JP3337206B2 - Bellows and fluid equipment using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bellows used for circulating and transferring a chemical solution in, for example, a semiconductor manufacturing apparatus, and a fluid device such as a bellows pump and a pulsation damping device using the same.

[0002]

2. Description of the Related Art For example, in a semiconductor manufacturing apparatus, fluid equipment such as a bellows pump for circulating and transferring a chemical solution and a pulsation damping device for attenuating pulsation of a chemical solution discharged from the bellows pump is used. Such a device uses a bellows made of a synthetic resin as a main component thereof.

As this type of bellows, there is a bellows manufactured by cutting a cylindrical member made of, for example, polytetrafluoroethylene (PTFE) with a lathe using a stick bite or the like. The bellows 100 shown in FIG. 10 is manufactured by such a cutting process. In a trunk portion 100c located between an opening peripheral portion 100a and a closed end portion 100b, a peak portion 101 and a valley portion 102 are formed. It has a bellows shape provided alternately, and has a disc-shaped side portion 1 between the peak portion 101 and the valley portion 102.
03 are continuously provided, and the ridges 101, the valleys 102, and the side surfaces 103 adjacent to each other face each other.

[0004]

A conventional bellows 100 having such a structure, when contracted in the axial direction and fully compressed, as shown in FIG.
Alternatively, the opposing surfaces of the valleys 102 come into surface contact with each other,
One or the valleys 102 adhere to each other. However, the bellows 100 is finished to a very smooth surface so that the surface roughness is extremely small.
Since the space 104 between the ridges 101 and the valleys 10 is in an airtight state and a negative pressure state,
The respective opposing surfaces of the two are not easily separated from each other. This adsorption phenomenon tends to occur particularly on the inner surface side that comes into contact with the transfer liquid. And when such an adsorption phenomenon occurs,
Since the contracted bellows 100 is difficult to expand, it is not possible to repeat a smooth expansion and contraction operation.

In order to prevent such an adsorption phenomenon from occurring, in the prior art, measures have been taken such as providing a stopper mechanism inside the bellows to restrict the movement of the bellows so that the bellows is not fully compressed. Providing such a stopper mechanism separately is not advantageous because the structure of the device using the bellows becomes complicated and the capacity of the bellows is reduced, so that the size of the bellows is increased. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a bellows having a relatively simple structure capable of preventing an adsorption phenomenon from occurring and a fluid device using the same. And

[0006]

In order to achieve the above-mentioned object, a bellows according to the present invention is a bellows made of synthetic resin which is formed of alternately formed peaks and valleys and which can be expanded and contracted in the axial direction. At least one of the opposing surfaces of the adjacent ridges and valleys is formed with a sneaking portion that prevents the ridges and valleys from being attracted to each other in a state of being fully compressed in the axial direction. (Claim 1). According to the bellows configured as described above, even when the bellows is fully compressed, the slack portion can prevent the peak portions and the valley portions from being attracted to each other.

[0007] The slack portion may be formed over the entire circumference of the opposing surfaces of the ridges and valleys adjacent to each other (claim 2). In this case, an adsorption phenomenon occurs. Can be more reliably prevented, and the slack portion can be easily formed by turning or the like.

[0008] The bellows may be formed such that a reinforcing portion protruding in a bellows radial direction is formed at each of a peak portion and a valley portion, and the slack portion is formed on both sides of the reinforcing portion. Item 3), in this case, the strength of the peaks and valleys can be increased by the reinforcing portions.

In the bellows according to the third aspect, the minimum thickness B in the bellows radial direction including the reinforcing portions of the peaks and the valleys, the thickness H of the reinforcing portions in the bellows axial direction, It is preferable that the thickness A of the side portion between the valley portion and the distance C between the opposing surfaces of the adjacent side portions are set so as to satisfy the conditions of A <B and C <H <2A + C. (Claim 4). In this case, since the thickness B of the reinforcing portion in the radial direction of the bellows is greater than the thickness A of the side surface portion, the side surface portion is easily bent when the bellows extends in the axial direction. For this reason, the stress generated on the inner peripheral surface of the peak and the outer peripheral surface of the valley,
Due to the bending of the side portions, the stress is dispersed or absorbed from the inner peripheral surface of the peak portion and the outer peripheral surface of the valley portion to each side portion connected to them, thereby avoiding local concentration of stress. Damage is prevented as much as possible. In addition, since the thickness B of the reinforcing portion in the bellows radial direction is larger than the interval C between the opposing surfaces of the adjacent side portions, the strength of the peak portion and the valley portion can be more effectively increased.

