JP2016223473A5 - - Google Patents

Description

Pull type clamp device

  The present invention relates to a pull-type clamp device in which a piston rod is driven to be clamped in a retracting direction by a tandem fluid pressure cylinder.

  In a clamping device driven by a fluid pressure cylinder, when the clamp driving force is strengthened, (a) a method of increasing the diameter of the fluid pressure cylinder, (b) a method of incorporating a booster mechanism, (c) arranged in series A system employing a plurality of fluid pressure cylinders (tandem fluid pressure cylinders) has been put to practical use.

  Regarding the clamp device or the fluid pressure cylinder that employs the method (c), the techniques described in Patent Document 1 and Patent Document 2 are known.

  The fluid pressure cylinder of Patent Document 1 is configured by arranging three double-acting fluid pressure cylinders in series on a common cylinder body. In this fluid pressure cylinder, three independent cylinder holes are formed in series in the cylinder body, and piston members are movably mounted in the three cylinder holes, respectively. The rod extends from one end of the cylinder body to the outside of the cylinder body, and fluid pressure working chambers are formed on both sides of the piston member in each cylinder hole. In each of the three cylinder holes, two fluid pressure ports that can supply / discharge fluid pressure from the outside to the two fluid pressure working chambers are formed in the cylinder body.

  In the fluid pressure cylinder of Patent Document 2, an outer piston is movably mounted in a large-diameter cylinder hole formed in the cylinder body, an outer rod extending from the outer piston to the tip side is fixed to the outer piston, and a small-diameter cylinder hole is formed in the outer rod. The tip of the small-diameter cylinder hole is closed with a rod cover, and an inner piston is mounted in the small-diameter cylinder hole so as to be relatively movable, and extends from the head side end wall of the cylinder body to the inner rod end that penetrates the outer piston. The piston is fixed, the first and second fluid pressure working chambers are formed on both sides of the outer piston, the third fluid pressure working chamber is formed on the tip side of the inner piston, and the inner tube is installed in the shaft hole inside the inner rod. It is installed.

  A first fluid pressure passage communicating from the first fluid pressure port formed in the cylinder body to the first fluid pressure working chamber, and a second fluid pressure port formed in the cylinder body through the outside of the inner tube in the inner rod, are second. A second fluid pressure passage communicating with the fluid pressure working chamber and a third fluid pressure passage communicating with the third fluid pressure working chamber from the first fluid pressure port through the inner tube are formed.

JP-A-6-323306 Japanese Patent Laid-Open No. 8-200235

  In the fluid pressure cylinder of Patent Document 1, a total of six fluid pressure ports are formed in the cylinder body, and the fluid pressure is supplied / discharged to / from the six fluid pressure ports by pipes and hoses outside the fluid pressure cylinder. Therefore, there is a problem that the fluid pressure supply system becomes complicated and the manufacturing cost becomes high, and the fluid pressure cylinder becomes large.

The fluid pressure cylinder of Patent Document 2, first, third fluid but by the fluid pressure supplied to the pressure operating chamber are possible and Turkey to drive the outer rod (output rod) the extending direction, the second fluid pressure operation chamber Since the outer rod is driven in the retracted direction with a fluid pressure of 1 mm, the driving force in the extending direction can be enhanced, but the driving force in the retracted direction cannot be enhanced. Therefore, even if the fluid pressure cylinder of Patent Document 2 is applied to a pull-type clamp device of a type that clamps the output rod in the retracting direction, the clamp driving force cannot be enhanced. Moreover, in the fluid pressure cylinder of Patent Document 2, the fluid pressure supply system becomes complicated, and the manufacturing cost becomes expensive.

  An object of the present invention is to provide a pull type clamp device in which a fluid pressure passage for supplying / exhausting fluid pressure to / from the first and second clamping fluid pressure working chambers is formed in a wall portion of a cylinder body.

