Cylinder device

Abstract

To provide a cylinder device including a mechanism for detecting a position of an output stage on three stages by utilizing an outer periphery of a piston rod of the output member and an inner wall of a housing.SOLUTION: An A passage Ap in which a compressed gas is supplied and a B passage Bp in which atmospheric air is exhausted are provided in a housing 2. A projection 12a pushing down a seal member 11 and an annular valve member 10 in an accompanied manner is provided in a piston rod 3. On a hollow inner wall in the housing, there are provided a sliding surface region 13 having such an inner diameter that the seal member 11a is abutted and a seal function effectively works, a free insertion region 14 having such a large inner diameter that the seal function of the seal member 11a does not work at all, and a valve member region 18 which has a large inner diameter that the annular valve member 10 is vertically movable, in which the annular valve member 10 is stored while enclosing the upper side with a ring face 2d and which communicates to the B passage Bp.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cylinder device, and more particularly to a cylinder that is applied to a cylinder device for fixing an object to be clamped. [Background technology]

[0002] The cylinder device transitions from an unclamped state to a clamped state due to the up and down movement of the output member. Patent Document 1 discloses a mechanism for detecting the position of the piston part in each state. Patent Document 1 discloses a cylinder having an output member that is moved up and down inside a housing by a pressure fluid. A first valve chamber is provided between the lower wall of the housing and the output member. A second valve chamber is hollowed out in the piston part and opens to the first valve chamber side. A valve rod protrudes from the lower wall of the housing and is inserted into the second valve chamber. A system of compressed gas for position detection is arranged using the first valve chamber, valve rod, and second valve chamber, separately from the path of the pressure fluid that drives the output member. The position of the output member is detected depending on whether the pressure of the system when compressed gas is sent to this system is high, low, or intermediate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-215074 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the mechanism for detecting the position of the output member in Patent Document 1, the second valve chamber is hollowed out in the output member, and the valve rod protruding from the bottom wall of the housing is inserted into the second valve chamber. For this reason, this configuration is difficult to apply to small cylinder devices. An object of the present invention is to provide a cylinder device provided with a mechanism for detecting the position of an output member in three stages by utilizing the outer periphery of the piston rod of the output member and the inner wall of the housing. [Means for solving the problem]

[0005] In the present invention, a cylinder device having a piston that moves up and down inside a housing by pressure fluid, A piston rod fixed to the piston; a seal member attached to a seal groove on an outer peripheral wall of the piston rod; a hollow inner wall within the housing along which the piston rod moves up and down; the housing is provided with a supply passage that supplies compressed gas to the inside of the hollow inner wall, a discharge passage that discharges the compressed gas supplied to the inside of the hollow inner wall to the atmosphere, and a pressure loss passage that allows the compressed gas supplied to the inside of the hollow inner wall to pass with a larger pressure loss than through the supply passage and the discharge passage and is in communication with the discharge passage, The hollow inner wall of the housing has a sliding surface area having an inner diameter such that the sealing function can be effectively performed when the seal member abuts against the sliding surface area, and a loose insertion area having an inner diameter large enough that the sealing function of the seal member does not work at all, and one loose insertion area is sandwiched between two sliding surface areas from above and below, and further, the two sliding surface areas are sandwiched between two loose insertion areas above and below the sliding surface areas, The supply passage, the discharge passage, and the pressure loss passage are each connected to one of the separate loose insertion areas, and the loose insertion area to which the supply passage is connected is adjacent to the loose insertion area to which the supply passage is connected in the vertical direction.

[0006] In addition, the present invention provides a cylinder device having a piston that moves up and down within a housing by pressure fluid, A piston rod fixed to the piston; a seal member attached to each of the seal grooves spaced apart above and below the outer peripheral wall of the piston rod; a hollow inner wall within the housing along which the piston rod moves up and down; the housing is provided with a supply passage that supplies compressed gas to the inside of the hollow inner wall, a discharge passage that discharges the compressed gas supplied to the inside of the hollow inner wall to the atmosphere, and a pressure loss passage that allows the compressed gas supplied to the inside of the hollow inner wall to pass with a larger pressure loss than through the supply passage and the discharge passage and is in communication with the discharge passage, The hollow inner wall of the housing has a sliding surface area having an inner diameter such that the sealing function can be effectively performed when the seal member abuts against the sliding surface area, and a loose insertion area having an inner diameter large enough that the sealing function of the seal member does not work at all, and one loose insertion area is sandwiched between two sliding surface areas from above and below, and further, the two sliding surface areas are sandwiched between two loose insertion areas above and below the sliding surface areas, Each of the supply passage, the discharge passage, and the pressure loss passage is connected to one of the separate loose insertion areas, and the loose insertion area to which the supply passage is connected is vertically adjacent to the loose insertion area to which the supply passage is connected, The upper and lower seal members are attached so as to be simultaneously positioned at the upper and lower sliding surface areas, respectively, during the process in which the piston rod moves up and down.

[0007] In addition, the present invention provides a cylinder device having a piston that moves up and down within a housing by pressure fluid, A piston rod fixed to the piston; a seal member attached to each of the seal grooves spaced apart above and below the outer peripheral wall of the piston rod; a hollow inner wall within the housing along which the piston rod moves up and down; the housing is provided with a supply passage that supplies compressed gas to the inside of the hollow inner wall, a discharge passage that discharges the compressed gas supplied to the inside of the hollow inner wall to the atmosphere, and a pressure loss passage that allows the compressed gas supplied to the inside of the hollow inner wall to pass with a larger pressure loss than through the supply passage and the discharge passage and is in communication with the discharge passage, The hollow inner wall of the housing has a sliding surface area having an inner diameter such that the sealing function can be effectively performed when the seal member abuts against the sliding surface area, and a loose insertion area having an inner diameter large enough that the sealing function of the seal member does not work at all, and one loose insertion area is sandwiched between two sliding surface areas from above and below, and further, the two sliding surface areas are sandwiched between two loose insertion areas above and below the sliding surface areas, Each of the supply passage, the discharge passage, and the pressure loss passage is connected to one of the separate loose insertion areas, and the loose insertion area to which the supply passage is connected is vertically adjacent to the loose insertion area to which the supply passage is connected, The present invention is characterized in that, during the process in which the piston rod moves up and down, when one of the seal members is positioned at the position of either the upper or lower sliding surface area, the other seal member is positioned at the position of either the loose insertion area.