[0010] The slack portion may be locally formed on the opposing surfaces of the ridges and valleys adjacent to each other (claim 5). In this case as well, an adsorption phenomenon occurs. Can be reliably prevented. The synthetic resin as a material of the bellows is preferably a fluororesin (claim 6), and in this case, a mechanically, chemically and electrically stable bellows can be obtained. In particular, when a polytetrafluoroethylene resin is used as the fluororesin, a resin having excellent heat resistance and chemical resistance and having a high degree of cleanness that does not cause metal elution can be obtained.

According to a first aspect of the present invention, there is provided a fluid device including a pump diaphragm for taking in a transfer liquid from an inflow path and flowing out to an outflow path, wherein the pump diaphragm is the pump.
And a bellows according to any one of claims 6 to 6 (claim 7). In this case,
Since the occurrence of the adsorption phenomenon can be avoided only by the bellows, it is not necessary to particularly provide a mechanism for restricting the total compression of the bellows in the fluid device.

A fluid device according to the present invention is a fluid device having a pulsation damping diaphragm for taking in a transfer liquid from a pump from an inflow channel, temporarily storing the fluid, and then flowing the fluid to an outflow channel, wherein the pulsation damping diaphragm includes: A bellows according to any one of claims 1 to 6 is provided (claim 8). Also in this case, since the occurrence of the adsorption phenomenon can be avoided only by the bellows, it is not necessary to particularly provide a mechanism for restricting the entire compression of the bellows in the fluid device.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, and features thereof will be described in more detail. FIG. 1 is a longitudinal sectional view showing an entire pump device provided with a bellows pump as a fluid device and a pulsation damping device according to an embodiment of the present invention. In this pump device, a bellows pump 4 and a pulsation damping device 5 are coaxially arranged so as to face each other across a partition wall 1. In the partition wall 1, an inflow path 2 and an outflow path 3 of the transfer liquid are respectively formed, and a communication path 21 for communicating the bellows pump 4 and the pulsation damping device 5 is formed.

The bellows pump 4 has a bottomed cylindrical pump casing 6 attached to one of the side walls of the partition wall 1. The pump casing 6 extends and contracts in the pump casing 6 along its axial direction. A bellows 7 as a partition is provided. The opening peripheral portion 7a of the bellows 7
An annular fixing plate 8 is pressed and fixed to one of the side walls of the partition wall 1 in an air-tight manner.
Of the pump action chamber 9 located in the bellows 7
a and a pump operating chamber 9b located outside the bellows 7 in a sealed manner.

The bellows 7 is made of a fluororesin, in particular, polytetrafluoroethylene (PTFE) in this embodiment.
And is formed by cutting the PTFE cylindrical member with a lathe using a stick bite, a knife cutter, or the like. The shape of the bellows 7 is, as shown in FIGS.
a and a closed end portion 7b, a bellows-like shape in which ridge portions 71 and valley portions 72 are alternately provided, and between the ridge portions 71 and the valley portions 72. Is provided with a disk-shaped side surface portion 73 continuously. The bellows 7 has cut-off portions 74 and 75 formed on both sides of the opposing surfaces of the peak portions 71 and the valley portions 72 which are adjacent to each other, so as to prevent suction. I have. As a result, as shown in FIG. 5, when the bellows 7 is fully compressed in the axial direction,
The ridges 71 and the valleys 72 at the periphery of the area 75 can be in line contact with each other without surface contact, and as a result, the contact area between them can be reduced. No longer occurs.

In the bellows pump 4 having the structure shown in FIG. 1, a suction port 15a and a discharge port 15b for the transfer liquid are opened in a pump action chamber 9a defined by the bellows 7, respectively. The discharge port 15 b communicates with the inflow path 2, and the discharge port 15 b communicates with the outflow path 3 via the communication path 21. In the middle of the inflow passage 2 and the outflow passage 3, there are provided fluorine resin spring check valves 16a and 16b which open and close alternately with the expansion and contraction of the bellows 7, respectively.