2. The pull type clamp device according to claim 1, wherein the tandem type fluid pressure cylinder includes a cylinder main body, and the cylinder main body. First and second cylinder holes formed in series so as to line up in the retreat direction, and first and second piston portions movably mounted in the first and second cylinder holes, respectively. And a common piston rod fixed to the first and second piston portions and extending from the first piston portion side to the outside of the cylinder body. The cylinder body includes a cylinder hole forming wall portion and the cylinder hole forming wall. And a partition wall through which the piston rod penetrates while partitioning between the first and second cylinder holes and the first and second cylinder holes, The first and second clamping fluid pressure working chambers are respectively formed on the rod side end wall side with respect to the second piston portion, and the first and first fluid pressure ports are formed in the wall portion of the cylinder body from one common fluid pressure port. A fluid pressure passage for clamping capable of supplying fluid pressure to the fluid pressure working chamber for two clamps is formed , and the first unclamping fluid pressure on the partition wall side with respect to the first piston portion of the first cylinder hole. An operation chamber is formed, and an unclamping fluid pressure passage capable of supplying fluid pressure to the first unclamping fluid pressure operation chamber is formed in the wall portion of the cylinder body, and the cylinder body is formed at an end of the second cylinder hole. A second hydraulic pressure working chamber for unclamping is formed on the head side end wall side with respect to the second piston portion of the second cylinder hole, and the piston rod Inside the first and second ancra It is characterized in that the rod in the fluid pressure passage for communicating the fluid pressure operation chamber for flop is formed.

  The pull type clamp device according to claim 2 is characterized in that, in the invention of claim 1, the inner diameter of the second cylinder hole is formed larger than the inner diameter of the first cylinder hole and the outer diameter of the partition wall. .

Pull clamping apparatus of claim 3, in the invention of claim 1 or 2, that the plurality of steel balls and the plurality of steel balls disposed piston rod pivot mechanism having a plurality of helical grooves that people engage respectively It is a feature.

According to a fourth aspect of the present invention, there is provided the pull type clamp device according to the third aspect of the invention, wherein the plurality of steel balls are mounted on an inner peripheral wall portion of a piston rod through hole of the partition wall, and the plurality of spiral grooves are formed on an outer periphery of the piston rod. It is characterized by being formed in the part .

According to a fifth aspect of the present invention, in the pull type clamp device according to the first aspect of the invention, the partition wall is formed with a fluid pressure short-circuit passage that communicates the clamping fluid pressure passage with the first unclamping fluid pressure working chamber. The fluid pressure short circuit passage is provided with an on-off valve mechanism that opens only when the first piston part moves to the clamp side by a full stroke .

Since the present invention has the structure described in the column of problem solving means, the following effects can be obtained.
According to the first aspect of the present invention, a clamping fluid pressure passage capable of supplying fluid pressure from one common fluid pressure port to the first and second clamping fluid pressure working chambers is formed in the wall portion of the cylinder body. Therefore, the fluid pressure supply system for supplying fluid pressure to the fluid pressure working chambers for the first and second clamps can be simplified, the clamp device can be downsized, and the manufacturing cost can be reduced.
Since the piston rod can be driven in the retracted direction by the fluid pressure in the first and second fluid pressure working chambers, the driving force of the pull type clamp device can be enhanced.
Then, in order to form an unclamping fluid pressure passage capable of supplying fluid pressure to the first unclamping fluid pressure working chamber in the wall portion of the cylinder body, fluid pressure is supplied to the first unclamping fluid pressure working chamber. The fluid pressure supply system is simplified, the clamp device can be downsized, and the manufacturing cost can be reduced.
In addition to the first unclamping fluid pressure working chamber, the second unclamping fluid pressure working chamber is formed, so that the driving force for unclamping the piston rod in the extending direction can be enhanced.
Also, a fluid pressure supply system for supplying fluid pressure to the second unclamping fluid pressure working chamber to form a fluid pressure passage in the rod communicating with the first and second unclamping fluid pressure working chambers in the piston rod. Simplifies and becomes compact.