[0008] In addition, the present invention provides a cylinder device having a piston that moves up and down within a housing by pressure fluid, A piston rod fixed to the piston; a seal member attached to a seal groove on an outer peripheral wall of the piston rod; a hollow inner wall within the housing along which the piston rod moves up and down; an annular valve member fitted onto the piston rod; The housing is provided with a supply passage for supplying compressed gas to the inside of the hollow inner wall, and a discharge passage for discharging the compressed gas supplied to the inside of the hollow inner wall to the atmosphere, A protrusion is provided below the seal groove of the piston rod to push down the annular valve member, a sliding surface area having an inner diameter such that the seal member abuts against the sliding surface area and the seal function effectively works; a loose insertion area having an inner diameter so large that the seal function of the seal member does not work at all; and a valve member area having an inner diameter large enough to allow the annular valve member to move up and down, the upper side of which is surrounded by a ring surface to accommodate the annular valve member and which communicates with the discharge passage, the sliding surface area, the loose insertion area, and the valve member area being successively provided one above the other; The present invention is characterized in that, as the piston rod moves up and down, the sealing member is located at the upper position of the sliding surface area, the sealing member is located at the position of the loose insertion area, and the protrusion is located at a position where it pushes down the annular valve member along with it. Effect of the Invention

[0009] According to the present invention, the position of the output member can be detected in three stages by utilizing the outer periphery of the piston rod and the inner wall of the housing, so that the cylinder device can be made more compact. [Brief description of the drawings]

[0010] [Figure 1] 1A shows a cylinder device according to a first embodiment of the present invention, in which FIG. 1A is a cross-section in an unclamped state, FIG. 1B is a cross-section of a housing, FIG. 1C is a cross-section of an output member 6, and FIG. 1D is a perspective view of a clamp rod. [Diagram 2] 2A shows a cylinder device according to a first embodiment, with FIG. 2A being a cross-sectional view in a clamped state and FIG. 2B being an enlarged view of an annular valve member. [Diagram 3] FIG. 2 is a cross-sectional view (clamped state) of the cylinder device of the first embodiment. [Figure 4] 4A shows a cross-sectional view of a second embodiment of the present invention, in which FIG. 4A shows an unclamped state, FIG. 4B shows a clamped state, and FIG. 4C shows a cross-sectional view of the clamped state. [Diagram 5] 5A shows a cross-sectional view of a third embodiment of the present invention, in which FIG. 5A shows an unclamped state, FIG. 5B shows a clamped state, and FIG. 5C shows a cross-sectional view of the clamped state. [Figure 6] 6A shows a fourth embodiment of the present invention, with FIG. 6A showing an unclamped state, FIG. 6B showing a clamped state, and FIG. 6C showing a cross-sectional view of the clamped state. [Figure 7] 7A shows a fifth embodiment of the present invention, with FIG. 7A showing an unclamped state, FIG. 7B showing a clamped state, and FIG. 7C showing a cross-sectional view of the clamped state. [Figure 8] 8A shows a sixth embodiment of the present invention, with FIG. 8A showing an unclamped state, FIG. 8B showing a clamped state, and FIG. 8C showing a cross-sectional view of the clamped state. BEST MODE FOR CARRYING OUT THEINVENTION

[0011] The overall structure of the cylinder device will be described. The cylinder device has a housing and an output member. The output member has a piston rod that moves up and down inside the hollow inner wall of the housing, a clamp rod driven by the piston rod, and a gripping member. The direction in which the piston rod moves up and down is called the direction of axis c, and when we say "up" or "down," we do not mean the direction of gravity. The direction in which the output member is pulled into the housing in the direction of axis c is called "down," and the direction in which it is extended from the housing is called "up." The piston, piston rod, and clamp rod are collectively called the output member.

[0012] The cylinder device of the present invention uses compressed gas to detect the position of the output member in three stages. The compressed gas is supplied to the cylinder device through a system separate from the pressure fluid that moves the output member up and down. Air, nitrogen gas, etc. can be used as the compressed gas. The housing is provided with a passage for supplying the compressed gas and a passage for discharging the compressed gas to the atmosphere. The two passages are referred to as a supply passage and a discharge passage. The supply passage and the discharge passage are connected via the hollow inside the housing and between the piston rod, and the supply passage and the discharge passage are in a closed, partially closed, or open state depending on the vertical position of the piston rod. The vertical position of the piston rod is detected by measuring the pressure of the passage that supplies the compressed gas.

[0013] When the supply passage and the exhaust passage are closed, there is no leakage of compressed gas, and the pressure measurement results in "high pressure." When the supply passage and the exhaust passage are moderately closed, compressed gas leaks moderately, and the pressure measurement results in "medium pressure." When the supply passage and the exhaust passage are open, compressed gas is released to the atmosphere, and the pressure measurement results in "low pressure." Note that "low pressure" can be defined as "low pressure" when the pressure detected by the pressure sensor is equal to or lower than a first threshold, "high pressure" when the pressure is equal to or higher than a second threshold that is higher than the first threshold, and "medium pressure" when the pressure is between the first threshold and the second threshold. A first threshold and a second threshold may be set for one pressure sensor. Two pressure sensors may be provided in one passage. When two pressure sensors are provided, the first threshold may be set for one pressure sensor, and the second threshold may be set for the other pressure sensor. If the pressure sensor acquires pressure values ​​as numerical values, a first threshold value and a second threshold value may be set in the comparator to classify the output of the pressure sensor into "high pressure," "medium pressure," and "low pressure."

[0014] The outer wall structure of the piston rod and the hollow inner wall structure of the housing are what change the state between closed, partially closed, and open. Also, an annular valve member is used as necessary. The annular valve member is a member that moves between the hollow inner wall of the housing and the outer wall of the piston rod, separate from the piston. Also, the combination of these is selected depending on what pressure is to be detected when the piston rod is in the raised position, intermediate position, and lowered position.

[0015] That is, at the time of the ascending position, it is necessary to be able to detect "high pressure", "medium pressure", or "low pressure". The same is true at the time of the intermediate position and the time of the descending position, and considering the permutation and combination, there are six patterns. These six patterns will be explained in Examples 1-6.

