JPH0640961Y2 - accumulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an accumulator, and more particularly to an accumulator of a high compression ratio resistant bladder type.

[Prior art and its problems]

Generally, the conventional bladder type accumulator is configured as shown in FIG. 4 and has a valve stem 32 for gas injection at one end and an oil inlet which is an oil inlet at the other end. Inside the elongated spherical shell 31 provided with the ports 33, the bladder 34 is arranged in a bag shape with the opening attached to the valve stem 32, and is the oil inlet. Shell 31 for oil port 33
A poppet 35 located inside is disposed.

Then, a gas having a predetermined pressure is sealed inside the bladder 34 located in the shell 31 via the valve stem 32, and in this state, the fluid is introduced into the oil port 33 so as to absorb the pulsation of the fluid. Has become.

However, in the accumulator configured as described above, the bladder 34 is shaped like a bag, the inner side of the bladder 34 is formed in the gas chamber 36, and the outer side is formed in the fluid chamber 37. Therefore, the fluid is oil port 33
The bladder 34 is compressed and the body of the bladder is deformed into a Y-shaped cross section (see FIG. 2 of Japanese Utility Model Laid-Open No. 58-45401). A crack is generated from a portion having a large bend caused by this deformation.

Further, since the gas in the gas chamber 36 is compressed when the working fluid pressure becomes high, the bladder 34 may be damaged when the ratio of the fluid pressure to the gas pressure becomes 3: 1 or more. Therefore, this type of accumulator has a structural problem when the working fluid pressure becomes high.

On the contrary, when the working fluid pressure decreases, the gas pressure in the gas chamber 36 causes the bladder 34 to expand until it comes into contact with the inner peripheral surface of the shell 31. As a result, the wall thickness of the bladder 34 becomes thin, so that the material of the bladder becomes systematically sparse and gas permeates to the fluid side,
The pressure of the gas chamber is reduced and the function as an accumulator is reduced. Further, since the bladder 34 is in contact with the poppet 35 in a thin state, the bladder 34 may enter the gap between the poppet 35 and the oil port 33 and be damaged from the inserted part.

As another conventional technique for preventing this damage, instead of the poppet, the outlet of the oil port 33 is covered with a plate member,
There is a plate member that allows a fluid to pass through the through hole (Japanese Utility Model Publication No. 55-130902). However, this hole cannot be made smaller due to processing (φ
With a drill of 4 or less, the drill breaks during processing. ), The bladder will enter this hole and be damaged. This bladder damage problem is still presently unsolvable.

The present invention solves the above-mentioned problems of the conventional ones, there is no possibility of damaging the bladder even when high pressure is applied, and the fluid pressure below the gas charging pressure of the bladder is maintained. An object of the present invention is to provide an accumulator capable of improving the life of the bladder without the possibility of damaging the bladder even when it acts.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems of the prior art, and its technical means is configured as follows. That is, a shell having a vacant chamber and a hole for a flow path communicating with the vacant chamber, and having a mouth portion that is hermetically attached to surround the hole of the shell, divides the vacant chamber into a gas chamber and a fluid chamber. A bladder made of a rubber-like elastic material in the shape of a bag, and a head arranged in the bladder and fixed to the shell, projecting integrally from the mounting portion to the bottom side of the bladder, and the tip facing the bottom surface of the bladder And a plurality of fins protruding in the longitudinal direction formed in the direction of the head and the mounting portion on the outside, An inner tube made of a hard material is provided in a valley portion between the fin and the fin, the slit having a slit communicating with the bladder side from the flow passage in a direction substantially the same as the longitudinal direction of the fin.

[Action]

In the accumulator of the present invention, when the working fluid flows in from the circulation hole, it flows into the flow passage of the inner tube. This working fluid also acts on the bladder through the slit.
Then, the pulsation or the like of the working fluid pressure is absorbed. In this situation,
When the working fluid pressure becomes high, the bladder is bonded to the inner peripheral surface of the shell. Therefore, even if the high pressure exceeds the allowable limit, the bladder is supported by the inner peripheral surface of the shell and does not exceed the elastic limit. On the contrary, when the working fluid pressure becomes lower than the gas pressure, the bladder is joined to the inner tube by the gas pressure. Then, the joint surface of the bladder is bonded to each fin of the inner tube. Therefore, the bladder does not cause abnormal deformation due to gas pressure or relative sliding with the inner tube.

〔Example〕

 An embodiment of the present invention shown in the drawings will be described below.