  According to the invention of claim 2, since it is not necessary to form a fluid pressure passage in the wall portion of the cylinder body on the outer peripheral side of the second cylinder hole, the second cylinder hole has a larger diameter than the first cylinder hole. Thus, the pressure receiving area of the second piston portion can be increased, and the clamp driving force can be enhanced.

  According to the invention of claim 3, when the piston rod is extended and retracted, the piston rod can be turned by the piston rod turning mechanism.

According to invention of Claim 4, it is with respect to the said partition wall through several steel ball and several spiral groove.
The piston rod can be turned.

According to the fifth aspect of the present invention, the on-off valve mechanism is opened only when the first piston portion is moved to the clamp side by a full stroke, and the clamping fluid pressure passage communicates with the first unclamping fluid pressure working chamber. Therefore, the fluid pressure in the clamping fluid pressure passage does not rise. Therefore, it is possible to detect that a normal clamping state (clamp failure) is not established from the fluid pressure in the clamping fluid pressure passage.

It is a longitudinal cross-sectional view of the pull type clamp apparatus (unclamped state) of Example 1 of this invention. It is a top view of the pull type clamp apparatus (unclamped state) of FIG. It is a longitudinal cross-sectional view of the pull type clamp apparatus (clamp state) of FIG. It is a longitudinal cross-sectional view of the pull type clamp apparatus (unclamped state) of Example 2. It is a longitudinal cross-sectional view of the pull type clamp apparatus (clamp state) of FIG. It is a longitudinal cross-sectional view of the pull type clamp apparatus (unclamped state) of Example 3. It is a longitudinal cross-sectional view of the pull type clamp apparatus (clamp state) of FIG. It is a longitudinal cross-sectional view of the pull type clamp apparatus (clamp state) of Example 4. It is an enlarged view of the A section of FIG. It is a longitudinal cross-sectional view of the pull type clamp device (clamp failure state) of FIG. It is an enlarged view of the B section of FIG.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

As shown in FIGS. 1 to 3, the pull-type clamp device 1 of the present application is a clamp device in which a piston rod 6 is clamped in a retracted direction by a tandem fluid pressure cylinder 2 having a vertical axis. .
The tandem fluid pressure cylinder 2 includes a cylinder body 3 having a vertical axis, first and second cylinder holes 4a and 4b formed in series in the cylinder body 3, and the first and second cylinders 3 and 4. The first and second piston portions 5a and 5b are movably mounted in the cylinder holes 4a and 4b, respectively, and are fixed to the first and second piston portions 5a and 5b and are attached to the outside of the cylinder body 3 from the first piston portion 5a side. And a common piston rod 6 extending to the end. In this embodiment, “fluid pressure” means pressurized fluid. Further, “hydraulic pressure (pressurized oil)” is employed as “fluid pressure”, but pressurized air may be employed.

The cylinder body 3 divides the cylinder hole forming wall 3a, the rod side end wall 3b integral with the cylinder hole forming wall 3a, and the first and second cylinder holes 4a and 4b, and the piston rod 6 A partition wall 7 that penetrates and a head side end wall 3d that closes an end of the second cylinder hole 4b are provided.
The inner diameter of the second cylinder hole 4 b is larger than the inner diameter of the first cylinder hole 4 a and the outer diameter of the partition wall 7.

  A rectangular installation wall 3c (including the rod-side end wall 3b) having a predetermined thickness is formed on the upper portion of the cylinder body 3, and a horizontal installation surface 8 is formed at the lower end of the installation wall 3c. The upper end portion of the cylinder hole forming wall portion 3a is constituted by a part of the installation wall portion 3c, and the cylinder hole forming wall portion 3a is inserted into the through hole 9a of the base member 9 to which the clamping device 1 is attached, The cylinder body 3 is fixed to the base member 9 with four bolts inserted into the four bolt holes 10 in a state where 8 is in contact with the upper surface of the base member 9.

