JP2004245250A - Hydraulic cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate a lock mechanism for a hydraulic cylinder without providing a dedicated port. <P>SOLUTION: A main piston 21, to which a piston rod 19 is fixed, is housed in a cylinder tube 22 freely to reciprocate, and inside the cylinder tube 22 is divided into a pressure chamber 30 and a pressure chamber 31. A lock sleeve 41 moving between a fastening position for fastening the lock sleeve to the piston rod 19 and a release position for releasing the fastening is assembled in a lock case 24. A lock piston 48 for applying the spring force for pushing to the fastening position to the lock sleeve 41 and for dividing a lock releasing pressure chamber 51 for generating the thrust opposite to the spring force inside the lock case 24 is housed in the lock case 24. The pressure chamber 30 and the lock releasing pressure chamber 51 are communicated with each other through a communication clearance 58. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic cylinder that reciprocates a piston rod in the axial direction by a fluid pressure such as air pressure, and more particularly to a technique that is effective when applied to a hydraulic cylinder having a lock mechanism.
[0002]
[Prior art]
The body assembly line of an automobile is provided with a plurality of steps of joining panel materials formed in a pressing step by spot welding or the like. These steps include an underbody process for forming the base of the vehicle body, a side body process for forming the side surface of the vehicle body, a main body process for forming the skeleton of the vehicle body by joining the underbody and the side body, and a main body process. There is a metal line process for assembling doors and hoods. A plurality of transport vehicles are provided on a vehicle body assembly line having a work stage for these processes, and each panel material is fixed to the transport vehicle and moves on each work stage. The final stage and the first stage of the vehicle body assembly line are connected by a return line, and the transport vehicle is circulated on the vehicle body assembly line (for example, see Patent Document 1).
[0003]
The carrier has a clamp arm, and the panel material arranged on the carrier is fixed by the clamp arm while being positioned at a predetermined position. A pneumatic cylinder is often used as a drive source for swinging the clamp arm, and compressed air is supplied to the pneumatic cylinder by connecting an air pipe to the carrier. However, since the transport vehicle moves between the work stages, it is necessary to remove the air pipe from the transport vehicle when moving. As described above, the pneumatic cylinder provided on the transport trolley at the intermediate work stage where the transport trolley moves is required to have a performance of holding the panel material in a clamped state when the supply of the compressed air is cut off.
[0004]
In order to satisfy this requirement, a pneumatic cylinder equipped with a lock mechanism for fixing a piston rod to which a clamp arm is connected has been developed, and by restricting the movement of the piston rod with the panel material fixed, compressed air is reduced. Even in the disconnected state, the panel material can be held in the clamped state.
[0005]
[Patent Document 1]
JP-A-4-283034 (page 4, FIG. 7)
[0006]
[Problems to be solved by the invention]
However, since the pneumatic cylinder provided with the lock mechanism has a dedicated port for controlling the operation of the lock mechanism, three ports are provided in addition to two supply / discharge ports for reciprocating the piston rod. Providing the three ports in the pneumatic cylinder in this way not only increases the size and cost of the pneumatic cylinder, but also requires a complicated control method for controlling the supply of pneumatic pressure.
[0007]
An object of the present invention is to operate a lock mechanism by simple supply control of a working fluid without providing a dedicated port.
[0008]
[Means for Solving the Problems]
The fluid pressure cylinder of the present invention accommodates a main piston fixed to a piston rod in a reciprocating manner, forms a first pressure chamber on one side of the main piston, and forms a second pressure chamber on the other side of the main piston. A cylinder body that defines a pressure chamber, a fastening position for fastening to the piston rod, and a release position for releasing the fastening with the piston rod are movably incorporated in the cylinder body, and toward the fastening position. A lock sleeve that defines a lock release pressure chamber that generates a thrust opposing the spring force while a spring force is applied, a communication passage communicating the first pressure chamber and the lock release pressure chamber, and the cylinder A first supply / discharge port provided in the body and communicating with the first pressure chamber and the unlocking pressure chamber; and a second pressure provided in the cylinder body. A second supply / discharge port communicating with the main piston. When the piston rod is moved by the working fluid from the second supply / discharge port, the main piston supplied to the unlocking pressure chamber through the communication passage While the lock sleeve is kept released by the back pressure, when the movement of the piston rod is stopped, the lock sleeve is switched to the tightened state with the back pressure drop, and the spring force is changed from the lock sleeve to the piston rod. It is characterized by being transmitted to.
[0009]
The fluid pressure cylinder of the present invention accommodates a main piston fixed to a piston rod in a reciprocating manner, forms a first pressure chamber on one side of the main piston, and forms a second pressure chamber on the other side of the main piston. A cylinder body defining a pressure chamber, a lock sleeve movably incorporated into the cylinder body to a fastening position for fastening to the piston rod, and a release position for releasing fastening to the piston rod; and the cylinder body. A lock piston that defines a lock release pressure chamber in the cylinder body that applies a spring force to the lock sleeve toward the fastening position and generates a thrust opposing the spring force; A communication passage communicating between the pressure chamber and the unlocking pressure chamber; A second supply / discharge port having a first supply / discharge port communicating with an unlocking pressure chamber and a second supply / discharge port provided on the cylinder body and communicating with one of the other of the second pressure chambers; When the piston rod is moved by the working fluid from the above, the lock sleeve is kept in the released state by the back pressure of the main piston supplied to the unlocking pressure chamber through the communication passage, while the movement of the piston rod is When stopped, the lock sleeve is switched to a fastening state in accordance with a decrease in back pressure, and the spring force is transmitted from the lock sleeve to the piston rod.
[0010]
The fluid pressure cylinder according to the present invention is characterized in that the communication passage is a communication gap along an outer peripheral surface of the piston rod.
[0011]
The fluid pressure cylinder according to the present invention is characterized in that a ball member disposed on an outer periphery of the piston rod is pressed against the piston rod by movement of the lock sleeve toward the fastening position.
[0012]
The hydraulic cylinder according to the present invention is characterized in that the lock piston reciprocates in the axial direction of the piston rod.
[0013]
The hydraulic cylinder according to the present invention is characterized in that the lock piston reciprocates in a radial direction of the piston rod.
[0014]
The fluid pressure cylinder according to the present invention is characterized in that a toggle mechanism is provided between the lock piston and the lock sleeve, and a thrust of the lock piston is applied to the lock sleeve via the toggle mechanism.
[0015]
The fluid pressure cylinder according to the present invention is characterized by having a throttle mechanism for controlling the flow of the working fluid discharged from the first supply / discharge port.
[0016]
The fluid pressure cylinder of the present invention is characterized in that it has a release mechanism for manually moving the lock sleeve to the release position.
[0017]
The fluid pressure cylinder of the present invention is characterized in that it has a release mechanism for manually moving the lock piston in opposition to the spring force.
[0018]
The fluid pressure cylinder of the present invention is characterized in that it has a release mechanism for manually moving the ball member in the axial direction of the piston rod.
[0019]
The fluid pressure cylinder according to the present invention is characterized in that the clamp arm is swung by the reciprocation of the piston rod.
[0020]
According to the present invention, since the communication path for communicating the first pressure chamber and the unlocking pressure chamber is provided, when the working fluid is supplied from the second supply / discharge port to move the piston rod, the main piston is moved. The back pressure generated by the movement can be supplied to the unlocking pressure chamber, and the lock sleeve can be held at the unlocking position.