1 to 3 show an accumulator according to the present invention, in which one end is open and the other end is closed, and the other end of the shell 1 is for filling gas inside. A valve stem 2 is provided, and a protector 4 for preventing damage to the bladder 3 is attached to a portion of the valve stem 2 located inside the shell 1.

An inner tube 15 as shown in detail in FIG. 3 is inserted from one end into the shell 1, and the bladder 3 is provided outside the inner tube 15 as shown in FIGS. 1 and 2. Has been fitted.

That is, as shown in FIG.
Is the first inner tube 16 and the first inner tube 16 in order to have the strength of the first inner tube 16.
A second inner tube 18 which is inserted into the hollow part 17 of the above and is fitted and attached to form an integral body. The inner tube 16 has a cylindrical shape with one end closed, and the central part is in the outer peripheral direction. The recesses 19 are formed in four equal distributions, the longitudinal surfaces of which are inclined surfaces 19a, 19a, and the bottoms of the recesses 19 communicate with the hollow portions 17, and therefore the adjacent recesses 19, 19 are formed.
The portions formed between the gaps are fins 20, and the fins 20 are formed in four equal intervals in the circumferential direction.

Further, the second inner tube 18 has a plurality of slits 21, 21, ... Formed on the peripheral surface thereof and can be inserted into the hollow portion 17 of the inner tube 16 so as to be hollow. When the inner tube 18 is inserted into the portion 17, the inner tube 18 is fitted and attached to the inner tube 16 to be integrated, and each slit 2 provided in the inner tube 18 is provided.
.. are located inside the recessed portion 19 of the inner tube 16.

Further, the bladder 3 is provided outside the inner tube 16.
, And the lower end of the bladder 3 is sandwiched between the outer peripheral surface of the inner tube 16 and the inner peripheral surface of the shell 1.

Reference numeral 23 is a lid member that is screwed into one end opening of the shell 1 and has a hole 22 for fluid inflow formed in the center thereof.

Next, the operation of the accumulator according to the present invention constructed as above will be described.

First, gas is enclosed in a gas chamber formed between the shell 1 and the bladder 3 via a valve stem 2 provided at the end of the shell 1, and the hole 22 of the lid member 23 is connected to the flow path side. Connect to.

Then, when pressure fluctuation occurs on the flow path side, the pressure is introduced into the inner tube 18 through the hole 22 of the lid member 23, and this pressure is applied to each slit formed in the inner tube 18. It acts on the inner surface of the bladder 3 via 21, 21, ..., to balance the pressure of the gas enclosed between the bladder 3 and the shell 1 with the pressure in the flow path. Is greater than the gas pressure, the bladder 3 is expanded, and when the flow channel pressure is small, the bladder 3 is contracted so that the pressure change in the flow channel is absorbed. Has become.

The bladder 3 is supported by the shell 1 when the working fluid pressure exceeds the allowable limit, and when the working fluid pressure becomes lower than the gas pressure, the first inner tube 16 and the second inner tube 18 It is supported by the (inner tube) to maintain the original thick state and prevent abnormal deformation. This also prevents the gas from penetrating to the fluid side. Also, the bladder is prevented from sliding on the inner tube due to the action of gas pressure, because the surface joined to each fin is pressed against the fin by gas pressure. Further, since the longitudinal fins apply tension to the bladder in the circumferential direction as well as the axial direction, even if a gas pressure acts on the bladder, a part of the bladder is prevented from entering the slit. If the shape of the inner tube is large and it is difficult to process the slits, the second inner tube 18 can be attached to the milling machine and subjected to slipping to easily process a narrow slit. Yes (processing time is 1/15 to 20 when drilling many holes). At this time, the suriware has a disk shape and rotates in the circumferential direction (since it does not have a small diameter like a drill), it is not damaged during processing even if the thickness becomes thin. Therefore, it is possible to form a slit having a narrow width.

In addition, it is preferable that the outer circumference of the head, which is the free end of the inner tube, corresponds to the sectional inner diameter of the bladder.
For example, in the case of FIG. 1, the outer circumference of the head is formed in a circular shape and the corners are formed in a round shape.

[Effect of device]

The accumulator of the present invention has the following effects.

