JP3803070B2 - Fluid pressure cylinder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid pressure cylinder that linearly reciprocates a piston rod by fluid pressure such as compressed air.
[0002]
[Prior art]
BACKGROUND ART A fluid pressure cylinder that converts fluid energy such as compressed air into linear motion of a piston rod has a cylinder tube on which a piston is reciprocally mounted in an axial direction. End covers are provided at both ends of the cylinder tube, and the cylinder body is formed by the cylinder tube and the end cover. A piston rod is attached to the piston so as to protrude from the end of the cylinder body. By supplying fluid pressure to a pressure chamber formed in the cylinder body, the piston and the piston rod are integrally driven in the axial direction. .
[0003]
Fluid pressure cylinders are classified into double-acting types and single-acting types based on structural differences. The double-acting fluid pressure cylinder has pressure chambers formed on both sides of the piston, and is a type in which the piston rod is moved forward and backward by fluid pressure. The cylinder has a pressure chamber only on one side of the piston, and is a type of cylinder in which either forward movement or backward movement is performed by fluid pressure and the other is performed by an external force such as a spring force. The type in which the piston rod protrudes from one end of the cylinder body is called a single rod, and the type in which the piston rod protrudes from both ends is called a double rod. There are cases where compressed air is used as fluid energy for driving the piston and liquids such as hydraulic oil are used.
[0004]
In any type of fluid pressure cylinder, conventionally, the piston rod is fixed to the piston, and the piston rod is linearly reciprocated integrally with the piston. Since the piston moves while contacting the inner peripheral surface of the cylinder body, in order to ensure airtightness between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder tube, a seal such as an O-ring or packing is provided on the outer periphery of the piston. A member is mounted. The basic structure of such a fluid pressure cylinder is described in, for example, pages 486 to 488 of Oil-Air Handbook issued by Ohm Co., Ltd. (issued February 25, 1989).
[0005]
[Problems to be solved by the invention]
In such a fluid pressure cylinder, since the seal member is in sliding contact with the inner peripheral surface of the cylinder tube when the piston moves, sliding resistance is applied to the piston. For this reason, the output of the piston rod determined by the pressure receiving area of the piston on which the fluid pressure in the pressure chamber acts and the fluid pressure will be affected by the sliding resistance, and the stability of the output of the piston rod will be reduced. . For this reason, when applying pressure to the object with the piston rod after moving the piston rod forward, the pressure becomes unstable due to the sliding resistance of the seal member, and a constant pressure can be applied to the object. Disappear. In particular, in a pneumatic cylinder that operates a piston rod with a pressure lower than that of a hydraulic cylinder, the influence of the sliding resistance of the seal member acts greatly, and the applied pressure becomes unstable.
[0006]
Also, in a fluid pressure cylinder that is mounted so that the piston rod reciprocates in the vertical direction, gravity acts on the piston rod and the piston, so that, for example, the pressure applied to the object downward via the piston rod is reduced. In addition to the thrust set by the fluid pressure, gravity is applied. For this reason, it is difficult not only to obtain a high-precision pressure, but it has also been impossible to set a pressure smaller than the gravity acting on the piston and piston rod.
[0007]
An object of the present invention is to make it possible to apply a constant pressing force to an object with high accuracy by a piston rod driven by fluid pressure.
[0008]
[Means for Solving the Problems]
The fluid pressure cylinder of the present invention is provided on the cylinder body. Between the forward limit position and the reverse limit position Built in to reciprocate in the axial direction And a forward pressure chamber in which forward fluid pressure is applied in the cylinder body. A piston, and is supported by the piston so as to be reciprocally movable in an axial direction; a pressurizing chamber is defined in the piston; one A piston rod protruding from the end, and a diaphragm for balancing mounted between the piston and the piston rod; A closing diaphragm mounted between the piston and the piston rod, defining a balance pressure chamber by the balancing diaphragm and applying a fluid pressure in a backward direction to the piston rod; and communicating with the balance pressure chamber And a fluid supply passage The piston rod is pushed in the forward direction by the fluid pressure in the pressurizing chamber while the fluid pressure in the balance pressure chamber is applied to the piston rod in the backward direction.
