JPH0434248Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to an air venting device for a hydraulic fluid pipe that supplies oil to a hydraulically operating part.

(Prior Art) In general-purpose vehicles such as agricultural tractors, the oil reservoir for working oil is shared with the transmission case. Therefore, the air stirred by the transmission gear and drawn into the oil is sent to the high pressure circuit for the hydraulic oil. These bubbles grow inside the oil filter and act on the oil in the high-pressure circuit, causing a combustion phenomenon that generates abnormal noise and deteriorates the oil.

(Problem that the invention seeks to solve) As a countermeasure to this problem, it is possible to install an air reservoir in the hydraulic circuit to separate and release the air in the oil, but air venting is inappropriate on the high pressure side, and Since the pump must be installed in the tank, air is sucked in when the pump is normally opened to the atmosphere, and when the pressure pump is stopped, the oil level in the pipe line is lowered to the oil level in the transmission case. Furthermore, it is difficult to vent air during operation.

(Means for Solving the Problems) This invention solves the above problems and performs the air removal automatically and while the hydraulic oil circuit is operating.

That is, an air reservoir is provided in the casing of an oil filter provided in a conduit between the oil reservoir and the working hydraulic pump, and the air reservoir is communicated with the surface of the oil in the oil reservoir through a return pipe with a return pump interposed therebetween. A reed switch operated by a float is provided at the position of the lowest allowable oil level in the air reservoir, and the return pump is operated by the operation of this reed switch.

(Function) Hydraulic oil is sent from the oil reservoir to the high-pressure hydraulic operating part via the oil filter by the pressure pump, but the flow velocity decreases within the oil filter and air is separated when passing through the filter element. When air accumulates in the air reservoir and the oil level drops to the lowest allowable oil level, the reed switch is activated by the action of the float and the return pump is activated. The air in the air reservoir is sent below the oil surface of the oil reservoir through the return pipe and escapes into the atmosphere as bubbles. Also, oil that gets mixed into the return pipe due to disturbance of the oil level stays in the oil sump. When the air reservoir oil level rises, the return pump is stopped by an appropriate automatic operation stop means. In this case, the tip of the return pipe is submerged in the oil in the oil sump, so air is not sucked in.

(Example) This invention will be explained using an example. Figure 2 shows an example of a hydraulic oil pipe. The hydraulic oil pipe 1 is constructed by connecting a transmission case 2 which also serves as a reservoir for hydraulic oil, an oil filter 3, a pressure pump 4, and a hydraulic actuator 5 through an oil feed pipe 6. As shown in FIG. 1, an air reservoir 8 is provided protruding from the casing 7 of the oil filter 3, and a filter element 9 is provided inside the casing. The filter element 9 is inclined at about 5° to 10° to improve the separation of air in the oil. A float 10 with a magnet 10a attached surrounding a hollow column 8a suspended in an air reservoir 8
A reed switch 11 is provided inside the hollow column 8a so as to be able to rise and fall freely, and a reed switch 11 is located at the lower allowable minimum oil level.
A reed switch 12 is provided at an appropriate position above. The air reservoir 8 and the mission case 2 are connected by a return pipe 14 with a return pump 13 interposed in between, and one pipe end 14a of the return pipe 14 is connected to the mission case 2.
position below the oil level. The return pump 13 has a drive circuit which is started by actuation of the reed switch 11 and stopped by actuation of the reed switch 12. As means for stopping the automatic operation of the return pump 13, in addition to the reed switch 12, the reed switch 1 is also used.
A timer may be used to open the return pump drive circuit at an appropriate time after the operation of step 1.

(Effects of the invention) Since the air venting device for the hydraulic oil pipe of this invention has the above-described structure, it operates automatically and continuously to discharge air even during operation of the hydraulic actuating section. Therefore, it is possible to prevent the generation of abnormal noise and the deterioration of the oil due to the combustion phenomenon caused by the air in the high pressure circuit of the hydraulic oil.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of this invention, and FIG. 2 shows a hydraulic oil pipe. 2...Mission case, 8...Air reservoir, 3...
...Oil filter, 10...Float, 11,1
2...Reed switch, 13...Return pump, 1
4...Return pipe.

Claims (1)

[Scope of utility model registration request] An air reservoir is provided in the casing of the oil filter installed in the pipeline between the hydraulic oil pressure pump and the oil reservoir.
The air reservoir and the lower oil level of the oil reservoir are communicated by a return pipe with a return pump interposed therebetween, and a reed switch is installed at the position of the lowest allowable oil level in the air reservoir, and a float is attached with a magnet and can be raised and lowered. An air venting device for a hydraulic oil pipe, comprising a circuit for activating a reed switch to start a return pump by activating a reed switch when the float approaches an air reservoir, and a suitable means for automatically stopping the return pump.