Fluid pressure cylinder

Abstract

A fluid pressure cylinder has a first cylinder body (20) and a second cylinder body (36) arranged side by side. The first cylinder body has a first accumulator chamber (32) on the top side and a second accumulator chamber (34) on the rod side, which are divided by a first piston (24). The second cylinder body has an open chamber (48) on the top side and a drive chamber (50) on the rod side, which are divided by a second piston (40). The end of a first piston rod (26) connected to the first piston and the end of a second piston rod (42) connected to the second piston are connected to each other. The fluid pressure cylinder has a single supply and discharge port (16) for supplying and discharging pressurized fluid to the second accumulator chamber and the drive chamber. A switching valve (58) for switching the communication state between the first accumulator chamber and the second accumulator chamber is provided on the first piston.

Description

Background Technology

[0001] The present invention relates to a fluid pressure cylinder having a movable cylinder section and an output cylinder section. Technical Field

[0002] Previously, it was known that fluid pressure cylinders used for clamping mechanisms, etc., were provided with a separate moving cylinder for moving the end of the piston rod to a position close to the workpiece and an output cylinder for performing the required work on the workpiece at the end of the piston rod.

[0003] For example, Japanese Patent No. 5048696 describes a cylinder in which a booster cylinder is disposed between a pair of drive cylinders. In this cylinder, during the period when air is supplied to the second cylinder chamber of the drive cylinder and the booster rod and drive rod advance, there is no pressure difference between the third and fourth cylinder chambers of the booster cylinder, and no forward thrust is applied to the booster rod. On the other hand, when the connecting plate connecting the booster rod and drive rod abuts against the workpiece and the booster rod and drive rod stop, the pressure in the first cylinder chamber of the drive cylinder decreases, and the valve core of the first valve device switches to the booster position. With the fourth cylinder chamber pressurized, the third cylinder chamber becomes atmospheric pressure, thus applying a forward thrust to the booster rod.

[0004] However, in the aforementioned cylinder, air needs to be supplied to the first chamber of the drive cylinder when the drive rod is retracted, which limits the reduction of air consumption. Furthermore, it is essential to have two pipes between the switching valve and the drive cylinder, which switches the air supply and exhaust to the first and second chambers. Moreover, in the case of a series-type fluid pressure cylinder where the piston rods of the moving cylinder and the output cylinder are coaxially connected, in addition to the same problems as above, there is also the issue of the fluid pressure cylinder becoming excessively long and large. Summary of the Invention

[0005] The present invention was made in view of the following problems, and its object is to provide a fluid pressure cylinder having a movable cylinder section and an output cylinder section, which avoids large size and can minimize the consumption of pressurized fluid. Furthermore, its object is to provide a fluid pressure cylinder that requires only a single connecting pipe.

[0006] The fluid pressure cylinder of this invention has a first cylinder body and a second cylinder body arranged side by side. The first cylinder body has a first accumulator chamber on the top side and a second accumulator chamber on the rod side, defined by a first piston. The second cylinder body has an open chamber on the top side and a drive chamber on the rod side, defined by a second piston. Furthermore, the ends of the first piston rod connected to the first piston and the second piston rod connected to the second piston are connected to each other. The fluid pressure cylinder has a single supply and discharge port for supplying and discharging pressurized fluid to the second accumulator chamber and the drive chamber. A switching valve for switching the connection state between the first and second accumulator chambers is provided on the first piston.

[0007] According to the aforementioned fluid pressure cylinder, since the supply of pressurized fluid to the second cylinder section, which serves as a moving cylinder, only needs to be performed when the second piston moves in one direction (reverse direction), the consumption of pressurized fluid can be reduced to the greatest extent. Furthermore, since the first and second cylinder sections are arranged side-by-side, the large size of the fluid pressure cylinder can be prevented. Moreover, since only one pipe connected to the supply and discharge ports is needed for the piping connected to the fluid pressure cylinder, piping management is simplified.