[0021]
As a result, there is no need to provide a dedicated supply / discharge port for controlling the engagement between the lock sleeve and the piston rod, and the supply / discharge control of the working fluid to / from the hydraulic cylinder can be simplified. Cost reduction can be achieved.
[0022]
Further, when the piston rod stops, the back pressure is reduced, so that the lock sleeve can be moved to the fastening position by the spring force, and the spring force can be transmitted to the piston rod via the locked lock sleeve. it can.
[0023]
Thus, for example, when clamping the work using the fluid pressure cylinder, the work can be reliably held.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
FIG. 1 is a plan view showing a part of a vehicle body assembly line in which a panel member constituting a vehicle body is transported by a transport vehicle 10. The transport vehicle 10 has a plurality of wheels 11 and travels from the first work stage S1 to the last work stage Sn. At the first work stage S1, the panel material constituting the vehicle body is carried into the transport trolley 10 as the work W, and at the final work stage Sn, the work W for which the predetermined assembly work has been completed is removed from the transport trolley 10. Each transport carriage 10 is provided with a clamp mechanism 12 for clamping, that is, fastening and fixing the work W. In FIG. 1, two clamp mechanisms 12 are provided for each transport vehicle 10, but any number of clamp mechanisms 12 can be provided on the transport vehicle 10 according to the size of the work W or the like.
[0026]
FIG. 2 is a front view showing the clamp mechanism 12 of FIG. 1, and a hydraulic cylinder 16 according to an embodiment of the present invention is assembled to the clamp mechanism 12. The carrier 10 is provided with a support 13 for supporting the work W. A clamp arm 14 for clamping the work W is mounted on the support 13 so as to be swingable about a pin 15. A hydraulic cylinder 16 is mounted on the support base 13 by a pin 18 at a portion of a clevis 17 fixed to the hydraulic cylinder 16 so as to swing freely. A piston rod 19 of the hydraulic cylinder 16 is attached to the clamp arm 14 via a pin 20. Are linked. When the piston rod 19 moves in a forward direction with a predetermined stroke, that is, a direction in which the piston rod 19 projects from the inside of the fluid pressure cylinder 16, the clamp arm 14 clamps the work W.
[0027]
FIG. 3 is a sectional view showing the hydraulic cylinder 16 of FIG. The fluid pressure cylinder 16 includes a cylinder tube 22 in which a main piston 21 is reciprocally movable in the axial direction, and a lock case 24 attached to the cylinder tube 22 to accommodate a lock unit 23. An end cover 25 is attached to the portion, and a rod cover 26 is attached to an end of the lock case 24. A cylinder body 27 is formed by the cylinder tube 22, the lock case 24, the end cover 25, and the rod cover 26.
[0028]
The main piston 21 accommodated in the cylinder tube 22 divides the interior of the cylinder tube 22 into a clamp release pressure chamber 30 as a first pressure chamber and a clamp pressure chamber 31 as a second pressure chamber. A supply / discharge port 32 as a first supply / discharge port communicating with the pressure chamber 31 is formed on the rod cover 26, and a supply / discharge port 33 as a second supply / discharge port communicating with the pressure chamber 31 is formed on the end cover 25. When compressed air is supplied to the pressure chamber 30 from the supply / discharge port 32, the main piston 21 moves backward toward the clamp release position in the direction of the end cover 25, while compressed air as a working fluid is supplied from the supply / discharge port 33 to the pressure chamber 31. When supplied, the main piston 21 moves forward toward the clamp position in the direction of the rod cover 26.
[0029]
The main piston 21 includes an annular first disk 35 provided with a sealing material 34 and a second disk 37 having a cylindrical portion 36. An internal thread 36 a is provided on the inner peripheral surface of the cylindrical portion 36 of the second disk 37. Is formed. An annular magnet 38 is sandwiched between the first disk 35 and the second disk 37, and the position of the main piston 21 can be detected via the magnet 38 by a sensor (not shown) provided on the cylinder tube 22. It has become.
[0030]
The piston rod 19 having an external thread 19a formed at one end is screw-coupled to the second disk 37 of the main piston 21 via the external thread 19a, and is supported by the rod cover 26 so as to be able to reciprocate. The piston rod 19 fixed to the main piston 21 moves in the axial direction integrally with the main piston 21 by controlling the supply and discharge of compressed air as a working fluid to and from the pressure chamber 31 and the pressure chamber 30.
[0031]
The lock unit 23 accommodated in the lock case 24 is provided with a plurality of steel balls 39 as ball members disposed on the outer periphery of the piston rod 19 and holding the plurality of steel balls 39 and penetrating the piston rod 19. The retainer 40 is slidable with respect to the piston rod 19. Further, the lock unit 23 includes a lock sleeve 41 having a tapered surface 41 a on the outer peripheral side of the retainer 40, and the lock sleeve 41 is slidably received in the lock case 24. As described above, the plurality of steel balls 39 are disposed between the outer peripheral surface 19b of the piston rod 19 and the tapered surface 41a of the lock sleeve 41, and the lock unit 23 is moved by moving the lock sleeve 41 in the axial direction. Is switched between a fastening state in which the steel ball 39 is pressed against the piston rod 19 and a release state in which the pressing on the piston rod 19 is released.
[0032]
A cylindrical spring receiving member 43 with a bottom provided with a flange portion 42 is provided between the lock sleeve 41 and the rod cover 26, and a release is provided between the flange portion 42 of the spring receiving member 43 and the rod cover 26. A spring member 44 is provided. The release spring member 44 urges the lock sleeve 41 toward the release position by a predetermined spring force via the flange portion 42 that contacts the lock sleeve 41. That is, the release spring member 44 urges the lock sleeve 41 in the retreating direction on the end cover 25 side. A holding spring member 46 is provided between the bottom portion 45 of the spring receiving member 43 and the retainer 40, and the retaining spring member 46 moves the retainer 40 in a predetermined direction in the retreating direction of the end cover 25 side. Energized by spring force.
[0033]
A positioning sleeve 47 is provided in the lock case 24 adjacent to the retainer 40. The positioning sleeve 47 is penetrated by the piston rod 19, and one end of the positioning sleeve 47 contacts the lock case 24. As described above, the positioning sleeve 47 abutting on the lock case 24 serves as a stopper for restricting the backward movement of the retainer 40 and the steel ball 39 by the retaining spring member 46 at a predetermined position.
[0034]
An annular lock piston 48 is provided on the outer periphery of the positioning sleeve 47, and the lock piston 48 is slidable with respect to the positioning sleeve 47 and the lock case 24. The inside of the lock case 24 is partitioned by a lock piston 48 into a spring chamber 50 in which a locking spring member 49 is stored and a lock release pressure chamber 51 in which the lock unit 23 is stored. The lock piston 48 is urged by the locking spring member 49 in the forward direction toward the rod cover 26 with a predetermined spring force, while the compressed air supplied to the unlocking pressure chamber 51 causes the lock piston 48 to resist the spring force. As a result, the end cover 25 is urged in a retreating direction by a predetermined thrust. The spring chamber 50 in the lock case 24 is opened to the atmosphere by a communication hole (not shown).
