JPS6032038B2 - Liquid pump for low lubricity liquids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid pump for conveying low lubricity liquids.

Conventionally, liquid pumps that convey low lubricity liquids such as water-soluble cutting oils or aqueous hydraulic oils have been known to cause liquid to flow out of the pump body from the rotating shaft where the sealing member comes into sealing contact due to the poor lubricity of the conveyed liquid. There was a drawback that leakage occurred within a short period of about one month.

The present invention solves the above-mentioned drawbacks by suppressing the wear of the rotating shaft portion and the sealing member that are in sealing contact with each other, and preventing liquid leakage to the outside of the pump body along the outer circumference of the rotating shaft for a long period of time. The present invention provides a liquid pump for use with low lubricity liquids.

For this reason, the present invention provides a sealing member that protrudes the end of the rotating shaft that operates the liquid conveying means provided in the pump body to the outside of the pump body and prevents liquid from leaking out of the pump body along the outer periphery of the rotating shaft. A rotating shaft portion provided in the pump body and in sealing contact with the sealing member is provided with a recess on the outer periphery, and the recess has an enlarged opening side and an enlarged recess on the closing side. is formed by thermally spraying a coating material to form a coating that improves the wear resistance of the rotating shaft portion with which the sealing member comes into sealing contact, and prevents wear of the rotating shaft portion with which the sealing member comes into sealing contact and the induction of damage to the sealing member due to this wear. Wear is kept to a minimum, and liquid leakage to the outside of the pump body along the outer periphery of the rotating shaft can be effectively prevented for a long period of time.

An embodiment of the present invention will be described below regarding a variable displacement vane pump.

In Figures 1 to 3, reference numeral 1 denotes a pump body of a variable displacement vane pump, and a housing hole 2 is provided inside to communicate with the low pressure side. A rotor 4 having a large number of vanes 3 movable in the radial direction is rotatably installed in a cylindrical movable ring 5. One side plate 7 is provided with arc-shaped suction holes 10 and discharge holes 11 that fit into the suction passages 8 and discharge passages 9 formed in the pump body 1.

12 is a pump chamber, 13 is a movable block, and 14 is a thrust block.

A piston 15 is movable in the same direction as the moving direction of the movable ring 5, and its tip abuts against the outer periphery of the movable ring 5 under the elastic force of a spring 17 housed in a spring chamber 16.
The movable ring 5 is pressed so that the amount of eccentricity is maximized.

Reference numeral 18 denotes an adjustment member provided opposite to the piston 15, which regulates the maximum discharge amount of the pump.

19 is an auxiliary spring.

A cover 20 is fixed to the pump body 1 and has a blind hole 21.

Reference numeral 23 denotes a rotating shaft with one end protruding outside the pump body 1, which is fitted with iron into the through hole 25 of the rotor 4 and connected with a key, as well as being positioned in the vertical direction using stoppers 24A and 24B.

Bearings 26A and 26B both rotatably support the rotating shaft 23.

27, 28 are outer lips 27A, 28A and spring theory 27C
, 28C presses the inner lip 27B in all directions of the stripe diameter.
, 28B as a sealing member is attached to the through hole 22 and is prevented from coming off by a stopper 35.

Reference numeral 29 denotes a flow path that passes between the bearing 26B and the sealing member 27 toward the low pressure side.

A recess is formed on the outer periphery of the rotating shaft 23 portion where the lips of the sealing members 27 and 28 come into sealing contact, and the opening 31 side is enlarged from the bottom 32 side, and both sides of the shaft are inclined. It is formed into a shape.

