JP2022041872A - Magnet chuck - Google Patents

Abstract

SOLUTION: A magnet chuck 10 includes: a cylinder tube 12 having a workpiece suction surface 12c onto which a workpiece W is suctioned; a piston assembly 14 including a permanent magnet 42, being movable in an internal space 25 of the cylinder tube, and separating the internal space of the cylinder tube into a first pressure chamber 112 and a second pressure chamber 114; a first supply/discharge port 26 formed in the cylinder tube and communicating with the first pressure chamber; a second supply/discharge port 76 formed in the cylinder tube and communicating with the second pressure chamber; and a communication passage 71 providing communication between the first pressure chamber and the second pressure chamber.SELECTED DRAWING: Figure 3

Description

The present invention relates to a magnet chuck.

A magnet chuck is known in which a permanent magnet is connected to a piston inside a cylinder and the permanent magnet is displaced together with the piston (see Patent Document 1). In such a magnet chuck, the permanent magnet approaches the work following the displacement of the piston that has received the fluid pressure. As the permanent magnet approaches the work, the work is attracted and held. Further, when the piston is displaced in the direction away from the work, the work is released.

Jikkai Sho 51-102174

When attracting and holding a high-temperature workpiece, it is conceivable that the member provided in the magnet chuck will be damaged. Even when the high-temperature work is attracted and held, it is preferable to suppress damage to the member provided on the magnet chuck.

An object of the present invention is to provide a magnet chuck having good heat resistance.

The magnet chuck according to one aspect of the present invention includes a cylinder tube having a work suction surface on which the work is attracted, and a permanent magnet, and is movable in the internal space of the cylinder tube, so that the internal space of the cylinder tube can be moved. A piston assembly that separates the first pressure chamber and the second pressure chamber, a first supply / discharge port formed in the cylinder tube and communicating with the first pressure chamber, and a second pressure formed in the cylinder tube. It is provided with a second supply / discharge port that communicates with the chamber, and a communication passage that communicates the first pressure chamber and the second pressure chamber.

According to the present invention, it is possible to provide a magnet chuck having good heat resistance.

It is a front view which shows the magnet chuck by 1st Embodiment. It is sectional drawing which shows the magnet chuck by 1st Embodiment. It is sectional drawing which shows the magnet chuck by 1st Embodiment. It is an exploded perspective view which shows the magnet chuck by 1st Embodiment. It is sectional drawing which shows the magnet chuck by 2nd Embodiment. It is sectional drawing which shows the magnet chuck by 2nd Embodiment. It is sectional drawing which shows the magnet chuck by 3rd Embodiment. It is sectional drawing which shows the magnet chuck by 3rd Embodiment. It is a back view which shows the magnet chuck by 4th Embodiment. It is sectional drawing which shows the magnet chuck by 4th Embodiment. It is sectional drawing which shows the magnet chuck by 4th Embodiment. It is sectional drawing which shows a part of the magnet chuck by the modification of 4th Embodiment. It is a block diagram which shows the magnet chuck by the modification of 4th Embodiment.

A suitable embodiment of the magnet chuck according to the present invention will be described in detail below with reference to the accompanying drawings.

[First Embodiment]
The magnet chuck according to the first embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a front view showing a magnet chuck according to the present embodiment. 2 and 3 are cross-sectional views showing a magnet chuck according to the present embodiment. The state where the piston assembly 14 is located at the top dead center is shown in FIG. The state in which the piston assembly 14 is located at the bottom dead center is shown in FIG. Further, FIG. 3 shows a state in which the work W is attracted to the magnet chuck 10. FIG. 4 is an exploded perspective view showing a magnet chuck according to the present embodiment. In the specification of the present application, the upper surface of the paper surface in FIG. 1 of the magnet chuck 10 is referred to as an upper surface, and the lower surface of the magnet chuck 10 in FIG. 1 is referred to as a lower surface. The work W is attracted to the lower surface side of the magnet chuck 10.

As shown in FIGS. 2 and 3, the magnet chuck 10 according to the present embodiment includes a cylinder tube 12, a piston assembly 14, a bottom cover 18, and a latch yoke 20. The magnet chuck 10 is attached to, for example, the tip arm of a robot (not shown).

A cylinder hole 24 is formed in the cylinder tube 12. The cylinder hole 24 penetrates the cylinder tube 12. The shape of the cross section of the cylinder hole 24 is, for example, a circle. That is, the shape of the cross section of the cylinder hole 24 in the direction perpendicular to the central axis C of the cylinder tube 12 is, for example, a circle. The central axis of the cylinder hole 24 coincides with the central axis C of the cylinder tube 12. As the material of the cylinder tube 12, for example, a paramagnetic metal such as an aluminum alloy is used, but the material is not limited thereto.

As shown in FIG. 1, the cylinder tube 12 includes a first end portion 12d and a second end portion 12e. The first end 12d and the second end 12e are located opposite to each other. The first end portion 12d includes a work suction surface 12c to which the work W is sucked. As shown in FIGS. 2 and 3, a fitting portion 22 that fits with the housing 86 described later is formed at the first end portion 12d of the cylinder tube 12. The outer shape of the cross section of the cylinder tube 12 excluding the fitting portion 22 is, for example, rectangular. The outer shape of the cross section of the fitting portion 22 of the cylinder tube 12 is, for example, circular.

At the tip of the fitting portion 22 of the cylinder tube 12, a step portion 23 to which the second sealing material 96 described later is mounted is formed. Further, on the upper side of the cylinder hole 24, a step portion 32 formed on the latch yoke 20 to which the flange 20a described later is engaged is formed.

The piston assembly 14 includes a seal holder 38, a core yoke 40, a permanent magnet 42, a cover yoke 44, and a ring plate 45.

The seal holder 38 is formed in a disk shape. As the material of the seal holder 38, for example, a paramagnetic metal such as an aluminum alloy is used, but the material is not limited thereto. A concave groove 39 is formed on the outer periphery of the seal holder 38. The concave groove 39 opens toward the outside in the circumferential direction of the seal holder 38. A piston seal 46 is attached to the concave groove 39. As the material of the piston seal 46, for example, fluororubber or the like is used, but the material is not limited thereto. The piston seal 46 is in sliding contact with the wall surface of the cylinder hole 24. A through hole 48 is formed in the center of the seal holder 38. The through hole 48 is formed with an inward flange 50 projecting toward the center of the through hole 48. An annular recess 51 is formed on the upper surface of the seal holder 38. The annular recess 51 opens toward the upper surface side of the magnet chuck 10. The portion existing between the through hole 48 and the annular recess 51 is the flange 41. The flange 41 projects toward the upper surface side of the magnet chuck 10.

The core yoke 40 is formed in a columnar shape as a whole. As the material of the core yoke 40, for example, steel which is a ferromagnet is used, but the material is not limited thereto. A cylindrical protrusion 52 is formed in the center of the upper end of the core yoke 40. The tubular protruding portion 52 projects toward the upper surface side of the magnet chuck 10. The core yoke 40 is formed with a bottomed screw hole 54. The screw hole 54 is open at the tip of the tubular protrusion 52. A recess 56 is formed on the lower side of the core yoke 40. The recess 56 is open toward the lower surface side of the magnet chuck 10. The shape of the cross section of the recess 56 is, for example, a circle.

A tubular protrusion 52 of the core yoke 40 is inserted into the through hole 48 formed in the seal holder 38. The tubular protrusion 52 is inserted into the lower portion of the through hole 48. The tubular protrusion 52 is fitted in the through hole 48. The tubular protrusion 52 is in contact with the inward flange 50 of the seal holder 38. A fixing screw 60 is inserted into the through hole 48. The fixing screw 60 is inserted from the upper side of the through hole 48. The fixing screw 60 is further inserted into the screw hole 54 formed in the core yoke 40. The fixing screw 60 is screwed into the screw hole 54. In this way, the seal holder 38 and the core yoke 40 are integrally connected.

A first sealing material 62 is attached to the base of the tubular protrusion 52. The first sealing material 62 seals between the seal holder 38 and the core yoke 40. As the material of the first sealing material 62, for example, fluororubber or the like is used, but the material is not limited thereto.

The permanent magnet 42 is formed, for example, in a cylindrical shape. The permanent magnet 42 is located on the outer circumference of the core yoke 40. As the permanent magnet 42, for example, a samarium-cobalt magnet is used, but the permanent magnet 42 is not limited thereto. The permanent magnet 42 is surrounded by a seal holder 38, a core yoke 40, a cover yoke 44, and a ring plate 45. The permanent magnet 42 is magnetized in the radial direction, for example. The inner peripheral side of the permanent magnet 42 is, for example, an N pole, and the outer peripheral side of the permanent magnet 42 is, for example, an S pole. The inner peripheral side of the permanent magnet 42 may be the S pole, and the outer peripheral side of the permanent magnet 42 may be the N pole. The permanent magnet 42 is divided in the circumferential direction, for example. That is, a cylindrical permanent magnet 42 is configured by combining a plurality of fan-shaped magnet pieces (not shown). The permanent magnet 42 may be configured by a single member. The permanent magnet 42 is not limited to a cylindrical shape. For example, the permanent magnet 42 may be formed in a square cylinder shape. That is, a square tubular permanent magnet 42 may be configured by combining a plurality of flat plate-shaped magnet pieces.