The pressure fluid flows into and out of the passage hole provided in the accumulator and acts on the bladder. When the working fluid pressure becomes lower than the pressure of the gas chamber, the gas pressure causes the bladder to be pressed against the inner tube. As a result, the wall thickness of the bladder remains almost unchanged and does not become thin. Further, since the bottom surface of the bladder abuts on the head portion of the inner tube, it is possible to prevent the inner tube from being greatly contracted in the mounting portion direction (axial direction) and to prevent damage due to abnormal deformation. Furthermore, the body part of the bladder is pressure-bonded to both side surfaces of the fin by gas pressure so that tension is exerted on the body part between the fins and the circumferential direction between the fins of the inner tube and the fin peripheral surface. Relative sliding (friction with the slit) is prevented. At the same time, the body part is also provided with tension in the axial direction of the body part by the fins formed longitudinally in the direction of the head part and the mounting part. It also prevents a part of the body from entering. As a result, it is possible to effectively prevent the bladder from being damaged by the slit.

In particular, slits can be processed by slipping, so it can be processed to a width of 1 mm or less (because the only way to make the flow path a hole like a conventional example is to use a drill, so it can be processed to φ4 mm or less. If this is done, the drill will be damaged due to the thickness of the processed member, and a porous material such as ceramics will be damaged without pressure resistance.) The narrower the width of the slit, the more difficult it is for part of the bladder to enter, so the formation of the slit can further prevent damage to the bladder.

The bladder is thick so as to withstand gas pressure. Therefore, it is effective to expand and contract the body portion of the bladder to absorb the pulsating pressure and the like. Since the inner tube is provided with a slit corresponding to the axial direction of the body portion of the bladder, the pressure fluid flowing in from the passage hole is
When passing through the slit, it acts on the inner surface of the bladder by forming a surface pressure in a linear manner. Moreover, circumferential flow is suppressed by the fins on both sides. Therefore, the body portion of the bladder is expanded to the maximum in the center, so that the pulsation absorbing ability which is superior to the prior art is exhibited. Also, this does not give undue deformation to the bladder, thus providing durability.

Since the slit provided in the inner tube is formed in the longitudinal direction, the fluid resistance is small and the response capability to the working fluid is excellent as compared with the holes of the related art.

When the side surface of the fin of the inner tube is formed to have a slope as in claim 2, when the bladder is pressed against the fin by gas pressure, the pressure bonding effect is excellent and the sliding of the bladder with the trough is suppressed. It is possible to effectively prevent the bladder from being damaged by friction with the slit portion.

When the slit of the inner tube is intermittent as in claim 3, the entire length of the body portion of the bladder can be expanded and absorbed, the pulsation absorbing ability can be improved, and the durability can be improved. You can

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an accumulator according to the present invention,
2 is a schematic sectional view showing the relationship between the inner tube and the bladder, FIG. 3 is a schematic exploded view showing the inner tube,
FIG. 4 is a schematic sectional view showing a conventional accumulator. 1, 31 …… Shell 2, 32 …… Valve stem 3,34 …… Bladder 4 …… Protector 5,15 …… Inner tube 6,16 …… First inner tube 6a …… Base 6b …… Tip 8, 18 …… Second inner tube 10,20 …… Fin 11,21 …… Slit 17 …… Hollow part 19 …… Dent part 22 …… Hole 23 …… Lid member 33 …… Oil port 35 …… Poppet 36 …… Gas chamber 37 ... Fluid chamber

Claims (3)

[Scope of utility model registration request] 1. A vacant chamber and a flow path hole (2) communicating with the vacant chamber.
2) and a shell (1) having a hole (2) in said shell (1)
A bladder (3) made of a rubber-like elastic material in the form of a bag, which has a mouth portion that surrounds 2) and is hermetically attached to partition the empty chamber into a gas chamber and a fluid chamber, and the bladder (3) Has a mounting portion fixed to the shell (1) and integrally protruding from the mounting portion to the bottom surface side of the bladder (3) and has a head portion at the tip facing the bottom surface of the bladder. , A plurality of fins (20) having a flow passage communicating with the hole (22) and closed by the head portion inside, and protruding at the outside in the direction of the head portion and the attachment portion with a long length (20) And a slit (21) communicating with the bladder (1) side from the flow passage in a valley portion between the fin (20) and the fin (20) in a direction substantially the same as the longitudinal direction of the fin (20). The accumulator provided with the inner tube made from a hard material for gas pressure resistance which has these. 2. The accumulator according to claim 1, wherein the opposed surfaces of the fins (20) of the inner tube are formed as inclined surfaces. 3. The accumulator according to claim 1, wherein the slit of the inner tube is formed intermittently.