[0008] Furthermore, the fluid pressure cylinder according to the present invention has a first cylinder body and a second cylinder body arranged side by side. The first cylinder body has a first accumulator chamber on the top side and a second accumulator chamber on the rod side, divided by a first piston. The second cylinder body has an open chamber on the top side and a drive chamber on the rod side, divided by a second piston. The ends of the first piston rod connected to the first piston and the second piston rod connected to the second piston are connected to each other. A switching valve for switching the connection state between the first and second accumulator chambers is provided on the first piston. During the pull-in process, with the first and second accumulator chambers connected, pressurized fluid from a fluid supply source is supplied to the drive chamber and the second accumulator chamber. During the push-out process, with the first and second accumulator chambers connected, pressurized fluid in the drive chamber is discharged.

[0009] According to the above-described fluid pressure cylinder, since the supply of pressurized fluid to the second cylinder section, which is a moving cylinder, only occurs when the second piston moves in one direction (reverse direction), i.e., only during the pull-in process, the consumption of pressurized fluid can be reduced to the greatest extent. Furthermore, since the first and second cylinder sections are arranged side-by-side, the large size of the fluid pressure cylinder can be prevented.

[0010] The fluid pressure cylinder of this invention allows the first piston to move forward by connecting the first and second accumulator chambers to each other and utilizing the pressure-bearing area difference of the first piston in the first cylinder section, which is configured as an output cylinder. That is, since the first cylinder section can function as a moving cylinder for forward movement, pressurized fluid only needs to be supplied to the second cylinder section when the second piston moves in the reverse direction, minimizing pressurized fluid consumption. Furthermore, since it has a single supply / discharge port for supplying and discharging pressurized fluid to the second accumulator chamber and the drive chamber, only one piping connection to the fluid pressure cylinder is required, simplifying piping management.

[0011] The above-described objectives, features, and advantages will be readily understood by referring to the accompanying drawings and illustrating the preferred embodiments below. Attached Figure Description

[0012] Figure 1 This is a perspective view of the fluid pressure cylinder according to an embodiment of the present invention.

[0013] Figure 2 yes Figure 1 Front view of the fluid pressure cylinder.

[0014] Figure 3 yes Figure 1 A top view of the fluid pressure cylinder.

[0015] Figure 4 It is along Figure 2 Section of IV-IV line Figure 1 A cross-sectional view of the fluid pressure cylinder.

[0016] Figure 5 It is along Figure 3 VV line section Figure 1 A cross-sectional view of the fluid pressure cylinder.

[0017] Figure 6 It is the end of the ejection process and Figure 4 The corresponding diagram.

[0018] Figure 7 yes Figure 4 Enlarged view of part A.

[0019] Figure 8 yes Figure 6 Enlarged view of part B.

[0020] Figure 9 The terminal of the pull-in process is schematically represented by a circuit diagram that includes the supply and discharge switching valve. Figure 1 A diagram of a fluid pressure cylinder.

[0021] Figure 10The ejection process is schematically represented by a circuit diagram that includes the supply and discharge switching valve. Figure 1 A diagram of a fluid pressure cylinder.

[0022] Figure 11 The terminal of the ejection process is schematically represented by a circuit diagram that includes the supply and discharge switching valve. Figure 1 A diagram of a fluid pressure cylinder.

[0023] Figure 12 The pull-in process is schematically represented using a circuit diagram that includes the supply and discharge switching valve. Figure 1 A diagram of a fluid pressure cylinder. Detailed Implementation

[0024] Preferred embodiments will be described with reference to the accompanying drawings. The fluid pressure cylinder 10 is connected to a supply / discharge switching valve 90 and used for tasks such as workpiece positioning. Furthermore, the fluid used is a pressurized fluid such as compressed air.

[0025] like Figure 1 , Figure 4 and Figure 6 As shown, the fluid pressure cylinder 10 has a cuboid cylinder body 12, which has a first cylinder bore 22 and a second cylinder bore 38 with a smaller diameter than the first cylinder bore 22. The first cylinder bore 22 and the second cylinder bore 38 extend from one end of the cylinder body 12 along its length and are arranged side by side.