The cover yoke 44 is formed in a tubular shape. The cover yoke 44 is located on the outer periphery of the permanent magnet 42. As the material of the cover yoke 44, for example, steel which is a ferromagnet is used, but the material is not limited thereto. The outer circumference of the cover yoke 44 has a large diameter on the upper side and a small diameter on the lower side. That is, the cover yoke 44 includes a large diameter portion 64 and a small diameter portion 66. A step portion 65 exists between the large diameter portion 64 and the small diameter portion 66. Two annular grooves 68a and 68b are formed in the large diameter portion 64. The annular grooves 68a and 68b are open outward in the radial direction of the cover yoke 44. The annular grooves 68a and 68b are separated from each other in the direction along the central axis C of the cylinder tube 12. Wear rings 70a and 70b are attached to the annular grooves 68a and 68b, respectively. The piston assembly 14 is guided and supported in the cylinder hole 24 via the wear rings 70a and 70b. As the material of the wear rings 70a and 70b, for example, polytetrafluoroethylene (PTFE: PolyTetraFluoroEthylene) or the like is used. The materials of the wear rings 70a and 70b are not limited to such materials.

The bottom cover 18 includes a bottom yoke 80, an outer yoke 82, and a housing 86.

As the material of the bottom yoke 80, for example, steel which is a ferromagnet is used, but the material is not limited thereto. The shape of the bottom yoke 80 is, for example, a columnar shape. When the piston assembly 14 is lowered, the bottom yoke 80 enters the recess 56 of the core yoke 40 (see FIG. 3). A lower flange 80a is formed at the lower portion of the bottom yoke 80. The lower flange 80a projects radially outward of the bottom yoke 80.

An outer yoke 82 is provided on the outside of the bottom yoke 80. As the material of the outer yoke 82, for example, steel which is a ferromagnet is used, but the material is not limited thereto. The outer yoke 82 is formed, for example, in a cylindrical shape. An upper flange 82a is formed on the upper side of the outer yoke 82. The upper flange 82a projects outward in the radial direction of the outer yoke 82. An outer peripheral recess 82b is formed on the outer peripheral surface on the lower side of the outer yoke 82. The outer peripheral recess 82b is recessed inward in the radial direction of the outer yoke 82. A stepped portion 82c is formed on the inner peripheral surface on the lower side of the outer yoke 82.

An annular connecting plate 84 is provided between the lower flange 80a of the bottom yoke 80 and the stepped portion 82c of the outer yoke 82. The outer yoke 82 is fixed to the bottom yoke 80 by the connecting plate 84. As the material of the connecting plate 84, for example, a paramagnetic metal such as an aluminum alloy is used, but the material is not limited thereto.

The housing 86 is formed, for example, in a cylindrical shape. As the material of the housing 86, for example, a paramagnetic metal such as an aluminum alloy is used, but the material is not limited thereto. The housing 86 is formed with a through hole 88 that penetrates in the vertical direction. The cross section of the through hole 88 is circular. A lower flange 90 is formed on the lower side of the through hole 88. The lower flange 90 projects radially inward of the through hole 88. The fitting portion 22 of the cylinder tube 12 is fitted into the through hole 88 of the housing 86.

As shown in FIG. 4, four tie rods 94 are inserted into the insertion holes 35 formed in the housing 86. The tip of each tie rod 94 is screwed into a screw hole (not shown) formed in the cylinder tube 12. In this way, the cylinder tube 12 and the housing 86 are connected and fixed to each other. The upper flange 82a of the outer yoke 82 is sandwiched between the end surface of the fitting portion 22 of the cylinder tube 12 and the lower flange 90 of the housing 86. In this way, the outer yoke 82 is connected and fixed to the cylinder tube 12 and the like.

As described above, a step portion 23 is formed at the tip of the fitting portion 22 of the cylinder tube 12. A second sealing material 96 is attached to the gap between the step portion 23 and the upper surface of the outer yoke 82. The second sealing material 96 seals between the cylinder tube 12 and the outer yoke 82. As the material of the second sealing material 96, for example, fluororubber or the like is used, but the material is not limited thereto.

A damper (lower damper 98) is mounted between the lower end of the cylinder tube 12 and the upper surface of the outer yoke 82. The lower damper 98 is formed in an annular shape. As the material of the lower damper 98, for example, fluororubber or the like is used, but the material is not limited thereto. The upper surface of the lower damper 98 faces the annular recess 30 formed in the cylinder tube 12. When the piston assembly 14 descends to the bottom dead center, the step portion 65 of the cover yoke 44 abuts on the lower damper 98, as shown in FIG. The lower damper 98 serves to mitigate the impact generated when the piston assembly 14 is moved within the interior space 25. That is, the lower damper 98 plays a role of cushioning the impact when the piston assembly 14 descends to the bottom dead center. As shown in FIG. 4, a plurality of grooves 98a (plurality of concave grooves) are formed on the upper surface of the lower damper 98 from the inner peripheral end of the lower damper 98 to the outer peripheral end of the lower damper 98. The plurality of grooves 98a are formed at equal intervals, for example, in the circumferential direction of the lower damper 98. The groove 98a plays a role of communicating the first fluid supply / discharge hole 28, which will be described later, with the cylinder hole 24. That is, the groove 98a plays a role of communicating the first supply / discharge port 26, which will be described later, with the first pressure chamber 112, which will be described later. Even when the piston assembly 14 is located at the bottom dead center, the first fluid supply / discharge hole 28 communicates with the cylinder hole 24 via the groove 98a. The groove 98a also plays a role of communicating the second communication hole 74b, which will be described later, with the cylinder hole 24. That is, the groove 98a also plays a role of communicating the first communication passage 71A, which will be described later, to the first pressure chamber 112.

The work W is attracted to the lower surface of the magnet chuck 10. Examples of the work W include, but are not limited to, an iron plate and the like.

The latch yoke 20 is formed in a disk shape. As the material of the latch yoke 20, for example, steel which is a ferromagnet is used, but the material is not limited thereto. A flange 20a is formed on the upper side of the latch yoke 20. The flange 20a projects outward in the radial direction of the latch yoke 20. The flange 20a is engaged with a step portion 32 formed on the upper side of the cylinder hole 24. A recess 102 is formed in the center of the latch yoke 20. The recess 102 opens toward the lower surface side of the magnet chuck 10. The cross section of the recess 102 is, for example, circular. The recess 102 includes a small diameter portion 102a and a large diameter portion 102b. The small diameter portion 102a is located on the upper side of the recess 102. The large diameter portion 102b is located on the lower side of the recess 102. When the piston assembly 14 is raised, the head 60a of the fixing screw 60 is received in the small diameter portion 102a (see FIG. 2). An upper damper 104 is attached to the large diameter portion 102b. The upper damper 104 is formed in an annular shape. When the piston assembly 14 is raised, the flange 41 of the seal holder 38 comes into contact with the upper damper 104, as shown in FIG. The upper damper 104 serves to cushion the impact of the piston assembly 14 as it rises. As the material of the upper damper 104, for example, fluororubber or the like is used, but the material is not limited thereto. An annular protrusion 106 is formed at the lower end of the large diameter portion 102b. The inner diameter of the annular protrusion 106 is tapered downward. The annular protrusion 106 enters the annular recess 51 formed in the seal holder 38 when the piston assembly 14 is raised. A concave groove 21 is formed on the outer periphery of the latch yoke 20. The concave groove 21 is open to the outside of the latch yoke 20 in the radial direction. A latch yoke seal 27 is attached to the concave groove 21. As the material of the latch yoke seal 27, for example, fluororubber or the like is used, but the material is not limited thereto. A small diameter portion 20b is formed on the lower side of the latch yoke 20. A gap 114a exists between the outer peripheral surface of the small diameter portion 20b of the latch yoke 20 and the wall surface of the cylinder hole 24. The gap 114a is a part of the second pressure chamber 114 described later.

A concave groove 12b is formed on the upper side of the cylinder tube 12. The concave groove 12b opens toward the central axis C of the cylinder tube 12. A snap ring 16 is fitted in the concave groove 12b. The snap ring 16 is a ring-shaped retaining ring for preventing the latch yoke 20 from coming off in the axial direction of the cylinder tube 12. The axial direction of the cylinder tube 12 is a direction along the central axis C. As the material of the snap ring 16, for example, steel for a spring is used, but the material is not limited thereto.