  Of the first and second cylinder holes 4a and 4b, the first and second clamping fluid pressure operating chambers 11a and 11b are provided on the rod side end wall 3b side with respect to the first and second piston portions 5a and 5b, respectively. The first and second unclamping fluid pressure actuation is formed on the opposite side of the rod-side end wall 3b with respect to the first and second piston portions 5a and 5b of the first and second cylinder holes 4a and 4b. Chambers 12a and 12b are respectively formed.

  The partition wall 7 has a large-diameter portion 7a of about 2/3 on the upper side and a small-diameter portion 7b of about ３ on the lower side, and the lower end of the outer peripheral portion of the large-diameter portion 7a is the cylinder hole forming wall portion 3a. The partition wall 7 is regulated so as not to move downward by being received by a stop ring 13 attached to the inner surface portion of the partition wall 7. The outer diameter of the lower half portion of the large diameter portion 7a is slightly larger than the outer diameter of the upper half portion of the large diameter portion 7a, and is restricted so that the partition wall 7 does not move upward.

  The piston rod 6 has a vertical axis and is integrally formed with the first piston portion 5a, and the upper half of the piston rod 6 passes through the rod hole 14 of the rod side end wall 3b and moves upward of the cylinder body 3. It extends. The base end portion of the clamp arm 15 in a horizontal posture is fixed to the upper end portion of the piston rod 6. That is, the upper end portion of the piston rod 6 is formed with a tapered portion 6a having a smaller diameter toward the upper side. The base end portion of the clamp arm 15 is externally fitted to the tapered portion 6a and screwed from the upper end of the clamp rod 6. A base end portion of the clamp arm 15 is fastened and fixed to the clamp rod 6 via a washer 16 a by a vertical fixing bolt 16. A seal member 17 and a dust seal 18 are mounted on the inner peripheral portion of the rod hole 14 of the rod side end wall 3b.

  The lower half portion of the piston rod 6 extends through the rod hole 19 (piston rod through hole) of the partition wall 7 into the second cylinder hole 4b, and the small diameter shaft portion 6b at the lower end portion of the piston rod 6 is the second piston. The second piston portion 5 b is connected to the piston rod 6 so as to move up and down integrally with the piston rod 6 by a stop ring 21 inserted through the rod hole 20 of the portion 5 b and attached to the lower end portion of the piston rod 6.

  A seal member 22 is attached to the outer periphery of the first piston portion 5a, a seal member 23 is attached to the outer periphery of the second piston portion 5b, and a seal is attached to the inner periphery of the rod hole 20 of the second piston portion 5b. A member 24 is mounted. A seal member 25 is attached to the outer peripheral portion in the vicinity of the upper end of the partition wall 7, and a seal member 26 is attached to the inner peripheral portion of the partition wall 7 in the vicinity of the upper end of the rod hole 19. The head side end wall 3d is prevented from coming off by a stop ring 27 attached to the cylinder hole forming wall 3a, and a seal member 28 is attached to the outer periphery of the head side end wall 3d.

  A clamping fluid pressure passage 32 capable of supplying fluid pressure from one common first fluid pressure port 31 to the first and second clamping fluid pressure working chambers 11 a and 11 b is formed in the wall portion of the cylinder body 3. ing. An unclamping fluid pressure passage 34 capable of supplying a fluid pressure from the second fluid pressure port 33 to the first unclamping fluid pressure working chamber 12 a is formed in the wall portion of the cylinder body 3. A fluid pressure passage 35 in the rod that communicates with the two unclamping fluid pressure working chambers 12a and 12b is formed. The upper end of the in-rod fluid pressure passage 35 communicates with the first unclamping fluid pressure working chamber 12a in the vicinity of the lower end of the first piston portion 5a.