[0026] One end of the first cylinder bore 22 is closed by a first top end cap 28, and the other end of the first cylinder bore 22 is closed by a first rod end cap 30. A first piston 24 is slidably mounted on the first cylinder bore 22, forming the first cylinder body 20. The first cylinder bore 22 is divided by the first piston 24 into a first accumulator chamber 32 on the side of the first top end cap 28 (top side) and a second accumulator chamber 34 on the side of the first rod end cap 30 (rod side). As will be clarified in the following description of its function, the first cylinder body 20 serves not only as an output cylinder but also as a forward-moving cylinder.

[0027] One end of the second cylinder bore 38 is closed by the second top end cap 44, and the other end of the second cylinder bore 38 is closed by the second rod end cap 46. A second piston 40 is slidably mounted on the second cylinder bore 38, forming the second cylinder body portion 36. The second cylinder bore 38 is divided by the second piston 40 into an open chamber 48 on the side of the second top end cap 44 (top side) and a drive chamber 50 on the side of the second rod end cap 46 (rod side). The second cylinder body portion 36 serves as a moving cylinder for reversing. The first cylinder body portion 20 and the second cylinder body portion 36 are arranged side by side.

[0028] One end of the first piston rod 26 is connected to the first piston 24, and the other end of the first piston rod 26 extends outward through the first rod side end cap 30. One end of the second piston rod 42 is connected to the second piston 40, and the other end of the second piston rod 42 extends outward through the second rod side end cap 46.

[0029] The other end of the first piston rod 26 and the other end of the second piston rod 42 are connected by a rectangular plate-shaped connecting plate 52. Specifically, the other end of the first piston rod 26 is inserted into a first through hole 52a formed in the connecting plate 52. The cylindrical output components 54 and the first nut 56a on both sides of the first through hole 52a are screwed into the first piston rod 26, thereby fixing the first piston rod 26 to the connecting plate 52. In addition, the other end of the second piston rod 42 is inserted into a second through hole 52b formed in the connecting plate 52. The second nut 56b and the third nut 56c on both sides of the second through hole 52b are screwed into the second piston rod 42, thereby fixing the second piston rod 42 to the connecting plate 52.

[0030] In this configuration, the inner diameter of the first through-hole 52a is larger than the outer diameter of the first piston rod 26, and the inner diameter of the second through-hole 52b is larger than the outer diameter of the second piston rod 42. This allows for the absorption of manufacturing and assembly errors while maintaining the parallelism of the first piston rod 26 and the second piston rod 42, and reduces the sliding resistance of the first piston 24 and the second piston 40. The first piston 24 and the second piston 40 move integrally via the first piston rod 26, the connecting plate 52, and the second piston rod 42.

[0031] Hereinafter, the process of moving the first piston 24 and the second piston 40 in the direction in which the first piston rod 26 and the second piston rod 42 are pushed out from the cylinder body 12 (forward direction) is called the "pull-out process". The process of moving the first piston 24 and the second piston 40 in the direction in which the first piston rod 26 and the second piston rod 42 are pulled into the cylinder body 12 (reverse direction) is called the "pull-in process". The fluid pressure cylinder 10 operates when the output component 54 is pushed out integrally with the first piston rod 26.

[0032] like Figure 1 and Figure 3 As shown, a supply / exhaust port 16 and an open port 18 are provided on the upper surface of the cylinder body 12. The supply / exhaust port 16 is connected to the supply / exhaust switching valve 90 via a pipe 94 (see reference). Figure 9 Port 18 is open to the atmosphere.

[0033] Inside the cylinder body 12 are provided a first flow path 14a connecting the second accumulator chamber 34 to the supply and exhaust port 16, a second flow path 14b connecting the drive chamber 50 to the supply and exhaust port 16, and a third flow path 14c connecting the open chamber 48 to the open port 18 (see reference). Figure 9A one-way valve 14e is arranged in the first flow path 14a, which allows fluid to flow from the supply / discharge switching valve 90 toward the second accumulator 34 and prevents fluid from flowing from the second accumulator 34 toward the supply / discharge switching valve 90. Furthermore, a fourth flow path 14d is provided inside the cylinder body 12, which connects the radial passage 80 of the discharge switching valve 74 (described later) to the supply / discharge port 16. Figure 5 A portion of the first flow path 14a and a portion of the fourth flow path 14d are shown.