The internal space 25 of the cylinder tube 12 is separated into a first pressure chamber 112 and a second pressure chamber 114 by a piston assembly 14. The first pressure chamber 112 is a pressure chamber located below the piston seal 46 of the seal holder 38. The second pressure chamber 114 is a pressure chamber located above the piston seal 46 of the seal holder 38. The first pressure chamber 112 is located between the second pressure chamber 114 and the work suction surface 12c.

The cylinder tube 12 is formed with a first supply / discharge port 26 for supplying / discharging fluid to / from the first pressure chamber 112. The cylinder tube 12 includes a first side portion 12f and a second side portion 12g. The first side portion 12f and the second side portion 12g are located opposite to each other with respect to the central axis C of the cylinder tube 12. The first supply / discharge port 26 is provided on the first side portion 12f of the cylinder tube 12. The cylinder tube 12 has a first side surface 13A and a second side surface 13B. The first side surface 13A and the second side surface 13B are located opposite to each other. The first supply / discharge port 26 is open on the first side surface 13A of the cylinder tube 12. As the fluid, for example, a gas such as air is used, but the fluid is not limited to this. A liquid such as water or oil may be used as the fluid. The temperature of the fluid is, for example, room temperature (about 25 ° C.), but is not limited thereto. However, in order to sufficiently cool the inside of the magnet chuck 10, it is preferable that the temperature of the fluid is sufficiently lower than the temperature of the work W.

A first fluid supply / discharge hole 28 is formed inside the wall 12a of the cylinder tube 12. A first supply / discharge port 26 is connected to the upper end of the first fluid supply / discharge hole 28. The first fluid supply / discharge hole 28 extends inside the wall 12a of the cylinder tube 12 along the axial direction of the cylinder tube 12. An annular recess 30 that opens toward the lower surface side of the magnet chuck 10 is formed on the inner peripheral side of the fitting portion 22. The lower end of the first fluid supply / discharge hole 28 reaches the annular recess 30. The first supply / discharge port 26 communicates with the first pressure chamber 112 via the first fluid supply / discharge hole 28. The first fluid supply / discharge hole 28 has an opening 81b communicating with the first pressure chamber 112. The opening 81b communicating with the first pressure chamber 112 is provided in the first side portion 12f of the cylinder tube 12.

The cylinder tube 12 is provided with a second supply / discharge port 76 for supplying / discharging fluid to / from the second pressure chamber 114. The second supply / discharge port 76 is provided on the first side portion 12f of the cylinder tube 12 in the same manner as the first supply / discharge port 26. The second supply / discharge port 76 is open on the first side surface 13A of the cylinder tube 12. The second supply / discharge port 76 is located above the first supply / discharge port 26.

A second fluid supply / discharge hole 110 is formed inside the wall 12a of the cylinder tube 12. One end of the second fluid supply / discharge hole 110 is connected to the second supply / discharge port 76. The second fluid supply / discharge hole 110 extends inside the wall 12a of the cylinder tube 12 toward the cylinder hole 24. The other end of the second fluid supply / discharge hole 110 communicates with a gap 114a formed between the outer peripheral surface of the small diameter portion 20b of the latch yoke 20 and the wall surface of the cylinder hole 24. As described above, the gap 114a is a part of the second pressure chamber 114. The second supply / discharge port 76 communicates with the second pressure chamber 114 via the second fluid supply / discharge hole 110. The second fluid supply / discharge hole 110 has an opening 81a communicating with the second pressure chamber 114. The opening 81a communicating with the second pressure chamber 114 is provided in the first side portion 12f of the cylinder tube 12.

The cylinder tube 12 is formed with a communication passage 71 for communicating the first pressure chamber 112 and the second pressure chamber 114. The communication passage 71 includes the first communication passage 71A. The first communication passage 71A is formed inside the wall 12a of the cylinder tube 12. The first communication passage 71A is formed separately from the internal space 25 of the cylinder tube 12. The first continuous passage 71A is provided on the second side portion 12g of the cylinder tube 12. As described above, the first side portion 12f and the second side portion 12g are located opposite to each other with respect to the central axis C of the cylinder tube 12. The first supply / discharge port 26 and the second supply / discharge port 76 are provided on the first side portion 12f of the cylinder tube 12, and the first communication passage 71A is provided on the second side portion 12g of the cylinder tube 12. There is. The first supply / discharge port 26 and the second supply / discharge port 76 are arranged on the first side portion 12f of the cylinder tube 12, and the communication passage 71 is arranged on the second side portion 12g of the cylinder tube 12 as follows. For some reason. That is, this is to suppress the retention of the fluid in the first pressure chamber 112 and the second pressure chamber 114, and to effectively cool each part of the magnet chuck 10 by the fluid.

The first continuous passage 71A is provided with a flow rate adjusting valve 72 for adjusting the flow rate of the fluid flowing through the first continuous passage 71A, and more specifically, a needle valve. As described above, the second end portion 12e of the cylinder tube 12 is located opposite to the first end portion 12d including the work suction surface 12c. The flow rate adjusting valve 72 is provided at the second end portion 12e. The flow rate adjusting valve 72 is mounted in a recess 73 formed in the cylinder tube 12. The recess 73 opens outward in the radial direction of the cylinder tube 12. The recess 73 is open on the second side surface 13B of the cylinder tube 12. The depth direction of the recess 73 is the radial direction of the cylinder tube 12. The cross section of the recess 73 in the axial direction of the cylinder tube 12 is, for example, circular. The recess 73 is formed with a stepped portion 73a on which the sealing material 75, which will be described later, is mounted. A sealing material 75 is mounted in the gap between the step portion 73a and the flow rate adjusting valve 72. The sealing material 75 seals between the cylinder tube 12 and the flow rate adjusting valve 72. As the material of the sealing material 75, for example, fluororubber or the like is used, but the material is not limited thereto.

The first communication passage 71A includes a first communication hole 74a and a second communication hole 74b. One end of the first communication hole 74a communicates with a gap 114a formed between the outer peripheral surface of the small diameter portion 20b of the latch yoke 20 and the wall surface of the cylinder hole 24. The first communication hole 74a, that is, the communication hole has an opening 79a that communicates with the second pressure chamber 114. The opening 79a communicating with the second pressure chamber 114 is provided in the second side portion 12g of the cylinder tube 12. The other end of the first communication hole 74a is open at the bottom surface of the recess 73. The central axis of the first communication hole 74a and the central axis of the flow rate regulating valve 72 coincide with each other. The upper end of the second communication hole 74b is open on the side surface of the recess 73. The second communication hole 74b extends inside the wall 12a of the cylinder tube 12 toward the lower side of the cylinder tube 12. The lower end of the second communication hole 74b reaches the annular recess 30 formed in the cylinder tube 12. The first communication passage 71A communicates with the first pressure chamber 112 via a groove 98a formed in the lower damper 98. That is, the second communication hole 74b has an opening 79b that communicates with the first pressure chamber 112. The opening 79b communicating with the first pressure chamber 112 is provided in the second side portion 12g of the cylinder tube 12.

The flow rate adjusting valve 72 is provided with a body portion 72a and a core rod 72b. The body portion 72a is formed in a cylindrical shape as a whole. The core rod 72b is formed in a columnar shape as a whole. The core rod 72b is surrounded by the body portion 72a. The core rod 72b is provided with a large diameter portion 72b1 and a small diameter portion 72b2. The small diameter portion 72b2 is located at the tip of the core rod 72b. The small diameter portion 72b2 of the core rod 72b, that is, the tip of the core rod 72b is inserted into the first communication hole 74a. When the core rod 72b is rotated, the core rod 72b is displaced in the longitudinal direction of the core rod 72b. When the core rod 72b is displaced in the longitudinal direction of the core rod 72b, the size of the gap between the first series passage 71A and the core rod 72b changes, and the flow rate of the fluid in the first series passage 71A is adjusted. A gap between the first communication passage 71A and the core rod 72b so as to be able to generate a sufficient differential pressure between the first pressure chamber 112 and the second pressure chamber 114 when driving the piston assembly 14. The size is set small enough. An annular groove 72b3 is formed in the core rod 72b. The annular groove 72b3 opens outward in the radial direction of the core rod 72b. A sealing material 77 is attached to the annular groove 72b3. The sealing material 77 seals between the body portion 72a and the core rod 72b. As the material of the sealing material 77, for example, fluororubber or the like is used, but the material is not limited thereto.

The first supply / discharge port 26 and the first communication passage 71A communicate with each other via the first pressure chamber 112. Even when the piston assembly 14 is located at the bottom dead center, as shown in FIG. 3, the first supply / discharge port 26 and the first communication passage 71A communicate with each other via the first pressure chamber 112. Is maintained.