[0010]
The fluid pressure cylinder of the present invention includes a pressurizing diaphragm that is mounted between the piston and the piston rod and defines the pressurizing chamber.
[0011]
The fluid pressure cylinder of the present invention is a single-acting cylinder that applies an external force in a backward direction to the piston.
[0012]
The fluid pressure cylinder of the present invention is a double-acting cylinder in which a pressure chamber for retreat for applying a fluid pressure in a retreat direction to the piston is provided in the cylinder body.
[0013]
In the fluid pressure cylinder of the present invention, the piston is formed by a main piston member through which the piston rod passes and a sub piston member attached to the main piston member and restricting a movement stroke of the piston rod relative to the main piston member. It is characterized by that.
[0014]
The fluid pressure cylinder of the present invention is characterized in that a pressure rod having a fluid supply passage communicating with the balance pressure chamber is projected from the other end of the cylinder body and attached to the sub piston member.
[0015]
The fluid pressure cylinder according to the present invention is characterized in that a fluid supply passage communicating with the pressurizing chamber is formed in the pressure rod.
[0016]
The fluid pressure cylinder of the present invention is characterized in that a communication hole for communicating the pressurizing chamber and the forward pressure chamber is formed in the sub piston member.
[0017]
The fluid pressure cylinder according to the present invention is characterized in that a fluid supply passage communicating with the balance pressure chamber is formed in the piston rod.
[0018]
The fluid pressure cylinder of the present invention is characterized in that a fluid supply passage communicating with the pressurizing chamber is formed in the piston rod.
[0019]
The fluid pressure cylinder of the present invention is characterized in that a rotation stopper is provided between the piston and the piston rod.
[0020]
According to the present invention, by supplying fluid pressure to the balance pressure chamber defined by the balance diaphragm, it is possible to apply thrust against the gravity in the backward direction to the piston rod, which acts on the piston rod. Gravity can be offset. Moreover, the piston rod can be pushed in the forward direction by supplying fluid pressure to the pressurizing chamber defined by the piston and the piston rod. Because of these, after moving the piston rod using the piston, the piston rod can be pressed with high accuracy and no fluctuation without being affected by gravity acting on the piston rod or sliding resistance of the piston. Can do.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 2 are longitudinal sectional views showing a fluid pressure cylinder 10a according to an embodiment of the present invention. FIG. 1 shows a state in which the piston rod 11 is retracted or raised, and FIG. That is, it shows a lowered state. 3 is a transverse sectional view taken along line AA in FIG. 1, and FIG. 4 is an enlarged sectional view showing a part of FIG.
[0022]
The fluid pressure cylinder 10a is a single-acting pneumatic cylinder that uses compressed air as a working fluid. The fluid pressure cylinder 10a is vertically attached to various devices (not shown), and an object W made of a workpiece, jig or tool provided at the tip of the piston rod 11 protruding from the cylinder body 12 is composed of various devices or equipment. This is applied to press the object R with a predetermined pressure.
[0023]
As shown in FIG. 1, a cylinder assembly, that is, a cylinder body 12 is formed by a cylinder tube 13 and end covers 14 a and 14 b provided at both ends of the cylinder tube 13. In the illustrated fluid pressure cylinder 10a, for convenience of drawing, the cylinder tube 13 and end covers 14a and 14b at both ends are shown as a single unit. The main body 12 may be assembled, and either one of the two end covers 14 a and 14 b may be formed integrally with the cylinder tube 13. Further, as shown in FIG. 3, the cylinder tube 13 is formed of a cylindrical member having a uniform thickness in the circumferential direction as a whole. However, the cross-sectional shape of the outer peripheral surface is substantially rectangular. Alternatively, the cylinder tube 13 may be formed using a member.
[0024]
A piston 15 is incorporated in the cylinder body 12 so as to be capable of reciprocating in the axial direction. The piston 15 has a main piston member 16 and a sub piston member 17, which are coupled via a screw coupling portion 18. The main piston member 16 has an end plate portion 16a, a cylindrical portion 16b, and an annular portion 16c, which are integrally formed. On the other hand, the auxiliary piston member 17 has an end plate portion 17a and an annular portion 17b integrated therewith, and the screw coupling portion 18 is constituted by a female screw and a male screw formed in each of the annular portions 16c and 17b. ing. However, both the main piston member 16 and the sub piston member 17 may be connected by caulking without being screw-coupled, or may be connected using a screw member.
