JPH0438082Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) This invention relates to a bladder for an accumulator in a fluid supply path, and is designed to smoothly deform in response to changes in the pressure of fluid such as water flowing through the fluid supply path, that is, the internal pressure of the bladder. It is something. (Prior Art) As an accumulator, the one shown in FIG. 7 is known. In FIG. 7, reference numeral 1 denotes a rubber bladder for an accumulator, which includes a ring-shaped opening edge 1a at the lower end, a cup-shaped movable part 1b integrally formed inside the upper end, and whose diameter decreases upward. The opening edge 1a is sandwiched and fixed between the outer periphery of the dish-shaped lid 2 and the lower edge inner periphery of the bell-shaped can 3, and the gas supply valve 4 at the top of the can A gas such as nitrogen is sealed in the body 3 at a predetermined pressure, and a fluid supply/discharge port 5 at the center of the lid body 2 is connected to a fluid supply path (not shown) such as water to supply and discharge fluid. The fluid flows into the movable portion 1b of the bladder 1 through the port 5, and the movable portion 1b of the bladder 1 repeatedly expands and contracts in response to the pressure of this fluid. However,
The movable part 1b of the bladder 1 described above has a wall thickness of about 3 mm and a volume of about 500 c.c., so the shape changes due to expansion and contraction of the movable part 1b due to changes in fluid pressure. Larger, especially fluid pressure decreases,
If the movable part 1b collapses and falls onto the lid 2, the shape of the movable part 1b will not return to its original shape even if the fluid pressure is restored, and the volume of the movable part 1b will no longer correspond to the fluid pressure. As a result, the functional reliability of the accumulator was reduced. Therefore, in the past, a rib was provided on the inner surface of the movable part 1b in a spiral or axial direction, or a support tube for the movable part 1b was provided inside the bladder 1.
Attempts have been made to prevent this from collapsing. (Problems to be solved by the invention) If ribs are spirally provided on the inner surface of the movable part 1b, it is difficult to manufacture the bladder 1 by molding, and the ribs are difficult to manufacture when manufacturing a low-height item. There was a problem that the desired effect could not be obtained due to the short length. In addition, when ribs are provided in the axial direction on the inner surface of the movable part 1b, molding is easy, but the thin parts between the ribs tend to expand laterally, and when the ribs expand, the outer surface of the movable part 1b There was a problem that it came into contact with the inner wall of the can body 3 and was damaged. Further, when a support cylinder is inserted inside the bladder 1, there is a problem that the inner surface of the movable part 1b comes into contact with the support cylinder when the movable part 1b contracts, causing wear and tear. It has been attempted to form a dimple-like recess on the outer surface of the movable portion 1b and make the inner surface protrude, but in this case, it is difficult to integrally mold the movable portion 1b, and the manufacturing cost increases. Ta. This idea prevents the movable part 1b from collapsing and causing the inner surface of the movable part 1b to touch or fall when the fluid pressure decreases and the pressure inside the movable part 1b becomes significantly smaller than the pressure outside. The purpose of the present invention is to provide a bladder that maintains the reliability of its function as an accumulator, is easy to manufacture by molding, and does not come into contact with the outer can body when inflated. (Means for solving the problem) Ribs with a semicircular cross section are formed in an endless zigzag pattern consisting of a plurality of chevrons on the inner surface of the portion above the lower edge of the movable part 12 of the bladder 10, and the zigzag pattern is formed. The valley portion 13a of the rib 13 is protruded so as to be located near the lower edge of the movable portion 12, and the top portion 13b of the rib 13 drawing the zigzag pattern is formed into a spear shape extending upward. (Function) Since the rib 13 is formed in a zigzag shape in the lower part of the movable part 12, that is, in the part with a large diameter, the vertical and horizontal expansion of the movable part 12 is suppressed, and the rib 13 is While this prevents contact, when it contracts, the thinner parts between the ribs 13 contract first, which prevents the movable part 12 from collapsing and folding tightly. It easily recovers to its original shape, the movable part 12 expands and contracts in accurate response to fluid pressure, and the volume of liquid discharged from the accumulator becomes constant. Further, above the zigzag pattern portion, the top portion 13b of the rib 13 drawing the zigzag pattern extends in a spear shape.
