Screw pump

Inactive Publication Date: 2019-03-14
DENSO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present disclosure aims to prevent the break-in of extraneous material that can cause the screw pump to stop operating. It provides a lock-prevention portion that prevents the driving and driven sides of the screw members from becoming locked together. This prevents the pump from becoming completely inoperable and increases its reliability. It also avoids the need for a lock-prevention mechanism outside the pump housing, reducing the size of the screw pump.

Problems solved by technology

In the screw pump of the above prior art, since the extraneous material is trapped by use of its gravity, it is difficult to completely trap the extraneous material when suction speed of the working fluid is high.
In addition, since the trap member is formed at the side wall of the pump housing, it is a problem that a size of the screw pump becomes larger.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

(Structure)

[0033]At first, an entire structure of a fuel supply system 90, to which a screw pump 101 is applied, as well as a detailed structure of the screw pump 101 will be explained with reference to FIGS. 1 to 3.

[0034]As shown in FIG. 1, the fuel supply system 90 includes a fuel level sensor 92, a suction filter 93, the screw pump 101, a fuel filter 94 (indicated by F / F in FIG. 1) and a pressure regulator 95, each of which is provided in a fuel tank 91. The fuel supply system 90 further includes a high pressure pump 96 and a fuel injection device 97, both of which are provided at positions neighboring to an internal combustion engine 98 (indicated by E / G in FIG. 1 and hereinafter, the engine 98). The fuel supply system 90 supplies fuel F, such as, gasoline, from the fuel tank 91 to the engine 98.

[0035]As shown in FIGS. 1 and 2, the screw pump 101 draws the fuel F, which is filtered at the suction filter 93, from the fuel tank 91 via a suction port 11 and pressurizes the fuel F s...

second embodiment

[0062]A screw pump 102 according to a second embodiment will be explained with reference to FIG. 4. The screw pump 102 of the second embodiment is different from the screw pump 101 of the first embodiment in a structure or a shape of the female screw accommodation hole.

[0063]As shown in FIG. 4, a stepped portion 28 is formed in a female screw accommodation hole 232 of a pump housing 202, wherein the stepped portion 28 extends in the axial direction. The stepped portion 28 is formed at a position, which is separated in the radial cross section from the forward-side boundary portion 24 in a circumferential direction of the female screw accommodation hole 232, more exactly, at a position separated from the forward-side boundary portion 24 in the rotational direction (in the anti-clockwise direction Rf) by an angle of 120 degrees. An inner diameter of the female screw accommodation hole 232 in a first inner surface area between the forward-side boundary portion 24 and the stepped portio...

third embodiment

[0068]A screw pump 103 according to a third embodiment will be explained with reference to FIG. 5. The screw pump 103 of the third embodiment is different from the screw pump 102 of the second embodiment in the structure or the shape of the female screw accommodation hole.

[0069]In FIG. 5, a dotted line indicates the inner peripheral wall of the female screw accommodation hole 232 of the second embodiment, that is, the inner peripheral wall for the first inner surface area (the first female-side clearance “CLf1”) formed between the forward-side boundary portion 24 and the stepped portion 28.

[0070]As shown in FIG. 5, an inner peripheral wall of a female screw accommodation hole 233 is formed in such a way that an inner diameter of the female screw accommodation hole 233 is gradually decreased in the rotational direction (in the anti-clockwise direction Rf) of the female screw member 5 in the first inner surface area from the forward-side boundary portion 24 to a circumferential interm...

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PUM

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Abstract

A screw pump has a male screw accommodation hole and a female screw accommodation hole formed in a pump housing. A male screw member and a female screw member are respectively accommodated in the male screw accommodation hole and the female screw accommodation hole. A male-side clearance is formed in a radial direction between the male screw member and the male screw accommodation hole and a female-side clearance is formed in the radial direction between the female screw member and the female screw accommodation hole. The female-side clearance is made to be larger than the male-side clearance, so that the female screw member can easily move in a direction away from the male screw member to the female-side clearance when any extraneous material is going to be wedged between the male screw member and the female screw member, to thereby prevent a locked condition of the screw members.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is based on Japanese Patent Application No. 2017-173796 filed on Sep. 11, 2017, the disclosure of which is incorporated herein by reference.FIELD OF TECHNOLOGY[0002]The present disclosure relates to a screw pump for pressurizing and pumping out working fluid by use of rotation of screw members.BACKGROUND[0003]The screw pump is known in the art, for example, as disclosed in Japanese Patent Publication No. 2004-36547. In the screw pump, working fluid is pressurized and pumped out by rotation of multiple screw members. A radial gap between the screw members as well as a radial gap between the screw member and a pump housing is generally very small, for example, several ten micro-meters (μm). In a case that extraneous material enters a working chamber of the screw pump, the extraneous material may enter the radial gap and may be wedged between the respective parts.[0004]In the screw pump of the above prior art (JP2004-36547), ...

Claims

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Application Information

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IPC IPC(8): F04C2/16F04C13/00
CPCF04C2/16F04C13/005F04C13/008F04C14/28F04C2280/02
InventorINOUE, MASASHITAKEUCHI, YASUHIROHIDAKA, YUUJITAKAGI, MASATOSHI
OwnerDENSO CORP