The second supply / discharge port 76 and the first communication passage 71A communicate with each other via the second pressure chamber 114. Even when the piston assembly 14 is located at the top dead center, as shown in FIG. 2, the second supply / discharge port 76 and the first communication passage 71A communicate with each other via the second pressure chamber 114. Is maintained.

In this way, the magnet chuck 10 according to the present embodiment is configured.

Next, the operation of the magnet chuck 10 according to the present embodiment will be described with reference to FIGS. 2 and 3. The state shown in FIG. 2, that is, the state in which the piston assembly 14 is located at the top dead center (rising end) is defined as the initial state.

In the state where the piston assembly 14 is located at the top dead center, the piston assembly 14 including the permanent magnet 42 is attracted to the latch yoke 20 by a predetermined magnetic attraction force.

In the stage before the magnet chuck 10 is put into use, for example, during transportation, the piston assembly 14 is held at the top dead center position by the action of the latch yoke 20 even if no fluid is supplied to the magnet chuck 10. Ru. As a result, an unexpected situation in which the magnet chuck 10 attracts the surrounding iron material or the like is avoided, and safety is achieved.

Next, while maintaining the magnet chuck 10 in the initial state, for example, a robot (not shown) is driven to bring the magnet chuck 10 into contact with the work W. More specifically, the lower surface side of the magnet chuck 10 is brought into contact with the work W.

Next, by operating a switching valve (not shown), the supply of the fluid into the second pressure chamber 114 is started, and the discharge of the fluid from the first pressure chamber 112 is started. The supply of the fluid into the second pressure chamber 114 is performed through the second supply / discharge port 76. The discharge of the fluid from the first pressure chamber 112 is performed through the first supply / discharge port 26.

When the supply of the fluid into the second pressure chamber 114 is started and the discharge of the fluid from the first pressure chamber 112 is started, a differential pressure is generated between the first pressure chamber 112 and the second pressure chamber 114. Therefore, a force for driving the piston assembly 14 downward acts on the piston assembly 14 according to the differential pressure between the first pressure chamber 112 and the second pressure chamber 114. The piston assembly 14 is held at top dead center when the force for driving the piston assembly 14 downward does not exceed the magnetic attraction force acting between the latch yoke 20 and the piston assembly 14. As described above, since the size of the gap between the core rod 72b of the flow rate adjusting valve 72 and the first communication passage 71A is set sufficiently small, the pressure in the second pressure chamber 114 is the pressure in the first pressure chamber 112. It will be high enough for. When the force for driving the piston assembly 14 downward exceeds the magnetic attraction acting between the latch yoke 20 and the piston assembly 14, the piston assembly 14 begins to descend.

As the piston assembly 14 descends, the magnetic attraction acting between the latch yoke 20 and the piston assembly 14 gradually decreases. On the other hand, the magnetic attraction force acting between the bottom yoke 80 and the piston assembly 14 and the magnetic attraction force acting between the outer yoke 82 and the piston assembly 14 gradually increase.

When the piston assembly 14 is further lowered, the bottom yoke 80 enters the recess 56 of the core yoke 40. After that, the step portion 65 of the cover yoke 44 abuts on the lower damper 98, and the piston assembly 14 reaches the bottom dead center (downward end). When the piston assembly 14 is located at the bottom dead center, the magnetic flux density passing through the work W becomes maximum, and the work W is attracted and held by the magnet chuck 10 with the maximum magnetic attraction force.

The work W may be at room temperature or higher, but may be at a high temperature. When the work W is attracted and held by the magnet chuck 10, the heat of the work W is transferred to the magnet chuck 10. For example, fluororubber used as a material for the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, etc., cannot always withstand extremely high temperatures. When the temperature of the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, etc. becomes extremely high, the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, etc. There is a risk of damage to such things. On the other hand, in the present embodiment, since the first pressure chamber 112 and the second pressure chamber 114 communicate with each other via the communication passage 71 (first communication passage 71A), the piston assembly 14 is located at the bottom dead center. Even in this state, the fluid continues to flow in the first pressure chamber 112. Therefore, according to the present embodiment, the magnet chuck 10 can be cooled by the fluid, and damage to the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, etc. is suppressed. be able to.

The work W is conveyed to a predetermined position while the piston assembly 14 is located at the bottom dead center. That is, the work W is conveyed to a predetermined position while the magnet chuck 10 sucks and holds the work W. After that, an operation for releasing the work W from the magnet chuck 10 is performed. The operation for releasing the work W from the magnet chuck 10 is performed by operating a switching valve (not shown). Specifically, the supply of the fluid into the first pressure chamber 112 is started, and the discharge of the fluid from the second pressure chamber 114 is started. Even when the fluid is supplied to the first pressure chamber 112 and the fluid is discharged from the second pressure chamber 114, the fluid continues to flow in the first pressure chamber 112. Therefore, the magnet chuck 10 is cooled by the fluid even when the fluid is supplied into the first pressure chamber 112 and the fluid is discharged from the second pressure chamber 114.

When the supply of the fluid into the first pressure chamber 112 is started and the discharge of the fluid from the second pressure chamber 114 is started, the force for driving the piston assembly 14 upward is the first pressure. The differential pressure between the chamber 112 and the second pressure chamber 114 acts on the piston assembly 14. Until the force that attempts to drive the piston assembly 14 upward exceeds the magnetic attraction acting between the bottom yoke 80 and the piston assembly 14 and between the outer yoke 82 and the piston assembly 14, the piston assembly 14 remains. Located at bottom dead center. When the force for driving the piston assembly 14 upward exceeds the magnetic attraction acting between the bottom yoke 80 and the piston assembly 14 and between the outer yoke 82 and the piston assembly 14, the piston assembly 14 rises. Begin to.

The magnetic attraction acting on the work W gradually decreases as the piston assembly 14 rises, and the work W is released from the attraction by the magnet chuck 10. When the flange 41 of the seal holder 38 comes into contact with the upper damper 104, the ascending of the piston assembly 14 is completed. That is, the piston assembly 14 reaches top dead center. In the piston assembly 14, in addition to the magnetic attraction acting between the latch yoke 20 and the piston assembly 14, the differential pressure between the first pressure chamber 112 and the second pressure chamber 114 is continuously applied to the piston assembly 14. The piston assembly 14 is securely held at top dead center. Therefore, the piston assembly 14 does not suddenly descend and the work W is not sucked. Even when the piston assembly 14 is held at top dead center, the fluid continues to flow in the first pressure chamber 112. Therefore, the magnet chuck 10 is cooled by the fluid even when the piston assembly 14 is held at the top dead center.

As described above, according to the present embodiment, the first pressure chamber 112 and the second pressure chamber 114 communicate with each other via the communication passage 71 (first communication passage 71A). Therefore, according to the present embodiment, each part of the magnet chuck 10 is cooled by the fluid that continues to flow in the internal space 25 of the cylinder tube 12. Even when the piston assembly 14 is located at the bottom dead center, the fluid continues to flow in the first pressure chamber 112 and the second pressure chamber 114. Therefore, according to the present embodiment, even when the high-temperature work W is attracted by the magnet chuck 10, the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, and the like are damaged. Can be suppressed from being added. Therefore, according to the present embodiment, it is possible to provide the magnet chuck 10 having good heat resistance.

[Second Embodiment]
Next, the magnet chuck according to the second embodiment will be described with reference to FIGS. 5 and 6. The same components as those of the magnet chuck according to the first embodiment shown in FIGS. 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted or simplified. 5 and 6 are cross-sectional views showing a magnet chuck according to the present embodiment. The state in which the piston assembly 14 is located at top dead center is shown in FIG. The state where the piston assembly 14 is located at the bottom dead center is shown in FIG.

As shown in FIGS. 5 and 6, a groove 116 is formed on the wall surface of the internal space 25 of the cylinder tube 12. In the present embodiment, the communication passage 71 (second communication passage 71B) communicating the first pressure chamber 112 and the second pressure chamber 114 is configured by the groove 116. The depth of the groove 116 constituting the second communication passage 71B so as to be able to generate a sufficient differential pressure between the first pressure chamber 112 and the second pressure chamber 114 when driving the piston assembly 14. And the width is set sufficiently small. The second passage 71B is formed on the second side portion 12g of the cylinder tube 12, similarly to the first passage 71A in the first embodiment. As described above, the first side portion 12f and the second side portion 12g are located opposite to each other with respect to the central axis C of the cylinder tube 12. The first supply / discharge port 26 and the second supply / discharge port 76 are provided on the first side portion 12f of the cylinder tube 12, and the second connecting passage 71B is provided on the second side portion 12g of the cylinder tube 12. There is.

The lower end of the groove 116 constituting the second continuous passage 71B reaches the lower damper 98 in which the groove 98a is formed. The first supply / discharge port 26 and the second communication passage 71B communicate with each other via the first pressure chamber 112. Even when the piston assembly 14 is located at the bottom dead center, as shown in FIG. 6, the first supply / discharge port 26 and the second communication passage 71B communicate with each other via the first pressure chamber 112. Is maintained.