[0035]
Subsequently, a supply flow path for supplying compressed air to the pressure chamber 31, the pressure chamber 30, and the unlocking pressure chamber 51 will be described. FIG. 4 is a sectional view showing the structure of the rod cover 26 along the line AA in FIG. As shown in FIG. 4, three supply / discharge ports 32 are formed in the rod cover 26 in the radial direction, and a supply / discharge pipe is connected to any one of the supply / discharge ports 32 according to a use condition. . This piping is connected to an air pressure source via a flow path switching valve having an exhaust port, and compressed air is supplied to the supply / discharge port 32 by switching operation of the flow path switching valve, while compressed air is supplied from the supply / discharge port 32. The compressed air is discharged. The unused supply / discharge port 32 is closed by the plug 52.
[0036]
A guide cylinder 53 is incorporated inside the rod cover 26, and a flow channel 54 communicating with the three supply / discharge ports 32 is formed on the outer peripheral surface of the guide cylinder 53. A communication hole 56 that communicates with the flow channel 55 formed on the inner peripheral surface of the guide cylinder 53 is formed. A needle 57 as a throttle mechanism is mounted on the guide cylinder 53 so as to enter the communication hole 56, and a needle 57 having a male screw 57 a formed on the outer peripheral surface is screwed into the guide cylinder 53 so that the flow passage cross-sectional area of the communication hole 56 is reduced. The flow, that is, the flow rate of the compressed air passing through the communication hole 56 can be controlled.
[0037]
The compressed air guided to the flow channel 55 through the communication hole 56 is supplied to the pressure chamber 30 and the unlock pressure chamber 51. The inner diameters of the spring receiving member 43, the retainer 40 and the positioning sleeve 47 are set slightly larger than the outer diameters of the piston rod 19, and are provided between the spring receiving member 43, the retainer 40 and the positioning sleeve 47 and the piston rod 19. Is provided with a communication gap 58 as a communication path. Since the flow channel 55 communicating with the supply / discharge port 32 via the communication gap 58 communicates with the pressure chamber 30 and the unlocking pressure chamber 51, the supply / discharge port 32 controls the pressure chamber 30 and the unlocking pressure chamber 51. Supply / discharge control of compressed air can be performed.
[0038]
As shown in FIG. 3, a plurality of supply / discharge ports 33 connected to the pressure chamber 31 are also formed in the end cover 25, and a supply / discharge pipe is connected to any one of the supply / discharge ports 33 according to a use state. Is connected. This pipe is connected to an air pressure source via a flow path switching valve having an exhaust port in the same manner as the above-described pipe, and compressed air is supplied to the supply / discharge port 33 by the switching operation of the flow path switching valve. The compressed air is discharged from the supply / discharge port 33. Therefore, the supply / discharge control of the compressed air to / from the pressure chamber 31 through the supply / discharge port 33 can be performed. The unused supply / discharge port 33 is closed by a plug 59.
[0039]
Next, the operation of the fluid pressure cylinder 16 will be described. FIG. 5A is a cross-sectional view showing a part of the hydraulic cylinder 16 in which the lock unit 23 has been released, and FIG. It is sectional drawing which shows a part.
[0040]
First, the lock when the piston rod 19 and the main piston 21 are moved forward from the state where the main piston 21 is disposed at the retreat limit position on the end cover 25 side, that is, the state where the piston rod 19 is retracted into the cylinder body 27. The operation of the unit 23 will be described.
[0041]
In a state where the main piston 21 is located at the retreat limit position, compressed air is supplied from the supply / discharge port 32 to the pressure chamber 30 and the unlocking pressure chamber 51. Compressed air is supplied to the pressure chamber 30 through a communication gap 58, and compressed air is supplied to the unlocking pressure chamber 51 from the communication gap 58 through a gap between the retainer 40 and the steel ball 39. By the air pressure applied to the unlocking pressure chamber 51, a thrust is applied to the lock piston 48 in a retreating direction to compress the locking spring member 49, and the lock piston 48 retreats toward the end cover 25. The pressure receiving area of the lock piston 48 receiving the air pressure supplied to the pressure chamber 30 is set to an area sufficient to generate a thrust against the spring force of the lock spring member 49.
[0042]
When the lock piston 48 retreats, the lock sleeve 41 also retreats toward the release position together with the lock piston 48 by the spring force from the release spring member 44, and the end face of the lock sleeve 41 and the end face of the rod cover 26 As shown in FIG. 5A, a predetermined clearance C1 is provided therebetween. As described above, when the lock sleeve 41 is operated to the release position, a predetermined clearance C2 is provided between the tapered surface 41a of the sleeve 41 and the steel ball 39. Is released without being pressed.
[0043]
In such a state, when the compressed air in the pressure chamber 30 is discharged from the supply / discharge port 32 and the compressed air is supplied to the pressure chamber 31 from the supply / discharge port 33, the main piston 21 and the piston rod 19 become It is moved in the forward direction indicated by arrow a in FIG. At this time, the air in the pressure chamber 30 is exhausted from the supply / discharge port 32 with the movement of the main piston 21, and the communication chamber 56 communicates with the pressure chamber 30 and the unlocking pressure chamber 51 and the supply / discharge port 32. The discharge flow rate from the supply / discharge port 32 is restricted by the provided needle 57. That is, since the air in the pressure chamber 30 is compressed with the movement of the main piston 21, a back pressure corresponding to the moving speed of the main piston 21 is generated in the pressure chamber 30. The back pressure can be easily set because the needle 57 is an adjustable throttle mechanism.
[0044]
Since the back pressure generated in the pressure chamber 30 is applied to the unlocking pressure chamber 51 via the communication gap 58, a thrust is applied to the lock piston 48 in a retreating direction to compress the locking spring member 49, and the lock piston 48 Will be held in the release position. The pressure receiving area of the lock piston 48 receiving the back pressure generated in the pressure chamber 30 is set to an area sufficient to generate a thrust against the spring force of the locking spring member 49 also by the back pressure.
[0045]
That is, when the piston rod 19 is moved in the forward direction by supplying compressed air to the pressure chamber 31 from the supply / discharge port 33, the lock unit 23 is held in the released state. It becomes possible.
[0046]
Although the case where the piston rod 19 is moved forward in the direction of arrow a by supplying the compressed air to the pressure chamber 31 has been described, the compressed air in the pressure chamber 31 is discharged and the compressed air is supplied to the pressure chamber 30. By doing so, even when the piston rod 19 is moved backward in the direction of arrow b, the pressure chamber 30 and the unlocking pressure chamber 51 are communicated via the communication gap 58, so that the lock unit 23 is in the unlocked state. Become.
[0047]
As described above, when the piston rod 19 is moved forward and backward, the lock unit 23 can be released by the air pressure supplied from the supply / discharge port 32 or the back pressure generated by the movement of the main piston 21. The forward and backward movement of the rod 19 is allowed.
[0048]
Next, the operation of the lock unit that is switched to the engaged state will be described. When the piston rod 19 and the main piston 21 are stopped, that is, when the forward movement of the piston rod 19 is mechanically restricted, or when the supply of the compressed air to the pressure chamber 30 is stopped, the lock unit 23 is stopped. Is switched to the fastening state.