[0025]
Two sleeves 20 and 21 are inserted in series in the cylindrical portion 16 b of the main piston member 16. The inner peripheral surfaces of the sleeves 20 and 21 are smoothly cut, and a substantially cylindrical pressure receiving member 22 is incorporated in the sleeves 20 and 21 so as to reciprocate in the axial direction. A rod member 24 is attached to the lower end surface of the pressure receiving member 22 via a rod collar 23 having a flange portion, and the piston rod 11 is constituted by the pressure receiving member 22, the rod collar 23, and the rod member 24. The piston rod 11 is assembled so as to protrude from the cylinder body 12 through the through holes 25 and 26 respectively formed in the end plate portion 16 a of the main piston member 16 and the end cover 14 b of the cylinder body 12. . A large-diameter head portion 27 is integrally provided at the base end of the rod member 24, and the lower end surface of the head portion 27 and the end plate portion 16a are in contact with each other, so that the downward movement of the piston rod 11 is restricted. . The end cover 14b is provided with a sliding bearing 28 for guiding the axial movement of the piston rod 11.
[0026]
FIG. 4 is an enlarged longitudinal sectional view showing a part of FIG. As shown in FIG. 4, three diaphragms 31 to 33 are mounted in the piston 15 to define each pressure chamber. The diaphragm is a thin film component formed by laminating a cloth layer made of polyester or the like and a rubber layer, and converts a pressure change into a position displacement by partitioning each pressure chamber having a different pressure. The diaphragm has disk-shaped center portions 31a to 33a and annular flange portions 31b to 33b, and the center portions 31a to 33a and the flange portions 31b to 33b are interposed via folded portions 31c to 33c. Cylindrical portions 31d to 33d having inner and outer double structures are provided. When the diaphragm is operated, the folding portions 31c to 33c roll, so that no sliding resistance is generated.
[0027]
The center portion 31 a of the balancing diaphragm 31 is mounted between the pressure receiving member 22 and the rod collar 23, and the flange portion 31 b is mounted between the two sleeves 20 and 21. The central portion 32 a of the closing diaphragm 32 is mounted between the rod collar 23 and the head portion 27 of the rod member 24, and the flange portion 32 b is mounted between the sleeve 21 and the main piston member 16. Thus, the balance pressure chamber 34 is defined by the balance diaphragms 31 and 32, and the sleeves 20 and 21 and the sub piston member 17 are supplied to supply fluid pressure to the balance pressure chamber 34. Fluid supply passages 35 to 37 communicating with the balance pressure chamber 34 are formed. Further, a pressure rod 39 protruding from a communication hole 38 formed in the end cover 14 a is provided at the upper end portion of the sub piston member 17, and pressure is supplied from the supply / discharge port 40 formed at the end portion of the pressure rod 39. Compressed air is supplied to the fluid supply passage 37 of the auxiliary piston member 17 through the fluid supply passage 41 of the rod 39.
[0028]
The balance pressure chamber 34 is defined by a blocking diaphragm 32 provided on the head portion 27 of the rod member 24 and a balance diaphragm 31 provided on the pressure receiving member 22 having a larger diameter than the head portion 27. Therefore, the effective pressure receiving area of the diaphragm 31 for balance is set larger than that of the diaphragm 32 for closing. Accordingly, when a pressure is supplied to the balance pressure chamber 34, a thrust obtained by multiplying the difference in effective pressure receiving area between the balance diaphragm 31 and the closing diaphragm 32 by the pressure in the balance pressure chamber 34 is applied upward. At this time, when the piston rod 11 is raised, the folded portions 31c and 32c of the balance and closing diaphragms 31 and 32 are both raised, and when the piston rod 11 is lowered, both the folded portions 31c and 32c are lowered. In this way, even when the piston rod 11 is operated, the volume change of the balance pressure chamber 34 is suppressed, and the pressure fluctuation of the fluid pressure P4 is also suppressed low, so that a stable thrust can be obtained from the balance pressure chamber 34. Become.