The upper end of the groove 116 faces the outer peripheral surface of the small diameter portion 20b of the latch yoke 20. As described above, a gap 114a is formed between the outer peripheral surface of the small diameter portion 20b and the wall surface of the cylinder hole 24. The gap 114a is a part of the second pressure chamber 114 as described above. The second supply / discharge port 76 and the second communication passage 71B communicate with each other via the second pressure chamber 114. Even when the piston assembly 14 is located at the top dead center, as shown in FIG. 5, the second supply / discharge port 76 and the second communication passage 71B communicate with each other via the second pressure chamber 114. Is maintained.

In the above, the case where the second continuous passage 71B is configured by one groove 116 has been described as an example, but the present invention is not limited to this. The second passage 71B may be configured by the plurality of grooves 116. For example, a plurality of grooves 116 may be arranged at predetermined intervals in the circumferential direction of the cylinder hole 24.

As described above, the continuous passage 71 (second continuous passage 71B) may be formed by the groove 116 formed on the wall surface of the internal space 25 of the cylinder tube 12. Also in this embodiment, each part of the magnet chuck 10 is cooled by the fluid that continues to flow in the internal space 25 of the cylinder tube 12. That is, even when the piston assembly 14 is located at the bottom dead center, the fluid continues to flow in the first pressure chamber 112 and the second pressure chamber 114. Therefore, even when the high-temperature work W is attracted by the magnet chuck 10, it is possible to prevent damage to the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, and the like. Can be done. Therefore, also in this embodiment, it is possible to provide the magnet chuck 10 having good heat resistance.

[Third Embodiment]
Next, the magnet chuck according to the third embodiment will be described with reference to FIGS. 7 and 8. The same components as those of the magnet chuck according to the first or second embodiment shown in FIGS. 1 to 6 are designated by the same reference numerals, and the description thereof will be omitted or simplified. 7 and 8 are cross-sectional views showing a magnet chuck according to the present embodiment. The state in which the piston assembly 14 is located at top dead center is shown in FIG. The state where the piston assembly 14 is located at the bottom dead center is shown in FIG.

As shown in FIGS. 7 and 8, the seal holder 38 is formed with a circular hole-shaped recess 85 that opens toward the upper surface side of the magnet chuck 10. The circular recess 85 is open at the bottom surface of the annular recess 51. The central axis of the circular recess 85 coincides with the central axis of the through hole 87a described later. 7 and 8 show an example in which a plurality of circular hole-shaped recesses 85 are formed along the circumferential direction of the piston assembly 14.

The piston assembly 14 is further formed with a communication passage 71 (third communication passage 71C) that communicates the first pressure chamber 112 and the second pressure chamber 114. The third passage 71C is configured by connecting a through hole 87a penetrating the seal holder 38, a through hole 87b penetrating the permanent magnet 42, and a through hole 87c penetrating the ring plate 45 to each other. Not limited. The third communication passage 71C has an opening 83a communicating with the second pressure chamber 114 and an opening 83b communicating with the first pressure chamber 112. The diameter of the third communication passage 71C is set sufficiently small so that a sufficient differential pressure can be generated between the first pressure chamber 112 and the second pressure chamber 114 when driving the piston assembly 14. To. Here, the diameter of the through hole 87a is set sufficiently small so that a sufficient differential pressure can be generated between the first pressure chamber 112 and the second pressure chamber 114 when driving the piston assembly 14. Will be done. The third communication passage 71C is formed at least between the central axis C of the cylinder tube 12 and the second side portion 12g. As described above, the first side portion 12f and the second side portion 12g are located opposite to each other with respect to the central axis C of the cylinder tube 12. The first supply / discharge port 26 and the second supply / discharge port 76 are provided on the first side portion 12f of the cylinder tube 12, and the third connecting passage 71C is the central axis C of the cylinder tube 12 and the second side portion 12g. At least prepared between and. 7 and 8 show an example in which a plurality of third communication passages 71C are formed along the circumferential direction of the piston assembly 14.

The first supply / discharge port 26 and the third communication passage 71C communicate with each other via the first pressure chamber 112. Even when the piston assembly 14 is located at the bottom dead center, as shown in FIG. 8, the first supply / discharge port 26 and the third communication passage 71C communicate with each other via the first pressure chamber 112. Is maintained.

The second supply / discharge port 76 and the third communication passage 71C communicate with each other via the second pressure chamber 114. Even when the piston assembly 14 is located at the top dead center, as shown in FIG. 7, the second supply / discharge port 76 and the third communication passage 71C communicate with each other via the second pressure chamber 114. Is maintained.

As described above, the communication passage 71 (third communication passage 71C) communicating the first pressure chamber 112 and the second pressure chamber 114 may be formed in the piston assembly 14. Also in this embodiment, each part of the magnet chuck 10 is cooled by the fluid that continues to flow in the internal space 25 of the cylinder tube 12. That is, even when the piston assembly 14 is located at the bottom dead center, the fluid continues to flow in the first pressure chamber 112 and the second pressure chamber 114. Therefore, even when the high-temperature work W is attracted by the magnet chuck 10, it is possible to prevent damage to the first sealing material 62, the second sealing material 96, the piston seal 46, the lower damper 98, and the like. Can be done. Therefore, also in this embodiment, it is possible to provide the magnet chuck 10 having good heat resistance.

[Fourth Embodiment]
Next, the magnet chuck according to the fourth embodiment will be described with reference to FIGS. 9 to 11. FIG. 9 is a rear view showing a magnet chuck according to the present embodiment. 10 and 11 are cross-sectional views showing a magnet chuck according to the present embodiment. The state in which the piston assembly 14 is located at the top dead center is shown in FIG. The state in which the piston assembly 14 is located at the bottom dead center is shown in FIG. The same components as those of the magnet chucks according to the first to third embodiments shown in FIGS. 1 to 8 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

In the magnet chuck 10 according to the present embodiment, the direction control valve 134 is provided in the first continuous passage 71Aa.

Similar to the cylinder tube 12 described above in the first to third embodiments, the cylinder tube 12 is formed with a communication passage 71 for communicating the first pressure chamber 112 and the second pressure chamber 114. The communication passage 71 includes the first communication passage 71Aa. A part of the first communication passage 71Aa is formed inside the wall 12a of the cylinder tube 12. The first communication passage 71Aa is formed separately from the internal space 25 of the cylinder tube 12. The first continuous passage 71Aa is provided on the second side portion 12g of the cylinder tube 12 in the same manner as the first continuous passage 71A described above in the first embodiment.

The first communication passage 71Aa includes the first communication hole 74a. The first communication hole 74a in the present embodiment is the same as the first communication hole 74a described above in the first embodiment.

The first communication passage 71Aa further includes a third communication hole 74c. A hole 118 is formed inside the wall 12a of the cylinder tube 12. The hole 118 extends inward of the wall 12a of the cylinder tube 12 toward the bottom of the cylinder tube 12. The hole 118 penetrates the recess 73. A portion of the hole 118 located below the recess 73 constitutes the third communication hole 74c. The upper part of the hole 118 is sealed by the sealing member 120. The upper end of the third communication hole 74c is open on the side surface of the recess 73. The third communication hole 74c extends inside the wall 12a of the cylinder tube 12 toward the lower side of the cylinder tube 12.

The first communication passage 71Aa further includes a fourth communication hole 74d. The lower end of the third communication hole 74c is connected to one end of the fourth communication hole 74d. The other end of the fourth communication hole 74d is open at the second side surface 13B of the cylinder tube 12.

The first communication passage 71Aa further includes a fifth communication hole 74e. The upper end of the fifth communication hole 74e communicates with the screw hole 130 described later. The lower end of the fifth communication hole 74e reaches the annular recess 30 formed in the cylinder tube 12. The first communication passage 71Aa communicates with the first pressure chamber 112 through the groove 98a formed in the lower damper 98, similarly to the first communication passage 71A described above in the first embodiment. That is, the fifth communication hole 74e has an opening 79b that communicates with the first pressure chamber 112. The opening 79b communicating with the first pressure chamber 112 is provided in the second side portion 12g of the cylinder tube 12.

A flow path block 122 is attached to the wall 12a of the cylinder tube 12. The flow path block 122 is attached to the second side portion 12g of the cylinder tube 12. In other words, the flow path block 122 is attached to the back surface of the magnet chuck 10. The flow path block 122 has a side surface 123A and a side surface 123B. The side surface 123A and the side surface 123B are located opposite to each other. The side surface 123A of the flow path block 122 is in contact with the second side surface 13B of the cylinder tube 12.