[0034] The first piston 24 is provided with a switching valve 58 for switching the connection state between the first accumulator 32 and the second accumulator 34. The switching valve 58 has a first push rod 60 protruding into the second accumulator 34.

[0035] like Figure 7 As shown, the first push rod 60 is slidably supported within the guide hole 62, which is formed through the first piston 24 in the axial direction. A conductive passage 64 is provided inside the first push rod 60 to connect the first accumulator chamber 32 and the second accumulator chamber 34. This conductive passage 64 consists of a first hole 64a extending upwards in diameter through the first push rod 60 and a second hole 64b branching from the middle of the first hole 64a and extending towards the first accumulator chamber 32. The two ends of the first hole 64a open into an annular gap 66 between the outer periphery of the first push rod 60 and the wall of the guide hole 62, and the end of the second hole 64b communicates with the first accumulator chamber 32. When the first push rod 60 protrudes beyond a certain distance into the second accumulator chamber 34, the annular gap 66 communicates with the second accumulator chamber 34.

[0036] The first push rod 60 is forced in a direction protruding into the second accumulator chamber 34 by a helical spring 68 disposed between the spring bracket 72, which is fixed to the first piston 24, and the first push rod 60. The protrusion of the first push rod 60 is limited by the engagement of the stepped portion 60a of the first push rod 60 with the stepped portion 62a of the guide hole 62, thus preventing the first push rod 60 from dislodging. Furthermore, a hole 72a is provided in the center of the spring bracket 72.

[0037] Near the end of the ejection process, the first push rod 60 abuts against the first rod-side end cap 30, is pressed in against the force of the coil spring 68, and slides within the guide hole 62. When the first push rod 60 is pressed in, the gasket 70 fitted around the outer periphery of the first push rod 60 abuts against the wall of the guide hole 62, thereby cutting off the communication between the annular gap 66 and the second accumulator chamber 34. That is, near the end of the ejection process, the switching valve 58 cuts off the communication between the first accumulator chamber 32 and the second accumulator chamber 34. The first push rod 60 can be pressed in to a position where it does not protrude from the end face of the first piston 24.

[0038] A discharge switching valve 74 is provided on the first rod side end cap 30. This discharge switching valve 74 can switch the connection state between the second accumulator 34 and the supply / discharge switching valve 90 to discharge the pressurized fluid in the second accumulator 34. The discharge switching valve 74 has a second push rod 76 protruding into the second accumulator 34. Viewed from the axial direction of the first piston rod 26, the first push rod 60 of the switching valve 58 and the second push rod 76 of the discharge switching valve 74 are positioned at equal distances from each other in opposite directions (a difference of 180 degrees) from this axis.

[0039] like Figure 8 As shown, the second push rod 76 is slidably supported within the guide hole 78, which is formed through the first rod-side end cap 30 in the axial direction. The guide hole 78 of the first rod-side end cap 30 has a small-diameter hole portion 78a on the side close to the second accumulator chamber 34 and a large-diameter hole portion 78b on the side away from the second accumulator chamber 34. The second push rod 76 has a small-diameter shaft portion 76a inserted into the small-diameter hole portion 78a and a large-diameter shaft portion 76b inserted into the large-diameter hole portion 78b. O-rings 82a and 82b are fitted on the outer periphery of the small-diameter shaft portion 76a and the large-diameter shaft portion 76b.

[0040] The second push rod 76 is subjected to force in a direction protruding into the second accumulator 34 toward the small-diameter shaft portion 76a via a helical spring 84 disposed between the spring bracket 86, which is fixed to the first rod end cap 30, and the second push rod 76. The protrusion of the second push rod 76 is limited by engaging the stepped portion 76c disposed between the small-diameter shaft portion 76a and the large-diameter shaft portion 76b and the stepped portion 78c disposed between the small-diameter shaft portion 78a and the large-diameter shaft portion 78b.