Further, a connecting member 10 is fixed to the closed end portion 7b of the bellows 7 by using a bolt 31, and this connecting member 10 connects the center of the bottom wall 6a of the pump casing 6 from inside the pump working chamber 9b. The piston 11 penetrates and projects outward, and the piston 11 is fixed to the projecting portion. The piston 11 is slidably fitted in a cylinder 12 fixed to a bottom wall 6 a of the pump casing 6, and each air hole formed in the cylinder 12 and the bottom wall 6 a of the pump casing 6. A driving means for driving the bellows 7 to expand and contract by alternately supplying pressurized air from an air compressor (not shown) to the internal space surrounded by the cylinder 12 and the piston 11 and the inside of the pump operating chamber 9b through 13a and 13b. An air cylinder 14 is configured.

The air cylinder 14 has a proximity sensor 25
a and 25b are attached, while the sensor sensing plate 26 is attached to the piston 11 and the piston 1
The sensor sensing plate 26 is moved to the proximity sensor 25
By alternately approaching to a and 25b, the supply path of the pressurized air supplied from the air compressor is automatically switched between the inside of the cylinder 12 and the inside of the pump working chamber 9b.

On the other hand, in FIG. 1, the pulsation damping device 5
A bottomed cylindrical casing 17 is provided on the other side wall of the partition wall 1.
A bellows 18 is formed in the casing 17 as a pulsation damping partition which expands and contracts in the axial direction by cutting using a cutting tool or a knife made of PTFE similarly to the bellows 7. Is arranged. Then, the opening peripheral portion 18 a of the bellows 18 is pressed and fixed to the other side surface of the partition wall 1 in an airtight manner by the annular fixing plate 19, so that the inner space of the casing 17 is located in the bellows 18. And an air chamber 20b located outside the bellows 18 in a sealed state.

The bellows 18 is a bellows pump 4
Has basically the same configuration as the bellows 7 used in the above. That is, as shown in FIGS. 2 to 5, the bellows 18 also has an opening peripheral edge 18a and a closed end 18a.
b at the bellows-like trunk portion 18c between
And valleys 182 are provided alternately, and a side surface portion 183 is provided between the two, and a bellows shape is provided. The entire circumference of the opposing surfaces of the mutually adjacent peaks 181 and valleys 182 Over, the squeezed portion 18 for preventing adsorption
4, 185 are formed, and when the bellows 18 is fully compressed in the axial direction, the peaks 181 and the valleys 182 are brought into line contact with each other so that their contact area is reduced.

Further, in the pulsation damping device 5,
One end of the communication passage 21 is opened in the liquid chamber 20 a partitioned by the bellows 18 and communicates with the outflow passage 3.
A stopper wall 17b is provided at a position facing the closed end portion 18b of the bellows 18 of the casing 17 at a predetermined interval to restrict excessive extension of the bellows 18 that may occur in an unexpected situation.
Is provided. The bottom wall 17a of the casing 17 located outside the stopper wall 17b has an opening 1
7c is formed, and an automatic air supply / exhaust adjusting means 23 for adjusting the sealing pressure inside the air chamber 20b through the opening 17c is detachably attached by a bolt 24 or the like.

The automatic air supply / exhaust adjusting means 23 is
When the capacity of the liquid chamber 20a increases beyond the predetermined range, air is sucked into the air chamber 20b to increase the sealing pressure, and when the capacity of the liquid chamber 20a decreases beyond the predetermined range, the air is exhausted from the air chamber 20b. The sealing pressure is configured to be lowered, and the fluid pressure in the fluid chamber 20a and the air pressure in the air chamber 20b are balanced to prevent the bellows 18 from being excessively deformed. The automatic air supply / exhaust adjusting means 23
Valve push rod 3 for opening and closing the intake valve (not shown) provided for
0 and a valve puller 27 for opening and closing an exhaust valve (not shown)
The slider 28 attached to the tip of the air chamber 2 passes through the through hole 17d formed in the stopper wall 17b, respectively.
The slider 28 is always urged toward the bellows 18 by a spring 29.

