July 7, 2016 - 5:22 PM EDT
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Patent Issued for Accumulator (USPTO 9377031)

By a News Reporter-Staff News Editor at Journal of Engineering -- Eagle Industry Co., Ltd. (JP) has been issued patent number 9377031, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventor is Miyake, Kuniaki (Fujisawa, JP).

This patent was filed on May 17, 2013 and was published online on June 28, 2016.

From the background information supplied by the inventors, news correspondents obtained the following quote: "The present invention relates to an accumulator which is used as a pressure accumulator or a pulsation pressure damping device. The accumulator according to the present invention is used, for example, in a hydraulic system for a motor vehicle or a hydraulic system for an industrial equipment.

"Conventionally, as shown in FIG. 6, there has been known an accumulator 51 structured such that an accumulator housing 52 is provided with an oil port 53 which is connected to a pressure piping (not shown) of equipment, an internal portion of the accumulator housing 52 is sectioned into a gas chamber 56 filling the gas, and a fluid chamber 57 communicating with the oil port 53, by a bellows 54 and a bellows cap 55, and the accumulator 51 is activated to accumulate pressure and damp pulsation pressure on the basis of movement of the bellows cap 55, and extension and contraction of the bellows 54 so that gas pressure and liquid pressure balance (Japanese Unexamined Patent Publication No. 2005-098391).

"Further, the accumulator 51 is provided with a safety mechanism 61 which prevents the bellows 54 from being damaged due to the unbalance between the gas pressure and the liquid pressure in the case that the pressure of the fluid chamber 57 is decreased together with the pressure decrease of the pressure piping. In other words, in the case that the pressure of the pressure piping is extremely decreased due to the operation stop of the equipment, the liquid (oil) within the fluid chamber 57 is discharged little by little from the oil port 53, the bellows 54 is expanded little by little by the filled gas pressure according to the liquid discharge, and the bellows cap 55 comes into contact with a seal 62 which is installed in the inner surface of the housing 52 so as to form a so-called zero-down state. In the zero-down state, the fluid chamber 57 is occluded by the seal 62 (a spatial position closer to an outer peripheral side than the seal 62 among the fluid chamber 57 is occluded), a part of the liquid is trapped within the fluid chamber 57, and the pressure of the trapped liquid and the gas pressure of the gas chamber 56 are balanced. Therefore, the bellows 54 is inhibited from being damaged due to an excess stress applied to the bellows 54.

"However, in the prior art mentioned above, there is a case that a lip 62a of the seal 62 is inverted and is pinched between the seal retaining portion 63 and the bellows cap 55 as shown in FIG. 7B, in place of the case that the seal 62 comes into contact with the bellows cap 55 in a normal attitude as shown in FIG. 7A. There is a case that the seal 62 is damaged for the reason of the pinching, and the safety mechanism 61 is not activated so as to make the bellows 54 be damaged."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventor's summary information for this patent: "Problem to be Solved by the Invention

"The present invention is made by taking the above points into consideration, and an object of the present invention is to provide an accumulator which can inhibit a seal installed in an inner portion of a housing from being pinched between a seal retaining portion in an inner peripheral side and a bellows cap, thereby inhibiting the seal and the bellows from being damaged.

"Means for Solving the Problem

"In order to achieve the object mentioned above, an accumulator according to a first aspect of the present invention is an accumulator comprising:

"an accumulator housing which is provided with an oil port connected to a pressure piping of equipment;

"an inner portion of the accumulator housing being sectioned into a gas chamber filling with gas and a fluid chamber communicating with the oil port by a bellows and a bellows cap;

"the bellows cap sealing the fluid chamber by coming into contact with a seal on the basis of movement in a stroke in the case that a pressure of the pressure piping is decreased; and

"the seal being retained by a seal retaining portion which is provided in an inner peripheral side of the seal,

"wherein a seal diameter of the seal is set to be larger than an effective diameter of the bellows at a position where the seal comes into contact with the bellows cap.