Inside the flow path block 122, an in-block flow path 124 is formed. The first continuous passage 71Aa further includes the in-block flow path 124. The in-block flow path 124 includes a sixth communication hole 74f. A step portion 144 on which the sealing material 142 is mounted is formed on the side surface 123A of the flow path block 122. One end of the sixth communication hole 74f is open at the step portion 144. The central axis of the sixth communication hole 74f coincides with the central axis of the fourth communication hole 74d. One end of the sixth communication hole 74f communicates with the fourth communication hole 74d. The other end of the sixth communication hole 74f is open at the bottom surface of the recess 132, which will be described later. A sealing material 142 is attached to the step portion 144. The sealing material 142 seals between the second side surface 13B of the cylinder tube 12 and the side surface 123A of the flow path block 122. As the material of the sealing material 142, for example, fluororubber or the like is used, but the material is not limited thereto.

The in-block flow path 124 further includes a seventh communication hole 74g. A hole 126 is formed inside the flow path block 122. The hole 126 extends upward inside the flow path block 122. The hole 126 penetrates the through hole 146, which will be described later. The hole 126 reaches the side surface of the recess 132. A portion of the hole 126 located between the through hole 146 and the recess 132 constitutes the seventh communication hole 74g. The lower part of the hole 126 is sealed by the sealing member 128. The upper end of the seventh communication hole 74g is open on the side surface of the recess 132. The lower end of the seventh communication hole 74g is open on the side surface of the through hole 146.

A screw hole 130 is formed inside the wall 12a of the cylinder tube 12. The tip of the hollow bolt 154, which will be described later, is screwed into the screw hole 130. One end of the screw hole 130 communicates with the fifth communication hole 74e. The other end of the screw hole 130 is open on the second side surface 13B of the cylinder tube 12. A part of the first communication passage 71Aa is formed by the screw hole 130.

A recess 132 is formed in the flow path block 122. The recess 132 is open on the side surface 123B of the flow path block 122. The depth direction of the recess 132 is the direction from the side surface 123B to the side surface 123A. The bottom surface of the recess 132 constitutes a valve seat 132a to which the valve body 134c, which will be described later, abuts.

A directional control valve 134 that controls the direction in which the fluid flows is mounted in the recess 132. A check valve 134A is used as the directional control valve 134. The check valve 134A has a support portion 134a, a spring 134b, and a valve body 134c. The valve body 134c can move with respect to the support portion 134a. The direction in which the valve body 134c moves is the direction along the central axis of the support portion 134a. That is, the direction in which the valve body 134c moves is the depth direction of the recess 132. The spring 134b elastically urges the valve body 134c toward the valve seat 132a. When the pressure in the 6th communication hole 74f is higher than the pressure in the 7th communication hole 74g, the following first force and second force are applied to the valve body 134c. The first force is a force applied to the valve body 134c according to the differential pressure between the 7th communication hole 74g and the 6th communication hole 74f. The second force is the force applied by the spring 134b to the valve body 134c. The direction of the first force and the direction of the second force are opposite to each other. If the first force is greater than the second force, the check valve 134A opens. That is, when the pressure in the 6th communication hole 74f becomes sufficiently higher than the pressure in the 7th communication hole 74g, the check valve 134A opens. If the first force is less than the second force, the check valve 134A is closed. Further, when the pressure in the 6th communication hole 74f is lower than the pressure in the 7th communication hole 74g, the check valve 134A is closed. The check valve 134A allows the flow of fluid from the second pressure chamber 114 to the first pressure chamber 112 through the first communication passage 71Aa. The check valve 134A blocks the flow of fluid from the first pressure chamber 112 toward the second pressure chamber 114 via the first communication passage 71Aa.

The recess 132 is formed with a stepped portion 136 to which a snap ring (C-shaped retaining ring) 138 is mounted. A snap ring 138 is attached to the step portion 136. The directional control valve 134 is fixed in the recess 132 by the snap ring 138.

A sealing material 140 is attached to the directional control valve 134. The sealing material 140 seals between the directional control valve 134 and the recess 132. As the material of the sealing material 140, for example, fluororubber or the like is used, but the material is not limited thereto.

A through hole 146 is formed in the flow path block 122. The central axis of the through hole 146 coincides with the central axis of the screw hole 130. A step portion 148 on which the sealing material 150 is mounted is formed on the side surface 123A of the flow path block 122. One end of the through hole 146 is open at the step portion 148. One end of the through hole 146 communicates with the screw hole 130. A recess 152 in which the head portion 154a of the hollow bolt 154 is housed is formed on the side surface 123B of the flow path block 122. The other end of the through hole 146 is open at the bottom surface of the recess 152.

The flow path block 122 is attached to the wall 12a of the cylinder tube 12 by using a hollow bolt 154. The hollow bolt 154 is provided with a cavity 154b. The central axis of the cavity 154b coincides with the central axis of the hollow bolt 154. The hollow bolt 154 is formed with a hole 154c that reaches the cavity 154b. The central axis of the hole 154c intersects the central axis of the cavity 154b. One end of the cavity 154b communicates with the seventh communication hole 74g via the hole 154c and the through hole 146. The other end of the cavity 154b communicates with the screw hole 130. A part of the flow path 124 in the block is formed by the cavity 154b.

A gasket 156 is attached to the recess 152. The gasket 156 seals between the hollow bolt 154 and the flow path block 122.

The thickness of the upper portion 122a of the flow path block 122 is thinner than the thickness of the portion other than the upper portion 122a of the flow path block 122. A through hole 158 is formed in the upper portion 122a of the flow path block 122. The central axis of the through hole 158 coincides with the central axis of the recess 73. The recess 73 is a screw hole. The tip of the flow rate adjusting valve 72 is screwed into the recess 73. The upper portion 122a of the flow path block 122 is attached to the wall 12a of the cylinder tube 12 by using the flow rate adjusting valve 72.

When the supply of the fluid into the second pressure chamber 114 is started and the discharge of the fluid from the first pressure chamber 112 is started, a differential pressure is generated between the first pressure chamber 112 and the second pressure chamber 114. That is, the force for driving the piston assembly 14 in the direction from the second pressure chamber 114 toward the first pressure chamber 112 corresponds to the differential pressure between the first pressure chamber 112 and the second pressure chamber 114. Works on the piston assembly 14. The first pressure chamber 112 communicates with the seventh communication hole 74g, and the second pressure chamber 114 communicates with the sixth communication hole 74f. Therefore, when the force for driving the piston assembly 14 acts in the direction from the second pressure chamber 114 toward the first pressure chamber 112, the force for opening the check valve 134A acts on the check valve 134A. That is, the force for opening the check valve 134A acts on the check valve 134A according to the differential pressure between the first pressure chamber 112 and the second pressure chamber 114. When the pressure in the second pressure chamber 114 becomes sufficiently higher than the pressure in the first pressure chamber 112, the check valve 134A opens. That is, when the pressure in the 6th communication hole 74f becomes sufficiently higher than the pressure in the 7th communication hole 74g, the check valve 134A opens.

When the supply of the fluid into the first pressure chamber 112 is started and the discharge of the fluid from the second pressure chamber 114 is started, a differential pressure is generated between the first pressure chamber 112 and the second pressure chamber 114. That is, the force for driving the piston assembly 14 in the direction from the first pressure chamber 112 toward the second pressure chamber 114 corresponds to the differential pressure between the first pressure chamber 112 and the second pressure chamber 114. Works on the piston assembly 14. As described above, the first pressure chamber 112 communicates with the seventh communication hole 74g, and the second pressure chamber 114 communicates with the sixth communication hole 74f. Therefore, the pressure in the 6th communication hole 74f is lower than the pressure in the 7th communication hole 74g. Therefore, when the force for driving the piston assembly 14 acts in the direction from the first pressure chamber 112 toward the second pressure chamber 114, the check valve 134A closes. When the directional control valve 134 is closed, the fluid does not flow into the first pressure chamber 112 after the piston assembly 14 reaches top dead center (see FIG. 10). At this stage, since the work W is released from the magnet chuck 10, the magnet chuck 10 is not heated by the work W. That is, at this stage, it is not necessary to cool the magnet chuck 10 with a fluid. Therefore, even if the fluid does not flow into the first pressure chamber 112, there is no particular problem.

As described above, in the present embodiment, when the force for driving the piston assembly 14 acts in the direction from the first pressure chamber 112 to the second pressure chamber 114, the directional control valve 134 closes. According to the present embodiment, since the directional control valve 134 is closed, waste of fluid can be prevented.

(Modification example)
Next, the magnet chuck according to the modified example of this embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a cross-sectional view showing a part of the magnet chuck according to the present embodiment. The state in which the piston assembly 14 is located at top dead center is shown in FIG. FIG. 13 is a block diagram showing a magnet chuck according to the present embodiment.

In the magnet chuck 10 according to this modification, the electromagnetic directional control valve 134B is used as the directional control valve 134.