Next, the operation of each of the bellows pump 4 and the pulsation damping device 5 of the pump device shown in FIG. 1 and the operation of the bellows 7 and 18 provided in these devices 4 and 5 will be described. First, with respect to the bellows pump 4, when pressurized air supplied from a compressor (not shown) or the like is supplied to the internal space surrounded by the cylinder 12 and the piston 11 of the air cylinder 14 through the air hole 13b, the bellows 7 The check valve 16a on the suction port 15a side is opened, and the transfer liquid from the inflow passage 2 is sucked into the pump action chamber 9a via the check valve 16a. You.
On the other hand, when the pressurized air is supplied into the pump working chamber 9a through the air hole 13a, the bellows 7 is contracted in the y direction in FIG. 1, and accordingly, the check valve 16b on the discharge port 15b side is opened, The transfer liquid sucked into the pump action chamber 9a is discharged from the check valve 16b to the communication passage 21 side. As described above, when the bellows 7 is expanded and contracted by the air cylinder 14, the check valves 16a and 16b in the pump action chamber 9a are provided.
Are alternately opened and closed, and the operation of sucking the transfer liquid from the inflow passage 2 into the pump action chamber 9a and the operation of discharging the transfer liquid from the inside of the pump action chamber 9a to the outflow passage 3 are repeated to perform a predetermined pump action. Is

Here, as shown in FIGS. 2 to 4, the bellows 7 have peak portions adjacent to each other at a bellows-shaped body portion 7c located between the opening peripheral portion 7a and the closed end portion 7b. Since the slack portions 74 and 75 are respectively formed on the opposing surfaces of the 71 and the valley portions 72, as shown in FIG. 5, even if the bellows 7 is fully compressed in the axial direction, each of the slack portions 74 is formed. , 75 can be brought into line contact with each other between the peaks 71 and the valleys 72, and the contact area between them becomes extremely small. For this reason,
Even if the ridges 71 and the valleys 72 come into contact with each other, the phenomenon that the internal space 76 surrounded by the side surfaces 73 becomes airtight and adheres to each other does not occur. Therefore, even if the bellows 7 is fully compressed in the axial direction, the bellows 7 can be easily restored to the original shape if the pressing force by the air cylinder 14 is eliminated. As described above, since the occurrence of the adsorption phenomenon can be avoided only by the processing shape of the bellows 7, the smooth operation of the bellows 7 can be always ensured without providing a mechanism for preventing the bellows pump 4 from being fully compressed. Thus, the life of the bellows 7 can be extended, and the reliability of the bellows pump 4 can be enhanced.

The transfer liquid discharged from the discharge port 15b of the bellows pump 4 becomes a pulsating flow due to the reciprocating operation of the bellows pump 4, and the liquid chamber inside the bellows 18 of the pulsation damping device 5 through the communication passage 21. After being sent into the inside 20a and temporarily stored therein, it is discharged from the outflow channel 3 to the outside. At this time, when the discharge pressure of the transfer liquid tends to increase, the bellows 18 of the pulsation damping device 5 expands to increase the capacity of the liquid chamber 20a to absorb the discharge pressure. At this time, the liquid chamber 2
The volume of the transfer liquid flowing out of the bellows pump 4a
Is smaller than the amount of liquid discharged from the nozzle. In this state, when the discharge pressure of the transfer liquid starts to decrease, the pressure of the transfer liquid becomes lower than the sealing pressure in the air chamber 20b compressed by the expansion of the bellows 18, so that the bellows 18 contracts and the liquid chamber Reduce the capacity of 20a. At this time, the liquid amount of the transfer liquid flowing out of the liquid chamber 20a is larger than the liquid amount discharged from the bellows pump 4. The pulsation of the transfer liquid is attenuated by the repetitive operation of the change in the capacity of the liquid chamber 20a accompanying the expansion and contraction of the bellows 18, and the transfer liquid flows out smoothly continuously.

Here, the bellows 18 forming the pulsation damping device 5 are similar to the bellows 7 forming the bellows pump 4, and are formed between adjacent peaks 181 and valleys 182 in a bellows-shaped body portion 18 c. Since the slack portions 184 and 185 are formed on the respective opposing surfaces, as shown in FIG. 5, even when the bellows 18 is fully compressed in the axial direction, the peak portions 181 around the slack portions 184 and 185 are formed. The contact area between the valleys 182 and between the valleys 182 becomes extremely small. Therefore, even when the peaks 181 and the valleys 182 come into contact with each other, the phenomenon that the internal spaces 186 surrounded by the side surfaces 183 become airtight and are not attracted to each other does not occur, and the smooth expansion and contraction operation is always repeated. . As described above, since the adsorption phenomenon can be avoided only by the processed shape of the bellows 18, a smooth operation can always be ensured without particularly providing the pulsation damping device 5 with a mechanism for preventing full compression. As a result, the life of the pulsation damping device 5 can be improved.