[0049]
When the main piston 21 stops because the forward movement of the piston rod 19 is mechanically restricted, the air in the pressure chamber 30 is discharged from the supply / discharge port 32, and the back pressure in the pressure chamber 30 gradually decreases. I do. Then, the urging force in the retreating direction applied to the lock piston 48 in opposition to the spring force of the locking spring member 49 decreases as the back pressure decreases. When the back pressure decreases and the urging force falls below a predetermined thrust, the lock piston 48 is urged in the forward direction by the spring force of the locking spring member 49, and moves forward while pushing the lock sleeve 41 toward the fastening position. Will be.
[0050]
When the clearance C1 provided between the end surface of the lock sleeve 41 and the end surface of the rod cover 26 is reduced to a predetermined distance, the clearance C2 provided between the tapered surface 41a of the lock sleeve 41 and the steel ball 39. Is lost, and the steel ball 39 comes into contact with the outer peripheral surface 19b of the piston rod 19 and the tapered surface 41a of the lock sleeve 41. This state is a state where the fastening operation of the lock unit 23 has been started.
[0051]
Furthermore, the lock piston 41 is pushed in the forward direction by the lock piston 48, and the clearance between the lock sleeve 41 and the rod cover 26 is reduced to the clearance C3 shown in FIG. When the lock sleeve 41 is pushed to the fastening position, the steel ball 39 is pressed by the piston rod 19 by the lock sleeve 41, and the steel ball 39 bites into the outer peripheral surface of the piston rod 19, that is, the fastening state is established. . As described above, when the lock unit 23 is switched to the fastening state, the forward movement of the piston rod 19 by the main piston 21 is restricted at the stop position.
[0052]
In addition, even when the lock unit 23 is switched to the fastening state, the lock sleeve 41 can move further forward because the predetermined clearance C3 is provided between the lock sleeve 41 and the rod cover 26. It is in a state. The spring force of the locking spring member 49 applied to the lock sleeve 41 fastened to the piston rod 19 is applied from the lock sleeve 41 in the forward direction of the piston rod 19, and the piston rod 19 is further pushed in the forward direction. become. In other words, even when the supply of compressed air from the two supply / discharge ports 32 and 33 is cut off in a state where the lock unit 23 is switched to the fastening state, the size of the clearance C3 can be controlled by the force of the locking spring member 49. Inside, the piston rod 19 has a forward force.
[0053]
Even when the spring receiving member 43 moves forward with the movement of the lock sleeve 41, a holding spring member 46 provided between the retainer 40 for holding the steel ball 39 and the bottom 45 of the spring receiving member 43. Accordingly, the retainer 40 is kept in contact with the positioning sleeve 47, so that the position of the steel ball 39 does not move, and the lock unit 23 can be reliably switched to the fastening state.
[0054]
In the above description, the case where the forward movement of the piston rod 19 is restricted and the main piston 21 stops has been described. However, the main piston 21 is stopped by stopping the compressed air supplied to the pressure chamber 31. Similarly, the lock unit 23 can be switched to the fastening state.
[0055]
Further, even when the piston rod 19 is moved backward, the supply of the compressed air supplied to the pressure chamber 30 is stopped to reduce the pressure, and the internal pressure of the unlocking pressure chamber 51 is also reduced. 23 can be switched to the fastening state.
[0056]
As described above, when the piston rod 19 is moved forward, the movement of the piston rod 19 is mechanically restricted, the supply of the compressed air to the pressure chamber 31 is stopped, and the main piston 21 is stopped. For example, when the compressed air in the pressure chamber 30 is discharged at the time of the backward movement of the 19, the lock unit 23 is switched to the fastening state, and the forward and backward movement of the piston rod 19 by the main piston 21 is restricted.
[0057]
Next, the operation of the clamp mechanism 12 including the above-described fluid pressure cylinder 16 will be described together with the movement of the transport vehicle 10 on the vehicle body assembly line. First, as shown in FIG. 2, the hydraulic cylinder 16 incorporated in the carrier 10 swings the clamp arm 14 toward the workpiece W by moving the piston rod 19 of the hydraulic cylinder 16 forward. The work W mounted on the support base 13 can be tightened and fixed, while the tightening and fixing to the work W can be released by moving the piston rod 19 backward.
[0058]
As shown in FIG. 2, a supply / discharge hose 60 connected to the supply / discharge port 33 and a supply / discharge port 32 are provided on a supply / discharge joint 60 provided on the transport carriage 10 for supplying compressed air to the fluid pressure cylinder 16. And a supply / discharge hose 62 connected to the pressure chamber 31, the supply of compressed air to the pressure chamber 31, the pressure chamber 30, and the unlocking pressure chamber 51, and the discharge of compressed air from these pressure chambers 31, 30, 51. Is performed via the supply / discharge joint 60.
[0059]
As shown in FIG. 1, a supply / discharge joint 63 connected to a supply / discharge joint 60 of the transport carriage 10 is provided on the first work stage S1, and the supply / discharge joint 63 is connected to an air pressure source (not shown). It is connected via a path switching valve. These supply / discharge joints 60 and 63 are connected to each other when the transport carriage 10 is arranged on the first work stage S1, so that compressed air is supplied from the air pressure source to the pressure chambers 31, 30, and 51. The air in the pressure chambers 31, 30, 51 can be discharged to the outside.
[0060]
When the transport carriage 10 is moved to the first work stage S1, compressed air is supplied from the supply / discharge port 32 to the pressure chamber 30 via the supply / discharge joints 60 and 63 connected to each other, while the pressure chamber 31 is supplied. Is discharged from the supply / discharge port 33. With such supply / discharge control, the lock sleeve 41 is moved to the release position with the retraction of the lock piston 48, the lock unit 23 is switched to the release state, and the piston rod 19 is moved in the retreat direction by the main piston 21. You. The clamp arm 14 is opened upward by the retreating movement of the piston rod 19 being drawn into the cylinder main body 27, and the carriage 10 is brought into the state of loading the work W.
[0061]
Subsequently, when the work W is carried into the support table 13 of the carrier 10 by a carrier (not shown), the compressed air supplied to the pressure chamber 30 via the supply / discharge joints 60 and 63 is supplied to the supply / discharge port 32. Then, the supply of compressed air from the supply / discharge port 33 to the pressure chamber 31 is started. With such supply / discharge control, the piston rod 19 moves forward, and the unlocked state of the lock unit 23 is maintained by the back pressure in the pressure chamber 30 increased by the forward movement of the main piston 21.
[0062]
When the piston rod 19 moves forward to protrude from the cylinder body 27 until a predetermined stroke, the tip of the clamp arm 14 that is closed downward contacts the work W, and tightens and fixes the work W. Stop the forward movement. Since the main piston 21 is stopped with the stop of the piston rod 19, the back pressure in the pressure chamber 30, that is, the back pressure in the unlocking pressure chamber 51 gradually decreases, and the lock piston 48 It moves in the forward direction by the spring force.
[0063]
As a result, the lock unit 23 is switched to the engaged state, so that the spring force of the locking spring member 49 is applied in the forward direction of the piston rod 19 via the lock sleeve 41, and the piston rod 19 is further pushed in the forward direction. That is, in the first work stage S1, the work W clamped on the support base 13 by the forward movement of the piston rod 19 by the main piston 21 and the pushing of the piston rod 19 by the locking spring member 49 is in the fastening state. The clamped state is held by the locked unit 23.