[0029]
Further, the central portion 33a of the pressurizing diaphragm 33 is mounted on the end face of the pressure receiving member 22, and the flange portion 33b is mounted between the sleeve 20 and the sub piston member 17, and the pressurizing diaphragm 33 and the sub piston member are mounted. 17 forms a pressurizing chamber 42. In order to supply pressure to the pressurizing chamber 42, a communication hole 44 communicating with the fluid supply passage 43 of the pressure rod 39 is formed in the auxiliary piston member 17, and a supply / discharge port 45 formed at the end of the pressure rod 39. Compressed air is supplied from the pressure chamber 42 to the pressurizing chamber 42. When pressure is supplied to the pressurizing chamber 42, a downward thrust is applied to the piston rod 11 through the pressure receiving member 22.
[0030]
In addition, as shown with a broken line in FIG. 4, bead is provided in the flange parts 31b-33b of the diaphragms 31-33 so that it may engage with the annular grooves 46-48 formed in the sleeve 20 and the main piston member 16, respectively. Anyway. Further, a retainer may be attached to the end portion of the pressure receiving member 22 so as to cover the central portion 33a of the diaphragm 33 for pressurization.
[0031]
The downward movement of the piston rod 11 accompanying the pressure supply to the pressurizing chamber 42 is regulated by the contact between the end plate portion 16a of the main piston member 16 and the head portion 27 of the rod member 24, and the upward movement of the piston rod 11 is performed. Is regulated by the contact between the end plate portion 17a of the sub piston member 17 and the pressure receiving member 22. For this reason, the piston rod 11 is movable in the axial direction with a predetermined stroke with respect to the piston 15. As shown in FIG. 4, even when the piston rod 11 is at the lowest position with respect to the piston 15, the folded portions 31 c to 33 c are formed in the three diaphragms 31 to 33. Further, when the piston rod 11 is raised and the pressure receiving member 22 and the sub piston member 17 come into contact with each other, the three pistons 31 to 33 are formed with the folded portions 31c to 33c so that the sub piston member 17 has the folded portions 31c to 33c. The end plate part 17a is set.
[0032]
Further, in order not to disturb the movement of the diaphragms 31 to 33, a bleed port, that is, a breathing hole 51 is opened to the outside through the rod member 24 between the diaphragms 31 and 33 for balance and pressurization. A breathing hole 52 is also formed in the end plate portion 16 a provided below the closing diaphragm 32.
[0033]
Seal members 53 and 54 that keep airtightness with the inner peripheral surface of the cylinder tube 13 are incorporated in the outer periphery of the piston 15, and the piston 15 with respect to the cylinder body 12 is interposed between the piston 15 and the end cover 14 a. A descending pressure chamber 55 for supplying a pressure for moving the pressure chamber in a descending direction is defined as a forward pressure chamber, and a supply / discharge port 56 communicating with the pressure chamber is formed in the end cover 14a.
[0034]
A spring chamber 57 is formed between the piston 15 and the end cover 14b, and a compression coil spring 58 for applying a spring force in the upward direction to the piston 15 is incorporated in the spring chamber 57. Therefore, when compressed air is supplied from the supply / discharge port 56, a downward thrust is applied to the piston 15, and the piston 15 moves in the downward direction together with the piston rod 11 against the spring force. The lower limit position of the piston 15 is regulated by a stopper surface 59 provided on the end cover 14b.
[0035]
On the other hand, when the compressed air is discharged from the supply / discharge port 56, the piston 15 is moved by the upward thrust applied by the compression coil spring 58. During these movements, a breathing hole 60 is formed in the cylinder tube 13 for allowing an air flow between the spring chamber 57 and the outside.
[0036]
The piston rod 11 is provided with a rotation stop key 61 that engages with a key groove formed in the main piston member 16 so that the piston rod 11 does not rotate with respect to the piston 15. However, if the cross-sectional shape of the rod member 24 is a quadrangle, the rotation stop key 61 is not necessary. The cross-sectional shape is not limited to a quadrangle, and any shape other than a circle such as a polygon or an ellipse may be used. It can be applied even if it exists.