[0016] In addition, the outer peripheral wall of the piston rod and the hollow inner wall of the housing are formed by combining several compartments and regions in the vertical direction.

[0017] First, the outer peripheral wall of the piston rod has approximately the same diameter, but within a limited range of the outer peripheral wall of the piston rod, there are the following sections: 1) S seal section (hereinafter, the reference number "11" is used in each embodiment) in which a seal member is attached around the entire circumference. An O-ring and a packing are used as the seal member. 2) A push section (see reference number "12") that pushes down the annular valve member as the piston rod descends. One or two of the S seal sections 11, or one of the S seal sections 11 and a push section 12 in combination, are mounted on the outer circumferential wall of the piston rod.

[0018] If we explain this by assuming that one of passages A and B is a supply passage to which compressed gas is supplied, and the other passage is a discharge passage open to the atmosphere, the regions of the hollow inner wall of the housing are as follows: 1) A sliding surface area having an inner diameter that allows the seal member of the piston rod to come into contact with the sliding surface area and effectively perform the sealing function (hereinafter, the reference number is commonly designated as "13" in each embodiment). Here, in the sliding surface area, in the range where the seal member does not come into contact with the sliding surface area, a gap is provided between the sliding surface area and the outer peripheral wall of the piston rod. 2) A loose insertion area having a large inner diameter such that the sealing function of the piston rod seal member does not function at all (ibid., reference number "14"). 3) A passage connection area in which the A passage is connected to the loose insertion area (ibid., reference number "15"). 4) B passage connection area in which the B passage is connected to the loose insertion area (ibid., reference number "16"). 5) A pressure loss passage connection region in which a pressure loss passage is connected to the loose insertion region (ibid., reference number "17"). The loose insertion region is connected to the B passage or the A passage via a pressure loss passage. Here, the pressure loss passage is a passage having a larger pressure loss than either the A passage or the B passage. Specifically, it can be narrowed by reducing the hole diameter or by inserting an obstacle. 6) A valve member region (reference numeral 18) having a large inner diameter and surrounded by a ring surface on the upper side, capable of accommodating an annular valve member. Here, the annular valve member can move up and down within the valve member region. The valve member region also communicates with the B passage. These are selectively combined and mounted on the hollow inner wall of the housing, with the loose insertion area being mounted as a part of the A passage connecting area, the B passage connecting area, and the pressure loss passage connecting area.

[0019] In addition, the annular valve member, which is applied as necessary, has a groove on its upper surface. When the upper surface of the annular valve member with the groove on its upper surface comes into surface contact with the ring surface on the upper side of the valve member region, a pressure loss passage is formed by the ring surface and the groove, and the pressure loss passage communicates with passage B. In the following embodiment, the description will be given assuming that the A passage is a supply passage and the B passage is a discharge passage. [Example 1]

[0020] 1 to 3 show a cylinder device 1 according to a first embodiment. The cylinder device 1 is a cylinder device in which the output member is at "high pressure" when in the raised position, at "medium pressure" when in an intermediate position, and at "low pressure" when in the lowered position.

[0021] 1B shows only the housing 2. The housing 2 is fixed to a table T serving as a stationary base. The housing 2 is hollow and tubular, and the hollow inner wall includes, from above, a collar portion 2a, a pressure detection portion 2b, and a cylinder portion 2c.

[0022] FIG. 1C shows only the output member 6. The output member 6 includes a piston 7, a piston rod 3, a clamp rod 4, and a pair of slider pieces 5 for gripping a workpiece. The piston rod 3 is cylindrical, and the piston 7 is fixed to the outer circumferential surface at the lower end. The piston 7 is inserted into the cylinder portion 2c. The clamp rod 4 is inserted into the hollow inner wall of the piston rod 3 from below and is stopped by the flange portion 3a provided on the inner edge of the upper end. A spacer 8 is inserted into the hollow portion from the lower side of the piston rod 3, and is fixed by a stop ring 8a so as not to fall out of the hollow portion. An S seal section 11 is provided on the outer periphery of the piston rod 3. In the S seal section 11, an O-ring is attached to the ring groove 11b as a seal member 11a. The seal member 11a seals the outer periphery of the piston rod 3 around one circumference.

[0023] In addition, a protrusion 12a is provided around the outer periphery below the S seal section 11. This protrusion 12a is a protrusion that pushes down the annular valve member 10, and the region where the protrusion 12a is provided is the push section 12. The regions of the piston rod 3 other than these two regions have roughly the same diameter, which is smaller than the outer diameter of the seal member 11a.

[0024] Fig. 1D shows a perspective view of the tip of the clamp rod 4. A cam portion 4a is provided at the tip of the clamp rod 4. The cam portion 4a has two inclined surfaces 4b on either side of the axis c, which slope downward toward the axis c. A number of seal members are disposed between the piston 7, piston rod 3, and spacer 8 to fill the gaps between these members.

[0025] 1A, the collar portion 2a of the housing 2 supports the output member 6 in the direction of the axis c so as to be movable up and down. The cylinder portion 2c accommodates a piston 7 so as to be movable up and down.

[0026] O-rings S1, S2 are disposed between the output member 6 and the housing 2 above and below to prevent leakage of compressed gas. The pressure detection unit 2b has, successively from above, an A passage connection region 15 communicating with the A passage Ap of the housing 2, a sliding surface region 13 having an inner diameter that can be sealed by the seal member 11a of the S seal section 11, a loose insertion region 14 having a large inner diameter that cannot be sealed by the seal member 11a of the S seal section 11, and a valve member region 18 having an inner diameter larger than the loose insertion region and within which the annular valve member 10 can slide. The upper ceiling surface of the valve member region 18 is the ring surface 2d.

[0027] The annular valve member 10 is slidable up and down on the outer circumference of the piston rod 3 below the push section 12, and a groove 10b is provided on the upper surface 10a of the annular valve member 10 (see FIG. 2B). The groove 10b is provided in a part of the upper surface 10a of the annular valve member 10 in the radial direction of the axis c. When the upper surface 10a of the annular valve member 10 and the ring surface 2d are in surface contact with each other, a pressure loss passage with a large pressure loss is formed by the groove 10b and the ring surface 2d. When the upper surface 10a of the annular valve member 10 and the ring surface 2d are in surface contact with each other, the valve member region 18 communicates with the B passage Bp only through the pressure loss passage formed by the groove 10b. When the annular valve member 10 descends, the gap between the upper surface 10a of the annular valve member 10 and the ring surface 2d opens, and the pressure loss passage cannot be maintained.