[0064]
When work such as spot welding is completed on the first work stage S1 to which the work W is fixed as described above, the carrier 10 is moved to the next work stage S2. At this time, even when the supply and discharge joints 60 and 63 connected to each other are disconnected and the compressed air in the pressure chamber 31 is discharged, the lock unit 23 reduces the spring force of the locking spring member 49. Since the piston W is used to push the piston rod 19 in the forward direction, the clamp of the work W is not released. Therefore, even when vibration or impact is applied during the movement of the transport vehicle 10, the work W is securely clamped without the tightening force of the clamp arm 14 on the work W being loosened.
[0065]
The work W is processed while the transport trolley 10 moves on a plurality of work stages, and when the work on the final work stage Sn is completed, the work W is carried out of the vehicle body assembly line. As shown in FIG. 1, a supply / discharge joint 64 similar to the aforementioned supply / discharge joint 63 is provided on the final work stage Sn. When the transport vehicle 10 is disposed on the final work stage Sn, the supply / discharge joints 60, 64 are connected to each other, so that supply / discharge control of the pressure chambers 31, 30, 51 can be performed.
[0066]
In the final work stage Sn, the compressed air is supplied from the supply / discharge port 32 to the pressure chamber 30 and the unlocking pressure chamber 51, while the air in the pressure chamber 31 is exhausted from the supply / discharge port 33. The lock unit 48 is switched to the released state by the lock piston 48 moving in the retreating direction with the increase in the pressure in the chamber 51. In addition, the piston rod 19 moves backward together with the main piston 21 with an increase in the pressure in the pressure chamber 30. When the clamp arm 14 is opened upward by the retreating movement of the piston rod 19, the transport trolley 10 is switched to the unloading state of the work W, and the processed work W is unloaded by the transfer device. Then, the transport trolley 10 from which the work W has been carried out is moved to the first work stage S1.
[0067]
If the clamp arm 14 is set to be closed when returning the transport carriage 10 to the first work stage S1, compressed air is supplied to the pressure chamber 31 after the work W is carried out at the final work stage Sn. Then, the piston rod 19 is moved forward.
[0068]
As described above, when the pressures in the unlocking pressure chamber 51 and the pressure chamber 30 of the fluid pressure cylinder 16 are released to the atmosphere, the lock unit 23 is in the fastening state, so that the movement of the piston rod 19 is restricted. In order to release the lock unit 23, compressed air needs to be supplied. For example, in the operation of incorporating the fluid pressure cylinder 16 into the clamp mechanism 12 of the transportation vehicle 10, that is, in the operation of manufacturing the transportation vehicle 10, in many cases, compressed air cannot be obtained as needed. In addition, the operation of releasing the lock unit 23 becomes complicated, and the work efficiency in the production operation of the carrier 10 is reduced.
[0069]
Therefore, as shown in FIG. 3, an engagement groove 65 is formed on the outer peripheral surface of the lock piston 48, and a release rod 66 as a release mechanism whose tip enters the engagement groove 65 passes through the lock case 24. It is mounted rotatably. The distal end of the release rod 66 is eccentric. By rotating the release rod 66 with a tool or the like, the lock piston 48 can be moved in the retreating direction in opposition to the spring force of the locking spring member 49. , The lock unit 23 can be switched to the release state. Thereby, the lock unit 23 can be manually released without using compressed air, and for example, the work efficiency in the work of manufacturing the transport vehicle 10 can be improved.
[0070]
FIG. 6 is a sectional view showing a fluid pressure cylinder 70 according to another embodiment of the present invention. In FIG. 6, members common to those shown in FIG. Description is omitted. The fluid pressure cylinder 16 shown in FIG. 6 is a fluid pressure cylinder 70 in which the structure of the lock piston 48 shown in the fluid pressure cylinder 16 of FIG. 3 is changed.
[0071]
As shown in FIG. 6, a piston case 73 extending in a radial direction is formed in a lock case 72 that accommodates the lock unit 71. A lock piston 74 is slidably housed in the piston case 73 so as to be perpendicular to the radial direction of the piston rod 19, that is, the axial direction of the piston rod 19. A taper rod 75 having a taper surface 75 a is formed at the tip of the lock piston 74, and the taper surface 75 a is formed at an acute angle with respect to the axis of the taper rod 75.
[0072]
The interior of the piston case 73 is partitioned by a lock piston 74 into a spring chamber 77 in which locking spring members 76a and 76b are accommodated and a lock release pressure chamber 78. The lock piston 74 is moved by the locking spring members 76a and 76b. While being urged toward the rod 19 by a predetermined spring force, the compressed piston supplied to the unlocking pressure chamber 78 urges the lock piston 74 with a predetermined thrust in a retreating direction against the spring force.
[0073]
The end surface of the lock sleeve 79 on the end cover 25 side is formed as a tapered surface 79 a corresponding to the tapered surface 75 a of the tapered rod 75, and the tapered surface 79 a is formed at an obtuse angle with respect to the axis of the lock sleeve 79. I have.
[0074]
Such a hydraulic cylinder 70 can be operated similarly to the hydraulic cylinder 16 of FIG. That is, when the piston rod 19 is moved forward and backward, the pressure in the unlocking pressure chamber 78 is reduced by the back pressure generated by the movement of the main piston 21 and the air pressure supplied from the supply / discharge port 32 through the communication gap 58. The locking piston 74 can be moved backward to the position shown in FIG. 6 against the spring force of the locking spring members 76a and 76b. Due to the movement of the lock piston 74, the lock sleeve 79 is moved backward to the release position by the spring force of the release spring member 44, so that contact between the lock sleeve 79 and the steel ball 39 is avoided, and the lock unit 71 is released. Can be switched to
[0075]
Further, when the main piston 21 is stopped, for example, when the forward movement of the piston rod 19 is mechanically restricted, or when the supply of the compressed air supplied to the pressure chamber 31 is stopped, the lock release pressure chamber is stopped. The pressure in the unlocking pressure chamber 78 can be reduced by discharging the air in the 78 from the supply / discharge port 32, and the lock piston 74 is moved to the piston rod 19 using the spring force of the lock spring members 76a and 76b. To move forward. Since the lock piston 74 advances the lock sleeve 79 toward the fastening position via the taper rod 75, the lock unit 71 can be switched to the fastening state by pressing the steel ball 39 against the piston rod 19.
[0076]
At this time, the spring force of the locking spring members 76a and 76b is transmitted to the lock sleeve 79 via the tapered surface 75a formed at an acute angle and the tapered surface 79a formed at an obtuse angle. , 76b are transmitted to the lock sleeve 79 in an increased manner. When the lock sleeve 79 moves to the fastening position, the taper rod 75 enters in the retreating direction of the lock sleeve 79, so that the external force applied to the piston rod 19 until the compressed air is supplied to the unlock pressure chamber 78. Thus, the lock unit 71 can be securely held in the fastened state without being affected by the above.
[0077]
Also, in the fluid pressure cylinder 70 of FIG. 6, a release mechanism for manually switching the lock unit 71 to the release state is provided. A positioning sleeve 80 is provided in the lock case 72 adjacent to the retainer 40. The positioning sleeve 80 is provided so as to penetrate the piston rod 19, and has a projection 80a extending in the radial direction. One end of the positioning sleeve 80 is in contact with the retainer 40, and the other end is in contact with the end wall of the lock case 72. As shown by the broken line in FIG. 6, the lock case 72 is provided with a release rod 81 as a release mechanism that can come into contact with the projection 80a of the positioning sleeve 80. The tip of the release rod 81 that comes into contact with the projection 80a is formed in a tapered shape, and a male screw is formed on the outer peripheral surface of the release rod 81. By screwing the release rod 81 using a tool or the like, the distal end of the release rod 81 can be protruded toward the projection 80a, and the positioning sleeve 80 is moved forward on the rod cover 26 side through the contacted projection 80a. Can be moved in any direction.