[0041] A radial passage 80 is provided on the first rod-side end cap 30, with one end open on the outer peripheral surface of the first rod-side end cap 30 and the other end open on the large-diameter bore 78b. As described above, the radial passage 80 communicates with the fourth flow path 14d of the cylinder body 12. A discharge passage 88 is provided inside the second push rod 76 to communicate with the second accumulator 34 and the radial passage 80. The discharge passage 88 is composed of a first bore 88a and a second bore 88b. The first bore 88a passes through the small-diameter shaft portion 76a of the second push rod 76 in the diametrical direction, and the second bore 88b passes through the first bore 88a and passes through the second push rod 76 in the axial direction.

[0042] Near the end of the ejection process, the second push rod 76 abuts against the first piston 24, overcoming the force of the coil spring 84 and being pressed in, thereby sliding within the guide hole 78. When the second push rod 76 is pressed in, the O-ring 82a fitted to the small-diameter shaft portion 76a leaves the wall of the small-diameter hole portion 78a, and the second accumulator 34 communicates with the radial passage 80 of the first rod-side end cap 30 via the discharge passage 88 of the second push rod 76. Therefore, the second accumulator 34 is connected to the supply and discharge switching valve 90 via the discharge passage 88, the radial passage 80, the fourth flow path 14d, and the supply and discharge port 16. That is, near the end of the ejection process, the discharge switching valve 74 connects the second accumulator 34 and the supply and discharge switching valve 90. The second push rod 76 can be pressed in to a position where it does not protrude from the end face of the first rod-side end cap 30.

[0043] like Figure 9 As shown, the supply / discharge switching valve 90 has a first port 92a to a third port 92c, and is configured as a two-position, three-port switching valve capable of switching between a first position and a second position. The first port 92a is connected to the supply / discharge port 16 of the cylinder body 12 via a pipe 94. Additionally, the second port 92b is connected to a fluid supply source (compressor) 96, and the third port 92c is connected to an outlet 99 equipped with a muffler 98. When the supply / discharge switching valve 90 is in the first position, the first port 92a and the second port 92b are connected; when the supply / discharge switching valve 90 is in the second position, the first port 92a and the third port 92c are connected. Only one pipe 94 is required to connect the fluid pressure cylinder 10 and the supply / discharge switching valve 90.

[0044] The fluid pressure cylinder 10 involved in this embodiment is configured as described above, and its operation will be explained below. Furthermore, in Figures 9-12 In the middle, the double-dotted line represents the outline of cylinder 12.

[0045] like Figure 4 As shown, the initial state is defined as follows: the first piston 24 is positioned between the first top end cap 28 and the first rod end cap 30, and the pressures of the first accumulator chamber 32, the second accumulator chamber 34, the drive chamber 50, and the open chamber 48 are all equal to atmospheric pressure.

[0046] In this initial state, the supply / discharge switching valve 90 is in the second position, and the supply / discharge port 16 is connected to the discharge port 99. Additionally, the first push rod 60 of the opening switching valve 58 and the second push rod 76 of the discharge switching valve 74 protrude into the second accumulator chamber 34. Therefore, the first accumulator chamber 32 and the second accumulator chamber 34 are in communication with each other, and the connection between the second accumulator chamber 34 and the supply / discharge switching valve 90 via the fourth flow path 14d is severed.

[0047] When the supply / discharge switching valve 90 switches from the initial state to the first position, the supply / discharge port 16 is connected to the fluid supply source 96. Pressurized fluid from the fluid supply source 96 is supplied from the supply / discharge port 16 to the drive chamber 50 via the second flow path 14b, and from the supply / discharge port 16 to the second accumulator chamber 34 via the first flow path 14a, which is equipped with a check valve 14e. When pressurized fluid is supplied to the drive chamber 50, the second piston 40 is driven toward the second top end cap 44. The first piston 24 also moves integrally with the second piston 40 and is driven toward the first top end cap 28.