[0028] A mount 9 is provided on the upper end side of the housing 2. The mount has a seating surface 9a on which a workpiece is placed, and a guide portion 9b that guides the slider piece 5 in the radial direction of the axis c. A packing 9c is disposed between the outer periphery of the slider piece 5 and the mount 9 to prevent the intrusion of dust. A cap 9d is placed on the upper side of the mount 9 as necessary.

[0029] Next, we will explain the path of the pressure fluid that moves the output member 6 up and down. The pressure fluid on the clamping side is supplied to the upper side of the piston 7 via path Th1 in the table T and path Hh in the housing 2. The space above the piston 7 is a clamp chamber CL into which the pressure fluid flows when the cylinder device 1 clamps a workpiece, and is surrounded by the upper surface of the piston 7, the cylinder portion 2c, and the lower surface of the annular valve member 10.

[0030] When the cylinder device 1 unclamps the workpiece, pressurized fluid is supplied to the underside of the piston 7 through a path Th2 of the table T. An unclamping chamber UC is surrounded by the underside of the piston 7, the cylinder portion 2c, the lower surface of the piston rod 3, and the lower surface of the spacer 8.

[0031] The clamping operation of the cylinder device will now be described. The cylinder device 1 shown in Fig. 1A is in an unclamped state. The pressure fluid is discharged from the clamp chamber CL, and the pressure fluid is supplied to the unclamped chamber UC via the path Th2. The output member 6 is in the raised position.

[0032] The cylinder device 1 shown in FIG. 2A is in a clamped state. A gripping hole WH is drilled in the workpiece W. The slider piece 5 is inserted into the gripping hole WH. When switching to the clamped state, pressurized fluid is supplied to the clamp chamber CL via paths Th1 and Hh, and pressure fluid is discharged from the unclamping chamber UC via path Th2. When the output member 6 descends, the cam surface 5a provided at the tip of the clamp rod 4 pushes the slider piece 5 in the radial direction of the axis c, and grips it from the inside of the gripping hole WH. When switching from the clamped state to the unclamping state, pressure fluid is supplied to the unclamping chamber UC, and pressure fluid in the clamping chamber CL is discharged.

[0033] The cylinder device 1 shown in Fig. 3 is in a clamped state, but for some reason, the output member 6 is in an overstroke state where it has descended too far. For example, this may occur when the size of the gripping hole WH is too large, or when the slider piece 5 has worn down to a small diameter. In such a case, the cylinder device 1 is in a clamped state, but in reality, the workpiece W is not gripped accurately.

[0034] Next, the compressed gas path for detecting the position of the output member 6 will be described. The compressed gas path Tp from the table T communicates with the path Hp of the housing 2 and branches into two paths, a path Mp to the mount portion 9 and a path A Ap. The path to the mount portion 9 is open to the atmosphere. The path A Ap is connected to the A path connection area 15 of the pressure detection portion 2b.

[0035] Detection of the position of the output member 6 using compressed gas will now be described. In the drawings, the path through which the compressed gas flows is marked with light ink. In FIG. 1, the compressed gas is released to the atmosphere through the path Mp of the mount unit 9. Therefore, when the pressure of the compressed gas is measured at a position where the compressed gas is supplied (not shown), it is in a low pressure state. When the workpiece W is mounted on the cylinder device 1 of FIG. 1, the path Mp of the mount unit 9 is blocked by the workpiece W. On the other hand, the S seal section 11 is located at the sliding surface area 13 and the sealing function is working. Therefore, there is no outlet for the compressed gas at the end of the A passage Ap. Therefore, the pressure of the compressed gas in the A passage Ap is maintained. If the pressure is measured at the position where the compressed gas is supplied, high pressure is detected and it is possible to determine whether the workpiece W is mounted or not. This state is an unclamped state. Note that if the workpiece W is mounted at an angle, the workpiece W is not in close contact with the seating surface 9a, and the compressed gas will leak. In this case, it can also be determined that the workpiece W is not mounted properly.

[0036] In Fig. 2, when the output member 6 is moved downward by the pressure fluid, the S seal section 11 leaves the sliding surface area 13, the seal member no longer functions, and the compressed gas is supplied to the loose insertion area 14 and the valve member area 18. The supplied compressed gas passes through a pressure loss passage formed by the groove 10b and the ring surface 2d, and is released to the atmosphere from the B passage Bp. Therefore, when the pressure of the compressed gas is measured from the external compressed gas supply port, it is possible to detect a state in which the pressure is lowered due to the pressure loss passage, although the pressure is not as low as in the state in Fig. 1 in which the workpiece W is not mounted. When the pressure is measured at the position where the compressed gas is supplied, a medium pressure is detected, and it is possible to determine that the cylinder device 1 is in a clamping state in which the workpiece W is clamped.

[0037] In FIG. 3, when the output member 6 further descends, the protrusion 12a of the push section 12 below the S seal section 11 hits the annular valve member 10, causing the annular valve member 10 to descend. As a result, the gap between the upper surface 10a of the annular valve member 10 and the ring surface 2d widens. In this state, the path of the compressed gas to the B passage Bp is no longer only a pressure loss passage, but is open to the atmosphere. If the pressure is measured at the position where the compressed gas is supplied, low pressure is detected, and it can be determined that the output member 6 of the cylinder device 1 has descended too far and is in an overstroke state.

[0038] In this embodiment, a groove 10b is provided in the annular valve member 10, and by moving the annular valve member 10, the groove 10b cooperates with the ring surface 2d to form a pressure loss passage, and the upper surface 10a of the annular valve member 10 and the ring surface 2d separate, creating two cases: a case where medium pressure is detected and a case where low pressure is detected. In addition to this, a state where no compressed gas leaks can be detected, making it possible to detect three states.

[0039] In this embodiment, the compressed gas in table T is branched into two, one of which is supplied to mount section 9 and the other to pressure detection section 2b, but it is also possible to prepare two systems of compressed gas in table T and send one to mount section 9 and the other to pressure detection section 2b separately.