[0078]
Since the positioning sleeve 80 is in contact with the retainer 40, the retainer 40 and the steel ball 39 are moved in the forward direction as the positioning sleeve 80 moves. Therefore, the steel ball 39 is removed from the tapered surface 79b of the lock sleeve 79, and the pressing of the steel ball 39 against the piston rod 19 is released. Thus, by moving the steel ball 39 as a ball member in the axial direction of the piston rod 19, the lock unit 71 can be switched to the released state without moving the lock piston 74 against the spring force. For example, even when the spring force of the lock spring members 76a and 76b is large and it is difficult to manually move the lock piston 74, the lock unit 71 can be easily switched to the released state.
[0079]
FIG. 7 is a sectional view showing a fluid pressure cylinder 82 according to another embodiment of the present invention, and FIG. 8 is a sectional view showing the fluid pressure cylinder 82 along the line AA in FIG. 7 and 8, members common to those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The fluid pressure cylinder 82 shown in FIG. 7 is a fluid pressure cylinder 82 obtained by changing the structure of the lock piston 48 shown in the fluid pressure cylinder 16 of FIG.
[0080]
As shown in FIG. 7, a piston case 85 is formed in the lock case 84 that accommodates the lock unit 83 so as to extend in the radial direction. A lock piston 86 is slidably accommodated in the piston case 85 so as to be perpendicular to the radial direction of the piston rod 19, that is, the axial direction of the piston rod 19. As shown in FIG. 8, the lock piston 86 includes a cylindrical portion 86 a and two pressing convex portions 86 b extending from the tip thereof, and the lock piston 86 is formed so as to straddle the piston rod 19.
[0081]
The inside of the piston case 85 is divided into a spring chamber 88 in which a lock spring member 87 is accommodated by a lock piston 86 and a lock release pressure chamber 89, and the lock piston 86 advances toward the piston rod 19 by the lock spring member 87. While being biased by a predetermined spring force in the direction, the compressed air supplied to the unlocking pressure chamber 89 is biased by a predetermined thrust in the retreating direction against the spring force.
[0082]
In the lock case 84, a pressing member 91 adjacent to the lock sleeve 90 and a holding member 92 facing the pressing member 91 are slidably accommodated. The pressing member 91 is arranged in contact with the end face of the lock sleeve 90, while the holding member 92 is arranged in contact with the end wall of the lock case 84. Here, FIG. 9 is a perspective view showing the pressing member 91. As shown in FIG. 9, the pressing member 91 includes a semi-cylindrical base 91a and a guide 91b extending therefrom. The base 91a and the guide 91b have a substantially disc-shaped pressing plate abutting on the lock sleeve 90. 91c are provided integrally. A through hole 91d through which the piston rod 19 is inserted is formed at the center of the pressing member 91, and a guide groove 91e is formed on the upper surface of the base 91a so as to reach the pressing plate 91c. The holding member 92 has the same shape as the pressing member 91, and the holding member 92 is arranged such that the pressing plate 92 c contacts the end wall of the lock case 84.
[0083]
As shown in FIGS. 7 and 8, two sets of toggle mechanisms 93 are provided between the upper surfaces of the bases 91 a and 92 a of the holding members 91 and 92 and the lower surface of the pressing protrusion 86 b of the lock piston 86. Each toggle mechanism 93 has two link members 94 and 95. Both ends 94a, 94b, 95a, and 95b of the link members 94 and 95 are chamfered in a smooth arc shape, and a connection end 94a of one of the link members 94 is formed in a convex shape, and a connection of the other link member 95 is formed. The end 95a is formed in a concave shape. A pin hole 96 is formed in each of the connecting ends 94a and 95a, and the connecting pin 97 is inserted into the pin hole 96 in a state where the convex connecting end 94a and the concave connecting end 95a are combined. Inserted, the two link members 94 and 95 are swingably connected via a connecting pin 97.
[0084]
The two sets of toggle mechanisms 93 formed in this manner are bent in a V-shape and disposed between the bases 91a and 92a and the pressing projection 86b, respectively, and the connecting ends 94a and 95a of the link members 94 and 95. Abuts against the lower surface of the pressing projection 86b, while the open ends 94b and 95b of the link members 94 and 95 are guided by guide grooves 91e and 92e formed in the pressing member 91 and the holding member 92, respectively.
[0085]
When the lock piston 86 is urged in the forward direction by the lock spring member 87, the lock piston 86 is pushed down in the range of the clearance α shown in FIG. 7, and the connection ends 94a and 95a are also lowered via the pressing protrusion 86b. Is pushed down. At this time, since the downward movement of the open ends 94b and 95b is restricted by the pressing member 91 and the holding member 92, the link members 94 and 95 of the toggle mechanism 93 are expanded, and the open ends 94b of the link members 94 and 95 are opened. , 95b move away from each other. Further, since the movement of the holding member 92 is regulated by the end wall of the lock case 84, the position of the open end 95 b of the link member 95 does not change, and the open end 94 b of the link member 94 is connected to the lock sleeve 90. I will move toward it. Due to the movement of the open end 94b, the pressing member 91 moves while pushing the lock sleeve 90 toward the fastening position, so that the lock unit 83 can be switched to the fastening state.
[0086]
The contact portion of the open end 94b that contacts the guide groove 91e of the pressing member 91 is set at the same height as the center of the piston rod 19 as shown in FIGS. The thrust of the piston 86 can be transmitted to the lock sleeve 90.
[0087]
Such a hydraulic cylinder 82 can be operated similarly to the hydraulic cylinder 16 of FIG. That is, when the piston rod 19 is moved forward and backward, the pressure in the unlocking pressure chamber 89 is reduced by the back pressure generated by the movement of the main piston 21 and the air pressure supplied from the supply / discharge port 32 through the communication gap 58. The lock piston 86 can be moved backward to the position shown in FIG. 7 against the spring force of the lock spring member 87. The movement of the lock piston 86 releases the spring force of the release spring member 44, and moves the lock sleeve 90 backward to the release position. Therefore, the lock unit 83 avoids the contact between the lock sleeve 90 and the steel ball 39, and Can be switched to the release state.
[0088]
Further, when the main piston 21 is stopped, for example, when the forward movement of the piston rod 19 is mechanically restricted, or when the supply of the compressed air supplied to the pressure chamber 31 is stopped, the lock release pressure chamber is stopped. The pressure in the unlocking pressure chamber 89 can be reduced by discharging the air in the 89 from the supply / discharge port 32, and the lock piston 86 is directed toward the piston rod 19 using the spring force of the lock spring member 87. Can be moved forward. Since the lock piston 86 advances the lock sleeve 90 toward the fastening position via the toggle mechanism 93, the lock unit 83 can be switched to the fastening state by pressing the steel ball 39 against the piston rod 19.