[0037]
Hereinafter, the pressing operation of the object W against the object R performed using the fluid pressure cylinder 10a will be described. As shown in FIG. 1, when compressed air is supplied from the supply / discharge port 56 to the descending pressure chamber 55 in a state where the piston 15 is in the ascending limit position, the piston 15 is pushed down in the descending direction. At this time, a fluid pressure P3 corresponding to the pressure applied when the object W is pressed against the object R is supplied to the pressurizing chamber 42 from the supply / discharge port 45, and the balance pressure chamber 34 corresponds to the gravity acting on the piston rod 11. The fluid pressure P4 is supplied from the supply / discharge port 40. Accordingly, the piston 15 moves downward against the spring force while the piston rod 11 is disposed at the lower limit position, and the air in the spring chamber 57 is discharged from the breathing hole 60 to the outside.
[0038]
When the piston rod 11 moves downward as the piston 15 moves downward, as shown in FIG. 2, the object W comes into contact with the object R, so that the piston rod 11 stops moving downward. Continue to move down until touching. Due to the forward movement of only the piston 15, the head portion 27 of the rod member 24 moves away from the end plate portion 16 a, and the piston rod 11 moves relative to the piston 15 in the upward direction. Therefore, the piston rod output applied to the object W from the piston rod 11 is set by the product of the fluid pressure P3 in the pressurizing chamber 42 and the effective pressure receiving area of the pressurizing diaphragm 33, and the seal member 53 provided on the piston 15 is set. , 54 and the inner peripheral surface of the cylinder tube 13 do not affect the piston rod output.
[0039]
Further, the fluid pressure P4 supplied to the balance pressure chamber 34 gives the piston rod 11 an upward thrust against gravity. That is, thrust from the balance pressure chamber 34 is applied to the piston rod 11 that transmits the pressure applied from the pressurizing chamber 42 to the object W so as to cancel the gravity acting on the piston rod 11. Therefore, for example, even when pressing the object W by setting a small pressing force that is less than the gravity acting on the piston rod 11, the piston rod output can be set with high accuracy.
[0040]
The constant pressure is applied to the object W as described above when the gap S1 is generated above the pressure receiving member 22 and the gap S2 is generated below the head 27 as shown in FIG. That is, when the piston rod 11 is in a floating state, even if an error occurs in the lower limit position of the piston rod 11, if a floating state is ensured, a constant pressure is applied to the object W. . As described above, the pressure applied to the object W is set by the product of the fluid pressure P3 applied to the pressurizing diaphragm 33 and the effective pressure receiving area, and acts on the influence of the sliding resistance of the seal members 53 and 54 and on the piston rod 11. Since it is not affected by gravity, the applied pressure can be set with high accuracy. Further, even if a rotational force is applied to the piston rod 11 during floating, the rotation stop key 61 does not cause the piston 15 and the piston rod 11 to rotate relative to each other, and the diaphragms 31 to 33 are prevented from being damaged by twisting.
[0041]
Next, when the compressed air is discharged from the supply / exhaust port 56 after the pressurization operation of the object W on the object R is completed, first, the piston 15 is moved upward by the spring force. After the head portion 27 comes into contact with the end plate portion 16a by the subsequent ascending movement, the piston 15 moves up to the ascending limit position together with the piston rod 11.
[0042]
FIG. 5 is a longitudinal sectional view showing a fluid pressure cylinder 10b according to another embodiment of the present invention. In FIG. 5, the same members as those in the above-described embodiment are denoted by the same reference numerals. Yes. This fluid pressure cylinder 10b is obtained by changing the fluid pressure cylinder 10a shown in FIG. 1 to a double-acting type, and pressure chambers are defined on both sides of the piston 15. One pressure chamber is a reverse pressure chamber for the piston 15, that is, a rising pressure chamber 62, and the other pressure chamber is a descending pressure chamber 55. A supply / exhaust port 63 communicating with the ascending pressure chamber 62 is formed in the cylinder tube 13. When the piston 15 is moved up from the descending limit position to the ascending limit position, compressed air is supplied from the supply / exhaust port 63. The compressed air is discharged from the supply / discharge port 56. In order to prevent the air in the rising pressure chamber 62 from leaking outside, a seal member 64 is provided on the end cover 14b. And the breathing hole 60 of the cylinder tube 13 provided in the fluid pressure cylinder 10a is closed. Further, in order to prevent reversal that may occur in the folded portion 32 c of the closing diaphragm 32, the fluid pressure P <b> 2 supplied to the rising pressure chamber 62 is set smaller than the fluid pressure P <b> 4 supplied to the balance pressure chamber 34. Is done.