[0040] According to this embodiment, the position of the output member 6 can be detected in three stages by utilizing the outer periphery of the piston rod 3 and the inner wall of the housing 2, so that the cylinder device 1 can be made smaller. [Example 2]

[0041] FIG. 4 shows a cylinder device 20 according to a second embodiment. The cylinder device 20 is a cylinder device that has "high pressure" when the output member 6 is in the raised position, "low pressure" when it is in the intermediate position, and "medium pressure" when it is in the lowered position.

[0042] The difference from Example 1 is the structure of the piston rod of the output member 6 and the pressure detection portion of the housing. The pressure detection portion 2b in Example 1 has, from the top, the A passage connection region 15, the sliding surface region 13, the loose insertion region 14, and the valve member region 18, but the pressure detection portion 2b in Example 2 has, from the top, the A passage connection region 15, the upper sliding surface region 13, the pressure loss passage connection region 17, the lower sliding surface region 13, and the B passage connection region 16, and does not have the valve member region 18. The pressure loss passage connection region 17 is provided with a pressure loss passage Np that communicates with the B passage Bp.

[0043] Moreover, in the second embodiment, there is no valve member region and no annular valve member 10, but instead the portion corresponding to the annular valve member 10 is part of the housing 2, and the housing 2 and the piston rod 3 are directly sealed by an O-ring S3. Therefore, the O-rings S1 and S3 above and below the pressure detection portion 2b prevent the compressed gas from leaking into the atmosphere or the clamp chamber CL. No push section 12 is provided on the outer periphery of the piston rod 3 in the second embodiment, and only one S seal section 11 is provided.

[0044] In addition, in the first embodiment, one line of compressed gas in the table T is branched into two, one of which is supplied to the mount portion 9 and the other to the pressure detection portion 2b, but in this embodiment, two lines of compressed gas are prepared in the table T, one of which is sent to the mount portion 9 and the other to the A passage Ap. However, in Fig. 4, the passage on the table T side that sends the compressed gas to the A passage Ap is not shown. The above are the differences from the cylinder device 1 in the first embodiment, and since the other configurations are the same, explanations will be omitted.

[0045] Next, the operation of the cylinder device 20 will be described. In the unclamped state of Fig. 4A, the seal member 11a of the S seal section 11 of the piston rod 3 is located in the upper sliding surface area 13. The compressed gas is sealed in this sliding surface area 13 and cannot leak into the pressure loss passage connection area 17 continuing downward. Therefore, if the pressure at the supply position of the compressed gas to the A passage Ap is measured, high pressure can be detected.

[0046] In the clamped state of Fig. 4B, the output member 6 descends and is released from the upper sliding surface area 13. The seal of the S seal section 11 does not function, and the upper sliding surface area 13 communicates with the pressure loss passage connecting area 17, the lower sliding surface area 13, and the B passage connecting area 16. The pressure loss passage connecting area 17 communicates with the B passage Bp via the pressure loss passage Np. In addition, the compressed gas communicates with the passage connecting area 16 via the lower sliding surface area 13. Therefore, low pressure can be detected by measuring the pressure at the supply position of the compressed gas.

[0047] 4C, the output member 6 further descends, and the S seal section 11 reaches the lower sliding surface area 13 and exerts a sealing function. As a result, the compressed gas cannot pass through the lower sliding surface area 13, but only passes through the pressure loss passage connection area 17. Therefore, by measuring the pressure at the supply position of the compressed gas, the medium pressure due to the pressure loss passage Np can be detected.

[0048] [Example 3] 5 shows a cylinder device 30 of Example 3. The cylinder device is a cylinder device in which the output member 6 has "medium pressure" when in the raised position, "high pressure" when in an intermediate position, and "low pressure" when in the lowered position.

[0049] The difference from Example 1 is the structure of the piston rod 3 of the output member 6 and the pressure sensing portion 2b of the housing 2. The pressure sensing portion 2b of Example 3 has, from the top, a B passage connecting region 16, a sliding surface region 13, an A passage connecting region 15, a sliding surface region 13, and a pressure loss passage connecting region 17, and unlike Example 1, does not have a valve member region 18, nor does it have an annular valve member 10. Instead, the portion corresponding to the annular valve member 10 is part of the housing 2.

[0050] Moreover, the piston rod 3 of the third embodiment does not have the push section 12 of the first embodiment on its outer periphery, but has two upper and lower S seal sections 11. The distance between the two S seal sections 11 is determined so that each of the two S seal sections 11 can simultaneously perform a sealing function with the upper and lower sliding surface areas 13. In other words, the two S seal sections 11 that perform the sealing function sandwich the A passage connection area 15, thereby blocking the compressed gas in the A passage Ap. The above are the differences from the cylinder device 1 of the first embodiment, and the other configurations are the same, so explanations will be omitted.

[0051] Next, the operation of the cylinder device 20 will be described. 5A, the upper S seal section 11 is present in the B passage connection region 16, and the lower S seal section 11 is present in the upper sliding surface region 13. Therefore, the A passage connection region 15, the lower sliding surface region 13, and the pressure loss passage connection region 17 are in communication. Therefore, if the pressure is measured at the supply position of the compressed gas, the medium pressure due to the pressure loss passage Np can be detected.

[0052] 5B, the output member 6 is lowered, and the A passage connection region 15 is sandwiched between two S seal sections 11, each of which is present in the upper and lower sliding surface regions 13. Therefore, by measuring the pressure at the supply port of the compressed gas, high pressure can be detected.

[0053] 5C, the output member 6 is further lowered, and the upper S seal section 11 is present in the lower sliding surface area 13. Therefore, the A passage connection area 15, the upper sliding surface area 13, and the B passage connection area 16 are in communication. Therefore, if the pressure is measured at the supply port of the compressed gas, low pressure can be detected.

[0054] [Example 4] 6 shows a cylinder device 40 of Example 4. The cylinder device 40 is a cylinder device that has "medium pressure" when the output member 6 is in the raised position, "low pressure" when the output member 6 is in the intermediate position, and "high pressure" when the output member 6 is in the lowered position.

[0055] The difference from Example 1 is the structure of the piston rod 3 of the output member 6 and the pressure sensing portion 2b of the housing 2. The pressure sensing portion 2b of Example 4 has, from the top, an A passage connecting region 15, a sliding surface region 13, a pressure loss passage connecting region 17, a sliding surface region 13, and a B passage connecting region 16, and unlike Example 1, does not have a valve member region 18, nor does it have an annular valve member 10. Instead, in Example 4, the portion corresponding to the annular valve member 10 is part of the housing 2.