Vertical elongation is suppressed and collapse during contraction is prevented. Although there are no horizontal ribs in this part, since the diameter is narrow in this middle part, the horizontal expansion due to pressure is small and the can body 3
There is little risk of coming into contact with. Further, although there is no rib 13 at all in the upper part, the diameter in this part becomes even thinner and is closed at the upper edge, so even without the rib, the rigidity is high, and the can body expands. There is almost no risk of contact with 3, and there is also little risk of collapse due to contraction. (Example) In FIGS. 1 and 2, the opening edge 11 of the bladder 10 is formed into a ring shape with an inner diameter d of 100 mm, an outer diameter D of 116 mm, and a height h of 10 mm.
A cup-shaped movable portion 12 with a height H of 120 mm and a volume of 1 was integrally formed inside the upper edge of 1. However, the wall thickness of the movable part 12 was set to a maximum of 3.3 mm at the bottom and a minimum of 1.3 mm at the top. and,
On the inner surface of the movable part 12, an endless zigzag rib 13 in the shape of connecting three chevrons is provided at the valley part 1.
3a is provided in a protruding manner so as to be located at the boundary between the movable part 12 and the opening edge 11. However, in this example,
The peak 13b of the rib 13 is formed into a spear shape extending upward, and the height V of the tip thereof is set to 80 mm, and the included angle between the zigzag portion and the spear-shaped peak 13b is set to 120 degrees. 3), the above rib 13
As shown in Fig. 4, the radius of curvature R is 5.
mm, the width b at the valley part 13a is set to 8 mm, the height t is set to 2 mm, and these are the maximum,
The above-mentioned width b and height t are gradually decreased toward the tip of the lance-shaped top portion 13b. Note that the opening edge 11 is
It is shaped like a belt with a rectangular cross section with a height h of 10 mm and a width of 8 mm, and has an outer surface groove 11a with a radius of curvature of 3 mm and a depth of 0.5 mm on the outer surface (see Fig. 5), and a groove with a radius of curvature of 1.5 mm and a depth on the bottom surface. Bottom grooves 11b each having a length of 0.5 mm were formed. The bladder 10 described above was attached to the can body 3 shown in FIG. That is, as shown in FIG. 6, the opening edge 11 of the bladder 10 is fitted onto the edge 2a of the outer periphery of the lid 2, which has an L-shaped cross section, and the lower part of the can body 3 is fitted onto the outer surface of this opening edge 11. The lower end opening 3a is fitted into the lower end opening 3a.
Fold the end edge 3b inward and overlap it with the lower surface of the edge 2a of the lid 2.
The lower end opening 3a of the can body 3 and the outer peripheral edge 2a of the lid 2 were caulked so that the bottom groove 1a and the bottom groove 11b would disappear due to deformation. In the above structure, the internal pressure and external pressure of the bladder 10 are changed as shown in the table below, and the movable part 1
2 was expanded and contracted. The differential pressure at this time and the discharge amount (cc) of the bladder 10 are also shown together with the amount of variation.

[Table] During this experiment, we observed changes in the shape of the movable part 12 of the bladder 10, and found that in numbers 1 to 5 where the differential pressure was negative, the ribs were used as bones and contracted into an umbrella-like shape, but they did not fall over. Number 6, where there is no positive differential pressure and close to zero;
Numbers 7 and 11 maintained almost the same shape as when installed, and numbers 8 to 10 and 12 to 14, where the differential pressure was positive, expanded in the vertical and horizontal directions but did not contact the side wall. That is, through this experiment, it was confirmed that the movable part 12 does not fall over even if it becomes flat when the internal pressure decreases, and that the movable part 12 smoothly expands and contracts according to the pressure difference between the inside and outside. In other words, since the ribs 13 are formed in a zigzag shape consisting of a series of chevrons, the thin walled portions between the ribs 13 have a relatively small resistance to external force, and when the external pressure increases, the thin walled portions between the ribs 13 The movable portion 12 is recessed inwardly, thereby causing the movable portion 12 to contract in the longitudinal and lateral directions. On the other hand, the rib 13 portion has a large resistance force against external force, so there is little deformation, and the rib 13 portion forms a skeleton, so deformation of the movable part 12 due to external pressure is not complicated, and This prevents the movable part 12 from collapsing and falling down, and prevents the inner surfaces of the movable part 12 from coming into close contact with each other. and,