[0043]
When the piston 15 of the fluid pressure cylinder 10b is lowered, compressed air is discharged from the supply / discharge port 63 and compressed air is supplied from the supply / discharge port 56. When the piston 15 is raised, compressed air is supplied to the supply / discharge port 63. By discharging the compressed air from the supply / discharge port 56, it can be used in the same manner as the fluid pressure cylinder 10a described above.
[0044]
6 and 7 are longitudinal sectional views showing fluid pressure cylinders 10c and 10d according to still another embodiment of the present invention. In FIGS. 6 and 7, the members common to the members in the above-described embodiment are shown. Are given the same reference numerals. The fluid pressure cylinders 10c and 10d are formed by dividing the pressure chamber 42 defined by the pressure diaphragm 33 in the fluid pressure cylinders 10a and 10b without using the pressure diaphragm 33 and the sub piston. A partition is formed using the member 17.
[0045]
As shown in FIGS. 6 and 7, the pressurizing chamber 42 that presses the piston rod 11 is defined by the pressure receiving member 22 and the sub piston member 17, and the pressure applied to the object W through the piston rod 11. Is set by the product of the effective pressure receiving area of the pressure receiving member 22 and the fluid pressure P3. Further, the fluid pressure P3 supplied to the pressurizing chamber 42 is set to be smaller than the fluid pressure P4 supplied to the balance pressure chamber 34 in order to prevent reversal that may occur at the folded portion of the balance diaphragm 31. The Thus, when the piston rod output is set to be relatively small, the pressurizing diaphragm 33 can be removed and the breathing hole 51 formed in the piston rod 11 can be eliminated. Thereby, it can be set as a fluid pressure cylinder with a simple structure, and a low-cost fluid pressure cylinder can be provided.
[0046]
The fluid pressure cylinders 10a to 10d described so far move the piston rod 11 using the piston 15 when moving the piston rod 11 downward to a predetermined position, and apply pressure to the object W from the piston rod 11. When applying, the piston rod 11 is floated with respect to the piston 15, and the applied pressure is set by the fluid pressure P <b> 3 in the pressurizing chamber 42. For this reason, when the pressure is applied to the object W, the sliding resistance of the seal members 53 and 54 is not applied to the piston rod 11, and the deformation stroke of the diaphragm is set short by the downward movement of the piston rod 11 by the piston 15. Therefore, even when the piston rod 11 is reciprocated with a long stroke, it is possible to stably apply a high-precision pressurizing force with little error to the object W. Further, by forming the balance pressure chamber 34 that cancels the gravity applied to the piston rod 11, it is possible to set a highly accurate pressurizing force that is not affected by the gravity when the object W is pressurized.
[0047]
As described above, since an applied pressure can be applied to an object with high accuracy, it can be used, for example, to pressurize a squeegee head at a constant pressure in screen printing. In screen printing, a rubber squeegee is used to press the ink against paper or cloth using a mesh screen such as a silk screen, paint screen, or stencil screen. Inventive fluid pressure cylinders 10a-10d can be used. Other than that, if a certain pressure is applied to the object after moving the object for a predetermined stroke, such as a chip mounter for mounting a semiconductor chip on the mounting substrate or a tension roller of a winding machine The present invention can also be applied to.
[0048]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the illustrated embodiment, operation is performed using compressed air, but hydraulic oil may be used as the working fluid. Further, the balance pressure chamber 34 is not only partitioned by the diaphragms 31 and 32 for balancing and blocking, but is also closed by eliminating the breathing hole 52 provided in the end plate portion 16a of the main piston member 16. The diaphragm 32 may be removed, and the balance pressure chamber 34 may be defined only by the diaphragm 31 for balance.