The lips 27A, 2 made of synthetic rubber are inserted into the recess 30.
When 7B, 28A, and 288 come into contact with each other in high-speed rotation in a pressed state to prevent leakage of a low-lubricity liquid, the coating material 34 is formed by thermal spraying with a coating material that can greatly improve the wear resistance performance of both.
The inner layer 34A of the coating 34 is thermally sprayed with a composite of alumina and nickel, which has oxidation resistance at high temperatures and serves as a bonding medium with the outer layer 34B of the coating 34. The outer layer 34B of the coating 34 is made of alumina as a ceramic material. A composite of titania and titania is thermally sprayed, and after cooling, the surface is smoothed by polishing so that it does not protrude beyond the outer periphery of the rotating shaft. Next, the action will be explained.

As the rotating shaft 23 rotates in the direction of arrow F, the liquid sucked in from the suction hole 10 is discharged into the discharge hole 11. When the discharge pressure increases, the movable ring 5 is moved against the spring 17 to a position approximately concentric with the rotor 4, thereby increasing the discharge amount. decrease. Rotating shaft 2 during operation of this pump
3. The sealing members 27 and 28 prevent the low-lubricity liquid from leaking out of the pump body along the outer periphery, and the rotary shaft 23 part that comes into sealing contact with the sealing member to prevent the low-lubricity liquid from leaking is Since the coating 34 is formed to greatly improve the wear resistance performance of the shaft, local wear on the shaft and wear induced on the sealing part due to this wear are minimized, and it can be used for a long time despite poor lubrication between the two. Leakage can be effectively prevented over a period of time. Furthermore, a recess 30 is formed along the outer periphery of the rotary shaft 23 portion with which the sealing member comes into sealing contact, and the recess is enlarged on the closed opening 31 side, and the coating material is thermally sprayed. It makes port spraying easy and gives a good spraying condition, and the coating 3.
4 can be difficult to damage or peel off.

Furthermore, by mounting multiple sealing members 27 and 28, each having an outer lip to prevent dust from entering and an inner lip to prevent external leakage, the inner sealing member 27 performs multiple functions. It is possible to reliably prevent dust and the like from adhering between the inner lip 27B and the rotating shaft 23, and also to fill the space between the inner lip 278 and the outer lip 28A with lubricating oil such as grease. , leakage can be effectively prevented for a long period of time.

It should be noted that when the pump of this example was applied to a device that had been experiencing liquid leakage for about a month, the pump was still in good condition even after more than a year had passed.

As described above, the present invention provides a sealing member that protrudes the end of the rotary shaft that operates the liquid conveying means provided in the pump body to the outside of the pump body, and prevents liquid from leaking out of the pump body along the outer periphery of the rotary shaft. is provided in the pump body, and a recess is formed around the outer periphery of the rotating shaft portion with which the sealing member comes into sealing contact, and the recess is enlarged on the closed side, and the recess is enlarged on the closed side. By forming a coating material that improves the abrasion resistance of the rotating shaft part where the sealing member makes sealing contact, the wear of the rotating shaft part and the sealing member that make sealing contact is suppressed to a minimum, and the sealing member is made to have a sealing contact with the rotating shaft part. Liquid leakage outside the pump body can be effectively prevented over a long period of time, and maintenance management can be simplified.

In addition, the coating material can be thermally sprayed easily to obtain a good thermal spraying condition, and the coating is difficult to be damaged or peeled off during assembly, handling, or polishing.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a variable displacement vane pump showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line RO to 0' in FIG. 1, and FIG. It is an enlarged sectional view of part m. 1... Pump body, 23... Rotating shaft, 27
, 28... sealing member, 30... dent,
34...Coating. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The end of the rotating shaft that operates the liquid conveying means provided in the pump body projects outside the pump body, and the pump body is provided with a sealing member that prevents liquid from leaking into the pump body along the outer periphery of the rotating shaft. A recess is formed along the outer periphery of the rotating shaft portion with which the sealing member comes into sealing contact, and the recess is enlarged on the opening side, and a coating material is thermally sprayed into the recess that is enlarged on the opening side. A liquid pump for low-lubricity liquids that has a coating that improves the wear resistance of the rotating shaft that the sealing member comes into sealing contact with.