Since the ribs 13 are present over a wide range, each part of the movable part 12 deforms uniformly when the movable part 12 contracts due to an external force, and the stress in each part becomes uniform. Therefore, when the internal pressure starts to rise and becomes larger than the external pressure, the stress is uniformly applied to each part, and the thin parts between the ribs 13 are quickly removed due to the strong spring action of the ribs 13. to return to its original form. Since the ribs 13 are formed in a zigzag shape, the resistance to external forces is large in both the vertical and lateral directions, so even when a sudden increase in internal pressure occurs, the deformation of the movable part 12 is suppressed. Furthermore, since the ribs 13 are present in the lower half of the movable part 12 and not in the upper half, the movable part 12 tends to extend more in the vertical direction than in the horizontal direction, and only the upper half of the can body. Contact with the inner surface of 3 is prevented. In addition, the top part 13 of the rib 13 that draws a zigzag pattern
b is formed into a spear shape extending upward, so that when an external force is applied, the deformation of the upper and lower parts of the movable part 12 is more uniform, the collapse due to external pressure is further reduced, and the longitudinal expansion when the internal pressure increases is further encouraged. Furthermore, in this embodiment, since the outer surface groove 11a and the bottom surface groove 11b are provided in the opening edge 11 of the bladder 10, the opening edge 11 can be compressed by compressing only the portion outside the grooves 11a and 11b. 2 and the lower edge opening 3a of the can body 3, a high degree of airtightness can be easily obtained. (Effect of the invention) This invention forms the ribs on the inner surface of the bladder into an endless zigzag pattern consisting of a plurality of consecutive chevrons, is provided above the lower edge of the movable part, and moves the top of the ribs forming the zigzag pattern upward. By extending it into a spear shape, the thick lower part of the cup-shaped movable part is thin at the top and thick at the bottom, and the ribs are formed in a zigzag shape, and the ribs are formed in the vertical direction in the middle part, which is slightly thinner. from,
In the lower part of the movable part, which has a large diameter and is easily deformed both vertically and horizontally, the zigzag ribs increase the resistance force in both the vertical and horizontal directions, while the diameter is slightly thinner and allows it to expand in the horizontal direction. In the middle part, which has a small amount of elasticity and is relatively easy to expand vertically, the longitudinal resistance increases due to the spear-shaped ribs, and the movable part may collapse and fall down due to an increase in external pressure or a decrease in internal pressure, or it may collapse horizontally when internal pressure increases. It does not extend in any direction and touch the can body, and always expands and contracts in response to changes in internal and external pressure. This improves the reliability of the accumulator's function and makes it easy to manufacture by molding. There is no need to provide a conventional support tube inside the bladder movable part.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of this invention, Fig. 2 is a bottom view of Fig. 1, Fig. 3 is a developed view of the ribs, and Fig. 4 is a longitudinal sectional view of an embodiment of this invention.
The figure is a cross-sectional view of the rib, Figure 5 is a cross-sectional view of the opening edge of the bladder, Figure 6 is a cross-sectional view of the bladder opening edge when the accumulator is assembled, and Figure 7 is a longitudinal cross-sectional view of a conventional accumulator. . 10... Bladder, 11... Opening edge, 12...
Movable part, 13...rib.

Claims (1)

[Claims for Utility Model Registration] [1] Consisting of a ring-shaped opening edge and a cup-shaped movable part that is integrally formed inside the upper end of the ring-shaped opening edge and whose diameter decreases upward, a predetermined pressure is applied to the outside of the movable part. In the Prada for an accumulator, the inside of the movable part is connected to a fluid supply path so that the movable part repeatedly expands and contracts according to the pressure of the fluid, and the movable part is located above the lower edge of the movable part. Ribs with a semicircular cross section are protruded from the inner surface of the part in an endless zigzag pattern consisting of a plurality of chevrons, and the valleys of the zigzag pattern are located near the lower edge of the movable part, and the zigzag pattern is 1. A bladder for an acumulator of a fluid supply path, characterized in that the top of the rib that depicts the shape is formed into a spear shape extending upward. [2] The bladder for an accumulator of a fluid supply path according to claim 1, wherein grooves are provided in the circumferential direction on the lower and outer surfaces of the ring-shaped opening edge, respectively.