  The first fluid pressure port 31 is formed so as to face the installation surface 8 of the installation wall 3c, the first fluid pressure passage 9b in the base member 9 is connected to the first fluid pressure port 31, and the first fluid pressure passage 9b is connected to a fluid pressure supply source (not shown). The second fluid pressure port 33 is formed so as to face the installation surface 8 of the installation wall 3c, a second fluid pressure passage (not shown) in the base member 9 is connected to the second fluid pressure port 33, and the second fluid pressure port 33 The fluid pressure passage is connected to a fluid pressure supply source (not shown).

  The clamping fluid pressure passage 32 is formed in the partition wall 7 so as to communicate with the fluid pressure passage 32a formed in the installation wall portion 3c and the cylinder hole forming wall portion 3a of the cylinder body 3, and the fluid pressure passage 32a. And a fluid pressure passage 32b. An annular groove 36 is formed in the inner peripheral portion of the partition wall mounting hole 4c in which the partition wall 7 is mounted and the outer peripheral portion of the partition wall 7 so as to communicate with the lower end portion of the fluid pressure passage 32b. The fluid pressure passage 32b in the partition wall 7 extends horizontally from the annular groove 36 and then extends downward, and communicates with the second clamping fluid pressure working chamber 11b.

  The unclamping fluid pressure passage 34 extends from the second fluid pressure port 33, passes through the interior of the installation wall 3 c, the rod side end wall 3 b, and the cylinder hole forming wall 3 a, and enters the first unclamping fluid pressure working chamber. It communicates with an annular groove 37 at the lower end of 12a.

  When the piston rod 6 retreats from the unclamped state to the clamped state, the piston rod 6 is turned 90 ° counterclockwise in plan view, and the piston rod 6 is extended from the clamped state to the unclamped state. A piston rod turning mechanism 40 that turns the piston rod 6 by 90 ° in a clockwise direction in a plan view is provided.

The piston rod turning mechanism 40 includes a plurality of (for example, three) steel balls 41 mounted on the inner peripheral wall portion of the rod hole 19 of the partition wall 7 and the piston rod 6 so that these steel balls 41 engage with each other. A plurality of (for example, three) engaging grooves 42 formed on the outer peripheral portion.
Each engagement groove 42 is formed by a spiral groove 42a having an opening angle of 90 ° with respect to the center of the piston rod 6 and a linear groove linearly extending upward from the upper end of the spiral groove 42a.

Next, the operation and effect of the pull type clamp device 1 described above will be described.
When switching from the unclamped state of FIG. 1 to the clamped state of FIG. 3, fluid pressure is supplied from the first fluid pressure port 31 to the first and second clamping fluid pressure working chambers 11 a and 11 b, When the fluid pressure is discharged from the clamping fluid pressure working chambers 12a and 12b, the first and second piston portions 5a and 5b receive pressure, and the piston rod 6 is clamped in the retracted direction to be in the clamped state of FIG.

  In the unclamped state, the clamp arm 15 faces rearward in FIG. 1, but when switching from the unclamped state to the clamped state, the piston rod 6 is moved by the piston rod turning mechanism 40 in the first half of the downward movement of the piston rod 6. It turns 90 ° counterclockwise, and in the second half of the downward movement, the piston rod 6 moves downward without turning to clamp the object to be clamped.

  When switching from the clamped state to the unclamped state, contrary to the above, fluid pressure is supplied to the first and second unclamping fluid pressure working chambers 12a and 12b, and the first and second clamping fluid pressure working chambers. The fluid pressure is discharged from 11a and 11b. At this time, in the first half of the upward movement of the piston rod 6, the piston rod 6 rises without turning, and in the second half of the upward movement, the piston rod 6 turns 90 ° clockwise.

  The clamping fluid pressure passage 32 capable of supplying fluid pressure from the common first fluid pressure port 31 to the first and second clamping fluid pressure working chambers 11a and 11b is formed in the wall portion of the cylinder body 3. The fluid pressure supply system for supplying fluid pressure to the fluid pressure working chambers 11a and 11b for the first and second clamps can be simplified, the clamp device 1 can be miniaturized, and the manufacturing cost can be reduced. Since the piston rod 6 can be clamp driven in the retreat direction by the fluid pressure in the first and second fluid pressure working chambers 11a and 11b, the driving force of the pull type clamp device 1 can be enhanced.