[0089]
At this time, since the spring force of the locking spring member 87 is transmitted to the lock sleeve 90 via the toggle mechanism 93, the spring force of the locking spring member 87 is increased and transmitted to the lock sleeve 90. When the lock sleeve 90 moves to the fastening position, the toggle mechanism 93 in which the link members 94 and 95 are expanded is arranged in the retreating direction of the lock sleeve 90, so that compressed air is supplied to the unlock pressure chamber 89. Until then, the lock unit 83 can be securely held in the fastened state without being affected by external force or the like applied to the piston rod 19.
[0090]
Thus, by using the toggle mechanism 93, the thrust of the lock piston 86 can be increased and transmitted to the lock sleeve 90, and the power transmission efficiency can be improved. The force can be set small, and downsizing of the fluid pressure cylinder 82 can be achieved.
[0091]
The release mechanism shown in FIG. 3 or FIG. 6 may be provided also in the fluid pressure cylinder 82 of FIG. In addition, the toggle mechanism 93 includes two link members 94 and 95, but a toggle mechanism including more link members may be provided. For example, a toggle mechanism that is bent in a W shape using four link members can be used.
[0092]
FIG. 10 is a front view showing a clamp mechanism 99 provided with a fluid pressure cylinder 98 according to another embodiment of the present invention, and FIG. 11 is a sectional view showing the fluid pressure cylinder 98 of FIG. 10 and 11, the same reference numerals are given to members common to the members shown in FIGS. 2 and 3, and the description thereof will be omitted.
[0093]
While the clamp mechanism 12 shown in FIG. 2 closes the clamp arm 14 by the forward movement of the piston rod 19, the clamp mechanism 99 shown in FIG. 10 closes the clamp arm 14 by the backward movement of the piston rod 19. I have to. As shown in FIG. 11, as a hydraulic cylinder 98 provided in such a clamp mechanism 99, piston rods 19 and 100 are attached to both ends of a main piston 21, and the piston rod 100 connected to the clamp arm 14 is a cylinder. The tube 22 projects through the rod cover 101 provided on the tube 22 to the outside. The pressure chamber 31 provided in the fluid pressure cylinder 98 generates an urging force for moving the piston rods 19, 100 in the retreating direction on the rod cover 26 side, while the pressure chamber 30 presses the piston rods 19, 100 on the rod cover 101 side. In the forward direction.
[0094]
When the piston rods 19 and 100 are moved forward and backward, the fluid pressure cylinder 98 is supplied from the back pressure generated by the movement of the main piston 21 and the supply / discharge port 32, similarly to the fluid pressure cylinder 16 of FIG. While the lock unit 23 can be switched to the released state by the air pressure, the backward movement of the piston rods 19 and 100 is mechanically restricted, or the supply of the compressed air supplied to the pressure chamber 31 is stopped. In some cases, when the main piston 21 stops, the lock unit 23 can be switched to the engaged state.
[0095]
As described above, in the fluid pressure cylinders 16, 70, 82, and 98 of the present invention, the pressure chamber 30 communicates with the unlocking pressure chambers 51, 78, and 89, so that the clamp arm 14 tightens the work W. By stopping the movement of the piston rod 19 at the time of fixing, the lock units 23 and 71 can be operated to hold the clamped position of the clamp arm 14. Accordingly, it is not necessary to provide a dedicated supply / discharge port for controlling the operation of the lock units 23 and 71, and the fluid pressure does not require the supply / discharge control of the compressed air for controlling the operation of the lock units 23 and 71. It can be a cylinder 16, 70, 82, 98. Therefore, the size reduction and cost reduction of the fluid pressure cylinders 16, 70, 82, 98 can be achieved.
[0096]
Further, since the unlocking pressure chambers 51, 78, 89 and the pressure chamber 30 communicate with the supply / discharge port 32 through the communication gap 58 along the outer peripheral surface of the piston rod 19, a hole as a flow path is formed in the member. Therefore, the size and cost of the fluid pressure cylinders 16, 70, 82, 98 can be reduced.
[0097]
In the fluid pressure cylinders 16 and 98 shown in FIGS. 2 and 11, the lock sleeve 41 and the lock piston 48 are provided separately for reasons of material, processing, assembly, and the like. The lock piston 48 may be integrally formed, or the lock piston 48 may be integrally fixed to the lock sleeve 41. In this manner, when the configuration is such that the operation of the lock piston 48 is satisfied by one lock sleeve, the number of parts can be reduced, and the cost of the fluid pressure cylinders 16 and 98 can be reduced.
[0098]
The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention. For example, although the fluid pressure cylinders 16, 70, 82, 98 are used for clamping panel materials constituting an automobile body, they may be used for clamping other than panel materials, and may be used for applications other than clamping. It can also be used.
[0099]
Further, the guide cylinder 53 is provided with a needle 57 as a throttle mechanism. If the pressure chamber 30 and the unlocking pressure chambers 51 and 78 communicate with the supply / discharge port 32, for example, the guide cylinder 53 may be used. A throttle mechanism may be provided in another flow path such as the flow grooves 54 and 55 of the body 53. The throttle mechanism is not limited to the needle 57, but may be any throttle mechanism that controls the flow of the working fluid, that is, the flow rate, the flow velocity, and the pressure. For example, a throttle plate having an orifice formed in the flow path may be provided. . Further, when a predetermined resistance is given to the working fluid depending on the structure of the flow path, or when a throttle mechanism is provided in a pipe connected to the supply / discharge port 32, the throttles from the fluid pressure cylinders 16, 70, 82, 98 are used. The mechanism may be removed.
[0100]
Further, when operating the lock units 23 and 71, the steel ball 39 is pressed against the piston rod 19, but a ball member using not only the steel ball 39 but also another material may be used. Further, another member may be used in place of the ball member. For example, a member in which a slit is formed on the inner peripheral surface of an annular member and the inner diameter is reduced by elastic deformation may be used. good.
[0101]
Further, in the fluid pressure cylinders 16 and 98 shown in FIG. 3 or FIG. 11, a release mechanism for manually moving the lock sleeve 41 to the release position and a release mechanism for moving the steel ball 39 in the axial direction of the piston rod 19 are provided. The hydraulic cylinder 70 shown in FIG. 6 may be provided with a release mechanism for moving the lock piston 74 in the backward direction in opposition to the spring force of the lock spring members 76a and 76b. .
[0102]
In addition, although air is used as the working fluid when operating the fluid pressure cylinders 16, 70, 82, 98, it goes without saying that other fluids may be used.
[0103]
【The invention's effect】
According to the present invention, since the communication path for communicating the first pressure chamber and the unlocking pressure chamber is provided, when the working fluid is supplied from the second supply / discharge port to move the piston rod, the main piston is moved. The back pressure generated by the movement can be supplied to the unlocking pressure chamber, and the lock sleeve can be held at the unlocking position.
[0104]
As a result, there is no need to provide a dedicated supply / discharge port for controlling the engagement between the lock sleeve and the piston rod, and the supply / discharge control of the working fluid to / from the hydraulic cylinder can be simplified. Cost reduction can be achieved.
[0105]
Further, when the piston rod stops, the back pressure is reduced, so that the lock sleeve can be moved to the fastening position by the spring force, and the spring force can be transmitted to the piston rod via the locked lock sleeve. it can.
[0106]
Thus, for example, when clamping the work using the fluid pressure cylinder, the work can be reliably held.
[Brief description of the drawings]
FIG. 1 is a plan view showing a part of a vehicle body assembly line in which a panel material constituting a vehicle body is transported by a transport vehicle.