Similar to the cylinder tube 12 described above in the first to third embodiments, the cylinder tube 12 is formed with a communication passage 71 for communicating the first pressure chamber 112 and the second pressure chamber 114. The communication passage 71 includes the first communication passage 71Ab. A part of the first communication passage 71Ab is formed inside the wall 12a of the cylinder tube 12. The first communication passage 71Ab is formed separately from the internal space 25 of the cylinder tube 12. The first continuous passage 71Ab is provided on the second side portion 12g of the cylinder tube 12 in the same manner as the first continuous passage 71A described above in the first embodiment.

The first communication passage 71Ab includes a first communication hole 74a. The first communication hole 74a in the present embodiment is the same as the first communication hole 74a described above in the first embodiment.

The first communication passage 71Ab further includes a third communication hole 74c. A hole 118 is formed inside the wall 12a of the cylinder tube 12. The hole 118 extends inward of the wall 12a of the cylinder tube 12 toward the bottom of the cylinder tube 12. The hole 118 penetrates the recess 73. A portion of the hole 118 located below the recess 73 constitutes the third communication hole 74c. The upper part of the hole 118 is sealed by the sealing member 120. The upper end of the third communication hole 74c is open on the side surface of the recess 73. The third communication hole 74c extends inside the wall 12a of the cylinder tube 12 toward the lower side of the cylinder tube 12. The lower end of the third communication hole 74c is open on the side surface of the port 160A, which will be described later.

A port 160A is formed on the wall 12a of the cylinder tube 12. The port 160A is open on the second side surface 13B of the cylinder tube 12. The port 160A communicates with the third communication hole 74c.

A port 160B is formed on the wall 12a of the cylinder tube 12. Port 160B is located below port 160A. The port 160B is open on the second side surface 13B of the cylinder tube 12. The port 160B communicates with the fifth communication hole 74e.

As shown in FIG. 13, the electromagnetic directional control valve 134B is provided with ports 164A and 164B. The port 164A communicates with the port 160A via the flow path 166A. The port 164B communicates with the port 160B via the flow path 166B.

The electromagnetic directional control valve 168 is provided with ports 170A, 170B, 170C. A fluid is supplied to the port 170A via the flow path 172. The port 170B communicates with the second supply / discharge port 76 via the flow path 174A. The port 170C communicates with the first supply / discharge port 26 via the flow path 174B.

The control device 176 controls the magnet chuck 10. The control device 176 is provided with, for example, a calculation unit (processing unit) (not shown) and a storage unit (not shown). The arithmetic unit is composed of, for example, a processor such as a CPU (Central Processing Unit). That is, the arithmetic unit is configured by a processing circuit (processing circuit). The magnet chuck 10 is controlled by executing the program stored in the storage unit by the arithmetic unit.

The electromagnetic directional control valves 134B and 168 are switched by a signal supplied from the control device 176. The control device 176 switches the electromagnetic directional control valve 168 to supply the fluid into the second pressure chamber 114 via the second supply / discharge port 76. When the fluid is supplied into the second pressure chamber 114 through the second supply / discharge port 76, the control device 176 switches the electromagnetic direction control valve 134B to allow the flow of the fluid in the first communication passage 71Ab. That is, in such a case, the control device 176 opens the electromagnetic directional control valve 134B to allow the flow of fluid in the first communication passage 71Ab. As a result, the fluid is introduced into the first pressure chamber 112 via the first communication passage 71Ab.

Further, the control device 176 switches the electromagnetic direction control valve 168 to supply the fluid into the first pressure chamber 112 via the first supply / discharge port 26. When the fluid is supplied into the first pressure chamber 112 through the first supply / discharge port 26, the control device 176 switches the electromagnetic direction control valve 134B and blocks the flow of the fluid in the first communication passage 71Ab. That is, in such a case, the control device 176 closes the electromagnetic direction control valve 134B and blocks the flow of the fluid in the first communication passage 71Ab. This prevents the fluid from flowing from the first pressure chamber 112 to the second pressure chamber 114 through the first communication passage 71Ab.

Also in this modification, the direction control valve 134 is closed when the force for driving the piston assembly 14 acts in the direction from the first pressure chamber 112 to the second pressure chamber 114. Therefore, even in this modification, waste of fluid can be prevented.

[Modification Embodiment]
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.

For example, the first embodiment and the second embodiment may be combined. That is, the first continuous passage 71A and the second continuous passage 71B may be provided in the magnet chuck 10.

Further, the first embodiment and the third embodiment may be combined. That is, the first-passage passage 71A and the third-passage passage 71C may be provided in the magnet chuck 10.

Further, the second embodiment and the third embodiment may be combined. That is, the second passage 71B and the third passage 71C may be provided in the magnet chuck 10.

Further, the first embodiment, the second embodiment and the third embodiment may be combined. That is, the magnet chuck 10 may be provided with the first passage 71A, the second passage 71B, and the third passage 71C.

Further, the fourth embodiment and the second embodiment may be combined. That is, the first continuous passage 71Aa and the second continuous passage 71B may be provided in the magnet chuck 10. Further, the modified example of the fourth embodiment and the second embodiment may be combined. That is, the first continuous passage 71Ab and the second continuous passage 71B may be provided in the magnet chuck 10.

Further, the fourth embodiment and the third embodiment may be combined. That is, the first continuous passage 71Aa and the third continuous passage 71C may be provided in the magnet chuck 10. Further, the modified example of the fourth embodiment and the third embodiment may be combined. That is, the first-passage passage 71Ab and the third-passage passage 71C may be provided in the magnet chuck 10.

Further, the fourth embodiment, the second embodiment and the third embodiment may be combined. That is, the magnet chuck 10 may be provided with the first passage 71Aa, the second passage 71B, and the third passage 71C. Further, the modified example of the fourth embodiment and the second embodiment and the third embodiment may be combined. That is, the magnet chuck 10 may be provided with the first passage 71Ab, the second passage 71B, and the third passage 71C.

The above embodiments can be summarized as follows.

The magnet chuck (10) includes a cylinder tube (12) having a work suction surface (12c) to which the work (W) is attracted, and a permanent magnet (42), and inside the internal space (25) of the cylinder tube. A piston assembly (14) that is movable and separates the internal space of the cylinder tube into a first pressure chamber (112) and a second pressure chamber (114), and a first pressure chamber formed in the cylinder tube. A first supply / discharge port (26) communicating with the cylinder tube, a second supply / discharge port (76) formed in the cylinder tube and communicating with the second pressure chamber, the first pressure chamber and the second pressure chamber. It is provided with a communication passage (71) for communicating the above. According to such a configuration, since the communication passage connecting the first pressure chamber and the second pressure chamber is formed, the fluid continues to flow in the first pressure chamber and the second pressure chamber. Even when the piston assembly is located at bottom dead center, fluid continues to flow in the first pressure chamber and the second pressure chamber. Therefore, even when the high-temperature work is attracted by the magnet chuck, it is possible to suppress damage to the components of the magnet chuck. Therefore, according to such a configuration, it is possible to provide a magnet chuck having good heat resistance.

The communication passage includes a first communication passage (71A, 71Aa, 71Ab), and at least a part of the first communication passage is formed inside the wall (12a) of the cylinder tube, and the first communication passage is formed. The passage is formed separately from the internal space of the cylinder tube, and the first communication passage has an opening (79b) communicating with the first pressure chamber and an opening communicating with the second pressure chamber (79b). 79a) and may have.

The first communication passage further includes a damper (98) that cushions the impact generated when the piston assembly is moved in the internal space, and the first communication passage has the first pressure through a groove (98a) formed in the damper. You may communicate with the room.

The first supply / discharge port may communicate with the first pressure chamber through another groove (98a) formed in the damper.

A flow rate adjusting valve (72) for adjusting the flow rate of the fluid flowing through the first continuous passage may be further provided. According to such a configuration, the flow rate of the fluid flowing through the first communication passage can be appropriately adjusted.

The cylinder tube includes a first end portion (12d) including the work suction surface and a second end portion (12e) opposite to the first end portion, and the flow rate adjusting valve is the second end portion. It may be provided in the section. According to such a configuration, a sufficient distance between the work and the flow rate adjusting valve can be secured, so that damage to the sealing material or the like provided in the flow rate adjusting valve can be sufficiently suppressed. can.

The first communication passage may include a communication hole (74a) having the opening communicating with the second pressure chamber, and the central axis of the communication hole may coincide with the central axis of the flow rate adjusting valve.

The first communication passage (71Aa, 71Ab) is further provided with a directional control valve (134) for controlling the direction in which the fluid flows, and the first pressure chamber has the second pressure chamber and the work suction surface. When a force located in between and trying to drive the piston assembly acts in the direction from the second pressure chamber toward the first pressure chamber, the direction control valve opens and tries to drive the piston assembly. When the force acts in the direction from the first pressure chamber to the second pressure chamber, the directional control valve may be closed. With such a configuration, waste of fluid can be prevented.