In the above operation, the fluctuation of the discharge pressure of the bellows pump 4 causes the liquid chamber 20 of the pulsation damping device 5 to change.
When the capacity of the bellows increases beyond a predetermined range, the bellows 18
Of the automatic supply / exhaust adjusting means 23 and further pushes the valve push rod 30 to the left, so that an intake valve (not shown) is opened to allow intake into the air chamber 20b. As a result, the sealing pressure is increased, and excessive elongation and deformation of the bellows 18 is suppressed, so that the capacity in the liquid chamber 20a is prevented from being excessively increased. On the other hand, when the capacity of the liquid chamber 20a decreases beyond the predetermined range, the slider 28 engages with the tip of the valve pulling rod 27 and pushes the valve pulling rod 27 rightward by the spring 29, so that the exhaust valve (not shown) opens. Then, the gas is exhausted into the air chamber 20b to lower the sealing pressure, and excessive contraction and deformation of the bellows 18 are suppressed, so that the capacity of the liquid chamber 20a is prevented from being excessively reduced. In this way, regardless of the fluctuation of the discharge pressure of the bellows pump 4, the amount of expansion and contraction of the bellows 18 is regulated within a certain range, and the pulsation width can be suppressed to a small value.

In the above embodiment, FIG.
As shown in FIG. 5, each of the bellows 7, 18 has a peak portion 71, which is adjacent to each other in a bellows-like trunk portion 7c.
The facing surfaces of the 181 and the valleys 72 and 182 are cut out over the entire circumference to form the suction-preventing slidable portions 74 and 75, respectively, as shown in FIG. A part of the opposing surface of each of the valleys 72, 182 and the valleys 72, 182 may be partially cut out to form the slimened parts 74, 75, 184, 185 locally. That is, as shown in FIG. 7A, the slack portions 74, 75, 184, and 185 are
It is formed at only one location on each of the opposing surfaces of one and the valleys 72 and 182, or is formed radially at six equally spaced positions as shown in FIG. Like 4
It may be formed at an equal position, or may be formed at three equal positions as shown in FIG.
5, 184, 185 may have a shape slightly bulged in the radial direction as shown in FIG.

Further, as shown in FIG.
Reinforcing portions 71a, 72a, 1 protruding in the bellows radial direction are respectively provided on the peak portions 71, 181 and the valley portions 72, 182 of the eighteenth embodiment.
81a and 182a may be formed, and the recesses formed on both sides of the reinforcing portion may be used as the burrs 74, 75, 184 and 185. In this case, the peaks 71, 181
And the reinforcing portions 71a, 72a,
Minimum thickness B in the bellows radial direction including 181a and 182a
The thickness H of the reinforcing portions 71a, 72a, 181a, 182a in the bellows axial direction, the peak portions 71, 181 and the valley portions 72,
The thickness A of the side surface portions 73 and 183 between the side surfaces 182 and the distance (stick width) C between the opposing surfaces of the adjacent side surface portions 73 and 183 satisfy the conditions of A <B and C <H <2A + C. Set as follows.

According to this embodiment, it is possible to prevent the above-mentioned slush portions 74, 75, 184 and 185 from causing an adsorption phenomenon. The reinforcing portion 71
a, 72a, 181a, 182a Bellows radial thickness B
However, since the thickness is larger than the thickness A of the side surface portion, the side surface portions 73 and 183 are easily bent when the bellows 7 extends in the axial direction. Therefore, the peaks 71 and 181 and the valleys 72 and 182
And the peaks 71 and 18 can be dispersed.
The stress concentration occurring on the inner peripheral surface 1 and the outer peripheral surfaces of the valleys 72 and 182 is alleviated, so that cracks can be prevented from being generated on these peripheral surfaces. Therefore, the durability of the bellows 7, 18 can be ensured. In particular, the reinforcing portions 71a, 72a, 18
Since the thickness B in the bellows radial direction of the bellows 1a, 182a is larger than the distance C between the opposing surfaces of the adjacent side surfaces 73, 183, each of the peaks 71, 181 and the valleys 72, 182 is replaced with the reinforcing portion 71a. , 72a, 181a and 182a can be reinforced more effectively.