[0056] Moreover, the outer periphery of the piston rod 3 of Example 4 does not have the push section 12 of Example 1, but has two upper and lower S seal sections 11. The distance between the two S seal sections 11 is determined so that they do not simultaneously exert a sealing function between the upper and lower sliding surface areas 13. The above is the difference from the cylinder device 1 of Example 1, and since the other configurations are the same, explanations will be omitted.

[0057] 6A, the seal member 11a of the lower S seal section 11 is present in the upper sliding surface area 13. Therefore, only the B passage connection area 16 is separated from the other areas, and the A passage connection area 15, the lower sliding surface area 13, and the pressure loss passage connection area 17 are in communication. If the pressure is measured at the supply port of the compressed gas, the medium pressure due to the pressure loss passage Np can be detected.

[0058] 6B, the output member 6 is lowered, and the seal member 11a of the upper S seal section 11 is present in the A passage connection region 15, and the seal member 11a of the lower S seal section 11 is present in the B passage connection region 16. Therefore, the A passage connection region 15, the pressure loss passage connection region 17, and the B passage connection region 16 are in a communication state. Therefore, if the pressure is measured at the supply port of the compressed gas, low pressure can be detected.

[0059] In the clamped state of Fig. 6C, the output member 6 is further lowered, and the seal member 11a of the upper S seal section 11 is present in the upper sliding surface area 13. Only the A passage connection area 15 is separated from the other areas. Therefore, if the pressure at the compressed gas supply port is measured, high pressure can be detected.

[0060] [Example 5] 7 shows a cylinder device 50 of Example 5. The cylinder device is a cylinder device in which the output member 6 has "low pressure" when in the raised position, "high pressure" when in an intermediate position, and "medium pressure" when in the lowered position.

[0061] The difference from Example 1 is the structure of the piston rod 3 of the output member 6 and the pressure sensing portion 2b of the housing 2. The pressure sensing portion 2b of Example 5 has, from the top, a pressure loss passage connecting region 17, a sliding surface region 13, an A passage connecting region 15, a sliding surface region 13, and a B passage connecting region 16, and unlike Example 1, does not have a valve member region 18 or an annular valve member 10. Instead, in Example 5, the portion corresponding to the annular valve member 10 is part of the housing 2.

[0062] On the other hand, the outer periphery of the piston rod 3 of the fifth embodiment does not have the push section 12 of the first embodiment, but has two upper and lower S seal sections 11. The spacing is determined so that the two upper and lower S seal sections 11 can simultaneously perform a sealing function with the upper and lower sliding surface areas 13, respectively. In other words, the A passage connection area 15 is sandwiched between the two S seal sections 11, thereby blocking the compressed gas in the A passage Ap. The above are the differences from the cylinder device 1 of the first embodiment, and since the other configurations are the same, explanations will be omitted.

[0063] Next, the operation of the cylinder device 50 will be described. In the unclamped state of Fig. 7A, the lower S seal section 11 is present in the upper sliding surface area 13. Therefore, the pressure loss passage connection area 17 is isolated from the other areas, while the A passage connection area 15, the lower sliding surface area 13, and the B passage connection area 16 are in communication. Therefore, if the pressure is measured at the supply port of the compressed gas, low pressure can be detected.

[0064] In the clamped state of Fig. 7B, the output member 6 is lowered and the A passage connection region 15 is sandwiched between the two S seal sections 11. The compressed gas cannot leak from the A passage connection region 15. Therefore, if the pressure at the supply port of the compressed gas is measured, a high pressure can be detected.

[0065] 7C, the output member 6 is further lowered, and the upper S seal section 11 is present in the lower sliding surface area 13. Therefore, the A passage connection area 15, the sliding surface area 13, and the pressure loss passage connection area 17 are in communication. Therefore, by measuring the pressure at the supply port of the compressed gas, the medium pressure due to the pressure loss passage Np can be detected.

[0066] [Example 6] 8 shows a cylinder device 60 of Example 6. The cylinder device 60 is a cylinder device in which the output member 6 has "low pressure" when in the raised position, "medium pressure" when in the intermediate position, and "high pressure" when in the lowered position.

[0067] The difference from Example 1 is the structure of the piston rod 3 of the output member 6 and the pressure sensing portion 2b of the housing 2. The pressure sensing portion 2b of Example 6 has, from the top, an A passage connecting region 15, a sliding surface region 13, a pressure loss passage connecting region 17, a sliding surface region 13, and a B passage connecting region 16. Unlike Example 1, it does not have a valve member region 18, nor does it have an annular valve member 10. Instead, in Example 6, the portion corresponding to the annular valve member 10 is part of the housing 2.

[0068] The piston rod 3 of the sixth embodiment does not have the push section 12 of the first embodiment on its outer periphery, but has two upper and lower S seal sections 11. The distance between the two S seal sections 11 is determined so that they do not simultaneously exert a sealing function between the upper and lower sliding surface areas 13. The above is the difference from the cylinder device 1 of the first embodiment, and the other configurations are the same, so the explanation will be omitted.

[0069] In the unclamped state of Fig. 8A, the seal member 11a of the upper S seal section 11 is present in the A passage connection area 15, and the seal member 11a of the lower S seal section 11 is present in the pressure loss passage connection area 17. Therefore, the A passage connection area 15, the sliding surface area 13, and the B passage connection area 16 are in communication. Therefore, if the pressure is measured at the supply port of the compressed gas, low pressure can be detected.

[0070] 8B, the output member 6 is lowered, and the seal member 11a of the lower S seal section 11 is present in the lower sliding surface area 13. The seal member 11a of the upper S seal section 11 is present in the A passage connection area 15. Therefore, only the B passage connection area 16 is separated from the other areas, and the medium pressure due to the pressure loss passage Np can be detected by measuring the pressure at the supply port of the compressed gas.

[0071] 8C, the output member 6 is further lowered, and the seal member 11a of the upper S seal section 11 is present in the upper sliding surface area 13. Therefore, the A passage connection area 15 is separated from the other areas, and therefore, if the pressure at the supply port of the compressed gas is measured, a high pressure can be detected.

