains caused by poor work.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the pneumatic circuit of a hydraulic machine of the present invention, Fig. 2 is a circuit diagram showing another embodiment of the present invention, and Fig. 3 is an outline of the pneumatic circuit of a conventional hydraulic machine. FIGS. 4a and 4b are detailed views of the main parts of the air compressor provided in the pneumatic circuit shown in FIG. 3, and FIG. 4a is a sectional view showing the on-road state. FIG. 4b is a sectional view showing the state at the time of unloading. 1... Reciprocating air compressor, 2... Wet tank, 3... Governor, 5... Dry tank, 7a,
7b... Filter, 15... Air supply valve, 16... Drain valve, 17, 19... Solenoid valve, 18... Switch.

Claims (1)

[Scope of utility model registration request] In a pneumatic circuit of a hydraulic machine including an air compressor, a tank storing compressed air discharged from the air compressor, and a governor disposed in a flow path communicating the tank and the air compressor. A pneumatic circuit for a hydraulic machine, comprising: a drain discharge means capable of discharging the drain in the tank in response to an electric signal; and a switch for operating the drain discharge means.