FIG. 8 is a longitudinal sectional view showing the entirety of a pulsation damping device according to another embodiment of the present invention, and portions corresponding to those shown in FIG. 1 are denoted by the same reference numerals. . In the embodiment shown in FIG. 8, the pulsation damping device 5 shown in FIG.
Are formed independently of the bellows pump 4, and the casing 17 is formed by fixing an upper wall member 33 and a lower wall member 34 to upper and lower ends of a cylindrical peripheral wall member 32, respectively. A bellows 18 is disposed in the casing 17 as a pulsation damping partition wall that expands and contracts along its axial direction.

The opening edge 1 of the bellows 18
8a is air-tightly pressed and fixed to the other side surface of the partition wall 1 by the annular fixing plate 19, so that the casing 17
Is hermetically partitioned into a liquid chamber 20a located inside the bellows 18 and an air chamber 20b located outside the bellows 18. The lower wall member 34 has an inflow passage 2 for the transfer liquid.
And an outflow passage 3 are formed so that the two 2 and 3 communicate with the liquid chamber 20a.
3 are provided. The bellows 18 has basically the same configuration as that used in the pulsation damping device 5 shown in FIG. The configuration of the automatic air supply / exhaust adjusting means 23 is also the same as that of the pulsation damping device 5 shown in FIG. 1, and therefore, detailed description of the operation thereof will be omitted.

FIG. 9 is a longitudinal sectional view showing the entire bellows pump according to still another embodiment of the present invention. The bellows pump of the embodiment shown in FIG. 9 has a pair of left and right pump portions arranged symmetrically, and a large transfer amount can be obtained by operating the respective pump portions complementarily. That is, in the bellows pump of this embodiment, the pump casing 40 is formed by fixing the side wall members 42 and 43 to the left and right ends of the cylindrical peripheral wall member 41, respectively.
A pair of bellows 45, 46 are arranged symmetrically with respect to the left and right. In this case, the bellows 45 and 46 are as shown in FIG.
It has basically the same configuration as the bellows 7 as a pump diaphragm used in the bellows pump 4 shown in FIG. The bellows 45, 46 have their opening peripheral edges pressed and fixed airtight to the side walls of the partition wall 44 by the annular fixing plates 48, 49, respectively.
Pressure receiving plates 51 and 52 are attached to the closed end of the.

The partition wall 44 has an inflow passage 54 for the transfer liquid.
Check valves 56a, 56 which open and close alternately with the expansion and contraction of the bellows 45, 46, respectively, in the middle of the inflow path 54 and the outflow path 55.
b, 57a and 57b are provided. Further, the left and right side wall members 42 and 43 of the casing 40 are provided with air holes 42a and 43a for supplying pressurized air supplied from a compressor or the like (not shown) into the casing 40 and the casing 4.
Air holes 42b and 43b for exhausting from 0 are respectively formed.

Accordingly, in the bellows pump having this configuration, pressurized air supplied from a compressor (not shown) or the like is alternately supplied from the air holes 42a and 43a to alternately expand and contract the left and right bellows 45 and 46. And the check valve 5 from the inflow path 2 by the bellows 46 on the right side, for example.
When the transfer liquid is sucked in through 7b, the transfer liquid stored in the bellows 45 on the left side flows out of the outflow passage 55 through the check valve 56a. When the transfer fluid is sucked from the inflow path 2 through the check valve 56b by the left bellows 45, the transfer fluid stored in the inside thereof is checked by the right bellows 46.
Through the outflow channel 55. In this way, the left and right bellows 45 and 46 are alternately expanded and contracted, so that the suction of the transfer liquid from the outflow path 54 and the discharge to the outflow path 3 are repeated, and a predetermined pump action is performed.

In each of the above embodiments,
The recesses 74, 184 are provided on the respective opposing surfaces of the adjacent peaks 71, 181 and the adjacent valleys 7 are provided.
2, 182 are provided on the opposing surfaces, respectively.
185 may be provided only on one side of the facing surface.

[0037]

As described above, according to the bellows of the first aspect, even when the bellows is fully compressed in the axial direction, it is possible to prevent the ridges and the valleys from being attracted to each other by the slack portion. Therefore, the bellows can always be smoothly expanded and contracted.