  Since it is not necessary to form a fluid pressure passage in the wall portion of the cylinder body 3 on the outer peripheral side of the second cylinder hole 4b, the second cylinder hole 4b is formed with a diameter larger than that of the first cylinder hole 4a. The pressure receiving area of the piston portion 5b can be increased to enhance the clamp driving force. The piston rod 6 can be turned by the piston rod turning mechanism 40 when the piston rod 6 is extended / retracted.

  In order to form the unclamping fluid pressure passage 34 capable of supplying fluid pressure to the first unclamping fluid pressure working chamber 12a in the wall portion of the cylinder body 3, fluid pressure is applied to the first unclamping fluid pressure working chamber 12a. The fluid pressure supply system to be supplied can be simplified, the clamp device 1 can be miniaturized, and the manufacturing cost can be reduced.

  Since the second unclamping fluid pressure working chamber 12b is formed in addition to the first unclamping fluid pressure working chamber 12a, the driving force for unclamping the piston rod 6 in the extending direction can be strengthened. Fluid pressure is supplied to the second unclamping fluid pressure working chamber 12b in order to form the in-rod fluid pressure passage 35 communicating with the first and second unclamping fluid pressure working chambers 12a, 12b in the piston rod 6. The fluid pressure supply system is simplified and compact.

A pull-type clamping device 1A according to the second embodiment will be described with reference to FIGS.
Since this pull type clamping device 1A is obtained by omitting some of the components of the pull type clamping device 1, the same components as those of the pull type clamping device 1 are denoted by the same reference numerals and description thereof is omitted. Only different configurations will be described.

  In the tandem fluid pressure cylinder 2A of this pull type clamp device 1A, there is no need to reinforce the unclamping driving force, so the head side end wall 3d, the stop ring 27, and the second unclamping fluid pressure working chamber. 12b is omitted. Therefore, the structure of the pull type clamp device 1A is somewhat simplified.

A pull-type clamping device 1B according to the third embodiment will be described with reference to FIGS.
Since this pull type clamp device 1B is obtained by changing only a part of the configuration of the pull type clamp device 1, the same components as those of the pull type clamp device 1 are denoted by the same reference numerals and description thereof is omitted. Only different configurations will be described.

  In the tandem fluid pressure cylinder 2B of the pull type clamp device 1B, the partition wall 7B includes a large diameter portion 7a, a lower end side small diameter portion 7b extending downward from the lower end of the large diameter portion 7a, and a large diameter portion 7a. And an upper end side small diameter portion 7c extending upward from the upper end. The turning mechanism 40 is formed in the upper end side small diameter portion 7 c and the piston rod 6.

  A cylinder portion 29 that extends a predetermined length from the second piston portion 5b toward the partition wall 7B and is fluidly slidably inserted into the large diameter portion 7a and the lower end side small diameter portion 7b of the partition wall 7B. A cylindrical portion 29 that is externally fitted and fixed to the second piston portion 5b is integrally formed. The lower portion of the piston rod 6 is inserted into a rod hole 29 a formed in the cylindrical portion 29, and the cylindrical portion 29 is slidably inserted into an insertion hole 7 h formed in the partition wall 7.

  A rod external fluid pressure passage 30 that communicates the first and second unclamping fluid pressure working chambers 12 a and 12 b is formed on the outer peripheral side of the piston rod 6. The rod outside fluid pressure passage 30 is constituted by a lower end portion of the engagement groove 42 and a linear groove 30 a formed linearly on the inner peripheral portion of the rod hole 29 a of the cylindrical portion 29. The upper end portion of the linear groove 30a is formed wide in the circumferential direction so as to always communicate with the lower end portion of any of the engagement grooves 42 even when the piston rod 6 turns. A seal member 38 is attached to the inner peripheral portion of the insertion hole 7h in the vicinity of the lower end of the insertion hole 7h.