[0049]
In addition, as indicated by a two-dot chain line in FIG. 6, a communication hole 65 for communicating the advance pressure chamber 55 and the pressurizing chamber 42 may be formed in the sub piston member 17. In this case, the supply / discharge port 45 and the fluid supply passage 43 formed in the pressure rod 39 are removed. When the fluid pressure cylinder 10c is operated, the piston 15 is moved downward by supplying the fluid pressure P1 from the supply / discharge port 56 to the forward pressure chamber 55, and the piston rod is moved by the fluid pressure P1 also supplied to the pressurizing chamber 42. 11 is pressed. At this time, the fluid pressure P1 is set smaller than the fluid pressure P4 in order to prevent the inversion that may occur in the folded portion 31c of the balance diaphragm 31. The communication hole 65 can also be formed in the fluid pressure cylinders 10a, 10b, and 10d.
[0050]
Further, in the fluid pressure cylinders 10a to 10d, pistons are connected so that the supply / discharge ports 40 and 45 formed in the pressure rod 39 and the fluid supply channels 41 and 43 communicate with the balance pressure chamber 34 and the pressurizing chamber 42, respectively. The rod 11 may be formed, whereby the pressure rod 39 can be removed, and the fluid pressure cylinders 10a to 10d having a simple configuration can be provided.
[0051]
Furthermore, it goes without saying that the piston rod 11 made of one member may be formed by integrally forming the pressure receiving member 22, the rod collar 23, and the rod member 24. Needless to say, a precision pressure reducing valve may be provided on the upstream side of the supply / discharge port 40 so that the fluid pressure P4 is always kept constant.
[0052]
The fluid pressure cylinders 10a to 10d may be used not only vertically attached to various devices but also attached to be inclined. That is, even if a part of gravity acting on the piston rod 11 affects the operation of the piston rod 11, the fluid pressure cylinders 10a to 10d of the present invention can be applied.
[0053]
【The invention's effect】
According to the present invention, by supplying fluid pressure to the balance pressure chamber defined by the balance diaphragm, it is possible to apply thrust against the gravity in the backward direction to the piston rod, which acts on the piston rod. Gravity can be offset. Moreover, the piston rod can be pushed in the forward direction by supplying fluid pressure to the pressurizing chamber defined by the piston and the piston rod. Because of these, after moving the piston rod using the piston, the piston rod can be pressed with high accuracy and no fluctuation without being affected by gravity acting on the piston rod or sliding resistance of the piston. Can do.
[0054]
In addition to the balance diaphragm, the balance pressure chamber is defined by using a closing diaphragm attached to the piston and piston rod, so that the volume change of the balance pressure chamber relative to the stroke of the piston rod can be suppressed. The pressure fluctuation in the balance pressure chamber can be suppressed. Thereby, the dead weight which acts on a piston rod with high precision can be canceled.
[0055]
By forming the pressurizing chamber using the pressurizing diaphragm, the fluid pressure supplied to the pressurizing chamber can be increased and the piston rod can be pressed with high output.
[0056]
A pressure rod that forms a fluid supply passage that communicates with the balance pressure chamber protrudes from the cylinder body and is provided in the sub-piston member. The fluid pressure can be reliably and easily supplied.
[0057]
By forming a fluid supply passage communicating with the pressurizing chamber in the pressure rod, fluid pressure can be reliably and easily supplied to the pressurizing chamber defined by the piston that reciprocates with respect to the cylinder body. it can.
[0058]
A fluid pressure cylinder having a simple configuration can be provided by forming a communicating hole in the auxiliary piston member for communicating the pressurizing chamber and the forward pressure chamber. Further, by forming a fluid supply passage communicating with the pressurizing chamber or the balance pressure chamber in the piston rod, a fluid pressure cylinder having a simple configuration can be provided.
[0059]
By providing the rotation stopper, the relative rotation of the piston rod with respect to the piston is prevented, so that the durability of the diaphragm can be improved. Thereby, the reliability of the fluid pressure cylinder and the accuracy of the applied pressure can be improved, and an excellent fluid pressure cylinder that is easy to use at low cost can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a fluid pressure cylinder according to an embodiment of the present invention, showing a state in which a piston moves backward.
2 is a longitudinal sectional view of the fluid pressure cylinder of FIG. 1 showing a state in which a piston has moved forward. FIG.
3 is a cross-sectional view taken along line AA in FIG.
4 is an enlarged cross-sectional view showing a part of the fluid pressure cylinder of FIG. 1. FIG.
FIG. 5 is a longitudinal sectional view of a fluid pressure cylinder according to another embodiment of the present invention.