According to the bellows of the second aspect, since the sunk portion is formed over the entire circumference of the opposing surfaces of the adjacent ridges and valleys, the occurrence of the adsorption phenomenon is further reduced. It is possible to surely prevent the swelling, and it is possible to easily form the slack portion.

According to the bellows according to the third aspect, the strength of the peaks and valleys can be increased by the reinforcing portions.
The durability of the bellows can be improved. Claim 4
According to the bellows described, it is possible to alleviate the stress concentration generated in the peaks and the valleys when the bellows extends in the axial direction, and to more effectively increase the strength of the peaks and the valleys. Therefore, the durability of the bellows can be further improved.

According to the bellows of the fifth aspect, it is possible to reliably prevent the adsorption phenomenon from occurring due to the locally formed squeezed portion. According to the bellows according to claim 6, since the material is a fluororesin, mechanical,
It exhibits chemically and electrically stable characteristics, and can extend the life of the bellows more effectively.

According to the fluid device of the seventh aspect, since the bellows can always be smoothly expanded and contracted, the reliability of the fluid device can be enhanced. According to the fluid device of the eighth aspect, since the bellows can always be smoothly expanded and contracted, the reliability of the fluid device can be enhanced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entire pump device provided with a bellows pump and a pulsation damping device according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a part of a bellows used for each of a bellows pump and a pulsation damping device.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a longitudinal sectional view showing a further enlarged main part of the bellows shown in FIGS. 1 and 2;

5 is a longitudinal sectional view showing a state where the bellows shown in FIG. 4 is fully compressed.

FIG. 6 is a plan sectional view showing a bellows according to another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a bellows according to another embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of the pulsation damping device according to the embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of the bellows pump according to the embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a conventional bellows.

11 is a longitudinal sectional view showing a state where the bellows shown in FIG. 10 is fully compressed.

[Explanation of symbols]

 Reference Signs List 2 inflow path 3 outflow path 4 bellows pump 5 pulsation damping device 7 bellows (pump diaphragm) 71 mountain part 72 valley part 73 side surface part 74, 75 sunk part 14 air cylinder (drive means) 18 bellows (pulsation damping diaphragm) 181 Mountain part 182 Valley part 183 Side part 184,185 Slack part 45,46 Bellows

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16J 3/04 F04B 43/08 F16D 3/84 F16J 15/52

Claims (8)

(57) [Claims] 1. A bellows made of a synthetic resin, which is formed of alternately formed peaks and valleys and which can be expanded and contracted in the axial direction, has at least one of opposing surfaces of the ridges and valleys adjacent to each other. A bellows formed with a slack portion for preventing the peak portions and the valley portions from being attracted to each other in a state of being fully compressed in the axial direction. 2. The bellows according to claim 1, wherein the squeezed portion is formed over the entire periphery of the opposing surfaces of the adjacent ridges and valleys. 3. The bellows according to claim 2, wherein a reinforcing portion protruding in a bellows radial direction is formed at each of the crests and the valleys, and the recesses are formed on both sides of the reinforcing portion. 4. A method according to claim 1, wherein a minimum thickness B in the bellows radial direction including the reinforcing portions of the peaks and valleys, a thickness H of the reinforcing portions in the axial direction of the bellows, and a distance between the peaks and the valleys. Side wall thickness A
And the distance C between the opposing surfaces of the adjacent side portions is A <B
4. The bellows according to claim 3, wherein the bellows are set so as to satisfy a condition of C <H <2A + C. 5. The bellows according to claim 1, wherein the sunk portion is locally formed on each of opposing surfaces of the ridges and valleys adjacent to each other. 6. The method according to claim 1, wherein said synthetic resin is a fluororesin.
A bellows according to claim 5. 7. A fluid device having a pump diaphragm for taking in a transfer liquid from an inflow channel and flowing out to an outflow channel, wherein the pump diaphragm is constituted by the bellows according to any one of claims 1 to 6. Fluid equipment characterized by being done. 8. A fluid device provided with a pulsation damping diaphragm for taking in a transfer liquid from a pump from an inflow passage, temporarily storing the liquid, and then flowing the liquid to an outflow passage. A fluid device comprising the bellows according to claim 6.