The directional control valve is a check valve (134A), and the check valve allows the flow of the fluid from the second pressure chamber to the first pressure chamber through the first communication chamber, and also allows the flow of the fluid. The flow of the fluid from the first pressure chamber to the second pressure chamber through the first communication passage may be blocked.

Further comprising a flow path block (122) attached to the wall of the cylinder tube, the first communication passage has an in-block flow path (124) formed inside the flow path block and the check valve. May be provided in the flow path block.

The flow path block may be attached to the wall of the cylinder tube using a hollow bolt (154), and a part of the flow path in the block may be formed by a cavity (154b) provided in the hollow bolt. .. According to such a configuration, it is possible to contribute to miniaturization of the magnet chuck and the like.

The directional control valve is an electromagnetic directional control valve (134B) that is switched by a signal supplied from the control device, and when a fluid is supplied to the second pressure chamber via the second supply / discharge port, the directional control valve is described. When the electromagnetic directional control valve is switched so that the flow of the fluid in the first communication passage is allowed and the fluid is supplied to the first pressure chamber through the first supply / discharge port, the first. The electromagnetic directional control valve may be switched so that the flow of the fluid in the single passage is blocked.

The communication passage may include a second communication passage (71B) composed of a groove (116) formed in the wall surface of the internal space of the cylinder tube.

The communication passage includes a third communication passage (71C) formed in the piston assembly, and the third communication passage communicates with an opening (83b) communicating with the first pressure chamber and communicating with the second pressure chamber. It may have an opening (83a) to be formed.

The cylinder tube includes a first side portion (12f) and a second side portion (12g) located opposite to each other with respect to the central axis (C) of the cylinder tube, and includes the first supply / discharge port and the first supply / discharge port. (2) The supply / discharge port may be provided on the first side portion, and the communication passage may be provided at least between the second side portion or the second side portion and the central axis. According to such a configuration, the components of the magnet chuck can be cooled more effectively, so that a magnet chuck having better heat resistance can be provided.

10: Magnet chuck 12: Cylinder tube 12a: Wall 12b, 21, 39: Recessed groove 12c: Work suction surface 12d: First end 12e: Second end 12f: First side 12g: Second side 13A: 1st side surface 13B: 2nd side surface 14: Piston assembly 16, 138: Snap ring 18: Bottom cover 20: Latch yoke 20a, 41: Flange 20b, 66, 72b2, 102a: Small diameter part 22: Fitting part 23, 32, 65 , 73a, 82c, 136, 144, 148: Step 24: Cylinder hole 25: Internal space 26: First supply / discharge port 27: Latch yoke seal 28: First fluid supply / discharge hole 30, 51: An annular recess 35: Insertion Hole 38: Seal holder 40: Core yoke 42: Permanent magnet 44: Cover yoke 45: Ring plate 46: Piston seal 48, 87a to 87c, 88, 146, 158: Through hole 50: Inward flange 52: Cylindrical protrusion 54 : Screw holes 56, 73, 102, 132, 152: Recesses 60: Fixing screws 60a, 154a: Head 62: First sealing material 64, 72b1, 102b: Large diameter portions 68a, 68b, 72b3: Circular grooves 70a, 70b : Wearing 71: Communication passages 71A, 71Aa, 71Ab: First communication passage 71B: Second communication passage 71C: Third communication passage 72: Flow control valve 72a: Body portion 72b: Core rod 74a: First communication hole 74b: 2nd communication hole 74c: 3rd communication hole 74d: 4th communication hole 74e: 5th communication hole 74f: 6th communication hole 74g: 7th communication hole 75, 77, 140, 142, 150: Sealing material 76: 2nd Supply / discharge ports 79a, 79b, 81a, 81b, 83a, 83b: Opening 80: Bottom yoke 80a, 90: Lower flange 82: Outer yoke 82a: Upper flange 82b: Outer peripheral recess 84: Connecting plate 85: Circular recess 86: Housing 94: Tie rod 96: Second sealing material 98: Lower damper 98a, 116: Groove 104: Upper damper 106: Circular protrusion 110: Second fluid supply / discharge hole 112: First pressure chamber 114: Second pressure chamber 114a: Gap 118, 126, 154c: Hole 120, 128: Sealing member 122: Flow path block 122a: Upper part 123A, 123B: Side surface 124: In-block flow path 130: Screw hole 134: Direction control valve 134A: Check valve 134B, 168: Electromagnetic direction control valve 154: Hollow bolt 154b: Hollow 156: Gasket 160A, 160B, 164A , 164B, 170A-170C: Port 166A, 166B, 172, 174A, 174B: Flow path 176: Control device C: Central axis W: Work

Claims (15)

A cylinder tube having a work suction surface on which the work is sucked, and
A piston assembly that includes a permanent magnet and is movable within the internal space of the cylinder tube and separates the internal space of the cylinder tube into a first pressure chamber and a second pressure chamber.
A first supply / discharge port formed in the cylinder tube and communicating with the first pressure chamber,
A second supply / discharge port formed in the cylinder tube and communicating with the second pressure chamber,
A communication passage connecting the first pressure chamber and the second pressure chamber,
Equipped with a magnet chuck. In the magnet chuck according to claim 1,
The passage includes the first passage, and the passage includes the first passage.
At least a part of the first communication passage is formed inside the wall of the cylinder tube.
The first communication passage is formed separately from the internal space of the cylinder tube.
The first communication passage is a magnet chuck having an opening communicating with the first pressure chamber and an opening communicating with the second pressure chamber. In the magnet chuck according to claim 2,
Further provided with a damper to cushion the impact generated when the piston assembly is moved within the interior space.
The first communication passage is a magnet chuck that communicates with the first pressure chamber through a groove formed in the damper. In the magnet chuck according to claim 3,
The first supply / discharge port is a magnet chuck that communicates with the first pressure chamber through another groove formed in the damper. In the magnet chuck according to any one of claims 2 to 4.
A magnet chuck further provided with a flow rate adjusting valve for adjusting the flow rate of the fluid flowing through the first continuous passage. In the magnet chuck according to claim 5,
The cylinder tube includes a first end portion including the work suction surface and a second end portion opposite to the first end portion.
The flow rate adjusting valve is a magnet chuck provided at the second end portion. In the magnet chuck according to claim 6,
The first communication passage includes a communication hole having the opening communicating with the second pressure chamber.
A magnet chuck in which the central axis of the communication hole and the central axis of the flow rate adjusting valve coincide with each other. In the magnet chuck according to any one of claims 2 to 7.
The first communication passage is further provided with a directional control valve for controlling the direction in which the fluid flows.
The first pressure chamber is located between the second pressure chamber and the work suction surface.
When the force for driving the piston assembly acts in the direction from the second pressure chamber to the first pressure chamber, the directional control valve opens.
A magnet chuck that closes the directional control valve when a force that attempts to drive the piston assembly acts in the direction from the first pressure chamber to the second pressure chamber. In the magnet chuck according to claim 8,
The directional control valve is a check valve.
The check valve allows the flow of the fluid from the second pressure chamber to the first pressure chamber through the first communication chamber, and also allows the flow of the fluid from the first pressure chamber through the first communication passage. A magnet chuck that blocks the flow of the fluid toward the second pressure chamber. In the magnet chuck according to claim 9,
Further provided with a flow path block attached to the wall of the cylinder tube
The first continuous passage has an in-block flow path formed inside the flow path block.
The check valve is a magnet chuck provided in the flow path block. In the magnet chuck according to claim 10,
The flow path block is attached to the wall of the cylinder tube using hollow bolts.
A magnet chuck in which a part of the flow path in the block is formed by a cavity provided in the hollow bolt. In the magnet chuck according to claim 8,
The directional control valve is an electromagnetic directional control valve that is switched by a signal supplied from the control device.
When the fluid is supplied into the second pressure chamber through the second supply / discharge port, the electromagnetic direction control valve is switched so that the flow of the fluid in the first communication passage is allowed, and the first. 1 A magnet chuck in which when the fluid is supplied into the first pressure chamber through a supply / discharge port, the electromagnetic direction control valve is switched so as to block the flow of the fluid in the first communication passage. In the magnet chuck according to any one of claims 1 to 12,
The communication passage is a magnet chuck including a second communication passage composed of a groove formed in a wall surface of the internal space of the cylinder tube. In the magnet chuck according to any one of claims 1 to 13.
The communication passage includes a third communication passage formed in the piston assembly.
The third communication passage is a magnet chuck having an opening communicating with the first pressure chamber and an opening communicating with the second pressure chamber. In the magnet chuck according to any one of claims 1 to 14,
The cylinder tube includes a first side portion and a second side portion located opposite to each other with respect to the central axis of the cylinder tube.
The first supply / discharge port and the second supply / discharge port are provided on the first side portion.
The communication passage is a magnet chuck provided at least between the second side portion or the second side portion and the central axis.

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