[0048] On the other hand, the pressurized fluid supplied to the second accumulator 34 is not only stored in the second accumulator 34, but also in the first accumulator 32, which is in communication with the second accumulator 34. Furthermore, the first piston rod 26 and the second piston rod 42 are pulled to their maximum extent, and high-pressure fluid at the same pressure is stored in both the first accumulator 32 and the second accumulator 34 (see reference). Figure 9 At this time, although the second piston 40 abuts against the second top end cap 44, the first piston 24 does not abut against the first top end cap 28.

[0049] Next, when the supply / discharge switching valve 90 is switched to the second position, the supply / discharge port 16 is connected to the discharge port 99. The pressurized fluid in the drive chamber 50 passes through the second flow path 14b and the supply / discharge port 16, and after passing through the supply / discharge switching valve 90, is discharged to the outside from the discharge port 99. The pressure in the drive chamber 50 is reduced to the same atmospheric pressure as the pressure in the open chamber 48, and the driving force acting on the second piston 40 becomes zero.

[0050] On the other hand, the pressurized fluid in the second accumulator 34 is not discharged through the action of the one-way valve 14e. Although the pressure of the fluid accumulated in the first accumulator 32 and the pressure of the fluid accumulated in the second accumulator 34 at the same pressure act on the first piston 24, they act on the first piston 24 with an area difference equivalent to the cross-section of the first piston rod 26. Therefore, the force by which the first piston 24 is pressed against the first rod-side end cap 30 by the fluid pressure in the first accumulator 32 exceeds the force by which the first piston 24 is pressed against the first top-side end cap 28 by the fluid pressure in the second accumulator 34. The first piston 24 is driven towards the first rod-side end cap 30, thereby initiating the ejection process (see reference). Figure 10 ).

[0051] As described above, the ejection process is carried out without supplying any pressurized fluid from the fluid supply source 96 to the fluid pressure cylinder 10. Near the end of the ejection process, the first push rod 60 of the switching valve 58 abuts against the first rod-side end cap 30, and the second push rod 76 of the discharge switching valve 74 abuts against the first piston 24. This disconnects the communication between the first accumulator 32 and the second accumulator 34, and the second accumulator 34 is connected to the supply / discharge switching valve 90 via the fourth flow path 14d (see reference). Figure 11 ).

[0052] The pressurized fluid accumulated in the second accumulator 34 passes through the fourth flow path 14d and the supply / discharge port 16, and after passing through the supply / discharge switching valve 90 located in the second position, is discharged to the outside from the discharge port 99. The pressurized fluid accumulated in the first accumulator 32 is prevented from flowing into the second accumulator 34 and remains in the first accumulator 32. Therefore, the fluid pressure in the first accumulator 32 significantly exceeds the fluid pressure in the second accumulator 34, and the first piston 24 is pressed against the first rod-side end cap 30 with a greater thrust. That is, at the end of the ejection process, the fluid pressure cylinder 10 exerts its maximum force.

[0053] The pressurized fluid discharged from the second accumulator 34 is the pressurized fluid present in the second accumulator 34, which has a reduced volume near the end of the ejection process, and the amount of this pressurized fluid is relatively small. The amount of pressurized fluid supplied to the second accumulator 34 during the subsequent pull-in process can be equivalent to this discharged amount.

[0054] Near the end of the aforementioned ejection process, the first push rod 60, which abuts against the first rod-side end cap 30 and receives its reaction force, applies a force to the first piston 24 via the coil spring 68. Additionally, the second push rod 76, supported on the first rod-side end cap 30 via the coil spring 84, also abuts against the first piston 24 and applies a force in the same direction. Since these forces act at equal distances away from the axis of the first piston rod 26 in opposite directions, by adjusting the spring constants of the coil springs 68 and 84, as long as these forces are of equal magnitude, no torque will be generated that would cause the first piston 24 to tilt.