FIG. 2 is a front view showing the clamp mechanism of FIG. 1;
FIG. 3 is a sectional view showing a fluid pressure cylinder according to the embodiment of the present invention shown in FIG. 2;
FIG. 4 is a cross-sectional view showing a structure of a rod cover taken along line AA of FIG. 3;
FIG. 5A is a cross-sectional view illustrating a part of the hydraulic cylinder in which the lock unit is released, and FIG. 5B is a cross-sectional view illustrating a part of the hydraulic cylinder in which the lock unit is engaged. FIG.
FIG. 6 is a sectional view showing a fluid pressure cylinder according to another embodiment of the present invention.
FIG. 7 is a sectional view showing a hydraulic cylinder according to another embodiment of the present invention.
FIG. 8 is a sectional view taken along line AA of FIG. 7;
FIG. 9 is a perspective view showing a pressing member.
FIG. 10 is a front view showing a clamp mechanism provided with a fluid pressure cylinder according to another embodiment of the present invention.
FIG. 11 is a sectional view showing the fluid pressure cylinder of FIG. 10;
[Explanation of symbols]
10 transport trolley
11 wheels
12 Clamp mechanism
13 Support
14 Clamp arm
15 pin
16 Fluid pressure cylinder
17 Clevis
18 pin
19 Piston rod
19a male screw
19b Outer surface
20 pins
21 Main piston
22 cylinder tube
23 Lock unit
24 Lock Case
25 End cover
26 Rod cover
27 Cylinder body
30 Clamp release pressure chamber (first pressure chamber)
31 Clamp pressure chamber (second pressure chamber)
32 supply / discharge port (first supply / discharge port)
33 Supply / discharge port (second supply / discharge port)
34 Sealing material
35 First Disc
36 cylindrical part
36a female screw
37 Second disk
38 magnet
39 steel balls (ball members)
40 cage
41 Lock Sleeve
41a tapered surface
42 Flange
43 Spring receiving member
44 Release spring member
45 bottom
46 Holding spring member
47 Positioning Sleeve
48 Lock Piston
49 Lock Spring Member
50 Spring Chamber
51 Lock release pressure chamber
52 plug
53 Guide cylinder
54, 55 Channel groove
56 communication hole
57 Needle (throttle mechanism)
57a male screw
58 Communication gap (communication passage)
59 plug
60 Supply / discharge joint
61, 62 supply / discharge hose
63, 64 supply / discharge joint
65 engagement groove
66 Release rod (release mechanism)
70 Fluid pressure cylinder
71 Lock unit
72 Lock Case
73 piston case
74 lock piston
75 taper rod
75a tapered surface
76a, 76b Spring member for locking
77 Spring Chamber
78 Lock release pressure chamber
79 Lock Sleeve
79a, 79b Tapered surface
80 Positioning sleeve
80a convex
81 Release rod (release mechanism)
82 fluid pressure cylinder
83 Lock Unit
84 Lock Case
85 piston case
86 lock piston
86a cylindrical part
86b Pressing convex
87 Lock spring member
88 Spring Chamber
89 Lock release pressure chamber
90 Lock Sleeve
91 Pressing member
91a base
91b Guide section
91c Press plate
91d through hole
91e Guide groove
92 Holding member
92a base
92c pressing plate
92e Guide groove
93 toggle mechanism
94,95 link members
94a, 95a connection end
94b, 95b open end
96 pin hole
97 Connecting pin
98 fluid pressure cylinder
99 Clamp mechanism
100 piston rod
101 Rod cover

Claims (12)

A cylinder body accommodating a main piston fixed to a piston rod in a reciprocating manner, defining a first pressure chamber on one side of the main piston, and defining a second pressure chamber on the other side of the main piston. When,
The piston is movably incorporated into a cylinder body at a fastening position for fastening to the piston rod and a release position for canceling fastening with the piston rod, and a spring force is applied toward the fastening position. A lock sleeve that defines a lock release pressure chamber that generates a thrust opposing the lock sleeve;
A communication passage communicating the first pressure chamber and the unlocking pressure chamber;
A first supply / discharge port provided in the cylinder body and communicating with the first pressure chamber and the unlocking pressure chamber;
A second supply / discharge port provided in the cylinder body and communicating with the second pressure chamber;
When the piston rod is moved by the working fluid from the second supply / discharge port, the lock sleeve is kept in an unlocked state by the back pressure of the main piston supplied through the communication passage to the unlock pressure chamber, A fluid pressure cylinder, wherein when the movement of the piston rod is stopped, the lock sleeve is switched to a fastened state as the back pressure decreases, and the spring force is transmitted from the lock sleeve to the piston rod. A cylinder body accommodating a main piston fixed to a piston rod in a reciprocating manner, defining a first pressure chamber on one side of the main piston, and defining a second pressure chamber on the other side of the main piston. When,
A lock sleeve that is movably incorporated into the cylinder body to a fastening position for fastening to the piston rod, and a release position for canceling fastening with the piston rod;
A lock piston that is housed in the cylinder body and defines a lock release pressure chamber in the cylinder body that applies a spring force toward the fastening position to the lock sleeve and generates a thrust opposing the spring force;
A communication passage communicating the first pressure chamber and the unlocking pressure chamber;
A first supply / discharge port provided in the cylinder body and communicating with the first pressure chamber and the unlocking pressure chamber;
A second supply / discharge port provided in the cylinder body and communicating with the second pressure chamber;
When the piston rod is moved by the working fluid from the second supply / discharge port, the lock sleeve is kept in an unlocked state by the back pressure of the main piston supplied through the communication passage to the unlock pressure chamber, A fluid pressure cylinder, wherein when the movement of the piston rod is stopped, the lock sleeve is switched to a fastened state as the back pressure decreases, and the spring force is transmitted from the lock sleeve to the piston rod. 3. The fluid pressure cylinder according to claim 1, wherein the communication passage is a communication gap along an outer peripheral surface of the piston rod. 4. The hydraulic cylinder according to claim 1, wherein the ball member disposed on the outer periphery of the piston rod is pressed by the piston rod by the movement of the lock sleeve toward the fastening position. 5. A hydraulic cylinder characterized by the following. The hydraulic cylinder according to any one of claims 2 to 4, wherein the lock piston reciprocates in an axial direction of the piston rod. The hydraulic cylinder according to any one of claims 2 to 4, wherein the lock piston reciprocates in a radial direction of the piston rod. 7. The hydraulic cylinder according to claim 6, wherein a toggle mechanism is provided between the lock piston and the lock sleeve, and a thrust of the lock piston is applied to the lock sleeve via the toggle mechanism. Fluid pressure cylinder. The hydraulic cylinder according to any one of claims 1 to 7, further comprising a throttle mechanism for controlling a flow of a working fluid discharged from the first supply / discharge port. The hydraulic cylinder according to any one of claims 1 to 8, further comprising a release mechanism for manually moving the lock sleeve to the release position. The fluid pressure cylinder according to any one of claims 2 to 9, further comprising a release mechanism for manually moving the lock piston in opposition to the spring force. The hydraulic cylinder according to any one of claims 4 to 10, further comprising a release mechanism that manually moves the ball member in the axial direction of the piston rod. The fluid pressure cylinder according to any one of claims 1 to 11, wherein the clamp arm is swung by reciprocation of the piston rod.

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