FIG. 6 is a longitudinal sectional view showing a fluid pressure cylinder according to still another embodiment of the present invention.
FIG. 7 is a longitudinal sectional view showing a fluid pressure cylinder according to still another embodiment of the present invention.
[Explanation of symbols]
10a-10d Fluid pressure cylinder
11 Piston rod
12 Cylinder body
13 Cylinder tube
14a, 14b End cover
15 piston
16 Main piston member
16a End plate part
16b cylindrical part
16c Annular part
17 Sub piston member
17a End plate part
17b Annular part
18 Screw joint
20,21 sleeve
22 Pressure receiving member
23 Rod color
24 Rod member
25, 26 Through hole
27 head
28 Sliding bearing
31 Diaphragm for balance
32 Diaphragm for occlusion
33 Diaphragm for pressurization
31a-33a center
31b to 33b Flange
31c-33c Folding part
31d-33d cylindrical part
34 Balance pressure chamber
35-37 Fluid supply passage
38 communication hole
39 Pressure rod
40 Supply / Discharge port
41 Fluid supply passage
42 Pressurizing chamber
43 Fluid supply passage
44 communication hole
45 Supply / discharge port
46-48 annular groove
51,52 breathing hole
53, 54 Seal member
55 Lowering pressure chamber (forward pressure chamber)
56 Supply / discharge port
57 Spring chamber
58 Compression coil spring
59 Stopper surface
60 breathing hole
61 Anti-rotation key (anti-rotation)
62 Ascending pressure chamber (retracting pressure chamber)
63 Supply / discharge port
64 Seal member
65 communication hole
P1 to P4 Fluid pressure

Claims (11)

A piston which is incorporated in the cylinder body so as to be reciprocally movable in the axial direction between a forward limit position and a backward limit position, and which defines a forward pressure chamber in which forward fluid pressure is applied in the cylinder body ;
A piston rod projecting from said piston reciprocation freely supported axially one end portion of the cylinder body with a pressure chamber to partition formed within said piston,
A balancing diaphragm mounted between the piston and the piston rod;
A closing diaphragm that is mounted between the piston and the piston rod, defines a balance pressure chamber by the balancing diaphragm, and applies a fluid pressure in a backward direction to the piston rod ;
A fluid supply passage communicating with the balance pressure chamber;
A fluid pressure cylinder, wherein the piston rod is pressed in the forward direction by the fluid pressure in the pressurizing chamber in a state in which the fluid pressure in the balance pressure chamber is applied to the piston rod in the backward direction. 2. The fluid pressure cylinder according to claim 1 , further comprising a pressurizing diaphragm that is mounted between the piston and the piston rod and defines the pressurizing chamber. 3. The fluid pressure cylinder according to claim 1, wherein the fluid pressure cylinder is a single acting cylinder that applies an external force in a backward direction to the piston. 3. The fluid pressure cylinder according to claim 1, wherein the cylinder body is a double-acting cylinder in which a receding pressure chamber for applying fluid pressure in a receding direction to the piston is provided in the cylinder body. The fluid pressure cylinder according to any one of claims 1-4, to regulate the main piston member to which the piston rod passes, the movement stroke for the main piston member of the piston rod attached to said main piston member A fluid pressure cylinder, wherein the piston is formed by a sub piston member. The fluid pressure cylinder according to claim 5, and characterized by mounting a pressure rod, wherein the fluid supply passage communicating with the balance pressure chamber is formed on the auxiliary piston member is protruded from the other end of the cylinder body Fluid pressure cylinder. 7. The fluid pressure cylinder according to claim 6 , wherein a fluid supply passage communicating with the pressurizing chamber is formed in the pressure rod. The fluid pressure cylinder according to claim 5 or 6 , wherein a communication hole for communicating the pressurizing chamber and the forward pressure chamber is formed in the sub piston member. The fluid pressure cylinder according to any one of claims 1 to 4 , wherein a fluid supply passage communicating with the balance pressure chamber is formed in the piston rod. The fluid pressure cylinder according to any one of claims 1 to 4 , wherein a fluid supply passage communicating with the pressurizing chamber is formed in the piston rod. The fluid pressure cylinder according to any one of claims 1 to 10 , wherein a rotation stopper is provided between the piston and the piston rod.

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