[0055] Next, when the supply / discharge switching valve 90 is switched to the first position, pressurized fluid from the fluid supply source 96, after passing through the supply / discharge switching valve 90, is supplied to the drive chamber 50 through the supply / discharge port 16 and the second flow path 14b, and is also supplied to the second accumulator chamber 34 through the supply / discharge port 16 and the first flow path 14a, on which the one-way valve 14e is arranged. As a result, the second piston 40 is driven toward the second top end cap 44, and the first piston 24 is also driven toward the first top end cap 28, thereby pulling in the process start (see reference). Figure 12 ).

[0056] When the pull-in process begins, the first push rod 60 of the switching valve 58, protruding from the first piston 24 under the force of the coil spring 68, leaves the first rod side end cap 30. Simultaneously, the second push rod 76 of the discharge switching valve 74, protruding from the first rod side end cap 30 under the force of the coil spring 84, leaves the first piston 24. The protrusion of the first push rod 60 connects the first accumulator chamber 32 and the second accumulator chamber 34. The protrusion of the second push rod 76, although cutting off the connection between the second accumulator chamber 34 and the supply / discharge switching valve 90 via the fourth flow path 14d, allows the pressurized fluid to continue flowing from the supply / discharge switching valve 90 to the second accumulator chamber 34 through the first flow path 14a.

[0057] Therefore, the pressurized fluid from the fluid supply source 96, in addition to being supplied to the drive chamber 50, is also supplied / accumulated in the second accumulator chamber 34 via the first flow path 14a, and is also supplied / accumulated in the first accumulator chamber 32 via the switching valve 58. This pull-in process, through the contact between the second piston 40 and the second top end cap 44, pulls the first piston rod 26 and the second piston rod 42 to their maximum extent, thereby accumulating high-pressure fluid at the same pressure in the first accumulator chamber 32 and the second accumulator chamber 34 (see reference). Figure 9 ).

[0058] Subsequently, the push-out process of switching the supply / discharge switching valve 90 to the second position and the pull-in process of switching the supply / discharge switching valve 90 to the first position are repeatedly executed. Furthermore, in order to enable the pull-in action when pressurized fluid from the fluid supply source 96 is supplied to the drive chamber 50 and the second accumulator 34, which is in a connected state with the first accumulator 32, the difference between the cross-sectional area of ​​the second piston 40 and the cross-sectional area of ​​the second piston rod 42 is larger than the cross-sectional area of ​​the first piston rod 26.

[0059] According to the fluid pressure cylinder 10 of this embodiment, the first piston 24 can be moved in the forward direction by utilizing the pressure-bearing area difference of the first piston 24 in the first cylinder body 20. That is, since the first cylinder body 20 can function as a moving cylinder for forward movement, the supply of pressurized fluid to the second cylinder body 36 only needs to be performed when the second piston 40 moves in the backward direction, thereby minimizing the consumption of pressurized fluid.

[0060] In addition, since the supply and discharge of pressurized fluid from the fluid supply source 96 to the second accumulator chamber 34 and the drive chamber 50 can be carried out through a single supply and discharge port 16, only one pipe 94 is needed to connect the piping to the fluid pressure cylinder 10, making piping management easier.

[0061] Furthermore, at the end of the ejection process, the connection between the first accumulator 32 and the second accumulator 34 is cut off, and the pressure fluid accumulated in the second accumulator 34 is discharged, so that the maximum force can be exerted when working on the workpiece.

[0062] Furthermore, since the first cylinder section 20, which functions as both an output cylinder and a forward-moving cylinder, and the second cylinder section 36, which functions as a backward-moving cylinder, are arranged side by side, the overall length of the fluid pressure cylinder 10 can be significantly shortened compared to the case where the moving cylinder and the output cylinder are arranged in series.

[0063] In addition, since the supply and discharge switching valve 90 connected to the supply and discharge port 16 can be configured as a two-position three-port switching valve, the structure of the supply and discharge switching valve 90 can be simplified.

[0064] In this embodiment, although the positional relationship between the first push rod 60 and the second push rod 76 is such that they are equidistant from each other when viewed from the axial direction of the first piston rod 26, their positional relationship is not limited to this, and they can be arranged in appropriate positions within a range where they do not contact each other.