[0072] Unlike Example 1, Example 6 does not have the valve member region 18, nor does it have the annular valve member 10. It is also possible to achieve the states of "high pressure" at the raised position, "medium pressure" at the intermediate position, and "low pressure" at the lowered position of Example 1 without utilizing the valve member region 18 and the annular valve member 10.

[0073] [Example 7] The seventh embodiment is realized without using the valve member region 18 and the annular valve member 10. In this case, the pressure sensing portion 2b is made up of, from the top, the A passage connecting region 15, the sliding surface region 13, the pressure loss passage connecting region 17, the sliding surface region 13, and the B passage connecting region 16. In addition, one S seal section 11 is provided on the outer periphery of the piston rod 3.

[0074] In the unclamped state, high pressure can be detected by having the S seal section 11 present in the upper sliding surface area 13 and isolating only the A passage connection area 15 from the other areas.

[0075] Next, when the output member is lowered, the S seal section 11 is placed in the lower sliding surface area 13, thereby communicating the A passage connection area 15, the upper sliding surface area 13, and the pressure loss passage connection area 17. This makes it possible to detect the medium pressure through the pressure loss passage Np.

[0076] Then, when the output member 6 further descends, the S seal section 11 is made to be present in the B passage connection region 16. The A passage connection region 15, the upper sliding surface region 13, the pressure loss passage connection region 17, the lower sliding surface region 13, and the B passage connection region 16 are in communication with each other. Therefore, by measuring the pressure at the supply port of the compressed gas, low pressure can be detected.

[0077] In this way, the cost of the cylinder assembly can be reduced since the valve member region 18 and the annular valve member 10 are not utilized.

[0078] According to Example 2-7, the housing 2 is provided with a supply passage (A passage Ap) that supplies compressed gas to the inside of the position detection unit 2b (hollow inner wall of the housing 2), a discharge passage (B passage Bp) that discharges the compressed gas supplied to the inside of the position detection unit 2b to the atmosphere, and a pressure loss passage Np that passes the compressed gas supplied to the inside of the position detection unit 2b with a larger pressure loss than the supply passage (A passage Ap) and the discharge passage (B passage Bp) and communicates with the discharge passage (B passage Bp). The position detection unit 2b is provided with a sliding surface area 13 having an inner diameter that allows the seal member 11a to come into contact with and effectively function as a seal, and a loose insertion area 14 having a large inner diameter that does not allow the seal member 11a to function as a seal at all.

[0079] In these embodiments, the loose insertion area 14 is part of the A passage connection area 15, the B passage connection area 16, and the pressure loss passage connection area 17, so that one loose insertion area 14 is sandwiched between two sliding surface areas 13 from above and below, and further sandwiched between two loose insertion areas 14 above and below these two sliding surface areas 13, respectively.

[0080] Examples 2 and 7 are examples (hereinafter, Type 1) in which one seal member 11a is provided on the piston rod 3. Examples 3 and 5 are a first example (hereinafter, Type 2) in which two seal members 11a are provided on the piston rod 3. Examples 4 and 6 are a second example (hereinafter, Type 3) in which two seal members 11a are provided on the piston rod 3.

[0081] In the example of Type 2, the upper and lower seal members 11a are adapted to be positioned simultaneously at the positions of the upper and lower sliding surface regions 13, respectively.

[0082] In the example of Type 3, when one seal member 11a is positioned at either the upper or lower sliding surface region 13 during the process of the piston rod 3 moving up and down, the other seal member 11a is installed so as to be positioned at either the loose insertion region 14 (A passage connection region 15, B passage connection region 16, pressure loss passage connection region 17).

[0083] In any of types 1 to 3, the A passage connection region 15 and the pressure loss passage connection region 17 are adjacent to each other. When one (type 1) or two (types 2 and 3) seal members 11a cooperate with either the upper or lower sliding surface region 13 or the upper and lower sliding surface regions 13 to exhibit a sealing function and isolate the A passage connection region 15 from other passages, the detected pressure of the compressed gas is "high pressure." When one seal member 11a cooperates with either the upper or lower sliding surface region 13 to exhibit a sealing function and isolates the B passage connection region 16 with the A passage connection region 15 and the pressure loss passage connection region 17 in a communicating state, the detected pressure of the compressed gas is "medium pressure." When one seal member 11a cooperates with either the upper or lower sliding surface area 13 to perform a sealing function and the A passage connection area 15 and the B passage connection area 16 are in communication to isolate the pressure loss passage connection area 17, or when the upper and lower seal members 11a do not cooperate with either the upper or lower sliding surface area 13 and do not perform a sealing function, the detected pressure of the compressed gas becomes "low pressure."

[0084] When the A passage connection region 15 is a supply passage that supplies compressed gas, the A passage connection region 15 and the pressure loss passage connection region 17 may be arranged in any vertical arrangement, except that the A passage connection region 15 and the pressure loss passage connection region 17 are adjacent to each other. When the B passage connection region 16 is a supply passage that supplies compressed gas, the A passage connection region 15, the B passage connection region 16 and the pressure loss passage connection region 17 may be arranged in any vertical arrangement, except that the B passage connection region 16 and the pressure loss passage connection region 17 are adjacent to each other. In addition, whether the position where the seal member 11a exists in the sliding surface region 13 is the upper or lower end position, or the position where the seal member 11a exists in the loose insertion region 14 (either the A passage connection region 15, the B passage connection region 16 or the pressure loss passage connection region 17) is the upper or lower end position, may be selected so that the three conditions of "high pressure", "medium pressure" and "low pressure" can be detected. For example, in the fourth embodiment and the sixth embodiment, the A passage connection region 15, the B passage connection region 16, and the pressure loss passage connection region 17 are arranged in the same vertical order, but the lower seal member 11a has the lower sliding surface region 13 as its upper limit position in the fourth embodiment, whereas the lower seal member 11a has the loose insertion region 14 (pressure loss passage connection region 17) as its upper limit position in the sixth embodiment. As a result, the order in which the three conditions of "high pressure", "medium pressure", and "low pressure" occur in relation to the position of the piston rod 3 is different.