  In this pull type clamp device 1B, since there is no seal member between the piston rod 6 and the partition wall 7B, the frictional resistance acting on the piston rod 6 when the piston rod 6 turns is reduced, so that the turning performance is improved. be able to.

A pull-type clamping device 1C according to the fourth embodiment will be described with reference to FIGS.
Since this pull type clamping device 1C is obtained by changing only a part of the configuration of the pull type clamping device 1, the same components as those of the pull type clamping device 1 are denoted by the same reference numerals and description thereof is omitted. Only different configurations will be described.

The tandem fluid pressure cylinder 2C of the pull clamp device 1C is provided with a clamp failure detection means 50 including a fluid pressure short-circuit passage 51, an on-off valve mechanism 52, a pressure sensor 53, and a control unit 57 as follows. .
A fluid pressure short-circuit passage 51 is formed in the partition wall 7C to connect the clamping fluid pressure passage 32 and the annular groove 36 to the first unclamping fluid pressure working chamber 12a. The fluid pressure short-circuit passage 51 includes a first piston. An opening / closing valve mechanism 52 is provided that opens only when the part 5a moves to the clamp side by a full stroke.

  The on-off valve mechanism 52 has a vertical axis, and includes a valve body accommodation hole 54, a valve body 55, and a compression spring 56. The valve body accommodation hole 54 has a large diameter hole 54a and a small diameter hole 54b extending from the upper end of the large diameter hole 54a to the first unclamping fluid pressure working chamber 12a.

  The valve body 55 includes a large-diameter portion 55a and a medium-diameter portion 55b accommodated in the large-diameter hole 54a, and a small-diameter that extends from the upper end of the medium-diameter portion 55b into the small-diameter hole 54b and faces the first piston portion 5a. A small-diameter portion 55c having an upper end projecting into the first unclamping fluid pressure working chamber 12a. A compression spring 56 for urging the valve body 55 upward is attached to the lower portion of the large diameter hole 54a.

  When the upper end outer peripheral portion of the medium diameter portion 55b comes into contact with the lower end of the outer peripheral side wall portion of the small diameter hole 54b, the valve is closed (see FIG. 9), and only when the first piston portion 5a moves to the clamp side by a full stroke. Since 1 piston part 5a pushes the valve body 55 below, it will be in a valve opening state (refer FIG. 11).

  A pressure sensor 53 (or pressure switch) capable of detecting the fluid pressure in the first fluid pressure passage 9 b in the base member 9 is provided, and a detection signal of the pressure sensor 53 is output to the control unit 57.

  When the clamp device 1C is driven to be clamped, if the object to be clamped is clamped normally, the first piston portion 5a does not move to the clamp side in the full stroke, so as shown in FIGS. The piston part 5a does not push the valve body 55, and the on-off valve mechanism 52 maintains the valve closed state. Therefore, the fluid pressure in the first fluid pressure passage 9b does not drop abnormally, and the control unit 57 can detect normal clamping from the detection signal of the pressure sensor 53.

  On the other hand, when the clamping object 1C is driven when the clamping object does not exist or the thickness of the clamping object is too small, the first piston portion 5a moves full stalk toward the clamping side. As shown in FIGS. 10 and 11, the on-off valve mechanism 52 is opened, and the fluid pressure in the first fluid pressure passage 9b drops abnormally. Therefore, the control unit 57 can detect that a clamping failure has occurred from the detection signal of the pressure sensor 53.

Next, an example in which the above embodiment is partially changed will be described.
1) The clamping failure detection means 50 according to the fourth embodiment can be applied to the pull-type clamping devices 1A and 1B according to the second and third embodiments.

  2) The first and second fluid pressure ports 31 and 33 do not have to be formed so as to face the installation surface 8 of the installation wall 3c, and may be formed so as to face the side surface of the installation wall 3c.