[0065] The fluid pressure cylinder involved in this invention is not limited to the above-described embodiments. It goes without saying that various structures can be adopted without departing from the spirit of this invention.

Claims

1. A fluid pressure cylinder having a first cylinder body portion (20) and a second cylinder body portion (36) arranged side by side, characterized in that, The first cylinder has a first accumulator chamber (32) on the top side and a second accumulator chamber (34) on the rod side, divided by a first piston (24). The second cylinder has an open chamber (48) on the top side and a drive chamber (50) on the rod side, divided by a second piston (40). The end of the first piston rod (26) connected to the first piston and the end of the second piston rod (42) connected to the second piston are connected to each other. The fluid pressure cylinder has a single supply and discharge port (16) for supplying and discharging pressurized fluid to the second accumulator chamber and the drive chamber. A switching valve (58) for switching the connection state between the first accumulator chamber and the second accumulator chamber is provided on the first piston. The fluid pressure cylinder is provided with an open port (18) that allows the open chamber to be opened to the atmosphere.

2. The fluid pressure cylinder as described in claim 1, characterized in that, The second accumulator is connected to the supply and discharge port via a flow path (14a) provided with a one-way valve (14e), which allows fluid to flow from the supply and discharge port toward the second accumulator and prevents fluid from flowing from the second accumulator toward the supply and discharge port.

3. The fluid pressure cylinder as described in claim 1, characterized in that, The first rod end cap (30) through which the first piston rod is inserted is provided with a discharge switching valve (74) for discharging pressurized fluid from the second accumulator chamber.

4. The fluid pressure cylinder as described in claim 3, characterized in that, The conduction switching valve has a first push rod (60) that can abut against the first rod side end cap. When the first push rod abuts against the first rod side end cap and is pressed in, the communication between the first accumulator chamber and the second accumulator chamber is cut off. The discharge switching valve has a second push rod (76) that can abut against the first piston. When the second push rod abuts against the first piston and is pressed in, the second accumulator chamber is connected to the supply and discharge port.

5. The fluid pressure cylinder as described in claim 4, characterized in that, Viewed from the axial direction of the first piston rod, the first push rod and the second push rod are positioned at equal distances away from the axis in opposite directions.

6. The fluid pressure cylinder as described in claim 1, characterized in that, The first piston rod and the second piston rod are connected by a connecting plate (52), which has a first through hole (52a) for the end of the first piston rod to be inserted and a second through hole (52b) for the end of the second piston rod to be inserted. The inner diameter of the first through hole is larger than the outer diameter of the first piston rod, and the inner diameter of the second through hole is larger than the outer diameter of the second piston rod.

7. The fluid pressure cylinder as described in claim 1, characterized in that, The supply and discharge ports are connected to a supply and discharge switching valve (90) via a piping (94), which is configured as a two-position three-port switching valve that switches between a first position connecting the supply and discharge ports to a fluid supply source (96) and a second position connecting the supply and discharge ports to a discharge outlet (99).

8. A fluid pressure cylinder having a first cylinder body portion and a second cylinder body portion arranged side by side, characterized in that, The first cylinder portion has a first accumulator chamber on the top side and a second accumulator chamber on the rod side, divided by a first piston. The second cylinder portion has an open chamber on the top side and a drive chamber on the rod side, divided by a second piston. The ends of the first piston rod connected to the first piston and the second piston rod connected to the second piston are connected to each other. A switching valve for switching the connection state between the first accumulator chamber and the second accumulator chamber is provided on the first piston. The fluid pressure cylinder is provided with an open port, which allows the open chamber to be open to the atmosphere. In the pull-in process, with the first and second accumulators connected to each other, pressurized fluid from a fluid supply source is supplied to the drive chamber and the second accumulator. In the push-out process, with the first and second accumulators connected to each other, pressurized fluid in the drive chamber is discharged.

9. The fluid pressure cylinder as described in claim 8, characterized in that, At the end of the ejection process, the communication between the first accumulator and the second accumulator is cut off, and the pressurized fluid in the second accumulator is discharged.

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