[0085] In the above embodiment, the pressure loss passage connection region 17 is shown to be connected only to the B passage Bp via the pressure loss passage Np, but it may also be connected to the A passage Ap. Also, although the A passage Ap is described as a supply passage and the B passage Bp is described as a discharge passage, the A passage Ap may also be a discharge passage and the B passage Bp a supply passage. Also, the pressurized fluid that moves the output member 6 up and down may be a liquid such as hydraulic pressure or water, or a gas such as air or nitrogen. [Explanation of symbols]

[0086] 1, 20, 30, 40, 50, 60 Cylinder device 2. Housing 2a Color section 2b Pressure detection section 2c Cylinder section 2d ring surface 3 Piston rod 3a Tsuba 4 Clamp rod 4a Cam section 4b Slope 5 Slider piece 5a Cam surface 6 Output member 7 Piston 8 Spacer 8a Stop ring 9 Mounting section 9a Seating surface 9b Information Department 9c Gasket 9d Cap 10 Annular valve member 10a top surface 10b groove 11 S seal section 11a Sealing material 11b Ring groove 12 Push Section 12a Protrusion 13 Sliding surface area 14 Free insertion area 15 A passage connection area 16 B Passage Connection Area 17 Pressure loss passage connection area 18 Valve member area

Claims

1. In a cylinder device having a piston that moves up and down by a pressure fluid inside a housing, a piston rod fixed to the piston, a seal member attached to a seal groove on the outer peripheral wall of the piston rod, and a hollow inner wall inside the housing where the piston rod moves up and down, the housing is provided with a supply passage for supplying compressed gas inside the hollow inner wall, a discharge passage for discharging the compressed gas supplied inside the hollow inner wall to the atmosphere, and a pressure loss passage for passing the compressed gas supplied inside the hollow inner wall with a pressure loss greater than that of the supply passage and the discharge passage and communicating with the discharge passage. The hollow inner wall inside the housing has a sliding surface region having an inner diameter such that the seal member abuts and the sealing function works effectively, and a free insertion region having a large inner diameter such that the sealing function of the seal member does not work at all. One free insertion region is sandwiched vertically by two sliding surface regions, and further, free insertion regions are respectively sandwiched above and below the two sliding surface regions. Each of the supply passage, the discharge passage, and the pressure loss passage is connected to one of the separate free insertion regions, and the free insertion region to which the supply passage or the discharge passage is connected is vertically adjacent to the free insertion region to which the pressure loss passage is connected. A cylinder device characterized by this.

2. In a cylinder device having a piston that moves up and down by a pressure fluid inside a housing, a piston rod fixed to the piston, seal members attached to seal grooves spaced apart vertically on the outer peripheral wall of the piston rod, and a hollow inner wall inside the housing where the piston rod moves up and down, the housing is provided with a supply passage for supplying compressed gas inside the hollow inner wall, a discharge passage for discharging the compressed gas supplied inside the hollow inner wall to the atmosphere, and a pressure loss passage for passing the compressed gas supplied inside the hollow inner wall with a pressure loss greater than that of the supply passage and the discharge passage and communicating with the discharge passage. The hollow inner wall inside the housing has a sliding surface region having an inner diameter such that the seal member abuts and the sealing function works effectively, and a free insertion region having a large inner diameter such that the sealing function of the seal member does not work at all. One free insertion region is sandwiched vertically by two sliding surface regions, and further, free insertion regions are respectively sandwiched above and below the two sliding surface regions. Each of the supply passage, the discharge passage, and the pressure loss passage is connected to one of the separate insertion regions, and the insertion region to which the supply passage or the discharge passage is connected is vertically adjacent to the insertion region to which the pressure loss passage is connected. A cylinder device, characterized in that, in the process of the piston rod moving up and down, the upper and lower seal members are attached so as to be simultaneously positioned at the positions of the upper and lower sliding surface regions respectively. **Claim 3** In a cylinder device having a piston that moves up and down by a pressure fluid inside a housing, a piston rod fixed to the piston, seal members attached to respective seal grooves spaced apart vertically on the outer peripheral wall of the piston rod, and a hollow inner wall inside the housing where the piston rod moves up and down, the housing is provided with a supply passage for supplying compressed gas to the inside of the hollow inner wall, a discharge passage for discharging the compressed gas supplied to the inside of the hollow inner wall to the atmosphere, and a pressure loss passage for passing the compressed gas supplied to the inside of the hollow inner wall with a pressure loss larger than that of the supply passage and the discharge passage and communicating with the discharge passage. The hollow inner wall inside the housing has a sliding surface region having an inner diameter such that the seal member abuts thereon and the sealing function works effectively, and an insertion region having a large inner diameter such that the sealing function of the seal member does not work at all. One insertion region is sandwiched vertically by two sliding surface regions, and further, insertion regions are provided so as to sandwich the upper and lower sides of the two sliding surface regions respectively. Each of the supply passage, the discharge passage, and the pressure loss passage is connected to one of the separate insertion regions, and the insertion region to which the supply passage or the discharge passage is connected is vertically adjacent to the insertion region to which the pressure loss passage is connected. A cylinder device, characterized in that, in the process of the piston rod moving up and down, when one of the seal members is positioned at the position of one of the upper and lower sliding surface regions, the other seal member is attached so as to be positioned at the position of one of the insertion regions. **Claim 4** In a cylinder device having a piston that moves up and down by a pressure fluid inside a housing, a piston rod fixed to the piston, a seal member attached to a seal groove on the outer peripheral wall of the piston rod, a hollow inner wall inside the housing where the piston rod moves up and down, and an annular valve member externally inserted on the piston rod. The housing is provided with a supply passage for supplying compressed gas to the inside of the hollow inner wall and a discharge passage for discharging the compressed gas supplied to the inside of the hollow inner wall to the atmosphere. A protrusion is provided below the seal groove of the piston rod to pull and push down the annular valve member. On the hollow inner wall inside the housing, there are a sliding surface region having an inner diameter such that the seal member abuts and the sealing function works effectively, a free insertion region having a large inner diameter such that the sealing function of the seal member does not work at all, and a valve member region having a large inner diameter through which the annular valve member can move up and down, with the upper side surrounded by a ring surface to accommodate the annular valve member and communicating with the discharge passage. The sliding surface region, the free insertion region, and the valve member region are provided continuously up and down. A cylinder device, characterized in that in the process of the piston rod moving up and down, the seal member is provided at the position of the upper sliding surface region, the seal member is provided at the position of the free insertion region, and the protrusion is provided at the position where the protrusion pulls and pushes down the annular valve member.

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