"Further, an accumulator according to a second aspect of the present invention is the accumulator described in the first aspect, wherein the seal has a seal lip, and the seal lip is a seal lip having a tongue shape in its cross section or a triangular shape in its cross section.

"According to the new knowledge of the inventors of the present invention, the generation of the pinching of the seal in the prior art is caused by the following reasons.

"More specifically, in the case that the pressure of the pressure piping is decreased by the operation stop of the equipment, the liquid (the oil) within the fluid chamber is discharged little by little from the oil port, the bellows is expanded little by little due to the pressure of the filled gas according to this, and the bellows cap moves at a stroke in a direction in which the bellows cap comes close to the seal installed in the inner surface of the housing. Further, just before the bellows cap comes into contact with the seal, the flow directed to the oil port is generated in the liquid which is pushed away by the bellows cap moving at the stroke, and the seal is pressed by the flow. As a result, the seal is deformed, and the pinching is generated. Just before the bellows cap comes into contact with the seal, the distance between the seal retaining portion provided in the inner peripheral side of the seal and the bellows cap becomes narrower and the direction of the flow is unified. Accordingly, the seal is strongly pressed in a state in which the flow becomes stronger.

"Further, according to the new knowledge of the inventors of the preset invention, just before the bellows cap comes into contact with the seal, a part of the liquid pushed away by the bellows cap moving at the stroke flows inward (inward in a diametrical direction) toward the oil port, the other part thereof inversely flows outward (outward in the diametrical direction) toward the fluid chamber, and it is found that a position which should be called as a divide of these two flows is a position of an effective diameter of the bellows. In other words, since the seal diameter (the diameter of the rip end) of the seal which is the position at which the seal comes into contact with the bellows cap is smaller than the effective diameter of the bellows in the prior art mentioned above, the seal is pressed by the inward flow so as to be deformed inward. As a result, the pinching is generated.

"On the contrary, according to the present invention, since the seal diameter (the diameter of the lip end) of the seal which is the position at which the seal comes into contact with the bellows cap is set to be larger than the effective diameter of the bellows, the seal is not pressed by the inward flow, and even if the seal is pressed, the seal is not pressed by the inward flow but is pressed by the outward flow. Therefore, the seal is not deformed inward by being pressed by the inward flow. As a result, it is possible to inhibit the seal from being pinched between the seal retaining portion and the bellows cap. The effective diameter of the bellows is the same as the outer diameter of the piston in the case that the bellows is assumed as the piston pushing away the liquid (the oil) when the bellows achieves the action of pushing away the liquid (the oil) on the basis of expansion and contraction.

"The operation and effect of the present invention is particularly significantly achieved in the seal provided with the seal lip, and the seal lip includes the seal lip having the tongue shaped cross section and the seal lip having the triangular shaped cross section. These seal lips conventionally have the risk that the seal lips are pinched between the seal retaining portion and the bellows cap so as to be damaged. However, according to the present invention, it is possible to inhibit the pinching from being generated in the seal lips.

"Effect of the Invention

"The present invention achieves the following effects.

"More specifically, since the seal diameter of the seal is set to be larger than the effective diameter of the bellows as described above in the present invention, the seal is not deformed inward by being pressed by the inward flow of the liquid. Therefore, it is possible to inhibit the seal from being pinched between the seal retaining portion and the bellows cap by being deformed inward. As a result, it is possible to prevent the seal from being damaged, prevent the safety mechanism from not being activated, and prevent the bellows from being damaged."

For the URL and additional information on this patent, see: Miyake, Kuniaki. Accumulator. U.S. Patent Number 9377031, filed May 17, 2013, and published online on June 28, 2016. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9377031.PN.&OS=PN/9377031RS=PN/9377031

Keywords for this news article include: Eagle Industry Co. Ltd.

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Source: Equities.com News (July 7, 2016 - 5:22 PM EDT)

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