  3) Although the tandem fluid pressure cylinder in the above embodiment has been described as an example having two first and second cylinder holes and first and second piston portions, three or more cylinders formed in series A tandem fluid pressure cylinder having a hole and three or more piston portions is also applicable to the pull type clamping device of the present application.

  4) In addition, those skilled in the art can implement the present invention by adding various modifications to the above-described embodiments, and the present invention includes such modifications.

1, 1A to 1C Pull type clamping device 2, 2A to 2C Tandem type fluid pressure cylinder 3 Cylinder body 3a Cylinder hole forming wall 3b Rod side end wall 3d Head side end wall 4a, 4b First and second cylinder holes 5a, 5b First and second piston portions 6 Piston rods 7, 7B, 7C Partition walls 11a, 11b First and second clamping fluid pressure working chambers 12a, 12b First and second unclamping fluid pressure working chambers 19 Rod penetration Hole (rod hole)
29 Cylinder portion 30 Rod external fluid pressure passage 31 First fluid pressure port 32 Clamping fluid pressure passage 34 Unclamping fluid pressure passage 35 In-rod fluid pressure passage 40 Turning mechanism 41 Steel ball 42a Spiral groove 51 Fluid pressure short-circuit passage 52 Opening and closing Valve mechanism

Claims (5)

In the pull type clamp device that is configured to clamp the piston rod in the retracted direction by the tandem fluid pressure cylinder,
The tandem fluid pressure cylinder includes a cylinder body, first and second cylinder holes formed in series in the cylinder body so as to be aligned in the retreat direction, and the first and second cylinder holes. Each of the first and second piston parts movably mounted on each of the first and second piston parts, and a common piston rod fixed to the first and second piston parts and extending from the first piston part side to the outside of the cylinder body,
The cylinder body includes a cylinder hole forming wall portion, a rod side end wall integral with the cylinder hole forming wall portion, and a partition wall through which the piston rod penetrates while partitioning between the first and second cylinder holes,
Of the first and second cylinder holes, first and second clamping fluid pressure working chambers are formed on the rod side end wall side with respect to the first and second piston portions, respectively.
A clamping fluid pressure passage capable of supplying fluid pressure from one common fluid pressure port to the first and second clamping fluid pressure working chambers is formed in the wall of the cylinder body .
A first unclamping fluid pressure working chamber is formed on the partition wall side with respect to the first piston portion of the first cylinder hole, and the first unclamping fluid pressure working chamber is formed in the wall portion of the cylinder body. An unclamping fluid pressure passage capable of supplying fluid pressure is formed,
The cylinder body has a head side end wall that closes an end of the second cylinder hole,
A second unclamping fluid pressure working chamber is formed on the head side end wall side with respect to the second piston portion of the second cylinder hole,
A pull-type clamping device , wherein a fluid pressure passage in the rod communicating with the first and second unclamping fluid pressure working chambers is formed in the piston rod .   2. The pull-type clamp device according to claim 1, wherein an inner diameter of the second cylinder hole is formed larger than an inner diameter of the first cylinder hole and an outer diameter of the partition wall. 3. A pull-type clamping device according to claim 1, further comprising a piston rod turning mechanism having a plurality of steel balls and a plurality of spiral grooves into which the plurality of steel balls respectively engage . The plurality of steel balls are attached to an inner peripheral wall portion of a piston rod through hole of the partition wall,
The pull-type clamping device according to claim 3 , wherein the plurality of spiral grooves are formed on an outer peripheral portion of the piston rod . A fluid pressure short-circuit passage is formed in the partition wall to communicate the clamping fluid pressure passage with the first unclamping fluid pressure working chamber,
The pull-type clamp device according to claim 1 , wherein an opening / closing valve mechanism is provided in the fluid pressure short-circuiting passage so that the valve is opened only when the first piston part is moved by a full stroke toward the clamp side .